Adding upstream version 247.3.upstream/247.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

165 files changed, 72067 insertions, 0 deletions

diff --git a/src/libsystemd-network/arp-util.c b/src/libsystemd-network/arp-util.c
new file mode 100644
index 0000000..327fb2f
--- /dev/null
+++ b/src/libsystemd-network/arp-util.c
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Axis Communications AB. All rights reserved.
+***/
+
+#include <arpa/inet.h>
+#include <linux/filter.h>
+#include <netinet/if_ether.h>
+
+#include "arp-util.h"
+#include "fd-util.h"
+#include "unaligned.h"
+#include "util.h"
+
+int arp_network_bind_raw_socket(int ifindex, be32_t address, const struct ether_addr *eth_mac) {
+        struct sock_filter filter[] = {
+                BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0),                                         /* A <- packet length */
+                BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(struct ether_arp), 1, 0),           /* packet >= arp packet ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0),                       /* header == ethernet ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0),                       /* protocol == IP ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hln)), /* A <- hardware address length */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct ether_addr), 1, 0),          /* length == sizeof(ether_addr)? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pln)), /* A <- protocol address length */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct in_addr), 1, 0),             /* length == sizeof(in_addr) ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_op)),  /* A <- operation */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0),                      /* protocol == request ? */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 1, 0),                        /* protocol == reply ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                /* Sender Hardware Address must be different from our own */
+                BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be32(&eth_mac->ether_addr_octet[0])),/* A <- 4 bytes of client's MAC */
+                BPF_STMT(BPF_MISC + BPF_TAX, 0),                                               /* X <- A */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_sha)),       /* A <- 4 bytes of SHA */
+                BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0),                                        /* A xor X */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 6),                                  /* A == 0 ? */
+                BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be16(&eth_mac->ether_addr_octet[4])),/* A <- remainder of client's MAC */
+                BPF_STMT(BPF_MISC + BPF_TAX, 0),                                               /* X <- A */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, arp_sha) + 4),   /* A <- remainder of SHA */
+                BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0),                                        /* A xor X */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1),                                  /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+                /* Sender Protocol Address or Target Protocol Address must be equal to the one we care about */
+                BPF_STMT(BPF_LD + BPF_IMM, htobe32(address)),                                  /* A <- clients IP */
+                BPF_STMT(BPF_MISC + BPF_TAX, 0),                                               /* X <- A */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_spa)),       /* A <- SPA */
+                BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0),                                        /* X xor A */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1),                                  /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 65535),                                              /* return all */
+                BPF_STMT(BPF_LD + BPF_IMM, htobe32(address)),                                  /* A <- clients IP */
+                BPF_STMT(BPF_MISC + BPF_TAX, 0),                                               /* X <- A */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_tpa)),       /* A <- TPA */
+                BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0),                                        /* X xor A */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1),                                  /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 65535),                                              /* return all */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+        };
+        struct sock_fprog fprog = {
+                .len = ELEMENTSOF(filter),
+                .filter = (struct sock_filter*) filter
+        };
+        union sockaddr_union link = {
+                .ll.sll_family = AF_PACKET,
+                .ll.sll_protocol = htobe16(ETH_P_ARP),
+                .ll.sll_ifindex = ifindex,
+                .ll.sll_halen = ETH_ALEN,
+                .ll.sll_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
+        };
+        _cleanup_close_ int s = -1;
+        int r;
+
+        assert(ifindex > 0);
+
+        s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (s < 0)
+                return -errno;
+
+        r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
+        if (r < 0)
+                return -errno;
+
+        r = bind(s, &link.sa, sizeof(link.ll));
+        if (r < 0)
+                return -errno;
+
+        return TAKE_FD(s);
+}
+
+static int arp_send_packet(int fd, int ifindex,
+                           be32_t pa, const struct ether_addr *ha,
+                           bool announce) {
+        union sockaddr_union link = {
+                .ll.sll_family = AF_PACKET,
+                .ll.sll_protocol = htobe16(ETH_P_ARP),
+                .ll.sll_ifindex = ifindex,
+                .ll.sll_halen = ETH_ALEN,
+                .ll.sll_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
+        };
+        struct ether_arp arp = {
+                .ea_hdr.ar_hrd = htobe16(ARPHRD_ETHER), /* HTYPE */
+                .ea_hdr.ar_pro = htobe16(ETHERTYPE_IP), /* PTYPE */
+                .ea_hdr.ar_hln = ETH_ALEN, /* HLEN */
+                .ea_hdr.ar_pln = sizeof(be32_t), /* PLEN */
+                .ea_hdr.ar_op = htobe16(ARPOP_REQUEST), /* REQUEST */
+        };
+        int r;
+
+        assert(fd >= 0);
+        assert(pa != 0);
+        assert(ha);
+
+        memcpy(&arp.arp_sha, ha, ETH_ALEN);
+        memcpy(&arp.arp_tpa, &pa, sizeof(pa));
+
+        if (announce)
+                memcpy(&arp.arp_spa, &pa, sizeof(pa));
+
+        r = sendto(fd, &arp, sizeof(struct ether_arp), 0, &link.sa, sizeof(link.ll));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+int arp_send_probe(int fd, int ifindex,
+                    be32_t pa, const struct ether_addr *ha) {
+        return arp_send_packet(fd, ifindex, pa, ha, false);
+}
+
+int arp_send_announcement(int fd, int ifindex,
+                          be32_t pa, const struct ether_addr *ha) {
+        return arp_send_packet(fd, ifindex, pa, ha, true);
+}
diff --git a/src/libsystemd-network/arp-util.h b/src/libsystemd-network/arp-util.h
new file mode 100644
index 0000000..2dac8cf
--- /dev/null
+++ b/src/libsystemd-network/arp-util.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014 Axis Communications AB. All rights reserved.
+***/
+
+#include <net/ethernet.h>
+
+#include "socket-util.h"
+#include "sparse-endian.h"
+
+int arp_network_bind_raw_socket(int index, be32_t address, const struct ether_addr *eth_mac);
+
+int arp_send_probe(int fd, int ifindex,
+                   be32_t pa, const struct ether_addr *ha);
+int arp_send_announcement(int fd, int ifindex,
+                          be32_t pa, const struct ether_addr *ha);
diff --git a/src/libsystemd-network/dhcp-client-internal.h b/src/libsystemd-network/dhcp-client-internal.h
new file mode 100644
index 0000000..a6f3752
--- /dev/null
+++ b/src/libsystemd-network/dhcp-client-internal.h
@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+extern const struct hash_ops dhcp_option_hash_ops;
diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c
new file mode 100644
index 0000000..ea9c77a
--- /dev/null
+++ b/src/libsystemd-network/dhcp-identifier.c
@@ -0,0 +1,215 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <linux/if_infiniband.h>
+#include <net/if_arp.h>
+
+#include "sd-device.h"
+#include "sd-id128.h"
+
+#include "dhcp-identifier.h"
+#include "dhcp6-protocol.h"
+#include "network-internal.h"
+#include "siphash24.h"
+#include "sparse-endian.h"
+#include "stdio-util.h"
+#include "udev-util.h"
+#include "virt.h"
+
+#define HASH_KEY       SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
+#define APPLICATION_ID SD_ID128_MAKE(a5,0a,d1,12,bf,60,45,77,a2,fb,74,1a,b1,95,5b,03)
+#define USEC_2000       ((usec_t) 946684800000000) /* 2000-01-01 00:00:00 UTC */
+
+int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len, bool strict) {
+        struct duid d;
+
+        assert_cc(sizeof(d.raw) >= MAX_DUID_LEN);
+        if (duid_len > MAX_DUID_LEN)
+                return -EINVAL;
+
+        if (!strict)
+                /* Strict validation is not requested. We only ensure that the
+                 * DUID is not too long. */
+                return 0;
+
+        switch (duid_type) {
+        case DUID_TYPE_LLT:
+                if (duid_len <= sizeof(d.llt))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_EN:
+                if (duid_len != sizeof(d.en))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_LL:
+                if (duid_len <= sizeof(d.ll))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_UUID:
+                if (duid_len != sizeof(d.uuid))
+                        return -EINVAL;
+                break;
+        default:
+                /* accept unknown type in order to be forward compatible */
+                break;
+        }
+        return 0;
+}
+
+int dhcp_identifier_set_duid_llt(struct duid *duid, usec_t t, const uint8_t *addr, size_t addr_len, uint16_t arp_type, size_t *len) {
+        uint16_t time_from_2000y;
+
+        assert(duid);
+        assert(len);
+        assert(addr);
+
+        if (arp_type == ARPHRD_ETHER)
+                assert_return(addr_len == ETH_ALEN, -EINVAL);
+        else if (arp_type == ARPHRD_INFINIBAND)
+                assert_return(addr_len == INFINIBAND_ALEN, -EINVAL);
+        else
+                return -EINVAL;
+
+        if (t < USEC_2000)
+                time_from_2000y = 0;
+        else
+                time_from_2000y = (uint16_t) (((t - USEC_2000) / USEC_PER_SEC) & 0xffffffff);
+
+        unaligned_write_be16(&duid->type, DUID_TYPE_LLT);
+        unaligned_write_be16(&duid->llt.htype, arp_type);
+        unaligned_write_be32(&duid->llt.time, time_from_2000y);
+        memcpy(duid->llt.haddr, addr, addr_len);
+
+        *len = sizeof(duid->type) + sizeof(duid->llt.htype) + sizeof(duid->llt.time) + addr_len;
+
+        return 0;
+}
+
+int dhcp_identifier_set_duid_ll(struct duid *duid, const uint8_t *addr, size_t addr_len, uint16_t arp_type, size_t *len) {
+        assert(duid);
+        assert(len);
+        assert(addr);
+
+        if (arp_type == ARPHRD_ETHER)
+                assert_return(addr_len == ETH_ALEN, -EINVAL);
+        else if (arp_type == ARPHRD_INFINIBAND)
+                assert_return(addr_len == INFINIBAND_ALEN, -EINVAL);
+        else
+                return -EINVAL;
+
+        unaligned_write_be16(&duid->type, DUID_TYPE_LL);
+        unaligned_write_be16(&duid->ll.htype, arp_type);
+        memcpy(duid->ll.haddr, addr, addr_len);
+
+        *len = sizeof(duid->type) + sizeof(duid->ll.htype) + addr_len;
+
+        return 0;
+}
+
+int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) {
+        sd_id128_t machine_id;
+        uint64_t hash;
+        int r;
+
+        assert(duid);
+        assert(len);
+
+        r = sd_id128_get_machine(&machine_id);
+        if (r < 0) {
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+                machine_id = SD_ID128_MAKE(01, 02, 03, 04, 05, 06, 07, 08, 09, 0a, 0b, 0c, 0d, 0e, 0f, 10);
+#else
+                return r;
+#endif
+        }
+
+        unaligned_write_be16(&duid->type, DUID_TYPE_EN);
+        unaligned_write_be32(&duid->en.pen, SYSTEMD_PEN);
+
+        *len = sizeof(duid->type) + sizeof(duid->en);
+
+        /* a bit of snake-oil perhaps, but no need to expose the machine-id
+         * directly; duid->en.id might not be aligned, so we need to copy */
+        hash = htole64(siphash24(&machine_id, sizeof(machine_id), HASH_KEY.bytes));
+        memcpy(duid->en.id, &hash, sizeof(duid->en.id));
+
+        return 0;
+}
+
+int dhcp_identifier_set_duid_uuid(struct duid *duid, size_t *len) {
+        sd_id128_t machine_id;
+        int r;
+
+        assert(duid);
+        assert(len);
+
+        r = sd_id128_get_machine_app_specific(APPLICATION_ID, &machine_id);
+        if (r < 0)
+                return r;
+
+        unaligned_write_be16(&duid->type, DUID_TYPE_UUID);
+        memcpy(&duid->raw.data, &machine_id, sizeof(machine_id));
+
+        *len = sizeof(duid->type) + sizeof(machine_id);
+
+        return 0;
+}
+
+int dhcp_identifier_set_iaid(
+                int ifindex,
+                const uint8_t *mac,
+                size_t mac_len,
+                bool legacy_unstable_byteorder,
+                void *_id) {
+        /* name is a pointer to memory in the sd_device struct, so must
+         * have the same scope */
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        const char *name = NULL;
+        uint64_t id;
+        uint32_t id32;
+
+        if (detect_container() <= 0) {
+                /* not in a container, udev will be around */
+                char ifindex_str[1 + DECIMAL_STR_MAX(int)];
+                int r;
+
+                xsprintf(ifindex_str, "n%d", ifindex);
+                if (sd_device_new_from_device_id(&device, ifindex_str) >= 0) {
+                        r = sd_device_get_is_initialized(device);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                /* not yet ready */
+                                return -EBUSY;
+
+                        r = device_is_renaming(device);
+                        if (r < 0)
+                                return r;
+                        if (r > 0)
+                                /* device is under renaming */
+                                return -EBUSY;
+
+                        name = net_get_name_persistent(device);
+                }
+        }
+
+        if (name)
+                id = siphash24(name, strlen(name), HASH_KEY.bytes);
+        else
+                /* fall back to MAC address if no predictable name available */
+                id = siphash24(mac, mac_len, HASH_KEY.bytes);
+
+        id32 = (id & 0xffffffff) ^ (id >> 32);
+
+        if (legacy_unstable_byteorder)
+                /* for historical reasons (a bug), the bits were swapped and thus
+                 * the result was endianness dependent. Preserve that behavior. */
+                id32 = __bswap_32(id32);
+        else
+                /* the fixed behavior returns a stable byte order. Since LE is expected
+                 * to be more common, swap the bytes on LE to give the same as legacy
+                 * behavior. */
+                id32 = be32toh(id32);
+
+        unaligned_write_ne32(_id, id32);
+        return 0;
+}
diff --git a/src/libsystemd-network/dhcp-identifier.h b/src/libsystemd-network/dhcp-identifier.h
new file mode 100644
index 0000000..e9f2ea7
--- /dev/null
+++ b/src/libsystemd-network/dhcp-identifier.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-id128.h"
+
+#include "macro.h"
+#include "sparse-endian.h"
+#include "time-util.h"
+#include "unaligned.h"
+
+#define SYSTEMD_PEN    43793
+
+typedef enum DUIDType {
+        DUID_TYPE_LLT       = 1,
+        DUID_TYPE_EN        = 2,
+        DUID_TYPE_LL        = 3,
+        DUID_TYPE_UUID      = 4,
+        _DUID_TYPE_MAX,
+        _DUID_TYPE_INVALID  = -1,
+} DUIDType;
+
+/* RFC 3315 section 9.1:
+ *      A DUID can be no more than 128 octets long (not including the type code).
+ */
+#define MAX_DUID_LEN 128
+
+/* https://tools.ietf.org/html/rfc3315#section-9.1 */
+struct duid {
+        be16_t type;
+        union {
+                struct {
+                        /* DUID_TYPE_LLT */
+                        be16_t htype;
+                        be32_t time;
+                        uint8_t haddr[0];
+                } _packed_ llt;
+                struct {
+                        /* DUID_TYPE_EN */
+                        be32_t pen;
+                        uint8_t id[8];
+                } _packed_ en;
+                struct {
+                        /* DUID_TYPE_LL */
+                        be16_t htype;
+                        uint8_t haddr[0];
+                } _packed_ ll;
+                struct {
+                        /* DUID_TYPE_UUID */
+                        sd_id128_t uuid;
+                } _packed_ uuid;
+                struct {
+                        uint8_t data[MAX_DUID_LEN];
+                } _packed_ raw;
+        };
+} _packed_;
+
+int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len, bool strict);
+int dhcp_identifier_set_duid_llt(struct duid *duid, usec_t t, const uint8_t *addr, size_t addr_len, uint16_t arp_type, size_t *len);
+int dhcp_identifier_set_duid_ll(struct duid *duid, const uint8_t *addr, size_t addr_len, uint16_t arp_type, size_t *len);
+int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len);
+int dhcp_identifier_set_duid_uuid(struct duid *duid, size_t *len);
+int dhcp_identifier_set_iaid(int ifindex, const uint8_t *mac, size_t mac_len, bool legacy_unstable_byteorder, void *_id);
diff --git a/src/libsystemd-network/dhcp-internal.h b/src/libsystemd-network/dhcp-internal.h
new file mode 100644
index 0000000..40e6b1f
--- /dev/null
+++ b/src/libsystemd-network/dhcp-internal.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <linux/if_packet.h>
+#include <net/ethernet.h>
+#include <stdint.h>
+
+#include "sd-dhcp-client.h"
+
+#include "dhcp-protocol.h"
+#include "socket-util.h"
+
+typedef struct sd_dhcp_option {
+        unsigned n_ref;
+
+        uint8_t option;
+        void *data;
+        size_t length;
+} sd_dhcp_option;
+
+typedef struct DHCPServerData {
+        struct in_addr *addr;
+        size_t size;
+} DHCPServerData;
+
+extern const struct hash_ops dhcp_option_hash_ops;
+
+int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link, uint32_t xid,
+                                 const uint8_t *mac_addr, size_t mac_addr_len,
+                                 const uint8_t *bcast_addr, size_t bcast_addr_len,
+                                 uint16_t arp_type, uint16_t port);
+int dhcp_network_bind_udp_socket(int ifindex, be32_t address, uint16_t port, int ip_service_type);
+int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
+                                 const void *packet, size_t len);
+int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port,
+                                 const void *packet, size_t len);
+
+int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset, uint8_t overload,
+                       uint8_t code, size_t optlen, const void *optval);
+
+typedef int (*dhcp_option_callback_t)(uint8_t code, uint8_t len,
+                                const void *option, void *userdata);
+
+int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t cb, void *userdata, char **error_message);
+
+int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
+                      uint8_t type, uint16_t arp_type, size_t optlen,
+                      size_t *optoffset);
+
+uint16_t dhcp_packet_checksum(uint8_t *buf, size_t len);
+
+void dhcp_packet_append_ip_headers(DHCPPacket *packet, be32_t source_addr,
+                                   uint16_t source, be32_t destination_addr,
+                                   uint16_t destination, uint16_t len, int ip_service_type);
+
+int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum, uint16_t port);
+
+/* If we are invoking callbacks of a dhcp-client, ensure unreffing the
+ * client from the callback doesn't destroy the object we are working
+ * on */
+#define DHCP_CLIENT_DONT_DESTROY(client) \
+        _cleanup_(sd_dhcp_client_unrefp) _unused_ sd_dhcp_client *_dont_destroy_##client = sd_dhcp_client_ref(client)
+
+#define log_dhcp_client_errno(client, error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "DHCP CLIENT (0x%x): " fmt, client->xid, ##__VA_ARGS__)
+#define log_dhcp_client(client, fmt, ...) log_dhcp_client_errno(client, 0, fmt, ##__VA_ARGS__)
diff --git a/src/libsystemd-network/dhcp-lease-internal.h b/src/libsystemd-network/dhcp-lease-internal.h
new file mode 100644
index 0000000..49392d1
--- /dev/null
+++ b/src/libsystemd-network/dhcp-lease-internal.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include "sd-dhcp-client.h"
+
+#include "dhcp-internal.h"
+#include "dhcp-protocol.h"
+#include "list.h"
+#include "util.h"
+
+struct sd_dhcp_route {
+        struct in_addr dst_addr;
+        struct in_addr gw_addr;
+        unsigned char dst_prefixlen;
+
+        uint8_t option;
+};
+
+struct sd_dhcp_raw_option {
+        LIST_FIELDS(struct sd_dhcp_raw_option, options);
+
+        uint8_t tag;
+        uint8_t length;
+        void *data;
+};
+
+struct sd_dhcp_lease {
+        unsigned n_ref;
+
+        /* each 0 if unset */
+        uint32_t t1;
+        uint32_t t2;
+        uint32_t lifetime;
+
+        /* each 0 if unset */
+        be32_t address;
+        be32_t server_address;
+        be32_t next_server;
+
+        bool have_subnet_mask;
+        be32_t subnet_mask;
+
+        bool have_broadcast;
+        be32_t broadcast;
+
+        struct in_addr *router;
+        size_t router_size;
+
+        DHCPServerData servers[_SD_DHCP_LEASE_SERVER_TYPE_MAX];
+
+        struct sd_dhcp_route *static_route;
+        size_t static_route_size, static_route_allocated;
+
+        uint16_t mtu; /* 0 if unset */
+
+        char *domainname;
+        char **search_domains;
+        char *hostname;
+        char *root_path;
+
+        void *client_id;
+        size_t client_id_len;
+
+        void *vendor_specific;
+        size_t vendor_specific_len;
+
+        char *timezone;
+
+        LIST_HEAD(struct sd_dhcp_raw_option, private_options);
+};
+
+int dhcp_lease_new(sd_dhcp_lease **ret);
+
+int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void *userdata);
+int dhcp_lease_parse_search_domains(const uint8_t *option, size_t len, char ***domains);
+int dhcp_lease_insert_private_option(sd_dhcp_lease *lease, uint8_t tag, const void *data, uint8_t len);
+
+int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease);
+
+int dhcp_lease_set_client_id(sd_dhcp_lease *lease, const void *client_id, size_t client_id_len);
diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c
new file mode 100644
index 0000000..656482b
--- /dev/null
+++ b/src/libsystemd-network/dhcp-network.c
@@ -0,0 +1,244 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <stdio.h>
+#include <string.h>
+#include <linux/filter.h>
+#include <linux/if_infiniband.h>
+#include <linux/if_packet.h>
+
+#include "dhcp-internal.h"
+#include "fd-util.h"
+#include "socket-util.h"
+#include "unaligned.h"
+
+static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
+                            uint32_t xid,
+                            const uint8_t *bcast_addr,
+                            size_t bcast_addr_len,
+                            const struct ether_addr *eth_mac,
+                            uint16_t arp_type, uint8_t dhcp_hlen,
+                            uint16_t port) {
+        struct sock_filter filter[] = {
+                BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0),                                 /* A <- packet length */
+                BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0),         /* packet >= DHCPPacket ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0),                /* IP protocol == UDP ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */
+                BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20),                             /* A <- A & 0x20 (More Fragments bit) */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0),                          /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */
+                BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff),                           /* A <- A & 0x1fff (Fragment offset) */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0),                          /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)),    /* A <- UDP destination port */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, port, 1, 0),                       /* UDP destination port == DHCP client port ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)),     /* A <- DHCP op */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0),                  /* op == BOOTREPLY ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)),  /* A <- DHCP header type */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, arp_type, 1, 0),                   /* header type == arp_type ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)),    /* A <- client identifier */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0),                        /* client identifier == xid ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)),   /* A <- MAC address length */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, dhcp_hlen, 1, 0),                  /* address length == dhcp_hlen ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+
+                /* We only support MAC address length to be either 0 or 6 (ETH_ALEN). Optionally
+                 * compare chaddr for ETH_ALEN bytes. */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETH_ALEN, 0, 12),                                  /* A (the MAC address length) == ETH_ALEN ? */
+                BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be32(&eth_mac->ether_addr_octet[0])),        /* A <- 4 bytes of client's MAC */
+                BPF_STMT(BPF_MISC + BPF_TAX, 0),                                                       /* X <- A */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)),                 /* A <- 4 bytes of MAC from dhcp.chaddr */
+                BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0),                                                /* A xor X */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0),                                          /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                          /* ignore */
+                BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be16(&eth_mac->ether_addr_octet[4])),        /* A <- remainder of client's MAC */
+                BPF_STMT(BPF_MISC + BPF_TAX, 0),                                                       /* X <- A */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4),             /* A <- remainder of MAC from dhcp.chaddr */
+                BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0),                                                /* A xor X */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0),                                          /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                          /* ignore */
+
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)),  /* A <- DHCP magic cookie */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0),          /* cookie == DHCP magic cookie ? */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                          /* ignore */
+                BPF_STMT(BPF_RET + BPF_K, 65535),                                      /* return all */
+        };
+        struct sock_fprog fprog = {
+                .len = ELEMENTSOF(filter),
+                .filter = filter
+        };
+        _cleanup_close_ int s = -1;
+        int r;
+
+        assert(ifindex > 0);
+        assert(link);
+
+        s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (s < 0)
+                return -errno;
+
+        r = setsockopt_int(s, SOL_PACKET, PACKET_AUXDATA, true);
+        if (r < 0)
+                return r;
+
+        r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
+        if (r < 0)
+                return -errno;
+
+        link->ll = (struct sockaddr_ll) {
+                .sll_family = AF_PACKET,
+                .sll_protocol = htobe16(ETH_P_IP),
+                .sll_ifindex = ifindex,
+                .sll_hatype = htobe16(arp_type),
+                .sll_halen = bcast_addr_len,
+        };
+        memcpy(link->ll.sll_addr, bcast_addr, bcast_addr_len); /* We may overflow link->ll. link->ll_buffer ensures we have enough space. */
+
+        r = bind(s, &link->sa, SOCKADDR_LL_LEN(link->ll));
+        if (r < 0)
+                return -errno;
+
+        return TAKE_FD(s);
+}
+
+int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link, uint32_t xid,
+                                 const uint8_t *mac_addr, size_t mac_addr_len,
+                                 const uint8_t *bcast_addr, size_t bcast_addr_len,
+                                 uint16_t arp_type, uint16_t port) {
+        static const uint8_t eth_bcast[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+        /* Default broadcast address for IPoIB */
+        static const uint8_t ib_bcast[] = {
+                0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0xff, 0xff, 0xff, 0xff
+        };
+        struct ether_addr eth_mac = { { 0, 0, 0, 0, 0, 0 } };
+        const uint8_t *default_bcast_addr;
+        size_t expected_bcast_addr_len;
+        uint8_t dhcp_hlen = 0;
+
+        if (arp_type == ARPHRD_ETHER) {
+                assert_return(mac_addr_len == ETH_ALEN, -EINVAL);
+                memcpy(&eth_mac, mac_addr, ETH_ALEN);
+                dhcp_hlen = ETH_ALEN;
+
+                default_bcast_addr = eth_bcast;
+                expected_bcast_addr_len = ETH_ALEN;
+        } else if (arp_type == ARPHRD_INFINIBAND) {
+                default_bcast_addr = ib_bcast;
+                expected_bcast_addr_len = INFINIBAND_ALEN;
+        } else
+                return -EINVAL;
+
+        if (bcast_addr && bcast_addr_len > 0)
+                assert_return(bcast_addr_len == expected_bcast_addr_len, -EINVAL);
+        else {
+                bcast_addr = default_bcast_addr;
+                bcast_addr_len = expected_bcast_addr_len;
+        }
+
+        return _bind_raw_socket(ifindex, link, xid, bcast_addr, bcast_addr_len,
+                                &eth_mac, arp_type, dhcp_hlen, port);
+}
+
+int dhcp_network_bind_udp_socket(int ifindex, be32_t address, uint16_t port, int ip_service_type) {
+        union sockaddr_union src = {
+                .in.sin_family = AF_INET,
+                .in.sin_port = htobe16(port),
+                .in.sin_addr.s_addr = address,
+        };
+        _cleanup_close_ int s = -1;
+        int r;
+
+        s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (s < 0)
+                return -errno;
+
+        if (ip_service_type >= 0)
+                r = setsockopt_int(s, IPPROTO_IP, IP_TOS, ip_service_type);
+        else
+                r = setsockopt_int(s, IPPROTO_IP, IP_TOS, IPTOS_CLASS_CS6);
+
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+        if (r < 0)
+                return r;
+
+        if (ifindex > 0) {
+                r = socket_bind_to_ifindex(s, ifindex);
+                if (r < 0)
+                        return r;
+        }
+
+        if (address == INADDR_ANY) {
+                r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
+                if (r < 0)
+                        return r;
+
+                r = setsockopt_int(s, SOL_SOCKET, SO_BROADCAST, true);
+                if (r < 0)
+                        return r;
+
+        } else {
+                r = setsockopt_int(s, IPPROTO_IP, IP_FREEBIND, true);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bind(s, &src.sa, sizeof(src.in));
+        if (r < 0)
+                return -errno;
+
+        return TAKE_FD(s);
+}
+
+int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
+                                 const void *packet, size_t len) {
+        int r;
+
+        assert(link);
+        assert(packet);
+        assert(len);
+
+        r = sendto(s, packet, len, 0, &link->sa, SOCKADDR_LL_LEN(link->ll));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port,
+                                 const void *packet, size_t len) {
+        union sockaddr_union dest = {
+                .in.sin_family = AF_INET,
+                .in.sin_port = htobe16(port),
+                .in.sin_addr.s_addr = address,
+        };
+        int r;
+
+        assert(s >= 0);
+        assert(packet);
+        assert(len);
+
+        r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c
new file mode 100644
index 0000000..7e3fe43
--- /dev/null
+++ b/src/libsystemd-network/dhcp-option.c
@@ -0,0 +1,358 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include "alloc-util.h"
+#include "dhcp-internal.h"
+#include "dhcp-server-internal.h"
+#include "memory-util.h"
+#include "strv.h"
+#include "utf8.h"
+
+static int option_append(uint8_t options[], size_t size, size_t *offset,
+                         uint8_t code, size_t optlen, const void *optval) {
+        assert(options);
+        assert(offset);
+
+        if (code != SD_DHCP_OPTION_END)
+                /* always make sure there is space for an END option */
+                size--;
+
+        switch (code) {
+
+        case SD_DHCP_OPTION_PAD:
+        case SD_DHCP_OPTION_END:
+                if (*offset + 1 > size)
+                        return -ENOBUFS;
+
+                options[*offset] = code;
+                *offset += 1;
+                break;
+
+        case SD_DHCP_OPTION_USER_CLASS: {
+                size_t total = 0;
+                char **s;
+
+                if (strv_isempty((char **) optval))
+                        return -EINVAL;
+
+                STRV_FOREACH(s, (char **) optval) {
+                        size_t len = strlen(*s);
+
+                        if (len > 255 || len == 0)
+                                return -EINVAL;
+
+                        total += 1 + len;
+                }
+
+                if (*offset + 2 + total > size)
+                        return -ENOBUFS;
+
+                options[*offset] = code;
+                options[*offset + 1] = total;
+                *offset += 2;
+
+                STRV_FOREACH(s, (char **) optval) {
+                        size_t len = strlen(*s);
+
+                        options[*offset] = len;
+                        memcpy(&options[*offset + 1], *s, len);
+                        *offset += 1 + len;
+                }
+
+                break;
+        }
+        case SD_DHCP_OPTION_SIP_SERVER:
+                if (*offset + 3 + optlen > size)
+                        return -ENOBUFS;
+
+                options[*offset] = code;
+                options[*offset + 1] = optlen + 1;
+                options[*offset + 2] = 1;
+
+                memcpy_safe(&options[*offset + 3], optval, optlen);
+                *offset += 3 + optlen;
+
+                break;
+        case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
+                OrderedHashmap *s = (OrderedHashmap *) optval;
+                struct sd_dhcp_option *p;
+                size_t l = 0;
+
+                ORDERED_HASHMAP_FOREACH(p, s)
+                        l += p->length + 2;
+
+                if (*offset + l + 2 > size)
+                        return -ENOBUFS;
+
+                options[*offset] = code;
+                options[*offset + 1] = l;
+
+                *offset += 2;
+
+                ORDERED_HASHMAP_FOREACH(p, s) {
+                        options[*offset] = p->option;
+                        options[*offset + 1] = p->length;
+                        memcpy(&options[*offset + 2], p->data, p->length);
+                        *offset += 2 + p->length;
+                }
+
+                break;
+        }
+        default:
+                if (*offset + 2 + optlen > size)
+                        return -ENOBUFS;
+
+                options[*offset] = code;
+                options[*offset + 1] = optlen;
+
+                memcpy_safe(&options[*offset + 2], optval, optlen);
+                *offset += 2 + optlen;
+
+                break;
+        }
+
+        return 0;
+}
+
+int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset,
+                       uint8_t overload,
+                       uint8_t code, size_t optlen, const void *optval) {
+        const bool use_file = overload & DHCP_OVERLOAD_FILE;
+        const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
+        int r;
+
+        assert(message);
+        assert(offset);
+
+        /* If *offset is in range [0, size), we are writing to ->options,
+         * if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
+         * if *offset is in range [size + use_file*sizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
+         * and use_sname, we are writing to ->sname.
+         */
+
+        if (*offset < size) {
+                /* still space in the options array */
+                r = option_append(message->options, size, offset, code, optlen, optval);
+                if (r >= 0)
+                        return 0;
+                else if (r == -ENOBUFS && (use_file || use_sname)) {
+                        /* did not fit, but we have more buffers to try
+                           close the options array and move the offset to its end */
+                        r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        *offset = size;
+                } else
+                        return r;
+        }
+
+        if (use_file) {
+                size_t file_offset = *offset - size;
+
+                if (file_offset < sizeof(message->file)) {
+                        /* still space in the 'file' array */
+                        r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
+                        if (r >= 0) {
+                                *offset = size + file_offset;
+                                return 0;
+                        } else if (r == -ENOBUFS && use_sname) {
+                                /* did not fit, but we have more buffers to try
+                                   close the file array and move the offset to its end */
+                                r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
+                                if (r < 0)
+                                        return r;
+
+                                *offset = size + sizeof(message->file);
+                        } else
+                                return r;
+                }
+        }
+
+        if (use_sname) {
+                size_t sname_offset = *offset - size - use_file*sizeof(message->file);
+
+                if (sname_offset < sizeof(message->sname)) {
+                        /* still space in the 'sname' array */
+                        r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
+                        if (r >= 0) {
+                                *offset = size + use_file*sizeof(message->file) + sname_offset;
+                                return 0;
+                        } else
+                                /* no space, or other error, give up */
+                                return r;
+                }
+        }
+
+        return -ENOBUFS;
+}
+
+static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
+                         uint8_t *message_type, char **error_message, dhcp_option_callback_t cb,
+                         void *userdata) {
+        uint8_t code, len;
+        const uint8_t *option;
+        size_t offset = 0;
+
+        while (offset < buflen) {
+                code = options[offset ++];
+
+                switch (code) {
+                case SD_DHCP_OPTION_PAD:
+                        continue;
+
+                case SD_DHCP_OPTION_END:
+                        return 0;
+                }
+
+                if (buflen < offset + 1)
+                        return -ENOBUFS;
+
+                len = options[offset ++];
+
+                if (buflen < offset + len)
+                        return -EINVAL;
+
+                option = &options[offset];
+
+                switch (code) {
+                case SD_DHCP_OPTION_MESSAGE_TYPE:
+                        if (len != 1)
+                                return -EINVAL;
+
+                        if (message_type)
+                                *message_type = *option;
+
+                        break;
+
+                case SD_DHCP_OPTION_ERROR_MESSAGE:
+                        if (len == 0)
+                                return -EINVAL;
+
+                        if (error_message) {
+                                _cleanup_free_ char *string = NULL;
+
+                                /* Accept a trailing NUL byte */
+                                if (memchr(option, 0, len - 1))
+                                        return -EINVAL;
+
+                                string = memdup_suffix0((const char *) option, len);
+                                if (!string)
+                                        return -ENOMEM;
+
+                                if (!ascii_is_valid(string))
+                                        return -EINVAL;
+
+                                free_and_replace(*error_message, string);
+                        }
+
+                        break;
+                case SD_DHCP_OPTION_OVERLOAD:
+                        if (len != 1)
+                                return -EINVAL;
+
+                        if (overload)
+                                *overload = *option;
+
+                        break;
+
+                default:
+                        if (cb)
+                                cb(code, len, option, userdata);
+
+                        break;
+                }
+
+                offset += len;
+        }
+
+        if (offset < buflen)
+                return -EINVAL;
+
+        return 0;
+}
+
+int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t cb, void *userdata, char **_error_message) {
+        _cleanup_free_ char *error_message = NULL;
+        uint8_t overload = 0;
+        uint8_t message_type = 0;
+        int r;
+
+        if (!message)
+                return -EINVAL;
+
+        if (len < sizeof(DHCPMessage))
+                return -EINVAL;
+
+        len -= sizeof(DHCPMessage);
+
+        r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
+        if (r < 0)
+                return r;
+
+        if (overload & DHCP_OVERLOAD_FILE) {
+                r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
+                if (r < 0)
+                        return r;
+        }
+
+        if (overload & DHCP_OVERLOAD_SNAME) {
+                r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
+                if (r < 0)
+                        return r;
+        }
+
+        if (message_type == 0)
+                return -ENOMSG;
+
+        if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
+                *_error_message = TAKE_PTR(error_message);
+
+        return message_type;
+}
+
+static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
+        if (!i)
+                return NULL;
+
+        free(i->data);
+        return mfree(i);
+}
+
+int sd_dhcp_option_new(uint8_t option, const void *data, size_t length, sd_dhcp_option **ret) {
+        assert_return(ret, -EINVAL);
+        assert_return(length == 0 || data, -EINVAL);
+
+        _cleanup_free_ void *q = memdup(data, length);
+        if (!q)
+                return -ENOMEM;
+
+        sd_dhcp_option *p = new(sd_dhcp_option, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (sd_dhcp_option) {
+                .n_ref = 1,
+                .option = option,
+                .length = length,
+                .data = TAKE_PTR(q),
+        };
+
+        *ret = TAKE_PTR(p);
+        return 0;
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
+DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
+                dhcp_option_hash_ops,
+                void,
+                trivial_hash_func,
+                trivial_compare_func,
+                sd_dhcp_option,
+                sd_dhcp_option_unref);
diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c
new file mode 100644
index 0000000..cace916
--- /dev/null
+++ b/src/libsystemd-network/dhcp-packet.c
@@ -0,0 +1,171 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <net/ethernet.h>
+#include <net/if_arp.h>
+#include <string.h>
+
+#include "dhcp-internal.h"
+#include "dhcp-protocol.h"
+
+#define DHCP_CLIENT_MIN_OPTIONS_SIZE            312
+
+int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
+                      uint8_t type, uint16_t arp_type, size_t optlen,
+                      size_t *optoffset) {
+        size_t offset = 0;
+        int r;
+
+        assert(IN_SET(op, BOOTREQUEST, BOOTREPLY));
+        assert(IN_SET(arp_type, ARPHRD_ETHER, ARPHRD_INFINIBAND));
+
+        message->op = op;
+        message->htype = arp_type;
+        message->hlen = (arp_type == ARPHRD_ETHER) ? ETHER_ADDR_LEN : 0;
+        message->xid = htobe32(xid);
+        message->magic = htobe32(DHCP_MAGIC_COOKIE);
+
+        r = dhcp_option_append(message, optlen, &offset, 0,
+                               SD_DHCP_OPTION_MESSAGE_TYPE, 1, &type);
+        if (r < 0)
+                return r;
+
+        *optoffset = offset;
+
+        return 0;
+}
+
+uint16_t dhcp_packet_checksum(uint8_t *buf, size_t len) {
+        uint64_t *buf_64 = (uint64_t*)buf;
+        uint64_t *end_64 = buf_64 + (len / sizeof(uint64_t));
+        uint64_t sum = 0;
+
+        /* See RFC1071 */
+
+        while (buf_64 < end_64) {
+                sum += *buf_64;
+                if (sum < *buf_64)
+                        /* wrap around in one's complement */
+                        sum++;
+
+                buf_64++;
+        }
+
+        if (len % sizeof(uint64_t)) {
+                /* If the buffer is not aligned to 64-bit, we need
+                   to zero-pad the last few bytes and add them in */
+                uint64_t buf_tail = 0;
+
+                memcpy(&buf_tail, buf_64, len % sizeof(uint64_t));
+
+                sum += buf_tail;
+                if (sum < buf_tail)
+                        /* wrap around */
+                        sum++;
+        }
+
+        while (sum >> 16)
+                sum = (sum & 0xffff) + (sum >> 16);
+
+        return ~sum;
+}
+
+void dhcp_packet_append_ip_headers(DHCPPacket *packet, be32_t source_addr,
+                                   uint16_t source_port, be32_t destination_addr,
+                                   uint16_t destination_port, uint16_t len, int ip_service_type) {
+        packet->ip.version = IPVERSION;
+        packet->ip.ihl = DHCP_IP_SIZE / 4;
+        packet->ip.tot_len = htobe16(len);
+
+        if (ip_service_type >= 0)
+                packet->ip.tos = ip_service_type;
+        else
+                packet->ip.tos = IPTOS_CLASS_CS6;
+
+        packet->ip.protocol = IPPROTO_UDP;
+        packet->ip.saddr = source_addr;
+        packet->ip.daddr = destination_addr;
+
+        packet->udp.source = htobe16(source_port);
+        packet->udp.dest = htobe16(destination_port);
+
+        packet->udp.len = htobe16(len - DHCP_IP_SIZE);
+
+        packet->ip.check = packet->udp.len;
+        packet->udp.check = dhcp_packet_checksum((uint8_t*)&packet->ip.ttl, len - 8);
+
+        packet->ip.ttl = IPDEFTTL;
+        packet->ip.check = 0;
+        packet->ip.check = dhcp_packet_checksum((uint8_t*)&packet->ip, DHCP_IP_SIZE);
+}
+
+int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum, uint16_t port) {
+        size_t hdrlen;
+
+        assert(packet);
+
+        /* IP */
+
+        if (packet->ip.version != IPVERSION)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: not IPv4");
+
+        if (packet->ip.ihl < 5)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: IPv4 IHL (%u words) invalid",
+                                       packet->ip.ihl);
+
+        hdrlen = packet->ip.ihl * 4;
+        if (hdrlen < 20)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: IPv4 IHL (%zu bytes) "
+                                       "smaller than minimum (20 bytes)",
+                                       hdrlen);
+
+        if (len < hdrlen)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: packet (%zu bytes) "
+                                       "smaller than expected (%zu) by IP header",
+                                       len, hdrlen);
+
+        /* UDP */
+
+        if (packet->ip.protocol != IPPROTO_UDP)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: not UDP");
+
+        if (len < hdrlen + be16toh(packet->udp.len))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: packet (%zu bytes) "
+                                       "smaller than expected (%zu) by UDP header",
+                                       len, hdrlen + be16toh(packet->udp.len));
+
+        if (be16toh(packet->udp.dest) != port)
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: to port %u, which "
+                                       "is not the DHCP client port (%u)",
+                                       be16toh(packet->udp.dest), port);
+
+        /* checksums - computing these is relatively expensive, so only do it
+           if all the other checks have passed
+         */
+
+        if (dhcp_packet_checksum((uint8_t*)&packet->ip, hdrlen))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "ignoring packet: invalid IP checksum");
+
+        if (checksum && packet->udp.check) {
+                packet->ip.check = packet->udp.len;
+                packet->ip.ttl = 0;
+
+                if (dhcp_packet_checksum((uint8_t*)&packet->ip.ttl,
+                                  be16toh(packet->udp.len) + 12))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "ignoring packet: invalid UDP checksum");
+        }
+
+        return 0;
+}
diff --git a/src/libsystemd-network/dhcp-protocol.h b/src/libsystemd-network/dhcp-protocol.h
new file mode 100644
index 0000000..11f4201
--- /dev/null
+++ b/src/libsystemd-network/dhcp-protocol.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+#include <stdint.h>
+
+#include "macro.h"
+#include "sparse-endian.h"
+
+struct DHCPMessage {
+        uint8_t op;
+        uint8_t htype;
+        uint8_t hlen;
+        uint8_t hops;
+        be32_t xid;
+        be16_t secs;
+        be16_t flags;
+        be32_t ciaddr;
+        be32_t yiaddr;
+        be32_t siaddr;
+        be32_t giaddr;
+        uint8_t chaddr[16];
+        uint8_t sname[64];
+        uint8_t file[128];
+        be32_t magic;
+        uint8_t options[0];
+} _packed_;
+
+typedef struct DHCPMessage DHCPMessage;
+
+struct DHCPPacket {
+        struct iphdr ip;
+        struct udphdr udp;
+        DHCPMessage dhcp;
+} _packed_;
+
+typedef struct DHCPPacket DHCPPacket;
+
+#define DHCP_IP_SIZE            (int32_t)(sizeof(struct iphdr))
+#define DHCP_IP_UDP_SIZE        (int32_t)(sizeof(struct udphdr) + DHCP_IP_SIZE)
+#define DHCP_MESSAGE_SIZE       (int32_t)(sizeof(DHCPMessage))
+#define DHCP_DEFAULT_MIN_SIZE   576 /* the minimum internet hosts must be able to receive */
+#define DHCP_MIN_OPTIONS_SIZE   (DHCP_DEFAULT_MIN_SIZE - DHCP_IP_UDP_SIZE - DHCP_MESSAGE_SIZE)
+#define DHCP_MAGIC_COOKIE       (uint32_t)(0x63825363)
+
+enum {
+        DHCP_PORT_SERVER                        = 67,
+        DHCP_PORT_CLIENT                        = 68,
+};
+
+enum DHCPState {
+        DHCP_STATE_INIT                         = 0,
+        DHCP_STATE_SELECTING                    = 1,
+        DHCP_STATE_INIT_REBOOT                  = 2,
+        DHCP_STATE_REBOOTING                    = 3,
+        DHCP_STATE_REQUESTING                   = 4,
+        DHCP_STATE_BOUND                        = 5,
+        DHCP_STATE_RENEWING                     = 6,
+        DHCP_STATE_REBINDING                    = 7,
+        DHCP_STATE_STOPPED                      = 8,
+};
+
+typedef enum DHCPState DHCPState;
+
+enum {
+        BOOTREQUEST                             = 1,
+        BOOTREPLY                               = 2,
+};
+
+enum {
+        DHCP_DISCOVER                           = 1,
+        DHCP_OFFER                              = 2,
+        DHCP_REQUEST                            = 3,
+        DHCP_DECLINE                            = 4,
+        DHCP_ACK                                = 5,
+        DHCP_NAK                                = 6,
+        DHCP_RELEASE                            = 7,
+        DHCP_INFORM                             = 8,
+        DHCP_FORCERENEW                         = 9,
+};
+
+enum {
+        DHCP_OVERLOAD_FILE                      = 1,
+        DHCP_OVERLOAD_SNAME                     = 2,
+};
+
+#define DHCP_MAX_FQDN_LENGTH 255
+
+enum {
+        DHCP_FQDN_FLAG_S = (1 << 0),
+        DHCP_FQDN_FLAG_O = (1 << 1),
+        DHCP_FQDN_FLAG_E = (1 << 2),
+        DHCP_FQDN_FLAG_N = (1 << 3),
+};
diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
new file mode 100644
index 0000000..b57737e
--- /dev/null
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include "sd-dhcp-server.h"
+#include "sd-event.h"
+
+#include "dhcp-internal.h"
+#include "hashmap.h"
+#include "log.h"
+#include "time-util.h"
+
+typedef enum DHCPRawOption {
+        DHCP_RAW_OPTION_DATA_UINT8,
+        DHCP_RAW_OPTION_DATA_UINT16,
+        DHCP_RAW_OPTION_DATA_UINT32,
+        DHCP_RAW_OPTION_DATA_STRING,
+        DHCP_RAW_OPTION_DATA_IPV4ADDRESS,
+        DHCP_RAW_OPTION_DATA_IPV6ADDRESS,
+        _DHCP_RAW_OPTION_DATA_MAX,
+        _DHCP_RAW_OPTION_DATA_INVALID,
+} DHCPRawOption;
+
+typedef struct DHCPClientId {
+        size_t length;
+        void *data;
+} DHCPClientId;
+
+typedef struct DHCPLease {
+        DHCPClientId client_id;
+
+        be32_t address;
+        be32_t gateway;
+        uint8_t chaddr[16];
+        usec_t expiration;
+} DHCPLease;
+
+struct sd_dhcp_server {
+        unsigned n_ref;
+
+        sd_event *event;
+        int event_priority;
+        sd_event_source *receive_message;
+        int fd;
+        int fd_raw;
+
+        int ifindex;
+        be32_t address;
+        be32_t netmask;
+        be32_t subnet;
+        uint32_t pool_offset;
+        uint32_t pool_size;
+
+        char *timezone;
+
+        DHCPServerData servers[_SD_DHCP_LEASE_SERVER_TYPE_MAX];
+
+        OrderedHashmap *extra_options;
+        OrderedHashmap *vendor_options;
+
+        bool emit_router;
+
+        Hashmap *leases_by_client_id;
+        DHCPLease **bound_leases;
+        DHCPLease invalid_lease;
+
+        uint32_t max_lease_time, default_lease_time;
+
+        sd_dhcp_server_callback_t callback;
+        void *callback_userdata;
+};
+
+typedef struct DHCPRequest {
+        /* received message */
+        DHCPMessage *message;
+
+        /* options */
+        DHCPClientId client_id;
+        size_t max_optlen;
+        be32_t server_id;
+        be32_t requested_ip;
+        uint32_t lifetime;
+} DHCPRequest;
+
+#define log_dhcp_server(client, fmt, ...) log_internal(LOG_DEBUG, 0, PROJECT_FILE, __LINE__, __func__, "DHCP SERVER: " fmt, ##__VA_ARGS__)
+#define log_dhcp_server_errno(client, error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "DHCP SERVER: " fmt, ##__VA_ARGS__)
+
+int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
+                               size_t length);
+int dhcp_server_send_packet(sd_dhcp_server *server,
+                            DHCPRequest *req, DHCPPacket *packet,
+                            int type, size_t optoffset);
+
+void client_id_hash_func(const DHCPClientId *p, struct siphash *state);
+int client_id_compare_func(const DHCPClientId *a, const DHCPClientId *b);
diff --git a/src/libsystemd-network/dhcp6-internal.h b/src/libsystemd-network/dhcp6-internal.h
new file mode 100644
index 0000000..9a32b00
--- /dev/null
+++ b/src/libsystemd-network/dhcp6-internal.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014-2015 Intel Corporation. All rights reserved.
+***/
+
+#include <net/ethernet.h>
+#include <netinet/in.h>
+
+#include "sd-event.h"
+
+#include "list.h"
+#include "hashmap.h"
+#include "macro.h"
+#include "sparse-endian.h"
+
+typedef struct sd_dhcp6_option {
+        unsigned n_ref;
+
+        uint32_t enterprise_identifier;
+        uint16_t option;
+        void *data;
+        size_t length;
+} sd_dhcp6_option;
+
+extern const struct hash_ops dhcp6_option_hash_ops;
+
+/* Common option header */
+typedef struct DHCP6Option {
+        be16_t code;
+        be16_t len;
+        uint8_t data[];
+} _packed_ DHCP6Option;
+
+/* Address option */
+struct iaaddr {
+        struct in6_addr address;
+        be32_t lifetime_preferred;
+        be32_t lifetime_valid;
+} _packed_;
+
+/* Prefix Delegation Prefix option */
+struct iapdprefix {
+        be32_t lifetime_preferred;
+        be32_t lifetime_valid;
+        uint8_t prefixlen;
+        struct in6_addr address;
+} _packed_;
+
+typedef struct DHCP6Address DHCP6Address;
+
+struct DHCP6Address {
+        LIST_FIELDS(DHCP6Address, addresses);
+
+        union {
+                struct iaaddr iaaddr;
+                struct iapdprefix iapdprefix;
+        };
+};
+
+/* Non-temporary Address option */
+struct ia_na {
+        be32_t id;
+        be32_t lifetime_t1;
+        be32_t lifetime_t2;
+} _packed_;
+
+/* Prefix Delegation option */
+struct ia_pd {
+        be32_t id;
+        be32_t lifetime_t1;
+        be32_t lifetime_t2;
+} _packed_;
+
+/* Temporary Address option */
+struct ia_ta {
+        be32_t id;
+} _packed_;
+
+struct DHCP6IA {
+        uint16_t type;
+        union {
+                struct ia_na ia_na;
+                struct ia_pd ia_pd;
+                struct ia_ta ia_ta;
+        };
+
+        LIST_HEAD(DHCP6Address, addresses);
+};
+
+typedef struct DHCP6IA DHCP6IA;
+
+#define log_dhcp6_client_errno(p, error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "DHCPv6 CLIENT: " fmt, ##__VA_ARGS__)
+#define log_dhcp6_client(p, fmt, ...) log_dhcp6_client_errno(p, 0, fmt, ##__VA_ARGS__)
+
+int dhcp6_option_append(uint8_t **buf, size_t *buflen, uint16_t code,
+                        size_t optlen, const void *optval);
+int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, const DHCP6IA *ia);
+int dhcp6_option_append_pd(uint8_t *buf, size_t len, const DHCP6IA *pd, DHCP6Address *hint_pd_prefix);
+int dhcp6_option_append_fqdn(uint8_t **buf, size_t *buflen, const char *fqdn);
+int dhcp6_option_append_user_class(uint8_t **buf, size_t *buflen, char * const *user_class);
+int dhcp6_option_append_vendor_class(uint8_t **buf, size_t *buflen, char * const *user_class);
+int dhcp6_option_append_vendor_option(uint8_t **buf, size_t *buflen, OrderedHashmap *vendor_options);
+int dhcp6_option_parse(uint8_t **buf, size_t *buflen, uint16_t *optcode,
+                       size_t *optlen, uint8_t **optvalue);
+int dhcp6_option_parse_status(DHCP6Option *option, size_t len);
+int dhcp6_option_parse_ia(DHCP6Option *iaoption, DHCP6IA *ia, uint16_t *ret_status_code);
+int dhcp6_option_parse_ip6addrs(uint8_t *optval, uint16_t optlen,
+                                struct in6_addr **addrs, size_t count,
+                                size_t *allocated);
+int dhcp6_option_parse_domainname_list(const uint8_t *optval, uint16_t optlen,
+                                       char ***str_arr);
+int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char **str);
+
+int dhcp6_network_bind_udp_socket(int ifindex, struct in6_addr *address);
+int dhcp6_network_send_udp_socket(int s, struct in6_addr *address,
+                                  const void *packet, size_t len);
+
+const char *dhcp6_message_type_to_string(int s) _const_;
+int dhcp6_message_type_from_string(const char *s) _pure_;
+const char *dhcp6_message_status_to_string(int s) _const_;
+int dhcp6_message_status_from_string(const char *s) _pure_;
diff --git a/src/libsystemd-network/dhcp6-lease-internal.h b/src/libsystemd-network/dhcp6-lease-internal.h
new file mode 100644
index 0000000..e9e2362
--- /dev/null
+++ b/src/libsystemd-network/dhcp6-lease-internal.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014-2015 Intel Corporation. All rights reserved.
+***/
+
+#include <stdint.h>
+
+#include "sd-dhcp6-lease.h"
+
+#include "dhcp6-internal.h"
+
+struct sd_dhcp6_lease {
+        unsigned n_ref;
+
+        uint8_t *serverid;
+        size_t serverid_len;
+        uint8_t preference;
+        bool rapid_commit;
+
+        DHCP6IA ia;
+        DHCP6IA pd;
+
+        DHCP6Address *addr_iter;
+        DHCP6Address *prefix_iter;
+
+        struct in6_addr *dns;
+        size_t dns_count;
+        size_t dns_allocated;
+        char **domains;
+        size_t domains_count;
+        struct in6_addr *ntp;
+        size_t ntp_count;
+        size_t ntp_allocated;
+        char **ntp_fqdn;
+        size_t ntp_fqdn_count;
+        char *fqdn;
+};
+
+int dhcp6_lease_ia_rebind_expire(const DHCP6IA *ia, uint32_t *expire);
+DHCP6IA *dhcp6_lease_free_ia(DHCP6IA *ia);
+
+int dhcp6_lease_set_serverid(sd_dhcp6_lease *lease, const uint8_t *id,
+                             size_t len);
+int dhcp6_lease_get_serverid(sd_dhcp6_lease *lease, uint8_t **id, size_t *len);
+int dhcp6_lease_set_preference(sd_dhcp6_lease *lease, uint8_t preference);
+int dhcp6_lease_get_preference(sd_dhcp6_lease *lease, uint8_t *preference);
+int dhcp6_lease_set_rapid_commit(sd_dhcp6_lease *lease);
+int dhcp6_lease_get_rapid_commit(sd_dhcp6_lease *lease, bool *rapid_commit);
+
+int dhcp6_lease_get_iaid(sd_dhcp6_lease *lease, be32_t *iaid);
+int dhcp6_lease_get_pd_iaid(sd_dhcp6_lease *lease, be32_t *iaid);
+
+int dhcp6_lease_set_dns(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen);
+int dhcp6_lease_set_domains(sd_dhcp6_lease *lease, uint8_t *optval,
+                            size_t optlen);
+int dhcp6_lease_set_ntp(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen);
+int dhcp6_lease_set_sntp(sd_dhcp6_lease *lease, uint8_t *optval,
+                         size_t optlen) ;
+int dhcp6_lease_set_fqdn(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
+
+int dhcp6_lease_new(sd_dhcp6_lease **ret);
diff --git a/src/libsystemd-network/dhcp6-network.c b/src/libsystemd-network/dhcp6-network.c
new file mode 100644
index 0000000..4f7bd53
--- /dev/null
+++ b/src/libsystemd-network/dhcp6-network.c
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <netinet/in.h>
+#include <netinet/ip6.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <linux/if_packet.h>
+
+#include "dhcp6-internal.h"
+#include "dhcp6-protocol.h"
+#include "fd-util.h"
+#include "socket-util.h"
+
+int dhcp6_network_bind_udp_socket(int ifindex, struct in6_addr *local_address) {
+        union sockaddr_union src = {
+                .in6.sin6_family = AF_INET6,
+                .in6.sin6_port = htobe16(DHCP6_PORT_CLIENT),
+                .in6.sin6_scope_id = ifindex,
+        };
+        _cleanup_close_ int s = -1;
+        int r;
+
+        assert(ifindex > 0);
+        assert(local_address);
+
+        src.in6.sin6_addr = *local_address;
+
+        s = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_UDP);
+        if (s < 0)
+                return -errno;
+
+        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_V6ONLY, true);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, false);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+        if (r < 0)
+                return r;
+
+        r = bind(s, &src.sa, sizeof(src.in6));
+        if (r < 0)
+                return -errno;
+
+        return TAKE_FD(s);
+}
+
+int dhcp6_network_send_udp_socket(int s, struct in6_addr *server_address,
+                                  const void *packet, size_t len) {
+        union sockaddr_union dest = {
+                .in6.sin6_family = AF_INET6,
+                .in6.sin6_port = htobe16(DHCP6_PORT_SERVER),
+        };
+        int r;
+
+        assert(server_address);
+
+        memcpy(&dest.in6.sin6_addr, server_address, sizeof(dest.in6.sin6_addr));
+
+        r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in6));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
diff --git a/src/libsystemd-network/dhcp6-option.c b/src/libsystemd-network/dhcp6-option.c
new file mode 100644
index 0000000..9f47c1b
--- /dev/null
+++ b/src/libsystemd-network/dhcp6-option.c
@@ -0,0 +1,799 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014-2015 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <netinet/in.h>
+
+#include "sd-dhcp6-client.h"
+
+#include "alloc-util.h"
+#include "dhcp-identifier.h"
+#include "dhcp6-internal.h"
+#include "dhcp6-lease-internal.h"
+#include "dhcp6-protocol.h"
+#include "dns-domain.h"
+#include "memory-util.h"
+#include "sparse-endian.h"
+#include "strv.h"
+#include "unaligned.h"
+
+typedef struct DHCP6StatusOption {
+        struct DHCP6Option option;
+        be16_t status;
+        char msg[];
+} _packed_ DHCP6StatusOption;
+
+typedef struct DHCP6AddressOption {
+        struct DHCP6Option option;
+        struct iaaddr iaaddr;
+        uint8_t options[];
+} _packed_ DHCP6AddressOption;
+
+typedef struct DHCP6PDPrefixOption {
+        struct DHCP6Option option;
+        struct iapdprefix iapdprefix;
+        uint8_t options[];
+} _packed_ DHCP6PDPrefixOption;
+
+#define DHCP6_OPTION_IA_NA_LEN (sizeof(struct ia_na))
+#define DHCP6_OPTION_IA_PD_LEN (sizeof(struct ia_pd))
+#define DHCP6_OPTION_IA_TA_LEN (sizeof(struct ia_ta))
+
+static int option_append_hdr(uint8_t **buf, size_t *buflen, uint16_t optcode,
+                             size_t optlen) {
+        DHCP6Option *option = (DHCP6Option*) *buf;
+
+        assert_return(buf, -EINVAL);
+        assert_return(*buf, -EINVAL);
+        assert_return(buflen, -EINVAL);
+
+        if (optlen > 0xffff || *buflen < optlen + offsetof(DHCP6Option, data))
+                return -ENOBUFS;
+
+        option->code = htobe16(optcode);
+        option->len = htobe16(optlen);
+
+        *buf += offsetof(DHCP6Option, data);
+        *buflen -= offsetof(DHCP6Option, data);
+
+        return 0;
+}
+
+int dhcp6_option_append(uint8_t **buf, size_t *buflen, uint16_t code,
+                        size_t optlen, const void *optval) {
+        int r;
+
+        assert_return(optval || optlen == 0, -EINVAL);
+
+        r = option_append_hdr(buf, buflen, code, optlen);
+        if (r < 0)
+                return r;
+
+        memcpy_safe(*buf, optval, optlen);
+
+        *buf += optlen;
+        *buflen -= optlen;
+
+        return 0;
+}
+
+int dhcp6_option_append_vendor_option(uint8_t **buf, size_t *buflen, OrderedHashmap *vendor_options) {
+        sd_dhcp6_option *options;
+        int r;
+
+        assert(buf);
+        assert(*buf);
+        assert(buflen);
+        assert(vendor_options);
+
+        ORDERED_HASHMAP_FOREACH(options, vendor_options) {
+                _cleanup_free_ uint8_t *p = NULL;
+                size_t total;
+
+                total = 4 + 2 + 2 + options->length;
+
+                p = malloc(total);
+                if (!p)
+                        return -ENOMEM;
+
+                unaligned_write_be32(p, options->enterprise_identifier);
+                unaligned_write_be16(p + 4, options->option);
+                unaligned_write_be16(p + 6, options->length);
+                memcpy(p + 8, options->data, options->length);
+
+                r = dhcp6_option_append(buf, buflen, SD_DHCP6_OPTION_VENDOR_OPTS, total, p);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, const DHCP6IA *ia) {
+        uint16_t len;
+        uint8_t *ia_hdr;
+        size_t iaid_offset, ia_buflen, ia_addrlen = 0;
+        DHCP6Address *addr;
+        int r;
+
+        assert_return(buf, -EINVAL);
+        assert_return(*buf, -EINVAL);
+        assert_return(buflen, -EINVAL);
+        assert_return(ia, -EINVAL);
+
+        switch (ia->type) {
+        case SD_DHCP6_OPTION_IA_NA:
+                len = DHCP6_OPTION_IA_NA_LEN;
+                iaid_offset = offsetof(DHCP6IA, ia_na);
+                break;
+
+        case SD_DHCP6_OPTION_IA_TA:
+                len = DHCP6_OPTION_IA_TA_LEN;
+                iaid_offset = offsetof(DHCP6IA, ia_ta);
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        if (*buflen < offsetof(DHCP6Option, data) + len)
+                return -ENOBUFS;
+
+        ia_hdr = *buf;
+        ia_buflen = *buflen;
+
+        *buf += offsetof(DHCP6Option, data);
+        *buflen -= offsetof(DHCP6Option, data);
+
+        memcpy(*buf, (char*) ia + iaid_offset, len);
+
+        *buf += len;
+        *buflen -= len;
+
+        LIST_FOREACH(addresses, addr, ia->addresses) {
+                r = option_append_hdr(buf, buflen, SD_DHCP6_OPTION_IAADDR,
+                                      sizeof(addr->iaaddr));
+                if (r < 0)
+                        return r;
+
+                memcpy(*buf, &addr->iaaddr, sizeof(addr->iaaddr));
+
+                *buf += sizeof(addr->iaaddr);
+                *buflen -= sizeof(addr->iaaddr);
+
+                ia_addrlen += offsetof(DHCP6Option, data) + sizeof(addr->iaaddr);
+        }
+
+        r = option_append_hdr(&ia_hdr, &ia_buflen, ia->type, len + ia_addrlen);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int dhcp6_option_append_fqdn(uint8_t **buf, size_t *buflen, const char *fqdn) {
+        uint8_t buffer[1 + DNS_WIRE_FORMAT_HOSTNAME_MAX];
+        int r;
+
+        assert_return(buf && *buf && buflen && fqdn, -EINVAL);
+
+        buffer[0] = DHCP6_FQDN_FLAG_S; /* Request server to perform AAAA RR DNS updates */
+
+        /* Store domain name after flags field */
+        r = dns_name_to_wire_format(fqdn, buffer + 1, sizeof(buffer) - 1,  false);
+        if (r <= 0)
+                return r;
+
+        /*
+         * According to RFC 4704, chapter 4.2 only add terminating zero-length
+         * label in case a FQDN is provided. Since dns_name_to_wire_format
+         * always adds terminating zero-length label remove if only a hostname
+         * is provided.
+         */
+        if (dns_name_is_single_label(fqdn))
+                r--;
+
+        r = dhcp6_option_append(buf, buflen, SD_DHCP6_OPTION_FQDN, 1 + r, buffer);
+
+        return r;
+}
+
+int dhcp6_option_append_user_class(uint8_t **buf, size_t *buflen, char * const *user_class) {
+        _cleanup_free_ uint8_t *p = NULL;
+        size_t total = 0, offset = 0;
+        char * const *s;
+
+        assert(buf);
+        assert(*buf);
+        assert(buflen);
+        assert(!strv_isempty(user_class));
+
+        STRV_FOREACH(s, user_class) {
+                size_t len = strlen(*s);
+                uint8_t *q;
+
+                if (len > 0xffff || len == 0)
+                        return -EINVAL;
+                q = realloc(p, total + len + 2);
+                if (!q)
+                        return -ENOMEM;
+
+                p = q;
+
+                unaligned_write_be16(&p[offset], len);
+                memcpy(&p[offset + 2], *s, len);
+
+                offset += 2 + len;
+                total += 2 + len;
+        }
+
+        return dhcp6_option_append(buf, buflen, SD_DHCP6_OPTION_USER_CLASS, total, p);
+}
+
+int dhcp6_option_append_vendor_class(uint8_t **buf, size_t *buflen, char * const *vendor_class) {
+        _cleanup_free_ uint8_t *p = NULL;
+        uint32_t enterprise_identifier;
+        size_t total, offset;
+        char * const *s;
+
+        assert(buf);
+        assert(*buf);
+        assert(buflen);
+        assert(!strv_isempty(vendor_class));
+
+        enterprise_identifier = htobe32(SYSTEMD_PEN);
+
+        p = memdup(&enterprise_identifier, sizeof(enterprise_identifier));
+        if (!p)
+                return -ENOMEM;
+
+        total = sizeof(enterprise_identifier);
+        offset = total;
+
+        STRV_FOREACH(s, vendor_class) {
+                size_t len = strlen(*s);
+                uint8_t *q;
+
+                if (len > UINT16_MAX || len == 0)
+                        return -EINVAL;
+
+                q = realloc(p, total + len + 2);
+                if (!q)
+                        return -ENOMEM;
+
+                p = q;
+
+                unaligned_write_be16(&p[offset], len);
+                memcpy(&p[offset + 2], *s, len);
+
+                offset += 2 + len;
+                total += 2 + len;
+        }
+
+        return dhcp6_option_append(buf, buflen, SD_DHCP6_OPTION_VENDOR_CLASS, total, p);
+}
+
+int dhcp6_option_append_pd(uint8_t *buf, size_t len, const DHCP6IA *pd, DHCP6Address *hint_pd_prefix) {
+        DHCP6Option *option = (DHCP6Option *)buf;
+        size_t i = sizeof(*option) + sizeof(pd->ia_pd);
+        DHCP6PDPrefixOption *prefix_opt;
+        DHCP6Address *prefix;
+
+        assert_return(buf, -EINVAL);
+        assert_return(pd, -EINVAL);
+        assert_return(pd->type == SD_DHCP6_OPTION_IA_PD, -EINVAL);
+
+        if (len < i)
+                return -ENOBUFS;
+
+        option->code = htobe16(SD_DHCP6_OPTION_IA_PD);
+
+        memcpy(&option->data, &pd->ia_pd, sizeof(pd->ia_pd));
+        LIST_FOREACH(addresses, prefix, pd->addresses) {
+                if (len < i + sizeof(*prefix_opt))
+                        return -ENOBUFS;
+
+                prefix_opt = (DHCP6PDPrefixOption *)&buf[i];
+                prefix_opt->option.code = htobe16(SD_DHCP6_OPTION_IA_PD_PREFIX);
+                prefix_opt->option.len = htobe16(sizeof(prefix_opt->iapdprefix));
+
+                memcpy(&prefix_opt->iapdprefix, &prefix->iapdprefix, sizeof(struct iapdprefix));
+                i += sizeof(*prefix_opt);
+        }
+
+        if (hint_pd_prefix && hint_pd_prefix->iapdprefix.prefixlen > 0) {
+                if (len < i + sizeof(*prefix_opt))
+                        return -ENOBUFS;
+
+                prefix_opt = (DHCP6PDPrefixOption *)&buf[i];
+                prefix_opt->option.code = htobe16(SD_DHCP6_OPTION_IA_PD_PREFIX);
+                prefix_opt->option.len = htobe16(sizeof(prefix_opt->iapdprefix));
+
+                memcpy(&prefix_opt->iapdprefix, &hint_pd_prefix->iapdprefix, sizeof(struct iapdprefix));
+                i += sizeof(*prefix_opt);
+        }
+
+        option->len = htobe16(i - sizeof(*option));
+
+        return i;
+}
+
+static int option_parse_hdr(uint8_t **buf, size_t *buflen, uint16_t *optcode, size_t *optlen) {
+        DHCP6Option *option = (DHCP6Option*) *buf;
+        uint16_t len;
+
+        assert_return(buf, -EINVAL);
+        assert_return(optcode, -EINVAL);
+        assert_return(optlen, -EINVAL);
+
+        if (*buflen < offsetof(DHCP6Option, data))
+                return -ENOMSG;
+
+        len = be16toh(option->len);
+
+        if (len > *buflen)
+                return -ENOMSG;
+
+        *optcode = be16toh(option->code);
+        *optlen = len;
+
+        *buf += 4;
+        *buflen -= 4;
+
+        return 0;
+}
+
+int dhcp6_option_parse(uint8_t **buf, size_t *buflen, uint16_t *optcode,
+                       size_t *optlen, uint8_t **optvalue) {
+        int r;
+
+        assert_return(buf && buflen && optcode && optlen && optvalue, -EINVAL);
+
+        r = option_parse_hdr(buf, buflen, optcode, optlen);
+        if (r < 0)
+                return r;
+
+        if (*optlen > *buflen)
+                return -ENOBUFS;
+
+        *optvalue = *buf;
+        *buflen -= *optlen;
+        *buf += *optlen;
+
+        return 0;
+}
+
+int dhcp6_option_parse_status(DHCP6Option *option, size_t len) {
+        DHCP6StatusOption *statusopt = (DHCP6StatusOption *)option;
+
+        if (len < sizeof(DHCP6StatusOption) ||
+            be16toh(option->len) + offsetof(DHCP6Option, data) < sizeof(DHCP6StatusOption))
+                return -ENOBUFS;
+
+        return be16toh(statusopt->status);
+}
+
+static int dhcp6_option_parse_address(DHCP6Option *option, DHCP6IA *ia,
+                                      uint32_t *lifetime_valid) {
+        DHCP6AddressOption *addr_option = (DHCP6AddressOption *)option;
+        DHCP6Address *addr;
+        uint32_t lt_valid, lt_pref;
+        int r;
+
+        if (be16toh(option->len) + offsetof(DHCP6Option, data) < sizeof(*addr_option))
+                return -ENOBUFS;
+
+        lt_valid = be32toh(addr_option->iaaddr.lifetime_valid);
+        lt_pref = be32toh(addr_option->iaaddr.lifetime_preferred);
+
+        if (lt_valid == 0 || lt_pref > lt_valid) {
+                log_dhcp6_client(client, "Valid lifetime of an IA address is zero or preferred lifetime %d > valid lifetime %d",
+                                 lt_pref, lt_valid);
+
+                return 0;
+        }
+
+        if (be16toh(option->len) + offsetof(DHCP6Option, data) > sizeof(*addr_option)) {
+                r = dhcp6_option_parse_status((DHCP6Option *)addr_option->options, be16toh(option->len) + offsetof(DHCP6Option, data) - sizeof(*addr_option));
+                if (r != 0)
+                        return r < 0 ? r: 0;
+        }
+
+        addr = new0(DHCP6Address, 1);
+        if (!addr)
+                return -ENOMEM;
+
+        LIST_INIT(addresses, addr);
+        memcpy(&addr->iaaddr, option->data, sizeof(addr->iaaddr));
+
+        LIST_PREPEND(addresses, ia->addresses, addr);
+
+        *lifetime_valid = be32toh(addr->iaaddr.lifetime_valid);
+
+        return 0;
+}
+
+static int dhcp6_option_parse_pdprefix(DHCP6Option *option, DHCP6IA *ia,
+                                       uint32_t *lifetime_valid) {
+        DHCP6PDPrefixOption *pdprefix_option = (DHCP6PDPrefixOption *)option;
+        DHCP6Address *prefix;
+        uint32_t lt_valid, lt_pref;
+        int r;
+
+        if (be16toh(option->len) + offsetof(DHCP6Option, data) < sizeof(*pdprefix_option))
+                return -ENOBUFS;
+
+        lt_valid = be32toh(pdprefix_option->iapdprefix.lifetime_valid);
+        lt_pref = be32toh(pdprefix_option->iapdprefix.lifetime_preferred);
+
+        if (lt_valid == 0 || lt_pref > lt_valid) {
+                log_dhcp6_client(client, "Valid lifetieme of a PD prefix is zero or preferred lifetime %d > valid lifetime %d",
+                                 lt_pref, lt_valid);
+
+                return 0;
+        }
+
+        if (be16toh(option->len) + offsetof(DHCP6Option, data) > sizeof(*pdprefix_option)) {
+                r = dhcp6_option_parse_status((DHCP6Option *)pdprefix_option->options, be16toh(option->len) + offsetof(DHCP6Option, data) - sizeof(*pdprefix_option));
+                if (r != 0)
+                        return r < 0 ? r: 0;
+        }
+
+        prefix = new0(DHCP6Address, 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        LIST_INIT(addresses, prefix);
+        memcpy(&prefix->iapdprefix, option->data, sizeof(prefix->iapdprefix));
+
+        LIST_PREPEND(addresses, ia->addresses, prefix);
+
+        *lifetime_valid = be32toh(prefix->iapdprefix.lifetime_valid);
+
+        return 0;
+}
+
+int dhcp6_option_parse_ia(DHCP6Option *iaoption, DHCP6IA *ia, uint16_t *ret_status_code) {
+        uint32_t lt_t1, lt_t2, lt_valid = 0, lt_min = UINT32_MAX;
+        uint16_t iatype, optlen;
+        size_t iaaddr_offset;
+        int r = 0, status;
+        size_t i, len;
+        uint16_t opt;
+
+        assert_return(ia, -EINVAL);
+        assert_return(!ia->addresses, -EINVAL);
+
+        iatype = be16toh(iaoption->code);
+        len = be16toh(iaoption->len);
+
+        switch (iatype) {
+        case SD_DHCP6_OPTION_IA_NA:
+
+                if (len < DHCP6_OPTION_IA_NA_LEN)
+                        return -ENOBUFS;
+
+                iaaddr_offset = DHCP6_OPTION_IA_NA_LEN;
+                memcpy(&ia->ia_na, iaoption->data, sizeof(ia->ia_na));
+
+                lt_t1 = be32toh(ia->ia_na.lifetime_t1);
+                lt_t2 = be32toh(ia->ia_na.lifetime_t2);
+
+                if (lt_t1 && lt_t2 && lt_t1 > lt_t2) {
+                        log_dhcp6_client(client, "IA NA T1 %ds > T2 %ds",
+                                         lt_t1, lt_t2);
+                        return -EINVAL;
+                }
+
+                break;
+
+        case SD_DHCP6_OPTION_IA_PD:
+
+                if (len < sizeof(ia->ia_pd))
+                        return -ENOBUFS;
+
+                iaaddr_offset = sizeof(ia->ia_pd);
+                memcpy(&ia->ia_pd, iaoption->data, sizeof(ia->ia_pd));
+
+                lt_t1 = be32toh(ia->ia_pd.lifetime_t1);
+                lt_t2 = be32toh(ia->ia_pd.lifetime_t2);
+
+                if (lt_t1 && lt_t2 && lt_t1 > lt_t2) {
+                        log_dhcp6_client(client, "IA PD T1 %ds > T2 %ds",
+                                         lt_t1, lt_t2);
+                        return -EINVAL;
+                }
+
+                break;
+
+        case SD_DHCP6_OPTION_IA_TA:
+                if (len < DHCP6_OPTION_IA_TA_LEN)
+                        return -ENOBUFS;
+
+                iaaddr_offset = DHCP6_OPTION_IA_TA_LEN;
+                memcpy(&ia->ia_ta.id, iaoption->data, sizeof(ia->ia_ta));
+
+                break;
+
+        default:
+                return -ENOMSG;
+        }
+
+        ia->type = iatype;
+        i = iaaddr_offset;
+
+        while (i < len) {
+                DHCP6Option *option = (DHCP6Option *)&iaoption->data[i];
+
+                if (len < i + sizeof(*option) || len < i + sizeof(*option) + be16toh(option->len))
+                        return -ENOBUFS;
+
+                opt = be16toh(option->code);
+                optlen = be16toh(option->len);
+
+                switch (opt) {
+                case SD_DHCP6_OPTION_IAADDR:
+
+                        if (!IN_SET(ia->type, SD_DHCP6_OPTION_IA_NA, SD_DHCP6_OPTION_IA_TA)) {
+                                log_dhcp6_client(client, "IA Address option not in IA NA or TA option");
+                                return -EINVAL;
+                        }
+
+                        r = dhcp6_option_parse_address(option, ia, &lt_valid);
+                        if (r < 0)
+                                return r;
+
+                        if (lt_valid < lt_min)
+                                lt_min = lt_valid;
+
+                        break;
+
+                case SD_DHCP6_OPTION_IA_PD_PREFIX:
+
+                        if (!IN_SET(ia->type, SD_DHCP6_OPTION_IA_PD)) {
+                                log_dhcp6_client(client, "IA PD Prefix option not in IA PD option");
+                                return -EINVAL;
+                        }
+
+                        r = dhcp6_option_parse_pdprefix(option, ia, &lt_valid);
+                        if (r < 0)
+                                return r;
+
+                        if (lt_valid < lt_min)
+                                lt_min = lt_valid;
+
+                        break;
+
+                case SD_DHCP6_OPTION_STATUS_CODE:
+
+                        status = dhcp6_option_parse_status(option, optlen + offsetof(DHCP6Option, data));
+                        if (status < 0)
+                                return status;
+
+                        if (status > 0) {
+                                if (ret_status_code)
+                                        *ret_status_code = status;
+
+                                log_dhcp6_client(client, "IA status %s",
+                                                 dhcp6_message_status_to_string(status));
+
+                                return 0;
+                        }
+
+                        break;
+
+                default:
+                        log_dhcp6_client(client, "Unknown IA option %d", opt);
+                        break;
+                }
+
+                i += sizeof(*option) + optlen;
+        }
+
+        switch(iatype) {
+        case SD_DHCP6_OPTION_IA_NA:
+                if (!ia->ia_na.lifetime_t1 && !ia->ia_na.lifetime_t2) {
+                        lt_t1 = lt_min / 2;
+                        lt_t2 = lt_min / 10 * 8;
+                        ia->ia_na.lifetime_t1 = htobe32(lt_t1);
+                        ia->ia_na.lifetime_t2 = htobe32(lt_t2);
+
+                        log_dhcp6_client(client, "Computed IA NA T1 %ds and T2 %ds as both were zero",
+                                         lt_t1, lt_t2);
+                }
+
+                break;
+
+        case SD_DHCP6_OPTION_IA_PD:
+                if (!ia->ia_pd.lifetime_t1 && !ia->ia_pd.lifetime_t2) {
+                        lt_t1 = lt_min / 2;
+                        lt_t2 = lt_min / 10 * 8;
+                        ia->ia_pd.lifetime_t1 = htobe32(lt_t1);
+                        ia->ia_pd.lifetime_t2 = htobe32(lt_t2);
+
+                        log_dhcp6_client(client, "Computed IA PD T1 %ds and T2 %ds as both were zero",
+                                         lt_t1, lt_t2);
+                }
+
+                break;
+
+        default:
+                break;
+        }
+
+        if (ret_status_code)
+                *ret_status_code = 0;
+
+        return 1;
+}
+
+int dhcp6_option_parse_ip6addrs(uint8_t *optval, uint16_t optlen,
+                                struct in6_addr **addrs, size_t count,
+                                size_t *allocated) {
+
+        if (optlen == 0 || optlen % sizeof(struct in6_addr) != 0)
+                return -EINVAL;
+
+        if (!GREEDY_REALLOC(*addrs, *allocated,
+                            count * sizeof(struct in6_addr) + optlen))
+                return -ENOMEM;
+
+        memcpy(*addrs + count, optval, optlen);
+
+        count += optlen / sizeof(struct in6_addr);
+
+        return count;
+}
+
+static int parse_domain(const uint8_t **data, uint16_t *len, char **out_domain) {
+        _cleanup_free_ char *ret = NULL;
+        size_t n = 0, allocated = 0;
+        const uint8_t *optval = *data;
+        uint16_t optlen = *len;
+        bool first = true;
+        int r;
+
+        if (optlen <= 1)
+                return -ENODATA;
+
+        for (;;) {
+                const char *label;
+                uint8_t c;
+
+                if (optlen == 0)
+                        break;
+
+                c = *optval;
+                optval++;
+                optlen--;
+
+                if (c == 0)
+                        /* End label */
+                        break;
+                if (c > 63)
+                        return -EBADMSG;
+                if (c > optlen)
+                        return -EMSGSIZE;
+
+                /* Literal label */
+                label = (const char *)optval;
+                optval += c;
+                optlen -= c;
+
+                if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
+                        return -ENOMEM;
+
+                if (first)
+                        first = false;
+                else
+                        ret[n++] = '.';
+
+                r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
+                if (r < 0)
+                        return r;
+
+                n += r;
+        }
+
+        if (n) {
+                if (!GREEDY_REALLOC(ret, allocated, n + 1))
+                        return -ENOMEM;
+                ret[n] = 0;
+        }
+
+        *out_domain = TAKE_PTR(ret);
+        *data = optval;
+        *len = optlen;
+
+        return n;
+}
+
+int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char **str) {
+        _cleanup_free_ char *domain = NULL;
+        int r;
+
+        r = parse_domain(&optval, &optlen, &domain);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ENODATA;
+        if (optlen != 0)
+                return -EINVAL;
+
+        *str = TAKE_PTR(domain);
+        return 0;
+}
+
+int dhcp6_option_parse_domainname_list(const uint8_t *optval, uint16_t optlen, char ***str_arr) {
+        size_t idx = 0;
+        _cleanup_strv_free_ char **names = NULL;
+        int r;
+
+        if (optlen <= 1)
+                return -ENODATA;
+        if (optval[optlen - 1] != '\0')
+                return -EINVAL;
+
+        while (optlen > 0) {
+                _cleanup_free_ char *ret = NULL;
+
+                r = parse_domain(&optval, &optlen, &ret);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                r = strv_extend(&names, ret);
+                if (r < 0)
+                        return r;
+
+                idx++;
+        }
+
+        *str_arr = TAKE_PTR(names);
+
+        return idx;
+}
+
+static sd_dhcp6_option* dhcp6_option_free(sd_dhcp6_option *i) {
+        if (!i)
+                return NULL;
+
+        free(i->data);
+        return mfree(i);
+}
+
+int sd_dhcp6_option_new(uint16_t option, const void *data, size_t length, uint32_t enterprise_identifier, sd_dhcp6_option **ret) {
+        assert_return(ret, -EINVAL);
+        assert_return(length == 0 || data, -EINVAL);
+
+        _cleanup_free_ void *q = memdup(data, length);
+        if (!q)
+                return -ENOMEM;
+
+        sd_dhcp6_option *p = new(sd_dhcp6_option, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (sd_dhcp6_option) {
+                .n_ref = 1,
+                .option = option,
+                .enterprise_identifier = enterprise_identifier,
+                .length = length,
+                .data = TAKE_PTR(q),
+        };
+
+        *ret = p;
+        return 0;
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp6_option, sd_dhcp6_option, dhcp6_option_free);
+DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
+                dhcp6_option_hash_ops,
+                void,
+                trivial_hash_func,
+                trivial_compare_func,
+                sd_dhcp6_option,
+                sd_dhcp6_option_unref);
diff --git a/src/libsystemd-network/dhcp6-protocol.h b/src/libsystemd-network/dhcp6-protocol.h
new file mode 100644
index 0000000..c700363
--- /dev/null
+++ b/src/libsystemd-network/dhcp6-protocol.h
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/ip6.h>
+#include <netinet/udp.h>
+
+#include "macro.h"
+#include "sparse-endian.h"
+
+struct DHCP6Message {
+        union {
+                struct {
+                        uint8_t type;
+                        uint8_t _pad[3];
+                } _packed_;
+                be32_t transaction_id;
+        };
+        uint8_t options[];
+} _packed_;
+
+typedef struct DHCP6Message DHCP6Message;
+
+#define DHCP6_MIN_OPTIONS_SIZE \
+        1280 - sizeof(struct ip6_hdr) - sizeof(struct udphdr)
+
+#define IN6ADDR_ALL_DHCP6_RELAY_AGENTS_AND_SERVERS_INIT \
+        { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+              0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02 } } }
+
+enum {
+        DHCP6_PORT_SERVER                       = 547,
+        DHCP6_PORT_CLIENT                       = 546,
+};
+
+#define DHCP6_INF_TIMEOUT                       1 * USEC_PER_SEC
+#define DHCP6_INF_MAX_RT                        120 * USEC_PER_SEC
+#define DHCP6_SOL_MAX_DELAY                     1 * USEC_PER_SEC
+#define DHCP6_SOL_TIMEOUT                       1 * USEC_PER_SEC
+#define DHCP6_SOL_MAX_RT                        120 * USEC_PER_SEC
+#define DHCP6_REQ_TIMEOUT                       1 * USEC_PER_SEC
+#define DHCP6_REQ_MAX_RT                        120 * USEC_PER_SEC
+#define DHCP6_REQ_MAX_RC                        10
+#define DHCP6_REN_TIMEOUT                       10 * USEC_PER_SEC
+#define DHCP6_REN_MAX_RT                        600 * USEC_PER_SEC
+#define DHCP6_REB_TIMEOUT                       10 * USEC_PER_SEC
+#define DHCP6_REB_MAX_RT                        600 * USEC_PER_SEC
+
+enum DHCP6State {
+        DHCP6_STATE_STOPPED                     = 0,
+        DHCP6_STATE_INFORMATION_REQUEST         = 1,
+        DHCP6_STATE_SOLICITATION                = 2,
+        DHCP6_STATE_REQUEST                     = 3,
+        DHCP6_STATE_BOUND                       = 4,
+        DHCP6_STATE_RENEW                       = 5,
+        DHCP6_STATE_REBIND                      = 6,
+};
+
+enum {
+        DHCP6_SOLICIT                           = 1,
+        DHCP6_ADVERTISE                         = 2,
+        DHCP6_REQUEST                           = 3,
+        DHCP6_CONFIRM                           = 4,
+        DHCP6_RENEW                             = 5,
+        DHCP6_REBIND                            = 6,
+        DHCP6_REPLY                             = 7,
+        DHCP6_RELEASE                           = 8,
+        DHCP6_DECLINE                           = 9,
+        DHCP6_RECONFIGURE                       = 10,
+        DHCP6_INFORMATION_REQUEST               = 11,
+        DHCP6_RELAY_FORW                        = 12,
+        DHCP6_RELAY_REPL                        = 13,
+        _DHCP6_MESSAGE_MAX                      = 14,
+};
+
+enum {
+        DHCP6_NTP_SUBOPTION_SRV_ADDR            = 1,
+        DHCP6_NTP_SUBOPTION_MC_ADDR             = 2,
+        DHCP6_NTP_SUBOPTION_SRV_FQDN            = 3,
+};
+
+/*
+ * RFC 8415, RFC 5007 and RFC 7653 status codes:
+ * https://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xhtml#dhcpv6-parameters-5
+ */
+enum {
+        DHCP6_STATUS_SUCCESS                      = 0,
+        DHCP6_STATUS_UNSPEC_FAIL                  = 1,
+        DHCP6_STATUS_NO_ADDRS_AVAIL               = 2,
+        DHCP6_STATUS_NO_BINDING                   = 3,
+        DHCP6_STATUS_NOT_ON_LINK                  = 4,
+        DHCP6_STATUS_USE_MULTICAST                = 5,
+        DHCP6_STATUS_NO_PREFIX_AVAIL              = 6,
+        DHCP6_STATUS_UNKNOWN_QUERY_TYPE           = 7,
+        DHCP6_STATUS_MALFORMED_QUERY              = 8,
+        DHCP6_STATUS_NOT_CONFIGURED               = 9,
+        DHCP6_STATUS_NOT_ALLOWED                  = 10,
+        DHCP6_STATUS_QUERY_TERMINATED             = 11,
+        DHCP6_STATUS_DATA_MISSING                 = 12,
+        DHCP6_STATUS_CATCHUP_COMPLETE             = 13,
+        DHCP6_STATUS_NOT_SUPPORTED                = 14,
+        DHCP6_STATUS_TLS_CONNECTION_REFUSED       = 15,
+        DHCP6_STATUS_ADDRESS_IN_USE               = 16,
+        DHCP6_STATUS_CONFIGURATION_CONFLICT       = 17,
+        DHCP6_STATUS_MISSING_BINDING_INFORMATION  = 18,
+        DHCP6_STATUS_OUTDATED_BINDING_INFORMATION = 19,
+        DHCP6_STATUS_SERVER_SHUTTING_DOWN         = 20,
+        DHCP6_STATUS_DNS_UPDATE_NOT_SUPPORTED     = 21,
+        DHCP6_STATUS_EXCESSIVE_TIME_SKEW          = 22,
+        _DHCP6_STATUS_MAX                         = 23,
+};
+
+enum {
+        DHCP6_FQDN_FLAG_S = (1 << 0),
+        DHCP6_FQDN_FLAG_O = (1 << 1),
+        DHCP6_FQDN_FLAG_N = (1 << 2),
+};
diff --git a/src/libsystemd-network/icmp6-util.c b/src/libsystemd-network/icmp6-util.c
new file mode 100644
index 0000000..4af0125
--- /dev/null
+++ b/src/libsystemd-network/icmp6-util.c
@@ -0,0 +1,210 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <netinet/icmp6.h>
+#include <netinet/in.h>
+#include <netinet/ip6.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <linux/if_packet.h>
+
+#include "fd-util.h"
+#include "icmp6-util.h"
+#include "in-addr-util.h"
+#include "io-util.h"
+#include "socket-util.h"
+
+#define IN6ADDR_ALL_ROUTERS_MULTICAST_INIT \
+        { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02 } } }
+
+#define IN6ADDR_ALL_NODES_MULTICAST_INIT \
+        { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } } }
+
+static int icmp6_bind_router_message(const struct icmp6_filter *filter,
+                                     const struct ipv6_mreq *mreq) {
+        int ifindex = mreq->ipv6mr_interface;
+        _cleanup_close_ int s = -1;
+        int r;
+
+        s = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_ICMPV6);
+        if (s < 0)
+                return -errno;
+
+        r = setsockopt(s, IPPROTO_ICMPV6, ICMP6_FILTER, filter, sizeof(*filter));
+        if (r < 0)
+                return -errno;
+
+        r = setsockopt(s, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, mreq, sizeof(*mreq));
+        if (r < 0)
+                return -errno;
+
+        /* RFC 3315, section 6.7, bullet point 2 may indicate that an
+           IPV6_PKTINFO socket option also applies for ICMPv6 multicast.
+           Empirical experiments indicates otherwise and therefore an
+           IPV6_MULTICAST_IF socket option is used here instead */
+        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_IF, ifindex);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, false);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, 255);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, IPPROTO_IPV6, IPV6_UNICAST_HOPS, 255);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, SOL_IPV6, IPV6_RECVHOPLIMIT, true);
+        if (r < 0)
+                return r;
+
+        r = setsockopt_int(s, SOL_SOCKET, SO_TIMESTAMP, true);
+        if (r < 0)
+                return r;
+
+        r = socket_bind_to_ifindex(s, ifindex);
+        if (r < 0)
+                return r;
+
+        return TAKE_FD(s);
+}
+
+int icmp6_bind_router_solicitation(int ifindex) {
+        struct icmp6_filter filter = {};
+        struct ipv6_mreq mreq = {
+                .ipv6mr_multiaddr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
+                .ipv6mr_interface = ifindex,
+        };
+
+        ICMP6_FILTER_SETBLOCKALL(&filter);
+        ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filter);
+
+        return icmp6_bind_router_message(&filter, &mreq);
+}
+
+int icmp6_bind_router_advertisement(int ifindex) {
+        struct icmp6_filter filter = {};
+        struct ipv6_mreq mreq = {
+                .ipv6mr_multiaddr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
+                .ipv6mr_interface = ifindex,
+        };
+
+        ICMP6_FILTER_SETBLOCKALL(&filter);
+        ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filter);
+
+        return icmp6_bind_router_message(&filter, &mreq);
+}
+
+int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) {
+        struct sockaddr_in6 dst = {
+                .sin6_family = AF_INET6,
+                .sin6_addr = IN6ADDR_ALL_ROUTERS_MULTICAST_INIT,
+        };
+        struct {
+                struct nd_router_solicit rs;
+                struct nd_opt_hdr rs_opt;
+                struct ether_addr rs_opt_mac;
+        } _packed_ rs = {
+                .rs.nd_rs_type = ND_ROUTER_SOLICIT,
+                .rs_opt.nd_opt_type = ND_OPT_SOURCE_LINKADDR,
+                .rs_opt.nd_opt_len = 1,
+        };
+        struct iovec iov = {
+                .iov_base = &rs,
+                .iov_len = sizeof(rs),
+        };
+        struct msghdr msg = {
+                .msg_name = &dst,
+                .msg_namelen = sizeof(dst),
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+        };
+        int r;
+
+        assert(s >= 0);
+        assert(ether_addr);
+
+        rs.rs_opt_mac = *ether_addr;
+
+        r = sendmsg(s, &msg, 0);
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+int icmp6_receive(int fd, void *buffer, size_t size, struct in6_addr *dst,
+                  triple_timestamp *timestamp) {
+
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int)) + /* ttl */
+                         CMSG_SPACE(sizeof(struct timeval))) control;
+        struct iovec iov = {};
+        union sockaddr_union sa = {};
+        struct msghdr msg = {
+                .msg_name = &sa.sa,
+                .msg_namelen = sizeof(sa),
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+        };
+        struct cmsghdr *cmsg;
+        ssize_t len;
+
+        iov = IOVEC_MAKE(buffer, size);
+
+        len = recvmsg_safe(fd, &msg, MSG_DONTWAIT);
+        if (len < 0)
+                return (int) len;
+
+        if ((size_t) len != size)
+                return -EINVAL;
+
+        if (msg.msg_namelen == sizeof(struct sockaddr_in6) &&
+            sa.in6.sin6_family == AF_INET6)  {
+
+                *dst = sa.in6.sin6_addr;
+                if (in_addr_is_link_local(AF_INET6, (union in_addr_union*) dst) <= 0)
+                        return -EADDRNOTAVAIL;
+
+        } else if (msg.msg_namelen > 0)
+                return -EPFNOSUPPORT;
+
+        /* namelen == 0 only happens when running the test-suite over a socketpair */
+
+        assert(!(msg.msg_flags & MSG_CTRUNC));
+        assert(!(msg.msg_flags & MSG_TRUNC));
+
+        CMSG_FOREACH(cmsg, &msg) {
+                if (cmsg->cmsg_level == SOL_IPV6 &&
+                    cmsg->cmsg_type == IPV6_HOPLIMIT &&
+                    cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
+                        int hops = *(int*) CMSG_DATA(cmsg);
+
+                        if (hops != 255)
+                                return -EMULTIHOP;
+                }
+
+                if (cmsg->cmsg_level == SOL_SOCKET &&
+                    cmsg->cmsg_type == SO_TIMESTAMP &&
+                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval)))
+                        triple_timestamp_from_realtime(timestamp, timeval_load((struct timeval*) CMSG_DATA(cmsg)));
+        }
+
+        if (!triple_timestamp_is_set(timestamp))
+                triple_timestamp_get(timestamp);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/icmp6-util.h b/src/libsystemd-network/icmp6-util.h
new file mode 100644
index 0000000..50d21b5
--- /dev/null
+++ b/src/libsystemd-network/icmp6-util.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014-2015 Intel Corporation. All rights reserved.
+***/
+
+#include <net/ethernet.h>
+
+#include "time-util.h"
+
+#define IN6ADDR_ALL_ROUTERS_MULTICAST_INIT \
+        { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02 } } }
+
+#define IN6ADDR_ALL_NODES_MULTICAST_INIT \
+        { { { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+              0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 } } }
+
+int icmp6_bind_router_solicitation(int ifindex);
+int icmp6_bind_router_advertisement(int ifindex);
+int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr);
+int icmp6_receive(int fd, void *buffer, size_t size, struct in6_addr *dst,
+                  triple_timestamp *timestamp);
diff --git a/src/libsystemd-network/lldp-internal.h b/src/libsystemd-network/lldp-internal.h
new file mode 100644
index 0000000..f23695f
--- /dev/null
+++ b/src/libsystemd-network/lldp-internal.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-event.h"
+#include "sd-lldp.h"
+
+#include "hashmap.h"
+#include "log.h"
+#include "prioq.h"
+
+struct sd_lldp {
+        unsigned n_ref;
+
+        int ifindex;
+        int fd;
+
+        sd_event *event;
+        int64_t event_priority;
+        sd_event_source *io_event_source;
+        sd_event_source *timer_event_source;
+
+        Prioq *neighbor_by_expiry;
+        Hashmap *neighbor_by_id;
+
+        uint64_t neighbors_max;
+
+        sd_lldp_callback_t callback;
+        void *userdata;
+
+        uint16_t capability_mask;
+
+        struct ether_addr filter_address;
+};
+
+#define log_lldp_errno(error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "LLDP: " fmt, ##__VA_ARGS__)
+#define log_lldp(fmt, ...) log_lldp_errno(0, fmt, ##__VA_ARGS__)
+
+const char* lldp_event_to_string(sd_lldp_event e) _const_;
+sd_lldp_event lldp_event_from_string(const char *s) _pure_;
diff --git a/src/libsystemd-network/lldp-neighbor.c b/src/libsystemd-network/lldp-neighbor.c
new file mode 100644
index 0000000..546ae1c
--- /dev/null
+++ b/src/libsystemd-network/lldp-neighbor.c
@@ -0,0 +1,792 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "escape.h"
+#include "ether-addr-util.h"
+#include "hexdecoct.h"
+#include "in-addr-util.h"
+#include "lldp-internal.h"
+#include "lldp-neighbor.h"
+#include "memory-util.h"
+#include "missing_network.h"
+#include "unaligned.h"
+
+static void lldp_neighbor_id_hash_func(const LLDPNeighborID *id, struct siphash *state) {
+        siphash24_compress(id->chassis_id, id->chassis_id_size, state);
+        siphash24_compress(&id->chassis_id_size, sizeof(id->chassis_id_size), state);
+        siphash24_compress(id->port_id, id->port_id_size, state);
+        siphash24_compress(&id->port_id_size, sizeof(id->port_id_size), state);
+}
+
+int lldp_neighbor_id_compare_func(const LLDPNeighborID *x, const LLDPNeighborID *y) {
+        return memcmp_nn(x->chassis_id, x->chassis_id_size, y->chassis_id, y->chassis_id_size)
+            ?: memcmp_nn(x->port_id, x->port_id_size, y->port_id, y->port_id_size);
+}
+
+DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(lldp_neighbor_hash_ops, LLDPNeighborID, lldp_neighbor_id_hash_func, lldp_neighbor_id_compare_func,
+                                      sd_lldp_neighbor, lldp_neighbor_unlink);
+
+int lldp_neighbor_prioq_compare_func(const void *a, const void *b) {
+        const sd_lldp_neighbor *x = a, *y = b;
+
+        return CMP(x->until, y->until);
+}
+
+_public_ sd_lldp_neighbor *sd_lldp_neighbor_ref(sd_lldp_neighbor *n) {
+        if (!n)
+                return NULL;
+
+        assert(n->n_ref > 0 || n->lldp);
+        n->n_ref++;
+
+        return n;
+}
+
+static void lldp_neighbor_free(sd_lldp_neighbor *n) {
+        assert(n);
+
+        free(n->id.port_id);
+        free(n->id.chassis_id);
+        free(n->port_description);
+        free(n->system_name);
+        free(n->system_description);
+        free(n->mud_url);
+        free(n->chassis_id_as_string);
+        free(n->port_id_as_string);
+        free(n);
+}
+
+_public_ sd_lldp_neighbor *sd_lldp_neighbor_unref(sd_lldp_neighbor *n) {
+
+        /* Drops one reference from the neighbor. Note that the object is not freed unless it is already unlinked from
+         * the sd_lldp object. */
+
+        if (!n)
+                return NULL;
+
+        assert(n->n_ref > 0);
+        n->n_ref--;
+
+        if (n->n_ref <= 0 && !n->lldp)
+                lldp_neighbor_free(n);
+
+        return NULL;
+}
+
+sd_lldp_neighbor *lldp_neighbor_unlink(sd_lldp_neighbor *n) {
+
+        /* Removes the neighbor object from the LLDP object, and frees it if it also has no other reference. */
+
+        if (!n)
+                return NULL;
+
+        if (!n->lldp)
+                return NULL;
+
+        /* Only remove the neighbor object from the hash table if it's in there, don't complain if it isn't. This is
+         * because we are used as destructor call for hashmap_clear() and thus sometimes are called to de-register
+         * ourselves from the hashtable and sometimes are called after we already are de-registered. */
+
+        (void) hashmap_remove_value(n->lldp->neighbor_by_id, &n->id, n);
+
+        assert_se(prioq_remove(n->lldp->neighbor_by_expiry, n, &n->prioq_idx) >= 0);
+
+        n->lldp = NULL;
+
+        if (n->n_ref <= 0)
+                lldp_neighbor_free(n);
+
+        return NULL;
+}
+
+sd_lldp_neighbor *lldp_neighbor_new(size_t raw_size) {
+        sd_lldp_neighbor *n;
+
+        n = malloc0(ALIGN(sizeof(sd_lldp_neighbor)) + raw_size);
+        if (!n)
+                return NULL;
+
+        n->raw_size = raw_size;
+        n->n_ref = 1;
+
+        return n;
+}
+
+static int parse_string(char **s, const void *q, size_t n) {
+        const char *p = q;
+        char *k;
+
+        assert(s);
+        assert(p || n == 0);
+
+        if (*s) {
+                log_lldp("Found duplicate string, ignoring field.");
+                return 0;
+        }
+
+        /* Strip trailing NULs, just to be nice */
+        while (n > 0 && p[n-1] == 0)
+                n--;
+
+        if (n <= 0) /* Ignore empty strings */
+                return 0;
+
+        /* Look for inner NULs */
+        if (memchr(p, 0, n)) {
+                log_lldp("Found inner NUL in string, ignoring field.");
+                return 0;
+        }
+
+        /* Let's escape weird chars, for security reasons */
+        k = cescape_length(p, n);
+        if (!k)
+                return -ENOMEM;
+
+        free(*s);
+        *s = k;
+
+        return 1;
+}
+
+int lldp_neighbor_parse(sd_lldp_neighbor *n) {
+        struct ether_header h;
+        const uint8_t *p;
+        size_t left;
+        int r;
+
+        assert(n);
+
+        if (n->raw_size < sizeof(struct ether_header)) {
+                log_lldp("Received truncated packet, ignoring.");
+                return -EBADMSG;
+        }
+
+        memcpy(&h, LLDP_NEIGHBOR_RAW(n), sizeof(h));
+
+        if (h.ether_type != htobe16(ETHERTYPE_LLDP)) {
+                log_lldp("Received packet with wrong type, ignoring.");
+                return -EBADMSG;
+        }
+
+        if (h.ether_dhost[0] != 0x01 ||
+            h.ether_dhost[1] != 0x80 ||
+            h.ether_dhost[2] != 0xc2 ||
+            h.ether_dhost[3] != 0x00 ||
+            h.ether_dhost[4] != 0x00 ||
+            !IN_SET(h.ether_dhost[5], 0x00, 0x03, 0x0e)) {
+                log_lldp("Received packet with wrong destination address, ignoring.");
+                return -EBADMSG;
+        }
+
+        memcpy(&n->source_address, h.ether_shost, sizeof(struct ether_addr));
+        memcpy(&n->destination_address, h.ether_dhost, sizeof(struct ether_addr));
+
+        p = (const uint8_t*) LLDP_NEIGHBOR_RAW(n) + sizeof(struct ether_header);
+        left = n->raw_size - sizeof(struct ether_header);
+
+        for (;;) {
+                uint8_t type;
+                uint16_t length;
+
+                if (left < 2) {
+                        log_lldp("TLV lacks header, ignoring.");
+                        return -EBADMSG;
+                }
+
+                type = p[0] >> 1;
+                length = p[1] + (((uint16_t) (p[0] & 1)) << 8);
+                p += 2, left -= 2;
+
+                if (left < length) {
+                        log_lldp("TLV truncated, ignoring datagram.");
+                        return -EBADMSG;
+                }
+
+                switch (type) {
+
+                case SD_LLDP_TYPE_END:
+                        if (length != 0) {
+                                log_lldp("End marker TLV not zero-sized, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        /* Note that after processing the SD_LLDP_TYPE_END left could still be > 0
+                         * as the message may contain padding (see IEEE 802.1AB-2016, sec. 8.5.12) */
+
+                        goto end_marker;
+
+                case SD_LLDP_TYPE_CHASSIS_ID:
+                        if (length < 2 || length > 256) { /* includes the chassis subtype, hence one extra byte */
+                                log_lldp("Chassis ID field size out of range, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+                        if (n->id.chassis_id) {
+                                log_lldp("Duplicate chassis ID field, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        n->id.chassis_id = memdup(p, length);
+                        if (!n->id.chassis_id)
+                                return -ENOMEM;
+
+                        n->id.chassis_id_size = length;
+                        break;
+
+                case SD_LLDP_TYPE_PORT_ID:
+                        if (length < 2 || length > 256) { /* includes the port subtype, hence one extra byte */
+                                log_lldp("Port ID field size out of range, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+                        if (n->id.port_id) {
+                                log_lldp("Duplicate port ID field, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        n->id.port_id = memdup(p, length);
+                        if (!n->id.port_id)
+                                return -ENOMEM;
+
+                        n->id.port_id_size = length;
+                        break;
+
+                case SD_LLDP_TYPE_TTL:
+                        if (length != 2) {
+                                log_lldp("TTL field has wrong size, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        if (n->has_ttl) {
+                                log_lldp("Duplicate TTL field, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        n->ttl = unaligned_read_be16(p);
+                        n->has_ttl = true;
+                        break;
+
+                case SD_LLDP_TYPE_PORT_DESCRIPTION:
+                        r = parse_string(&n->port_description, p, length);
+                        if (r < 0)
+                                return r;
+                        break;
+
+                case SD_LLDP_TYPE_SYSTEM_NAME:
+                        r = parse_string(&n->system_name, p, length);
+                        if (r < 0)
+                                return r;
+                        break;
+
+                case SD_LLDP_TYPE_SYSTEM_DESCRIPTION:
+                        r = parse_string(&n->system_description, p, length);
+                        if (r < 0)
+                                return r;
+                        break;
+
+                case SD_LLDP_TYPE_SYSTEM_CAPABILITIES:
+                        if (length != 4)
+                                log_lldp("System capabilities field has wrong size, ignoring.");
+                        else {
+                                n->system_capabilities = unaligned_read_be16(p);
+                                n->enabled_capabilities = unaligned_read_be16(p + 2);
+                                n->has_capabilities = true;
+                        }
+
+                        break;
+
+                case SD_LLDP_TYPE_PRIVATE: {
+                        if (length < 4)
+                                log_lldp("Found private TLV that is too short, ignoring.");
+                        else {
+                                /* RFC 8520: MUD URL */
+                                if (memcmp(p, SD_LLDP_OUI_MUD, sizeof(SD_LLDP_OUI_MUD)) == 0 &&
+                                    p[sizeof(SD_LLDP_OUI_MUD)] == SD_LLDP_OUI_SUBTYPE_MUD_USAGE_DESCRIPTION) {
+                                        r = parse_string(&n->mud_url, p + sizeof(SD_LLDP_OUI_MUD) + 1,
+                                                         length - 1 - sizeof(SD_LLDP_OUI_MUD));
+                                        if (r < 0)
+                                                return r;
+                                }
+                        }
+                }
+
+                        break;
+                }
+
+                p += length, left -= length;
+        }
+
+end_marker:
+        if (!n->id.chassis_id || !n->id.port_id || !n->has_ttl) {
+                log_lldp("One or more mandatory TLV missing in datagram. Ignoring.");
+                return -EBADMSG;
+
+        }
+
+        n->rindex = sizeof(struct ether_header);
+
+        return 0;
+}
+
+void lldp_neighbor_start_ttl(sd_lldp_neighbor *n) {
+        assert(n);
+
+        if (n->ttl > 0) {
+                usec_t base;
+
+                /* Use the packet's timestamp if there is one known */
+                base = triple_timestamp_by_clock(&n->timestamp, clock_boottime_or_monotonic());
+                if (base <= 0 || base == USEC_INFINITY)
+                        base = now(clock_boottime_or_monotonic()); /* Otherwise, take the current time */
+
+                n->until = usec_add(base, n->ttl * USEC_PER_SEC);
+        } else
+                n->until = 0;
+
+        if (n->lldp)
+                prioq_reshuffle(n->lldp->neighbor_by_expiry, n, &n->prioq_idx);
+}
+
+bool lldp_neighbor_equal(const sd_lldp_neighbor *a, const sd_lldp_neighbor *b) {
+        if (a == b)
+                return true;
+
+        if (!a || !b)
+                return false;
+
+        if (a->raw_size != b->raw_size)
+                return false;
+
+        return memcmp(LLDP_NEIGHBOR_RAW(a), LLDP_NEIGHBOR_RAW(b), a->raw_size) == 0;
+}
+
+_public_ int sd_lldp_neighbor_get_source_address(sd_lldp_neighbor *n, struct ether_addr* address) {
+        assert_return(n, -EINVAL);
+        assert_return(address, -EINVAL);
+
+        *address = n->source_address;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_destination_address(sd_lldp_neighbor *n, struct ether_addr* address) {
+        assert_return(n, -EINVAL);
+        assert_return(address, -EINVAL);
+
+        *address = n->destination_address;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_raw(sd_lldp_neighbor *n, const void **ret, size_t *size) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(size, -EINVAL);
+
+        *ret = LLDP_NEIGHBOR_RAW(n);
+        *size = n->raw_size;
+
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_chassis_id(sd_lldp_neighbor *n, uint8_t *type, const void **ret, size_t *size) {
+        assert_return(n, -EINVAL);
+        assert_return(type, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(size, -EINVAL);
+
+        assert(n->id.chassis_id_size > 0);
+
+        *type = *(uint8_t*) n->id.chassis_id;
+        *ret = (uint8_t*) n->id.chassis_id + 1;
+        *size = n->id.chassis_id_size - 1;
+
+        return 0;
+}
+
+static int format_mac_address(const void *data, size_t sz, char **ret) {
+        struct ether_addr a;
+        char *k;
+
+        assert(data || sz <= 0);
+
+        if (sz != 7)
+                return 0;
+
+        memcpy(&a, (uint8_t*) data + 1, sizeof(a));
+
+        k = new(char, ETHER_ADDR_TO_STRING_MAX);
+        if (!k)
+                return -ENOMEM;
+
+        *ret = ether_addr_to_string(&a, k);
+        return 1;
+}
+
+static int format_network_address(const void *data, size_t sz, char **ret) {
+        union in_addr_union a;
+        int family, r;
+
+        if (sz == 6 && ((uint8_t*) data)[1] == 1) {
+                memcpy(&a.in, (uint8_t*) data + 2, sizeof(a.in));
+                family = AF_INET;
+        } else if (sz == 18 && ((uint8_t*) data)[1] == 2) {
+                memcpy(&a.in6, (uint8_t*) data + 2, sizeof(a.in6));
+                family = AF_INET6;
+        } else
+                return 0;
+
+        r = in_addr_to_string(family, &a, ret);
+        if (r < 0)
+                return r;
+        return 1;
+}
+
+_public_ int sd_lldp_neighbor_get_chassis_id_as_string(sd_lldp_neighbor *n, const char **ret) {
+        char *k;
+        int r;
+
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (n->chassis_id_as_string) {
+                *ret = n->chassis_id_as_string;
+                return 0;
+        }
+
+        assert(n->id.chassis_id_size > 0);
+
+        switch (*(uint8_t*) n->id.chassis_id) {
+
+        case SD_LLDP_CHASSIS_SUBTYPE_CHASSIS_COMPONENT:
+        case SD_LLDP_CHASSIS_SUBTYPE_INTERFACE_ALIAS:
+        case SD_LLDP_CHASSIS_SUBTYPE_PORT_COMPONENT:
+        case SD_LLDP_CHASSIS_SUBTYPE_INTERFACE_NAME:
+        case SD_LLDP_CHASSIS_SUBTYPE_LOCALLY_ASSIGNED:
+                k = cescape_length((char*) n->id.chassis_id + 1, n->id.chassis_id_size - 1);
+                if (!k)
+                        return -ENOMEM;
+
+                goto done;
+
+        case SD_LLDP_CHASSIS_SUBTYPE_MAC_ADDRESS:
+                r = format_mac_address(n->id.chassis_id, n->id.chassis_id_size, &k);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        goto done;
+
+                break;
+
+        case SD_LLDP_CHASSIS_SUBTYPE_NETWORK_ADDRESS:
+                r = format_network_address(n->id.chassis_id, n->id.chassis_id_size, &k);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        goto done;
+
+                break;
+        }
+
+        /* Generic fallback */
+        k = hexmem(n->id.chassis_id, n->id.chassis_id_size);
+        if (!k)
+                return -ENOMEM;
+
+done:
+        *ret = n->chassis_id_as_string = k;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_port_id(sd_lldp_neighbor *n, uint8_t *type, const void **ret, size_t *size) {
+        assert_return(n, -EINVAL);
+        assert_return(type, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(size, -EINVAL);
+
+        assert(n->id.port_id_size > 0);
+
+        *type = *(uint8_t*) n->id.port_id;
+        *ret = (uint8_t*) n->id.port_id + 1;
+        *size = n->id.port_id_size - 1;
+
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_port_id_as_string(sd_lldp_neighbor *n, const char **ret) {
+        char *k;
+        int r;
+
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (n->port_id_as_string) {
+                *ret = n->port_id_as_string;
+                return 0;
+        }
+
+        assert(n->id.port_id_size > 0);
+
+        switch (*(uint8_t*) n->id.port_id) {
+
+        case SD_LLDP_PORT_SUBTYPE_INTERFACE_ALIAS:
+        case SD_LLDP_PORT_SUBTYPE_PORT_COMPONENT:
+        case SD_LLDP_PORT_SUBTYPE_INTERFACE_NAME:
+        case SD_LLDP_PORT_SUBTYPE_LOCALLY_ASSIGNED:
+                k = cescape_length((char*) n->id.port_id + 1, n->id.port_id_size - 1);
+                if (!k)
+                        return -ENOMEM;
+
+                goto done;
+
+        case SD_LLDP_PORT_SUBTYPE_MAC_ADDRESS:
+                r = format_mac_address(n->id.port_id, n->id.port_id_size, &k);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        goto done;
+
+                break;
+
+        case SD_LLDP_PORT_SUBTYPE_NETWORK_ADDRESS:
+                r = format_network_address(n->id.port_id, n->id.port_id_size, &k);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        goto done;
+
+                break;
+        }
+
+        /* Generic fallback */
+        k = hexmem(n->id.port_id, n->id.port_id_size);
+        if (!k)
+                return -ENOMEM;
+
+done:
+        *ret = n->port_id_as_string = k;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_ttl(sd_lldp_neighbor *n, uint16_t *ret_sec) {
+        assert_return(n, -EINVAL);
+        assert_return(ret_sec, -EINVAL);
+
+        *ret_sec = n->ttl;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_system_name(sd_lldp_neighbor *n, const char **ret) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!n->system_name)
+                return -ENODATA;
+
+        *ret = n->system_name;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_system_description(sd_lldp_neighbor *n, const char **ret) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!n->system_description)
+                return -ENODATA;
+
+        *ret = n->system_description;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_port_description(sd_lldp_neighbor *n, const char **ret) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!n->port_description)
+                return -ENODATA;
+
+        *ret = n->port_description;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_mud_url(sd_lldp_neighbor *n, const char **ret) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!n->mud_url)
+                return -ENODATA;
+
+        *ret = n->mud_url;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_system_capabilities(sd_lldp_neighbor *n, uint16_t *ret) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!n->has_capabilities)
+                return -ENODATA;
+
+        *ret = n->system_capabilities;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_enabled_capabilities(sd_lldp_neighbor *n, uint16_t *ret) {
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!n->has_capabilities)
+                return -ENODATA;
+
+        *ret = n->enabled_capabilities;
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_from_raw(sd_lldp_neighbor **ret, const void *raw, size_t raw_size) {
+        _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(raw || raw_size <= 0, -EINVAL);
+
+        n = lldp_neighbor_new(raw_size);
+        if (!n)
+                return -ENOMEM;
+
+        memcpy(LLDP_NEIGHBOR_RAW(n), raw, raw_size);
+        r = lldp_neighbor_parse(n);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(n);
+
+        return r;
+}
+
+_public_ int sd_lldp_neighbor_tlv_rewind(sd_lldp_neighbor *n) {
+        assert_return(n, -EINVAL);
+
+        assert(n->raw_size >= sizeof(struct ether_header));
+        n->rindex = sizeof(struct ether_header);
+
+        return n->rindex < n->raw_size;
+}
+
+_public_ int sd_lldp_neighbor_tlv_next(sd_lldp_neighbor *n) {
+        size_t length;
+
+        assert_return(n, -EINVAL);
+
+        if (n->rindex == n->raw_size) /* EOF */
+                return -ESPIPE;
+
+        if (n->rindex + 2 > n->raw_size) /* Truncated message */
+                return -EBADMSG;
+
+        length = LLDP_NEIGHBOR_TLV_LENGTH(n);
+        if (n->rindex + 2 + length > n->raw_size)
+                return -EBADMSG;
+
+        n->rindex += 2 + length;
+        return n->rindex < n->raw_size;
+}
+
+_public_ int sd_lldp_neighbor_tlv_get_type(sd_lldp_neighbor *n, uint8_t *type) {
+        assert_return(n, -EINVAL);
+        assert_return(type, -EINVAL);
+
+        if (n->rindex == n->raw_size) /* EOF */
+                return -ESPIPE;
+
+        if (n->rindex + 2 > n->raw_size)
+                return -EBADMSG;
+
+        *type = LLDP_NEIGHBOR_TLV_TYPE(n);
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_tlv_is_type(sd_lldp_neighbor *n, uint8_t type) {
+        uint8_t k;
+        int r;
+
+        assert_return(n, -EINVAL);
+
+        r = sd_lldp_neighbor_tlv_get_type(n, &k);
+        if (r < 0)
+                return r;
+
+        return type == k;
+}
+
+_public_ int sd_lldp_neighbor_tlv_get_oui(sd_lldp_neighbor *n, uint8_t oui[_SD_ARRAY_STATIC 3], uint8_t *subtype) {
+        const uint8_t *d;
+        size_t length;
+        int r;
+
+        assert_return(n, -EINVAL);
+        assert_return(oui, -EINVAL);
+        assert_return(subtype, -EINVAL);
+
+        r = sd_lldp_neighbor_tlv_is_type(n, SD_LLDP_TYPE_PRIVATE);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ENXIO;
+
+        length = LLDP_NEIGHBOR_TLV_LENGTH(n);
+        if (length < 4)
+                return -EBADMSG;
+
+        if (n->rindex + 2 + length > n->raw_size)
+                return -EBADMSG;
+
+        d = LLDP_NEIGHBOR_TLV_DATA(n);
+        memcpy(oui, d, 3);
+        *subtype = d[3];
+
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_tlv_is_oui(sd_lldp_neighbor *n, const uint8_t oui[_SD_ARRAY_STATIC 3], uint8_t subtype) {
+        uint8_t k[3], st;
+        int r;
+
+        r = sd_lldp_neighbor_tlv_get_oui(n, k, &st);
+        if (r == -ENXIO)
+                return 0;
+        if (r < 0)
+                return r;
+
+        return memcmp(k, oui, 3) == 0 && st == subtype;
+}
+
+_public_ int sd_lldp_neighbor_tlv_get_raw(sd_lldp_neighbor *n, const void **ret, size_t *size) {
+        size_t length;
+
+        assert_return(n, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(size, -EINVAL);
+
+        /* Note that this returns the full TLV, including the TLV header */
+
+        if (n->rindex + 2 > n->raw_size)
+                return -EBADMSG;
+
+        length = LLDP_NEIGHBOR_TLV_LENGTH(n);
+        if (n->rindex + 2 + length > n->raw_size)
+                return -EBADMSG;
+
+        *ret = (uint8_t*) LLDP_NEIGHBOR_RAW(n) + n->rindex;
+        *size = length + 2;
+
+        return 0;
+}
+
+_public_ int sd_lldp_neighbor_get_timestamp(sd_lldp_neighbor *n, clockid_t clock, uint64_t *ret) {
+        assert_return(n, -EINVAL);
+        assert_return(TRIPLE_TIMESTAMP_HAS_CLOCK(clock), -EOPNOTSUPP);
+        assert_return(clock_supported(clock), -EOPNOTSUPP);
+        assert_return(ret, -EINVAL);
+
+        if (!triple_timestamp_is_set(&n->timestamp))
+                return -ENODATA;
+
+        *ret = triple_timestamp_by_clock(&n->timestamp, clock);
+        return 0;
+}
diff --git a/src/libsystemd-network/lldp-neighbor.h b/src/libsystemd-network/lldp-neighbor.h
new file mode 100644
index 0000000..a5718c8
--- /dev/null
+++ b/src/libsystemd-network/lldp-neighbor.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <sys/types.h>
+
+#include "sd-lldp.h"
+
+#include "hash-funcs.h"
+#include "lldp-internal.h"
+#include "time-util.h"
+
+typedef struct LLDPNeighborID {
+        /* The spec calls this an "MSAP identifier" */
+        void *chassis_id;
+        size_t chassis_id_size;
+
+        void *port_id;
+        size_t port_id_size;
+} LLDPNeighborID;
+
+struct sd_lldp_neighbor {
+        /* Neighbor objects stay around as long as they are linked into an "sd_lldp" object or n_ref > 0. */
+        sd_lldp *lldp;
+        unsigned n_ref;
+
+        triple_timestamp timestamp;
+
+        usec_t until;
+        unsigned prioq_idx;
+
+        struct ether_addr source_address;
+        struct ether_addr destination_address;
+
+        LLDPNeighborID id;
+
+        /* The raw packet size. The data is appended to the object, accessible via LLDP_NEIGHBOR_RAW() */
+        size_t raw_size;
+
+        /* The current read index for the iterative TLV interface */
+        size_t rindex;
+
+        /* And a couple of fields parsed out. */
+        bool has_ttl:1;
+        bool has_capabilities:1;
+        bool has_port_vlan_id:1;
+
+        uint16_t ttl;
+
+        uint16_t system_capabilities;
+        uint16_t enabled_capabilities;
+
+        char *port_description;
+        char *system_name;
+        char *system_description;
+        char *mud_url;
+
+        uint16_t port_vlan_id;
+
+        char *chassis_id_as_string;
+        char *port_id_as_string;
+};
+
+static inline void *LLDP_NEIGHBOR_RAW(const sd_lldp_neighbor *n) {
+        return (uint8_t*) n + ALIGN(sizeof(sd_lldp_neighbor));
+}
+
+static inline uint8_t LLDP_NEIGHBOR_TLV_TYPE(const sd_lldp_neighbor *n) {
+        return ((uint8_t*) LLDP_NEIGHBOR_RAW(n))[n->rindex] >> 1;
+}
+
+static inline size_t LLDP_NEIGHBOR_TLV_LENGTH(const sd_lldp_neighbor *n) {
+        uint8_t *p;
+
+        p = (uint8_t*) LLDP_NEIGHBOR_RAW(n) + n->rindex;
+        return p[1] + (((size_t) (p[0] & 1)) << 8);
+}
+
+static inline void* LLDP_NEIGHBOR_TLV_DATA(const sd_lldp_neighbor *n) {
+        return ((uint8_t*) LLDP_NEIGHBOR_RAW(n)) + n->rindex + 2;
+}
+
+extern const struct hash_ops lldp_neighbor_hash_ops;
+int lldp_neighbor_id_compare_func(const LLDPNeighborID *x, const LLDPNeighborID *y);
+int lldp_neighbor_prioq_compare_func(const void *a, const void *b);
+
+sd_lldp_neighbor *lldp_neighbor_unlink(sd_lldp_neighbor *n);
+sd_lldp_neighbor *lldp_neighbor_new(size_t raw_size);
+int lldp_neighbor_parse(sd_lldp_neighbor *n);
+void lldp_neighbor_start_ttl(sd_lldp_neighbor *n);
+bool lldp_neighbor_equal(const sd_lldp_neighbor *a, const sd_lldp_neighbor *b);
diff --git a/src/libsystemd-network/lldp-network.c b/src/libsystemd-network/lldp-network.c
new file mode 100644
index 0000000..9616cb6
--- /dev/null
+++ b/src/libsystemd-network/lldp-network.c
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <linux/filter.h>
+#include <netinet/if_ether.h>
+
+#include "fd-util.h"
+#include "lldp-network.h"
+#include "missing_network.h"
+#include "socket-util.h"
+
+int lldp_network_bind_raw_socket(int ifindex) {
+
+        static const struct sock_filter filter[] = {
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ethhdr, h_dest)),      /* A <- 4 bytes of destination MAC */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0180c200, 1, 0),                    /* A != 01:80:c2:00 */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                             /* drop packet */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_dest) + 4),  /* A <- remaining 2 bytes of destination MAC */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0000, 3, 0),                        /* A != 00:00 */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x0003, 2, 0),                        /* A != 00:03 */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0x000e, 1, 0),                        /* A != 00:0e */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                             /* drop packet */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ethhdr, h_proto)),     /* A <- protocol */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_LLDP, 1, 0),                /* A != ETHERTYPE_LLDP */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                             /* drop packet */
+                BPF_STMT(BPF_RET + BPF_K, (uint32_t) -1),                                 /* accept packet */
+        };
+
+        static const struct sock_fprog fprog = {
+                .len = ELEMENTSOF(filter),
+                .filter = (struct sock_filter*) filter,
+        };
+
+        struct packet_mreq mreq = {
+                .mr_ifindex = ifindex,
+                .mr_type = PACKET_MR_MULTICAST,
+                .mr_alen = ETH_ALEN,
+                .mr_address = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x00 }
+        };
+
+        union sockaddr_union saddrll = {
+                .ll.sll_family = AF_PACKET,
+                .ll.sll_ifindex = ifindex,
+        };
+
+        _cleanup_close_ int fd = -1;
+        int r;
+
+        assert(ifindex > 0);
+
+        fd = socket(AF_PACKET, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK,
+                    htobe16(ETHERTYPE_LLDP));
+        if (fd < 0)
+                return -errno;
+
+        r = setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
+        if (r < 0)
+                return -errno;
+
+        r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
+        if (r < 0)
+                return -errno;
+
+        mreq.mr_address[ETH_ALEN - 1] = 0x03;
+        r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
+        if (r < 0)
+                return -errno;
+
+        mreq.mr_address[ETH_ALEN - 1] = 0x0E;
+        r = setsockopt(fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
+        if (r < 0)
+                return -errno;
+
+        r = bind(fd, &saddrll.sa, sizeof(saddrll.ll));
+        if (r < 0)
+                return -errno;
+
+        return TAKE_FD(fd);
+}
diff --git a/src/libsystemd-network/lldp-network.h b/src/libsystemd-network/lldp-network.h
new file mode 100644
index 0000000..bc69b32
--- /dev/null
+++ b/src/libsystemd-network/lldp-network.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-event.h"
+
+int lldp_network_bind_raw_socket(int ifindex);
diff --git a/src/libsystemd-network/meson.build b/src/libsystemd-network/meson.build
new file mode 100644
index 0000000..604cfd9
--- /dev/null
+++ b/src/libsystemd-network/meson.build
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+sources = files('''
+        sd-dhcp-client.c
+        sd-dhcp-server.c
+        dhcp-client-internal.h
+        dhcp-network.c
+        dhcp-option.c
+        dhcp-packet.c
+        dhcp-internal.h
+        dhcp-server-internal.h
+        dhcp-protocol.h
+        dhcp-lease-internal.h
+        sd-dhcp-lease.c
+        sd-ipv4ll.c
+        sd-ipv4acd.c
+        arp-util.h
+        arp-util.c
+        network-internal.c
+        sd-ndisc.c
+        ndisc-internal.h
+        ndisc-router.h
+        ndisc-router.c
+        sd-radv.c
+        radv-internal.h
+        icmp6-util.h
+        icmp6-util.c
+        sd-dhcp6-client.c
+        dhcp6-internal.h
+        dhcp6-protocol.h
+        dhcp6-network.c
+        dhcp6-option.c
+        dhcp6-lease-internal.h
+        sd-dhcp6-lease.c
+        dhcp-identifier.h
+        dhcp-identifier.c
+        lldp-internal.h
+        lldp-network.h
+        lldp-network.c
+        lldp-neighbor.h
+        lldp-neighbor.c
+        sd-lldp.c
+'''.split())
+
+network_internal_h = files('network-internal.h')
+
+libsystemd_network = static_library(
+        'systemd-network',
+        sources,
+        network_internal_h,
+        include_directories : includes)
diff --git a/src/libsystemd-network/ndisc-internal.h b/src/libsystemd-network/ndisc-internal.h
new file mode 100644
index 0000000..65f9371
--- /dev/null
+++ b/src/libsystemd-network/ndisc-internal.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include "log.h"
+#include "time-util.h"
+
+#include "sd-ndisc.h"
+
+#define NDISC_ROUTER_SOLICITATION_INTERVAL (4U * USEC_PER_SEC)
+#define NDISC_MAX_ROUTER_SOLICITATION_INTERVAL (3600U * USEC_PER_SEC)
+#define NDISC_MAX_ROUTER_SOLICITATIONS 3U
+
+struct sd_ndisc {
+        unsigned n_ref;
+
+        int ifindex;
+        int fd;
+
+        sd_event *event;
+        int event_priority;
+
+        struct ether_addr mac_addr;
+        uint8_t hop_limit;
+        uint32_t mtu;
+
+        sd_event_source *recv_event_source;
+        sd_event_source *timeout_event_source;
+        sd_event_source *timeout_no_ra;
+
+        usec_t retransmit_time;
+
+        sd_ndisc_callback_t callback;
+        void *userdata;
+};
+
+#define log_ndisc_errno(error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "NDISC: " fmt, ##__VA_ARGS__)
+#define log_ndisc(fmt, ...) log_ndisc_errno(0, fmt, ##__VA_ARGS__)
+
+const char* ndisc_event_to_string(sd_ndisc_event e) _const_;
+sd_ndisc_event ndisc_event_from_string(const char *s) _pure_;
diff --git a/src/libsystemd-network/ndisc-router.c b/src/libsystemd-network/ndisc-router.c
new file mode 100644
index 0000000..3cb71db
--- /dev/null
+++ b/src/libsystemd-network/ndisc-router.c
@@ -0,0 +1,750 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/icmp6.h>
+
+#include "sd-ndisc.h"
+
+#include "alloc-util.h"
+#include "dns-domain.h"
+#include "hostname-util.h"
+#include "memory-util.h"
+#include "missing_network.h"
+#include "ndisc-internal.h"
+#include "ndisc-router.h"
+#include "strv.h"
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc_router, sd_ndisc_router, mfree);
+
+sd_ndisc_router *ndisc_router_new(size_t raw_size) {
+        sd_ndisc_router *rt;
+
+        rt = malloc0(ALIGN(sizeof(sd_ndisc_router)) + raw_size);
+        if (!rt)
+                return NULL;
+
+        rt->raw_size = raw_size;
+        rt->n_ref = 1;
+
+        return rt;
+}
+
+_public_ int sd_ndisc_router_from_raw(sd_ndisc_router **ret, const void *raw, size_t raw_size) {
+        _cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(raw || raw_size <= 0, -EINVAL);
+
+        rt = ndisc_router_new(raw_size);
+        if (!rt)
+                return -ENOMEM;
+
+        memcpy(NDISC_ROUTER_RAW(rt), raw, raw_size);
+        r = ndisc_router_parse(rt);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(rt);
+
+        return r;
+}
+
+_public_ int sd_ndisc_router_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret_addr, -EINVAL);
+
+        if (IN6_IS_ADDR_UNSPECIFIED(&rt->address))
+                return -ENODATA;
+
+        *ret_addr = rt->address;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_timestamp(sd_ndisc_router *rt, clockid_t clock, uint64_t *ret) {
+        assert_return(rt, -EINVAL);
+        assert_return(TRIPLE_TIMESTAMP_HAS_CLOCK(clock), -EOPNOTSUPP);
+        assert_return(clock_supported(clock), -EOPNOTSUPP);
+        assert_return(ret, -EINVAL);
+
+        if (!triple_timestamp_is_set(&rt->timestamp))
+                return -ENODATA;
+
+        *ret = triple_timestamp_by_clock(&rt->timestamp, clock);
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_raw(sd_ndisc_router *rt, const void **ret, size_t *size) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(size, -EINVAL);
+
+        *ret = NDISC_ROUTER_RAW(rt);
+        *size = rt->raw_size;
+
+        return 0;
+}
+
+int ndisc_router_parse(sd_ndisc_router *rt) {
+        struct nd_router_advert *a;
+        const uint8_t *p;
+        bool has_mtu = false, has_flag_extension = false;
+        size_t left;
+
+        assert(rt);
+
+        if (rt->raw_size < sizeof(struct nd_router_advert)) {
+                log_ndisc("Too small to be a router advertisement, ignoring.");
+                return -EBADMSG;
+        }
+
+        /* Router advertisement packets are neatly aligned to 64bit boundaries, hence we can access them directly */
+        a = NDISC_ROUTER_RAW(rt);
+
+        if (a->nd_ra_type != ND_ROUTER_ADVERT) {
+                log_ndisc("Received ND packet that is not a router advertisement, ignoring.");
+                return -EBADMSG;
+        }
+
+        if (a->nd_ra_code != 0) {
+                log_ndisc("Received ND packet with wrong RA code, ignoring.");
+                return -EBADMSG;
+        }
+
+        rt->hop_limit = a->nd_ra_curhoplimit;
+        rt->flags = a->nd_ra_flags_reserved; /* the first 8bit */
+        rt->lifetime = be16toh(a->nd_ra_router_lifetime);
+
+        rt->preference = (rt->flags >> 3) & 3;
+        if (!IN_SET(rt->preference, SD_NDISC_PREFERENCE_LOW, SD_NDISC_PREFERENCE_HIGH))
+                rt->preference = SD_NDISC_PREFERENCE_MEDIUM;
+
+        p = (const uint8_t*) NDISC_ROUTER_RAW(rt) + sizeof(struct nd_router_advert);
+        left = rt->raw_size - sizeof(struct nd_router_advert);
+
+        for (;;) {
+                uint8_t type;
+                size_t length;
+
+                if (left == 0)
+                        break;
+
+                if (left < 2) {
+                        log_ndisc("Option lacks header, ignoring datagram.");
+                        return -EBADMSG;
+                }
+
+                type = p[0];
+                length = p[1] * 8;
+
+                if (length == 0) {
+                        log_ndisc("Zero-length option, ignoring datagram.");
+                        return -EBADMSG;
+                }
+                if (left < length) {
+                        log_ndisc("Option truncated, ignoring datagram.");
+                        return -EBADMSG;
+                }
+
+                switch (type) {
+
+                case SD_NDISC_OPTION_PREFIX_INFORMATION:
+
+                        if (length != 4*8) {
+                                log_ndisc("Prefix option of invalid size, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        if (p[2] > 128) {
+                                log_ndisc("Bad prefix length, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        break;
+
+                case SD_NDISC_OPTION_MTU: {
+                        uint32_t m;
+
+                        if (has_mtu) {
+                                log_ndisc("MTU option specified twice, ignoring.");
+                                break;
+                        }
+
+                        if (length != 8) {
+                                log_ndisc("MTU option of invalid size, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        m = be32toh(*(uint32_t*) (p + 4));
+                        if (m >= IPV6_MIN_MTU) /* ignore invalidly small MTUs */
+                                rt->mtu = m;
+
+                        has_mtu = true;
+                        break;
+                }
+
+                case SD_NDISC_OPTION_ROUTE_INFORMATION:
+                        if (length < 1*8 || length > 3*8) {
+                                log_ndisc("Route information option of invalid size, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        if (p[2] > 128) {
+                                log_ndisc("Bad route prefix length, ignoring datagram.");
+                                return -EBADMSG;
+                        }
+
+                        break;
+
+                case SD_NDISC_OPTION_RDNSS:
+                        if (length < 3*8 || (length % (2*8)) != 1*8) {
+                                log_ndisc("RDNSS option has invalid size.");
+                                return -EBADMSG;
+                        }
+
+                        break;
+
+                case SD_NDISC_OPTION_FLAGS_EXTENSION:
+
+                        if (has_flag_extension) {
+                                log_ndisc("Flags extension option specified twice, ignoring.");
+                                break;
+                        }
+
+                        if (length < 1*8) {
+                                log_ndisc("Flags extension option has invalid size.");
+                                return -EBADMSG;
+                        }
+
+                        /* Add in the additional flags bits */
+                        rt->flags |=
+                                ((uint64_t) p[2] << 8) |
+                                ((uint64_t) p[3] << 16) |
+                                ((uint64_t) p[4] << 24) |
+                                ((uint64_t) p[5] << 32) |
+                                ((uint64_t) p[6] << 40) |
+                                ((uint64_t) p[7] << 48);
+
+                        has_flag_extension = true;
+                        break;
+
+                case SD_NDISC_OPTION_DNSSL:
+                        if (length < 2*8) {
+                                log_ndisc("DNSSL option has invalid size.");
+                                return -EBADMSG;
+                        }
+
+                        break;
+                }
+
+                p += length, left -= length;
+        }
+
+        rt->rindex = sizeof(struct nd_router_advert);
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_hop_limit(sd_ndisc_router *rt, uint8_t *ret) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        *ret = rt->hop_limit;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_flags(sd_ndisc_router *rt, uint64_t *ret_flags) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret_flags, -EINVAL);
+
+        *ret_flags = rt->flags;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_lifetime(sd_ndisc_router *rt, uint16_t *ret_lifetime) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret_lifetime, -EINVAL);
+
+        *ret_lifetime = rt->lifetime;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_preference(sd_ndisc_router *rt, unsigned *ret) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        *ret = rt->preference;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_get_mtu(sd_ndisc_router *rt, uint32_t *ret) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (rt->mtu <= 0)
+                return -ENODATA;
+
+        *ret = rt->mtu;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_option_rewind(sd_ndisc_router *rt) {
+        assert_return(rt, -EINVAL);
+
+        assert(rt->raw_size >= sizeof(struct nd_router_advert));
+        rt->rindex = sizeof(struct nd_router_advert);
+
+        return rt->rindex < rt->raw_size;
+}
+
+_public_ int sd_ndisc_router_option_next(sd_ndisc_router *rt) {
+        size_t length;
+
+        assert_return(rt, -EINVAL);
+
+        if (rt->rindex == rt->raw_size) /* EOF */
+                return -ESPIPE;
+
+        if (rt->rindex + 2 > rt->raw_size) /* Truncated message */
+                return -EBADMSG;
+
+        length = NDISC_ROUTER_OPTION_LENGTH(rt);
+        if (rt->rindex + length > rt->raw_size)
+                return -EBADMSG;
+
+        rt->rindex += length;
+        return rt->rindex < rt->raw_size;
+}
+
+_public_ int sd_ndisc_router_option_get_type(sd_ndisc_router *rt, uint8_t *ret) {
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (rt->rindex == rt->raw_size) /* EOF */
+                return -ESPIPE;
+
+        if (rt->rindex + 2 > rt->raw_size) /* Truncated message */
+                return -EBADMSG;
+
+        *ret = NDISC_ROUTER_OPTION_TYPE(rt);
+        return 0;
+}
+
+_public_ int sd_ndisc_router_option_is_type(sd_ndisc_router *rt, uint8_t type) {
+        uint8_t k;
+        int r;
+
+        assert_return(rt, -EINVAL);
+
+        r = sd_ndisc_router_option_get_type(rt, &k);
+        if (r < 0)
+                return r;
+
+        return type == k;
+}
+
+_public_ int sd_ndisc_router_option_get_raw(sd_ndisc_router *rt, const void **ret, size_t *size) {
+        size_t length;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(size, -EINVAL);
+
+        /* Note that this returns the full option, including the option header */
+
+        if (rt->rindex + 2 > rt->raw_size)
+                return -EBADMSG;
+
+        length = NDISC_ROUTER_OPTION_LENGTH(rt);
+        if (rt->rindex + length > rt->raw_size)
+                return -EBADMSG;
+
+        *ret = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex;
+        *size = length;
+
+        return 0;
+}
+
+static int get_prefix_info(sd_ndisc_router *rt, struct nd_opt_prefix_info **ret) {
+        struct nd_opt_prefix_info *ri;
+        size_t length;
+        int r;
+
+        assert(rt);
+        assert(ret);
+
+        r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_PREFIX_INFORMATION);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EMEDIUMTYPE;
+
+        length = NDISC_ROUTER_OPTION_LENGTH(rt);
+        if (length != sizeof(struct nd_opt_prefix_info))
+                return -EBADMSG;
+
+        ri = (struct nd_opt_prefix_info*) ((uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex);
+        if (ri->nd_opt_pi_prefix_len > 128)
+                return -EBADMSG;
+
+        *ret = ri;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_prefix_get_valid_lifetime(sd_ndisc_router *rt, uint32_t *ret) {
+        struct nd_opt_prefix_info *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_prefix_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret = be32toh(ri->nd_opt_pi_valid_time);
+        return 0;
+}
+
+_public_ int sd_ndisc_router_prefix_get_preferred_lifetime(sd_ndisc_router *rt, uint32_t *ret) {
+        struct nd_opt_prefix_info *pi;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_prefix_info(rt, &pi);
+        if (r < 0)
+                return r;
+
+        *ret = be32toh(pi->nd_opt_pi_preferred_time);
+        return 0;
+}
+
+_public_ int sd_ndisc_router_prefix_get_flags(sd_ndisc_router *rt, uint8_t *ret) {
+        struct nd_opt_prefix_info *pi;
+        uint8_t flags;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_prefix_info(rt, &pi);
+        if (r < 0)
+                return r;
+
+        flags = pi->nd_opt_pi_flags_reserved;
+
+        if ((flags & ND_OPT_PI_FLAG_AUTO) && (pi->nd_opt_pi_prefix_len != 64)) {
+                log_ndisc("Invalid prefix length, ignoring prefix for stateless autoconfiguration.");
+                flags &= ~ND_OPT_PI_FLAG_AUTO;
+        }
+
+        *ret = flags;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_prefix_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr) {
+        struct nd_opt_prefix_info *pi;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret_addr, -EINVAL);
+
+        r = get_prefix_info(rt, &pi);
+        if (r < 0)
+                return r;
+
+        *ret_addr = pi->nd_opt_pi_prefix;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_prefix_get_prefixlen(sd_ndisc_router *rt, unsigned *ret) {
+        struct nd_opt_prefix_info *pi;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_prefix_info(rt, &pi);
+        if (r < 0)
+                return r;
+
+        if (pi->nd_opt_pi_prefix_len > 128)
+                return -EBADMSG;
+
+        *ret = pi->nd_opt_pi_prefix_len;
+        return 0;
+}
+
+static int get_route_info(sd_ndisc_router *rt, uint8_t **ret) {
+        uint8_t *ri;
+        size_t length;
+        int r;
+
+        assert(rt);
+        assert(ret);
+
+        r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_ROUTE_INFORMATION);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EMEDIUMTYPE;
+
+        length = NDISC_ROUTER_OPTION_LENGTH(rt);
+        if (length < 1*8 || length > 3*8)
+                return -EBADMSG;
+
+        ri = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex;
+
+        if (ri[2] > 128)
+                return -EBADMSG;
+
+        *ret = ri;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_route_get_lifetime(sd_ndisc_router *rt, uint32_t *ret) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_route_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret = be32toh(*(uint32_t*) (ri + 4));
+        return 0;
+}
+
+_public_ int sd_ndisc_router_route_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret_addr, -EINVAL);
+
+        r = get_route_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        zero(*ret_addr);
+        memcpy(ret_addr, ri + 8, NDISC_ROUTER_OPTION_LENGTH(rt) - 8);
+
+        return 0;
+}
+
+_public_ int sd_ndisc_router_route_get_prefixlen(sd_ndisc_router *rt, unsigned *ret) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_route_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret = ri[2];
+        return 0;
+}
+
+_public_ int sd_ndisc_router_route_get_preference(sd_ndisc_router *rt, unsigned *ret) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_route_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret = (ri[3] >> 3) & 3;
+        if (!IN_SET(*ret, SD_NDISC_PREFERENCE_LOW, SD_NDISC_PREFERENCE_HIGH))
+                *ret = SD_NDISC_PREFERENCE_MEDIUM;
+
+        return 0;
+}
+
+static int get_rdnss_info(sd_ndisc_router *rt, uint8_t **ret) {
+        size_t length;
+        int r;
+
+        assert(rt);
+        assert(ret);
+
+        r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_RDNSS);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EMEDIUMTYPE;
+
+        length = NDISC_ROUTER_OPTION_LENGTH(rt);
+        if (length < 3*8 || (length % (2*8)) != 1*8)
+                return -EBADMSG;
+
+        *ret = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_rdnss_get_addresses(sd_ndisc_router *rt, const struct in6_addr **ret) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_rdnss_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret = (const struct in6_addr*) (ri + 8);
+        return (NDISC_ROUTER_OPTION_LENGTH(rt) - 8) / 16;
+}
+
+_public_ int sd_ndisc_router_rdnss_get_lifetime(sd_ndisc_router *rt, uint32_t *ret) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_rdnss_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret = be32toh(*(uint32_t*) (ri + 4));
+        return 0;
+}
+
+static int get_dnssl_info(sd_ndisc_router *rt, uint8_t **ret) {
+        size_t length;
+        int r;
+
+        assert(rt);
+        assert(ret);
+
+        r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_DNSSL);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EMEDIUMTYPE;
+
+        length = NDISC_ROUTER_OPTION_LENGTH(rt);
+        if (length < 2*8)
+                return -EBADMSG;
+
+        *ret = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex;
+        return 0;
+}
+
+_public_ int sd_ndisc_router_dnssl_get_domains(sd_ndisc_router *rt, char ***ret) {
+        _cleanup_strv_free_ char **l = NULL;
+        _cleanup_free_ char *e = NULL;
+        size_t allocated = 0, n = 0, left;
+        uint8_t *ri, *p;
+        bool first = true;
+        int r;
+        unsigned k = 0;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = get_dnssl_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        p = ri + 8;
+        left = NDISC_ROUTER_OPTION_LENGTH(rt) - 8;
+
+        for (;;) {
+                if (left == 0) {
+
+                        if (n > 0) /* Not properly NUL terminated */
+                                return -EBADMSG;
+
+                        break;
+                }
+
+                if (*p == 0) {
+                        /* Found NUL termination */
+
+                        if (n > 0) {
+                                _cleanup_free_ char *normalized = NULL;
+
+                                e[n] = 0;
+                                r = dns_name_normalize(e, 0, &normalized);
+                                if (r < 0)
+                                        return r;
+
+                                /* Ignore the root domain name or "localhost" and friends */
+                                if (!is_localhost(normalized) &&
+                                    !dns_name_is_root(normalized)) {
+
+                                        if (strv_push(&l, normalized) < 0)
+                                                return -ENOMEM;
+
+                                        normalized = NULL;
+                                        k++;
+                                }
+                        }
+
+                        n = 0;
+                        first = true;
+                        p++, left--;
+                        continue;
+                }
+
+                /* Check for compression (which is not allowed) */
+                if (*p > 63)
+                        return -EBADMSG;
+
+                if (1U + *p + 1U > left)
+                        return -EBADMSG;
+
+                if (!GREEDY_REALLOC(e, allocated, n + !first + DNS_LABEL_ESCAPED_MAX + 1U))
+                        return -ENOMEM;
+
+                if (first)
+                        first = false;
+                else
+                        e[n++] = '.';
+
+                r = dns_label_escape((char*) p+1, *p, e + n, DNS_LABEL_ESCAPED_MAX);
+                if (r < 0)
+                        return r;
+
+                n += r;
+
+                left -= 1 + *p;
+                p += 1 + *p;
+        }
+
+        if (strv_isempty(l)) {
+                *ret = NULL;
+                return 0;
+        }
+
+        *ret = TAKE_PTR(l);
+
+        return k;
+}
+
+_public_ int sd_ndisc_router_dnssl_get_lifetime(sd_ndisc_router *rt, uint32_t *ret_sec) {
+        uint8_t *ri;
+        int r;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret_sec, -EINVAL);
+
+        r = get_dnssl_info(rt, &ri);
+        if (r < 0)
+                return r;
+
+        *ret_sec = be32toh(*(uint32_t*) (ri + 4));
+        return 0;
+}
diff --git a/src/libsystemd-network/ndisc-router.h b/src/libsystemd-network/ndisc-router.h
new file mode 100644
index 0000000..cb3a564
--- /dev/null
+++ b/src/libsystemd-network/ndisc-router.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include "sd-ndisc.h"
+
+#include "time-util.h"
+
+struct sd_ndisc_router {
+        unsigned n_ref;
+
+        triple_timestamp timestamp;
+        struct in6_addr address;
+
+        /* The raw packet size. The data is appended to the object, accessible via NDIS_ROUTER_RAW() */
+        size_t raw_size;
+
+        /* The current read index for the iterative option interface */
+        size_t rindex;
+
+        uint64_t flags;
+        unsigned preference;
+        uint16_t lifetime;
+
+        uint8_t hop_limit;
+        uint32_t mtu;
+};
+
+static inline void* NDISC_ROUTER_RAW(const sd_ndisc_router *rt) {
+        return (uint8_t*) rt + ALIGN(sizeof(sd_ndisc_router));
+}
+
+static inline void *NDISC_ROUTER_OPTION_DATA(const sd_ndisc_router *rt) {
+        return ((uint8_t*) NDISC_ROUTER_RAW(rt)) + rt->rindex;
+}
+
+static inline uint8_t NDISC_ROUTER_OPTION_TYPE(const sd_ndisc_router *rt) {
+        return ((uint8_t*) NDISC_ROUTER_OPTION_DATA(rt))[0];
+}
+static inline size_t NDISC_ROUTER_OPTION_LENGTH(const sd_ndisc_router *rt) {
+        return ((uint8_t*) NDISC_ROUTER_OPTION_DATA(rt))[1] * 8;
+}
+
+sd_ndisc_router *ndisc_router_new(size_t raw_size);
+int ndisc_router_parse(sd_ndisc_router *rt);
diff --git a/src/libsystemd-network/network-internal.c b/src/libsystemd-network/network-internal.c
new file mode 100644
index 0000000..e4a0741
--- /dev/null
+++ b/src/libsystemd-network/network-internal.c
@@ -0,0 +1,886 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <arpa/inet.h>
+#include <linux/if.h>
+#include <netinet/ether.h>
+
+#include "sd-id128.h"
+#include "sd-ndisc.h"
+
+#include "alloc-util.h"
+#include "arphrd-list.h"
+#include "condition.h"
+#include "conf-parser.h"
+#include "device-util.h"
+#include "dhcp-lease-internal.h"
+#include "env-util.h"
+#include "ether-addr-util.h"
+#include "hexdecoct.h"
+#include "log.h"
+#include "network-internal.h"
+#include "parse-util.h"
+#include "siphash24.h"
+#include "socket-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "utf8.h"
+#include "util.h"
+
+const char *net_get_name_persistent(sd_device *device) {
+        const char *name, *field;
+
+        assert(device);
+
+        /* fetch some persistent data unique (on this machine) to this device */
+        FOREACH_STRING(field, "ID_NET_NAME_ONBOARD", "ID_NET_NAME_SLOT", "ID_NET_NAME_PATH", "ID_NET_NAME_MAC")
+                if (sd_device_get_property_value(device, field, &name) >= 0)
+                        return name;
+
+        return NULL;
+}
+
+#define HASH_KEY SD_ID128_MAKE(d3,1e,48,fa,90,fe,4b,4c,9d,af,d5,d7,a1,b1,2e,8a)
+
+int net_get_unique_predictable_data(sd_device *device, bool use_sysname, uint64_t *result) {
+        size_t l, sz = 0;
+        const char *name;
+        int r;
+        uint8_t *v;
+
+        assert(device);
+
+        /* net_get_name_persistent() will return one of the device names based on stable information about
+         * the device. If this is not available, we fall back to using the actual device name. */
+        name = net_get_name_persistent(device);
+        if (!name && use_sysname)
+                (void) sd_device_get_sysname(device, &name);
+        if (!name)
+                return log_device_debug_errno(device, SYNTHETIC_ERRNO(ENODATA),
+                                              "No stable identifying information found");
+
+        log_device_debug(device, "Using \"%s\" as stable identifying information", name);
+        l = strlen(name);
+        sz = sizeof(sd_id128_t) + l;
+        v = newa(uint8_t, sz);
+
+        /* Fetch some persistent data unique to this machine */
+        r = sd_id128_get_machine((sd_id128_t*) v);
+        if (r < 0)
+                 return r;
+        memcpy(v + sizeof(sd_id128_t), name, l);
+
+        /* Let's hash the machine ID plus the device name. We use
+         * a fixed, but originally randomly created hash key here. */
+        *result = htole64(siphash24(v, sz, HASH_KEY.bytes));
+        return 0;
+}
+
+static bool net_condition_test_strv(char * const *patterns, const char *string) {
+        char * const *p;
+        bool match = false, has_positive_rule = false;
+
+        if (strv_isempty(patterns))
+                return true;
+
+        STRV_FOREACH(p, patterns) {
+                const char *q = *p;
+                bool invert;
+
+                invert = *q == '!';
+                q += invert;
+
+                if (!invert)
+                        has_positive_rule = true;
+
+                if (string && fnmatch(q, string, 0) == 0) {
+                        if (invert)
+                                return false;
+                        else
+                                match = true;
+                }
+        }
+
+        return has_positive_rule ? match : true;
+}
+
+static bool net_condition_test_ifname(char * const *patterns, const char *ifname, char * const *alternative_names) {
+        if (net_condition_test_strv(patterns, ifname))
+                return true;
+
+        char * const *p;
+        STRV_FOREACH(p, alternative_names)
+                if (net_condition_test_strv(patterns, *p))
+                        return true;
+
+        return false;
+}
+
+static int net_condition_test_property(char * const *match_property, sd_device *device) {
+        char * const *p;
+
+        if (strv_isempty(match_property))
+                return true;
+
+        STRV_FOREACH(p, match_property) {
+                _cleanup_free_ char *key = NULL;
+                const char *val, *dev_val;
+                bool invert, v;
+
+                invert = **p == '!';
+
+                val = strchr(*p + invert, '=');
+                if (!val)
+                        return -EINVAL;
+
+                key = strndup(*p + invert, val - *p - invert);
+                if (!key)
+                        return -ENOMEM;
+
+                val++;
+
+                v = device &&
+                        sd_device_get_property_value(device, key, &dev_val) >= 0 &&
+                        fnmatch(val, dev_val, 0) == 0;
+
+                if (invert ? v : !v)
+                        return false;
+        }
+
+        return true;
+}
+
+static const char *const wifi_iftype_table[NL80211_IFTYPE_MAX+1] = {
+        [NL80211_IFTYPE_ADHOC] = "ad-hoc",
+        [NL80211_IFTYPE_STATION] = "station",
+        [NL80211_IFTYPE_AP] = "ap",
+        [NL80211_IFTYPE_AP_VLAN] = "ap-vlan",
+        [NL80211_IFTYPE_WDS] = "wds",
+        [NL80211_IFTYPE_MONITOR] = "monitor",
+        [NL80211_IFTYPE_MESH_POINT] = "mesh-point",
+        [NL80211_IFTYPE_P2P_CLIENT] = "p2p-client",
+        [NL80211_IFTYPE_P2P_GO] = "p2p-go",
+        [NL80211_IFTYPE_P2P_DEVICE] = "p2p-device",
+        [NL80211_IFTYPE_OCB] = "ocb",
+        [NL80211_IFTYPE_NAN] = "nan",
+};
+
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(wifi_iftype, enum nl80211_iftype);
+
+char *link_get_type_string(unsigned short iftype, sd_device *device) {
+        const char *t, *devtype;
+        char *p;
+
+        if (device &&
+            sd_device_get_devtype(device, &devtype) >= 0 &&
+            !isempty(devtype))
+                return strdup(devtype);
+
+        t = arphrd_to_name(iftype);
+        if (!t)
+                return NULL;
+
+        p = strdup(t);
+        if (!p)
+                return NULL;
+
+        ascii_strlower(p);
+        return p;
+}
+
+bool net_match_config(Set *match_mac,
+                      Set *match_permanent_mac,
+                      char * const *match_paths,
+                      char * const *match_drivers,
+                      char * const *match_iftypes,
+                      char * const *match_names,
+                      char * const *match_property,
+                      char * const *match_wifi_iftype,
+                      char * const *match_ssid,
+                      Set *match_bssid,
+                      sd_device *device,
+                      const struct ether_addr *dev_mac,
+                      const struct ether_addr *dev_permanent_mac,
+                      const char *dev_driver,
+                      unsigned short dev_iftype,
+                      const char *dev_name,
+                      char * const *alternative_names,
+                      enum nl80211_iftype dev_wifi_iftype,
+                      const char *dev_ssid,
+                      const struct ether_addr *dev_bssid) {
+
+        _cleanup_free_ char *dev_iftype_str;
+        const char *dev_path = NULL;
+
+        dev_iftype_str = link_get_type_string(dev_iftype, device);
+
+        if (device) {
+                const char *mac_str;
+
+                (void) sd_device_get_property_value(device, "ID_PATH", &dev_path);
+                if (!dev_driver)
+                        (void) sd_device_get_property_value(device, "ID_NET_DRIVER", &dev_driver);
+                if (!dev_name)
+                        (void) sd_device_get_sysname(device, &dev_name);
+                if (!dev_mac &&
+                    sd_device_get_sysattr_value(device, "address", &mac_str) >= 0)
+                        dev_mac = ether_aton(mac_str);
+        }
+
+        if (match_mac && (!dev_mac || !set_contains(match_mac, dev_mac)))
+                return false;
+
+        if (match_permanent_mac &&
+            (!dev_permanent_mac ||
+             ether_addr_is_null(dev_permanent_mac) ||
+             !set_contains(match_permanent_mac, dev_permanent_mac)))
+                return false;
+
+        if (!net_condition_test_strv(match_paths, dev_path))
+                return false;
+
+        if (!net_condition_test_strv(match_drivers, dev_driver))
+                return false;
+
+        if (!net_condition_test_strv(match_iftypes, dev_iftype_str))
+                return false;
+
+        if (!net_condition_test_ifname(match_names, dev_name, alternative_names))
+                return false;
+
+        if (!net_condition_test_property(match_property, device))
+                return false;
+
+        if (!net_condition_test_strv(match_wifi_iftype, wifi_iftype_to_string(dev_wifi_iftype)))
+                return false;
+
+        if (!net_condition_test_strv(match_ssid, dev_ssid))
+                return false;
+
+        if (match_bssid && (!dev_bssid || !set_contains(match_bssid, dev_bssid)))
+                return false;
+
+        return true;
+}
+
+int config_parse_net_condition(const char *unit,
+                               const char *filename,
+                               unsigned line,
+                               const char *section,
+                               unsigned section_line,
+                               const char *lvalue,
+                               int ltype,
+                               const char *rvalue,
+                               void *data,
+                               void *userdata) {
+
+        ConditionType cond = ltype;
+        Condition **list = data, *c;
+        bool negate;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                *list = condition_free_list_type(*list, cond);
+                return 0;
+        }
+
+        negate = rvalue[0] == '!';
+        if (negate)
+                rvalue++;
+
+        c = condition_new(cond, rvalue, false, negate);
+        if (!c)
+                return log_oom();
+
+        /* Drop previous assignment. */
+        *list = condition_free_list_type(*list, cond);
+
+        LIST_PREPEND(conditions, *list, c);
+        return 0;
+}
+
+int config_parse_match_strv(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        const char *p = rvalue;
+        char ***sv = data;
+        bool invert;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                *sv = strv_free(*sv);
+                return 0;
+        }
+
+        invert = *p == '!';
+        p += invert;
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL, *k = NULL;
+
+                r = extract_first_word(&p, &word, NULL, EXTRACT_UNQUOTE|EXTRACT_RETAIN_ESCAPE);
+                if (r == 0)
+                        return 0;
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Invalid syntax, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                if (invert) {
+                        k = strjoin("!", word);
+                        if (!k)
+                                return log_oom();
+                } else
+                        k = TAKE_PTR(word);
+
+                r = strv_consume(sv, TAKE_PTR(k));
+                if (r < 0)
+                        return log_oom();
+        }
+}
+
+int config_parse_match_ifnames(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        const char *p = rvalue;
+        char ***sv = data;
+        bool invert;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        invert = *p == '!';
+        p += invert;
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL, *k = NULL;
+
+                r = extract_first_word(&p, &word, NULL, 0);
+                if (r == 0)
+                        return 0;
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0,
+                                   "Failed to parse interface name list: %s", rvalue);
+                        return 0;
+                }
+
+                if (!ifname_valid_full(word, ltype)) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0,
+                                   "Interface name is not valid or too long, ignoring assignment: %s", word);
+                        continue;
+                }
+
+                if (invert) {
+                        k = strjoin("!", word);
+                        if (!k)
+                                return log_oom();
+                } else
+                        k = TAKE_PTR(word);
+
+                r = strv_consume(sv, TAKE_PTR(k));
+                if (r < 0)
+                        return log_oom();
+        }
+}
+
+int config_parse_match_property(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        const char *p = rvalue;
+        char ***sv = data;
+        bool invert;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        invert = *p == '!';
+        p += invert;
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL, *k = NULL;
+
+                r = extract_first_word(&p, &word, NULL, EXTRACT_CUNESCAPE|EXTRACT_UNQUOTE);
+                if (r == 0)
+                        return 0;
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0,
+                                   "Invalid syntax, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                if (!env_assignment_is_valid(word)) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0,
+                                   "Invalid property or value, ignoring assignment: %s", word);
+                        continue;
+                }
+
+                if (invert) {
+                        k = strjoin("!", word);
+                        if (!k)
+                                return log_oom();
+                } else
+                        k = TAKE_PTR(word);
+
+                r = strv_consume(sv, TAKE_PTR(k));
+                if (r < 0)
+                        return log_oom();
+        }
+}
+
+int config_parse_ifalias(const char *unit,
+                         const char *filename,
+                         unsigned line,
+                         const char *section,
+                         unsigned section_line,
+                         const char *lvalue,
+                         int ltype,
+                         const char *rvalue,
+                         void *data,
+                         void *userdata) {
+
+        char **s = data;
+        _cleanup_free_ char *n = NULL;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        n = strdup(rvalue);
+        if (!n)
+                return log_oom();
+
+        if (!ascii_is_valid(n) || strlen(n) >= IFALIASZ) {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Interface alias is not ASCII clean or is too long, ignoring assignment: %s", rvalue);
+                return 0;
+        }
+
+        if (isempty(n))
+                *s = mfree(*s);
+        else
+                free_and_replace(*s, n);
+
+        return 0;
+}
+
+int config_parse_hwaddr(const char *unit,
+                        const char *filename,
+                        unsigned line,
+                        const char *section,
+                        unsigned section_line,
+                        const char *lvalue,
+                        int ltype,
+                        const char *rvalue,
+                        void *data,
+                        void *userdata) {
+
+        _cleanup_free_ struct ether_addr *n = NULL;
+        struct ether_addr **hwaddr = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        n = new0(struct ether_addr, 1);
+        if (!n)
+                return log_oom();
+
+        r = ether_addr_from_string(rvalue, n);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r, "Not a valid MAC address, ignoring assignment: %s", rvalue);
+                return 0;
+        }
+
+        free_and_replace(*hwaddr, n);
+
+        return 0;
+}
+
+int config_parse_hwaddrs(const char *unit,
+                         const char *filename,
+                         unsigned line,
+                         const char *section,
+                         unsigned section_line,
+                         const char *lvalue,
+                         int ltype,
+                         const char *rvalue,
+                         void *data,
+                         void *userdata) {
+
+        _cleanup_set_free_free_ Set *s = NULL;
+        const char *p = rvalue;
+        Set **hwaddrs = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                /* Empty assignment resets the list */
+                *hwaddrs = set_free_free(*hwaddrs);
+                return 0;
+        }
+
+        s = set_new(&ether_addr_hash_ops);
+        if (!s)
+                return log_oom();
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL;
+                _cleanup_free_ struct ether_addr *n = NULL;
+
+                r = extract_first_word(&p, &word, NULL, 0);
+                if (r == 0)
+                        break;
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_WARNING, filename, line, r, "Invalid syntax, ignoring: %s", rvalue);
+                        return 0;
+                }
+
+                n = new(struct ether_addr, 1);
+                if (!n)
+                        return log_oom();
+
+                r = ether_addr_from_string(word, n);
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, 0, "Not a valid MAC address, ignoring: %s", word);
+                        continue;
+                }
+
+                r = set_put(s, n);
+                if (r < 0)
+                        return log_oom();
+                if (r > 0)
+                        n = NULL; /* avoid cleanup */
+        }
+
+        r = set_ensure_allocated(hwaddrs, &ether_addr_hash_ops);
+        if (r < 0)
+                return log_oom();
+
+        r = set_move(*hwaddrs, s);
+        if (r < 0)
+                return log_oom();
+
+        return 0;
+}
+
+int config_parse_bridge_port_priority(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        uint16_t i;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        r = safe_atou16(rvalue, &i);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r,
+                           "Failed to parse bridge port priority, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        if (i > LINK_BRIDGE_PORT_PRIORITY_MAX) {
+                log_syntax(unit, LOG_ERR, filename, line, r,
+                           "Bridge port priority is larger than maximum %u, ignoring: %s", LINK_BRIDGE_PORT_PRIORITY_MAX, rvalue);
+                return 0;
+        }
+
+        *((uint16_t *)data) = i;
+
+        return 0;
+}
+
+size_t serialize_in_addrs(FILE *f,
+                          const struct in_addr *addresses,
+                          size_t size,
+                          bool *with_leading_space,
+                          bool (*predicate)(const struct in_addr *addr)) {
+        assert(f);
+        assert(addresses);
+
+        size_t count = 0;
+        bool _space = false;
+        if (!with_leading_space)
+                with_leading_space = &_space;
+
+        for (size_t i = 0; i < size; i++) {
+                char sbuf[INET_ADDRSTRLEN];
+
+                if (predicate && !predicate(&addresses[i]))
+                        continue;
+
+                if (*with_leading_space)
+                        fputc(' ', f);
+                fputs(inet_ntop(AF_INET, &addresses[i], sbuf, sizeof(sbuf)), f);
+                count++;
+                *with_leading_space = true;
+        }
+
+        return count;
+}
+
+int deserialize_in_addrs(struct in_addr **ret, const char *string) {
+        _cleanup_free_ struct in_addr *addresses = NULL;
+        int size = 0;
+
+        assert(ret);
+        assert(string);
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL;
+                struct in_addr *new_addresses;
+                int r;
+
+                r = extract_first_word(&string, &word, NULL, 0);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                new_addresses = reallocarray(addresses, size + 1, sizeof(struct in_addr));
+                if (!new_addresses)
+                        return -ENOMEM;
+                else
+                        addresses = new_addresses;
+
+                r = inet_pton(AF_INET, word, &(addresses[size]));
+                if (r <= 0)
+                        continue;
+
+                size++;
+        }
+
+        *ret = size > 0 ? TAKE_PTR(addresses) : NULL;
+
+        return size;
+}
+
+void serialize_in6_addrs(FILE *f, const struct in6_addr *addresses, size_t size, bool *with_leading_space) {
+        assert(f);
+        assert(addresses);
+        assert(size);
+
+        bool _space = false;
+        if (!with_leading_space)
+                with_leading_space = &_space;
+
+        for (size_t i = 0; i < size; i++) {
+                char buffer[INET6_ADDRSTRLEN];
+
+                if (*with_leading_space)
+                        fputc(' ', f);
+                fputs(inet_ntop(AF_INET6, addresses+i, buffer, sizeof(buffer)), f);
+                *with_leading_space = true;
+        }
+}
+
+int deserialize_in6_addrs(struct in6_addr **ret, const char *string) {
+        _cleanup_free_ struct in6_addr *addresses = NULL;
+        int size = 0;
+
+        assert(ret);
+        assert(string);
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL;
+                struct in6_addr *new_addresses;
+                int r;
+
+                r = extract_first_word(&string, &word, NULL, 0);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                new_addresses = reallocarray(addresses, size + 1, sizeof(struct in6_addr));
+                if (!new_addresses)
+                        return -ENOMEM;
+                else
+                        addresses = new_addresses;
+
+                r = inet_pton(AF_INET6, word, &(addresses[size]));
+                if (r <= 0)
+                        continue;
+
+                size++;
+        }
+
+        *ret = TAKE_PTR(addresses);
+
+        return size;
+}
+
+void serialize_dhcp_routes(FILE *f, const char *key, sd_dhcp_route **routes, size_t size) {
+        assert(f);
+        assert(key);
+        assert(routes);
+        assert(size);
+
+        fprintf(f, "%s=", key);
+
+        for (size_t i = 0; i < size; i++) {
+                char sbuf[INET_ADDRSTRLEN];
+                struct in_addr dest, gw;
+                uint8_t length;
+
+                assert_se(sd_dhcp_route_get_destination(routes[i], &dest) >= 0);
+                assert_se(sd_dhcp_route_get_gateway(routes[i], &gw) >= 0);
+                assert_se(sd_dhcp_route_get_destination_prefix_length(routes[i], &length) >= 0);
+
+                fprintf(f, "%s/%" PRIu8, inet_ntop(AF_INET, &dest, sbuf, sizeof sbuf), length);
+                fprintf(f, ",%s%s", inet_ntop(AF_INET, &gw, sbuf, sizeof sbuf), i < size - 1 ? " ": "");
+        }
+
+        fputs("\n", f);
+}
+
+int deserialize_dhcp_routes(struct sd_dhcp_route **ret, size_t *ret_size, size_t *ret_allocated, const char *string) {
+        _cleanup_free_ struct sd_dhcp_route *routes = NULL;
+        size_t size = 0, allocated = 0;
+
+        assert(ret);
+        assert(ret_size);
+        assert(ret_allocated);
+        assert(string);
+
+         /* WORD FORMAT: dst_ip/dst_prefixlen,gw_ip */
+        for (;;) {
+                _cleanup_free_ char *word = NULL;
+                char *tok, *tok_end;
+                unsigned n;
+                int r;
+
+                r = extract_first_word(&string, &word, NULL, 0);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                if (!GREEDY_REALLOC(routes, allocated, size + 1))
+                        return -ENOMEM;
+
+                tok = word;
+
+                /* get the subnet */
+                tok_end = strchr(tok, '/');
+                if (!tok_end)
+                        continue;
+                *tok_end = '\0';
+
+                r = inet_aton(tok, &routes[size].dst_addr);
+                if (r == 0)
+                        continue;
+
+                tok = tok_end + 1;
+
+                /* get the prefixlen */
+                tok_end = strchr(tok, ',');
+                if (!tok_end)
+                        continue;
+
+                *tok_end = '\0';
+
+                r = safe_atou(tok, &n);
+                if (r < 0 || n > 32)
+                        continue;
+
+                routes[size].dst_prefixlen = (uint8_t) n;
+                tok = tok_end + 1;
+
+                /* get the gateway */
+                r = inet_aton(tok, &routes[size].gw_addr);
+                if (r == 0)
+                        continue;
+
+                size++;
+        }
+
+        *ret_size = size;
+        *ret_allocated = allocated;
+        *ret = TAKE_PTR(routes);
+
+        return 0;
+}
+
+int serialize_dhcp_option(FILE *f, const char *key, const void *data, size_t size) {
+        _cleanup_free_ char *hex_buf = NULL;
+
+        assert(f);
+        assert(key);
+        assert(data);
+
+        hex_buf = hexmem(data, size);
+        if (!hex_buf)
+                return -ENOMEM;
+
+        fprintf(f, "%s=%s\n", key, hex_buf);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/network-internal.h b/src/libsystemd-network/network-internal.h
new file mode 100644
index 0000000..5dae5ab
--- /dev/null
+++ b/src/libsystemd-network/network-internal.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <linux/nl80211.h>
+#include <stdbool.h>
+
+#include "sd-device.h"
+#include "sd-dhcp-lease.h"
+
+#include "conf-parser.h"
+#include "set.h"
+#include "strv.h"
+
+#define LINK_BRIDGE_PORT_PRIORITY_INVALID 128
+#define LINK_BRIDGE_PORT_PRIORITY_MAX 63
+
+char *link_get_type_string(unsigned short iftype, sd_device *device);
+bool net_match_config(Set *match_mac,
+                      Set *match_permanent_mac,
+                      char * const *match_paths,
+                      char * const *match_drivers,
+                      char * const *match_iftypes,
+                      char * const *match_names,
+                      char * const *match_property,
+                      char * const *match_wifi_iftype,
+                      char * const *match_ssid,
+                      Set *match_bssid,
+                      sd_device *device,
+                      const struct ether_addr *dev_mac,
+                      const struct ether_addr *dev_permanent_mac,
+                      const char *dev_driver,
+                      unsigned short dev_iftype,
+                      const char *dev_name,
+                      char * const *alternative_names,
+                      enum nl80211_iftype dev_wifi_iftype,
+                      const char *dev_ssid,
+                      const struct ether_addr *dev_bssid);
+
+CONFIG_PARSER_PROTOTYPE(config_parse_net_condition);
+CONFIG_PARSER_PROTOTYPE(config_parse_hwaddr);
+CONFIG_PARSER_PROTOTYPE(config_parse_hwaddrs);
+CONFIG_PARSER_PROTOTYPE(config_parse_match_strv);
+CONFIG_PARSER_PROTOTYPE(config_parse_match_ifnames);
+CONFIG_PARSER_PROTOTYPE(config_parse_match_property);
+CONFIG_PARSER_PROTOTYPE(config_parse_ifalias);
+CONFIG_PARSER_PROTOTYPE(config_parse_bridge_port_priority);
+
+int net_get_unique_predictable_data(sd_device *device, bool use_sysname, uint64_t *result);
+const char *net_get_name_persistent(sd_device *device);
+
+size_t serialize_in_addrs(FILE *f,
+                          const struct in_addr *addresses,
+                          size_t size,
+                          bool *with_leading_space,
+                          bool (*predicate)(const struct in_addr *addr));
+int deserialize_in_addrs(struct in_addr **addresses, const char *string);
+void serialize_in6_addrs(FILE *f, const struct in6_addr *addresses,
+                         size_t size,
+                         bool *with_leading_space);
+int deserialize_in6_addrs(struct in6_addr **addresses, const char *string);
+
+/* don't include "dhcp-lease-internal.h" as it causes conflicts between netinet/ip.h and linux/ip.h */
+struct sd_dhcp_route;
+struct sd_dhcp_lease;
+
+void serialize_dhcp_routes(FILE *f, const char *key, sd_dhcp_route **routes, size_t size);
+int deserialize_dhcp_routes(struct sd_dhcp_route **ret, size_t *ret_size, size_t *ret_allocated, const char *string);
+
+/* It is not necessary to add deserialize_dhcp_option(). Use unhexmem() instead. */
+int serialize_dhcp_option(FILE *f, const char *key, const void *data, size_t size);
+
+int dhcp_lease_save(sd_dhcp_lease *lease, const char *lease_file);
+int dhcp_lease_load(sd_dhcp_lease **ret, const char *lease_file);
diff --git a/src/libsystemd-network/radv-internal.h b/src/libsystemd-network/radv-internal.h
new file mode 100644
index 0000000..3dbeffe
--- /dev/null
+++ b/src/libsystemd-network/radv-internal.h
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/***
+  Copyright © 2017 Intel Corporation. All rights reserved.
+***/
+
+#include "sd-radv.h"
+
+#include "log.h"
+#include "list.h"
+#include "sparse-endian.h"
+
+assert_cc(SD_RADV_DEFAULT_MIN_TIMEOUT_USEC <= SD_RADV_DEFAULT_MAX_TIMEOUT_USEC);
+
+#define SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC (16*USEC_PER_SEC)
+#define SD_RADV_MAX_INITIAL_RTR_ADVERTISEMENTS  3
+#define SD_RADV_MAX_FINAL_RTR_ADVERTISEMENTS    3
+#define SD_RADV_MIN_DELAY_BETWEEN_RAS           3
+#define SD_RADV_MAX_RA_DELAY_TIME_USEC          (500*USEC_PER_MSEC)
+
+#define SD_RADV_OPT_ROUTE_INFORMATION           24
+#define SD_RADV_OPT_RDNSS                       25
+#define SD_RADV_OPT_DNSSL                       31
+
+enum RAdvState {
+        SD_RADV_STATE_IDLE                      = 0,
+        SD_RADV_STATE_ADVERTISING               = 1,
+};
+typedef enum RAdvState RAdvState;
+
+struct sd_radv_opt_dns {
+        uint8_t type;
+        uint8_t length;
+        uint16_t reserved;
+        be32_t lifetime;
+} _packed_;
+
+struct sd_radv {
+        unsigned n_ref;
+        RAdvState state;
+
+        int ifindex;
+
+        sd_event *event;
+        int event_priority;
+
+        struct ether_addr mac_addr;
+        uint8_t hop_limit;
+        uint8_t flags;
+        uint32_t mtu;
+        uint16_t lifetime;
+
+        int fd;
+        unsigned ra_sent;
+        sd_event_source *recv_event_source;
+        sd_event_source *timeout_event_source;
+
+        unsigned n_prefixes;
+        LIST_HEAD(sd_radv_prefix, prefixes);
+
+        unsigned n_route_prefixes;
+        LIST_HEAD(sd_radv_route_prefix, route_prefixes);
+
+        size_t n_rdnss;
+        struct sd_radv_opt_dns *rdnss;
+        struct sd_radv_opt_dns *dnssl;
+};
+
+#define radv_prefix_opt__contents {             \
+        uint8_t type;                           \
+        uint8_t length;                         \
+        uint8_t prefixlen;                      \
+        uint8_t flags;                          \
+        be32_t valid_lifetime;                  \
+        be32_t preferred_lifetime;              \
+        uint32_t reserved;                      \
+        struct in6_addr in6_addr;               \
+}
+
+struct radv_prefix_opt radv_prefix_opt__contents;
+
+/* We need the opt substructure to be packed, because we use it in send(). But
+ * if we use _packed_, this means that the structure cannot be used directly in
+ * normal code in general, because the fields might not be properly aligned.
+ * But in this particular case, the structure is defined in a way that gives
+ * proper alignment, even without the explicit _packed_ attribute. To appease
+ * the compiler we use the "unpacked" structure, but we also verify that
+ * structure contains no holes, so offsets are the same when _packed_ is used.
+ */
+struct radv_prefix_opt__packed radv_prefix_opt__contents _packed_;
+assert_cc(sizeof(struct radv_prefix_opt) == sizeof(struct radv_prefix_opt__packed));
+
+struct sd_radv_prefix {
+        unsigned n_ref;
+
+        struct radv_prefix_opt opt;
+
+        LIST_FIELDS(struct sd_radv_prefix, prefix);
+
+        usec_t valid_until;
+        usec_t preferred_until;
+};
+
+#define radv_route_prefix_opt__contents {       \
+        uint8_t type;                           \
+        uint8_t length;                         \
+        uint8_t prefixlen;                      \
+        uint8_t flags_reserved;                 \
+        be32_t  lifetime;                       \
+        struct in6_addr in6_addr;               \
+}
+
+struct radv_route_prefix_opt radv_route_prefix_opt__contents;
+
+struct radv_route_prefix_opt__packed radv_route_prefix_opt__contents _packed_;
+assert_cc(sizeof(struct radv_route_prefix_opt) == sizeof(struct radv_route_prefix_opt__packed));
+
+struct sd_radv_route_prefix {
+        unsigned n_ref;
+
+        struct radv_route_prefix_opt opt;
+
+        LIST_FIELDS(struct sd_radv_route_prefix, prefix);
+};
+
+#define log_radv_full(level, error, fmt, ...) log_internal(level, error, PROJECT_FILE, __LINE__, __func__, "RADV: " fmt, ##__VA_ARGS__)
+#define log_radv_errno(error, fmt, ...) log_radv_full(LOG_DEBUG, error, fmt, ##__VA_ARGS__)
+#define log_radv(fmt, ...) log_radv_errno(0, fmt, ##__VA_ARGS__)
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
new file mode 100644
index 0000000..d472fcd
--- /dev/null
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -0,0 +1,2267 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <net/ethernet.h>
+#include <net/if_arp.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <linux/if_infiniband.h>
+
+#include "sd-dhcp-client.h"
+
+#include "alloc-util.h"
+#include "dhcp-identifier.h"
+#include "dhcp-internal.h"
+#include "dhcp-lease-internal.h"
+#include "dhcp-protocol.h"
+#include "dns-domain.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "hostname-util.h"
+#include "io-util.h"
+#include "memory-util.h"
+#include "random-util.h"
+#include "set.h"
+#include "sort-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "utf8.h"
+#include "web-util.h"
+
+#define MAX_CLIENT_ID_LEN (sizeof(uint32_t) + MAX_DUID_LEN)  /* Arbitrary limit */
+#define MAX_MAC_ADDR_LEN CONST_MAX(INFINIBAND_ALEN, ETH_ALEN)
+
+#define RESTART_AFTER_NAK_MIN_USEC (1 * USEC_PER_SEC)
+#define RESTART_AFTER_NAK_MAX_USEC (30 * USEC_PER_MINUTE)
+
+typedef struct sd_dhcp_client_id {
+        uint8_t type;
+        union {
+                struct {
+                        /* 0: Generic (non-LL) (RFC 2132) */
+                        uint8_t data[MAX_CLIENT_ID_LEN];
+                } _packed_ gen;
+                struct {
+                        /* 1: Ethernet Link-Layer (RFC 2132) */
+                        uint8_t haddr[ETH_ALEN];
+                } _packed_ eth;
+                struct {
+                        /* 2 - 254: ARP/Link-Layer (RFC 2132) */
+                        uint8_t haddr[0];
+                } _packed_ ll;
+                struct {
+                        /* 255: Node-specific (RFC 4361) */
+                        be32_t iaid;
+                        struct duid duid;
+                } _packed_ ns;
+                struct {
+                        uint8_t data[MAX_CLIENT_ID_LEN];
+                } _packed_ raw;
+        };
+} _packed_ sd_dhcp_client_id;
+
+struct sd_dhcp_client {
+        unsigned n_ref;
+
+        DHCPState state;
+        sd_event *event;
+        int event_priority;
+        sd_event_source *timeout_resend;
+        int ifindex;
+        int fd;
+        uint16_t port;
+        union sockaddr_union link;
+        sd_event_source *receive_message;
+        bool request_broadcast;
+        Set *req_opts;
+        bool anonymize;
+        be32_t last_addr;
+        uint8_t mac_addr[MAX_MAC_ADDR_LEN];
+        size_t mac_addr_len;
+        uint8_t bcast_addr[MAX_MAC_ADDR_LEN];
+        size_t bcast_addr_len;
+        uint16_t arp_type;
+        sd_dhcp_client_id client_id;
+        size_t client_id_len;
+        char *hostname;
+        char *vendor_class_identifier;
+        char *mudurl;
+        char **user_class;
+        uint32_t mtu;
+        uint32_t fallback_lease_lifetime;
+        uint32_t xid;
+        usec_t start_time;
+        uint64_t attempt;
+        uint64_t max_attempts;
+        OrderedHashmap *extra_options;
+        OrderedHashmap *vendor_options;
+        usec_t request_sent;
+        sd_event_source *timeout_t1;
+        sd_event_source *timeout_t2;
+        sd_event_source *timeout_expire;
+        sd_dhcp_client_callback_t callback;
+        void *userdata;
+        sd_dhcp_lease *lease;
+        usec_t start_delay;
+        int ip_service_type;
+};
+
+static const uint8_t default_req_opts[] = {
+        SD_DHCP_OPTION_SUBNET_MASK,
+        SD_DHCP_OPTION_ROUTER,
+        SD_DHCP_OPTION_HOST_NAME,
+        SD_DHCP_OPTION_DOMAIN_NAME,
+        SD_DHCP_OPTION_DOMAIN_NAME_SERVER,
+};
+
+/* RFC7844 section 3:
+   MAY contain the Parameter Request List option.
+   RFC7844 section 3.6:
+   The client intending to protect its privacy SHOULD only request a
+   minimal number of options in the PRL and SHOULD also randomly shuffle
+   the ordering of option codes in the PRL.  If this random ordering
+   cannot be implemented, the client MAY order the option codes in the
+   PRL by option code number (lowest to highest).
+*/
+/* NOTE: using PRL options that Windows 10 RFC7844 implementation uses */
+static const uint8_t default_req_opts_anonymize[] = {
+        SD_DHCP_OPTION_SUBNET_MASK,                     /* 1 */
+        SD_DHCP_OPTION_ROUTER,                          /* 3 */
+        SD_DHCP_OPTION_DOMAIN_NAME_SERVER,              /* 6 */
+        SD_DHCP_OPTION_DOMAIN_NAME,                     /* 15 */
+        SD_DHCP_OPTION_ROUTER_DISCOVER,                 /* 31 */
+        SD_DHCP_OPTION_STATIC_ROUTE,                    /* 33 */
+        SD_DHCP_OPTION_VENDOR_SPECIFIC,                 /* 43 */
+        SD_DHCP_OPTION_NETBIOS_NAMESERVER,              /* 44 */
+        SD_DHCP_OPTION_NETBIOS_NODETYPE,                /* 46 */
+        SD_DHCP_OPTION_NETBIOS_SCOPE,                   /* 47 */
+        SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE,          /* 121 */
+        SD_DHCP_OPTION_PRIVATE_CLASSLESS_STATIC_ROUTE,  /* 249 */
+        SD_DHCP_OPTION_PRIVATE_PROXY_AUTODISCOVERY,     /* 252 */
+};
+
+static int client_receive_message_raw(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata);
+static int client_receive_message_udp(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata);
+static void client_stop(sd_dhcp_client *client, int error);
+
+int sd_dhcp_client_id_to_string(const void *data, size_t len, char **ret) {
+        const sd_dhcp_client_id *client_id = data;
+        _cleanup_free_ char *t = NULL;
+        int r = 0;
+
+        assert_return(data, -EINVAL);
+        assert_return(len >= 1, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        len -= 1;
+        if (len > MAX_CLIENT_ID_LEN)
+                return -EINVAL;
+
+        switch (client_id->type) {
+        case 0:
+                if (utf8_is_printable((char *) client_id->gen.data, len))
+                        r = asprintf(&t, "%.*s", (int) len, client_id->gen.data);
+                else
+                        r = asprintf(&t, "DATA");
+                break;
+        case 1:
+                if (len != sizeof_field(sd_dhcp_client_id, eth))
+                        return -EINVAL;
+
+                r = asprintf(&t, "%x:%x:%x:%x:%x:%x",
+                             client_id->eth.haddr[0],
+                             client_id->eth.haddr[1],
+                             client_id->eth.haddr[2],
+                             client_id->eth.haddr[3],
+                             client_id->eth.haddr[4],
+                             client_id->eth.haddr[5]);
+                break;
+        case 2 ... 254:
+                r = asprintf(&t, "ARP/LL");
+                break;
+        case 255:
+                if (len < 6)
+                        return -EINVAL;
+
+                uint32_t iaid = be32toh(client_id->ns.iaid);
+                uint16_t duid_type = be16toh(client_id->ns.duid.type);
+                if (dhcp_validate_duid_len(duid_type, len - 6, true) < 0)
+                        return -EINVAL;
+
+                r = asprintf(&t, "IAID:0x%x/DUID", iaid);
+                break;
+        }
+
+        if (r < 0)
+                return -ENOMEM;
+        *ret = TAKE_PTR(t);
+        return 0;
+}
+
+int sd_dhcp_client_set_callback(
+                sd_dhcp_client *client,
+                sd_dhcp_client_callback_t cb,
+                void *userdata) {
+
+        assert_return(client, -EINVAL);
+
+        client->callback = cb;
+        client->userdata = userdata;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_request_broadcast(sd_dhcp_client *client, int broadcast) {
+        assert_return(client, -EINVAL);
+
+        client->request_broadcast = !!broadcast;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
+        assert_return(client, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY);
+
+        switch(option) {
+
+        case SD_DHCP_OPTION_PAD:
+        case SD_DHCP_OPTION_OVERLOAD:
+        case SD_DHCP_OPTION_MESSAGE_TYPE:
+        case SD_DHCP_OPTION_PARAMETER_REQUEST_LIST:
+        case SD_DHCP_OPTION_END:
+                return -EINVAL;
+
+        default:
+                break;
+        }
+
+        return set_ensure_put(&client->req_opts, NULL, UINT8_TO_PTR(option));
+}
+
+int sd_dhcp_client_set_request_address(
+                sd_dhcp_client *client,
+                const struct in_addr *last_addr) {
+
+        assert_return(client, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY);
+
+        if (last_addr)
+                client->last_addr = last_addr->s_addr;
+        else
+                client->last_addr = INADDR_ANY;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_ifindex(sd_dhcp_client *client, int ifindex) {
+
+        assert_return(client, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED), -EBUSY);
+        assert_return(ifindex > 0, -EINVAL);
+
+        client->ifindex = ifindex;
+        return 0;
+}
+
+int sd_dhcp_client_set_mac(
+                sd_dhcp_client *client,
+                const uint8_t *addr,
+                const uint8_t *bcast_addr,
+                size_t addr_len,
+                uint16_t arp_type) {
+
+        DHCP_CLIENT_DONT_DESTROY(client);
+        bool need_restart = false;
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(addr, -EINVAL);
+        assert_return(addr_len > 0 && addr_len <= MAX_MAC_ADDR_LEN, -EINVAL);
+        assert_return(arp_type > 0, -EINVAL);
+
+        if (arp_type == ARPHRD_ETHER)
+                assert_return(addr_len == ETH_ALEN, -EINVAL);
+        else if (arp_type == ARPHRD_INFINIBAND)
+                assert_return(addr_len == INFINIBAND_ALEN, -EINVAL);
+        else
+                return -EINVAL;
+
+        if (client->mac_addr_len == addr_len &&
+            memcmp(&client->mac_addr, addr, addr_len) == 0 &&
+            (client->bcast_addr_len > 0) == !!bcast_addr &&
+            (!bcast_addr || memcmp(&client->bcast_addr, bcast_addr, addr_len) == 0))
+                return 0;
+
+        if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) {
+                log_dhcp_client(client, "Changing MAC address on running DHCP client, restarting");
+                need_restart = true;
+                client_stop(client, SD_DHCP_CLIENT_EVENT_STOP);
+        }
+
+        memcpy(&client->mac_addr, addr, addr_len);
+        client->mac_addr_len = addr_len;
+        client->arp_type = arp_type;
+        client->bcast_addr_len = 0;
+
+        if (bcast_addr) {
+                memcpy(&client->bcast_addr, bcast_addr, addr_len);
+                client->bcast_addr_len = addr_len;
+        }
+
+        if (need_restart && client->state != DHCP_STATE_STOPPED) {
+                r = sd_dhcp_client_start(client);
+                if (r < 0)
+                        return log_dhcp_client_errno(client, r, "Failed to restart DHCPv4 client: %m");
+        }
+
+        return 0;
+}
+
+int sd_dhcp_client_get_client_id(
+                sd_dhcp_client *client,
+                uint8_t *type,
+                const uint8_t **data,
+                size_t *data_len) {
+
+        assert_return(client, -EINVAL);
+        assert_return(type, -EINVAL);
+        assert_return(data, -EINVAL);
+        assert_return(data_len, -EINVAL);
+
+        *type = 0;
+        *data = NULL;
+        *data_len = 0;
+        if (client->client_id_len) {
+                *type = client->client_id.type;
+                *data = client->client_id.raw.data;
+                *data_len = client->client_id_len - sizeof(client->client_id.type);
+        }
+
+        return 0;
+}
+
+int sd_dhcp_client_set_client_id(
+                sd_dhcp_client *client,
+                uint8_t type,
+                const uint8_t *data,
+                size_t data_len) {
+
+        DHCP_CLIENT_DONT_DESTROY(client);
+        bool need_restart = false;
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(data, -EINVAL);
+        assert_return(data_len > 0 && data_len <= MAX_CLIENT_ID_LEN, -EINVAL);
+
+        if (client->client_id_len == data_len + sizeof(client->client_id.type) &&
+            client->client_id.type == type &&
+            memcmp(&client->client_id.raw.data, data, data_len) == 0)
+                return 0;
+
+        /* For hardware types, log debug message about unexpected data length.
+         *
+         * Note that infiniband's INFINIBAND_ALEN is 20 bytes long, but only
+         * the last 8 bytes of the address are stable and suitable to put into
+         * the client-id. The caller is advised to account for that. */
+        if ((type == ARPHRD_ETHER && data_len != ETH_ALEN) ||
+            (type == ARPHRD_INFINIBAND && data_len != 8))
+                log_dhcp_client(client, "Changing client ID to hardware type %u with "
+                                "unexpected address length %zu",
+                                type, data_len);
+
+        if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) {
+                log_dhcp_client(client, "Changing client ID on running DHCP "
+                                "client, restarting");
+                need_restart = true;
+                client_stop(client, SD_DHCP_CLIENT_EVENT_STOP);
+        }
+
+        client->client_id.type = type;
+        memcpy(&client->client_id.raw.data, data, data_len);
+        client->client_id_len = data_len + sizeof (client->client_id.type);
+
+        if (need_restart && client->state != DHCP_STATE_STOPPED) {
+                r = sd_dhcp_client_start(client);
+                if (r < 0)
+                        return log_dhcp_client_errno(client, r, "Failed to restart DHCPv4 client: %m");
+        }
+
+        return 0;
+}
+
+/**
+ * Sets IAID and DUID. If duid is non-null, the DUID is set to duid_type + duid
+ * without further modification. Otherwise, if duid_type is supported, DUID
+ * is set based on that type. Otherwise, an error is returned.
+ */
+static int dhcp_client_set_iaid_duid_internal(
+                sd_dhcp_client *client,
+                bool iaid_append,
+                bool iaid_set,
+                uint32_t iaid,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len,
+                usec_t llt_time) {
+
+        DHCP_CLIENT_DONT_DESTROY(client);
+        int r;
+        size_t len;
+
+        assert_return(client, -EINVAL);
+        assert_return(duid_len == 0 || duid, -EINVAL);
+
+        if (duid) {
+                r = dhcp_validate_duid_len(duid_type, duid_len, true);
+                if (r < 0)
+                        return log_dhcp_client_errno(client, r, "Failed to validate length of DUID: %m");
+        }
+
+        zero(client->client_id);
+        client->client_id.type = 255;
+
+        if (iaid_append) {
+                if (iaid_set)
+                        client->client_id.ns.iaid = htobe32(iaid);
+                else {
+                        r = dhcp_identifier_set_iaid(client->ifindex, client->mac_addr,
+                                                     client->mac_addr_len,
+                                                     true,
+                                                     &client->client_id.ns.iaid);
+                        if (r < 0)
+                                return log_dhcp_client_errno(client, r, "Failed to set IAID: %m");
+                }
+        }
+
+        if (duid) {
+                client->client_id.ns.duid.type = htobe16(duid_type);
+                memcpy(&client->client_id.ns.duid.raw.data, duid, duid_len);
+                len = sizeof(client->client_id.ns.duid.type) + duid_len;
+        } else
+                switch (duid_type) {
+                case DUID_TYPE_LLT:
+                        if (client->mac_addr_len == 0)
+                                return log_dhcp_client_errno(client, SYNTHETIC_ERRNO(EOPNOTSUPP), "Failed to set DUID-LLT, MAC address is not set.");
+
+                        r = dhcp_identifier_set_duid_llt(&client->client_id.ns.duid, llt_time, client->mac_addr, client->mac_addr_len, client->arp_type, &len);
+                        if (r < 0)
+                                return log_dhcp_client_errno(client, r, "Failed to set DUID-LLT: %m");
+                        break;
+                case DUID_TYPE_EN:
+                        r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid, &len);
+                        if (r < 0)
+                                return log_dhcp_client_errno(client, r, "Failed to set DUID-EN: %m");
+                        break;
+                case DUID_TYPE_LL:
+                        if (client->mac_addr_len == 0)
+                                return log_dhcp_client_errno(client, SYNTHETIC_ERRNO(EOPNOTSUPP), "Failed to set DUID-LL, MAC address is not set.");
+
+                        r = dhcp_identifier_set_duid_ll(&client->client_id.ns.duid, client->mac_addr, client->mac_addr_len, client->arp_type, &len);
+                        if (r < 0)
+                                return log_dhcp_client_errno(client, r, "Failed to set DUID-LL: %m");
+                        break;
+                case DUID_TYPE_UUID:
+                        r = dhcp_identifier_set_duid_uuid(&client->client_id.ns.duid, &len);
+                        if (r < 0)
+                                return log_dhcp_client_errno(client, r, "Failed to set DUID-UUID: %m");
+                        break;
+                default:
+                        return log_dhcp_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "Invalid DUID type");
+                }
+
+        client->client_id_len = sizeof(client->client_id.type) + len +
+                                (iaid_append ? sizeof(client->client_id.ns.iaid) : 0);
+
+        if (!IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_STOPPED)) {
+                log_dhcp_client(client, "Configured %sDUID, restarting.", iaid_append ? "IAID+" : "");
+                client_stop(client, SD_DHCP_CLIENT_EVENT_STOP);
+                r = sd_dhcp_client_start(client);
+                if (r < 0)
+                        return log_dhcp_client_errno(client, r, "Failed to restart DHCPv4 client: %m");
+        }
+
+        return 0;
+}
+
+int sd_dhcp_client_set_iaid_duid(
+                sd_dhcp_client *client,
+                bool iaid_set,
+                uint32_t iaid,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len) {
+        return dhcp_client_set_iaid_duid_internal(client, true, iaid_set, iaid, duid_type, duid, duid_len, 0);
+}
+
+int sd_dhcp_client_set_iaid_duid_llt(
+                sd_dhcp_client *client,
+                bool iaid_set,
+                uint32_t iaid,
+                usec_t llt_time) {
+        return dhcp_client_set_iaid_duid_internal(client, true, iaid_set, iaid, DUID_TYPE_LLT, NULL, 0, llt_time);
+}
+
+int sd_dhcp_client_set_duid(
+                sd_dhcp_client *client,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len) {
+        return dhcp_client_set_iaid_duid_internal(client, false, false, 0, duid_type, duid, duid_len, 0);
+}
+
+int sd_dhcp_client_set_duid_llt(
+                sd_dhcp_client *client,
+                usec_t llt_time) {
+        return dhcp_client_set_iaid_duid_internal(client, false, false, 0, DUID_TYPE_LLT, NULL, 0, llt_time);
+}
+
+int sd_dhcp_client_set_hostname(
+                sd_dhcp_client *client,
+                const char *hostname) {
+
+        assert_return(client, -EINVAL);
+
+        /* Make sure hostnames qualify as DNS and as Linux hostnames */
+        if (hostname &&
+            !(hostname_is_valid(hostname, false) && dns_name_is_valid(hostname) > 0))
+                return -EINVAL;
+
+        return free_and_strdup(&client->hostname, hostname);
+}
+
+int sd_dhcp_client_set_vendor_class_identifier(
+                sd_dhcp_client *client,
+                const char *vci) {
+
+        assert_return(client, -EINVAL);
+
+        return free_and_strdup(&client->vendor_class_identifier, vci);
+}
+
+int sd_dhcp_client_set_mud_url(
+                sd_dhcp_client *client,
+                const char *mudurl) {
+
+        assert_return(client, -EINVAL);
+        assert_return(mudurl, -EINVAL);
+        assert_return(strlen(mudurl) <= 255, -EINVAL);
+        assert_return(http_url_is_valid(mudurl), -EINVAL);
+
+        return free_and_strdup(&client->mudurl, mudurl);
+}
+
+int sd_dhcp_client_set_user_class(
+                sd_dhcp_client *client,
+                char * const *user_class) {
+
+        char * const *p;
+        char **s = NULL;
+
+        assert_return(client, -EINVAL);
+        assert_return(!strv_isempty(user_class), -EINVAL);
+
+        STRV_FOREACH(p, user_class) {
+                size_t n = strlen(*p);
+
+                if (n > 255 || n == 0)
+                        return -EINVAL;
+        }
+
+        s = strv_copy(user_class);
+        if (!s)
+                return -ENOMEM;
+
+        return strv_free_and_replace(client->user_class, s);
+}
+
+int sd_dhcp_client_set_client_port(
+                sd_dhcp_client *client,
+                uint16_t port) {
+
+        assert_return(client, -EINVAL);
+
+        client->port = port;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_mtu(sd_dhcp_client *client, uint32_t mtu) {
+        assert_return(client, -EINVAL);
+        assert_return(mtu >= DHCP_DEFAULT_MIN_SIZE, -ERANGE);
+
+        client->mtu = mtu;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_max_attempts(sd_dhcp_client *client, uint64_t max_attempts) {
+        assert_return(client, -EINVAL);
+
+        client->max_attempts = max_attempts;
+
+        return 0;
+}
+
+int sd_dhcp_client_add_option(sd_dhcp_client *client, sd_dhcp_option *v) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(v, -EINVAL);
+
+        r = ordered_hashmap_ensure_allocated(&client->extra_options, &dhcp_option_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = ordered_hashmap_put(client->extra_options, UINT_TO_PTR(v->option), v);
+        if (r < 0)
+                return r;
+
+        sd_dhcp_option_ref(v);
+        return 0;
+}
+
+int sd_dhcp_client_add_vendor_option(sd_dhcp_client *client, sd_dhcp_option *v) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(v, -EINVAL);
+
+        r = ordered_hashmap_ensure_allocated(&client->vendor_options, &dhcp_option_hash_ops);
+        if (r < 0)
+                return -ENOMEM;
+
+        r = ordered_hashmap_put(client->vendor_options, v, v);
+        if (r < 0)
+                return r;
+
+        sd_dhcp_option_ref(v);
+
+        return 1;
+}
+
+int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
+        assert_return(client, -EINVAL);
+
+        if (!IN_SET(client->state, DHCP_STATE_SELECTING, DHCP_STATE_BOUND, DHCP_STATE_RENEWING, DHCP_STATE_REBINDING))
+                return -EADDRNOTAVAIL;
+
+        if (ret)
+                *ret = client->lease;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_service_type(sd_dhcp_client *client, int type) {
+        assert_return(client, -EINVAL);
+
+        client->ip_service_type = type;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_fallback_lease_lifetime(sd_dhcp_client *client, uint32_t fallback_lease_lifetime) {
+        assert_return(client, -EINVAL);
+        assert_return(fallback_lease_lifetime > 0, -EINVAL);
+
+        client->fallback_lease_lifetime = fallback_lease_lifetime;
+
+        return 0;
+}
+
+static int client_notify(sd_dhcp_client *client, int event) {
+        assert(client);
+
+        if (client->callback)
+                return client->callback(client, event, client->userdata);
+
+        return 0;
+}
+
+static int client_initialize(sd_dhcp_client *client) {
+        assert_return(client, -EINVAL);
+
+        client->receive_message = sd_event_source_unref(client->receive_message);
+
+        client->fd = safe_close(client->fd);
+
+        (void) event_source_disable(client->timeout_resend);
+        (void) event_source_disable(client->timeout_t1);
+        (void) event_source_disable(client->timeout_t2);
+        (void) event_source_disable(client->timeout_expire);
+
+        client->attempt = 0;
+
+        client->state = DHCP_STATE_INIT;
+        client->xid = 0;
+
+        client->lease = sd_dhcp_lease_unref(client->lease);
+
+        return 0;
+}
+
+static void client_stop(sd_dhcp_client *client, int error) {
+        assert(client);
+
+        if (error < 0)
+                log_dhcp_client_errno(client, error, "STOPPED: %m");
+        else if (error == SD_DHCP_CLIENT_EVENT_STOP)
+                log_dhcp_client(client, "STOPPED");
+        else
+                log_dhcp_client(client, "STOPPED: Unknown event");
+
+        client_notify(client, error);
+
+        client_initialize(client);
+}
+
+static int cmp_uint8(const uint8_t *a, const uint8_t *b) {
+        return CMP(*a, *b);
+}
+
+static int client_message_init(
+                sd_dhcp_client *client,
+                DHCPPacket **ret,
+                uint8_t type,
+                size_t *_optlen,
+                size_t *_optoffset) {
+
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        size_t optlen, optoffset, size;
+        be16_t max_size;
+        usec_t time_now;
+        uint16_t secs;
+        int r;
+
+        assert(client);
+        assert(client->start_time);
+        assert(ret);
+        assert(_optlen);
+        assert(_optoffset);
+        assert(IN_SET(type, DHCP_DISCOVER, DHCP_REQUEST, DHCP_RELEASE, DHCP_DECLINE));
+
+        optlen = DHCP_MIN_OPTIONS_SIZE;
+        size = sizeof(DHCPPacket) + optlen;
+
+        packet = malloc0(size);
+        if (!packet)
+                return -ENOMEM;
+
+        r = dhcp_message_init(&packet->dhcp, BOOTREQUEST, client->xid, type,
+                              client->arp_type, optlen, &optoffset);
+        if (r < 0)
+                return r;
+
+        /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
+           refuse to issue an DHCP lease if 'secs' is set to zero */
+        r = sd_event_now(client->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                return r;
+        assert(time_now >= client->start_time);
+
+        /* seconds between sending first and last DISCOVER
+         * must always be strictly positive to deal with broken servers */
+        secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
+        packet->dhcp.secs = htobe16(secs);
+
+        /* RFC2132 section 4.1
+           A client that cannot receive unicast IP datagrams until its protocol
+           software has been configured with an IP address SHOULD set the
+           BROADCAST bit in the 'flags' field to 1 in any DHCPDISCOVER or
+           DHCPREQUEST messages that client sends.  The BROADCAST bit will
+           provide a hint to the DHCP server and BOOTP relay agent to broadcast
+           any messages to the client on the client's subnet.
+
+           Note: some interfaces needs this to be enabled, but some networks
+           needs this to be disabled as broadcasts are filteretd, so this
+           needs to be configurable */
+        if (client->request_broadcast || client->arp_type != ARPHRD_ETHER)
+                packet->dhcp.flags = htobe16(0x8000);
+
+        /* RFC2132 section 4.1.1:
+           The client MUST include its hardware address in the ’chaddr’ field, if
+           necessary for delivery of DHCP reply messages.  Non-Ethernet
+           interfaces will leave 'chaddr' empty and use the client identifier
+           instead (eg, RFC 4390 section 2.1).
+         */
+        if (client->arp_type == ARPHRD_ETHER)
+                memcpy(&packet->dhcp.chaddr, &client->mac_addr, ETH_ALEN);
+
+        /* If no client identifier exists, construct an RFC 4361-compliant one */
+        if (client->client_id_len == 0) {
+                size_t duid_len;
+
+                client->client_id.type = 255;
+
+                r = dhcp_identifier_set_iaid(client->ifindex, client->mac_addr, client->mac_addr_len,
+                                             true, &client->client_id.ns.iaid);
+                if (r < 0)
+                        return r;
+
+                r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid, &duid_len);
+                if (r < 0)
+                        return r;
+
+                client->client_id_len = sizeof(client->client_id.type) + sizeof(client->client_id.ns.iaid) + duid_len;
+        }
+
+        /* Some DHCP servers will refuse to issue an DHCP lease if the Client
+           Identifier option is not set */
+        if (client->client_id_len) {
+                r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0,
+                                       SD_DHCP_OPTION_CLIENT_IDENTIFIER,
+                                       client->client_id_len,
+                                       &client->client_id);
+                if (r < 0)
+                        return r;
+        }
+
+        /* RFC2131 section 3.5:
+           in its initial DHCPDISCOVER or DHCPREQUEST message, a
+           client may provide the server with a list of specific
+           parameters the client is interested in. If the client
+           includes a list of parameters in a DHCPDISCOVER message,
+           it MUST include that list in any subsequent DHCPREQUEST
+           messages.
+         */
+
+        /* RFC7844 section 3:
+           MAY contain the Parameter Request List option. */
+        /* NOTE: in case that there would be an option to do not send
+         * any PRL at all, the size should be checked before sending */
+        if (!set_isempty(client->req_opts) && type != DHCP_RELEASE) {
+                _cleanup_free_ uint8_t *opts = NULL;
+                size_t n_opts, i = 0;
+                void *val;
+
+                n_opts = set_size(client->req_opts);
+                opts = new(uint8_t, n_opts);
+                if (!opts)
+                        return -ENOMEM;
+
+                SET_FOREACH(val, client->req_opts)
+                        opts[i++] = PTR_TO_UINT8(val);
+                assert(i == n_opts);
+
+                /* For anonymizing the request, let's sort the options. */
+                typesafe_qsort(opts, n_opts, cmp_uint8);
+
+                r = dhcp_option_append(&packet->dhcp, optlen, &optoffset, 0,
+                                       SD_DHCP_OPTION_PARAMETER_REQUEST_LIST,
+                                       n_opts, opts);
+                if (r < 0)
+                        return r;
+        }
+
+        /* RFC2131 section 3.5:
+           The client SHOULD include the ’maximum DHCP message size’ option to
+           let the server know how large the server may make its DHCP messages.
+
+           Note (from ConnMan): Some DHCP servers will send bigger DHCP packets
+           than the defined default size unless the Maximum Message Size option
+           is explicitly set
+
+           RFC3442 "Requirements to Avoid Sizing Constraints":
+           Because a full routing table can be quite large, the standard 576
+           octet maximum size for a DHCP message may be too short to contain
+           some legitimate Classless Static Route options.  Because of this,
+           clients implementing the Classless Static Route option SHOULD send a
+           Maximum DHCP Message Size [4] option if the DHCP client's TCP/IP
+           stack is capable of receiving larger IP datagrams.  In this case, the
+           client SHOULD set the value of this option to at least the MTU of the
+           interface that the client is configuring.  The client MAY set the
+           value of this option higher, up to the size of the largest UDP packet
+           it is prepared to accept.  (Note that the value specified in the
+           Maximum DHCP Message Size option is the total maximum packet size,
+           including IP and UDP headers.)
+         */
+        /* RFC7844 section 3:
+           SHOULD NOT contain any other option. */
+        if (!client->anonymize && type != DHCP_RELEASE) {
+                max_size = htobe16(size);
+                r = dhcp_option_append(&packet->dhcp, client->mtu, &optoffset, 0,
+                                       SD_DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
+                                       2, &max_size);
+                if (r < 0)
+                        return r;
+        }
+
+        *_optlen = optlen;
+        *_optoffset = optoffset;
+        *ret = TAKE_PTR(packet);
+
+        return 0;
+}
+
+static int client_append_fqdn_option(
+                DHCPMessage *message,
+                size_t optlen,
+                size_t *optoffset,
+                const char *fqdn) {
+
+        uint8_t buffer[3 + DHCP_MAX_FQDN_LENGTH];
+        int r;
+
+        buffer[0] = DHCP_FQDN_FLAG_S | /* Request server to perform A RR DNS updates */
+                    DHCP_FQDN_FLAG_E;  /* Canonical wire format */
+        buffer[1] = 0;                 /* RCODE1 (deprecated) */
+        buffer[2] = 0;                 /* RCODE2 (deprecated) */
+
+        r = dns_name_to_wire_format(fqdn, buffer + 3, sizeof(buffer) - 3, false);
+        if (r > 0)
+                r = dhcp_option_append(message, optlen, optoffset, 0,
+                                       SD_DHCP_OPTION_FQDN, 3 + r, buffer);
+
+        return r;
+}
+
+static int dhcp_client_send_raw(
+                sd_dhcp_client *client,
+                DHCPPacket *packet,
+                size_t len) {
+
+        dhcp_packet_append_ip_headers(packet, INADDR_ANY, client->port,
+                                      INADDR_BROADCAST, DHCP_PORT_SERVER, len, client->ip_service_type);
+
+        return dhcp_network_send_raw_socket(client->fd, &client->link,
+                                            packet, len);
+}
+
+static int client_append_common_discover_request_options(sd_dhcp_client *client, DHCPPacket *packet, size_t *optoffset, size_t optlen) {
+        sd_dhcp_option *j;
+        int r;
+
+        assert(client);
+
+        if (client->hostname) {
+                /* According to RFC 4702 "clients that send the Client FQDN option in
+                   their messages MUST NOT also send the Host Name option". Just send
+                   one of the two depending on the hostname type.
+                */
+                if (dns_name_is_single_label(client->hostname)) {
+                        /* it is unclear from RFC 2131 if client should send hostname in
+                           DHCPDISCOVER but dhclient does and so we do as well
+                        */
+                        r = dhcp_option_append(&packet->dhcp, optlen, optoffset, 0,
+                                               SD_DHCP_OPTION_HOST_NAME,
+                                               strlen(client->hostname), client->hostname);
+                } else
+                        r = client_append_fqdn_option(&packet->dhcp, optlen, optoffset,
+                                                      client->hostname);
+                if (r < 0)
+                        return r;
+        }
+
+        if (client->vendor_class_identifier) {
+                r = dhcp_option_append(&packet->dhcp, optlen, optoffset, 0,
+                                       SD_DHCP_OPTION_VENDOR_CLASS_IDENTIFIER,
+                                       strlen(client->vendor_class_identifier),
+                                       client->vendor_class_identifier);
+                if (r < 0)
+                        return r;
+        }
+
+        if (client->mudurl) {
+                r = dhcp_option_append(&packet->dhcp, optlen, optoffset, 0,
+                                       SD_DHCP_OPTION_MUD_URL,
+                                       strlen(client->mudurl),
+                                       client->mudurl);
+                if (r < 0)
+                        return r;
+        }
+
+        if (client->user_class) {
+                r = dhcp_option_append(&packet->dhcp, optlen, optoffset, 0,
+                                       SD_DHCP_OPTION_USER_CLASS,
+                                       strv_length(client->user_class),
+                                       client->user_class);
+                if (r < 0)
+                        return r;
+        }
+
+        ORDERED_HASHMAP_FOREACH(j, client->extra_options) {
+                r = dhcp_option_append(&packet->dhcp, optlen, optoffset, 0,
+                                       j->option, j->length, j->data);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!ordered_hashmap_isempty(client->vendor_options)) {
+                r = dhcp_option_append(
+                                &packet->dhcp, optlen, optoffset, 0,
+                                SD_DHCP_OPTION_VENDOR_SPECIFIC,
+                                ordered_hashmap_size(client->vendor_options), client->vendor_options);
+                if (r < 0)
+                        return r;
+        }
+
+
+        return 0;
+}
+
+static int client_send_discover(sd_dhcp_client *client) {
+        _cleanup_free_ DHCPPacket *discover = NULL;
+        size_t optoffset, optlen;
+        int r;
+
+        assert(client);
+        assert(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_SELECTING));
+
+        r = client_message_init(client, &discover, DHCP_DISCOVER,
+                                &optlen, &optoffset);
+        if (r < 0)
+                return r;
+
+        /* the client may suggest values for the network address
+           and lease time in the DHCPDISCOVER message. The client may include
+           the ’requested IP address’ option to suggest that a particular IP
+           address be assigned, and may include the ’IP address lease time’
+           option to suggest the lease time it would like.
+         */
+        /* RFC7844 section 3:
+           SHOULD NOT contain any other option. */
+        if (!client->anonymize && client->last_addr != INADDR_ANY) {
+                r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
+                                       SD_DHCP_OPTION_REQUESTED_IP_ADDRESS,
+                                       4, &client->last_addr);
+                if (r < 0)
+                        return r;
+        }
+
+        r = client_append_common_discover_request_options(client, discover, &optoffset, optlen);
+        if (r < 0)
+                return r;
+
+        r = dhcp_option_append(&discover->dhcp, optlen, &optoffset, 0,
+                               SD_DHCP_OPTION_END, 0, NULL);
+        if (r < 0)
+                return r;
+
+        /* We currently ignore:
+           The client SHOULD wait a random time between one and ten seconds to
+           desynchronize the use of DHCP at startup.
+         */
+        r = dhcp_client_send_raw(client, discover, sizeof(DHCPPacket) + optoffset);
+        if (r < 0)
+                return r;
+
+        log_dhcp_client(client, "DISCOVER");
+
+        return 0;
+}
+
+static int client_send_request(sd_dhcp_client *client) {
+        _cleanup_free_ DHCPPacket *request = NULL;
+        size_t optoffset, optlen;
+        int r;
+
+        assert(client);
+
+        r = client_message_init(client, &request, DHCP_REQUEST, &optlen, &optoffset);
+        if (r < 0)
+                return r;
+
+        switch (client->state) {
+        /* See RFC2131 section 4.3.2 (note that there is a typo in the RFC,
+           SELECTING should be REQUESTING)
+         */
+
+        case DHCP_STATE_REQUESTING:
+                /* Client inserts the address of the selected server in ’server
+                   identifier’, ’ciaddr’ MUST be zero, ’requested IP address’ MUST be
+                   filled in with the yiaddr value from the chosen DHCPOFFER.
+                 */
+
+                r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
+                                       SD_DHCP_OPTION_SERVER_IDENTIFIER,
+                                       4, &client->lease->server_address);
+                if (r < 0)
+                        return r;
+
+                r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
+                                       SD_DHCP_OPTION_REQUESTED_IP_ADDRESS,
+                                       4, &client->lease->address);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        case DHCP_STATE_INIT_REBOOT:
+                /* ’server identifier’ MUST NOT be filled in, ’requested IP address’
+                   option MUST be filled in with client’s notion of its previously
+                   assigned address. ’ciaddr’ MUST be zero.
+                 */
+                r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
+                                       SD_DHCP_OPTION_REQUESTED_IP_ADDRESS,
+                                       4, &client->last_addr);
+                if (r < 0)
+                        return r;
+                break;
+
+        case DHCP_STATE_RENEWING:
+                /* ’server identifier’ MUST NOT be filled in, ’requested IP address’
+                   option MUST NOT be filled in, ’ciaddr’ MUST be filled in with
+                   client’s IP address.
+                */
+
+        case DHCP_STATE_REBINDING:
+                /* ’server identifier’ MUST NOT be filled in, ’requested IP address’
+                   option MUST NOT be filled in, ’ciaddr’ MUST be filled in with
+                   client’s IP address.
+
+                   This message MUST be broadcast to the 0xffffffff IP broadcast address.
+                 */
+                request->dhcp.ciaddr = client->lease->address;
+
+                break;
+
+        case DHCP_STATE_INIT:
+        case DHCP_STATE_SELECTING:
+        case DHCP_STATE_REBOOTING:
+        case DHCP_STATE_BOUND:
+        case DHCP_STATE_STOPPED:
+                return -EINVAL;
+        }
+
+        r = client_append_common_discover_request_options(client, request, &optoffset, optlen);
+        if (r < 0)
+                return r;
+
+        r = dhcp_option_append(&request->dhcp, optlen, &optoffset, 0,
+                               SD_DHCP_OPTION_END, 0, NULL);
+        if (r < 0)
+                return r;
+
+        if (client->state == DHCP_STATE_RENEWING)
+                r = dhcp_network_send_udp_socket(client->fd,
+                                                 client->lease->server_address,
+                                                 DHCP_PORT_SERVER,
+                                                 &request->dhcp,
+                                                 sizeof(DHCPMessage) + optoffset);
+        else
+                r = dhcp_client_send_raw(client, request, sizeof(DHCPPacket) + optoffset);
+        if (r < 0)
+                return r;
+
+        switch (client->state) {
+
+        case DHCP_STATE_REQUESTING:
+                log_dhcp_client(client, "REQUEST (requesting)");
+                break;
+
+        case DHCP_STATE_INIT_REBOOT:
+                log_dhcp_client(client, "REQUEST (init-reboot)");
+                break;
+
+        case DHCP_STATE_RENEWING:
+                log_dhcp_client(client, "REQUEST (renewing)");
+                break;
+
+        case DHCP_STATE_REBINDING:
+                log_dhcp_client(client, "REQUEST (rebinding)");
+                break;
+
+        default:
+                log_dhcp_client(client, "REQUEST (invalid)");
+                break;
+        }
+
+        return 0;
+}
+
+static int client_start(sd_dhcp_client *client);
+
+static int client_timeout_resend(
+                sd_event_source *s,
+                uint64_t usec,
+                void *userdata) {
+
+        sd_dhcp_client *client = userdata;
+        DHCP_CLIENT_DONT_DESTROY(client);
+        usec_t next_timeout = 0;
+        uint64_t time_now;
+        uint32_t time_left;
+        int r;
+
+        assert(s);
+        assert(client);
+        assert(client->event);
+
+        r = sd_event_now(client->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                goto error;
+
+        switch (client->state) {
+
+        case DHCP_STATE_RENEWING:
+
+                time_left = (client->lease->t2 - client->lease->t1) / 2;
+                if (time_left < 60)
+                        time_left = 60;
+
+                next_timeout = time_now + time_left * USEC_PER_SEC;
+
+                break;
+
+        case DHCP_STATE_REBINDING:
+
+                time_left = (client->lease->lifetime - client->lease->t2) / 2;
+                if (time_left < 60)
+                        time_left = 60;
+
+                next_timeout = time_now + time_left * USEC_PER_SEC;
+                break;
+
+        case DHCP_STATE_REBOOTING:
+                /* start over as we did not receive a timely ack or nak */
+                r = client_initialize(client);
+                if (r < 0)
+                        goto error;
+
+                r = client_start(client);
+                if (r < 0)
+                        goto error;
+                else {
+                        log_dhcp_client(client, "REBOOTED");
+                        return 0;
+                }
+
+        case DHCP_STATE_INIT:
+        case DHCP_STATE_INIT_REBOOT:
+        case DHCP_STATE_SELECTING:
+        case DHCP_STATE_REQUESTING:
+        case DHCP_STATE_BOUND:
+
+                if (client->attempt < client->max_attempts)
+                        client->attempt++;
+                else
+                        goto error;
+
+                next_timeout = time_now + ((UINT64_C(1) << MIN(client->attempt, (uint64_t) 6)) - 1) * USEC_PER_SEC;
+
+                break;
+
+        case DHCP_STATE_STOPPED:
+                r = -EINVAL;
+                goto error;
+        }
+
+        next_timeout += (random_u32() & 0x1fffff);
+
+        r = event_reset_time(client->event, &client->timeout_resend,
+                             clock_boottime_or_monotonic(),
+                             next_timeout, 10 * USEC_PER_MSEC,
+                             client_timeout_resend, client,
+                             client->event_priority, "dhcp4-resend-timer", true);
+        if (r < 0)
+                goto error;
+
+        switch (client->state) {
+        case DHCP_STATE_INIT:
+                r = client_send_discover(client);
+                if (r >= 0) {
+                        client->state = DHCP_STATE_SELECTING;
+                        client->attempt = 0;
+                } else if (client->attempt >= client->max_attempts)
+                        goto error;
+
+                break;
+
+        case DHCP_STATE_SELECTING:
+                r = client_send_discover(client);
+                if (r < 0 && client->attempt >= client->max_attempts)
+                        goto error;
+
+                break;
+
+        case DHCP_STATE_INIT_REBOOT:
+        case DHCP_STATE_REQUESTING:
+        case DHCP_STATE_RENEWING:
+        case DHCP_STATE_REBINDING:
+                r = client_send_request(client);
+                if (r < 0 && client->attempt >= client->max_attempts)
+                         goto error;
+
+                if (client->state == DHCP_STATE_INIT_REBOOT)
+                        client->state = DHCP_STATE_REBOOTING;
+
+                client->request_sent = time_now;
+
+                break;
+
+        case DHCP_STATE_REBOOTING:
+        case DHCP_STATE_BOUND:
+
+                break;
+
+        case DHCP_STATE_STOPPED:
+                r = -EINVAL;
+                goto error;
+        }
+
+        return 0;
+
+error:
+        client_stop(client, r);
+
+        /* Errors were dealt with when stopping the client, don't spill
+           errors into the event loop handler */
+        return 0;
+}
+
+static int client_initialize_io_events(
+                sd_dhcp_client *client,
+                sd_event_io_handler_t io_callback) {
+
+        int r;
+
+        assert(client);
+        assert(client->event);
+
+        r = sd_event_add_io(client->event, &client->receive_message,
+                            client->fd, EPOLLIN, io_callback,
+                            client);
+        if (r < 0)
+                goto error;
+
+        r = sd_event_source_set_priority(client->receive_message,
+                                         client->event_priority);
+        if (r < 0)
+                goto error;
+
+        r = sd_event_source_set_description(client->receive_message, "dhcp4-receive-message");
+        if (r < 0)
+                goto error;
+
+error:
+        if (r < 0)
+                client_stop(client, r);
+
+        return 0;
+}
+
+static int client_initialize_time_events(sd_dhcp_client *client) {
+        uint64_t usec = 0;
+        int r;
+
+        assert(client);
+        assert(client->event);
+
+        if (client->start_delay > 0) {
+                assert_se(sd_event_now(client->event, clock_boottime_or_monotonic(), &usec) >= 0);
+                usec += client->start_delay;
+        }
+
+        r = event_reset_time(client->event, &client->timeout_resend,
+                             clock_boottime_or_monotonic(),
+                             usec, 0,
+                             client_timeout_resend, client,
+                             client->event_priority, "dhcp4-resend-timer", true);
+        if (r < 0)
+                client_stop(client, r);
+
+        return 0;
+
+}
+
+static int client_initialize_events(sd_dhcp_client *client, sd_event_io_handler_t io_callback) {
+        client_initialize_io_events(client, io_callback);
+        client_initialize_time_events(client);
+
+        return 0;
+}
+
+static int client_start_delayed(sd_dhcp_client *client) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->event, -EINVAL);
+        assert_return(client->ifindex > 0, -EINVAL);
+        assert_return(client->fd < 0, -EBUSY);
+        assert_return(client->xid == 0, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_INIT_REBOOT), -EBUSY);
+
+        client->xid = random_u32();
+
+        r = dhcp_network_bind_raw_socket(client->ifindex, &client->link, client->xid,
+                                         client->mac_addr, client->mac_addr_len,
+                                         client->bcast_addr, client->bcast_addr_len,
+                                         client->arp_type, client->port);
+        if (r < 0) {
+                client_stop(client, r);
+                return r;
+        }
+        client->fd = r;
+
+        if (IN_SET(client->state, DHCP_STATE_INIT, DHCP_STATE_INIT_REBOOT))
+                client->start_time = now(clock_boottime_or_monotonic());
+
+        return client_initialize_events(client, client_receive_message_raw);
+}
+
+static int client_start(sd_dhcp_client *client) {
+        client->start_delay = 0;
+        return client_start_delayed(client);
+}
+
+static int client_timeout_expire(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_dhcp_client *client = userdata;
+        DHCP_CLIENT_DONT_DESTROY(client);
+
+        log_dhcp_client(client, "EXPIRED");
+
+        client_notify(client, SD_DHCP_CLIENT_EVENT_EXPIRED);
+
+        /* lease was lost, start over if not freed or stopped in callback */
+        if (client->state != DHCP_STATE_STOPPED) {
+                client_initialize(client);
+                client_start(client);
+        }
+
+        return 0;
+}
+
+static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_dhcp_client *client = userdata;
+        DHCP_CLIENT_DONT_DESTROY(client);
+        int r;
+
+        assert(client);
+
+        client->receive_message = sd_event_source_unref(client->receive_message);
+        client->fd = safe_close(client->fd);
+
+        client->state = DHCP_STATE_REBINDING;
+        client->attempt = 0;
+
+        r = dhcp_network_bind_raw_socket(client->ifindex, &client->link, client->xid,
+                                         client->mac_addr, client->mac_addr_len,
+                                         client->bcast_addr, client->bcast_addr_len,
+                                         client->arp_type, client->port);
+        if (r < 0) {
+                client_stop(client, r);
+                return 0;
+        }
+        client->fd = r;
+
+        return client_initialize_events(client, client_receive_message_raw);
+}
+
+static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_dhcp_client *client = userdata;
+        DHCP_CLIENT_DONT_DESTROY(client);
+
+        if (client->lease)
+                client->state = DHCP_STATE_RENEWING;
+        else if (client->state != DHCP_STATE_INIT)
+                client->state = DHCP_STATE_INIT_REBOOT;
+        client->attempt = 0;
+
+        return client_initialize_time_events(client);
+}
+
+static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer, size_t len) {
+        _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL;
+        int r;
+
+        r = dhcp_lease_new(&lease);
+        if (r < 0)
+                return r;
+
+        if (client->client_id_len) {
+                r = dhcp_lease_set_client_id(lease,
+                                             (uint8_t *) &client->client_id,
+                                             client->client_id_len);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease, NULL);
+        if (r != DHCP_OFFER) {
+                log_dhcp_client(client, "received message was not an OFFER, ignoring");
+                return -ENOMSG;
+        }
+
+        lease->next_server = offer->siaddr;
+        lease->address = offer->yiaddr;
+
+        if (lease->lifetime == 0 && client->fallback_lease_lifetime > 0)
+                lease->lifetime = client->fallback_lease_lifetime;
+
+        if (lease->address == 0 ||
+            lease->server_address == 0 ||
+            lease->lifetime == 0) {
+                log_dhcp_client(client, "received lease lacks address, server address or lease lifetime, ignoring");
+                return -ENOMSG;
+        }
+
+        if (!lease->have_subnet_mask) {
+                r = dhcp_lease_set_default_subnet_mask(lease);
+                if (r < 0) {
+                        log_dhcp_client(client,
+                                        "received lease lacks subnet mask, "
+                                        "and a fallback one cannot be generated, ignoring");
+                        return -ENOMSG;
+                }
+        }
+
+        sd_dhcp_lease_unref(client->lease);
+        client->lease = TAKE_PTR(lease);
+
+        if (client_notify(client, SD_DHCP_CLIENT_EVENT_SELECTING) < 0)
+                return -ENOMSG;
+
+        log_dhcp_client(client, "OFFER");
+
+        return 0;
+}
+
+static int client_handle_forcerenew(sd_dhcp_client *client, DHCPMessage *force, size_t len) {
+        int r;
+
+        r = dhcp_option_parse(force, len, NULL, NULL, NULL);
+        if (r != DHCP_FORCERENEW)
+                return -ENOMSG;
+
+        log_dhcp_client(client, "FORCERENEW");
+
+        return 0;
+}
+
+static bool lease_equal(const sd_dhcp_lease *a, const sd_dhcp_lease *b) {
+        if (a->address != b->address)
+                return false;
+
+        if (a->subnet_mask != b->subnet_mask)
+                return false;
+
+        if (a->router_size != b->router_size)
+                return false;
+
+        for (size_t i = 0; i < a->router_size; i++)
+                if (a->router[i].s_addr != b->router[i].s_addr)
+                        return false;
+
+        return true;
+}
+
+static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack, size_t len) {
+        _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL;
+        _cleanup_free_ char *error_message = NULL;
+        int r;
+
+        r = dhcp_lease_new(&lease);
+        if (r < 0)
+                return r;
+
+        if (client->client_id_len) {
+                r = dhcp_lease_set_client_id(lease,
+                                             (uint8_t *) &client->client_id,
+                                             client->client_id_len);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease, &error_message);
+        if (r == DHCP_NAK) {
+                log_dhcp_client(client, "NAK: %s", strna(error_message));
+                return -EADDRNOTAVAIL;
+        }
+
+        if (r != DHCP_ACK) {
+                log_dhcp_client(client, "received message was not an ACK, ignoring");
+                return -ENOMSG;
+        }
+
+        lease->next_server = ack->siaddr;
+
+        lease->address = ack->yiaddr;
+
+        if (lease->address == INADDR_ANY ||
+            lease->server_address == INADDR_ANY ||
+            lease->lifetime == 0) {
+                log_dhcp_client(client, "received lease lacks address, server "
+                                "address or lease lifetime, ignoring");
+                return -ENOMSG;
+        }
+
+        if (lease->subnet_mask == INADDR_ANY) {
+                r = dhcp_lease_set_default_subnet_mask(lease);
+                if (r < 0) {
+                        log_dhcp_client(client,
+                                        "received lease lacks subnet mask, "
+                                        "and a fallback one cannot be generated, ignoring");
+                        return -ENOMSG;
+                }
+        }
+
+        r = SD_DHCP_CLIENT_EVENT_IP_ACQUIRE;
+        if (client->lease) {
+                if (lease_equal(client->lease, lease))
+                        r = SD_DHCP_CLIENT_EVENT_RENEW;
+                else
+                        r = SD_DHCP_CLIENT_EVENT_IP_CHANGE;
+
+                client->lease = sd_dhcp_lease_unref(client->lease);
+        }
+
+        client->lease = TAKE_PTR(lease);
+
+        log_dhcp_client(client, "ACK");
+
+        return r;
+}
+
+static uint64_t client_compute_timeout(sd_dhcp_client *client, uint32_t lifetime, double factor) {
+        assert(client);
+        assert(client->request_sent);
+        assert(lifetime > 0);
+
+        if (lifetime > 3)
+                lifetime -= 3;
+        else
+                lifetime = 0;
+
+        return client->request_sent + (lifetime * USEC_PER_SEC * factor) +
+                + (random_u32() & 0x1fffff);
+}
+
+static int client_set_lease_timeouts(sd_dhcp_client *client) {
+        usec_t time_now;
+        uint64_t lifetime_timeout;
+        uint64_t t2_timeout;
+        uint64_t t1_timeout;
+        char time_string[FORMAT_TIMESPAN_MAX];
+        int r;
+
+        assert(client);
+        assert(client->event);
+        assert(client->lease);
+        assert(client->lease->lifetime);
+
+        /* don't set timers for infinite leases */
+        if (client->lease->lifetime == 0xffffffff) {
+                (void) event_source_disable(client->timeout_t1);
+                (void) event_source_disable(client->timeout_t2);
+                (void) event_source_disable(client->timeout_expire);
+
+                return 0;
+        }
+
+        r = sd_event_now(client->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                return r;
+        assert(client->request_sent <= time_now);
+
+        /* convert the various timeouts from relative (secs) to absolute (usecs) */
+        lifetime_timeout = client_compute_timeout(client, client->lease->lifetime, 1);
+        if (client->lease->t1 > 0 && client->lease->t2 > 0) {
+                /* both T1 and T2 are given */
+                if (client->lease->t1 < client->lease->t2 &&
+                    client->lease->t2 < client->lease->lifetime) {
+                        /* they are both valid */
+                        t2_timeout = client_compute_timeout(client, client->lease->t2, 1);
+                        t1_timeout = client_compute_timeout(client, client->lease->t1, 1);
+                } else {
+                        /* discard both */
+                        t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
+                        client->lease->t2 = (client->lease->lifetime * 7) / 8;
+                        t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
+                        client->lease->t1 = client->lease->lifetime / 2;
+                }
+        } else if (client->lease->t2 > 0 && client->lease->t2 < client->lease->lifetime) {
+                /* only T2 is given, and it is valid */
+                t2_timeout = client_compute_timeout(client, client->lease->t2, 1);
+                t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
+                client->lease->t1 = client->lease->lifetime / 2;
+                if (t2_timeout <= t1_timeout) {
+                        /* the computed T1 would be invalid, so discard T2 */
+                        t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
+                        client->lease->t2 = (client->lease->lifetime * 7) / 8;
+                }
+        } else if (client->lease->t1 > 0 && client->lease->t1 < client->lease->lifetime) {
+                /* only T1 is given, and it is valid */
+                t1_timeout = client_compute_timeout(client, client->lease->t1, 1);
+                t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
+                client->lease->t2 = (client->lease->lifetime * 7) / 8;
+                if (t2_timeout <= t1_timeout) {
+                        /* the computed T2 would be invalid, so discard T1 */
+                        t2_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
+                        client->lease->t2 = client->lease->lifetime / 2;
+                }
+        } else {
+                /* fall back to the default timeouts */
+                t1_timeout = client_compute_timeout(client, client->lease->lifetime, 0.5);
+                client->lease->t1 = client->lease->lifetime / 2;
+                t2_timeout = client_compute_timeout(client, client->lease->lifetime, 7.0 / 8.0);
+                client->lease->t2 = (client->lease->lifetime * 7) / 8;
+        }
+
+        /* arm lifetime timeout */
+        r = event_reset_time(client->event, &client->timeout_expire,
+                             clock_boottime_or_monotonic(),
+                             lifetime_timeout, 10 * USEC_PER_MSEC,
+                             client_timeout_expire, client,
+                             client->event_priority, "dhcp4-lifetime", true);
+        if (r < 0)
+                return r;
+
+        log_dhcp_client(client, "lease expires in %s",
+                        format_timespan(time_string, FORMAT_TIMESPAN_MAX, lifetime_timeout - time_now, USEC_PER_SEC));
+
+        /* don't arm earlier timeouts if this has already expired */
+        if (lifetime_timeout <= time_now)
+                return 0;
+
+        /* arm T2 timeout */
+        r = event_reset_time(client->event, &client->timeout_t2,
+                             clock_boottime_or_monotonic(),
+                             t2_timeout, 10 * USEC_PER_MSEC,
+                             client_timeout_t2, client,
+                             client->event_priority, "dhcp4-t2-timeout", true);
+        if (r < 0)
+                return r;
+
+        log_dhcp_client(client, "T2 expires in %s",
+                        format_timespan(time_string, FORMAT_TIMESPAN_MAX, t2_timeout - time_now, USEC_PER_SEC));
+
+        /* don't arm earlier timeout if this has already expired */
+        if (t2_timeout <= time_now)
+                return 0;
+
+        /* arm T1 timeout */
+        r = event_reset_time(client->event, &client->timeout_t1,
+                             clock_boottime_or_monotonic(),
+                             t1_timeout, 10 * USEC_PER_MSEC,
+                             client_timeout_t1, client,
+                             client->event_priority, "dhcp4-t1-timer", true);
+        if (r < 0)
+                return r;
+
+        log_dhcp_client(client, "T1 expires in %s",
+                        format_timespan(time_string, FORMAT_TIMESPAN_MAX, t1_timeout - time_now, USEC_PER_SEC));
+
+        return 0;
+}
+
+static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message, int len) {
+        DHCP_CLIENT_DONT_DESTROY(client);
+        char time_string[FORMAT_TIMESPAN_MAX];
+        int r = 0, notify_event = 0;
+
+        assert(client);
+        assert(client->event);
+        assert(message);
+
+        switch (client->state) {
+        case DHCP_STATE_SELECTING:
+
+                r = client_handle_offer(client, message, len);
+                if (r >= 0) {
+
+                        client->state = DHCP_STATE_REQUESTING;
+                        client->attempt = 0;
+
+                        r = event_reset_time(client->event, &client->timeout_resend,
+                                             clock_boottime_or_monotonic(),
+                                             0, 0,
+                                             client_timeout_resend, client,
+                                             client->event_priority, "dhcp4-resend-timer", true);
+                        if (r < 0)
+                                goto error;
+                } else if (r == -ENOMSG)
+                        /* invalid message, let's ignore it */
+                        return 0;
+
+                break;
+
+        case DHCP_STATE_REBOOTING:
+        case DHCP_STATE_REQUESTING:
+        case DHCP_STATE_RENEWING:
+        case DHCP_STATE_REBINDING:
+
+                r = client_handle_ack(client, message, len);
+                if (r >= 0) {
+                        client->start_delay = 0;
+                        (void) event_source_disable(client->timeout_resend);
+                        client->receive_message =
+                                sd_event_source_unref(client->receive_message);
+                        client->fd = safe_close(client->fd);
+
+                        if (IN_SET(client->state, DHCP_STATE_REQUESTING,
+                                   DHCP_STATE_REBOOTING))
+                                notify_event = SD_DHCP_CLIENT_EVENT_IP_ACQUIRE;
+                        else if (r != SD_DHCP_CLIENT_EVENT_IP_ACQUIRE)
+                                notify_event = r;
+
+                        client->state = DHCP_STATE_BOUND;
+                        client->attempt = 0;
+
+                        client->last_addr = client->lease->address;
+
+                        r = client_set_lease_timeouts(client);
+                        if (r < 0) {
+                                log_dhcp_client(client, "could not set lease timeouts");
+                                goto error;
+                        }
+
+                        r = dhcp_network_bind_udp_socket(client->ifindex, client->lease->address, client->port, client->ip_service_type);
+                        if (r < 0) {
+                                log_dhcp_client(client, "could not bind UDP socket");
+                                goto error;
+                        }
+
+                        client->fd = r;
+
+                        client_initialize_io_events(client, client_receive_message_udp);
+
+                        if (notify_event) {
+                                client_notify(client, notify_event);
+                                if (client->state == DHCP_STATE_STOPPED)
+                                        return 0;
+                        }
+
+                } else if (r == -EADDRNOTAVAIL) {
+                        /* got a NAK, let's restart the client */
+                        client_notify(client, SD_DHCP_CLIENT_EVENT_EXPIRED);
+
+                        r = client_initialize(client);
+                        if (r < 0)
+                                goto error;
+
+                        r = client_start_delayed(client);
+                        if (r < 0)
+                                goto error;
+
+                        log_dhcp_client(client, "REBOOT in %s", format_timespan(time_string, FORMAT_TIMESPAN_MAX,
+                                                                                client->start_delay, USEC_PER_SEC));
+
+                        client->start_delay = CLAMP(client->start_delay * 2,
+                                                    RESTART_AFTER_NAK_MIN_USEC, RESTART_AFTER_NAK_MAX_USEC);
+
+                        return 0;
+                } else if (r == -ENOMSG)
+                        /* invalid message, let's ignore it */
+                        return 0;
+
+                break;
+
+        case DHCP_STATE_BOUND:
+                r = client_handle_forcerenew(client, message, len);
+                if (r >= 0) {
+                        r = client_timeout_t1(NULL, 0, client);
+                        if (r < 0)
+                                goto error;
+                } else if (r == -ENOMSG)
+                        /* invalid message, let's ignore it */
+                        return 0;
+
+                break;
+
+        case DHCP_STATE_INIT:
+        case DHCP_STATE_INIT_REBOOT:
+
+                break;
+
+        case DHCP_STATE_STOPPED:
+                r = -EINVAL;
+                goto error;
+        }
+
+error:
+        if (r < 0)
+                client_stop(client, r);
+
+        return r;
+}
+
+static int client_receive_message_udp(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata) {
+
+        sd_dhcp_client *client = userdata;
+        _cleanup_free_ DHCPMessage *message = NULL;
+        const uint8_t *expected_chaddr = NULL;
+        uint8_t expected_hlen = 0;
+        ssize_t len, buflen;
+
+        assert(s);
+        assert(client);
+
+        buflen = next_datagram_size_fd(fd);
+        if (buflen == -ENETDOWN)
+                /* the link is down. Don't return an error or the I/O event
+                   source will be disconnected and we won't be able to receive
+                   packets again when the link comes back. */
+                return 0;
+        if (buflen < 0)
+                return buflen;
+
+        message = malloc0(buflen);
+        if (!message)
+                return -ENOMEM;
+
+        len = recv(fd, message, buflen, 0);
+        if (len < 0) {
+                /* see comment above for why we shouldn't error out on ENETDOWN. */
+                if (IN_SET(errno, EAGAIN, EINTR, ENETDOWN))
+                        return 0;
+
+                return log_dhcp_client_errno(client, errno,
+                                             "Could not receive message from UDP socket: %m");
+        }
+        if ((size_t) len < sizeof(DHCPMessage)) {
+                log_dhcp_client(client, "Too small to be a DHCP message: ignoring");
+                return 0;
+        }
+
+        if (be32toh(message->magic) != DHCP_MAGIC_COOKIE) {
+                log_dhcp_client(client, "Not a DHCP message: ignoring");
+                return 0;
+        }
+
+        if (message->op != BOOTREPLY) {
+                log_dhcp_client(client, "Not a BOOTREPLY message: ignoring");
+                return 0;
+        }
+
+        if (message->htype != client->arp_type) {
+                log_dhcp_client(client, "Packet type does not match client type");
+                return 0;
+        }
+
+        if (client->arp_type == ARPHRD_ETHER) {
+                expected_hlen = ETH_ALEN;
+                expected_chaddr = &client->mac_addr[0];
+        }
+
+        if (message->hlen != expected_hlen) {
+                log_dhcp_client(client, "Unexpected packet hlen %d", message->hlen);
+                return 0;
+        }
+
+        if (expected_hlen > 0 && memcmp(&message->chaddr[0], expected_chaddr, expected_hlen)) {
+                log_dhcp_client(client, "Received chaddr does not match expected: ignoring");
+                return 0;
+        }
+
+        if (client->state != DHCP_STATE_BOUND &&
+            be32toh(message->xid) != client->xid) {
+                /* in BOUND state, we may receive FORCERENEW with xid set by server,
+                   so ignore the xid in this case */
+                log_dhcp_client(client, "Received xid (%u) does not match expected (%u): ignoring",
+                                be32toh(message->xid), client->xid);
+                return 0;
+        }
+
+        return client_handle_message(client, message, len);
+}
+
+static int client_receive_message_raw(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata) {
+
+        sd_dhcp_client *client = userdata;
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct tpacket_auxdata))) control;
+        struct iovec iov = {};
+        struct msghdr msg = {
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+        };
+        struct cmsghdr *cmsg;
+        bool checksum = true;
+        ssize_t buflen, len;
+        int r;
+
+        assert(s);
+        assert(client);
+
+        buflen = next_datagram_size_fd(fd);
+        if (buflen == -ENETDOWN)
+                return 0;
+        if (buflen < 0)
+                return buflen;
+
+        packet = malloc0(buflen);
+        if (!packet)
+                return -ENOMEM;
+
+        iov = IOVEC_MAKE(packet, buflen);
+
+        len = recvmsg_safe(fd, &msg, 0);
+        if (IN_SET(len, -EAGAIN, -EINTR, -ENETDOWN))
+                return 0;
+        if (len < 0)
+                return log_dhcp_client_errno(client, len,
+                                             "Could not receive message from raw socket: %m");
+
+        if ((size_t) len < sizeof(DHCPPacket))
+                return 0;
+
+        cmsg = cmsg_find(&msg, SOL_PACKET, PACKET_AUXDATA, CMSG_LEN(sizeof(struct tpacket_auxdata)));
+        if (cmsg) {
+                struct tpacket_auxdata *aux = (struct tpacket_auxdata*) CMSG_DATA(cmsg);
+                checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
+        }
+
+        r = dhcp_packet_verify_headers(packet, len, checksum, client->port);
+        if (r < 0)
+                return 0;
+
+        len -= DHCP_IP_UDP_SIZE;
+
+        return client_handle_message(client, &packet->dhcp, len);
+}
+
+int sd_dhcp_client_send_renew(sd_dhcp_client *client) {
+        assert_return(client, -EINVAL);
+        assert_return(client->fd >= 0, -EINVAL);
+
+        if (!client->lease)
+                return 0;
+
+        client->start_delay = 0;
+        client->attempt = 1;
+        client->state = DHCP_STATE_RENEWING;
+
+        return client_initialize_time_events(client);
+}
+
+int sd_dhcp_client_start(sd_dhcp_client *client) {
+        int r;
+
+        assert_return(client, -EINVAL);
+
+        r = client_initialize(client);
+        if (r < 0)
+                return r;
+
+        /* RFC7844 section 3.3:
+           SHOULD perform a complete four-way handshake, starting with a
+           DHCPDISCOVER, to obtain a new address lease.  If the client can
+           ascertain that this is exactly the same network to which it was
+           previously connected, and if the link-layer address did not change,
+           the client MAY issue a DHCPREQUEST to try to reclaim the current
+           address. */
+        if (client->last_addr && !client->anonymize)
+                client->state = DHCP_STATE_INIT_REBOOT;
+
+        r = client_start(client);
+        if (r >= 0)
+                log_dhcp_client(client, "STARTED on ifindex %i", client->ifindex);
+
+        return r;
+}
+
+int sd_dhcp_client_send_release(sd_dhcp_client *client) {
+        assert_return(client, -EINVAL);
+        assert_return(client->state != DHCP_STATE_STOPPED, -ESTALE);
+        assert_return(client->lease, -EUNATCH);
+
+        _cleanup_free_ DHCPPacket *release = NULL;
+        size_t optoffset, optlen;
+        int r;
+
+        r = client_message_init(client, &release, DHCP_RELEASE, &optlen, &optoffset);
+        if (r < 0)
+                return r;
+
+        /* Fill up release IP and MAC */
+        release->dhcp.ciaddr = client->lease->address;
+        memcpy(&release->dhcp.chaddr, &client->mac_addr, client->mac_addr_len);
+
+        r = dhcp_option_append(&release->dhcp, optlen, &optoffset, 0,
+                               SD_DHCP_OPTION_END, 0, NULL);
+        if (r < 0)
+                return r;
+
+        r = dhcp_network_send_udp_socket(client->fd,
+                                         client->lease->server_address,
+                                         DHCP_PORT_SERVER,
+                                         &release->dhcp,
+                                         sizeof(DHCPMessage) + optoffset);
+        if (r < 0)
+                return r;
+
+        log_dhcp_client(client, "RELEASE");
+
+        return 0;
+}
+
+int sd_dhcp_client_send_decline(sd_dhcp_client *client) {
+        assert_return(client, -EINVAL);
+        assert_return(client->state != DHCP_STATE_STOPPED, -ESTALE);
+        assert_return(client->lease, -EUNATCH);
+
+        _cleanup_free_ DHCPPacket *release = NULL;
+        size_t optoffset, optlen;
+        int r;
+
+        r = client_message_init(client, &release, DHCP_DECLINE, &optlen, &optoffset);
+        if (r < 0)
+                return r;
+
+        release->dhcp.ciaddr = client->lease->address;
+        memcpy(&release->dhcp.chaddr, &client->mac_addr, client->mac_addr_len);
+
+        r = dhcp_option_append(&release->dhcp, optlen, &optoffset, 0,
+                               SD_DHCP_OPTION_END, 0, NULL);
+        if (r < 0)
+                return r;
+
+        r = dhcp_network_send_udp_socket(client->fd,
+                                         client->lease->server_address,
+                                         DHCP_PORT_SERVER,
+                                         &release->dhcp,
+                                         sizeof(DHCPMessage) + optoffset);
+        if (r < 0)
+                return r;
+
+        log_dhcp_client(client, "DECLINE");
+
+        client_stop(client, SD_DHCP_CLIENT_EVENT_STOP);
+
+        if (client->state != DHCP_STATE_STOPPED) {
+                r = sd_dhcp_client_start(client);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int sd_dhcp_client_stop(sd_dhcp_client *client) {
+        if (!client)
+                return 0;
+
+        DHCP_CLIENT_DONT_DESTROY(client);
+
+        client_stop(client, SD_DHCP_CLIENT_EVENT_STOP);
+        client->state = DHCP_STATE_STOPPED;
+
+        return 0;
+}
+
+int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(!client->event, -EBUSY);
+
+        if (event)
+                client->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&client->event);
+                if (r < 0)
+                        return 0;
+        }
+
+        client->event_priority = priority;
+
+        return 0;
+}
+
+int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
+        assert_return(client, -EINVAL);
+
+        client->event = sd_event_unref(client->event);
+
+        return 0;
+}
+
+sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
+        assert_return(client, NULL);
+
+        return client->event;
+}
+
+static sd_dhcp_client *dhcp_client_free(sd_dhcp_client *client) {
+        if (!client)
+                return NULL;
+
+        log_dhcp_client(client, "FREE");
+
+        client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+        client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
+        client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
+        client->timeout_expire = sd_event_source_unref(client->timeout_expire);
+
+        client_initialize(client);
+
+        sd_dhcp_client_detach_event(client);
+
+        sd_dhcp_lease_unref(client->lease);
+
+        set_free(client->req_opts);
+        free(client->hostname);
+        free(client->vendor_class_identifier);
+        free(client->mudurl);
+        client->user_class = strv_free(client->user_class);
+        ordered_hashmap_free(client->extra_options);
+        ordered_hashmap_free(client->vendor_options);
+        return mfree(client);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_client, sd_dhcp_client, dhcp_client_free);
+
+int sd_dhcp_client_new(sd_dhcp_client **ret, int anonymize) {
+        const uint8_t *opts;
+        size_t n_opts;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        _cleanup_(sd_dhcp_client_unrefp) sd_dhcp_client *client = new(sd_dhcp_client, 1);
+        if (!client)
+                return -ENOMEM;
+
+        *client = (sd_dhcp_client) {
+                .n_ref = 1,
+                .state = DHCP_STATE_INIT,
+                .ifindex = -1,
+                .fd = -1,
+                .mtu = DHCP_DEFAULT_MIN_SIZE,
+                .port = DHCP_PORT_CLIENT,
+                .anonymize = !!anonymize,
+                .max_attempts = (uint64_t) -1,
+                .ip_service_type = -1,
+        };
+        /* NOTE: this could be moved to a function. */
+        if (anonymize) {
+                n_opts = ELEMENTSOF(default_req_opts_anonymize);
+                opts = default_req_opts_anonymize;
+        } else {
+                n_opts = ELEMENTSOF(default_req_opts);
+                opts = default_req_opts;
+        }
+
+        for (size_t i = 0; i < n_opts; i++) {
+                r = sd_dhcp_client_set_request_option(client, opts[i]);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = TAKE_PTR(client);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
new file mode 100644
index 0000000..8a138ff
--- /dev/null
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -0,0 +1,1399 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "sd-dhcp-lease.h"
+
+#include "alloc-util.h"
+#include "dhcp-lease-internal.h"
+#include "dhcp-protocol.h"
+#include "dns-domain.h"
+#include "env-file.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "hexdecoct.h"
+#include "hostname-util.h"
+#include "in-addr-util.h"
+#include "network-internal.h"
+#include "parse-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "tmpfile-util.h"
+#include "unaligned.h"
+
+int sd_dhcp_lease_get_address(sd_dhcp_lease *lease, struct in_addr *addr) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (lease->address == 0)
+                return -ENODATA;
+
+        addr->s_addr = lease->address;
+        return 0;
+}
+
+int sd_dhcp_lease_get_broadcast(sd_dhcp_lease *lease, struct in_addr *addr) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (!lease->have_broadcast)
+                return -ENODATA;
+
+        addr->s_addr = lease->broadcast;
+        return 0;
+}
+
+int sd_dhcp_lease_get_lifetime(sd_dhcp_lease *lease, uint32_t *lifetime) {
+        assert_return(lease, -EINVAL);
+        assert_return(lifetime, -EINVAL);
+
+        if (lease->lifetime <= 0)
+                return -ENODATA;
+
+        *lifetime = lease->lifetime;
+        return 0;
+}
+
+int sd_dhcp_lease_get_t1(sd_dhcp_lease *lease, uint32_t *t1) {
+        assert_return(lease, -EINVAL);
+        assert_return(t1, -EINVAL);
+
+        if (lease->t1 <= 0)
+                return -ENODATA;
+
+        *t1 = lease->t1;
+        return 0;
+}
+
+int sd_dhcp_lease_get_t2(sd_dhcp_lease *lease, uint32_t *t2) {
+        assert_return(lease, -EINVAL);
+        assert_return(t2, -EINVAL);
+
+        if (lease->t2 <= 0)
+                return -ENODATA;
+
+        *t2 = lease->t2;
+        return 0;
+}
+
+int sd_dhcp_lease_get_mtu(sd_dhcp_lease *lease, uint16_t *mtu) {
+        assert_return(lease, -EINVAL);
+        assert_return(mtu, -EINVAL);
+
+        if (lease->mtu <= 0)
+                return -ENODATA;
+
+        *mtu = lease->mtu;
+        return 0;
+}
+
+int sd_dhcp_lease_get_servers(
+                sd_dhcp_lease *lease,
+                sd_dhcp_lease_server_type what,
+                const struct in_addr **addr) {
+
+        assert_return(lease, -EINVAL);
+        assert_return(what >= 0, -EINVAL);
+        assert_return(what < _SD_DHCP_LEASE_SERVER_TYPE_MAX, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (lease->servers[what].size <= 0)
+                return -ENODATA;
+
+        *addr = lease->servers[what].addr;
+        return (int) lease->servers[what].size;
+}
+
+int sd_dhcp_lease_get_dns(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        return sd_dhcp_lease_get_servers(lease, SD_DHCP_LEASE_DNS, addr);
+}
+int sd_dhcp_lease_get_ntp(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        return sd_dhcp_lease_get_servers(lease, SD_DHCP_LEASE_NTP, addr);
+}
+int sd_dhcp_lease_get_sip(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        return sd_dhcp_lease_get_servers(lease, SD_DHCP_LEASE_SIP, addr);
+}
+int sd_dhcp_lease_get_pop3(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        return sd_dhcp_lease_get_servers(lease, SD_DHCP_LEASE_POP3, addr);
+}
+int sd_dhcp_lease_get_smtp(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        return sd_dhcp_lease_get_servers(lease, SD_DHCP_LEASE_SMTP, addr);
+}
+int sd_dhcp_lease_get_lpr(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        return sd_dhcp_lease_get_servers(lease, SD_DHCP_LEASE_LPR, addr);
+}
+
+int sd_dhcp_lease_get_domainname(sd_dhcp_lease *lease, const char **domainname) {
+        assert_return(lease, -EINVAL);
+        assert_return(domainname, -EINVAL);
+
+        if (!lease->domainname)
+                return -ENODATA;
+
+        *domainname = lease->domainname;
+        return 0;
+}
+
+int sd_dhcp_lease_get_hostname(sd_dhcp_lease *lease, const char **hostname) {
+        assert_return(lease, -EINVAL);
+        assert_return(hostname, -EINVAL);
+
+        if (!lease->hostname)
+                return -ENODATA;
+
+        *hostname = lease->hostname;
+        return 0;
+}
+
+int sd_dhcp_lease_get_root_path(sd_dhcp_lease *lease, const char **root_path) {
+        assert_return(lease, -EINVAL);
+        assert_return(root_path, -EINVAL);
+
+        if (!lease->root_path)
+                return -ENODATA;
+
+        *root_path = lease->root_path;
+        return 0;
+}
+
+int sd_dhcp_lease_get_router(sd_dhcp_lease *lease, const struct in_addr **addr) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (lease->router_size <= 0)
+                return -ENODATA;
+
+        *addr = lease->router;
+        return (int) lease->router_size;
+}
+
+int sd_dhcp_lease_get_netmask(sd_dhcp_lease *lease, struct in_addr *addr) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (!lease->have_subnet_mask)
+                return -ENODATA;
+
+        addr->s_addr = lease->subnet_mask;
+        return 0;
+}
+
+int sd_dhcp_lease_get_server_identifier(sd_dhcp_lease *lease, struct in_addr *addr) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (lease->server_address == 0)
+                return -ENODATA;
+
+        addr->s_addr = lease->server_address;
+        return 0;
+}
+
+int sd_dhcp_lease_get_next_server(sd_dhcp_lease *lease, struct in_addr *addr) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+
+        if (lease->next_server == 0)
+                return -ENODATA;
+
+        addr->s_addr = lease->next_server;
+        return 0;
+}
+
+/*
+ * The returned routes array must be freed by the caller.
+ * Route objects have the same lifetime of the lease and must not be freed.
+ */
+int sd_dhcp_lease_get_routes(sd_dhcp_lease *lease, sd_dhcp_route ***routes) {
+        sd_dhcp_route **ret;
+        unsigned i;
+
+        assert_return(lease, -EINVAL);
+        assert_return(routes, -EINVAL);
+
+        if (lease->static_route_size <= 0)
+                return -ENODATA;
+
+        ret = new(sd_dhcp_route *, lease->static_route_size);
+        if (!ret)
+                return -ENOMEM;
+
+        for (i = 0; i < lease->static_route_size; i++)
+                ret[i] = &lease->static_route[i];
+
+        *routes = ret;
+        return (int) lease->static_route_size;
+}
+
+int sd_dhcp_lease_get_search_domains(sd_dhcp_lease *lease, char ***domains) {
+        size_t r;
+
+        assert_return(lease, -EINVAL);
+        assert_return(domains, -EINVAL);
+
+        r = strv_length(lease->search_domains);
+        if (r > 0) {
+                *domains = lease->search_domains;
+                return (int) r;
+        }
+
+        return -ENODATA;
+}
+
+int sd_dhcp_lease_get_vendor_specific(sd_dhcp_lease *lease, const void **data, size_t *data_len) {
+        assert_return(lease, -EINVAL);
+        assert_return(data, -EINVAL);
+        assert_return(data_len, -EINVAL);
+
+        if (lease->vendor_specific_len <= 0)
+                return -ENODATA;
+
+        *data = lease->vendor_specific;
+        *data_len = lease->vendor_specific_len;
+        return 0;
+}
+
+static sd_dhcp_lease *dhcp_lease_free(sd_dhcp_lease *lease) {
+        assert(lease);
+
+        while (lease->private_options) {
+                struct sd_dhcp_raw_option *option = lease->private_options;
+
+                LIST_REMOVE(options, lease->private_options, option);
+
+                free(option->data);
+                free(option);
+        }
+
+        free(lease->root_path);
+        free(lease->router);
+        free(lease->timezone);
+        free(lease->hostname);
+        free(lease->domainname);
+
+        for (sd_dhcp_lease_server_type i = 0; i < _SD_DHCP_LEASE_SERVER_TYPE_MAX; i++)
+                free(lease->servers[i].addr);
+
+        free(lease->static_route);
+        free(lease->client_id);
+        free(lease->vendor_specific);
+        strv_free(lease->search_domains);
+        return mfree(lease);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_lease, sd_dhcp_lease, dhcp_lease_free);
+
+static int lease_parse_u32(const uint8_t *option, size_t len, uint32_t *ret, uint32_t min) {
+        assert(option);
+        assert(ret);
+
+        if (len != 4)
+                return -EINVAL;
+
+        *ret = unaligned_read_be32((be32_t*) option);
+        if (*ret < min)
+                *ret = min;
+
+        return 0;
+}
+
+static int lease_parse_u16(const uint8_t *option, size_t len, uint16_t *ret, uint16_t min) {
+        assert(option);
+        assert(ret);
+
+        if (len != 2)
+                return -EINVAL;
+
+        *ret = unaligned_read_be16((be16_t*) option);
+        if (*ret < min)
+                *ret = min;
+
+        return 0;
+}
+
+static int lease_parse_be32(const uint8_t *option, size_t len, be32_t *ret) {
+        assert(option);
+        assert(ret);
+
+        if (len != 4)
+                return -EINVAL;
+
+        memcpy(ret, option, 4);
+        return 0;
+}
+
+static int lease_parse_string(const uint8_t *option, size_t len, char **ret) {
+        assert(option);
+        assert(ret);
+
+        if (len <= 0)
+                *ret = mfree(*ret);
+        else {
+                char *string;
+
+                /*
+                 * One trailing NUL byte is OK, we don't mind. See:
+                 * https://github.com/systemd/systemd/issues/1337
+                 */
+                if (memchr(option, 0, len - 1))
+                        return -EINVAL;
+
+                string = memdup_suffix0((const char *) option, len);
+                if (!string)
+                        return -ENOMEM;
+
+                free_and_replace(*ret, string);
+        }
+
+        return 0;
+}
+
+static int lease_parse_domain(const uint8_t *option, size_t len, char **ret) {
+        _cleanup_free_ char *name = NULL, *normalized = NULL;
+        int r;
+
+        assert(option);
+        assert(ret);
+
+        r = lease_parse_string(option, len, &name);
+        if (r < 0)
+                return r;
+        if (!name) {
+                *ret = mfree(*ret);
+                return 0;
+        }
+
+        r = dns_name_normalize(name, 0, &normalized);
+        if (r < 0)
+                return r;
+
+        if (is_localhost(normalized))
+                return -EINVAL;
+
+        if (dns_name_is_root(normalized))
+                return -EINVAL;
+
+        free_and_replace(*ret, normalized);
+
+        return 0;
+}
+
+static int lease_parse_in_addrs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *n_ret) {
+        assert(option || len == 0);
+        assert(ret);
+        assert(n_ret);
+
+        if (len <= 0) {
+                *ret = mfree(*ret);
+                *n_ret = 0;
+        } else {
+                size_t n_addresses;
+                struct in_addr *addresses;
+
+                if (len % 4 != 0)
+                        return -EINVAL;
+
+                n_addresses = len / 4;
+
+                addresses = newdup(struct in_addr, option, n_addresses);
+                if (!addresses)
+                        return -ENOMEM;
+
+                free(*ret);
+                *ret = addresses;
+                *n_ret = n_addresses;
+        }
+
+        return 0;
+}
+
+static int lease_parse_sip_server(const uint8_t *option, size_t len, struct in_addr **ret, size_t *n_ret) {
+        assert(option || len == 0);
+        assert(ret);
+        assert(n_ret);
+
+        if (len <= 0)
+                return -EINVAL;
+
+        /* The SIP record is like the other, regular server records, but prefixed with a single "encoding"
+         * byte that is either 0 or 1. We only support it to be 1 for now. Let's drop it and parse it like
+         * the other fields */
+
+        if (option[0] != 1) { /* We only support IP address encoding for now */
+                *ret = mfree(*ret);
+                *n_ret = 0;
+                return 0;
+        }
+
+        return lease_parse_in_addrs(option + 1, len - 1, ret, n_ret);
+}
+
+static int lease_parse_routes(
+                const uint8_t *option, size_t len,
+                struct sd_dhcp_route **routes, size_t *routes_size, size_t *routes_allocated) {
+
+        struct in_addr addr;
+
+        assert(option || len <= 0);
+        assert(routes);
+        assert(routes_size);
+        assert(routes_allocated);
+
+        if (len <= 0)
+                return 0;
+
+        if (len % 8 != 0)
+                return -EINVAL;
+
+        if (!GREEDY_REALLOC(*routes, *routes_allocated, *routes_size + (len / 8)))
+                return -ENOMEM;
+
+        while (len >= 8) {
+                struct sd_dhcp_route *route = *routes + *routes_size;
+                int r;
+
+                route->option = SD_DHCP_OPTION_STATIC_ROUTE;
+                r = in4_addr_default_prefixlen((struct in_addr*) option, &route->dst_prefixlen);
+                if (r < 0) {
+                        log_debug("Failed to determine destination prefix length from class based IP, ignoring");
+                        continue;
+                }
+
+                assert_se(lease_parse_be32(option, 4, &addr.s_addr) >= 0);
+                route->dst_addr = inet_makeaddr(inet_netof(addr), 0);
+                option += 4;
+
+                assert_se(lease_parse_be32(option, 4, &route->gw_addr.s_addr) >= 0);
+                option += 4;
+
+                len -= 8;
+                (*routes_size)++;
+        }
+
+        return 0;
+}
+
+/* parses RFC3442 Classless Static Route Option */
+static int lease_parse_classless_routes(
+                const uint8_t *option, size_t len,
+                struct sd_dhcp_route **routes, size_t *routes_size, size_t *routes_allocated) {
+
+        assert(option || len <= 0);
+        assert(routes);
+        assert(routes_size);
+        assert(routes_allocated);
+
+        if (len <= 0)
+                return 0;
+
+        /* option format: (subnet-mask-width significant-subnet-octets gateway-ip)*  */
+
+        while (len > 0) {
+                uint8_t dst_octets;
+                struct sd_dhcp_route *route;
+
+                if (!GREEDY_REALLOC(*routes, *routes_allocated, *routes_size + 1))
+                        return -ENOMEM;
+
+                route = *routes + *routes_size;
+                route->option = SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE;
+
+                dst_octets = (*option == 0 ? 0 : ((*option - 1) / 8) + 1);
+                route->dst_prefixlen = *option;
+                option++;
+                len--;
+
+                /* can't have more than 4 octets in IPv4 */
+                if (dst_octets > 4 || len < dst_octets)
+                        return -EINVAL;
+
+                route->dst_addr.s_addr = 0;
+                memcpy(&route->dst_addr.s_addr, option, dst_octets);
+                option += dst_octets;
+                len -= dst_octets;
+
+                if (len < 4)
+                        return -EINVAL;
+
+                assert_se(lease_parse_be32(option, 4, &route->gw_addr.s_addr) >= 0);
+                option += 4;
+                len -= 4;
+
+                (*routes_size)++;
+        }
+
+        return 0;
+}
+
+int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void *userdata) {
+        sd_dhcp_lease *lease = userdata;
+        int r;
+
+        assert(lease);
+
+        switch(code) {
+
+        case SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
+                r = lease_parse_u32(option, len, &lease->lifetime, 1);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse lease time, ignoring: %m");
+
+                break;
+
+        case SD_DHCP_OPTION_SERVER_IDENTIFIER:
+                r = lease_parse_be32(option, len, &lease->server_address);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse server identifier, ignoring: %m");
+
+                break;
+
+        case SD_DHCP_OPTION_SUBNET_MASK:
+                r = lease_parse_be32(option, len, &lease->subnet_mask);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse subnet mask, ignoring: %m");
+                else
+                        lease->have_subnet_mask = true;
+                break;
+
+        case SD_DHCP_OPTION_BROADCAST:
+                r = lease_parse_be32(option, len, &lease->broadcast);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse broadcast address, ignoring: %m");
+                else
+                        lease->have_broadcast = true;
+                break;
+
+        case SD_DHCP_OPTION_ROUTER:
+                r = lease_parse_in_addrs(option, len, &lease->router, &lease->router_size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse router addresses, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_DOMAIN_NAME_SERVER:
+                r = lease_parse_in_addrs(option, len, &lease->servers[SD_DHCP_LEASE_DNS].addr, &lease->servers[SD_DHCP_LEASE_DNS].size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse DNS server, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_NTP_SERVER:
+                r = lease_parse_in_addrs(option, len, &lease->servers[SD_DHCP_LEASE_NTP].addr, &lease->servers[SD_DHCP_LEASE_NTP].size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse NTP server, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_SIP_SERVER:
+                r = lease_parse_sip_server(option, len, &lease->servers[SD_DHCP_LEASE_SIP].addr, &lease->servers[SD_DHCP_LEASE_SIP].size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse SIP server, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_POP3_SERVER:
+                r = lease_parse_in_addrs(option, len, &lease->servers[SD_DHCP_LEASE_POP3].addr, &lease->servers[SD_DHCP_LEASE_POP3].size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse POP3 server, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_SMTP_SERVER:
+                r = lease_parse_in_addrs(option, len, &lease->servers[SD_DHCP_LEASE_SMTP].addr, &lease->servers[SD_DHCP_LEASE_SMTP].size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse SMTP server, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_LPR_SERVER:
+                r = lease_parse_in_addrs(option, len, &lease->servers[SD_DHCP_LEASE_LPR].addr, &lease->servers[SD_DHCP_LEASE_LPR].size);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse LPR server, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_STATIC_ROUTE:
+                r = lease_parse_routes(option, len, &lease->static_route, &lease->static_route_size, &lease->static_route_allocated);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse static routes, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_INTERFACE_MTU:
+                r = lease_parse_u16(option, len, &lease->mtu, 68);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse MTU, ignoring: %m");
+                if (lease->mtu < DHCP_DEFAULT_MIN_SIZE) {
+                        log_debug("MTU value of %" PRIu16 " too small. Using default MTU value of %d instead.", lease->mtu, DHCP_DEFAULT_MIN_SIZE);
+                        lease->mtu = DHCP_DEFAULT_MIN_SIZE;
+                }
+
+                break;
+
+        case SD_DHCP_OPTION_DOMAIN_NAME:
+                r = lease_parse_domain(option, len, &lease->domainname);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to parse domain name, ignoring: %m");
+                        return 0;
+                }
+
+                break;
+
+        case SD_DHCP_OPTION_DOMAIN_SEARCH_LIST:
+                r = dhcp_lease_parse_search_domains(option, len, &lease->search_domains);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse Domain Search List, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_HOST_NAME:
+                r = lease_parse_domain(option, len, &lease->hostname);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to parse hostname, ignoring: %m");
+                        return 0;
+                }
+
+                break;
+
+        case SD_DHCP_OPTION_ROOT_PATH:
+                r = lease_parse_string(option, len, &lease->root_path);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse root path, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_RENEWAL_T1_TIME:
+                r = lease_parse_u32(option, len, &lease->t1, 1);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse T1 time, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_REBINDING_T2_TIME:
+                r = lease_parse_u32(option, len, &lease->t2, 1);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse T2 time, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE:
+                r = lease_parse_classless_routes(
+                                option, len,
+                                &lease->static_route,
+                                &lease->static_route_size,
+                                &lease->static_route_allocated);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse classless routes, ignoring: %m");
+                break;
+
+        case SD_DHCP_OPTION_NEW_TZDB_TIMEZONE: {
+                _cleanup_free_ char *tz = NULL;
+
+                r = lease_parse_string(option, len, &tz);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to parse timezone option, ignoring: %m");
+                        return 0;
+                }
+
+                if (!timezone_is_valid(tz, LOG_DEBUG)) {
+                        log_debug_errno(r, "Timezone is not valid, ignoring: %m");
+                        return 0;
+                }
+
+                free_and_replace(lease->timezone, tz);
+
+                break;
+        }
+
+        case SD_DHCP_OPTION_VENDOR_SPECIFIC:
+
+                if (len <= 0)
+                        lease->vendor_specific = mfree(lease->vendor_specific);
+                else {
+                        void *p;
+
+                        p = memdup(option, len);
+                        if (!p)
+                                return -ENOMEM;
+
+                        free(lease->vendor_specific);
+                        lease->vendor_specific = p;
+                }
+
+                lease->vendor_specific_len = len;
+                break;
+
+        case SD_DHCP_OPTION_PRIVATE_BASE ... SD_DHCP_OPTION_PRIVATE_LAST:
+                r = dhcp_lease_insert_private_option(lease, code, option, len);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        default:
+                log_debug("Ignoring option DHCP option %"PRIu8" while parsing.", code);
+                break;
+        }
+
+        return 0;
+}
+
+/* Parses compressed domain names. */
+int dhcp_lease_parse_search_domains(const uint8_t *option, size_t len, char ***domains) {
+        _cleanup_strv_free_ char **names = NULL;
+        size_t pos = 0, cnt = 0;
+        int r;
+
+        assert(domains);
+        assert_return(option && len > 0, -ENODATA);
+
+        while (pos < len) {
+                _cleanup_free_ char *name = NULL;
+                size_t n = 0, allocated = 0;
+                size_t jump_barrier = pos, next_chunk = 0;
+                bool first = true;
+
+                for (;;) {
+                        uint8_t c;
+                        c = option[pos++];
+
+                        if (c == 0) {
+                                /* End of name */
+                                break;
+                        } else if (c <= 63) {
+                                const char *label;
+
+                                /* Literal label */
+                                label = (const char*) (option + pos);
+                                pos += c;
+                                if (pos >= len)
+                                        return -EBADMSG;
+
+                                if (!GREEDY_REALLOC(name, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
+                                        return -ENOMEM;
+
+                                if (first)
+                                        first = false;
+                                else
+                                        name[n++] = '.';
+
+                                r = dns_label_escape(label, c, name + n, DNS_LABEL_ESCAPED_MAX);
+                                if (r < 0)
+                                        return r;
+
+                                n += r;
+                        } else if (FLAGS_SET(c, 0xc0)) {
+                                /* Pointer */
+
+                                uint8_t d;
+                                uint16_t ptr;
+
+                                if (pos >= len)
+                                        return -EBADMSG;
+
+                                d = option[pos++];
+                                ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d;
+
+                                /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */
+                                if (ptr >= jump_barrier)
+                                        return -EBADMSG;
+                                jump_barrier = ptr;
+
+                                /* Save current location so we don't end up re-parsing what's parsed so far. */
+                                if (next_chunk == 0)
+                                        next_chunk = pos;
+
+                                pos = ptr;
+                        } else
+                                return -EBADMSG;
+                }
+
+                if (!GREEDY_REALLOC(name, allocated, n + 1))
+                        return -ENOMEM;
+                name[n] = 0;
+
+                r = strv_extend(&names, name);
+                if (r < 0)
+                        return r;
+
+                cnt++;
+
+                if (next_chunk != 0)
+                      pos = next_chunk;
+        }
+
+        *domains = TAKE_PTR(names);
+
+        return cnt;
+}
+
+int dhcp_lease_insert_private_option(sd_dhcp_lease *lease, uint8_t tag, const void *data, uint8_t len) {
+        struct sd_dhcp_raw_option *cur, *option;
+
+        assert(lease);
+
+        LIST_FOREACH(options, cur, lease->private_options) {
+                if (tag < cur->tag)
+                        break;
+                if (tag == cur->tag) {
+                        log_debug("Ignoring duplicate option, tagged %i.", tag);
+                        return 0;
+                }
+        }
+
+        option = new(struct sd_dhcp_raw_option, 1);
+        if (!option)
+                return -ENOMEM;
+
+        option->tag = tag;
+        option->length = len;
+        option->data = memdup(data, len);
+        if (!option->data) {
+                free(option);
+                return -ENOMEM;
+        }
+
+        LIST_INSERT_BEFORE(options, lease->private_options, cur, option);
+        return 0;
+}
+
+int dhcp_lease_new(sd_dhcp_lease **ret) {
+        sd_dhcp_lease *lease;
+
+        lease = new0(sd_dhcp_lease, 1);
+        if (!lease)
+                return -ENOMEM;
+
+        lease->n_ref = 1;
+
+        *ret = lease;
+        return 0;
+}
+
+int dhcp_lease_save(sd_dhcp_lease *lease, const char *lease_file) {
+        _cleanup_free_ char *temp_path = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        struct sd_dhcp_raw_option *option;
+        struct in_addr address;
+        const struct in_addr *addresses;
+        const void *client_id, *data;
+        size_t client_id_len, data_len;
+        char sbuf[INET_ADDRSTRLEN];
+        const char *string;
+        uint16_t mtu;
+        _cleanup_free_ sd_dhcp_route **routes = NULL;
+        char **search_domains = NULL;
+        uint32_t t1, t2, lifetime;
+        int r;
+
+        assert(lease);
+        assert(lease_file);
+
+        r = fopen_temporary(lease_file, &f, &temp_path);
+        if (r < 0)
+                goto fail;
+
+        (void) fchmod(fileno(f), 0644);
+
+        fprintf(f,
+                "# This is private data. Do not parse.\n");
+
+        r = sd_dhcp_lease_get_address(lease, &address);
+        if (r >= 0)
+                fprintf(f, "ADDRESS=%s\n", inet_ntop(AF_INET, &address, sbuf, sizeof(sbuf)));
+
+        r = sd_dhcp_lease_get_netmask(lease, &address);
+        if (r >= 0)
+                fprintf(f, "NETMASK=%s\n", inet_ntop(AF_INET, &address, sbuf, sizeof(sbuf)));
+
+        r = sd_dhcp_lease_get_router(lease, &addresses);
+        if (r > 0) {
+                fputs("ROUTER=", f);
+                serialize_in_addrs(f, addresses, r, false, NULL);
+                fputc('\n', f);
+        }
+
+        r = sd_dhcp_lease_get_server_identifier(lease, &address);
+        if (r >= 0)
+                fprintf(f, "SERVER_ADDRESS=%s\n", inet_ntop(AF_INET, &address, sbuf, sizeof(sbuf)));
+
+        r = sd_dhcp_lease_get_next_server(lease, &address);
+        if (r >= 0)
+                fprintf(f, "NEXT_SERVER=%s\n", inet_ntop(AF_INET, &address, sbuf, sizeof(sbuf)));
+
+        r = sd_dhcp_lease_get_broadcast(lease, &address);
+        if (r >= 0)
+                fprintf(f, "BROADCAST=%s\n", inet_ntop(AF_INET, &address, sbuf, sizeof(sbuf)));
+
+        r = sd_dhcp_lease_get_mtu(lease, &mtu);
+        if (r >= 0)
+                fprintf(f, "MTU=%" PRIu16 "\n", mtu);
+
+        r = sd_dhcp_lease_get_t1(lease, &t1);
+        if (r >= 0)
+                fprintf(f, "T1=%" PRIu32 "\n", t1);
+
+        r = sd_dhcp_lease_get_t2(lease, &t2);
+        if (r >= 0)
+                fprintf(f, "T2=%" PRIu32 "\n", t2);
+
+        r = sd_dhcp_lease_get_lifetime(lease, &lifetime);
+        if (r >= 0)
+                fprintf(f, "LIFETIME=%" PRIu32 "\n", lifetime);
+
+        r = sd_dhcp_lease_get_dns(lease, &addresses);
+        if (r > 0) {
+                fputs("DNS=", f);
+                serialize_in_addrs(f, addresses, r, false, NULL);
+                fputc('\n', f);
+        }
+
+        r = sd_dhcp_lease_get_ntp(lease, &addresses);
+        if (r > 0) {
+                fputs("NTP=", f);
+                serialize_in_addrs(f, addresses, r, false, NULL);
+                fputc('\n', f);
+        }
+
+        r = sd_dhcp_lease_get_sip(lease, &addresses);
+        if (r > 0) {
+                fputs("SIP=", f);
+                serialize_in_addrs(f, addresses, r, false, NULL);
+                fputc('\n', f);
+        }
+
+        r = sd_dhcp_lease_get_domainname(lease, &string);
+        if (r >= 0)
+                fprintf(f, "DOMAINNAME=%s\n", string);
+
+        r = sd_dhcp_lease_get_search_domains(lease, &search_domains);
+        if (r > 0) {
+                fputs("DOMAIN_SEARCH_LIST=", f);
+                fputstrv(f, search_domains, NULL, NULL);
+                fputc('\n', f);
+        }
+
+        r = sd_dhcp_lease_get_hostname(lease, &string);
+        if (r >= 0)
+                fprintf(f, "HOSTNAME=%s\n", string);
+
+        r = sd_dhcp_lease_get_root_path(lease, &string);
+        if (r >= 0)
+                fprintf(f, "ROOT_PATH=%s\n", string);
+
+        r = sd_dhcp_lease_get_routes(lease, &routes);
+        if (r > 0)
+                serialize_dhcp_routes(f, "ROUTES", routes, r);
+
+        r = sd_dhcp_lease_get_timezone(lease, &string);
+        if (r >= 0)
+                fprintf(f, "TIMEZONE=%s\n", string);
+
+        r = sd_dhcp_lease_get_client_id(lease, &client_id, &client_id_len);
+        if (r >= 0) {
+                _cleanup_free_ char *client_id_hex = NULL;
+
+                client_id_hex = hexmem(client_id, client_id_len);
+                if (!client_id_hex) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+                fprintf(f, "CLIENTID=%s\n", client_id_hex);
+        }
+
+        r = sd_dhcp_lease_get_vendor_specific(lease, &data, &data_len);
+        if (r >= 0) {
+                _cleanup_free_ char *option_hex = NULL;
+
+                option_hex = hexmem(data, data_len);
+                if (!option_hex) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+                fprintf(f, "VENDOR_SPECIFIC=%s\n", option_hex);
+        }
+
+        LIST_FOREACH(options, option, lease->private_options) {
+                char key[STRLEN("OPTION_000")+1];
+
+                xsprintf(key, "OPTION_%" PRIu8, option->tag);
+                r = serialize_dhcp_option(f, key, option->data, option->length);
+                if (r < 0)
+                        goto fail;
+        }
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                goto fail;
+
+        if (rename(temp_path, lease_file) < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        return 0;
+
+fail:
+        if (temp_path)
+                (void) unlink(temp_path);
+
+        return log_error_errno(r, "Failed to save lease data %s: %m", lease_file);
+}
+
+int dhcp_lease_load(sd_dhcp_lease **ret, const char *lease_file) {
+
+        _cleanup_(sd_dhcp_lease_unrefp) sd_dhcp_lease *lease = NULL;
+        _cleanup_free_ char
+                *address = NULL,
+                *router = NULL,
+                *netmask = NULL,
+                *server_address = NULL,
+                *next_server = NULL,
+                *broadcast = NULL,
+                *dns = NULL,
+                *ntp = NULL,
+                *sip = NULL,
+                *pop3 = NULL,
+                *smtp = NULL,
+                *lpr = NULL,
+                *mtu = NULL,
+                *routes = NULL,
+                *domains = NULL,
+                *client_id_hex = NULL,
+                *vendor_specific_hex = NULL,
+                *lifetime = NULL,
+                *t1 = NULL,
+                *t2 = NULL,
+                *options[SD_DHCP_OPTION_PRIVATE_LAST - SD_DHCP_OPTION_PRIVATE_BASE + 1] = {};
+
+        int r, i;
+
+        assert(lease_file);
+        assert(ret);
+
+        r = dhcp_lease_new(&lease);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, lease_file,
+                           "ADDRESS", &address,
+                           "ROUTER", &router,
+                           "NETMASK", &netmask,
+                           "SERVER_ADDRESS", &server_address,
+                           "NEXT_SERVER", &next_server,
+                           "BROADCAST", &broadcast,
+                           "DNS", &dns,
+                           "NTP", &ntp,
+                           "SIP", &sip,
+                           "POP3", &pop3,
+                           "SMTP", &smtp,
+                           "LPR", &lpr,
+                           "MTU", &mtu,
+                           "DOMAINNAME", &lease->domainname,
+                           "HOSTNAME", &lease->hostname,
+                           "DOMAIN_SEARCH_LIST", &domains,
+                           "ROOT_PATH", &lease->root_path,
+                           "ROUTES", &routes,
+                           "CLIENTID", &client_id_hex,
+                           "TIMEZONE", &lease->timezone,
+                           "VENDOR_SPECIFIC", &vendor_specific_hex,
+                           "LIFETIME", &lifetime,
+                           "T1", &t1,
+                           "T2", &t2,
+                           "OPTION_224", &options[0],
+                           "OPTION_225", &options[1],
+                           "OPTION_226", &options[2],
+                           "OPTION_227", &options[3],
+                           "OPTION_228", &options[4],
+                           "OPTION_229", &options[5],
+                           "OPTION_230", &options[6],
+                           "OPTION_231", &options[7],
+                           "OPTION_232", &options[8],
+                           "OPTION_233", &options[9],
+                           "OPTION_234", &options[10],
+                           "OPTION_235", &options[11],
+                           "OPTION_236", &options[12],
+                           "OPTION_237", &options[13],
+                           "OPTION_238", &options[14],
+                           "OPTION_239", &options[15],
+                           "OPTION_240", &options[16],
+                           "OPTION_241", &options[17],
+                           "OPTION_242", &options[18],
+                           "OPTION_243", &options[19],
+                           "OPTION_244", &options[20],
+                           "OPTION_245", &options[21],
+                           "OPTION_246", &options[22],
+                           "OPTION_247", &options[23],
+                           "OPTION_248", &options[24],
+                           "OPTION_249", &options[25],
+                           "OPTION_250", &options[26],
+                           "OPTION_251", &options[27],
+                           "OPTION_252", &options[28],
+                           "OPTION_253", &options[29],
+                           "OPTION_254", &options[30]);
+        if (r < 0)
+                return r;
+
+        if (address) {
+                r = inet_pton(AF_INET, address, &lease->address);
+                if (r <= 0)
+                        log_debug("Failed to parse address %s, ignoring.", address);
+        }
+
+        if (router) {
+                r = deserialize_in_addrs(&lease->router, router);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize router addresses %s, ignoring: %m", router);
+                else
+                        lease->router_size = r;
+        }
+
+        if (netmask) {
+                r = inet_pton(AF_INET, netmask, &lease->subnet_mask);
+                if (r <= 0)
+                        log_debug("Failed to parse netmask %s, ignoring.", netmask);
+                else
+                        lease->have_subnet_mask = true;
+        }
+
+        if (server_address) {
+                r = inet_pton(AF_INET, server_address, &lease->server_address);
+                if (r <= 0)
+                        log_debug("Failed to parse server address %s, ignoring.", server_address);
+        }
+
+        if (next_server) {
+                r = inet_pton(AF_INET, next_server, &lease->next_server);
+                if (r <= 0)
+                        log_debug("Failed to parse next server %s, ignoring.", next_server);
+        }
+
+        if (broadcast) {
+                r = inet_pton(AF_INET, broadcast, &lease->broadcast);
+                if (r <= 0)
+                        log_debug("Failed to parse broadcast address %s, ignoring.", broadcast);
+                else
+                        lease->have_broadcast = true;
+        }
+
+        if (dns) {
+                r = deserialize_in_addrs(&lease->servers[SD_DHCP_LEASE_DNS].addr, dns);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize DNS servers %s, ignoring: %m", dns);
+                else
+                        lease->servers[SD_DHCP_LEASE_DNS].size = r;
+        }
+
+        if (ntp) {
+                r = deserialize_in_addrs(&lease->servers[SD_DHCP_LEASE_NTP].addr, ntp);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize NTP servers %s, ignoring: %m", ntp);
+                else
+                        lease->servers[SD_DHCP_LEASE_NTP].size = r;
+        }
+
+        if (sip) {
+                r = deserialize_in_addrs(&lease->servers[SD_DHCP_LEASE_SIP].addr, sip);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize SIP servers %s, ignoring: %m", sip);
+                else
+                        lease->servers[SD_DHCP_LEASE_SIP].size = r;
+        }
+
+        if (pop3) {
+                r = deserialize_in_addrs(&lease->servers[SD_DHCP_LEASE_POP3].addr, pop3);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize POP3 server %s, ignoring: %m", pop3);
+                else
+                        lease->servers[SD_DHCP_LEASE_POP3].size = r;
+        }
+
+        if (smtp) {
+                r = deserialize_in_addrs(&lease->servers[SD_DHCP_LEASE_SMTP].addr, smtp);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize SMTP server %s, ignoring: %m", smtp);
+                else
+                        lease->servers[SD_DHCP_LEASE_SMTP].size = r;
+        }
+
+        if (lpr) {
+                r = deserialize_in_addrs(&lease->servers[SD_DHCP_LEASE_LPR].addr, lpr);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to deserialize LPR server %s, ignoring: %m", lpr);
+                else
+                        lease->servers[SD_DHCP_LEASE_LPR].size = r;
+        }
+
+        if (mtu) {
+                r = safe_atou16(mtu, &lease->mtu);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse MTU %s, ignoring: %m", mtu);
+        }
+
+        if (domains) {
+                _cleanup_strv_free_ char **a = NULL;
+                a = strv_split(domains, " ");
+                if (!a)
+                        return -ENOMEM;
+
+                if (!strv_isempty(a))
+                        lease->search_domains = TAKE_PTR(a);
+        }
+
+        if (routes) {
+                r = deserialize_dhcp_routes(
+                                &lease->static_route,
+                                &lease->static_route_size,
+                                &lease->static_route_allocated,
+                                routes);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse DHCP routes %s, ignoring: %m", routes);
+        }
+
+        if (lifetime) {
+                r = safe_atou32(lifetime, &lease->lifetime);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse lifetime %s, ignoring: %m", lifetime);
+        }
+
+        if (t1) {
+                r = safe_atou32(t1, &lease->t1);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse T1 %s, ignoring: %m", t1);
+        }
+
+        if (t2) {
+                r = safe_atou32(t2, &lease->t2);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse T2 %s, ignoring: %m", t2);
+        }
+
+        if (client_id_hex) {
+                r = unhexmem(client_id_hex, (size_t) -1, &lease->client_id, &lease->client_id_len);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse client ID %s, ignoring: %m", client_id_hex);
+        }
+
+        if (vendor_specific_hex) {
+                r = unhexmem(vendor_specific_hex, (size_t) -1, &lease->vendor_specific, &lease->vendor_specific_len);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse vendor specific data %s, ignoring: %m", vendor_specific_hex);
+        }
+
+        for (i = 0; i <= SD_DHCP_OPTION_PRIVATE_LAST - SD_DHCP_OPTION_PRIVATE_BASE; i++) {
+                _cleanup_free_ void *data = NULL;
+                size_t len;
+
+                if (!options[i])
+                        continue;
+
+                r = unhexmem(options[i], (size_t) -1, &data, &len);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to parse private DHCP option %s, ignoring: %m", options[i]);
+                        continue;
+                }
+
+                r = dhcp_lease_insert_private_option(lease, SD_DHCP_OPTION_PRIVATE_BASE + i, data, len);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = TAKE_PTR(lease);
+
+        return 0;
+}
+
+int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease) {
+        struct in_addr address, mask;
+        int r;
+
+        assert(lease);
+
+        if (lease->address == 0)
+                return -ENODATA;
+
+        address.s_addr = lease->address;
+
+        /* fall back to the default subnet masks based on address class */
+        r = in4_addr_default_subnet_mask(&address, &mask);
+        if (r < 0)
+                return r;
+
+        lease->subnet_mask = mask.s_addr;
+        lease->have_subnet_mask = true;
+
+        return 0;
+}
+
+int sd_dhcp_lease_get_client_id(sd_dhcp_lease *lease, const void **client_id, size_t *client_id_len) {
+        assert_return(lease, -EINVAL);
+        assert_return(client_id, -EINVAL);
+        assert_return(client_id_len, -EINVAL);
+
+        if (!lease->client_id)
+                return -ENODATA;
+
+        *client_id = lease->client_id;
+        *client_id_len = lease->client_id_len;
+
+        return 0;
+}
+
+int dhcp_lease_set_client_id(sd_dhcp_lease *lease, const void *client_id, size_t client_id_len) {
+        assert_return(lease, -EINVAL);
+        assert_return(client_id || client_id_len <= 0, -EINVAL);
+
+        if (client_id_len <= 0)
+                lease->client_id = mfree(lease->client_id);
+        else {
+                void *p;
+
+                p = memdup(client_id, client_id_len);
+                if (!p)
+                        return -ENOMEM;
+
+                free(lease->client_id);
+                lease->client_id = p;
+                lease->client_id_len = client_id_len;
+        }
+
+        return 0;
+}
+
+int sd_dhcp_lease_get_timezone(sd_dhcp_lease *lease, const char **tz) {
+        assert_return(lease, -EINVAL);
+        assert_return(tz, -EINVAL);
+
+        if (!lease->timezone)
+                return -ENODATA;
+
+        *tz = lease->timezone;
+        return 0;
+}
+
+int sd_dhcp_route_get_destination(sd_dhcp_route *route, struct in_addr *destination) {
+        assert_return(route, -EINVAL);
+        assert_return(destination, -EINVAL);
+
+        *destination = route->dst_addr;
+        return 0;
+}
+
+int sd_dhcp_route_get_destination_prefix_length(sd_dhcp_route *route, uint8_t *length) {
+        assert_return(route, -EINVAL);
+        assert_return(length, -EINVAL);
+
+        *length = route->dst_prefixlen;
+        return 0;
+}
+
+int sd_dhcp_route_get_gateway(sd_dhcp_route *route, struct in_addr *gateway) {
+        assert_return(route, -EINVAL);
+        assert_return(gateway, -EINVAL);
+
+        *gateway = route->gw_addr;
+        return 0;
+}
+
+int sd_dhcp_route_get_option(sd_dhcp_route *route) {
+        assert_return(route, -EINVAL);
+
+        return route->option;
+}
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
new file mode 100644
index 0000000..dfced72
--- /dev/null
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -0,0 +1,1222 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <net/if_arp.h>
+#include <sys/ioctl.h>
+
+#include "sd-dhcp-server.h"
+#include "sd-id128.h"
+
+#include "alloc-util.h"
+#include "dhcp-internal.h"
+#include "dhcp-server-internal.h"
+#include "fd-util.h"
+#include "in-addr-util.h"
+#include "io-util.h"
+#include "siphash24.h"
+#include "string-util.h"
+#include "unaligned.h"
+
+#define DHCP_DEFAULT_LEASE_TIME_USEC USEC_PER_HOUR
+#define DHCP_MAX_LEASE_TIME_USEC (USEC_PER_HOUR*12)
+
+static DHCPLease *dhcp_lease_free(DHCPLease *lease) {
+        if (!lease)
+                return NULL;
+
+        free(lease->client_id.data);
+        return mfree(lease);
+}
+
+/* configures the server's address and subnet, and optionally the pool's size and offset into the subnet
+ * the whole pool must fit into the subnet, and may not contain the first (any) nor last (broadcast) address
+ * moreover, the server's own address may be in the pool, and is in that case reserved in order not to
+ * accidentally hand it out */
+int sd_dhcp_server_configure_pool(
+                sd_dhcp_server *server,
+                const struct in_addr *address,
+                unsigned char prefixlen,
+                uint32_t offset,
+                uint32_t size) {
+
+        struct in_addr netmask_addr;
+        be32_t netmask;
+        uint32_t server_off, broadcast_off, size_max;
+
+        assert_return(server, -EINVAL);
+        assert_return(address, -EINVAL);
+        assert_return(address->s_addr != INADDR_ANY, -EINVAL);
+        assert_return(prefixlen <= 32, -ERANGE);
+
+        assert_se(in4_addr_prefixlen_to_netmask(&netmask_addr, prefixlen));
+        netmask = netmask_addr.s_addr;
+
+        server_off = be32toh(address->s_addr & ~netmask);
+        broadcast_off = be32toh(~netmask);
+
+        /* the server address cannot be the subnet address */
+        assert_return(server_off != 0, -ERANGE);
+
+        /* nor the broadcast address */
+        assert_return(server_off != broadcast_off, -ERANGE);
+
+        /* 0 offset means we should set a default, we skip the first (subnet) address
+           and take the next one */
+        if (offset == 0)
+                offset = 1;
+
+        size_max = (broadcast_off + 1) /* the number of addresses in the subnet */
+                   - offset /* exclude the addresses before the offset */
+                   - 1; /* exclude the last (broadcast) address */
+
+        /* The pool must contain at least one address */
+        assert_return(size_max >= 1, -ERANGE);
+
+        if (size != 0)
+                assert_return(size <= size_max, -ERANGE);
+        else
+                size = size_max;
+
+        if (server->address != address->s_addr || server->netmask != netmask || server->pool_size != size || server->pool_offset != offset) {
+
+                free(server->bound_leases);
+                server->bound_leases = new0(DHCPLease*, size);
+                if (!server->bound_leases)
+                        return -ENOMEM;
+
+                server->pool_offset = offset;
+                server->pool_size = size;
+
+                server->address = address->s_addr;
+                server->netmask = netmask;
+                server->subnet = address->s_addr & netmask;
+
+                if (server_off >= offset && server_off - offset < size)
+                        server->bound_leases[server_off - offset] = &server->invalid_lease;
+
+                /* Drop any leases associated with the old address range */
+                hashmap_clear(server->leases_by_client_id);
+
+                if (server->callback)
+                        server->callback(server, SD_DHCP_SERVER_EVENT_LEASE_CHANGED, server->callback_userdata);
+        }
+
+        return 0;
+}
+
+int sd_dhcp_server_is_running(sd_dhcp_server *server) {
+        assert_return(server, false);
+
+        return !!server->receive_message;
+}
+
+void client_id_hash_func(const DHCPClientId *id, struct siphash *state) {
+        assert(id);
+        assert(id->length);
+        assert(id->data);
+
+        siphash24_compress(&id->length, sizeof(id->length), state);
+        siphash24_compress(id->data, id->length, state);
+}
+
+int client_id_compare_func(const DHCPClientId *a, const DHCPClientId *b) {
+        int r;
+
+        assert(!a->length || a->data);
+        assert(!b->length || b->data);
+
+        r = CMP(a->length, b->length);
+        if (r != 0)
+                return r;
+
+        return memcmp(a->data, b->data, a->length);
+}
+
+DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(dhcp_lease_hash_ops, DHCPClientId, client_id_hash_func, client_id_compare_func,
+                                              DHCPLease, dhcp_lease_free);
+
+static sd_dhcp_server *dhcp_server_free(sd_dhcp_server *server) {
+        assert(server);
+
+        log_dhcp_server(server, "UNREF");
+
+        sd_dhcp_server_stop(server);
+
+        sd_event_unref(server->event);
+
+        free(server->timezone);
+
+        for (sd_dhcp_lease_server_type i = 0; i < _SD_DHCP_LEASE_SERVER_TYPE_MAX; i++)
+                free(server->servers[i].addr);
+
+        hashmap_free(server->leases_by_client_id);
+
+        ordered_hashmap_free(server->extra_options);
+        ordered_hashmap_free(server->vendor_options);
+
+        free(server->bound_leases);
+        return mfree(server);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_server, sd_dhcp_server, dhcp_server_free);
+
+int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) {
+        _cleanup_(sd_dhcp_server_unrefp) sd_dhcp_server *server = NULL;
+
+        assert_return(ret, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+
+        server = new0(sd_dhcp_server, 1);
+        if (!server)
+                return -ENOMEM;
+
+        server->n_ref = 1;
+        server->fd_raw = -1;
+        server->fd = -1;
+        server->address = htobe32(INADDR_ANY);
+        server->netmask = htobe32(INADDR_ANY);
+        server->ifindex = ifindex;
+
+        server->leases_by_client_id = hashmap_new(&dhcp_lease_hash_ops);
+        if (!server->leases_by_client_id)
+                return -ENOMEM;
+
+        server->default_lease_time = DIV_ROUND_UP(DHCP_DEFAULT_LEASE_TIME_USEC, USEC_PER_SEC);
+        server->max_lease_time = DIV_ROUND_UP(DHCP_MAX_LEASE_TIME_USEC, USEC_PER_SEC);
+
+        *ret = TAKE_PTR(server);
+
+        return 0;
+}
+
+int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(server, -EINVAL);
+        assert_return(!server->event, -EBUSY);
+
+        if (event)
+                server->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&server->event);
+                if (r < 0)
+                        return r;
+        }
+
+        server->event_priority = priority;
+
+        return 0;
+}
+
+int sd_dhcp_server_detach_event(sd_dhcp_server *server) {
+        assert_return(server, -EINVAL);
+
+        server->event = sd_event_unref(server->event);
+
+        return 0;
+}
+
+sd_event *sd_dhcp_server_get_event(sd_dhcp_server *server) {
+        assert_return(server, NULL);
+
+        return server->event;
+}
+
+int sd_dhcp_server_stop(sd_dhcp_server *server) {
+        if (!server)
+                return 0;
+
+        server->receive_message =
+                sd_event_source_unref(server->receive_message);
+
+        server->fd_raw = safe_close(server->fd_raw);
+        server->fd = safe_close(server->fd);
+
+        log_dhcp_server(server, "STOPPED");
+
+        return 0;
+}
+
+static int dhcp_server_send_unicast_raw(sd_dhcp_server *server,
+                                        DHCPPacket *packet, size_t len) {
+        union sockaddr_union link = {
+                .ll.sll_family = AF_PACKET,
+                .ll.sll_protocol = htobe16(ETH_P_IP),
+                .ll.sll_ifindex = server->ifindex,
+                .ll.sll_halen = ETH_ALEN,
+        };
+
+        assert(server);
+        assert(server->ifindex > 0);
+        assert(server->address);
+        assert(packet);
+        assert(len > sizeof(DHCPPacket));
+
+        memcpy(&link.ll.sll_addr, &packet->dhcp.chaddr, ETH_ALEN);
+
+        dhcp_packet_append_ip_headers(packet, server->address, DHCP_PORT_SERVER,
+                                      packet->dhcp.yiaddr,
+                                      DHCP_PORT_CLIENT, len, -1);
+
+        return dhcp_network_send_raw_socket(server->fd_raw, &link, packet, len);
+}
+
+static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination,
+                                uint16_t destination_port,
+                                DHCPMessage *message, size_t len) {
+        union sockaddr_union dest = {
+                .in.sin_family = AF_INET,
+                .in.sin_port = htobe16(destination_port),
+                .in.sin_addr.s_addr = destination,
+        };
+        struct iovec iov = {
+                .iov_base = message,
+                .iov_len = len,
+        };
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
+        struct msghdr msg = {
+                .msg_name = &dest,
+                .msg_namelen = sizeof(dest.in),
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+        };
+        struct cmsghdr *cmsg;
+        struct in_pktinfo *pktinfo;
+
+        assert(server);
+        assert(server->fd >= 0);
+        assert(message);
+        assert(len > sizeof(DHCPMessage));
+
+        cmsg = CMSG_FIRSTHDR(&msg);
+        assert(cmsg);
+
+        cmsg->cmsg_level = IPPROTO_IP;
+        cmsg->cmsg_type = IP_PKTINFO;
+        cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
+
+        /* we attach source interface and address info to the message
+           rather than binding the socket. This will be mostly useful
+           when we gain support for arbitrary number of server addresses
+         */
+        pktinfo = (struct in_pktinfo*) CMSG_DATA(cmsg);
+        assert(pktinfo);
+
+        pktinfo->ipi_ifindex = server->ifindex;
+        pktinfo->ipi_spec_dst.s_addr = server->address;
+
+        if (sendmsg(server->fd, &msg, 0) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static bool requested_broadcast(DHCPRequest *req) {
+        assert(req);
+
+        return req->message->flags & htobe16(0x8000);
+}
+
+int dhcp_server_send_packet(sd_dhcp_server *server,
+                            DHCPRequest *req, DHCPPacket *packet,
+                            int type, size_t optoffset) {
+        be32_t destination = INADDR_ANY;
+        uint16_t destination_port = DHCP_PORT_CLIENT;
+        int r;
+
+        assert(server);
+        assert(req);
+        assert(req->max_optlen);
+        assert(optoffset <= req->max_optlen);
+        assert(packet);
+
+        r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0,
+                               SD_DHCP_OPTION_SERVER_IDENTIFIER,
+                               4, &server->address);
+        if (r < 0)
+                return r;
+
+        r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0,
+                               SD_DHCP_OPTION_END, 0, NULL);
+        if (r < 0)
+                return r;
+
+        /* RFC 2131 Section 4.1
+
+           If the ’giaddr’ field in a DHCP message from a client is non-zero,
+           the server sends any return messages to the ’DHCP server’ port on the
+           BOOTP relay agent whose address appears in ’giaddr’. If the ’giaddr’
+           field is zero and the ’ciaddr’ field is nonzero, then the server
+           unicasts DHCPOFFER and DHCPACK messages to the address in ’ciaddr’.
+           If ’giaddr’ is zero and ’ciaddr’ is zero, and the broadcast bit is
+           set, then the server broadcasts DHCPOFFER and DHCPACK messages to
+           0xffffffff. If the broadcast bit is not set and ’giaddr’ is zero and
+           ’ciaddr’ is zero, then the server unicasts DHCPOFFER and DHCPACK
+           messages to the client’s hardware address and ’yiaddr’ address. In
+           all cases, when ’giaddr’ is zero, the server broadcasts any DHCPNAK
+           messages to 0xffffffff.
+
+           Section 4.3.2
+
+           If ’giaddr’ is set in the DHCPREQUEST message, the client is on a
+           different subnet. The server MUST set the broadcast bit in the
+           DHCPNAK, so that the relay agent will broadcast the DHCPNAK to the
+           client, because the client may not have a correct network address
+           or subnet mask, and the client may not be answering ARP requests.
+         */
+        if (req->message->giaddr) {
+                destination = req->message->giaddr;
+                destination_port = DHCP_PORT_SERVER;
+                if (type == DHCP_NAK)
+                        packet->dhcp.flags = htobe16(0x8000);
+        } else if (req->message->ciaddr && type != DHCP_NAK)
+                destination = req->message->ciaddr;
+
+        if (destination != INADDR_ANY)
+                return dhcp_server_send_udp(server, destination,
+                                            destination_port, &packet->dhcp,
+                                            sizeof(DHCPMessage) + optoffset);
+        else if (requested_broadcast(req) || type == DHCP_NAK)
+                return dhcp_server_send_udp(server, INADDR_BROADCAST,
+                                            destination_port, &packet->dhcp,
+                                            sizeof(DHCPMessage) + optoffset);
+        else
+                /* we cannot send UDP packet to specific MAC address when the
+                   address is not yet configured, so must fall back to raw
+                   packets */
+                return dhcp_server_send_unicast_raw(server, packet,
+                                                    sizeof(DHCPPacket) + optoffset);
+}
+
+static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret,
+                               uint8_t type, size_t *_optoffset,
+                               DHCPRequest *req) {
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        size_t optoffset = 0;
+        int r;
+
+        assert(server);
+        assert(ret);
+        assert(_optoffset);
+        assert(IN_SET(type, DHCP_OFFER, DHCP_ACK, DHCP_NAK));
+
+        packet = malloc0(sizeof(DHCPPacket) + req->max_optlen);
+        if (!packet)
+                return -ENOMEM;
+
+        r = dhcp_message_init(&packet->dhcp, BOOTREPLY,
+                              be32toh(req->message->xid), type, ARPHRD_ETHER,
+                              req->max_optlen, &optoffset);
+        if (r < 0)
+                return r;
+
+        packet->dhcp.flags = req->message->flags;
+        packet->dhcp.giaddr = req->message->giaddr;
+        memcpy(&packet->dhcp.chaddr, &req->message->chaddr, ETH_ALEN);
+
+        *_optoffset = optoffset;
+        *ret = TAKE_PTR(packet);
+
+        return 0;
+}
+
+static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req,
+                             be32_t address) {
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        size_t offset;
+        be32_t lease_time;
+        int r;
+
+        r = server_message_init(server, &packet, DHCP_OFFER, &offset, req);
+        if (r < 0)
+                return r;
+
+        packet->dhcp.yiaddr = address;
+
+        lease_time = htobe32(req->lifetime);
+        r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                               SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4,
+                               &lease_time);
+        if (r < 0)
+                return r;
+
+        r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                               SD_DHCP_OPTION_SUBNET_MASK, 4, &server->netmask);
+        if (r < 0)
+                return r;
+
+        if (server->emit_router) {
+                r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                                       SD_DHCP_OPTION_ROUTER, 4, &server->address);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp_server_send_packet(server, req, packet, DHCP_OFFER, offset);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int server_send_ack(
+                sd_dhcp_server *server,
+                DHCPRequest *req,
+                be32_t address) {
+
+        static const uint8_t option_map[_SD_DHCP_LEASE_SERVER_TYPE_MAX] = {
+                [SD_DHCP_LEASE_DNS] = SD_DHCP_OPTION_DOMAIN_NAME_SERVER,
+                [SD_DHCP_LEASE_NTP] = SD_DHCP_OPTION_NTP_SERVER,
+                [SD_DHCP_LEASE_SIP] = SD_DHCP_OPTION_SIP_SERVER,
+                [SD_DHCP_LEASE_POP3] = SD_DHCP_OPTION_POP3_SERVER,
+                [SD_DHCP_LEASE_SMTP] = SD_DHCP_OPTION_SMTP_SERVER,
+                [SD_DHCP_LEASE_LPR] = SD_DHCP_OPTION_LPR_SERVER,
+        };
+
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        be32_t lease_time;
+        sd_dhcp_option *j;
+        size_t offset;
+        int r;
+
+        r = server_message_init(server, &packet, DHCP_ACK, &offset, req);
+        if (r < 0)
+                return r;
+
+        packet->dhcp.yiaddr = address;
+
+        lease_time = htobe32(req->lifetime);
+        r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                               SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4,
+                               &lease_time);
+        if (r < 0)
+                return r;
+
+        r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                               SD_DHCP_OPTION_SUBNET_MASK, 4, &server->netmask);
+        if (r < 0)
+                return r;
+
+        if (server->emit_router) {
+                r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                                       SD_DHCP_OPTION_ROUTER, 4, &server->address);
+                if (r < 0)
+                        return r;
+        }
+
+        for (sd_dhcp_lease_server_type k = 0; k < _SD_DHCP_LEASE_SERVER_TYPE_MAX; k++) {
+
+                if (server->servers[k].size <= 0)
+                        continue;
+
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                option_map[k],
+                                sizeof(struct in_addr) * server->servers[k].size, server->servers[k].addr);
+                if (r < 0)
+                        return r;
+        }
+
+
+        if (server->timezone) {
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                SD_DHCP_OPTION_NEW_TZDB_TIMEZONE,
+                                strlen(server->timezone), server->timezone);
+                if (r < 0)
+                        return r;
+        }
+
+        ORDERED_HASHMAP_FOREACH(j, server->extra_options) {
+                r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+                                       j->option, j->length, j->data);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!ordered_hashmap_isempty(server->vendor_options)) {
+                r = dhcp_option_append(
+                                &packet->dhcp, req->max_optlen, &offset, 0,
+                                SD_DHCP_OPTION_VENDOR_SPECIFIC,
+                                ordered_hashmap_size(server->vendor_options), server->vendor_options);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int server_send_nak(sd_dhcp_server *server, DHCPRequest *req) {
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        size_t offset;
+        int r;
+
+        r = server_message_init(server, &packet, DHCP_NAK, &offset, req);
+        if (r < 0)
+                return r;
+
+        return dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset);
+}
+
+static int server_send_forcerenew(sd_dhcp_server *server, be32_t address,
+                                  be32_t gateway, const uint8_t chaddr[]) {
+        _cleanup_free_ DHCPPacket *packet = NULL;
+        size_t optoffset = 0;
+        int r;
+
+        assert(server);
+        assert(address != INADDR_ANY);
+        assert(chaddr);
+
+        packet = malloc0(sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE);
+        if (!packet)
+                return -ENOMEM;
+
+        r = dhcp_message_init(&packet->dhcp, BOOTREPLY, 0,
+                              DHCP_FORCERENEW, ARPHRD_ETHER,
+                              DHCP_MIN_OPTIONS_SIZE, &optoffset);
+        if (r < 0)
+                return r;
+
+        r = dhcp_option_append(&packet->dhcp, DHCP_MIN_OPTIONS_SIZE,
+                               &optoffset, 0, SD_DHCP_OPTION_END, 0, NULL);
+        if (r < 0)
+                return r;
+
+        memcpy(&packet->dhcp.chaddr, chaddr, ETH_ALEN);
+
+        r = dhcp_server_send_udp(server, address, DHCP_PORT_CLIENT,
+                                 &packet->dhcp,
+                                 sizeof(DHCPMessage) + optoffset);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int parse_request(uint8_t code, uint8_t len, const void *option, void *userdata) {
+        DHCPRequest *req = userdata;
+
+        assert(req);
+
+        switch(code) {
+        case SD_DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
+                if (len == 4)
+                        req->lifetime = unaligned_read_be32(option);
+
+                break;
+        case SD_DHCP_OPTION_REQUESTED_IP_ADDRESS:
+                if (len == 4)
+                        memcpy(&req->requested_ip, option, sizeof(be32_t));
+
+                break;
+        case SD_DHCP_OPTION_SERVER_IDENTIFIER:
+                if (len == 4)
+                        memcpy(&req->server_id, option, sizeof(be32_t));
+
+                break;
+        case SD_DHCP_OPTION_CLIENT_IDENTIFIER:
+                if (len >= 2) {
+                        uint8_t *data;
+
+                        data = memdup(option, len);
+                        if (!data)
+                                return -ENOMEM;
+
+                        free(req->client_id.data);
+                        req->client_id.data = data;
+                        req->client_id.length = len;
+                }
+
+                break;
+        case SD_DHCP_OPTION_MAXIMUM_MESSAGE_SIZE:
+
+                if (len == 2 && unaligned_read_be16(option) >= sizeof(DHCPPacket))
+                        req->max_optlen = unaligned_read_be16(option) - sizeof(DHCPPacket);
+
+                break;
+        }
+
+        return 0;
+}
+
+static void dhcp_request_free(DHCPRequest *req) {
+        if (!req)
+                return;
+
+        free(req->client_id.data);
+        free(req);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPRequest*, dhcp_request_free);
+
+static int ensure_sane_request(sd_dhcp_server *server, DHCPRequest *req, DHCPMessage *message) {
+        assert(req);
+        assert(message);
+
+        req->message = message;
+
+        /* set client id based on MAC address if client did not send an explicit
+           one */
+        if (!req->client_id.data) {
+                void *data;
+
+                data = malloc0(ETH_ALEN + 1);
+                if (!data)
+                        return -ENOMEM;
+
+                ((uint8_t*) data)[0] = 0x01;
+                memcpy((uint8_t*) data + 1, &message->chaddr, ETH_ALEN);
+
+                req->client_id.length = ETH_ALEN + 1;
+                req->client_id.data = data;
+        }
+
+        if (req->max_optlen < DHCP_MIN_OPTIONS_SIZE)
+                req->max_optlen = DHCP_MIN_OPTIONS_SIZE;
+
+        if (req->lifetime <= 0)
+                req->lifetime = MAX(1ULL, server->default_lease_time);
+
+        if (server->max_lease_time > 0 && req->lifetime > server->max_lease_time)
+                req->lifetime = server->max_lease_time;
+
+        return 0;
+}
+
+static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) {
+        assert(server);
+
+        if (!server->pool_size)
+                return -EINVAL;
+
+        if (be32toh(requested_ip) < (be32toh(server->subnet) | server->pool_offset) ||
+            be32toh(requested_ip) >= (be32toh(server->subnet) | (server->pool_offset + server->pool_size)))
+                return -ERANGE;
+
+        return be32toh(requested_ip & ~server->netmask) - server->pool_offset;
+}
+
+#define HASH_KEY SD_ID128_MAKE(0d,1d,fe,bd,f1,24,bd,b3,47,f1,dd,6e,73,21,93,30)
+
+int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
+                               size_t length) {
+        _cleanup_(dhcp_request_freep) DHCPRequest *req = NULL;
+        _cleanup_free_ char *error_message = NULL;
+        DHCPLease *existing_lease;
+        int type, r;
+
+        assert(server);
+        assert(message);
+
+        if (message->op != BOOTREQUEST ||
+            message->htype != ARPHRD_ETHER ||
+            message->hlen != ETHER_ADDR_LEN)
+                return 0;
+
+        req = new0(DHCPRequest, 1);
+        if (!req)
+                return -ENOMEM;
+
+        type = dhcp_option_parse(message, length, parse_request, req, &error_message);
+        if (type < 0)
+                return 0;
+
+        r = ensure_sane_request(server, req, message);
+        if (r < 0)
+                /* this only fails on critical errors */
+                return r;
+
+        existing_lease = hashmap_get(server->leases_by_client_id,
+                                     &req->client_id);
+
+        switch(type) {
+
+        case DHCP_DISCOVER: {
+                be32_t address = INADDR_ANY;
+                unsigned i;
+
+                log_dhcp_server(server, "DISCOVER (0x%x)",
+                                be32toh(req->message->xid));
+
+                if (!server->pool_size)
+                        /* no pool allocated */
+                        return 0;
+
+                /* for now pick a random free address from the pool */
+                if (existing_lease)
+                        address = existing_lease->address;
+                else {
+                        struct siphash state;
+                        uint64_t hash;
+                        uint32_t next_offer;
+
+                        /* even with no persistence of leases, we try to offer the same client
+                           the same IP address. we do this by using the hash of the client id
+                           as the offset into the pool of leases when finding the next free one */
+
+                        siphash24_init(&state, HASH_KEY.bytes);
+                        client_id_hash_func(&req->client_id, &state);
+                        hash = htole64(siphash24_finalize(&state));
+                        next_offer = hash % server->pool_size;
+
+                        for (i = 0; i < server->pool_size; i++) {
+                                if (!server->bound_leases[next_offer]) {
+                                        address = server->subnet | htobe32(server->pool_offset + next_offer);
+                                        break;
+                                }
+
+                                next_offer = (next_offer + 1) % server->pool_size;
+                        }
+                }
+
+                if (address == INADDR_ANY)
+                        /* no free addresses left */
+                        return 0;
+
+                r = server_send_offer(server, req, address);
+                if (r < 0)
+                        /* this only fails on critical errors */
+                        return log_dhcp_server_errno(server, r, "Could not send offer: %m");
+
+                log_dhcp_server(server, "OFFER (0x%x)", be32toh(req->message->xid));
+                return DHCP_OFFER;
+        }
+        case DHCP_DECLINE:
+                log_dhcp_server(server, "DECLINE (0x%x): %s", be32toh(req->message->xid), strna(error_message));
+
+                /* TODO: make sure we don't offer this address again */
+
+                return 1;
+
+        case DHCP_REQUEST: {
+                be32_t address;
+                bool init_reboot = false;
+                int pool_offset;
+
+                /* see RFC 2131, section 4.3.2 */
+
+                if (req->server_id) {
+                        log_dhcp_server(server, "REQUEST (selecting) (0x%x)",
+                                        be32toh(req->message->xid));
+
+                        /* SELECTING */
+                        if (req->server_id != server->address)
+                                /* client did not pick us */
+                                return 0;
+
+                        if (req->message->ciaddr)
+                                /* this MUST be zero */
+                                return 0;
+
+                        if (!req->requested_ip)
+                                /* this must be filled in with the yiaddr
+                                   from the chosen OFFER */
+                                return 0;
+
+                        address = req->requested_ip;
+                } else if (req->requested_ip) {
+                        log_dhcp_server(server, "REQUEST (init-reboot) (0x%x)",
+                                        be32toh(req->message->xid));
+
+                        /* INIT-REBOOT */
+                        if (req->message->ciaddr)
+                                /* this MUST be zero */
+                                return 0;
+
+                        /* TODO: check more carefully if IP is correct */
+                        address = req->requested_ip;
+                        init_reboot = true;
+                } else {
+                        log_dhcp_server(server, "REQUEST (rebinding/renewing) (0x%x)",
+                                        be32toh(req->message->xid));
+
+                        /* REBINDING / RENEWING */
+                        if (!req->message->ciaddr)
+                                /* this MUST be filled in with clients IP address */
+                                return 0;
+
+                        address = req->message->ciaddr;
+                }
+
+                pool_offset = get_pool_offset(server, address);
+
+                /* verify that the requested address is from the pool, and either
+                   owned by the current client or free */
+                if (pool_offset >= 0 &&
+                    server->bound_leases[pool_offset] == existing_lease) {
+                        DHCPLease *lease;
+                        usec_t time_now = 0;
+
+                        if (!existing_lease) {
+                                lease = new0(DHCPLease, 1);
+                                if (!lease)
+                                        return -ENOMEM;
+                                lease->address = address;
+                                lease->client_id.data = memdup(req->client_id.data,
+                                                               req->client_id.length);
+                                if (!lease->client_id.data) {
+                                        free(lease);
+                                        return -ENOMEM;
+                                }
+                                lease->client_id.length = req->client_id.length;
+                                memcpy(&lease->chaddr, &req->message->chaddr,
+                                       ETH_ALEN);
+                                lease->gateway = req->message->giaddr;
+                        } else
+                                lease = existing_lease;
+
+                        r = sd_event_now(server->event,
+                                         clock_boottime_or_monotonic(),
+                                         &time_now);
+                        if (r < 0) {
+                                if (!existing_lease)
+                                        dhcp_lease_free(lease);
+                                return r;
+                        }
+
+                        lease->expiration = req->lifetime * USEC_PER_SEC + time_now;
+
+                        r = server_send_ack(server, req, address);
+                        if (r < 0) {
+                                /* this only fails on critical errors */
+                                log_dhcp_server_errno(server, r, "Could not send ack: %m");
+
+                                if (!existing_lease)
+                                        dhcp_lease_free(lease);
+
+                                return r;
+                        } else {
+                                log_dhcp_server(server, "ACK (0x%x)",
+                                                be32toh(req->message->xid));
+
+                                server->bound_leases[pool_offset] = lease;
+                                hashmap_put(server->leases_by_client_id,
+                                            &lease->client_id, lease);
+
+                                if (server->callback)
+                                        server->callback(server, SD_DHCP_SERVER_EVENT_LEASE_CHANGED, server->callback_userdata);
+
+                                return DHCP_ACK;
+                        }
+
+                } else if (init_reboot) {
+                        r = server_send_nak(server, req);
+                        if (r < 0)
+                                /* this only fails on critical errors */
+                                return log_dhcp_server_errno(server, r, "Could not send nak: %m");
+
+                        log_dhcp_server(server, "NAK (0x%x)", be32toh(req->message->xid));
+                        return DHCP_NAK;
+                }
+
+                break;
+        }
+
+        case DHCP_RELEASE: {
+                int pool_offset;
+
+                log_dhcp_server(server, "RELEASE (0x%x)",
+                                be32toh(req->message->xid));
+
+                if (!existing_lease)
+                        return 0;
+
+                if (existing_lease->address != req->message->ciaddr)
+                        return 0;
+
+                pool_offset = get_pool_offset(server, req->message->ciaddr);
+                if (pool_offset < 0)
+                        return 0;
+
+                if (server->bound_leases[pool_offset] == existing_lease) {
+                        server->bound_leases[pool_offset] = NULL;
+                        hashmap_remove(server->leases_by_client_id, existing_lease);
+                        dhcp_lease_free(existing_lease);
+
+                        if (server->callback)
+                                server->callback(server, SD_DHCP_SERVER_EVENT_LEASE_CHANGED, server->callback_userdata);
+                }
+
+                return 0;
+        }}
+
+        return 0;
+}
+
+static int server_receive_message(sd_event_source *s, int fd,
+                                  uint32_t revents, void *userdata) {
+        _cleanup_free_ DHCPMessage *message = NULL;
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control;
+        sd_dhcp_server *server = userdata;
+        struct iovec iov = {};
+        struct msghdr msg = {
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+        };
+        struct cmsghdr *cmsg;
+        ssize_t buflen, len;
+        int r;
+
+        assert(server);
+
+        buflen = next_datagram_size_fd(fd);
+        if (buflen < 0)
+                return buflen;
+
+        message = malloc(buflen);
+        if (!message)
+                return -ENOMEM;
+
+        iov = IOVEC_MAKE(message, buflen);
+
+        len = recvmsg_safe(fd, &msg, 0);
+        if (IN_SET(len, -EAGAIN, -EINTR))
+                return 0;
+        if (len < 0)
+                return len;
+        if ((size_t) len < sizeof(DHCPMessage))
+                return 0;
+
+        CMSG_FOREACH(cmsg, &msg) {
+                if (cmsg->cmsg_level == IPPROTO_IP &&
+                    cmsg->cmsg_type == IP_PKTINFO &&
+                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) {
+                        struct in_pktinfo *info = (struct in_pktinfo*)CMSG_DATA(cmsg);
+
+                        /* TODO figure out if this can be done as a filter on
+                         * the socket, like for IPv6 */
+                        if (server->ifindex != info->ipi_ifindex)
+                                return 0;
+
+                        break;
+                }
+        }
+
+        r = dhcp_server_handle_message(server, message, (size_t) len);
+        if (r < 0)
+                log_dhcp_server_errno(server, r, "Couldn't process incoming message: %m");
+
+        return 0;
+}
+
+int sd_dhcp_server_start(sd_dhcp_server *server) {
+        int r;
+
+        assert_return(server, -EINVAL);
+        assert_return(server->event, -EINVAL);
+        assert_return(!server->receive_message, -EBUSY);
+        assert_return(server->fd_raw < 0, -EBUSY);
+        assert_return(server->fd < 0, -EBUSY);
+        assert_return(server->address != htobe32(INADDR_ANY), -EUNATCH);
+
+        r = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (r < 0) {
+                r = -errno;
+                sd_dhcp_server_stop(server);
+                return r;
+        }
+        server->fd_raw = r;
+
+        r = dhcp_network_bind_udp_socket(server->ifindex, INADDR_ANY, DHCP_PORT_SERVER, -1);
+        if (r < 0) {
+                sd_dhcp_server_stop(server);
+                return r;
+        }
+        server->fd = r;
+
+        r = sd_event_add_io(server->event, &server->receive_message,
+                            server->fd, EPOLLIN,
+                            server_receive_message, server);
+        if (r < 0) {
+                sd_dhcp_server_stop(server);
+                return r;
+        }
+
+        r = sd_event_source_set_priority(server->receive_message,
+                                         server->event_priority);
+        if (r < 0) {
+                sd_dhcp_server_stop(server);
+                return r;
+        }
+
+        log_dhcp_server(server, "STARTED");
+
+        return 0;
+}
+
+int sd_dhcp_server_forcerenew(sd_dhcp_server *server) {
+        unsigned i;
+        int r = 0;
+
+        assert_return(server, -EINVAL);
+        assert(server->bound_leases);
+
+        for (i = 0; i < server->pool_size; i++) {
+                DHCPLease *lease = server->bound_leases[i];
+
+                if (!lease || lease == &server->invalid_lease)
+                        continue;
+
+                r = server_send_forcerenew(server, lease->address,
+                                           lease->gateway,
+                                           lease->chaddr);
+                if (r < 0)
+                        return r;
+
+                log_dhcp_server(server, "FORCERENEW");
+        }
+
+        return r;
+}
+
+int sd_dhcp_server_set_timezone(sd_dhcp_server *server, const char *tz) {
+        int r;
+
+        assert_return(server, -EINVAL);
+        assert_return(timezone_is_valid(tz, LOG_DEBUG), -EINVAL);
+
+        if (streq_ptr(tz, server->timezone))
+                return 0;
+
+        r = free_and_strdup(&server->timezone, tz);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int sd_dhcp_server_set_max_lease_time(sd_dhcp_server *server, uint32_t t) {
+        assert_return(server, -EINVAL);
+
+        if (t == server->max_lease_time)
+                return 0;
+
+        server->max_lease_time = t;
+        return 1;
+}
+
+int sd_dhcp_server_set_default_lease_time(sd_dhcp_server *server, uint32_t t) {
+        assert_return(server, -EINVAL);
+
+        if (t == server->default_lease_time)
+                return 0;
+
+        server->default_lease_time = t;
+        return 1;
+}
+
+int sd_dhcp_server_set_servers(
+                sd_dhcp_server *server,
+                sd_dhcp_lease_server_type what,
+                const struct in_addr addresses[],
+                size_t n_addresses) {
+
+        struct in_addr *c = NULL;
+
+        assert_return(server, -EINVAL);
+        assert_return(addresses || n_addresses == 0, -EINVAL);
+        assert_return(what >= 0, -EINVAL);
+        assert_return(what < _SD_DHCP_LEASE_SERVER_TYPE_MAX, -EINVAL);
+
+        if (server->servers[what].size == n_addresses &&
+            memcmp(server->servers[what].addr, addresses, sizeof(struct in_addr) * n_addresses) == 0)
+                return 0;
+
+        if (n_addresses > 0) {
+                c = newdup(struct in_addr, addresses, n_addresses);
+                if (!c)
+                        return -ENOMEM;
+        }
+
+        free(server->servers[what].addr);
+        server->servers[what].addr = c;
+        server->servers[what].size = n_addresses;
+        return 1;
+}
+
+int sd_dhcp_server_set_dns(sd_dhcp_server *server, const struct in_addr dns[], size_t n) {
+        return sd_dhcp_server_set_servers(server, SD_DHCP_LEASE_DNS, dns, n);
+}
+int sd_dhcp_server_set_ntp(sd_dhcp_server *server, const struct in_addr ntp[], size_t n) {
+        return sd_dhcp_server_set_servers(server, SD_DHCP_LEASE_NTP, ntp, n);
+}
+int sd_dhcp_server_set_sip(sd_dhcp_server *server, const struct in_addr sip[], size_t n) {
+        return sd_dhcp_server_set_servers(server, SD_DHCP_LEASE_SIP, sip, n);
+}
+int sd_dhcp_server_set_pop3(sd_dhcp_server *server, const struct in_addr pop3[], size_t n) {
+        return sd_dhcp_server_set_servers(server, SD_DHCP_LEASE_POP3, pop3, n);
+}
+int sd_dhcp_server_set_smtp(sd_dhcp_server *server, const struct in_addr smtp[], size_t n) {
+        return sd_dhcp_server_set_servers(server, SD_DHCP_LEASE_SMTP, smtp, n);
+}
+int sd_dhcp_server_set_lpr(sd_dhcp_server *server, const struct in_addr lpr[], size_t n) {
+        return sd_dhcp_server_set_servers(server, SD_DHCP_LEASE_LPR, lpr, n);
+}
+
+int sd_dhcp_server_set_emit_router(sd_dhcp_server *server, int enabled) {
+        assert_return(server, -EINVAL);
+
+        if (enabled == server->emit_router)
+                return 0;
+
+        server->emit_router = enabled;
+
+        return 1;
+}
+
+int sd_dhcp_server_add_option(sd_dhcp_server *server, sd_dhcp_option *v) {
+        int r;
+
+        assert_return(server, -EINVAL);
+        assert_return(v, -EINVAL);
+
+        r = ordered_hashmap_ensure_allocated(&server->extra_options, &dhcp_option_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = ordered_hashmap_put(server->extra_options, UINT_TO_PTR(v->option), v);
+        if (r < 0)
+                return r;
+
+        sd_dhcp_option_ref(v);
+        return 0;
+}
+
+int sd_dhcp_server_add_vendor_option(sd_dhcp_server *server, sd_dhcp_option *v) {
+        int r;
+
+        assert_return(server, -EINVAL);
+        assert_return(v, -EINVAL);
+
+        r = ordered_hashmap_ensure_allocated(&server->vendor_options, &dhcp_option_hash_ops);
+        if (r < 0)
+                return -ENOMEM;
+
+        r = ordered_hashmap_put(server->vendor_options, v, v);
+        if (r < 0)
+                return r;
+
+        sd_dhcp_option_ref(v);
+
+        return 1;
+}
+
+int sd_dhcp_server_set_callback(sd_dhcp_server *server, sd_dhcp_server_callback_t cb, void *userdata) {
+        assert_return(server, -EINVAL);
+
+        server->callback = cb;
+        server->callback_userdata = userdata;
+
+        return 0;
+}
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
new file mode 100644
index 0000000..d502051
--- /dev/null
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -0,0 +1,1848 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014-2015 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <linux/if_arp.h>
+#include <linux/if_infiniband.h>
+
+#include "sd-dhcp6-client.h"
+
+#include "alloc-util.h"
+#include "dhcp-identifier.h"
+#include "dhcp6-internal.h"
+#include "dhcp6-lease-internal.h"
+#include "dhcp6-protocol.h"
+#include "dns-domain.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "hexdecoct.h"
+#include "hostname-util.h"
+#include "in-addr-util.h"
+#include "network-internal.h"
+#include "random-util.h"
+#include "socket-util.h"
+#include "string-table.h"
+#include "util.h"
+#include "web-util.h"
+
+#define MAX_MAC_ADDR_LEN INFINIBAND_ALEN
+
+#define IRT_DEFAULT (1 * USEC_PER_DAY)
+#define IRT_MINIMUM (600 * USEC_PER_SEC)
+
+/* what to request from the server, addresses (IA_NA) and/or prefixes (IA_PD) */
+enum {
+        DHCP6_REQUEST_IA_NA                     = 1,
+        DHCP6_REQUEST_IA_TA                     = 2, /* currently not used */
+        DHCP6_REQUEST_IA_PD                     = 4,
+};
+
+struct sd_dhcp6_client {
+        unsigned n_ref;
+
+        enum DHCP6State state;
+        sd_event *event;
+        int event_priority;
+        int ifindex;
+        DHCP6Address hint_pd_prefix;
+        struct in6_addr local_address;
+        uint8_t mac_addr[MAX_MAC_ADDR_LEN];
+        size_t mac_addr_len;
+        uint16_t arp_type;
+        DHCP6IA ia_na;
+        DHCP6IA ia_pd;
+        sd_event_source *timeout_t1;
+        sd_event_source *timeout_t2;
+        unsigned request;
+        be32_t transaction_id;
+        usec_t transaction_start;
+        struct sd_dhcp6_lease *lease;
+        int fd;
+        bool information_request;
+        bool iaid_set;
+        be16_t *req_opts;
+        size_t req_opts_allocated;
+        size_t req_opts_len;
+        char *fqdn;
+        char *mudurl;
+        char **user_class;
+        char **vendor_class;
+        sd_event_source *receive_message;
+        usec_t retransmit_time;
+        uint8_t retransmit_count;
+        sd_event_source *timeout_resend;
+        sd_event_source *timeout_resend_expire;
+        sd_dhcp6_client_callback_t callback;
+        void *userdata;
+        struct duid duid;
+        size_t duid_len;
+        usec_t information_request_time_usec;
+        usec_t information_refresh_time_usec;
+        OrderedHashmap *extra_options;
+        OrderedHashmap *vendor_options;
+};
+
+static const uint16_t default_req_opts[] = {
+        SD_DHCP6_OPTION_DNS_SERVERS,
+        SD_DHCP6_OPTION_DOMAIN_LIST,
+        SD_DHCP6_OPTION_NTP_SERVER,
+        SD_DHCP6_OPTION_SNTP_SERVERS,
+};
+
+const char * dhcp6_message_type_table[_DHCP6_MESSAGE_MAX] = {
+        [DHCP6_SOLICIT] = "SOLICIT",
+        [DHCP6_ADVERTISE] = "ADVERTISE",
+        [DHCP6_REQUEST] = "REQUEST",
+        [DHCP6_CONFIRM] = "CONFIRM",
+        [DHCP6_RENEW] = "RENEW",
+        [DHCP6_REBIND] = "REBIND",
+        [DHCP6_REPLY] = "REPLY",
+        [DHCP6_RELEASE] = "RELEASE",
+        [DHCP6_DECLINE] = "DECLINE",
+        [DHCP6_RECONFIGURE] = "RECONFIGURE",
+        [DHCP6_INFORMATION_REQUEST] = "INFORMATION-REQUEST",
+        [DHCP6_RELAY_FORW] = "RELAY-FORW",
+        [DHCP6_RELAY_REPL] = "RELAY-REPL",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(dhcp6_message_type, int);
+
+const char * dhcp6_message_status_table[_DHCP6_STATUS_MAX] = {
+        [DHCP6_STATUS_SUCCESS]                      = "Success",
+        [DHCP6_STATUS_UNSPEC_FAIL]                  = "Unspecified failure",
+        [DHCP6_STATUS_NO_ADDRS_AVAIL]               = "No addresses available",
+        [DHCP6_STATUS_NO_BINDING]                   = "Binding unavailable",
+        [DHCP6_STATUS_NOT_ON_LINK]                  = "Not on link",
+        [DHCP6_STATUS_USE_MULTICAST]                = "Use multicast",
+        [DHCP6_STATUS_NO_PREFIX_AVAIL]              = "No prefix available",
+        [DHCP6_STATUS_UNKNOWN_QUERY_TYPE]           = "Unknown query type",
+        [DHCP6_STATUS_MALFORMED_QUERY]              = "Malformed query",
+        [DHCP6_STATUS_NOT_CONFIGURED]               = "Not configured",
+        [DHCP6_STATUS_NOT_ALLOWED]                  = "Not allowed",
+        [DHCP6_STATUS_QUERY_TERMINATED]             = "Query terminated",
+        [DHCP6_STATUS_DATA_MISSING]                 = "Data missing",
+        [DHCP6_STATUS_CATCHUP_COMPLETE]             = "Catch up complete",
+        [DHCP6_STATUS_NOT_SUPPORTED]                = "Not supported",
+        [DHCP6_STATUS_TLS_CONNECTION_REFUSED]       = "TLS connection refused",
+        [DHCP6_STATUS_ADDRESS_IN_USE]               = "Address in use",
+        [DHCP6_STATUS_CONFIGURATION_CONFLICT]       = "Configuration conflict",
+        [DHCP6_STATUS_MISSING_BINDING_INFORMATION]  = "Missing binding information",
+        [DHCP6_STATUS_OUTDATED_BINDING_INFORMATION] = "Outdated binding information",
+        [DHCP6_STATUS_SERVER_SHUTTING_DOWN]         = "Server shutting down",
+        [DHCP6_STATUS_DNS_UPDATE_NOT_SUPPORTED]     = "DNS update not supported",
+        [DHCP6_STATUS_EXCESSIVE_TIME_SKEW]          = "Excessive time skew",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(dhcp6_message_status, int);
+
+#define DHCP6_CLIENT_DONT_DESTROY(client) \
+        _cleanup_(sd_dhcp6_client_unrefp) _unused_ sd_dhcp6_client *_dont_destroy_##client = sd_dhcp6_client_ref(client)
+
+static int client_start(sd_dhcp6_client *client, enum DHCP6State state);
+
+int sd_dhcp6_client_set_callback(
+                sd_dhcp6_client *client,
+                sd_dhcp6_client_callback_t cb,
+                void *userdata) {
+
+        assert_return(client, -EINVAL);
+
+        client->callback = cb;
+        client->userdata = userdata;
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_ifindex(sd_dhcp6_client *client, int ifindex) {
+
+        assert_return(client, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        client->ifindex = ifindex;
+        return 0;
+}
+
+int sd_dhcp6_client_set_local_address(
+                sd_dhcp6_client *client,
+                const struct in6_addr *local_address) {
+
+        assert_return(client, -EINVAL);
+        assert_return(local_address, -EINVAL);
+        assert_return(in_addr_is_link_local(AF_INET6, (const union in_addr_union *) local_address) > 0, -EINVAL);
+
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        client->local_address = *local_address;
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_mac(
+                sd_dhcp6_client *client,
+                const uint8_t *addr, size_t addr_len,
+                uint16_t arp_type) {
+
+        assert_return(client, -EINVAL);
+        assert_return(addr, -EINVAL);
+        assert_return(addr_len <= MAX_MAC_ADDR_LEN, -EINVAL);
+
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        if (arp_type == ARPHRD_ETHER)
+                assert_return(addr_len == ETH_ALEN, -EINVAL);
+        else if (arp_type == ARPHRD_INFINIBAND)
+                assert_return(addr_len == INFINIBAND_ALEN, -EINVAL);
+        else {
+                client->arp_type = ARPHRD_NONE;
+                client->mac_addr_len = 0;
+                return 0;
+        }
+
+        if (client->mac_addr_len == addr_len &&
+            memcmp(&client->mac_addr, addr, addr_len) == 0)
+                return 0;
+
+        memcpy(&client->mac_addr, addr, addr_len);
+        client->mac_addr_len = addr_len;
+        client->arp_type = arp_type;
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_prefix_delegation_hint(
+                sd_dhcp6_client *client,
+                uint8_t prefixlen,
+                const struct in6_addr *pd_address) {
+
+        assert_return(client, -EINVAL);
+        assert_return(pd_address, -EINVAL);
+
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        client->hint_pd_prefix.iapdprefix.address = *pd_address;
+        client->hint_pd_prefix.iapdprefix.prefixlen = prefixlen;
+
+        return 0;
+}
+
+int sd_dhcp6_client_add_vendor_option(sd_dhcp6_client *client, sd_dhcp6_option *v) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(v, -EINVAL);
+
+        r = ordered_hashmap_ensure_allocated(&client->vendor_options, &dhcp6_option_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = ordered_hashmap_put(client->vendor_options, v, v);
+        if (r < 0)
+                return r;
+
+        sd_dhcp6_option_ref(v);
+
+        return 1;
+}
+
+static int client_ensure_duid(sd_dhcp6_client *client) {
+        if (client->duid_len != 0)
+                return 0;
+
+        return dhcp_identifier_set_duid_en(&client->duid, &client->duid_len);
+}
+
+/**
+ * Sets DUID. If duid is non-null, the DUID is set to duid_type + duid
+ * without further modification. Otherwise, if duid_type is supported, DUID
+ * is set based on that type. Otherwise, an error is returned.
+ */
+static int dhcp6_client_set_duid_internal(
+                sd_dhcp6_client *client,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len,
+                usec_t llt_time) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(duid_len == 0 || duid != NULL, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        if (duid) {
+                r = dhcp_validate_duid_len(duid_type, duid_len, true);
+                if (r < 0) {
+                        r = dhcp_validate_duid_len(duid_type, duid_len, false);
+                        if (r < 0)
+                                return log_dhcp6_client_errno(client, r, "Failed to validate length of DUID: %m");
+
+                        log_dhcp6_client(client, "Using DUID of type %u of incorrect length, proceeding.", duid_type);
+                }
+
+                client->duid.type = htobe16(duid_type);
+                memcpy(&client->duid.raw.data, duid, duid_len);
+                client->duid_len = sizeof(client->duid.type) + duid_len;
+        } else
+                switch (duid_type) {
+                case DUID_TYPE_LLT:
+                        if (client->mac_addr_len == 0)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EOPNOTSUPP), "Failed to set DUID-LLT, MAC address is not set.");
+
+                        r = dhcp_identifier_set_duid_llt(&client->duid, llt_time, client->mac_addr, client->mac_addr_len, client->arp_type, &client->duid_len);
+                        if (r < 0)
+                                return log_dhcp6_client_errno(client, r, "Failed to set DUID-LLT: %m");
+                        break;
+                case DUID_TYPE_EN:
+                        r = dhcp_identifier_set_duid_en(&client->duid, &client->duid_len);
+                        if (r < 0)
+                                return log_dhcp6_client_errno(client, r, "Failed to set DUID-EN: %m");
+                        break;
+                case DUID_TYPE_LL:
+                        if (client->mac_addr_len == 0)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EOPNOTSUPP), "Failed to set DUID-LL, MAC address is not set.");
+
+                        r = dhcp_identifier_set_duid_ll(&client->duid, client->mac_addr, client->mac_addr_len, client->arp_type, &client->duid_len);
+                        if (r < 0)
+                                return log_dhcp6_client_errno(client, r, "Failed to set DUID-LL: %m");
+                        break;
+                case DUID_TYPE_UUID:
+                        r = dhcp_identifier_set_duid_uuid(&client->duid, &client->duid_len);
+                        if (r < 0)
+                                return log_dhcp6_client_errno(client, r, "Failed to set DUID-UUID: %m");
+                        break;
+                default:
+                        return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "Invalid DUID type");
+                }
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_duid(
+                sd_dhcp6_client *client,
+                uint16_t duid_type,
+                const void *duid,
+                size_t duid_len) {
+        return dhcp6_client_set_duid_internal(client, duid_type, duid, duid_len, 0);
+}
+
+int sd_dhcp6_client_set_duid_llt(
+                sd_dhcp6_client *client,
+                usec_t llt_time) {
+        return dhcp6_client_set_duid_internal(client, DUID_TYPE_LLT, NULL, 0, llt_time);
+}
+
+static const char* const dhcp6_duid_type_table[_DUID_TYPE_MAX] = {
+        [DUID_TYPE_LLT]  = "DUID-LLT",
+        [DUID_TYPE_EN]   = "DUID-EN/Vendor",
+        [DUID_TYPE_LL]   = "DUID-LL",
+        [DUID_TYPE_UUID] = "UUID",
+};
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(dhcp6_duid_type, DUIDType);
+
+int sd_dhcp6_client_duid_as_string(
+                sd_dhcp6_client *client,
+                char **duid) {
+        _cleanup_free_ char *p = NULL, *s = NULL, *t = NULL;
+        const char *v;
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->duid_len > 0, -ENODATA);
+
+        v = dhcp6_duid_type_to_string(be16toh(client->duid.type));
+        if (v) {
+                s = strdup(v);
+                if (!s)
+                        return -ENOMEM;
+        } else {
+                r = asprintf(&s, "%0x", client->duid.type);
+                if (r < 0)
+                        return -ENOMEM;
+        }
+
+        t = hexmem(&client->duid.raw.data, client->duid_len);
+        if (!t)
+                return -ENOMEM;
+
+        p = strjoin(s, ":", t);
+        if (!p)
+                return -ENOMEM;
+
+        *duid = TAKE_PTR(p);
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_iaid(sd_dhcp6_client *client, uint32_t iaid) {
+        assert_return(client, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        client->ia_na.ia_na.id = htobe32(iaid);
+        client->ia_pd.ia_pd.id = htobe32(iaid);
+        client->iaid_set = true;
+
+        return 0;
+}
+
+int sd_dhcp6_client_get_iaid(sd_dhcp6_client *client, uint32_t *iaid) {
+        assert_return(client, -EINVAL);
+        assert_return(iaid, -EINVAL);
+
+        if (!client->iaid_set)
+                return -ENODATA;
+
+        *iaid = be32toh(client->ia_na.ia_na.id);
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_fqdn(
+                sd_dhcp6_client *client,
+                const char *fqdn) {
+
+        assert_return(client, -EINVAL);
+
+        /* Make sure FQDN qualifies as DNS and as Linux hostname */
+        if (fqdn &&
+            !(hostname_is_valid(fqdn, false) && dns_name_is_valid(fqdn) > 0))
+                return -EINVAL;
+
+        return free_and_strdup(&client->fqdn, fqdn);
+}
+
+int sd_dhcp6_client_set_information_request(sd_dhcp6_client *client, int enabled) {
+        assert_return(client, -EINVAL);
+        assert_return(IN_SET(client->state, DHCP6_STATE_STOPPED), -EBUSY);
+
+        client->information_request = enabled;
+
+        return 0;
+}
+
+int sd_dhcp6_client_get_information_request(sd_dhcp6_client *client, int *enabled) {
+        assert_return(client, -EINVAL);
+        assert_return(enabled, -EINVAL);
+
+        *enabled = client->information_request;
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_request_option(sd_dhcp6_client *client, uint16_t option) {
+        size_t t;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->state == DHCP6_STATE_STOPPED, -EBUSY);
+
+        if (option <= 0 || option >= UINT8_MAX)
+                return -EINVAL;
+
+        for (t = 0; t < client->req_opts_len; t++)
+                if (client->req_opts[t] == htobe16(option))
+                        return -EEXIST;
+
+        if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
+                            client->req_opts_len + 1))
+                return -ENOMEM;
+
+        client->req_opts[client->req_opts_len++] = htobe16(option);
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_request_mud_url(sd_dhcp6_client *client, const char *mudurl) {
+
+        assert_return(client, -EINVAL);
+        assert_return(client->state == DHCP6_STATE_STOPPED, -EBUSY);
+        assert_return(mudurl, -EINVAL);
+        assert_return(strlen(mudurl) <= UINT8_MAX, -EINVAL);
+        assert_return(http_url_is_valid(mudurl), -EINVAL);
+
+        return free_and_strdup(&client->mudurl, mudurl);
+}
+
+int sd_dhcp6_client_set_request_user_class(sd_dhcp6_client *client, char * const *user_class) {
+        char * const *p;
+        char **s;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->state == DHCP6_STATE_STOPPED, -EBUSY);
+        assert_return(!strv_isempty(user_class), -EINVAL);
+
+        STRV_FOREACH(p, user_class) {
+                size_t len = strlen(*p);
+
+                if (len > UINT16_MAX || len == 0)
+                        return -EINVAL;
+        }
+
+        s = strv_copy(user_class);
+        if (!s)
+                return -ENOMEM;
+
+        return strv_free_and_replace(client->user_class, s);
+}
+
+int sd_dhcp6_client_set_request_vendor_class(sd_dhcp6_client *client, char * const *vendor_class) {
+        char * const *p;
+        char **s;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->state == DHCP6_STATE_STOPPED, -EBUSY);
+        assert_return(!strv_isempty(vendor_class), -EINVAL);
+
+        STRV_FOREACH(p, vendor_class) {
+                size_t len = strlen(*p);
+
+                if (len > UINT16_MAX || len == 0)
+                        return -EINVAL;
+        }
+
+        s = strv_copy(vendor_class);
+        if (!s)
+                return -ENOMEM;
+
+        return strv_free_and_replace(client->vendor_class, s);
+}
+
+int sd_dhcp6_client_get_prefix_delegation(sd_dhcp6_client *client, int *delegation) {
+        assert_return(client, -EINVAL);
+        assert_return(delegation, -EINVAL);
+
+        *delegation = FLAGS_SET(client->request, DHCP6_REQUEST_IA_PD);
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_prefix_delegation(sd_dhcp6_client *client, int delegation) {
+        assert_return(client, -EINVAL);
+
+        SET_FLAG(client->request, DHCP6_REQUEST_IA_PD, delegation);
+
+        return 0;
+}
+
+int sd_dhcp6_client_get_address_request(sd_dhcp6_client *client, int *request) {
+        assert_return(client, -EINVAL);
+        assert_return(request, -EINVAL);
+
+        *request = FLAGS_SET(client->request, DHCP6_REQUEST_IA_NA);
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_address_request(sd_dhcp6_client *client, int request) {
+        assert_return(client, -EINVAL);
+
+        SET_FLAG(client->request, DHCP6_REQUEST_IA_NA, request);
+
+        return 0;
+}
+
+int sd_dhcp6_client_set_transaction_id(sd_dhcp6_client *client, uint32_t transaction_id) {
+        assert_return(client, -EINVAL);
+
+        client->transaction_id = transaction_id;
+
+        return 0;
+}
+
+int sd_dhcp6_client_get_lease(sd_dhcp6_client *client, sd_dhcp6_lease **ret) {
+        assert_return(client, -EINVAL);
+
+        if (!client->lease)
+                return -ENOMSG;
+
+        if (ret)
+                *ret = client->lease;
+
+        return 0;
+}
+
+int sd_dhcp6_client_add_option(sd_dhcp6_client *client, sd_dhcp6_option *v) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(v, -EINVAL);
+
+        r = ordered_hashmap_ensure_allocated(&client->extra_options, &dhcp6_option_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = ordered_hashmap_put(client->extra_options, UINT_TO_PTR(v->option), v);
+        if (r < 0)
+                return r;
+
+        sd_dhcp6_option_ref(v);
+        return 0;
+}
+
+static void client_notify(sd_dhcp6_client *client, int event) {
+        assert(client);
+
+        if (client->callback)
+                client->callback(client, event, client->userdata);
+}
+
+static int client_reset(sd_dhcp6_client *client) {
+        assert(client);
+
+        client->lease = sd_dhcp6_lease_unref(client->lease);
+
+        client->receive_message =
+                sd_event_source_unref(client->receive_message);
+
+        client->transaction_id = 0;
+        client->transaction_start = 0;
+
+        client->retransmit_time = 0;
+        client->retransmit_count = 0;
+
+        (void) event_source_disable(client->timeout_resend);
+        (void) event_source_disable(client->timeout_resend_expire);
+        (void) event_source_disable(client->timeout_t1);
+        (void) event_source_disable(client->timeout_t2);
+
+        client->state = DHCP6_STATE_STOPPED;
+
+        return 0;
+}
+
+static void client_stop(sd_dhcp6_client *client, int error) {
+        DHCP6_CLIENT_DONT_DESTROY(client);
+
+        assert(client);
+
+        client_notify(client, error);
+
+        client_reset(client);
+}
+
+static int client_send_message(sd_dhcp6_client *client, usec_t time_now) {
+        _cleanup_free_ DHCP6Message *message = NULL;
+        struct in6_addr all_servers =
+                IN6ADDR_ALL_DHCP6_RELAY_AGENTS_AND_SERVERS_INIT;
+        struct sd_dhcp6_option *j;
+        size_t len, optlen = 512;
+        uint8_t *opt;
+        int r;
+        usec_t elapsed_usec;
+        be16_t elapsed_time;
+
+        assert(client);
+
+        len = sizeof(DHCP6Message) + optlen;
+
+        message = malloc0(len);
+        if (!message)
+                return -ENOMEM;
+
+        opt = (uint8_t *)(message + 1);
+
+        message->transaction_id = client->transaction_id;
+
+        switch(client->state) {
+        case DHCP6_STATE_INFORMATION_REQUEST:
+                message->type = DHCP6_INFORMATION_REQUEST;
+
+                if (client->mudurl) {
+                        r = dhcp6_option_append(&opt, &optlen,
+                                                SD_DHCP6_OPTION_MUD_URL, strlen(client->mudurl),
+                                                client->mudurl);
+                        if (r < 0)
+                                return r;
+                }
+
+                break;
+
+        case DHCP6_STATE_SOLICITATION:
+                message->type = DHCP6_SOLICIT;
+
+                r = dhcp6_option_append(&opt, &optlen,
+                                        SD_DHCP6_OPTION_RAPID_COMMIT, 0, NULL);
+                if (r < 0)
+                        return r;
+
+                if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_NA)) {
+                        r = dhcp6_option_append_ia(&opt, &optlen,
+                                                   &client->ia_na);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->fqdn) {
+                        r = dhcp6_option_append_fqdn(&opt, &optlen, client->fqdn);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->mudurl) {
+                        r = dhcp6_option_append(&opt, &optlen,
+                                                SD_DHCP6_OPTION_MUD_URL, strlen(client->mudurl),
+                                                client->mudurl);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->user_class) {
+                        r = dhcp6_option_append_user_class(&opt, &optlen, client->user_class);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->vendor_class) {
+                        r = dhcp6_option_append_vendor_class(&opt, &optlen, client->vendor_class);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (!ordered_hashmap_isempty(client->vendor_options)) {
+                        r = dhcp6_option_append_vendor_option(&opt, &optlen,
+                                                       client->vendor_options);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_PD)) {
+                        r = dhcp6_option_append_pd(opt, optlen, &client->ia_pd, &client->hint_pd_prefix);
+                        if (r < 0)
+                                return r;
+
+                        opt += r;
+                        optlen -= r;
+                }
+
+                break;
+
+        case DHCP6_STATE_REQUEST:
+        case DHCP6_STATE_RENEW:
+
+                if (client->state == DHCP6_STATE_REQUEST)
+                        message->type = DHCP6_REQUEST;
+                else
+                        message->type = DHCP6_RENEW;
+
+                r = dhcp6_option_append(&opt, &optlen, SD_DHCP6_OPTION_SERVERID,
+                                        client->lease->serverid_len,
+                                        client->lease->serverid);
+                if (r < 0)
+                        return r;
+
+                if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_NA) && client->lease->ia.addresses) {
+                        r = dhcp6_option_append_ia(&opt, &optlen,
+                                                   &client->lease->ia);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->fqdn) {
+                        r = dhcp6_option_append_fqdn(&opt, &optlen, client->fqdn);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->mudurl) {
+                        r = dhcp6_option_append(&opt, &optlen,
+                                                SD_DHCP6_OPTION_MUD_URL, strlen(client->mudurl),
+                                                client->mudurl);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->user_class) {
+                        r = dhcp6_option_append_user_class(&opt, &optlen, client->user_class);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->vendor_class) {
+                        r = dhcp6_option_append_vendor_class(&opt, &optlen, client->vendor_class);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (!ordered_hashmap_isempty(client->vendor_options)) {
+                        r = dhcp6_option_append_vendor_option(&opt, &optlen, client->vendor_options);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_PD) && client->lease->pd.addresses) {
+                        r = dhcp6_option_append_pd(opt, optlen, &client->lease->pd, NULL);
+                        if (r < 0)
+                                return r;
+
+                        opt += r;
+                        optlen -= r;
+                }
+
+                break;
+
+        case DHCP6_STATE_REBIND:
+                message->type = DHCP6_REBIND;
+
+                if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_NA)) {
+                        r = dhcp6_option_append_ia(&opt, &optlen, &client->lease->ia);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->fqdn) {
+                        r = dhcp6_option_append_fqdn(&opt, &optlen, client->fqdn);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->mudurl) {
+                        r = dhcp6_option_append(&opt, &optlen,
+                                                SD_DHCP6_OPTION_MUD_URL, strlen(client->mudurl),
+                                                client->mudurl);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->user_class) {
+                        r = dhcp6_option_append_user_class(&opt, &optlen, client->user_class);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (client->vendor_class) {
+                        r = dhcp6_option_append_vendor_class(&opt, &optlen, client->vendor_class);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (!ordered_hashmap_isempty(client->vendor_options)) {
+                        r = dhcp6_option_append_vendor_option(&opt, &optlen, client->vendor_options);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_PD)) {
+                        r = dhcp6_option_append_pd(opt, optlen, &client->lease->pd, NULL);
+                        if (r < 0)
+                                return r;
+
+                        opt += r;
+                        optlen -= r;
+                }
+
+                break;
+
+        case DHCP6_STATE_STOPPED:
+        case DHCP6_STATE_BOUND:
+                return -EINVAL;
+        }
+
+        r = dhcp6_option_append(&opt, &optlen, SD_DHCP6_OPTION_ORO,
+                                client->req_opts_len * sizeof(be16_t),
+                                client->req_opts);
+        if (r < 0)
+                return r;
+
+        assert(client->duid_len);
+        r = dhcp6_option_append(&opt, &optlen, SD_DHCP6_OPTION_CLIENTID,
+                                client->duid_len, &client->duid);
+        if (r < 0)
+                return r;
+
+        elapsed_usec = time_now - client->transaction_start;
+        if (elapsed_usec < 0xffff * USEC_PER_MSEC * 10)
+                elapsed_time = htobe16(elapsed_usec / USEC_PER_MSEC / 10);
+        else
+                elapsed_time = 0xffff;
+
+        r = dhcp6_option_append(&opt, &optlen, SD_DHCP6_OPTION_ELAPSED_TIME,
+                                sizeof(elapsed_time), &elapsed_time);
+        if (r < 0)
+                return r;
+
+        ORDERED_HASHMAP_FOREACH(j, client->extra_options) {
+                r = dhcp6_option_append(&opt, &optlen, j->option, j->length, j->data);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp6_network_send_udp_socket(client->fd, &all_servers, message,
+                                          len - optlen);
+        if (r < 0)
+                return r;
+
+        log_dhcp6_client(client, "Sent %s",
+                         dhcp6_message_type_to_string(message->type));
+
+        return 0;
+}
+
+static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_dhcp6_client *client = userdata;
+
+        assert(s);
+        assert(client);
+        assert(client->lease);
+
+        (void) event_source_disable(client->timeout_t2);
+
+        log_dhcp6_client(client, "Timeout T2");
+
+        client_start(client, DHCP6_STATE_REBIND);
+
+        return 0;
+}
+
+static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_dhcp6_client *client = userdata;
+
+        assert(s);
+        assert(client);
+        assert(client->lease);
+
+        (void) event_source_disable(client->timeout_t1);
+
+        log_dhcp6_client(client, "Timeout T1");
+
+        client_start(client, DHCP6_STATE_RENEW);
+
+        return 0;
+}
+
+static int client_timeout_resend_expire(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_dhcp6_client *client = userdata;
+        DHCP6_CLIENT_DONT_DESTROY(client);
+        enum DHCP6State state;
+
+        assert(s);
+        assert(client);
+        assert(client->event);
+
+        state = client->state;
+
+        client_stop(client, SD_DHCP6_CLIENT_EVENT_RESEND_EXPIRE);
+
+        /* RFC 3315, section 18.1.4., says that "...the client may choose to
+           use a Solicit message to locate a new DHCP server..." */
+        if (state == DHCP6_STATE_REBIND)
+                client_start(client, DHCP6_STATE_SOLICITATION);
+
+        return 0;
+}
+
+static usec_t client_timeout_compute_random(usec_t val) {
+        return val - (random_u32() % USEC_PER_SEC) * val / 10 / USEC_PER_SEC;
+}
+
+static int client_timeout_resend(sd_event_source *s, uint64_t usec, void *userdata) {
+        int r = 0;
+        sd_dhcp6_client *client = userdata;
+        usec_t time_now, init_retransmit_time = 0, max_retransmit_time = 0;
+        usec_t max_retransmit_duration = 0;
+        uint8_t max_retransmit_count = 0;
+        char time_string[FORMAT_TIMESPAN_MAX];
+
+        assert(s);
+        assert(client);
+        assert(client->event);
+
+        (void) event_source_disable(client->timeout_resend);
+
+        switch (client->state) {
+        case DHCP6_STATE_INFORMATION_REQUEST:
+                init_retransmit_time = DHCP6_INF_TIMEOUT;
+                max_retransmit_time = DHCP6_INF_MAX_RT;
+
+                break;
+
+        case DHCP6_STATE_SOLICITATION:
+
+                if (client->retransmit_count && client->lease) {
+                        client_start(client, DHCP6_STATE_REQUEST);
+                        return 0;
+                }
+
+                init_retransmit_time = DHCP6_SOL_TIMEOUT;
+                max_retransmit_time = DHCP6_SOL_MAX_RT;
+
+                break;
+
+        case DHCP6_STATE_REQUEST:
+                init_retransmit_time = DHCP6_REQ_TIMEOUT;
+                max_retransmit_time = DHCP6_REQ_MAX_RT;
+                max_retransmit_count = DHCP6_REQ_MAX_RC;
+
+                break;
+
+        case DHCP6_STATE_RENEW:
+                init_retransmit_time = DHCP6_REN_TIMEOUT;
+                max_retransmit_time = DHCP6_REN_MAX_RT;
+
+                /* RFC 3315, section 18.1.3. says max retransmit duration will
+                   be the remaining time until T2. Instead of setting MRD,
+                   wait for T2 to trigger with the same end result */
+
+                break;
+
+        case DHCP6_STATE_REBIND:
+                init_retransmit_time = DHCP6_REB_TIMEOUT;
+                max_retransmit_time = DHCP6_REB_MAX_RT;
+
+                if (event_source_is_enabled(client->timeout_resend_expire) <= 0) {
+                        uint32_t expire = 0;
+
+                        r = dhcp6_lease_ia_rebind_expire(&client->lease->ia, &expire);
+                        if (r < 0) {
+                                client_stop(client, r);
+                                return 0;
+                        }
+                        max_retransmit_duration = expire * USEC_PER_SEC;
+                }
+
+                break;
+
+        case DHCP6_STATE_STOPPED:
+        case DHCP6_STATE_BOUND:
+                return 0;
+        }
+
+        if (max_retransmit_count > 0 &&
+            client->retransmit_count >= max_retransmit_count) {
+                client_stop(client, SD_DHCP6_CLIENT_EVENT_RETRANS_MAX);
+                return 0;
+        }
+
+        r = sd_event_now(client->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                goto error;
+
+        r = client_send_message(client, time_now);
+        if (r >= 0)
+                client->retransmit_count++;
+
+        if (client->retransmit_time == 0) {
+                client->retransmit_time =
+                        client_timeout_compute_random(init_retransmit_time);
+
+                if (client->state == DHCP6_STATE_SOLICITATION)
+                        client->retransmit_time += init_retransmit_time / 10;
+
+        } else {
+                if (max_retransmit_time > 0 &&
+                    client->retransmit_time > max_retransmit_time / 2)
+                        client->retransmit_time = client_timeout_compute_random(max_retransmit_time);
+                else
+                        client->retransmit_time += client_timeout_compute_random(client->retransmit_time);
+        }
+
+        log_dhcp6_client(client, "Next retransmission in %s",
+                         format_timespan(time_string, FORMAT_TIMESPAN_MAX, client->retransmit_time, USEC_PER_SEC));
+
+        r = event_reset_time(client->event, &client->timeout_resend,
+                             clock_boottime_or_monotonic(),
+                             time_now + client->retransmit_time, 10 * USEC_PER_MSEC,
+                             client_timeout_resend, client,
+                             client->event_priority, "dhcp6-resend-timer", true);
+        if (r < 0)
+                goto error;
+
+        if (max_retransmit_duration > 0 && event_source_is_enabled(client->timeout_resend_expire) <= 0) {
+
+                log_dhcp6_client(client, "Max retransmission duration %"PRIu64" secs",
+                                 max_retransmit_duration / USEC_PER_SEC);
+
+                r = event_reset_time(client->event, &client->timeout_resend_expire,
+                                     clock_boottime_or_monotonic(),
+                                     time_now + max_retransmit_duration, USEC_PER_SEC,
+                                     client_timeout_resend_expire, client,
+                                     client->event_priority, "dhcp6-resend-expire-timer", true);
+                if (r < 0)
+                        goto error;
+        }
+
+error:
+        if (r < 0)
+                client_stop(client, r);
+
+        return 0;
+}
+
+static int client_ensure_iaid(sd_dhcp6_client *client) {
+        int r;
+        uint32_t iaid;
+
+        assert(client);
+
+        if (client->iaid_set)
+                return 0;
+
+        r = dhcp_identifier_set_iaid(client->ifindex, client->mac_addr, client->mac_addr_len, true, &iaid);
+        if (r < 0)
+                return r;
+
+        client->ia_na.ia_na.id = iaid;
+        client->ia_pd.ia_pd.id = iaid;
+        client->iaid_set = true;
+
+        return 0;
+}
+
+static int client_parse_message(
+                sd_dhcp6_client *client,
+                DHCP6Message *message,
+                size_t len,
+                sd_dhcp6_lease *lease) {
+
+        uint16_t ia_na_status = 0, ia_pd_status = 0;
+        uint32_t lt_t1 = ~0, lt_t2 = ~0;
+        usec_t irt = IRT_DEFAULT;
+        bool clientid = false;
+        size_t pos = 0;
+        int r;
+
+        assert(client);
+        assert(message);
+        assert(len >= sizeof(DHCP6Message));
+        assert(lease);
+
+        len -= sizeof(DHCP6Message);
+
+        while (pos < len) {
+                DHCP6Option *option = (DHCP6Option *) &message->options[pos];
+                uint16_t optcode, optlen;
+                be32_t iaid_lease;
+                int  status;
+                uint8_t *optval;
+
+                if (len < pos + offsetof(DHCP6Option, data))
+                        return -ENOBUFS;
+
+                optcode = be16toh(option->code);
+                optlen = be16toh(option->len);
+                optval = option->data;
+
+                if (len < pos + offsetof(DHCP6Option, data) + optlen)
+                        return -ENOBUFS;
+
+                switch (optcode) {
+                case SD_DHCP6_OPTION_CLIENTID:
+                        if (clientid) {
+                                log_dhcp6_client(client, "%s contains multiple clientids",
+                                                 dhcp6_message_type_to_string(message->type));
+                                return -EINVAL;
+                        }
+
+                        if (optlen != client->duid_len ||
+                            memcmp(&client->duid, optval, optlen) != 0) {
+                                log_dhcp6_client(client, "%s DUID does not match",
+                                                 dhcp6_message_type_to_string(message->type));
+
+                                return -EINVAL;
+                        }
+                        clientid = true;
+
+                        break;
+
+                case SD_DHCP6_OPTION_SERVERID:
+                        r = dhcp6_lease_get_serverid(lease, NULL, NULL);
+                        if (r >= 0) {
+                                log_dhcp6_client(client, "%s contains multiple serverids",
+                                                 dhcp6_message_type_to_string(message->type));
+                                return -EINVAL;
+                        }
+
+                        r = dhcp6_lease_set_serverid(lease, optval, optlen);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_PREFERENCE:
+                        if (optlen != 1)
+                                return -EINVAL;
+
+                        r = dhcp6_lease_set_preference(lease, optval[0]);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_STATUS_CODE:
+                        status = dhcp6_option_parse_status(option, optlen + sizeof(DHCP6Option));
+                        if (status < 0)
+                                return status;
+
+                        if (status > 0) {
+                                log_dhcp6_client(client, "%s Status %s",
+                                                 dhcp6_message_type_to_string(message->type),
+                                                 dhcp6_message_status_to_string(status));
+
+                                return -EINVAL;
+                        }
+
+                        break;
+
+                case SD_DHCP6_OPTION_IA_NA:
+                        if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
+                                log_dhcp6_client(client, "Information request ignoring IA NA option");
+
+                                break;
+                        }
+
+                        r = dhcp6_option_parse_ia(option, &lease->ia, &ia_na_status);
+                        if (r < 0 && r != -ENOMSG)
+                                return r;
+
+                        if (ia_na_status == DHCP6_STATUS_NO_ADDRS_AVAIL) {
+                                pos += offsetof(DHCP6Option, data) + optlen;
+                                continue;
+                        }
+
+                        r = dhcp6_lease_get_iaid(lease, &iaid_lease);
+                        if (r < 0)
+                                return r;
+
+                        if (client->ia_na.ia_na.id != iaid_lease) {
+                                log_dhcp6_client(client, "%s has wrong IAID for IA NA",
+                                                 dhcp6_message_type_to_string(message->type));
+                                return -EINVAL;
+                        }
+
+                        if (lease->ia.addresses) {
+                                lt_t1 = MIN(lt_t1, be32toh(lease->ia.ia_na.lifetime_t1));
+                                lt_t2 = MIN(lt_t2, be32toh(lease->ia.ia_na.lifetime_t1));
+                        }
+
+                        break;
+
+                case SD_DHCP6_OPTION_IA_PD:
+                        if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
+                                log_dhcp6_client(client, "Information request ignoring IA PD option");
+
+                                break;
+                        }
+
+                        r = dhcp6_option_parse_ia(option, &lease->pd, &ia_pd_status);
+                        if (r < 0 && r != -ENOMSG)
+                                return r;
+
+                        if (ia_pd_status == DHCP6_STATUS_NO_PREFIX_AVAIL) {
+                                pos += offsetof(DHCP6Option, data) + optlen;
+                                continue;
+                        }
+
+                        r = dhcp6_lease_get_pd_iaid(lease, &iaid_lease);
+                        if (r < 0)
+                                return r;
+
+                        if (client->ia_pd.ia_pd.id != iaid_lease) {
+                                log_dhcp6_client(client, "%s has wrong IAID for IA PD",
+                                                 dhcp6_message_type_to_string(message->type));
+                                return -EINVAL;
+                        }
+
+                        if (lease->pd.addresses) {
+                                lt_t1 = MIN(lt_t1, be32toh(lease->pd.ia_pd.lifetime_t1));
+                                lt_t2 = MIN(lt_t2, be32toh(lease->pd.ia_pd.lifetime_t2));
+                        }
+
+                        break;
+
+                case SD_DHCP6_OPTION_RAPID_COMMIT:
+                        r = dhcp6_lease_set_rapid_commit(lease);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_DNS_SERVERS:
+                        r = dhcp6_lease_set_dns(lease, optval, optlen);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_DOMAIN_LIST:
+                        r = dhcp6_lease_set_domains(lease, optval, optlen);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_NTP_SERVER:
+                        r = dhcp6_lease_set_ntp(lease, optval, optlen);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_SNTP_SERVERS:
+                        r = dhcp6_lease_set_sntp(lease, optval, optlen);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_FQDN:
+                        r = dhcp6_lease_set_fqdn(lease, optval, optlen);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                case SD_DHCP6_OPTION_INFORMATION_REFRESH_TIME:
+                        if (optlen != 4)
+                                return -EINVAL;
+
+                        irt = unaligned_read_be32((be32_t *) optval) * USEC_PER_SEC;
+                        break;
+                }
+
+                pos += offsetof(DHCP6Option, data) + optlen;
+        }
+
+        if (ia_na_status > 0 && ia_pd_status > 0) {
+                log_dhcp6_client(client, "No IA_PD prefix or IA_NA address received. Ignoring.");
+                return -EINVAL;
+        }
+
+        if (!clientid) {
+                log_dhcp6_client(client, "%s has incomplete options",
+                                 dhcp6_message_type_to_string(message->type));
+                return -EINVAL;
+        }
+
+        if (client->state != DHCP6_STATE_INFORMATION_REQUEST) {
+                r = dhcp6_lease_get_serverid(lease, NULL, NULL);
+                if (r < 0) {
+                        log_dhcp6_client(client, "%s has no server id",
+                                         dhcp6_message_type_to_string(message->type));
+                        return -EINVAL;
+                }
+
+        } else {
+                if (lease->ia.addresses) {
+                        lease->ia.ia_na.lifetime_t1 = htobe32(lt_t1);
+                        lease->ia.ia_na.lifetime_t2 = htobe32(lt_t2);
+                }
+
+                if (lease->pd.addresses) {
+                        lease->pd.ia_pd.lifetime_t1 = htobe32(lt_t1);
+                        lease->pd.ia_pd.lifetime_t2 = htobe32(lt_t2);
+                }
+        }
+
+        client->information_refresh_time_usec = MAX(irt, IRT_MINIMUM);
+
+        return 0;
+}
+
+static int client_receive_reply(sd_dhcp6_client *client, DHCP6Message *reply, size_t len) {
+        _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease = NULL;
+        bool rapid_commit;
+        int r;
+
+        assert(client);
+        assert(reply);
+
+        if (reply->type != DHCP6_REPLY)
+                return 0;
+
+        r = dhcp6_lease_new(&lease);
+        if (r < 0)
+                return -ENOMEM;
+
+        r = client_parse_message(client, reply, len, lease);
+        if (r < 0)
+                return r;
+
+        if (client->state == DHCP6_STATE_SOLICITATION) {
+                r = dhcp6_lease_get_rapid_commit(lease, &rapid_commit);
+                if (r < 0)
+                        return r;
+
+                if (!rapid_commit)
+                        return 0;
+        }
+
+        sd_dhcp6_lease_unref(client->lease);
+        client->lease = TAKE_PTR(lease);
+
+        return DHCP6_STATE_BOUND;
+}
+
+static int client_receive_advertise(sd_dhcp6_client *client, DHCP6Message *advertise, size_t len) {
+        _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease = NULL;
+        uint8_t pref_advertise = 0, pref_lease = 0;
+        int r;
+
+        if (advertise->type != DHCP6_ADVERTISE)
+                return 0;
+
+        r = dhcp6_lease_new(&lease);
+        if (r < 0)
+                return r;
+
+        r = client_parse_message(client, advertise, len, lease);
+        if (r < 0)
+                return r;
+
+        r = dhcp6_lease_get_preference(lease, &pref_advertise);
+        if (r < 0)
+                return r;
+
+        r = dhcp6_lease_get_preference(client->lease, &pref_lease);
+
+        if (r < 0 || pref_advertise > pref_lease) {
+                sd_dhcp6_lease_unref(client->lease);
+                client->lease = TAKE_PTR(lease);
+                r = 0;
+        }
+
+        if (pref_advertise == 255 || client->retransmit_count > 1)
+                r = DHCP6_STATE_REQUEST;
+
+        return r;
+}
+
+static int client_receive_message(
+                sd_event_source *s,
+                int fd, uint32_t
+                revents,
+                void *userdata) {
+
+        sd_dhcp6_client *client = userdata;
+        DHCP6_CLIENT_DONT_DESTROY(client);
+        _cleanup_free_ DHCP6Message *message = NULL;
+        ssize_t buflen, len;
+        int r = 0;
+
+        assert(s);
+        assert(client);
+        assert(client->event);
+
+        buflen = next_datagram_size_fd(fd);
+        if (buflen == -ENETDOWN)
+                /* the link is down. Don't return an error or the I/O event
+                   source will be disconnected and we won't be able to receive
+                   packets again when the link comes back. */
+                return 0;
+        if (buflen < 0)
+                return buflen;
+
+        message = malloc(buflen);
+        if (!message)
+                return -ENOMEM;
+
+        len = recv(fd, message, buflen, 0);
+        if (len < 0) {
+                /* see comment above for why we shouldn't error out on ENETDOWN. */
+                if (IN_SET(errno, EAGAIN, EINTR, ENETDOWN))
+                        return 0;
+
+                return log_dhcp6_client_errno(client, errno, "Could not receive message from UDP socket: %m");
+
+        }
+        if ((size_t) len < sizeof(DHCP6Message)) {
+                log_dhcp6_client(client, "Too small to be DHCP6 message: ignoring");
+                return 0;
+        }
+
+        switch(message->type) {
+        case DHCP6_SOLICIT:
+        case DHCP6_REQUEST:
+        case DHCP6_CONFIRM:
+        case DHCP6_RENEW:
+        case DHCP6_REBIND:
+        case DHCP6_RELEASE:
+        case DHCP6_DECLINE:
+        case DHCP6_INFORMATION_REQUEST:
+        case DHCP6_RELAY_FORW:
+        case DHCP6_RELAY_REPL:
+                return 0;
+
+        case DHCP6_ADVERTISE:
+        case DHCP6_REPLY:
+        case DHCP6_RECONFIGURE:
+                break;
+
+        default:
+                log_dhcp6_client(client, "Unknown message type %d", message->type);
+                return 0;
+        }
+
+        if (client->transaction_id != (message->transaction_id &
+                                       htobe32(0x00ffffff)))
+                return 0;
+
+        switch (client->state) {
+        case DHCP6_STATE_INFORMATION_REQUEST:
+                r = client_receive_reply(client, message, len);
+                if (r < 0)
+                        return 0;
+
+                client_notify(client, SD_DHCP6_CLIENT_EVENT_INFORMATION_REQUEST);
+
+                client_start(client, DHCP6_STATE_STOPPED);
+
+                break;
+
+        case DHCP6_STATE_SOLICITATION:
+                r = client_receive_advertise(client, message, len);
+
+                if (r == DHCP6_STATE_REQUEST) {
+                        client_start(client, r);
+
+                        break;
+                }
+
+                _fallthrough_; /* for Solicitation Rapid Commit option check */
+        case DHCP6_STATE_REQUEST:
+        case DHCP6_STATE_RENEW:
+        case DHCP6_STATE_REBIND:
+
+                r = client_receive_reply(client, message, len);
+                if (r < 0)
+                        return 0;
+
+                if (r == DHCP6_STATE_BOUND) {
+
+                        r = client_start(client, DHCP6_STATE_BOUND);
+                        if (r < 0) {
+                                client_stop(client, r);
+                                return 0;
+                        }
+
+                        client_notify(client, SD_DHCP6_CLIENT_EVENT_IP_ACQUIRE);
+                }
+
+                break;
+
+        case DHCP6_STATE_BOUND:
+
+                break;
+
+        case DHCP6_STATE_STOPPED:
+                return 0;
+        }
+
+        log_dhcp6_client(client, "Recv %s",
+                         dhcp6_message_type_to_string(message->type));
+
+        return 0;
+}
+
+static int client_get_lifetime(sd_dhcp6_client *client, uint32_t *lifetime_t1,
+                               uint32_t *lifetime_t2) {
+        assert_return(client, -EINVAL);
+        assert_return(client->lease, -EINVAL);
+
+        if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_NA) && client->lease->ia.addresses) {
+                *lifetime_t1 = be32toh(client->lease->ia.ia_na.lifetime_t1);
+                *lifetime_t2 = be32toh(client->lease->ia.ia_na.lifetime_t2);
+
+                return 0;
+        }
+
+        if (FLAGS_SET(client->request, DHCP6_REQUEST_IA_PD) && client->lease->pd.addresses) {
+                *lifetime_t1 = be32toh(client->lease->pd.ia_pd.lifetime_t1);
+                *lifetime_t2 = be32toh(client->lease->pd.ia_pd.lifetime_t2);
+
+                return 0;
+        }
+
+        return -ENOMSG;
+}
+
+static int client_start(sd_dhcp6_client *client, enum DHCP6State state) {
+        int r;
+        usec_t timeout, time_now;
+        char time_string[FORMAT_TIMESPAN_MAX];
+        uint32_t lifetime_t1, lifetime_t2;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->event, -EINVAL);
+        assert_return(client->ifindex > 0, -EINVAL);
+        assert_return(client->state != state, -EINVAL);
+
+        (void) event_source_disable(client->timeout_resend_expire);
+        (void) event_source_disable(client->timeout_resend);
+        client->retransmit_time = 0;
+        client->retransmit_count = 0;
+
+        r = sd_event_now(client->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                return r;
+
+        if (!client->receive_message) {
+                r = sd_event_add_io(client->event, &client->receive_message,
+                                    client->fd, EPOLLIN, client_receive_message,
+                                    client);
+                if (r < 0)
+                        goto error;
+
+                r = sd_event_source_set_priority(client->receive_message,
+                                                 client->event_priority);
+                if (r < 0)
+                        goto error;
+
+                r = sd_event_source_set_description(client->receive_message,
+                                                    "dhcp6-receive-message");
+                if (r < 0)
+                        goto error;
+        }
+
+        switch (state) {
+        case DHCP6_STATE_STOPPED:
+                if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
+                        client->state = DHCP6_STATE_STOPPED;
+
+                        return 0;
+                }
+
+                _fallthrough_;
+        case DHCP6_STATE_SOLICITATION:
+                client->state = DHCP6_STATE_SOLICITATION;
+
+                break;
+
+        case DHCP6_STATE_INFORMATION_REQUEST:
+        case DHCP6_STATE_REQUEST:
+        case DHCP6_STATE_RENEW:
+        case DHCP6_STATE_REBIND:
+
+                client->state = state;
+
+                break;
+
+        case DHCP6_STATE_BOUND:
+
+                r = client_get_lifetime(client, &lifetime_t1, &lifetime_t2);
+                if (r < 0)
+                        goto error;
+
+                if (lifetime_t1 == 0xffffffff || lifetime_t2 == 0xffffffff) {
+                        log_dhcp6_client(client, "Infinite T1 0x%08x or T2 0x%08x",
+                                         lifetime_t1, lifetime_t2);
+
+                        return 0;
+                }
+
+                timeout = client_timeout_compute_random(lifetime_t1 * USEC_PER_SEC);
+
+                log_dhcp6_client(client, "T1 expires in %s",
+                                 format_timespan(time_string, FORMAT_TIMESPAN_MAX, timeout, USEC_PER_SEC));
+
+                r = event_reset_time(client->event, &client->timeout_t1,
+                                     clock_boottime_or_monotonic(),
+                                     time_now + timeout, 10 * USEC_PER_SEC,
+                                     client_timeout_t1, client,
+                                     client->event_priority, "dhcp6-t1-timeout", true);
+                if (r < 0)
+                        goto error;
+
+                timeout = client_timeout_compute_random(lifetime_t2 * USEC_PER_SEC);
+
+                log_dhcp6_client(client, "T2 expires in %s",
+                                 format_timespan(time_string, FORMAT_TIMESPAN_MAX, timeout, USEC_PER_SEC));
+
+                r = event_reset_time(client->event, &client->timeout_t2,
+                                     clock_boottime_or_monotonic(),
+                                     time_now + timeout, 10 * USEC_PER_SEC,
+                                     client_timeout_t2, client,
+                                     client->event_priority, "dhcp6-t2-timeout", true);
+                if (r < 0)
+                        goto error;
+
+                client->state = state;
+
+                return 0;
+        }
+
+        client->transaction_id = random_u32() & htobe32(0x00ffffff);
+        client->transaction_start = time_now;
+
+        r = event_reset_time(client->event, &client->timeout_resend,
+                             clock_boottime_or_monotonic(),
+                             0, 0,
+                             client_timeout_resend, client,
+                             client->event_priority, "dhcp6-resend-timeout", true);
+        if (r < 0)
+                goto error;
+
+        return 0;
+
+ error:
+        client_reset(client);
+        return r;
+}
+
+int sd_dhcp6_client_stop(sd_dhcp6_client *client) {
+        if (!client)
+                return 0;
+
+        client_stop(client, SD_DHCP6_CLIENT_EVENT_STOP);
+
+        client->fd = safe_close(client->fd);
+
+        return 0;
+}
+
+int sd_dhcp6_client_is_running(sd_dhcp6_client *client) {
+        assert_return(client, -EINVAL);
+
+        return client->state != DHCP6_STATE_STOPPED;
+}
+
+int sd_dhcp6_client_start(sd_dhcp6_client *client) {
+        enum DHCP6State state = DHCP6_STATE_SOLICITATION;
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(client->event, -EINVAL);
+        assert_return(client->ifindex > 0, -EINVAL);
+        assert_return(in_addr_is_link_local(AF_INET6, (const union in_addr_union *) &client->local_address) > 0, -EINVAL);
+
+        if (!IN_SET(client->state, DHCP6_STATE_STOPPED))
+                return -EBUSY;
+
+        if (!client->information_request && !client->request)
+                return -EINVAL;
+
+        r = client_reset(client);
+        if (r < 0)
+                return r;
+
+        r = client_ensure_iaid(client);
+        if (r < 0)
+                return r;
+
+        r = client_ensure_duid(client);
+        if (r < 0)
+                return r;
+
+        if (client->fd < 0) {
+                r = dhcp6_network_bind_udp_socket(client->ifindex, &client->local_address);
+                if (r < 0) {
+                        _cleanup_free_ char *p = NULL;
+
+                        (void) in_addr_to_string(AF_INET6, (const union in_addr_union*) &client->local_address, &p);
+                        return log_dhcp6_client_errno(client, r,
+                                                      "Failed to bind to UDP socket at address %s: %m", strna(p));
+                }
+
+                client->fd = r;
+        }
+
+        if (client->information_request) {
+                usec_t t = now(CLOCK_MONOTONIC);
+
+                if (t < usec_add(client->information_request_time_usec, client->information_refresh_time_usec))
+                        return 0;
+
+                client->information_request_time_usec = t;
+                state = DHCP6_STATE_INFORMATION_REQUEST;
+        }
+
+        log_dhcp6_client(client, "Started in %s mode",
+                         client->information_request ? "Information request" : "Managed");
+
+        return client_start(client, state);
+}
+
+int sd_dhcp6_client_attach_event(sd_dhcp6_client *client, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(client, -EINVAL);
+        assert_return(!client->event, -EBUSY);
+
+        if (event)
+                client->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&client->event);
+                if (r < 0)
+                        return 0;
+        }
+
+        client->event_priority = priority;
+
+        return 0;
+}
+
+int sd_dhcp6_client_detach_event(sd_dhcp6_client *client) {
+        assert_return(client, -EINVAL);
+
+        client->event = sd_event_unref(client->event);
+
+        return 0;
+}
+
+sd_event *sd_dhcp6_client_get_event(sd_dhcp6_client *client) {
+        assert_return(client, NULL);
+
+        return client->event;
+}
+
+static sd_dhcp6_client *dhcp6_client_free(sd_dhcp6_client *client) {
+        assert(client);
+
+        client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+        client->timeout_resend_expire = sd_event_source_unref(client->timeout_resend_expire);
+        client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
+        client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
+
+        client_reset(client);
+
+        client->fd = safe_close(client->fd);
+
+        sd_dhcp6_client_detach_event(client);
+
+        free(client->req_opts);
+        free(client->fqdn);
+        free(client->mudurl);
+
+        ordered_hashmap_free(client->extra_options);
+        strv_free(client->user_class);
+        strv_free(client->vendor_class);
+
+        return mfree(client);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp6_client, sd_dhcp6_client, dhcp6_client_free);
+
+int sd_dhcp6_client_new(sd_dhcp6_client **ret) {
+        _cleanup_(sd_dhcp6_client_unrefp) sd_dhcp6_client *client = NULL;
+        _cleanup_free_ be16_t *req_opts = NULL;
+        size_t t;
+
+        assert_return(ret, -EINVAL);
+
+        req_opts = new(be16_t, ELEMENTSOF(default_req_opts));
+        if (!req_opts)
+                return -ENOMEM;
+
+        for (t = 0; t < ELEMENTSOF(default_req_opts); t++)
+                req_opts[t] = htobe16(default_req_opts[t]);
+
+        client = new(sd_dhcp6_client, 1);
+        if (!client)
+                return -ENOMEM;
+
+        *client = (sd_dhcp6_client) {
+                .n_ref = 1,
+                .ia_na.type = SD_DHCP6_OPTION_IA_NA,
+                .ia_pd.type = SD_DHCP6_OPTION_IA_PD,
+                .ifindex = -1,
+                .request = DHCP6_REQUEST_IA_NA,
+                .fd = -1,
+                .req_opts_len = ELEMENTSOF(default_req_opts),
+                .hint_pd_prefix.iapdprefix.lifetime_preferred = (be32_t) -1,
+                .hint_pd_prefix.iapdprefix.lifetime_valid = (be32_t) -1,
+                .req_opts = TAKE_PTR(req_opts),
+        };
+
+        *ret = TAKE_PTR(client);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/sd-dhcp6-lease.c b/src/libsystemd-network/sd-dhcp6-lease.c
new file mode 100644
index 0000000..d6f0708
--- /dev/null
+++ b/src/libsystemd-network/sd-dhcp6-lease.c
@@ -0,0 +1,433 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014-2015 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+
+#include "alloc-util.h"
+#include "dhcp6-lease-internal.h"
+#include "dhcp6-protocol.h"
+#include "strv.h"
+#include "util.h"
+
+int dhcp6_lease_ia_rebind_expire(const DHCP6IA *ia, uint32_t *expire) {
+        DHCP6Address *addr;
+        uint32_t valid = 0, t;
+
+        assert_return(ia, -EINVAL);
+        assert_return(expire, -EINVAL);
+
+        LIST_FOREACH(addresses, addr, ia->addresses) {
+                t = be32toh(addr->iaaddr.lifetime_valid);
+                if (valid < t)
+                        valid = t;
+        }
+
+        t = be32toh(ia->ia_na.lifetime_t2);
+        if (t > valid)
+                return -EINVAL;
+
+        *expire = valid - t;
+
+        return 0;
+}
+
+DHCP6IA *dhcp6_lease_free_ia(DHCP6IA *ia) {
+        DHCP6Address *address;
+
+        if (!ia)
+                return NULL;
+
+        while (ia->addresses) {
+                address = ia->addresses;
+
+                LIST_REMOVE(addresses, ia->addresses, address);
+
+                free(address);
+        }
+
+        return NULL;
+}
+
+int dhcp6_lease_set_serverid(sd_dhcp6_lease *lease, const uint8_t *id,
+                             size_t len) {
+        uint8_t *serverid;
+
+        assert_return(lease, -EINVAL);
+        assert_return(id, -EINVAL);
+
+        serverid = memdup(id, len);
+        if (!serverid)
+                return -ENOMEM;
+
+        free_and_replace(lease->serverid, serverid);
+        lease->serverid_len = len;
+
+        return 0;
+}
+
+int dhcp6_lease_get_serverid(sd_dhcp6_lease *lease, uint8_t **id, size_t *len) {
+        assert_return(lease, -EINVAL);
+
+        if (!lease->serverid)
+                return -ENOMSG;
+
+        if (id)
+                *id = lease->serverid;
+        if (len)
+                *len = lease->serverid_len;
+
+        return 0;
+}
+
+int dhcp6_lease_set_preference(sd_dhcp6_lease *lease, uint8_t preference) {
+        assert_return(lease, -EINVAL);
+
+        lease->preference = preference;
+
+        return 0;
+}
+
+int dhcp6_lease_get_preference(sd_dhcp6_lease *lease, uint8_t *preference) {
+        assert_return(preference, -EINVAL);
+
+        if (!lease)
+                return -EINVAL;
+
+        *preference = lease->preference;
+
+        return 0;
+}
+
+int dhcp6_lease_set_rapid_commit(sd_dhcp6_lease *lease) {
+        assert_return(lease, -EINVAL);
+
+        lease->rapid_commit = true;
+
+        return 0;
+}
+
+int dhcp6_lease_get_rapid_commit(sd_dhcp6_lease *lease, bool *rapid_commit) {
+        assert_return(lease, -EINVAL);
+        assert_return(rapid_commit, -EINVAL);
+
+        *rapid_commit = lease->rapid_commit;
+
+        return 0;
+}
+
+int dhcp6_lease_get_iaid(sd_dhcp6_lease *lease, be32_t *iaid) {
+        assert_return(lease, -EINVAL);
+        assert_return(iaid, -EINVAL);
+
+        *iaid = lease->ia.ia_na.id;
+
+        return 0;
+}
+
+int dhcp6_lease_get_pd_iaid(sd_dhcp6_lease *lease, be32_t *iaid) {
+        assert_return(lease, -EINVAL);
+        assert_return(iaid, -EINVAL);
+
+        *iaid = lease->pd.ia_pd.id;
+
+        return 0;
+}
+
+int sd_dhcp6_lease_get_address(sd_dhcp6_lease *lease, struct in6_addr *addr,
+                               uint32_t *lifetime_preferred,
+                               uint32_t *lifetime_valid) {
+        assert_return(lease, -EINVAL);
+        assert_return(addr, -EINVAL);
+        assert_return(lifetime_preferred, -EINVAL);
+        assert_return(lifetime_valid, -EINVAL);
+
+        if (!lease->addr_iter)
+                return -ENOMSG;
+
+        memcpy(addr, &lease->addr_iter->iaaddr.address,
+                sizeof(struct in6_addr));
+        *lifetime_preferred =
+                be32toh(lease->addr_iter->iaaddr.lifetime_preferred);
+        *lifetime_valid = be32toh(lease->addr_iter->iaaddr.lifetime_valid);
+
+        lease->addr_iter = lease->addr_iter->addresses_next;
+
+        return 0;
+}
+
+void sd_dhcp6_lease_reset_address_iter(sd_dhcp6_lease *lease) {
+        if (lease)
+                lease->addr_iter = lease->ia.addresses;
+}
+
+int sd_dhcp6_lease_get_pd(sd_dhcp6_lease *lease, struct in6_addr *prefix,
+                          uint8_t *prefix_len,
+                          uint32_t *lifetime_preferred,
+                          uint32_t *lifetime_valid) {
+        assert_return(lease, -EINVAL);
+        assert_return(prefix, -EINVAL);
+        assert_return(prefix_len, -EINVAL);
+        assert_return(lifetime_preferred, -EINVAL);
+        assert_return(lifetime_valid, -EINVAL);
+
+        if (!lease->prefix_iter)
+                return -ENOMSG;
+
+        memcpy(prefix, &lease->prefix_iter->iapdprefix.address,
+               sizeof(struct in6_addr));
+        *prefix_len = lease->prefix_iter->iapdprefix.prefixlen;
+        *lifetime_preferred =
+                be32toh(lease->prefix_iter->iapdprefix.lifetime_preferred);
+        *lifetime_valid =
+                be32toh(lease->prefix_iter->iapdprefix.lifetime_valid);
+
+        lease->prefix_iter = lease->prefix_iter->addresses_next;
+
+        return 0;
+}
+
+void sd_dhcp6_lease_reset_pd_prefix_iter(sd_dhcp6_lease *lease) {
+        if (lease)
+                lease->prefix_iter = lease->pd.addresses;
+}
+
+int dhcp6_lease_set_dns(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen) {
+        int r;
+
+        assert_return(lease, -EINVAL);
+        assert_return(optval, -EINVAL);
+
+        if (!optlen)
+                return 0;
+
+        r = dhcp6_option_parse_ip6addrs(optval, optlen, &lease->dns,
+                                        lease->dns_count,
+                                        &lease->dns_allocated);
+        if (r < 0)
+                return log_dhcp6_client_errno(client, r, "Invalid DNS server option: %m");
+
+        lease->dns_count = r;
+
+        return 0;
+}
+
+int sd_dhcp6_lease_get_dns(sd_dhcp6_lease *lease, const struct in6_addr **addrs) {
+        assert_return(lease, -EINVAL);
+        assert_return(addrs, -EINVAL);
+
+        if (lease->dns_count) {
+                *addrs = lease->dns;
+                return lease->dns_count;
+        }
+
+        return -ENOENT;
+}
+
+int dhcp6_lease_set_domains(sd_dhcp6_lease *lease, uint8_t *optval,
+                            size_t optlen) {
+        int r;
+        char **domains;
+
+        assert_return(lease, -EINVAL);
+        assert_return(optval, -EINVAL);
+
+        if (!optlen)
+                return 0;
+
+        r = dhcp6_option_parse_domainname_list(optval, optlen, &domains);
+        if (r < 0)
+                return 0;
+
+        strv_free_and_replace(lease->domains, domains);
+        lease->domains_count = r;
+
+        return r;
+}
+
+int sd_dhcp6_lease_get_domains(sd_dhcp6_lease *lease, char ***domains) {
+        assert_return(lease, -EINVAL);
+        assert_return(domains, -EINVAL);
+
+        if (lease->domains_count) {
+                *domains = lease->domains;
+                return lease->domains_count;
+        }
+
+        return -ENOENT;
+}
+
+int dhcp6_lease_set_ntp(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen) {
+        int r;
+        uint16_t subopt;
+        size_t sublen;
+        uint8_t *subval;
+
+        assert_return(lease, -EINVAL);
+        assert_return(optval, -EINVAL);
+
+        lease->ntp = mfree(lease->ntp);
+        lease->ntp_count = 0;
+        lease->ntp_allocated = 0;
+
+        while ((r = dhcp6_option_parse(&optval, &optlen, &subopt, &sublen,
+                                       &subval)) >= 0) {
+                int s;
+                char **servers;
+
+                switch(subopt) {
+                case DHCP6_NTP_SUBOPTION_SRV_ADDR:
+                case DHCP6_NTP_SUBOPTION_MC_ADDR:
+                        if (sublen != 16)
+                                return 0;
+
+                        s = dhcp6_option_parse_ip6addrs(subval, sublen,
+                                                        &lease->ntp,
+                                                        lease->ntp_count,
+                                                        &lease->ntp_allocated);
+                        if (s < 0)
+                                return s;
+
+                        lease->ntp_count = s;
+
+                        break;
+
+                case DHCP6_NTP_SUBOPTION_SRV_FQDN:
+                        r = dhcp6_option_parse_domainname_list(subval, sublen,
+                                                               &servers);
+                        if (r < 0)
+                                return 0;
+
+                        strv_free_and_replace(lease->ntp_fqdn, servers);
+                        lease->ntp_fqdn_count = r;
+
+                        break;
+                }
+        }
+
+        if (r != -ENOMSG)
+                return r;
+
+        return 0;
+}
+
+int dhcp6_lease_set_sntp(sd_dhcp6_lease *lease, uint8_t *optval, size_t optlen) {
+        int r;
+
+        assert_return(lease, -EINVAL);
+        assert_return(optval, -EINVAL);
+
+        if (!optlen)
+                return 0;
+
+        if (lease->ntp || lease->ntp_fqdn) {
+                log_dhcp6_client(client, "NTP information already provided");
+
+                return 0;
+        }
+
+        log_dhcp6_client(client, "Using deprecated SNTP information");
+
+        r = dhcp6_option_parse_ip6addrs(optval, optlen, &lease->ntp,
+                                        lease->ntp_count,
+                                        &lease->ntp_allocated);
+        if (r < 0)
+                return log_dhcp6_client_errno(client, r, "Invalid SNTP server option: %m");
+
+        lease->ntp_count = r;
+
+        return 0;
+}
+
+int sd_dhcp6_lease_get_ntp_addrs(sd_dhcp6_lease *lease,
+                                 const struct in6_addr **addrs) {
+        assert_return(lease, -EINVAL);
+        assert_return(addrs, -EINVAL);
+
+        if (lease->ntp_count) {
+                *addrs = lease->ntp;
+                return lease->ntp_count;
+        }
+
+        return -ENOENT;
+}
+
+int sd_dhcp6_lease_get_ntp_fqdn(sd_dhcp6_lease *lease, char ***ntp_fqdn) {
+        assert_return(lease, -EINVAL);
+        assert_return(ntp_fqdn, -EINVAL);
+
+        if (lease->ntp_fqdn_count) {
+                *ntp_fqdn = lease->ntp_fqdn;
+                return lease->ntp_fqdn_count;
+        }
+
+        return -ENOENT;
+}
+
+int dhcp6_lease_set_fqdn(sd_dhcp6_lease *lease, const uint8_t *optval,
+                         size_t optlen) {
+        int r;
+        char *fqdn;
+
+        assert_return(lease, -EINVAL);
+        assert_return(optval, -EINVAL);
+
+        if (optlen < 2)
+                return -ENODATA;
+
+        /* Ignore the flags field, it doesn't carry any useful
+           information for clients. */
+        r = dhcp6_option_parse_domainname(optval + 1, optlen - 1, &fqdn);
+        if (r < 0)
+                return r;
+
+        return free_and_replace(lease->fqdn, fqdn);
+}
+
+int sd_dhcp6_lease_get_fqdn(sd_dhcp6_lease *lease, const char **fqdn) {
+        assert_return(lease, -EINVAL);
+        assert_return(fqdn, -EINVAL);
+
+        if (lease->fqdn) {
+                *fqdn = lease->fqdn;
+                return 0;
+        }
+
+        return -ENOENT;
+}
+
+static sd_dhcp6_lease *dhcp6_lease_free(sd_dhcp6_lease *lease) {
+        assert(lease);
+
+        free(lease->serverid);
+        dhcp6_lease_free_ia(&lease->ia);
+        dhcp6_lease_free_ia(&lease->pd);
+
+        free(lease->dns);
+        free(lease->fqdn);
+
+        lease->domains = strv_free(lease->domains);
+
+        free(lease->ntp);
+
+        lease->ntp_fqdn = strv_free(lease->ntp_fqdn);
+        return mfree(lease);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp6_lease, sd_dhcp6_lease, dhcp6_lease_free);
+
+int dhcp6_lease_new(sd_dhcp6_lease **ret) {
+        sd_dhcp6_lease *lease;
+
+        lease = new0(sd_dhcp6_lease, 1);
+        if (!lease)
+                return -ENOMEM;
+
+        lease->n_ref = 1;
+
+        LIST_HEAD_INIT(lease->ia.addresses);
+
+        *ret = lease;
+        return 0;
+}
diff --git a/src/libsystemd-network/sd-ipv4acd.c b/src/libsystemd-network/sd-ipv4acd.c
new file mode 100644
index 0000000..2e1e46c
--- /dev/null
+++ b/src/libsystemd-network/sd-ipv4acd.c
@@ -0,0 +1,501 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Axis Communications AB. All rights reserved.
+***/
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netinet/if_ether.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sd-ipv4acd.h"
+
+#include "alloc-util.h"
+#include "arp-util.h"
+#include "ether-addr-util.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "in-addr-util.h"
+#include "list.h"
+#include "random-util.h"
+#include "siphash24.h"
+#include "string-util.h"
+#include "time-util.h"
+
+/* Constants from the RFC */
+#define PROBE_WAIT_USEC (1U * USEC_PER_SEC)
+#define PROBE_NUM 3U
+#define PROBE_MIN_USEC (1U * USEC_PER_SEC)
+#define PROBE_MAX_USEC (2U * USEC_PER_SEC)
+#define ANNOUNCE_WAIT_USEC (2U * USEC_PER_SEC)
+#define ANNOUNCE_NUM 2U
+#define ANNOUNCE_INTERVAL_USEC (2U * USEC_PER_SEC)
+#define MAX_CONFLICTS 10U
+#define RATE_LIMIT_INTERVAL_USEC (60U * USEC_PER_SEC)
+#define DEFEND_INTERVAL_USEC (10U * USEC_PER_SEC)
+
+typedef enum IPv4ACDState {
+        IPV4ACD_STATE_INIT,
+        IPV4ACD_STATE_STARTED,
+        IPV4ACD_STATE_WAITING_PROBE,
+        IPV4ACD_STATE_PROBING,
+        IPV4ACD_STATE_WAITING_ANNOUNCE,
+        IPV4ACD_STATE_ANNOUNCING,
+        IPV4ACD_STATE_RUNNING,
+        _IPV4ACD_STATE_MAX,
+        _IPV4ACD_STATE_INVALID = -1
+} IPv4ACDState;
+
+struct sd_ipv4acd {
+        unsigned n_ref;
+
+        IPv4ACDState state;
+        int ifindex;
+        int fd;
+
+        unsigned n_iteration;
+        unsigned n_conflict;
+
+        sd_event_source *receive_message_event_source;
+        sd_event_source *timer_event_source;
+
+        usec_t defend_window;
+        be32_t address;
+
+        /* External */
+        struct ether_addr mac_addr;
+
+        sd_event *event;
+        int event_priority;
+        sd_ipv4acd_callback_t callback;
+        void* userdata;
+};
+
+#define log_ipv4acd_errno(acd, error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "IPV4ACD: " fmt, ##__VA_ARGS__)
+#define log_ipv4acd(acd, fmt, ...) log_ipv4acd_errno(acd, 0, fmt, ##__VA_ARGS__)
+
+static void ipv4acd_set_state(sd_ipv4acd *acd, IPv4ACDState st, bool reset_counter) {
+        assert(acd);
+        assert(st < _IPV4ACD_STATE_MAX);
+
+        if (st == acd->state && !reset_counter)
+                acd->n_iteration++;
+        else {
+                acd->state = st;
+                acd->n_iteration = 0;
+        }
+}
+
+static void ipv4acd_reset(sd_ipv4acd *acd) {
+        assert(acd);
+
+        (void) event_source_disable(acd->timer_event_source);
+        acd->receive_message_event_source = sd_event_source_unref(acd->receive_message_event_source);
+
+        acd->fd = safe_close(acd->fd);
+
+        ipv4acd_set_state(acd, IPV4ACD_STATE_INIT, true);
+}
+
+static sd_ipv4acd *ipv4acd_free(sd_ipv4acd *acd) {
+        assert(acd);
+
+        acd->timer_event_source = sd_event_source_unref(acd->timer_event_source);
+
+        ipv4acd_reset(acd);
+        sd_ipv4acd_detach_event(acd);
+
+        return mfree(acd);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_ipv4acd, sd_ipv4acd, ipv4acd_free);
+
+int sd_ipv4acd_new(sd_ipv4acd **ret) {
+        _cleanup_(sd_ipv4acd_unrefp) sd_ipv4acd *acd = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        acd = new(sd_ipv4acd, 1);
+        if (!acd)
+                return -ENOMEM;
+
+        *acd = (sd_ipv4acd) {
+                .n_ref = 1,
+                .state = IPV4ACD_STATE_INIT,
+                .ifindex = -1,
+                .fd = -1,
+        };
+
+        *ret = TAKE_PTR(acd);
+
+        return 0;
+}
+
+static void ipv4acd_client_notify(sd_ipv4acd *acd, int event) {
+        assert(acd);
+
+        if (!acd->callback)
+                return;
+
+        acd->callback(acd, event, acd->userdata);
+}
+
+int sd_ipv4acd_stop(sd_ipv4acd *acd) {
+        IPv4ACDState old_state;
+
+        if (!acd)
+                return 0;
+
+        old_state = acd->state;
+
+        ipv4acd_reset(acd);
+
+        if (old_state == IPV4ACD_STATE_INIT)
+                return 0;
+
+        log_ipv4acd(acd, "STOPPED");
+
+        ipv4acd_client_notify(acd, SD_IPV4ACD_EVENT_STOP);
+
+        return 0;
+}
+
+static int ipv4acd_on_timeout(sd_event_source *s, uint64_t usec, void *userdata);
+
+static int ipv4acd_set_next_wakeup(sd_ipv4acd *acd, usec_t usec, usec_t random_usec) {
+        usec_t next_timeout, time_now;
+
+        assert(acd);
+
+        next_timeout = usec;
+
+        if (random_usec > 0)
+                next_timeout += (usec_t) random_u64() % random_usec;
+
+        assert_se(sd_event_now(acd->event, clock_boottime_or_monotonic(), &time_now) >= 0);
+
+        return event_reset_time(acd->event, &acd->timer_event_source,
+                                clock_boottime_or_monotonic(),
+                                time_now + next_timeout, 0,
+                                ipv4acd_on_timeout, acd,
+                                acd->event_priority, "ipv4acd-timer", true);
+}
+
+static bool ipv4acd_arp_conflict(sd_ipv4acd *acd, struct ether_arp *arp) {
+        assert(acd);
+        assert(arp);
+
+        /* see the BPF */
+        if (memcmp(arp->arp_spa, &acd->address, sizeof(acd->address)) == 0)
+                return true;
+
+        /* the TPA matched instead of the SPA, this is not a conflict */
+        return false;
+}
+
+static int ipv4acd_on_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_ipv4acd *acd = userdata;
+        int r = 0;
+
+        assert(acd);
+
+        switch (acd->state) {
+
+        case IPV4ACD_STATE_STARTED:
+                ipv4acd_set_state(acd, IPV4ACD_STATE_WAITING_PROBE, true);
+
+                if (acd->n_conflict >= MAX_CONFLICTS) {
+                        char ts[FORMAT_TIMESPAN_MAX];
+                        log_ipv4acd(acd, "Max conflicts reached, delaying by %s", format_timespan(ts, sizeof(ts), RATE_LIMIT_INTERVAL_USEC, 0));
+
+                        r = ipv4acd_set_next_wakeup(acd, RATE_LIMIT_INTERVAL_USEC, PROBE_WAIT_USEC);
+                        if (r < 0)
+                                goto fail;
+                } else {
+                        r = ipv4acd_set_next_wakeup(acd, 0, PROBE_WAIT_USEC);
+                        if (r < 0)
+                                goto fail;
+                }
+
+                break;
+
+        case IPV4ACD_STATE_WAITING_PROBE:
+        case IPV4ACD_STATE_PROBING:
+                /* Send a probe */
+                r = arp_send_probe(acd->fd, acd->ifindex, acd->address, &acd->mac_addr);
+                if (r < 0) {
+                        log_ipv4acd_errno(acd, r, "Failed to send ARP probe: %m");
+                        goto fail;
+                } else {
+                        _cleanup_free_ char *address = NULL;
+                        union in_addr_union addr = { .in.s_addr = acd->address };
+
+                        (void) in_addr_to_string(AF_INET, &addr, &address);
+                        log_ipv4acd(acd, "Probing %s", strna(address));
+                }
+
+                if (acd->n_iteration < PROBE_NUM - 2) {
+                        ipv4acd_set_state(acd, IPV4ACD_STATE_PROBING, false);
+
+                        r = ipv4acd_set_next_wakeup(acd, PROBE_MIN_USEC, (PROBE_MAX_USEC-PROBE_MIN_USEC));
+                        if (r < 0)
+                                goto fail;
+                } else {
+                        ipv4acd_set_state(acd, IPV4ACD_STATE_WAITING_ANNOUNCE, true);
+
+                        r = ipv4acd_set_next_wakeup(acd, ANNOUNCE_WAIT_USEC, 0);
+                        if (r < 0)
+                                goto fail;
+                }
+
+                break;
+
+        case IPV4ACD_STATE_ANNOUNCING:
+                if (acd->n_iteration >= ANNOUNCE_NUM - 1) {
+                        ipv4acd_set_state(acd, IPV4ACD_STATE_RUNNING, false);
+                        break;
+                }
+
+                _fallthrough_;
+        case IPV4ACD_STATE_WAITING_ANNOUNCE:
+                /* Send announcement packet */
+                r = arp_send_announcement(acd->fd, acd->ifindex, acd->address, &acd->mac_addr);
+                if (r < 0) {
+                        log_ipv4acd_errno(acd, r, "Failed to send ARP announcement: %m");
+                        goto fail;
+                } else
+                        log_ipv4acd(acd, "ANNOUNCE");
+
+                ipv4acd_set_state(acd, IPV4ACD_STATE_ANNOUNCING, false);
+
+                r = ipv4acd_set_next_wakeup(acd, ANNOUNCE_INTERVAL_USEC, 0);
+                if (r < 0)
+                        goto fail;
+
+                if (acd->n_iteration == 0) {
+                        acd->n_conflict = 0;
+                        ipv4acd_client_notify(acd, SD_IPV4ACD_EVENT_BIND);
+                }
+
+                break;
+
+        default:
+                assert_not_reached("Invalid state.");
+        }
+
+        return 0;
+
+fail:
+        sd_ipv4acd_stop(acd);
+        return 0;
+}
+
+static void ipv4acd_on_conflict(sd_ipv4acd *acd) {
+        _cleanup_free_ char *address = NULL;
+        union in_addr_union addr = { .in.s_addr = acd->address };
+
+        assert(acd);
+
+        acd->n_conflict++;
+
+        (void) in_addr_to_string(AF_INET, &addr, &address);
+        log_ipv4acd(acd, "Conflict on %s (%u)", strna(address), acd->n_conflict);
+
+        ipv4acd_reset(acd);
+        ipv4acd_client_notify(acd, SD_IPV4ACD_EVENT_CONFLICT);
+}
+
+static int ipv4acd_on_packet(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata) {
+
+        sd_ipv4acd *acd = userdata;
+        struct ether_arp packet;
+        ssize_t n;
+        int r;
+
+        assert(s);
+        assert(acd);
+        assert(fd >= 0);
+
+        n = recv(fd, &packet, sizeof(struct ether_arp), 0);
+        if (n < 0) {
+                if (IN_SET(errno, EAGAIN, EINTR))
+                        return 0;
+
+                log_ipv4acd_errno(acd, errno, "Failed to read ARP packet: %m");
+                goto fail;
+        }
+        if ((size_t) n != sizeof(struct ether_arp)) {
+                log_ipv4acd(acd, "Ignoring too short ARP packet.");
+                return 0;
+        }
+
+        switch (acd->state) {
+
+        case IPV4ACD_STATE_ANNOUNCING:
+        case IPV4ACD_STATE_RUNNING:
+
+                if (ipv4acd_arp_conflict(acd, &packet)) {
+                        usec_t ts;
+
+                        assert_se(sd_event_now(acd->event, clock_boottime_or_monotonic(), &ts) >= 0);
+
+                        /* Defend address */
+                        if (ts > acd->defend_window) {
+                                acd->defend_window = ts + DEFEND_INTERVAL_USEC;
+                                r = arp_send_announcement(acd->fd, acd->ifindex, acd->address, &acd->mac_addr);
+                                if (r < 0) {
+                                        log_ipv4acd_errno(acd, r, "Failed to send ARP announcement: %m");
+                                        goto fail;
+                                } else
+                                        log_ipv4acd(acd, "DEFEND");
+
+                        } else
+                                ipv4acd_on_conflict(acd);
+                }
+                break;
+
+        case IPV4ACD_STATE_WAITING_PROBE:
+        case IPV4ACD_STATE_PROBING:
+        case IPV4ACD_STATE_WAITING_ANNOUNCE:
+                /* BPF ensures this packet indicates a conflict */
+                ipv4acd_on_conflict(acd);
+                break;
+
+        default:
+                assert_not_reached("Invalid state.");
+        }
+
+        return 0;
+
+fail:
+        sd_ipv4acd_stop(acd);
+        return 0;
+}
+
+int sd_ipv4acd_set_ifindex(sd_ipv4acd *acd, int ifindex) {
+        assert_return(acd, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(acd->state == IPV4ACD_STATE_INIT, -EBUSY);
+
+        acd->ifindex = ifindex;
+
+        return 0;
+}
+
+int sd_ipv4acd_set_mac(sd_ipv4acd *acd, const struct ether_addr *addr) {
+        assert_return(acd, -EINVAL);
+        assert_return(addr, -EINVAL);
+        assert_return(acd->state == IPV4ACD_STATE_INIT, -EBUSY);
+
+        acd->mac_addr = *addr;
+
+        return 0;
+}
+
+int sd_ipv4acd_detach_event(sd_ipv4acd *acd) {
+        assert_return(acd, -EINVAL);
+
+        acd->event = sd_event_unref(acd->event);
+
+        return 0;
+}
+
+int sd_ipv4acd_attach_event(sd_ipv4acd *acd, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+        assert_return(!acd->event, -EBUSY);
+
+        if (event)
+                acd->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&acd->event);
+                if (r < 0)
+                        return r;
+        }
+
+        acd->event_priority = priority;
+
+        return 0;
+}
+
+int sd_ipv4acd_set_callback(sd_ipv4acd *acd, sd_ipv4acd_callback_t cb, void *userdata) {
+        assert_return(acd, -EINVAL);
+
+        acd->callback = cb;
+        acd->userdata = userdata;
+
+        return 0;
+}
+
+int sd_ipv4acd_set_address(sd_ipv4acd *acd, const struct in_addr *address) {
+        assert_return(acd, -EINVAL);
+        assert_return(address, -EINVAL);
+        assert_return(acd->state == IPV4ACD_STATE_INIT, -EBUSY);
+
+        acd->address = address->s_addr;
+
+        return 0;
+}
+
+int sd_ipv4acd_get_address(sd_ipv4acd *acd, struct in_addr *address) {
+        assert_return(acd, -EINVAL);
+        assert_return(address, -EINVAL);
+
+        address->s_addr = acd->address;
+
+        return 0;
+}
+
+int sd_ipv4acd_is_running(sd_ipv4acd *acd) {
+        assert_return(acd, false);
+
+        return acd->state != IPV4ACD_STATE_INIT;
+}
+
+int sd_ipv4acd_start(sd_ipv4acd *acd, bool reset_conflicts) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+        assert_return(acd->event, -EINVAL);
+        assert_return(acd->ifindex > 0, -EINVAL);
+        assert_return(acd->address != 0, -EINVAL);
+        assert_return(!ether_addr_is_null(&acd->mac_addr), -EINVAL);
+        assert_return(acd->state == IPV4ACD_STATE_INIT, -EBUSY);
+
+        r = arp_network_bind_raw_socket(acd->ifindex, acd->address, &acd->mac_addr);
+        if (r < 0)
+                return r;
+
+        CLOSE_AND_REPLACE(acd->fd, r);
+        acd->defend_window = 0;
+
+        if (reset_conflicts)
+                acd->n_conflict = 0;
+
+        r = sd_event_add_io(acd->event, &acd->receive_message_event_source, acd->fd, EPOLLIN, ipv4acd_on_packet, acd);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(acd->receive_message_event_source, acd->event_priority);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(acd->receive_message_event_source, "ipv4acd-receive-message");
+
+        r = ipv4acd_set_next_wakeup(acd, 0, 0);
+        if (r < 0)
+                goto fail;
+
+        ipv4acd_set_state(acd, IPV4ACD_STATE_STARTED, true);
+        return 0;
+
+fail:
+        ipv4acd_reset(acd);
+        return r;
+}
diff --git a/src/libsystemd-network/sd-ipv4ll.c b/src/libsystemd-network/sd-ipv4ll.c
new file mode 100644
index 0000000..09f2bda
--- /dev/null
+++ b/src/libsystemd-network/sd-ipv4ll.c
@@ -0,0 +1,324 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Axis Communications AB. All rights reserved.
+***/
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sd-id128.h"
+#include "sd-ipv4acd.h"
+#include "sd-ipv4ll.h"
+
+#include "alloc-util.h"
+#include "ether-addr-util.h"
+#include "in-addr-util.h"
+#include "list.h"
+#include "random-util.h"
+#include "siphash24.h"
+#include "sparse-endian.h"
+#include "string-util.h"
+#include "util.h"
+
+#define IPV4LL_NETWORK UINT32_C(0xA9FE0000)
+#define IPV4LL_NETMASK UINT32_C(0xFFFF0000)
+
+#define IPV4LL_DONT_DESTROY(ll) \
+        _cleanup_(sd_ipv4ll_unrefp) _unused_ sd_ipv4ll *_dont_destroy_##ll = sd_ipv4ll_ref(ll)
+
+struct sd_ipv4ll {
+        unsigned n_ref;
+
+        sd_ipv4acd *acd;
+
+        be32_t address; /* the address pushed to ACD */
+        struct ether_addr mac;
+
+        struct {
+                le64_t value;
+                le64_t generation;
+        } seed;
+        bool seed_set;
+
+        /* External */
+        be32_t claimed_address;
+
+        sd_ipv4ll_callback_t callback;
+        void* userdata;
+};
+
+#define log_ipv4ll_errno(ll, error, fmt, ...) log_internal(LOG_DEBUG, error, PROJECT_FILE, __LINE__, __func__, "IPV4LL: " fmt, ##__VA_ARGS__)
+#define log_ipv4ll(ll, fmt, ...) log_ipv4ll_errno(ll, 0, fmt, ##__VA_ARGS__)
+
+static void ipv4ll_on_acd(sd_ipv4acd *ll, int event, void *userdata);
+
+static sd_ipv4ll *ipv4ll_free(sd_ipv4ll *ll) {
+        assert(ll);
+
+        sd_ipv4acd_unref(ll->acd);
+        return mfree(ll);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_ipv4ll, sd_ipv4ll, ipv4ll_free);
+
+int sd_ipv4ll_new(sd_ipv4ll **ret) {
+        _cleanup_(sd_ipv4ll_unrefp) sd_ipv4ll *ll = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        ll = new0(sd_ipv4ll, 1);
+        if (!ll)
+                return -ENOMEM;
+
+        ll->n_ref = 1;
+
+        r = sd_ipv4acd_new(&ll->acd);
+        if (r < 0)
+                return r;
+
+        r = sd_ipv4acd_set_callback(ll->acd, ipv4ll_on_acd, ll);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(ll);
+
+        return 0;
+}
+
+int sd_ipv4ll_stop(sd_ipv4ll *ll) {
+        if (!ll)
+                return 0;
+
+        return sd_ipv4acd_stop(ll->acd);
+}
+
+int sd_ipv4ll_set_ifindex(sd_ipv4ll *ll, int ifindex) {
+        assert_return(ll, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(sd_ipv4ll_is_running(ll) == 0, -EBUSY);
+
+        return sd_ipv4acd_set_ifindex(ll->acd, ifindex);
+}
+
+int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
+        int r;
+
+        assert_return(ll, -EINVAL);
+        assert_return(addr, -EINVAL);
+        assert_return(sd_ipv4ll_is_running(ll) == 0, -EBUSY);
+
+        r = sd_ipv4acd_set_mac(ll->acd, addr);
+        if (r < 0)
+                return r;
+
+        ll->mac = *addr;
+        return 0;
+}
+
+int sd_ipv4ll_detach_event(sd_ipv4ll *ll) {
+        assert_return(ll, -EINVAL);
+
+        return sd_ipv4acd_detach_event(ll->acd);
+}
+
+int sd_ipv4ll_attach_event(sd_ipv4ll *ll, sd_event *event, int64_t priority) {
+        assert_return(ll, -EINVAL);
+
+        return sd_ipv4acd_attach_event(ll->acd, event, priority);
+}
+
+int sd_ipv4ll_set_callback(sd_ipv4ll *ll, sd_ipv4ll_callback_t cb, void *userdata) {
+        assert_return(ll, -EINVAL);
+
+        ll->callback = cb;
+        ll->userdata = userdata;
+
+        return 0;
+}
+
+int sd_ipv4ll_get_address(sd_ipv4ll *ll, struct in_addr *address) {
+        assert_return(ll, -EINVAL);
+        assert_return(address, -EINVAL);
+
+        if (ll->claimed_address == 0)
+                return -ENOENT;
+
+        address->s_addr = ll->claimed_address;
+
+        return 0;
+}
+
+int sd_ipv4ll_set_address_seed(sd_ipv4ll *ll, uint64_t seed) {
+        assert_return(ll, -EINVAL);
+        assert_return(sd_ipv4ll_is_running(ll) == 0, -EBUSY);
+
+        ll->seed.value = htole64(seed);
+        ll->seed_set = true;
+
+        return 0;
+}
+
+int sd_ipv4ll_is_running(sd_ipv4ll *ll) {
+        assert_return(ll, false);
+
+        return sd_ipv4acd_is_running(ll->acd);
+}
+
+static bool ipv4ll_address_is_valid(const struct in_addr *address) {
+        assert(address);
+
+        if (!in_addr_is_link_local(AF_INET, (const union in_addr_union *) address))
+                return false;
+
+        return !IN_SET(be32toh(address->s_addr) & 0x0000FF00U, 0x0000U, 0xFF00U);
+}
+
+int sd_ipv4ll_set_address(sd_ipv4ll *ll, const struct in_addr *address) {
+        int r;
+
+        assert_return(ll, -EINVAL);
+        assert_return(address, -EINVAL);
+        assert_return(ipv4ll_address_is_valid(address), -EINVAL);
+
+        r = sd_ipv4acd_set_address(ll->acd, address);
+        if (r < 0)
+                return r;
+
+        ll->address = address->s_addr;
+
+        return 0;
+}
+
+#define PICK_HASH_KEY SD_ID128_MAKE(15,ac,82,a6,d6,3f,49,78,98,77,5d,0c,69,02,94,0b)
+
+static int ipv4ll_pick_address(sd_ipv4ll *ll) {
+        _cleanup_free_ char *address = NULL;
+        be32_t addr;
+
+        assert(ll);
+
+        do {
+                uint64_t h;
+
+                h = siphash24(&ll->seed, sizeof(ll->seed), PICK_HASH_KEY.bytes);
+
+                /* Increase the generation counter by one */
+                ll->seed.generation = htole64(le64toh(ll->seed.generation) + 1);
+
+                addr = htobe32((h & UINT32_C(0x0000FFFF)) | IPV4LL_NETWORK);
+        } while (addr == ll->address ||
+                 IN_SET(be32toh(addr) & 0x0000FF00U, 0x0000U, 0xFF00U));
+
+        (void) in_addr_to_string(AF_INET, &(union in_addr_union) { .in.s_addr = addr }, &address);
+        log_ipv4ll(ll, "Picked new IP address %s.", strna(address));
+
+        return sd_ipv4ll_set_address(ll, &(struct in_addr) { addr });
+}
+
+#define MAC_HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2)
+
+static int ipv4ll_start_internal(sd_ipv4ll *ll, bool reset_generation) {
+        int r;
+        bool picked_address = false;
+
+        assert_return(ll, -EINVAL);
+        assert_return(!ether_addr_is_null(&ll->mac), -EINVAL);
+
+        /* If no random seed is set, generate some from the MAC address */
+        if (!ll->seed_set)
+                ll->seed.value = htole64(siphash24(ll->mac.ether_addr_octet, ETH_ALEN, MAC_HASH_KEY.bytes));
+
+        if (reset_generation)
+                ll->seed.generation = 0;
+
+        if (ll->address == 0) {
+                r = ipv4ll_pick_address(ll);
+                if (r < 0)
+                        return r;
+
+                picked_address = true;
+        }
+
+        r = sd_ipv4acd_start(ll->acd, reset_generation);
+        if (r < 0) {
+
+                /* We couldn't start? If so, let's forget the picked address again, the user might make a change and
+                 * retry, and we want the new data to take effect when picking an address. */
+                if (picked_address)
+                        ll->address = 0;
+
+                return r;
+        }
+
+        return 1;
+}
+
+int sd_ipv4ll_start(sd_ipv4ll *ll) {
+        assert_return(ll, -EINVAL);
+
+        if (sd_ipv4ll_is_running(ll))
+                return 0;
+
+        return ipv4ll_start_internal(ll, true);
+}
+
+int sd_ipv4ll_restart(sd_ipv4ll *ll) {
+        ll->address = 0;
+
+        return ipv4ll_start_internal(ll, false);
+}
+
+static void ipv4ll_client_notify(sd_ipv4ll *ll, int event) {
+        assert(ll);
+
+        if (ll->callback)
+                ll->callback(ll, event, ll->userdata);
+}
+
+void ipv4ll_on_acd(sd_ipv4acd *acd, int event, void *userdata) {
+        sd_ipv4ll *ll = userdata;
+        IPV4LL_DONT_DESTROY(ll);
+        int r;
+
+        assert(acd);
+        assert(ll);
+
+        switch (event) {
+
+        case SD_IPV4ACD_EVENT_STOP:
+                ipv4ll_client_notify(ll, SD_IPV4LL_EVENT_STOP);
+                ll->claimed_address = 0;
+                break;
+
+        case SD_IPV4ACD_EVENT_BIND:
+                ll->claimed_address = ll->address;
+                ipv4ll_client_notify(ll, SD_IPV4LL_EVENT_BIND);
+                break;
+
+        case SD_IPV4ACD_EVENT_CONFLICT:
+                /* if an address was already bound we must call up to the
+                   user to handle this, otherwise we just try again */
+                if (ll->claimed_address != 0) {
+                        ipv4ll_client_notify(ll, SD_IPV4LL_EVENT_CONFLICT);
+
+                        ll->claimed_address = 0;
+                } else {
+                        r = sd_ipv4ll_restart(ll);
+                        if (r < 0)
+                                goto error;
+                }
+
+                break;
+
+        default:
+                assert_not_reached("Invalid IPv4ACD event.");
+        }
+
+        return;
+
+error:
+        ipv4ll_client_notify(ll, SD_IPV4LL_EVENT_STOP);
+}
diff --git a/src/libsystemd-network/sd-lldp.c b/src/libsystemd-network/sd-lldp.c
new file mode 100644
index 0000000..8b66652
--- /dev/null
+++ b/src/libsystemd-network/sd-lldp.c
@@ -0,0 +1,498 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <arpa/inet.h>
+#include <linux/sockios.h>
+#include <sys/ioctl.h>
+
+#include "sd-lldp.h"
+
+#include "alloc-util.h"
+#include "ether-addr-util.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "lldp-internal.h"
+#include "lldp-neighbor.h"
+#include "lldp-network.h"
+#include "memory-util.h"
+#include "socket-util.h"
+#include "sort-util.h"
+#include "string-table.h"
+
+#define LLDP_DEFAULT_NEIGHBORS_MAX 128U
+
+static const char * const lldp_event_table[_SD_LLDP_EVENT_MAX] = {
+        [SD_LLDP_EVENT_ADDED]   = "added",
+        [SD_LLDP_EVENT_REMOVED] = "removed",
+        [SD_LLDP_EVENT_UPDATED]   = "updated",
+        [SD_LLDP_EVENT_REFRESHED] = "refreshed",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(lldp_event, sd_lldp_event);
+
+static void lldp_flush_neighbors(sd_lldp *lldp) {
+        assert(lldp);
+
+        hashmap_clear(lldp->neighbor_by_id);
+}
+
+static void lldp_callback(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n) {
+        assert(lldp);
+        assert(event >= 0 && event < _SD_LLDP_EVENT_MAX);
+
+        if (!lldp->callback) {
+                log_lldp("Received '%s' event.", lldp_event_to_string(event));
+                return;
+        }
+
+        log_lldp("Invoking callback for '%s' event.", lldp_event_to_string(event));
+        lldp->callback(lldp, event, n, lldp->userdata);
+}
+
+static int lldp_make_space(sd_lldp *lldp, size_t extra) {
+        usec_t t = USEC_INFINITY;
+        bool changed = false;
+
+        assert(lldp);
+
+        /* Remove all entries that are past their TTL, and more until at least the specified number of extra entries
+         * are free. */
+
+        for (;;) {
+                _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
+
+                n = prioq_peek(lldp->neighbor_by_expiry);
+                if (!n)
+                        break;
+
+                sd_lldp_neighbor_ref(n);
+
+                if (hashmap_size(lldp->neighbor_by_id) > LESS_BY(lldp->neighbors_max, extra))
+                        goto remove_one;
+
+                if (t == USEC_INFINITY)
+                        t = now(clock_boottime_or_monotonic());
+
+                if (n->until > t)
+                        break;
+
+        remove_one:
+                lldp_neighbor_unlink(n);
+                lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, n);
+                changed = true;
+        }
+
+        return changed;
+}
+
+static bool lldp_keep_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) {
+        assert(lldp);
+        assert(n);
+
+        /* Don't keep data with a zero TTL */
+        if (n->ttl <= 0)
+                return false;
+
+        /* Filter out data from the filter address */
+        if (!ether_addr_is_null(&lldp->filter_address) &&
+            ether_addr_equal(&lldp->filter_address, &n->source_address))
+                return false;
+
+        /* Only add if the neighbor has a capability we are interested in. Note that we also store all neighbors with
+         * no caps field set. */
+        if (n->has_capabilities &&
+            (n->enabled_capabilities & lldp->capability_mask) == 0)
+                return false;
+
+        /* Keep everything else */
+        return true;
+}
+
+static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor);
+
+static int lldp_add_neighbor(sd_lldp *lldp, sd_lldp_neighbor *n) {
+        _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *old = NULL;
+        bool keep;
+        int r;
+
+        assert(lldp);
+        assert(n);
+        assert(!n->lldp);
+
+        keep = lldp_keep_neighbor(lldp, n);
+
+        /* First retrieve the old entry for this MSAP */
+        old = hashmap_get(lldp->neighbor_by_id, &n->id);
+        if (old) {
+                sd_lldp_neighbor_ref(old);
+
+                if (!keep) {
+                        lldp_neighbor_unlink(old);
+                        lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, old);
+                        return 0;
+                }
+
+                if (lldp_neighbor_equal(n, old)) {
+                        /* Is this equal, then restart the TTL counter, but don't do anything else. */
+                        old->timestamp = n->timestamp;
+                        lldp_start_timer(lldp, old);
+                        lldp_callback(lldp, SD_LLDP_EVENT_REFRESHED, old);
+                        return 0;
+                }
+
+                /* Data changed, remove the old entry, and add a new one */
+                lldp_neighbor_unlink(old);
+
+        } else if (!keep)
+                return 0;
+
+        /* Then, make room for at least one new neighbor */
+        lldp_make_space(lldp, 1);
+
+        r = hashmap_put(lldp->neighbor_by_id, &n->id, n);
+        if (r < 0)
+                goto finish;
+
+        r = prioq_put(lldp->neighbor_by_expiry, n, &n->prioq_idx);
+        if (r < 0) {
+                assert_se(hashmap_remove(lldp->neighbor_by_id, &n->id) == n);
+                goto finish;
+        }
+
+        n->lldp = lldp;
+
+        lldp_start_timer(lldp, n);
+        lldp_callback(lldp, old ? SD_LLDP_EVENT_UPDATED : SD_LLDP_EVENT_ADDED, n);
+
+        return 1;
+
+finish:
+        if (old)
+                lldp_callback(lldp, SD_LLDP_EVENT_REMOVED, old);
+
+        return r;
+}
+
+static int lldp_handle_datagram(sd_lldp *lldp, sd_lldp_neighbor *n) {
+        int r;
+
+        assert(lldp);
+        assert(n);
+
+        r = lldp_neighbor_parse(n);
+        if (r == -EBADMSG) /* Ignore bad messages */
+                return 0;
+        if (r < 0)
+                return r;
+
+        r = lldp_add_neighbor(lldp, n);
+        if (r < 0) {
+                log_lldp_errno(r, "Failed to add datagram. Ignoring.");
+                return 0;
+        }
+
+        log_lldp("Successfully processed LLDP datagram.");
+        return 0;
+}
+
+static int lldp_receive_datagram(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        _cleanup_(sd_lldp_neighbor_unrefp) sd_lldp_neighbor *n = NULL;
+        ssize_t space, length;
+        sd_lldp *lldp = userdata;
+        struct timespec ts;
+
+        assert(fd >= 0);
+        assert(lldp);
+
+        space = next_datagram_size_fd(fd);
+        if (space < 0)
+                return log_lldp_errno(space, "Failed to determine datagram size to read: %m");
+
+        n = lldp_neighbor_new(space);
+        if (!n)
+                return -ENOMEM;
+
+        length = recv(fd, LLDP_NEIGHBOR_RAW(n), n->raw_size, MSG_DONTWAIT);
+        if (length < 0) {
+                if (IN_SET(errno, EAGAIN, EINTR))
+                        return 0;
+
+                return log_lldp_errno(errno, "Failed to read LLDP datagram: %m");
+        }
+
+        if ((size_t) length != n->raw_size) {
+                log_lldp("Packet size mismatch.");
+                return -EINVAL;
+        }
+
+        /* Try to get the timestamp of this packet if it is known */
+        if (ioctl(fd, SIOCGSTAMPNS, &ts) >= 0)
+                triple_timestamp_from_realtime(&n->timestamp, timespec_load(&ts));
+        else
+                triple_timestamp_get(&n->timestamp);
+
+        return lldp_handle_datagram(lldp, n);
+}
+
+static void lldp_reset(sd_lldp *lldp) {
+        assert(lldp);
+
+        (void) event_source_disable(lldp->timer_event_source);
+        lldp->io_event_source = sd_event_source_unref(lldp->io_event_source);
+        lldp->fd = safe_close(lldp->fd);
+}
+
+_public_ int sd_lldp_start(sd_lldp *lldp) {
+        int r;
+
+        assert_return(lldp, -EINVAL);
+        assert_return(lldp->event, -EINVAL);
+        assert_return(lldp->ifindex > 0, -EINVAL);
+
+        if (lldp->fd >= 0)
+                return 0;
+
+        assert(!lldp->io_event_source);
+
+        lldp->fd = lldp_network_bind_raw_socket(lldp->ifindex);
+        if (lldp->fd < 0)
+                return lldp->fd;
+
+        r = sd_event_add_io(lldp->event, &lldp->io_event_source, lldp->fd, EPOLLIN, lldp_receive_datagram, lldp);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(lldp->io_event_source, lldp->event_priority);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(lldp->io_event_source, "lldp-io");
+
+        log_lldp("Started LLDP client");
+        return 1;
+
+fail:
+        lldp_reset(lldp);
+        return r;
+}
+
+_public_ int sd_lldp_stop(sd_lldp *lldp) {
+        if (!lldp)
+                return 0;
+
+        if (lldp->fd < 0)
+                return 0;
+
+        log_lldp("Stopping LLDP client");
+
+        lldp_reset(lldp);
+        lldp_flush_neighbors(lldp);
+
+        return 1;
+}
+
+_public_ int sd_lldp_attach_event(sd_lldp *lldp, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(lldp, -EINVAL);
+        assert_return(lldp->fd < 0, -EBUSY);
+        assert_return(!lldp->event, -EBUSY);
+
+        if (event)
+                lldp->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&lldp->event);
+                if (r < 0)
+                        return r;
+        }
+
+        lldp->event_priority = priority;
+
+        return 0;
+}
+
+_public_ int sd_lldp_detach_event(sd_lldp *lldp) {
+
+        assert_return(lldp, -EINVAL);
+        assert_return(lldp->fd < 0, -EBUSY);
+
+        lldp->event = sd_event_unref(lldp->event);
+        return 0;
+}
+
+_public_ sd_event* sd_lldp_get_event(sd_lldp *lldp) {
+        assert_return(lldp, NULL);
+
+        return lldp->event;
+}
+
+_public_ int sd_lldp_set_callback(sd_lldp *lldp, sd_lldp_callback_t cb, void *userdata) {
+        assert_return(lldp, -EINVAL);
+
+        lldp->callback = cb;
+        lldp->userdata = userdata;
+
+        return 0;
+}
+
+_public_ int sd_lldp_set_ifindex(sd_lldp *lldp, int ifindex) {
+        assert_return(lldp, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(lldp->fd < 0, -EBUSY);
+
+        lldp->ifindex = ifindex;
+        return 0;
+}
+
+static sd_lldp* lldp_free(sd_lldp *lldp) {
+        assert(lldp);
+
+        lldp->timer_event_source = sd_event_source_unref(lldp->timer_event_source);
+
+        lldp_reset(lldp);
+        sd_lldp_detach_event(lldp);
+        lldp_flush_neighbors(lldp);
+
+        hashmap_free(lldp->neighbor_by_id);
+        prioq_free(lldp->neighbor_by_expiry);
+        return mfree(lldp);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_lldp, sd_lldp, lldp_free);
+
+_public_ int sd_lldp_new(sd_lldp **ret) {
+        _cleanup_(sd_lldp_unrefp) sd_lldp *lldp = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        lldp = new(sd_lldp, 1);
+        if (!lldp)
+                return -ENOMEM;
+
+        *lldp = (sd_lldp) {
+                .n_ref = 1,
+                .fd = -1,
+                .neighbors_max = LLDP_DEFAULT_NEIGHBORS_MAX,
+                .capability_mask = (uint16_t) -1,
+        };
+
+        lldp->neighbor_by_id = hashmap_new(&lldp_neighbor_hash_ops);
+        if (!lldp->neighbor_by_id)
+                return -ENOMEM;
+
+        r = prioq_ensure_allocated(&lldp->neighbor_by_expiry, lldp_neighbor_prioq_compare_func);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(lldp);
+
+        return 0;
+}
+
+static int neighbor_compare_func(sd_lldp_neighbor * const *a, sd_lldp_neighbor * const *b) {
+        return lldp_neighbor_id_compare_func(&(*a)->id, &(*b)->id);
+}
+
+static int on_timer_event(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_lldp *lldp = userdata;
+        int r;
+
+        r = lldp_make_space(lldp, 0);
+        if (r < 0)
+                return log_lldp_errno(r, "Failed to make space: %m");
+
+        r = lldp_start_timer(lldp, NULL);
+        if (r < 0)
+                return log_lldp_errno(r, "Failed to restart timer: %m");
+
+        return 0;
+}
+
+static int lldp_start_timer(sd_lldp *lldp, sd_lldp_neighbor *neighbor) {
+        sd_lldp_neighbor *n;
+
+        assert(lldp);
+
+        if (neighbor)
+                lldp_neighbor_start_ttl(neighbor);
+
+        n = prioq_peek(lldp->neighbor_by_expiry);
+        if (!n)
+                return event_source_disable(lldp->timer_event_source);
+
+        if (!lldp->event)
+                return 0;
+
+        return event_reset_time(lldp->event, &lldp->timer_event_source,
+                                clock_boottime_or_monotonic(),
+                                n->until, 0,
+                                on_timer_event, lldp,
+                                lldp->event_priority, "lldp-timer", true);
+}
+
+_public_ int sd_lldp_get_neighbors(sd_lldp *lldp, sd_lldp_neighbor ***ret) {
+        sd_lldp_neighbor **l = NULL, *n;
+        int k = 0, r;
+
+        assert_return(lldp, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (hashmap_isempty(lldp->neighbor_by_id)) { /* Special shortcut */
+                *ret = NULL;
+                return 0;
+        }
+
+        l = new0(sd_lldp_neighbor*, hashmap_size(lldp->neighbor_by_id));
+        if (!l)
+                return -ENOMEM;
+
+        r = lldp_start_timer(lldp, NULL);
+        if (r < 0) {
+                free(l);
+                return r;
+        }
+
+        HASHMAP_FOREACH(n, lldp->neighbor_by_id)
+                l[k++] = sd_lldp_neighbor_ref(n);
+
+        assert((size_t) k == hashmap_size(lldp->neighbor_by_id));
+
+        /* Return things in a stable order */
+        typesafe_qsort(l, k, neighbor_compare_func);
+        *ret = l;
+
+        return k;
+}
+
+_public_ int sd_lldp_set_neighbors_max(sd_lldp *lldp, uint64_t m) {
+        assert_return(lldp, -EINVAL);
+        assert_return(m > 0, -EINVAL);
+
+        lldp->neighbors_max = m;
+        lldp_make_space(lldp, 0);
+
+        return 0;
+}
+
+_public_ int sd_lldp_match_capabilities(sd_lldp *lldp, uint16_t mask) {
+        assert_return(lldp, -EINVAL);
+        assert_return(mask != 0, -EINVAL);
+
+        lldp->capability_mask = mask;
+
+        return 0;
+}
+
+_public_ int sd_lldp_set_filter_address(sd_lldp *lldp, const struct ether_addr *addr) {
+        assert_return(lldp, -EINVAL);
+
+        /* In order to deal nicely with bridges that send back our own packets, allow one address to be filtered, so
+         * that our own can be filtered out here. */
+
+        if (addr)
+                lldp->filter_address = *addr;
+        else
+                zero(lldp->filter_address);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/sd-ndisc.c b/src/libsystemd-network/sd-ndisc.c
new file mode 100644
index 0000000..db7ada6
--- /dev/null
+++ b/src/libsystemd-network/sd-ndisc.c
@@ -0,0 +1,389 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/icmp6.h>
+#include <netinet/in.h>
+
+#include "sd-ndisc.h"
+
+#include "alloc-util.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "icmp6-util.h"
+#include "in-addr-util.h"
+#include "memory-util.h"
+#include "ndisc-internal.h"
+#include "ndisc-router.h"
+#include "random-util.h"
+#include "socket-util.h"
+#include "string-table.h"
+#include "string-util.h"
+
+#define NDISC_TIMEOUT_NO_RA_USEC (NDISC_ROUTER_SOLICITATION_INTERVAL * NDISC_MAX_ROUTER_SOLICITATIONS)
+
+static const char * const ndisc_event_table[_SD_NDISC_EVENT_MAX] = {
+        [SD_NDISC_EVENT_TIMEOUT] = "timeout",
+        [SD_NDISC_EVENT_ROUTER] = "router",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event);
+
+static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event event, sd_ndisc_router *rt) {
+        assert(ndisc);
+        assert(event >= 0 && event < _SD_NDISC_EVENT_MAX);
+
+        if (!ndisc->callback) {
+                log_ndisc("Received '%s' event.", ndisc_event_to_string(event));
+                return;
+        }
+
+        log_ndisc("Invoking callback for '%s' event.", ndisc_event_to_string(event));
+        ndisc->callback(ndisc, event, rt, ndisc->userdata);
+}
+
+_public_ int sd_ndisc_set_callback(
+                sd_ndisc *nd,
+                sd_ndisc_callback_t callback,
+                void *userdata) {
+
+        assert_return(nd, -EINVAL);
+
+        nd->callback = callback;
+        nd->userdata = userdata;
+
+        return 0;
+}
+
+_public_ int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) {
+        assert_return(nd, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(nd->fd < 0, -EBUSY);
+
+        nd->ifindex = ifindex;
+        return 0;
+}
+
+_public_ int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) {
+        assert_return(nd, -EINVAL);
+
+        if (mac_addr)
+                nd->mac_addr = *mac_addr;
+        else
+                zero(nd->mac_addr);
+
+        return 0;
+}
+
+_public_ int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(nd, -EINVAL);
+        assert_return(nd->fd < 0, -EBUSY);
+        assert_return(!nd->event, -EBUSY);
+
+        if (event)
+                nd->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&nd->event);
+                if (r < 0)
+                        return 0;
+        }
+
+        nd->event_priority = priority;
+
+        return 0;
+}
+
+_public_ int sd_ndisc_detach_event(sd_ndisc *nd) {
+
+        assert_return(nd, -EINVAL);
+        assert_return(nd->fd < 0, -EBUSY);
+
+        nd->event = sd_event_unref(nd->event);
+        return 0;
+}
+
+_public_ sd_event *sd_ndisc_get_event(sd_ndisc *nd) {
+        assert_return(nd, NULL);
+
+        return nd->event;
+}
+
+static void ndisc_reset(sd_ndisc *nd) {
+        assert(nd);
+
+        (void) event_source_disable(nd->timeout_event_source);
+        (void) event_source_disable(nd->timeout_no_ra);
+        nd->retransmit_time = 0;
+        nd->recv_event_source = sd_event_source_unref(nd->recv_event_source);
+        nd->fd = safe_close(nd->fd);
+}
+
+static sd_ndisc *ndisc_free(sd_ndisc *nd) {
+        assert(nd);
+
+        nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source);
+        nd->timeout_no_ra = sd_event_source_unref(nd->timeout_no_ra);
+
+        ndisc_reset(nd);
+        sd_ndisc_detach_event(nd);
+        return mfree(nd);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc, sd_ndisc, ndisc_free);
+
+_public_ int sd_ndisc_new(sd_ndisc **ret) {
+        _cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        nd = new(sd_ndisc, 1);
+        if (!nd)
+                return -ENOMEM;
+
+        *nd = (sd_ndisc) {
+                .n_ref = 1,
+                .fd = -1,
+        };
+
+        *ret = TAKE_PTR(nd);
+
+        return 0;
+}
+
+_public_ int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *mtu) {
+        assert_return(nd, -EINVAL);
+        assert_return(mtu, -EINVAL);
+
+        if (nd->mtu == 0)
+                return -ENODATA;
+
+        *mtu = nd->mtu;
+        return 0;
+}
+
+_public_ int sd_ndisc_get_hop_limit(sd_ndisc *nd, uint8_t *ret) {
+        assert_return(nd, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (nd->hop_limit == 0)
+                return -ENODATA;
+
+        *ret = nd->hop_limit;
+        return 0;
+}
+
+static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) {
+        int r;
+
+        assert(nd);
+        assert(rt);
+
+        r = ndisc_router_parse(rt);
+        if (r == -EBADMSG) /* Bad packet */
+                return 0;
+        if (r < 0)
+                return 0;
+
+        /* Update global variables we keep */
+        if (rt->mtu > 0)
+                nd->mtu = rt->mtu;
+        if (rt->hop_limit > 0)
+                nd->hop_limit = rt->hop_limit;
+
+        log_ndisc("Received Router Advertisement: flags %s preference %s lifetime %" PRIu16 " sec",
+                  rt->flags & ND_RA_FLAG_MANAGED ? "MANAGED" : rt->flags & ND_RA_FLAG_OTHER ? "OTHER" : "none",
+                  rt->preference == SD_NDISC_PREFERENCE_HIGH ? "high" : rt->preference == SD_NDISC_PREFERENCE_LOW ? "low" : "medium",
+                  rt->lifetime);
+
+        ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt);
+        return 0;
+}
+
+static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        _cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
+        sd_ndisc *nd = userdata;
+        ssize_t buflen;
+        int r;
+        _cleanup_free_ char *addr = NULL;
+
+        assert(s);
+        assert(nd);
+        assert(nd->event);
+
+        buflen = next_datagram_size_fd(fd);
+        if (buflen < 0)
+                return log_ndisc_errno(buflen, "Failed to determine datagram size to read: %m");
+
+        rt = ndisc_router_new(buflen);
+        if (!rt)
+                return -ENOMEM;
+
+        r = icmp6_receive(fd, NDISC_ROUTER_RAW(rt), rt->raw_size, &rt->address,
+                     &rt->timestamp);
+        if (r < 0) {
+                switch (r) {
+                case -EADDRNOTAVAIL:
+                        (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &rt->address, &addr);
+                        log_ndisc("Received RA from non-link-local address %s. Ignoring", addr);
+                        break;
+
+                case -EMULTIHOP:
+                        log_ndisc("Received RA with invalid hop limit. Ignoring.");
+                        break;
+
+                case -EPFNOSUPPORT:
+                        log_ndisc("Received invalid source address from ICMPv6 socket. Ignoring.");
+                        break;
+
+                case -EAGAIN: /* ignore spurious wakeups */
+                        break;
+
+                default:
+                        log_ndisc_errno(r, "Unexpected error while reading from ICMPv6, ignoring: %m");
+                        break;
+                }
+
+                return 0;
+        }
+
+        (void) event_source_disable(nd->timeout_event_source);
+
+        return ndisc_handle_datagram(nd, rt);
+}
+
+static usec_t ndisc_timeout_compute_random(usec_t val) {
+        /* compute a time that is random within ±10% of the given value */
+        return val - val / 10 +
+                (random_u64() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
+}
+
+static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
+        char time_string[FORMAT_TIMESPAN_MAX];
+        sd_ndisc *nd = userdata;
+        usec_t time_now;
+        int r;
+
+        assert(s);
+        assert(nd);
+        assert(nd->event);
+
+        assert_se(sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now) >= 0);
+
+        if (!nd->retransmit_time)
+                nd->retransmit_time = ndisc_timeout_compute_random(NDISC_ROUTER_SOLICITATION_INTERVAL);
+        else {
+                if (nd->retransmit_time > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 2)
+                        nd->retransmit_time = ndisc_timeout_compute_random(NDISC_MAX_ROUTER_SOLICITATION_INTERVAL);
+                else
+                        nd->retransmit_time += ndisc_timeout_compute_random(nd->retransmit_time);
+        }
+
+        r = event_reset_time(nd->event, &nd->timeout_event_source,
+                             clock_boottime_or_monotonic(),
+                             time_now + nd->retransmit_time, 10 * USEC_PER_MSEC,
+                             ndisc_timeout, nd,
+                             nd->event_priority, "ndisc-timeout-no-ra", true);
+        if (r < 0)
+                goto fail;
+
+        r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr);
+        if (r < 0) {
+                log_ndisc_errno(r, "Error sending Router Solicitation: %m");
+                goto fail;
+        }
+
+        log_ndisc("Sent Router Solicitation, next solicitation in %s",
+                  format_timespan(time_string, FORMAT_TIMESPAN_MAX,
+                                  nd->retransmit_time, USEC_PER_SEC));
+
+        return 0;
+
+fail:
+        (void) sd_ndisc_stop(nd);
+        return 0;
+}
+
+static int ndisc_timeout_no_ra(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_ndisc *nd = userdata;
+
+        assert(s);
+        assert(nd);
+
+        log_ndisc("No RA received before link confirmation timeout");
+
+        (void) event_source_disable(nd->timeout_no_ra);
+        ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL);
+
+        return 0;
+}
+
+_public_ int sd_ndisc_stop(sd_ndisc *nd) {
+        if (!nd)
+                return 0;
+
+        if (nd->fd < 0)
+                return 0;
+
+        log_ndisc("Stopping IPv6 Router Solicitation client");
+
+        ndisc_reset(nd);
+        return 1;
+}
+
+_public_ int sd_ndisc_start(sd_ndisc *nd) {
+        int r;
+        usec_t time_now;
+
+        assert_return(nd, -EINVAL);
+        assert_return(nd->event, -EINVAL);
+        assert_return(nd->ifindex > 0, -EINVAL);
+
+        if (nd->fd >= 0)
+                return 0;
+
+        assert(!nd->recv_event_source);
+
+        r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                goto fail;
+
+        nd->fd = icmp6_bind_router_solicitation(nd->ifindex);
+        if (nd->fd < 0)
+                return nd->fd;
+
+        r = sd_event_add_io(nd->event, &nd->recv_event_source, nd->fd, EPOLLIN, ndisc_recv, nd);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(nd->recv_event_source, nd->event_priority);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(nd->recv_event_source, "ndisc-receive-message");
+
+        r = event_reset_time(nd->event, &nd->timeout_event_source,
+                             clock_boottime_or_monotonic(),
+                             time_now + USEC_PER_SEC / 2, 1 * USEC_PER_SEC, /* See RFC 8415 sec. 18.2.1 */
+                             ndisc_timeout, nd,
+                             nd->event_priority, "ndisc-timeout", true);
+        if (r < 0)
+                goto fail;
+
+        r = event_reset_time(nd->event, &nd->timeout_no_ra,
+                             clock_boottime_or_monotonic(),
+                             time_now + NDISC_TIMEOUT_NO_RA_USEC, 10 * USEC_PER_MSEC,
+                             ndisc_timeout_no_ra, nd,
+                             nd->event_priority, "ndisc-timeout-no-ra", true);
+        if (r < 0)
+                goto fail;
+
+        log_ndisc("Started IPv6 Router Solicitation client");
+        return 1;
+
+fail:
+        ndisc_reset(nd);
+        return r;
+}
diff --git a/src/libsystemd-network/sd-radv.c b/src/libsystemd-network/sd-radv.c
new file mode 100644
index 0000000..8beb845
--- /dev/null
+++ b/src/libsystemd-network/sd-radv.c
@@ -0,0 +1,953 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2017 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/icmp6.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "sd-radv.h"
+
+#include "alloc-util.h"
+#include "dns-domain.h"
+#include "ether-addr-util.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "icmp6-util.h"
+#include "in-addr-util.h"
+#include "io-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "radv-internal.h"
+#include "random-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+_public_ int sd_radv_new(sd_radv **ret) {
+        _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        ra = new(sd_radv, 1);
+        if (!ra)
+                return -ENOMEM;
+
+        *ra = (sd_radv) {
+                .n_ref = 1,
+                .fd = -1,
+        };
+
+        *ret = TAKE_PTR(ra);
+
+        return 0;
+}
+
+_public_ int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(ra, -EINVAL);
+        assert_return(!ra->event, -EBUSY);
+
+        if (event)
+                ra->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&ra->event);
+                if (r < 0)
+                        return 0;
+        }
+
+        ra->event_priority = priority;
+
+        return 0;
+}
+
+_public_ int sd_radv_detach_event(sd_radv *ra) {
+
+        assert_return(ra, -EINVAL);
+
+        ra->event = sd_event_unref(ra->event);
+        return 0;
+}
+
+_public_ sd_event *sd_radv_get_event(sd_radv *ra) {
+        assert_return(ra, NULL);
+
+        return ra->event;
+}
+
+_public_ int sd_radv_is_running(sd_radv *ra) {
+        assert_return(ra, false);
+
+        return ra->state != SD_RADV_STATE_IDLE;
+}
+
+static void radv_reset(sd_radv *ra) {
+        assert(ra);
+
+        (void) event_source_disable(ra->timeout_event_source);
+
+        ra->recv_event_source =
+                sd_event_source_unref(ra->recv_event_source);
+
+        ra->ra_sent = 0;
+}
+
+static sd_radv *radv_free(sd_radv *ra) {
+        if (!ra)
+                return NULL;
+
+        while (ra->prefixes) {
+                sd_radv_prefix *p = ra->prefixes;
+
+                LIST_REMOVE(prefix, ra->prefixes, p);
+                sd_radv_prefix_unref(p);
+        }
+
+        while (ra->route_prefixes) {
+                sd_radv_route_prefix *p = ra->route_prefixes;
+
+                LIST_REMOVE(prefix, ra->route_prefixes, p);
+                sd_radv_route_prefix_unref(p);
+        }
+
+        free(ra->rdnss);
+        free(ra->dnssl);
+
+        ra->timeout_event_source = sd_event_source_unref(ra->timeout_event_source);
+
+        radv_reset(ra);
+
+        sd_radv_detach_event(ra);
+
+        ra->fd = safe_close(ra->fd);
+
+        return mfree(ra);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
+
+static int radv_send(sd_radv *ra, const struct in6_addr *dst, uint32_t router_lifetime) {
+        sd_radv_route_prefix *rt;
+        sd_radv_prefix *p;
+        struct sockaddr_in6 dst_addr = {
+                .sin6_family = AF_INET6,
+                .sin6_addr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
+        };
+        struct nd_router_advert adv = {};
+        struct {
+                struct nd_opt_hdr opthdr;
+                struct ether_addr slladdr;
+        } _packed_ opt_mac = {
+                .opthdr = {
+                        .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
+                        .nd_opt_len = (sizeof(struct nd_opt_hdr) +
+                                       sizeof(struct ether_addr) - 1) /8 + 1,
+                },
+        };
+        struct nd_opt_mtu opt_mtu =  {
+                .nd_opt_mtu_type = ND_OPT_MTU,
+                .nd_opt_mtu_len = 1,
+        };
+        /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, N routes, RDNSS
+           and DNSSL */
+        struct iovec iov[5 + ra->n_prefixes + ra->n_route_prefixes];
+        struct msghdr msg = {
+                .msg_name = &dst_addr,
+                .msg_namelen = sizeof(dst_addr),
+                .msg_iov = iov,
+        };
+        usec_t time_now;
+        int r;
+
+        assert(ra);
+
+        r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                return r;
+
+        if (dst && !IN6_IS_ADDR_UNSPECIFIED(dst))
+                dst_addr.sin6_addr = *dst;
+
+        adv.nd_ra_type = ND_ROUTER_ADVERT;
+        adv.nd_ra_curhoplimit = ra->hop_limit;
+        adv.nd_ra_flags_reserved = ra->flags;
+        adv.nd_ra_router_lifetime = htobe16(router_lifetime);
+        iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
+
+        /* MAC address is optional, either because the link does not use L2
+           addresses or load sharing is desired. See RFC 4861, Section 4.2 */
+        if (!ether_addr_is_null(&ra->mac_addr)) {
+                opt_mac.slladdr = ra->mac_addr;
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
+        }
+
+        if (ra->mtu) {
+                opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu);
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
+        }
+
+        LIST_FOREACH(prefix, p, ra->prefixes) {
+                if (p->valid_until) {
+
+                        if (time_now > p->valid_until)
+                                p->opt.valid_lifetime = 0;
+                        else
+                                p->opt.valid_lifetime = htobe32((p->valid_until - time_now) / USEC_PER_SEC);
+
+                        if (time_now > p->preferred_until)
+                                p->opt.preferred_lifetime = 0;
+                        else
+                                p->opt.preferred_lifetime = htobe32((p->preferred_until - time_now) / USEC_PER_SEC);
+                }
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
+        }
+
+        LIST_FOREACH(prefix, rt, ra->route_prefixes)
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
+
+        if (ra->rdnss)
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
+
+        if (ra->dnssl)
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
+
+        if (sendmsg(ra->fd, &msg, 0) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_radv *ra = userdata;
+        _cleanup_free_ char *addr = NULL;
+        struct in6_addr src;
+        triple_timestamp timestamp;
+        int r;
+        ssize_t buflen;
+        _cleanup_free_ char *buf = NULL;
+
+        assert(s);
+        assert(ra);
+        assert(ra->event);
+
+        buflen = next_datagram_size_fd(fd);
+        if (buflen < 0)
+                return (int) buflen;
+
+        buf = new0(char, buflen);
+        if (!buf)
+                return -ENOMEM;
+
+        r = icmp6_receive(fd, buf, buflen, &src, &timestamp);
+        if (r < 0) {
+                switch (r) {
+                case -EADDRNOTAVAIL:
+                        (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr);
+                        log_radv("Received RS from non-link-local address %s. Ignoring", addr);
+                        break;
+
+                case -EMULTIHOP:
+                        log_radv("Received RS with invalid hop limit. Ignoring.");
+                        break;
+
+                case -EPFNOSUPPORT:
+                        log_radv("Received invalid source address from ICMPv6 socket. Ignoring.");
+                        break;
+
+                case -EAGAIN: /* ignore spurious wakeups */
+                        break;
+
+                default:
+                        log_radv_errno(r, "Unexpected error receiving from ICMPv6 socket: %m");
+                        break;
+                }
+
+                return 0;
+        }
+
+        if ((size_t) buflen < sizeof(struct nd_router_solicit)) {
+                log_radv("Too short packet received");
+                return 0;
+        }
+
+        (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr);
+
+        r = radv_send(ra, &src, ra->lifetime);
+        if (r < 0)
+                log_radv_errno(r, "Unable to send solicited Router Advertisement to %s: %m", strnull(addr));
+        else
+                log_radv("Sent solicited Router Advertisement to %s", strnull(addr));
+
+        return 0;
+}
+
+static usec_t radv_compute_timeout(usec_t min, usec_t max) {
+        assert_return(min <= max, SD_RADV_DEFAULT_MIN_TIMEOUT_USEC);
+
+        /* RFC 4861: min must be no less than 3s, max must be no less than 4s */
+        min = MAX(min, 3*USEC_PER_SEC);
+        max = MAX(max, 4*USEC_PER_SEC);
+
+        return min + (random_u32() % (max - min));
+}
+
+static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
+        int r;
+        sd_radv *ra = userdata;
+        usec_t min_timeout = SD_RADV_DEFAULT_MIN_TIMEOUT_USEC;
+        usec_t max_timeout = SD_RADV_DEFAULT_MAX_TIMEOUT_USEC;
+        usec_t time_now, timeout;
+        char time_string[FORMAT_TIMESPAN_MAX];
+
+        assert(s);
+        assert(ra);
+        assert(ra->event);
+
+        r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                goto fail;
+
+        r = radv_send(ra, NULL, ra->lifetime);
+        if (r < 0)
+                log_radv_errno(r, "Unable to send Router Advertisement: %m");
+
+        /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
+        if (ra->ra_sent < SD_RADV_MAX_INITIAL_RTR_ADVERTISEMENTS) {
+                max_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
+                min_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC / 3;
+        }
+
+        /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
+           so lower the interval here */
+        if (ra->lifetime > 0 && (ra->lifetime * USEC_PER_SEC) < max_timeout) {
+                max_timeout = ra->lifetime * USEC_PER_SEC;
+                min_timeout = max_timeout / 3;
+        }
+
+        timeout = radv_compute_timeout(min_timeout, max_timeout);
+
+        log_radv("Next Router Advertisement in %s",
+                 format_timespan(time_string, FORMAT_TIMESPAN_MAX,
+                                 timeout, USEC_PER_SEC));
+
+        r = event_reset_time(ra->event, &ra->timeout_event_source,
+                             clock_boottime_or_monotonic(),
+                             time_now + timeout, MSEC_PER_SEC,
+                             radv_timeout, ra,
+                             ra->event_priority, "radv-timeout", true);
+        if (r < 0)
+                goto fail;
+
+        ra->ra_sent++;
+
+        return 0;
+
+fail:
+        sd_radv_stop(ra);
+
+        return 0;
+}
+
+_public_ int sd_radv_stop(sd_radv *ra) {
+        int r;
+
+        if (!ra)
+                return 0;
+
+        if (ra->state == SD_RADV_STATE_IDLE)
+                return 0;
+
+        log_radv("Stopping IPv6 Router Advertisement daemon");
+
+        /* RFC 4861, Section 6.2.5, send at least one Router Advertisement
+           with zero lifetime  */
+        r = radv_send(ra, NULL, 0);
+        if (r < 0)
+                log_radv_errno(r, "Unable to send last Router Advertisement with router lifetime set to zero: %m");
+
+        radv_reset(ra);
+        ra->fd = safe_close(ra->fd);
+        ra->state = SD_RADV_STATE_IDLE;
+
+        return 0;
+}
+
+_public_ int sd_radv_start(sd_radv *ra) {
+        int r;
+
+        assert_return(ra, -EINVAL);
+        assert_return(ra->event, -EINVAL);
+        assert_return(ra->ifindex > 0, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return 0;
+
+        r = event_reset_time(ra->event, &ra->timeout_event_source,
+                             clock_boottime_or_monotonic(),
+                             0, 0,
+                             radv_timeout, ra,
+                             ra->event_priority, "radv-timeout", true);
+        if (r < 0)
+                goto fail;
+
+        r = icmp6_bind_router_advertisement(ra->ifindex);
+        if (r < 0)
+                goto fail;
+
+        ra->fd = r;
+
+        r = sd_event_add_io(ra->event, &ra->recv_event_source, ra->fd, EPOLLIN, radv_recv, ra);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(ra->recv_event_source, ra->event_priority);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(ra->recv_event_source, "radv-receive-message");
+
+        ra->state = SD_RADV_STATE_ADVERTISING;
+
+        log_radv("Started IPv6 Router Advertisement daemon");
+
+        return 0;
+
+ fail:
+        radv_reset(ra);
+
+        return r;
+}
+
+_public_ int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
+        assert_return(ra, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return -EBUSY;
+
+        ra->ifindex = ifindex;
+
+        return 0;
+}
+
+_public_ int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return -EBUSY;
+
+        if (mac_addr)
+                ra->mac_addr = *mac_addr;
+        else
+                zero(ra->mac_addr);
+
+        return 0;
+}
+
+_public_ int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
+        assert_return(ra, -EINVAL);
+        assert_return(mtu >= 1280, -EINVAL);
+
+        ra->mtu = mtu;
+
+        return 0;
+}
+
+_public_ int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return -EBUSY;
+
+        ra->hop_limit = hop_limit;
+
+        return 0;
+}
+
+_public_ int sd_radv_set_router_lifetime(sd_radv *ra, uint16_t router_lifetime) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return -EBUSY;
+
+        /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
+         * to (00) by the sender..." */
+        if (router_lifetime == 0 &&
+            (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
+                return -ETIME;
+
+        ra->lifetime = router_lifetime;
+
+        return 0;
+}
+
+_public_ int sd_radv_set_managed_information(sd_radv *ra, int managed) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return -EBUSY;
+
+        SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
+
+        return 0;
+}
+
+_public_ int sd_radv_set_other_information(sd_radv *ra, int other) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != SD_RADV_STATE_IDLE)
+                return -EBUSY;
+
+        SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
+
+        return 0;
+}
+
+_public_ int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
+        assert_return(ra, -EINVAL);
+        assert_return(IN_SET(preference,
+                             SD_NDISC_PREFERENCE_LOW,
+                             SD_NDISC_PREFERENCE_MEDIUM,
+                             SD_NDISC_PREFERENCE_HIGH), -EINVAL);
+
+        /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
+         * to (00) by the sender..." */
+        if (ra->lifetime == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
+                return -EINVAL;
+
+        ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
+
+        return 0;
+}
+
+_public_ int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p, int dynamic) {
+        sd_radv_prefix *cur;
+        int r;
+        _cleanup_free_ char *addr_p = NULL;
+        char time_string_preferred[FORMAT_TIMESPAN_MAX];
+        char time_string_valid[FORMAT_TIMESPAN_MAX];
+        usec_t time_now, valid, preferred, valid_until, preferred_until;
+
+        assert_return(ra, -EINVAL);
+
+        if (!p)
+                return -EINVAL;
+
+        /* Refuse prefixes that don't have a prefix set */
+        if (IN6_IS_ADDR_UNSPECIFIED(&p->opt.in6_addr))
+                return -ENOEXEC;
+
+        LIST_FOREACH(prefix, cur, ra->prefixes) {
+
+                r = in_addr_prefix_intersect(AF_INET6,
+                                             (union in_addr_union*) &cur->opt.in6_addr,
+                                             cur->opt.prefixlen,
+                                             (union in_addr_union*) &p->opt.in6_addr,
+                                             p->opt.prefixlen);
+                if (r > 0) {
+                        _cleanup_free_ char *addr_cur = NULL;
+
+                        (void) in_addr_to_string(AF_INET6,
+                                                 (union in_addr_union*) &p->opt.in6_addr,
+                                                 &addr_p);
+
+                        if (dynamic && cur->opt.prefixlen == p->opt.prefixlen)
+                                goto update;
+
+                        (void) in_addr_to_string(AF_INET6,
+                                                 (union in_addr_union*) &cur->opt.in6_addr,
+                                                 &addr_cur);
+                        log_radv("IPv6 prefix %s/%u already configured, ignoring %s/%u",
+                                 addr_cur, cur->opt.prefixlen,
+                                 addr_p, p->opt.prefixlen);
+
+                        return -EEXIST;
+                }
+        }
+
+        p = sd_radv_prefix_ref(p);
+
+        LIST_APPEND(prefix, ra->prefixes, p);
+
+        ra->n_prefixes++;
+
+        (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &p->opt.in6_addr, &addr_p);
+
+        if (!dynamic) {
+                log_radv("Added prefix %s/%d", addr_p, p->opt.prefixlen);
+                return 0;
+        }
+
+        cur = p;
+
+        /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
+        if (ra->ra_sent > 0) {
+                r = radv_send(ra, NULL, ra->lifetime);
+                if (r < 0)
+                        log_radv_errno(r, "Unable to send Router Advertisement for added prefix: %m");
+                else
+                        log_radv("Sent Router Advertisement for added prefix");
+        }
+
+ update:
+        r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                return r;
+
+        valid = be32toh(p->opt.valid_lifetime) * USEC_PER_SEC;
+        valid_until = usec_add(valid, time_now);
+        if (valid_until == USEC_INFINITY)
+                return -EOVERFLOW;
+
+        preferred = be32toh(p->opt.preferred_lifetime) * USEC_PER_SEC;
+        preferred_until = usec_add(preferred, time_now);
+        if (preferred_until == USEC_INFINITY)
+                return -EOVERFLOW;
+
+        cur->valid_until = valid_until;
+        cur->preferred_until = preferred_until;
+
+        log_radv("Updated prefix %s/%u preferred %s valid %s",
+                 addr_p, p->opt.prefixlen,
+                 format_timespan(time_string_preferred, FORMAT_TIMESPAN_MAX,
+                                 preferred, USEC_PER_SEC),
+                 format_timespan(time_string_valid, FORMAT_TIMESPAN_MAX,
+                                 valid, USEC_PER_SEC));
+
+        return 0;
+}
+
+_public_ sd_radv_prefix *sd_radv_remove_prefix(sd_radv *ra,
+                                               const struct in6_addr *prefix,
+                                               unsigned char prefixlen) {
+        sd_radv_prefix *cur, *next;
+
+        assert_return(ra, NULL);
+        assert_return(prefix, NULL);
+
+        LIST_FOREACH_SAFE(prefix, cur, next, ra->prefixes) {
+                if (prefixlen != cur->opt.prefixlen)
+                        continue;
+
+                if (!in_addr_equal(AF_INET6,
+                                   (union in_addr_union *)prefix,
+                                   (union in_addr_union *)&cur->opt.in6_addr))
+                        continue;
+
+                LIST_REMOVE(prefix, ra->prefixes, cur);
+                ra->n_prefixes--;
+                sd_radv_prefix_unref(cur);
+
+                break;
+        }
+
+        return cur;
+}
+
+_public_ int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p, int dynamic) {
+        char time_string_valid[FORMAT_TIMESPAN_MAX];
+        usec_t time_now, valid, valid_until;
+        _cleanup_free_ char *pretty = NULL;
+        sd_radv_route_prefix *cur;
+        int r;
+
+        assert_return(ra, -EINVAL);
+
+        if (!p)
+                return -EINVAL;
+
+        (void) in_addr_to_string(AF_INET6,
+                                 (union in_addr_union*) &p->opt.in6_addr,
+                                 &pretty);
+
+        LIST_FOREACH(prefix, cur, ra->route_prefixes) {
+                _cleanup_free_ char *addr = NULL;
+
+                r = in_addr_prefix_intersect(AF_INET6,
+                                             (union in_addr_union*) &cur->opt.in6_addr,
+                                             cur->opt.prefixlen,
+                                             (union in_addr_union*) &p->opt.in6_addr,
+                                             p->opt.prefixlen);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (dynamic && cur->opt.prefixlen == p->opt.prefixlen)
+                        goto update;
+
+                (void) in_addr_to_string(AF_INET6,
+                                         (union in_addr_union*) &cur->opt.in6_addr,
+                                         &addr);
+                log_radv("IPv6 route prefix %s/%u already configured, ignoring %s/%u",
+                         strempty(addr), cur->opt.prefixlen,
+                         strempty(pretty), p->opt.prefixlen);
+
+                return -EEXIST;
+        }
+
+        p = sd_radv_route_prefix_ref(p);
+
+        LIST_APPEND(prefix, ra->route_prefixes, p);
+        ra->n_route_prefixes++;
+
+        if (!dynamic) {
+                log_radv("Added prefix %s/%u", strempty(pretty), p->opt.prefixlen);
+                return 0;
+        }
+
+        /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
+        if (ra->ra_sent > 0) {
+                r = radv_send(ra, NULL, ra->lifetime);
+                if (r < 0)
+                        log_radv_errno(r, "Unable to send Router Advertisement for added route prefix: %m");
+                else
+                        log_radv("Sent Router Advertisement for added route prefix");
+        }
+
+ update:
+        r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
+        if (r < 0)
+                return r;
+
+        valid = be32toh(p->opt.lifetime) * USEC_PER_SEC;
+        valid_until = usec_add(valid, time_now);
+        if (valid_until == USEC_INFINITY)
+                return -EOVERFLOW;
+
+        log_radv("Updated route prefix %s/%u valid %s",
+                 strempty(pretty), p->opt.prefixlen,
+                 format_timespan(time_string_valid, FORMAT_TIMESPAN_MAX, valid, USEC_PER_SEC));
+
+        return 0;
+}
+
+_public_ int sd_radv_set_rdnss(sd_radv *ra, uint32_t lifetime,
+                               const struct in6_addr *dns, size_t n_dns) {
+        _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
+        size_t len;
+
+        assert_return(ra, -EINVAL);
+        assert_return(n_dns < 128, -EINVAL);
+
+        if (!dns || n_dns == 0) {
+                ra->rdnss = mfree(ra->rdnss);
+                ra->n_rdnss = 0;
+
+                return 0;
+        }
+
+        len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
+
+        opt_rdnss = malloc0(len);
+        if (!opt_rdnss)
+                return -ENOMEM;
+
+        opt_rdnss->type = SD_RADV_OPT_RDNSS;
+        opt_rdnss->length = len / 8;
+        opt_rdnss->lifetime = htobe32(lifetime);
+
+        memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
+
+        free_and_replace(ra->rdnss, opt_rdnss);
+
+        ra->n_rdnss = n_dns;
+
+        return 0;
+}
+
+_public_ int sd_radv_set_dnssl(sd_radv *ra, uint32_t lifetime,
+                               char **search_list) {
+        _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
+        size_t len = 0;
+        char **s;
+        uint8_t *p;
+
+        assert_return(ra, -EINVAL);
+
+        if (strv_isempty(search_list)) {
+                ra->dnssl = mfree(ra->dnssl);
+                return 0;
+        }
+
+        STRV_FOREACH(s, search_list)
+                len += strlen(*s) + 2;
+
+        len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
+
+        opt_dnssl = malloc0(len);
+        if (!opt_dnssl)
+                return -ENOMEM;
+
+        opt_dnssl->type = SD_RADV_OPT_DNSSL;
+        opt_dnssl->length = len / 8;
+        opt_dnssl->lifetime = htobe32(lifetime);
+
+        p = (uint8_t *)(opt_dnssl + 1);
+        len -= sizeof(struct sd_radv_opt_dns);
+
+        STRV_FOREACH(s, search_list) {
+                int r;
+
+                r = dns_name_to_wire_format(*s, p, len, false);
+                if (r < 0)
+                        return r;
+
+                if (len < (size_t)r)
+                        return -ENOBUFS;
+
+                p += r;
+                len -= r;
+        }
+
+        free_and_replace(ra->dnssl, opt_dnssl);
+
+        return 0;
+}
+
+_public_ int sd_radv_prefix_new(sd_radv_prefix **ret) {
+        sd_radv_prefix *p;
+
+        assert_return(ret, -EINVAL);
+
+        p = new(sd_radv_prefix, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (sd_radv_prefix) {
+                .n_ref = 1,
+
+                .opt.type = ND_OPT_PREFIX_INFORMATION,
+                .opt.length = (sizeof(p->opt) - 1)/8 + 1,
+                .opt.prefixlen = 64,
+
+                /* RFC 4861, Section 6.2.1 */
+                .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
+
+                .opt.preferred_lifetime = htobe32(604800),
+                .opt.valid_lifetime = htobe32(2592000),
+        };
+
+        *ret = p;
+        return 0;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
+
+_public_ int sd_radv_prefix_set_prefix(sd_radv_prefix *p, const struct in6_addr *in6_addr,
+                                       unsigned char prefixlen) {
+        assert_return(p, -EINVAL);
+        assert_return(in6_addr, -EINVAL);
+
+        if (prefixlen < 3 || prefixlen > 128)
+                return -EINVAL;
+
+        if (prefixlen > 64)
+                /* unusual but allowed, log it */
+                log_radv("Unusual prefix length %d greater than 64", prefixlen);
+
+        p->opt.in6_addr = *in6_addr;
+        p->opt.prefixlen = prefixlen;
+
+        return 0;
+}
+
+_public_ int sd_radv_prefix_get_prefix(sd_radv_prefix *p, struct in6_addr *ret_in6_addr,
+                                       unsigned char *ret_prefixlen) {
+        assert_return(p, -EINVAL);
+        assert_return(ret_in6_addr, -EINVAL);
+        assert_return(ret_prefixlen, -EINVAL);
+
+        *ret_in6_addr = p->opt.in6_addr;
+        *ret_prefixlen = p->opt.prefixlen;
+
+        return 0;
+}
+
+_public_ int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
+        assert_return(p, -EINVAL);
+
+        SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
+
+        return 0;
+}
+
+_public_ int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p,
+                                                          int address_autoconfiguration) {
+        assert_return(p, -EINVAL);
+
+        SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
+
+        return 0;
+}
+
+_public_ int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p,
+                                               uint32_t valid_lifetime) {
+        assert_return(p, -EINVAL);
+
+        p->opt.valid_lifetime = htobe32(valid_lifetime);
+
+        return 0;
+}
+
+_public_ int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p,
+                                                   uint32_t preferred_lifetime) {
+        assert_return(p, -EINVAL);
+
+        p->opt.preferred_lifetime = htobe32(preferred_lifetime);
+
+        return 0;
+}
+
+_public_ int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
+        sd_radv_route_prefix *p;
+
+        assert_return(ret, -EINVAL);
+
+        p = new(sd_radv_route_prefix, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (sd_radv_route_prefix) {
+                .n_ref = 1,
+
+                .opt.type = SD_RADV_OPT_ROUTE_INFORMATION,
+                .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
+                .opt.prefixlen = 64,
+
+                .opt.lifetime = htobe32(604800),
+        };
+
+        *ret = p;
+        return 0;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
+
+_public_ int sd_radv_prefix_set_route_prefix(sd_radv_route_prefix *p, const struct in6_addr *in6_addr,
+                                             unsigned char prefixlen) {
+        assert_return(p, -EINVAL);
+        assert_return(in6_addr, -EINVAL);
+
+        if (prefixlen > 128)
+                return -EINVAL;
+
+        if (prefixlen > 64)
+                /* unusual but allowed, log it */
+                log_radv("Unusual prefix length %u greater than 64", prefixlen);
+
+        p->opt.in6_addr = *in6_addr;
+        p->opt.prefixlen = prefixlen;
+
+        return 0;
+}
+
+_public_ int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint32_t valid_lifetime) {
+        assert_return(p, -EINVAL);
+
+        p->opt.lifetime = htobe32(valid_lifetime);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-acd.c b/src/libsystemd-network/test-acd.c
new file mode 100644
index 0000000..f4aab85
--- /dev/null
+++ b/src/libsystemd-network/test-acd.c
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <linux/veth.h>
+#include <net/if.h>
+
+#include "sd-event.h"
+#include "sd-ipv4acd.h"
+#include "sd-netlink.h"
+
+#include "in-addr-util.h"
+#include "netlink-util.h"
+#include "tests.h"
+#include "util.h"
+
+static void acd_handler(sd_ipv4acd *acd, int event, void *userdata) {
+        assert_se(acd);
+
+        switch (event) {
+        case SD_IPV4ACD_EVENT_BIND:
+                log_info("bound");
+                break;
+        case SD_IPV4ACD_EVENT_CONFLICT:
+                log_info("conflict");
+                break;
+        case SD_IPV4ACD_EVENT_STOP:
+                log_error("the client was stopped");
+                break;
+        default:
+                assert_not_reached("invalid ACD event");
+        }
+}
+
+static int client_run(int ifindex, const struct in_addr *pa, const struct ether_addr *ha, sd_event *e) {
+        sd_ipv4acd *acd;
+
+        assert_se(sd_ipv4acd_new(&acd) >= 0);
+        assert_se(sd_ipv4acd_attach_event(acd, e, 0) >= 0);
+
+        assert_se(sd_ipv4acd_set_ifindex(acd, ifindex) >= 0);
+        assert_se(sd_ipv4acd_set_mac(acd, ha) >= 0);
+        assert_se(sd_ipv4acd_set_address(acd, pa) >= 0);
+        assert_se(sd_ipv4acd_set_callback(acd, acd_handler, NULL) >= 0);
+
+        log_info("starting IPv4ACD client");
+
+        assert_se(sd_ipv4acd_start(acd, true) >= 0);
+
+        assert_se(sd_event_loop(e) >= 0);
+
+        assert_se(!sd_ipv4acd_unref(acd));
+
+        return EXIT_SUCCESS;
+}
+
+static int test_acd(const char *ifname, const char *address) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *reply = NULL;
+        union in_addr_union pa;
+        struct ether_addr ha;
+        int ifindex;
+
+        assert_se(in_addr_from_string(AF_INET, address, &pa) >= 0);
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+        assert_se(sd_netlink_attach_event(rtnl, e, 0) >= 0);
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, 0) >= 0);
+        assert_se(sd_netlink_message_append_string(m, IFLA_IFNAME, ifname) >= 0);
+        assert_se(sd_netlink_call(rtnl, m, 0, &reply) >= 0);
+
+        assert_se(sd_rtnl_message_link_get_ifindex(reply, &ifindex) >= 0);
+        assert_se(sd_netlink_message_read_ether_addr(reply, IFLA_ADDRESS, &ha) >= 0);
+
+        client_run(ifindex, &pa.in, &ha, e);
+
+        return EXIT_SUCCESS;
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_DEBUG);
+
+        if (argc == 3)
+                return test_acd(argv[1], argv[2]);
+        else {
+                log_error("This program takes two arguments.\n"
+                          "\t %s <ifname> <IPv4 address>", program_invocation_short_name);
+                return EXIT_FAILURE;
+        }
+}
diff --git a/src/libsystemd-network/test-dhcp-client.c b/src/libsystemd-network/test-dhcp-client.c
new file mode 100644
index 0000000..d39d1f5
--- /dev/null
+++ b/src/libsystemd-network/test-dhcp-client.c
@@ -0,0 +1,570 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "sd-dhcp-client.h"
+#include "sd-event.h"
+
+#include "alloc-util.h"
+#include "dhcp-identifier.h"
+#include "dhcp-internal.h"
+#include "dhcp-protocol.h"
+#include "fd-util.h"
+#include "random-util.h"
+#include "tests.h"
+#include "util.h"
+
+static uint8_t mac_addr[] = {'A', 'B', 'C', '1', '2', '3'};
+static uint8_t bcast_addr[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+
+typedef int (*test_callback_recv_t)(size_t size, DHCPMessage *dhcp);
+
+static bool verbose = true;
+static int test_fd[2];
+static test_callback_recv_t callback_recv;
+static be32_t xid;
+static sd_event_source *test_hangcheck;
+
+static int test_dhcp_hangcheck(sd_event_source *s, uint64_t usec, void *userdata) {
+        assert_not_reached("Test case should have completed in 2 seconds");
+
+        return 0;
+}
+
+static void test_request_basic(sd_event *e) {
+        int r;
+
+        sd_dhcp_client *client;
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        /* Initialize client without Anonymize settings. */
+        r = sd_dhcp_client_new(&client, false);
+
+        assert_se(r >= 0);
+        assert_se(client);
+
+        r = sd_dhcp_client_attach_event(client, e, 0);
+        assert_se(r >= 0);
+
+        assert_se(sd_dhcp_client_set_request_option(NULL, 0) == -EINVAL);
+        assert_se(sd_dhcp_client_set_request_address(NULL, NULL) == -EINVAL);
+        assert_se(sd_dhcp_client_set_ifindex(NULL, 0) == -EINVAL);
+
+        assert_se(sd_dhcp_client_set_ifindex(client, 15) == 0);
+        assert_se(sd_dhcp_client_set_ifindex(client, -42) == -EINVAL);
+        assert_se(sd_dhcp_client_set_ifindex(client, -1) == -EINVAL);
+        assert_se(sd_dhcp_client_set_ifindex(client, 0) == -EINVAL);
+        assert_se(sd_dhcp_client_set_ifindex(client, 1) == 0);
+
+        assert_se(sd_dhcp_client_set_hostname(client, "host") == 1);
+        assert_se(sd_dhcp_client_set_hostname(client, "host.domain") == 1);
+        assert_se(sd_dhcp_client_set_hostname(client, NULL) == 1);
+        assert_se(sd_dhcp_client_set_hostname(client, "~host") == -EINVAL);
+        assert_se(sd_dhcp_client_set_hostname(client, "~host.domain") == -EINVAL);
+
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_SUBNET_MASK) == 0);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_ROUTER) == 0);
+        /* This PRL option is not set when using Anonymize, but in this test
+         * Anonymize settings are not being used. */
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_HOST_NAME) == 0);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_DOMAIN_NAME) == 0);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_DOMAIN_NAME_SERVER) == 0);
+
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_PAD) == -EINVAL);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_END) == -EINVAL);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_MESSAGE_TYPE) == -EINVAL);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_OVERLOAD) == -EINVAL);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_PARAMETER_REQUEST_LIST) == -EINVAL);
+
+        /* RFC7844: option 33 (SD_DHCP_OPTION_STATIC_ROUTE) is set in the
+         * default PRL when using Anonymize, so it is changed to other option
+         * that is not set by default, to check that it was set successfully.
+         * Options not set by default (using or not anonymize) are option 17
+         * (SD_DHCP_OPTION_ROOT_PATH) and 42 (SD_DHCP_OPTION_NTP_SERVER) */
+        assert_se(sd_dhcp_client_set_request_option(client, 17) == 1);
+        assert_se(sd_dhcp_client_set_request_option(client, 17) == 0);
+        assert_se(sd_dhcp_client_set_request_option(client, 42) == 1);
+        assert_se(sd_dhcp_client_set_request_option(client, 17) == 0);
+
+        sd_dhcp_client_unref(client);
+}
+
+static void test_request_anonymize(sd_event *e) {
+        int r;
+
+        sd_dhcp_client *client;
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        /* Initialize client with Anonymize settings. */
+        r = sd_dhcp_client_new(&client, true);
+
+        assert_se(r >= 0);
+        assert_se(client);
+
+        r = sd_dhcp_client_attach_event(client, e, 0);
+        assert_se(r >= 0);
+
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_NETBIOS_NAMESERVER) == 0);
+        /* This PRL option is not set when using Anonymize */
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_HOST_NAME) == 1);
+        assert_se(sd_dhcp_client_set_request_option(client, SD_DHCP_OPTION_PARAMETER_REQUEST_LIST) == -EINVAL);
+
+        /* RFC7844: option 101 (SD_DHCP_OPTION_NEW_TZDB_TIMEZONE) is not set in the
+         * default PRL when using Anonymize, */
+        assert_se(sd_dhcp_client_set_request_option(client, 101) == 1);
+        assert_se(sd_dhcp_client_set_request_option(client, 101) == 0);
+
+        sd_dhcp_client_unref(client);
+}
+
+static void test_checksum(void) {
+        uint8_t buf[20] = {
+                0x45, 0x00, 0x02, 0x40, 0x00, 0x00, 0x00, 0x00,
+                0x40, 0x11, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0xff, 0xff, 0xff, 0xff
+        };
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        assert_se(dhcp_packet_checksum((uint8_t*)&buf, 20) == be16toh(0x78ae));
+}
+
+static void test_dhcp_identifier_set_iaid(void) {
+        uint32_t iaid_legacy;
+        be32_t iaid;
+        int ifindex;
+
+        for (;;) {
+                char ifname[IFNAMSIZ];
+
+                /* try to find an ifindex which does not exist. I causes dhcp_identifier_set_iaid()
+                 * to hash the MAC address. */
+                pseudo_random_bytes(&ifindex, sizeof(ifindex));
+                if (ifindex > 0 && !if_indextoname(ifindex, ifname))
+                        break;
+        }
+
+        assert_se(dhcp_identifier_set_iaid(ifindex, mac_addr, sizeof(mac_addr), true, &iaid_legacy) >= 0);
+        assert_se(dhcp_identifier_set_iaid(ifindex, mac_addr, sizeof(mac_addr), false, &iaid) >= 0);
+
+        /* we expect, that the MAC address was hashed. The legacy value is in native
+         * endianness. */
+        assert_se(iaid_legacy == 0x8dde4ba8u);
+        assert_se(iaid  == htole32(0x8dde4ba8u));
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+        assert_se(iaid == iaid_legacy);
+#else
+        assert_se(iaid == __bswap_32(iaid_legacy));
+#endif
+}
+
+static int check_options(uint8_t code, uint8_t len, const void *option, void *userdata) {
+        switch(code) {
+        case SD_DHCP_OPTION_CLIENT_IDENTIFIER:
+        {
+                uint32_t iaid;
+                struct duid duid;
+                size_t duid_len;
+
+                assert_se(dhcp_identifier_set_duid_en(&duid, &duid_len) >= 0);
+                assert_se(dhcp_identifier_set_iaid(42, mac_addr, ETH_ALEN, true, &iaid) >= 0);
+
+                assert_se(len == sizeof(uint8_t) + sizeof(uint32_t) + duid_len);
+                assert_se(len == 19);
+                assert_se(((uint8_t*) option)[0] == 0xff);
+
+                assert_se(memcmp((uint8_t*) option + 1, &iaid, sizeof(iaid)) == 0);
+                assert_se(memcmp((uint8_t*) option + 5, &duid, duid_len) == 0);
+                break;
+        }
+
+        default:
+                break;
+        }
+
+        return 0;
+}
+
+int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link, const void *packet, size_t len) {
+        size_t size;
+        _cleanup_free_ DHCPPacket *discover;
+        uint16_t ip_check, udp_check;
+
+        assert_se(s >= 0);
+        assert_se(packet);
+
+        size = sizeof(DHCPPacket);
+        assert_se(len > size);
+
+        discover = memdup(packet, len);
+
+        assert_se(discover->ip.ttl == IPDEFTTL);
+        assert_se(discover->ip.protocol == IPPROTO_UDP);
+        assert_se(discover->ip.saddr == INADDR_ANY);
+        assert_se(discover->ip.daddr == INADDR_BROADCAST);
+        assert_se(discover->udp.source == be16toh(DHCP_PORT_CLIENT));
+        assert_se(discover->udp.dest == be16toh(DHCP_PORT_SERVER));
+
+        ip_check = discover->ip.check;
+
+        discover->ip.ttl = 0;
+        discover->ip.check = discover->udp.len;
+
+        udp_check = ~dhcp_packet_checksum((uint8_t*)&discover->ip.ttl, len - 8);
+        assert_se(udp_check == 0xffff);
+
+        discover->ip.ttl = IPDEFTTL;
+        discover->ip.check = ip_check;
+
+        ip_check = ~dhcp_packet_checksum((uint8_t*)&discover->ip, sizeof(discover->ip));
+        assert_se(ip_check == 0xffff);
+
+        assert_se(discover->dhcp.xid);
+        assert_se(memcmp(discover->dhcp.chaddr, &mac_addr, ETH_ALEN) == 0);
+
+        size = len - sizeof(struct iphdr) - sizeof(struct udphdr);
+
+        assert_se(callback_recv);
+        callback_recv(size, &discover->dhcp);
+
+        return 575;
+}
+
+int dhcp_network_bind_raw_socket(
+                int ifindex,
+                union sockaddr_union *link,
+                uint32_t id,
+                const uint8_t *addr, size_t addr_len,
+                const uint8_t *bcaddr, size_t bcaddr_len,
+                uint16_t arp_type, uint16_t port) {
+
+        if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_fd) < 0)
+                return -errno;
+
+        return test_fd[0];
+}
+
+int dhcp_network_bind_udp_socket(int ifindex, be32_t address, uint16_t port, int ip_service_type) {
+        int fd;
+
+        fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (fd < 0)
+                return -errno;
+
+        return fd;
+}
+
+int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port, const void *packet, size_t len) {
+        return 0;
+}
+
+static int test_discover_message_verify(size_t size, struct DHCPMessage *dhcp) {
+        int res;
+
+        res = dhcp_option_parse(dhcp, size, check_options, NULL, NULL);
+        assert_se(res == DHCP_DISCOVER);
+
+        if (verbose)
+                printf("  recv DHCP Discover 0x%08x\n", be32toh(dhcp->xid));
+
+        return 0;
+}
+
+static void test_discover_message(sd_event *e) {
+        sd_dhcp_client *client;
+        int res, r;
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        r = sd_dhcp_client_new(&client, false);
+        assert_se(r >= 0);
+        assert_se(client);
+
+        r = sd_dhcp_client_attach_event(client, e, 0);
+        assert_se(r >= 0);
+
+        assert_se(sd_dhcp_client_set_ifindex(client, 42) >= 0);
+        assert_se(sd_dhcp_client_set_mac(client, mac_addr, bcast_addr, ETH_ALEN, ARPHRD_ETHER) >= 0);
+
+        assert_se(sd_dhcp_client_set_request_option(client, 248) >= 0);
+
+        callback_recv = test_discover_message_verify;
+
+        res = sd_dhcp_client_start(client);
+
+        assert_se(IN_SET(res, 0, -EINPROGRESS));
+
+        sd_event_run(e, (uint64_t) -1);
+
+        sd_dhcp_client_stop(client);
+        sd_dhcp_client_unref(client);
+
+        test_fd[1] = safe_close(test_fd[1]);
+
+        callback_recv = NULL;
+}
+
+static uint8_t test_addr_acq_offer[] = {
+        0x45, 0x10, 0x01, 0x48, 0x00, 0x00, 0x00, 0x00,
+        0x80, 0x11, 0xb3, 0x84, 0xc0, 0xa8, 0x02, 0x01,
+        0xc0, 0xa8, 0x02, 0xbf, 0x00, 0x43, 0x00, 0x44,
+        0x01, 0x34, 0x00, 0x00, 0x02, 0x01, 0x06, 0x00,
+        0x6f, 0x95, 0x2f, 0x30, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0xc0, 0xa8, 0x02, 0xbf,
+        0xc0, 0xa8, 0x02, 0x01, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x63, 0x82, 0x53, 0x63, 0x35, 0x01, 0x02, 0x36,
+        0x04, 0xc0, 0xa8, 0x02, 0x01, 0x33, 0x04, 0x00,
+        0x00, 0x02, 0x58, 0x01, 0x04, 0xff, 0xff, 0xff,
+        0x00, 0x2a, 0x04, 0xc0, 0xa8, 0x02, 0x01, 0x0f,
+        0x09, 0x6c, 0x61, 0x62, 0x2e, 0x69, 0x6e, 0x74,
+        0x72, 0x61, 0x03, 0x04, 0xc0, 0xa8, 0x02, 0x01,
+        0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+};
+
+static uint8_t test_addr_acq_ack[] = {
+        0x45, 0x10, 0x01, 0x48, 0x00, 0x00, 0x00, 0x00,
+        0x80, 0x11, 0xb3, 0x84, 0xc0, 0xa8, 0x02, 0x01,
+        0xc0, 0xa8, 0x02, 0xbf, 0x00, 0x43, 0x00, 0x44,
+        0x01, 0x34, 0x00, 0x00, 0x02, 0x01, 0x06, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0xc0, 0xa8, 0x02, 0xbf,
+        0xc0, 0xa8, 0x02, 0x01, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x63, 0x82, 0x53, 0x63, 0x35, 0x01, 0x05, 0x36,
+        0x04, 0xc0, 0xa8, 0x02, 0x01, 0x33, 0x04, 0x00,
+        0x00, 0x02, 0x58, 0x01, 0x04, 0xff, 0xff, 0xff,
+        0x00, 0x2a, 0x04, 0xc0, 0xa8, 0x02, 0x01, 0x0f,
+        0x09, 0x6c, 0x61, 0x62, 0x2e, 0x69, 0x6e, 0x74,
+        0x72, 0x61, 0x03, 0x04, 0xc0, 0xa8, 0x02, 0x01,
+        0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+};
+
+static int test_addr_acq_acquired(sd_dhcp_client *client, int event,
+                                   void *userdata) {
+        sd_event *e = userdata;
+        sd_dhcp_lease *lease;
+        struct in_addr addr;
+        const struct in_addr *addrs;
+
+        assert_se(client);
+        assert_se(IN_SET(event, SD_DHCP_CLIENT_EVENT_IP_ACQUIRE, SD_DHCP_CLIENT_EVENT_SELECTING));
+
+        assert_se(sd_dhcp_client_get_lease(client, &lease) >= 0);
+        assert_se(lease);
+
+        assert_se(sd_dhcp_lease_get_address(lease, &addr) >= 0);
+        assert_se(memcmp(&addr.s_addr, &test_addr_acq_ack[44],
+                      sizeof(addr.s_addr)) == 0);
+
+        assert_se(sd_dhcp_lease_get_netmask(lease, &addr) >= 0);
+        assert_se(memcmp(&addr.s_addr, &test_addr_acq_ack[285],
+                      sizeof(addr.s_addr)) == 0);
+
+        assert_se(sd_dhcp_lease_get_router(lease, &addrs) == 1);
+        assert_se(memcmp(&addrs[0].s_addr, &test_addr_acq_ack[308],
+                         sizeof(addrs[0].s_addr)) == 0);
+
+        if (verbose)
+                printf("  DHCP address acquired\n");
+
+        sd_event_exit(e, 0);
+
+        return 0;
+}
+
+static int test_addr_acq_recv_request(size_t size, DHCPMessage *request) {
+        uint16_t udp_check = 0;
+        uint8_t *msg_bytes = (uint8_t *)request;
+        int res;
+
+        res = dhcp_option_parse(request, size, check_options, NULL, NULL);
+        assert_se(res == DHCP_REQUEST);
+        assert_se(xid == request->xid);
+
+        assert_se(msg_bytes[size - 1] == SD_DHCP_OPTION_END);
+
+        if (verbose)
+                printf("  recv DHCP Request  0x%08x\n", be32toh(xid));
+
+        memcpy(&test_addr_acq_ack[26], &udp_check, sizeof(udp_check));
+        memcpy(&test_addr_acq_ack[32], &xid, sizeof(xid));
+        memcpy(&test_addr_acq_ack[56], &mac_addr, ETHER_ADDR_LEN);
+
+        callback_recv = NULL;
+
+        res = write(test_fd[1], test_addr_acq_ack,
+                    sizeof(test_addr_acq_ack));
+        assert_se(res == sizeof(test_addr_acq_ack));
+
+        if (verbose)
+                printf("  send DHCP Ack\n");
+
+        return 0;
+};
+
+static int test_addr_acq_recv_discover(size_t size, DHCPMessage *discover) {
+        uint16_t udp_check = 0;
+        uint8_t *msg_bytes = (uint8_t *)discover;
+        int res;
+
+        res = dhcp_option_parse(discover, size, check_options, NULL, NULL);
+        assert_se(res == DHCP_DISCOVER);
+
+        assert_se(msg_bytes[size - 1] == SD_DHCP_OPTION_END);
+
+        xid = discover->xid;
+
+        if (verbose)
+                printf("  recv DHCP Discover 0x%08x\n", be32toh(xid));
+
+        memcpy(&test_addr_acq_offer[26], &udp_check, sizeof(udp_check));
+        memcpy(&test_addr_acq_offer[32], &xid, sizeof(xid));
+        memcpy(&test_addr_acq_offer[56], &mac_addr, ETHER_ADDR_LEN);
+
+        callback_recv = test_addr_acq_recv_request;
+
+        res = write(test_fd[1], test_addr_acq_offer,
+                    sizeof(test_addr_acq_offer));
+        assert_se(res == sizeof(test_addr_acq_offer));
+
+        if (verbose)
+                printf("  sent DHCP Offer\n");
+
+        return 0;
+}
+
+static void test_addr_acq(sd_event *e) {
+        sd_dhcp_client *client;
+        int res, r;
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        r = sd_dhcp_client_new(&client, false);
+        assert_se(r >= 0);
+        assert_se(client);
+
+        r = sd_dhcp_client_attach_event(client, e, 0);
+        assert_se(r >= 0);
+
+        assert_se(sd_dhcp_client_set_ifindex(client, 42) >= 0);
+        assert_se(sd_dhcp_client_set_mac(client, mac_addr, bcast_addr, ETH_ALEN, ARPHRD_ETHER) >= 0);
+
+        assert_se(sd_dhcp_client_set_callback(client, test_addr_acq_acquired, e) >= 0);
+
+        callback_recv = test_addr_acq_recv_discover;
+
+        assert_se(sd_event_add_time_relative(
+                                  e, &test_hangcheck,
+                                  clock_boottime_or_monotonic(),
+                                  2 * USEC_PER_SEC, 0,
+                                  test_dhcp_hangcheck, NULL) >= 0);
+
+        res = sd_dhcp_client_start(client);
+        assert_se(IN_SET(res, 0, -EINPROGRESS));
+
+        assert_se(sd_event_loop(e) >= 0);
+
+        test_hangcheck = sd_event_source_unref(test_hangcheck);
+
+        assert_se(sd_dhcp_client_set_callback(client, NULL, NULL) >= 0);
+        assert_se(sd_dhcp_client_stop(client) >= 0);
+        sd_dhcp_client_unref(client);
+
+        test_fd[1] = safe_close(test_fd[1]);
+
+        callback_recv = NULL;
+        xid = 0;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *e;
+
+        test_setup_logging(LOG_DEBUG);
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        test_request_basic(e);
+        test_request_anonymize(e);
+        test_checksum();
+        test_dhcp_identifier_set_iaid();
+
+        test_discover_message(e);
+        test_addr_acq(e);
+
+#if VALGRIND
+        /* Make sure the async_close thread has finished.
+         * valgrind would report some of the phread_* structures
+         * as not cleaned up properly. */
+        sleep(1);
+#endif
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-dhcp-option.c b/src/libsystemd-network/test-dhcp-option.c
new file mode 100644
index 0000000..1eebe3a
--- /dev/null
+++ b/src/libsystemd-network/test-dhcp-option.c
@@ -0,0 +1,370 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <net/if_arp.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "alloc-util.h"
+#include "dhcp-internal.h"
+#include "dhcp-protocol.h"
+#include "macro.h"
+#include "memory-util.h"
+
+struct option_desc {
+        uint8_t sname[64];
+        int snamelen;
+        uint8_t file[128];
+        int filelen;
+        uint8_t options[128];
+        int len;
+        bool success;
+        int filepos;
+        int snamepos;
+        int pos;
+};
+
+static bool verbose = false;
+
+static struct option_desc option_tests[] = {
+        { {}, 0, {}, 0, { 42, 5, 65, 66, 67, 68, 69 }, 7, false, },
+        { {}, 0, {}, 0, { 42, 5, 65, 66, 67, 68, 69, 0, 0,
+                          SD_DHCP_OPTION_MESSAGE_TYPE, 1, DHCP_ACK }, 12, true, },
+        { {}, 0, {}, 0, { 8, 255, 70, 71, 72 }, 5, false, },
+        { {}, 0, {}, 0, { 0x35, 0x01, 0x05, 0x36, 0x04, 0x01, 0x00, 0xa8,
+                          0xc0, 0x33, 0x04, 0x00, 0x01, 0x51, 0x80, 0x01,
+                          0x04, 0xff, 0xff, 0xff, 0x00, 0x03, 0x04, 0xc0,
+                          0xa8, 0x00, 0x01, 0x06, 0x04, 0xc0, 0xa8, 0x00,
+                          0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, },
+          40, true, },
+        { {}, 0, {}, 0, { SD_DHCP_OPTION_MESSAGE_TYPE, 1, DHCP_OFFER,
+                          42, 3, 0, 0, 0 }, 8, true, },
+        { {}, 0, {}, 0, { 42, 2, 1, 2, 44 }, 5, false, },
+
+        { {}, 0,
+          { 222, 3, 1, 2, 3, SD_DHCP_OPTION_MESSAGE_TYPE, 1, DHCP_NAK }, 8,
+          { SD_DHCP_OPTION_OVERLOAD, 1, DHCP_OVERLOAD_FILE }, 3, true, },
+
+        { { 1, 4, 1, 2, 3, 4, SD_DHCP_OPTION_MESSAGE_TYPE, 1, DHCP_ACK }, 9,
+          { 222, 3, 1, 2, 3 }, 5,
+          { SD_DHCP_OPTION_OVERLOAD, 1,
+            DHCP_OVERLOAD_FILE|DHCP_OVERLOAD_SNAME }, 3, true, },
+};
+
+static const char *dhcp_type(int type) {
+        switch(type) {
+        case DHCP_DISCOVER:
+                return "DHCPDISCOVER";
+        case DHCP_OFFER:
+                return "DHCPOFFER";
+        case DHCP_REQUEST:
+                return "DHCPREQUEST";
+        case DHCP_DECLINE:
+                return "DHCPDECLINE";
+        case DHCP_ACK:
+                return "DHCPACK";
+        case DHCP_NAK:
+                return "DHCPNAK";
+        case DHCP_RELEASE:
+                return "DHCPRELEASE";
+        default:
+                return "unknown";
+        }
+}
+
+static void test_invalid_buffer_length(void) {
+        DHCPMessage message;
+
+        assert_se(dhcp_option_parse(&message, 0, NULL, NULL, NULL) == -EINVAL);
+        assert_se(dhcp_option_parse(&message, sizeof(DHCPMessage) - 1, NULL, NULL, NULL) == -EINVAL);
+}
+
+static void test_message_init(void) {
+        _cleanup_free_ DHCPMessage *message = NULL;
+        size_t optlen = 4, optoffset;
+        size_t len = sizeof(DHCPMessage) + optlen;
+        uint8_t *magic;
+
+        message = malloc0(len);
+
+        assert_se(dhcp_message_init(message, BOOTREQUEST, 0x12345678,
+                  DHCP_DISCOVER, ARPHRD_ETHER, optlen, &optoffset) >= 0);
+
+        assert_se(message->xid == htobe32(0x12345678));
+        assert_se(message->op == BOOTREQUEST);
+
+        magic = (uint8_t*)&message->magic;
+
+        assert_se(magic[0] == 99);
+        assert_se(magic[1] == 130);
+        assert_se(magic[2] == 83);
+        assert_se(magic[3] == 99);
+
+        assert_se(dhcp_option_parse(message, len, NULL, NULL, NULL) >= 0);
+}
+
+static DHCPMessage *create_message(uint8_t *options, uint16_t optlen,
+                uint8_t *file, uint8_t filelen,
+                uint8_t *sname, uint8_t snamelen) {
+        DHCPMessage *message;
+        size_t len = sizeof(DHCPMessage) + optlen;
+
+        message = malloc0(len);
+        assert_se(message);
+
+        memcpy_safe(&message->options, options, optlen);
+        memcpy_safe(&message->file, file, filelen);
+        memcpy_safe(&message->sname, sname, snamelen);
+
+        return message;
+}
+
+static void test_ignore_opts(uint8_t *descoption, int *descpos, int *desclen) {
+        assert(*descpos >= 0);
+
+        while (*descpos < *desclen) {
+                switch(descoption[*descpos]) {
+                case SD_DHCP_OPTION_PAD:
+                        *descpos += 1;
+                        break;
+
+                case SD_DHCP_OPTION_MESSAGE_TYPE:
+                case SD_DHCP_OPTION_OVERLOAD:
+                        *descpos += 3;
+                        break;
+
+                default:
+                        return;
+                }
+        }
+}
+
+static int test_options_cb(uint8_t code, uint8_t len, const void *option, void *userdata) {
+        struct option_desc *desc = userdata;
+        uint8_t *descoption = NULL;
+        int *desclen = NULL, *descpos = NULL;
+        uint8_t optcode = 0;
+        uint8_t optlen = 0;
+        uint8_t i;
+
+        assert_se((!desc && !code && !len) || desc);
+
+        if (!desc)
+                return -EINVAL;
+
+        assert_se(code != SD_DHCP_OPTION_PAD);
+        assert_se(code != SD_DHCP_OPTION_END);
+        assert_se(code != SD_DHCP_OPTION_MESSAGE_TYPE);
+        assert_se(code != SD_DHCP_OPTION_OVERLOAD);
+
+        while (desc->pos >= 0 || desc->filepos >= 0 || desc->snamepos >= 0) {
+
+                if (desc->pos >= 0) {
+                        descoption = &desc->options[0];
+                        desclen = &desc->len;
+                        descpos = &desc->pos;
+                } else if (desc->filepos >= 0) {
+                        descoption = &desc->file[0];
+                        desclen = &desc->filelen;
+                        descpos = &desc->filepos;
+                } else if (desc->snamepos >= 0) {
+                        descoption = &desc->sname[0];
+                        desclen = &desc->snamelen;
+                        descpos = &desc->snamepos;
+                }
+
+                assert_se(descoption && desclen && descpos);
+
+                if (*desclen)
+                        test_ignore_opts(descoption, descpos, desclen);
+
+                if (*descpos < *desclen)
+                        break;
+
+                if (*descpos == *desclen)
+                        *descpos = -1;
+        }
+
+        assert_se(descpos);
+        assert_se(*descpos != -1);
+
+        optcode = descoption[*descpos];
+        optlen = descoption[*descpos + 1];
+
+        if (verbose)
+                printf("DHCP code %2d(%2d) len %2d(%2d) ", code, optcode,
+                                len, optlen);
+
+        assert_se(code == optcode);
+        assert_se(len == optlen);
+
+        for (i = 0; i < len; i++) {
+
+                if (verbose)
+                        printf("0x%02x(0x%02x) ", ((uint8_t*) option)[i],
+                                        descoption[*descpos + 2 + i]);
+
+                assert_se(((uint8_t*) option)[i] == descoption[*descpos + 2 + i]);
+        }
+
+        if (verbose)
+                printf("\n");
+
+        *descpos += optlen + 2;
+
+        test_ignore_opts(descoption, descpos, desclen);
+
+        if (desc->pos != -1 && desc->pos == desc->len)
+                desc->pos = -1;
+
+        if (desc->filepos != -1 && desc->filepos == desc->filelen)
+                desc->filepos = -1;
+
+        if (desc->snamepos != -1 && desc->snamepos == desc->snamelen)
+                desc->snamepos = -1;
+
+        return 0;
+}
+
+static void test_options(struct option_desc *desc) {
+        uint8_t *options = NULL;
+        uint8_t *file = NULL;
+        uint8_t *sname = NULL;
+        int optlen = 0;
+        int filelen = 0;
+        int snamelen = 0;
+        int buflen = 0;
+        _cleanup_free_ DHCPMessage *message = NULL;
+        int res;
+
+        if (desc) {
+                file = &desc->file[0];
+                filelen = desc->filelen;
+                if (!filelen)
+                        desc->filepos = -1;
+
+                sname = &desc->sname[0];
+                snamelen = desc->snamelen;
+                if (!snamelen)
+                        desc->snamepos = -1;
+
+                options = &desc->options[0];
+                optlen = desc->len;
+                desc->pos = 0;
+        }
+        message = create_message(options, optlen, file, filelen,
+                                 sname, snamelen);
+
+        buflen = sizeof(DHCPMessage) + optlen;
+
+        if (!desc) {
+                assert_se((res = dhcp_option_parse(message, buflen, test_options_cb, NULL, NULL)) == -ENOMSG);
+        } else if (desc->success) {
+                assert_se((res = dhcp_option_parse(message, buflen, test_options_cb, desc, NULL)) >= 0);
+                assert_se(desc->pos == -1 && desc->filepos == -1 && desc->snamepos == -1);
+        } else
+                assert_se((res = dhcp_option_parse(message, buflen, test_options_cb, desc, NULL)) < 0);
+
+        if (verbose)
+                printf("DHCP type %s\n", dhcp_type(res));
+}
+
+static uint8_t options[64] = {
+        'A', 'B', 'C', 'D',
+        160, 2, 0x11, 0x12,
+        0,
+        31, 8, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
+        0,
+        55, 3, 0x51, 0x52, 0x53,
+        17, 7, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+        255
+};
+
+static void test_option_set(void) {
+        _cleanup_free_ DHCPMessage *result = NULL;
+        size_t offset = 0, len, pos;
+        unsigned i;
+
+        result = malloc0(sizeof(DHCPMessage) + 11);
+        assert_se(result);
+
+        result->options[0] = 'A';
+        result->options[1] = 'B';
+        result->options[2] = 'C';
+        result->options[3] = 'D';
+
+        assert_se(dhcp_option_append(result, 0, &offset, 0, SD_DHCP_OPTION_PAD,
+                                     0, NULL) == -ENOBUFS);
+        assert_se(offset == 0);
+
+        offset = 4;
+        assert_se(dhcp_option_append(result, 5, &offset, 0, SD_DHCP_OPTION_PAD,
+                                     0, NULL) == -ENOBUFS);
+        assert_se(offset == 4);
+        assert_se(dhcp_option_append(result, 6, &offset, 0, SD_DHCP_OPTION_PAD,
+                                     0, NULL) >= 0);
+        assert_se(offset == 5);
+
+        offset = pos = 4;
+        len = 11;
+        while (pos < len && options[pos] != SD_DHCP_OPTION_END) {
+                assert_se(dhcp_option_append(result, len, &offset, DHCP_OVERLOAD_SNAME,
+                                             options[pos],
+                                             options[pos + 1],
+                                             &options[pos + 2]) >= 0);
+
+                if (options[pos] == SD_DHCP_OPTION_PAD)
+                        pos++;
+                else
+                        pos += 2 + options[pos + 1];
+
+                if (pos < len)
+                        assert_se(offset == pos);
+        }
+
+        for (i = 0; i < 9; i++) {
+                if (verbose)
+                        printf("%2u: 0x%02x(0x%02x) (options)\n", i, result->options[i],
+                               options[i]);
+                assert_se(result->options[i] == options[i]);
+        }
+
+        if (verbose)
+                printf("%2d: 0x%02x(0x%02x) (options)\n", 9, result->options[9],
+                       SD_DHCP_OPTION_END);
+
+        assert_se(result->options[9] == SD_DHCP_OPTION_END);
+
+        if (verbose)
+                printf("%2d: 0x%02x(0x%02x) (options)\n", 10, result->options[10],
+                       SD_DHCP_OPTION_PAD);
+
+        assert_se(result->options[10] == SD_DHCP_OPTION_PAD);
+
+        for (i = 0; i < pos - 8; i++) {
+                if (verbose)
+                        printf("%2u: 0x%02x(0x%02x) (sname)\n", i, result->sname[i],
+                               options[i + 9]);
+                assert_se(result->sname[i] == options[i + 9]);
+        }
+
+        if (verbose)
+                printf ("\n");
+}
+
+int main(int argc, char *argv[]) {
+        unsigned i;
+
+        test_invalid_buffer_length();
+        test_message_init();
+
+        test_options(NULL);
+
+        for (i = 0; i < ELEMENTSOF(option_tests); i++)
+                test_options(&option_tests[i]);
+
+        test_option_set();
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-dhcp-server.c b/src/libsystemd-network/test-dhcp-server.c
new file mode 100644
index 0000000..e91b440
--- /dev/null
+++ b/src/libsystemd-network/test-dhcp-server.c
@@ -0,0 +1,245 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <net/if_arp.h>
+
+#include "sd-dhcp-server.h"
+#include "sd-event.h"
+
+#include "dhcp-server-internal.h"
+#include "tests.h"
+
+static void test_pool(struct in_addr *address, unsigned size, int ret) {
+        _cleanup_(sd_dhcp_server_unrefp) sd_dhcp_server *server = NULL;
+
+        assert_se(sd_dhcp_server_new(&server, 1) >= 0);
+
+        assert_se(sd_dhcp_server_configure_pool(server, address, 8, 0, size) == ret);
+}
+
+static int test_basic(sd_event *event) {
+        _cleanup_(sd_dhcp_server_unrefp) sd_dhcp_server *server = NULL;
+        struct in_addr address_lo = {
+                .s_addr = htobe32(INADDR_LOOPBACK),
+        };
+        struct in_addr address_any = {
+                .s_addr = htobe32(INADDR_ANY),
+        };
+        int r;
+
+        /* attach to loopback interface */
+        assert_se(sd_dhcp_server_new(&server, 1) >= 0);
+        assert_se(server);
+
+        assert_se(sd_dhcp_server_attach_event(server, event, 0) >= 0);
+        assert_se(sd_dhcp_server_attach_event(server, event, 0) == -EBUSY);
+        assert_se(sd_dhcp_server_get_event(server) == event);
+        assert_se(sd_dhcp_server_detach_event(server) >= 0);
+        assert_se(!sd_dhcp_server_get_event(server));
+        assert_se(sd_dhcp_server_attach_event(server, NULL, 0) >= 0);
+        assert_se(sd_dhcp_server_attach_event(server, NULL, 0) == -EBUSY);
+
+        assert_se(sd_dhcp_server_ref(server) == server);
+        assert_se(!sd_dhcp_server_unref(server));
+
+        assert_se(sd_dhcp_server_start(server) == -EUNATCH);
+
+        assert_se(sd_dhcp_server_configure_pool(server, &address_any, 28, 0, 0) == -EINVAL);
+        assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 38, 0, 0) == -ERANGE);
+        assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 8, 0, 0) >= 0);
+        assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 8, 0, 0) >= 0);
+
+        test_pool(&address_any, 1, -EINVAL);
+        test_pool(&address_lo, 1, 0);
+
+        r = sd_dhcp_server_start(server);
+        if (r == -EPERM)
+                return log_info_errno(r, "sd_dhcp_server_start failed: %m");
+        assert_se(r >= 0);
+
+        assert_se(sd_dhcp_server_start(server) == -EBUSY);
+        assert_se(sd_dhcp_server_stop(server) >= 0);
+        assert_se(sd_dhcp_server_stop(server) >= 0);
+        assert_se(sd_dhcp_server_start(server) >= 0);
+
+        return 0;
+}
+
+static void test_message_handler(void) {
+        _cleanup_(sd_dhcp_server_unrefp) sd_dhcp_server *server = NULL;
+        struct {
+                DHCPMessage message;
+                struct {
+                        uint8_t code;
+                        uint8_t length;
+                        uint8_t type;
+                } _packed_ option_type;
+                struct {
+                        uint8_t code;
+                        uint8_t length;
+                        be32_t address;
+                } _packed_ option_requested_ip;
+                struct {
+                        uint8_t code;
+                        uint8_t length;
+                        be32_t address;
+                } _packed_ option_server_id;
+                struct {
+                        uint8_t code;
+                        uint8_t length;
+                        uint8_t id[7];
+                } _packed_ option_client_id;
+                uint8_t end;
+        } _packed_ test = {
+                .message.op = BOOTREQUEST,
+                .message.htype = ARPHRD_ETHER,
+                .message.hlen = ETHER_ADDR_LEN,
+                .message.xid = htobe32(0x12345678),
+                .message.chaddr = { 'A', 'B', 'C', 'D', 'E', 'F' },
+                .option_type.code = SD_DHCP_OPTION_MESSAGE_TYPE,
+                .option_type.length = 1,
+                .option_type.type = DHCP_DISCOVER,
+                .end = SD_DHCP_OPTION_END,
+        };
+        struct in_addr address_lo = {
+                .s_addr = htobe32(INADDR_LOOPBACK),
+        };
+
+        assert_se(sd_dhcp_server_new(&server, 1) >= 0);
+        assert_se(sd_dhcp_server_configure_pool(server, &address_lo, 8, 0, 0) >= 0);
+        assert_se(sd_dhcp_server_attach_event(server, NULL, 0) >= 0);
+        assert_se(sd_dhcp_server_start(server) >= 0);
+
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+
+        test.end = 0;
+        /* TODO, shouldn't this fail? */
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+        test.end = SD_DHCP_OPTION_END;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+
+        test.option_type.code = 0;
+        test.option_type.length = 0;
+        test.option_type.type = 0;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.option_type.code = SD_DHCP_OPTION_MESSAGE_TYPE;
+        test.option_type.length = 1;
+        test.option_type.type = DHCP_DISCOVER;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+
+        test.message.op = 0;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.message.op = BOOTREQUEST;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+
+        test.message.htype = 0;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.message.htype = ARPHRD_ETHER;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+
+        test.message.hlen = 0;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.message.hlen = ETHER_ADDR_LEN;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
+
+        test.option_type.type = DHCP_REQUEST;
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.option_requested_ip.code = SD_DHCP_OPTION_REQUESTED_IP_ADDRESS;
+        test.option_requested_ip.length = 4;
+        test.option_requested_ip.address = htobe32(0x12345678);
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_NAK);
+        test.option_server_id.code = SD_DHCP_OPTION_SERVER_IDENTIFIER;
+        test.option_server_id.length = 4;
+        test.option_server_id.address = htobe32(INADDR_LOOPBACK);
+        test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 3);
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_ACK);
+
+        test.option_server_id.address = htobe32(0x12345678);
+        test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 3);
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.option_server_id.address = htobe32(INADDR_LOOPBACK);
+        test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 4);
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+        test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 3);
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_ACK);
+
+        test.option_client_id.code = SD_DHCP_OPTION_CLIENT_IDENTIFIER;
+        test.option_client_id.length = 7;
+        test.option_client_id.id[0] = 0x01;
+        test.option_client_id.id[1] = 'A';
+        test.option_client_id.id[2] = 'B';
+        test.option_client_id.id[3] = 'C';
+        test.option_client_id.id[4] = 'D';
+        test.option_client_id.id[5] = 'E';
+        test.option_client_id.id[6] = 'F';
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_ACK);
+
+        test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 30);
+        assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
+}
+
+static uint64_t client_id_hash_helper(DHCPClientId *id, uint8_t key[HASH_KEY_SIZE]) {
+        struct siphash state;
+
+        siphash24_init(&state, key);
+        client_id_hash_func(id, &state);
+
+        return htole64(siphash24_finalize(&state));
+}
+
+static void test_client_id_hash(void) {
+        DHCPClientId a = {
+                .length = 4,
+        }, b = {
+                .length = 4,
+        };
+        uint8_t hash_key[HASH_KEY_SIZE] = {
+                '0', '1', '2', '3', '4', '5', '6', '7',
+                '8', '9', 'A', 'B', 'C', 'D', 'E', 'F',
+        };
+
+        a.data = (uint8_t*)strdup("abcd");
+        b.data = (uint8_t*)strdup("abcd");
+
+        assert_se(client_id_compare_func(&a, &b) == 0);
+        assert_se(client_id_hash_helper(&a, hash_key) == client_id_hash_helper(&b, hash_key));
+        a.length = 3;
+        assert_se(client_id_compare_func(&a, &b) != 0);
+        a.length = 4;
+        assert_se(client_id_compare_func(&a, &b) == 0);
+        assert_se(client_id_hash_helper(&a, hash_key) == client_id_hash_helper(&b, hash_key));
+
+        b.length = 3;
+        assert_se(client_id_compare_func(&a, &b) != 0);
+        b.length = 4;
+        assert_se(client_id_compare_func(&a, &b) == 0);
+        assert_se(client_id_hash_helper(&a, hash_key) == client_id_hash_helper(&b, hash_key));
+
+        free(b.data);
+        b.data = (uint8_t*)strdup("abce");
+        assert_se(client_id_compare_func(&a, &b) != 0);
+
+        free(a.data);
+        free(b.data);
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *e;
+        int r;
+
+        test_setup_logging(LOG_DEBUG);
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        r = test_basic(e);
+        if (r != 0)
+                return log_tests_skipped("cannot start dhcp server");
+
+        test_message_handler();
+        test_client_id_hash();
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-dhcp6-client.c b/src/libsystemd-network/test-dhcp6-client.c
new file mode 100644
index 0000000..e6a43dc
--- /dev/null
+++ b/src/libsystemd-network/test-dhcp6-client.c
@@ -0,0 +1,1004 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <net/ethernet.h>
+#include <net/if_arp.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "sd-dhcp6-client.h"
+#include "sd-event.h"
+
+#include "dhcp6-internal.h"
+#include "dhcp6-lease-internal.h"
+#include "dhcp6-protocol.h"
+#include "fd-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "tests.h"
+#include "time-util.h"
+#include "virt.h"
+
+static struct ether_addr mac_addr = {
+        .ether_addr_octet = {'A', 'B', 'C', '1', '2', '3'}
+};
+
+static sd_event_source *hangcheck;
+static int test_dhcp_fd[2];
+static int test_ifindex = 42;
+static int test_client_message_num;
+static be32_t test_iaid = 0;
+static uint8_t test_duid[14] = { };
+
+static int test_client_basic(sd_event *e) {
+        sd_dhcp6_client *client;
+        int v;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(sd_dhcp6_client_new(&client) >= 0);
+        assert_se(client);
+
+        assert_se(sd_dhcp6_client_attach_event(client, e, 0) >= 0);
+
+        assert_se(sd_dhcp6_client_set_ifindex(client, 15) == 0);
+        assert_se(sd_dhcp6_client_set_ifindex(client, -42) == -EINVAL);
+        assert_se(sd_dhcp6_client_set_ifindex(client, -1) == -EINVAL);
+        assert_se(sd_dhcp6_client_set_ifindex(client, 42) >= 0);
+
+        assert_se(sd_dhcp6_client_set_mac(client, (const uint8_t *) &mac_addr,
+                                          sizeof (mac_addr),
+                                          ARPHRD_ETHER) >= 0);
+
+        assert_se(sd_dhcp6_client_set_fqdn(client, "host") == 1);
+        assert_se(sd_dhcp6_client_set_fqdn(client, "host.domain") == 1);
+        assert_se(sd_dhcp6_client_set_fqdn(client, NULL) == 1);
+        assert_se(sd_dhcp6_client_set_fqdn(client, "~host") == -EINVAL);
+        assert_se(sd_dhcp6_client_set_fqdn(client, "~host.domain") == -EINVAL);
+
+        assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_CLIENTID) == 0);
+        assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_DNS_SERVERS) == -EEXIST);
+        assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_NTP_SERVER) == -EEXIST);
+        assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_SNTP_SERVERS) == -EEXIST);
+        assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_DOMAIN_LIST) == -EEXIST);
+        assert_se(sd_dhcp6_client_set_request_option(client, 10) == 0);
+
+        assert_se(sd_dhcp6_client_set_information_request(client, 1) >= 0);
+        v = 0;
+        assert_se(sd_dhcp6_client_get_information_request(client, &v) >= 0);
+        assert_se(v);
+        assert_se(sd_dhcp6_client_set_information_request(client, 0) >= 0);
+        v = 42;
+        assert_se(sd_dhcp6_client_get_information_request(client, &v) >= 0);
+        assert_se(v == 0);
+
+        v = 0;
+        assert_se(sd_dhcp6_client_get_address_request(client, &v) >= 0);
+        assert_se(v);
+        v = 0;
+        assert_se(sd_dhcp6_client_set_address_request(client, 1) >= 0);
+        assert_se(sd_dhcp6_client_get_address_request(client, &v) >= 0);
+        assert_se(v);
+        v = 42;
+        assert_se(sd_dhcp6_client_set_address_request(client, 1) >= 0);
+        assert_se(sd_dhcp6_client_get_address_request(client, &v) >= 0);
+        assert_se(v);
+
+        assert_se(sd_dhcp6_client_set_address_request(client, 1) >= 0);
+        assert_se(sd_dhcp6_client_set_prefix_delegation(client, 1) >= 0);
+        v = 0;
+        assert_se(sd_dhcp6_client_get_address_request(client, &v) >= 0);
+        assert_se(v);
+        v = 0;
+        assert_se(sd_dhcp6_client_get_prefix_delegation(client, &v) >= 0);
+        assert_se(v);
+
+        assert_se(sd_dhcp6_client_set_callback(client, NULL, NULL) >= 0);
+
+        assert_se(sd_dhcp6_client_detach_event(client) >= 0);
+        assert_se(!sd_dhcp6_client_unref(client));
+
+        return 0;
+}
+
+static int test_parse_domain(sd_event *e) {
+        uint8_t *data;
+        char *domain;
+        char **list;
+        int r;
+
+        log_debug("/* %s */", __func__);
+
+        data = (uint8_t []) { 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0 };
+        r = dhcp6_option_parse_domainname(data, 13, &domain);
+        assert_se(r == 0);
+        assert_se(domain);
+        assert_se(streq(domain, "example.com"));
+        free(domain);
+
+        data = (uint8_t []) { 4, 't', 'e', 's', 't' };
+        r = dhcp6_option_parse_domainname(data, 5, &domain);
+        assert_se(r == 0);
+        assert_se(domain);
+        assert_se(streq(domain, "test"));
+        free(domain);
+
+        data = (uint8_t []) { 0 };
+        r = dhcp6_option_parse_domainname(data, 1, &domain);
+        assert_se(r < 0);
+
+        data = (uint8_t []) { 7, 'e', 'x', 'a', 'm', 'p', 'l', 'e', 3, 'c', 'o', 'm', 0,
+                              6, 'f', 'o', 'o', 'b', 'a', 'r', 0 };
+        r = dhcp6_option_parse_domainname_list(data, 21, &list);
+        assert_se(r == 2);
+        assert_se(list);
+        assert_se(streq(list[0], "example.com"));
+        assert_se(streq(list[1], "foobar"));
+        strv_free(list);
+
+        data = (uint8_t []) { 1, 'a', 0, 20, 'b', 'c' };
+        r = dhcp6_option_parse_domainname_list(data, 6, &list);
+        assert_se(r < 0);
+
+        data = (uint8_t []) { 0 , 0 };
+        r = dhcp6_option_parse_domainname_list(data, 2, &list);
+        assert_se(r < 0);
+
+        return 0;
+}
+
+static int test_option(sd_event *e) {
+        uint8_t packet[] = {
+                'F', 'O', 'O',
+                0x00, SD_DHCP6_OPTION_ORO, 0x00, 0x07,
+                'A', 'B', 'C', 'D', 'E', 'F', 'G',
+                0x00, SD_DHCP6_OPTION_VENDOR_CLASS, 0x00, 0x09,
+                '1', '2', '3', '4', '5', '6', '7', '8', '9',
+                'B', 'A', 'R',
+        };
+        uint8_t result[] = {
+                'F', 'O', 'O',
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                'B', 'A', 'R',
+        };
+        uint16_t optcode;
+        size_t optlen;
+        uint8_t *optval, *buf, *out;
+        size_t zero = 0, pos = 3;
+        size_t buflen = sizeof(packet), outlen = sizeof(result);
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(buflen == outlen);
+
+        assert_se(dhcp6_option_parse(&buf, &zero, &optcode, &optlen,
+                                     &optval) == -ENOMSG);
+
+        buflen -= 3;
+        buf = &packet[3];
+        outlen -= 3;
+        out = &result[3];
+
+        assert_se(dhcp6_option_parse(&buf, &buflen, &optcode, &optlen,
+                                     &optval) >= 0);
+        pos += 4 + optlen;
+        assert_se(buf == &packet[pos]);
+        assert_se(optcode == SD_DHCP6_OPTION_ORO);
+        assert_se(optlen == 7);
+        assert_se(buflen + pos == sizeof(packet));
+
+        assert_se(dhcp6_option_append(&out, &outlen, optcode, optlen,
+                                      optval) >= 0);
+        assert_se(out == &result[pos]);
+        assert_se(*out == 0x00);
+
+        assert_se(dhcp6_option_parse(&buf, &buflen, &optcode, &optlen,
+                                     &optval) >= 0);
+        pos += 4 + optlen;
+        assert_se(buf == &packet[pos]);
+        assert_se(optcode == SD_DHCP6_OPTION_VENDOR_CLASS);
+        assert_se(optlen == 9);
+        assert_se(buflen + pos == sizeof(packet));
+
+        assert_se(dhcp6_option_append(&out, &outlen, optcode, optlen,
+                                      optval) >= 0);
+        assert_se(out == &result[pos]);
+        assert_se(*out == 'B');
+
+        assert_se(memcmp(packet, result, sizeof(packet)) == 0);
+
+        return 0;
+}
+
+static int test_option_status(sd_event *e) {
+        uint8_t option1[] = {
+                /* IA NA */
+                0x00, 0x03, 0x00, 0x12, 0x1a, 0x1d, 0x1a, 0x1d,
+                0x00, 0x01, 0x00, 0x01, 0x00, 0x02, 0x00, 0x02,
+                /* status option */
+                0x00, 0x0d, 0x00, 0x02, 0x00, 0x01,
+        };
+        static const uint8_t option2[] = {
+                /* IA NA */
+                0x00, 0x03, 0x00, 0x2e, 0x1a, 0x1d, 0x1a, 0x1d,
+                0x00, 0x01, 0x00, 0x01, 0x00, 0x02, 0x00, 0x02,
+                /* IA Addr */
+                0x00, 0x05, 0x00, 0x1e,
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+                0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
+                0x01, 0x02, 0x03, 0x04, 0x0a, 0x0b, 0x0c, 0x0d,
+                /* status option */
+                0x00, 0x0d, 0x00, 0x02, 0x00, 0x01,
+        };
+        static const uint8_t option3[] = {
+                /* IA NA */
+                0x00, 0x03, 0x00, 0x34, 0x1a, 0x1d, 0x1a, 0x1d,
+                0x00, 0x01, 0x00, 0x01, 0x00, 0x02, 0x00, 0x02,
+                /* IA Addr */
+                0x00, 0x05, 0x00, 0x24,
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+                0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
+                0x01, 0x02, 0x03, 0x04, 0x0a, 0x0b, 0x0c, 0x0d,
+                /* status option */
+                0x00, 0x0d, 0x00, 0x08, 0x00, 0x00, 'f',  'o',
+                'o',  'b',  'a',  'r',
+        };
+        static const uint8_t option4[] = {
+                /* IA PD */
+                0x00, 0x19, 0x00, 0x2f, 0x1a, 0x1d, 0x1a, 0x1d,
+                0x00, 0x01, 0x00, 0x01, 0x00, 0x02, 0x00, 0x02,
+                /* IA PD Prefix */
+                0x00, 0x1a, 0x00, 0x1f,
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+                0x80, 0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe,
+                0xef, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x00,
+                /* status option */
+                0x00, 0x0d, 0x00, 0x02, 0x00, 0x00,
+        };
+        static const uint8_t option5[] = {
+                /* IA PD */
+                0x00, 0x19, 0x00, 0x52, 0x1a, 0x1d, 0x1a, 0x1d,
+                0x00, 0x01, 0x00, 0x01, 0x00, 0x02, 0x00, 0x02,
+                /* IA PD Prefix #1 */
+                0x00, 0x1a, 0x00, 0x1f,
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+                0x80, 0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe,
+                0xef, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x00,
+                /* status option */
+                0x00, 0x0d, 0x00, 0x02, 0x00, 0x00,
+                /* IA PD Prefix #2 */
+                0x00, 0x1a, 0x00, 0x1f,
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+                0x80, 0x20, 0x01, 0x0d, 0xb8, 0xc0, 0x0l, 0xd0,
+                0x0d, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x00,
+                0x00, 0x0d, 0x00, 0x02, 0x00, 0x00,
+        };
+        DHCP6Option *option;
+        DHCP6IA ia, pd;
+        int r = 0;
+
+        log_debug("/* %s */", __func__);
+
+        zero(ia);
+        option = (DHCP6Option *)option1;
+        assert_se(sizeof(option1) == sizeof(DHCP6Option) + be16toh(option->len));
+
+        r = dhcp6_option_parse_ia(option, &ia, NULL);
+        assert_se(r == 0);
+        assert_se(ia.addresses == NULL);
+
+        option->len = htobe16(17);
+        r = dhcp6_option_parse_ia(option, &ia, NULL);
+        assert_se(r == -ENOBUFS);
+        assert_se(ia.addresses == NULL);
+
+        option->len = htobe16(sizeof(DHCP6Option));
+        r = dhcp6_option_parse_ia(option, &ia, NULL);
+        assert_se(r == -ENOBUFS);
+        assert_se(ia.addresses == NULL);
+
+        zero(ia);
+        option = (DHCP6Option *)option2;
+        assert_se(sizeof(option2) == sizeof(DHCP6Option) + be16toh(option->len));
+
+        r = dhcp6_option_parse_ia(option, &ia, NULL);
+        assert_se(r >= 0);
+        assert_se(ia.addresses == NULL);
+
+        zero(ia);
+        option = (DHCP6Option *)option3;
+        assert_se(sizeof(option3) == sizeof(DHCP6Option) + be16toh(option->len));
+
+        r = dhcp6_option_parse_ia(option, &ia, NULL);
+        assert_se(r >= 0);
+        assert_se(ia.addresses != NULL);
+        dhcp6_lease_free_ia(&ia);
+
+        zero(pd);
+        option = (DHCP6Option *)option4;
+        assert_se(sizeof(option4) == sizeof(DHCP6Option) + be16toh(option->len));
+
+        r = dhcp6_option_parse_ia(option, &pd, NULL);
+        assert_se(r >= 0);
+        assert_se(pd.addresses != NULL);
+        assert_se(memcmp(&pd.ia_pd.id, &option4[4], 4) == 0);
+        assert_se(memcmp(&pd.ia_pd.lifetime_t1, &option4[8], 4) == 0);
+        assert_se(memcmp(&pd.ia_pd.lifetime_t2, &option4[12], 4) == 0);
+        dhcp6_lease_free_ia(&pd);
+
+        zero(pd);
+        option = (DHCP6Option *)option5;
+        assert_se(sizeof(option5) == sizeof(DHCP6Option) + be16toh(option->len));
+
+        r = dhcp6_option_parse_ia(option, &pd, NULL);
+        assert_se(r >= 0);
+        assert_se(pd.addresses != NULL);
+        dhcp6_lease_free_ia(&pd);
+
+        return 0;
+}
+
+static uint8_t msg_advertise[198] = {
+        0x02, 0x0f, 0xb4, 0xe5, 0x00, 0x01, 0x00, 0x0e,
+        0x00, 0x01, 0x00, 0x01, 0x1a, 0x6b, 0xf3, 0x30,
+        0x3c, 0x97, 0x0e, 0xcf, 0xa3, 0x7d, 0x00, 0x03,
+        0x00, 0x5e, 0x0e, 0xcf, 0xa3, 0x7d, 0x00, 0x00,
+        0x00, 0x50, 0x00, 0x00, 0x00, 0x78, 0x00, 0x05,
+        0x00, 0x18, 0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad,
+        0xbe, 0xef, 0x78, 0xee, 0x1c, 0xf3, 0x09, 0x3c,
+        0x55, 0xad, 0x00, 0x00, 0x00, 0x96, 0x00, 0x00,
+        0x00, 0xb4, 0x00, 0x0d, 0x00, 0x32, 0x00, 0x00,
+        0x41, 0x64, 0x64, 0x72, 0x65, 0x73, 0x73, 0x28,
+        0x65, 0x73, 0x29, 0x20, 0x72, 0x65, 0x6e, 0x65,
+        0x77, 0x65, 0x64, 0x2e, 0x20, 0x47, 0x72, 0x65,
+        0x65, 0x74, 0x69, 0x6e, 0x67, 0x73, 0x20, 0x66,
+        0x72, 0x6f, 0x6d, 0x20, 0x70, 0x6c, 0x61, 0x6e,
+        0x65, 0x74, 0x20, 0x45, 0x61, 0x72, 0x74, 0x68,
+        0x00, 0x17, 0x00, 0x10, 0x20, 0x01, 0x0d, 0xb8,
+        0xde, 0xad, 0xbe, 0xef, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x01, 0x00, 0x18, 0x00, 0x0b,
+        0x03, 0x6c, 0x61, 0x62, 0x05, 0x69, 0x6e, 0x74,
+        0x72, 0x61, 0x00, 0x00, 0x1f, 0x00, 0x10, 0x20,
+        0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe, 0xef, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00,
+        0x02, 0x00, 0x0e, 0x00, 0x01, 0x00, 0x01, 0x19,
+        0x40, 0x5c, 0x53, 0x78, 0x2b, 0xcb, 0xb3, 0x6d,
+        0x53, 0x00, 0x07, 0x00, 0x01, 0x00
+};
+
+static uint8_t msg_reply[191] = {
+        0x07, 0xf7, 0x4e, 0x57, 0x00, 0x02, 0x00, 0x0e,
+        0x00, 0x01, 0x00, 0x01, 0x19, 0x40, 0x5c, 0x53,
+        0x78, 0x2b, 0xcb, 0xb3, 0x6d, 0x53, 0x00, 0x01,
+        0x00, 0x0e, 0x00, 0x01, 0x00, 0x01, 0x1a, 0x6b,
+        0xf3, 0x30, 0x3c, 0x97, 0x0e, 0xcf, 0xa3, 0x7d,
+        0x00, 0x03, 0x00, 0x4a, 0x0e, 0xcf, 0xa3, 0x7d,
+        0x00, 0x00, 0x00, 0x50, 0x00, 0x00, 0x00, 0x78,
+        0x00, 0x05, 0x00, 0x18, 0x20, 0x01, 0x0d, 0xb8,
+        0xde, 0xad, 0xbe, 0xef, 0x78, 0xee, 0x1c, 0xf3,
+        0x09, 0x3c, 0x55, 0xad, 0x00, 0x00, 0x00, 0x96,
+        0x00, 0x00, 0x00, 0xb4, 0x00, 0x0d, 0x00, 0x1e,
+        0x00, 0x00, 0x41, 0x6c, 0x6c, 0x20, 0x61, 0x64,
+        0x64, 0x72, 0x65, 0x73, 0x73, 0x65, 0x73, 0x20,
+        0x77, 0x65, 0x72, 0x65, 0x20, 0x61, 0x73, 0x73,
+        0x69, 0x67, 0x6e, 0x65, 0x64, 0x2e, 0x00, 0x17,
+        0x00, 0x10, 0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad,
+        0xbe, 0xef, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x01, 0x00, 0x18, 0x00, 0x0b, 0x03, 0x6c,
+        0x61, 0x62, 0x05, 0x69, 0x6e, 0x74, 0x72, 0x61,
+        0x00, 0x00, 0x1f, 0x00, 0x10, 0x20, 0x01, 0x0d,
+        0xb8, 0xde, 0xad, 0xbe, 0xef, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x27, 0x00,
+        0x0e, 0x01, 0x06, 0x63, 0x6c, 0x69, 0x65, 0x6e,
+        0x74, 0x05, 0x69, 0x6e, 0x74, 0x72, 0x61
+};
+
+static uint8_t fqdn_wire[16] = {
+        0x04, 'h', 'o', 's', 't', 0x03, 'l', 'a', 'b',
+        0x05, 'i', 'n', 't', 'r', 'a', 0x00
+};
+
+static int test_advertise_option(sd_event *e) {
+        _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease = NULL;
+        DHCP6Message *advertise = (DHCP6Message *)msg_advertise;
+        size_t len = sizeof(msg_advertise) - sizeof(DHCP6Message), pos = 0;
+        uint32_t lt_pref, lt_valid;
+        bool opt_clientid = false;
+        const struct in6_addr *addrs;
+        uint8_t preference = 255;
+        struct in6_addr addr;
+        char **domains;
+        uint8_t *opt;
+        int r;
+        be32_t val;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(len >= sizeof(DHCP6Message));
+
+        assert_se(dhcp6_lease_new(&lease) >= 0);
+
+        assert_se(advertise->type == DHCP6_ADVERTISE);
+        assert_se((be32toh(advertise->transaction_id) & 0x00ffffff) ==
+                  0x0fb4e5);
+
+        while (pos < len) {
+                DHCP6Option *option = (DHCP6Option *)&advertise->options[pos];
+                const uint16_t optcode = be16toh(option->code);
+                const uint16_t optlen = be16toh(option->len);
+                uint8_t *optval = option->data;
+
+                switch(optcode) {
+                case SD_DHCP6_OPTION_CLIENTID:
+                        assert_se(optlen == 14);
+
+                        opt_clientid = true;
+                        break;
+
+                case SD_DHCP6_OPTION_IA_NA:
+                        assert_se(optlen == 94);
+                        assert_se(!memcmp(optval, &msg_advertise[26], optlen));
+
+                        val = htobe32(0x0ecfa37d);
+                        assert_se(!memcmp(optval, &val, sizeof(val)));
+
+                        val = htobe32(80);
+                        assert_se(!memcmp(optval + 4, &val, sizeof(val)));
+
+                        val = htobe32(120);
+                        assert_se(!memcmp(optval + 8, &val, sizeof(val)));
+
+                        assert_se(dhcp6_option_parse_ia(option, &lease->ia, NULL) >= 0);
+
+                        break;
+
+                case SD_DHCP6_OPTION_SERVERID:
+                        assert_se(optlen == 14);
+                        assert_se(!memcmp(optval, &msg_advertise[179], optlen));
+
+                        assert_se(dhcp6_lease_set_serverid(lease, optval,
+                                                           optlen) >= 0);
+                        break;
+
+                case SD_DHCP6_OPTION_PREFERENCE:
+                        assert_se(optlen == 1);
+                        assert_se(!*optval);
+
+                        assert_se(dhcp6_lease_set_preference(lease,
+                                                             *optval) >= 0);
+                        break;
+
+                case SD_DHCP6_OPTION_ELAPSED_TIME:
+                        assert_se(optlen == 2);
+
+                        break;
+
+                case SD_DHCP6_OPTION_DNS_SERVERS:
+                        assert_se(optlen == 16);
+                        assert_se(dhcp6_lease_set_dns(lease, optval,
+                                                      optlen) >= 0);
+                        break;
+
+                case SD_DHCP6_OPTION_DOMAIN_LIST:
+                        assert_se(optlen == 11);
+                        assert_se(dhcp6_lease_set_domains(lease, optval,
+                                                          optlen) >= 0);
+                        break;
+
+                case SD_DHCP6_OPTION_SNTP_SERVERS:
+                        assert_se(optlen == 16);
+                        assert_se(dhcp6_lease_set_sntp(lease, optval,
+                                                       optlen) >= 0);
+                        break;
+
+                default:
+                        break;
+                }
+
+                pos += sizeof(*option) + optlen;
+        }
+
+        assert_se(pos == len);
+        assert_se(opt_clientid);
+
+        sd_dhcp6_lease_reset_address_iter(lease);
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) >= 0);
+        assert_se(!memcmp(&addr, &msg_advertise[42], sizeof(addr)));
+        assert_se(lt_pref == 150);
+        assert_se(lt_valid == 180);
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) == -ENOMSG);
+
+        sd_dhcp6_lease_reset_address_iter(lease);
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) >= 0);
+        assert_se(!memcmp(&addr, &msg_advertise[42], sizeof(addr)));
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) == -ENOMSG);
+        sd_dhcp6_lease_reset_address_iter(lease);
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) >= 0);
+        assert_se(!memcmp(&addr, &msg_advertise[42], sizeof(addr)));
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) == -ENOMSG);
+
+        assert_se(dhcp6_lease_get_serverid(lease, &opt, &len) >= 0);
+        assert_se(len == 14);
+        assert_se(!memcmp(opt, &msg_advertise[179], len));
+
+        assert_se(dhcp6_lease_get_preference(lease, &preference) >= 0);
+        assert_se(preference == 0);
+
+        r = sd_dhcp6_lease_get_dns(lease, &addrs);
+        assert_se(r == 1);
+        assert_se(!memcmp(addrs, &msg_advertise[124], r * 16));
+
+        r = sd_dhcp6_lease_get_domains(lease, &domains);
+        assert_se(r == 1);
+        assert_se(!strcmp("lab.intra", domains[0]));
+        assert_se(domains[1] == NULL);
+
+        r = sd_dhcp6_lease_get_ntp_addrs(lease, &addrs);
+        assert_se(r == 1);
+        assert_se(!memcmp(addrs, &msg_advertise[159], r * 16));
+
+        return 0;
+}
+
+static int test_hangcheck(sd_event_source *s, uint64_t usec, void *userdata) {
+        assert_not_reached("Test case should have completed in 2 seconds");
+
+        return 0;
+}
+
+static void test_client_solicit_cb(sd_dhcp6_client *client, int event,
+                                   void *userdata) {
+        sd_event *e = userdata;
+        sd_dhcp6_lease *lease;
+        const struct in6_addr *addrs;
+        char **domains;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(e);
+        assert_se(event == SD_DHCP6_CLIENT_EVENT_IP_ACQUIRE);
+
+        assert_se(sd_dhcp6_client_get_lease(client, &lease) >= 0);
+
+        assert_se(sd_dhcp6_lease_get_domains(lease, &domains) == 1);
+        assert_se(!strcmp("lab.intra", domains[0]));
+        assert_se(domains[1] == NULL);
+
+        assert_se(sd_dhcp6_lease_get_dns(lease, &addrs) == 1);
+        assert_se(!memcmp(addrs, &msg_advertise[124], 16));
+
+        assert_se(sd_dhcp6_lease_get_ntp_addrs(lease, &addrs) == 1);
+        assert_se(!memcmp(addrs, &msg_advertise[159], 16));
+
+        assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_DNS_SERVERS) == -EBUSY);
+
+        sd_event_exit(e, 0);
+}
+
+static int test_client_send_reply(DHCP6Message *request) {
+        DHCP6Message reply;
+
+        reply.transaction_id = request->transaction_id;
+        reply.type = DHCP6_REPLY;
+
+        memcpy(msg_reply, &reply.transaction_id, 4);
+
+        memcpy(&msg_reply[26], test_duid, sizeof(test_duid));
+
+        memcpy(&msg_reply[44], &test_iaid, sizeof(test_iaid));
+
+        assert_se(write(test_dhcp_fd[1], msg_reply, sizeof(msg_reply))
+                  == sizeof(msg_reply));
+
+        return 0;
+}
+
+static int test_client_verify_request(DHCP6Message *request, size_t len) {
+        _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease = NULL;
+        bool found_clientid = false, found_iana = false, found_serverid = false,
+                found_elapsed_time = false, found_fqdn = false;
+        uint32_t lt_pref, lt_valid;
+        struct in6_addr addr;
+        size_t pos = 0;
+        be32_t val;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(request->type == DHCP6_REQUEST);
+        assert_se(dhcp6_lease_new(&lease) >= 0);
+
+        len -= sizeof(DHCP6Message);
+
+        while (pos < len) {
+                DHCP6Option *option = (DHCP6Option *)&request->options[pos];
+                uint16_t optcode = be16toh(option->code);
+                uint16_t optlen = be16toh(option->len);
+                uint8_t *optval = option->data;
+
+                switch(optcode) {
+                case SD_DHCP6_OPTION_CLIENTID:
+                        assert_se(!found_clientid);
+                        found_clientid = true;
+
+                        assert_se(!memcmp(optval, &test_duid,
+                                          sizeof(test_duid)));
+
+                        break;
+
+                case SD_DHCP6_OPTION_IA_NA:
+                        assert_se(!found_iana);
+                        found_iana = true;
+
+                        assert_se(optlen == 40);
+                        assert_se(!memcmp(optval, &test_iaid, sizeof(test_iaid)));
+
+                        val = htobe32(80);
+                        assert_se(!memcmp(optval + 4, &val, sizeof(val)));
+
+                        val = htobe32(120);
+                        assert_se(!memcmp(optval + 8, &val, sizeof(val)));
+
+                        assert_se(dhcp6_option_parse_ia(option, &lease->ia, NULL) >= 0);
+
+                        break;
+
+                case SD_DHCP6_OPTION_SERVERID:
+                        assert_se(!found_serverid);
+                        found_serverid = true;
+
+                        assert_se(optlen == 14);
+                        assert_se(!memcmp(&msg_advertise[179], optval, optlen));
+
+                        break;
+
+                case SD_DHCP6_OPTION_ELAPSED_TIME:
+                        assert_se(!found_elapsed_time);
+                        found_elapsed_time = true;
+
+                        assert_se(optlen == 2);
+
+                        break;
+                case SD_DHCP6_OPTION_FQDN:
+                        assert_se(!found_fqdn);
+                        found_fqdn = true;
+
+                        assert_se(optlen == 17);
+
+                        assert_se(optval[0] == 0x01);
+                        assert_se(!memcmp(optval + 1, fqdn_wire, sizeof(fqdn_wire)));
+                        break;
+                }
+
+                pos += sizeof(*option) + optlen;
+        }
+
+        assert_se(found_clientid && found_iana && found_serverid &&
+                  found_elapsed_time);
+
+        sd_dhcp6_lease_reset_address_iter(lease);
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) >= 0);
+        assert_se(!memcmp(&addr, &msg_advertise[42], sizeof(addr)));
+        assert_se(lt_pref == 150);
+        assert_se(lt_valid == 180);
+
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) == -ENOMSG);
+
+        return 0;
+}
+
+static int test_client_send_advertise(DHCP6Message *solicit) {
+        DHCP6Message advertise;
+
+        advertise.transaction_id = solicit->transaction_id;
+        advertise.type = DHCP6_ADVERTISE;
+
+        memcpy(msg_advertise, &advertise.transaction_id, 4);
+
+        memcpy(&msg_advertise[8], test_duid, sizeof(test_duid));
+
+        memcpy(&msg_advertise[26], &test_iaid, sizeof(test_iaid));
+
+        assert_se(write(test_dhcp_fd[1], msg_advertise, sizeof(msg_advertise))
+                  == sizeof(msg_advertise));
+
+        return 0;
+}
+
+static int test_client_verify_solicit(DHCP6Message *solicit, size_t len) {
+        bool found_clientid = false, found_iana = false,
+                found_elapsed_time = false, found_fqdn = false;
+        size_t pos = 0;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(solicit->type == DHCP6_SOLICIT);
+
+        len -= sizeof(DHCP6Message);
+
+        while (pos < len) {
+                DHCP6Option *option = (DHCP6Option *)&solicit->options[pos];
+                uint16_t optcode = be16toh(option->code);
+                uint16_t optlen = be16toh(option->len);
+                uint8_t *optval = option->data;
+
+                switch(optcode) {
+                case SD_DHCP6_OPTION_CLIENTID:
+                        assert_se(!found_clientid);
+                        found_clientid = true;
+
+                        assert_se(optlen == sizeof(test_duid));
+                        memcpy(&test_duid, optval, sizeof(test_duid));
+
+                        break;
+
+                case SD_DHCP6_OPTION_IA_NA:
+                        assert_se(!found_iana);
+                        found_iana = true;
+
+                        assert_se(optlen == 12);
+
+                        memcpy(&test_iaid, optval, sizeof(test_iaid));
+
+                        break;
+
+                case SD_DHCP6_OPTION_ELAPSED_TIME:
+                        assert_se(!found_elapsed_time);
+                        found_elapsed_time = true;
+
+                        assert_se(optlen == 2);
+
+                        break;
+
+                case SD_DHCP6_OPTION_FQDN:
+                        assert_se(!found_fqdn);
+                        found_fqdn = true;
+
+                        assert_se(optlen == 17);
+
+                        assert_se(optval[0] == 0x01);
+                        assert_se(!memcmp(optval + 1, fqdn_wire, sizeof(fqdn_wire)));
+
+                        break;
+                }
+
+                pos += sizeof(*option) + optlen;
+        }
+
+        assert_se(pos == len);
+        assert_se(found_clientid && found_iana && found_elapsed_time);
+
+        return 0;
+}
+
+static void test_client_information_cb(sd_dhcp6_client *client, int event,
+                                       void *userdata) {
+        sd_event *e = userdata;
+        sd_dhcp6_lease *lease;
+        const struct in6_addr *addrs;
+        struct in6_addr address = { { { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } };
+        char **domains;
+        const char *fqdn;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(e);
+        assert_se(event == SD_DHCP6_CLIENT_EVENT_INFORMATION_REQUEST);
+
+        assert_se(sd_dhcp6_client_get_lease(client, &lease) >= 0);
+
+        assert_se(sd_dhcp6_lease_get_domains(lease, &domains) == 1);
+        assert_se(!strcmp("lab.intra", domains[0]));
+        assert_se(domains[1] == NULL);
+
+        assert_se(sd_dhcp6_lease_get_fqdn(lease, &fqdn) >= 0);
+        assert_se(streq(fqdn, "client.intra"));
+
+        assert_se(sd_dhcp6_lease_get_dns(lease, &addrs) == 1);
+        assert_se(!memcmp(addrs, &msg_advertise[124], 16));
+
+        assert_se(sd_dhcp6_lease_get_ntp_addrs(lease, &addrs) == 1);
+        assert_se(!memcmp(addrs, &msg_advertise[159], 16));
+
+        assert_se(sd_dhcp6_client_set_information_request(client, false) == -EBUSY);
+        assert_se(sd_dhcp6_client_set_callback(client, NULL, e) >= 0);
+        assert_se(sd_dhcp6_client_stop(client) >= 0);
+        assert_se(sd_dhcp6_client_set_information_request(client, false) >= 0);
+
+        assert_se(sd_dhcp6_client_set_callback(client,
+                                               test_client_solicit_cb, e) >= 0);
+
+        assert_se(sd_dhcp6_client_set_local_address(client, &address) >= 0);
+
+        assert_se(sd_dhcp6_client_start(client) >= 0);
+
+}
+
+static int test_client_verify_information_request(DHCP6Message *information_request,
+                                                  size_t len) {
+
+        _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease = NULL;
+        size_t pos = 0;
+        bool found_clientid = false, found_elapsed_time = false;
+        struct in6_addr addr;
+        uint32_t lt_pref, lt_valid;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(information_request->type == DHCP6_INFORMATION_REQUEST);
+        assert_se(dhcp6_lease_new(&lease) >= 0);
+
+        len -= sizeof(DHCP6Message);
+
+        while (pos < len) {
+                DHCP6Option *option = (DHCP6Option *)&information_request->options[pos];
+                uint16_t optcode = be16toh(option->code);
+                uint16_t optlen = be16toh(option->len);
+                uint8_t *optval = option->data;
+
+                switch(optcode) {
+                case SD_DHCP6_OPTION_CLIENTID:
+                        assert_se(!found_clientid);
+                        found_clientid = true;
+
+                        assert_se(optlen == sizeof(test_duid));
+                        memcpy(&test_duid, optval, sizeof(test_duid));
+
+                        break;
+
+                case SD_DHCP6_OPTION_IA_NA:
+                        assert_not_reached("IA TA option must not be present");
+
+                        break;
+
+                case SD_DHCP6_OPTION_SERVERID:
+                        assert_not_reached("Server ID option must not be present");
+
+                        break;
+
+                case SD_DHCP6_OPTION_ELAPSED_TIME:
+                        assert_se(!found_elapsed_time);
+                        found_elapsed_time = true;
+
+                        assert_se(optlen == 2);
+
+                        break;
+                }
+
+                pos += sizeof(*option) + optlen;
+        }
+
+        assert_se(pos == len);
+        assert_se(found_clientid && found_elapsed_time);
+
+        sd_dhcp6_lease_reset_address_iter(lease);
+
+        assert_se(sd_dhcp6_lease_get_address(lease, &addr, &lt_pref,
+                                             &lt_valid) == -ENOMSG);
+
+        return 0;
+}
+
+int dhcp6_network_send_udp_socket(int s, struct in6_addr *server_address,
+                                  const void *packet, size_t len) {
+        struct in6_addr mcast =
+                IN6ADDR_ALL_DHCP6_RELAY_AGENTS_AND_SERVERS_INIT;
+        DHCP6Message *message;
+
+        assert_se(s == test_dhcp_fd[0]);
+        assert_se(server_address);
+        assert_se(packet);
+        assert_se(len > sizeof(DHCP6Message) + 4);
+        assert_se(IN6_ARE_ADDR_EQUAL(server_address, &mcast));
+
+        message = (DHCP6Message *)packet;
+
+        assert_se(message->transaction_id & 0x00ffffff);
+
+        if (test_client_message_num == 0) {
+                test_client_verify_information_request(message, len);
+                test_client_send_reply(message);
+                test_client_message_num++;
+        } else if (test_client_message_num == 1) {
+                test_client_verify_solicit(message, len);
+                test_client_send_advertise(message);
+                test_client_message_num++;
+        } else if (test_client_message_num == 2) {
+                test_client_verify_request(message, len);
+                test_client_send_reply(message);
+                test_client_message_num++;
+        }
+
+        return len;
+}
+
+int dhcp6_network_bind_udp_socket(int ifindex, struct in6_addr *local_address) {
+        assert_se(ifindex == test_ifindex);
+
+        if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_dhcp_fd) < 0)
+                return -errno;
+
+        return test_dhcp_fd[0];
+}
+
+static int test_client_solicit(sd_event *e) {
+        sd_dhcp6_client *client;
+        struct in6_addr address = { { { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } };
+        int val;
+
+        log_debug("/* %s */", __func__);
+
+        assert_se(sd_dhcp6_client_new(&client) >= 0);
+        assert_se(client);
+
+        assert_se(sd_dhcp6_client_attach_event(client, e, 0) >= 0);
+
+        assert_se(sd_dhcp6_client_set_ifindex(client, test_ifindex) == 0);
+        assert_se(sd_dhcp6_client_set_mac(client, (const uint8_t *) &mac_addr,
+                                          sizeof (mac_addr),
+                                          ARPHRD_ETHER) >= 0);
+        assert_se(sd_dhcp6_client_set_fqdn(client, "host.lab.intra") == 1);
+
+        assert_se(sd_dhcp6_client_get_information_request(client, &val) >= 0);
+        assert_se(val == 0);
+        assert_se(sd_dhcp6_client_set_information_request(client, 42) >= 0);
+        assert_se(sd_dhcp6_client_get_information_request(client, &val) >= 0);
+        assert_se(val);
+
+        assert_se(sd_dhcp6_client_set_callback(client,
+                                               test_client_information_cb, e) >= 0);
+
+        assert_se(sd_event_add_time_relative(e, &hangcheck, clock_boottime_or_monotonic(),
+                                             2 * USEC_PER_SEC, 0,
+                                             test_hangcheck, NULL) >= 0);
+
+        assert_se(sd_dhcp6_client_set_local_address(client, &address) >= 0);
+
+        assert_se(sd_dhcp6_client_start(client) >= 0);
+
+        sd_event_loop(e);
+
+        hangcheck = sd_event_source_unref(hangcheck);
+
+        assert_se(!sd_dhcp6_client_unref(client));
+
+        test_dhcp_fd[1] = safe_close(test_dhcp_fd[1]);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *e;
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        test_setup_logging(LOG_DEBUG);
+
+        test_client_basic(e);
+        test_option(e);
+        test_option_status(e);
+        test_advertise_option(e);
+        test_client_solicit(e);
+        test_parse_domain(e);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-ipv4ll-manual.c b/src/libsystemd-network/test-ipv4ll-manual.c
new file mode 100644
index 0000000..a253acb
--- /dev/null
+++ b/src/libsystemd-network/test-ipv4ll-manual.c
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <net/if.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <linux/veth.h>
+
+#include "sd-event.h"
+#include "sd-ipv4ll.h"
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "in-addr-util.h"
+#include "netlink-util.h"
+#include "parse-util.h"
+#include "string-util.h"
+#include "tests.h"
+#include "util.h"
+
+static void ll_handler(sd_ipv4ll *ll, int event, void *userdata) {
+        _cleanup_free_ char *address = NULL;
+        struct in_addr addr = {};
+
+        assert_se(ll);
+
+        if (sd_ipv4ll_get_address(ll, &addr) >= 0)
+                assert_se(in_addr_to_string(AF_INET, (const union in_addr_union*) &addr, &address) >= 0);
+
+        switch (event) {
+        case SD_IPV4LL_EVENT_BIND:
+                log_info("bound %s", strna(address));
+                break;
+        case SD_IPV4LL_EVENT_CONFLICT:
+                log_info("conflict on %s", strna(address));
+                break;
+        case SD_IPV4LL_EVENT_STOP:
+                log_error("the client was stopped with address %s", strna(address));
+                break;
+        default:
+                assert_not_reached("invalid LL event");
+        }
+}
+
+static int client_run(int ifindex, const char *seed_str, const struct ether_addr *ha, sd_event *e) {
+        sd_ipv4ll *ll;
+
+        assert_se(sd_ipv4ll_new(&ll) >= 0);
+        assert_se(sd_ipv4ll_attach_event(ll, e, 0) >= 0);
+
+        assert_se(sd_ipv4ll_set_ifindex(ll, ifindex) >= 0);
+        assert_se(sd_ipv4ll_set_mac(ll, ha) >= 0);
+        assert_se(sd_ipv4ll_set_callback(ll, ll_handler, NULL) >= 0);
+
+        if (seed_str) {
+                unsigned seed;
+
+                assert_se(safe_atou(seed_str, &seed) >= 0);
+
+                assert_se(sd_ipv4ll_set_address_seed(ll, seed) >= 0);
+        }
+
+        log_info("starting IPv4LL client");
+
+        assert_se(sd_ipv4ll_start(ll) >= 0);
+
+        assert_se(sd_event_loop(e) >= 0);
+
+        assert_se(!sd_ipv4ll_unref(ll));
+
+        return EXIT_SUCCESS;
+}
+
+static int test_ll(const char *ifname, const char *seed) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *reply = NULL;
+        struct ether_addr ha;
+        int ifindex;
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+        assert_se(sd_netlink_attach_event(rtnl, e, 0) >= 0);
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, 0) >= 0);
+        assert_se(sd_netlink_message_append_string(m, IFLA_IFNAME, ifname) >= 0);
+        assert_se(sd_netlink_call(rtnl, m, 0, &reply) >= 0);
+
+        assert_se(sd_rtnl_message_link_get_ifindex(reply, &ifindex) >= 0);
+        assert_se(sd_netlink_message_read_ether_addr(reply, IFLA_ADDRESS, &ha) >= 0);
+
+        client_run(ifindex, seed, &ha, e);
+
+        return EXIT_SUCCESS;
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_DEBUG);
+
+        if (argc == 2)
+                return test_ll(argv[1], NULL);
+        else if (argc == 3)
+                return test_ll(argv[1], argv[2]);
+        else {
+                log_error("This program takes one or two arguments.\n"
+                          "\t %s <ifname> [<seed>]", program_invocation_short_name);
+                return EXIT_FAILURE;
+        }
+}
diff --git a/src/libsystemd-network/test-ipv4ll.c b/src/libsystemd-network/test-ipv4ll.c
new file mode 100644
index 0000000..b213f41
--- /dev/null
+++ b/src/libsystemd-network/test-ipv4ll.c
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Axis Communications AB. All rights reserved.
+***/
+
+#include <errno.h>
+#include <netinet/if_ether.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "sd-ipv4ll.h"
+
+#include "arp-util.h"
+#include "fd-util.h"
+#include "socket-util.h"
+#include "tests.h"
+#include "util.h"
+
+static bool verbose = false;
+static bool extended = false;
+static int test_fd[2];
+
+static int basic_request_handler_bind = 0;
+static int basic_request_handler_stop = 0;
+static void* basic_request_handler_userdata = (void*) 0xCABCAB;
+
+static void basic_request_handler(sd_ipv4ll *ll, int event, void *userdata) {
+        assert_se(userdata == basic_request_handler_userdata);
+
+        switch(event) {
+                case SD_IPV4LL_EVENT_STOP:
+                        basic_request_handler_stop = 1;
+                        break;
+                case SD_IPV4LL_EVENT_BIND:
+                        basic_request_handler_bind = 1;
+                        break;
+                default:
+                        assert_se(0);
+                        break;
+        }
+}
+
+static int arp_network_send_raw_socket(int fd, int ifindex,
+                                       const struct ether_arp *arp) {
+        assert_se(arp);
+        assert_se(ifindex > 0);
+        assert_se(fd >= 0);
+
+        if (send(fd, arp, sizeof(struct ether_arp), 0) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int arp_send_probe(int fd, int ifindex,
+                    be32_t pa, const struct ether_addr *ha) {
+        struct ether_arp ea = {};
+
+        assert_se(fd >= 0);
+        assert_se(ifindex > 0);
+        assert_se(pa != 0);
+        assert_se(ha);
+
+        return arp_network_send_raw_socket(fd, ifindex, &ea);
+}
+
+int arp_send_announcement(int fd, int ifindex,
+                          be32_t pa, const struct ether_addr *ha) {
+        struct ether_arp ea = {};
+
+        assert_se(fd >= 0);
+        assert_se(ifindex > 0);
+        assert_se(pa != 0);
+        assert_se(ha);
+
+        return arp_network_send_raw_socket(fd, ifindex, &ea);
+}
+
+int arp_network_bind_raw_socket(int ifindex, be32_t address, const struct ether_addr *eth_mac) {
+        if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_fd) < 0)
+                return -errno;
+
+        return test_fd[0];
+}
+
+static void test_public_api_setters(sd_event *e) {
+        struct in_addr address = {};
+        uint64_t seed = 0;
+        sd_ipv4ll *ll;
+        struct ether_addr mac_addr = {
+                .ether_addr_octet = {'A', 'B', 'C', '1', '2', '3'}};
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        assert_se(sd_ipv4ll_new(&ll) == 0);
+        assert_se(ll);
+
+        assert_se(sd_ipv4ll_attach_event(NULL, NULL, 0) == -EINVAL);
+        assert_se(sd_ipv4ll_attach_event(ll, e, 0) == 0);
+        assert_se(sd_ipv4ll_attach_event(ll, e, 0) == -EBUSY);
+
+        assert_se(sd_ipv4ll_set_callback(NULL, NULL, NULL) == -EINVAL);
+        assert_se(sd_ipv4ll_set_callback(ll, NULL, NULL) == 0);
+
+        assert_se(sd_ipv4ll_set_address(ll, &address) == -EINVAL);
+        address.s_addr |= htobe32(169U << 24 | 254U << 16);
+        assert_se(sd_ipv4ll_set_address(ll, &address) == -EINVAL);
+        address.s_addr |= htobe32(0x00FF);
+        assert_se(sd_ipv4ll_set_address(ll, &address) == -EINVAL);
+        address.s_addr |= htobe32(0xF000);
+        assert_se(sd_ipv4ll_set_address(ll, &address) == 0);
+        address.s_addr |= htobe32(0x0F00);
+        assert_se(sd_ipv4ll_set_address(ll, &address) == -EINVAL);
+
+        assert_se(sd_ipv4ll_set_address_seed(NULL, seed) == -EINVAL);
+        assert_se(sd_ipv4ll_set_address_seed(ll, seed) == 0);
+
+        assert_se(sd_ipv4ll_set_mac(NULL, NULL) == -EINVAL);
+        assert_se(sd_ipv4ll_set_mac(ll, NULL) == -EINVAL);
+        assert_se(sd_ipv4ll_set_mac(ll, &mac_addr) == 0);
+
+        assert_se(sd_ipv4ll_set_ifindex(NULL, -1) == -EINVAL);
+        assert_se(sd_ipv4ll_set_ifindex(ll, -1) == -EINVAL);
+        assert_se(sd_ipv4ll_set_ifindex(ll, -99) == -EINVAL);
+        assert_se(sd_ipv4ll_set_ifindex(ll, 1) == 0);
+        assert_se(sd_ipv4ll_set_ifindex(ll, 99) == 0);
+
+        assert_se(sd_ipv4ll_ref(ll) == ll);
+        assert_se(sd_ipv4ll_unref(ll) == NULL);
+
+        /* Cleanup */
+        assert_se(sd_ipv4ll_unref(ll) == NULL);
+}
+
+static void test_basic_request(sd_event *e) {
+
+        sd_ipv4ll *ll;
+        struct ether_arp arp;
+        struct ether_addr mac_addr = {
+                .ether_addr_octet = {'A', 'B', 'C', '1', '2', '3'}};
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        assert_se(sd_ipv4ll_new(&ll) == 0);
+        assert_se(sd_ipv4ll_start(ll) == -EINVAL);
+
+        assert_se(sd_ipv4ll_attach_event(ll, e, 0) == 0);
+        assert_se(sd_ipv4ll_start(ll) == -EINVAL);
+
+        assert_se(sd_ipv4ll_set_mac(ll, &mac_addr) == 0);
+        assert_se(sd_ipv4ll_start(ll) == -EINVAL);
+
+        assert_se(sd_ipv4ll_set_callback(ll, basic_request_handler,
+                                         basic_request_handler_userdata) == 0);
+        assert_se(sd_ipv4ll_start(ll) == -EINVAL);
+
+        assert_se(sd_ipv4ll_set_ifindex(ll, 1) == 0);
+        assert_se(sd_ipv4ll_start(ll) == 1);
+
+        sd_event_run(e, (uint64_t) -1);
+        assert_se(sd_ipv4ll_start(ll) == 0);
+
+        assert_se(sd_ipv4ll_is_running(ll));
+
+        /* PROBE */
+        sd_event_run(e, (uint64_t) -1);
+        assert_se(recv(test_fd[1], &arp, sizeof(struct ether_arp), 0) == sizeof(struct ether_arp));
+
+        if (extended) {
+                /* PROBE */
+                sd_event_run(e, (uint64_t) -1);
+                assert_se(recv(test_fd[1], &arp, sizeof(struct ether_arp), 0) == sizeof(struct ether_arp));
+
+                /* PROBE */
+                sd_event_run(e, (uint64_t) -1);
+                assert_se(recv(test_fd[1], &arp, sizeof(struct ether_arp), 0) == sizeof(struct ether_arp));
+
+                sd_event_run(e, (uint64_t) -1);
+                assert_se(basic_request_handler_bind == 1);
+        }
+
+        sd_ipv4ll_stop(ll);
+        assert_se(basic_request_handler_stop == 1);
+
+        /* Cleanup */
+        assert_se(sd_ipv4ll_unref(ll) == NULL);
+        safe_close(test_fd[1]);
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+
+        test_setup_logging(LOG_DEBUG);
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        test_public_api_setters(e);
+        test_basic_request(e);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-lldp.c b/src/libsystemd-network/test-lldp.c
new file mode 100644
index 0000000..c52d422
--- /dev/null
+++ b/src/libsystemd-network/test-lldp.c
@@ -0,0 +1,378 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <net/ethernet.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "sd-event.h"
+#include "sd-lldp.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "lldp-network.h"
+#include "macro.h"
+#include "string-util.h"
+#include "tests.h"
+
+#define TEST_LLDP_PORT "em1"
+#define TEST_LLDP_TYPE_SYSTEM_NAME "systemd-lldp"
+#define TEST_LLDP_TYPE_SYSTEM_DESC "systemd-lldp-desc"
+
+static int test_fd[2] = { -1, -1 };
+static int lldp_handler_calls;
+
+int lldp_network_bind_raw_socket(int ifindex) {
+        if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_fd) < 0)
+                return -errno;
+
+        return test_fd[0];
+}
+
+static void lldp_handler(sd_lldp *lldp, sd_lldp_event event, sd_lldp_neighbor *n, void *userdata) {
+        lldp_handler_calls++;
+}
+
+static int start_lldp(sd_lldp **lldp, sd_event *e, sd_lldp_callback_t cb, void *cb_data) {
+        int r;
+
+        r = sd_lldp_new(lldp);
+        if (r < 0)
+                return r;
+
+        r = sd_lldp_set_ifindex(*lldp, 42);
+        if (r < 0)
+                return r;
+
+        r = sd_lldp_set_callback(*lldp, cb, cb_data);
+        if (r < 0)
+                return r;
+
+        r = sd_lldp_attach_event(*lldp, e, 0);
+        if (r < 0)
+                return r;
+
+        r = sd_lldp_start(*lldp);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int stop_lldp(sd_lldp *lldp) {
+        int r;
+
+        r = sd_lldp_stop(lldp);
+        if (r < 0)
+                return r;
+
+        r = sd_lldp_detach_event(lldp);
+        if (r < 0)
+                return r;
+
+        sd_lldp_unref(lldp);
+        safe_close(test_fd[1]);
+
+        return 0;
+}
+
+static void test_receive_basic_packet(sd_event *e) {
+
+        static const uint8_t frame[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x07, 0x04, 0x00, 0x01, 0x02,     /* Chassis: MAC, 00:01:02:03:04:05 */
+                0x03, 0x04, 0x05,
+                0x04, 0x04, 0x05, 0x31, 0x2f, 0x33,     /* Port: interface name, "1/3" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                /* LLDP optional TLVs */
+                0x08, 0x04, 0x50, 0x6f, 0x72, 0x74,     /* Port Description: "Port" */
+                0x0a, 0x03, 0x53, 0x59, 0x53,           /* System Name: "SYS" */
+                0x0c, 0x04, 0x66, 0x6f, 0x6f, 0x00,     /* System Description: "foo" (NULL-terminated) */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+
+        sd_lldp *lldp;
+        sd_lldp_neighbor **neighbors;
+        uint8_t type;
+        const void *data;
+        uint16_t ttl;
+        size_t length;
+        const char *str;
+
+        lldp_handler_calls = 0;
+        assert_se(start_lldp(&lldp, e, lldp_handler, NULL) == 0);
+
+        assert_se(write(test_fd[1], frame, sizeof(frame)) == sizeof(frame));
+        sd_event_run(e, 0);
+        assert_se(lldp_handler_calls == 1);
+        assert_se(sd_lldp_get_neighbors(lldp, &neighbors) == 1);
+
+        assert_se(sd_lldp_neighbor_get_chassis_id(neighbors[0], &type, &data, &length) == 0);
+        assert_se(type == SD_LLDP_CHASSIS_SUBTYPE_MAC_ADDRESS);
+        assert_se(length == ETH_ALEN);
+        assert_se(!memcmp(data, "\x00\x01\x02\x03\x04\x05", ETH_ALEN));
+
+        assert_se(sd_lldp_neighbor_get_port_id(neighbors[0], &type, &data, &length) == 0);
+        assert_se(type == SD_LLDP_PORT_SUBTYPE_INTERFACE_NAME);
+        assert_se(length == 3);
+        assert_se(!memcmp(data, "1/3", 3));
+
+        assert_se(sd_lldp_neighbor_get_port_description(neighbors[0], &str) == 0);
+        assert_se(streq(str, "Port"));
+
+        assert_se(sd_lldp_neighbor_get_system_name(neighbors[0], &str) == 0);
+        assert_se(streq(str, "SYS"));
+
+        assert_se(sd_lldp_neighbor_get_system_description(neighbors[0], &str) == 0);
+        assert_se(streq(str, "foo"));
+
+        assert_se(sd_lldp_neighbor_get_ttl(neighbors[0], &ttl) == 0);
+        assert_se(ttl == 120);
+
+        sd_lldp_neighbor_unref(neighbors[0]);
+        free(neighbors);
+
+        assert_se(stop_lldp(lldp) == 0);
+}
+
+static void test_receive_incomplete_packet(sd_event *e) {
+        sd_lldp *lldp;
+        sd_lldp_neighbor **neighbors;
+        uint8_t frame[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x07, 0x04, 0x00, 0x01, 0x02,     /* Chassis: MAC, 00:01:02:03:04:05 */
+                0x03, 0x04, 0x05,
+                0x04, 0x04, 0x05, 0x31, 0x2f, 0x33,     /* Port: interface name, "1/3" */
+                                                        /* Missing TTL */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+
+        lldp_handler_calls = 0;
+        assert_se(start_lldp(&lldp, e, lldp_handler, NULL) == 0);
+
+        assert_se(write(test_fd[1], frame, sizeof(frame)) == sizeof(frame));
+        sd_event_run(e, 0);
+        assert_se(lldp_handler_calls == 0);
+        assert_se(sd_lldp_get_neighbors(lldp, &neighbors) == 0);
+
+        assert_se(stop_lldp(lldp) == 0);
+}
+
+static void test_receive_oui_packet(sd_event *e) {
+        sd_lldp *lldp;
+        sd_lldp_neighbor **neighbors;
+        uint8_t frame[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x07, 0x04, 0x00, 0x01, 0x02,     /* Chassis: MAC, 00:01:02:03:04:05 */
+                0x03, 0x04, 0x05,
+                0x04, 0x04, 0x05, 0x31, 0x2f, 0x33,     /* Port TLV: interface name, "1/3" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                /* LLDP optional TLVs */
+                0xfe, 0x06, 0x00, 0x80, 0xc2, 0x01,     /* Port VLAN ID: 0x1234 */
+                0x12, 0x34,
+                0xfe, 0x07, 0x00, 0x80, 0xc2, 0x02,     /* Port and protocol: flag 1, PPVID 0x7788 */
+                0x01, 0x77, 0x88,
+                0xfe, 0x0d, 0x00, 0x80, 0xc2, 0x03,     /* VLAN Name: ID 0x1234, name "Vlan51" */
+                0x12, 0x34, 0x06, 0x56, 0x6c, 0x61,
+                0x6e, 0x35, 0x31,
+                0xfe, 0x06, 0x00, 0x80, 0xc2, 0x06,     /* Management VID: 0x0102 */
+                0x01, 0x02,
+                0xfe, 0x09, 0x00, 0x80, 0xc2, 0x07,     /* Link aggregation: status 1, ID 0x00140012 */
+                0x01, 0x00, 0x14, 0x00, 0x12,
+                0xfe, 0x07, 0x00, 0x12, 0x0f, 0x02,     /* 802.3 Power via MDI: PSE, MDI enabled */
+                0x07, 0x01, 0x00,
+                0x00, 0x00                              /* End of LLDPDU */
+        };
+
+        lldp_handler_calls = 0;
+        assert_se(start_lldp(&lldp, e, lldp_handler, NULL) == 0);
+
+        assert_se(write(test_fd[1], frame, sizeof(frame)) == sizeof(frame));
+        sd_event_run(e, 0);
+        assert_se(lldp_handler_calls == 1);
+        assert_se(sd_lldp_get_neighbors(lldp, &neighbors) == 1);
+
+        assert_se(sd_lldp_neighbor_tlv_rewind(neighbors[0]) >= 0);
+        assert_se(sd_lldp_neighbor_tlv_is_type(neighbors[0], SD_LLDP_TYPE_CHASSIS_ID) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_type(neighbors[0], SD_LLDP_TYPE_PORT_ID) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_type(neighbors[0], SD_LLDP_TYPE_TTL) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_oui(neighbors[0], SD_LLDP_OUI_802_1, SD_LLDP_OUI_802_1_SUBTYPE_PORT_VLAN_ID) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_oui(neighbors[0], SD_LLDP_OUI_802_1, SD_LLDP_OUI_802_1_SUBTYPE_PORT_PROTOCOL_VLAN_ID) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_oui(neighbors[0], SD_LLDP_OUI_802_1, SD_LLDP_OUI_802_1_SUBTYPE_VLAN_NAME) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_oui(neighbors[0], SD_LLDP_OUI_802_1, SD_LLDP_OUI_802_1_SUBTYPE_MANAGEMENT_VID) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_oui(neighbors[0], SD_LLDP_OUI_802_1, SD_LLDP_OUI_802_1_SUBTYPE_LINK_AGGREGATION) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_oui(neighbors[0], SD_LLDP_OUI_802_3, SD_LLDP_OUI_802_3_SUBTYPE_POWER_VIA_MDI) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) > 0);
+        assert_se(sd_lldp_neighbor_tlv_is_type(neighbors[0], SD_LLDP_TYPE_END) > 0);
+        assert_se(sd_lldp_neighbor_tlv_next(neighbors[0]) == 0);
+
+        sd_lldp_neighbor_unref(neighbors[0]);
+        free(neighbors);
+
+        assert_se(stop_lldp(lldp) == 0);
+}
+
+static void test_multiple_neighbors_sorted(sd_event *e) {
+
+        static const uint8_t frame1[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x04, 0x01, '1', '/', '2',        /* Chassis component: "1/2" */
+                0x04, 0x04, 0x02, '2', '/', '3',        /* Port component: "2/3" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+        static const uint8_t frame2[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x04, 0x01, '2', '/', '1',        /* Chassis component: "2/1" */
+                0x04, 0x04, 0x02, '1', '/', '3',        /* Port component: "1/3" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+        static const uint8_t frame3[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x05, 0x01, '2', '/', '1', '0',   /* Chassis component: "2/10" */
+                0x04, 0x04, 0x02, '1', '/', '0',        /* Port component: "1/0" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+        static const uint8_t frame4[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x05, 0x01, '2', '/', '1', '9',   /* Chassis component: "2/19" */
+                0x04, 0x04, 0x02, '1', '/', '0',        /* Port component: "1/0" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+        static const uint8_t frame5[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x04, 0x01, '1', '/', '2',        /* Chassis component: "1/2" */
+                0x04, 0x05, 0x02, '2', '/', '1', '0',   /* Port component: "2/10" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+        static const uint8_t frame6[] = {
+                /* Ethernet header */
+                0x01, 0x80, 0xc2, 0x00, 0x00, 0x03,     /* Destination MAC */
+                0x01, 0x02, 0x03, 0x04, 0x05, 0x06,     /* Source MAC */
+                0x88, 0xcc,                             /* Ethertype */
+                /* LLDP mandatory TLVs */
+                0x02, 0x04, 0x01, '1', '/', '2',        /* Chassis component: "1/2" */
+                0x04, 0x05, 0x02, '2', '/', '3', '9',   /* Port component: "2/10" */
+                0x06, 0x02, 0x00, 0x78,                 /* TTL: 120 seconds */
+                0x00, 0x00                              /* End Of LLDPDU */
+        };
+        static const char* expected[] = {
+                /* ordered pairs of Chassis+Port */
+                "1/2", "2/10",
+                "1/2", "2/3",
+                "1/2", "2/39",
+                "2/1", "1/3",
+                "2/10", "1/0",
+                "2/19", "1/0",
+        };
+
+        sd_lldp *lldp;
+        sd_lldp_neighbor **neighbors;
+        int i;
+        uint8_t type;
+        const void *data;
+        size_t length, expected_length;
+        uint16_t ttl;
+
+        lldp_handler_calls = 0;
+        assert_se(start_lldp(&lldp, e, lldp_handler, NULL) == 0);
+
+        assert_se(write(test_fd[1], frame1, sizeof(frame1)) == sizeof(frame1));
+        sd_event_run(e, 0);
+        assert_se(write(test_fd[1], frame2, sizeof(frame2)) == sizeof(frame2));
+        sd_event_run(e, 0);
+        assert_se(write(test_fd[1], frame3, sizeof(frame3)) == sizeof(frame3));
+        sd_event_run(e, 0);
+        assert_se(write(test_fd[1], frame4, sizeof(frame4)) == sizeof(frame4));
+        sd_event_run(e, 0);
+        assert_se(write(test_fd[1], frame5, sizeof(frame5)) == sizeof(frame5));
+        sd_event_run(e, 0);
+        assert_se(write(test_fd[1], frame6, sizeof(frame6)) == sizeof(frame6));
+        sd_event_run(e, 0);
+        assert_se(lldp_handler_calls == 6);
+
+        assert_se(sd_lldp_get_neighbors(lldp, &neighbors) == 6);
+
+        for (i = 0; i < 6; i++) {
+                assert_se(sd_lldp_neighbor_get_chassis_id(neighbors[i], &type, &data, &length) == 0);
+                assert_se(type == SD_LLDP_CHASSIS_SUBTYPE_CHASSIS_COMPONENT);
+                expected_length = strlen(expected[2 * i]);
+                assert_se(length == expected_length);
+                assert_se(memcmp(data, expected[2 * i], expected_length) == 0);
+
+                assert_se(sd_lldp_neighbor_get_port_id(neighbors[i], &type, &data, &length) == 0);
+                assert_se(type == SD_LLDP_PORT_SUBTYPE_PORT_COMPONENT);
+                expected_length = strlen(expected[2 * i + 1]);
+                assert_se(length == expected_length);
+                assert_se(memcmp(data, expected[2 * i + 1], expected_length) == 0);
+
+                assert_se(sd_lldp_neighbor_get_ttl(neighbors[i], &ttl) == 0);
+                assert_se(ttl == 120);
+        }
+
+        for (i = 0; i < 6; i++)
+                sd_lldp_neighbor_unref(neighbors[i]);
+        free(neighbors);
+
+        assert_se(stop_lldp(lldp) == 0);
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+
+        test_setup_logging(LOG_DEBUG);
+
+        /* LLDP reception tests */
+        assert_se(sd_event_new(&e) == 0);
+        test_receive_basic_packet(e);
+        test_receive_incomplete_packet(e);
+        test_receive_oui_packet(e);
+        test_multiple_neighbors_sorted(e);
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-ndisc-ra.c b/src/libsystemd-network/test-ndisc-ra.c
new file mode 100644
index 0000000..927e21b
--- /dev/null
+++ b/src/libsystemd-network/test-ndisc-ra.c
@@ -0,0 +1,370 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2017 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/icmp6.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+
+#include "sd-radv.h"
+
+#include "alloc-util.h"
+#include "hexdecoct.h"
+#include "icmp6-util.h"
+#include "socket-util.h"
+#include "strv.h"
+#include "tests.h"
+
+static struct ether_addr mac_addr = {
+        .ether_addr_octet = { 0x78, 0x2b, 0xcb, 0xb3, 0x6d, 0x53 }
+};
+
+static uint8_t advertisement[] = {
+        /* ICMPv6 Router Advertisement, no checksum */
+        0x86, 0x00, 0x00, 0x00,  0x40, 0xc0, 0x00, 0xb4,
+        0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+        /* Source Link Layer Address Option */
+        0x01, 0x01, 0x78, 0x2b,  0xcb, 0xb3, 0x6d, 0x53,
+        /* Prefix Information Option */
+        0x03, 0x04, 0x40, 0xc0,  0x00, 0x00, 0x01, 0xf4,
+        0x00, 0x00, 0x01, 0xb8,  0x00, 0x00, 0x00, 0x00,
+        0x20, 0x01, 0x0d, 0xb8,  0xde, 0xad, 0xbe, 0xef,
+        0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+        /* Prefix Information Option */
+        0x03, 0x04, 0x40, 0xc0,  0x00, 0x27, 0x8d, 0x00,
+        0x00, 0x09, 0x3a, 0x80,  0x00, 0x00, 0x00, 0x00,
+        0x20, 0x01, 0x0d, 0xb8,  0x0b, 0x16, 0xd0, 0x0d,
+        0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+        /* Prefix Information Option */
+        0x03, 0x04, 0x30, 0xc0,  0x00, 0x27, 0x8d, 0x00,
+        0x00, 0x09, 0x3a, 0x80,  0x00, 0x00, 0x00, 0x00,
+        0x20, 0x01, 0x0d, 0xb8,  0xc0, 0x01, 0x0d, 0xad,
+        0x00, 0x00, 0x00, 0x00,  0x00, 0x00, 0x00, 0x00,
+        /* Recursive DNS Server Option */
+        0x19, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c,
+        0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe, 0xef,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+        /* DNS Search List Option */
+        0x1f, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c,
+        0x03, 0x6c, 0x61, 0x62, 0x05, 0x69, 0x6e, 0x74,
+        0x72, 0x61, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+};
+
+static sd_event_source *test_hangcheck;
+static bool test_stopped;
+static int test_fd[2];
+static sd_event_source *recv_router_advertisement;
+static struct {
+        struct in6_addr address;
+        unsigned char prefixlen;
+        uint32_t valid;
+        uint32_t preferred;
+        bool successful;
+} prefix[] = {
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe, 0xef,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 64,
+          500, 440, true },
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0x0b, 0x16, 0xd0, 0x0d,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 64,
+          /* indicate default valid and preferred lifetimes for the test code */
+          0, 0, true },
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0x0b, 0x16, 0xd0, 0x0d,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 58,
+          0, 0,
+          /* indicate that this prefix already exists */
+          false },
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0x0b, 0x16, 0xd0, 0x0d,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 120,
+          0, 0,
+          /* indicate that this prefix already exists */
+          false },
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0x0b, 0x16, 0xd0, 0x0d,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 12,
+          0, 0,
+          /* indicate that this prefix already exists */
+          false },
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0xc0, 0x01, 0x0d, 0xad,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 48,
+          0, 0, true },
+        { { { { 0x20, 0x01, 0x0d, 0xb8, 0xc0, 0x01, 0x0d, 0xad,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } } }, 60,
+          0, 0,
+          /* indicate that this prefix already exists */
+          false },
+};
+
+static const struct in6_addr test_rdnss = { { { 0x20, 0x01, 0x0d, 0xb8,
+                                                0xde, 0xad, 0xbe, 0xef,
+                                                0x00, 0x00, 0x00, 0x00,
+                                                0x00, 0x00, 0x00, 0x01 } } };
+static const char *test_dnssl[] = { "lab.intra",
+                                    NULL };
+
+static int test_rs_hangcheck(sd_event_source *s, uint64_t usec,
+                             void *userdata) {
+        assert_se(false);
+
+        return 0;
+}
+
+static void test_radv_prefix(void) {
+        sd_radv_prefix *p;
+
+        printf("* %s\n", __FUNCTION__);
+
+        assert_se(sd_radv_prefix_new(&p) >= 0);
+
+        assert_se(sd_radv_prefix_set_onlink(NULL, true) < 0);
+        assert_se(sd_radv_prefix_set_onlink(p, true) >= 0);
+        assert_se(sd_radv_prefix_set_onlink(p, false) >= 0);
+
+        assert_se(sd_radv_prefix_set_address_autoconfiguration(NULL, true) < 0);
+        assert_se(sd_radv_prefix_set_address_autoconfiguration(p, true) >= 0);
+        assert_se(sd_radv_prefix_set_address_autoconfiguration(p, false) >= 0);
+
+        assert_se(sd_radv_prefix_set_valid_lifetime(NULL, true) < 0);
+        assert_se(sd_radv_prefix_set_valid_lifetime(p, ~0) >= 0);
+        assert_se(sd_radv_prefix_set_valid_lifetime(p, 42) >= 0);
+        assert_se(sd_radv_prefix_set_valid_lifetime(p, 0) >= 0);
+
+        assert_se(sd_radv_prefix_set_preferred_lifetime(NULL, true) < 0);
+        assert_se(sd_radv_prefix_set_preferred_lifetime(p, ~0) >= 0);
+        assert_se(sd_radv_prefix_set_preferred_lifetime(p, 42) >= 0);
+        assert_se(sd_radv_prefix_set_preferred_lifetime(p, 0) >= 0);
+
+        assert_se(sd_radv_prefix_set_prefix(NULL, NULL, 0) < 0);
+        assert_se(sd_radv_prefix_set_prefix(p, NULL, 0) < 0);
+
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 64) >= 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 0) < 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 1) < 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 2) < 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 3) >= 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 125) >= 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 128) >= 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 129) < 0);
+        assert_se(sd_radv_prefix_set_prefix(p, &prefix[0].address, 255) < 0);
+
+        p = sd_radv_prefix_unref(p);
+        assert_se(!p);
+}
+
+static void test_radv(void) {
+        sd_radv *ra;
+
+        printf("* %s\n", __FUNCTION__);
+
+        assert_se(sd_radv_new(&ra) >= 0);
+        assert_se(ra);
+
+        assert_se(sd_radv_set_ifindex(NULL, 0) < 0);
+        assert_se(sd_radv_set_ifindex(ra, 0) < 0);
+        assert_se(sd_radv_set_ifindex(ra, -1) < 0);
+        assert_se(sd_radv_set_ifindex(ra, -2) < 0);
+        assert_se(sd_radv_set_ifindex(ra, 42) >= 0);
+
+        assert_se(sd_radv_set_mac(NULL, NULL) < 0);
+        assert_se(sd_radv_set_mac(ra, NULL) >= 0);
+        assert_se(sd_radv_set_mac(ra, &mac_addr) >= 0);
+
+        assert_se(sd_radv_set_mtu(NULL, 0) < 0);
+        assert_se(sd_radv_set_mtu(ra, 0) < 0);
+        assert_se(sd_radv_set_mtu(ra, 1279) < 0);
+        assert_se(sd_radv_set_mtu(ra, 1280) >= 0);
+        assert_se(sd_radv_set_mtu(ra, ~0) >= 0);
+
+        assert_se(sd_radv_set_hop_limit(NULL, 0) < 0);
+        assert_se(sd_radv_set_hop_limit(ra, 0) >= 0);
+        assert_se(sd_radv_set_hop_limit(ra, ~0) >= 0);
+
+        assert_se(sd_radv_set_router_lifetime(NULL, 0) < 0);
+        assert_se(sd_radv_set_router_lifetime(ra, 0) >= 0);
+        assert_se(sd_radv_set_router_lifetime(ra, ~0) >= 0);
+
+        assert_se(sd_radv_set_preference(NULL, 0) < 0);
+        assert_se(sd_radv_set_preference(ra, SD_NDISC_PREFERENCE_LOW) >= 0);
+        assert_se(sd_radv_set_preference(ra, SD_NDISC_PREFERENCE_MEDIUM) >= 0);
+        assert_se(sd_radv_set_preference(ra, SD_NDISC_PREFERENCE_HIGH) >= 0);
+        assert_se(sd_radv_set_preference(ra, ~0) < 0);
+
+        assert_se(sd_radv_set_preference(ra, SD_NDISC_PREFERENCE_HIGH) >= 0);
+        assert_se(sd_radv_set_router_lifetime(ra, 42000) >= 0);
+        assert_se(sd_radv_set_router_lifetime(ra, 0) < 0);
+        assert_se(sd_radv_set_preference(ra, SD_NDISC_PREFERENCE_MEDIUM) >= 0);
+        assert_se(sd_radv_set_router_lifetime(ra, 0) >= 0);
+
+        assert_se(sd_radv_set_managed_information(NULL, true) < 0);
+        assert_se(sd_radv_set_managed_information(ra, true) >= 0);
+        assert_se(sd_radv_set_managed_information(ra, false) >= 0);
+
+        assert_se(sd_radv_set_other_information(NULL, true) < 0);
+        assert_se(sd_radv_set_other_information(ra, true) >= 0);
+        assert_se(sd_radv_set_other_information(ra, false) >= 0);
+
+        assert_se(sd_radv_set_rdnss(NULL, 0, NULL, 0) < 0);
+        assert_se(sd_radv_set_rdnss(ra, 0, NULL, 0) >= 0);
+        assert_se(sd_radv_set_rdnss(ra, 0, NULL, 128) < 0);
+        assert_se(sd_radv_set_rdnss(ra, 600, &test_rdnss, 0) >= 0);
+        assert_se(sd_radv_set_rdnss(ra, 600, &test_rdnss, 1) >= 0);
+        assert_se(sd_radv_set_rdnss(ra, 0, &test_rdnss, 1) >= 0);
+        assert_se(sd_radv_set_rdnss(ra, 0, NULL, 0) >= 0);
+
+        assert_se(sd_radv_set_dnssl(ra, 0, NULL) >= 0);
+        assert_se(sd_radv_set_dnssl(ra, 600, NULL) >= 0);
+        assert_se(sd_radv_set_dnssl(ra, 0, (char **)test_dnssl) >= 0);
+        assert_se(sd_radv_set_dnssl(ra, 600, (char **)test_dnssl) >= 0);
+
+        ra = sd_radv_unref(ra);
+        assert_se(!ra);
+}
+
+int icmp6_bind_router_solicitation(int ifindex) {
+        return -ENOSYS;
+}
+
+int icmp6_bind_router_advertisement(int ifindex) {
+        assert_se(ifindex == 42);
+
+        return test_fd[1];
+}
+
+int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) {
+
+        return 0;
+}
+
+int icmp6_receive(int fd, void *iov_base, size_t iov_len,
+                  struct in6_addr *dst, triple_timestamp *timestamp) {
+        assert_se(read (fd, iov_base, iov_len) == (ssize_t)iov_len);
+
+        if (timestamp)
+                triple_timestamp_get(timestamp);
+
+        return 0;
+}
+
+static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_radv *ra = userdata;
+        unsigned char buf[168];
+        size_t i;
+
+        assert_se(read(test_fd[0], &buf, sizeof(buf)) == sizeof(buf));
+
+        /* router lifetime must be zero when test is stopped */
+        if (test_stopped) {
+                advertisement[6] = 0x00;
+                advertisement[7] = 0x00;
+        }
+
+        printf ("Received Router Advertisement with lifetime %u\n",
+                (advertisement[6] << 8) + advertisement[7]);
+
+        /* test only up to buf size, rest is not yet implemented */
+        for (i = 0; i < sizeof(buf); i++) {
+                if (!(i % 8))
+                        printf("%3zd: ", i);
+
+                printf("0x%02x", buf[i]);
+
+                assert_se(buf[i] == advertisement[i]);
+
+                if ((i + 1) % 8)
+                        printf(", ");
+                else
+                        printf("\n");
+        }
+
+        if (test_stopped) {
+                sd_event *e;
+
+                e = sd_radv_get_event(ra);
+                sd_event_exit(e, 0);
+
+                return 0;
+        }
+
+        assert_se(sd_radv_stop(ra) >= 0);
+        test_stopped = true;
+
+        return 0;
+}
+
+static void test_ra(void) {
+        sd_event *e;
+        sd_radv *ra;
+        unsigned i;
+
+        printf("* %s\n", __FUNCTION__);
+
+        assert_se(socketpair(AF_UNIX, SOCK_SEQPACKET | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_fd) >= 0);
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        assert_se(sd_radv_new(&ra) >= 0);
+        assert_se(ra);
+
+        assert_se(sd_radv_attach_event(ra, e, 0) >= 0);
+
+        assert_se(sd_radv_set_ifindex(ra, 42) >= 0);
+        assert_se(sd_radv_set_mac(ra, &mac_addr) >= 0);
+        assert_se(sd_radv_set_router_lifetime(ra, 180) >= 0);
+        assert_se(sd_radv_set_hop_limit(ra, 64) >= 0);
+        assert_se(sd_radv_set_managed_information(ra, true) >= 0);
+        assert_se(sd_radv_set_other_information(ra, true) >= 0);
+        assert_se(sd_radv_set_rdnss(ra, 60, &test_rdnss, 1) >= 0);
+        assert_se(sd_radv_set_dnssl(ra, 60, (char **)test_dnssl) >= 0);
+
+        for (i = 0; i < ELEMENTSOF(prefix); i++) {
+                sd_radv_prefix *p;
+
+                printf("Test prefix %u\n", i);
+                assert_se(sd_radv_prefix_new(&p) >= 0);
+
+                assert_se(sd_radv_prefix_set_prefix(p, &prefix[i].address,
+                                                    prefix[i].prefixlen) >= 0);
+                if (prefix[i].valid)
+                        assert_se(sd_radv_prefix_set_valid_lifetime(p, prefix[i].valid) >= 0);
+                if (prefix[i].preferred)
+                        assert_se(sd_radv_prefix_set_preferred_lifetime(p, prefix[i].preferred) >= 0);
+
+                assert_se((sd_radv_add_prefix(ra, p, false) >= 0) == prefix[i].successful);
+                assert_se(sd_radv_add_prefix(ra, p, false) < 0);
+
+                p = sd_radv_prefix_unref(p);
+                assert_se(!p);
+        }
+
+        assert_se(sd_event_add_io(e, &recv_router_advertisement, test_fd[0],
+                                  EPOLLIN, radv_recv, ra) >= 0);
+
+        assert_se(sd_event_add_time_relative(
+                                  e, &test_hangcheck, clock_boottime_or_monotonic(),
+                                  2 *USEC_PER_SEC, 0,
+                                  test_rs_hangcheck, NULL) >= 0);
+
+        assert_se(sd_radv_start(ra) >= 0);
+
+        sd_event_loop(e);
+
+        test_hangcheck = sd_event_source_unref(test_hangcheck);
+
+        ra = sd_radv_unref(ra);
+        assert_se(!ra);
+
+        close(test_fd[0]);
+
+        sd_event_unref(e);
+}
+
+int main(int argc, char *argv[]) {
+
+        test_setup_logging(LOG_DEBUG);
+
+        test_radv_prefix();
+        test_radv();
+        test_ra();
+
+        printf("* done\n");
+        return 0;
+}
diff --git a/src/libsystemd-network/test-ndisc-rs.c b/src/libsystemd-network/test-ndisc-rs.c
new file mode 100644
index 0000000..1b2bba8
--- /dev/null
+++ b/src/libsystemd-network/test-ndisc-rs.c
@@ -0,0 +1,418 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/icmp6.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+
+#include "sd-ndisc.h"
+
+#include "alloc-util.h"
+#include "hexdecoct.h"
+#include "icmp6-util.h"
+#include "socket-util.h"
+#include "strv.h"
+#include "ndisc-internal.h"
+#include "tests.h"
+
+static struct ether_addr mac_addr = {
+        .ether_addr_octet = {'A', 'B', 'C', '1', '2', '3'}
+};
+
+static bool verbose = false;
+static sd_event_source *test_hangcheck;
+static int test_fd[2];
+static sd_ndisc *test_timeout_nd;
+
+typedef int (*send_ra_t)(uint8_t flags);
+static send_ra_t send_ra_function;
+
+static void router_dump(sd_ndisc_router *rt) {
+        struct in6_addr addr;
+        char buf[FORMAT_TIMESTAMP_MAX];
+        uint8_t hop_limit;
+        uint64_t t, flags;
+        uint32_t mtu;
+        uint16_t lifetime;
+        unsigned preference;
+        int r;
+
+        assert_se(rt);
+
+        log_info("--");
+        assert_se(sd_ndisc_router_get_address(rt, &addr) == -ENODATA);
+
+        assert_se(sd_ndisc_router_get_timestamp(rt, CLOCK_REALTIME, &t) >= 0);
+        log_info("Timestamp: %s", format_timestamp(buf, sizeof(buf), t));
+
+        assert_se(sd_ndisc_router_get_timestamp(rt, CLOCK_MONOTONIC, &t) >= 0);
+        log_info("Monotonic: %" PRIu64, t);
+
+        if (sd_ndisc_router_get_hop_limit(rt, &hop_limit) < 0)
+                log_info("No hop limit set");
+        else
+                log_info("Hop limit: %u", hop_limit);
+
+        assert_se(sd_ndisc_router_get_flags(rt, &flags) >= 0);
+        log_info("Flags: <%s|%s>",
+                 flags & ND_RA_FLAG_OTHER ? "OTHER" : "",
+                 flags & ND_RA_FLAG_MANAGED ? "MANAGED" : "");
+
+        assert_se(sd_ndisc_router_get_preference(rt, &preference) >= 0);
+        log_info("Preference: %s",
+                 preference == SD_NDISC_PREFERENCE_LOW ? "low" :
+                 preference == SD_NDISC_PREFERENCE_HIGH ? "high" : "medium");
+
+        assert_se(sd_ndisc_router_get_lifetime(rt, &lifetime) >= 0);
+        log_info("Lifetime: %" PRIu16, lifetime);
+
+        if (sd_ndisc_router_get_mtu(rt, &mtu) < 0)
+                log_info("No MTU set");
+        else
+                log_info("MTU: %" PRIu32, mtu);
+
+        r = sd_ndisc_router_option_rewind(rt);
+        for (;;) {
+                uint8_t type;
+
+                assert_se(r >= 0);
+
+                if (r == 0)
+                        break;
+
+                assert_se(sd_ndisc_router_option_get_type(rt, &type) >= 0);
+
+                log_info(">> Option %u", type);
+
+                switch (type) {
+
+                case SD_NDISC_OPTION_SOURCE_LL_ADDRESS:
+                case SD_NDISC_OPTION_TARGET_LL_ADDRESS: {
+                        _cleanup_free_ char *c = NULL;
+                        const void *p;
+                        size_t n;
+
+                        assert_se(sd_ndisc_router_option_get_raw(rt, &p, &n) >= 0);
+                        assert_se(n > 2);
+                        assert_se(c = hexmem((uint8_t*) p + 2, n - 2));
+
+                        log_info("Address: %s", c);
+                        break;
+                }
+
+                case SD_NDISC_OPTION_PREFIX_INFORMATION: {
+                        uint32_t lifetime_valid, lifetime_preferred;
+                        unsigned prefix_len;
+                        uint8_t pfl;
+                        struct in6_addr a;
+                        char buff[INET6_ADDRSTRLEN];
+
+                        assert_se(sd_ndisc_router_prefix_get_valid_lifetime(rt, &lifetime_valid) >= 0);
+                        log_info("Valid Lifetime: %" PRIu32, lifetime_valid);
+
+                        assert_se(sd_ndisc_router_prefix_get_preferred_lifetime(rt, &lifetime_preferred) >= 0);
+                        log_info("Preferred Lifetime: %" PRIu32, lifetime_preferred);
+
+                        assert_se(sd_ndisc_router_prefix_get_flags(rt, &pfl) >= 0);
+                        log_info("Flags: <%s|%s>",
+                                 pfl & ND_OPT_PI_FLAG_ONLINK ? "ONLINK" : "",
+                                 pfl & ND_OPT_PI_FLAG_AUTO ? "AUTO" : "");
+
+                        assert_se(sd_ndisc_router_prefix_get_prefixlen(rt, &prefix_len) >= 0);
+                        log_info("Prefix Length: %u", prefix_len);
+
+                        assert_se(sd_ndisc_router_prefix_get_address(rt, &a) >= 0);
+                        log_info("Prefix: %s", inet_ntop(AF_INET6, &a, buff, sizeof(buff)));
+
+                        break;
+                }
+
+                case SD_NDISC_OPTION_RDNSS: {
+                        const struct in6_addr *a;
+                        uint32_t lt;
+                        int n, i;
+
+                        n = sd_ndisc_router_rdnss_get_addresses(rt, &a);
+                        assert_se(n > 0);
+
+                        for (i = 0; i < n; i++) {
+                                char buff[INET6_ADDRSTRLEN];
+                                log_info("DNS: %s", inet_ntop(AF_INET6, a + i, buff, sizeof(buff)));
+                        }
+
+                        assert_se(sd_ndisc_router_rdnss_get_lifetime(rt, &lt) >= 0);
+                        log_info("Lifetime: %" PRIu32, lt);
+                        break;
+                }
+
+                case SD_NDISC_OPTION_DNSSL: {
+                        _cleanup_strv_free_ char **l = NULL;
+                        uint32_t lt;
+                        int n, i;
+
+                        n = sd_ndisc_router_dnssl_get_domains(rt, &l);
+                        assert_se(n > 0);
+
+                        for (i = 0; i < n; i++)
+                                log_info("Domain: %s", l[i]);
+
+                        assert_se(sd_ndisc_router_dnssl_get_lifetime(rt, &lt) >= 0);
+                        log_info("Lifetime: %" PRIu32, lt);
+                        break;
+                }}
+
+                r = sd_ndisc_router_option_next(rt);
+        }
+}
+
+static int test_rs_hangcheck(sd_event_source *s, uint64_t usec,
+                             void *userdata) {
+        assert_se(false);
+
+        return 0;
+}
+
+int icmp6_bind_router_solicitation(int ifindex) {
+        assert_se(ifindex == 42);
+
+        if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_fd) < 0)
+                return -errno;
+
+        return test_fd[0];
+}
+
+int icmp6_bind_router_advertisement(int ifindex) {
+        return -ENOSYS;
+}
+
+int icmp6_receive(int fd, void *iov_base, size_t iov_len,
+                  struct in6_addr *dst, triple_timestamp *timestamp) {
+        assert_se(read (fd, iov_base, iov_len) == (ssize_t)iov_len);
+
+        if (timestamp)
+                triple_timestamp_get(timestamp);
+
+        return 0;
+}
+
+static int send_ra(uint8_t flags) {
+        uint8_t advertisement[] = {
+                0x86, 0x00, 0xde, 0x83, 0x40, 0xc0, 0x00, 0xb4,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x03, 0x04, 0x40, 0xc0, 0x00, 0x00, 0x01, 0xf4,
+                0x00, 0x00, 0x01, 0xb8, 0x00, 0x00, 0x00, 0x00,
+                0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe, 0xef,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x19, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c,
+                0x20, 0x01, 0x0d, 0xb8, 0xde, 0xad, 0xbe, 0xef,
+                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+                0x1f, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c,
+                0x03, 0x6c, 0x61, 0x62, 0x05, 0x69, 0x6e, 0x74,
+                0x72, 0x61, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+                0x01, 0x01, 0x78, 0x2b, 0xcb, 0xb3, 0x6d, 0x53,
+        };
+
+        advertisement[5] = flags;
+
+        assert_se(write(test_fd[1], advertisement, sizeof(advertisement)) ==
+                  sizeof(advertisement));
+
+        if (verbose)
+                printf("  sent RA with flag 0x%02x\n", flags);
+
+        return 0;
+}
+
+int icmp6_send_router_solicitation(int s, const struct ether_addr *ether_addr) {
+        if (!send_ra_function)
+                return 0;
+
+        return send_ra_function(0);
+}
+
+static void test_callback(sd_ndisc *nd, sd_ndisc_event event, sd_ndisc_router *rt, void *userdata) {
+        sd_event *e = userdata;
+        static unsigned idx = 0;
+        uint64_t flags_array[] = {
+                0,
+                0,
+                0,
+                ND_RA_FLAG_OTHER,
+                ND_RA_FLAG_MANAGED
+        };
+        uint64_t flags;
+        uint32_t mtu;
+
+        assert_se(nd);
+
+        if (event != SD_NDISC_EVENT_ROUTER)
+                return;
+
+        router_dump(rt);
+
+        assert_se(sd_ndisc_router_get_flags(rt, &flags) >= 0);
+        assert_se(flags == flags_array[idx]);
+        idx++;
+
+        if (verbose)
+                printf("  got event 0x%02" PRIx64 "\n", flags);
+
+        if (idx < ELEMENTSOF(flags_array)) {
+                send_ra(flags_array[idx]);
+                return;
+        }
+
+        assert_se(sd_ndisc_get_mtu(nd, &mtu) == -ENODATA);
+
+        sd_event_exit(e, 0);
+}
+
+static void test_rs(void) {
+        sd_event *e;
+        sd_ndisc *nd;
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        send_ra_function = send_ra;
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        assert_se(sd_ndisc_new(&nd) >= 0);
+        assert_se(nd);
+
+        assert_se(sd_ndisc_attach_event(nd, e, 0) >= 0);
+
+        assert_se(sd_ndisc_set_ifindex(nd, 42) >= 0);
+        assert_se(sd_ndisc_set_mac(nd, &mac_addr) >= 0);
+        assert_se(sd_ndisc_set_callback(nd, test_callback, e) >= 0);
+
+        assert_se(sd_event_add_time_relative(
+                                  e, &test_hangcheck, clock_boottime_or_monotonic(),
+                                  30 * USEC_PER_SEC, 0,
+                                  test_rs_hangcheck, NULL) >= 0);
+
+        assert_se(sd_ndisc_stop(nd) >= 0);
+        assert_se(sd_ndisc_start(nd) >= 0);
+        assert_se(sd_ndisc_start(nd) >= 0);
+        assert_se(sd_ndisc_stop(nd) >= 0);
+
+        assert_se(sd_ndisc_start(nd) >= 0);
+
+        sd_event_loop(e);
+
+        test_hangcheck = sd_event_source_unref(test_hangcheck);
+
+        nd = sd_ndisc_unref(nd);
+        assert_se(!nd);
+
+        close(test_fd[1]);
+
+        sd_event_unref(e);
+}
+
+static int test_timeout_value(uint8_t flags) {
+        static int count = 0;
+        static usec_t last = 0;
+        sd_ndisc *nd = test_timeout_nd;
+        usec_t min, max;
+        char time_string_min[FORMAT_TIMESPAN_MAX];
+        char time_string_nd[FORMAT_TIMESPAN_MAX];
+        char time_string_max[FORMAT_TIMESPAN_MAX];
+
+        assert_se(nd);
+        assert_se(nd->event);
+
+        if (++count >= 20)
+                sd_event_exit(nd->event, 0);
+
+        if (last == 0) {
+                /* initial RT = IRT + RAND*IRT  */
+                min = NDISC_ROUTER_SOLICITATION_INTERVAL -
+                        NDISC_ROUTER_SOLICITATION_INTERVAL / 10;
+                max = NDISC_ROUTER_SOLICITATION_INTERVAL +
+                        NDISC_ROUTER_SOLICITATION_INTERVAL / 10;
+        } else {
+                /* next RT = 2*RTprev + RAND*RTprev */
+                min = 2 * last - last / 10;
+                max = 2 * last + last / 10;
+        }
+
+        /* final RT > MRT */
+        if (last * 2 > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL) {
+                min = NDISC_MAX_ROUTER_SOLICITATION_INTERVAL -
+                        NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 10;
+                max = NDISC_MAX_ROUTER_SOLICITATION_INTERVAL +
+                        NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 10;
+        }
+
+        format_timespan(time_string_min, FORMAT_TIMESPAN_MAX,
+                        min, USEC_PER_MSEC);
+        format_timespan(time_string_nd, FORMAT_TIMESPAN_MAX,
+                        nd->retransmit_time, USEC_PER_MSEC);
+        format_timespan(time_string_max, FORMAT_TIMESPAN_MAX,
+                        max, USEC_PER_MSEC);
+
+        log_info("backoff timeout interval %2d %s%s <= %s <= %s",
+                 count,
+                 (last * 2 > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL)? "(max) ": "",
+                 time_string_min, time_string_nd, time_string_max);
+
+        assert_se(min <= nd->retransmit_time);
+        assert_se(max >= nd->retransmit_time);
+
+        last = nd->retransmit_time;
+
+        assert_se(sd_event_source_set_time(nd->timeout_event_source, 0) >= 0);
+
+        return 0;
+}
+
+static void test_timeout(void) {
+        sd_event *e;
+        sd_ndisc *nd;
+
+        if (verbose)
+                printf("* %s\n", __FUNCTION__);
+
+        send_ra_function = test_timeout_value;
+
+        assert_se(sd_event_new(&e) >= 0);
+
+        assert_se(sd_ndisc_new(&nd) >= 0);
+        assert_se(nd);
+
+        test_timeout_nd = nd;
+
+        assert_se(sd_ndisc_attach_event(nd, e, 0) >= 0);
+
+        assert_se(sd_ndisc_set_ifindex(nd, 42) >= 0);
+        assert_se(sd_ndisc_set_mac(nd, &mac_addr) >= 0);
+
+        assert_se(sd_event_add_time_relative(
+                                  e, &test_hangcheck, clock_boottime_or_monotonic(),
+                                  30 * USEC_PER_SEC, 0,
+                                  test_rs_hangcheck, NULL) >= 0);
+
+        assert_se(sd_ndisc_start(nd) >= 0);
+
+        sd_event_loop(e);
+
+        test_hangcheck = sd_event_source_unref(test_hangcheck);
+
+        nd = sd_ndisc_unref(nd);
+
+        sd_event_unref(e);
+}
+
+int main(int argc, char *argv[]) {
+
+        test_setup_logging(LOG_DEBUG);
+
+        test_rs();
+        test_timeout();
+
+        return 0;
+}
diff --git a/src/libsystemd-network/test-sd-dhcp-lease.c b/src/libsystemd-network/test-sd-dhcp-lease.c
new file mode 100644
index 0000000..9f13226
--- /dev/null
+++ b/src/libsystemd-network/test-sd-dhcp-lease.c
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+
+#include "dhcp-lease-internal.h"
+#include "macro.h"
+#include "string-util.h"
+#include "strv.h"
+
+/* According to RFC1035 section 4.1.4, a domain name in a message can be either:
+ *      - a sequence of labels ending in a zero octet
+ *      - a pointer
+ *      - a sequence of labels ending with a pointer
+ */
+static void test_dhcp_lease_parse_search_domains_basic(void) {
+        int r;
+        _cleanup_strv_free_ char **domains = NULL;
+        static const uint8_t optionbuf[] = {
+                0x03, 'F', 'O', 'O', 0x03, 'B', 'A', 'R', 0x00,
+                0x04, 'A', 'B', 'C', 'D', 0x03, 'E', 'F', 'G', 0x00,
+        };
+
+        r = dhcp_lease_parse_search_domains(optionbuf, sizeof(optionbuf), &domains);
+        assert_se(r == 2);
+        assert_se(streq(domains[0], "FOO.BAR"));
+        assert_se(streq(domains[1], "ABCD.EFG"));
+}
+
+static void test_dhcp_lease_parse_search_domains_ptr(void) {
+        int r;
+        _cleanup_strv_free_ char **domains = NULL;
+        static const uint8_t optionbuf[] = {
+                0x03, 'F', 'O', 'O', 0x00, 0xC0, 0x00,
+        };
+
+        r = dhcp_lease_parse_search_domains(optionbuf, sizeof(optionbuf), &domains);
+        assert_se(r == 2);
+        assert_se(streq(domains[0], "FOO"));
+        assert_se(streq(domains[1], "FOO"));
+}
+
+static void test_dhcp_lease_parse_search_domains_labels_and_ptr(void) {
+        int r;
+        _cleanup_strv_free_ char **domains = NULL;
+        static const uint8_t optionbuf[] = {
+                0x03, 'F', 'O', 'O', 0x03, 'B', 'A', 'R', 0x00,
+                0x03, 'A', 'B', 'C', 0xC0, 0x04,
+        };
+
+        r = dhcp_lease_parse_search_domains(optionbuf, sizeof(optionbuf), &domains);
+        assert_se(r == 2);
+        assert_se(streq(domains[0], "FOO.BAR"));
+        assert_se(streq(domains[1], "ABC.BAR"));
+}
+
+/* Tests for exceptions. */
+
+static void test_dhcp_lease_parse_search_domains_no_data(void) {
+        _cleanup_strv_free_ char **domains = NULL;
+        static const uint8_t optionbuf[3] = {0, 0, 0};
+
+        assert_se(dhcp_lease_parse_search_domains(NULL, 0, &domains) == -ENODATA);
+        assert_se(dhcp_lease_parse_search_domains(optionbuf, 0, &domains) == -ENODATA);
+}
+
+static void test_dhcp_lease_parse_search_domains_loops(void) {
+        _cleanup_strv_free_ char **domains = NULL;
+        static const uint8_t optionbuf[] = {
+                0x03, 'F', 'O', 'O', 0x00, 0x03, 'B', 'A', 'R', 0xC0, 0x06,
+        };
+
+        assert_se(dhcp_lease_parse_search_domains(optionbuf, sizeof(optionbuf), &domains) == -EBADMSG);
+}
+
+static void test_dhcp_lease_parse_search_domains_wrong_len(void) {
+        _cleanup_strv_free_ char **domains = NULL;
+        static const uint8_t optionbuf[] = {
+                0x03, 'F', 'O', 'O', 0x03, 'B', 'A', 'R', 0x00,
+                0x04, 'A', 'B', 'C', 'D', 0x03, 'E', 'F', 'G', 0x00,
+        };
+
+        assert_se(dhcp_lease_parse_search_domains(optionbuf, sizeof(optionbuf) - 5, &domains) == -EBADMSG);
+}
+
+int main(int argc, char *argv[]) {
+        test_dhcp_lease_parse_search_domains_basic();
+        test_dhcp_lease_parse_search_domains_ptr();
+        test_dhcp_lease_parse_search_domains_labels_and_ptr();
+        test_dhcp_lease_parse_search_domains_no_data();
+        test_dhcp_lease_parse_search_domains_loops();
+        test_dhcp_lease_parse_search_domains_wrong_len();
+        return 0;
+}
diff --git a/src/libsystemd/disable-mempool.c b/src/libsystemd/disable-mempool.c
new file mode 100644
index 0000000..1baf91f
--- /dev/null
+++ b/src/libsystemd/disable-mempool.c
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "mempool.h"
+
+const bool mempool_use_allowed = false;
diff --git a/src/libsystemd/libsystemd.pc.in b/src/libsystemd/libsystemd.pc.in
new file mode 100644
index 0000000..74f33b7
--- /dev/null
+++ b/src/libsystemd/libsystemd.pc.in
@@ -0,0 +1,20 @@
+#  SPDX-License-Identifier: LGPL-2.1-or-later
+#
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@rootlibdir@
+includedir=@includedir@
+
+Name: systemd
+Description: systemd Library
+URL: @PROJECT_URL@
+Version: @PROJECT_VERSION@
+Libs: -L${libdir} -lsystemd
+Cflags: -I${includedir}
diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym
new file mode 100644
index 0000000..f83b364
--- /dev/null
+++ b/src/libsystemd/libsystemd.sym
@@ -0,0 +1,738 @@
+/***
+  SPDX-License-Identifier: LGPL-2.1-or-later
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+***/
+
+LIBSYSTEMD_209 {
+global:
+        /* sd-journal */
+        sd_journal_print;
+        sd_journal_printv;
+        sd_journal_send;
+        sd_journal_sendv;
+        sd_journal_stream_fd;
+        sd_journal_open;
+        sd_journal_close;
+        sd_journal_previous;
+        sd_journal_next;
+        sd_journal_previous_skip;
+        sd_journal_next_skip;
+        sd_journal_get_realtime_usec;
+        sd_journal_get_monotonic_usec;
+        sd_journal_get_data;
+        sd_journal_enumerate_data;
+        sd_journal_restart_data;
+        sd_journal_add_match;
+        sd_journal_flush_matches;
+        sd_journal_seek_head;
+        sd_journal_seek_tail;
+        sd_journal_seek_monotonic_usec;
+        sd_journal_seek_realtime_usec;
+        sd_journal_seek_cursor;
+        sd_journal_get_cursor;
+        sd_journal_get_fd;
+        sd_journal_process;
+        sd_journal_print_with_location;
+        sd_journal_printv_with_location;
+        sd_journal_send_with_location;
+        sd_journal_sendv_with_location;
+        sd_journal_get_cutoff_realtime_usec;
+        sd_journal_get_cutoff_monotonic_usec;
+        sd_journal_wait;
+        sd_journal_open_directory;
+        sd_journal_add_disjunction;
+        sd_journal_perror;
+        sd_journal_perror_with_location;
+        sd_journal_get_usage;
+        sd_journal_test_cursor;
+        sd_journal_query_unique;
+        sd_journal_enumerate_unique;
+        sd_journal_restart_unique;
+        sd_journal_get_catalog;
+        sd_journal_get_catalog_for_message_id;
+        sd_journal_set_data_threshold;
+        sd_journal_get_data_threshold;
+        sd_journal_reliable_fd;
+        sd_journal_get_events;
+        sd_journal_get_timeout;
+        sd_journal_add_conjunction;
+        sd_journal_open_files;
+        sd_journal_open_container;
+
+        /* sd-daemon */
+        sd_booted;
+        sd_is_fifo;
+        sd_is_mq;
+        sd_is_socket;
+        sd_is_socket_inet;
+        sd_is_socket_unix;
+        sd_is_special;
+        sd_listen_fds;
+        sd_notify;
+        sd_notifyf;
+        sd_watchdog_enabled;
+
+        /* sd-id128 */
+        sd_id128_to_string;
+        sd_id128_from_string;
+        sd_id128_randomize;
+        sd_id128_get_machine;
+        sd_id128_get_boot;
+
+        /* sd-login */
+        sd_get_seats;
+        sd_get_sessions;
+        sd_get_uids;
+        sd_login_monitor_flush;
+        sd_login_monitor_get_fd;
+        sd_login_monitor_new;
+        sd_login_monitor_unref;
+        sd_pid_get_owner_uid;
+        sd_pid_get_session;
+        sd_seat_can_multi_session;
+        sd_seat_get_active;
+        sd_seat_get_sessions;
+        sd_session_get_seat;
+        sd_session_get_uid;
+        sd_session_is_active;
+        sd_uid_get_seats;
+        sd_uid_get_sessions;
+        sd_uid_get_state;
+        sd_uid_is_on_seat;
+        sd_pid_get_unit;
+        sd_session_get_service;
+        sd_session_get_type;
+        sd_session_get_class;
+        sd_session_get_display;
+        sd_session_get_state;
+        sd_seat_can_tty;
+        sd_seat_can_graphical;
+        sd_session_get_tty;
+        sd_login_monitor_get_events;
+        sd_login_monitor_get_timeout;
+        sd_pid_get_user_unit;
+        sd_pid_get_machine_name;
+        sd_get_machine_names;
+        sd_pid_get_slice;
+        sd_session_get_vt;
+        sd_session_is_remote;
+        sd_session_get_remote_user;
+        sd_session_get_remote_host;
+local:
+       *;
+};
+
+LIBSYSTEMD_211 {
+global:
+        sd_machine_get_class;
+        sd_peer_get_session;
+        sd_peer_get_owner_uid;
+        sd_peer_get_unit;
+        sd_peer_get_user_unit;
+        sd_peer_get_machine_name;
+        sd_peer_get_slice;
+} LIBSYSTEMD_209;
+
+LIBSYSTEMD_213 {
+global:
+        sd_uid_get_display;
+} LIBSYSTEMD_211;
+
+LIBSYSTEMD_214 {
+global:
+        sd_pid_notify;
+        sd_pid_notifyf;
+} LIBSYSTEMD_213;
+
+LIBSYSTEMD_216 {
+global:
+        sd_machine_get_ifindices;
+} LIBSYSTEMD_214;
+
+LIBSYSTEMD_217 {
+global:
+        sd_session_get_desktop;
+} LIBSYSTEMD_216;
+
+LIBSYSTEMD_219 {
+global:
+        sd_pid_notify_with_fds;
+} LIBSYSTEMD_217;
+
+LIBSYSTEMD_220 {
+global:
+        sd_pid_get_user_slice;
+        sd_peer_get_user_slice;
+} LIBSYSTEMD_219;
+
+LIBSYSTEMD_221 {
+global:
+        /* sd-bus */
+        sd_bus_default;
+        sd_bus_default_user;
+        sd_bus_default_system;
+        sd_bus_open;
+        sd_bus_open_user;
+        sd_bus_open_system;
+        sd_bus_open_system_remote;
+        sd_bus_open_system_machine;
+        sd_bus_new;
+        sd_bus_set_address;
+        sd_bus_set_fd;
+        sd_bus_set_exec;
+        sd_bus_get_address;
+        sd_bus_set_bus_client;
+        sd_bus_is_bus_client;
+        sd_bus_set_server;
+        sd_bus_is_server;
+        sd_bus_set_anonymous;
+        sd_bus_is_anonymous;
+        sd_bus_set_trusted;
+        sd_bus_is_trusted;
+        sd_bus_set_monitor;
+        sd_bus_is_monitor;
+        sd_bus_set_description;
+        sd_bus_get_description;
+        sd_bus_negotiate_creds;
+        sd_bus_negotiate_timestamp;
+        sd_bus_negotiate_fds;
+        sd_bus_can_send;
+        sd_bus_get_creds_mask;
+        sd_bus_set_allow_interactive_authorization;
+        sd_bus_get_allow_interactive_authorization;
+        sd_bus_start;
+        sd_bus_close;
+        sd_bus_try_close;
+        sd_bus_ref;
+        sd_bus_unref;
+        sd_bus_is_open;
+        sd_bus_get_bus_id;
+        sd_bus_get_scope;
+        sd_bus_get_tid;
+        sd_bus_get_owner_creds;
+        sd_bus_send;
+        sd_bus_send_to;
+        sd_bus_call;
+        sd_bus_call_async;
+        sd_bus_get_fd;
+        sd_bus_get_events;
+        sd_bus_get_timeout;
+        sd_bus_process;
+        sd_bus_process_priority;
+        sd_bus_wait;
+        sd_bus_flush;
+        sd_bus_get_current_slot;
+        sd_bus_get_current_message;
+        sd_bus_get_current_handler;
+        sd_bus_get_current_userdata;
+        sd_bus_attach_event;
+        sd_bus_detach_event;
+        sd_bus_get_event;
+        sd_bus_add_filter;
+        sd_bus_add_match;
+        sd_bus_add_object;
+        sd_bus_add_fallback;
+        sd_bus_add_object_vtable;
+        sd_bus_add_fallback_vtable;
+        sd_bus_add_node_enumerator;
+        sd_bus_add_object_manager;
+        sd_bus_slot_ref;
+        sd_bus_slot_unref;
+        sd_bus_slot_get_bus;
+        sd_bus_slot_get_userdata;
+        sd_bus_slot_set_userdata;
+        sd_bus_slot_get_description;
+        sd_bus_slot_set_description;
+        sd_bus_slot_get_current_message;
+        sd_bus_slot_get_current_handler;
+        sd_bus_slot_get_current_userdata;
+        sd_bus_message_new_signal;
+        sd_bus_message_new_method_call;
+        sd_bus_message_new_method_return;
+        sd_bus_message_new_method_error;
+        sd_bus_message_new_method_errorf;
+        sd_bus_message_new_method_errno;
+        sd_bus_message_new_method_errnof;
+        sd_bus_message_ref;
+        sd_bus_message_unref;
+        sd_bus_message_get_type;
+        sd_bus_message_get_cookie;
+        sd_bus_message_get_reply_cookie;
+        sd_bus_message_get_priority;
+        sd_bus_message_get_expect_reply;
+        sd_bus_message_get_auto_start;
+        sd_bus_message_get_allow_interactive_authorization;
+        sd_bus_message_get_signature;
+        sd_bus_message_get_path;
+        sd_bus_message_get_interface;
+        sd_bus_message_get_member;
+        sd_bus_message_get_destination;
+        sd_bus_message_get_sender;
+        sd_bus_message_get_error;
+        sd_bus_message_get_errno;
+        sd_bus_message_get_monotonic_usec;
+        sd_bus_message_get_realtime_usec;
+        sd_bus_message_get_seqnum;
+        sd_bus_message_get_bus;
+        sd_bus_message_get_creds;
+        sd_bus_message_is_signal;
+        sd_bus_message_is_method_call;
+        sd_bus_message_is_method_error;
+        sd_bus_message_is_empty;
+        sd_bus_message_has_signature;
+        sd_bus_message_set_expect_reply;
+        sd_bus_message_set_auto_start;
+        sd_bus_message_set_allow_interactive_authorization;
+        sd_bus_message_set_destination;
+        sd_bus_message_set_priority;
+        sd_bus_message_append;
+        sd_bus_message_append_basic;
+        sd_bus_message_append_array;
+        sd_bus_message_append_array_space;
+        sd_bus_message_append_array_iovec;
+        sd_bus_message_append_array_memfd;
+        sd_bus_message_append_string_space;
+        sd_bus_message_append_string_iovec;
+        sd_bus_message_append_string_memfd;
+        sd_bus_message_append_strv;
+        sd_bus_message_open_container;
+        sd_bus_message_close_container;
+        sd_bus_message_copy;
+        sd_bus_message_read;
+        sd_bus_message_read_basic;
+        sd_bus_message_read_array;
+        sd_bus_message_read_strv;
+        sd_bus_message_skip;
+        sd_bus_message_enter_container;
+        sd_bus_message_exit_container;
+        sd_bus_message_peek_type;
+        sd_bus_message_verify_type;
+        sd_bus_message_at_end;
+        sd_bus_message_rewind;
+        sd_bus_get_unique_name;
+        sd_bus_request_name;
+        sd_bus_release_name;
+        sd_bus_list_names;
+        sd_bus_get_name_creds;
+        sd_bus_get_name_machine_id;
+        sd_bus_call_method;
+        sd_bus_call_method_async;
+        sd_bus_get_property;
+        sd_bus_get_property_trivial;
+        sd_bus_get_property_string;
+        sd_bus_get_property_strv;
+        sd_bus_set_property;
+        sd_bus_reply_method_return;
+        sd_bus_reply_method_error;
+        sd_bus_reply_method_errorf;
+        sd_bus_reply_method_errno;
+        sd_bus_reply_method_errnof;
+        sd_bus_emit_signal;
+        sd_bus_emit_properties_changed_strv;
+        sd_bus_emit_properties_changed;
+        sd_bus_emit_interfaces_added_strv;
+        sd_bus_emit_interfaces_added;
+        sd_bus_emit_interfaces_removed_strv;
+        sd_bus_emit_interfaces_removed;
+        sd_bus_query_sender_creds;
+        sd_bus_query_sender_privilege;
+        sd_bus_creds_new_from_pid;
+        sd_bus_creds_ref;
+        sd_bus_creds_unref;
+        sd_bus_creds_get_mask;
+        sd_bus_creds_get_augmented_mask;
+        sd_bus_creds_get_pid;
+        sd_bus_creds_get_ppid;
+        sd_bus_creds_get_tid;
+        sd_bus_creds_get_uid;
+        sd_bus_creds_get_euid;
+        sd_bus_creds_get_suid;
+        sd_bus_creds_get_fsuid;
+        sd_bus_creds_get_gid;
+        sd_bus_creds_get_egid;
+        sd_bus_creds_get_sgid;
+        sd_bus_creds_get_fsgid;
+        sd_bus_creds_get_supplementary_gids;
+        sd_bus_creds_get_comm;
+        sd_bus_creds_get_tid_comm;
+        sd_bus_creds_get_exe;
+        sd_bus_creds_get_cmdline;
+        sd_bus_creds_get_cgroup;
+        sd_bus_creds_get_unit;
+        sd_bus_creds_get_slice;
+        sd_bus_creds_get_user_unit;
+        sd_bus_creds_get_user_slice;
+        sd_bus_creds_get_session;
+        sd_bus_creds_get_owner_uid;
+        sd_bus_creds_has_effective_cap;
+        sd_bus_creds_has_permitted_cap;
+        sd_bus_creds_has_inheritable_cap;
+        sd_bus_creds_has_bounding_cap;
+        sd_bus_creds_get_selinux_context;
+        sd_bus_creds_get_audit_session_id;
+        sd_bus_creds_get_audit_login_uid;
+        sd_bus_creds_get_tty;
+        sd_bus_creds_get_unique_name;
+        sd_bus_creds_get_well_known_names;
+        sd_bus_creds_get_description;
+        sd_bus_error_free;
+        sd_bus_error_set;
+        sd_bus_error_setf;
+        sd_bus_error_set_const;
+        sd_bus_error_set_errno;
+        sd_bus_error_set_errnof;
+        sd_bus_error_set_errnofv;
+        sd_bus_error_get_errno;
+        sd_bus_error_copy;
+        sd_bus_error_is_set;
+        sd_bus_error_has_name;
+        sd_bus_error_add_map;
+        sd_bus_path_encode;
+        sd_bus_path_decode;
+        sd_bus_track_new;
+        sd_bus_track_ref;
+        sd_bus_track_unref;
+        sd_bus_track_get_bus;
+        sd_bus_track_get_userdata;
+        sd_bus_track_set_userdata;
+        sd_bus_track_add_sender;
+        sd_bus_track_remove_sender;
+        sd_bus_track_add_name;
+        sd_bus_track_remove_name;
+        sd_bus_track_count;
+        sd_bus_track_contains;
+        sd_bus_track_first;
+        sd_bus_track_next;
+
+        /* sd-event */
+        sd_event_default;
+        sd_event_new;
+        sd_event_ref;
+        sd_event_unref;
+        sd_event_add_io;
+        sd_event_add_time;
+        sd_event_add_signal;
+        sd_event_add_child;
+        sd_event_add_defer;
+        sd_event_add_post;
+        sd_event_add_exit;
+        sd_event_prepare;
+        sd_event_wait;
+        sd_event_dispatch;
+        sd_event_run;
+        sd_event_loop;
+        sd_event_exit;
+        sd_event_now;
+        sd_event_get_fd;
+        sd_event_get_state;
+        sd_event_get_tid;
+        sd_event_get_exit_code;
+        sd_event_set_watchdog;
+        sd_event_get_watchdog;
+        sd_event_source_ref;
+        sd_event_source_unref;
+        sd_event_source_get_event;
+        sd_event_source_get_userdata;
+        sd_event_source_set_userdata;
+        sd_event_source_set_description;
+        sd_event_source_get_description;
+        sd_event_source_set_prepare;
+        sd_event_source_get_pending;
+        sd_event_source_get_priority;
+        sd_event_source_set_priority;
+        sd_event_source_get_enabled;
+        sd_event_source_set_enabled;
+        sd_event_source_get_io_fd;
+        sd_event_source_set_io_fd;
+        sd_event_source_get_io_events;
+        sd_event_source_set_io_events;
+        sd_event_source_get_io_revents;
+        sd_event_source_get_time;
+        sd_event_source_set_time;
+        sd_event_source_set_time_accuracy;
+        sd_event_source_get_time_accuracy;
+        sd_event_source_get_time_clock;
+        sd_event_source_get_signal;
+        sd_event_source_get_child_pid;
+} LIBSYSTEMD_220;
+
+LIBSYSTEMD_222 {
+global:
+        /* sd-bus */
+        sd_bus_emit_object_added;
+        sd_bus_emit_object_removed;
+        sd_bus_flush_close_unref;
+} LIBSYSTEMD_221;
+
+LIBSYSTEMD_226 {
+global:
+        sd_pid_get_cgroup;
+        sd_peer_get_cgroup;
+} LIBSYSTEMD_222;
+
+LIBSYSTEMD_227 {
+global:
+        sd_bus_default_flush_close;
+        sd_bus_path_decode_many;
+        sd_bus_path_encode_many;
+        sd_listen_fds_with_names;
+} LIBSYSTEMD_226;
+
+LIBSYSTEMD_229 {
+global:
+        sd_journal_has_runtime_files;
+        sd_journal_has_persistent_files;
+        sd_journal_enumerate_fields;
+        sd_journal_restart_fields;
+} LIBSYSTEMD_227;
+
+LIBSYSTEMD_230 {
+global:
+        sd_journal_open_directory_fd;
+        sd_journal_open_files_fd;
+} LIBSYSTEMD_229;
+
+LIBSYSTEMD_231 {
+global:
+        sd_event_get_iteration;
+} LIBSYSTEMD_230;
+
+LIBSYSTEMD_232 {
+global:
+        sd_bus_track_set_recursive;
+        sd_bus_track_get_recursive;
+        sd_bus_track_count_name;
+        sd_bus_track_count_sender;
+        sd_bus_set_exit_on_disconnect;
+        sd_bus_get_exit_on_disconnect;
+        sd_id128_get_invocation;
+} LIBSYSTEMD_231;
+
+LIBSYSTEMD_233 {
+global:
+        sd_id128_get_machine_app_specific;
+        sd_is_socket_sockaddr;
+} LIBSYSTEMD_232;
+
+LIBSYSTEMD_234 {
+global:
+        sd_bus_message_appendv;
+} LIBSYSTEMD_233;
+
+LIBSYSTEMD_236 {
+global:
+        sd_bus_message_new;
+        sd_bus_message_seal;
+} LIBSYSTEMD_234;
+
+LIBSYSTEMD_237 {
+global:
+        sd_bus_set_watch_bind;
+        sd_bus_get_watch_bind;
+        sd_bus_request_name_async;
+        sd_bus_release_name_async;
+        sd_bus_add_match_async;
+        sd_bus_match_signal;
+        sd_bus_match_signal_async;
+        sd_bus_is_ready;
+        sd_bus_set_connected_signal;
+        sd_bus_get_connected_signal;
+        sd_bus_set_sender;
+        sd_bus_get_sender;
+        sd_bus_message_set_sender;
+        sd_event_source_get_io_fd_own;
+        sd_event_source_set_io_fd_own;
+} LIBSYSTEMD_236;
+
+LIBSYSTEMD_238 {
+global:
+        sd_bus_get_n_queued_read;
+        sd_bus_get_n_queued_write;
+} LIBSYSTEMD_237;
+
+LIBSYSTEMD_239 {
+global:
+        sd_bus_open_with_description;
+        sd_bus_open_user_with_description;
+        sd_bus_open_system_with_description;
+        sd_bus_slot_get_floating;
+        sd_bus_slot_set_floating;
+        sd_bus_slot_get_destroy_callback;
+        sd_bus_slot_set_destroy_callback;
+        sd_bus_track_get_destroy_callback;
+        sd_bus_track_set_destroy_callback;
+        sd_event_add_inotify;
+        sd_event_source_get_inotify_mask;
+        sd_event_source_set_destroy_callback;
+        sd_event_source_get_destroy_callback;
+} LIBSYSTEMD_238;
+
+LIBSYSTEMD_240 {
+global:
+        sd_bus_message_readv;
+        sd_bus_set_method_call_timeout;
+        sd_bus_get_method_call_timeout;
+
+        sd_bus_error_move;
+
+        sd_bus_set_close_on_exit;
+        sd_bus_get_close_on_exit;
+
+        sd_device_ref;
+        sd_device_unref;
+
+        sd_device_new_from_syspath;
+        sd_device_new_from_devnum;
+        sd_device_new_from_subsystem_sysname;
+        sd_device_new_from_device_id;
+
+        sd_device_get_parent;
+        sd_device_get_parent_with_subsystem_devtype;
+
+        sd_device_get_syspath;
+        sd_device_get_subsystem;
+        sd_device_get_devtype;
+        sd_device_get_devnum;
+        sd_device_get_ifindex;
+        sd_device_get_driver;
+        sd_device_get_devpath;
+        sd_device_get_devname;
+        sd_device_get_sysname;
+        sd_device_get_sysnum;
+
+        sd_device_get_is_initialized;
+        sd_device_get_usec_since_initialized;
+
+        sd_device_get_tag_first;
+        sd_device_get_tag_next;
+        sd_device_get_devlink_first;
+        sd_device_get_devlink_next;
+        sd_device_get_property_first;
+        sd_device_get_property_next;
+        sd_device_get_sysattr_first;
+        sd_device_get_sysattr_next;
+
+        sd_device_has_tag;
+        sd_device_get_property_value;
+        sd_device_get_sysattr_value;
+
+        sd_device_set_sysattr_value;
+
+        sd_device_enumerator_new;
+        sd_device_enumerator_ref;
+        sd_device_enumerator_unref;
+
+        sd_device_enumerator_get_device_first;
+        sd_device_enumerator_get_device_next;
+        sd_device_enumerator_get_subsystem_first;
+        sd_device_enumerator_get_subsystem_next;
+
+        sd_device_enumerator_add_match_subsystem;
+        sd_device_enumerator_add_match_sysattr;
+        sd_device_enumerator_add_match_property;
+        sd_device_enumerator_add_match_sysname;
+        sd_device_enumerator_add_match_tag;
+        sd_device_enumerator_add_match_parent;
+        sd_device_enumerator_allow_uninitialized;
+
+        sd_hwdb_ref;
+        sd_hwdb_unref;
+
+        sd_hwdb_new;
+
+        sd_hwdb_get;
+
+        sd_hwdb_seek;
+        sd_hwdb_enumerate;
+
+        sd_id128_get_boot_app_specific;
+
+        sd_device_monitor_new;
+        sd_device_monitor_ref;
+        sd_device_monitor_unref;
+
+        sd_device_monitor_set_receive_buffer_size;
+        sd_device_monitor_attach_event;
+        sd_device_monitor_detach_event;
+        sd_device_monitor_get_event;
+        sd_device_monitor_get_event_source;
+        sd_device_monitor_start;
+        sd_device_monitor_stop;
+
+        sd_device_monitor_filter_add_match_subsystem_devtype;
+        sd_device_monitor_filter_add_match_tag;
+        sd_device_monitor_filter_update;
+        sd_device_monitor_filter_remove;
+
+        sd_event_source_get_floating;
+        sd_event_source_set_floating;
+} LIBSYSTEMD_239;
+
+LIBSYSTEMD_241 {
+global:
+        sd_bus_close_unref;
+} LIBSYSTEMD_240;
+
+LIBSYSTEMD_243 {
+global:
+        sd_bus_object_vtable_format;
+        sd_event_source_disable_unref;
+} LIBSYSTEMD_241;
+
+LIBSYSTEMD_245 {
+global:
+        sd_bus_enqueue_for_read;
+        sd_bus_message_dump;
+        sd_bus_message_sensitive;
+        sd_event_add_child_pidfd;
+        sd_event_source_get_child_pidfd;
+        sd_event_source_get_child_pidfd_own;
+        sd_event_source_set_child_pidfd_own;
+        sd_event_source_get_child_process_own;
+        sd_event_source_set_child_process_own;
+        sd_event_source_send_child_signal;
+        sd_journal_open_namespace;
+} LIBSYSTEMD_243;
+
+LIBSYSTEMD_246 {
+global:
+        sd_bus_interface_name_is_valid;
+        sd_bus_service_name_is_valid;
+        sd_bus_member_name_is_valid;
+        sd_bus_object_path_is_valid;
+
+        sd_bus_call_methodv;
+        sd_bus_call_method_asyncv;
+        sd_bus_emit_signalv;
+        sd_bus_reply_method_errnofv;
+        sd_bus_reply_method_errorfv;
+        sd_bus_reply_method_returnv;
+        sd_bus_set_propertyv;
+
+        sd_path_lookup;
+        sd_path_lookup_strv;
+
+        sd_notify_barrier;
+
+        sd_journal_enumerate_available_data;
+        sd_journal_enumerate_available_unique;
+} LIBSYSTEMD_245;
+
+LIBSYSTEMD_247 {
+global:
+        sd_event_add_time_relative;
+        sd_event_source_set_time_relative;
+        sd_event_source_get_exit_on_failure;
+        sd_event_source_set_exit_on_failure;
+
+        sd_bus_error_has_names_sentinel;
+
+        sd_device_get_current_tag_first;
+        sd_device_get_current_tag_next;
+        sd_device_has_current_tag;
+        sd_device_set_sysattr_valuef;
+} LIBSYSTEMD_246;
diff --git a/src/libsystemd/meson.build b/src/libsystemd/meson.build
new file mode 100644
index 0000000..50716f7
--- /dev/null
+++ b/src/libsystemd/meson.build
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+id128_sources = files('''
+        sd-id128/id128-util.c
+        sd-id128/id128-util.h
+        sd-id128/sd-id128.c
+'''.split())
+
+sd_daemon_sources = files('sd-daemon/sd-daemon.c')
+
+sd_event_sources = files('''
+        sd-event/event-source.h
+        sd-event/event-util.c
+        sd-event/event-util.h
+        sd-event/sd-event.c
+'''.split())
+
+sd_login_sources = files('sd-login/sd-login.c')
+
+libsystemd_sources = files('''
+        sd-bus/bus-common-errors.c
+        sd-bus/bus-common-errors.h
+        sd-bus/bus-container.c
+        sd-bus/bus-container.h
+        sd-bus/bus-control.c
+        sd-bus/bus-control.h
+        sd-bus/bus-convenience.c
+        sd-bus/bus-creds.c
+        sd-bus/bus-creds.h
+        sd-bus/bus-dump.c
+        sd-bus/bus-dump.h
+        sd-bus/bus-error.c
+        sd-bus/bus-error.h
+        sd-bus/bus-gvariant.c
+        sd-bus/bus-gvariant.h
+        sd-bus/bus-internal.c
+        sd-bus/bus-internal.h
+        sd-bus/bus-introspect.c
+        sd-bus/bus-introspect.h
+        sd-bus/bus-kernel.c
+        sd-bus/bus-kernel.h
+        sd-bus/bus-match.c
+        sd-bus/bus-match.h
+        sd-bus/bus-message.c
+        sd-bus/bus-message.h
+        sd-bus/bus-objects.c
+        sd-bus/bus-objects.h
+        sd-bus/bus-protocol.h
+        sd-bus/bus-signature.c
+        sd-bus/bus-signature.h
+        sd-bus/bus-slot.c
+        sd-bus/bus-slot.h
+        sd-bus/bus-socket.c
+        sd-bus/bus-socket.h
+        sd-bus/bus-track.c
+        sd-bus/bus-track.h
+        sd-bus/bus-type.c
+        sd-bus/bus-type.h
+        sd-bus/sd-bus.c
+        sd-device/device-enumerator-private.h
+        sd-device/device-enumerator.c
+        sd-device/device-internal.h
+        sd-device/device-monitor-private.h
+        sd-device/device-monitor.c
+        sd-device/device-private.c
+        sd-device/device-private.h
+        sd-device/device-util.h
+        sd-device/sd-device.c
+        sd-hwdb/hwdb-internal.h
+        sd-hwdb/hwdb-util.c
+        sd-hwdb/hwdb-util.h
+        sd-hwdb/sd-hwdb.c
+        sd-netlink/generic-netlink.c
+        sd-netlink/generic-netlink.h
+        sd-netlink/netlink-internal.h
+        sd-netlink/netlink-message.c
+        sd-netlink/netlink-slot.c
+        sd-netlink/netlink-slot.h
+        sd-netlink/netlink-socket.c
+        sd-netlink/netlink-types.c
+        sd-netlink/netlink-types.h
+        sd-netlink/netlink-util.c
+        sd-netlink/netlink-util.h
+        sd-netlink/rtnl-message.c
+        sd-netlink/sd-netlink.c
+        sd-network/network-util.c
+        sd-network/network-util.h
+        sd-network/sd-network.c
+        sd-path/sd-path.c
+        sd-resolve/resolve-private.h
+        sd-resolve/sd-resolve.c
+        sd-utf8/sd-utf8.c
+'''.split()) + id128_sources + sd_daemon_sources + sd_event_sources + sd_login_sources
+
+disable_mempool_c = files('disable-mempool.c')
+
+libsystemd_c_args = ['-fvisibility=default']
+
+libsystemd_static = static_library(
+        'systemd_static',
+        libsystemd_sources,
+        install : false,
+        include_directories : includes,
+        link_with : libbasic,
+        dependencies : [threads,
+                        librt],
+        c_args : libsystemd_c_args)
+
+libsystemd_sym = 'src/libsystemd/libsystemd.sym'
+
+configure_file(
+        input : 'libsystemd.pc.in',
+        output : 'libsystemd.pc',
+        configuration : substs,
+        install_dir : pkgconfiglibdir == 'no' ? '' : pkgconfiglibdir)
diff --git a/src/libsystemd/sd-bus/GVARIANT-SERIALIZATION b/src/libsystemd/sd-bus/GVARIANT-SERIALIZATION
new file mode 100644
index 0000000..973a063
--- /dev/null
+++ b/src/libsystemd/sd-bus/GVARIANT-SERIALIZATION
@@ -0,0 +1,105 @@
+How we use GVariant for serializing D-Bus messages
+--------------------------------------------------
+
+We stay close to the original dbus1 framing as possible, but make
+certain changes to adapt for GVariant. dbus1 has the following
+framing:
+
+    1. A fixed header of "yyyyuu"
+    2. Additional header fields of "a(yv)"
+    3. Padding with NUL bytes to pad up to next 8byte boundary
+    4. The body
+
+Note that the body is not padded at the end, the complete message
+hence might have a non-aligned size. Reading multiple messages at once
+will hence result in possibly unaligned messages in memory.
+
+The header consists of the following:
+
+    y  Endianness, 'l' or 'B'
+    y  Message Type
+    y  Flags
+    y  Protocol version, '1'
+    u  Length of the body, i.e. the length of part 4 above
+    u  32bit Serial number
+
+    = 12 bytes
+
+This header is then followed by the fields array, whose first value is
+a 32bit array size.
+
+When using GVariant we keep the basic structure in place, only
+slightly alter the header, and define protocol version '2'. The new
+header:
+
+    y  Endianness, 'l' or 'B'
+    y  Message Type
+    y  Flags
+    y  Protocol version, '2'
+    u  Reserved, must be 0
+    t  64bit Cookie
+
+    = 16 bytes
+
+This is then followed by the GVariant fields array ("a{tv}"), and
+finally the actual body as variant (v). Putting this altogether a
+packet on dbus2 hence qualifies as a fully compliant GVariant
+structure of (yyyyuta{tv}v).
+
+For details on gvariant, see:
+
+https://people.gnome.org/~desrt/gvariant-serialisation.pdf
+
+Regarding the framing of dbus2, also see:
+
+https://wiki.gnome.org/Projects/GLib/GDBus/Version2
+
+The first four bytes of the header are defined the same way for dbus1
+and dbus2. The first bytes contain the endianness field and the
+protocol version, so that the remainder of the message can be safely
+made sense of just by looking at the first 32bit.
+
+Note that the length of the body is no longer included in the header
+on dbus2! In fact, the message size must be known in advance, from the
+underlying transport in order to parse dbus2 messages, while it is
+directly included in dbus1 message headers. This change of semantics
+is an effect of GVariant's basic design.
+
+The serial number has been renamed cookie and has been extended from
+32bit to 64bit. It is recommended to avoid the higher 32bit of the
+cookie field though, to simplify compatibility with dbus1 peers. Note
+that not only the cookie/serial field in the fixed header, but also
+the reply_cookie/reply_serial additional header field has been
+increased from 32bit to 64bit, too!
+
+The header field identifiers have been extended from 8bit to
+64bit. This has been done to simplify things, and has no effect
+on the serialization size, as due to alignment for each 8bit
+header field identifier 56 bits of padding had to be added.
+
+Note that the header size changed, due to these changes. However,
+consider that on dbus1 the beginning of the fields array contains the
+32bit array size (since that is how arrays are encoded on dbus1),
+thus, if one considers that size part of the header, instead of the
+array, the size of the header on dbus1 and dbus2 stays identical, at
+16 bytes.
+
+              0               4               8               12              16
+      Common: | E | T | F | V | ...
+
+       dbus1: |  (as above)   | Body Length   | Serial        | Fields Length | Fields array ...
+
+    gvariant: |  (as above)   | Reserved      | Cookie                        | Fields array ...
+
+And that's already it.
+
+Note: To simplify parsing, valid dbus2 messages must include the entire
+      fixed header and additional header fields in a single non-memfd
+      message part. Also, the signature string of the body variant all the
+      way to the end of the message must be in a single non-memfd part
+      too. The parts for this extended header and footer can be the same
+      one, and can also continue any amount of additional body bytes.
+
+Note: The GVariant "MAYBE" type is not supported, so that messages can
+      be fully converted forth and back between dbus1 and gvariant
+      representations.
diff --git a/src/libsystemd/sd-bus/bus-common-errors.c b/src/libsystemd/sd-bus/bus-common-errors.c
new file mode 100644
index 0000000..ef1fa37
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-common-errors.c
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+
+#include "sd-bus.h"
+
+#include "bus-common-errors.h"
+#include "bus-error.h"
+
+BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_common_errors[] = {
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_UNIT,                 ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_UNIT_FOR_PID,              ESRCH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_UNIT_FOR_INVOCATION_ID,    ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_UNIT_EXISTS,                  EEXIST),
+        SD_BUS_ERROR_MAP(BUS_ERROR_LOAD_FAILED,                  EIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_BAD_UNIT_SETTING,             ENOEXEC),
+        SD_BUS_ERROR_MAP(BUS_ERROR_JOB_FAILED,                   EREMOTEIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_JOB,                  ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NOT_SUBSCRIBED,               EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_ALREADY_SUBSCRIBED,           EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_ONLY_BY_DEPENDENCY,           EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TRANSACTION_JOBS_CONFLICTING, EDEADLK),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TRANSACTION_ORDER_IS_CYCLIC,  EDEADLK),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TRANSACTION_IS_DESTRUCTIVE,   EDEADLK),
+        SD_BUS_ERROR_MAP(BUS_ERROR_UNIT_MASKED,                  ERFKILL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_UNIT_GENERATED,               EADDRNOTAVAIL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_UNIT_LINKED,                  ELOOP),
+        SD_BUS_ERROR_MAP(BUS_ERROR_JOB_TYPE_NOT_APPLICABLE,      EBADR),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_ISOLATION,                 EPERM),
+        SD_BUS_ERROR_MAP(BUS_ERROR_SHUTTING_DOWN,                ECANCELED),
+        SD_BUS_ERROR_MAP(BUS_ERROR_SCOPE_NOT_RUNNING,            EHOSTDOWN),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_DYNAMIC_USER,         ESRCH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NOT_REFERENCED,               EUNATCH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_DISK_FULL,                    ENOSPC),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_MACHINE,              ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_IMAGE,                ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_MACHINE_FOR_PID,           ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_MACHINE_EXISTS,               EEXIST),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_PRIVATE_NETWORKING,        ENOSYS),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_USER_MAPPING,         ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_GROUP_MAPPING,        ENXIO),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_PORTABLE_IMAGE,       ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_BAD_PORTABLE_IMAGE_TYPE,      EMEDIUMTYPE),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_SESSION,              ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SESSION_FOR_PID,           ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_USER,                 ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_USER_FOR_PID,              ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_SEAT,                 ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_SESSION_NOT_ON_SEAT,          EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NOT_IN_CONTROL,               EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_DEVICE_IS_TAKEN,              EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_DEVICE_NOT_TAKEN,             EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_OPERATION_IN_PROGRESS,        EINPROGRESS),
+        SD_BUS_ERROR_MAP(BUS_ERROR_SLEEP_VERB_NOT_SUPPORTED,     EOPNOTSUPP),
+        SD_BUS_ERROR_MAP(BUS_ERROR_SESSION_BUSY,                 EBUSY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NOT_YOUR_DEVICE,              EPERM),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_AUTOMATIC_TIME_SYNC_ENABLED,  EALREADY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_NTP_SUPPORT,               EOPNOTSUPP),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_PROCESS,              ESRCH),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_NAME_SERVERS,              ESRCH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_INVALID_REPLY,                EINVAL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_RR,                   ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_CNAME_LOOP,                   EDEADLK),
+        SD_BUS_ERROR_MAP(BUS_ERROR_ABORTED,                      ECANCELED),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_SERVICE,              EUNATCH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_DNSSEC_FAILED,                EHOSTUNREACH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_TRUST_ANCHOR,              EHOSTUNREACH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_RR_TYPE_UNSUPPORTED,          EOPNOTSUPP),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_LINK,                 ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_LINK_BUSY,                    EBUSY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NETWORK_DOWN,                 ENETDOWN),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_DNSSD_SERVICE,        ENOENT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_DNSSD_SERVICE_EXISTS,         EEXIST),
+
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "FORMERR",               EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "SERVFAIL",              EHOSTDOWN),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "NXDOMAIN",              ENXIO),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "NOTIMP",                ENOSYS),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "REFUSED",               EACCES),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "YXDOMAIN",              EEXIST),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "YRRSET",                EEXIST),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "NXRRSET",               ENOENT),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "NOTAUTH",               EACCES),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "NOTZONE",               EREMOTE),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADVERS",               EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADKEY",                EKEYREJECTED),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADTIME",               EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADMODE",               EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADNAME",               EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADALG",                EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADTRUNC",              EBADMSG),
+        SD_BUS_ERROR_MAP(_BUS_ERROR_DNS "BADCOOKIE",             EBADR),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_TRANSFER,             ENXIO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TRANSFER_IN_PROGRESS,         EBUSY),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_PRODUCT_UUID,              EOPNOTSUPP),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_SPEED_METER_INACTIVE,         EOPNOTSUPP),
+        SD_BUS_ERROR_MAP(BUS_ERROR_UNMANAGED_INTERFACE,          EOPNOTSUPP),
+
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_HOME,                 EEXIST),
+        SD_BUS_ERROR_MAP(BUS_ERROR_UID_IN_USE,                   EEXIST),
+        SD_BUS_ERROR_MAP(BUS_ERROR_USER_NAME_EXISTS,             EEXIST),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_EXISTS,                  EEXIST),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_ALREADY_ACTIVE,          EALREADY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_ALREADY_FIXATED,         EALREADY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_UNFIXATED,               EADDRNOTAVAIL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_NOT_ACTIVE,              EALREADY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_ABSENT,                  EREMOTE),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_BUSY,                    EBUSY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_BAD_PASSWORD,                 ENOKEY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_LOW_PASSWORD_QUALITY,         EUCLEAN),
+        SD_BUS_ERROR_MAP(BUS_ERROR_BAD_PASSWORD_AND_NO_TOKEN,    EBADSLT),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_PIN_NEEDED,             ENOANO),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_PROTECTED_AUTHENTICATION_PATH_NEEDED, ERFKILL),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED,   EMEDIUMTYPE),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_ACTION_TIMEOUT,         ENOSTR),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_PIN_LOCKED,             EOWNERDEAD),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_BAD_PIN,                ENOLCK),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_BAD_PIN_FEW_TRIES_LEFT, ETOOMANYREFS),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOKEN_BAD_PIN_ONE_TRY_LEFT,   EUCLEAN),
+        SD_BUS_ERROR_MAP(BUS_ERROR_BAD_SIGNATURE,                EKEYREJECTED),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_RECORD_MISMATCH,         EUCLEAN),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_RECORD_DOWNGRADE,        ESTALE),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_RECORD_SIGNED,           EROFS),
+        SD_BUS_ERROR_MAP(BUS_ERROR_BAD_HOME_SIZE,                ERANGE),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_PRIVATE_KEY,               ENOPKG),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_LOCKED,                  ENOEXEC),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_NOT_LOCKED,              ENOEXEC),
+        SD_BUS_ERROR_MAP(BUS_ERROR_TOO_MANY_OPERATIONS,          ENOBUFS),
+        SD_BUS_ERROR_MAP(BUS_ERROR_AUTHENTICATION_LIMIT_HIT,     ETOOMANYREFS),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_CANT_AUTHENTICATE,       EKEYREVOKED),
+
+        SD_BUS_ERROR_MAP_END
+};
diff --git a/src/libsystemd/sd-bus/bus-common-errors.h b/src/libsystemd/sd-bus/bus-common-errors.h
new file mode 100644
index 0000000..7e5be17
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-common-errors.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "bus-error.h"
+
+#define BUS_ERROR_NO_SUCH_UNIT "org.freedesktop.systemd1.NoSuchUnit"
+#define BUS_ERROR_NO_UNIT_FOR_PID "org.freedesktop.systemd1.NoUnitForPID"
+#define BUS_ERROR_NO_UNIT_FOR_INVOCATION_ID "org.freedesktop.systemd1.NoUnitForInvocationID"
+#define BUS_ERROR_UNIT_EXISTS "org.freedesktop.systemd1.UnitExists"
+#define BUS_ERROR_LOAD_FAILED "org.freedesktop.systemd1.LoadFailed"
+#define BUS_ERROR_BAD_UNIT_SETTING "org.freedesktop.systemd1.BadUnitSetting"
+#define BUS_ERROR_JOB_FAILED "org.freedesktop.systemd1.JobFailed"
+#define BUS_ERROR_NO_SUCH_JOB "org.freedesktop.systemd1.NoSuchJob"
+#define BUS_ERROR_NOT_SUBSCRIBED "org.freedesktop.systemd1.NotSubscribed"
+#define BUS_ERROR_ALREADY_SUBSCRIBED "org.freedesktop.systemd1.AlreadySubscribed"
+#define BUS_ERROR_ONLY_BY_DEPENDENCY "org.freedesktop.systemd1.OnlyByDependency"
+#define BUS_ERROR_TRANSACTION_JOBS_CONFLICTING "org.freedesktop.systemd1.TransactionJobsConflicting"
+#define BUS_ERROR_TRANSACTION_ORDER_IS_CYCLIC "org.freedesktop.systemd1.TransactionOrderIsCyclic"
+#define BUS_ERROR_TRANSACTION_IS_DESTRUCTIVE "org.freedesktop.systemd1.TransactionIsDestructive"
+#define BUS_ERROR_UNIT_MASKED "org.freedesktop.systemd1.UnitMasked"
+#define BUS_ERROR_UNIT_GENERATED "org.freedesktop.systemd1.UnitGenerated"
+#define BUS_ERROR_UNIT_LINKED "org.freedesktop.systemd1.UnitLinked"
+#define BUS_ERROR_JOB_TYPE_NOT_APPLICABLE "org.freedesktop.systemd1.JobTypeNotApplicable"
+#define BUS_ERROR_NO_ISOLATION "org.freedesktop.systemd1.NoIsolation"
+#define BUS_ERROR_SHUTTING_DOWN "org.freedesktop.systemd1.ShuttingDown"
+#define BUS_ERROR_SCOPE_NOT_RUNNING "org.freedesktop.systemd1.ScopeNotRunning"
+#define BUS_ERROR_NO_SUCH_DYNAMIC_USER "org.freedesktop.systemd1.NoSuchDynamicUser"
+#define BUS_ERROR_NOT_REFERENCED "org.freedesktop.systemd1.NotReferenced"
+#define BUS_ERROR_DISK_FULL "org.freedesktop.systemd1.DiskFull"
+#define BUS_ERROR_NOTHING_TO_CLEAN "org.freedesktop.systemd1.NothingToClean"
+#define BUS_ERROR_UNIT_BUSY "org.freedesktop.systemd1.UnitBusy"
+#define BUS_ERROR_UNIT_INACTIVE "org.freedesktop.systemd1.UnitInactive"
+
+#define BUS_ERROR_NO_SUCH_MACHINE "org.freedesktop.machine1.NoSuchMachine"
+#define BUS_ERROR_NO_SUCH_IMAGE "org.freedesktop.machine1.NoSuchImage"
+#define BUS_ERROR_NO_MACHINE_FOR_PID "org.freedesktop.machine1.NoMachineForPID"
+#define BUS_ERROR_MACHINE_EXISTS "org.freedesktop.machine1.MachineExists"
+#define BUS_ERROR_NO_PRIVATE_NETWORKING "org.freedesktop.machine1.NoPrivateNetworking"
+#define BUS_ERROR_NO_SUCH_USER_MAPPING "org.freedesktop.machine1.NoSuchUserMapping"
+#define BUS_ERROR_NO_SUCH_GROUP_MAPPING "org.freedesktop.machine1.NoSuchGroupMapping"
+
+#define BUS_ERROR_NO_SUCH_PORTABLE_IMAGE "org.freedesktop.portable1.NoSuchImage"
+#define BUS_ERROR_BAD_PORTABLE_IMAGE_TYPE "org.freedesktop.portable1.BadImageType"
+
+#define BUS_ERROR_NO_SUCH_SESSION "org.freedesktop.login1.NoSuchSession"
+#define BUS_ERROR_NO_SESSION_FOR_PID "org.freedesktop.login1.NoSessionForPID"
+#define BUS_ERROR_NO_SUCH_USER "org.freedesktop.login1.NoSuchUser"
+#define BUS_ERROR_NO_USER_FOR_PID "org.freedesktop.login1.NoUserForPID"
+#define BUS_ERROR_NO_SUCH_SEAT "org.freedesktop.login1.NoSuchSeat"
+#define BUS_ERROR_SESSION_NOT_ON_SEAT "org.freedesktop.login1.SessionNotOnSeat"
+#define BUS_ERROR_NOT_IN_CONTROL "org.freedesktop.login1.NotInControl"
+#define BUS_ERROR_DEVICE_IS_TAKEN "org.freedesktop.login1.DeviceIsTaken"
+#define BUS_ERROR_DEVICE_NOT_TAKEN "org.freedesktop.login1.DeviceNotTaken"
+#define BUS_ERROR_OPERATION_IN_PROGRESS "org.freedesktop.login1.OperationInProgress"
+#define BUS_ERROR_SLEEP_VERB_NOT_SUPPORTED "org.freedesktop.login1.SleepVerbNotSupported"
+#define BUS_ERROR_SESSION_BUSY "org.freedesktop.login1.SessionBusy"
+#define BUS_ERROR_NOT_YOUR_DEVICE "org.freedesktop.login1.NotYourDevice"
+
+#define BUS_ERROR_AUTOMATIC_TIME_SYNC_ENABLED "org.freedesktop.timedate1.AutomaticTimeSyncEnabled"
+#define BUS_ERROR_NO_NTP_SUPPORT "org.freedesktop.timedate1.NoNTPSupport"
+
+#define BUS_ERROR_NO_SUCH_PROCESS "org.freedesktop.systemd1.NoSuchProcess"
+
+#define BUS_ERROR_NO_NAME_SERVERS "org.freedesktop.resolve1.NoNameServers"
+#define BUS_ERROR_INVALID_REPLY "org.freedesktop.resolve1.InvalidReply"
+#define BUS_ERROR_NO_SUCH_RR "org.freedesktop.resolve1.NoSuchRR"
+#define BUS_ERROR_CNAME_LOOP "org.freedesktop.resolve1.CNameLoop"
+#define BUS_ERROR_ABORTED "org.freedesktop.resolve1.Aborted"
+#define BUS_ERROR_NO_SUCH_SERVICE "org.freedesktop.resolve1.NoSuchService"
+#define BUS_ERROR_DNSSEC_FAILED "org.freedesktop.resolve1.DnssecFailed"
+#define BUS_ERROR_NO_TRUST_ANCHOR "org.freedesktop.resolve1.NoTrustAnchor"
+#define BUS_ERROR_RR_TYPE_UNSUPPORTED "org.freedesktop.resolve1.ResourceRecordTypeUnsupported"
+#define BUS_ERROR_NO_SUCH_LINK "org.freedesktop.resolve1.NoSuchLink"
+#define BUS_ERROR_LINK_BUSY "org.freedesktop.resolve1.LinkBusy"
+#define BUS_ERROR_NETWORK_DOWN "org.freedesktop.resolve1.NetworkDown"
+#define BUS_ERROR_NO_SUCH_DNSSD_SERVICE "org.freedesktop.resolve1.NoSuchDnssdService"
+#define BUS_ERROR_DNSSD_SERVICE_EXISTS "org.freedesktop.resolve1.DnssdServiceExists"
+#define _BUS_ERROR_DNS "org.freedesktop.resolve1.DnsError."
+
+#define BUS_ERROR_NO_SUCH_TRANSFER "org.freedesktop.import1.NoSuchTransfer"
+#define BUS_ERROR_TRANSFER_IN_PROGRESS "org.freedesktop.import1.TransferInProgress"
+
+#define BUS_ERROR_NO_PRODUCT_UUID "org.freedesktop.hostname1.NoProductUUID"
+
+#define BUS_ERROR_SPEED_METER_INACTIVE "org.freedesktop.network1.SpeedMeterInactive"
+#define BUS_ERROR_UNMANAGED_INTERFACE "org.freedesktop.network1.UnmanagedInterface"
+
+#define BUS_ERROR_NO_SUCH_HOME "org.freedesktop.home1.NoSuchHome"
+#define BUS_ERROR_UID_IN_USE "org.freedesktop.home1.UIDInUse"
+#define BUS_ERROR_USER_NAME_EXISTS "org.freedesktop.home1.UserNameExists"
+#define BUS_ERROR_HOME_EXISTS "org.freedesktop.home1.HomeExists"
+#define BUS_ERROR_HOME_ALREADY_ACTIVE "org.freedesktop.home1.HomeAlreadyActive"
+#define BUS_ERROR_HOME_ALREADY_FIXATED "org.freedesktop.home1.HomeAlreadyFixated"
+#define BUS_ERROR_HOME_UNFIXATED "org.freedesktop.home1.HomeUnfixated"
+#define BUS_ERROR_HOME_NOT_ACTIVE "org.freedesktop.home1.HomeNotActive"
+#define BUS_ERROR_HOME_ABSENT "org.freedesktop.home1.HomeAbsent"
+#define BUS_ERROR_HOME_BUSY "org.freedesktop.home1.HomeBusy"
+#define BUS_ERROR_BAD_PASSWORD "org.freedesktop.home1.BadPassword"
+#define BUS_ERROR_BAD_RECOVERY_KEY "org.freedesktop.home1.BadRecoveryKey"
+#define BUS_ERROR_LOW_PASSWORD_QUALITY "org.freedesktop.home1.LowPasswordQuality"
+#define BUS_ERROR_BAD_PASSWORD_AND_NO_TOKEN "org.freedesktop.home1.BadPasswordAndNoToken"
+#define BUS_ERROR_TOKEN_PIN_NEEDED "org.freedesktop.home1.TokenPinNeeded"
+#define BUS_ERROR_TOKEN_PROTECTED_AUTHENTICATION_PATH_NEEDED "org.freedesktop.home1.TokenProtectedAuthenticationPathNeeded"
+#define BUS_ERROR_TOKEN_USER_PRESENCE_NEEDED "org.freedesktop.home1.TokenUserPresenceNeeded"
+#define BUS_ERROR_TOKEN_ACTION_TIMEOUT "org.freedesktop.home1.TokenActionTimeout"
+#define BUS_ERROR_TOKEN_PIN_LOCKED "org.freedesktop.home1.TokenPinLocked"
+#define BUS_ERROR_TOKEN_BAD_PIN "org.freedesktop.home1.BadPin"
+#define BUS_ERROR_TOKEN_BAD_PIN_FEW_TRIES_LEFT "org.freedesktop.home1.BadPinFewTriesLeft"
+#define BUS_ERROR_TOKEN_BAD_PIN_ONE_TRY_LEFT "org.freedesktop.home1.BadPinOneTryLeft"
+#define BUS_ERROR_BAD_SIGNATURE "org.freedesktop.home1.BadSignature"
+#define BUS_ERROR_HOME_RECORD_MISMATCH "org.freedesktop.home1.RecordMismatch"
+#define BUS_ERROR_HOME_RECORD_DOWNGRADE "org.freedesktop.home1.RecordDowngrade"
+#define BUS_ERROR_HOME_RECORD_SIGNED "org.freedesktop.home1.RecordSigned"
+#define BUS_ERROR_BAD_HOME_SIZE "org.freedesktop.home1.BadHomeSize"
+#define BUS_ERROR_NO_PRIVATE_KEY "org.freedesktop.home1.NoPrivateKey"
+#define BUS_ERROR_HOME_LOCKED "org.freedesktop.home1.HomeLocked"
+#define BUS_ERROR_HOME_NOT_LOCKED "org.freedesktop.home1.HomeNotLocked"
+#define BUS_ERROR_NO_DISK_SPACE "org.freedesktop.home1.NoDiskSpace"
+#define BUS_ERROR_TOO_MANY_OPERATIONS "org.freedesktop.home1.TooManyOperations"
+#define BUS_ERROR_AUTHENTICATION_LIMIT_HIT "org.freedesktop.home1.AuthenticationLimitHit"
+#define BUS_ERROR_HOME_CANT_AUTHENTICATE "org.freedesktop.home1.HomeCantAuthenticate"
+
+BUS_ERROR_MAP_ELF_USE(bus_common_errors);
diff --git a/src/libsystemd/sd-bus/bus-container.c b/src/libsystemd/sd-bus/bus-container.c
new file mode 100644
index 0000000..b11ebb3
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-container.c
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "bus-container.h"
+#include "bus-internal.h"
+#include "bus-socket.h"
+#include "fd-util.h"
+#include "namespace-util.h"
+#include "process-util.h"
+#include "string-util.h"
+#include "util.h"
+
+int bus_container_connect_socket(sd_bus *b) {
+        _cleanup_close_pair_ int pair[2] = { -1, -1 };
+        _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
+        int r, error_buf = 0;
+        pid_t child;
+        ssize_t n;
+
+        assert(b);
+        assert(b->input_fd < 0);
+        assert(b->output_fd < 0);
+        assert(b->nspid > 0 || b->machine);
+
+        if (b->nspid <= 0) {
+                log_debug("sd-bus: connecting bus%s%s to machine %s...",
+                          b->description ? " " : "", strempty(b->description), b->machine);
+
+                r = container_get_leader(b->machine, &b->nspid);
+                if (r < 0)
+                        return r;
+        } else
+                log_debug("sd-bus: connecting bus%s%s to namespace of PID "PID_FMT"...",
+                          b->description ? " " : "", strempty(b->description), b->nspid);
+
+        r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
+        if (r < 0)
+                return r;
+
+        b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (b->input_fd < 0)
+                return -errno;
+
+        b->input_fd = fd_move_above_stdio(b->input_fd);
+
+        b->output_fd = b->input_fd;
+
+        bus_socket_setup(b);
+
+        if (socketpair(AF_UNIX, SOCK_SEQPACKET|SOCK_CLOEXEC, 0, pair) < 0)
+                return -errno;
+
+        r = namespace_fork("(sd-buscntrns)", "(sd-buscntr)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
+                           pidnsfd, mntnsfd, -1, usernsfd, rootfd, &child);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                pair[0] = safe_close(pair[0]);
+
+                r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
+                if (r < 0) {
+                        /* Try to send error up */
+                        error_buf = errno;
+                        (void) write(pair[1], &error_buf, sizeof(error_buf));
+                        _exit(EXIT_FAILURE);
+                }
+
+                _exit(EXIT_SUCCESS);
+        }
+
+        pair[1] = safe_close(pair[1]);
+
+        r = wait_for_terminate_and_check("(sd-buscntrns)", child, 0);
+        if (r < 0)
+                return r;
+        if (r != EXIT_SUCCESS)
+                return -EPROTO;
+
+        n = read(pair[0], &error_buf, sizeof(error_buf));
+        if (n < 0)
+                return -errno;
+
+        if (n > 0) {
+                if (n != sizeof(error_buf))
+                        return -EIO;
+
+                if (error_buf < 0)
+                        return -EIO;
+
+                if (error_buf == EINPROGRESS)
+                        return 1;
+
+                if (error_buf > 0)
+                        return -error_buf;
+        }
+
+        return bus_socket_start_auth(b);
+}
diff --git a/src/libsystemd/sd-bus/bus-container.h b/src/libsystemd/sd-bus/bus-container.h
new file mode 100644
index 0000000..cb503a5
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-container.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+int bus_container_connect_socket(sd_bus *b);
diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
new file mode 100644
index 0000000..3ee22c9
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -0,0 +1,942 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#if HAVE_VALGRIND_MEMCHECK_H
+#include <valgrind/memcheck.h>
+#endif
+
+#include <errno.h>
+#include <stddef.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-control.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "capability-util.h"
+#include "process-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+
+_public_ int sd_bus_get_unique_name(sd_bus *bus, const char **unique) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(unique, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        *unique = bus->unique_name;
+        return 0;
+}
+
+static int validate_request_name_parameters(
+                sd_bus *bus,
+                const char *name,
+                uint64_t flags,
+                uint32_t *ret_param) {
+
+        uint32_t param = 0;
+
+        assert(bus);
+        assert(name);
+        assert(ret_param);
+
+        assert_return(!(flags & ~(SD_BUS_NAME_ALLOW_REPLACEMENT|SD_BUS_NAME_REPLACE_EXISTING|SD_BUS_NAME_QUEUE)), -EINVAL);
+        assert_return(service_name_is_valid(name), -EINVAL);
+        assert_return(name[0] != ':', -EINVAL);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        /* Don't allow requesting the special driver and local names */
+        if (STR_IN_SET(name, "org.freedesktop.DBus", "org.freedesktop.DBus.Local"))
+                return -EINVAL;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (flags & SD_BUS_NAME_ALLOW_REPLACEMENT)
+                param |= BUS_NAME_ALLOW_REPLACEMENT;
+        if (flags & SD_BUS_NAME_REPLACE_EXISTING)
+                param |= BUS_NAME_REPLACE_EXISTING;
+        if (!(flags & SD_BUS_NAME_QUEUE))
+                param |= BUS_NAME_DO_NOT_QUEUE;
+
+        *ret_param = param;
+
+        return 0;
+}
+
+_public_ int sd_bus_request_name(
+                sd_bus *bus,
+                const char *name,
+                uint64_t flags) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        uint32_t ret, param = 0;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(name, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = validate_request_name_parameters(bus, name, flags, &param);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "RequestName",
+                        NULL,
+                        &reply,
+                        "su",
+                        name,
+                        param);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "u", &ret);
+        if (r < 0)
+                return r;
+
+        switch (ret) {
+
+        case BUS_NAME_ALREADY_OWNER:
+                return -EALREADY;
+
+        case BUS_NAME_EXISTS:
+                return -EEXIST;
+
+        case BUS_NAME_IN_QUEUE:
+                return 0;
+
+        case BUS_NAME_PRIMARY_OWNER:
+                return 1;
+        }
+
+        return -EIO;
+}
+
+static int default_request_name_handler(
+                sd_bus_message *m,
+                void *userdata,
+                sd_bus_error *ret_error) {
+
+        uint32_t ret;
+        int r;
+
+        assert(m);
+
+        if (sd_bus_message_is_method_error(m, NULL)) {
+                log_debug_errno(sd_bus_message_get_errno(m),
+                                "Unable to request name, failing connection: %s",
+                                sd_bus_message_get_error(m)->message);
+
+                bus_enter_closing(sd_bus_message_get_bus(m));
+                return 1;
+        }
+
+        r = sd_bus_message_read(m, "u", &ret);
+        if (r < 0)
+                return r;
+
+        switch (ret) {
+
+        case BUS_NAME_ALREADY_OWNER:
+                log_debug("Already owner of requested service name, ignoring.");
+                return 1;
+
+        case BUS_NAME_IN_QUEUE:
+                log_debug("In queue for requested service name.");
+                return 1;
+
+        case BUS_NAME_PRIMARY_OWNER:
+                log_debug("Successfully acquired requested service name.");
+                return 1;
+
+        case BUS_NAME_EXISTS:
+                log_debug("Requested service name already owned, failing connection.");
+                bus_enter_closing(sd_bus_message_get_bus(m));
+                return 1;
+        }
+
+        log_debug("Unexpected response from RequestName(), failing connection.");
+        bus_enter_closing(sd_bus_message_get_bus(m));
+        return 1;
+}
+
+_public_ int sd_bus_request_name_async(
+                sd_bus *bus,
+                sd_bus_slot **ret_slot,
+                const char *name,
+                uint64_t flags,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        uint32_t param = 0;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(name, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = validate_request_name_parameters(bus, name, flags, &param);
+        if (r < 0)
+                return r;
+
+        return sd_bus_call_method_async(
+                        bus,
+                        ret_slot,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "RequestName",
+                        callback ?: default_request_name_handler,
+                        userdata,
+                        "su",
+                        name,
+                        param);
+}
+
+static int validate_release_name_parameters(
+                sd_bus *bus,
+                const char *name) {
+
+        assert(bus);
+        assert(name);
+
+        assert_return(service_name_is_valid(name), -EINVAL);
+        assert_return(name[0] != ':', -EINVAL);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        /* Don't allow releasing the special driver and local names */
+        if (STR_IN_SET(name, "org.freedesktop.DBus", "org.freedesktop.DBus.Local"))
+                return -EINVAL;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        return 0;
+}
+
+_public_ int sd_bus_release_name(
+                sd_bus *bus,
+                const char *name) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        uint32_t ret;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(name, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = validate_release_name_parameters(bus, name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "ReleaseName",
+                        NULL,
+                        &reply,
+                        "s",
+                        name);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "u", &ret);
+        if (r < 0)
+                return r;
+
+        switch (ret) {
+
+        case BUS_NAME_NON_EXISTENT:
+                return -ESRCH;
+
+        case BUS_NAME_NOT_OWNER:
+                return -EADDRINUSE;
+
+        case BUS_NAME_RELEASED:
+                return 0;
+        }
+
+        return -EIO;
+}
+
+static int default_release_name_handler(
+                sd_bus_message *m,
+                void *userdata,
+                sd_bus_error *ret_error) {
+
+        uint32_t ret;
+        int r;
+
+        assert(m);
+
+        if (sd_bus_message_is_method_error(m, NULL)) {
+                log_debug_errno(sd_bus_message_get_errno(m),
+                                "Unable to release name, failing connection: %s",
+                                sd_bus_message_get_error(m)->message);
+
+                bus_enter_closing(sd_bus_message_get_bus(m));
+                return 1;
+        }
+
+        r = sd_bus_message_read(m, "u", &ret);
+        if (r < 0)
+                return r;
+
+        switch (ret) {
+
+        case BUS_NAME_NON_EXISTENT:
+                log_debug("Name asked to release is not taken currently, ignoring.");
+                return 1;
+
+        case BUS_NAME_NOT_OWNER:
+                log_debug("Name asked to release is owned by somebody else, ignoring.");
+                return 1;
+
+        case BUS_NAME_RELEASED:
+                log_debug("Name successfully released.");
+                return 1;
+        }
+
+        log_debug("Unexpected response from ReleaseName(), failing connection.");
+        bus_enter_closing(sd_bus_message_get_bus(m));
+        return 1;
+}
+
+_public_ int sd_bus_release_name_async(
+                sd_bus *bus,
+                sd_bus_slot **ret_slot,
+                const char *name,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(name, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = validate_release_name_parameters(bus, name);
+        if (r < 0)
+                return r;
+
+        return sd_bus_call_method_async(
+                        bus,
+                        ret_slot,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "ReleaseName",
+                        callback ?: default_release_name_handler,
+                        userdata,
+                        "s",
+                        name);
+}
+
+_public_ int sd_bus_list_names(sd_bus *bus, char ***acquired, char ***activatable) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_strv_free_ char **x = NULL, **y = NULL;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(acquired || activatable, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (acquired) {
+                r = sd_bus_call_method(
+                                bus,
+                                "org.freedesktop.DBus",
+                                "/org/freedesktop/DBus",
+                                "org.freedesktop.DBus",
+                                "ListNames",
+                                NULL,
+                                &reply,
+                                NULL);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_read_strv(reply, &x);
+                if (r < 0)
+                        return r;
+
+                reply = sd_bus_message_unref(reply);
+        }
+
+        if (activatable) {
+                r = sd_bus_call_method(
+                                bus,
+                                "org.freedesktop.DBus",
+                                "/org/freedesktop/DBus",
+                                "org.freedesktop.DBus",
+                                "ListActivatableNames",
+                                NULL,
+                                &reply,
+                                NULL);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_read_strv(reply, &y);
+                if (r < 0)
+                        return r;
+
+                *activatable = TAKE_PTR(y);
+        }
+
+        if (acquired)
+                *acquired = TAKE_PTR(x);
+
+        return 0;
+}
+
+_public_ int sd_bus_get_name_creds(
+                sd_bus *bus,
+                const char *name,
+                uint64_t mask,
+                sd_bus_creds **creds) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply_unique = NULL, *reply = NULL;
+        _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *c = NULL;
+        const char *unique;
+        pid_t pid = 0;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(name, -EINVAL);
+        assert_return((mask & ~SD_BUS_CREDS_AUGMENT) <= _SD_BUS_CREDS_ALL, -EOPNOTSUPP);
+        assert_return(mask == 0 || creds, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(service_name_is_valid(name), -EINVAL);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        /* Turn off augmenting if this isn't a local connection. If the connection is not local, then /proc is not
+         * going to match. */
+        if (!bus->is_local)
+                mask &= ~SD_BUS_CREDS_AUGMENT;
+
+        if (streq(name, "org.freedesktop.DBus.Local"))
+                return -EINVAL;
+
+        if (streq(name, "org.freedesktop.DBus"))
+                return sd_bus_get_owner_creds(bus, mask, creds);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* If the name is unique anyway, we can use it directly */
+        unique = name[0] == ':' ? name : NULL;
+
+        /* Only query the owner if the caller wants to know it and the name is not unique anyway, or if the caller just
+         * wants to check whether a name exists */
+        if ((FLAGS_SET(mask, SD_BUS_CREDS_UNIQUE_NAME) && !unique) || mask == 0) {
+                r = sd_bus_call_method(
+                                bus,
+                                "org.freedesktop.DBus",
+                                "/org/freedesktop/DBus",
+                                "org.freedesktop.DBus",
+                                "GetNameOwner",
+                                NULL,
+                                &reply_unique,
+                                "s",
+                                name);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_read(reply_unique, "s", &unique);
+                if (r < 0)
+                        return r;
+        }
+
+        if (mask != 0) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                bool need_pid, need_uid, need_selinux, need_separate_calls;
+
+                c = bus_creds_new();
+                if (!c)
+                        return -ENOMEM;
+
+                if ((mask & SD_BUS_CREDS_UNIQUE_NAME) && unique) {
+                        c->unique_name = strdup(unique);
+                        if (!c->unique_name)
+                                return -ENOMEM;
+
+                        c->mask |= SD_BUS_CREDS_UNIQUE_NAME;
+                }
+
+                need_pid = (mask & SD_BUS_CREDS_PID) ||
+                        ((mask & SD_BUS_CREDS_AUGMENT) &&
+                         (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+                                  SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
+                                  SD_BUS_CREDS_SUPPLEMENTARY_GIDS|
+                                  SD_BUS_CREDS_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
+                                  SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID|
+                                  SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
+                                  SD_BUS_CREDS_SELINUX_CONTEXT|
+                                  SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID)));
+                need_uid = mask & SD_BUS_CREDS_EUID;
+                need_selinux = mask & SD_BUS_CREDS_SELINUX_CONTEXT;
+
+                if (need_pid + need_uid + need_selinux > 1) {
+
+                        /* If we need more than one of the credentials, then use GetConnectionCredentials() */
+
+                        r = sd_bus_call_method(
+                                        bus,
+                                        "org.freedesktop.DBus",
+                                        "/org/freedesktop/DBus",
+                                        "org.freedesktop.DBus",
+                                        "GetConnectionCredentials",
+                                        &error,
+                                        &reply,
+                                        "s",
+                                        unique ?: name);
+
+                        if (r < 0) {
+
+                                if (!sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD))
+                                        return r;
+
+                                /* If we got an unknown method error, fall back to the individual calls... */
+                                need_separate_calls = true;
+                                sd_bus_error_free(&error);
+
+                        } else {
+                                need_separate_calls = false;
+
+                                r = sd_bus_message_enter_container(reply, 'a', "{sv}");
+                                if (r < 0)
+                                        return r;
+
+                                for (;;) {
+                                        const char *m;
+
+                                        r = sd_bus_message_enter_container(reply, 'e', "sv");
+                                        if (r < 0)
+                                                return r;
+                                        if (r == 0)
+                                                break;
+
+                                        r = sd_bus_message_read(reply, "s", &m);
+                                        if (r < 0)
+                                                return r;
+
+                                        if (need_uid && streq(m, "UnixUserID")) {
+                                                uint32_t u;
+
+                                                r = sd_bus_message_read(reply, "v", "u", &u);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->euid = u;
+                                                c->mask |= SD_BUS_CREDS_EUID;
+
+                                        } else if (need_pid && streq(m, "ProcessID")) {
+                                                uint32_t p;
+
+                                                r = sd_bus_message_read(reply, "v", "u", &p);
+                                                if (r < 0)
+                                                        return r;
+
+                                                pid = p;
+                                                if (mask & SD_BUS_CREDS_PID) {
+                                                        c->pid = p;
+                                                        c->mask |= SD_BUS_CREDS_PID;
+                                                }
+
+                                        } else if (need_selinux && streq(m, "LinuxSecurityLabel")) {
+                                                const void *p = NULL;
+                                                size_t sz = 0;
+
+                                                r = sd_bus_message_enter_container(reply, 'v', "ay");
+                                                if (r < 0)
+                                                        return r;
+
+                                                r = sd_bus_message_read_array(reply, 'y', &p, &sz);
+                                                if (r < 0)
+                                                        return r;
+
+                                                free(c->label);
+                                                c->label = strndup(p, sz);
+                                                if (!c->label)
+                                                        return -ENOMEM;
+
+                                                c->mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+
+                                                r = sd_bus_message_exit_container(reply);
+                                                if (r < 0)
+                                                        return r;
+                                        } else {
+                                                r = sd_bus_message_skip(reply, "v");
+                                                if (r < 0)
+                                                        return r;
+                                        }
+
+                                        r = sd_bus_message_exit_container(reply);
+                                        if (r < 0)
+                                                return r;
+                                }
+
+                                r = sd_bus_message_exit_container(reply);
+                                if (r < 0)
+                                        return r;
+
+                                if (need_pid && pid == 0)
+                                        return -EPROTO;
+                        }
+
+                } else /* When we only need a single field, then let's use separate calls */
+                        need_separate_calls = true;
+
+                if (need_separate_calls) {
+                        if (need_pid) {
+                                uint32_t u;
+
+                                r = sd_bus_call_method(
+                                                bus,
+                                                "org.freedesktop.DBus",
+                                                "/org/freedesktop/DBus",
+                                                "org.freedesktop.DBus",
+                                                "GetConnectionUnixProcessID",
+                                                NULL,
+                                                &reply,
+                                                "s",
+                                                unique ?: name);
+                                if (r < 0)
+                                        return r;
+
+                                r = sd_bus_message_read(reply, "u", &u);
+                                if (r < 0)
+                                        return r;
+
+                                pid = u;
+                                if (mask & SD_BUS_CREDS_PID) {
+                                        c->pid = u;
+                                        c->mask |= SD_BUS_CREDS_PID;
+                                }
+
+                                reply = sd_bus_message_unref(reply);
+                        }
+
+                        if (need_uid) {
+                                uint32_t u;
+
+                                r = sd_bus_call_method(
+                                                bus,
+                                                "org.freedesktop.DBus",
+                                                "/org/freedesktop/DBus",
+                                                "org.freedesktop.DBus",
+                                                "GetConnectionUnixUser",
+                                                NULL,
+                                                &reply,
+                                                "s",
+                                                unique ?: name);
+                                if (r < 0)
+                                        return r;
+
+                                r = sd_bus_message_read(reply, "u", &u);
+                                if (r < 0)
+                                        return r;
+
+                                c->euid = u;
+                                c->mask |= SD_BUS_CREDS_EUID;
+
+                                reply = sd_bus_message_unref(reply);
+                        }
+
+                        if (need_selinux) {
+                                const void *p = NULL;
+                                size_t sz = 0;
+
+                                r = sd_bus_call_method(
+                                                bus,
+                                                "org.freedesktop.DBus",
+                                                "/org/freedesktop/DBus",
+                                                "org.freedesktop.DBus",
+                                                "GetConnectionSELinuxSecurityContext",
+                                                &error,
+                                                &reply,
+                                                "s",
+                                                unique ?: name);
+                                if (r < 0) {
+                                        if (!sd_bus_error_has_name(&error, "org.freedesktop.DBus.Error.SELinuxSecurityContextUnknown"))
+                                                return r;
+
+                                        /* no data is fine */
+                                } else {
+                                        r = sd_bus_message_read_array(reply, 'y', &p, &sz);
+                                        if (r < 0)
+                                                return r;
+
+                                        c->label = memdup_suffix0(p, sz);
+                                        if (!c->label)
+                                                return -ENOMEM;
+
+                                        c->mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+                                }
+                        }
+                }
+
+                r = bus_creds_add_more(c, mask, pid, 0);
+                if (r < 0 && r != -ESRCH) /* Return the error, but ignore ESRCH which just means the process is already gone */
+                        return r;
+        }
+
+        if (creds)
+                *creds = TAKE_PTR(c);
+
+        return 0;
+}
+
+_public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **ret) {
+        _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *c = NULL;
+        bool do_label, do_groups;
+        pid_t pid = 0;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return((mask & ~SD_BUS_CREDS_AUGMENT) <= _SD_BUS_CREDS_ALL, -EOPNOTSUPP);
+        assert_return(ret, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (!bus->is_local)
+                mask &= ~SD_BUS_CREDS_AUGMENT;
+
+        do_label = bus->label && (mask & SD_BUS_CREDS_SELINUX_CONTEXT);
+        do_groups = bus->n_groups != (size_t) -1 && (mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS);
+
+        /* Avoid allocating anything if we have no chance of returning useful data */
+        if (!bus->ucred_valid && !do_label && !do_groups)
+                return -ENODATA;
+
+        c = bus_creds_new();
+        if (!c)
+                return -ENOMEM;
+
+        if (bus->ucred_valid) {
+                if (pid_is_valid(bus->ucred.pid)) {
+                        pid = c->pid = bus->ucred.pid;
+                        c->mask |= SD_BUS_CREDS_PID & mask;
+                }
+
+                if (uid_is_valid(bus->ucred.uid)) {
+                        c->euid = bus->ucred.uid;
+                        c->mask |= SD_BUS_CREDS_EUID & mask;
+                }
+
+                if (gid_is_valid(bus->ucred.gid)) {
+                        c->egid = bus->ucred.gid;
+                        c->mask |= SD_BUS_CREDS_EGID & mask;
+                }
+        }
+
+        if (do_label) {
+                c->label = strdup(bus->label);
+                if (!c->label)
+                        return -ENOMEM;
+
+                c->mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+        }
+
+        if (do_groups) {
+                c->supplementary_gids = newdup(gid_t, bus->groups, bus->n_groups);
+                if (!c->supplementary_gids)
+                        return -ENOMEM;
+
+                c->n_supplementary_gids = bus->n_groups;
+
+                c->mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
+        }
+
+        r = bus_creds_add_more(c, mask, pid, 0);
+        if (r < 0 && r != -ESRCH) /* If the process vanished, then don't complain, just return what we got */
+                return r;
+
+        *ret = TAKE_PTR(c);
+
+        return 0;
+}
+
+#define append_eavesdrop(bus, m)                                        \
+        ((bus)->is_monitor                                              \
+         ? (isempty(m) ? "eavesdrop='true'" : strjoina((m), ",eavesdrop='true'")) \
+         : (m))
+
+int bus_add_match_internal(
+                sd_bus *bus,
+                const char *match,
+                uint64_t *ret_counter) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        const char *e;
+        int r;
+
+        assert(bus);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        e = append_eavesdrop(bus, match);
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "AddMatch",
+                        NULL,
+                        &reply,
+                        "s",
+                        e);
+        if (r < 0)
+                return r;
+
+        /* If the caller asked for it, return the read counter of the reply */
+        if (ret_counter)
+                *ret_counter = reply->read_counter;
+
+        return r;
+}
+
+int bus_add_match_internal_async(
+                sd_bus *bus,
+                sd_bus_slot **ret_slot,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        const char *e;
+
+        assert(bus);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        e = append_eavesdrop(bus, match);
+
+        return sd_bus_call_method_async(
+                        bus,
+                        ret_slot,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "AddMatch",
+                        callback,
+                        userdata,
+                        "s",
+                        e);
+}
+
+int bus_remove_match_internal(
+                sd_bus *bus,
+                const char *match) {
+
+        const char *e;
+
+        assert(bus);
+        assert(match);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        e = append_eavesdrop(bus, match);
+
+        /* Fire and forget */
+
+        return sd_bus_call_method_async(
+                        bus,
+                        NULL,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "RemoveMatch",
+                        NULL,
+                        NULL,
+                        "s",
+                        e);
+}
+
+_public_ int sd_bus_get_name_machine_id(sd_bus *bus, const char *name, sd_id128_t *machine) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL, *m = NULL;
+        const char *mid;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(name, -EINVAL);
+        assert_return(machine, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(service_name_is_valid(name), -EINVAL);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (streq_ptr(name, bus->unique_name))
+                return sd_id128_get_machine(machine);
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        name,
+                        "/",
+                        "org.freedesktop.DBus.Peer",
+                        "GetMachineId");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_set_auto_start(m, false);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_call(bus, m, 0, NULL, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read(reply, "s", &mid);
+        if (r < 0)
+                return r;
+
+        return sd_id128_from_string(mid, machine);
+}
diff --git a/src/libsystemd/sd-bus/bus-control.h b/src/libsystemd/sd-bus/bus-control.h
new file mode 100644
index 0000000..8182b9c
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-control.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+int bus_add_match_internal(sd_bus *bus, const char *match, uint64_t *ret_counter);
+int bus_add_match_internal_async(sd_bus *bus, sd_bus_slot **ret, const char *match, sd_bus_message_handler_t callback, void *userdata);
+
+int bus_remove_match_internal(sd_bus *bus, const char *match);
diff --git a/src/libsystemd/sd-bus/bus-convenience.c b/src/libsystemd/sd-bus/bus-convenience.c
new file mode 100644
index 0000000..0314642
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-convenience.c
@@ -0,0 +1,788 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-signature.h"
+#include "bus-type.h"
+#include "bus-util.h"
+#include "string-util.h"
+
+_public_ int sd_bus_emit_signalv(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *member,
+                const char *types, va_list ap) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        r = sd_bus_message_new_signal(bus, &m, path, interface, member);
+        if (r < 0)
+                return r;
+
+        if (!isempty(types)) {
+                r = sd_bus_message_appendv(m, types, ap);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+_public_ int sd_bus_emit_signal(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *member,
+                const char *types, ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_emit_signalv(bus, path, interface, member, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_call_method_asyncv(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_message_handler_t callback,
+                void *userdata,
+                const char *types, va_list ap) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        r = sd_bus_message_new_method_call(bus, &m, destination, path, interface, member);
+        if (r < 0)
+                return r;
+
+        if (!isempty(types)) {
+                r = sd_bus_message_appendv(m, types, ap);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_call_async(bus, slot, m, callback, userdata, 0);
+}
+
+_public_ int sd_bus_call_method_async(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_message_handler_t callback,
+                void *userdata,
+                const char *types, ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_call_method_asyncv(bus, slot, destination, path, interface, member, callback, userdata, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_call_methodv(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                sd_bus_message **reply,
+                const char *types, va_list ap) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        bus_assert_return(bus, -EINVAL, error);
+        bus_assert_return(bus = bus_resolve(bus), -ENOPKG, error);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = sd_bus_message_new_method_call(bus, &m, destination, path, interface, member);
+        if (r < 0)
+                goto fail;
+
+        if (!isempty(types)) {
+                r = sd_bus_message_appendv(m, types, ap);
+                if (r < 0)
+                        goto fail;
+        }
+
+        return sd_bus_call(bus, m, 0, error, reply);
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_call_method(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                sd_bus_message **reply,
+                const char *types, ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_call_methodv(bus, destination, path, interface, member, error, reply, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_reply_method_returnv(
+                sd_bus_message *call,
+                const char *types, va_list ap) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        r = sd_bus_message_new_method_return(call, &m);
+        if (r < 0)
+                return r;
+
+        if (!isempty(types)) {
+                r = sd_bus_message_appendv(m, types, ap);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_send(call->bus, m, NULL);
+}
+
+_public_ int sd_bus_reply_method_return(
+                sd_bus_message *call,
+                const char *types, ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_reply_method_returnv(call, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_reply_method_error(
+                sd_bus_message *call,
+                const sd_bus_error *e) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(sd_bus_error_is_set(e), -EINVAL);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        r = sd_bus_message_new_method_error(call, &m, e);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send(call->bus, m, NULL);
+}
+
+_public_ int sd_bus_reply_method_errorfv(
+                sd_bus_message *call,
+                const char *name,
+                const char *format,
+                va_list ap) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        bus_error_setfv(&error, name, format, ap);
+
+        return sd_bus_reply_method_error(call, &error);
+}
+
+_public_ int sd_bus_reply_method_errorf(
+                sd_bus_message *call,
+                const char *name,
+                const char *format,
+                ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, format);
+        r = sd_bus_reply_method_errorfv(call, name, format, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_reply_method_errno(
+                sd_bus_message *call,
+                int error,
+                const sd_bus_error *p) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        if (sd_bus_error_is_set(p))
+                return sd_bus_reply_method_error(call, p);
+
+        sd_bus_error_set_errno(&berror, error);
+
+        return sd_bus_reply_method_error(call, &berror);
+}
+
+_public_ int sd_bus_reply_method_errnofv(
+                sd_bus_message *call,
+                int error,
+                const char *format,
+                va_list ap) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        if (call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 0;
+
+        sd_bus_error_set_errnofv(&berror, error, format, ap);
+
+        return sd_bus_reply_method_error(call, &berror);
+}
+
+_public_ int sd_bus_reply_method_errnof(
+                sd_bus_message *call,
+                int error,
+                const char *format,
+                ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, format);
+        r = sd_bus_reply_method_errnofv(call, error, format, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_get_property(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                sd_bus_message **reply,
+                const char *type) {
+
+        sd_bus_message *rep = NULL;
+        int r;
+
+        bus_assert_return(bus, -EINVAL, error);
+        bus_assert_return(bus = bus_resolve(bus), -ENOPKG, error);
+        bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
+        bus_assert_return(member_name_is_valid(member), -EINVAL, error);
+        bus_assert_return(reply, -EINVAL, error);
+        bus_assert_return(signature_is_single(type, false), -EINVAL, error);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = sd_bus_call_method(bus, destination, path,
+                               "org.freedesktop.DBus.Properties", "Get",
+                               error, &rep,
+                               "ss", strempty(interface), member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_enter_container(rep, 'v', type);
+        if (r < 0) {
+                sd_bus_message_unref(rep);
+                goto fail;
+        }
+
+        *reply = rep;
+        return 0;
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_get_property_trivial(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                char type, void *ptr) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        int r;
+
+        bus_assert_return(bus, -EINVAL, error);
+        bus_assert_return(bus = bus_resolve(bus), -ENOPKG, error);
+        bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
+        bus_assert_return(member_name_is_valid(member), -EINVAL, error);
+        bus_assert_return(bus_type_is_trivial(type), -EINVAL, error);
+        bus_assert_return(ptr, -EINVAL, error);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_enter_container(reply, 'v', CHAR_TO_STR(type));
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_read_basic(reply, type, ptr);
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_get_property_string(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                char **ret) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        const char *s;
+        char *n;
+        int r;
+
+        bus_assert_return(bus, -EINVAL, error);
+        bus_assert_return(bus = bus_resolve(bus), -ENOPKG, error);
+        bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
+        bus_assert_return(member_name_is_valid(member), -EINVAL, error);
+        bus_assert_return(ret, -EINVAL, error);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_enter_container(reply, 'v', "s");
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_read_basic(reply, 's', &s);
+        if (r < 0)
+                goto fail;
+
+        n = strdup(s);
+        if (!n) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        *ret = n;
+        return 0;
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_get_property_strv(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                char ***ret) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        int r;
+
+        bus_assert_return(bus, -EINVAL, error);
+        bus_assert_return(bus = bus_resolve(bus), -ENOPKG, error);
+        bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
+        bus_assert_return(member_name_is_valid(member), -EINVAL, error);
+        bus_assert_return(ret, -EINVAL, error);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = sd_bus_call_method(bus, destination, path, "org.freedesktop.DBus.Properties", "Get", error, &reply, "ss", strempty(interface), member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_enter_container(reply, 'v', NULL);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_read_strv(reply, ret);
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_set_propertyv(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                const char *type, va_list ap) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        bus_assert_return(bus, -EINVAL, error);
+        bus_assert_return(bus = bus_resolve(bus), -ENOPKG, error);
+        bus_assert_return(isempty(interface) || interface_name_is_valid(interface), -EINVAL, error);
+        bus_assert_return(member_name_is_valid(member), -EINVAL, error);
+        bus_assert_return(signature_is_single(type, false), -EINVAL, error);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = sd_bus_message_new_method_call(bus, &m, destination, path, "org.freedesktop.DBus.Properties", "Set");
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_append(m, "ss", strempty(interface), member);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_open_container(m, 'v', type);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_appendv(m, type, ap);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                goto fail;
+
+        return sd_bus_call(bus, m, 0, error, NULL);
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_set_property(
+                sd_bus *bus,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_error *error,
+                const char *type, ...) {
+
+        va_list ap;
+        int r;
+
+        va_start(ap, type);
+        r = sd_bus_set_propertyv(bus, destination, path, interface, member, error, type, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_query_sender_creds(sd_bus_message *call, uint64_t mask, sd_bus_creds **ret) {
+        sd_bus_creds *c;
+        int r;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+        assert_return(ret, -EINVAL);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        c = sd_bus_message_get_creds(call);
+
+        /* All data we need? */
+        if (c && (mask & ~c->mask) == 0) {
+                *ret = sd_bus_creds_ref(c);
+                return 0;
+        }
+
+        /* No data passed? Or not enough data passed to retrieve the missing bits? */
+        if (!c || !(c->mask & SD_BUS_CREDS_PID)) {
+                /* We couldn't read anything from the call, let's try
+                 * to get it from the sender or peer. */
+
+                if (call->sender)
+                        /* There's a sender, but the creds are missing. */
+                        return sd_bus_get_name_creds(call->bus, call->sender, mask, ret);
+                else
+                        /* There's no sender. For direct connections
+                         * the credentials of the AF_UNIX peer matter,
+                         * which may be queried via sd_bus_get_owner_creds(). */
+                        return sd_bus_get_owner_creds(call->bus, mask, ret);
+        }
+
+        r = bus_creds_extend_by_pid(c, mask, ret);
+        if (r == -ESRCH) {
+                /* Process doesn't exist anymore? propagate the few things we have */
+                *ret = sd_bus_creds_ref(c);
+                return 0;
+        }
+
+        return r;
+}
+
+_public_ int sd_bus_query_sender_privilege(sd_bus_message *call, int capability) {
+        _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
+        uid_t our_uid;
+        bool know_caps = false;
+        int r;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->bus, -EINVAL);
+        assert_return(!bus_pid_changed(call->bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(call->bus->state))
+                return -ENOTCONN;
+
+        if (capability >= 0) {
+
+                r = sd_bus_query_sender_creds(call, SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EFFECTIVE_CAPS, &creds);
+                if (r < 0)
+                        return r;
+
+                /* We cannot use augmented caps for authorization,
+                 * since then data is acquired raceful from
+                 * /proc. This can never actually happen, but let's
+                 * better be safe than sorry, and do an extra check
+                 * here. */
+                assert_return((sd_bus_creds_get_augmented_mask(creds) & SD_BUS_CREDS_EFFECTIVE_CAPS) == 0, -EPERM);
+
+                r = sd_bus_creds_has_effective_cap(creds, capability);
+                if (r > 0)
+                        return 1;
+                if (r == 0)
+                        know_caps = true;
+        } else {
+                r = sd_bus_query_sender_creds(call, SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID, &creds);
+                if (r < 0)
+                        return r;
+        }
+
+        /* Now, check the UID, but only if the capability check wasn't
+         * sufficient */
+        our_uid = getuid();
+        if (our_uid != 0 || !know_caps || capability < 0) {
+                uid_t sender_uid;
+
+                /* We cannot use augmented uid/euid for authorization,
+                 * since then data is acquired raceful from
+                 * /proc. This can never actually happen, but let's
+                 * better be safe than sorry, and do an extra check
+                 * here. */
+                assert_return((sd_bus_creds_get_augmented_mask(creds) & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID)) == 0, -EPERM);
+
+                /* Try to use the EUID, if we have it. */
+                r = sd_bus_creds_get_euid(creds, &sender_uid);
+                if (r < 0)
+                        r = sd_bus_creds_get_uid(creds, &sender_uid);
+
+                if (r >= 0) {
+                        /* Sender has same UID as us, then let's grant access */
+                        if (sender_uid == our_uid)
+                                return 1;
+
+                        /* Sender is root, we are not root. */
+                        if (our_uid != 0 && sender_uid == 0)
+                                return 1;
+                }
+        }
+
+        return 0;
+}
+
+#define make_expression(sender, path, interface, member)        \
+        strjoina(                                               \
+                "type='signal'",                                \
+                sender ? ",sender='" : "",                      \
+                sender ?: "",                                   \
+                sender ? "'" : "",                              \
+                path ? ",path='" : "",                          \
+                path ?: "",                                     \
+                path ? "'" : "",                                \
+                interface ? ",interface='" : "",                \
+                interface ?: "",                                \
+                interface ? "'" : "",                           \
+                member ? ",member='" : "",                      \
+                member ?: "",                                   \
+                member ? "'" : ""                               \
+        )
+
+_public_ int sd_bus_match_signal(
+                sd_bus *bus,
+                sd_bus_slot **ret,
+                const char *sender,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        const char *expression;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(!sender || service_name_is_valid(sender), -EINVAL);
+        assert_return(!path || object_path_is_valid(path), -EINVAL);
+        assert_return(!interface || interface_name_is_valid(interface), -EINVAL);
+        assert_return(!member || member_name_is_valid(member), -EINVAL);
+
+        expression = make_expression(sender, path, interface, member);
+
+        return sd_bus_add_match(bus, ret, expression, callback, userdata);
+}
+
+_public_ int sd_bus_match_signal_async(
+                sd_bus *bus,
+                sd_bus_slot **ret,
+                const char *sender,
+                const char *path,
+                const char *interface,
+                const char *member,
+                sd_bus_message_handler_t callback,
+                sd_bus_message_handler_t install_callback,
+                void *userdata) {
+
+        const char *expression;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(!sender || service_name_is_valid(sender), -EINVAL);
+        assert_return(!path || object_path_is_valid(path), -EINVAL);
+        assert_return(!interface || interface_name_is_valid(interface), -EINVAL);
+        assert_return(!member || member_name_is_valid(member), -EINVAL);
+
+        expression = make_expression(sender, path, interface, member);
+
+        return sd_bus_add_match_async(bus, ret, expression, callback, install_callback, userdata);
+}
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
new file mode 100644
index 0000000..3896d94
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -0,0 +1,1340 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <linux/capability.h>
+#include <stdlib.h>
+
+#include "alloc-util.h"
+#include "audit-util.h"
+#include "bus-creds.h"
+#include "bus-label.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "capability-util.h"
+#include "cgroup-util.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "hexdecoct.h"
+#include "parse-util.h"
+#include "process-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "user-util.h"
+#include "util.h"
+
+enum {
+        CAP_OFFSET_INHERITABLE = 0,
+        CAP_OFFSET_PERMITTED = 1,
+        CAP_OFFSET_EFFECTIVE = 2,
+        CAP_OFFSET_BOUNDING = 3
+};
+
+void bus_creds_done(sd_bus_creds *c) {
+        assert(c);
+
+        /* For internal bus cred structures that are allocated by
+         * something else */
+
+        free(c->session);
+        free(c->unit);
+        free(c->user_unit);
+        free(c->slice);
+        free(c->user_slice);
+        free(c->unescaped_description);
+        free(c->supplementary_gids);
+        free(c->tty);
+
+        free(c->well_known_names); /* note that this is an strv, but
+                                    * we only free the array, not the
+                                    * strings the array points to. The
+                                    * full strv we only free if
+                                    * c->allocated is set, see
+                                    * below. */
+
+        strv_free(c->cmdline_array);
+}
+
+_public_ sd_bus_creds *sd_bus_creds_ref(sd_bus_creds *c) {
+
+        if (!c)
+                return NULL;
+
+        if (c->allocated) {
+                assert(c->n_ref > 0);
+                c->n_ref++;
+        } else {
+                sd_bus_message *m;
+
+                /* If this is an embedded creds structure, then
+                 * forward ref counting to the message */
+                m = container_of(c, sd_bus_message, creds);
+                sd_bus_message_ref(m);
+        }
+
+        return c;
+}
+
+_public_ sd_bus_creds *sd_bus_creds_unref(sd_bus_creds *c) {
+
+        if (!c)
+                return NULL;
+
+        if (c->allocated) {
+                assert(c->n_ref > 0);
+                c->n_ref--;
+
+                if (c->n_ref == 0) {
+                        free(c->comm);
+                        free(c->tid_comm);
+                        free(c->exe);
+                        free(c->cmdline);
+                        free(c->cgroup);
+                        free(c->capability);
+                        free(c->label);
+                        free(c->unique_name);
+                        free(c->cgroup_root);
+                        free(c->description);
+
+                        c->supplementary_gids = mfree(c->supplementary_gids);
+
+                        c->well_known_names = strv_free(c->well_known_names);
+
+                        bus_creds_done(c);
+
+                        free(c);
+                }
+        } else {
+                sd_bus_message *m;
+
+                m = container_of(c, sd_bus_message, creds);
+                sd_bus_message_unref(m);
+        }
+
+        return NULL;
+}
+
+_public_ uint64_t sd_bus_creds_get_mask(const sd_bus_creds *c) {
+        assert_return(c, 0);
+
+        return c->mask;
+}
+
+_public_ uint64_t sd_bus_creds_get_augmented_mask(const sd_bus_creds *c) {
+        assert_return(c, 0);
+
+        return c->augmented;
+}
+
+sd_bus_creds* bus_creds_new(void) {
+        sd_bus_creds *c;
+
+        c = new0(sd_bus_creds, 1);
+        if (!c)
+                return NULL;
+
+        c->allocated = true;
+        c->n_ref = 1;
+        return c;
+}
+
+_public_ int sd_bus_creds_new_from_pid(sd_bus_creds **ret, pid_t pid, uint64_t mask) {
+        sd_bus_creds *c;
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(mask <= _SD_BUS_CREDS_ALL, -EOPNOTSUPP);
+        assert_return(ret, -EINVAL);
+
+        if (pid == 0)
+                pid = getpid_cached();
+
+        c = bus_creds_new();
+        if (!c)
+                return -ENOMEM;
+
+        r = bus_creds_add_more(c, mask | SD_BUS_CREDS_AUGMENT, pid, 0);
+        if (r < 0) {
+                sd_bus_creds_unref(c);
+                return r;
+        }
+
+        /* Check if the process existed at all, in case we haven't
+         * figured that out already */
+        if (!pid_is_alive(pid)) {
+                sd_bus_creds_unref(c);
+                return -ESRCH;
+        }
+
+        *ret = c;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_uid(sd_bus_creds *c, uid_t *uid) {
+        assert_return(c, -EINVAL);
+        assert_return(uid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_UID))
+                return -ENODATA;
+
+        *uid = c->uid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_euid(sd_bus_creds *c, uid_t *euid) {
+        assert_return(c, -EINVAL);
+        assert_return(euid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_EUID))
+                return -ENODATA;
+
+        *euid = c->euid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_suid(sd_bus_creds *c, uid_t *suid) {
+        assert_return(c, -EINVAL);
+        assert_return(suid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_SUID))
+                return -ENODATA;
+
+        *suid = c->suid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_fsuid(sd_bus_creds *c, uid_t *fsuid) {
+        assert_return(c, -EINVAL);
+        assert_return(fsuid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_FSUID))
+                return -ENODATA;
+
+        *fsuid = c->fsuid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_gid(sd_bus_creds *c, gid_t *gid) {
+        assert_return(c, -EINVAL);
+        assert_return(gid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_GID))
+                return -ENODATA;
+
+        *gid = c->gid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_egid(sd_bus_creds *c, gid_t *egid) {
+        assert_return(c, -EINVAL);
+        assert_return(egid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_EGID))
+                return -ENODATA;
+
+        *egid = c->egid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_sgid(sd_bus_creds *c, gid_t *sgid) {
+        assert_return(c, -EINVAL);
+        assert_return(sgid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_SGID))
+                return -ENODATA;
+
+        *sgid = c->sgid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_fsgid(sd_bus_creds *c, gid_t *fsgid) {
+        assert_return(c, -EINVAL);
+        assert_return(fsgid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_FSGID))
+                return -ENODATA;
+
+        *fsgid = c->fsgid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_supplementary_gids(sd_bus_creds *c, const gid_t **gids) {
+        assert_return(c, -EINVAL);
+        assert_return(gids, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS))
+                return -ENODATA;
+
+        *gids = c->supplementary_gids;
+        return (int) c->n_supplementary_gids;
+}
+
+_public_ int sd_bus_creds_get_pid(sd_bus_creds *c, pid_t *pid) {
+        assert_return(c, -EINVAL);
+        assert_return(pid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_PID))
+                return -ENODATA;
+
+        assert(c->pid > 0);
+        *pid = c->pid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_ppid(sd_bus_creds *c, pid_t *ppid) {
+        assert_return(c, -EINVAL);
+        assert_return(ppid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_PPID))
+                return -ENODATA;
+
+        /* PID 1 has no parent process. Let's distinguish the case of
+         * not knowing and not having a parent process by the returned
+         * error code. */
+        if (c->ppid == 0)
+                return -ENXIO;
+
+        *ppid = c->ppid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_tid(sd_bus_creds *c, pid_t *tid) {
+        assert_return(c, -EINVAL);
+        assert_return(tid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_TID))
+                return -ENODATA;
+
+        assert(c->tid > 0);
+        *tid = c->tid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_selinux_context(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_SELINUX_CONTEXT))
+                return -ENODATA;
+
+        assert(c->label);
+        *ret = c->label;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_comm(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_COMM))
+                return -ENODATA;
+
+        assert(c->comm);
+        *ret = c->comm;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_tid_comm(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_TID_COMM))
+                return -ENODATA;
+
+        assert(c->tid_comm);
+        *ret = c->tid_comm;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_exe(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_EXE))
+                return -ENODATA;
+
+        if (!c->exe)
+                return -ENXIO;
+
+        *ret = c->exe;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_cgroup(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_CGROUP))
+                return -ENODATA;
+
+        assert(c->cgroup);
+        *ret = c->cgroup;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_unit(sd_bus_creds *c, const char **ret) {
+        int r;
+
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_UNIT))
+                return -ENODATA;
+
+        assert(c->cgroup);
+
+        if (!c->unit) {
+                const char *shifted;
+
+                r = cg_shift_path(c->cgroup, c->cgroup_root, &shifted);
+                if (r < 0)
+                        return r;
+
+                r = cg_path_get_unit(shifted, (char**) &c->unit);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = c->unit;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_user_unit(sd_bus_creds *c, const char **ret) {
+        int r;
+
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_USER_UNIT))
+                return -ENODATA;
+
+        assert(c->cgroup);
+
+        if (!c->user_unit) {
+                const char *shifted;
+
+                r = cg_shift_path(c->cgroup, c->cgroup_root, &shifted);
+                if (r < 0)
+                        return r;
+
+                r = cg_path_get_user_unit(shifted, (char**) &c->user_unit);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = c->user_unit;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_slice(sd_bus_creds *c, const char **ret) {
+        int r;
+
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_SLICE))
+                return -ENODATA;
+
+        assert(c->cgroup);
+
+        if (!c->slice) {
+                const char *shifted;
+
+                r = cg_shift_path(c->cgroup, c->cgroup_root, &shifted);
+                if (r < 0)
+                        return r;
+
+                r = cg_path_get_slice(shifted, (char**) &c->slice);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = c->slice;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_user_slice(sd_bus_creds *c, const char **ret) {
+        int r;
+
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_USER_SLICE))
+                return -ENODATA;
+
+        assert(c->cgroup);
+
+        if (!c->user_slice) {
+                const char *shifted;
+
+                r = cg_shift_path(c->cgroup, c->cgroup_root, &shifted);
+                if (r < 0)
+                        return r;
+
+                r = cg_path_get_user_slice(shifted, (char**) &c->user_slice);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = c->user_slice;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_session(sd_bus_creds *c, const char **ret) {
+        int r;
+
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_SESSION))
+                return -ENODATA;
+
+        assert(c->cgroup);
+
+        if (!c->session) {
+                const char *shifted;
+
+                r = cg_shift_path(c->cgroup, c->cgroup_root, &shifted);
+                if (r < 0)
+                        return r;
+
+                r = cg_path_get_session(shifted, (char**) &c->session);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = c->session;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_owner_uid(sd_bus_creds *c, uid_t *uid) {
+        const char *shifted;
+        int r;
+
+        assert_return(c, -EINVAL);
+        assert_return(uid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_OWNER_UID))
+                return -ENODATA;
+
+        assert(c->cgroup);
+
+        r = cg_shift_path(c->cgroup, c->cgroup_root, &shifted);
+        if (r < 0)
+                return r;
+
+        return cg_path_get_owner_uid(shifted, uid);
+}
+
+_public_ int sd_bus_creds_get_cmdline(sd_bus_creds *c, char ***cmdline) {
+        assert_return(c, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_CMDLINE))
+                return -ENODATA;
+
+        if (!c->cmdline)
+                return -ENXIO;
+
+        if (!c->cmdline_array) {
+                c->cmdline_array = strv_parse_nulstr(c->cmdline, c->cmdline_size);
+                if (!c->cmdline_array)
+                        return -ENOMEM;
+        }
+
+        *cmdline = c->cmdline_array;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_audit_session_id(sd_bus_creds *c, uint32_t *sessionid) {
+        assert_return(c, -EINVAL);
+        assert_return(sessionid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_AUDIT_SESSION_ID))
+                return -ENODATA;
+
+        if (!audit_session_is_valid(c->audit_session_id))
+                return -ENXIO;
+
+        *sessionid = c->audit_session_id;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_audit_login_uid(sd_bus_creds *c, uid_t *uid) {
+        assert_return(c, -EINVAL);
+        assert_return(uid, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_AUDIT_LOGIN_UID))
+                return -ENODATA;
+
+        if (!uid_is_valid(c->audit_login_uid))
+                return -ENXIO;
+
+        *uid = c->audit_login_uid;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_tty(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_TTY))
+                return -ENODATA;
+
+        if (!c->tty)
+                return -ENXIO;
+
+        *ret = c->tty;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_unique_name(sd_bus_creds *c, const char **unique_name) {
+        assert_return(c, -EINVAL);
+        assert_return(unique_name, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_UNIQUE_NAME))
+                return -ENODATA;
+
+        *unique_name = c->unique_name;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_well_known_names(sd_bus_creds *c, char ***well_known_names) {
+        assert_return(c, -EINVAL);
+        assert_return(well_known_names, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_WELL_KNOWN_NAMES))
+                return -ENODATA;
+
+        /* As a special hack we return the bus driver as well-known
+         * names list when this is requested. */
+        if (c->well_known_names_driver) {
+                static const char* const wkn[] = {
+                        "org.freedesktop.DBus",
+                        NULL
+                };
+
+                *well_known_names = (char**) wkn;
+                return 0;
+        }
+
+        if (c->well_known_names_local) {
+                static const char* const wkn[] = {
+                        "org.freedesktop.DBus.Local",
+                        NULL
+                };
+
+                *well_known_names = (char**) wkn;
+                return 0;
+        }
+
+        *well_known_names = c->well_known_names;
+        return 0;
+}
+
+_public_ int sd_bus_creds_get_description(sd_bus_creds *c, const char **ret) {
+        assert_return(c, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_DESCRIPTION))
+                return -ENODATA;
+
+        assert(c->description);
+
+        if (!c->unescaped_description) {
+                c->unescaped_description = bus_label_unescape(c->description);
+                if (!c->unescaped_description)
+                        return -ENOMEM;
+        }
+
+        *ret = c->unescaped_description;
+        return 0;
+}
+
+static int has_cap(sd_bus_creds *c, size_t offset, int capability) {
+        size_t sz;
+
+        assert(c);
+        assert(capability >= 0);
+        assert(c->capability);
+
+        unsigned lc = cap_last_cap();
+
+        if ((unsigned) capability > lc)
+                return 0;
+
+        /* If the last cap is 63, then there are 64 caps defined, and we need 2 entries á 32bit hence. *
+         * If the last cap is 64, then there are 65 caps defined, and we need 3 entries á 32bit hence. */
+        sz = DIV_ROUND_UP(lc+1, 32LU);
+
+        return !!(c->capability[offset * sz + CAP_TO_INDEX((uint32_t) capability)] & CAP_TO_MASK_CORRECTED((uint32_t) capability));
+}
+
+_public_ int sd_bus_creds_has_effective_cap(sd_bus_creds *c, int capability) {
+        assert_return(c, -EINVAL);
+        assert_return(capability >= 0, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_EFFECTIVE_CAPS))
+                return -ENODATA;
+
+        return has_cap(c, CAP_OFFSET_EFFECTIVE, capability);
+}
+
+_public_ int sd_bus_creds_has_permitted_cap(sd_bus_creds *c, int capability) {
+        assert_return(c, -EINVAL);
+        assert_return(capability >= 0, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_PERMITTED_CAPS))
+                return -ENODATA;
+
+        return has_cap(c, CAP_OFFSET_PERMITTED, capability);
+}
+
+_public_ int sd_bus_creds_has_inheritable_cap(sd_bus_creds *c, int capability) {
+        assert_return(c, -EINVAL);
+        assert_return(capability >= 0, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_INHERITABLE_CAPS))
+                return -ENODATA;
+
+        return has_cap(c, CAP_OFFSET_INHERITABLE, capability);
+}
+
+_public_ int sd_bus_creds_has_bounding_cap(sd_bus_creds *c, int capability) {
+        assert_return(c, -EINVAL);
+        assert_return(capability >= 0, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_BOUNDING_CAPS))
+                return -ENODATA;
+
+        return has_cap(c, CAP_OFFSET_BOUNDING, capability);
+}
+
+static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
+        size_t sz, max;
+        unsigned i, j;
+
+        assert(c);
+        assert(p);
+
+        max = DIV_ROUND_UP(cap_last_cap()+1, 32U);
+        p += strspn(p, WHITESPACE);
+
+        sz = strlen(p);
+        if (sz % 8 != 0)
+                return -EINVAL;
+
+        sz /= 8;
+        if (sz > max)
+                return -EINVAL;
+
+        if (!c->capability) {
+                c->capability = new0(uint32_t, max * 4);
+                if (!c->capability)
+                        return -ENOMEM;
+        }
+
+        for (i = 0; i < sz; i ++) {
+                uint32_t v = 0;
+
+                for (j = 0; j < 8; ++j) {
+                        int t;
+
+                        t = unhexchar(*p++);
+                        if (t < 0)
+                                return -EINVAL;
+
+                        v = (v << 4) | t;
+                }
+
+                c->capability[offset * max + (sz - i - 1)] = v;
+        }
+
+        return 0;
+}
+
+int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
+        uint64_t missing;
+        int r;
+
+        assert(c);
+        assert(c->allocated);
+
+        if (!(mask & SD_BUS_CREDS_AUGMENT))
+                return 0;
+
+        /* Try to retrieve PID from creds if it wasn't passed to us */
+        if (pid > 0) {
+                c->pid = pid;
+                c->mask |= SD_BUS_CREDS_PID;
+        } else if (c->mask & SD_BUS_CREDS_PID)
+                pid = c->pid;
+        else
+                /* Without pid we cannot do much... */
+                return 0;
+
+        /* Try to retrieve TID from creds if it wasn't passed to us */
+        if (tid <= 0 && (c->mask & SD_BUS_CREDS_TID))
+                tid = c->tid;
+
+        /* Calculate what we shall and can add */
+        missing = mask & ~(c->mask|SD_BUS_CREDS_PID|SD_BUS_CREDS_TID|SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_DESCRIPTION|SD_BUS_CREDS_AUGMENT);
+        if (missing == 0)
+                return 0;
+
+        if (tid > 0) {
+                c->tid = tid;
+                c->mask |= SD_BUS_CREDS_TID;
+        }
+
+        if (missing & (SD_BUS_CREDS_PPID |
+                       SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_SUID | SD_BUS_CREDS_FSUID |
+                       SD_BUS_CREDS_GID | SD_BUS_CREDS_EGID | SD_BUS_CREDS_SGID | SD_BUS_CREDS_FSGID |
+                       SD_BUS_CREDS_SUPPLEMENTARY_GIDS |
+                       SD_BUS_CREDS_EFFECTIVE_CAPS | SD_BUS_CREDS_INHERITABLE_CAPS |
+                       SD_BUS_CREDS_PERMITTED_CAPS | SD_BUS_CREDS_BOUNDING_CAPS)) {
+
+                _cleanup_fclose_ FILE *f = NULL;
+                const char *p;
+
+                p = procfs_file_alloca(pid, "status");
+
+                f = fopen(p, "re");
+                if (!f) {
+                        if (errno == ENOENT)
+                                return -ESRCH;
+                        else if (!ERRNO_IS_PRIVILEGE(errno))
+                                return -errno;
+                } else {
+
+                        for (;;) {
+                                _cleanup_free_ char *line = NULL;
+
+                                r = read_line(f, LONG_LINE_MAX, &line);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0)
+                                        break;
+
+                                if (missing & SD_BUS_CREDS_PPID) {
+                                        p = startswith(line, "PPid:");
+                                        if (p) {
+                                                p += strspn(p, WHITESPACE);
+
+                                                /* Explicitly check for PPID 0 (which is the case for PID 1) */
+                                                if (!streq(p, "0")) {
+                                                        r = parse_pid(p, &c->ppid);
+                                                        if (r < 0)
+                                                                return r;
+
+                                                } else
+                                                        c->ppid = 0;
+
+                                                c->mask |= SD_BUS_CREDS_PPID;
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID)) {
+                                        p = startswith(line, "Uid:");
+                                        if (p) {
+                                                unsigned long uid, euid, suid, fsuid;
+
+                                                p += strspn(p, WHITESPACE);
+                                                if (sscanf(p, "%lu %lu %lu %lu", &uid, &euid, &suid, &fsuid) != 4)
+                                                        return -EIO;
+
+                                                if (missing & SD_BUS_CREDS_UID)
+                                                        c->uid = (uid_t) uid;
+                                                if (missing & SD_BUS_CREDS_EUID)
+                                                        c->euid = (uid_t) euid;
+                                                if (missing & SD_BUS_CREDS_SUID)
+                                                        c->suid = (uid_t) suid;
+                                                if (missing & SD_BUS_CREDS_FSUID)
+                                                        c->fsuid = (uid_t) fsuid;
+
+                                                c->mask |= missing & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID);
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & (SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID)) {
+                                        p = startswith(line, "Gid:");
+                                        if (p) {
+                                                unsigned long gid, egid, sgid, fsgid;
+
+                                                p += strspn(p, WHITESPACE);
+                                                if (sscanf(p, "%lu %lu %lu %lu", &gid, &egid, &sgid, &fsgid) != 4)
+                                                        return -EIO;
+
+                                                if (missing & SD_BUS_CREDS_GID)
+                                                        c->gid = (gid_t) gid;
+                                                if (missing & SD_BUS_CREDS_EGID)
+                                                        c->egid = (gid_t) egid;
+                                                if (missing & SD_BUS_CREDS_SGID)
+                                                        c->sgid = (gid_t) sgid;
+                                                if (missing & SD_BUS_CREDS_FSGID)
+                                                        c->fsgid = (gid_t) fsgid;
+
+                                                c->mask |= missing & (SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID);
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) {
+                                        p = startswith(line, "Groups:");
+                                        if (p) {
+                                                size_t allocated = 0;
+
+                                                for (;;) {
+                                                        unsigned long g;
+                                                        int n = 0;
+
+                                                        p += strspn(p, WHITESPACE);
+                                                        if (*p == 0)
+                                                                break;
+
+                                                        if (sscanf(p, "%lu%n", &g, &n) != 1)
+                                                                return -EIO;
+
+                                                        if (!GREEDY_REALLOC(c->supplementary_gids, allocated, c->n_supplementary_gids+1))
+                                                                return -ENOMEM;
+
+                                                        c->supplementary_gids[c->n_supplementary_gids++] = (gid_t) g;
+                                                        p += n;
+                                                }
+
+                                                c->mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & SD_BUS_CREDS_EFFECTIVE_CAPS) {
+                                        p = startswith(line, "CapEff:");
+                                        if (p) {
+                                                r = parse_caps(c, CAP_OFFSET_EFFECTIVE, p);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->mask |= SD_BUS_CREDS_EFFECTIVE_CAPS;
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & SD_BUS_CREDS_PERMITTED_CAPS) {
+                                        p = startswith(line, "CapPrm:");
+                                        if (p) {
+                                                r = parse_caps(c, CAP_OFFSET_PERMITTED, p);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->mask |= SD_BUS_CREDS_PERMITTED_CAPS;
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & SD_BUS_CREDS_INHERITABLE_CAPS) {
+                                        p = startswith(line, "CapInh:");
+                                        if (p) {
+                                                r = parse_caps(c, CAP_OFFSET_INHERITABLE, p);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->mask |= SD_BUS_CREDS_INHERITABLE_CAPS;
+                                                continue;
+                                        }
+                                }
+
+                                if (missing & SD_BUS_CREDS_BOUNDING_CAPS) {
+                                        p = startswith(line, "CapBnd:");
+                                        if (p) {
+                                                r = parse_caps(c, CAP_OFFSET_BOUNDING, p);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->mask |= SD_BUS_CREDS_BOUNDING_CAPS;
+                                                continue;
+                                        }
+                                }
+                        }
+                }
+        }
+
+        if (missing & SD_BUS_CREDS_SELINUX_CONTEXT) {
+                const char *p;
+
+                p = procfs_file_alloca(pid, "attr/current");
+                r = read_one_line_file(p, &c->label);
+                if (r < 0) {
+                        if (!IN_SET(r, -ENOENT, -EINVAL, -EPERM, -EACCES))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+        }
+
+        if (missing & SD_BUS_CREDS_COMM) {
+                r = get_process_comm(pid, &c->comm);
+                if (r < 0) {
+                        if (!ERRNO_IS_PRIVILEGE(r))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_COMM;
+        }
+
+        if (missing & SD_BUS_CREDS_EXE) {
+                r = get_process_exe(pid, &c->exe);
+                if (r == -ESRCH) {
+                        /* Unfortunately we cannot really distinguish
+                         * the case here where the process does not
+                         * exist, and /proc/$PID/exe being unreadable
+                         * because $PID is a kernel thread. Hence,
+                         * assume it is a kernel thread, and rely on
+                         * that this case is caught with a later
+                         * call. */
+                        c->exe = NULL;
+                        c->mask |= SD_BUS_CREDS_EXE;
+                } else if (r < 0) {
+                        if (!ERRNO_IS_PRIVILEGE(r))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_EXE;
+        }
+
+        if (missing & SD_BUS_CREDS_CMDLINE) {
+                const char *p;
+
+                p = procfs_file_alloca(pid, "cmdline");
+                r = read_full_file(p, &c->cmdline, &c->cmdline_size);
+                if (r == -ENOENT)
+                        return -ESRCH;
+                if (r < 0) {
+                        if (!ERRNO_IS_PRIVILEGE(r))
+                                return r;
+                } else {
+                        if (c->cmdline_size == 0)
+                                c->cmdline = mfree(c->cmdline);
+
+                        c->mask |= SD_BUS_CREDS_CMDLINE;
+                }
+        }
+
+        if (tid > 0 && (missing & SD_BUS_CREDS_TID_COMM)) {
+                _cleanup_free_ char *p = NULL;
+
+                if (asprintf(&p, "/proc/"PID_FMT"/task/"PID_FMT"/comm", pid, tid) < 0)
+                        return -ENOMEM;
+
+                r = read_one_line_file(p, &c->tid_comm);
+                if (r == -ENOENT)
+                        return -ESRCH;
+                if (r < 0) {
+                        if (!ERRNO_IS_PRIVILEGE(r))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_TID_COMM;
+        }
+
+        if (missing & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_USER_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID)) {
+
+                if (!c->cgroup) {
+                        r = cg_pid_get_path(NULL, pid, &c->cgroup);
+                        if (r < 0) {
+                                if (!ERRNO_IS_PRIVILEGE(r))
+                                        return r;
+                        }
+                }
+
+                if (!c->cgroup_root) {
+                        r = cg_get_root_path(&c->cgroup_root);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (c->cgroup)
+                        c->mask |= missing & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_USER_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID);
+        }
+
+        if (missing & SD_BUS_CREDS_AUDIT_SESSION_ID) {
+                r = audit_session_from_pid(pid, &c->audit_session_id);
+                if (r == -ENODATA) {
+                        /* ENODATA means: no audit session id assigned */
+                        c->audit_session_id = AUDIT_SESSION_INVALID;
+                        c->mask |= SD_BUS_CREDS_AUDIT_SESSION_ID;
+                } else if (r < 0) {
+                        if (!IN_SET(r, -EOPNOTSUPP, -ENOENT, -EPERM, -EACCES))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_AUDIT_SESSION_ID;
+        }
+
+        if (missing & SD_BUS_CREDS_AUDIT_LOGIN_UID) {
+                r = audit_loginuid_from_pid(pid, &c->audit_login_uid);
+                if (r == -ENODATA) {
+                        /* ENODATA means: no audit login uid assigned */
+                        c->audit_login_uid = UID_INVALID;
+                        c->mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID;
+                } else if (r < 0) {
+                        if (!IN_SET(r, -EOPNOTSUPP, -ENOENT, -EPERM, -EACCES))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID;
+        }
+
+        if (missing & SD_BUS_CREDS_TTY) {
+                r = get_ctty(pid, NULL, &c->tty);
+                if (r == -ENXIO) {
+                        /* ENXIO means: process has no controlling TTY */
+                        c->tty = NULL;
+                        c->mask |= SD_BUS_CREDS_TTY;
+                } else if (r < 0) {
+                        if (!IN_SET(r, -EPERM, -EACCES, -ENOENT))
+                                return r;
+                } else
+                        c->mask |= SD_BUS_CREDS_TTY;
+        }
+
+        /* In case only the exe path was to be read we cannot
+         * distinguish the case where the exe path was unreadable
+         * because the process was a kernel thread, or when the
+         * process didn't exist at all. Hence, let's do a final check,
+         * to be sure. */
+        if (!pid_is_alive(pid))
+                return -ESRCH;
+
+        if (tid > 0 && tid != pid && !pid_is_unwaited(tid))
+                return -ESRCH;
+
+        c->augmented = missing & c->mask;
+
+        return 0;
+}
+
+int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret) {
+        _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *n = NULL;
+        int r;
+
+        assert(c);
+        assert(ret);
+
+        if ((mask & ~c->mask) == 0 || (!(mask & SD_BUS_CREDS_AUGMENT))) {
+                /* There's already all data we need, or augmentation
+                 * wasn't turned on. */
+
+                *ret = sd_bus_creds_ref(c);
+                return 0;
+        }
+
+        n = bus_creds_new();
+        if (!n)
+                return -ENOMEM;
+
+        /* Copy the original data over */
+
+        if (c->mask & mask & SD_BUS_CREDS_PID) {
+                n->pid = c->pid;
+                n->mask |= SD_BUS_CREDS_PID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_TID) {
+                n->tid = c->tid;
+                n->mask |= SD_BUS_CREDS_TID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_PPID) {
+                n->ppid = c->ppid;
+                n->mask |= SD_BUS_CREDS_PPID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_UID) {
+                n->uid = c->uid;
+                n->mask |= SD_BUS_CREDS_UID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_EUID) {
+                n->euid = c->euid;
+                n->mask |= SD_BUS_CREDS_EUID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_SUID) {
+                n->suid = c->suid;
+                n->mask |= SD_BUS_CREDS_SUID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_FSUID) {
+                n->fsuid = c->fsuid;
+                n->mask |= SD_BUS_CREDS_FSUID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_GID) {
+                n->gid = c->gid;
+                n->mask |= SD_BUS_CREDS_GID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_EGID) {
+                n->egid = c->egid;
+                n->mask |= SD_BUS_CREDS_EGID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_SGID) {
+                n->sgid = c->sgid;
+                n->mask |= SD_BUS_CREDS_SGID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_FSGID) {
+                n->fsgid = c->fsgid;
+                n->mask |= SD_BUS_CREDS_FSGID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) {
+                if (c->supplementary_gids) {
+                        n->supplementary_gids = newdup(gid_t, c->supplementary_gids, c->n_supplementary_gids);
+                        if (!n->supplementary_gids)
+                                return -ENOMEM;
+                        n->n_supplementary_gids = c->n_supplementary_gids;
+                } else {
+                        n->supplementary_gids = NULL;
+                        n->n_supplementary_gids = 0;
+                }
+
+                n->mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_COMM) {
+                assert(c->comm);
+
+                n->comm = strdup(c->comm);
+                if (!n->comm)
+                        return -ENOMEM;
+
+                n->mask |= SD_BUS_CREDS_COMM;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_TID_COMM) {
+                assert(c->tid_comm);
+
+                n->tid_comm = strdup(c->tid_comm);
+                if (!n->tid_comm)
+                        return -ENOMEM;
+
+                n->mask |= SD_BUS_CREDS_TID_COMM;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_EXE) {
+                if (c->exe) {
+                        n->exe = strdup(c->exe);
+                        if (!n->exe)
+                                return -ENOMEM;
+                } else
+                        n->exe = NULL;
+
+                n->mask |= SD_BUS_CREDS_EXE;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_CMDLINE) {
+                if (c->cmdline) {
+                        n->cmdline = memdup(c->cmdline, c->cmdline_size);
+                        if (!n->cmdline)
+                                return -ENOMEM;
+
+                        n->cmdline_size = c->cmdline_size;
+                } else {
+                        n->cmdline = NULL;
+                        n->cmdline_size = 0;
+                }
+
+                n->mask |= SD_BUS_CREDS_CMDLINE;
+        }
+
+        if (c->mask & mask & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_USER_SLICE|SD_BUS_CREDS_OWNER_UID)) {
+                assert(c->cgroup);
+
+                n->cgroup = strdup(c->cgroup);
+                if (!n->cgroup)
+                        return -ENOMEM;
+
+                n->cgroup_root = strdup(c->cgroup_root);
+                if (!n->cgroup_root)
+                        return -ENOMEM;
+
+                n->mask |= mask & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_USER_SLICE|SD_BUS_CREDS_OWNER_UID);
+        }
+
+        if (c->mask & mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS)) {
+                assert(c->capability);
+
+                n->capability = memdup(c->capability, DIV_ROUND_UP(cap_last_cap()+1, 32U) * 4 * 4);
+                if (!n->capability)
+                        return -ENOMEM;
+
+                n->mask |= c->mask & mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS);
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_SELINUX_CONTEXT) {
+                assert(c->label);
+
+                n->label = strdup(c->label);
+                if (!n->label)
+                        return -ENOMEM;
+                n->mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_AUDIT_SESSION_ID) {
+                n->audit_session_id = c->audit_session_id;
+                n->mask |= SD_BUS_CREDS_AUDIT_SESSION_ID;
+        }
+        if (c->mask & mask & SD_BUS_CREDS_AUDIT_LOGIN_UID) {
+                n->audit_login_uid = c->audit_login_uid;
+                n->mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_TTY) {
+                if (c->tty) {
+                        n->tty = strdup(c->tty);
+                        if (!n->tty)
+                                return -ENOMEM;
+                } else
+                        n->tty = NULL;
+                n->mask |= SD_BUS_CREDS_TTY;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_UNIQUE_NAME) {
+                assert(c->unique_name);
+
+                n->unique_name = strdup(c->unique_name);
+                if (!n->unique_name)
+                        return -ENOMEM;
+                n->mask |= SD_BUS_CREDS_UNIQUE_NAME;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_WELL_KNOWN_NAMES) {
+                if (strv_isempty(c->well_known_names))
+                        n->well_known_names = NULL;
+                else {
+                        n->well_known_names = strv_copy(c->well_known_names);
+                        if (!n->well_known_names)
+                                return -ENOMEM;
+                }
+                n->well_known_names_driver = c->well_known_names_driver;
+                n->well_known_names_local = c->well_known_names_local;
+                n->mask |= SD_BUS_CREDS_WELL_KNOWN_NAMES;
+        }
+
+        if (c->mask & mask & SD_BUS_CREDS_DESCRIPTION) {
+                assert(c->description);
+                n->description = strdup(c->description);
+                if (!n->description)
+                        return -ENOMEM;
+                n->mask |= SD_BUS_CREDS_DESCRIPTION;
+        }
+
+        n->augmented = c->augmented & n->mask;
+
+        /* Get more data */
+
+        r = bus_creds_add_more(n, mask, 0, 0);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(n);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/bus-creds.h b/src/libsystemd/sd-bus/bus-creds.h
new file mode 100644
index 0000000..7806d9e
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-creds.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+#include "sd-bus.h"
+
+struct sd_bus_creds {
+        bool allocated;
+        unsigned n_ref;
+
+        uint64_t mask;
+        uint64_t augmented;
+
+        uid_t uid;
+        uid_t euid;
+        uid_t suid;
+        uid_t fsuid;
+        gid_t gid;
+        gid_t egid;
+        gid_t sgid;
+        gid_t fsgid;
+
+        gid_t *supplementary_gids;
+        unsigned n_supplementary_gids;
+
+        pid_t ppid;
+        pid_t pid;
+        pid_t tid;
+
+        char *comm;
+        char *tid_comm;
+        char *exe;
+
+        char *cmdline;
+        size_t cmdline_size;
+        char **cmdline_array;
+
+        char *cgroup;
+        char *session;
+        char *unit;
+        char *user_unit;
+        char *slice;
+        char *user_slice;
+
+        char *tty;
+
+        uint32_t *capability;
+
+        uint32_t audit_session_id;
+        uid_t audit_login_uid;
+
+        char *label;
+
+        char *unique_name;
+
+        char **well_known_names;
+        bool well_known_names_driver:1;
+        bool well_known_names_local:1;
+
+        char *cgroup_root;
+
+        char *description, *unescaped_description;
+};
+
+sd_bus_creds* bus_creds_new(void);
+
+void bus_creds_done(sd_bus_creds *c);
+
+int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid);
+
+int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret);
diff --git a/src/libsystemd/sd-bus/bus-dump.c b/src/libsystemd/sd-bus/bus-dump.c
new file mode 100644
index 0000000..3ff87be
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-dump.c
@@ -0,0 +1,592 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/time.h>
+
+#include "alloc-util.h"
+#include "bus-dump.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-type.h"
+#include "cap-list.h"
+#include "capability-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "locale-util.h"
+#include "macro.h"
+#include "string-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "util.h"
+
+static char *indent(unsigned level, uint64_t flags) {
+        char *p;
+        unsigned n, i = 0;
+
+        n = 0;
+
+        if (flags & SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY && level > 0)
+                level -= 1;
+
+        if (flags & SD_BUS_MESSAGE_DUMP_WITH_HEADER)
+                n += 2;
+
+        p = new(char, n + level*8 + 1);
+        if (!p)
+                return NULL;
+
+        if (flags & SD_BUS_MESSAGE_DUMP_WITH_HEADER) {
+                p[i++] = ' ';
+                p[i++] = ' ';
+        }
+
+        memset(p + i, ' ', level*8);
+        p[i + level*8] = 0;
+
+        return p;
+}
+
+_public_ int sd_bus_message_dump(sd_bus_message *m, FILE *f, uint64_t flags) {
+        unsigned level = 1;
+        int r;
+
+        assert(m);
+
+        if (!f)
+                f = stdout;
+
+        if (flags & SD_BUS_MESSAGE_DUMP_WITH_HEADER) {
+                fprintf(f,
+                        "%s%s%s Type=%s%s%s  Endian=%c  Flags=%u  Version=%u",
+                        m->header->type == SD_BUS_MESSAGE_METHOD_ERROR ? ansi_highlight_red() :
+                        m->header->type == SD_BUS_MESSAGE_METHOD_RETURN ? ansi_highlight_green() :
+                        m->header->type != SD_BUS_MESSAGE_SIGNAL ? ansi_highlight() : "",
+                        special_glyph(SPECIAL_GLYPH_TRIANGULAR_BULLET),
+                        ansi_normal(),
+
+                        ansi_highlight(),
+                        bus_message_type_to_string(m->header->type) ?: "(unknown)",
+                        ansi_normal(),
+
+                        m->header->endian,
+                        m->header->flags,
+                        m->header->version);
+
+                /* Display synthetic message serial number in a more readable
+                 * format than (uint32_t) -1 */
+                if (BUS_MESSAGE_COOKIE(m) == 0xFFFFFFFFULL)
+                        fprintf(f, " Cookie=-1");
+                else
+                        fprintf(f, " Cookie=%" PRIu64, BUS_MESSAGE_COOKIE(m));
+
+                if (m->reply_cookie != 0)
+                        fprintf(f, "  ReplyCookie=%" PRIu64, m->reply_cookie);
+
+                fputs("\n", f);
+
+                if (m->sender)
+                        fprintf(f, "  Sender=%s%s%s", ansi_highlight(), m->sender, ansi_normal());
+                if (m->destination)
+                        fprintf(f, "  Destination=%s%s%s", ansi_highlight(), m->destination, ansi_normal());
+                if (m->path)
+                        fprintf(f, "  Path=%s%s%s", ansi_highlight(), m->path, ansi_normal());
+                if (m->interface)
+                        fprintf(f, "  Interface=%s%s%s", ansi_highlight(), m->interface, ansi_normal());
+                if (m->member)
+                        fprintf(f, "  Member=%s%s%s", ansi_highlight(), m->member, ansi_normal());
+
+                if (m->sender || m->destination || m->path || m->interface || m->member)
+                        fputs("\n", f);
+
+                if (sd_bus_error_is_set(&m->error))
+                        fprintf(f,
+                                "  ErrorName=%s%s%s"
+                                "  ErrorMessage=%s\"%s\"%s\n",
+                                ansi_highlight_red(), strna(m->error.name), ansi_normal(),
+                                ansi_highlight_red(), strna(m->error.message), ansi_normal());
+
+                if (m->monotonic != 0)
+                        fprintf(f, "  Monotonic="USEC_FMT, m->monotonic);
+                if (m->realtime != 0)
+                        fprintf(f, "  Realtime="USEC_FMT, m->realtime);
+                if (m->seqnum != 0)
+                        fprintf(f, "  SequenceNumber=%"PRIu64, m->seqnum);
+
+                if (m->monotonic != 0 || m->realtime != 0 || m->seqnum != 0)
+                        fputs("\n", f);
+
+                bus_creds_dump(&m->creds, f, true);
+        }
+
+        r = sd_bus_message_rewind(m, !(flags & SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY));
+        if (r < 0)
+                return log_error_errno(r, "Failed to rewind: %m");
+
+        if (!(flags & SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY)) {
+                _cleanup_free_ char *prefix = NULL;
+
+                prefix = indent(0, flags);
+                if (!prefix)
+                        return log_oom();
+
+                fprintf(f, "%sMESSAGE \"%s\" {\n", prefix, strempty(m->root_container.signature));
+        }
+
+        for (;;) {
+                _cleanup_free_ char *prefix = NULL;
+                const char *contents = NULL;
+                char type;
+                union {
+                        uint8_t u8;
+                        uint16_t u16;
+                        int16_t s16;
+                        uint32_t u32;
+                        int32_t s32;
+                        uint64_t u64;
+                        int64_t s64;
+                        double d64;
+                        const char *string;
+                        int i;
+                } basic;
+
+                r = sd_bus_message_peek_type(m, &type, &contents);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to peek type: %m");
+
+                if (r == 0) {
+                        if (level <= 1)
+                                break;
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to exit container: %m");
+
+                        level--;
+
+                        prefix = indent(level, flags);
+                        if (!prefix)
+                                return log_oom();
+
+                        fprintf(f, "%s};\n", prefix);
+                        continue;
+                }
+
+                prefix = indent(level, flags);
+                if (!prefix)
+                        return log_oom();
+
+                if (bus_type_is_container(type) > 0) {
+                        r = sd_bus_message_enter_container(m, type, contents);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to enter container: %m");
+
+                        if (type == SD_BUS_TYPE_ARRAY)
+                                fprintf(f, "%sARRAY \"%s\" {\n", prefix, contents);
+                        else if (type == SD_BUS_TYPE_VARIANT)
+                                fprintf(f, "%sVARIANT \"%s\" {\n", prefix, contents);
+                        else if (type == SD_BUS_TYPE_STRUCT)
+                                fprintf(f, "%sSTRUCT \"%s\" {\n", prefix, contents);
+                        else if (type == SD_BUS_TYPE_DICT_ENTRY)
+                                fprintf(f, "%sDICT_ENTRY \"%s\" {\n", prefix, contents);
+
+                        level++;
+
+                        continue;
+                }
+
+                r = sd_bus_message_read_basic(m, type, &basic);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to get basic: %m");
+
+                assert(r > 0);
+
+                switch (type) {
+
+                case SD_BUS_TYPE_BYTE:
+                        fprintf(f, "%sBYTE %s%u%s;\n", prefix, ansi_highlight(), basic.u8, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_BOOLEAN:
+                        fprintf(f, "%sBOOLEAN %s%s%s;\n", prefix, ansi_highlight(), true_false(basic.i), ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_INT16:
+                        fprintf(f, "%sINT16 %s%i%s;\n", prefix, ansi_highlight(), basic.s16, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_UINT16:
+                        fprintf(f, "%sUINT16 %s%u%s;\n", prefix, ansi_highlight(), basic.u16, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_INT32:
+                        fprintf(f, "%sINT32 %s%i%s;\n", prefix, ansi_highlight(), basic.s32, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_UINT32:
+                        fprintf(f, "%sUINT32 %s%u%s;\n", prefix, ansi_highlight(), basic.u32, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_INT64:
+                        fprintf(f, "%sINT64 %s%"PRIi64"%s;\n", prefix, ansi_highlight(), basic.s64, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_UINT64:
+                        fprintf(f, "%sUINT64 %s%"PRIu64"%s;\n", prefix, ansi_highlight(), basic.u64, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_DOUBLE:
+                        fprintf(f, "%sDOUBLE %s%g%s;\n", prefix, ansi_highlight(), basic.d64, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_STRING:
+                        fprintf(f, "%sSTRING \"%s%s%s\";\n", prefix, ansi_highlight(), basic.string, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_OBJECT_PATH:
+                        fprintf(f, "%sOBJECT_PATH \"%s%s%s\";\n", prefix, ansi_highlight(), basic.string, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_SIGNATURE:
+                        fprintf(f, "%sSIGNATURE \"%s%s%s\";\n", prefix, ansi_highlight(), basic.string, ansi_normal());
+                        break;
+
+                case SD_BUS_TYPE_UNIX_FD:
+                        fprintf(f, "%sUNIX_FD %s%i%s;\n", prefix, ansi_highlight(), basic.i, ansi_normal());
+                        break;
+
+                default:
+                        assert_not_reached("Unknown basic type.");
+                }
+        }
+
+        if (!(flags & SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY)) {
+                _cleanup_free_ char *prefix = NULL;
+
+                prefix = indent(0, flags);
+                if (!prefix)
+                        return log_oom();
+
+                fprintf(f, "%s};\n\n", prefix);
+        }
+
+        return 0;
+}
+
+static void dump_capabilities(
+                sd_bus_creds *c,
+                FILE *f,
+                const char *name,
+                bool terse,
+                int (*has)(sd_bus_creds *c, int capability)) {
+
+        unsigned long i, last_cap;
+        unsigned n = 0;
+        int r;
+
+        assert(c);
+        assert(f);
+        assert(name);
+        assert(has);
+
+        i = 0;
+        r = has(c, i);
+        if (r < 0)
+                return;
+
+        fprintf(f, "%s%s=%s", terse ? "  " : "", name, terse ? "" : ansi_highlight());
+        last_cap = cap_last_cap();
+
+        for (;;) {
+                if (r > 0) {
+
+                        if (n > 0)
+                                fputc(' ', f);
+                        if (n % 4 == 3)
+                                fprintf(f, terse ? "\n          " : "\n        ");
+
+                        fprintf(f, "%s", strna(capability_to_name(i)));
+                        n++;
+                }
+
+                i++;
+
+                if (i > last_cap)
+                        break;
+
+                r = has(c, i);
+        }
+
+        fputs("\n", f);
+
+        if (!terse)
+                fputs(ansi_normal(), f);
+}
+
+int bus_creds_dump(sd_bus_creds *c, FILE *f, bool terse) {
+        uid_t owner, audit_loginuid;
+        uint32_t audit_sessionid;
+        char **cmdline = NULL, **well_known = NULL;
+        const char *prefix, *color, *suffix, *s;
+        int r, q, v, w, z;
+
+        assert(c);
+
+        if (!f)
+                f = stdout;
+
+        if (terse) {
+                prefix = "  ";
+                suffix = "";
+                color = "";
+        } else {
+                const char *off;
+
+                prefix = "";
+                color = ansi_highlight();
+
+                off = ansi_normal();
+                suffix = strjoina(off, "\n");
+        }
+
+        if (c->mask & SD_BUS_CREDS_PID)
+                fprintf(f, "%sPID=%s"PID_FMT"%s", prefix, color, c->pid, suffix);
+        if (c->mask & SD_BUS_CREDS_TID)
+                fprintf(f, "%sTID=%s"PID_FMT"%s", prefix, color, c->tid, suffix);
+        if (c->mask & SD_BUS_CREDS_PPID) {
+                if (c->ppid == 0)
+                        fprintf(f, "%sPPID=%sn/a%s", prefix, color, suffix);
+                else
+                        fprintf(f, "%sPPID=%s"PID_FMT"%s", prefix, color, c->ppid, suffix);
+        }
+        if (c->mask & SD_BUS_CREDS_TTY)
+                fprintf(f, "%sTTY=%s%s%s", prefix, color, strna(c->tty), suffix);
+
+        if (terse && ((c->mask & (SD_BUS_CREDS_PID|SD_BUS_CREDS_TID|SD_BUS_CREDS_PPID|SD_BUS_CREDS_TTY))))
+                fputs("\n", f);
+
+        if (c->mask & SD_BUS_CREDS_UID)
+                fprintf(f, "%sUID=%s"UID_FMT"%s", prefix, color, c->uid, suffix);
+        if (c->mask & SD_BUS_CREDS_EUID)
+                fprintf(f, "%sEUID=%s"UID_FMT"%s", prefix, color, c->euid, suffix);
+        if (c->mask & SD_BUS_CREDS_SUID)
+                fprintf(f, "%sSUID=%s"UID_FMT"%s", prefix, color, c->suid, suffix);
+        if (c->mask & SD_BUS_CREDS_FSUID)
+                fprintf(f, "%sFSUID=%s"UID_FMT"%s", prefix, color, c->fsuid, suffix);
+        r = sd_bus_creds_get_owner_uid(c, &owner);
+        if (r >= 0)
+                fprintf(f, "%sOwnerUID=%s"UID_FMT"%s", prefix, color, owner, suffix);
+        if (c->mask & SD_BUS_CREDS_GID)
+                fprintf(f, "%sGID=%s"GID_FMT"%s", prefix, color, c->gid, suffix);
+        if (c->mask & SD_BUS_CREDS_EGID)
+                fprintf(f, "%sEGID=%s"GID_FMT"%s", prefix, color, c->egid, suffix);
+        if (c->mask & SD_BUS_CREDS_SGID)
+                fprintf(f, "%sSGID=%s"GID_FMT"%s", prefix, color, c->sgid, suffix);
+        if (c->mask & SD_BUS_CREDS_FSGID)
+                fprintf(f, "%sFSGID=%s"GID_FMT"%s", prefix, color, c->fsgid, suffix);
+
+        if (c->mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) {
+                unsigned i;
+
+                fprintf(f, "%sSupplementaryGIDs=%s", prefix, color);
+                for (i = 0; i < c->n_supplementary_gids; i++)
+                        fprintf(f, "%s" GID_FMT, i > 0 ? " " : "", c->supplementary_gids[i]);
+                fprintf(f, "%s", suffix);
+        }
+
+        if (terse && ((c->mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+                                  SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
+                                  SD_BUS_CREDS_SUPPLEMENTARY_GIDS)) || r >= 0))
+                fputs("\n", f);
+
+        if (c->mask & SD_BUS_CREDS_COMM)
+                fprintf(f, "%sComm=%s%s%s", prefix, color, c->comm, suffix);
+        if (c->mask & SD_BUS_CREDS_TID_COMM)
+                fprintf(f, "%sTIDComm=%s%s%s", prefix, color, c->tid_comm, suffix);
+        if (c->mask & SD_BUS_CREDS_EXE)
+                fprintf(f, "%sExe=%s%s%s", prefix, color, strna(c->exe), suffix);
+
+        if (terse && (c->mask & (SD_BUS_CREDS_EXE|SD_BUS_CREDS_COMM|SD_BUS_CREDS_TID_COMM)))
+                fputs("\n", f);
+
+        r = sd_bus_creds_get_cmdline(c, &cmdline);
+        if (r >= 0) {
+                char **i;
+
+                fprintf(f, "%sCommandLine=%s", prefix, color);
+                STRV_FOREACH(i, cmdline) {
+                        if (i != cmdline)
+                                fputc(' ', f);
+
+                        fputs(*i, f);
+                }
+
+                fprintf(f, "%s", suffix);
+        } else if (r != -ENODATA)
+                fprintf(f, "%sCommandLine=%sn/a%s", prefix, color, suffix);
+
+        if (c->mask & SD_BUS_CREDS_SELINUX_CONTEXT)
+                fprintf(f, "%sLabel=%s%s%s", prefix, color, c->label, suffix);
+        if (c->mask & SD_BUS_CREDS_DESCRIPTION)
+                fprintf(f, "%sDescription=%s%s%s", prefix, color, c->description, suffix);
+
+        if (terse && (c->mask & (SD_BUS_CREDS_SELINUX_CONTEXT|SD_BUS_CREDS_DESCRIPTION)))
+                fputs("\n", f);
+
+        if (c->mask & SD_BUS_CREDS_CGROUP)
+                fprintf(f, "%sCGroup=%s%s%s", prefix, color, c->cgroup, suffix);
+        s = NULL;
+        r = sd_bus_creds_get_unit(c, &s);
+        if (r != -ENODATA)
+                fprintf(f, "%sUnit=%s%s%s", prefix, color, strna(s), suffix);
+        s = NULL;
+        v = sd_bus_creds_get_slice(c, &s);
+        if (v != -ENODATA)
+                fprintf(f, "%sSlice=%s%s%s", prefix, color, strna(s), suffix);
+        s = NULL;
+        q = sd_bus_creds_get_user_unit(c, &s);
+        if (q != -ENODATA)
+                fprintf(f, "%sUserUnit=%s%s%s", prefix, color, strna(s), suffix);
+        s = NULL;
+        w = sd_bus_creds_get_user_slice(c, &s);
+        if (w != -ENODATA)
+                fprintf(f, "%sUserSlice=%s%s%s", prefix, color, strna(s), suffix);
+        s = NULL;
+        z = sd_bus_creds_get_session(c, &s);
+        if (z != -ENODATA)
+                fprintf(f, "%sSession=%s%s%s", prefix, color, strna(s), suffix);
+
+        if (terse && ((c->mask & SD_BUS_CREDS_CGROUP) || r != -ENODATA || q != -ENODATA || v != -ENODATA || w != -ENODATA || z != -ENODATA))
+                fputs("\n", f);
+
+        r = sd_bus_creds_get_audit_login_uid(c, &audit_loginuid);
+        if (r >= 0)
+                fprintf(f, "%sAuditLoginUID=%s"UID_FMT"%s", prefix, color, audit_loginuid, suffix);
+        else if (r != -ENODATA)
+                fprintf(f, "%sAuditLoginUID=%sn/a%s", prefix, color, suffix);
+        q = sd_bus_creds_get_audit_session_id(c, &audit_sessionid);
+        if (q >= 0)
+                fprintf(f, "%sAuditSessionID=%s%"PRIu32"%s", prefix, color, audit_sessionid, suffix);
+        else if (q != -ENODATA)
+                fprintf(f, "%sAuditSessionID=%sn/a%s", prefix, color, suffix);
+
+        if (terse && (r != -ENODATA || q != -ENODATA))
+                fputs("\n", f);
+
+        if (c->mask & SD_BUS_CREDS_UNIQUE_NAME)
+                fprintf(f, "%sUniqueName=%s%s%s", prefix, color, c->unique_name, suffix);
+
+        if (sd_bus_creds_get_well_known_names(c, &well_known) >= 0) {
+                char **i;
+
+                fprintf(f, "%sWellKnownNames=%s", prefix, color);
+                STRV_FOREACH(i, well_known) {
+                        if (i != well_known)
+                                fputc(' ', f);
+
+                        fputs(*i, f);
+                }
+
+                fprintf(f, "%s", suffix);
+        }
+
+        if (terse && (c->mask & SD_BUS_CREDS_UNIQUE_NAME || well_known))
+                fputc('\n', f);
+
+        dump_capabilities(c, f, "EffectiveCapabilities", terse, sd_bus_creds_has_effective_cap);
+        dump_capabilities(c, f, "PermittedCapabilities", terse, sd_bus_creds_has_permitted_cap);
+        dump_capabilities(c, f, "InheritableCapabilities", terse, sd_bus_creds_has_inheritable_cap);
+        dump_capabilities(c, f, "BoundingCapabilities", terse, sd_bus_creds_has_bounding_cap);
+
+        return 0;
+}
+
+/*
+ * For details about the file format, see:
+ *
+ * http://wiki.wireshark.org/Development/LibpcapFileFormat
+ */
+
+typedef struct _packed_ pcap_hdr_s {
+        uint32_t magic_number;   /* magic number */
+        uint16_t version_major;  /* major version number */
+        uint16_t version_minor;  /* minor version number */
+        int32_t  thiszone;       /* GMT to local correction */
+        uint32_t sigfigs;        /* accuracy of timestamps */
+        uint32_t snaplen;        /* max length of captured packets, in octets */
+        uint32_t network;        /* data link type */
+} pcap_hdr_t ;
+
+typedef struct  _packed_ pcaprec_hdr_s {
+        uint32_t ts_sec;         /* timestamp seconds */
+        uint32_t ts_usec;        /* timestamp microseconds */
+        uint32_t incl_len;       /* number of octets of packet saved in file */
+        uint32_t orig_len;       /* actual length of packet */
+} pcaprec_hdr_t;
+
+int bus_pcap_header(size_t snaplen, FILE *f) {
+
+        pcap_hdr_t hdr = {
+                .magic_number = 0xa1b2c3d4U,
+                .version_major = 2,
+                .version_minor = 4,
+                .thiszone = 0, /* UTC */
+                .sigfigs = 0,
+                .network = 231, /* D-Bus */
+        };
+
+        if (!f)
+                f = stdout;
+
+        assert(snaplen > 0);
+        assert((size_t) (uint32_t) snaplen == snaplen);
+
+        hdr.snaplen = (uint32_t) snaplen;
+
+        fwrite(&hdr, 1, sizeof(hdr), f);
+
+        return fflush_and_check(f);
+}
+
+int bus_message_pcap_frame(sd_bus_message *m, size_t snaplen, FILE *f) {
+        struct bus_body_part *part;
+        pcaprec_hdr_t hdr = {};
+        struct timeval tv;
+        unsigned i;
+        size_t w;
+
+        if (!f)
+                f = stdout;
+
+        assert(m);
+        assert(snaplen > 0);
+        assert((size_t) (uint32_t) snaplen == snaplen);
+
+        if (m->realtime != 0)
+                timeval_store(&tv, m->realtime);
+        else
+                assert_se(gettimeofday(&tv, NULL) >= 0);
+
+        hdr.ts_sec = tv.tv_sec;
+        hdr.ts_usec = tv.tv_usec;
+        hdr.orig_len = BUS_MESSAGE_SIZE(m);
+        hdr.incl_len = MIN(hdr.orig_len, snaplen);
+
+        /* write the pcap header */
+        fwrite(&hdr, 1, sizeof(hdr), f);
+
+        /* write the dbus header */
+        w = MIN(BUS_MESSAGE_BODY_BEGIN(m), snaplen);
+        fwrite(m->header, 1, w, f);
+        snaplen -= w;
+
+        /* write the dbus body */
+        MESSAGE_FOREACH_PART(part, i, m) {
+                if (snaplen <= 0)
+                        break;
+
+                w = MIN(part->size, snaplen);
+                fwrite(part->data, 1, w, f);
+                snaplen -= w;
+        }
+
+        return fflush_and_check(f);
+}
diff --git a/src/libsystemd/sd-bus/bus-dump.h b/src/libsystemd/sd-bus/bus-dump.h
new file mode 100644
index 0000000..aeb4616
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-dump.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "sd-bus.h"
+
+int bus_creds_dump(sd_bus_creds *c, FILE *f, bool terse);
+
+int bus_pcap_header(size_t snaplen, FILE *f);
+int bus_message_pcap_frame(sd_bus_message *m, size_t snaplen, FILE *f);
diff --git a/src/libsystemd/sd-bus/bus-error.c b/src/libsystemd/sd-bus/bus-error.c
new file mode 100644
index 0000000..8da2024
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-error.c
@@ -0,0 +1,615 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-error.h"
+#include "errno-list.h"
+#include "errno-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
+
+BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_standard_errors[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.Failed",                           EACCES),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoMemory",                         ENOMEM),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.ServiceUnknown",                   EHOSTUNREACH),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NameHasNoOwner",                   ENXIO),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoReply",                          ETIMEDOUT),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.IOError",                          EIO),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.BadAddress",                       EADDRNOTAVAIL),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NotSupported",                     EOPNOTSUPP),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.LimitsExceeded",                   ENOBUFS),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.AccessDenied",                     EACCES),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.AuthFailed",                       EACCES),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InteractiveAuthorizationRequired", EACCES),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoServer",                         EHOSTDOWN),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.Timeout",                          ETIMEDOUT),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoNetwork",                        ENONET),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.AddressInUse",                     EADDRINUSE),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.Disconnected",                     ECONNRESET),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InvalidArgs",                      EINVAL),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.FileNotFound",                     ENOENT),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.FileExists",                       EEXIST),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownMethod",                    EBADR),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownObject",                    EBADR),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownInterface",                 EBADR),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownProperty",                  EBADR),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.PropertyReadOnly",                 EROFS),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnixProcessIdUnknown",             ESRCH),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InvalidSignature",                 EINVAL),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InconsistentMessage",              EBADMSG),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.TimedOut",                         ETIMEDOUT),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.MatchRuleInvalid",                 EINVAL),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InvalidFileContent",               EINVAL),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.MatchRuleNotFound",                ENOENT),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.SELinuxSecurityContextUnknown",    ESRCH),
+        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.ObjectPathInUse",                  EBUSY),
+        SD_BUS_ERROR_MAP_END
+};
+
+/* GCC maps this magically to the beginning and end of the BUS_ERROR_MAP section */
+extern const sd_bus_error_map __start_SYSTEMD_BUS_ERROR_MAP[];
+extern const sd_bus_error_map __stop_SYSTEMD_BUS_ERROR_MAP[];
+
+/* Additional maps registered with sd_bus_error_add_map() are in this
+ * NULL terminated array */
+static const sd_bus_error_map **additional_error_maps = NULL;
+
+static int bus_error_name_to_errno(const char *name) {
+        const sd_bus_error_map **map, *m;
+        const char *p;
+        int r;
+
+        if (!name)
+                return EINVAL;
+
+        p = startswith(name, "System.Error.");
+        if (p) {
+                r = errno_from_name(p);
+                if (r < 0)
+                        return EIO;
+
+                return r;
+        }
+
+        if (additional_error_maps)
+                for (map = additional_error_maps; *map; map++)
+                        for (m = *map;; m++) {
+                                /* For additional error maps the end marker is actually the end marker */
+                                if (m->code == BUS_ERROR_MAP_END_MARKER)
+                                        break;
+
+                                if (streq(m->name, name))
+                                        return m->code;
+                        }
+
+        m = ALIGN_TO_PTR(__start_SYSTEMD_BUS_ERROR_MAP, sizeof(void*));
+        while (m < __stop_SYSTEMD_BUS_ERROR_MAP) {
+                /* For magic ELF error maps, the end marker might
+                 * appear in the middle of things, since multiple maps
+                 * might appear in the same section. Hence, let's skip
+                 * over it, but realign the pointer to the next 8 byte
+                 * boundary, which is the selected alignment for the
+                 * arrays. */
+                if (m->code == BUS_ERROR_MAP_END_MARKER) {
+                        m = ALIGN_TO_PTR(m + 1, sizeof(void*));
+                        continue;
+                }
+
+                if (streq(m->name, name))
+                        return m->code;
+
+                m++;
+        }
+
+        return EIO;
+}
+
+static sd_bus_error errno_to_bus_error_const(int error) {
+
+        if (error < 0)
+                error = -error;
+
+        switch (error) {
+
+        case ENOMEM:
+                return BUS_ERROR_OOM;
+
+        case EPERM:
+        case EACCES:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_ACCESS_DENIED, "Access denied");
+
+        case EINVAL:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INVALID_ARGS, "Invalid argument");
+
+        case ESRCH:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_UNIX_PROCESS_ID_UNKNOWN, "No such process");
+
+        case ENOENT:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_FILE_NOT_FOUND, "File not found");
+
+        case EEXIST:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_FILE_EXISTS, "File exists");
+
+        case ETIMEDOUT:
+        case ETIME:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_TIMEOUT, "Timed out");
+
+        case EIO:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_IO_ERROR, "Input/output error");
+
+        case ENETRESET:
+        case ECONNABORTED:
+        case ECONNRESET:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_DISCONNECTED, "Disconnected");
+
+        case EOPNOTSUPP:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NOT_SUPPORTED, "Not supported");
+
+        case EADDRNOTAVAIL:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_BAD_ADDRESS, "Address not available");
+
+        case ENOBUFS:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_LIMITS_EXCEEDED, "Limits exceeded");
+
+        case EADDRINUSE:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_ADDRESS_IN_USE, "Address in use");
+
+        case EBADMSG:
+                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Inconsistent message");
+        }
+
+        return SD_BUS_ERROR_NULL;
+}
+
+static int errno_to_bus_error_name_new(int error, char **ret) {
+        const char *name;
+        char *n;
+
+        if (error < 0)
+                error = -error;
+
+        name = errno_to_name(error);
+        if (!name)
+                return 0;
+
+        n = strjoin("System.Error.", name);
+        if (!n)
+                return -ENOMEM;
+
+        *ret = n;
+        return 1;
+}
+
+bool bus_error_is_dirty(sd_bus_error *e) {
+        if (!e)
+                return false;
+
+        return e->name || e->message || e->_need_free != 0;
+}
+
+_public_ void sd_bus_error_free(sd_bus_error *e) {
+        if (!e)
+                return;
+
+        if (e->_need_free > 0) {
+                free((void*) e->name);
+                free((void*) e->message);
+        }
+
+        *e = SD_BUS_ERROR_NULL;
+}
+
+_public_ int sd_bus_error_set(sd_bus_error *e, const char *name, const char *message) {
+
+        if (!name)
+                return 0;
+        if (!e)
+                goto finish;
+
+        assert_return(!bus_error_is_dirty(e), -EINVAL);
+
+        e->name = strdup(name);
+        if (!e->name) {
+                *e = BUS_ERROR_OOM;
+                return -ENOMEM;
+        }
+
+        if (message)
+                e->message = strdup(message);
+
+        e->_need_free = 1;
+
+finish:
+        return -bus_error_name_to_errno(name);
+}
+
+int bus_error_setfv(sd_bus_error *e, const char *name, const char *format, va_list ap) {
+
+        if (!name)
+                return 0;
+
+        if (e) {
+                assert_return(!bus_error_is_dirty(e), -EINVAL);
+
+                e->name = strdup(name);
+                if (!e->name) {
+                        *e = BUS_ERROR_OOM;
+                        return -ENOMEM;
+                }
+
+                /* If we hit OOM on formatting the pretty message, we ignore
+                 * this, since we at least managed to write the error name */
+                if (format)
+                        (void) vasprintf((char**) &e->message, format, ap);
+
+                e->_need_free = 1;
+        }
+
+        return -bus_error_name_to_errno(name);
+}
+
+_public_ int sd_bus_error_setf(sd_bus_error *e, const char *name, const char *format, ...) {
+
+        if (format) {
+                int r;
+                va_list ap;
+
+                va_start(ap, format);
+                r = bus_error_setfv(e, name, format, ap);
+                va_end(ap);
+
+                return r;
+        }
+
+        return sd_bus_error_set(e, name, NULL);
+}
+
+_public_ int sd_bus_error_copy(sd_bus_error *dest, const sd_bus_error *e) {
+
+        if (!sd_bus_error_is_set(e))
+                return 0;
+        if (!dest)
+                goto finish;
+
+        assert_return(!bus_error_is_dirty(dest), -EINVAL);
+
+        /*
+         * _need_free  < 0 indicates that the error is temporarily const, needs deep copying
+         * _need_free == 0 indicates that the error is perpetually const, needs no deep copying
+         * _need_free  > 0 indicates that the error is fully dynamic, needs deep copying
+         */
+
+        if (e->_need_free == 0)
+                *dest = *e;
+        else {
+                dest->name = strdup(e->name);
+                if (!dest->name) {
+                        *dest = BUS_ERROR_OOM;
+                        return -ENOMEM;
+                }
+
+                if (e->message)
+                        dest->message = strdup(e->message);
+
+                dest->_need_free = 1;
+        }
+
+finish:
+        return -bus_error_name_to_errno(e->name);
+}
+
+_public_ int sd_bus_error_move(sd_bus_error *dest, sd_bus_error *e) {
+        int r;
+
+        if (!sd_bus_error_is_set(e)) {
+
+                if (dest)
+                        *dest = SD_BUS_ERROR_NULL;
+
+                return 0;
+        }
+
+        r = -bus_error_name_to_errno(e->name);
+
+        if (dest) {
+                *dest = *e;
+                *e = SD_BUS_ERROR_NULL;
+        } else
+                sd_bus_error_free(e);
+
+        return r;
+}
+
+_public_ int sd_bus_error_set_const(sd_bus_error *e, const char *name, const char *message) {
+        if (!name)
+                return 0;
+        if (!e)
+                goto finish;
+
+        assert_return(!bus_error_is_dirty(e), -EINVAL);
+
+        *e = SD_BUS_ERROR_MAKE_CONST(name, message);
+
+finish:
+        return -bus_error_name_to_errno(name);
+}
+
+_public_ int sd_bus_error_is_set(const sd_bus_error *e) {
+        if (!e)
+                return 0;
+
+        return !!e->name;
+}
+
+_public_ int sd_bus_error_has_name(const sd_bus_error *e, const char *name) {
+        if (!e)
+                return 0;
+
+        return streq_ptr(e->name, name);
+}
+
+_public_ int sd_bus_error_has_names_sentinel(const sd_bus_error *e, ...) {
+        if (!e || !e->name)
+                return 0;
+
+        va_list ap;
+        const char *p;
+
+        va_start(ap, e);
+        while ((p = va_arg(ap, const char *)))
+                if (streq(p, e->name))
+                        break;
+        va_end(ap);
+        return !!p;
+}
+
+_public_ int sd_bus_error_get_errno(const sd_bus_error* e) {
+        if (!e || !e->name)
+                return 0;
+
+        return bus_error_name_to_errno(e->name);
+}
+
+static void bus_error_strerror(sd_bus_error *e, int error) {
+        size_t k = 64;
+        char *m;
+
+        assert(e);
+
+        for (;;) {
+                char *x;
+
+                m = new(char, k);
+                if (!m)
+                        return;
+
+                errno = 0;
+                x = strerror_r(error, m, k);
+                if (errno == ERANGE || strlen(x) >= k - 1) {
+                        free(m);
+                        k *= 2;
+                        continue;
+                }
+
+                if (errno) {
+                        free(m);
+                        return;
+                }
+
+                if (x == m) {
+                        if (e->_need_free > 0) {
+                                /* Error is already dynamic, let's just update the message */
+                                free((char*) e->message);
+                                e->message = x;
+
+                        } else {
+                                char *t;
+                                /* Error was const so far, let's make it dynamic, if we can */
+
+                                t = strdup(e->name);
+                                if (!t) {
+                                        free(m);
+                                        return;
+                                }
+
+                                e->_need_free = 1;
+                                e->name = t;
+                                e->message = x;
+                        }
+                } else {
+                        free(m);
+
+                        if (e->_need_free > 0) {
+                                char *t;
+
+                                /* Error is dynamic, let's hence make the message also dynamic */
+                                t = strdup(x);
+                                if (!t)
+                                        return;
+
+                                free((char*) e->message);
+                                e->message = t;
+                        } else {
+                                /* Error is const, hence we can just override */
+                                e->message = x;
+                        }
+                }
+
+                return;
+        }
+}
+
+_public_ int sd_bus_error_set_errno(sd_bus_error *e, int error) {
+
+        if (error < 0)
+                error = -error;
+
+        if (!e)
+                return -error;
+        if (error == 0)
+                return -error;
+
+        assert_return(!bus_error_is_dirty(e), -EINVAL);
+
+        /* First, try a const translation */
+        *e = errno_to_bus_error_const(error);
+
+        if (!sd_bus_error_is_set(e)) {
+                int k;
+
+                /* If that didn't work, try a dynamic one. */
+
+                k = errno_to_bus_error_name_new(error, (char**) &e->name);
+                if (k > 0)
+                        e->_need_free = 1;
+                else if (k < 0) {
+                        *e = BUS_ERROR_OOM;
+                        return -error;
+                } else
+                        *e = BUS_ERROR_FAILED;
+        }
+
+        /* Now, fill in the message from strerror() if we can */
+        bus_error_strerror(e, error);
+        return -error;
+}
+
+_public_ int sd_bus_error_set_errnofv(sd_bus_error *e, int error, const char *format, va_list ap) {
+        PROTECT_ERRNO;
+
+        if (error < 0)
+                error = -error;
+
+        if (!e)
+                return -error;
+        if (error == 0)
+                return 0;
+
+        assert_return(!bus_error_is_dirty(e), -EINVAL);
+
+        /* First, try a const translation */
+        *e = errno_to_bus_error_const(error);
+
+        if (!sd_bus_error_is_set(e)) {
+                int k;
+
+                /* If that didn't work, try a dynamic one */
+
+                k = errno_to_bus_error_name_new(error, (char**) &e->name);
+                if (k > 0)
+                        e->_need_free = 1;
+                else if (k < 0) {
+                        *e = BUS_ERROR_OOM;
+                        return -ENOMEM;
+                } else
+                        *e = BUS_ERROR_FAILED;
+        }
+
+        if (format) {
+                _cleanup_free_ char *m = NULL;
+
+                /* Then, let's try to fill in the supplied message */
+
+                errno = error; /* Make sure that %m resolves to the specified error */
+                if (vasprintf(&m, format, ap) < 0)
+                        goto fail;
+
+                if (e->_need_free <= 0) {
+                        char *t;
+
+                        t = strdup(e->name);
+                        if (!t)
+                                goto fail;
+
+                        e->_need_free = 1;
+                        e->name = t;
+                }
+
+                e->message = TAKE_PTR(m);
+                return -error;
+        }
+
+fail:
+        /* If that didn't work, use strerror() for the message */
+        bus_error_strerror(e, error);
+        return -error;
+}
+
+_public_ int sd_bus_error_set_errnof(sd_bus_error *e, int error, const char *format, ...) {
+        int r;
+
+        if (error < 0)
+                error = -error;
+
+        if (!e)
+                return -error;
+        if (error == 0)
+                return 0;
+
+        assert_return(!bus_error_is_dirty(e), -EINVAL);
+
+        if (format) {
+                va_list ap;
+
+                va_start(ap, format);
+                r = sd_bus_error_set_errnofv(e, error, format, ap);
+                va_end(ap);
+
+                return r;
+        }
+
+        return sd_bus_error_set_errno(e, error);
+}
+
+const char *bus_error_message(const sd_bus_error *e, int error) {
+
+        if (e) {
+                /* Sometimes, the D-Bus server is a little bit too verbose with
+                 * its error messages, so let's override them here */
+                if (sd_bus_error_has_name(e, SD_BUS_ERROR_ACCESS_DENIED))
+                        return "Access denied";
+
+                if (e->message)
+                        return e->message;
+        }
+
+        return strerror_safe(error);
+}
+
+static bool map_ok(const sd_bus_error_map *map) {
+        for (; map->code != BUS_ERROR_MAP_END_MARKER; map++)
+                if (!map->name || map->code <=0)
+                        return false;
+        return true;
+}
+
+_public_ int sd_bus_error_add_map(const sd_bus_error_map *map) {
+        const sd_bus_error_map **maps = NULL;
+        unsigned n = 0;
+
+        assert_return(map, -EINVAL);
+        assert_return(map_ok(map), -EINVAL);
+
+        if (additional_error_maps)
+                for (; additional_error_maps[n] != NULL; n++)
+                        if (additional_error_maps[n] == map)
+                                return 0;
+
+        maps = reallocarray(additional_error_maps, n + 2, sizeof(struct sd_bus_error_map*));
+        if (!maps)
+                return -ENOMEM;
+
+        maps[n] = map;
+        maps[n+1] = NULL;
+
+        additional_error_maps = maps;
+        return 1;
+}
diff --git a/src/libsystemd/sd-bus/bus-error.h b/src/libsystemd/sd-bus/bus-error.h
new file mode 100644
index 0000000..557284f
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-error.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+#include "sd-bus.h"
+
+#include "macro.h"
+
+bool bus_error_is_dirty(sd_bus_error *e);
+
+const char *bus_error_message(const sd_bus_error *e, int error);
+
+int bus_error_setfv(sd_bus_error *e, const char *name, const char *format, va_list ap) _printf_(3,0);
+int bus_error_set_errnofv(sd_bus_error *e, int error, const char *format, va_list ap) _printf_(3,0);
+
+#define BUS_ERROR_OOM SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_MEMORY, "Out of memory")
+#define BUS_ERROR_FAILED SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_FAILED, "Operation failed")
+
+/*
+ * There are two ways to register error maps with the error translation
+ * logic: by using BUS_ERROR_MAP_ELF_REGISTER, which however only
+ * works when linked into the same ELF module, or via
+ * sd_bus_error_add_map() which is the official, external API, that
+ * works from any module.
+ *
+ * Note that BUS_ERROR_MAP_ELF_REGISTER has to be used as decorator in
+ * the bus error table, and BUS_ERROR_MAP_ELF_USE has to be used at
+ * least once per compilation unit (i.e. per library), to ensure that
+ * the error map is really added to the final binary.
+ */
+
+#define BUS_ERROR_MAP_ELF_REGISTER                                      \
+        _section_("SYSTEMD_BUS_ERROR_MAP")                              \
+        _used_                                                          \
+        _alignptr_                                                      \
+        _variable_no_sanitize_address_
+
+#define BUS_ERROR_MAP_ELF_USE(errors)                                   \
+        extern const sd_bus_error_map errors[];                         \
+        _used_                                                          \
+        static const sd_bus_error_map * const CONCATENATE(errors ## _copy_, __COUNTER__) = errors;
+
+/* We use something exotic as end marker, to ensure people build the
+ * maps using the macsd-ros. */
+#define BUS_ERROR_MAP_END_MARKER -'x'
+
+BUS_ERROR_MAP_ELF_USE(bus_standard_errors);
diff --git a/src/libsystemd/sd-bus/bus-gvariant.c b/src/libsystemd/sd-bus/bus-gvariant.c
new file mode 100644
index 0000000..850540a
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-gvariant.c
@@ -0,0 +1,299 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <string.h>
+
+#include "sd-bus.h"
+
+#include "bus-gvariant.h"
+#include "bus-signature.h"
+#include "bus-type.h"
+
+int bus_gvariant_get_size(const char *signature) {
+        const char *p;
+        int sum = 0, r;
+
+        /* For fixed size structs. Fails for variable size structs. */
+
+        p = signature;
+        while (*p != 0) {
+                size_t n;
+
+                r = signature_element_length(p, &n);
+                if (r < 0)
+                        return r;
+                else {
+                        char t[n+1];
+
+                        memcpy(t, p, n);
+                        t[n] = 0;
+
+                        r = bus_gvariant_get_alignment(t);
+                        if (r < 0)
+                                return r;
+
+                        sum = ALIGN_TO(sum, r);
+                }
+
+                switch (*p) {
+
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_BYTE:
+                        sum += 1;
+                        break;
+
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16:
+                        sum += 2;
+                        break;
+
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                case SD_BUS_TYPE_UNIX_FD:
+                        sum += 4;
+                        break;
+
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE:
+                        sum += 8;
+                        break;
+
+                case SD_BUS_TYPE_STRUCT_BEGIN:
+                case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                        if (n == 2) {
+                                /* unary type () has fixed size of 1 */
+                                r = 1;
+                        } else {
+                                char t[n-1];
+
+                                memcpy(t, p + 1, n - 2);
+                                t[n - 2] = 0;
+
+                                r = bus_gvariant_get_size(t);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        sum += r;
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE:
+                case SD_BUS_TYPE_ARRAY:
+                case SD_BUS_TYPE_VARIANT:
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unknown signature type");
+                }
+
+                p += n;
+        }
+
+        r = bus_gvariant_get_alignment(signature);
+        if (r < 0)
+                return r;
+
+        return ALIGN_TO(sum, r);
+}
+
+int bus_gvariant_get_alignment(const char *signature) {
+        size_t alignment = 1;
+        const char *p;
+        int r;
+
+        p = signature;
+        while (*p != 0 && alignment < 8) {
+                size_t n;
+                int a;
+
+                r = signature_element_length(p, &n);
+                if (r < 0)
+                        return r;
+
+                switch (*p) {
+
+                case SD_BUS_TYPE_BYTE:
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE:
+                        a = 1;
+                        break;
+
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16:
+                        a = 2;
+                        break;
+
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                case SD_BUS_TYPE_UNIX_FD:
+                        a = 4;
+                        break;
+
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE:
+                case SD_BUS_TYPE_VARIANT:
+                        a = 8;
+                        break;
+
+                case SD_BUS_TYPE_ARRAY: {
+                        char t[n];
+
+                        memcpy(t, p + 1, n - 1);
+                        t[n - 1] = 0;
+
+                        a = bus_gvariant_get_alignment(t);
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRUCT_BEGIN:
+                case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                        char t[n-1];
+
+                        memcpy(t, p + 1, n - 2);
+                        t[n - 2] = 0;
+
+                        a = bus_gvariant_get_alignment(t);
+                        break;
+                }
+
+                default:
+                        assert_not_reached("Unknown signature type");
+                }
+
+                if (a < 0)
+                        return a;
+
+                assert(a > 0 && a <= 8);
+                if ((size_t) a > alignment)
+                        alignment = (size_t) a;
+
+                p += n;
+        }
+
+        return alignment;
+}
+
+int bus_gvariant_is_fixed_size(const char *signature) {
+        const char *p;
+        int r;
+
+        assert(signature);
+
+        p = signature;
+        while (*p != 0) {
+                size_t n;
+
+                r = signature_element_length(p, &n);
+                if (r < 0)
+                        return r;
+
+                switch (*p) {
+
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE:
+                case SD_BUS_TYPE_ARRAY:
+                case SD_BUS_TYPE_VARIANT:
+                        return 0;
+
+                case SD_BUS_TYPE_BYTE:
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16:
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                case SD_BUS_TYPE_UNIX_FD:
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE:
+                        break;
+
+                case SD_BUS_TYPE_STRUCT_BEGIN:
+                case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                        char t[n-1];
+
+                        memcpy(t, p + 1, n - 2);
+                        t[n - 2] = 0;
+
+                        r = bus_gvariant_is_fixed_size(t);
+                        if (r <= 0)
+                                return r;
+                        break;
+                }
+
+                default:
+                        assert_not_reached("Unknown signature type");
+                }
+
+                p += n;
+        }
+
+        return true;
+}
+
+size_t bus_gvariant_determine_word_size(size_t sz, size_t extra) {
+        if (sz + extra <= 0xFF)
+                return 1;
+        else if (sz + extra*2 <= 0xFFFF)
+                return 2;
+        else if (sz + extra*4 <= 0xFFFFFFFF)
+                return 4;
+        else
+                return 8;
+}
+
+size_t bus_gvariant_read_word_le(void *p, size_t sz) {
+        union {
+                uint16_t u16;
+                uint32_t u32;
+                uint64_t u64;
+        } x;
+
+        assert(p);
+
+        if (sz == 1)
+                return *(uint8_t*) p;
+
+        memcpy(&x, p, sz);
+
+        if (sz == 2)
+                return le16toh(x.u16);
+        else if (sz == 4)
+                return le32toh(x.u32);
+        else if (sz == 8)
+                return le64toh(x.u64);
+
+        assert_not_reached("unknown word width");
+}
+
+void bus_gvariant_write_word_le(void *p, size_t sz, size_t value) {
+        union {
+                uint16_t u16;
+                uint32_t u32;
+                uint64_t u64;
+        } x;
+
+        assert(p);
+        assert(sz == 8 || (value < (1ULL << (sz*8))));
+
+        if (sz == 1) {
+                *(uint8_t*) p = value;
+                return;
+        } else if (sz == 2)
+                x.u16 = htole16((uint16_t) value);
+        else if (sz == 4)
+                x.u32 = htole32((uint32_t) value);
+        else if (sz == 8)
+                x.u64 = htole64((uint64_t) value);
+        else
+                assert_not_reached("unknown word width");
+
+        memcpy(p, &x, sz);
+}
diff --git a/src/libsystemd/sd-bus/bus-gvariant.h b/src/libsystemd/sd-bus/bus-gvariant.h
new file mode 100644
index 0000000..213fa97
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-gvariant.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "macro.h"
+
+int bus_gvariant_get_size(const char *signature) _pure_;
+int bus_gvariant_get_alignment(const char *signature) _pure_;
+int bus_gvariant_is_fixed_size(const char *signature) _pure_;
+
+size_t bus_gvariant_determine_word_size(size_t sz, size_t extra);
+void bus_gvariant_write_word_le(void *p, size_t sz, size_t value);
+size_t bus_gvariant_read_word_le(void *p, size_t sz);
diff --git a/src/libsystemd/sd-bus/bus-internal.c b/src/libsystemd/sd-bus/bus-internal.c
new file mode 100644
index 0000000..3f03ad7
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-internal.c
@@ -0,0 +1,338 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "hexdecoct.h"
+#include "string-util.h"
+
+bool object_path_is_valid(const char *p) {
+        const char *q;
+        bool slash;
+
+        if (!p)
+                return false;
+
+        if (p[0] != '/')
+                return false;
+
+        if (p[1] == 0)
+                return true;
+
+        for (slash = true, q = p+1; *q; q++)
+                if (*q == '/') {
+                        if (slash)
+                                return false;
+
+                        slash = true;
+                } else {
+                        bool good;
+
+                        good =
+                                (*q >= 'a' && *q <= 'z') ||
+                                (*q >= 'A' && *q <= 'Z') ||
+                                (*q >= '0' && *q <= '9') ||
+                                *q == '_';
+
+                        if (!good)
+                                return false;
+
+                        slash = false;
+                }
+
+        if (slash)
+                return false;
+
+        return (q - p) <= BUS_PATH_SIZE_MAX;
+}
+
+char* object_path_startswith(const char *a, const char *b) {
+        const char *p;
+
+        if (!object_path_is_valid(a) ||
+            !object_path_is_valid(b))
+                return NULL;
+
+        if (streq(b, "/"))
+                return (char*) a + 1;
+
+        p = startswith(a, b);
+        if (!p)
+                return NULL;
+
+        if (*p == 0)
+                return (char*) p;
+
+        if (*p == '/')
+                return (char*) p + 1;
+
+        return NULL;
+}
+
+bool interface_name_is_valid(const char *p) {
+        const char *q;
+        bool dot, found_dot = false;
+
+        if (isempty(p))
+                return false;
+
+        for (dot = true, q = p; *q; q++)
+                if (*q == '.') {
+                        if (dot)
+                                return false;
+
+                        found_dot = dot = true;
+                } else {
+                        bool good;
+
+                        good =
+                                (*q >= 'a' && *q <= 'z') ||
+                                (*q >= 'A' && *q <= 'Z') ||
+                                (!dot && *q >= '0' && *q <= '9') ||
+                                *q == '_';
+
+                        if (!good)
+                                return false;
+
+                        dot = false;
+                }
+
+        if (q - p > SD_BUS_MAXIMUM_NAME_LENGTH)
+                return false;
+
+        if (dot)
+                return false;
+
+        if (!found_dot)
+                return false;
+
+        return true;
+}
+
+bool service_name_is_valid(const char *p) {
+        const char *q;
+        bool dot, found_dot = false, unique;
+
+        if (isempty(p))
+                return false;
+
+        unique = p[0] == ':';
+
+        for (dot = true, q = unique ? p+1 : p; *q; q++)
+                if (*q == '.') {
+                        if (dot)
+                                return false;
+
+                        found_dot = dot = true;
+                } else {
+                        bool good;
+
+                        good =
+                                (*q >= 'a' && *q <= 'z') ||
+                                (*q >= 'A' && *q <= 'Z') ||
+                                ((!dot || unique) && *q >= '0' && *q <= '9') ||
+                                IN_SET(*q, '_', '-');
+
+                        if (!good)
+                                return false;
+
+                        dot = false;
+                }
+
+        if (q - p > SD_BUS_MAXIMUM_NAME_LENGTH)
+                return false;
+
+        if (dot)
+                return false;
+
+        if (!found_dot)
+                return false;
+
+        return true;
+}
+
+bool member_name_is_valid(const char *p) {
+        const char *q;
+
+        if (isempty(p))
+                return false;
+
+        for (q = p; *q; q++) {
+                bool good;
+
+                good =
+                        (*q >= 'a' && *q <= 'z') ||
+                        (*q >= 'A' && *q <= 'Z') ||
+                        (*q >= '0' && *q <= '9') ||
+                        *q == '_';
+
+                if (!good)
+                        return false;
+        }
+
+        if (q - p > SD_BUS_MAXIMUM_NAME_LENGTH)
+                return false;
+
+        return true;
+}
+
+/*
+ * Complex pattern match
+ * This checks whether @a is a 'complex-prefix' of @b, or @b is a
+ * 'complex-prefix' of @a, based on strings that consist of labels with @c as
+ * separator. This function returns true if:
+ *   - both strings are equal
+ *   - either is a prefix of the other and ends with @c
+ * The second rule makes sure that either string needs to be fully included in
+ * the other, and the string which is considered the prefix needs to end with a
+ * separator.
+ */
+static bool complex_pattern_check(char c, const char *a, const char *b) {
+        bool separator = false;
+
+        if (!a && !b)
+                return true;
+
+        if (!a || !b)
+                return false;
+
+        for (;;) {
+                if (*a != *b)
+                        return (separator && (*a == 0 || *b == 0));
+
+                if (*a == 0)
+                        return true;
+
+                separator = *a == c;
+
+                a++, b++;
+        }
+}
+
+bool namespace_complex_pattern(const char *pattern, const char *value) {
+        return complex_pattern_check('.', pattern, value);
+}
+
+bool path_complex_pattern(const char *pattern, const char *value) {
+        return complex_pattern_check('/', pattern, value);
+}
+
+/*
+ * Simple pattern match
+ * This checks whether @a is a 'simple-prefix' of @b, based on strings that
+ * consist of labels with @c as separator. This function returns true, if:
+ *   - if @a and @b are equal
+ *   - if @a is a prefix of @b, and the first following character in @b (or the
+ *     last character in @a) is @c
+ * The second rule basically makes sure that if @a is a prefix of @b, then @b
+ * must follow with a new label separated by @c. It cannot extend the label.
+ */
+static bool simple_pattern_check(char c, const char *a, const char *b) {
+        bool separator = false;
+
+        if (!a && !b)
+                return true;
+
+        if (!a || !b)
+                return false;
+
+        for (;;) {
+                if (*a != *b)
+                        return *a == 0 && (*b == c || separator);
+
+                if (*a == 0)
+                        return true;
+
+                separator = *a == c;
+
+                a++, b++;
+        }
+}
+
+bool namespace_simple_pattern(const char *pattern, const char *value) {
+        return simple_pattern_check('.', pattern, value);
+}
+
+bool path_simple_pattern(const char *pattern, const char *value) {
+        return simple_pattern_check('/', pattern, value);
+}
+
+int bus_message_type_from_string(const char *s, uint8_t *u) {
+        if (streq(s, "signal"))
+                *u = SD_BUS_MESSAGE_SIGNAL;
+        else if (streq(s, "method_call"))
+                *u = SD_BUS_MESSAGE_METHOD_CALL;
+        else if (streq(s, "error"))
+                *u = SD_BUS_MESSAGE_METHOD_ERROR;
+        else if (streq(s, "method_return"))
+                *u = SD_BUS_MESSAGE_METHOD_RETURN;
+        else
+                return -EINVAL;
+
+        return 0;
+}
+
+const char *bus_message_type_to_string(uint8_t u) {
+        if (u == SD_BUS_MESSAGE_SIGNAL)
+                return "signal";
+        else if (u == SD_BUS_MESSAGE_METHOD_CALL)
+                return "method_call";
+        else if (u == SD_BUS_MESSAGE_METHOD_ERROR)
+                return "error";
+        else if (u == SD_BUS_MESSAGE_METHOD_RETURN)
+                 return "method_return";
+        else
+                return NULL;
+}
+
+char *bus_address_escape(const char *v) {
+        const char *a;
+        char *r, *b;
+
+        r = new(char, strlen(v)*3+1);
+        if (!r)
+                return NULL;
+
+        for (a = v, b = r; *a; a++) {
+
+                if ((*a >= '0' && *a <= '9') ||
+                    (*a >= 'a' && *a <= 'z') ||
+                    (*a >= 'A' && *a <= 'Z') ||
+                    strchr("_-/.", *a))
+                        *(b++) = *a;
+                else {
+                        *(b++) = '%';
+                        *(b++) = hexchar(*a >> 4);
+                        *(b++) = hexchar(*a & 0xF);
+                }
+        }
+
+        *b = 0;
+        return r;
+}
+
+int bus_maybe_reply_error(sd_bus_message *m, int r, sd_bus_error *error) {
+        assert(m);
+
+        if (sd_bus_error_is_set(error) || r < 0) {
+                if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL)
+                        sd_bus_reply_method_errno(m, r, error);
+        } else
+                return r;
+
+        log_debug("Failed to process message type=%s sender=%s destination=%s path=%s interface=%s member=%s cookie=%" PRIu64 " reply_cookie=%" PRIu64 " signature=%s error-name=%s error-message=%s: %s",
+                  bus_message_type_to_string(m->header->type),
+                  strna(sd_bus_message_get_sender(m)),
+                  strna(sd_bus_message_get_destination(m)),
+                  strna(sd_bus_message_get_path(m)),
+                  strna(sd_bus_message_get_interface(m)),
+                  strna(sd_bus_message_get_member(m)),
+                  BUS_MESSAGE_COOKIE(m),
+                  m->reply_cookie,
+                  strna(m->root_container.signature),
+                  strna(m->error.name),
+                  strna(m->error.message),
+                  bus_error_message(error, r));
+
+        return 1;
+}
diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
new file mode 100644
index 0000000..233a228
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -0,0 +1,416 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <pthread.h>
+
+#include "sd-bus.h"
+
+#include "bus-error.h"
+#include "bus-kernel.h"
+#include "bus-match.h"
+#include "def.h"
+#include "hashmap.h"
+#include "list.h"
+#include "prioq.h"
+#include "socket-util.h"
+#include "time-util.h"
+
+/* Note that we use the new /run prefix here (instead of /var/run) since we require them to be aliases and
+ * that way we become independent of /var being mounted */
+#define DEFAULT_SYSTEM_BUS_ADDRESS "unix:path=/run/dbus/system_bus_socket"
+#define DEFAULT_USER_BUS_ADDRESS_FMT "unix:path=%s/bus"
+
+struct reply_callback {
+        sd_bus_message_handler_t callback;
+        usec_t timeout_usec; /* this is a relative timeout until we reach the BUS_HELLO state, and an absolute one right after */
+        uint64_t cookie;
+        unsigned prioq_idx;
+};
+
+struct filter_callback {
+        sd_bus_message_handler_t callback;
+
+        unsigned last_iteration;
+
+        LIST_FIELDS(struct filter_callback, callbacks);
+};
+
+struct match_callback {
+        sd_bus_message_handler_t callback;
+        sd_bus_message_handler_t install_callback;
+
+        sd_bus_slot *install_slot; /* The AddMatch() call */
+
+        unsigned last_iteration;
+
+        /* Don't dispatch this slot with messages that arrived in any iteration before or at the this
+         * one. We use this to ensure that matches don't apply "retroactively" and thus can confuse the
+         * caller: matches will only match incoming messages from the moment on the match was installed. */
+        uint64_t after;
+
+        char *match_string;
+
+        struct bus_match_node *match_node;
+};
+
+struct node {
+        char *path;
+        struct node *parent;
+        LIST_HEAD(struct node, child);
+        LIST_FIELDS(struct node, siblings);
+
+        LIST_HEAD(struct node_callback, callbacks);
+        LIST_HEAD(struct node_vtable, vtables);
+        LIST_HEAD(struct node_enumerator, enumerators);
+        LIST_HEAD(struct node_object_manager, object_managers);
+};
+
+struct node_callback {
+        struct node *node;
+
+        bool is_fallback:1;
+        unsigned last_iteration;
+
+        sd_bus_message_handler_t callback;
+
+        LIST_FIELDS(struct node_callback, callbacks);
+};
+
+struct node_enumerator {
+        struct node *node;
+
+        sd_bus_node_enumerator_t callback;
+
+        unsigned last_iteration;
+
+        LIST_FIELDS(struct node_enumerator, enumerators);
+};
+
+struct node_object_manager {
+        struct node *node;
+
+        LIST_FIELDS(struct node_object_manager, object_managers);
+};
+
+struct node_vtable {
+        struct node *node;
+
+        bool is_fallback:1;
+        unsigned last_iteration;
+
+        char *interface;
+        const sd_bus_vtable *vtable;
+        sd_bus_object_find_t find;
+
+        LIST_FIELDS(struct node_vtable, vtables);
+};
+
+struct vtable_member {
+        const char *path;
+        const char *interface;
+        const char *member;
+        struct node_vtable *parent;
+        unsigned last_iteration;
+        const sd_bus_vtable *vtable;
+};
+
+typedef enum BusSlotType {
+        BUS_REPLY_CALLBACK,
+        BUS_FILTER_CALLBACK,
+        BUS_MATCH_CALLBACK,
+        BUS_NODE_CALLBACK,
+        BUS_NODE_ENUMERATOR,
+        BUS_NODE_VTABLE,
+        BUS_NODE_OBJECT_MANAGER,
+        _BUS_SLOT_INVALID = -1,
+} BusSlotType;
+
+struct sd_bus_slot {
+        unsigned n_ref;
+        BusSlotType type:5;
+
+        /* Slots can be "floating" or not. If they are not floating (the usual case) then they reference the bus object
+         * they are associated with. This means the bus object stays allocated at least as long as there is a slot
+         * around associated with it. If it is floating, then the slot's lifecycle is bound to the lifecycle of the
+         * bus: it will be disconnected from the bus when the bus is destroyed, and it keeping the slot reffed hence
+         * won't mean the bus stays reffed too. Internally this means the reference direction is reversed: floating
+         * slots objects are referenced by the bus object, and not vice versa. */
+        bool floating:1;
+
+        bool match_added:1;
+
+        sd_bus *bus;
+        void *userdata;
+        sd_bus_destroy_t destroy_callback;
+
+        char *description;
+
+        LIST_FIELDS(sd_bus_slot, slots);
+
+        union {
+                struct reply_callback reply_callback;
+                struct filter_callback filter_callback;
+                struct match_callback match_callback;
+                struct node_callback node_callback;
+                struct node_enumerator node_enumerator;
+                struct node_object_manager node_object_manager;
+                struct node_vtable node_vtable;
+        };
+};
+
+enum bus_state {
+        BUS_UNSET,
+        BUS_WATCH_BIND,      /* waiting for the socket to appear via inotify */
+        BUS_OPENING,         /* the kernel's connect() is still not ready */
+        BUS_AUTHENTICATING,  /* we are currently in the "SASL" authorization phase of dbus */
+        BUS_HELLO,           /* we are waiting for the Hello() response */
+        BUS_RUNNING,
+        BUS_CLOSING,
+        BUS_CLOSED,
+        _BUS_STATE_MAX,
+};
+
+static inline bool BUS_IS_OPEN(enum bus_state state) {
+        return state > BUS_UNSET && state < BUS_CLOSING;
+}
+
+enum bus_auth {
+        _BUS_AUTH_INVALID,
+        BUS_AUTH_EXTERNAL,
+        BUS_AUTH_ANONYMOUS
+};
+
+struct sd_bus {
+        unsigned n_ref;
+
+        enum bus_state state;
+        int input_fd, output_fd;
+        int inotify_fd;
+        int message_version;
+        int message_endian;
+
+        bool can_fds:1;
+        bool bus_client:1;
+        bool ucred_valid:1;
+        bool is_server:1;
+        bool anonymous_auth:1;
+        bool prefer_readv:1;
+        bool prefer_writev:1;
+        bool match_callbacks_modified:1;
+        bool filter_callbacks_modified:1;
+        bool nodes_modified:1;
+        bool trusted:1;
+        bool manual_peer_interface:1;
+        bool is_system:1;
+        bool is_user:1;
+        bool allow_interactive_authorization:1;
+        bool exit_on_disconnect:1;
+        bool exited:1;
+        bool exit_triggered:1;
+        bool is_local:1;
+        bool watch_bind:1;
+        bool is_monitor:1;
+        bool accept_fd:1;
+        bool attach_timestamp:1;
+        bool connected_signal:1;
+        bool close_on_exit:1;
+
+        signed int use_memfd:2;
+
+        void *rbuffer;
+        size_t rbuffer_size;
+
+        sd_bus_message **rqueue;
+        size_t rqueue_size;
+        size_t rqueue_allocated;
+
+        sd_bus_message **wqueue;
+        size_t wqueue_size;
+        size_t windex;
+        size_t wqueue_allocated;
+
+        uint64_t cookie;
+        uint64_t read_counter; /* A counter for each incoming msg */
+
+        char *unique_name;
+        uint64_t unique_id;
+
+        struct bus_match_node match_callbacks;
+        Prioq *reply_callbacks_prioq;
+        OrderedHashmap *reply_callbacks;
+        LIST_HEAD(struct filter_callback, filter_callbacks);
+
+        Hashmap *nodes;
+        Hashmap *vtable_methods;
+        Hashmap *vtable_properties;
+
+        union sockaddr_union sockaddr;
+        socklen_t sockaddr_size;
+
+        pid_t nspid;
+        char *machine;
+
+        sd_id128_t server_id;
+
+        char *address;
+        unsigned address_index;
+
+        int last_connect_error;
+
+        enum bus_auth auth;
+        unsigned auth_index;
+        struct iovec auth_iovec[3];
+        size_t auth_rbegin;
+        char *auth_buffer;
+        usec_t auth_timeout;
+
+        struct ucred ucred;
+        char *label;
+        gid_t *groups;
+        size_t n_groups;
+
+        uint64_t creds_mask;
+
+        int *fds;
+        size_t n_fds;
+
+        char *exec_path;
+        char **exec_argv;
+
+        /* We do locking around the memfd cache, since we want to
+         * allow people to process a sd_bus_message in a different
+         * thread then it was generated on and free it there. Since
+         * adding something to the memfd cache might happen when a
+         * message is released, we hence need to protect this bit with
+         * a mutex. */
+        pthread_mutex_t memfd_cache_mutex;
+        struct memfd_cache memfd_cache[MEMFD_CACHE_MAX];
+        unsigned n_memfd_cache;
+
+        pid_t original_pid;
+        pid_t busexec_pid;
+
+        unsigned iteration_counter;
+
+        sd_event_source *input_io_event_source;
+        sd_event_source *output_io_event_source;
+        sd_event_source *time_event_source;
+        sd_event_source *quit_event_source;
+        sd_event_source *inotify_event_source;
+        sd_event *event;
+        int event_priority;
+
+        pid_t tid;
+
+        sd_bus_message *current_message;
+        sd_bus_slot *current_slot;
+        sd_bus_message_handler_t current_handler;
+        void *current_userdata;
+
+        sd_bus **default_bus_ptr;
+
+        char *description;
+        char *patch_sender;
+
+        sd_bus_track *track_queue;
+
+        LIST_HEAD(sd_bus_slot, slots);
+        LIST_HEAD(sd_bus_track, tracks);
+
+        int *inotify_watches;
+        size_t n_inotify_watches;
+
+        /* zero means use value specified by $SYSTEMD_BUS_TIMEOUT= environment variable or built-in default */
+        usec_t method_call_timeout;
+};
+
+/* For method calls we timeout at 25s, like in the D-Bus reference implementation */
+#define BUS_DEFAULT_TIMEOUT ((usec_t) (25 * USEC_PER_SEC))
+
+/* For the authentication phase we grant 90s, to provide extra room during boot, when RNGs and such are not filled up
+ * with enough entropy yet and might delay the boot */
+#define BUS_AUTH_TIMEOUT ((usec_t) DEFAULT_TIMEOUT_USEC)
+
+#define BUS_WQUEUE_MAX (384*1024)
+#define BUS_RQUEUE_MAX (384*1024)
+
+#define BUS_MESSAGE_SIZE_MAX (128*1024*1024)
+#define BUS_AUTH_SIZE_MAX (64*1024)
+/* Note that the D-Bus specification states that bus paths shall have no size limit. We enforce here one
+ * anyway, since truly unbounded strings are a security problem. The limit we pick is relatively large however,
+ * to not clash unnecessarily with real-life applications. */
+#define BUS_PATH_SIZE_MAX (64*1024)
+
+#define BUS_CONTAINER_DEPTH 128
+
+/* Defined by the specification as maximum size of an array in bytes */
+#define BUS_ARRAY_MAX_SIZE 67108864
+
+#define BUS_FDS_MAX 1024
+
+#define BUS_EXEC_ARGV_MAX 256
+
+bool interface_name_is_valid(const char *p) _pure_;
+bool service_name_is_valid(const char *p) _pure_;
+bool member_name_is_valid(const char *p) _pure_;
+bool object_path_is_valid(const char *p) _pure_;
+
+char *object_path_startswith(const char *a, const char *b) _pure_;
+
+bool namespace_complex_pattern(const char *pattern, const char *value) _pure_;
+bool path_complex_pattern(const char *pattern, const char *value) _pure_;
+
+bool namespace_simple_pattern(const char *pattern, const char *value) _pure_;
+bool path_simple_pattern(const char *pattern, const char *value) _pure_;
+
+int bus_message_type_from_string(const char *s, uint8_t *u) _pure_;
+const char *bus_message_type_to_string(uint8_t u) _pure_;
+
+#define error_name_is_valid interface_name_is_valid
+
+sd_bus *bus_resolve(sd_bus *bus);
+
+int bus_ensure_running(sd_bus *bus);
+int bus_start_running(sd_bus *bus);
+int bus_next_address(sd_bus *bus);
+
+int bus_seal_synthetic_message(sd_bus *b, sd_bus_message *m);
+
+int bus_rqueue_make_room(sd_bus *bus);
+
+bool bus_pid_changed(sd_bus *bus);
+
+char *bus_address_escape(const char *v);
+
+int bus_attach_io_events(sd_bus *b);
+int bus_attach_inotify_event(sd_bus *b);
+
+void bus_close_inotify_fd(sd_bus *b);
+void bus_close_io_fds(sd_bus *b);
+
+#define OBJECT_PATH_FOREACH_PREFIX(prefix, path)                        \
+        for (char *_slash = ({ strcpy((prefix), (path)); streq((prefix), "/") ? NULL : strrchr((prefix), '/'); }) ; \
+             _slash && ((_slash[(_slash) == (prefix)] = 0), true);       \
+             _slash = streq((prefix), "/") ? NULL : strrchr((prefix), '/'))
+
+/* If we are invoking callbacks of a bus object, ensure unreffing the
+ * bus from the callback doesn't destroy the object we are working on */
+#define BUS_DONT_DESTROY(bus) \
+        _cleanup_(sd_bus_unrefp) _unused_ sd_bus *_dont_destroy_##bus = sd_bus_ref(bus)
+
+int bus_set_address_system(sd_bus *bus);
+int bus_set_address_user(sd_bus *bus);
+int bus_set_address_system_remote(sd_bus *b, const char *host);
+int bus_set_address_system_machine(sd_bus *b, const char *machine);
+
+int bus_maybe_reply_error(sd_bus_message *m, int r, sd_bus_error *error);
+
+#define bus_assert_return(expr, r, error)                               \
+        do {                                                            \
+                if (!assert_log(expr, #expr))                           \
+                        return sd_bus_error_set_errno(error, r);        \
+        } while (false)
+
+void bus_enter_closing(sd_bus *bus);
+
+void bus_set_state(sd_bus *bus, enum bus_state state);
diff --git a/src/libsystemd/sd-bus/bus-introspect.c b/src/libsystemd/sd-bus/bus-introspect.c
new file mode 100644
index 0000000..866fca7
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-introspect.c
@@ -0,0 +1,285 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-internal.h"
+#include "bus-introspect.h"
+#include "bus-objects.h"
+#include "bus-protocol.h"
+#include "bus-signature.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "memory-util.h"
+#include "string-util.h"
+
+#define BUS_INTROSPECT_DOCTYPE                                       \
+        "<!DOCTYPE node PUBLIC \"-//freedesktop//DTD D-BUS Object Introspection 1.0//EN\"\n" \
+        "\"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd\">\n"
+
+#define BUS_INTROSPECT_INTERFACE_PEER                                \
+        " <interface name=\"org.freedesktop.DBus.Peer\">\n"             \
+        "  <method name=\"Ping\"/>\n"                                   \
+        "  <method name=\"GetMachineId\">\n"                            \
+        "   <arg type=\"s\" name=\"machine_uuid\" direction=\"out\"/>\n" \
+        "  </method>\n"                                                 \
+        " </interface>\n"
+
+#define BUS_INTROSPECT_INTERFACE_INTROSPECTABLE                      \
+        " <interface name=\"org.freedesktop.DBus.Introspectable\">\n"   \
+        "  <method name=\"Introspect\">\n"                              \
+        "   <arg name=\"data\" type=\"s\" direction=\"out\"/>\n"        \
+        "  </method>\n"                                                 \
+        " </interface>\n"
+
+#define BUS_INTROSPECT_INTERFACE_PROPERTIES                          \
+        " <interface name=\"org.freedesktop.DBus.Properties\">\n"       \
+        "  <method name=\"Get\">\n"                                     \
+        "   <arg name=\"interface\" direction=\"in\" type=\"s\"/>\n"    \
+        "   <arg name=\"property\" direction=\"in\" type=\"s\"/>\n"     \
+        "   <arg name=\"value\" direction=\"out\" type=\"v\"/>\n"       \
+        "  </method>\n"                                                 \
+        "  <method name=\"GetAll\">\n"                                  \
+        "   <arg name=\"interface\" direction=\"in\" type=\"s\"/>\n"    \
+        "   <arg name=\"properties\" direction=\"out\" type=\"a{sv}\"/>\n" \
+        "  </method>\n"                                                 \
+        "  <method name=\"Set\">\n"                                     \
+        "   <arg name=\"interface\" direction=\"in\" type=\"s\"/>\n"    \
+        "   <arg name=\"property\" direction=\"in\" type=\"s\"/>\n"     \
+        "   <arg name=\"value\" direction=\"in\" type=\"v\"/>\n"        \
+        "  </method>\n"                                                 \
+        "  <signal name=\"PropertiesChanged\">\n"                       \
+        "   <arg type=\"s\" name=\"interface\"/>\n"                     \
+        "   <arg type=\"a{sv}\" name=\"changed_properties\"/>\n"        \
+        "   <arg type=\"as\" name=\"invalidated_properties\"/>\n"       \
+        "  </signal>\n"                                                 \
+        " </interface>\n"
+
+#define BUS_INTROSPECT_INTERFACE_OBJECT_MANAGER                      \
+        " <interface name=\"org.freedesktop.DBus.ObjectManager\">\n"    \
+        "  <method name=\"GetManagedObjects\">\n"                       \
+        "   <arg type=\"a{oa{sa{sv}}}\" name=\"object_paths_interfaces_and_properties\" direction=\"out\"/>\n" \
+        "  </method>\n"                                                 \
+        "  <signal name=\"InterfacesAdded\">\n"                         \
+        "   <arg type=\"o\" name=\"object_path\"/>\n"                   \
+        "   <arg type=\"a{sa{sv}}\" name=\"interfaces_and_properties\"/>\n" \
+        "  </signal>\n"                                                 \
+        "  <signal name=\"InterfacesRemoved\">\n"                       \
+        "   <arg type=\"o\" name=\"object_path\"/>\n"                   \
+        "   <arg type=\"as\" name=\"interfaces\"/>\n"                   \
+        "  </signal>\n"                                                 \
+        " </interface>\n"
+
+int introspect_begin(struct introspect *i, bool trusted) {
+        assert(i);
+
+        *i = (struct introspect) {
+                .trusted = trusted,
+        };
+
+        i->f = open_memstream_unlocked(&i->introspection, &i->size);
+        if (!i->f)
+                return -ENOMEM;
+
+        fputs(BUS_INTROSPECT_DOCTYPE
+              "<node>\n", i->f);
+
+        return 0;
+}
+
+int introspect_write_default_interfaces(struct introspect *i, bool object_manager) {
+        assert(i);
+
+        fputs(BUS_INTROSPECT_INTERFACE_PEER
+              BUS_INTROSPECT_INTERFACE_INTROSPECTABLE
+              BUS_INTROSPECT_INTERFACE_PROPERTIES, i->f);
+
+        if (object_manager)
+                fputs(BUS_INTROSPECT_INTERFACE_OBJECT_MANAGER, i->f);
+
+        return 0;
+}
+
+static int set_interface_name(struct introspect *intro, const char *interface_name) {
+        if (streq_ptr(intro->interface_name, interface_name))
+                return 0;
+
+        if (intro->interface_name)
+                fputs(" </interface>\n", intro->f);
+
+        if (interface_name)
+                fprintf(intro->f, " <interface name=\"%s\">\n", interface_name);
+
+        return free_and_strdup(&intro->interface_name, interface_name);
+}
+
+int introspect_write_child_nodes(struct introspect *i, Set *s, const char *prefix) {
+        char *node;
+
+        assert(i);
+        assert(prefix);
+
+        assert_se(set_interface_name(i, NULL) >= 0);
+
+        while ((node = set_steal_first(s))) {
+                const char *e;
+
+                e = object_path_startswith(node, prefix);
+                if (e && e[0])
+                        fprintf(i->f, " <node name=\"%s\"/>\n", e);
+
+                free(node);
+        }
+
+        return 0;
+}
+
+static void introspect_write_flags(struct introspect *i, int type, uint64_t flags) {
+        if (flags & SD_BUS_VTABLE_DEPRECATED)
+                fputs("   <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
+
+        if (type == _SD_BUS_VTABLE_METHOD && (flags & SD_BUS_VTABLE_METHOD_NO_REPLY))
+                fputs("   <annotation name=\"org.freedesktop.DBus.Method.NoReply\" value=\"true\"/>\n", i->f);
+
+        if (IN_SET(type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY)) {
+                if (flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
+                        fputs("   <annotation name=\"org.freedesktop.systemd1.Explicit\" value=\"true\"/>\n", i->f);
+
+                if (flags & SD_BUS_VTABLE_PROPERTY_CONST)
+                        fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"const\"/>\n", i->f);
+                else if (flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)
+                        fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"invalidates\"/>\n", i->f);
+                else if (!(flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
+                        fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>\n", i->f);
+        }
+
+        if (!i->trusted &&
+            IN_SET(type, _SD_BUS_VTABLE_METHOD, _SD_BUS_VTABLE_WRITABLE_PROPERTY) &&
+            !(flags & SD_BUS_VTABLE_UNPRIVILEGED))
+                fputs("   <annotation name=\"org.freedesktop.systemd1.Privileged\" value=\"true\"/>\n", i->f);
+}
+
+/* Note that "names" is both an input and an output parameter. It initially points to the first argument name in a
+   NULL-separated list of strings, and is then advanced with each argument, and the resulting pointer is returned. */
+static int introspect_write_arguments(struct introspect *i, const char *signature, const char **names, const char *direction) {
+        int r;
+
+        for (;;) {
+                size_t l;
+
+                if (!*signature)
+                        return 0;
+
+                r = signature_element_length(signature, &l);
+                if (r < 0)
+                        return r;
+
+                fprintf(i->f, "   <arg type=\"%.*s\"", (int) l, signature);
+
+                if (**names != '\0') {
+                        fprintf(i->f, " name=\"%s\"", *names);
+                        *names += strlen(*names) + 1;
+                }
+
+                if (direction)
+                        fprintf(i->f, " direction=\"%s\"/>\n", direction);
+                else
+                        fputs("/>\n", i->f);
+
+                signature += l;
+        }
+}
+
+int introspect_write_interface(
+                struct introspect *i,
+                const char *interface_name,
+                const sd_bus_vtable *v) {
+
+        const sd_bus_vtable *vtable = v;
+        const char *names = "";
+        int r;
+
+        assert(i);
+        assert(interface_name);
+        assert(v);
+
+        r = set_interface_name(i, interface_name);
+        if (r < 0)
+                return r;
+
+        for (; v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(vtable, v)) {
+
+                /* Ignore methods, signals and properties that are
+                 * marked "hidden", but do show the interface
+                 * itself */
+
+                if (v->type != _SD_BUS_VTABLE_START && (v->flags & SD_BUS_VTABLE_HIDDEN))
+                        continue;
+
+                switch (v->type) {
+
+                case _SD_BUS_VTABLE_START:
+                        if (v->flags & SD_BUS_VTABLE_DEPRECATED)
+                                fputs("  <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
+                        break;
+
+                case _SD_BUS_VTABLE_METHOD:
+                        fprintf(i->f, "  <method name=\"%s\">\n", v->x.method.member);
+                        if (bus_vtable_has_names(vtable))
+                                names = strempty(v->x.method.names);
+                        introspect_write_arguments(i, strempty(v->x.method.signature), &names, "in");
+                        introspect_write_arguments(i, strempty(v->x.method.result), &names, "out");
+                        introspect_write_flags(i, v->type, v->flags);
+                        fputs("  </method>\n", i->f);
+                        break;
+
+                case _SD_BUS_VTABLE_PROPERTY:
+                case _SD_BUS_VTABLE_WRITABLE_PROPERTY:
+                        fprintf(i->f, "  <property name=\"%s\" type=\"%s\" access=\"%s\">\n",
+                                v->x.property.member,
+                                v->x.property.signature,
+                                v->type == _SD_BUS_VTABLE_WRITABLE_PROPERTY ? "readwrite" : "read");
+                        introspect_write_flags(i, v->type, v->flags);
+                        fputs("  </property>\n", i->f);
+                        break;
+
+                case _SD_BUS_VTABLE_SIGNAL:
+                        fprintf(i->f, "  <signal name=\"%s\">\n", v->x.signal.member);
+                        if (bus_vtable_has_names(vtable))
+                                names = strempty(v->x.signal.names);
+                        introspect_write_arguments(i, strempty(v->x.signal.signature), &names, NULL);
+                        introspect_write_flags(i, v->type, v->flags);
+                        fputs("  </signal>\n", i->f);
+                        break;
+                }
+
+        }
+
+        return 0;
+}
+
+int introspect_finish(struct introspect *i, char **ret) {
+        int r;
+
+        assert(i);
+
+        assert_se(set_interface_name(i, NULL) >= 0);
+
+        fputs("</node>\n", i->f);
+
+        r = fflush_and_check(i->f);
+        if (r < 0)
+                return r;
+
+        i->f = safe_fclose(i->f);
+        *ret = TAKE_PTR(i->introspection);
+
+        return 0;
+}
+
+void introspect_free(struct introspect *i) {
+        assert(i);
+
+        /* Normally introspect_finish() does all the work, this is just a backup for error paths */
+
+        safe_fclose(i->f);
+        free(i->interface_name);
+        free(i->introspection);
+}
diff --git a/src/libsystemd/sd-bus/bus-introspect.h b/src/libsystemd/sd-bus/bus-introspect.h
new file mode 100644
index 0000000..34f32a4
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-introspect.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdio.h>
+
+#include "sd-bus.h"
+
+#include "set.h"
+
+struct introspect {
+        FILE *f;
+        char *interface_name;
+        char *introspection;
+        size_t size;
+        bool trusted;
+};
+
+int introspect_begin(struct introspect *i, bool trusted);
+int introspect_write_default_interfaces(struct introspect *i, bool object_manager);
+int introspect_write_child_nodes(struct introspect *i, Set *s, const char *prefix);
+int introspect_write_interface(
+                struct introspect *i,
+                const char *interface_name,
+                const sd_bus_vtable *v);
+int introspect_finish(struct introspect *i, char **ret);
+void introspect_free(struct introspect *i);
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
new file mode 100644
index 0000000..6bba446
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#if HAVE_VALGRIND_MEMCHECK_H
+#include <valgrind/memcheck.h>
+#endif
+
+#include <fcntl.h>
+#include <malloc.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+
+/* When we include libgen.h because we need dirname() we immediately
+ * undefine basename() since libgen.h defines it as a macro to the POSIX
+ * version which is really broken. We prefer GNU basename(). */
+#include <libgen.h>
+#undef basename
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-kernel.h"
+#include "bus-label.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "capability-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "memfd-util.h"
+#include "parse-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+#include "memory-util.h"
+
+void close_and_munmap(int fd, void *address, size_t size) {
+        if (size > 0)
+                assert_se(munmap(address, PAGE_ALIGN(size)) >= 0);
+
+        safe_close(fd);
+}
+
+void bus_flush_memfd(sd_bus *b) {
+        unsigned i;
+
+        assert(b);
+
+        for (i = 0; i < b->n_memfd_cache; i++)
+                close_and_munmap(b->memfd_cache[i].fd, b->memfd_cache[i].address, b->memfd_cache[i].mapped);
+}
diff --git a/src/libsystemd/sd-bus/bus-kernel.h b/src/libsystemd/sd-bus/bus-kernel.h
new file mode 100644
index 0000000..be8e0ce
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-kernel.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+#define MEMFD_CACHE_MAX 32
+
+/* When we cache a memfd block for reuse, we will truncate blocks
+ * longer than this in order not to keep too much data around. */
+#define MEMFD_CACHE_ITEM_SIZE_MAX (128*1024)
+
+/* This determines at which minimum size we prefer sending memfds over
+ * sending vectors */
+#define MEMFD_MIN_SIZE (512*1024)
+
+struct memfd_cache {
+        int fd;
+        void *address;
+        size_t mapped;
+        size_t allocated;
+};
+
+void close_and_munmap(int fd, void *address, size_t size);
+void bus_flush_memfd(sd_bus *bus);
diff --git a/src/libsystemd/sd-bus/bus-match.c b/src/libsystemd/sd-bus/bus-match.c
new file mode 100644
index 0000000..d7da4bf
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-match.c
@@ -0,0 +1,1100 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-match.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "hexdecoct.h"
+#include "sort-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+/* Example:
+ *
+ *  A: type=signal,sender=foo,interface=bar
+ *  B: type=signal,sender=quux,interface=fips
+ *  C: type=signal,sender=quux,interface=waldo
+ *  D: type=signal,member=test
+ *  E: sender=miau
+ *  F: type=signal
+ *  G: type=signal
+ *
+ *  results in this tree:
+ *
+ *  BUS_MATCH_ROOT
+ *  + BUS_MATCH_MESSAGE_TYPE
+ *  | ` BUS_MATCH_VALUE: value == signal
+ *  |   + DBUS_MATCH_SENDER
+ *  |   | + BUS_MATCH_VALUE: value == foo
+ *  |   | | ` DBUS_MATCH_INTERFACE
+ *  |   | |   ` BUS_MATCH_VALUE: value == bar
+ *  |   | |     ` BUS_MATCH_LEAF: A
+ *  |   | ` BUS_MATCH_VALUE: value == quux
+ *  |   |   ` DBUS_MATCH_INTERFACE
+ *  |   |     | BUS_MATCH_VALUE: value == fips
+ *  |   |     | ` BUS_MATCH_LEAF: B
+ *  |   |     ` BUS_MATCH_VALUE: value == waldo
+ *  |   |       ` BUS_MATCH_LEAF: C
+ *  |   + DBUS_MATCH_MEMBER
+ *  |   | ` BUS_MATCH_VALUE: value == test
+ *  |   |   ` BUS_MATCH_LEAF: D
+ *  |   + BUS_MATCH_LEAF: F
+ *  |   ` BUS_MATCH_LEAF: G
+ *  ` BUS_MATCH_SENDER
+ *    ` BUS_MATCH_VALUE: value == miau
+ *      ` BUS_MATCH_LEAF: E
+ */
+
+static bool BUS_MATCH_IS_COMPARE(enum bus_match_node_type t) {
+        return t >= BUS_MATCH_SENDER && t <= BUS_MATCH_ARG_HAS_LAST;
+}
+
+static bool BUS_MATCH_CAN_HASH(enum bus_match_node_type t) {
+        return (t >= BUS_MATCH_MESSAGE_TYPE && t <= BUS_MATCH_PATH) ||
+                (t >= BUS_MATCH_ARG && t <= BUS_MATCH_ARG_LAST) ||
+                (t >= BUS_MATCH_ARG_HAS && t <= BUS_MATCH_ARG_HAS_LAST);
+}
+
+static void bus_match_node_free(struct bus_match_node *node) {
+        assert(node);
+        assert(node->parent);
+        assert(!node->child);
+        assert(node->type != BUS_MATCH_ROOT);
+        assert(node->type < _BUS_MATCH_NODE_TYPE_MAX);
+
+        if (node->parent->child) {
+                /* We are apparently linked into the parent's child
+                 * list. Let's remove us from there. */
+                if (node->prev) {
+                        assert(node->prev->next == node);
+                        node->prev->next = node->next;
+                } else {
+                        assert(node->parent->child == node);
+                        node->parent->child = node->next;
+                }
+
+                if (node->next)
+                        node->next->prev = node->prev;
+        }
+
+        if (node->type == BUS_MATCH_VALUE) {
+                /* We might be in the parent's hash table, so clean
+                 * this up */
+
+                if (node->parent->type == BUS_MATCH_MESSAGE_TYPE)
+                        hashmap_remove(node->parent->compare.children, UINT_TO_PTR(node->value.u8));
+                else if (BUS_MATCH_CAN_HASH(node->parent->type) && node->value.str)
+                        hashmap_remove(node->parent->compare.children, node->value.str);
+
+                free(node->value.str);
+        }
+
+        if (BUS_MATCH_IS_COMPARE(node->type)) {
+                assert(hashmap_isempty(node->compare.children));
+                hashmap_free(node->compare.children);
+        }
+
+        free(node);
+}
+
+static bool bus_match_node_maybe_free(struct bus_match_node *node) {
+        assert(node);
+
+        if (node->type == BUS_MATCH_ROOT)
+                return false;
+
+        if (node->child)
+                return false;
+
+        if (BUS_MATCH_IS_COMPARE(node->type) && !hashmap_isempty(node->compare.children))
+                return true;
+
+        bus_match_node_free(node);
+        return true;
+}
+
+static bool value_node_test(
+                struct bus_match_node *node,
+                enum bus_match_node_type parent_type,
+                uint8_t value_u8,
+                const char *value_str,
+                char **value_strv,
+                sd_bus_message *m) {
+
+        assert(node);
+        assert(node->type == BUS_MATCH_VALUE);
+
+        /* Tests parameters against this value node, doing prefix
+         * magic and stuff. */
+
+        switch (parent_type) {
+
+        case BUS_MATCH_MESSAGE_TYPE:
+                return node->value.u8 == value_u8;
+
+        case BUS_MATCH_SENDER:
+                if (streq_ptr(node->value.str, value_str))
+                        return true;
+
+                if (m->creds.mask & SD_BUS_CREDS_WELL_KNOWN_NAMES) {
+                        char **i;
+
+                        /* on kdbus we have the well known names list
+                         * in the credentials, let's make use of that
+                         * for an accurate match */
+
+                        STRV_FOREACH(i, m->creds.well_known_names)
+                                if (streq_ptr(node->value.str, *i))
+                                        return true;
+
+                } else {
+
+                        /* If we don't have kdbus, we don't know the
+                         * well-known names of the senders. In that,
+                         * let's just hope that dbus-daemon doesn't
+                         * send us stuff we didn't want. */
+
+                        if (node->value.str[0] != ':' && value_str && value_str[0] == ':')
+                                return true;
+                }
+
+                return false;
+
+        case BUS_MATCH_DESTINATION:
+        case BUS_MATCH_INTERFACE:
+        case BUS_MATCH_MEMBER:
+        case BUS_MATCH_PATH:
+        case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+
+                if (value_str)
+                        return streq_ptr(node->value.str, value_str);
+
+                return false;
+
+        case BUS_MATCH_ARG_HAS ... BUS_MATCH_ARG_HAS_LAST: {
+                char **i;
+
+                STRV_FOREACH(i, value_strv)
+                        if (streq_ptr(node->value.str, *i))
+                                return true;
+
+                return false;
+        }
+
+        case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+                if (value_str)
+                        return namespace_simple_pattern(node->value.str, value_str);
+
+                return false;
+
+        case BUS_MATCH_PATH_NAMESPACE:
+                return path_simple_pattern(node->value.str, value_str);
+
+        case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+                if (value_str)
+                        return path_complex_pattern(node->value.str, value_str);
+
+                return false;
+
+        default:
+                assert_not_reached("Invalid node type");
+        }
+}
+
+static bool value_node_same(
+                struct bus_match_node *node,
+                enum bus_match_node_type parent_type,
+                uint8_t value_u8,
+                const char *value_str) {
+
+        /* Tests parameters against this value node, not doing prefix
+         * magic and stuff, i.e. this one actually compares the match
+         * itself. */
+
+        assert(node);
+        assert(node->type == BUS_MATCH_VALUE);
+
+        switch (parent_type) {
+
+        case BUS_MATCH_MESSAGE_TYPE:
+                return node->value.u8 == value_u8;
+
+        case BUS_MATCH_SENDER:
+        case BUS_MATCH_DESTINATION:
+        case BUS_MATCH_INTERFACE:
+        case BUS_MATCH_MEMBER:
+        case BUS_MATCH_PATH:
+        case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+        case BUS_MATCH_ARG_HAS ... BUS_MATCH_ARG_HAS_LAST:
+        case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+        case BUS_MATCH_PATH_NAMESPACE:
+        case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+                return streq(node->value.str, value_str);
+
+        default:
+                assert_not_reached("Invalid node type");
+        }
+}
+
+int bus_match_run(
+                sd_bus *bus,
+                struct bus_match_node *node,
+                sd_bus_message *m) {
+
+        _cleanup_strv_free_ char **test_strv = NULL;
+        const char *test_str = NULL;
+        uint8_t test_u8 = 0;
+        int r;
+
+        assert(m);
+
+        if (!node)
+                return 0;
+
+        if (bus && bus->match_callbacks_modified)
+                return 0;
+
+        /* Not these special semantics: when traversing the tree we
+         * usually let bus_match_run() when called for a node
+         * recursively invoke bus_match_run(). There's are two
+         * exceptions here though, which are BUS_NODE_ROOT (which
+         * cannot have a sibling), and BUS_NODE_VALUE (whose siblings
+         * are invoked anyway by its parent. */
+
+        switch (node->type) {
+
+        case BUS_MATCH_ROOT:
+
+                /* Run all children. Since we cannot have any siblings
+                 * we won't call any. The children of the root node
+                 * are compares or leaves, they will automatically
+                 * call their siblings. */
+                return bus_match_run(bus, node->child, m);
+
+        case BUS_MATCH_VALUE:
+
+                /* Run all children. We don't execute any siblings, we
+                 * assume our caller does that. The children of value
+                 * nodes are compares or leaves, they will
+                 * automatically call their siblings */
+
+                assert(node->child);
+                return bus_match_run(bus, node->child, m);
+
+        case BUS_MATCH_LEAF:
+
+                if (bus) {
+                        /* Don't run this match as long as the AddMatch() call is not complete yet.
+                         *
+                         * Don't run this match unless the 'after' counter has been reached.
+                         *
+                         * Don't run this match more than once per iteration */
+
+                        if (node->leaf.callback->install_slot ||
+                            m->read_counter <= node->leaf.callback->after ||
+                            node->leaf.callback->last_iteration == bus->iteration_counter)
+                                return bus_match_run(bus, node->next, m);
+
+                        node->leaf.callback->last_iteration = bus->iteration_counter;
+                }
+
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+
+                /* Run the callback. And then invoke siblings. */
+                if (node->leaf.callback->callback) {
+                        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+                        sd_bus_slot *slot;
+
+                        slot = container_of(node->leaf.callback, sd_bus_slot, match_callback);
+                        if (bus) {
+                                bus->current_slot = sd_bus_slot_ref(slot);
+                                bus->current_handler = node->leaf.callback->callback;
+                                bus->current_userdata = slot->userdata;
+                        }
+                        r = node->leaf.callback->callback(m, slot->userdata, &error_buffer);
+                        if (bus) {
+                                bus->current_userdata = NULL;
+                                bus->current_handler = NULL;
+                                bus->current_slot = sd_bus_slot_unref(slot);
+                        }
+
+                        r = bus_maybe_reply_error(m, r, &error_buffer);
+                        if (r != 0)
+                                return r;
+
+                        if (bus && bus->match_callbacks_modified)
+                                return 0;
+                }
+
+                return bus_match_run(bus, node->next, m);
+
+        case BUS_MATCH_MESSAGE_TYPE:
+                test_u8 = m->header->type;
+                break;
+
+        case BUS_MATCH_SENDER:
+                test_str = m->sender;
+                /* FIXME: resolve test_str from a well-known to a unique name first */
+                break;
+
+        case BUS_MATCH_DESTINATION:
+                test_str = m->destination;
+                break;
+
+        case BUS_MATCH_INTERFACE:
+                test_str = m->interface;
+                break;
+
+        case BUS_MATCH_MEMBER:
+                test_str = m->member;
+                break;
+
+        case BUS_MATCH_PATH:
+        case BUS_MATCH_PATH_NAMESPACE:
+                test_str = m->path;
+                break;
+
+        case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+                (void) bus_message_get_arg(m, node->type - BUS_MATCH_ARG, &test_str);
+                break;
+
+        case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+                (void) bus_message_get_arg(m, node->type - BUS_MATCH_ARG_PATH, &test_str);
+                break;
+
+        case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+                (void) bus_message_get_arg(m, node->type - BUS_MATCH_ARG_NAMESPACE, &test_str);
+                break;
+
+        case BUS_MATCH_ARG_HAS ... BUS_MATCH_ARG_HAS_LAST:
+                (void) bus_message_get_arg_strv(m, node->type - BUS_MATCH_ARG_HAS, &test_strv);
+                break;
+
+        default:
+                assert_not_reached("Unknown match type.");
+        }
+
+        if (BUS_MATCH_CAN_HASH(node->type)) {
+                struct bus_match_node *found;
+
+                /* Lookup via hash table, nice! So let's jump directly. */
+
+                if (test_str)
+                        found = hashmap_get(node->compare.children, test_str);
+                else if (test_strv) {
+                        char **i;
+
+                        STRV_FOREACH(i, test_strv) {
+                                found = hashmap_get(node->compare.children, *i);
+                                if (found) {
+                                        r = bus_match_run(bus, found, m);
+                                        if (r != 0)
+                                                return r;
+                                }
+                        }
+
+                        found = NULL;
+                } else if (node->type == BUS_MATCH_MESSAGE_TYPE)
+                        found = hashmap_get(node->compare.children, UINT_TO_PTR(test_u8));
+                else
+                        found = NULL;
+
+                if (found) {
+                        r = bus_match_run(bus, found, m);
+                        if (r != 0)
+                                return r;
+                }
+        } else {
+                struct bus_match_node *c;
+
+                /* No hash table, so let's iterate manually... */
+
+                for (c = node->child; c; c = c->next) {
+                        if (!value_node_test(c, node->type, test_u8, test_str, test_strv, m))
+                                continue;
+
+                        r = bus_match_run(bus, c, m);
+                        if (r != 0)
+                                return r;
+
+                        if (bus && bus->match_callbacks_modified)
+                                return 0;
+                }
+        }
+
+        if (bus && bus->match_callbacks_modified)
+                return 0;
+
+        /* And now, let's invoke our siblings */
+        return bus_match_run(bus, node->next, m);
+}
+
+static int bus_match_add_compare_value(
+                struct bus_match_node *where,
+                enum bus_match_node_type t,
+                uint8_t value_u8,
+                const char *value_str,
+                struct bus_match_node **ret) {
+
+        struct bus_match_node *c = NULL, *n = NULL;
+        int r;
+
+        assert(where);
+        assert(IN_SET(where->type, BUS_MATCH_ROOT, BUS_MATCH_VALUE));
+        assert(BUS_MATCH_IS_COMPARE(t));
+        assert(ret);
+
+        for (c = where->child; c && c->type != t; c = c->next)
+                ;
+
+        if (c) {
+                /* Comparison node already exists? Then let's see if
+                 * the value node exists too. */
+
+                if (t == BUS_MATCH_MESSAGE_TYPE)
+                        n = hashmap_get(c->compare.children, UINT_TO_PTR(value_u8));
+                else if (BUS_MATCH_CAN_HASH(t))
+                        n = hashmap_get(c->compare.children, value_str);
+                else {
+                        for (n = c->child; n && !value_node_same(n, t, value_u8, value_str); n = n->next)
+                                ;
+                }
+
+                if (n) {
+                        *ret = n;
+                        return 0;
+                }
+        } else {
+                /* Comparison node, doesn't exist yet? Then let's
+                 * create it. */
+
+                c = new0(struct bus_match_node, 1);
+                if (!c) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                c->type = t;
+                c->parent = where;
+                c->next = where->child;
+                if (c->next)
+                        c->next->prev = c;
+                where->child = c;
+
+                if (t == BUS_MATCH_MESSAGE_TYPE) {
+                        c->compare.children = hashmap_new(NULL);
+                        if (!c->compare.children) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+                } else if (BUS_MATCH_CAN_HASH(t)) {
+                        c->compare.children = hashmap_new(&string_hash_ops);
+                        if (!c->compare.children) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+                }
+        }
+
+        n = new0(struct bus_match_node, 1);
+        if (!n) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        n->type = BUS_MATCH_VALUE;
+        n->value.u8 = value_u8;
+        if (value_str) {
+                n->value.str = strdup(value_str);
+                if (!n->value.str) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        n->parent = c;
+        if (c->compare.children) {
+
+                if (t == BUS_MATCH_MESSAGE_TYPE)
+                        r = hashmap_put(c->compare.children, UINT_TO_PTR(value_u8), n);
+                else
+                        r = hashmap_put(c->compare.children, n->value.str, n);
+
+                if (r < 0)
+                        goto fail;
+        } else {
+                n->next = c->child;
+                if (n->next)
+                        n->next->prev = n;
+                c->child = n;
+        }
+
+        *ret = n;
+        return 1;
+
+fail:
+        if (c)
+                bus_match_node_maybe_free(c);
+
+        if (n) {
+                free(n->value.str);
+                free(n);
+        }
+
+        return r;
+}
+
+static int bus_match_add_leaf(
+                struct bus_match_node *where,
+                struct match_callback *callback) {
+
+        struct bus_match_node *n;
+
+        assert(where);
+        assert(IN_SET(where->type, BUS_MATCH_ROOT, BUS_MATCH_VALUE));
+        assert(callback);
+
+        n = new0(struct bus_match_node, 1);
+        if (!n)
+                return -ENOMEM;
+
+        n->type = BUS_MATCH_LEAF;
+        n->parent = where;
+        n->next = where->child;
+        if (n->next)
+                n->next->prev = n;
+
+        n->leaf.callback = callback;
+        callback->match_node = n;
+
+        where->child = n;
+
+        return 1;
+}
+
+enum bus_match_node_type bus_match_node_type_from_string(const char *k, size_t n) {
+        assert(k);
+
+        if (n == 4 && startswith(k, "type"))
+                return BUS_MATCH_MESSAGE_TYPE;
+        if (n == 6 && startswith(k, "sender"))
+                return BUS_MATCH_SENDER;
+        if (n == 11 && startswith(k, "destination"))
+                return BUS_MATCH_DESTINATION;
+        if (n == 9 && startswith(k, "interface"))
+                return BUS_MATCH_INTERFACE;
+        if (n == 6 && startswith(k, "member"))
+                return BUS_MATCH_MEMBER;
+        if (n == 4 && startswith(k, "path"))
+                return BUS_MATCH_PATH;
+        if (n == 14 && startswith(k, "path_namespace"))
+                return BUS_MATCH_PATH_NAMESPACE;
+
+        if (n == 4 && startswith(k, "arg")) {
+                int j;
+
+                j = undecchar(k[3]);
+                if (j < 0)
+                        return -EINVAL;
+
+                return BUS_MATCH_ARG + j;
+        }
+
+        if (n == 5 && startswith(k, "arg")) {
+                int a, b;
+                enum bus_match_node_type t;
+
+                a = undecchar(k[3]);
+                b = undecchar(k[4]);
+                if (a <= 0 || b < 0)
+                        return -EINVAL;
+
+                t = BUS_MATCH_ARG + a * 10 + b;
+                if (t > BUS_MATCH_ARG_LAST)
+                        return -EINVAL;
+
+                return t;
+        }
+
+        if (n == 8 && startswith(k, "arg") && startswith(k + 4, "path")) {
+                int j;
+
+                j = undecchar(k[3]);
+                if (j < 0)
+                        return -EINVAL;
+
+                return BUS_MATCH_ARG_PATH + j;
+        }
+
+        if (n == 9 && startswith(k, "arg") && startswith(k + 5, "path")) {
+                enum bus_match_node_type t;
+                int a, b;
+
+                a = undecchar(k[3]);
+                b = undecchar(k[4]);
+                if (a <= 0 || b < 0)
+                        return -EINVAL;
+
+                t = BUS_MATCH_ARG_PATH + a * 10 + b;
+                if (t > BUS_MATCH_ARG_PATH_LAST)
+                        return -EINVAL;
+
+                return t;
+        }
+
+        if (n == 13 && startswith(k, "arg") && startswith(k + 4, "namespace")) {
+                int j;
+
+                j = undecchar(k[3]);
+                if (j < 0)
+                        return -EINVAL;
+
+                return BUS_MATCH_ARG_NAMESPACE + j;
+        }
+
+        if (n == 14 && startswith(k, "arg") && startswith(k + 5, "namespace")) {
+                enum bus_match_node_type t;
+                int a, b;
+
+                a = undecchar(k[3]);
+                b = undecchar(k[4]);
+                if (a <= 0 || b < 0)
+                        return -EINVAL;
+
+                t = BUS_MATCH_ARG_NAMESPACE + a * 10 + b;
+                if (t > BUS_MATCH_ARG_NAMESPACE_LAST)
+                        return -EINVAL;
+
+                return t;
+        }
+
+        if (n == 7 && startswith(k, "arg") && startswith(k + 4, "has")) {
+                int j;
+
+                j = undecchar(k[3]);
+                if (j < 0)
+                        return -EINVAL;
+
+                return BUS_MATCH_ARG_HAS + j;
+        }
+
+        if (n == 8 && startswith(k, "arg") && startswith(k + 5, "has")) {
+                enum bus_match_node_type t;
+                int a, b;
+
+                a = undecchar(k[3]);
+                b = undecchar(k[4]);
+                if (a <= 0 || b < 0)
+                        return -EINVAL;
+
+                t = BUS_MATCH_ARG_HAS + a * 10 + b;
+                if (t > BUS_MATCH_ARG_HAS_LAST)
+                        return -EINVAL;
+
+                return t;
+        }
+
+        return -EINVAL;
+}
+
+static int match_component_compare(const struct bus_match_component *a, const struct bus_match_component *b) {
+        return CMP(a->type, b->type);
+}
+
+void bus_match_parse_free(struct bus_match_component *components, unsigned n_components) {
+        unsigned i;
+
+        for (i = 0; i < n_components; i++)
+                free(components[i].value_str);
+
+        free(components);
+}
+
+int bus_match_parse(
+                const char *match,
+                struct bus_match_component **_components,
+                unsigned *_n_components) {
+
+        const char *p = match;
+        struct bus_match_component *components = NULL;
+        size_t components_allocated = 0;
+        unsigned n_components = 0, i;
+        _cleanup_free_ char *value = NULL;
+        int r;
+
+        assert(match);
+        assert(_components);
+        assert(_n_components);
+
+        while (*p != 0) {
+                const char *eq, *q;
+                enum bus_match_node_type t;
+                unsigned j = 0;
+                size_t value_allocated = 0;
+                bool escaped = false, quoted;
+                uint8_t u;
+
+                /* Avahi's match rules appear to include whitespace, skip over it */
+                p += strspn(p, " ");
+
+                eq = strchr(p, '=');
+                if (!eq)
+                        return -EINVAL;
+
+                t = bus_match_node_type_from_string(p, eq - p);
+                if (t < 0)
+                        return -EINVAL;
+
+                quoted = eq[1] == '\'';
+
+                for (q = eq + 1 + quoted;; q++) {
+
+                        if (*q == 0) {
+
+                                if (quoted) {
+                                        r = -EINVAL;
+                                        goto fail;
+                                } else {
+                                        if (value)
+                                                value[j] = 0;
+                                        break;
+                                }
+                        }
+
+                        if (!escaped) {
+                                if (*q == '\\') {
+                                        escaped = true;
+                                        continue;
+                                }
+
+                                if (quoted) {
+                                        if (*q == '\'') {
+                                                if (value)
+                                                        value[j] = 0;
+                                                break;
+                                        }
+                                } else {
+                                        if (*q == ',') {
+                                                if (value)
+                                                        value[j] = 0;
+
+                                                break;
+                                        }
+                                }
+                        }
+
+                        if (!GREEDY_REALLOC(value, value_allocated, j + 2)) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        value[j++] = *q;
+                        escaped = false;
+                }
+
+                if (!value) {
+                        value = strdup("");
+                        if (!value) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+                }
+
+                if (t == BUS_MATCH_MESSAGE_TYPE) {
+                        r = bus_message_type_from_string(value, &u);
+                        if (r < 0)
+                                goto fail;
+
+                        value = mfree(value);
+                } else
+                        u = 0;
+
+                if (!GREEDY_REALLOC(components, components_allocated, n_components + 1)) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                components[n_components].type = t;
+                components[n_components].value_str = TAKE_PTR(value);
+                components[n_components].value_u8 = u;
+                n_components++;
+
+                if (q[quoted] == 0)
+                        break;
+
+                if (q[quoted] != ',') {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+                p = q + 1 + quoted;
+        }
+
+        /* Order the whole thing, so that we always generate the same tree */
+        typesafe_qsort(components, n_components, match_component_compare);
+
+        /* Check for duplicates */
+        for (i = 0; i+1 < n_components; i++)
+                if (components[i].type == components[i+1].type) {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+        *_components = components;
+        *_n_components = n_components;
+
+        return 0;
+
+fail:
+        bus_match_parse_free(components, n_components);
+        return r;
+}
+
+char *bus_match_to_string(struct bus_match_component *components, unsigned n_components) {
+        _cleanup_fclose_ FILE *f = NULL;
+        char *buffer = NULL;
+        size_t size = 0;
+        unsigned i;
+        int r;
+
+        if (n_components <= 0)
+                return strdup("");
+
+        assert(components);
+
+        f = open_memstream_unlocked(&buffer, &size);
+        if (!f)
+                return NULL;
+
+        for (i = 0; i < n_components; i++) {
+                char buf[32];
+
+                if (i != 0)
+                        fputc(',', f);
+
+                fputs(bus_match_node_type_to_string(components[i].type, buf, sizeof(buf)), f);
+                fputc('=', f);
+                fputc('\'', f);
+
+                if (components[i].type == BUS_MATCH_MESSAGE_TYPE)
+                        fputs(bus_message_type_to_string(components[i].value_u8), f);
+                else
+                        fputs(components[i].value_str, f);
+
+                fputc('\'', f);
+        }
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                return NULL;
+
+        return buffer;
+}
+
+int bus_match_add(
+                struct bus_match_node *root,
+                struct bus_match_component *components,
+                unsigned n_components,
+                struct match_callback *callback) {
+
+        unsigned i;
+        struct bus_match_node *n;
+        int r;
+
+        assert(root);
+        assert(callback);
+
+        n = root;
+        for (i = 0; i < n_components; i++) {
+                r = bus_match_add_compare_value(
+                                n, components[i].type,
+                                components[i].value_u8, components[i].value_str, &n);
+                if (r < 0)
+                        return r;
+        }
+
+        return bus_match_add_leaf(n, callback);
+}
+
+int bus_match_remove(
+                struct bus_match_node *root,
+                struct match_callback *callback) {
+
+        struct bus_match_node *node, *pp;
+
+        assert(root);
+        assert(callback);
+
+        node = callback->match_node;
+        if (!node)
+                return 0;
+
+        assert(node->type == BUS_MATCH_LEAF);
+
+        callback->match_node = NULL;
+
+        /* Free the leaf */
+        pp = node->parent;
+        bus_match_node_free(node);
+
+        /* Prune the tree above */
+        while (pp) {
+                node = pp;
+                pp = node->parent;
+
+                if (!bus_match_node_maybe_free(node))
+                        break;
+        }
+
+        return 1;
+}
+
+void bus_match_free(struct bus_match_node *node) {
+        struct bus_match_node *c;
+
+        if (!node)
+                return;
+
+        if (BUS_MATCH_CAN_HASH(node->type)) {
+
+                HASHMAP_FOREACH(c, node->compare.children)
+                        bus_match_free(c);
+
+                assert(hashmap_isempty(node->compare.children));
+        }
+
+        while ((c = node->child))
+                bus_match_free(c);
+
+        if (node->type != BUS_MATCH_ROOT)
+                bus_match_node_free(node);
+}
+
+const char* bus_match_node_type_to_string(enum bus_match_node_type t, char buf[], size_t l) {
+        switch (t) {
+
+        case BUS_MATCH_ROOT:
+                return "root";
+
+        case BUS_MATCH_VALUE:
+                return "value";
+
+        case BUS_MATCH_LEAF:
+                return "leaf";
+
+        case BUS_MATCH_MESSAGE_TYPE:
+                return "type";
+
+        case BUS_MATCH_SENDER:
+                return "sender";
+
+        case BUS_MATCH_DESTINATION:
+                return "destination";
+
+        case BUS_MATCH_INTERFACE:
+                return "interface";
+
+        case BUS_MATCH_MEMBER:
+                return "member";
+
+        case BUS_MATCH_PATH:
+                return "path";
+
+        case BUS_MATCH_PATH_NAMESPACE:
+                return "path_namespace";
+
+        case BUS_MATCH_ARG ... BUS_MATCH_ARG_LAST:
+                snprintf(buf, l, "arg%i", t - BUS_MATCH_ARG);
+                return buf;
+
+        case BUS_MATCH_ARG_PATH ... BUS_MATCH_ARG_PATH_LAST:
+                snprintf(buf, l, "arg%ipath", t - BUS_MATCH_ARG_PATH);
+                return buf;
+
+        case BUS_MATCH_ARG_NAMESPACE ... BUS_MATCH_ARG_NAMESPACE_LAST:
+                snprintf(buf, l, "arg%inamespace", t - BUS_MATCH_ARG_NAMESPACE);
+                return buf;
+
+        case BUS_MATCH_ARG_HAS ... BUS_MATCH_ARG_HAS_LAST:
+                snprintf(buf, l, "arg%ihas", t - BUS_MATCH_ARG_HAS);
+                return buf;
+
+        default:
+                return NULL;
+        }
+}
+
+void bus_match_dump(struct bus_match_node *node, unsigned level) {
+        struct bus_match_node *c;
+        _cleanup_free_ char *pfx = NULL;
+        char buf[32];
+
+        if (!node)
+                return;
+
+        pfx = strrep("  ", level);
+        printf("%s[%s]", strempty(pfx), bus_match_node_type_to_string(node->type, buf, sizeof(buf)));
+
+        if (node->type == BUS_MATCH_VALUE) {
+                if (node->parent->type == BUS_MATCH_MESSAGE_TYPE)
+                        printf(" <%u>\n", node->value.u8);
+                else
+                        printf(" <%s>\n", node->value.str);
+        } else if (node->type == BUS_MATCH_ROOT)
+                puts(" root");
+        else if (node->type == BUS_MATCH_LEAF)
+                printf(" %p/%p\n", node->leaf.callback->callback, container_of(node->leaf.callback, sd_bus_slot, match_callback)->userdata);
+        else
+                putchar('\n');
+
+        if (BUS_MATCH_CAN_HASH(node->type)) {
+
+                HASHMAP_FOREACH(c, node->compare.children)
+                        bus_match_dump(c, level + 1);
+        }
+
+        for (c = node->child; c; c = c->next)
+                bus_match_dump(c, level + 1);
+}
+
+enum bus_match_scope bus_match_get_scope(const struct bus_match_component *components, unsigned n_components) {
+        bool found_driver = false;
+        unsigned i;
+
+        if (n_components <= 0)
+                return BUS_MATCH_GENERIC;
+
+        assert(components);
+
+        /* Checks whether the specified match can only match the
+         * pseudo-service for local messages, which we detect by
+         * sender, interface or path. If a match is not restricted to
+         * local messages, then we check if it only matches on the
+         * driver. */
+
+        for (i = 0; i < n_components; i++) {
+                const struct bus_match_component *c = components + i;
+
+                if (c->type == BUS_MATCH_SENDER) {
+                        if (streq_ptr(c->value_str, "org.freedesktop.DBus.Local"))
+                                return BUS_MATCH_LOCAL;
+
+                        if (streq_ptr(c->value_str, "org.freedesktop.DBus"))
+                                found_driver = true;
+                }
+
+                if (c->type == BUS_MATCH_INTERFACE && streq_ptr(c->value_str, "org.freedesktop.DBus.Local"))
+                        return BUS_MATCH_LOCAL;
+
+                if (c->type == BUS_MATCH_PATH && streq_ptr(c->value_str, "/org/freedesktop/DBus/Local"))
+                        return BUS_MATCH_LOCAL;
+        }
+
+        return found_driver ? BUS_MATCH_DRIVER : BUS_MATCH_GENERIC;
+
+}
diff --git a/src/libsystemd/sd-bus/bus-match.h b/src/libsystemd/sd-bus/bus-match.h
new file mode 100644
index 0000000..e44e406
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-match.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+#include "hashmap.h"
+
+enum bus_match_node_type {
+        BUS_MATCH_ROOT,
+        BUS_MATCH_VALUE,
+        BUS_MATCH_LEAF,
+
+        /* The following are all different kinds of compare nodes */
+        BUS_MATCH_SENDER,
+        BUS_MATCH_MESSAGE_TYPE,
+        BUS_MATCH_DESTINATION,
+        BUS_MATCH_INTERFACE,
+        BUS_MATCH_MEMBER,
+        BUS_MATCH_PATH,
+        BUS_MATCH_PATH_NAMESPACE,
+        BUS_MATCH_ARG,
+        BUS_MATCH_ARG_LAST = BUS_MATCH_ARG + 63,
+        BUS_MATCH_ARG_PATH,
+        BUS_MATCH_ARG_PATH_LAST = BUS_MATCH_ARG_PATH + 63,
+        BUS_MATCH_ARG_NAMESPACE,
+        BUS_MATCH_ARG_NAMESPACE_LAST = BUS_MATCH_ARG_NAMESPACE + 63,
+        BUS_MATCH_ARG_HAS,
+        BUS_MATCH_ARG_HAS_LAST = BUS_MATCH_ARG_HAS + 63,
+        _BUS_MATCH_NODE_TYPE_MAX,
+        _BUS_MATCH_NODE_TYPE_INVALID = -1
+};
+
+struct bus_match_node {
+        enum bus_match_node_type type;
+        struct bus_match_node *parent, *next, *prev, *child;
+
+        union {
+                struct {
+                        char *str;
+                        uint8_t u8;
+                } value;
+                struct {
+                        struct match_callback *callback;
+                } leaf;
+                struct {
+                        /* If this is set, then the child is NULL */
+                        Hashmap *children;
+                } compare;
+        };
+};
+
+struct bus_match_component {
+        enum bus_match_node_type type;
+        uint8_t value_u8;
+        char *value_str;
+};
+
+enum bus_match_scope {
+        BUS_MATCH_GENERIC,
+        BUS_MATCH_LOCAL,
+        BUS_MATCH_DRIVER,
+};
+
+int bus_match_run(sd_bus *bus, struct bus_match_node *root, sd_bus_message *m);
+
+int bus_match_add(struct bus_match_node *root, struct bus_match_component *components, unsigned n_components, struct match_callback *callback);
+int bus_match_remove(struct bus_match_node *root, struct match_callback *callback);
+
+void bus_match_free(struct bus_match_node *node);
+
+void bus_match_dump(struct bus_match_node *node, unsigned level);
+
+const char* bus_match_node_type_to_string(enum bus_match_node_type t, char buf[], size_t l);
+enum bus_match_node_type bus_match_node_type_from_string(const char *k, size_t n);
+
+int bus_match_parse(const char *match, struct bus_match_component **_components, unsigned *_n_components);
+void bus_match_parse_free(struct bus_match_component *components, unsigned n_components);
+char *bus_match_to_string(struct bus_match_component *components, unsigned n_components);
+
+enum bus_match_scope bus_match_get_scope(const struct bus_match_component *components, unsigned n_components);
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
new file mode 100644
index 0000000..86ff5bd
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -0,0 +1,5973 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-gvariant.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-signature.h"
+#include "bus-type.h"
+#include "bus-util.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "memfd-util.h"
+#include "memory-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "utf8.h"
+
+static int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored);
+
+static void *adjust_pointer(const void *p, void *old_base, size_t sz, void *new_base) {
+
+        if (!p)
+                return NULL;
+
+        if (old_base == new_base)
+                return (void*) p;
+
+        if ((uint8_t*) p < (uint8_t*) old_base)
+                return (void*) p;
+
+        if ((uint8_t*) p >= (uint8_t*) old_base + sz)
+                return (void*) p;
+
+        return (uint8_t*) new_base + ((uint8_t*) p - (uint8_t*) old_base);
+}
+
+static void message_free_part(sd_bus_message *m, struct bus_body_part *part) {
+        assert(m);
+        assert(part);
+
+        if (part->memfd >= 0) {
+                /* erase if requested, but only if the memfd is not sealed yet, i.e. is writable */
+                if (m->sensitive && !m->sealed)
+                        explicit_bzero_safe(part->data, part->size);
+
+                close_and_munmap(part->memfd, part->mmap_begin, part->mapped);
+        } else if (part->munmap_this)
+                /* We don't erase sensitive data here, since the data is memory mapped from someone else, and
+                 * we just don't know if it's OK to write to it */
+                munmap(part->mmap_begin, part->mapped);
+        else {
+                /* Erase this if that is requested. Since this is regular memory we know we can write it. */
+                if (m->sensitive)
+                        explicit_bzero_safe(part->data, part->size);
+
+                if (part->free_this)
+                        free(part->data);
+        }
+
+        if (part != &m->body)
+                free(part);
+}
+
+static void message_reset_parts(sd_bus_message *m) {
+        struct bus_body_part *part;
+
+        assert(m);
+
+        part = &m->body;
+        while (m->n_body_parts > 0) {
+                struct bus_body_part *next = part->next;
+                message_free_part(m, part);
+                part = next;
+                m->n_body_parts--;
+        }
+
+        m->body_end = NULL;
+
+        m->cached_rindex_part = NULL;
+        m->cached_rindex_part_begin = 0;
+}
+
+static struct bus_container *message_get_last_container(sd_bus_message *m) {
+        assert(m);
+
+        if (m->n_containers == 0)
+                return &m->root_container;
+
+        assert(m->containers);
+        return m->containers + m->n_containers - 1;
+}
+
+static void message_free_last_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        c = message_get_last_container(m);
+
+        free(c->signature);
+        free(c->peeked_signature);
+        free(c->offsets);
+
+        /* Move to previous container, but not if we are on root container */
+        if (m->n_containers > 0)
+                m->n_containers--;
+}
+
+static void message_reset_containers(sd_bus_message *m) {
+        assert(m);
+
+        while (m->n_containers > 0)
+                message_free_last_container(m);
+
+        m->containers = mfree(m->containers);
+        m->containers_allocated = 0;
+        m->root_container.index = 0;
+}
+
+static sd_bus_message* message_free(sd_bus_message *m) {
+        assert(m);
+
+        message_reset_parts(m);
+
+        if (m->free_header)
+                free(m->header);
+
+        /* Note that we don't unref m->bus here. That's already done by sd_bus_message_unref() as each user
+         * reference to the bus message also is considered a reference to the bus connection itself. */
+
+        if (m->free_fds) {
+                close_many(m->fds, m->n_fds);
+                free(m->fds);
+        }
+
+        if (m->iovec != m->iovec_fixed)
+                free(m->iovec);
+
+        message_reset_containers(m);
+        assert(m->n_containers == 0);
+        message_free_last_container(m);
+
+        bus_creds_done(&m->creds);
+        return mfree(m);
+}
+
+static void *message_extend_fields(sd_bus_message *m, size_t align, size_t sz, bool add_offset) {
+        void *op, *np;
+        size_t old_size, new_size, start;
+
+        assert(m);
+
+        if (m->poisoned)
+                return NULL;
+
+        old_size = sizeof(struct bus_header) + m->fields_size;
+        start = ALIGN_TO(old_size, align);
+        new_size = start + sz;
+
+        if (new_size < start ||
+            new_size > (size_t) ((uint32_t) -1))
+                goto poison;
+
+        if (old_size == new_size)
+                return (uint8_t*) m->header + old_size;
+
+        if (m->free_header) {
+                np = realloc(m->header, ALIGN8(new_size));
+                if (!np)
+                        goto poison;
+        } else {
+                /* Initially, the header is allocated as part of
+                 * the sd_bus_message itself, let's replace it by
+                 * dynamic data */
+
+                np = malloc(ALIGN8(new_size));
+                if (!np)
+                        goto poison;
+
+                memcpy(np, m->header, sizeof(struct bus_header));
+        }
+
+        /* Zero out padding */
+        if (start > old_size)
+                memzero((uint8_t*) np + old_size, start - old_size);
+
+        op = m->header;
+        m->header = np;
+        m->fields_size = new_size - sizeof(struct bus_header);
+
+        /* Adjust quick access pointers */
+        m->path = adjust_pointer(m->path, op, old_size, m->header);
+        m->interface = adjust_pointer(m->interface, op, old_size, m->header);
+        m->member = adjust_pointer(m->member, op, old_size, m->header);
+        m->destination = adjust_pointer(m->destination, op, old_size, m->header);
+        m->sender = adjust_pointer(m->sender, op, old_size, m->header);
+        m->error.name = adjust_pointer(m->error.name, op, old_size, m->header);
+
+        m->free_header = true;
+
+        if (add_offset) {
+                if (m->n_header_offsets >= ELEMENTSOF(m->header_offsets))
+                        goto poison;
+
+                m->header_offsets[m->n_header_offsets++] = new_size - sizeof(struct bus_header);
+        }
+
+        return (uint8_t*) np + start;
+
+poison:
+        m->poisoned = true;
+        return NULL;
+}
+
+static int message_append_field_string(
+                sd_bus_message *m,
+                uint64_t h,
+                char type,
+                const char *s,
+                const char **ret) {
+
+        size_t l;
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus1 only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        /* dbus1 doesn't allow strings over 32bit, let's enforce this
+         * globally, to not risk convertability */
+        l = strlen(s);
+        if (l > UINT32_MAX)
+                return -EINVAL;
+
+        /* Signature "(yv)" where the variant contains "s" */
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+
+                /* (field id 64bit, ((string + NUL) + NUL + signature string 's') */
+                p = message_extend_fields(m, 8, 8 + l + 1 + 1 + 1, true);
+                if (!p)
+                        return -ENOMEM;
+
+                *((uint64_t*) p) = h;
+                memcpy(p+8, s, l);
+                p[8+l] = 0;
+                p[8+l+1] = 0;
+                p[8+l+2] = type;
+
+                if (ret)
+                        *ret = (char*) p + 8;
+
+        } else {
+                /* (field id byte + (signature length + signature 's' + NUL) + (string length + string + NUL)) */
+                p = message_extend_fields(m, 8, 4 + 4 + l + 1, false);
+                if (!p)
+                        return -ENOMEM;
+
+                p[0] = (uint8_t) h;
+                p[1] = 1;
+                p[2] = type;
+                p[3] = 0;
+
+                ((uint32_t*) p)[1] = l;
+                memcpy(p + 8, s, l + 1);
+
+                if (ret)
+                        *ret = (char*) p + 8;
+        }
+
+        return 0;
+}
+
+static int message_append_field_signature(
+                sd_bus_message *m,
+                uint64_t h,
+                const char *s,
+                const char **ret) {
+
+        size_t l;
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus1 only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        /* dbus1 doesn't allow signatures over 8bit, let's enforce
+         * this globally, to not risk convertability */
+        l = strlen(s);
+        if (l > SD_BUS_MAXIMUM_SIGNATURE_LENGTH)
+                return -EINVAL;
+
+        /* Signature "(yv)" where the variant contains "g" */
+
+        if (BUS_MESSAGE_IS_GVARIANT(m))
+                /* For gvariant the serialization is the same as for normal strings */
+                return message_append_field_string(m, h, 'g', s, ret);
+        else {
+                /* (field id byte + (signature length + signature 'g' + NUL) + (string length + string + NUL)) */
+                p = message_extend_fields(m, 8, 4 + 1 + l + 1, false);
+                if (!p)
+                        return -ENOMEM;
+
+                p[0] = (uint8_t) h;
+                p[1] = 1;
+                p[2] = SD_BUS_TYPE_SIGNATURE;
+                p[3] = 0;
+                p[4] = l;
+                memcpy(p + 5, s, l + 1);
+
+                if (ret)
+                        *ret = (const char*) p + 5;
+        }
+
+        return 0;
+}
+
+static int message_append_field_uint32(sd_bus_message *m, uint64_t h, uint32_t x) {
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus1 only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                /* (field id 64bit + ((value + NUL + signature string 'u') */
+
+                p = message_extend_fields(m, 8, 8 + 4 + 1 + 1, true);
+                if (!p)
+                        return -ENOMEM;
+
+                *((uint64_t*) p) = h;
+                *((uint32_t*) (p + 8)) = x;
+                p[12] = 0;
+                p[13] = 'u';
+        } else {
+                /* (field id byte + (signature length + signature 'u' + NUL) + value) */
+                p = message_extend_fields(m, 8, 4 + 4, false);
+                if (!p)
+                        return -ENOMEM;
+
+                p[0] = (uint8_t) h;
+                p[1] = 1;
+                p[2] = 'u';
+                p[3] = 0;
+
+                ((uint32_t*) p)[1] = x;
+        }
+
+        return 0;
+}
+
+static int message_append_field_uint64(sd_bus_message *m, uint64_t h, uint64_t x) {
+        uint8_t *p;
+
+        assert(m);
+
+        /* dbus1 only allows 8bit header field ids */
+        if (h > 0xFF)
+                return -EINVAL;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                /* (field id 64bit + ((value + NUL + signature string 't') */
+
+                p = message_extend_fields(m, 8, 8 + 8 + 1 + 1, true);
+                if (!p)
+                        return -ENOMEM;
+
+                *((uint64_t*) p) = h;
+                *((uint64_t*) (p + 8)) = x;
+                p[16] = 0;
+                p[17] = 't';
+        } else {
+                /* (field id byte + (signature length + signature 't' + NUL) + 4 byte padding + value) */
+                p = message_extend_fields(m, 8, 4 + 4 + 8, false);
+                if (!p)
+                        return -ENOMEM;
+
+                p[0] = (uint8_t) h;
+                p[1] = 1;
+                p[2] = 't';
+                p[3] = 0;
+                p[4] = 0;
+                p[5] = 0;
+                p[6] = 0;
+                p[7] = 0;
+
+                ((uint64_t*) p)[1] = x;
+        }
+
+        return 0;
+}
+
+static int message_append_reply_cookie(sd_bus_message *m, uint64_t cookie) {
+        assert(m);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m))
+                return message_append_field_uint64(m, BUS_MESSAGE_HEADER_REPLY_SERIAL, cookie);
+        else {
+                /* 64bit cookies are not supported on dbus1 */
+                if (cookie > 0xffffffffUL)
+                        return -EOPNOTSUPP;
+
+                return message_append_field_uint32(m, BUS_MESSAGE_HEADER_REPLY_SERIAL, (uint32_t) cookie);
+        }
+}
+
+int bus_message_from_header(
+                sd_bus *bus,
+                void *header,
+                size_t header_accessible,
+                void *footer,
+                size_t footer_accessible,
+                size_t message_size,
+                int *fds,
+                size_t n_fds,
+                const char *label,
+                size_t extra,
+                sd_bus_message **ret) {
+
+        _cleanup_free_ sd_bus_message *m = NULL;
+        struct bus_header *h;
+        size_t a, label_sz;
+
+        assert(bus);
+        assert(header || header_accessible <= 0);
+        assert(footer || footer_accessible <= 0);
+        assert(fds || n_fds <= 0);
+        assert(ret);
+
+        if (header_accessible < sizeof(struct bus_header))
+                return -EBADMSG;
+
+        if (header_accessible > message_size)
+                return -EBADMSG;
+        if (footer_accessible > message_size)
+                return -EBADMSG;
+
+        h = header;
+        if (!IN_SET(h->version, 1, 2))
+                return -EBADMSG;
+
+        if (h->type == _SD_BUS_MESSAGE_TYPE_INVALID)
+                return -EBADMSG;
+
+        if (!IN_SET(h->endian, BUS_LITTLE_ENDIAN, BUS_BIG_ENDIAN))
+                return -EBADMSG;
+
+        /* Note that we are happy with unknown flags in the flags header! */
+
+        a = ALIGN(sizeof(sd_bus_message)) + ALIGN(extra);
+
+        if (label) {
+                label_sz = strlen(label);
+                a += label_sz + 1;
+        }
+
+        m = malloc0(a);
+        if (!m)
+                return -ENOMEM;
+
+        m->sealed = true;
+        m->header = header;
+        m->header_accessible = header_accessible;
+        m->footer = footer;
+        m->footer_accessible = footer_accessible;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                size_t ws;
+
+                if (h->dbus2.cookie == 0)
+                        return -EBADMSG;
+
+                /* dbus2 derives the sizes from the message size and
+                the offset table at the end, since it is formatted as
+                gvariant "yyyyuta{tv}v". Since the message itself is a
+                structure with precisely to variable sized entries,
+                there's only one offset in the table, which marks the
+                end of the fields array. */
+
+                ws = bus_gvariant_determine_word_size(message_size, 0);
+                if (footer_accessible < ws)
+                        return -EBADMSG;
+
+                m->fields_size = bus_gvariant_read_word_le((uint8_t*) footer + footer_accessible - ws, ws);
+                if (ALIGN8(m->fields_size) > message_size - ws)
+                        return -EBADMSG;
+                if (m->fields_size < sizeof(struct bus_header))
+                        return -EBADMSG;
+
+                m->fields_size -= sizeof(struct bus_header);
+                m->body_size = message_size - (sizeof(struct bus_header) + ALIGN8(m->fields_size));
+        } else {
+                if (h->dbus1.serial == 0)
+                        return -EBADMSG;
+
+                /* dbus1 has the sizes in the header */
+                m->fields_size = BUS_MESSAGE_BSWAP32(m, h->dbus1.fields_size);
+                m->body_size = BUS_MESSAGE_BSWAP32(m, h->dbus1.body_size);
+
+                if (sizeof(struct bus_header) + ALIGN8(m->fields_size) + m->body_size != message_size)
+                        return -EBADMSG;
+        }
+
+        m->fds = fds;
+        m->n_fds = n_fds;
+
+        if (label) {
+                m->creds.label = (char*) m + ALIGN(sizeof(sd_bus_message)) + ALIGN(extra);
+                memcpy(m->creds.label, label, label_sz + 1);
+
+                m->creds.mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
+        }
+
+        m->n_ref = 1;
+        m->bus = sd_bus_ref(bus);
+
+        *ret = TAKE_PTR(m);
+
+        return 0;
+}
+
+int bus_message_from_malloc(
+                sd_bus *bus,
+                void *buffer,
+                size_t length,
+                int *fds,
+                size_t n_fds,
+                const char *label,
+                sd_bus_message **ret) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        size_t sz;
+        int r;
+
+        r = bus_message_from_header(
+                        bus,
+                        buffer, length, /* in this case the initial bytes and the final bytes are the same */
+                        buffer, length,
+                        length,
+                        fds, n_fds,
+                        label,
+                        0, &m);
+        if (r < 0)
+                return r;
+
+        sz = length - sizeof(struct bus_header) - ALIGN8(m->fields_size);
+        if (sz > 0) {
+                m->n_body_parts = 1;
+                m->body.data = (uint8_t*) buffer + sizeof(struct bus_header) + ALIGN8(m->fields_size);
+                m->body.size = sz;
+                m->body.sealed = true;
+                m->body.memfd = -1;
+        }
+
+        m->n_iovec = 1;
+        m->iovec = m->iovec_fixed;
+        m->iovec[0] = IOVEC_MAKE(buffer, length);
+
+        r = bus_message_parse_fields(m);
+        if (r < 0)
+                return r;
+
+        /* We take possession of the memory and fds now */
+        m->free_header = true;
+        m->free_fds = true;
+
+        *ret = TAKE_PTR(m);
+        return 0;
+}
+
+_public_ int sd_bus_message_new(
+                sd_bus *bus,
+                sd_bus_message **m,
+                uint8_t type) {
+
+        assert_return(bus, -ENOTCONN);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(m, -EINVAL);
+        /* Creation of messages with _SD_BUS_MESSAGE_TYPE_INVALID is allowed. */
+        assert_return(type < _SD_BUS_MESSAGE_TYPE_MAX, -EINVAL);
+
+        sd_bus_message *t = malloc0(ALIGN(sizeof(sd_bus_message)) + sizeof(struct bus_header));
+        if (!t)
+                return -ENOMEM;
+
+        t->n_ref = 1;
+        t->bus = sd_bus_ref(bus);
+        t->header = (struct bus_header*) ((uint8_t*) t + ALIGN(sizeof(struct sd_bus_message)));
+        t->header->endian = BUS_NATIVE_ENDIAN;
+        t->header->type = type;
+        t->header->version = bus->message_version;
+        t->allow_fds = bus->can_fds || !IN_SET(bus->state, BUS_HELLO, BUS_RUNNING);
+        t->root_container.need_offsets = BUS_MESSAGE_IS_GVARIANT(t);
+
+        if (bus->allow_interactive_authorization)
+                t->header->flags |= BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION;
+
+        *m = t;
+        return 0;
+}
+
+_public_ int sd_bus_message_new_signal(
+                sd_bus *bus,
+                sd_bus_message **m,
+                const char *path,
+                const char *interface,
+                const char *member) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert_return(bus, -ENOTCONN);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(interface_name_is_valid(interface), -EINVAL);
+        assert_return(member_name_is_valid(member), -EINVAL);
+        assert_return(m, -EINVAL);
+
+        r = sd_bus_message_new(bus, &t, SD_BUS_MESSAGE_SIGNAL);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        t->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_PATH, SD_BUS_TYPE_OBJECT_PATH, path, &t->path);
+        if (r < 0)
+                return r;
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_INTERFACE, SD_BUS_TYPE_STRING, interface, &t->interface);
+        if (r < 0)
+                return r;
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_MEMBER, SD_BUS_TYPE_STRING, member, &t->member);
+        if (r < 0)
+                return r;
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ int sd_bus_message_new_method_call(
+                sd_bus *bus,
+                sd_bus_message **m,
+                const char *destination,
+                const char *path,
+                const char *interface,
+                const char *member) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert_return(bus, -ENOTCONN);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(!destination || service_name_is_valid(destination), -EINVAL);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!interface || interface_name_is_valid(interface), -EINVAL);
+        assert_return(member_name_is_valid(member), -EINVAL);
+        assert_return(m, -EINVAL);
+
+        r = sd_bus_message_new(bus, &t, SD_BUS_MESSAGE_METHOD_CALL);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_PATH, SD_BUS_TYPE_OBJECT_PATH, path, &t->path);
+        if (r < 0)
+                return r;
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_MEMBER, SD_BUS_TYPE_STRING, member, &t->member);
+        if (r < 0)
+                return r;
+
+        if (interface) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_INTERFACE, SD_BUS_TYPE_STRING, interface, &t->interface);
+                if (r < 0)
+                        return r;
+        }
+
+        if (destination) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &t->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+static int message_new_reply(
+                sd_bus_message *call,
+                uint8_t type,
+                sd_bus_message **m) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        uint64_t cookie;
+        int r;
+
+        assert_return(call, -EINVAL);
+        assert_return(call->sealed, -EPERM);
+        assert_return(call->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(call->bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(m, -EINVAL);
+
+        cookie = BUS_MESSAGE_COOKIE(call);
+        if (cookie == 0)
+                return -EOPNOTSUPP;
+
+        r = sd_bus_message_new(call->bus, &t, type);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        t->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+        t->reply_cookie = cookie;
+        r = message_append_reply_cookie(t, t->reply_cookie);
+        if (r < 0)
+                return r;
+
+        if (call->sender) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, call->sender, &t->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        t->dont_send = !!(call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED);
+        t->enforced_reply_signature = call->enforced_reply_signature;
+
+        /* let's copy the sensitive flag over. Let's do that as a safety precaution to keep a transaction
+         * wholly sensitive if already the incoming message was sensitive. This is particularly useful when a
+         * vtable record sets the SD_BUS_VTABLE_SENSITIVE flag on a method call, since this means it applies
+         * to both the message call and the reply. */
+        t->sensitive = call->sensitive;
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ int sd_bus_message_new_method_return(
+                sd_bus_message *call,
+                sd_bus_message **m) {
+
+        return message_new_reply(call, SD_BUS_MESSAGE_METHOD_RETURN, m);
+}
+
+_public_ int sd_bus_message_new_method_error(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                const sd_bus_error *e) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert_return(sd_bus_error_is_set(e), -EINVAL);
+        assert_return(m, -EINVAL);
+
+        r = message_new_reply(call, SD_BUS_MESSAGE_METHOD_ERROR, &t);
+        if (r < 0)
+                return r;
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, e->name, &t->error.name);
+        if (r < 0)
+                return r;
+
+        if (e->message) {
+                r = message_append_basic(t, SD_BUS_TYPE_STRING, e->message, (const void**) &t->error.message);
+                if (r < 0)
+                        return r;
+        }
+
+        t->error._need_free = -1;
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ int sd_bus_message_new_method_errorf(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                const char *name,
+                const char *format,
+                ...) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        va_list ap;
+
+        assert_return(name, -EINVAL);
+        assert_return(m, -EINVAL);
+
+        va_start(ap, format);
+        bus_error_setfv(&error, name, format, ap);
+        va_end(ap);
+
+        return sd_bus_message_new_method_error(call, m, &error);
+}
+
+_public_ int sd_bus_message_new_method_errno(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                int error,
+                const sd_bus_error *p) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
+
+        if (sd_bus_error_is_set(p))
+                return sd_bus_message_new_method_error(call, m, p);
+
+        sd_bus_error_set_errno(&berror, error);
+
+        return sd_bus_message_new_method_error(call, m, &berror);
+}
+
+_public_ int sd_bus_message_new_method_errnof(
+                sd_bus_message *call,
+                sd_bus_message **m,
+                int error,
+                const char *format,
+                ...) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error berror = SD_BUS_ERROR_NULL;
+        va_list ap;
+
+        va_start(ap, format);
+        sd_bus_error_set_errnofv(&berror, error, format, ap);
+        va_end(ap);
+
+        return sd_bus_message_new_method_error(call, m, &berror);
+}
+
+void bus_message_set_sender_local(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus.Local";
+        m->creds.well_known_names_local = true;
+        m->creds.mask |= (SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES) & bus->creds_mask;
+}
+
+void bus_message_set_sender_driver(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus";
+        m->creds.well_known_names_driver = true;
+        m->creds.mask |= (SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES) & bus->creds_mask;
+}
+
+int bus_message_new_synthetic_error(
+                sd_bus *bus,
+                uint64_t cookie,
+                const sd_bus_error *e,
+                sd_bus_message **m) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *t = NULL;
+        int r;
+
+        assert(bus);
+        assert(sd_bus_error_is_set(e));
+        assert(m);
+
+        r = sd_bus_message_new(bus, &t, SD_BUS_MESSAGE_METHOD_ERROR);
+        if (r < 0)
+                return -ENOMEM;
+
+        assert(t);
+
+        t->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+        t->reply_cookie = cookie;
+
+        r = message_append_reply_cookie(t, t->reply_cookie);
+        if (r < 0)
+                return r;
+
+        if (bus && bus->unique_name) {
+                r = message_append_field_string(t, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, bus->unique_name, &t->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        r = message_append_field_string(t, BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, e->name, &t->error.name);
+        if (r < 0)
+                return r;
+
+        if (e->message) {
+                r = message_append_basic(t, SD_BUS_TYPE_STRING, e->message, (const void**) &t->error.message);
+                if (r < 0)
+                        return r;
+        }
+
+        t->error._need_free = -1;
+
+        bus_message_set_sender_driver(bus, t);
+
+        *m = TAKE_PTR(t);
+        return 0;
+}
+
+_public_ sd_bus_message* sd_bus_message_ref(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        /* We are fine if this message so far was either explicitly reffed or not reffed but queued into at
+         * least one bus connection object. */
+        assert(m->n_ref > 0 || m->n_queued > 0);
+
+        m->n_ref++;
+
+        /* Each user reference to a bus message shall also be considered a ref on the bus */
+        sd_bus_ref(m->bus);
+        return m;
+}
+
+_public_ sd_bus_message* sd_bus_message_unref(sd_bus_message *m) {
+        if (!m)
+                return NULL;
+
+        assert(m->n_ref > 0);
+
+        sd_bus_unref(m->bus); /* Each regular ref is also a ref on the bus connection. Let's hence drop it
+                               * here. Note we have to do this before decrementing our own n_ref here, since
+                               * otherwise, if this message is currently queued sd_bus_unref() might call
+                               * bus_message_unref_queued() for this which might then destroy the message
+                               * while we are still processing it. */
+        m->n_ref--;
+
+        if (m->n_ref > 0 || m->n_queued > 0)
+                return NULL;
+
+        /* Unset the bus field if neither the user has a reference nor this message is queued. We are careful
+         * to reset the field only after the last reference to the bus is dropped, after all we might keep
+         * multiple references to the bus, once for each reference kept on ourselves. */
+        m->bus = NULL;
+
+        return message_free(m);
+}
+
+sd_bus_message* bus_message_ref_queued(sd_bus_message *m, sd_bus *bus) {
+        if (!m)
+                return NULL;
+
+        /* If this is a different bus than the message is associated with, then implicitly turn this into a
+         * regular reference. This means that you can create a memory leak by enqueuing a message generated
+         * on one bus onto another at the same time as enqueueing a message from the second one on the first,
+         * as we'll not detect the cyclic references there. */
+        if (bus != m->bus)
+                return sd_bus_message_ref(m);
+
+        assert(m->n_ref > 0 || m->n_queued > 0);
+        m->n_queued++;
+
+        return m;
+}
+
+sd_bus_message* bus_message_unref_queued(sd_bus_message *m, sd_bus *bus) {
+        if (!m)
+                return NULL;
+
+        if (bus != m->bus)
+                return sd_bus_message_unref(m);
+
+        assert(m->n_queued > 0);
+        m->n_queued--;
+
+        if (m->n_ref > 0 || m->n_queued > 0)
+                return NULL;
+
+        m->bus = NULL;
+
+        return message_free(m);
+}
+
+_public_ int sd_bus_message_get_type(sd_bus_message *m, uint8_t *type) {
+        assert_return(m, -EINVAL);
+        assert_return(type, -EINVAL);
+
+        *type = m->header->type;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_cookie(sd_bus_message *m, uint64_t *cookie) {
+        uint64_t c;
+
+        assert_return(m, -EINVAL);
+        assert_return(cookie, -EINVAL);
+
+        c = BUS_MESSAGE_COOKIE(m);
+        if (c == 0)
+                return -ENODATA;
+
+        *cookie = BUS_MESSAGE_COOKIE(m);
+        return 0;
+}
+
+_public_ int sd_bus_message_get_reply_cookie(sd_bus_message *m, uint64_t *cookie) {
+        assert_return(m, -EINVAL);
+        assert_return(cookie, -EINVAL);
+
+        if (m->reply_cookie == 0)
+                return -ENODATA;
+
+        *cookie = m->reply_cookie;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_expect_reply(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return m->header->type == SD_BUS_MESSAGE_METHOD_CALL &&
+                !(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED);
+}
+
+_public_ int sd_bus_message_get_auto_start(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return !(m->header->flags & BUS_MESSAGE_NO_AUTO_START);
+}
+
+_public_ int sd_bus_message_get_allow_interactive_authorization(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return m->header->type == SD_BUS_MESSAGE_METHOD_CALL &&
+                (m->header->flags & BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION);
+}
+
+_public_ const char *sd_bus_message_get_path(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->path;
+}
+
+_public_ const char *sd_bus_message_get_interface(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->interface;
+}
+
+_public_ const char *sd_bus_message_get_member(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->member;
+}
+
+_public_ const char *sd_bus_message_get_destination(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->destination;
+}
+
+_public_ const char *sd_bus_message_get_sender(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->sender;
+}
+
+_public_ const sd_bus_error *sd_bus_message_get_error(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        if (!sd_bus_error_is_set(&m->error))
+                return NULL;
+
+        return &m->error;
+}
+
+_public_ int sd_bus_message_get_monotonic_usec(sd_bus_message *m, uint64_t *usec) {
+        assert_return(m, -EINVAL);
+        assert_return(usec, -EINVAL);
+
+        if (m->monotonic <= 0)
+                return -ENODATA;
+
+        *usec = m->monotonic;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_realtime_usec(sd_bus_message *m, uint64_t *usec) {
+        assert_return(m, -EINVAL);
+        assert_return(usec, -EINVAL);
+
+        if (m->realtime <= 0)
+                return -ENODATA;
+
+        *usec = m->realtime;
+        return 0;
+}
+
+_public_ int sd_bus_message_get_seqnum(sd_bus_message *m, uint64_t *seqnum) {
+        assert_return(m, -EINVAL);
+        assert_return(seqnum, -EINVAL);
+
+        if (m->seqnum <= 0)
+                return -ENODATA;
+
+        *seqnum = m->seqnum;
+        return 0;
+}
+
+_public_ sd_bus_creds *sd_bus_message_get_creds(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        if (m->creds.mask == 0)
+                return NULL;
+
+        return &m->creds;
+}
+
+_public_ int sd_bus_message_is_signal(
+                sd_bus_message *m,
+                const char *interface,
+                const char *member) {
+
+        assert_return(m, -EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_SIGNAL)
+                return 0;
+
+        if (interface && !streq_ptr(m->interface, interface))
+                return 0;
+
+        if (member && !streq_ptr(m->member, member))
+                return 0;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_is_method_call(
+                sd_bus_message *m,
+                const char *interface,
+                const char *member) {
+
+        assert_return(m, -EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 0;
+
+        if (interface && !streq_ptr(m->interface, interface))
+                return 0;
+
+        if (member && !streq_ptr(m->member, member))
+                return 0;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_is_method_error(sd_bus_message *m, const char *name) {
+        assert_return(m, -EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_ERROR)
+                return 0;
+
+        if (name && !streq_ptr(m->error.name, name))
+                return 0;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_set_expect_reply(sd_bus_message *m, int b) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EPERM);
+
+        SET_FLAG(m->header->flags, BUS_MESSAGE_NO_REPLY_EXPECTED, !b);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_set_auto_start(sd_bus_message *m, int b) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        SET_FLAG(m->header->flags, BUS_MESSAGE_NO_AUTO_START, !b);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_set_allow_interactive_authorization(sd_bus_message *m, int b) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        SET_FLAG(m->header->flags, BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION, b);
+
+        return 0;
+}
+
+struct bus_body_part *message_append_part(sd_bus_message *m) {
+        struct bus_body_part *part;
+
+        assert(m);
+
+        if (m->poisoned)
+                return NULL;
+
+        if (m->n_body_parts <= 0) {
+                part = &m->body;
+                zero(*part);
+        } else {
+                assert(m->body_end);
+
+                part = new0(struct bus_body_part, 1);
+                if (!part) {
+                        m->poisoned = true;
+                        return NULL;
+                }
+
+                m->body_end->next = part;
+        }
+
+        part->memfd = -1;
+        m->body_end = part;
+        m->n_body_parts++;
+
+        return part;
+}
+
+static void part_zero(struct bus_body_part *part, size_t sz) {
+        assert(part);
+        assert(sz > 0);
+        assert(sz < 8);
+
+        /* All other fields can be left in their defaults */
+        assert(!part->data);
+        assert(part->memfd < 0);
+
+        part->size = sz;
+        part->is_zero = true;
+        part->sealed = true;
+}
+
+static int part_make_space(
+                struct sd_bus_message *m,
+                struct bus_body_part *part,
+                size_t sz,
+                void **q) {
+
+        void *n;
+
+        assert(m);
+        assert(part);
+        assert(!part->sealed);
+
+        if (m->poisoned)
+                return -ENOMEM;
+
+        if (part->allocated == 0 || sz > part->allocated) {
+                size_t new_allocated;
+
+                new_allocated = sz > 0 ? 2 * sz : 64;
+                n = realloc(part->data, new_allocated);
+                if (!n) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+
+                part->data = n;
+                part->allocated = new_allocated;
+                part->free_this = true;
+        }
+
+        if (q)
+                *q = part->data ? (uint8_t*) part->data + part->size : NULL;
+
+        part->size = sz;
+        return 0;
+}
+
+static int message_add_offset(sd_bus_message *m, size_t offset) {
+        struct bus_container *c;
+
+        assert(m);
+        assert(BUS_MESSAGE_IS_GVARIANT(m));
+
+        /* Add offset to current container, unless this is the first
+         * item in it, which will have the 0 offset, which we can
+         * ignore. */
+        c = message_get_last_container(m);
+
+        if (!c->need_offsets)
+                return 0;
+
+        if (!GREEDY_REALLOC(c->offsets, c->offsets_allocated, c->n_offsets + 1))
+                return -ENOMEM;
+
+        c->offsets[c->n_offsets++] = offset;
+        return 0;
+}
+
+static void message_extend_containers(sd_bus_message *m, size_t expand) {
+        assert(m);
+
+        if (expand <= 0)
+                return;
+
+        if (m->n_containers <= 0)
+                return;
+
+        /* Update counters */
+        for (struct bus_container *c = m->containers; c < m->containers + m->n_containers; c++)
+                if (c->array_size)
+                        *c->array_size += expand;
+}
+
+static void *message_extend_body(
+                sd_bus_message *m,
+                size_t align,
+                size_t sz,
+                bool add_offset,
+                bool force_inline) {
+
+        size_t start_body, end_body, padding, added;
+        void *p;
+        int r;
+
+        assert(m);
+        assert(align > 0);
+        assert(!m->sealed);
+
+        if (m->poisoned)
+                return NULL;
+
+        start_body = ALIGN_TO((size_t) m->body_size, align);
+        end_body = start_body + sz;
+
+        padding = start_body - m->body_size;
+        added = padding + sz;
+
+        /* Check for 32bit overflows */
+        if (end_body > (size_t) ((uint32_t) -1) ||
+            end_body < start_body) {
+                m->poisoned = true;
+                return NULL;
+        }
+
+        if (added > 0) {
+                struct bus_body_part *part = NULL;
+                bool add_new_part;
+
+                add_new_part =
+                        m->n_body_parts <= 0 ||
+                        m->body_end->sealed ||
+                        (padding != ALIGN_TO(m->body_end->size, align) - m->body_end->size) ||
+                        (force_inline && m->body_end->size > MEMFD_MIN_SIZE);
+                        /* If this must be an inlined extension, let's create a new part if
+                         * the previous part is large enough to be inlined. */
+
+                if (add_new_part) {
+                        if (padding > 0) {
+                                part = message_append_part(m);
+                                if (!part)
+                                        return NULL;
+
+                                part_zero(part, padding);
+                        }
+
+                        part = message_append_part(m);
+                        if (!part)
+                                return NULL;
+
+                        r = part_make_space(m, part, sz, &p);
+                        if (r < 0)
+                                return NULL;
+                } else {
+                        void *op;
+                        size_t os, start_part, end_part;
+
+                        part = m->body_end;
+                        op = part->data;
+                        os = part->size;
+
+                        start_part = ALIGN_TO(part->size, align);
+                        end_part = start_part + sz;
+
+                        r = part_make_space(m, part, end_part, &p);
+                        if (r < 0)
+                                return NULL;
+
+                        if (padding > 0) {
+                                memzero(p, padding);
+                                p = (uint8_t*) p + padding;
+                        }
+
+                        /* Readjust pointers */
+                        if (m->n_containers > 0)
+                                for (struct bus_container *c = m->containers; c < m->containers + m->n_containers; c++)
+                                        c->array_size = adjust_pointer(c->array_size, op, os, part->data);
+
+                        m->error.message = (const char*) adjust_pointer(m->error.message, op, os, part->data);
+                }
+        } else
+                /* Return something that is not NULL and is aligned */
+                p = (uint8_t*) align;
+
+        m->body_size = end_body;
+        message_extend_containers(m, added);
+
+        if (add_offset) {
+                r = message_add_offset(m, end_body);
+                if (r < 0) {
+                        m->poisoned = true;
+                        return NULL;
+                }
+        }
+
+        return p;
+}
+
+static int message_push_fd(sd_bus_message *m, int fd) {
+        int *f, copy;
+
+        assert(m);
+
+        if (fd < 0)
+                return -EINVAL;
+
+        if (!m->allow_fds)
+                return -EOPNOTSUPP;
+
+        copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+        if (copy < 0)
+                return -errno;
+
+        f = reallocarray(m->fds, sizeof(int), m->n_fds + 1);
+        if (!f) {
+                m->poisoned = true;
+                safe_close(copy);
+                return -ENOMEM;
+        }
+
+        m->fds = f;
+        m->fds[m->n_fds] = copy;
+        m->free_fds = true;
+
+        return copy;
+}
+
+int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored) {
+        _cleanup_close_ int fd = -1;
+        struct bus_container *c;
+        ssize_t align, sz;
+        void *a;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_basic(type), -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        c = message_get_last_container(m);
+
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != type)
+                        return -ENXIO;
+        } else {
+                char *e;
+
+                /* Maybe we can append to the signature? But only if this is the top-level container */
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(type), NULL);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                uint8_t u8;
+                uint32_t u32;
+
+                switch (type) {
+
+                case SD_BUS_TYPE_SIGNATURE:
+                case SD_BUS_TYPE_STRING:
+                        p = strempty(p);
+
+                        _fallthrough_;
+                case SD_BUS_TYPE_OBJECT_PATH:
+                        if (!p)
+                                return -EINVAL;
+
+                        align = 1;
+                        sz = strlen(p) + 1;
+                        break;
+
+                case SD_BUS_TYPE_BOOLEAN:
+
+                        u8 = p && *(int*) p;
+                        p = &u8;
+
+                        align = sz = 1;
+                        break;
+
+                case SD_BUS_TYPE_UNIX_FD:
+
+                        if (!p)
+                                return -EINVAL;
+
+                        fd = message_push_fd(m, *(int*) p);
+                        if (fd < 0)
+                                return fd;
+
+                        u32 = m->n_fds;
+                        p = &u32;
+
+                        align = sz = 4;
+                        break;
+
+                default:
+                        align = bus_gvariant_get_alignment(CHAR_TO_STR(type));
+                        sz = bus_gvariant_get_size(CHAR_TO_STR(type));
+                        break;
+                }
+
+                assert(align > 0);
+                assert(sz > 0);
+
+                a = message_extend_body(m, align, sz, true, false);
+                if (!a)
+                        return -ENOMEM;
+
+                memcpy(a, p, sz);
+
+                if (stored)
+                        *stored = (const uint8_t*) a;
+
+        } else {
+                uint32_t u32;
+
+                switch (type) {
+
+                case SD_BUS_TYPE_STRING:
+                        /* To make things easy we'll serialize a NULL string
+                         * into the empty string */
+                        p = strempty(p);
+
+                        _fallthrough_;
+                case SD_BUS_TYPE_OBJECT_PATH:
+
+                        if (!p)
+                                return -EINVAL;
+
+                        align = 4;
+                        sz = 4 + strlen(p) + 1;
+                        break;
+
+                case SD_BUS_TYPE_SIGNATURE:
+
+                        p = strempty(p);
+
+                        align = 1;
+                        sz = 1 + strlen(p) + 1;
+                        break;
+
+                case SD_BUS_TYPE_BOOLEAN:
+
+                        u32 = p && *(int*) p;
+                        p = &u32;
+
+                        align = sz = 4;
+                        break;
+
+                case SD_BUS_TYPE_UNIX_FD:
+
+                        if (!p)
+                                return -EINVAL;
+
+                        fd = message_push_fd(m, *(int*) p);
+                        if (fd < 0)
+                                return fd;
+
+                        u32 = m->n_fds;
+                        p = &u32;
+
+                        align = sz = 4;
+                        break;
+
+                default:
+                        align = bus_type_get_alignment(type);
+                        sz = bus_type_get_size(type);
+                        break;
+                }
+
+                assert(align > 0);
+                assert(sz > 0);
+
+                a = message_extend_body(m, align, sz, false, false);
+                if (!a)
+                        return -ENOMEM;
+
+                if (IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH)) {
+                        *(uint32_t*) a = sz - 5;
+                        memcpy((uint8_t*) a + 4, p, sz - 4);
+
+                        if (stored)
+                                *stored = (const uint8_t*) a + 4;
+
+                } else if (type == SD_BUS_TYPE_SIGNATURE) {
+                        *(uint8_t*) a = sz - 2;
+                        memcpy((uint8_t*) a + 1, p, sz - 1);
+
+                        if (stored)
+                                *stored = (const uint8_t*) a + 1;
+                } else {
+                        memcpy(a, p, sz);
+
+                        if (stored)
+                                *stored = a;
+                }
+        }
+
+        if (type == SD_BUS_TYPE_UNIX_FD)
+                m->n_fds++;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        fd = -1;
+        return 0;
+}
+
+_public_ int sd_bus_message_append_basic(sd_bus_message *m, char type, const void *p) {
+        return message_append_basic(m, type, p, NULL);
+}
+
+_public_ int sd_bus_message_append_string_space(
+                sd_bus_message *m,
+                size_t size,
+                char **s) {
+
+        struct bus_container *c;
+        void *a;
+
+        assert_return(m, -EINVAL);
+        assert_return(s, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        c = message_get_last_container(m);
+
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_STRING)
+                        return -ENXIO;
+        } else {
+                char *e;
+
+                /* Maybe we can append to the signature? But only if this is the top-level container */
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRING), NULL);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                a = message_extend_body(m, 1, size + 1, true, false);
+                if (!a)
+                        return -ENOMEM;
+
+                *s = a;
+        } else {
+                a = message_extend_body(m, 4, 4 + size + 1, false, false);
+                if (!a)
+                        return -ENOMEM;
+
+                *(uint32_t*) a = size;
+                *s = (char*) a + 4;
+        }
+
+        (*s)[size] = 0;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_string_iovec(
+                sd_bus_message *m,
+                const struct iovec *iov,
+                unsigned n /* should be size_t, but is API now… 😞 */) {
+
+        size_t size;
+        unsigned i;
+        char *p;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(iov || n == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        size = IOVEC_TOTAL_SIZE(iov, n);
+
+        r = sd_bus_message_append_string_space(m, size, &p);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < n; i++) {
+
+                if (iov[i].iov_base)
+                        memcpy(p, iov[i].iov_base, iov[i].iov_len);
+                else
+                        memset(p, ' ', iov[i].iov_len);
+
+                p += iov[i].iov_len;
+        }
+
+        return 0;
+}
+
+static int bus_message_open_array(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                uint32_t **array_size,
+                size_t *begin,
+                bool *need_offsets) {
+
+        unsigned nindex;
+        int alignment, r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(array_size);
+        assert(begin);
+        assert(need_offsets);
+
+        if (!signature_is_single(contents, true))
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+
+                /* Verify the existing signature */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_ARRAY)
+                        return -ENXIO;
+
+                if (!startswith(c->signature + c->index + 1, contents))
+                        return -ENXIO;
+
+                nindex = c->index + 1 + strlen(contents);
+        } else {
+                char *e;
+
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                /* Extend the existing signature */
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_ARRAY), contents, NULL);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+
+                nindex = e - c->signature;
+        }
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                alignment = bus_gvariant_get_alignment(contents);
+                if (alignment < 0)
+                        return alignment;
+
+                /* Add alignment padding and add to offset list */
+                if (!message_extend_body(m, alignment, 0, false, false))
+                        return -ENOMEM;
+
+                r = bus_gvariant_is_fixed_size(contents);
+                if (r < 0)
+                        return r;
+
+                *begin = m->body_size;
+                *need_offsets = r == 0;
+        } else {
+                void *a, *op;
+                size_t os;
+                struct bus_body_part *o;
+
+                alignment = bus_type_get_alignment(contents[0]);
+                if (alignment < 0)
+                        return alignment;
+
+                a = message_extend_body(m, 4, 4, false, false);
+                if (!a)
+                        return -ENOMEM;
+
+                o = m->body_end;
+                op = m->body_end->data;
+                os = m->body_end->size;
+
+                /* Add alignment between size and first element */
+                if (!message_extend_body(m, alignment, 0, false, false))
+                        return -ENOMEM;
+
+                /* location of array size might have changed so let's readjust a */
+                if (o == m->body_end)
+                        a = adjust_pointer(a, op, os, m->body_end->data);
+
+                *(uint32_t*) a = 0;
+                *array_size = a;
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+static int bus_message_open_variant(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents) {
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_single(contents, false))
+                return -EINVAL;
+
+        if (*contents == SD_BUS_TYPE_DICT_ENTRY_BEGIN)
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+
+                if (c->signature[c->index] != SD_BUS_TYPE_VARIANT)
+                        return -ENXIO;
+
+        } else {
+                char *e;
+
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_VARIANT), NULL);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                /* Variants are always aligned to 8 */
+
+                if (!message_extend_body(m, 8, 0, false, false))
+                        return -ENOMEM;
+
+        } else {
+                size_t l;
+                void *a;
+
+                l = strlen(contents);
+                a = message_extend_body(m, 1, 1 + l + 1, false, false);
+                if (!a)
+                        return -ENOMEM;
+
+                *(uint8_t*) a = l;
+                memcpy((uint8_t*) a + 1, contents, l + 1);
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 0;
+}
+
+static int bus_message_open_struct(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *begin,
+                bool *need_offsets) {
+
+        size_t nindex;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(begin);
+        assert(need_offsets);
+
+        if (!signature_is_valid(contents, false))
+                return -EINVAL;
+
+        if (c->signature && c->signature[c->index]) {
+                size_t l;
+
+                l = strlen(contents);
+
+                if (c->signature[c->index] != SD_BUS_TYPE_STRUCT_BEGIN ||
+                    !startswith(c->signature + c->index + 1, contents) ||
+                    c->signature[c->index + 1 + l] != SD_BUS_TYPE_STRUCT_END)
+                        return -ENXIO;
+
+                nindex = c->index + 1 + l + 1;
+        } else {
+                char *e;
+
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRUCT_BEGIN), contents, CHAR_TO_STR(SD_BUS_TYPE_STRUCT_END), NULL);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+
+                nindex = e - c->signature;
+        }
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                int alignment;
+
+                alignment = bus_gvariant_get_alignment(contents);
+                if (alignment < 0)
+                        return alignment;
+
+                if (!message_extend_body(m, alignment, 0, false, false))
+                        return -ENOMEM;
+
+                r = bus_gvariant_is_fixed_size(contents);
+                if (r < 0)
+                        return r;
+
+                *begin = m->body_size;
+                *need_offsets = r == 0;
+        } else {
+                /* Align contents to 8 byte boundary */
+                if (!message_extend_body(m, 8, 0, false, false))
+                        return -ENOMEM;
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index = nindex;
+
+        return 0;
+}
+
+static int bus_message_open_dict_entry(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *begin,
+                bool *need_offsets) {
+
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(begin);
+        assert(need_offsets);
+
+        if (!signature_is_pair(contents))
+                return -EINVAL;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+
+        if (c->signature && c->signature[c->index]) {
+                size_t l;
+
+                l = strlen(contents);
+
+                if (c->signature[c->index] != SD_BUS_TYPE_DICT_ENTRY_BEGIN ||
+                    !startswith(c->signature + c->index + 1, contents) ||
+                    c->signature[c->index + 1 + l] != SD_BUS_TYPE_DICT_ENTRY_END)
+                        return -ENXIO;
+        } else
+                return -ENXIO;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                int alignment;
+
+                alignment = bus_gvariant_get_alignment(contents);
+                if (alignment < 0)
+                        return alignment;
+
+                if (!message_extend_body(m, alignment, 0, false, false))
+                        return -ENOMEM;
+
+                r = bus_gvariant_is_fixed_size(contents);
+                if (r < 0)
+                        return r;
+
+                *begin = m->body_size;
+                *need_offsets = r == 0;
+        } else {
+                /* Align contents to 8 byte boundary */
+                if (!message_extend_body(m, 8, 0, false, false))
+                        return -ENOMEM;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_open_container(
+                sd_bus_message *m,
+                char type,
+                const char *contents) {
+
+        struct bus_container *c;
+        uint32_t *array_size = NULL;
+        _cleanup_free_ char *signature = NULL;
+        size_t before, begin = 0;
+        bool need_offsets = false;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(contents, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        /* Make sure we have space for one more container */
+        if (!GREEDY_REALLOC(m->containers, m->containers_allocated, m->n_containers + 1)) {
+                m->poisoned = true;
+                return -ENOMEM;
+        }
+
+        c = message_get_last_container(m);
+
+        signature = strdup(contents);
+        if (!signature) {
+                m->poisoned = true;
+                return -ENOMEM;
+        }
+
+        /* Save old index in the parent container, in case we have to
+         * abort this container */
+        c->saved_index = c->index;
+        before = m->body_size;
+
+        if (type == SD_BUS_TYPE_ARRAY)
+                r = bus_message_open_array(m, c, contents, &array_size, &begin, &need_offsets);
+        else if (type == SD_BUS_TYPE_VARIANT)
+                r = bus_message_open_variant(m, c, contents);
+        else if (type == SD_BUS_TYPE_STRUCT)
+                r = bus_message_open_struct(m, c, contents, &begin, &need_offsets);
+        else if (type == SD_BUS_TYPE_DICT_ENTRY)
+                r = bus_message_open_dict_entry(m, c, contents, &begin, &need_offsets);
+        else
+                r = -EINVAL;
+        if (r < 0)
+                return r;
+
+        /* OK, let's fill it in */
+        m->containers[m->n_containers++] = (struct bus_container) {
+                .enclosing = type,
+                .signature = TAKE_PTR(signature),
+                .array_size = array_size,
+                .before = before,
+                .begin = begin,
+                .need_offsets = need_offsets,
+        };
+
+        return 0;
+}
+
+static int bus_message_close_array(sd_bus_message *m, struct bus_container *c) {
+
+        assert(m);
+        assert(c);
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m))
+                return 0;
+
+        if (c->need_offsets) {
+                size_t payload, sz, i;
+                uint8_t *a;
+
+                /* Variable-width arrays */
+
+                payload = c->n_offsets > 0 ? c->offsets[c->n_offsets-1] - c->begin : 0;
+                sz = bus_gvariant_determine_word_size(payload, c->n_offsets);
+
+                a = message_extend_body(m, 1, sz * c->n_offsets, true, false);
+                if (!a)
+                        return -ENOMEM;
+
+                for (i = 0; i < c->n_offsets; i++)
+                        bus_gvariant_write_word_le(a + sz*i, sz, c->offsets[i] - c->begin);
+        } else {
+                void *a;
+
+                /* Fixed-width or empty arrays */
+
+                a = message_extend_body(m, 1, 0, true, false); /* let's add offset to parent */
+                if (!a)
+                        return -ENOMEM;
+        }
+
+        return 0;
+}
+
+static int bus_message_close_variant(sd_bus_message *m, struct bus_container *c) {
+        uint8_t *a;
+        size_t l;
+
+        assert(m);
+        assert(c);
+        assert(c->signature);
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m))
+                return 0;
+
+        l = strlen(c->signature);
+
+        a = message_extend_body(m, 1, 1 + l, true, false);
+        if (!a)
+                return -ENOMEM;
+
+        a[0] = 0;
+        memcpy(a+1, c->signature, l);
+
+        return 0;
+}
+
+static int bus_message_close_struct(sd_bus_message *m, struct bus_container *c, bool add_offset) {
+        bool fixed_size = true;
+        size_t n_variable = 0;
+        unsigned i = 0;
+        const char *p;
+        uint8_t *a;
+        int r;
+
+        assert(m);
+        assert(c);
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m))
+                return 0;
+
+        p = strempty(c->signature);
+        while (*p != 0) {
+                size_t n;
+
+                r = signature_element_length(p, &n);
+                if (r < 0)
+                        return r;
+                else {
+                        char t[n+1];
+
+                        memcpy(t, p, n);
+                        t[n] = 0;
+
+                        r = bus_gvariant_is_fixed_size(t);
+                        if (r < 0)
+                                return r;
+                }
+
+                assert(!c->need_offsets || i <= c->n_offsets);
+
+                /* We need to add an offset for each item that has a
+                 * variable size and that is not the last one in the
+                 * list */
+                if (r == 0)
+                        fixed_size = false;
+                if (r == 0 && p[n] != 0)
+                        n_variable++;
+
+                i++;
+                p += n;
+        }
+
+        assert(!c->need_offsets || i == c->n_offsets);
+        assert(c->need_offsets || n_variable == 0);
+
+        if (isempty(c->signature)) {
+                /* The unary type is encoded as fixed 1 byte padding */
+                a = message_extend_body(m, 1, 1, add_offset, false);
+                if (!a)
+                        return -ENOMEM;
+
+                *a = 0;
+        } else if (n_variable <= 0) {
+                int alignment = 1;
+
+                /* Structures with fixed-size members only have to be
+                 * fixed-size themselves. But gvariant requires all fixed-size
+                 * elements to be sized a multiple of their alignment. Hence,
+                 * we must *always* add final padding after the last member so
+                 * the overall size of the structure is properly aligned. */
+                if (fixed_size)
+                        alignment = bus_gvariant_get_alignment(strempty(c->signature));
+
+                assert(alignment > 0);
+
+                a = message_extend_body(m, alignment, 0, add_offset, false);
+                if (!a)
+                        return -ENOMEM;
+        } else {
+                size_t sz;
+                unsigned j;
+
+                assert(c->offsets[c->n_offsets-1] == m->body_size);
+
+                sz = bus_gvariant_determine_word_size(m->body_size - c->begin, n_variable);
+
+                a = message_extend_body(m, 1, sz * n_variable, add_offset, false);
+                if (!a)
+                        return -ENOMEM;
+
+                p = strempty(c->signature);
+                for (i = 0, j = 0; i < c->n_offsets; i++) {
+                        unsigned k;
+                        size_t n;
+
+                        r = signature_element_length(p, &n);
+                        if (r < 0)
+                                return r;
+                        else {
+                                char t[n+1];
+
+                                memcpy(t, p, n);
+                                t[n] = 0;
+
+                                p += n;
+
+                                r = bus_gvariant_is_fixed_size(t);
+                                if (r < 0)
+                                        return r;
+                                if (r > 0 || p[0] == 0)
+                                        continue;
+                        }
+
+                        k = n_variable - 1 - j;
+
+                        bus_gvariant_write_word_le(a + k * sz, sz, c->offsets[i] - c->begin);
+
+                        j++;
+                }
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_close_container(sd_bus_message *m) {
+        struct bus_container *c;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->n_containers > 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        c = message_get_last_container(m);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                if (c->signature && c->signature[c->index] != 0)
+                        return -EINVAL;
+
+        m->n_containers--;
+
+        if (c->enclosing == SD_BUS_TYPE_ARRAY)
+                r = bus_message_close_array(m, c);
+        else if (c->enclosing == SD_BUS_TYPE_VARIANT)
+                r = bus_message_close_variant(m, c);
+        else if (IN_SET(c->enclosing, SD_BUS_TYPE_STRUCT, SD_BUS_TYPE_DICT_ENTRY))
+                r = bus_message_close_struct(m, c, true);
+        else
+                assert_not_reached("Unknown container type");
+
+        free(c->signature);
+        free(c->offsets);
+
+        return r;
+}
+
+typedef struct {
+        const char *types;
+        unsigned n_struct;
+        unsigned n_array;
+} TypeStack;
+
+static int type_stack_push(TypeStack *stack, unsigned max, unsigned *i, const char *types, unsigned n_struct, unsigned n_array) {
+        assert(stack);
+        assert(max > 0);
+
+        if (*i >= max)
+                return -EINVAL;
+
+        stack[*i].types = types;
+        stack[*i].n_struct = n_struct;
+        stack[*i].n_array = n_array;
+        (*i)++;
+
+        return 0;
+}
+
+static int type_stack_pop(TypeStack *stack, unsigned max, unsigned *i, const char **types, unsigned *n_struct, unsigned *n_array) {
+        assert(stack);
+        assert(max > 0);
+        assert(types);
+        assert(n_struct);
+        assert(n_array);
+
+        if (*i <= 0)
+                return 0;
+
+        (*i)--;
+        *types = stack[*i].types;
+        *n_struct = stack[*i].n_struct;
+        *n_array = stack[*i].n_array;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_appendv(
+                sd_bus_message *m,
+                const char *types,
+                va_list ap) {
+
+        unsigned n_array, n_struct;
+        TypeStack stack[BUS_CONTAINER_DEPTH];
+        unsigned stack_ptr = 0;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(types, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        n_array = (unsigned) -1;
+        n_struct = strlen(types);
+
+        for (;;) {
+                const char *t;
+
+                if (n_array == 0 || (n_array == (unsigned) -1 && n_struct == 0)) {
+                        r = type_stack_pop(stack, ELEMENTSOF(stack), &stack_ptr, &types, &n_struct, &n_array);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = sd_bus_message_close_container(m);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                t = types;
+                if (n_array != (unsigned) -1)
+                        n_array--;
+                else {
+                        types++;
+                        n_struct--;
+                }
+
+                switch (*t) {
+
+                case SD_BUS_TYPE_BYTE: {
+                        uint8_t x;
+
+                        x = (uint8_t) va_arg(ap, int);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                case SD_BUS_TYPE_UNIX_FD: {
+                        uint32_t x;
+
+                        /* We assume a boolean is the same as int32_t */
+                        assert_cc(sizeof(int32_t) == sizeof(int));
+
+                        x = va_arg(ap, uint32_t);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16: {
+                        uint16_t x;
+
+                        x = (uint16_t) va_arg(ap, int);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64: {
+                        uint64_t x;
+
+                        x = va_arg(ap, uint64_t);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_DOUBLE: {
+                        double x;
+
+                        x = va_arg(ap, double);
+                        r = sd_bus_message_append_basic(m, *t, &x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE: {
+                        const char *x;
+
+                        x = va_arg(ap, const char*);
+                        r = sd_bus_message_append_basic(m, *t, x);
+                        break;
+                }
+
+                case SD_BUS_TYPE_ARRAY: {
+                        size_t k;
+
+                        r = signature_element_length(t + 1, &k);
+                        if (r < 0)
+                                return r;
+
+                        {
+                                char s[k + 1];
+                                memcpy(s, t + 1, k);
+                                s[k] = 0;
+
+                                r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (n_array == (unsigned) -1) {
+                                types += k;
+                                n_struct -= k;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k;
+                        n_array = va_arg(ap, unsigned);
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_VARIANT: {
+                        const char *s;
+
+                        s = va_arg(ap, const char*);
+                        if (!s)
+                                return -EINVAL;
+
+                        r = sd_bus_message_open_container(m, SD_BUS_TYPE_VARIANT, s);
+                        if (r < 0)
+                                return r;
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = s;
+                        n_struct = strlen(s);
+                        n_array = (unsigned) -1;
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRUCT_BEGIN:
+                case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                        size_t k;
+
+                        r = signature_element_length(t, &k);
+                        if (r < 0)
+                                return r;
+
+                        {
+                                char s[k - 1];
+
+                                memcpy(s, t + 1, k - 2);
+                                s[k - 2] = 0;
+
+                                r = sd_bus_message_open_container(m, *t == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY, s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (n_array == (unsigned) -1) {
+                                types += k - 1;
+                                n_struct -= k - 1;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k - 2;
+                        n_array = (unsigned) -1;
+
+                        break;
+                }
+
+                default:
+                        r = -EINVAL;
+                }
+
+                if (r < 0)
+                        return r;
+        }
+
+        return 1;
+}
+
+_public_ int sd_bus_message_append(sd_bus_message *m, const char *types, ...) {
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_message_appendv(m, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_message_append_array_space(
+                sd_bus_message *m,
+                char type,
+                size_t size,
+                void **ptr) {
+
+        ssize_t align, sz;
+        void *a;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type) && type != SD_BUS_TYPE_BOOLEAN, -EINVAL);
+        assert_return(ptr || size == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        /* alignment and size of the trivial types (except bool) is
+         * identical for gvariant and dbus1 marshalling */
+        align = bus_type_get_alignment(type);
+        sz = bus_type_get_size(type);
+
+        assert_se(align > 0);
+        assert_se(sz > 0);
+
+        if (size % sz != 0)
+                return -EINVAL;
+
+        r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+        if (r < 0)
+                return r;
+
+        a = message_extend_body(m, align, size, false, false);
+        if (!a)
+                return -ENOMEM;
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        *ptr = a;
+        return 0;
+}
+
+_public_ int sd_bus_message_append_array(
+                sd_bus_message *m,
+                char type,
+                const void *ptr,
+                size_t size) {
+        int r;
+        void *p;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(ptr || size == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = sd_bus_message_append_array_space(m, type, size, &p);
+        if (r < 0)
+                return r;
+
+        memcpy_safe(p, ptr, size);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_array_iovec(
+                sd_bus_message *m,
+                char type,
+                const struct iovec *iov,
+                unsigned n /* should be size_t, but is API now… 😞 */) {
+
+        size_t size;
+        unsigned i;
+        void *p;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(iov || n == 0, -EINVAL);
+        assert_return(!m->poisoned, -ESTALE);
+
+        size = IOVEC_TOTAL_SIZE(iov, n);
+
+        r = sd_bus_message_append_array_space(m, type, size, &p);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < n; i++) {
+
+                if (iov[i].iov_base)
+                        memcpy(p, iov[i].iov_base, iov[i].iov_len);
+                else
+                        memzero(p, iov[i].iov_len);
+
+                p = (uint8_t*) p + iov[i].iov_len;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_array_memfd(
+                sd_bus_message *m,
+                char type,
+                int memfd,
+                uint64_t offset,
+                uint64_t size) {
+
+        _cleanup_close_ int copy_fd = -1;
+        struct bus_body_part *part;
+        ssize_t align, sz;
+        uint64_t real_size;
+        void *a;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(memfd >= 0, -EBADF);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(size > 0, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = memfd_set_sealed(memfd);
+        if (r < 0)
+                return r;
+
+        copy_fd = fcntl(memfd, F_DUPFD_CLOEXEC, 3);
+        if (copy_fd < 0)
+                return copy_fd;
+
+        r = memfd_get_size(memfd, &real_size);
+        if (r < 0)
+                return r;
+
+        if (offset == 0 && size == (uint64_t) -1)
+                size = real_size;
+        else if (offset + size > real_size)
+                return -EMSGSIZE;
+
+        align = bus_type_get_alignment(type);
+        sz = bus_type_get_size(type);
+
+        assert_se(align > 0);
+        assert_se(sz > 0);
+
+        if (offset % align != 0)
+                return -EINVAL;
+
+        if (size % sz != 0)
+                return -EINVAL;
+
+        if (size > (uint64_t) (uint32_t) -1)
+                return -EINVAL;
+
+        r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+        if (r < 0)
+                return r;
+
+        a = message_extend_body(m, align, 0, false, false);
+        if (!a)
+                return -ENOMEM;
+
+        part = message_append_part(m);
+        if (!part)
+                return -ENOMEM;
+
+        part->memfd = copy_fd;
+        part->memfd_offset = offset;
+        part->sealed = true;
+        part->size = size;
+        copy_fd = -1;
+
+        m->body_size += size;
+        message_extend_containers(m, size);
+
+        return sd_bus_message_close_container(m);
+}
+
+_public_ int sd_bus_message_append_string_memfd(
+                sd_bus_message *m,
+                int memfd,
+                uint64_t offset,
+                uint64_t size) {
+
+        _cleanup_close_ int copy_fd = -1;
+        struct bus_body_part *part;
+        struct bus_container *c;
+        uint64_t real_size;
+        void *a;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(memfd >= 0, -EBADF);
+        assert_return(size > 0, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = memfd_set_sealed(memfd);
+        if (r < 0)
+                return r;
+
+        copy_fd = fcntl(memfd, FD_CLOEXEC, 3);
+        if (copy_fd < 0)
+                return copy_fd;
+
+        r = memfd_get_size(memfd, &real_size);
+        if (r < 0)
+                return r;
+
+        if (offset == 0 && size == (uint64_t) -1)
+                size = real_size;
+        else if (offset + size > real_size)
+                return -EMSGSIZE;
+
+        /* We require this to be NUL terminated */
+        if (size == 0)
+                return -EINVAL;
+
+        if (size > (uint64_t) (uint32_t) -1)
+                return -EINVAL;
+
+        c = message_get_last_container(m);
+        if (c->signature && c->signature[c->index]) {
+                /* Container signature is already set */
+
+                if (c->signature[c->index] != SD_BUS_TYPE_STRING)
+                        return -ENXIO;
+        } else {
+                char *e;
+
+                /* Maybe we can append to the signature? But only if this is the top-level container */
+                if (c->enclosing != 0)
+                        return -ENXIO;
+
+                e = strextend(&c->signature, CHAR_TO_STR(SD_BUS_TYPE_STRING), NULL);
+                if (!e) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m)) {
+                a = message_extend_body(m, 4, 4, false, false);
+                if (!a)
+                        return -ENOMEM;
+
+                *(uint32_t*) a = size - 1;
+        }
+
+        part = message_append_part(m);
+        if (!part)
+                return -ENOMEM;
+
+        part->memfd = copy_fd;
+        part->memfd_offset = offset;
+        part->sealed = true;
+        part->size = size;
+        copy_fd = -1;
+
+        m->body_size += size;
+        message_extend_containers(m, size);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                r = message_add_offset(m, m->body_size);
+                if (r < 0) {
+                        m->poisoned = true;
+                        return -ENOMEM;
+                }
+        }
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 0;
+}
+
+_public_ int sd_bus_message_append_strv(sd_bus_message *m, char **l) {
+        char **i;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->poisoned, -ESTALE);
+
+        r = sd_bus_message_open_container(m, 'a', "s");
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, l) {
+                r = sd_bus_message_append_basic(m, 's', *i);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_message_close_container(m);
+}
+
+static int bus_message_close_header(sd_bus_message *m) {
+
+        assert(m);
+
+        /* The actual user data is finished now, we just complete the
+           variant and struct now (at least on gvariant). Remember
+           this position, so that during parsing we know where to
+           put the outer container end. */
+        m->user_body_size = m->body_size;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                const char *signature;
+                size_t sz, l;
+                void *d;
+
+                /* Add offset table to end of fields array */
+                if (m->n_header_offsets >= 1) {
+                        uint8_t *a;
+                        unsigned i;
+
+                        assert(m->fields_size == m->header_offsets[m->n_header_offsets-1]);
+
+                        sz = bus_gvariant_determine_word_size(m->fields_size, m->n_header_offsets);
+                        a = message_extend_fields(m, 1, sz * m->n_header_offsets, false);
+                        if (!a)
+                                return -ENOMEM;
+
+                        for (i = 0; i < m->n_header_offsets; i++)
+                                bus_gvariant_write_word_le(a + sz*i, sz, m->header_offsets[i]);
+                }
+
+                /* Add gvariant NUL byte plus signature to the end of
+                 * the body, followed by the final offset pointing to
+                 * the end of the fields array */
+
+                signature = strempty(m->root_container.signature);
+                l = strlen(signature);
+
+                sz = bus_gvariant_determine_word_size(sizeof(struct bus_header) + ALIGN8(m->fields_size) + m->body_size + 1 + l + 2, 1);
+                d = message_extend_body(m, 1, 1 + l + 2 + sz, false, true);
+                if (!d)
+                        return -ENOMEM;
+
+                *(uint8_t*) d = 0;
+                *((uint8_t*) d + 1) = SD_BUS_TYPE_STRUCT_BEGIN;
+                memcpy((uint8_t*) d + 2, signature, l);
+                *((uint8_t*) d + 1 + l + 1) = SD_BUS_TYPE_STRUCT_END;
+
+                bus_gvariant_write_word_le((uint8_t*) d + 1 + l + 2, sz, sizeof(struct bus_header) + m->fields_size);
+
+                m->footer = d;
+                m->footer_accessible = 1 + l + 2 + sz;
+        } else {
+                m->header->dbus1.fields_size = m->fields_size;
+                m->header->dbus1.body_size = m->body_size;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_seal(sd_bus_message *m, uint64_t cookie, uint64_t timeout_usec) {
+        struct bus_body_part *part;
+        size_t a;
+        unsigned i;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (m->sealed)
+                return -EPERM;
+
+        if (m->n_containers > 0)
+                return -EBADMSG;
+
+        if (m->poisoned)
+                return -ESTALE;
+
+        if (cookie > 0xffffffffULL &&
+            !BUS_MESSAGE_IS_GVARIANT(m))
+                return -EOPNOTSUPP;
+
+        /* In vtables the return signature of method calls is listed,
+         * let's check if they match if this is a response */
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_RETURN &&
+            m->enforced_reply_signature &&
+            !streq(strempty(m->root_container.signature), m->enforced_reply_signature))
+                return -ENOMSG;
+
+        /* If gvariant marshalling is used we need to close the body structure */
+        r = bus_message_close_struct(m, &m->root_container, false);
+        if (r < 0)
+                return r;
+
+        /* If there's a non-trivial signature set, then add it in
+         * here, but only on dbus1 */
+        if (!isempty(m->root_container.signature) && !BUS_MESSAGE_IS_GVARIANT(m)) {
+                r = message_append_field_signature(m, BUS_MESSAGE_HEADER_SIGNATURE, m->root_container.signature, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        if (m->n_fds > 0) {
+                r = message_append_field_uint32(m, BUS_MESSAGE_HEADER_UNIX_FDS, m->n_fds);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bus_message_close_header(m);
+        if (r < 0)
+                return r;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m))
+                m->header->dbus2.cookie = cookie;
+        else
+                m->header->dbus1.serial = (uint32_t) cookie;
+
+        m->timeout = m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED ? 0 : timeout_usec;
+
+        /* Add padding at the end of the fields part, since we know
+         * the body needs to start at an 8 byte alignment. We made
+         * sure we allocated enough space for this, so all we need to
+         * do here is to zero it out. */
+        a = ALIGN8(m->fields_size) - m->fields_size;
+        if (a > 0)
+                memzero((uint8_t*) BUS_MESSAGE_FIELDS(m) + m->fields_size, a);
+
+        /* If this is something we can send as memfd, then let's seal
+        the memfd now. Note that we can send memfds as payload only
+        for directed messages, and not for broadcasts. */
+        if (m->destination && m->bus->use_memfd) {
+                MESSAGE_FOREACH_PART(part, i, m)
+                        if (part->memfd >= 0 &&
+                            !part->sealed &&
+                            (part->size > MEMFD_MIN_SIZE || m->bus->use_memfd < 0) &&
+                            part != m->body_end) { /* The last part may never be sent as memfd */
+                                uint64_t sz;
+
+                                /* Try to seal it if that makes
+                                 * sense. First, unmap our own map to
+                                 * make sure we don't keep it busy. */
+                                bus_body_part_unmap(part);
+
+                                /* Then, sync up real memfd size */
+                                sz = part->size;
+                                r = memfd_set_size(part->memfd, sz);
+                                if (r < 0)
+                                        return r;
+
+                                /* Finally, try to seal */
+                                if (memfd_set_sealed(part->memfd) >= 0)
+                                        part->sealed = true;
+                        }
+        }
+
+        m->root_container.end = m->user_body_size;
+        m->root_container.index = 0;
+        m->root_container.offset_index = 0;
+        m->root_container.item_size = m->root_container.n_offsets > 0 ? m->root_container.offsets[0] : 0;
+
+        m->sealed = true;
+
+        return 0;
+}
+
+int bus_body_part_map(struct bus_body_part *part) {
+        void *p;
+        size_t psz, shift;
+
+        assert_se(part);
+
+        if (part->data)
+                return 0;
+
+        if (part->size <= 0)
+                return 0;
+
+        /* For smaller zero parts (as used for padding) we don't need to map anything... */
+        if (part->memfd < 0 && part->is_zero && part->size < 8) {
+                static const uint8_t zeroes[7] = { };
+                part->data = (void*) zeroes;
+                return 0;
+        }
+
+        shift = PAGE_OFFSET(part->memfd_offset);
+        psz = PAGE_ALIGN(part->size + shift);
+
+        if (part->memfd >= 0)
+                p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE, part->memfd, part->memfd_offset - shift);
+        else if (part->is_zero)
+                p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+        else
+                return -EINVAL;
+
+        if (p == MAP_FAILED)
+                return -errno;
+
+        part->mapped = psz;
+        part->mmap_begin = p;
+        part->data = (uint8_t*) p + shift;
+        part->munmap_this = true;
+
+        return 0;
+}
+
+void bus_body_part_unmap(struct bus_body_part *part) {
+
+        assert_se(part);
+
+        if (part->memfd < 0)
+                return;
+
+        if (!part->mmap_begin)
+                return;
+
+        if (!part->munmap_this)
+                return;
+
+        assert_se(munmap(part->mmap_begin, part->mapped) == 0);
+
+        part->mmap_begin = NULL;
+        part->data = NULL;
+        part->mapped = 0;
+        part->munmap_this = false;
+
+        return;
+}
+
+static int buffer_peek(const void *p, uint32_t sz, size_t *rindex, size_t align, size_t nbytes, void **r) {
+        size_t k, start, end;
+
+        assert(rindex);
+        assert(align > 0);
+
+        start = ALIGN_TO((size_t) *rindex, align);
+        end = start + nbytes;
+
+        if (end > sz)
+                return -EBADMSG;
+
+        /* Verify that padding is 0 */
+        for (k = *rindex; k < start; k++)
+                if (((const uint8_t*) p)[k] != 0)
+                        return -EBADMSG;
+
+        if (r)
+                *r = (uint8_t*) p + start;
+
+        *rindex = end;
+
+        return 1;
+}
+
+static bool message_end_of_signature(sd_bus_message *m) {
+        struct bus_container *c;
+
+        assert(m);
+
+        c = message_get_last_container(m);
+        return !c->signature || c->signature[c->index] == 0;
+}
+
+static bool message_end_of_array(sd_bus_message *m, size_t index) {
+        struct bus_container *c;
+
+        assert(m);
+
+        c = message_get_last_container(m);
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return false;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m))
+                return index >= c->end;
+        else {
+                assert(c->array_size);
+                return index >= c->begin + BUS_MESSAGE_BSWAP32(m, *c->array_size);
+        }
+}
+
+_public_ int sd_bus_message_at_end(sd_bus_message *m, int complete) {
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        if (complete && m->n_containers > 0)
+                return false;
+
+        if (message_end_of_signature(m))
+                return true;
+
+        if (message_end_of_array(m, m->rindex))
+                return true;
+
+        return false;
+}
+
+static struct bus_body_part* find_part(sd_bus_message *m, size_t index, size_t sz, void **p) {
+        struct bus_body_part *part;
+        size_t begin;
+        int r;
+
+        assert(m);
+
+        if (m->cached_rindex_part && index >= m->cached_rindex_part_begin) {
+                part = m->cached_rindex_part;
+                begin = m->cached_rindex_part_begin;
+        } else {
+                part = &m->body;
+                begin = 0;
+        }
+
+        while (part) {
+                if (index < begin)
+                        return NULL;
+
+                if (index + sz <= begin + part->size) {
+
+                        r = bus_body_part_map(part);
+                        if (r < 0)
+                                return NULL;
+
+                        if (p)
+                                *p = part->data ? (uint8_t*) part->data + index - begin
+                                        : NULL; /* Avoid dereferencing a NULL pointer. */
+
+                        m->cached_rindex_part = part;
+                        m->cached_rindex_part_begin = begin;
+
+                        return part;
+                }
+
+                begin += part->size;
+                part = part->next;
+        }
+
+        return NULL;
+}
+
+static int container_next_item(sd_bus_message *m, struct bus_container *c, size_t *rindex) {
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(rindex);
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m))
+                return 0;
+
+        if (c->enclosing == SD_BUS_TYPE_ARRAY) {
+                int sz;
+
+                sz = bus_gvariant_get_size(c->signature);
+                if (sz == 0)
+                        return -EBADMSG;
+                if (sz < 0) {
+                        int alignment;
+
+                        if (c->offset_index+1 >= c->n_offsets)
+                                goto end;
+
+                        /* Variable-size array */
+
+                        alignment = bus_gvariant_get_alignment(c->signature);
+                        assert(alignment > 0);
+
+                        *rindex = ALIGN_TO(c->offsets[c->offset_index], alignment);
+                        assert(c->offsets[c->offset_index+1] >= *rindex);
+                        c->item_size = c->offsets[c->offset_index+1] - *rindex;
+                } else {
+
+                        if (c->offset_index+1 >= (c->end-c->begin)/sz)
+                                goto end;
+
+                        /* Fixed-size array */
+                        *rindex = c->begin + (c->offset_index+1) * sz;
+                        c->item_size = sz;
+                }
+
+                c->offset_index++;
+
+        } else if (IN_SET(c->enclosing, 0, SD_BUS_TYPE_STRUCT, SD_BUS_TYPE_DICT_ENTRY)) {
+
+                int alignment;
+                size_t n, j;
+
+                if (c->offset_index+1 >= c->n_offsets)
+                        goto end;
+
+                r = signature_element_length(c->signature + c->index, &n);
+                if (r < 0)
+                        return r;
+
+                r = signature_element_length(c->signature + c->index + n, &j);
+                if (r < 0)
+                        return r;
+                else {
+                        char t[j+1];
+                        memcpy(t, c->signature + c->index + n, j);
+                        t[j] = 0;
+
+                        alignment = bus_gvariant_get_alignment(t);
+                }
+
+                assert(alignment > 0);
+
+                *rindex = ALIGN_TO(c->offsets[c->offset_index], alignment);
+                assert(c->offsets[c->offset_index+1] >= *rindex);
+                c->item_size = c->offsets[c->offset_index+1] - *rindex;
+
+                c->offset_index++;
+
+        } else if (c->enclosing == SD_BUS_TYPE_VARIANT)
+                goto end;
+        else
+                assert_not_reached("Unknown container type");
+
+        return 0;
+
+end:
+        /* Reached the end */
+        *rindex = c->end;
+        c->item_size = 0;
+        return 0;
+}
+
+static int message_peek_body(
+                sd_bus_message *m,
+                size_t *rindex,
+                size_t align,
+                size_t nbytes,
+                void **ret) {
+
+        size_t k, start, end, padding;
+        struct bus_body_part *part;
+        uint8_t *q;
+
+        assert(m);
+        assert(rindex);
+        assert(align > 0);
+
+        start = ALIGN_TO((size_t) *rindex, align);
+        padding = start - *rindex;
+        end = start + nbytes;
+
+        if (end > m->user_body_size)
+                return -EBADMSG;
+
+        part = find_part(m, *rindex, padding, (void**) &q);
+        if (!part)
+                return -EBADMSG;
+
+        if (q) {
+                /* Verify padding */
+                for (k = 0; k < padding; k++)
+                        if (q[k] != 0)
+                                return -EBADMSG;
+        }
+
+        part = find_part(m, start, nbytes, (void**) &q);
+        if (!part || (nbytes > 0 && !q))
+                return -EBADMSG;
+
+        *rindex = end;
+
+        if (ret)
+                *ret = q;
+
+        return 0;
+}
+
+static bool validate_nul(const char *s, size_t l) {
+
+        /* Check for NUL chars in the string */
+        if (memchr(s, 0, l))
+                return false;
+
+        /* Check for NUL termination */
+        if (s[l] != 0)
+                return false;
+
+        return true;
+}
+
+static bool validate_string(const char *s, size_t l) {
+
+        if (!validate_nul(s, l))
+                return false;
+
+        /* Check if valid UTF8 */
+        if (!utf8_is_valid(s))
+                return false;
+
+        return true;
+}
+
+static bool validate_signature(const char *s, size_t l) {
+
+        if (!validate_nul(s, l))
+                return false;
+
+        /* Check if valid signature */
+        if (!signature_is_valid(s, true))
+                return false;
+
+        return true;
+}
+
+static bool validate_object_path(const char *s, size_t l) {
+
+        if (!validate_nul(s, l))
+                return false;
+
+        if (!object_path_is_valid(s))
+                return false;
+
+        return true;
+}
+
+_public_ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
+        struct bus_container *c;
+        size_t rindex;
+        void *q;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(bus_type_is_basic(type), -EINVAL);
+
+        if (message_end_of_signature(m))
+                return -ENXIO;
+
+        if (message_end_of_array(m, m->rindex))
+                return 0;
+
+        c = message_get_last_container(m);
+        if (c->signature[c->index] != type)
+                return -ENXIO;
+
+        rindex = m->rindex;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+
+                if (IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE)) {
+                        bool ok;
+
+                        /* D-Bus spec: The marshalling formats for the string-like types all end
+                         * with a single zero (NUL) byte, but that byte is not considered to be part
+                         * of the text. */
+                        if (c->item_size == 0)
+                                return -EBADMSG;
+
+                        r = message_peek_body(m, &rindex, 1, c->item_size, &q);
+                        if (r < 0)
+                                return r;
+
+                        if (type == SD_BUS_TYPE_STRING)
+                                ok = validate_string(q, c->item_size-1);
+                        else if (type == SD_BUS_TYPE_OBJECT_PATH)
+                                ok = validate_object_path(q, c->item_size-1);
+                        else
+                                ok = validate_signature(q, c->item_size-1);
+
+                        if (!ok)
+                                return -EBADMSG;
+
+                        if (p)
+                                *(const char**) p = q;
+                } else {
+                        int sz, align;
+
+                        sz = bus_gvariant_get_size(CHAR_TO_STR(type));
+                        assert(sz > 0);
+                        if ((size_t) sz != c->item_size)
+                                return -EBADMSG;
+
+                        align = bus_gvariant_get_alignment(CHAR_TO_STR(type));
+                        assert(align > 0);
+
+                        r = message_peek_body(m, &rindex, align, c->item_size, &q);
+                        if (r < 0)
+                                return r;
+
+                        switch (type) {
+
+                        case SD_BUS_TYPE_BYTE:
+                                if (p)
+                                        *(uint8_t*) p = *(uint8_t*) q;
+                                break;
+
+                        case SD_BUS_TYPE_BOOLEAN:
+                                if (p)
+                                        *(int*) p = !!*(uint8_t*) q;
+                                break;
+
+                        case SD_BUS_TYPE_INT16:
+                        case SD_BUS_TYPE_UINT16:
+                                if (p)
+                                        *(uint16_t*) p = BUS_MESSAGE_BSWAP16(m, *(uint16_t*) q);
+                                break;
+
+                        case SD_BUS_TYPE_INT32:
+                        case SD_BUS_TYPE_UINT32:
+                                if (p)
+                                        *(uint32_t*) p = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                                break;
+
+                        case SD_BUS_TYPE_INT64:
+                        case SD_BUS_TYPE_UINT64:
+                        case SD_BUS_TYPE_DOUBLE:
+                                if (p)
+                                        *(uint64_t*) p = BUS_MESSAGE_BSWAP64(m, *(uint64_t*) q);
+                                break;
+
+                        case SD_BUS_TYPE_UNIX_FD: {
+                                uint32_t j;
+
+                                j = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                                if (j >= m->n_fds)
+                                        return -EBADMSG;
+
+                                if (p)
+                                        *(int*) p = m->fds[j];
+
+                                break;
+                        }
+
+                        default:
+                                assert_not_reached("unexpected type");
+                        }
+                }
+
+                r = container_next_item(m, c, &rindex);
+                if (r < 0)
+                        return r;
+        } else {
+
+                if (IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH)) {
+                        uint32_t l;
+                        bool ok;
+
+                        r = message_peek_body(m, &rindex, 4, 4, &q);
+                        if (r < 0)
+                                return r;
+
+                        l = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                        if (l == UINT32_MAX)
+                                /* avoid overflow right below */
+                                return -EBADMSG;
+
+                        r = message_peek_body(m, &rindex, 1, l+1, &q);
+                        if (r < 0)
+                                return r;
+
+                        if (type == SD_BUS_TYPE_OBJECT_PATH)
+                                ok = validate_object_path(q, l);
+                        else
+                                ok = validate_string(q, l);
+                        if (!ok)
+                                return -EBADMSG;
+
+                        if (p)
+                                *(const char**) p = q;
+
+                } else if (type == SD_BUS_TYPE_SIGNATURE) {
+                        uint8_t l;
+
+                        r = message_peek_body(m, &rindex, 1, 1, &q);
+                        if (r < 0)
+                                return r;
+
+                        l = *(uint8_t*) q;
+                        if (l == UINT8_MAX)
+                                /* avoid overflow right below */
+                                return -EBADMSG;
+
+                        r = message_peek_body(m, &rindex, 1, l+1, &q);
+                        if (r < 0)
+                                return r;
+
+                        if (!validate_signature(q, l))
+                                return -EBADMSG;
+
+                        if (p)
+                                *(const char**) p = q;
+
+                } else {
+                        ssize_t sz, align;
+
+                        align = bus_type_get_alignment(type);
+                        assert(align > 0);
+
+                        sz = bus_type_get_size(type);
+                        assert(sz > 0);
+
+                        r = message_peek_body(m, &rindex, align, sz, &q);
+                        if (r < 0)
+                                return r;
+
+                        switch (type) {
+
+                        case SD_BUS_TYPE_BYTE:
+                                if (p)
+                                        *(uint8_t*) p = *(uint8_t*) q;
+                                break;
+
+                        case SD_BUS_TYPE_BOOLEAN:
+                                if (p)
+                                        *(int*) p = !!*(uint32_t*) q;
+                                break;
+
+                        case SD_BUS_TYPE_INT16:
+                        case SD_BUS_TYPE_UINT16:
+                                if (p)
+                                        *(uint16_t*) p = BUS_MESSAGE_BSWAP16(m, *(uint16_t*) q);
+                                break;
+
+                        case SD_BUS_TYPE_INT32:
+                        case SD_BUS_TYPE_UINT32:
+                                if (p)
+                                        *(uint32_t*) p = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                                break;
+
+                        case SD_BUS_TYPE_INT64:
+                        case SD_BUS_TYPE_UINT64:
+                        case SD_BUS_TYPE_DOUBLE:
+                                if (p)
+                                        *(uint64_t*) p = BUS_MESSAGE_BSWAP64(m, *(uint64_t*) q);
+                                break;
+
+                        case SD_BUS_TYPE_UNIX_FD: {
+                                uint32_t j;
+
+                                j = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                                if (j >= m->n_fds)
+                                        return -EBADMSG;
+
+                                if (p)
+                                        *(int*) p = m->fds[j];
+                                break;
+                        }
+
+                        default:
+                                assert_not_reached("Unknown basic type...");
+                        }
+                }
+        }
+
+        m->rindex = rindex;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 1;
+}
+
+static int bus_message_enter_array(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                uint32_t **array_size,
+                size_t *item_size,
+                size_t **offsets,
+                size_t *n_offsets) {
+
+        size_t rindex;
+        void *q;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(array_size);
+        assert(item_size);
+        assert(offsets);
+        assert(n_offsets);
+
+        if (!signature_is_single(contents, true))
+                return -EINVAL;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return -ENXIO;
+
+        if (c->signature[c->index] != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+
+        if (!startswith(c->signature + c->index + 1, contents))
+                return -ENXIO;
+
+        rindex = m->rindex;
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m)) {
+                /* dbus1 */
+                int alignment;
+
+                r = message_peek_body(m, &rindex, 4, 4, &q);
+                if (r < 0)
+                        return r;
+
+                if (BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q) > BUS_ARRAY_MAX_SIZE)
+                        return -EBADMSG;
+
+                alignment = bus_type_get_alignment(contents[0]);
+                if (alignment < 0)
+                        return alignment;
+
+                r = message_peek_body(m, &rindex, alignment, 0, NULL);
+                if (r < 0)
+                        return r;
+
+                *array_size = (uint32_t*) q;
+
+        } else if (c->item_size <= 0) {
+
+                /* gvariant: empty array */
+                *item_size = 0;
+                *offsets = NULL;
+                *n_offsets = 0;
+
+        } else if (bus_gvariant_is_fixed_size(contents)) {
+
+                /* gvariant: fixed length array */
+                *item_size = bus_gvariant_get_size(contents);
+                *offsets = NULL;
+                *n_offsets = 0;
+
+        } else {
+                size_t where, previous = 0, framing, sz;
+                int alignment;
+                unsigned i;
+
+                /* gvariant: variable length array */
+                sz = bus_gvariant_determine_word_size(c->item_size, 0);
+
+                where = rindex + c->item_size - sz;
+                r = message_peek_body(m, &where, 1, sz, &q);
+                if (r < 0)
+                        return r;
+
+                framing = bus_gvariant_read_word_le(q, sz);
+                if (framing > c->item_size - sz)
+                        return -EBADMSG;
+                if ((c->item_size - framing) % sz != 0)
+                        return -EBADMSG;
+
+                *n_offsets = (c->item_size - framing) / sz;
+
+                where = rindex + framing;
+                r = message_peek_body(m, &where, 1, *n_offsets * sz, &q);
+                if (r < 0)
+                        return r;
+
+                *offsets = new(size_t, *n_offsets);
+                if (!*offsets)
+                        return -ENOMEM;
+
+                alignment = bus_gvariant_get_alignment(c->signature);
+                assert(alignment > 0);
+
+                for (i = 0; i < *n_offsets; i++) {
+                        size_t x, start;
+
+                        start = ALIGN_TO(previous, alignment);
+
+                        x = bus_gvariant_read_word_le((uint8_t*) q + i * sz, sz);
+                        if (x > c->item_size - sz)
+                                return -EBADMSG;
+                        if (x < start)
+                                return -EBADMSG;
+
+                        (*offsets)[i] = rindex + x;
+                        previous = x;
+                }
+
+                *item_size = (*offsets)[0] - rindex;
+        }
+
+        m->rindex = rindex;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index += 1 + strlen(contents);
+
+        return 1;
+}
+
+static int bus_message_enter_variant(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *item_size) {
+
+        size_t rindex;
+        uint8_t l;
+        void *q;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(item_size);
+
+        if (!signature_is_single(contents, false))
+                return -EINVAL;
+
+        if (*contents == SD_BUS_TYPE_DICT_ENTRY_BEGIN)
+                return -EINVAL;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return -ENXIO;
+
+        if (c->signature[c->index] != SD_BUS_TYPE_VARIANT)
+                return -ENXIO;
+
+        rindex = m->rindex;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                size_t k, where;
+
+                k = strlen(contents);
+                if (1+k > c->item_size)
+                        return -EBADMSG;
+
+                where = rindex + c->item_size - (1+k);
+                r = message_peek_body(m, &where, 1, 1+k, &q);
+                if (r < 0)
+                        return r;
+
+                if (*(char*) q != 0)
+                        return -EBADMSG;
+
+                if (memcmp((uint8_t*) q+1, contents, k))
+                        return -ENXIO;
+
+                *item_size = c->item_size - (1+k);
+
+        } else {
+                r = message_peek_body(m, &rindex, 1, 1, &q);
+                if (r < 0)
+                        return r;
+
+                l = *(uint8_t*) q;
+                if (l == UINT8_MAX)
+                        /* avoid overflow right below */
+                        return -EBADMSG;
+
+                r = message_peek_body(m, &rindex, 1, l+1, &q);
+                if (r < 0)
+                        return r;
+
+                if (!validate_signature(q, l))
+                        return -EBADMSG;
+
+                if (!streq(q, contents))
+                        return -ENXIO;
+        }
+
+        m->rindex = rindex;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index++;
+
+        return 1;
+}
+
+static int build_struct_offsets(
+                sd_bus_message *m,
+                const char *signature,
+                size_t size,
+                size_t *item_size,
+                size_t **offsets,
+                size_t *n_offsets) {
+
+        unsigned n_variable = 0, n_total = 0, v;
+        size_t previous, where;
+        const char *p;
+        size_t sz;
+        void *q;
+        int r;
+
+        assert(m);
+        assert(item_size);
+        assert(offsets);
+        assert(n_offsets);
+
+        if (isempty(signature)) {
+                /* Unary type is encoded as *fixed* 1 byte padding */
+                r = message_peek_body(m, &m->rindex, 1, 1, &q);
+                if (r < 0)
+                        return r;
+
+                if (*(uint8_t *) q != 0)
+                        return -EBADMSG;
+
+                *item_size = 0;
+                *offsets = NULL;
+                *n_offsets = 0;
+                return 0;
+        }
+
+        sz = bus_gvariant_determine_word_size(size, 0);
+        if (sz <= 0)
+                return -EBADMSG;
+
+        /* First, loop over signature and count variable elements and
+         * elements in general. We use this to know how large the
+         * offset array is at the end of the structure. Note that
+         * GVariant only stores offsets for all variable size elements
+         * that are not the last item. */
+
+        p = signature;
+        while (*p != 0) {
+                size_t n;
+
+                r = signature_element_length(p, &n);
+                if (r < 0)
+                        return r;
+                else {
+                        char t[n+1];
+
+                        memcpy(t, p, n);
+                        t[n] = 0;
+
+                        r = bus_gvariant_is_fixed_size(t);
+                }
+
+                if (r < 0)
+                        return r;
+                if (r == 0 && p[n] != 0) /* except the last item */
+                        n_variable++;
+                n_total++;
+
+                p += n;
+        }
+
+        if (size < n_variable * sz)
+                return -EBADMSG;
+
+        where = m->rindex + size - (n_variable * sz);
+        r = message_peek_body(m, &where, 1, n_variable * sz, &q);
+        if (r < 0)
+                return r;
+
+        v = n_variable;
+
+        *offsets = new(size_t, n_total);
+        if (!*offsets)
+                return -ENOMEM;
+
+        *n_offsets = 0;
+
+        /* Second, loop again and build an offset table */
+        p = signature;
+        previous = m->rindex;
+        while (*p != 0) {
+                size_t n, offset;
+                int k;
+
+                r = signature_element_length(p, &n);
+                if (r < 0)
+                        return r;
+                else {
+                        char t[n+1];
+
+                        memcpy(t, p, n);
+                        t[n] = 0;
+
+                        size_t align = bus_gvariant_get_alignment(t);
+                        assert(align > 0);
+
+                        /* The possible start of this member after including alignment */
+                        size_t start = ALIGN_TO(previous, align);
+
+                        k = bus_gvariant_get_size(t);
+                        if (k < 0) {
+                                size_t x;
+
+                                /* Variable size */
+                                if (v > 0) {
+                                        v--;
+
+                                        x = bus_gvariant_read_word_le((uint8_t*) q + v*sz, sz);
+                                        if (x >= size)
+                                                return -EBADMSG;
+                                } else
+                                        /* The last item's end is determined
+                                         * from the start of the offset array */
+                                        x = size - (n_variable * sz);
+
+                                offset = m->rindex + x;
+                                if (offset < start)
+                                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                                               "For type %s with alignment %zu, message specifies offset %zu which is smaller than previous end %zu + alignment = %zu",
+                                                               t, align,
+                                                               offset,
+                                                               previous,
+                                                               start);
+                        } else
+                                /* Fixed size */
+                                offset = start + k;
+                }
+
+                previous = (*offsets)[(*n_offsets)++] = offset;
+                p += n;
+        }
+
+        assert(v == 0);
+        assert(*n_offsets == n_total);
+
+        *item_size = (*offsets)[0] - m->rindex;
+        return 0;
+}
+
+static int enter_struct_or_dict_entry(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *item_size,
+                size_t **offsets,
+                size_t *n_offsets) {
+
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(item_size);
+        assert(offsets);
+        assert(n_offsets);
+
+        if (!BUS_MESSAGE_IS_GVARIANT(m)) {
+
+                /* dbus1 */
+                r = message_peek_body(m, &m->rindex, 8, 0, NULL);
+                if (r < 0)
+                        return r;
+
+        } else
+                /* gvariant with contents */
+                return build_struct_offsets(m, contents, c->item_size, item_size, offsets, n_offsets);
+
+        return 0;
+}
+
+static int bus_message_enter_struct(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *item_size,
+                size_t **offsets,
+                size_t *n_offsets) {
+
+        size_t l;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+        assert(item_size);
+        assert(offsets);
+        assert(n_offsets);
+
+        if (!signature_is_valid(contents, false))
+                return -EINVAL;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return -ENXIO;
+
+        l = strlen(contents);
+
+        if (c->signature[c->index] != SD_BUS_TYPE_STRUCT_BEGIN ||
+            !startswith(c->signature + c->index + 1, contents) ||
+            c->signature[c->index + 1 + l] != SD_BUS_TYPE_STRUCT_END)
+                return -ENXIO;
+
+        r = enter_struct_or_dict_entry(m, c, contents, item_size, offsets, n_offsets);
+        if (r < 0)
+                return r;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index += 1 + l + 1;
+
+        return 1;
+}
+
+static int bus_message_enter_dict_entry(
+                sd_bus_message *m,
+                struct bus_container *c,
+                const char *contents,
+                size_t *item_size,
+                size_t **offsets,
+                size_t *n_offsets) {
+
+        size_t l;
+        int r;
+
+        assert(m);
+        assert(c);
+        assert(contents);
+
+        if (!signature_is_pair(contents))
+                return -EINVAL;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+
+        if (!c->signature || c->signature[c->index] == 0)
+                return 0;
+
+        l = strlen(contents);
+
+        if (c->signature[c->index] != SD_BUS_TYPE_DICT_ENTRY_BEGIN ||
+            !startswith(c->signature + c->index + 1, contents) ||
+            c->signature[c->index + 1 + l] != SD_BUS_TYPE_DICT_ENTRY_END)
+                return -ENXIO;
+
+        r = enter_struct_or_dict_entry(m, c, contents, item_size, offsets, n_offsets);
+        if (r < 0)
+                return r;
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY)
+                c->index += 1 + l + 1;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_enter_container(sd_bus_message *m,
+                                            char type,
+                                            const char *contents) {
+        struct bus_container *c;
+        uint32_t *array_size = NULL;
+        _cleanup_free_ char *signature = NULL;
+        size_t before, end;
+        _cleanup_free_ size_t *offsets = NULL;
+        size_t n_offsets = 0, item_size = 0;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(type != 0 || !contents, -EINVAL);
+
+        if (type == 0 || !contents) {
+                const char *cc;
+                char tt;
+
+                /* Allow entering into anonymous containers */
+                r = sd_bus_message_peek_type(m, &tt, &cc);
+                if (r < 0)
+                        return r;
+
+                if (type != 0 && type != tt)
+                        return -ENXIO;
+
+                if (contents && !streq(contents, cc))
+                        return -ENXIO;
+
+                type = tt;
+                contents = cc;
+        }
+
+        /*
+         * We enforce a global limit on container depth, that is much
+         * higher than the 32 structs and 32 arrays the specification
+         * mandates. This is simpler to implement for us, and we need
+         * this only to ensure our container array doesn't grow
+         * without bounds. We are happy to return any data from a
+         * message as long as the data itself is valid, even if the
+         * overall message might be not.
+         *
+         * Note that the message signature is validated when
+         * parsing the headers, and that validation does check the
+         * 32/32 limit.
+         *
+         * Note that the specification defines no limits on the depth
+         * of stacked variants, but we do.
+         */
+        if (m->n_containers >= BUS_CONTAINER_DEPTH)
+                return -EBADMSG;
+
+        if (!GREEDY_REALLOC(m->containers, m->containers_allocated, m->n_containers + 1))
+                return -ENOMEM;
+
+        if (message_end_of_signature(m))
+                return -ENXIO;
+
+        if (message_end_of_array(m, m->rindex))
+                return 0;
+
+        c = message_get_last_container(m);
+
+        signature = strdup(contents);
+        if (!signature)
+                return -ENOMEM;
+
+        c->saved_index = c->index;
+        before = m->rindex;
+
+        if (type == SD_BUS_TYPE_ARRAY)
+                r = bus_message_enter_array(m, c, contents, &array_size, &item_size, &offsets, &n_offsets);
+        else if (type == SD_BUS_TYPE_VARIANT)
+                r = bus_message_enter_variant(m, c, contents, &item_size);
+        else if (type == SD_BUS_TYPE_STRUCT)
+                r = bus_message_enter_struct(m, c, contents, &item_size, &offsets, &n_offsets);
+        else if (type == SD_BUS_TYPE_DICT_ENTRY)
+                r = bus_message_enter_dict_entry(m, c, contents, &item_size, &offsets, &n_offsets);
+        else
+                r = -EINVAL;
+        if (r <= 0)
+                return r;
+
+        /* OK, let's fill it in */
+        if (BUS_MESSAGE_IS_GVARIANT(m) &&
+            type == SD_BUS_TYPE_STRUCT &&
+            isempty(signature))
+                end = m->rindex + 0;
+        else
+                end = m->rindex + c->item_size;
+
+        m->containers[m->n_containers++] = (struct bus_container) {
+                 .enclosing = type,
+                 .signature = TAKE_PTR(signature),
+
+                 .before = before,
+                 .begin = m->rindex,
+                 /* Unary type has fixed size of 1, but virtual size of 0 */
+                 .end = end,
+                 .array_size = array_size,
+                 .item_size = item_size,
+                 .offsets = TAKE_PTR(offsets),
+                 .n_offsets = n_offsets,
+        };
+
+        return 1;
+}
+
+_public_ int sd_bus_message_exit_container(sd_bus_message *m) {
+        struct bus_container *c;
+        unsigned saved;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(m->n_containers > 0, -ENXIO);
+
+        c = message_get_last_container(m);
+
+        if (c->enclosing != SD_BUS_TYPE_ARRAY) {
+                if (c->signature && c->signature[c->index] != 0)
+                        return -EBUSY;
+        }
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                if (m->rindex < c->end)
+                        return -EBUSY;
+
+        } else if (c->enclosing == SD_BUS_TYPE_ARRAY) {
+                uint32_t l;
+
+                l = BUS_MESSAGE_BSWAP32(m, *c->array_size);
+                if (c->begin + l != m->rindex)
+                        return -EBUSY;
+        }
+
+        message_free_last_container(m);
+
+        c = message_get_last_container(m);
+        saved = c->index;
+        c->index = c->saved_index;
+        r = container_next_item(m, c, &m->rindex);
+        c->index = saved;
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static void message_quit_container(sd_bus_message *m) {
+        struct bus_container *c;
+
+        assert(m);
+        assert(m->sealed);
+        assert(m->n_containers > 0);
+
+        /* Undo seeks */
+        c = message_get_last_container(m);
+        assert(m->rindex >= c->before);
+        m->rindex = c->before;
+
+        /* Free container */
+        message_free_last_container(m);
+
+        /* Correct index of new top-level container */
+        c = message_get_last_container(m);
+        c->index = c->saved_index;
+}
+
+_public_ int sd_bus_message_peek_type(sd_bus_message *m, char *type, const char **contents) {
+        struct bus_container *c;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        if (message_end_of_signature(m))
+                goto eof;
+
+        if (message_end_of_array(m, m->rindex))
+                goto eof;
+
+        c = message_get_last_container(m);
+
+        if (bus_type_is_basic(c->signature[c->index])) {
+                if (contents)
+                        *contents = NULL;
+                if (type)
+                        *type = c->signature[c->index];
+                return 1;
+        }
+
+        if (c->signature[c->index] == SD_BUS_TYPE_ARRAY) {
+
+                if (contents) {
+                        size_t l;
+
+                        r = signature_element_length(c->signature+c->index+1, &l);
+                        if (r < 0)
+                                return r;
+
+                        /* signature_element_length does verification internally */
+
+                        /* The array element must not be empty */
+                        assert(l >= 1);
+                        if (free_and_strndup(&c->peeked_signature,
+                                             c->signature + c->index + 1, l) < 0)
+                                return -ENOMEM;
+
+                        *contents = c->peeked_signature;
+                }
+
+                if (type)
+                        *type = SD_BUS_TYPE_ARRAY;
+
+                return 1;
+        }
+
+        if (IN_SET(c->signature[c->index], SD_BUS_TYPE_STRUCT_BEGIN, SD_BUS_TYPE_DICT_ENTRY_BEGIN)) {
+
+                if (contents) {
+                        size_t l;
+
+                        r = signature_element_length(c->signature+c->index, &l);
+                        if (r < 0)
+                                return r;
+
+                        assert(l >= 3);
+                        if (free_and_strndup(&c->peeked_signature,
+                                             c->signature + c->index + 1, l - 2) < 0)
+                                return -ENOMEM;
+
+                        *contents = c->peeked_signature;
+                }
+
+                if (type)
+                        *type = c->signature[c->index] == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY;
+
+                return 1;
+        }
+
+        if (c->signature[c->index] == SD_BUS_TYPE_VARIANT) {
+                if (contents) {
+                        void *q;
+
+                        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                                size_t k;
+
+                                if (c->item_size < 2)
+                                        return -EBADMSG;
+
+                                /* Look for the NUL delimiter that
+                                   separates the payload from the
+                                   signature. Since the body might be
+                                   in a different part that then the
+                                   signature we map byte by byte. */
+
+                                for (k = 2; k <= c->item_size; k++) {
+                                        size_t where;
+
+                                        where = m->rindex + c->item_size - k;
+                                        r = message_peek_body(m, &where, 1, k, &q);
+                                        if (r < 0)
+                                                return r;
+
+                                        if (*(char*) q == 0)
+                                                break;
+                                }
+
+                                if (k > c->item_size)
+                                        return -EBADMSG;
+
+                                if (free_and_strndup(&c->peeked_signature,
+                                                     (char*) q + 1, k - 1) < 0)
+                                        return -ENOMEM;
+
+                                if (!signature_is_valid(c->peeked_signature, true))
+                                        return -EBADMSG;
+
+                                *contents = c->peeked_signature;
+                        } else {
+                                size_t rindex, l;
+
+                                rindex = m->rindex;
+                                r = message_peek_body(m, &rindex, 1, 1, &q);
+                                if (r < 0)
+                                        return r;
+
+                                l = *(uint8_t*) q;
+                                if (l == UINT8_MAX)
+                                        /* avoid overflow right below */
+                                        return -EBADMSG;
+
+                                r = message_peek_body(m, &rindex, 1, l+1, &q);
+                                if (r < 0)
+                                        return r;
+
+                                if (!validate_signature(q, l))
+                                        return -EBADMSG;
+
+                                *contents = q;
+                        }
+                }
+
+                if (type)
+                        *type = SD_BUS_TYPE_VARIANT;
+
+                return 1;
+        }
+
+        return -EINVAL;
+
+eof:
+        if (type)
+                *type = 0;
+        if (contents)
+                *contents = NULL;
+        return 0;
+}
+
+_public_ int sd_bus_message_rewind(sd_bus_message *m, int complete) {
+        struct bus_container *c;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        if (complete) {
+                message_reset_containers(m);
+                m->rindex = 0;
+
+                c = message_get_last_container(m);
+        } else {
+                c = message_get_last_container(m);
+
+                c->index = 0;
+                m->rindex = c->begin;
+        }
+
+        c->offset_index = 0;
+        c->item_size = (c->n_offsets > 0 ? c->offsets[0] : c->end) - c->begin;
+
+        return !isempty(c->signature);
+}
+
+_public_ int sd_bus_message_readv(
+                sd_bus_message *m,
+                const char *types,
+                va_list ap) {
+
+        unsigned n_array, n_struct;
+        TypeStack stack[BUS_CONTAINER_DEPTH];
+        unsigned stack_ptr = 0;
+        unsigned n_loop = 0;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(types, -EINVAL);
+
+        if (isempty(types))
+                return 0;
+
+        /* Ideally, we'd just call ourselves recursively on every
+         * complex type. However, the state of a va_list that is
+         * passed to a function is undefined after that function
+         * returns. This means we need to decode the va_list linearly
+         * in a single stackframe. We hence implement our own
+         * home-grown stack in an array. */
+
+        n_array = (unsigned) -1; /* length of current array entries */
+        n_struct = strlen(types); /* length of current struct contents signature */
+
+        for (;;) {
+                const char *t;
+
+                n_loop++;
+
+                if (n_array == 0 || (n_array == (unsigned) -1 && n_struct == 0)) {
+                        r = type_stack_pop(stack, ELEMENTSOF(stack), &stack_ptr, &types, &n_struct, &n_array);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                t = types;
+                if (n_array != (unsigned) -1)
+                        n_array--;
+                else {
+                        types++;
+                        n_struct--;
+                }
+
+                switch (*t) {
+
+                case SD_BUS_TYPE_BYTE:
+                case SD_BUS_TYPE_BOOLEAN:
+                case SD_BUS_TYPE_INT16:
+                case SD_BUS_TYPE_UINT16:
+                case SD_BUS_TYPE_INT32:
+                case SD_BUS_TYPE_UINT32:
+                case SD_BUS_TYPE_INT64:
+                case SD_BUS_TYPE_UINT64:
+                case SD_BUS_TYPE_DOUBLE:
+                case SD_BUS_TYPE_STRING:
+                case SD_BUS_TYPE_OBJECT_PATH:
+                case SD_BUS_TYPE_SIGNATURE:
+                case SD_BUS_TYPE_UNIX_FD: {
+                        void *p;
+
+                        p = va_arg(ap, void*);
+                        r = sd_bus_message_read_basic(m, *t, p);
+                        if (r < 0)
+                                return r;
+                        if (r == 0) {
+                                if (n_loop <= 1)
+                                        return 0;
+
+                                return -ENXIO;
+                        }
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_ARRAY: {
+                        size_t k;
+
+                        r = signature_element_length(t + 1, &k);
+                        if (r < 0)
+                                return r;
+
+                        {
+                                char s[k + 1];
+                                memcpy(s, t + 1, k);
+                                s[k] = 0;
+
+                                r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, s);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0) {
+                                        if (n_loop <= 1)
+                                                return 0;
+
+                                        return -ENXIO;
+                                }
+                        }
+
+                        if (n_array == (unsigned) -1) {
+                                types += k;
+                                n_struct -= k;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k;
+                        n_array = va_arg(ap, unsigned);
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_VARIANT: {
+                        const char *s;
+
+                        s = va_arg(ap, const char *);
+                        if (!s)
+                                return -EINVAL;
+
+                        r = sd_bus_message_enter_container(m, SD_BUS_TYPE_VARIANT, s);
+                        if (r < 0)
+                                return r;
+                        if (r == 0) {
+                                if (n_loop <= 1)
+                                        return 0;
+
+                                return -ENXIO;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = s;
+                        n_struct = strlen(s);
+                        n_array = (unsigned) -1;
+
+                        break;
+                }
+
+                case SD_BUS_TYPE_STRUCT_BEGIN:
+                case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                        size_t k;
+
+                        r = signature_element_length(t, &k);
+                        if (r < 0)
+                                return r;
+
+                        {
+                                char s[k - 1];
+                                memcpy(s, t + 1, k - 2);
+                                s[k - 2] = 0;
+
+                                r = sd_bus_message_enter_container(m, *t == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY, s);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0) {
+                                        if (n_loop <= 1)
+                                                return 0;
+                                        return -ENXIO;
+                                }
+                        }
+
+                        if (n_array == (unsigned) -1) {
+                                types += k - 1;
+                                n_struct -= k - 1;
+                        }
+
+                        r = type_stack_push(stack, ELEMENTSOF(stack), &stack_ptr, types, n_struct, n_array);
+                        if (r < 0)
+                                return r;
+
+                        types = t + 1;
+                        n_struct = k - 2;
+                        n_array = (unsigned) -1;
+
+                        break;
+                }
+
+                default:
+                        return -EINVAL;
+                }
+        }
+
+        return 1;
+}
+
+_public_ int sd_bus_message_read(sd_bus_message *m, const char *types, ...) {
+        va_list ap;
+        int r;
+
+        va_start(ap, types);
+        r = sd_bus_message_readv(m, types, ap);
+        va_end(ap);
+
+        return r;
+}
+
+_public_ int sd_bus_message_skip(sd_bus_message *m, const char *types) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+
+        /* If types is NULL, read exactly one element */
+        if (!types) {
+                struct bus_container *c;
+                size_t l;
+
+                if (message_end_of_signature(m))
+                        return -ENXIO;
+
+                if (message_end_of_array(m, m->rindex))
+                        return 0;
+
+                c = message_get_last_container(m);
+
+                r = signature_element_length(c->signature + c->index, &l);
+                if (r < 0)
+                        return r;
+
+                types = strndupa(c->signature + c->index, l);
+        }
+
+        switch (*types) {
+
+        case 0: /* Nothing to drop */
+                return 0;
+
+        case SD_BUS_TYPE_BYTE:
+        case SD_BUS_TYPE_BOOLEAN:
+        case SD_BUS_TYPE_INT16:
+        case SD_BUS_TYPE_UINT16:
+        case SD_BUS_TYPE_INT32:
+        case SD_BUS_TYPE_UINT32:
+        case SD_BUS_TYPE_INT64:
+        case SD_BUS_TYPE_UINT64:
+        case SD_BUS_TYPE_DOUBLE:
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_OBJECT_PATH:
+        case SD_BUS_TYPE_SIGNATURE:
+        case SD_BUS_TYPE_UNIX_FD:
+
+                r = sd_bus_message_read_basic(m, *types, NULL);
+                if (r <= 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, types + 1);
+                if (r < 0)
+                        return r;
+
+                return 1;
+
+        case SD_BUS_TYPE_ARRAY: {
+                size_t k;
+
+                r = signature_element_length(types + 1, &k);
+                if (r < 0)
+                        return r;
+
+                {
+                        char s[k+1];
+                        memcpy(s, types+1, k);
+                        s[k] = 0;
+
+                        r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, s);
+                        if (r <= 0)
+                                return r;
+
+                        for (;;) {
+                                r = sd_bus_message_skip(m, s);
+                                if (r < 0)
+                                        return r;
+                                if (r == 0)
+                                        break;
+                        }
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = sd_bus_message_skip(m, types + 1 + k);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        case SD_BUS_TYPE_VARIANT: {
+                const char *contents;
+                char x;
+
+                r = sd_bus_message_peek_type(m, &x, &contents);
+                if (r <= 0)
+                        return r;
+
+                if (x != SD_BUS_TYPE_VARIANT)
+                        return -ENXIO;
+
+                r = sd_bus_message_enter_container(m, SD_BUS_TYPE_VARIANT, contents);
+                if (r <= 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, contents);
+                if (r < 0)
+                        return r;
+                assert(r != 0);
+
+                r = sd_bus_message_exit_container(m);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_skip(m, types + 1);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        case SD_BUS_TYPE_STRUCT_BEGIN:
+        case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
+                size_t k;
+
+                r = signature_element_length(types, &k);
+                if (r < 0)
+                        return r;
+
+                {
+                        char s[k-1];
+                        memcpy(s, types+1, k-2);
+                        s[k-2] = 0;
+
+                        r = sd_bus_message_enter_container(m, *types == SD_BUS_TYPE_STRUCT_BEGIN ? SD_BUS_TYPE_STRUCT : SD_BUS_TYPE_DICT_ENTRY, s);
+                        if (r <= 0)
+                                return r;
+
+                        r = sd_bus_message_skip(m, s);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+                }
+
+                r = sd_bus_message_skip(m, types + k);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        default:
+                return -EINVAL;
+        }
+}
+
+_public_ int sd_bus_message_read_array(
+                sd_bus_message *m,
+                char type,
+                const void **ptr,
+                size_t *size) {
+
+        struct bus_container *c;
+        void *p;
+        size_t sz;
+        ssize_t align;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(bus_type_is_trivial(type), -EINVAL);
+        assert_return(ptr, -EINVAL);
+        assert_return(size, -EINVAL);
+        assert_return(!BUS_MESSAGE_NEED_BSWAP(m), -EOPNOTSUPP);
+
+        r = sd_bus_message_enter_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                *ptr = NULL;
+                *size = 0;
+                return 0;
+        }
+
+        c = message_get_last_container(m);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                align = bus_gvariant_get_alignment(CHAR_TO_STR(type));
+                if (align < 0)
+                        return align;
+
+                sz = c->end - c->begin;
+        } else {
+                align = bus_type_get_alignment(type);
+                if (align < 0)
+                        return align;
+
+                sz = BUS_MESSAGE_BSWAP32(m, *c->array_size);
+        }
+
+        if (sz == 0)
+                /* Zero length array, let's return some aligned
+                 * pointer that is not NULL */
+                p = (uint8_t*) align;
+        else {
+                r = message_peek_body(m, &m->rindex, align, sz, &p);
+                if (r < 0)
+                        goto fail;
+        }
+
+        r = sd_bus_message_exit_container(m);
+        if (r < 0)
+                goto fail;
+
+        *ptr = (const void*) p;
+        *size = sz;
+
+        return 1;
+
+fail:
+        message_quit_container(m);
+        return r;
+}
+
+static int message_peek_fields(
+                sd_bus_message *m,
+                size_t *rindex,
+                size_t align,
+                size_t nbytes,
+                void **ret) {
+
+        assert(m);
+        assert(rindex);
+        assert(align > 0);
+
+        return buffer_peek(BUS_MESSAGE_FIELDS(m), m->fields_size, rindex, align, nbytes, ret);
+}
+
+static int message_peek_field_uint32(
+                sd_bus_message *m,
+                size_t *ri,
+                size_t item_size,
+                uint32_t *ret) {
+
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m) && item_size != 4)
+                return -EBADMSG;
+
+        /* identical for gvariant and dbus1 */
+
+        r = message_peek_fields(m, ri, 4, 4, &q);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+
+        return 0;
+}
+
+static int message_peek_field_uint64(
+                sd_bus_message *m,
+                size_t *ri,
+                size_t item_size,
+                uint64_t *ret) {
+
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m) && item_size != 8)
+                return -EBADMSG;
+
+        /* identical for gvariant and dbus1 */
+
+        r = message_peek_fields(m, ri, 8, 8, &q);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = BUS_MESSAGE_BSWAP64(m, *(uint64_t*) q);
+
+        return 0;
+}
+
+static int message_peek_field_string(
+                sd_bus_message *m,
+                bool (*validate)(const char *p),
+                size_t *ri,
+                size_t item_size,
+                const char **ret) {
+
+        uint32_t l;
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+
+                if (item_size <= 0)
+                        return -EBADMSG;
+
+                r = message_peek_fields(m, ri, 1, item_size, &q);
+                if (r < 0)
+                        return r;
+
+                l = item_size - 1;
+        } else {
+                r = message_peek_field_uint32(m, ri, 4, &l);
+                if (r < 0)
+                        return r;
+
+                if (l == UINT32_MAX)
+                        /* avoid overflow right below */
+                        return -EBADMSG;
+
+                r = message_peek_fields(m, ri, 1, l+1, &q);
+                if (r < 0)
+                        return r;
+        }
+
+        if (validate) {
+                if (!validate_nul(q, l))
+                        return -EBADMSG;
+
+                if (!validate(q))
+                        return -EBADMSG;
+        } else {
+                if (!validate_string(q, l))
+                        return -EBADMSG;
+        }
+
+        if (ret)
+                *ret = q;
+
+        return 0;
+}
+
+static int message_peek_field_signature(
+                sd_bus_message *m,
+                size_t *ri,
+                size_t item_size,
+                const char **ret) {
+
+        size_t l;
+        int r;
+        void *q;
+
+        assert(m);
+        assert(ri);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+
+                if (item_size <= 0)
+                        return -EBADMSG;
+
+                r = message_peek_fields(m, ri, 1, item_size, &q);
+                if (r < 0)
+                        return r;
+
+                l = item_size - 1;
+        } else {
+                r = message_peek_fields(m, ri, 1, 1, &q);
+                if (r < 0)
+                        return r;
+
+                l = *(uint8_t*) q;
+                if (l == UINT8_MAX)
+                        /* avoid overflow right below */
+                        return -EBADMSG;
+
+                r = message_peek_fields(m, ri, 1, l+1, &q);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!validate_signature(q, l))
+                return -EBADMSG;
+
+        if (ret)
+                *ret = q;
+
+        return 0;
+}
+
+static int message_skip_fields(
+                sd_bus_message *m,
+                size_t *ri,
+                uint32_t array_size,
+                const char **signature) {
+
+        size_t original_index;
+        int r;
+
+        assert(m);
+        assert(ri);
+        assert(signature);
+        assert(!BUS_MESSAGE_IS_GVARIANT(m));
+
+        original_index = *ri;
+
+        for (;;) {
+                char t;
+                size_t l;
+
+                if (array_size != (uint32_t) -1 &&
+                    array_size <= *ri - original_index)
+                        return 0;
+
+                t = **signature;
+                if (!t)
+                        return 0;
+
+                if (t == SD_BUS_TYPE_STRING) {
+
+                        r = message_peek_field_string(m, NULL, ri, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (t == SD_BUS_TYPE_OBJECT_PATH) {
+
+                        r = message_peek_field_string(m, object_path_is_valid, ri, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (t == SD_BUS_TYPE_SIGNATURE) {
+
+                        r = message_peek_field_signature(m, ri, 0, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (bus_type_is_basic(t)) {
+                        ssize_t align, k;
+
+                        align = bus_type_get_alignment(t);
+                        k = bus_type_get_size(t);
+                        assert(align > 0 && k > 0);
+
+                        r = message_peek_fields(m, ri, align, k, NULL);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (t == SD_BUS_TYPE_ARRAY) {
+
+                        r = signature_element_length(*signature + 1, &l);
+                        if (r < 0)
+                                return r;
+
+                        assert(l >= 1);
+                        {
+                                char sig[l + 1], *s = sig;
+                                uint32_t nas;
+                                int alignment;
+
+                                strncpy(sig, *signature + 1, l);
+                                sig[l] = '\0';
+
+                                alignment = bus_type_get_alignment(sig[0]);
+                                if (alignment < 0)
+                                        return alignment;
+
+                                r = message_peek_field_uint32(m, ri, 0, &nas);
+                                if (r < 0)
+                                        return r;
+                                if (nas > BUS_ARRAY_MAX_SIZE)
+                                        return -EBADMSG;
+
+                                r = message_peek_fields(m, ri, alignment, 0, NULL);
+                                if (r < 0)
+                                        return r;
+
+                                r = message_skip_fields(m, ri, nas, (const char**) &s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        (*signature) += 1 + l;
+
+                } else if (t == SD_BUS_TYPE_VARIANT) {
+                        const char *s;
+
+                        r = message_peek_field_signature(m, ri, 0, &s);
+                        if (r < 0)
+                                return r;
+
+                        r = message_skip_fields(m, ri, (uint32_t) -1, (const char**) &s);
+                        if (r < 0)
+                                return r;
+
+                        (*signature)++;
+
+                } else if (IN_SET(t, SD_BUS_TYPE_STRUCT, SD_BUS_TYPE_DICT_ENTRY)) {
+
+                        r = signature_element_length(*signature, &l);
+                        if (r < 0)
+                                return r;
+
+                        assert(l >= 2);
+                        {
+                                char sig[l + 1], *s = sig;
+                                strncpy(sig, *signature + 1, l);
+                                sig[l] = '\0';
+
+                                r = message_skip_fields(m, ri, (uint32_t) -1, (const char**) &s);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        *signature += l;
+                } else
+                        return -EBADMSG;
+        }
+}
+
+int bus_message_parse_fields(sd_bus_message *m) {
+        size_t ri;
+        int r;
+        uint32_t unix_fds = 0;
+        bool unix_fds_set = false;
+        void *offsets = NULL;
+        unsigned n_offsets = 0;
+        size_t sz = 0;
+        unsigned i = 0;
+
+        assert(m);
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                char *p;
+
+                /* Read the signature from the end of the body variant first */
+                sz = bus_gvariant_determine_word_size(BUS_MESSAGE_SIZE(m), 0);
+                if (m->footer_accessible < 1 + sz)
+                        return -EBADMSG;
+
+                p = (char*) m->footer + m->footer_accessible - (1 + sz);
+                for (;;) {
+                        if (p < (char*) m->footer)
+                                return -EBADMSG;
+
+                        if (*p == 0) {
+                                _cleanup_free_ char *k = NULL;
+                                size_t l;
+
+                                /* We found the beginning of the signature
+                                 * string, yay! We require the body to be a
+                                 * structure, so verify it and then strip the
+                                 * opening/closing brackets. */
+
+                                l = (char*) m->footer + m->footer_accessible - p - (1 + sz);
+                                if (l < 2 ||
+                                    p[1] != SD_BUS_TYPE_STRUCT_BEGIN ||
+                                    p[1 + l - 1] != SD_BUS_TYPE_STRUCT_END)
+                                        return -EBADMSG;
+
+                                k = memdup_suffix0(p + 1 + 1, l - 2);
+                                if (!k)
+                                        return -ENOMEM;
+
+                                if (!signature_is_valid(k, true))
+                                        return -EBADMSG;
+
+                                free_and_replace(m->root_container.signature, k);
+                                break;
+                        }
+
+                        p--;
+                }
+
+                /* Calculate the actual user body size, by removing
+                 * the trailing variant signature and struct offset
+                 * table */
+                m->user_body_size = m->body_size - ((char*) m->footer + m->footer_accessible - p);
+
+                /* Pull out the offset table for the fields array, if any */
+                if (m->fields_size > 0) {
+                        sz = bus_gvariant_determine_word_size(m->fields_size, 0);
+                        if (sz > 0) {
+                                size_t framing;
+                                void *q;
+
+                                if (m->fields_size < sz)
+                                        return -EBADMSG;
+
+                                ri = m->fields_size - sz;
+                                r = message_peek_fields(m, &ri, 1, sz, &q);
+                                if (r < 0)
+                                        return r;
+
+                                framing = bus_gvariant_read_word_le(q, sz);
+                                if (framing >= m->fields_size - sz)
+                                        return -EBADMSG;
+                                if ((m->fields_size - framing) % sz != 0)
+                                        return -EBADMSG;
+
+                                ri = framing;
+                                r = message_peek_fields(m, &ri, 1, m->fields_size - framing, &offsets);
+                                if (r < 0)
+                                        return r;
+
+                                n_offsets = (m->fields_size - framing) / sz;
+                        }
+                }
+        } else
+                m->user_body_size = m->body_size;
+
+        ri = 0;
+        while (ri < m->fields_size) {
+                _cleanup_free_ char *sig = NULL;
+                const char *signature;
+                uint64_t field_type;
+                size_t item_size = (size_t) -1;
+
+                if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                        uint64_t *u64;
+
+                        if (i >= n_offsets)
+                                break;
+
+                        if (i == 0)
+                                ri = 0;
+                        else
+                                ri = ALIGN_TO(bus_gvariant_read_word_le((uint8_t*) offsets + (i-1)*sz, sz), 8);
+
+                        r = message_peek_fields(m, &ri, 8, 8, (void**) &u64);
+                        if (r < 0)
+                                return r;
+
+                        field_type = BUS_MESSAGE_BSWAP64(m, *u64);
+                } else {
+                        uint8_t *u8;
+
+                        r = message_peek_fields(m, &ri, 8, 1, (void**) &u8);
+                        if (r < 0)
+                                return r;
+
+                        field_type = *u8;
+                }
+
+                if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                        size_t where, end;
+                        char *b;
+                        void *q;
+
+                        end = bus_gvariant_read_word_le((uint8_t*) offsets + i*sz, sz);
+
+                        if (end < ri)
+                                return -EBADMSG;
+
+                        where = ri = ALIGN_TO(ri, 8);
+                        item_size = end - ri;
+                        r = message_peek_fields(m, &where, 1, item_size, &q);
+                        if (r < 0)
+                                return r;
+
+                        b = memrchr(q, 0, item_size);
+                        if (!b)
+                                return -EBADMSG;
+
+                        sig = memdup_suffix0(b+1, item_size - (b+1-(char*) q));
+                        if (!sig)
+                                return -ENOMEM;
+
+                        signature = sig;
+                        item_size = b - (char*) q;
+                } else {
+                        r = message_peek_field_signature(m, &ri, 0, &signature);
+                        if (r < 0)
+                                return r;
+                }
+
+                switch (field_type) {
+
+                case _BUS_MESSAGE_HEADER_INVALID:
+                        return -EBADMSG;
+
+                case BUS_MESSAGE_HEADER_PATH:
+
+                        if (m->path)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "o"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, object_path_is_valid, &ri, item_size, &m->path);
+                        break;
+
+                case BUS_MESSAGE_HEADER_INTERFACE:
+
+                        if (m->interface)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, interface_name_is_valid, &ri, item_size, &m->interface);
+                        break;
+
+                case BUS_MESSAGE_HEADER_MEMBER:
+
+                        if (m->member)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, member_name_is_valid, &ri, item_size, &m->member);
+                        break;
+
+                case BUS_MESSAGE_HEADER_ERROR_NAME:
+
+                        if (m->error.name)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, error_name_is_valid, &ri, item_size, &m->error.name);
+                        if (r >= 0)
+                                m->error._need_free = -1;
+
+                        break;
+
+                case BUS_MESSAGE_HEADER_DESTINATION:
+
+                        if (m->destination)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, service_name_is_valid, &ri, item_size, &m->destination);
+                        break;
+
+                case BUS_MESSAGE_HEADER_SENDER:
+
+                        if (m->sender)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "s"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_string(m, service_name_is_valid, &ri, item_size, &m->sender);
+
+                        if (r >= 0 && m->sender[0] == ':' && m->bus->bus_client) {
+                                m->creds.unique_name = (char*) m->sender;
+                                m->creds.mask |= SD_BUS_CREDS_UNIQUE_NAME & m->bus->creds_mask;
+                        }
+
+                        break;
+
+                case BUS_MESSAGE_HEADER_SIGNATURE: {
+                        const char *s;
+                        char *c;
+
+                        if (BUS_MESSAGE_IS_GVARIANT(m)) /* only applies to dbus1 */
+                                return -EBADMSG;
+
+                        if (m->root_container.signature)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "g"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_signature(m, &ri, item_size, &s);
+                        if (r < 0)
+                                return r;
+
+                        c = strdup(s);
+                        if (!c)
+                                return -ENOMEM;
+
+                        free_and_replace(m->root_container.signature, c);
+                        break;
+                }
+
+                case BUS_MESSAGE_HEADER_REPLY_SERIAL:
+
+                        if (m->reply_cookie != 0)
+                                return -EBADMSG;
+
+                        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                                /* 64bit on dbus2 */
+
+                                if (!streq(signature, "t"))
+                                        return -EBADMSG;
+
+                                r = message_peek_field_uint64(m, &ri, item_size, &m->reply_cookie);
+                                if (r < 0)
+                                        return r;
+                        } else {
+                                /* 32bit on dbus1 */
+                                uint32_t serial;
+
+                                if (!streq(signature, "u"))
+                                        return -EBADMSG;
+
+                                r = message_peek_field_uint32(m, &ri, item_size, &serial);
+                                if (r < 0)
+                                        return r;
+
+                                m->reply_cookie = serial;
+                        }
+
+                        if (m->reply_cookie == 0)
+                                return -EBADMSG;
+
+                        break;
+
+                case BUS_MESSAGE_HEADER_UNIX_FDS:
+                        if (unix_fds_set)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "u"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_uint32(m, &ri, item_size, &unix_fds);
+                        if (r < 0)
+                                return -EBADMSG;
+
+                        unix_fds_set = true;
+                        break;
+
+                default:
+                        if (!BUS_MESSAGE_IS_GVARIANT(m))
+                                r = message_skip_fields(m, &ri, (uint32_t) -1, (const char **) &signature);
+                }
+
+                if (r < 0)
+                        return r;
+
+                i++;
+        }
+
+        if (m->n_fds != unix_fds)
+                return -EBADMSG;
+
+        switch (m->header->type) {
+
+        case SD_BUS_MESSAGE_SIGNAL:
+                if (!m->path || !m->interface || !m->member)
+                        return -EBADMSG;
+
+                if (m->reply_cookie != 0)
+                        return -EBADMSG;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_CALL:
+
+                if (!m->path || !m->member)
+                        return -EBADMSG;
+
+                if (m->reply_cookie != 0)
+                        return -EBADMSG;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_RETURN:
+
+                if (m->reply_cookie == 0)
+                        return -EBADMSG;
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_ERROR:
+
+                if (m->reply_cookie == 0 || !m->error.name)
+                        return -EBADMSG;
+                break;
+        }
+
+        /* Refuse non-local messages that claim they are local */
+        if (streq_ptr(m->path, "/org/freedesktop/DBus/Local"))
+                return -EBADMSG;
+        if (streq_ptr(m->interface, "org.freedesktop.DBus.Local"))
+                return -EBADMSG;
+        if (streq_ptr(m->sender, "org.freedesktop.DBus.Local"))
+                return -EBADMSG;
+
+        m->root_container.end = m->user_body_size;
+
+        if (BUS_MESSAGE_IS_GVARIANT(m)) {
+                r = build_struct_offsets(
+                                m,
+                                m->root_container.signature,
+                                m->user_body_size,
+                                &m->root_container.item_size,
+                                &m->root_container.offsets,
+                                &m->root_container.n_offsets);
+                if (r == -EINVAL)
+                        return -EBADMSG;
+                if (r < 0)
+                        return r;
+        }
+
+        /* Try to read the error message, but if we can't it's a non-issue */
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_ERROR)
+                (void) sd_bus_message_read(m, "s", &m->error.message);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_set_destination(sd_bus_message *m, const char *destination) {
+        assert_return(m, -EINVAL);
+        assert_return(destination, -EINVAL);
+        assert_return(service_name_is_valid(destination), -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->destination, -EEXIST);
+
+        return message_append_field_string(m, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, destination, &m->destination);
+}
+
+_public_ int sd_bus_message_set_sender(sd_bus_message *m, const char *sender) {
+        assert_return(m, -EINVAL);
+        assert_return(sender, -EINVAL);
+        assert_return(service_name_is_valid(sender), -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(!m->sender, -EEXIST);
+
+        return message_append_field_string(m, BUS_MESSAGE_HEADER_SENDER, SD_BUS_TYPE_STRING, sender, &m->sender);
+}
+
+int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz) {
+        size_t total;
+        void *p, *e;
+        size_t i;
+        struct bus_body_part *part;
+
+        assert(m);
+        assert(buffer);
+        assert(sz);
+
+        total = BUS_MESSAGE_SIZE(m);
+
+        p = malloc(total);
+        if (!p)
+                return -ENOMEM;
+
+        e = mempcpy(p, m->header, BUS_MESSAGE_BODY_BEGIN(m));
+        MESSAGE_FOREACH_PART(part, i, m)
+                e = mempcpy(e, part->data, part->size);
+
+        assert(total == (size_t) ((uint8_t*) e - (uint8_t*) p));
+
+        *buffer = p;
+        *sz = total;
+
+        return 0;
+}
+
+int bus_message_read_strv_extend(sd_bus_message *m, char ***l) {
+        const char *s;
+        int r;
+
+        assert(m);
+        assert(l);
+
+        r = sd_bus_message_enter_container(m, 'a', "s");
+        if (r <= 0)
+                return r;
+
+        while ((r = sd_bus_message_read_basic(m, 's', &s)) > 0) {
+                r = strv_extend(l, s);
+                if (r < 0)
+                        return r;
+        }
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_exit_container(m);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+_public_ int sd_bus_message_read_strv(sd_bus_message *m, char ***l) {
+        _cleanup_strv_free_ char **strv = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(l, -EINVAL);
+
+        r = bus_message_read_strv_extend(m, &strv);
+        if (r <= 0)
+                return r;
+
+        *l = TAKE_PTR(strv);
+        return 1;
+}
+
+static int bus_message_get_arg_skip(
+                sd_bus_message *m,
+                unsigned i,
+                char *_type,
+                const char **_contents) {
+
+        unsigned j;
+        int r;
+
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        for (j = 0;; j++) {
+                const char *contents;
+                char type;
+
+                r = sd_bus_message_peek_type(m, &type, &contents);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -ENXIO;
+
+                /* Don't match against arguments after the first one we don't understand */
+                if (!IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE) &&
+                    !(type == SD_BUS_TYPE_ARRAY && STR_IN_SET(contents, "s", "o", "g")))
+                        return -ENXIO;
+
+                if (j >= i) {
+                        if (_contents)
+                                *_contents = contents;
+                        if (_type)
+                                *_type = type;
+                        return 0;
+                }
+
+                r = sd_bus_message_skip(m, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+}
+
+int bus_message_get_arg(sd_bus_message *m, unsigned i, const char **str) {
+        char type;
+        int r;
+
+        assert(m);
+        assert(str);
+
+        r = bus_message_get_arg_skip(m, i, &type, NULL);
+        if (r < 0)
+                return r;
+
+        if (!IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE))
+                return -ENXIO;
+
+        return sd_bus_message_read_basic(m, type, str);
+}
+
+int bus_message_get_arg_strv(sd_bus_message *m, unsigned i, char ***strv) {
+        const char *contents;
+        char type;
+        int r;
+
+        assert(m);
+        assert(strv);
+
+        r = bus_message_get_arg_skip(m, i, &type, &contents);
+        if (r < 0)
+                return r;
+
+        if (type != SD_BUS_TYPE_ARRAY)
+                return -ENXIO;
+        if (!STR_IN_SET(contents, "s", "o", "g"))
+                return -ENXIO;
+
+        return sd_bus_message_read_strv(m, strv);
+}
+
+_public_ int sd_bus_message_get_errno(sd_bus_message *m) {
+        assert_return(m, EINVAL);
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_ERROR)
+                return 0;
+
+        return sd_bus_error_get_errno(&m->error);
+}
+
+_public_ const char* sd_bus_message_get_signature(sd_bus_message *m, int complete) {
+        struct bus_container *c;
+
+        assert_return(m, NULL);
+
+        c = complete ? &m->root_container : message_get_last_container(m);
+        return strempty(c->signature);
+}
+
+_public_ int sd_bus_message_is_empty(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        return isempty(m->root_container.signature);
+}
+
+_public_ int sd_bus_message_has_signature(sd_bus_message *m, const char *signature) {
+        assert_return(m, -EINVAL);
+
+        return streq(strempty(m->root_container.signature), strempty(signature));
+}
+
+_public_ int sd_bus_message_copy(sd_bus_message *m, sd_bus_message *source, int all) {
+        bool done_something = false;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(source, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(source->sealed, -EPERM);
+
+        do {
+                const char *contents;
+                char type;
+                union {
+                        uint8_t u8;
+                        uint16_t u16;
+                        int16_t s16;
+                        uint32_t u32;
+                        int32_t s32;
+                        uint64_t u64;
+                        int64_t s64;
+                        double d64;
+                        const char *string;
+                        int i;
+                } basic;
+
+                r = sd_bus_message_peek_type(source, &type, &contents);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                done_something = true;
+
+                if (bus_type_is_container(type) > 0) {
+
+                        r = sd_bus_message_enter_container(source, type, contents);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_open_container(m, type, contents);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_copy(m, source, true);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_close_container(m);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_exit_container(source);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                r = sd_bus_message_read_basic(source, type, &basic);
+                if (r < 0)
+                        return r;
+
+                assert(r > 0);
+
+                if (IN_SET(type, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE, SD_BUS_TYPE_STRING))
+                        r = sd_bus_message_append_basic(m, type, basic.string);
+                else
+                        r = sd_bus_message_append_basic(m, type, &basic);
+
+                if (r < 0)
+                        return r;
+
+        } while (all);
+
+        return done_something;
+}
+
+_public_ int sd_bus_message_verify_type(sd_bus_message *m, char type, const char *contents) {
+        const char *c;
+        char t;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(!type || bus_type_is_valid(type), -EINVAL);
+        assert_return(!contents || signature_is_valid(contents, true), -EINVAL);
+        assert_return(type || contents, -EINVAL);
+        assert_return(!contents || !type || bus_type_is_container(type), -EINVAL);
+
+        r = sd_bus_message_peek_type(m, &t, &c);
+        if (r <= 0)
+                return r;
+
+        if (type != 0 && type != t)
+                return 0;
+
+        if (contents && !streq_ptr(contents, c))
+                return 0;
+
+        return 1;
+}
+
+_public_ sd_bus *sd_bus_message_get_bus(sd_bus_message *m) {
+        assert_return(m, NULL);
+
+        return m->bus;
+}
+
+int bus_message_remarshal(sd_bus *bus, sd_bus_message **m) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *n = NULL;
+        usec_t timeout;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(*m);
+
+        switch ((*m)->header->type) {
+
+        case SD_BUS_MESSAGE_SIGNAL:
+                r = sd_bus_message_new_signal(bus, &n, (*m)->path, (*m)->interface, (*m)->member);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_CALL:
+                r = sd_bus_message_new_method_call(bus, &n, (*m)->destination, (*m)->path, (*m)->interface, (*m)->member);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        case SD_BUS_MESSAGE_METHOD_RETURN:
+        case SD_BUS_MESSAGE_METHOD_ERROR:
+
+                r = sd_bus_message_new(bus, &n, (*m)->header->type);
+                if (r < 0)
+                        return -ENOMEM;
+
+                assert(n);
+
+                n->reply_cookie = (*m)->reply_cookie;
+
+                r = message_append_reply_cookie(n, n->reply_cookie);
+                if (r < 0)
+                        return r;
+
+                if ((*m)->header->type == SD_BUS_MESSAGE_METHOD_ERROR && (*m)->error.name) {
+                        r = message_append_field_string(n, BUS_MESSAGE_HEADER_ERROR_NAME, SD_BUS_TYPE_STRING, (*m)->error.name, &n->error.message);
+                        if (r < 0)
+                                return r;
+
+                        n->error._need_free = -1;
+                }
+
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        if ((*m)->destination && !n->destination) {
+                r = message_append_field_string(n, BUS_MESSAGE_HEADER_DESTINATION, SD_BUS_TYPE_STRING, (*m)->destination, &n->destination);
+                if (r < 0)
+                        return r;
+        }
+
+        if ((*m)->sender && !n->sender) {
+                r = message_append_field_string(n, BUS_MESSAGE_HEADER_SENDER, SD_BUS_TYPE_STRING, (*m)->sender, &n->sender);
+                if (r < 0)
+                        return r;
+        }
+
+        n->header->flags |= (*m)->header->flags & (BUS_MESSAGE_NO_REPLY_EXPECTED|BUS_MESSAGE_NO_AUTO_START);
+
+        r = sd_bus_message_copy(n, *m, true);
+        if (r < 0)
+                return r;
+
+        timeout = (*m)->timeout;
+        if (timeout == 0 && !((*m)->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)) {
+                r = sd_bus_get_method_call_timeout(bus, &timeout);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_message_seal(n, BUS_MESSAGE_COOKIE(*m), timeout);
+        if (r < 0)
+                return r;
+
+        sd_bus_message_unref(*m);
+        *m = TAKE_PTR(n);
+
+        return 0;
+}
+
+_public_ int sd_bus_message_get_priority(sd_bus_message *m, int64_t *priority) {
+        static bool warned = false;
+
+        assert_return(m, -EINVAL);
+        assert_return(priority, -EINVAL);
+
+        if (!warned) {
+                log_debug("sd_bus_message_get_priority() is deprecated and always returns 0.");
+                warned = true;
+        }
+
+        *priority = 0;
+        return 0;
+}
+
+_public_ int sd_bus_message_set_priority(sd_bus_message *m, int64_t priority) {
+        static bool warned = false;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        if (!warned) {
+                log_debug("sd_bus_message_set_priority() is deprecated and does nothing.");
+                warned = true;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_message_sensitive(sd_bus_message *m) {
+        assert_return(m, -EINVAL);
+
+        m->sensitive = true;
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/bus-message.h b/src/libsystemd/sd-bus/bus-message.h
new file mode 100644
index 0000000..3561737
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-message.h
@@ -0,0 +1,227 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <byteswap.h>
+#include <stdbool.h>
+#include <sys/socket.h>
+
+#include "sd-bus.h"
+
+#include "bus-creds.h"
+#include "bus-protocol.h"
+#include "macro.h"
+#include "time-util.h"
+
+struct bus_container {
+        char enclosing;
+        bool need_offsets:1;
+
+        /* Indexes into the signature  string */
+        unsigned index, saved_index;
+        char *signature;
+
+        size_t before, begin, end;
+
+        /* dbus1: pointer to the array size value, if this is a value */
+        uint32_t *array_size;
+
+        /* gvariant: list of offsets to end of children if this is struct/dict entry/array */
+        size_t *offsets, n_offsets, offsets_allocated, offset_index;
+        size_t item_size;
+
+        char *peeked_signature;
+};
+
+struct bus_body_part {
+        struct bus_body_part *next;
+        void *data;
+        void *mmap_begin;
+        size_t size;
+        size_t mapped;
+        size_t allocated;
+        uint64_t memfd_offset;
+        int memfd;
+        bool free_this:1;
+        bool munmap_this:1;
+        bool sealed:1;
+        bool is_zero:1;
+};
+
+struct sd_bus_message {
+        /* Caveat: a message can be referenced in two different ways: the main (user-facing) way will also
+         * pin the bus connection object the message is associated with. The secondary way ("queued") is used
+         * when a message is in the read or write queues of the bus connection object, which will not pin the
+         * bus connection object. This is necessary so that we don't have to have a pair of cyclic references
+         * between a message that is queued and its connection: as soon as a message is only referenced by
+         * the connection (by means of being queued) and the connection itself has no other references it
+         * will be freed. */
+
+        unsigned n_ref;     /* Counter of references that pin the connection */
+        unsigned n_queued;  /* Counter of references that do not pin the connection */
+
+        sd_bus *bus;
+
+        uint64_t reply_cookie;
+
+        const char *path;
+        const char *interface;
+        const char *member;
+        const char *destination;
+        const char *sender;
+
+        sd_bus_error error;
+
+        sd_bus_creds creds;
+
+        usec_t monotonic;
+        usec_t realtime;
+        uint64_t seqnum;
+        uint64_t verify_destination_id;
+
+        bool sealed:1;
+        bool dont_send:1;
+        bool allow_fds:1;
+        bool free_header:1;
+        bool free_fds:1;
+        bool poisoned:1;
+        bool sensitive:1;
+
+        /* The first and last bytes of the message */
+        struct bus_header *header;
+        void *footer;
+
+        /* How many bytes are accessible in the above pointers */
+        size_t header_accessible;
+        size_t footer_accessible;
+
+        size_t fields_size;
+        size_t body_size;
+        size_t user_body_size;
+
+        struct bus_body_part body;
+        struct bus_body_part *body_end;
+        unsigned n_body_parts;
+
+        size_t rindex;
+        struct bus_body_part *cached_rindex_part;
+        size_t cached_rindex_part_begin;
+
+        uint32_t n_fds;
+        int *fds;
+
+        struct bus_container root_container, *containers;
+        size_t n_containers;
+        size_t containers_allocated;
+
+        struct iovec *iovec;
+        struct iovec iovec_fixed[2];
+        unsigned n_iovec;
+
+        char *peeked_signature;
+
+        /* If set replies to this message must carry the signature
+         * specified here to successfully seal. This is initialized
+         * from the vtable data */
+        const char *enforced_reply_signature;
+
+        usec_t timeout;
+
+        size_t header_offsets[_BUS_MESSAGE_HEADER_MAX];
+        unsigned n_header_offsets;
+
+        uint64_t read_counter;
+};
+
+static inline bool BUS_MESSAGE_NEED_BSWAP(sd_bus_message *m) {
+        return m->header->endian != BUS_NATIVE_ENDIAN;
+}
+
+static inline uint16_t BUS_MESSAGE_BSWAP16(sd_bus_message *m, uint16_t u) {
+        return BUS_MESSAGE_NEED_BSWAP(m) ? bswap_16(u) : u;
+}
+
+static inline uint32_t BUS_MESSAGE_BSWAP32(sd_bus_message *m, uint32_t u) {
+        return BUS_MESSAGE_NEED_BSWAP(m) ? bswap_32(u) : u;
+}
+
+static inline uint64_t BUS_MESSAGE_BSWAP64(sd_bus_message *m, uint64_t u) {
+        return BUS_MESSAGE_NEED_BSWAP(m) ? bswap_64(u) : u;
+}
+
+static inline uint64_t BUS_MESSAGE_COOKIE(sd_bus_message *m) {
+        if (m->header->version == 2)
+                return BUS_MESSAGE_BSWAP64(m, m->header->dbus2.cookie);
+
+        return BUS_MESSAGE_BSWAP32(m, m->header->dbus1.serial);
+}
+
+static inline size_t BUS_MESSAGE_SIZE(sd_bus_message *m) {
+        return
+                sizeof(struct bus_header) +
+                ALIGN8(m->fields_size) +
+                m->body_size;
+}
+
+static inline size_t BUS_MESSAGE_BODY_BEGIN(sd_bus_message *m) {
+        return
+                sizeof(struct bus_header) +
+                ALIGN8(m->fields_size);
+}
+
+static inline void* BUS_MESSAGE_FIELDS(sd_bus_message *m) {
+        return (uint8_t*) m->header + sizeof(struct bus_header);
+}
+
+static inline bool BUS_MESSAGE_IS_GVARIANT(sd_bus_message *m) {
+        return m->header->version == 2;
+}
+
+int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz);
+int bus_message_read_strv_extend(sd_bus_message *m, char ***l);
+
+int bus_message_from_header(
+                sd_bus *bus,
+                void *header,
+                size_t header_accessible,
+                void *footer,
+                size_t footer_accessible,
+                size_t message_size,
+                int *fds,
+                size_t n_fds,
+                const char *label,
+                size_t extra,
+                sd_bus_message **ret);
+
+int bus_message_from_malloc(
+                sd_bus *bus,
+                void *buffer,
+                size_t length,
+                int *fds,
+                size_t n_fds,
+                const char *label,
+                sd_bus_message **ret);
+
+int bus_message_get_arg(sd_bus_message *m, unsigned i, const char **str);
+int bus_message_get_arg_strv(sd_bus_message *m, unsigned i, char ***strv);
+
+int bus_message_parse_fields(sd_bus_message *m);
+
+struct bus_body_part *message_append_part(sd_bus_message *m);
+
+#define MESSAGE_FOREACH_PART(part, i, m) \
+        for ((i) = 0, (part) = &(m)->body; (i) < (m)->n_body_parts; (i)++, (part) = (part)->next)
+
+int bus_body_part_map(struct bus_body_part *part);
+void bus_body_part_unmap(struct bus_body_part *part);
+
+int bus_message_to_errno(sd_bus_message *m);
+
+int bus_message_new_synthetic_error(sd_bus *bus, uint64_t serial, const sd_bus_error *e, sd_bus_message **m);
+
+int bus_message_remarshal(sd_bus *bus, sd_bus_message **m);
+
+void bus_message_set_sender_driver(sd_bus *bus, sd_bus_message *m);
+void bus_message_set_sender_local(sd_bus *bus, sd_bus_message *m);
+
+sd_bus_message* bus_message_ref_queued(sd_bus_message *m, sd_bus *bus);
+sd_bus_message* bus_message_unref_queued(sd_bus_message *m, sd_bus *bus);
diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
new file mode 100644
index 0000000..275c431
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -0,0 +1,3031 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-introspect.h"
+#include "bus-message.h"
+#include "bus-objects.h"
+#include "bus-signature.h"
+#include "bus-slot.h"
+#include "bus-type.h"
+#include "bus-util.h"
+#include "missing_capability.h"
+#include "set.h"
+#include "string-util.h"
+#include "strv.h"
+
+static int node_vtable_get_userdata(
+                sd_bus *bus,
+                const char *path,
+                struct node_vtable *c,
+                void **userdata,
+                sd_bus_error *error) {
+
+        sd_bus_slot *s;
+        void *u, *found_u = NULL;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(c);
+
+        s = container_of(c, sd_bus_slot, node_vtable);
+        u = s->userdata;
+        if (c->find) {
+                bus->current_slot = sd_bus_slot_ref(s);
+                bus->current_userdata = u;
+                r = c->find(bus, path, c->interface, u, &found_u, error);
+                bus->current_userdata = NULL;
+                bus->current_slot = sd_bus_slot_unref(s);
+
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return -sd_bus_error_get_errno(error);
+                if (r == 0)
+                        return r;
+        } else
+                found_u = u;
+
+        if (userdata)
+                *userdata = found_u;
+
+        return 1;
+}
+
+static void *vtable_method_convert_userdata(const sd_bus_vtable *p, void *u) {
+        assert(p);
+
+        if (!u || FLAGS_SET(p->flags, SD_BUS_VTABLE_ABSOLUTE_OFFSET))
+                return SIZE_TO_PTR(p->x.method.offset); /* don't add offset on NULL, to make ubsan happy */
+
+        return (uint8_t*) u + p->x.method.offset;
+}
+
+static void *vtable_property_convert_userdata(const sd_bus_vtable *p, void *u) {
+        assert(p);
+
+        if (!u || FLAGS_SET(p->flags, SD_BUS_VTABLE_ABSOLUTE_OFFSET))
+                return SIZE_TO_PTR(p->x.property.offset); /* as above */
+
+        return (uint8_t*) u + p->x.property.offset;
+}
+
+static int vtable_property_get_userdata(
+                sd_bus *bus,
+                const char *path,
+                struct vtable_member *p,
+                void **userdata,
+                sd_bus_error *error) {
+
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(p);
+        assert(userdata);
+
+        r = node_vtable_get_userdata(bus, path, p->parent, &u, error);
+        if (r <= 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        *userdata = vtable_property_convert_userdata(p->vtable, u);
+        return 1;
+}
+
+static int add_enumerated_to_set(
+                sd_bus *bus,
+                const char *prefix,
+                struct node_enumerator *first,
+                Set *s,
+                sd_bus_error *error) {
+
+        struct node_enumerator *c;
+        int r;
+
+        assert(bus);
+        assert(prefix);
+        assert(s);
+
+        LIST_FOREACH(enumerators, c, first) {
+                char **children = NULL, **k;
+                sd_bus_slot *slot;
+
+                if (bus->nodes_modified)
+                        return 0;
+
+                slot = container_of(c, sd_bus_slot, node_enumerator);
+
+                bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_userdata = slot->userdata;
+                r = c->callback(bus, prefix, slot->userdata, &children, error);
+                bus->current_userdata = NULL;
+                bus->current_slot = sd_bus_slot_unref(slot);
+
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return -sd_bus_error_get_errno(error);
+
+                STRV_FOREACH(k, children) {
+                        if (r < 0) {
+                                free(*k);
+                                continue;
+                        }
+
+                        if (!object_path_is_valid(*k)) {
+                                free(*k);
+                                r = -EINVAL;
+                                continue;
+                        }
+
+                        if (!object_path_startswith(*k, prefix)) {
+                                free(*k);
+                                continue;
+                        }
+
+                        r = set_consume(s, *k);
+                        if (r == -EEXIST)
+                                r = 0;
+                }
+
+                free(children);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+enum {
+        /* if set, add_subtree() works recursively */
+        CHILDREN_RECURSIVE      = 1 << 0,
+        /* if set, add_subtree() scans object-manager hierarchies recursively */
+        CHILDREN_SUBHIERARCHIES = 1 << 1,
+};
+
+static int add_subtree_to_set(
+                sd_bus *bus,
+                const char *prefix,
+                struct node *n,
+                unsigned flags,
+                Set *s,
+                sd_bus_error *error) {
+
+        struct node *i;
+        int r;
+
+        assert(bus);
+        assert(prefix);
+        assert(n);
+        assert(s);
+
+        r = add_enumerated_to_set(bus, prefix, n->enumerators, s, error);
+        if (r < 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        LIST_FOREACH(siblings, i, n->child) {
+                char *t;
+
+                if (!object_path_startswith(i->path, prefix))
+                        continue;
+
+                t = strdup(i->path);
+                if (!t)
+                        return -ENOMEM;
+
+                r = set_consume(s, t);
+                if (r < 0 && r != -EEXIST)
+                        return r;
+
+                if ((flags & CHILDREN_RECURSIVE) &&
+                    ((flags & CHILDREN_SUBHIERARCHIES) || !i->object_managers)) {
+                        r = add_subtree_to_set(bus, prefix, i, flags, s, error);
+                        if (r < 0)
+                                return r;
+                        if (bus->nodes_modified)
+                                return 0;
+                }
+        }
+
+        return 0;
+}
+
+static int get_child_nodes(
+                sd_bus *bus,
+                const char *prefix,
+                struct node *n,
+                unsigned flags,
+                Set **_s,
+                sd_bus_error *error) {
+
+        Set *s = NULL;
+        int r;
+
+        assert(bus);
+        assert(prefix);
+        assert(n);
+        assert(_s);
+
+        s = set_new(&string_hash_ops);
+        if (!s)
+                return -ENOMEM;
+
+        r = add_subtree_to_set(bus, prefix, n, flags, s, error);
+        if (r < 0) {
+                set_free_free(s);
+                return r;
+        }
+
+        *_s = s;
+        return 0;
+}
+
+static int node_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node_callback *first,
+                bool require_fallback,
+                bool *found_object) {
+
+        struct node_callback *c;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(found_object);
+
+        LIST_FOREACH(callbacks, c, first) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+                sd_bus_slot *slot;
+
+                if (bus->nodes_modified)
+                        return 0;
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                *found_object = true;
+
+                if (c->last_iteration == bus->iteration_counter)
+                        continue;
+
+                c->last_iteration = bus->iteration_counter;
+
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+
+                slot = container_of(c, sd_bus_slot, node_callback);
+
+                bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_handler = c->callback;
+                bus->current_userdata = slot->userdata;
+                r = c->callback(m, slot->userdata, &error_buffer);
+                bus->current_userdata = NULL;
+                bus->current_handler = NULL;
+                bus->current_slot = sd_bus_slot_unref(slot);
+
+                r = bus_maybe_reply_error(m, r, &error_buffer);
+                if (r != 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+#define CAPABILITY_SHIFT(x) (((x) >> __builtin_ctzll(_SD_BUS_VTABLE_CAPABILITY_MASK)) & 0xFFFF)
+
+static int check_access(sd_bus *bus, sd_bus_message *m, struct vtable_member *c, sd_bus_error *error) {
+        uint64_t cap;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(c);
+
+        /* If the entire bus is trusted let's grant access */
+        if (bus->trusted)
+                return 0;
+
+        /* If the member is marked UNPRIVILEGED let's grant access */
+        if (c->vtable->flags & SD_BUS_VTABLE_UNPRIVILEGED)
+                return 0;
+
+        /* Check have the caller has the requested capability
+         * set. Note that the flags value contains the capability
+         * number plus one, which we need to subtract here. We do this
+         * so that we have 0 as special value for "default
+         * capability". */
+        cap = CAPABILITY_SHIFT(c->vtable->flags);
+        if (cap == 0)
+                cap = CAPABILITY_SHIFT(c->parent->vtable[0].flags);
+        if (cap == 0)
+                cap = CAP_SYS_ADMIN;
+        else
+                cap--;
+
+        r = sd_bus_query_sender_privilege(m, cap);
+        if (r < 0)
+                return r;
+        if (r > 0)
+                return 0;
+
+        return sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Access to %s.%s() not permitted.", c->interface, c->member);
+}
+
+static int method_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct vtable_member *c,
+                bool require_fallback,
+                bool *found_object) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        const char *signature;
+        void *u;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(c);
+        assert(found_object);
+
+        if (require_fallback && !c->parent->is_fallback)
+                return 0;
+
+        if (FLAGS_SET(c->vtable->flags, SD_BUS_VTABLE_SENSITIVE)) {
+                r = sd_bus_message_sensitive(m);
+                if (r < 0)
+                        return r;
+        }
+
+        r = check_access(bus, m, c, &error);
+        if (r < 0)
+                return bus_maybe_reply_error(m, r, &error);
+
+        r = node_vtable_get_userdata(bus, m->path, c->parent, &u, &error);
+        if (r <= 0)
+                return bus_maybe_reply_error(m, r, &error);
+        if (bus->nodes_modified)
+                return 0;
+
+        u = vtable_method_convert_userdata(c->vtable, u);
+
+        *found_object = true;
+
+        if (c->last_iteration == bus->iteration_counter)
+                return 0;
+
+        c->last_iteration = bus->iteration_counter;
+
+        r = sd_bus_message_rewind(m, true);
+        if (r < 0)
+                return r;
+
+        signature = sd_bus_message_get_signature(m, true);
+        if (!signature)
+                return -EINVAL;
+
+        if (!streq(strempty(c->vtable->x.method.signature), signature))
+                return sd_bus_reply_method_errorf(
+                                m,
+                                SD_BUS_ERROR_INVALID_ARGS,
+                                "Invalid arguments '%s' to call %s.%s(), expecting '%s'.",
+                                signature, c->interface, c->member, strempty(c->vtable->x.method.signature));
+
+        /* Keep track what the signature of the reply to this message
+         * should be, so that this can be enforced when sealing the
+         * reply. */
+        m->enforced_reply_signature = strempty(c->vtable->x.method.result);
+
+        if (c->vtable->x.method.handler) {
+                sd_bus_slot *slot;
+
+                slot = container_of(c->parent, sd_bus_slot, node_vtable);
+
+                bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_handler = c->vtable->x.method.handler;
+                bus->current_userdata = u;
+                r = c->vtable->x.method.handler(m, u, &error);
+                bus->current_userdata = NULL;
+                bus->current_handler = NULL;
+                bus->current_slot = sd_bus_slot_unref(slot);
+
+                return bus_maybe_reply_error(m, r, &error);
+        }
+
+        /* If the method callback is NULL, make this a successful NOP */
+        r = sd_bus_reply_method_return(m, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int invoke_property_get(
+                sd_bus *bus,
+                sd_bus_slot *slot,
+                const sd_bus_vtable *v,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *reply,
+                void *userdata,
+                sd_bus_error *error) {
+
+        const void *p;
+        int r;
+
+        assert(bus);
+        assert(slot);
+        assert(v);
+        assert(path);
+        assert(interface);
+        assert(property);
+        assert(reply);
+
+        if (v->x.property.get) {
+
+                bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_userdata = userdata;
+                r = v->x.property.get(bus, path, interface, property, reply, userdata, error);
+                bus->current_userdata = NULL;
+                bus->current_slot = sd_bus_slot_unref(slot);
+
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return -sd_bus_error_get_errno(error);
+                return r;
+        }
+
+        /* Automatic handling if no callback is defined. */
+
+        if (streq(v->x.property.signature, "as"))
+                return sd_bus_message_append_strv(reply, *(char***) userdata);
+
+        assert(signature_is_single(v->x.property.signature, false));
+        assert(bus_type_is_basic(v->x.property.signature[0]));
+
+        switch (v->x.property.signature[0]) {
+
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_SIGNATURE:
+                p = strempty(*(char**) userdata);
+                break;
+
+        case SD_BUS_TYPE_OBJECT_PATH:
+                p = *(char**) userdata;
+                assert(p);
+                break;
+
+        default:
+                p = userdata;
+                break;
+        }
+
+        return sd_bus_message_append_basic(reply, v->x.property.signature[0], p);
+}
+
+static int invoke_property_set(
+                sd_bus *bus,
+                sd_bus_slot *slot,
+                const sd_bus_vtable *v,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *value,
+                void *userdata,
+                sd_bus_error *error) {
+
+        int r;
+
+        assert(bus);
+        assert(slot);
+        assert(v);
+        assert(path);
+        assert(interface);
+        assert(property);
+        assert(value);
+
+        if (v->x.property.set) {
+
+                bus->current_slot = sd_bus_slot_ref(slot);
+                bus->current_userdata = userdata;
+                r = v->x.property.set(bus, path, interface, property, value, userdata, error);
+                bus->current_userdata = NULL;
+                bus->current_slot = sd_bus_slot_unref(slot);
+
+                if (r < 0)
+                        return r;
+                if (sd_bus_error_is_set(error))
+                        return -sd_bus_error_get_errno(error);
+                return r;
+        }
+
+        /*  Automatic handling if no callback is defined. */
+
+        assert(signature_is_single(v->x.property.signature, false));
+        assert(bus_type_is_basic(v->x.property.signature[0]));
+
+        switch (v->x.property.signature[0]) {
+
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_OBJECT_PATH:
+        case SD_BUS_TYPE_SIGNATURE: {
+                const char *p;
+                char *n;
+
+                r = sd_bus_message_read_basic(value, v->x.property.signature[0], &p);
+                if (r < 0)
+                        return r;
+
+                n = strdup(p);
+                if (!n)
+                        return -ENOMEM;
+
+                free(*(char**) userdata);
+                *(char**) userdata = n;
+
+                break;
+        }
+
+        default:
+                r = sd_bus_message_read_basic(value, v->x.property.signature[0], userdata);
+                if (r < 0)
+                        return r;
+
+                break;
+        }
+
+        return 1;
+}
+
+static int property_get_set_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct vtable_member *c,
+                bool require_fallback,
+                bool is_get,
+                bool *found_object) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        sd_bus_slot *slot;
+        void *u = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(c);
+        assert(found_object);
+
+        if (require_fallback && !c->parent->is_fallback)
+                return 0;
+
+        if (FLAGS_SET(c->vtable->flags, SD_BUS_VTABLE_SENSITIVE)) {
+                r = sd_bus_message_sensitive(m);
+                if (r < 0)
+                        return r;
+        }
+
+        r = vtable_property_get_userdata(bus, m->path, c, &u, &error);
+        if (r <= 0)
+                return bus_maybe_reply_error(m, r, &error);
+        if (bus->nodes_modified)
+                return 0;
+
+        slot = container_of(c->parent, sd_bus_slot, node_vtable);
+
+        *found_object = true;
+
+        r = sd_bus_message_new_method_return(m, &reply);
+        if (r < 0)
+                return r;
+
+        if (FLAGS_SET(c->vtable->flags, SD_BUS_VTABLE_SENSITIVE)) {
+                r = sd_bus_message_sensitive(reply);
+                if (r < 0)
+                        return r;
+        }
+
+        if (is_get) {
+                /* Note that we do not protect against reexecution
+                 * here (using the last_iteration check, see below),
+                 * should the node tree have changed and we got called
+                 * again. We assume that property Get() calls are
+                 * ultimately without side-effects or if they aren't
+                 * then at least idempotent. */
+
+                r = sd_bus_message_open_container(reply, 'v', c->vtable->x.property.signature);
+                if (r < 0)
+                        return r;
+
+                /* Note that we do not do an access check here. Read
+                 * access to properties is always unrestricted, since
+                 * PropertiesChanged signals broadcast contents
+                 * anyway. */
+
+                r = invoke_property_get(bus, slot, c->vtable, m->path, c->interface, c->member, reply, u, &error);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, &error);
+
+                if (bus->nodes_modified)
+                        return 0;
+
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+
+        } else {
+                const char *signature = NULL;
+                char type = 0;
+
+                if (c->vtable->type != _SD_BUS_VTABLE_WRITABLE_PROPERTY)
+                        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_PROPERTY_READ_ONLY, "Property '%s' is not writable.", c->member);
+
+                /* Avoid that we call the set routine more than once
+                 * if the processing of this message got restarted
+                 * because the node tree changed. */
+                if (c->last_iteration == bus->iteration_counter)
+                        return 0;
+
+                c->last_iteration = bus->iteration_counter;
+
+                r = sd_bus_message_peek_type(m, &type, &signature);
+                if (r < 0)
+                        return r;
+
+                if (type != 'v')
+                        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INVALID_SIGNATURE,
+                                                          "Incorrect signature when setting property '%s', expected 'v', got '%c'.",
+                                                          c->member, type);
+                if (!streq(strempty(signature), strempty(c->vtable->x.property.signature)))
+                        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INVALID_ARGS,
+                                                          "Incorrect parameters for property '%s', expected '%s', got '%s'.",
+                                                          c->member, strempty(c->vtable->x.property.signature), strempty(signature));
+
+                r = sd_bus_message_enter_container(m, 'v', c->vtable->x.property.signature);
+                if (r < 0)
+                        return r;
+
+                r = check_access(bus, m, c, &error);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, &error);
+
+                r = invoke_property_set(bus, slot, c->vtable, m->path, c->interface, c->member, m, u, &error);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, &error);
+
+                if (bus->nodes_modified)
+                        return 0;
+
+                r = sd_bus_message_exit_container(m);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int vtable_append_one_property(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                struct node_vtable *c,
+                const sd_bus_vtable *v,
+                void *userdata,
+                sd_bus_error *error) {
+
+        sd_bus_slot *slot;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(path);
+        assert(c);
+        assert(v);
+
+        if (FLAGS_SET(c->vtable->flags, SD_BUS_VTABLE_SENSITIVE)) {
+                r = sd_bus_message_sensitive(reply);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_message_open_container(reply, 'e', "sv");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(reply, "s", v->x.property.member);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'v', v->x.property.signature);
+        if (r < 0)
+                return r;
+
+        slot = container_of(c, sd_bus_slot, node_vtable);
+
+        r = invoke_property_get(bus, slot, v, path, c->interface, v->x.property.member, reply, vtable_property_convert_userdata(v, userdata), error);
+        if (r < 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int vtable_append_all_properties(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                struct node_vtable *c,
+                void *userdata,
+                sd_bus_error *error) {
+
+        const sd_bus_vtable *v;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(path);
+        assert(c);
+
+        if (c->vtable[0].flags & SD_BUS_VTABLE_HIDDEN)
+                return 1;
+
+        v = c->vtable;
+        for (v = bus_vtable_next(c->vtable, v); v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(c->vtable, v)) {
+                if (!IN_SET(v->type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY))
+                        continue;
+
+                if (v->flags & SD_BUS_VTABLE_HIDDEN)
+                        continue;
+
+                /* Let's not include properties marked as "explicit" in any message that contains a generic
+                 * dump of properties, but only in those generated as a response to an explicit request. */
+                if (v->flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
+                        continue;
+
+                /* Let's not include properties marked only for invalidation on change (i.e. in contrast to
+                 * those whose new values are included in PropertiesChanges message) in any signals. This is
+                 * useful to ensure they aren't included in InterfacesAdded messages. */
+                if (reply->header->type != SD_BUS_MESSAGE_METHOD_RETURN &&
+                    FLAGS_SET(v->flags, SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION))
+                        continue;
+
+                r = vtable_append_one_property(bus, reply, path, c, v, userdata, error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        return 1;
+}
+
+static int property_get_all_callbacks_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node_vtable *first,
+                bool require_fallback,
+                const char *iface,
+                bool *found_object) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        struct node_vtable *c;
+        bool found_interface;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(found_object);
+
+        r = sd_bus_message_new_method_return(m, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'a', "{sv}");
+        if (r < 0)
+                return r;
+
+        found_interface = !iface || STR_IN_SET(iface,
+                                               "org.freedesktop.DBus.Properties",
+                                               "org.freedesktop.DBus.Peer",
+                                               "org.freedesktop.DBus.Introspectable");
+
+        LIST_FOREACH(vtables, c, first) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                void *u;
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                r = node_vtable_get_userdata(bus, m->path, c, &u, &error);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, &error);
+                if (bus->nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                *found_object = true;
+
+                if (iface && !streq(c->interface, iface))
+                        continue;
+                found_interface = true;
+
+                r = vtable_append_all_properties(bus, reply, m->path, c, u, &error);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, &error);
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        if (!*found_object)
+                return 0;
+
+        if (!found_interface) {
+                r = sd_bus_reply_method_errorf(
+                                m,
+                                SD_BUS_ERROR_UNKNOWN_INTERFACE,
+                                "Unknown interface '%s'.", iface);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int bus_node_exists(
+                sd_bus *bus,
+                struct node *n,
+                const char *path,
+                bool require_fallback) {
+
+        struct node_vtable *c;
+        struct node_callback *k;
+        int r;
+
+        assert(bus);
+        assert(n);
+        assert(path);
+
+        /* Tests if there's anything attached directly to this node
+         * for the specified path */
+
+        if (!require_fallback && (n->enumerators || n->object_managers))
+                return true;
+
+        LIST_FOREACH(callbacks, k, n->callbacks) {
+                if (require_fallback && !k->is_fallback)
+                        continue;
+
+                return 1;
+        }
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, c, NULL, &error);
+                if (r != 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        return 0;
+}
+
+int introspect_path(
+                sd_bus *bus,
+                const char *path,
+                struct node *n,
+                bool require_fallback,
+                bool ignore_nodes_modified,
+                bool *found_object,
+                char **ret,
+                sd_bus_error *error) {
+
+        _cleanup_set_free_free_ Set *s = NULL;
+        _cleanup_(introspect_free) struct introspect intro = {};
+        struct node_vtable *c;
+        bool empty;
+        int r;
+
+        if (!n) {
+                n = hashmap_get(bus->nodes, path);
+                if (!n)
+                        return -ENOENT;
+        }
+
+        r = get_child_nodes(bus, path, n, 0, &s, error);
+        if (r < 0)
+                return r;
+        if (bus->nodes_modified && !ignore_nodes_modified)
+                return 0;
+
+        r = introspect_begin(&intro, bus->trusted);
+        if (r < 0)
+                return r;
+
+        r = introspect_write_default_interfaces(&intro, !require_fallback && n->object_managers);
+        if (r < 0)
+                return r;
+
+        empty = set_isempty(s);
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, c, NULL, error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified && !ignore_nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                empty = false;
+
+                if (c->vtable[0].flags & SD_BUS_VTABLE_HIDDEN)
+                        continue;
+
+                r = introspect_write_interface(&intro, c->interface, c->vtable);
+                if (r < 0)
+                        return r;
+        }
+
+        if (empty) {
+                /* Nothing?, let's see if we exist at all, and if not
+                 * refuse to do anything */
+                r = bus_node_exists(bus, n, path, require_fallback);
+                if (r <= 0)
+                        return r;
+                if (bus->nodes_modified && !ignore_nodes_modified)
+                        return 0;
+        }
+
+        if (found_object)
+                *found_object = true;
+
+        r = introspect_write_child_nodes(&intro, s, path);
+        if (r < 0)
+                return r;
+
+        r = introspect_finish(&intro, ret);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int process_introspect(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node *n,
+                bool require_fallback,
+                bool *found_object) {
+
+        _cleanup_free_ char *s = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(n);
+        assert(found_object);
+
+        r = introspect_path(bus, m->path, n, require_fallback, false, found_object, &s, &error);
+        if (r < 0)
+                return bus_maybe_reply_error(m, r, &error);
+        if (r == 0)
+                /* nodes_modified == true */
+                return 0;
+
+        r = sd_bus_message_new_method_return(m, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(reply, "s", s);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int object_manager_serialize_path(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *prefix,
+                const char *path,
+                bool require_fallback,
+                sd_bus_error *error) {
+
+        const char *previous_interface = NULL;
+        bool found_something = false;
+        struct node_vtable *i;
+        struct node *n;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(prefix);
+        assert(path);
+        assert(error);
+
+        n = hashmap_get(bus->nodes, prefix);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(vtables, i, n->vtables) {
+                void *u;
+
+                if (require_fallback && !i->is_fallback)
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, i, &u, error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                if (!found_something) {
+
+                        /* Open the object part */
+
+                        r = sd_bus_message_open_container(reply, 'e', "oa{sa{sv}}");
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_append(reply, "o", path);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_open_container(reply, 'a', "{sa{sv}}");
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_append(reply, "{sa{sv}}", "org.freedesktop.DBus.Peer", 0);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_append(reply, "{sa{sv}}", "org.freedesktop.DBus.Introspectable", 0);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_append(reply, "{sa{sv}}", "org.freedesktop.DBus.Properties", 0);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_append(reply, "{sa{sv}}", "org.freedesktop.DBus.ObjectManager", 0);
+                        if (r < 0)
+                                return r;
+
+                        found_something = true;
+                }
+
+                if (!streq_ptr(previous_interface, i->interface)) {
+
+                        /* Maybe close the previous interface part */
+
+                        if (previous_interface) {
+                                r = sd_bus_message_close_container(reply);
+                                if (r < 0)
+                                        return r;
+
+                                r = sd_bus_message_close_container(reply);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        /* Open the new interface part */
+
+                        r = sd_bus_message_open_container(reply, 'e', "sa{sv}");
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_append(reply, "s", i->interface);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_open_container(reply, 'a', "{sv}");
+                        if (r < 0)
+                                return r;
+                }
+
+                r = vtable_append_all_properties(bus, reply, path, i, u, error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+
+                previous_interface = i->interface;
+        }
+
+        if (previous_interface) {
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+        }
+
+        if (found_something) {
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_close_container(reply);
+                if (r < 0)
+                        return r;
+        }
+
+        return 1;
+}
+
+static int object_manager_serialize_path_and_fallbacks(
+                sd_bus *bus,
+                sd_bus_message *reply,
+                const char *path,
+                sd_bus_error *error) {
+
+        _cleanup_free_ char *prefix = NULL;
+        size_t pl;
+        int r;
+
+        assert(bus);
+        assert(reply);
+        assert(path);
+        assert(error);
+
+        /* First, add all vtables registered for this path */
+        r = object_manager_serialize_path(bus, reply, path, path, false, error);
+        if (r < 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        /* Second, add fallback vtables registered for any of the prefixes */
+        pl = strlen(path);
+        assert(pl <= BUS_PATH_SIZE_MAX);
+        prefix = new(char, pl + 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+                r = object_manager_serialize_path(bus, reply, prefix, path, true, error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        return 0;
+}
+
+static int process_get_managed_objects(
+                sd_bus *bus,
+                sd_bus_message *m,
+                struct node *n,
+                bool require_fallback,
+                bool *found_object) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_set_free_free_ Set *s = NULL;
+        char *path;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(n);
+        assert(found_object);
+
+        /* Spec says, GetManagedObjects() is only implemented on the root of a
+         * sub-tree. Therefore, we require a registered object-manager on
+         * exactly the queried path, otherwise, we refuse to respond. */
+
+        if (require_fallback || !n->object_managers)
+                return 0;
+
+        r = get_child_nodes(bus, m->path, n, CHILDREN_RECURSIVE, &s, &error);
+        if (r < 0)
+                return bus_maybe_reply_error(m, r, &error);
+        if (bus->nodes_modified)
+                return 0;
+
+        r = sd_bus_message_new_method_return(m, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(reply, 'a', "{oa{sa{sv}}}");
+        if (r < 0)
+                return r;
+
+        SET_FOREACH(path, s) {
+                r = object_manager_serialize_path_and_fallbacks(bus, reply, path, &error);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, &error);
+
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        r = sd_bus_message_close_container(reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int object_find_and_run(
+                sd_bus *bus,
+                sd_bus_message *m,
+                const char *p,
+                bool require_fallback,
+                bool *found_object) {
+
+        struct node *n;
+        struct vtable_member vtable_key, *v;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(p);
+        assert(found_object);
+
+        n = hashmap_get(bus->nodes, p);
+        if (!n)
+                return 0;
+
+        /* First, try object callbacks */
+        r = node_callbacks_run(bus, m, n->callbacks, require_fallback, found_object);
+        if (r != 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        if (!m->interface || !m->member)
+                return 0;
+
+        /* Then, look for a known method */
+        vtable_key.path = (char*) p;
+        vtable_key.interface = m->interface;
+        vtable_key.member = m->member;
+
+        v = hashmap_get(bus->vtable_methods, &vtable_key);
+        if (v) {
+                r = method_callbacks_run(bus, m, v, require_fallback, found_object);
+                if (r != 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        /* Then, look for a known property */
+        if (streq(m->interface, "org.freedesktop.DBus.Properties")) {
+                bool get = false;
+
+                get = streq(m->member, "Get");
+
+                if (get || streq(m->member, "Set")) {
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        vtable_key.path = (char*) p;
+
+                        r = sd_bus_message_read(m, "ss", &vtable_key.interface, &vtable_key.member);
+                        if (r < 0)
+                                return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INVALID_ARGS, "Expected interface and member parameters");
+
+                        v = hashmap_get(bus->vtable_properties, &vtable_key);
+                        if (v) {
+                                r = property_get_set_callbacks_run(bus, m, v, require_fallback, get, found_object);
+                                if (r != 0)
+                                        return r;
+                        }
+
+                } else if (streq(m->member, "GetAll")) {
+                        const char *iface;
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_read(m, "s", &iface);
+                        if (r < 0)
+                                return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INVALID_ARGS, "Expected interface parameter");
+
+                        if (iface[0] == 0)
+                                iface = NULL;
+
+                        r = property_get_all_callbacks_run(bus, m, n->vtables, require_fallback, iface, found_object);
+                        if (r != 0)
+                                return r;
+                }
+
+        } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Introspectable", "Introspect")) {
+
+                if (!isempty(sd_bus_message_get_signature(m, true)))
+                        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INVALID_ARGS, "Expected no parameters");
+
+                r = process_introspect(bus, m, n, require_fallback, found_object);
+                if (r != 0)
+                        return r;
+
+        } else if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus.ObjectManager", "GetManagedObjects")) {
+
+                if (!isempty(sd_bus_message_get_signature(m, true)))
+                        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INVALID_ARGS, "Expected no parameters");
+
+                r = process_get_managed_objects(bus, m, n, require_fallback, found_object);
+                if (r != 0)
+                        return r;
+        }
+
+        if (bus->nodes_modified)
+                return 0;
+
+        if (!*found_object) {
+                r = bus_node_exists(bus, n, m->path, require_fallback);
+                if (r < 0)
+                        return bus_maybe_reply_error(m, r, NULL);
+                if (bus->nodes_modified)
+                        return 0;
+                if (r > 0)
+                        *found_object = true;
+        }
+
+        return 0;
+}
+
+int bus_process_object(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_free_ char *prefix = NULL;
+        int r;
+        size_t pl;
+        bool found_object = false;
+
+        assert(bus);
+        assert(m);
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 0;
+
+        if (hashmap_isempty(bus->nodes))
+                return 0;
+
+        /* Never respond to broadcast messages */
+        if (bus->bus_client && !m->destination)
+                return 0;
+
+        assert(m->path);
+        assert(m->member);
+
+        pl = strlen(m->path);
+        assert(pl <= BUS_PATH_SIZE_MAX);
+        prefix = new(char, pl + 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        do {
+                bus->nodes_modified = false;
+
+                r = object_find_and_run(bus, m, m->path, false, &found_object);
+                if (r != 0)
+                        return r;
+
+                /* Look for fallback prefixes */
+                OBJECT_PATH_FOREACH_PREFIX(prefix, m->path) {
+
+                        if (bus->nodes_modified)
+                                break;
+
+                        r = object_find_and_run(bus, m, prefix, true, &found_object);
+                        if (r != 0)
+                                return r;
+                }
+
+        } while (bus->nodes_modified);
+
+        if (!found_object)
+                return 0;
+
+        if (sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Properties", "Get") ||
+            sd_bus_message_is_method_call(m, "org.freedesktop.DBus.Properties", "Set")) {
+                const char *interface = NULL, *property = NULL;
+
+                (void) sd_bus_message_rewind(m, true);
+                (void) sd_bus_message_read_basic(m, 's', &interface);
+                (void) sd_bus_message_read_basic(m, 's', &property);
+
+                r = sd_bus_reply_method_errorf(
+                                m,
+                                SD_BUS_ERROR_UNKNOWN_PROPERTY,
+                                "Unknown interface %s or property %s.", strnull(interface), strnull(property));
+        } else
+                r = sd_bus_reply_method_errorf(
+                                m,
+                                SD_BUS_ERROR_UNKNOWN_METHOD,
+                                "Unknown method %s or interface %s.", m->member, m->interface);
+
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static struct node *bus_node_allocate(sd_bus *bus, const char *path) {
+        struct node *n, *parent;
+        const char *e;
+        _cleanup_free_ char *s = NULL;
+        char *p;
+        int r;
+
+        assert(bus);
+        assert(path);
+        assert(path[0] == '/');
+
+        n = hashmap_get(bus->nodes, path);
+        if (n)
+                return n;
+
+        r = hashmap_ensure_allocated(&bus->nodes, &string_hash_ops);
+        if (r < 0)
+                return NULL;
+
+        s = strdup(path);
+        if (!s)
+                return NULL;
+
+        if (streq(path, "/"))
+                parent = NULL;
+        else {
+                e = strrchr(path, '/');
+                assert(e);
+
+                p = strndupa(path, MAX(1, e - path));
+
+                parent = bus_node_allocate(bus, p);
+                if (!parent)
+                        return NULL;
+        }
+
+        n = new0(struct node, 1);
+        if (!n)
+                return NULL;
+
+        n->parent = parent;
+        n->path = TAKE_PTR(s);
+
+        r = hashmap_put(bus->nodes, n->path, n);
+        if (r < 0) {
+                free(n->path);
+                return mfree(n);
+        }
+
+        if (parent)
+                LIST_PREPEND(siblings, parent->child, n);
+
+        return n;
+}
+
+void bus_node_gc(sd_bus *b, struct node *n) {
+        assert(b);
+
+        if (!n)
+                return;
+
+        if (n->child ||
+            n->callbacks ||
+            n->vtables ||
+            n->enumerators ||
+            n->object_managers)
+                return;
+
+        assert_se(hashmap_remove(b->nodes, n->path) == n);
+
+        if (n->parent)
+                LIST_REMOVE(siblings, n->parent->child, n);
+
+        free(n->path);
+        bus_node_gc(b, n->parent);
+        free(n);
+}
+
+static int bus_find_parent_object_manager(sd_bus *bus, struct node **out, const char *path) {
+        struct node *n;
+
+        assert(bus);
+        assert(path);
+
+        n = hashmap_get(bus->nodes, path);
+        if (!n) {
+                _cleanup_free_ char *prefix = NULL;
+                size_t pl;
+
+                pl = strlen(path);
+                assert(pl <= BUS_PATH_SIZE_MAX);
+                prefix = new(char, pl + 1);
+                if (!prefix)
+                        return -ENOMEM;
+
+                OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+                        n = hashmap_get(bus->nodes, prefix);
+                        if (n)
+                                break;
+                }
+        }
+
+        while (n && !n->object_managers)
+                n = n->parent;
+
+        if (out)
+                *out = n;
+        return !!n;
+}
+
+static int bus_add_object(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                bool fallback,
+                const char *path,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        sd_bus_slot *s;
+        struct node *n;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        s = bus_slot_allocate(bus, !slot, BUS_NODE_CALLBACK, sizeof(struct node_callback), userdata);
+        if (!s) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        s->node_callback.callback = callback;
+        s->node_callback.is_fallback = fallback;
+
+        s->node_callback.node = n;
+        LIST_PREPEND(callbacks, n->callbacks, &s->node_callback);
+        bus->nodes_modified = true;
+
+        if (slot)
+                *slot = s;
+
+        return 0;
+
+fail:
+        sd_bus_slot_unref(s);
+        bus_node_gc(bus, n);
+
+        return r;
+}
+
+_public_ int sd_bus_add_object(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *path,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        return bus_add_object(bus, slot, false, path, callback, userdata);
+}
+
+_public_ int sd_bus_add_fallback(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *prefix,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        return bus_add_object(bus, slot, true, prefix, callback, userdata);
+}
+
+static void vtable_member_hash_func(const struct vtable_member *m, struct siphash *state) {
+        assert(m);
+
+        string_hash_func(m->path, state);
+        string_hash_func(m->interface, state);
+        string_hash_func(m->member, state);
+}
+
+static int vtable_member_compare_func(const struct vtable_member *x, const struct vtable_member *y) {
+        int r;
+
+        assert(x);
+        assert(y);
+
+        r = strcmp(x->path, y->path);
+        if (r != 0)
+                return r;
+
+        r = strcmp(x->interface, y->interface);
+        if (r != 0)
+                return r;
+
+        return strcmp(x->member, y->member);
+}
+
+DEFINE_PRIVATE_HASH_OPS(vtable_member_hash_ops, struct vtable_member, vtable_member_hash_func, vtable_member_compare_func);
+
+typedef enum {
+        NAMES_FIRST_PART        = 1 << 0, /* first part of argument name list (input names). It is reset by names_are_valid() */
+        NAMES_PRESENT           = 1 << 1, /* at least one argument name is present, so the names will checked.
+                                             This flag is set and used internally by names_are_valid(), but needs to be stored across calls for 2-parts list  */
+        NAMES_SINGLE_PART       = 1 << 2, /* argument name list consisting of a single part */
+} names_flags;
+
+static bool names_are_valid(const char *signature, const char **names, names_flags *flags) {
+        int r;
+
+        if ((*flags & NAMES_FIRST_PART || *flags & NAMES_SINGLE_PART) && **names != '\0')
+                *flags |= NAMES_PRESENT;
+
+        for (;*flags & NAMES_PRESENT;) {
+                size_t l;
+
+                if (!*signature)
+                        break;
+
+                r = signature_element_length(signature, &l);
+                if (r < 0)
+                        return false;
+
+                if (**names != '\0') {
+                        if (!member_name_is_valid(*names))
+                                return false;
+                        *names += strlen(*names) + 1;
+                } else if (*flags & NAMES_PRESENT)
+                        return false;
+
+                signature += l;
+        }
+        /* let's check if there are more argument names specified than the signature allows */
+        if (*flags & NAMES_PRESENT && **names != '\0' && !(*flags & NAMES_FIRST_PART))
+                return false;
+        *flags &= ~NAMES_FIRST_PART;
+        return true;
+}
+
+/* the current version of this struct is defined in sd-bus-vtable.h, but we need to list here the historical versions
+   to make sure the calling code is compatible with one of these */
+struct sd_bus_vtable_221 {
+        uint8_t type:8;
+        uint64_t flags:56;
+        union {
+                struct {
+                        size_t element_size;
+                } start;
+                struct {
+                        const char *member;
+                        const char *signature;
+                        const char *result;
+                        sd_bus_message_handler_t handler;
+                        size_t offset;
+                } method;
+                struct {
+                        const char *member;
+                        const char *signature;
+                } signal;
+                struct {
+                        const char *member;
+                        const char *signature;
+                        sd_bus_property_get_t get;
+                        sd_bus_property_set_t set;
+                        size_t offset;
+                } property;
+        } x;
+};
+/* Structure size up to v241 */
+#define VTABLE_ELEMENT_SIZE_221 sizeof(struct sd_bus_vtable_221)
+
+/* Size of the structure when "features" field was added. If the structure definition is augmented, a copy of
+ * the structure definition will need to be made (similarly to the sd_bus_vtable_221 above), and this
+ * definition updated to refer to it. */
+#define VTABLE_ELEMENT_SIZE_242 sizeof(struct sd_bus_vtable)
+
+static int vtable_features(const sd_bus_vtable *vtable) {
+        if (vtable[0].x.start.element_size < VTABLE_ELEMENT_SIZE_242 ||
+            !vtable[0].x.start.vtable_format_reference)
+                return 0;
+        return vtable[0].x.start.features;
+}
+
+bool bus_vtable_has_names(const sd_bus_vtable *vtable) {
+        return vtable_features(vtable) & _SD_BUS_VTABLE_PARAM_NAMES;
+}
+
+const sd_bus_vtable* bus_vtable_next(const sd_bus_vtable *vtable, const sd_bus_vtable *v) {
+        return (const sd_bus_vtable*) ((char*) v + vtable[0].x.start.element_size);
+}
+
+static int add_object_vtable_internal(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *path,
+                const char *interface,
+                const sd_bus_vtable *vtable,
+                bool fallback,
+                sd_bus_object_find_t find,
+                void *userdata) {
+
+        sd_bus_slot *s = NULL;
+        struct node_vtable *i, *existing = NULL;
+        const sd_bus_vtable *v;
+        struct node *n;
+        int r;
+        const char *names = "";
+        names_flags nf;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(interface_name_is_valid(interface), -EINVAL);
+        assert_return(vtable, -EINVAL);
+        assert_return(vtable[0].type == _SD_BUS_VTABLE_START, -EINVAL);
+        assert_return(vtable[0].x.start.element_size == VTABLE_ELEMENT_SIZE_221 ||
+                      vtable[0].x.start.element_size >= VTABLE_ELEMENT_SIZE_242,
+                      -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(!streq(interface, "org.freedesktop.DBus.Properties") &&
+                      !streq(interface, "org.freedesktop.DBus.Introspectable") &&
+                      !streq(interface, "org.freedesktop.DBus.Peer") &&
+                      !streq(interface, "org.freedesktop.DBus.ObjectManager"), -EINVAL);
+
+        r = hashmap_ensure_allocated(&bus->vtable_methods, &vtable_member_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = hashmap_ensure_allocated(&bus->vtable_properties, &vtable_member_hash_ops);
+        if (r < 0)
+                return r;
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        LIST_FOREACH(vtables, i, n->vtables) {
+                if (i->is_fallback != fallback) {
+                        r = -EPROTOTYPE;
+                        goto fail;
+                }
+
+                if (streq(i->interface, interface)) {
+
+                        if (i->vtable == vtable) {
+                                r = -EEXIST;
+                                goto fail;
+                        }
+
+                        existing = i;
+                }
+        }
+
+        s = bus_slot_allocate(bus, !slot, BUS_NODE_VTABLE, sizeof(struct node_vtable), userdata);
+        if (!s) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        s->node_vtable.is_fallback = fallback;
+        s->node_vtable.vtable = vtable;
+        s->node_vtable.find = find;
+
+        s->node_vtable.interface = strdup(interface);
+        if (!s->node_vtable.interface) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        v = s->node_vtable.vtable;
+        for (v = bus_vtable_next(vtable, v); v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(vtable, v)) {
+
+                switch (v->type) {
+
+                case _SD_BUS_VTABLE_METHOD: {
+                        struct vtable_member *m;
+                        nf = NAMES_FIRST_PART;
+
+                        if (bus_vtable_has_names(vtable))
+                                names = strempty(v->x.method.names);
+
+                        if (!member_name_is_valid(v->x.method.member) ||
+                            !signature_is_valid(strempty(v->x.method.signature), false) ||
+                            !signature_is_valid(strempty(v->x.method.result), false) ||
+                            !names_are_valid(strempty(v->x.method.signature), &names, &nf) ||
+                            !names_are_valid(strempty(v->x.method.result), &names, &nf) ||
+                            !(v->x.method.handler || (isempty(v->x.method.signature) && isempty(v->x.method.result))) ||
+                            v->flags & (SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE|SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        m = new0(struct vtable_member, 1);
+                        if (!m) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        m->parent = &s->node_vtable;
+                        m->path = n->path;
+                        m->interface = s->node_vtable.interface;
+                        m->member = v->x.method.member;
+                        m->vtable = v;
+
+                        r = hashmap_put(bus->vtable_methods, m, m);
+                        if (r < 0) {
+                                free(m);
+                                goto fail;
+                        }
+
+                        break;
+                }
+
+                case _SD_BUS_VTABLE_WRITABLE_PROPERTY:
+
+                        if (!(v->x.property.set || bus_type_is_basic(v->x.property.signature[0]))) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        if (v->flags & SD_BUS_VTABLE_PROPERTY_CONST) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        _fallthrough_;
+                case _SD_BUS_VTABLE_PROPERTY: {
+                        struct vtable_member *m;
+
+                        if (!member_name_is_valid(v->x.property.member) ||
+                            !signature_is_single(v->x.property.signature, false) ||
+                            !(v->x.property.get || bus_type_is_basic(v->x.property.signature[0]) || streq(v->x.property.signature, "as")) ||
+                            (v->flags & SD_BUS_VTABLE_METHOD_NO_REPLY) ||
+                            (!!(v->flags & SD_BUS_VTABLE_PROPERTY_CONST) + !!(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE) + !!(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)) > 1 ||
+                            ((v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE) && (v->flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)) ||
+                            (v->flags & SD_BUS_VTABLE_UNPRIVILEGED && v->type == _SD_BUS_VTABLE_PROPERTY)) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        m = new0(struct vtable_member, 1);
+                        if (!m) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        m->parent = &s->node_vtable;
+                        m->path = n->path;
+                        m->interface = s->node_vtable.interface;
+                        m->member = v->x.property.member;
+                        m->vtable = v;
+
+                        r = hashmap_put(bus->vtable_properties, m, m);
+                        if (r < 0) {
+                                free(m);
+                                goto fail;
+                        }
+
+                        break;
+                }
+
+                case _SD_BUS_VTABLE_SIGNAL:
+                        nf = NAMES_SINGLE_PART;
+
+                        if (bus_vtable_has_names(vtable))
+                                names = strempty(v->x.signal.names);
+
+                        if (!member_name_is_valid(v->x.signal.member) ||
+                            !signature_is_valid(strempty(v->x.signal.signature), false) ||
+                            !names_are_valid(strempty(v->x.signal.signature), &names, &nf) ||
+                            v->flags & SD_BUS_VTABLE_UNPRIVILEGED) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        break;
+
+                default:
+                        r = -EINVAL;
+                        goto fail;
+                }
+        }
+
+        s->node_vtable.node = n;
+        LIST_INSERT_AFTER(vtables, n->vtables, existing, &s->node_vtable);
+        bus->nodes_modified = true;
+
+        if (slot)
+                *slot = s;
+
+        return 0;
+
+fail:
+        sd_bus_slot_unref(s);
+        bus_node_gc(bus, n);
+
+        return r;
+}
+
+/* This symbol exists solely to tell the linker that the "new" vtable format is used. */
+_public_ const unsigned sd_bus_object_vtable_format = 242;
+
+_public_ int sd_bus_add_object_vtable(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *path,
+                const char *interface,
+                const sd_bus_vtable *vtable,
+                void *userdata) {
+
+        return add_object_vtable_internal(bus, slot, path, interface, vtable, false, NULL, userdata);
+}
+
+_public_ int sd_bus_add_fallback_vtable(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *prefix,
+                const char *interface,
+                const sd_bus_vtable *vtable,
+                sd_bus_object_find_t find,
+                void *userdata) {
+
+        return add_object_vtable_internal(bus, slot, prefix, interface, vtable, true, find, userdata);
+}
+
+_public_ int sd_bus_add_node_enumerator(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *path,
+                sd_bus_node_enumerator_t callback,
+                void *userdata) {
+
+        sd_bus_slot *s;
+        struct node *n;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        s = bus_slot_allocate(bus, !slot, BUS_NODE_ENUMERATOR, sizeof(struct node_enumerator), userdata);
+        if (!s) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        s->node_enumerator.callback = callback;
+
+        s->node_enumerator.node = n;
+        LIST_PREPEND(enumerators, n->enumerators, &s->node_enumerator);
+        bus->nodes_modified = true;
+
+        if (slot)
+                *slot = s;
+
+        return 0;
+
+fail:
+        sd_bus_slot_unref(s);
+        bus_node_gc(bus, n);
+
+        return r;
+}
+
+static int emit_properties_changed_on_interface(
+                sd_bus *bus,
+                const char *prefix,
+                const char *path,
+                const char *interface,
+                bool require_fallback,
+                bool *found_interface,
+                char **names) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        bool has_invalidating = false, has_changing = false;
+        struct vtable_member key = {};
+        struct node_vtable *c;
+        struct node *n;
+        char **property;
+        void *u = NULL;
+        int r;
+
+        assert(bus);
+        assert(prefix);
+        assert(path);
+        assert(interface);
+        assert(found_interface);
+
+        n = hashmap_get(bus->nodes, prefix);
+        if (!n)
+                return 0;
+
+        r = sd_bus_message_new_signal(bus, &m, path, "org.freedesktop.DBus.Properties", "PropertiesChanged");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "s", interface);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(m, 'a', "{sv}");
+        if (r < 0)
+                return r;
+
+        key.path = prefix;
+        key.interface = interface;
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                if (!streq(c->interface, interface))
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, c, &u, &error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                *found_interface = true;
+
+                if (names) {
+                        /* If the caller specified a list of
+                         * properties we include exactly those in the
+                         * PropertiesChanged message */
+
+                        STRV_FOREACH(property, names) {
+                                struct vtable_member *v;
+
+                                assert_return(member_name_is_valid(*property), -EINVAL);
+
+                                key.member = *property;
+                                v = hashmap_get(bus->vtable_properties, &key);
+                                if (!v)
+                                        return -ENOENT;
+
+                                /* If there are two vtables for the same
+                                 * interface, let's handle this property when
+                                 * we come to that vtable. */
+                                if (c != v->parent)
+                                        continue;
+
+                                assert_return(v->vtable->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE ||
+                                              v->vtable->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION, -EDOM);
+
+                                assert_return(!(v->vtable->flags & SD_BUS_VTABLE_HIDDEN), -EDOM);
+
+                                if (v->vtable->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION) {
+                                        has_invalidating = true;
+                                        continue;
+                                }
+
+                                has_changing = true;
+
+                                r = vtable_append_one_property(bus, m, m->path, c, v->vtable, u, &error);
+                                if (r < 0)
+                                        return r;
+                                if (bus->nodes_modified)
+                                        return 0;
+                        }
+                } else {
+                        const sd_bus_vtable *v;
+
+                        /* If the caller specified no properties list
+                         * we include all properties that are marked
+                         * as changing in the message. */
+
+                        v = c->vtable;
+                        for (v = bus_vtable_next(c->vtable, v); v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(c->vtable, v)) {
+                                if (!IN_SET(v->type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY))
+                                        continue;
+
+                                if (v->flags & SD_BUS_VTABLE_HIDDEN)
+                                        continue;
+
+                                if (v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION) {
+                                        has_invalidating = true;
+                                        continue;
+                                }
+
+                                if (!(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
+                                        continue;
+
+                                has_changing = true;
+
+                                r = vtable_append_one_property(bus, m, m->path, c, v, u, &error);
+                                if (r < 0)
+                                        return r;
+                                if (bus->nodes_modified)
+                                        return 0;
+                        }
+                }
+        }
+
+        if (!has_invalidating && !has_changing)
+                return 0;
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(m, 'a', "s");
+        if (r < 0)
+                return r;
+
+        if (has_invalidating) {
+                LIST_FOREACH(vtables, c, n->vtables) {
+                        if (require_fallback && !c->is_fallback)
+                                continue;
+
+                        if (!streq(c->interface, interface))
+                                continue;
+
+                        r = node_vtable_get_userdata(bus, path, c, &u, &error);
+                        if (r < 0)
+                                return r;
+                        if (bus->nodes_modified)
+                                return 0;
+                        if (r == 0)
+                                continue;
+
+                        if (names) {
+                                STRV_FOREACH(property, names) {
+                                        struct vtable_member *v;
+
+                                        key.member = *property;
+                                        assert_se(v = hashmap_get(bus->vtable_properties, &key));
+                                        assert(c == v->parent);
+
+                                        if (!(v->vtable->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION))
+                                                continue;
+
+                                        r = sd_bus_message_append(m, "s", *property);
+                                        if (r < 0)
+                                                return r;
+                                }
+                        } else {
+                                const sd_bus_vtable *v;
+
+                                v = c->vtable;
+                                for (v = bus_vtable_next(c->vtable, v); v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(c->vtable, v)) {
+                                        if (!IN_SET(v->type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY))
+                                                continue;
+
+                                        if (v->flags & SD_BUS_VTABLE_HIDDEN)
+                                                continue;
+
+                                        if (!(v->flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION))
+                                                continue;
+
+                                        r = sd_bus_message_append(m, "s", v->x.property.member);
+                                        if (r < 0)
+                                                return r;
+                                }
+                        }
+                }
+        }
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, m, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+_public_ int sd_bus_emit_properties_changed_strv(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                char **names) {
+
+        _cleanup_free_ char *prefix = NULL;
+        bool found_interface = false;
+        size_t pl;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(interface_name_is_valid(interface), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* A non-NULL but empty names list means nothing needs to be
+           generated. A NULL list OTOH indicates that all properties
+           that are set to EMITS_CHANGE or EMITS_INVALIDATION shall be
+           included in the PropertiesChanged message. */
+        if (names && names[0] == NULL)
+                return 0;
+
+        BUS_DONT_DESTROY(bus);
+
+        pl = strlen(path);
+        assert(pl <= BUS_PATH_SIZE_MAX);
+        prefix = new(char, pl + 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        do {
+                bus->nodes_modified = false;
+
+                r = emit_properties_changed_on_interface(bus, path, path, interface, false, &found_interface, names);
+                if (r != 0)
+                        return r;
+                if (bus->nodes_modified)
+                        continue;
+
+                OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+                        r = emit_properties_changed_on_interface(bus, prefix, path, interface, true, &found_interface, names);
+                        if (r != 0)
+                                return r;
+                        if (bus->nodes_modified)
+                                break;
+                }
+
+        } while (bus->nodes_modified);
+
+        return found_interface ? 0 : -ENOENT;
+}
+
+_public_ int sd_bus_emit_properties_changed(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *name, ...)  {
+
+        char **names;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(interface_name_is_valid(interface), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (!name)
+                return 0;
+
+        names = strv_from_stdarg_alloca(name);
+
+        return sd_bus_emit_properties_changed_strv(bus, path, interface, names);
+}
+
+static int object_added_append_all_prefix(
+                sd_bus *bus,
+                sd_bus_message *m,
+                Set *s,
+                const char *prefix,
+                const char *path,
+                bool require_fallback) {
+
+        const char *previous_interface = NULL;
+        struct node_vtable *c;
+        struct node *n;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(s);
+        assert(prefix);
+        assert(path);
+
+        n = hashmap_get(bus->nodes, prefix);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                void *u = NULL;
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, c, &u, &error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                if (!streq_ptr(c->interface, previous_interface)) {
+                        /* If a child-node already handled this interface, we
+                         * skip it on any of its parents. The child vtables
+                         * always fully override any conflicting vtables of
+                         * any parent node. */
+                        if (set_get(s, c->interface))
+                                continue;
+
+                        r = set_put(s, c->interface);
+                        if (r < 0)
+                                return r;
+
+                        if (previous_interface) {
+                                r = sd_bus_message_close_container(m);
+                                if (r < 0)
+                                        return r;
+                                r = sd_bus_message_close_container(m);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        r = sd_bus_message_open_container(m, 'e', "sa{sv}");
+                        if (r < 0)
+                                return r;
+                        r = sd_bus_message_append(m, "s", c->interface);
+                        if (r < 0)
+                                return r;
+                        r = sd_bus_message_open_container(m, 'a', "{sv}");
+                        if (r < 0)
+                                return r;
+
+                        previous_interface = c->interface;
+                }
+
+                r = vtable_append_all_properties(bus, m, path, c, u, &error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        if (previous_interface) {
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int object_added_append_all(sd_bus *bus, sd_bus_message *m, const char *path) {
+        _cleanup_set_free_ Set *s = NULL;
+        _cleanup_free_ char *prefix = NULL;
+        size_t pl;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(path);
+
+        /*
+         * This appends all interfaces registered on path @path. We first add
+         * the builtin interfaces, which are always available and handled by
+         * sd-bus. Then, we add all interfaces registered on the exact node,
+         * followed by all fallback interfaces registered on any parent prefix.
+         *
+         * If an interface is registered multiple times on the same node with
+         * different vtables, we merge all the properties across all vtables.
+         * However, if a child node has the same interface registered as one of
+         * its parent nodes has as fallback, we make the child overwrite the
+         * parent instead of extending it. Therefore, we keep a "Set" of all
+         * handled interfaces during parent traversal, so we skip interfaces on
+         * a parent that were overwritten by a child.
+         */
+
+        s = set_new(&string_hash_ops);
+        if (!s)
+                return -ENOMEM;
+
+        r = sd_bus_message_append(m, "{sa{sv}}", "org.freedesktop.DBus.Peer", 0);
+        if (r < 0)
+                return r;
+        r = sd_bus_message_append(m, "{sa{sv}}", "org.freedesktop.DBus.Introspectable", 0);
+        if (r < 0)
+                return r;
+        r = sd_bus_message_append(m, "{sa{sv}}", "org.freedesktop.DBus.Properties", 0);
+        if (r < 0)
+                return r;
+        r = sd_bus_message_append(m, "{sa{sv}}", "org.freedesktop.DBus.ObjectManager", 0);
+        if (r < 0)
+                return r;
+
+        r = object_added_append_all_prefix(bus, m, s, path, path, false);
+        if (r < 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        pl = strlen(path);
+        assert(pl <= BUS_PATH_SIZE_MAX);
+        prefix = new(char, pl + 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+                r = object_added_append_all_prefix(bus, m, s, prefix, path, true);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_emit_object_added(sd_bus *bus, const char *path) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct node *object_manager;
+        int r;
+
+        /*
+         * This emits an InterfacesAdded signal on the given path, by iterating
+         * all registered vtables and fallback vtables on the path. All
+         * properties are queried and included in the signal.
+         * This call is equivalent to sd_bus_emit_interfaces_added() with an
+         * explicit list of registered interfaces. However, unlike
+         * interfaces_added(), this call can figure out the list of supported
+         * interfaces itself. Furthermore, it properly adds the builtin
+         * org.freedesktop.DBus.* interfaces.
+         */
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        r = bus_find_parent_object_manager(bus, &object_manager, path);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ESRCH;
+
+        BUS_DONT_DESTROY(bus);
+
+        do {
+                bus->nodes_modified = false;
+                m = sd_bus_message_unref(m);
+
+                r = sd_bus_message_new_signal(bus, &m, object_manager->path, "org.freedesktop.DBus.ObjectManager", "InterfacesAdded");
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append_basic(m, 'o', path);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_open_container(m, 'a', "{sa{sv}}");
+                if (r < 0)
+                        return r;
+
+                r = object_added_append_all(bus, m, path);
+                if (r < 0)
+                        return r;
+
+                if (bus->nodes_modified)
+                        continue;
+
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+
+        } while (bus->nodes_modified);
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+static int object_removed_append_all_prefix(
+                sd_bus *bus,
+                sd_bus_message *m,
+                Set *s,
+                const char *prefix,
+                const char *path,
+                bool require_fallback) {
+
+        const char *previous_interface = NULL;
+        struct node_vtable *c;
+        struct node *n;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(s);
+        assert(prefix);
+        assert(path);
+
+        n = hashmap_get(bus->nodes, prefix);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                void *u = NULL;
+
+                if (require_fallback && !c->is_fallback)
+                        continue;
+                if (streq_ptr(c->interface, previous_interface))
+                        continue;
+
+                /* If a child-node already handled this interface, we
+                 * skip it on any of its parents. The child vtables
+                 * always fully override any conflicting vtables of
+                 * any parent node. */
+                if (set_get(s, c->interface))
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, c, &u, &error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                r = set_put(s, c->interface);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append(m, "s", c->interface);
+                if (r < 0)
+                        return r;
+
+                previous_interface = c->interface;
+        }
+
+        return 0;
+}
+
+static int object_removed_append_all(sd_bus *bus, sd_bus_message *m, const char *path) {
+        _cleanup_set_free_ Set *s = NULL;
+        _cleanup_free_ char *prefix = NULL;
+        size_t pl;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(path);
+
+        /* see sd_bus_emit_object_added() for details */
+
+        s = set_new(&string_hash_ops);
+        if (!s)
+                return -ENOMEM;
+
+        r = sd_bus_message_append(m, "s", "org.freedesktop.DBus.Peer");
+        if (r < 0)
+                return r;
+        r = sd_bus_message_append(m, "s", "org.freedesktop.DBus.Introspectable");
+        if (r < 0)
+                return r;
+        r = sd_bus_message_append(m, "s", "org.freedesktop.DBus.Properties");
+        if (r < 0)
+                return r;
+        r = sd_bus_message_append(m, "s", "org.freedesktop.DBus.ObjectManager");
+        if (r < 0)
+                return r;
+
+        r = object_removed_append_all_prefix(bus, m, s, path, path, false);
+        if (r < 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        pl = strlen(path);
+        assert(pl <= BUS_PATH_SIZE_MAX);
+        prefix = new(char, pl + 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+                r = object_removed_append_all_prefix(bus, m, s, prefix, path, true);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        return 0;
+}
+
+_public_ int sd_bus_emit_object_removed(sd_bus *bus, const char *path) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct node *object_manager;
+        int r;
+
+        /*
+         * This is like sd_bus_emit_object_added(), but emits an
+         * InterfacesRemoved signal on the given path. This only includes any
+         * registered interfaces but skips the properties. Note that this will
+         * call into the find() callbacks of any registered vtable. Therefore,
+         * you must call this function before destroying/unlinking your object.
+         * Otherwise, the list of interfaces will be incomplete. However, note
+         * that this will *NOT* call into any property callback. Therefore, the
+         * object might be in an "destructed" state, as long as we can find it.
+         */
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        r = bus_find_parent_object_manager(bus, &object_manager, path);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ESRCH;
+
+        BUS_DONT_DESTROY(bus);
+
+        do {
+                bus->nodes_modified = false;
+                m = sd_bus_message_unref(m);
+
+                r = sd_bus_message_new_signal(bus, &m, object_manager->path, "org.freedesktop.DBus.ObjectManager", "InterfacesRemoved");
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append_basic(m, 'o', path);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_open_container(m, 'a', "s");
+                if (r < 0)
+                        return r;
+
+                r = object_removed_append_all(bus, m, path);
+                if (r < 0)
+                        return r;
+
+                if (bus->nodes_modified)
+                        continue;
+
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+
+        } while (bus->nodes_modified);
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+static int interfaces_added_append_one_prefix(
+                sd_bus *bus,
+                sd_bus_message *m,
+                const char *prefix,
+                const char *path,
+                const char *interface,
+                bool require_fallback) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        bool found_interface = false;
+        struct node_vtable *c;
+        struct node *n;
+        void *u = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(prefix);
+        assert(path);
+        assert(interface);
+
+        n = hashmap_get(bus->nodes, prefix);
+        if (!n)
+                return 0;
+
+        LIST_FOREACH(vtables, c, n->vtables) {
+                if (require_fallback && !c->is_fallback)
+                        continue;
+
+                if (!streq(c->interface, interface))
+                        continue;
+
+                r = node_vtable_get_userdata(bus, path, c, &u, &error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+                if (r == 0)
+                        continue;
+
+                if (!found_interface) {
+                        r = sd_bus_message_append_basic(m, 's', interface);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_bus_message_open_container(m, 'a', "{sv}");
+                        if (r < 0)
+                                return r;
+
+                        found_interface = true;
+                }
+
+                r = vtable_append_all_properties(bus, m, path, c, u, &error);
+                if (r < 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        if (found_interface) {
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+        }
+
+        return found_interface;
+}
+
+static int interfaces_added_append_one(
+                sd_bus *bus,
+                sd_bus_message *m,
+                const char *path,
+                const char *interface) {
+
+        _cleanup_free_ char *prefix = NULL;
+        size_t pl;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(path);
+        assert(interface);
+
+        r = interfaces_added_append_one_prefix(bus, m, path, path, interface, false);
+        if (r != 0)
+                return r;
+        if (bus->nodes_modified)
+                return 0;
+
+        pl = strlen(path);
+        assert(pl <= BUS_PATH_SIZE_MAX);
+        prefix = new(char, pl + 1);
+        if (!prefix)
+                return -ENOMEM;
+
+        OBJECT_PATH_FOREACH_PREFIX(prefix, path) {
+                r = interfaces_added_append_one_prefix(bus, m, prefix, path, interface, true);
+                if (r != 0)
+                        return r;
+                if (bus->nodes_modified)
+                        return 0;
+        }
+
+        return -ENOENT;
+}
+
+_public_ int sd_bus_emit_interfaces_added_strv(sd_bus *bus, const char *path, char **interfaces) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct node *object_manager;
+        char **i;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (strv_isempty(interfaces))
+                return 0;
+
+        r = bus_find_parent_object_manager(bus, &object_manager, path);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ESRCH;
+
+        BUS_DONT_DESTROY(bus);
+
+        do {
+                bus->nodes_modified = false;
+                m = sd_bus_message_unref(m);
+
+                r = sd_bus_message_new_signal(bus, &m, object_manager->path, "org.freedesktop.DBus.ObjectManager", "InterfacesAdded");
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append_basic(m, 'o', path);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_open_container(m, 'a', "{sa{sv}}");
+                if (r < 0)
+                        return r;
+
+                STRV_FOREACH(i, interfaces) {
+                        assert_return(interface_name_is_valid(*i), -EINVAL);
+
+                        r = sd_bus_message_open_container(m, 'e', "sa{sv}");
+                        if (r < 0)
+                                return r;
+
+                        r = interfaces_added_append_one(bus, m, path, *i);
+                        if (r < 0)
+                                return r;
+
+                        if (bus->nodes_modified)
+                                break;
+
+                        r = sd_bus_message_close_container(m);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (bus->nodes_modified)
+                        continue;
+
+                r = sd_bus_message_close_container(m);
+                if (r < 0)
+                        return r;
+
+        } while (bus->nodes_modified);
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+_public_ int sd_bus_emit_interfaces_added(sd_bus *bus, const char *path, const char *interface, ...) {
+        char **interfaces;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        interfaces = strv_from_stdarg_alloca(interface);
+
+        return sd_bus_emit_interfaces_added_strv(bus, path, interfaces);
+}
+
+_public_ int sd_bus_emit_interfaces_removed_strv(sd_bus *bus, const char *path, char **interfaces) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct node *object_manager;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (strv_isempty(interfaces))
+                return 0;
+
+        r = bus_find_parent_object_manager(bus, &object_manager, path);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ESRCH;
+
+        r = sd_bus_message_new_signal(bus, &m, object_manager->path, "org.freedesktop.DBus.ObjectManager", "InterfacesRemoved");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append_basic(m, 'o', path);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append_strv(m, interfaces);
+        if (r < 0)
+                return r;
+
+        return sd_bus_send(bus, m, NULL);
+}
+
+_public_ int sd_bus_emit_interfaces_removed(sd_bus *bus, const char *path, const char *interface, ...) {
+        char **interfaces;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        interfaces = strv_from_stdarg_alloca(interface);
+
+        return sd_bus_emit_interfaces_removed_strv(bus, path, interfaces);
+}
+
+_public_ int sd_bus_add_object_manager(sd_bus *bus, sd_bus_slot **slot, const char *path) {
+        sd_bus_slot *s;
+        struct node *n;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        n = bus_node_allocate(bus, path);
+        if (!n)
+                return -ENOMEM;
+
+        s = bus_slot_allocate(bus, !slot, BUS_NODE_OBJECT_MANAGER, sizeof(struct node_object_manager), NULL);
+        if (!s) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        s->node_object_manager.node = n;
+        LIST_PREPEND(object_managers, n->object_managers, &s->node_object_manager);
+        bus->nodes_modified = true;
+
+        if (slot)
+                *slot = s;
+
+        return 0;
+
+fail:
+        sd_bus_slot_unref(s);
+        bus_node_gc(bus, n);
+
+        return r;
+}
diff --git a/src/libsystemd/sd-bus/bus-objects.h b/src/libsystemd/sd-bus/bus-objects.h
new file mode 100644
index 0000000..20fccfa
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-objects.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "bus-internal.h"
+#include "bus-introspect.h"
+
+const sd_bus_vtable* bus_vtable_next(const sd_bus_vtable *vtable, const sd_bus_vtable *v);
+bool bus_vtable_has_names(const sd_bus_vtable *vtable);
+int bus_process_object(sd_bus *bus, sd_bus_message *m);
+void bus_node_gc(sd_bus *b, struct node *n);
+
+int introspect_path(
+                sd_bus *bus,
+                const char *path,
+                struct node *n,
+                bool require_fallback,
+                bool ignore_nodes_modified,
+                bool *found_object,
+                char **ret,
+                sd_bus_error *error);
diff --git a/src/libsystemd/sd-bus/bus-protocol.h b/src/libsystemd/sd-bus/bus-protocol.h
new file mode 100644
index 0000000..c41ab58
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-protocol.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <endian.h>
+
+#include "macro.h"
+
+/* Packet header */
+
+struct _packed_ bus_header {
+        /* The first four fields are identical for dbus1, and dbus2 */
+        uint8_t endian;
+        uint8_t type;
+        uint8_t flags;
+        uint8_t version;
+
+        union _packed_ {
+                /* dbus1: Used for SOCK_STREAM connections */
+                struct _packed_ {
+                        uint32_t body_size;
+
+                        /* Note that what the bus spec calls "serial" we'll call
+                           "cookie" instead, because we don't want to imply that the
+                           cookie was in any way monotonically increasing. */
+                        uint32_t serial;
+                        uint32_t fields_size;
+                } dbus1;
+
+                /* dbus2: Used for kdbus connections */
+                struct _packed_ {
+                        uint32_t _reserved;
+                        uint64_t cookie;
+                } dbus2;
+
+                /* Note that both header versions have the same size! */
+        };
+};
+
+/* Endianness */
+
+enum {
+        _BUS_INVALID_ENDIAN = 0,
+        BUS_LITTLE_ENDIAN   = 'l',
+        BUS_BIG_ENDIAN      = 'B',
+#if __BYTE_ORDER == __BIG_ENDIAN
+        BUS_NATIVE_ENDIAN   = BUS_BIG_ENDIAN,
+        BUS_REVERSE_ENDIAN  = BUS_LITTLE_ENDIAN
+#else
+        BUS_NATIVE_ENDIAN   = BUS_LITTLE_ENDIAN,
+        BUS_REVERSE_ENDIAN  = BUS_BIG_ENDIAN
+#endif
+};
+
+/* Flags */
+
+enum {
+        BUS_MESSAGE_NO_REPLY_EXPECTED               = 1 << 0,
+        BUS_MESSAGE_NO_AUTO_START                   = 1 << 1,
+        BUS_MESSAGE_ALLOW_INTERACTIVE_AUTHORIZATION = 1 << 2,
+};
+
+/* Header fields */
+
+enum {
+        _BUS_MESSAGE_HEADER_INVALID = 0,
+        BUS_MESSAGE_HEADER_PATH,
+        BUS_MESSAGE_HEADER_INTERFACE,
+        BUS_MESSAGE_HEADER_MEMBER,
+        BUS_MESSAGE_HEADER_ERROR_NAME,
+        BUS_MESSAGE_HEADER_REPLY_SERIAL,
+        BUS_MESSAGE_HEADER_DESTINATION,
+        BUS_MESSAGE_HEADER_SENDER,
+        BUS_MESSAGE_HEADER_SIGNATURE,
+        BUS_MESSAGE_HEADER_UNIX_FDS,
+        _BUS_MESSAGE_HEADER_MAX
+};
+
+/* RequestName parameters */
+
+enum  {
+        BUS_NAME_ALLOW_REPLACEMENT = 1 << 0,
+        BUS_NAME_REPLACE_EXISTING  = 1 << 1,
+        BUS_NAME_DO_NOT_QUEUE      = 1 << 2,
+};
+
+/* RequestName returns */
+enum  {
+        BUS_NAME_PRIMARY_OWNER = 1,
+        BUS_NAME_IN_QUEUE = 2,
+        BUS_NAME_EXISTS = 3,
+        BUS_NAME_ALREADY_OWNER = 4
+};
+
+/* ReleaseName returns */
+enum {
+        BUS_NAME_RELEASED = 1,
+        BUS_NAME_NON_EXISTENT = 2,
+        BUS_NAME_NOT_OWNER = 3,
+};
+
+/* StartServiceByName returns */
+enum {
+        BUS_START_REPLY_SUCCESS = 1,
+        BUS_START_REPLY_ALREADY_RUNNING = 2,
+};
diff --git a/src/libsystemd/sd-bus/bus-signature.c b/src/libsystemd/sd-bus/bus-signature.c
new file mode 100644
index 0000000..bd0842f
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-signature.c
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <util.h>
+
+#include "sd-bus.h"
+
+#include "bus-signature.h"
+#include "bus-type.h"
+
+static int signature_element_length_internal(
+                const char *s,
+                bool allow_dict_entry,
+                unsigned array_depth,
+                unsigned struct_depth,
+                size_t *l) {
+
+        int r;
+
+        if (!s)
+                return -EINVAL;
+
+        assert(l);
+
+        if (bus_type_is_basic(*s) || *s == SD_BUS_TYPE_VARIANT) {
+                *l = 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_ARRAY) {
+                size_t t;
+
+                if (array_depth >= 32)
+                        return -EINVAL;
+
+                r = signature_element_length_internal(s + 1, true, array_depth+1, struct_depth, &t);
+                if (r < 0)
+                        return r;
+
+                *l = t + 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_STRUCT_BEGIN) {
+                const char *p = s + 1;
+
+                if (struct_depth >= 32)
+                        return -EINVAL;
+
+                while (*p != SD_BUS_TYPE_STRUCT_END) {
+                        size_t t;
+
+                        r = signature_element_length_internal(p, false, array_depth, struct_depth+1, &t);
+                        if (r < 0)
+                                return r;
+
+                        p += t;
+                }
+
+                if (p - s < 2)
+                        /* D-Bus spec: Empty structures are not allowed; there
+                         * must be at least one type code between the parentheses.
+                         */
+                        return -EINVAL;
+
+                *l = p - s + 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_DICT_ENTRY_BEGIN && allow_dict_entry) {
+                const char *p = s + 1;
+                unsigned n = 0;
+
+                if (struct_depth >= 32)
+                        return -EINVAL;
+
+                while (*p != SD_BUS_TYPE_DICT_ENTRY_END) {
+                        size_t t;
+
+                        if (n == 0 && !bus_type_is_basic(*p))
+                                return -EINVAL;
+
+                        r = signature_element_length_internal(p, false, array_depth, struct_depth+1, &t);
+                        if (r < 0)
+                                return r;
+
+                        p += t;
+                        n++;
+                }
+
+                if (n != 2)
+                        return -EINVAL;
+
+                *l = p - s + 1;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+int signature_element_length(const char *s, size_t *l) {
+        return signature_element_length_internal(s, true, 0, 0, l);
+}
+
+bool signature_is_single(const char *s, bool allow_dict_entry) {
+        int r;
+        size_t t;
+
+        if (!s)
+                return false;
+
+        r = signature_element_length_internal(s, allow_dict_entry, 0, 0, &t);
+        if (r < 0)
+                return false;
+
+        return s[t] == 0;
+}
+
+bool signature_is_pair(const char *s) {
+
+        if (!s)
+                return false;
+
+        if (!bus_type_is_basic(*s))
+                return false;
+
+        return signature_is_single(s + 1, false);
+}
+
+bool signature_is_valid(const char *s, bool allow_dict_entry) {
+        const char *p;
+        int r;
+
+        if (!s)
+                return false;
+
+        p = s;
+        while (*p) {
+                size_t t;
+
+                r = signature_element_length_internal(p, allow_dict_entry, 0, 0, &t);
+                if (r < 0)
+                        return false;
+
+                p += t;
+        }
+
+        return p - s <= SD_BUS_MAXIMUM_SIGNATURE_LENGTH;
+}
diff --git a/src/libsystemd/sd-bus/bus-signature.h b/src/libsystemd/sd-bus/bus-signature.h
new file mode 100644
index 0000000..314fcc2
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-signature.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+bool signature_is_single(const char *s, bool allow_dict_entry);
+bool signature_is_pair(const char *s);
+bool signature_is_valid(const char *s, bool allow_dict_entry);
+
+int signature_element_length(const char *s, size_t *l);
diff --git a/src/libsystemd/sd-bus/bus-slot.c b/src/libsystemd/sd-bus/bus-slot.c
new file mode 100644
index 0000000..a0009a7
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-slot.c
@@ -0,0 +1,311 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-control.h"
+#include "bus-objects.h"
+#include "bus-slot.h"
+#include "string-util.h"
+
+sd_bus_slot *bus_slot_allocate(
+                sd_bus *bus,
+                bool floating,
+                BusSlotType type,
+                size_t extra,
+                void *userdata) {
+
+        sd_bus_slot *slot;
+
+        assert(bus);
+
+        slot = malloc0(offsetof(sd_bus_slot, reply_callback) + extra);
+        if (!slot)
+                return NULL;
+
+        slot->n_ref = 1;
+        slot->type = type;
+        slot->bus = bus;
+        slot->floating = floating;
+        slot->userdata = userdata;
+
+        if (!floating)
+                sd_bus_ref(bus);
+
+        LIST_PREPEND(slots, bus->slots, slot);
+
+        return slot;
+}
+
+void bus_slot_disconnect(sd_bus_slot *slot, bool unref) {
+        sd_bus *bus;
+
+        assert(slot);
+
+        if (!slot->bus)
+                return;
+
+        switch (slot->type) {
+
+        case BUS_REPLY_CALLBACK:
+
+                if (slot->reply_callback.cookie != 0)
+                        ordered_hashmap_remove(slot->bus->reply_callbacks, &slot->reply_callback.cookie);
+
+                if (slot->reply_callback.timeout_usec != 0)
+                        prioq_remove(slot->bus->reply_callbacks_prioq, &slot->reply_callback, &slot->reply_callback.prioq_idx);
+
+                break;
+
+        case BUS_FILTER_CALLBACK:
+                slot->bus->filter_callbacks_modified = true;
+                LIST_REMOVE(callbacks, slot->bus->filter_callbacks, &slot->filter_callback);
+                break;
+
+        case BUS_MATCH_CALLBACK:
+
+                if (slot->match_added)
+                        (void) bus_remove_match_internal(slot->bus, slot->match_callback.match_string);
+
+                if (slot->match_callback.install_slot) {
+                        bus_slot_disconnect(slot->match_callback.install_slot, true);
+                        slot->match_callback.install_slot = sd_bus_slot_unref(slot->match_callback.install_slot);
+                }
+
+                slot->bus->match_callbacks_modified = true;
+                bus_match_remove(&slot->bus->match_callbacks, &slot->match_callback);
+
+                slot->match_callback.match_string = mfree(slot->match_callback.match_string);
+
+                break;
+
+        case BUS_NODE_CALLBACK:
+
+                if (slot->node_callback.node) {
+                        LIST_REMOVE(callbacks, slot->node_callback.node->callbacks, &slot->node_callback);
+                        slot->bus->nodes_modified = true;
+
+                        bus_node_gc(slot->bus, slot->node_callback.node);
+                }
+
+                break;
+
+        case BUS_NODE_ENUMERATOR:
+
+                if (slot->node_enumerator.node) {
+                        LIST_REMOVE(enumerators, slot->node_enumerator.node->enumerators, &slot->node_enumerator);
+                        slot->bus->nodes_modified = true;
+
+                        bus_node_gc(slot->bus, slot->node_enumerator.node);
+                }
+
+                break;
+
+        case BUS_NODE_OBJECT_MANAGER:
+
+                if (slot->node_object_manager.node) {
+                        LIST_REMOVE(object_managers, slot->node_object_manager.node->object_managers, &slot->node_object_manager);
+                        slot->bus->nodes_modified = true;
+
+                        bus_node_gc(slot->bus, slot->node_object_manager.node);
+                }
+
+                break;
+
+        case BUS_NODE_VTABLE:
+
+                if (slot->node_vtable.node && slot->node_vtable.interface && slot->node_vtable.vtable) {
+                        const sd_bus_vtable *v;
+
+                        for (v = slot->node_vtable.vtable; v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(slot->node_vtable.vtable, v)) {
+                                struct vtable_member *x = NULL;
+
+                                switch (v->type) {
+
+                                case _SD_BUS_VTABLE_METHOD: {
+                                        struct vtable_member key;
+
+                                        key.path = slot->node_vtable.node->path;
+                                        key.interface = slot->node_vtable.interface;
+                                        key.member = v->x.method.member;
+
+                                        x = hashmap_remove(slot->bus->vtable_methods, &key);
+                                        break;
+                                }
+
+                                case _SD_BUS_VTABLE_PROPERTY:
+                                case _SD_BUS_VTABLE_WRITABLE_PROPERTY: {
+                                        struct vtable_member key;
+
+                                        key.path = slot->node_vtable.node->path;
+                                        key.interface = slot->node_vtable.interface;
+                                        key.member = v->x.method.member;
+
+                                        x = hashmap_remove(slot->bus->vtable_properties, &key);
+                                        break;
+                                }}
+
+                                free(x);
+                        }
+                }
+
+                slot->node_vtable.interface = mfree(slot->node_vtable.interface);
+
+                if (slot->node_vtable.node) {
+                        LIST_REMOVE(vtables, slot->node_vtable.node->vtables, &slot->node_vtable);
+                        slot->bus->nodes_modified = true;
+
+                        bus_node_gc(slot->bus, slot->node_vtable.node);
+                }
+
+                break;
+
+        default:
+                assert_not_reached("Wut? Unknown slot type?");
+        }
+
+        bus = slot->bus;
+
+        slot->type = _BUS_SLOT_INVALID;
+        slot->bus = NULL;
+        LIST_REMOVE(slots, bus->slots, slot);
+
+        if (!slot->floating)
+                sd_bus_unref(bus);
+        else if (unref)
+                sd_bus_slot_unref(slot);
+}
+
+static sd_bus_slot* bus_slot_free(sd_bus_slot *slot) {
+        assert(slot);
+
+        bus_slot_disconnect(slot, false);
+
+        if (slot->destroy_callback)
+                slot->destroy_callback(slot->userdata);
+
+        free(slot->description);
+        return mfree(slot);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_bus_slot, sd_bus_slot, bus_slot_free);
+
+_public_ sd_bus* sd_bus_slot_get_bus(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+
+        return slot->bus;
+}
+
+_public_ void *sd_bus_slot_get_userdata(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+
+        return slot->userdata;
+}
+
+_public_ void *sd_bus_slot_set_userdata(sd_bus_slot *slot, void *userdata) {
+        void *ret;
+
+        assert_return(slot, NULL);
+
+        ret = slot->userdata;
+        slot->userdata = userdata;
+
+        return ret;
+}
+
+_public_ int sd_bus_slot_set_destroy_callback(sd_bus_slot *slot, sd_bus_destroy_t callback) {
+        assert_return(slot, -EINVAL);
+
+        slot->destroy_callback = callback;
+        return 0;
+}
+
+_public_ int sd_bus_slot_get_destroy_callback(sd_bus_slot *slot, sd_bus_destroy_t *callback) {
+        assert_return(slot, -EINVAL);
+
+        if (callback)
+                *callback = slot->destroy_callback;
+
+        return !!slot->destroy_callback;
+}
+
+_public_ sd_bus_message *sd_bus_slot_get_current_message(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+        assert_return(slot->type >= 0, NULL);
+
+        if (slot->bus->current_slot != slot)
+                return NULL;
+
+        return slot->bus->current_message;
+}
+
+_public_ sd_bus_message_handler_t sd_bus_slot_get_current_handler(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+        assert_return(slot->type >= 0, NULL);
+
+        if (slot->bus->current_slot != slot)
+                return NULL;
+
+        return slot->bus->current_handler;
+}
+
+_public_ void* sd_bus_slot_get_current_userdata(sd_bus_slot *slot) {
+        assert_return(slot, NULL);
+        assert_return(slot->type >= 0, NULL);
+
+        if (slot->bus->current_slot != slot)
+                return NULL;
+
+        return slot->bus->current_userdata;
+}
+
+_public_ int sd_bus_slot_get_floating(sd_bus_slot *slot) {
+        assert_return(slot, -EINVAL);
+
+        return slot->floating;
+}
+
+_public_ int sd_bus_slot_set_floating(sd_bus_slot *slot, int b) {
+        assert_return(slot, -EINVAL);
+
+        if (slot->floating == !!b)
+                return 0;
+
+        if (!slot->bus) /* already disconnected slots can't be reconnected */
+                return -ESTALE;
+
+        slot->floating = b;
+
+        /* When a slot is "floating" then the bus references the slot. Otherwise the slot references the bus. Hence,
+         * when we move from one to the other, let's increase one reference and decrease the other. */
+
+        if (b) {
+                sd_bus_slot_ref(slot);
+                sd_bus_unref(slot->bus);
+        } else {
+                sd_bus_ref(slot->bus);
+                sd_bus_slot_unref(slot);
+        }
+
+        return 1;
+}
+
+_public_ int sd_bus_slot_set_description(sd_bus_slot *slot, const char *description) {
+        assert_return(slot, -EINVAL);
+
+        return free_and_strdup(&slot->description, description);
+}
+
+_public_ int sd_bus_slot_get_description(sd_bus_slot *slot, const char **description) {
+        assert_return(slot, -EINVAL);
+        assert_return(description, -EINVAL);
+
+        if (slot->description)
+                *description = slot->description;
+        else if (slot->type == BUS_MATCH_CALLBACK)
+                *description = slot->match_callback.match_string;
+        else
+                return -ENXIO;
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/bus-slot.h b/src/libsystemd/sd-bus/bus-slot.h
new file mode 100644
index 0000000..8116195
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-slot.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+#include "bus-internal.h"
+
+sd_bus_slot *bus_slot_allocate(sd_bus *bus, bool floating, BusSlotType type, size_t extra, void *userdata);
+
+void bus_slot_disconnect(sd_bus_slot *slot, bool unref);
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
new file mode 100644
index 0000000..4881fd0
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -0,0 +1,1348 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <endian.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "sd-bus.h"
+#include "sd-daemon.h"
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-socket.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "hexdecoct.h"
+#include "io-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "rlimit-util.h"
+#include "selinux-util.h"
+#include "signal-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "user-util.h"
+#include "utf8.h"
+
+#define SNDBUF_SIZE (8*1024*1024)
+
+static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) {
+
+        while (size > 0) {
+                struct iovec *i = iov + *idx;
+
+                if (i->iov_len > size) {
+                        i->iov_base = (uint8_t*) i->iov_base + size;
+                        i->iov_len -= size;
+                        return;
+                }
+
+                size -= i->iov_len;
+
+                *i = IOVEC_MAKE(NULL, 0);
+
+                (*idx)++;
+        }
+}
+
+static int append_iovec(sd_bus_message *m, const void *p, size_t sz) {
+        assert(m);
+        assert(p);
+        assert(sz > 0);
+
+        m->iovec[m->n_iovec++] = IOVEC_MAKE((void*) p, sz);
+
+        return 0;
+}
+
+static int bus_message_setup_iovec(sd_bus_message *m) {
+        struct bus_body_part *part;
+        unsigned n, i;
+        int r;
+
+        assert(m);
+        assert(m->sealed);
+
+        if (m->n_iovec > 0)
+                return 0;
+
+        assert(!m->iovec);
+
+        n = 1 + m->n_body_parts;
+        if (n < ELEMENTSOF(m->iovec_fixed))
+                m->iovec = m->iovec_fixed;
+        else {
+                m->iovec = new(struct iovec, n);
+                if (!m->iovec) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m));
+        if (r < 0)
+                goto fail;
+
+        MESSAGE_FOREACH_PART(part, i, m)  {
+                r = bus_body_part_map(part);
+                if (r < 0)
+                        goto fail;
+
+                r = append_iovec(m, part->data, part->size);
+                if (r < 0)
+                        goto fail;
+        }
+
+        assert(n == m->n_iovec);
+
+        return 0;
+
+fail:
+        m->poisoned = true;
+        return r;
+}
+
+bool bus_socket_auth_needs_write(sd_bus *b) {
+
+        unsigned i;
+
+        if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
+                return false;
+
+        for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) {
+                struct iovec *j = b->auth_iovec + i;
+
+                if (j->iov_len > 0)
+                        return true;
+        }
+
+        return false;
+}
+
+static int bus_socket_write_auth(sd_bus *b) {
+        ssize_t k;
+
+        assert(b);
+        assert(b->state == BUS_AUTHENTICATING);
+
+        if (!bus_socket_auth_needs_write(b))
+                return 0;
+
+        if (b->prefer_writev)
+                k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
+        else {
+                struct msghdr mh = {
+                        .msg_iov = b->auth_iovec + b->auth_index,
+                        .msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index,
+                };
+
+                k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+                if (k < 0 && errno == ENOTSOCK) {
+                        b->prefer_writev = true;
+                        k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
+                }
+        }
+
+        if (k < 0)
+                return errno == EAGAIN ? 0 : -errno;
+
+        iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
+        return 1;
+}
+
+static int bus_socket_auth_verify_client(sd_bus *b) {
+        char *d, *e, *f, *start;
+        sd_id128_t peer;
+        int r;
+
+        assert(b);
+
+        /*
+         * We expect three response lines:
+         *   "DATA\r\n"
+         *   "OK <server-id>\r\n"
+         *   "AGREE_UNIX_FD\r\n"        (optional)
+         */
+
+        d = memmem_safe(b->rbuffer, b->rbuffer_size, "\r\n", 2);
+        if (!d)
+                return 0;
+
+        e = memmem(d + 2, b->rbuffer_size - (d - (char*) b->rbuffer) - 2, "\r\n", 2);
+        if (!e)
+                return 0;
+
+        if (b->accept_fd) {
+                f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
+                if (!f)
+                        return 0;
+
+                start = f + 2;
+        } else {
+                f = NULL;
+                start = e + 2;
+        }
+
+        /* Nice! We got all the lines we need. First check the DATA line. */
+
+        if (d - (char*) b->rbuffer == 4) {
+                if (memcmp(b->rbuffer, "DATA", 4))
+                        return -EPERM;
+        } else if (d - (char*) b->rbuffer == 3 + 32) {
+                /*
+                 * Old versions of the server-side implementation of `sd-bus` replied with "OK <id>" to
+                 * "AUTH" requests from a client, even if the "AUTH" line did not contain inlined
+                 * arguments. Therefore, we also accept "OK <id>" here, even though it is technically the
+                 * wrong reply. We ignore the "<id>" parameter, though, since it has no real value.
+                 */
+                if (memcmp(b->rbuffer, "OK ", 3))
+                        return -EPERM;
+        } else
+                return -EPERM;
+
+        /* Now check the OK line. */
+
+        if (e - d != 2 + 3 + 32)
+                return -EPERM;
+
+        if (memcmp(d + 2, "OK ", 3))
+                return -EPERM;
+
+        b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL;
+
+        for (unsigned i = 0; i < 32; i += 2) {
+                int x, y;
+
+                x = unhexchar(d[2 + 3 + i]);
+                y = unhexchar(d[2 + 3 + i + 1]);
+
+                if (x < 0 || y < 0)
+                        return -EINVAL;
+
+                peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y);
+        }
+
+        if (!sd_id128_is_null(b->server_id) &&
+            !sd_id128_equal(b->server_id, peer))
+                return -EPERM;
+
+        b->server_id = peer;
+
+        /* And possibly check the third line, too */
+
+        if (f)
+                b->can_fds =
+                        (f - e == STRLEN("\r\nAGREE_UNIX_FD")) &&
+                        memcmp(e + 2, "AGREE_UNIX_FD",
+                               STRLEN("AGREE_UNIX_FD")) == 0;
+
+        b->rbuffer_size -= (start - (char*) b->rbuffer);
+        memmove(b->rbuffer, start, b->rbuffer_size);
+
+        r = bus_start_running(b);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static bool line_equals(const char *s, size_t m, const char *line) {
+        size_t l;
+
+        l = strlen(line);
+        if (l != m)
+                return false;
+
+        return memcmp(s, line, l) == 0;
+}
+
+static bool line_begins(const char *s, size_t m, const char *word) {
+        const char *p;
+
+        p = memory_startswith(s, m, word);
+        return p && (p == (s + m) || *p == ' ');
+}
+
+static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
+        _cleanup_free_ char *token = NULL;
+        size_t len;
+        int r;
+
+        if (!b->anonymous_auth)
+                return 0;
+
+        if (l <= 0)
+                return 1;
+
+        assert(p[0] == ' ');
+        p++; l--;
+
+        if (l % 2 != 0)
+                return 0;
+
+        r = unhexmem(p, l, (void **) &token, &len);
+        if (r < 0)
+                return 0;
+
+        if (memchr(token, 0, len))
+                return 0;
+
+        return !!utf8_is_valid(token);
+}
+
+static int verify_external_token(sd_bus *b, const char *p, size_t l) {
+        _cleanup_free_ char *token = NULL;
+        size_t len;
+        uid_t u;
+        int r;
+
+        /* We don't do any real authentication here. Instead, we if
+         * the owner of this bus wanted authentication he should have
+         * checked SO_PEERCRED before even creating the bus object. */
+
+        if (!b->anonymous_auth && !b->ucred_valid)
+                return 0;
+
+        if (l <= 0)
+                return 1;
+
+        assert(p[0] == ' ');
+        p++; l--;
+
+        if (l % 2 != 0)
+                return 0;
+
+        r = unhexmem(p, l, (void**) &token, &len);
+        if (r < 0)
+                return 0;
+
+        if (memchr(token, 0, len))
+                return 0;
+
+        r = parse_uid(token, &u);
+        if (r < 0)
+                return 0;
+
+        /* We ignore the passed value if anonymous authentication is
+         * on anyway. */
+        if (!b->anonymous_auth && u != b->ucred.uid)
+                return 0;
+
+        return 1;
+}
+
+static int bus_socket_auth_write(sd_bus *b, const char *t) {
+        char *p;
+        size_t l;
+
+        assert(b);
+        assert(t);
+
+        /* We only make use of the first iovec */
+        assert(IN_SET(b->auth_index, 0, 1));
+
+        l = strlen(t);
+        p = malloc(b->auth_iovec[0].iov_len + l);
+        if (!p)
+                return -ENOMEM;
+
+        memcpy_safe(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len);
+        memcpy(p + b->auth_iovec[0].iov_len, t, l);
+
+        b->auth_iovec[0].iov_base = p;
+        b->auth_iovec[0].iov_len += l;
+
+        free(b->auth_buffer);
+        b->auth_buffer = p;
+        b->auth_index = 0;
+        return 0;
+}
+
+static int bus_socket_auth_write_ok(sd_bus *b) {
+        char t[3 + 32 + 2 + 1];
+
+        assert(b);
+
+        xsprintf(t, "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->server_id));
+
+        return bus_socket_auth_write(b, t);
+}
+
+static int bus_socket_auth_verify_server(sd_bus *b) {
+        char *e;
+        const char *line;
+        size_t l;
+        bool processed = false;
+        int r;
+
+        assert(b);
+
+        if (b->rbuffer_size < 1)
+                return 0;
+
+        /* First char must be a NUL byte */
+        if (*(char*) b->rbuffer != 0)
+                return -EIO;
+
+        if (b->rbuffer_size < 3)
+                return 0;
+
+        /* Begin with the first line */
+        if (b->auth_rbegin <= 0)
+                b->auth_rbegin = 1;
+
+        for (;;) {
+                /* Check if line is complete */
+                line = (char*) b->rbuffer + b->auth_rbegin;
+                e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
+                if (!e)
+                        return processed;
+
+                l = e - line;
+
+                if (line_begins(line, l, "AUTH ANONYMOUS")) {
+
+                        r = verify_anonymous_token(b,
+                                                   line + strlen("AUTH ANONYMOUS"),
+                                                   l - strlen("AUTH ANONYMOUS"));
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                r = bus_socket_auth_write(b, "REJECTED\r\n");
+                        else {
+                                b->auth = BUS_AUTH_ANONYMOUS;
+                                if (l <= strlen("AUTH ANONYMOUS"))
+                                        r = bus_socket_auth_write(b, "DATA\r\n");
+                                else
+                                        r = bus_socket_auth_write_ok(b);
+                        }
+
+                } else if (line_begins(line, l, "AUTH EXTERNAL")) {
+
+                        r = verify_external_token(b,
+                                                  line + strlen("AUTH EXTERNAL"),
+                                                  l - strlen("AUTH EXTERNAL"));
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                r = bus_socket_auth_write(b, "REJECTED\r\n");
+                        else {
+                                b->auth = BUS_AUTH_EXTERNAL;
+                                if (l <= strlen("AUTH EXTERNAL"))
+                                        r = bus_socket_auth_write(b, "DATA\r\n");
+                                else
+                                        r = bus_socket_auth_write_ok(b);
+                        }
+
+                } else if (line_begins(line, l, "AUTH"))
+                        r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n");
+                else if (line_equals(line, l, "CANCEL") ||
+                         line_begins(line, l, "ERROR")) {
+
+                        b->auth = _BUS_AUTH_INVALID;
+                        r = bus_socket_auth_write(b, "REJECTED\r\n");
+
+                } else if (line_equals(line, l, "BEGIN")) {
+
+                        if (b->auth == _BUS_AUTH_INVALID)
+                                r = bus_socket_auth_write(b, "ERROR\r\n");
+                        else {
+                                /* We can't leave from the auth phase
+                                 * before we haven't written
+                                 * everything queued, so let's check
+                                 * that */
+
+                                if (bus_socket_auth_needs_write(b))
+                                        return 1;
+
+                                b->rbuffer_size -= (e + 2 - (char*) b->rbuffer);
+                                memmove(b->rbuffer, e + 2, b->rbuffer_size);
+                                return bus_start_running(b);
+                        }
+
+                } else if (line_begins(line, l, "DATA")) {
+
+                        if (b->auth == _BUS_AUTH_INVALID)
+                                r = bus_socket_auth_write(b, "ERROR\r\n");
+                        else {
+                                if (b->auth == BUS_AUTH_ANONYMOUS)
+                                        r = verify_anonymous_token(b, line + 4, l - 4);
+                                else
+                                        r = verify_external_token(b, line + 4, l - 4);
+
+                                if (r < 0)
+                                        return r;
+                                if (r == 0) {
+                                        b->auth = _BUS_AUTH_INVALID;
+                                        r = bus_socket_auth_write(b, "REJECTED\r\n");
+                                } else
+                                        r = bus_socket_auth_write_ok(b);
+                        }
+                } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) {
+                        if (b->auth == _BUS_AUTH_INVALID || !b->accept_fd)
+                                r = bus_socket_auth_write(b, "ERROR\r\n");
+                        else {
+                                b->can_fds = true;
+                                r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n");
+                        }
+                } else
+                        r = bus_socket_auth_write(b, "ERROR\r\n");
+
+                if (r < 0)
+                        return r;
+
+                b->auth_rbegin = e + 2 - (char*) b->rbuffer;
+
+                processed = true;
+        }
+}
+
+static int bus_socket_auth_verify(sd_bus *b) {
+        assert(b);
+
+        if (b->is_server)
+                return bus_socket_auth_verify_server(b);
+        else
+                return bus_socket_auth_verify_client(b);
+}
+
+static int bus_socket_read_auth(sd_bus *b) {
+        struct msghdr mh;
+        struct iovec iov = {};
+        size_t n;
+        ssize_t k;
+        int r;
+        void *p;
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)) control;
+        bool handle_cmsg = false;
+
+        assert(b);
+        assert(b->state == BUS_AUTHENTICATING);
+
+        r = bus_socket_auth_verify(b);
+        if (r != 0)
+                return r;
+
+        n = MAX(256u, b->rbuffer_size * 2);
+
+        if (n > BUS_AUTH_SIZE_MAX)
+                n = BUS_AUTH_SIZE_MAX;
+
+        if (b->rbuffer_size >= n)
+                return -ENOBUFS;
+
+        p = realloc(b->rbuffer, n);
+        if (!p)
+                return -ENOMEM;
+
+        b->rbuffer = p;
+
+        iov = IOVEC_MAKE((uint8_t *)b->rbuffer + b->rbuffer_size, n - b->rbuffer_size);
+
+        if (b->prefer_readv) {
+                k = readv(b->input_fd, &iov, 1);
+                if (k < 0)
+                        k = -errno;
+        } else {
+                mh = (struct msghdr) {
+                        .msg_iov = &iov,
+                        .msg_iovlen = 1,
+                        .msg_control = &control,
+                        .msg_controllen = sizeof(control),
+                };
+
+                k = recvmsg_safe(b->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
+                if (k == -ENOTSOCK) {
+                        b->prefer_readv = true;
+                        k = readv(b->input_fd, &iov, 1);
+                        if (k < 0)
+                                k = -errno;
+                } else
+                        handle_cmsg = true;
+        }
+        if (k == -EAGAIN)
+                return 0;
+        if (k < 0)
+                return (int) k;
+        if (k == 0) {
+                if (handle_cmsg)
+                        cmsg_close_all(&mh); /* paranoia, we shouldn't have gotten any fds on EOF */
+                return -ECONNRESET;
+        }
+
+        b->rbuffer_size += k;
+
+        if (handle_cmsg) {
+                struct cmsghdr *cmsg;
+
+                CMSG_FOREACH(cmsg, &mh)
+                        if (cmsg->cmsg_level == SOL_SOCKET &&
+                            cmsg->cmsg_type == SCM_RIGHTS) {
+                                int j;
+
+                                /* Whut? We received fds during the auth
+                                 * protocol? Somebody is playing games with
+                                 * us. Close them all, and fail */
+                                j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+                                close_many((int*) CMSG_DATA(cmsg), j);
+                                return -EIO;
+                        } else
+                                log_debug("Got unexpected auxiliary data with level=%d and type=%d",
+                                          cmsg->cmsg_level, cmsg->cmsg_type);
+        }
+
+        r = bus_socket_auth_verify(b);
+        if (r != 0)
+                return r;
+
+        return 1;
+}
+
+void bus_socket_setup(sd_bus *b) {
+        assert(b);
+
+        /* Increase the buffers to 8 MB */
+        (void) fd_inc_rcvbuf(b->input_fd, SNDBUF_SIZE);
+        (void) fd_inc_sndbuf(b->output_fd, SNDBUF_SIZE);
+
+        b->message_version = 1;
+        b->message_endian = 0;
+}
+
+static void bus_get_peercred(sd_bus *b) {
+        int r;
+
+        assert(b);
+        assert(!b->ucred_valid);
+        assert(!b->label);
+        assert(b->n_groups == (size_t) -1);
+
+        /* Get the peer for socketpair() sockets */
+        b->ucred_valid = getpeercred(b->input_fd, &b->ucred) >= 0;
+
+        /* Get the SELinux context of the peer */
+        r = getpeersec(b->input_fd, &b->label);
+        if (r < 0 && !IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
+                log_debug_errno(r, "Failed to determine peer security context: %m");
+
+        /* Get the list of auxiliary groups of the peer */
+        r = getpeergroups(b->input_fd, &b->groups);
+        if (r >= 0)
+                b->n_groups = (size_t) r;
+        else if (!IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
+                log_debug_errno(r, "Failed to determine peer's group list: %m");
+}
+
+static int bus_socket_start_auth_client(sd_bus *b) {
+        static const char sasl_auth_anonymous[] = {
+                /*
+                 * We use an arbitrary trace-string for the ANONYMOUS authentication. It can be used by the
+                 * message broker to aid debugging of clients. We fully anonymize the connection and use a
+                 * static default.
+                 */
+                "\0AUTH ANONYMOUS\r\n"
+                /* HEX a n o n y m o u s */
+                "DATA 616e6f6e796d6f7573\r\n"
+        };
+        static const char sasl_auth_external[] = {
+                "\0AUTH EXTERNAL\r\n"
+                "DATA\r\n"
+        };
+        static const char sasl_negotiate_unix_fd[] = {
+                "NEGOTIATE_UNIX_FD\r\n"
+        };
+        static const char sasl_begin[] = {
+                "BEGIN\r\n"
+        };
+        size_t i = 0;
+
+        assert(b);
+
+        if (b->anonymous_auth)
+                b->auth_iovec[i++] = IOVEC_MAKE((char*) sasl_auth_anonymous, sizeof(sasl_auth_anonymous) - 1);
+        else
+                b->auth_iovec[i++] = IOVEC_MAKE((char*) sasl_auth_external, sizeof(sasl_auth_external) - 1);
+
+        if (b->accept_fd)
+                b->auth_iovec[i++] = IOVEC_MAKE_STRING(sasl_negotiate_unix_fd);
+
+        b->auth_iovec[i++] = IOVEC_MAKE_STRING(sasl_begin);
+
+        return bus_socket_write_auth(b);
+}
+
+int bus_socket_start_auth(sd_bus *b) {
+        assert(b);
+
+        bus_get_peercred(b);
+
+        bus_set_state(b, BUS_AUTHENTICATING);
+        b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_AUTH_TIMEOUT;
+
+        if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0)
+                b->accept_fd = false;
+
+        if (b->output_fd != b->input_fd)
+                if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0)
+                        b->accept_fd = false;
+
+        if (b->is_server)
+                return bus_socket_read_auth(b);
+        else
+                return bus_socket_start_auth_client(b);
+}
+
+static int bus_socket_inotify_setup(sd_bus *b) {
+        _cleanup_free_ int *new_watches = NULL;
+        _cleanup_free_ char *absolute = NULL;
+        size_t n_allocated = 0, n = 0, done = 0, i;
+        unsigned max_follow = 32;
+        const char *p;
+        int wd, r;
+
+        assert(b);
+        assert(b->watch_bind);
+        assert(b->sockaddr.sa.sa_family == AF_UNIX);
+        assert(b->sockaddr.un.sun_path[0] != 0);
+
+        /* Sets up an inotify fd in case watch_bind is enabled: wait until the configured AF_UNIX file system socket
+         * appears before connecting to it. The implemented is pretty simplistic: we just subscribe to relevant changes
+         * to all prefix components of the path, and every time we get an event for that we try to reconnect again,
+         * without actually caring what precisely the event we got told us. If we still can't connect we re-subscribe
+         * to all relevant changes of anything in the path, so that our watches include any possibly newly created path
+         * components. */
+
+        if (b->inotify_fd < 0) {
+                b->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+                if (b->inotify_fd < 0)
+                        return -errno;
+
+                b->inotify_fd = fd_move_above_stdio(b->inotify_fd);
+        }
+
+        /* Make sure the path is NUL terminated */
+        p = strndupa(b->sockaddr.un.sun_path, sizeof(b->sockaddr.un.sun_path));
+
+        /* Make sure the path is absolute */
+        r = path_make_absolute_cwd(p, &absolute);
+        if (r < 0)
+                goto fail;
+
+        /* Watch all parent directories, and don't mind any prefix that doesn't exist yet. For the innermost directory
+         * that exists we want to know when files are created or moved into it. For all parents of it we just care if
+         * they are removed or renamed. */
+
+        if (!GREEDY_REALLOC(new_watches, n_allocated, n + 1)) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        /* Start with the top-level directory, which is a bit simpler than the rest, since it can't be a symlink, and
+         * always exists */
+        wd = inotify_add_watch(b->inotify_fd, "/", IN_CREATE|IN_MOVED_TO);
+        if (wd < 0) {
+                r = log_debug_errno(errno, "Failed to add inotify watch on /: %m");
+                goto fail;
+        } else
+                new_watches[n++] = wd;
+
+        for (;;) {
+                _cleanup_free_ char *component = NULL, *prefix = NULL, *destination = NULL;
+                size_t n_slashes, n_component;
+                char *c = NULL;
+
+                n_slashes = strspn(absolute + done, "/");
+                n_component = n_slashes + strcspn(absolute + done + n_slashes, "/");
+
+                if (n_component == 0) /* The end */
+                        break;
+
+                component = strndup(absolute + done, n_component);
+                if (!component) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                /* A trailing slash? That's a directory, and not a socket then */
+                if (path_equal(component, "/")) {
+                        r = -EISDIR;
+                        goto fail;
+                }
+
+                /* A single dot? Let's eat this up */
+                if (path_equal(component, "/.")) {
+                        done += n_component;
+                        continue;
+                }
+
+                prefix = strndup(absolute, done + n_component);
+                if (!prefix) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                if (!GREEDY_REALLOC(new_watches, n_allocated, n + 1)) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                wd = inotify_add_watch(b->inotify_fd, prefix, IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO|IN_DONT_FOLLOW);
+                log_debug("Added inotify watch for %s on bus %s: %i", prefix, strna(b->description), wd);
+
+                if (wd < 0) {
+                        if (IN_SET(errno, ENOENT, ELOOP))
+                                break; /* This component doesn't exist yet, or the path contains a cyclic symlink right now */
+
+                        r = log_debug_errno(errno, "Failed to add inotify watch on %s: %m", empty_to_root(prefix));
+                        goto fail;
+                } else
+                        new_watches[n++] = wd;
+
+                /* Check if this is possibly a symlink. If so, let's follow it and watch it too. */
+                r = readlink_malloc(prefix, &destination);
+                if (r == -EINVAL) { /* not a symlink */
+                        done += n_component;
+                        continue;
+                }
+                if (r < 0)
+                        goto fail;
+
+                if (isempty(destination)) { /* Empty symlink target? Yuck! */
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+                if (max_follow <= 0) { /* Let's make sure we don't follow symlinks forever */
+                        r = -ELOOP;
+                        goto fail;
+                }
+
+                if (path_is_absolute(destination)) {
+                        /* For absolute symlinks we build the new path and start anew */
+                        c = strjoin(destination, absolute + done + n_component);
+                        done = 0;
+                } else {
+                        _cleanup_free_ char *t = NULL;
+
+                        /* For relative symlinks we replace the last component, and try again */
+                        t = strndup(absolute, done);
+                        if (!t)
+                                return -ENOMEM;
+
+                        c = strjoin(t, "/", destination, absolute + done + n_component);
+                }
+                if (!c) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                free(absolute);
+                absolute = c;
+
+                max_follow--;
+        }
+
+        /* And now, let's remove all watches from the previous iteration we don't need anymore */
+        for (i = 0; i < b->n_inotify_watches; i++) {
+                bool found = false;
+                size_t j;
+
+                for (j = 0; j < n; j++)
+                        if (new_watches[j] == b->inotify_watches[i]) {
+                                found = true;
+                                break;
+                        }
+
+                if (found)
+                        continue;
+
+                (void) inotify_rm_watch(b->inotify_fd, b->inotify_watches[i]);
+        }
+
+        free_and_replace(b->inotify_watches, new_watches);
+        b->n_inotify_watches = n;
+
+        return 0;
+
+fail:
+        bus_close_inotify_fd(b);
+        return r;
+}
+
+int bus_socket_connect(sd_bus *b) {
+        bool inotify_done = false;
+        int r;
+
+        assert(b);
+
+        for (;;) {
+                assert(b->input_fd < 0);
+                assert(b->output_fd < 0);
+                assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
+
+                if (DEBUG_LOGGING) {
+                        _cleanup_free_ char *pretty = NULL;
+                        (void) sockaddr_pretty(&b->sockaddr.sa, b->sockaddr_size, false, true, &pretty);
+                        log_debug("sd-bus: starting bus%s%s by connecting to %s...",
+                                  b->description ? " " : "", strempty(b->description), strnull(pretty));
+                }
+
+                b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+                if (b->input_fd < 0)
+                        return -errno;
+
+                b->input_fd = fd_move_above_stdio(b->input_fd);
+
+                b->output_fd = b->input_fd;
+                bus_socket_setup(b);
+
+                if (connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size) < 0) {
+                        if (errno == EINPROGRESS) {
+
+                                /* If we have any inotify watches open, close them now, we don't need them anymore, as
+                                 * we have successfully initiated a connection */
+                                bus_close_inotify_fd(b);
+
+                                /* Note that very likely we are already in BUS_OPENING state here, as we enter it when
+                                 * we start parsing the address string. The only reason we set the state explicitly
+                                 * here, is to undo BUS_WATCH_BIND, in case we did the inotify magic. */
+                                bus_set_state(b, BUS_OPENING);
+                                return 1;
+                        }
+
+                        if (IN_SET(errno, ENOENT, ECONNREFUSED) &&  /* ENOENT → unix socket doesn't exist at all; ECONNREFUSED → unix socket stale */
+                            b->watch_bind &&
+                            b->sockaddr.sa.sa_family == AF_UNIX &&
+                            b->sockaddr.un.sun_path[0] != 0) {
+
+                                /* This connection attempt failed, let's release the socket for now, and start with a
+                                 * fresh one when reconnecting. */
+                                bus_close_io_fds(b);
+
+                                if (inotify_done) {
+                                        /* inotify set up already, don't do it again, just return now, and remember
+                                         * that we are waiting for inotify events now. */
+                                        bus_set_state(b, BUS_WATCH_BIND);
+                                        return 1;
+                                }
+
+                                /* This is a file system socket, and the inotify logic is enabled. Let's create the necessary inotify fd. */
+                                r = bus_socket_inotify_setup(b);
+                                if (r < 0)
+                                        return r;
+
+                                /* Let's now try to connect a second time, because in theory there's otherwise a race
+                                 * here: the socket might have been created in the time between our first connect() and
+                                 * the time we set up the inotify logic. But let's remember that we set up inotify now,
+                                 * so that we don't do the connect() more than twice. */
+                                inotify_done = true;
+
+                        } else
+                                return -errno;
+                } else
+                        break;
+        }
+
+        /* Yay, established, we don't need no inotify anymore! */
+        bus_close_inotify_fd(b);
+
+        return bus_socket_start_auth(b);
+}
+
+int bus_socket_exec(sd_bus *b) {
+        int s[2], r;
+
+        assert(b);
+        assert(b->input_fd < 0);
+        assert(b->output_fd < 0);
+        assert(b->exec_path);
+        assert(b->busexec_pid == 0);
+
+        log_debug("sd-bus: starting bus%s%s with %s...",
+                  b->description ? " " : "", strempty(b->description), b->exec_path);
+
+        r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
+        if (r < 0)
+                return -errno;
+
+        r = safe_fork_full("(sd-busexec)", s+1, 1, FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &b->busexec_pid);
+        if (r < 0) {
+                safe_close_pair(s);
+                return r;
+        }
+        if (r == 0) {
+                /* Child */
+
+                if (rearrange_stdio(s[1], s[1], STDERR_FILENO) < 0)
+                        _exit(EXIT_FAILURE);
+
+                (void) rlimit_nofile_safe();
+
+                if (b->exec_argv)
+                        execvp(b->exec_path, b->exec_argv);
+                else {
+                        const char *argv[] = { b->exec_path, NULL };
+                        execvp(b->exec_path, (char**) argv);
+                }
+
+                _exit(EXIT_FAILURE);
+        }
+
+        safe_close(s[1]);
+        b->output_fd = b->input_fd = fd_move_above_stdio(s[0]);
+
+        bus_socket_setup(b);
+
+        return bus_socket_start_auth(b);
+}
+
+int bus_socket_take_fd(sd_bus *b) {
+        assert(b);
+
+        bus_socket_setup(b);
+
+        return bus_socket_start_auth(b);
+}
+
+int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
+        struct iovec *iov;
+        ssize_t k;
+        size_t n;
+        unsigned j;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(idx);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        if (*idx >= BUS_MESSAGE_SIZE(m))
+                return 0;
+
+        r = bus_message_setup_iovec(m);
+        if (r < 0)
+                return r;
+
+        n = m->n_iovec * sizeof(struct iovec);
+        iov = newa(struct iovec, n);
+        memcpy_safe(iov, m->iovec, n);
+
+        j = 0;
+        iovec_advance(iov, &j, *idx);
+
+        if (bus->prefer_writev)
+                k = writev(bus->output_fd, iov, m->n_iovec);
+        else {
+                struct msghdr mh = {
+                        .msg_iov = iov,
+                        .msg_iovlen = m->n_iovec,
+                };
+
+                if (m->n_fds > 0 && *idx == 0) {
+                        struct cmsghdr *control;
+
+                        mh.msg_controllen = CMSG_SPACE(sizeof(int) * m->n_fds);
+                        mh.msg_control = alloca0(mh.msg_controllen);
+                        control = CMSG_FIRSTHDR(&mh);
+                        control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
+                        control->cmsg_level = SOL_SOCKET;
+                        control->cmsg_type = SCM_RIGHTS;
+                        memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
+                }
+
+                k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+                if (k < 0 && errno == ENOTSOCK) {
+                        bus->prefer_writev = true;
+                        k = writev(bus->output_fd, iov, m->n_iovec);
+                }
+        }
+
+        if (k < 0)
+                return errno == EAGAIN ? 0 : -errno;
+
+        *idx += (size_t) k;
+        return 1;
+}
+
+static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
+        uint32_t a, b;
+        uint8_t e;
+        uint64_t sum;
+
+        assert(bus);
+        assert(need);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        if (bus->rbuffer_size < sizeof(struct bus_header)) {
+                *need = sizeof(struct bus_header) + 8;
+
+                /* Minimum message size:
+                 *
+                 * Header +
+                 *
+                 *  Method Call: +2 string headers
+                 *       Signal: +3 string headers
+                 * Method Error: +1 string headers
+                 *               +1 uint32 headers
+                 * Method Reply: +1 uint32 headers
+                 *
+                 * A string header is at least 9 bytes
+                 * A uint32 header is at least 8 bytes
+                 *
+                 * Hence the minimum message size of a valid message
+                 * is header + 8 bytes */
+
+                return 0;
+        }
+
+        a = ((const uint32_t*) bus->rbuffer)[1];
+        b = ((const uint32_t*) bus->rbuffer)[3];
+
+        e = ((const uint8_t*) bus->rbuffer)[0];
+        if (e == BUS_LITTLE_ENDIAN) {
+                a = le32toh(a);
+                b = le32toh(b);
+        } else if (e == BUS_BIG_ENDIAN) {
+                a = be32toh(a);
+                b = be32toh(b);
+        } else
+                return -EBADMSG;
+
+        sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a;
+        if (sum >= BUS_MESSAGE_SIZE_MAX)
+                return -ENOBUFS;
+
+        *need = (size_t) sum;
+        return 0;
+}
+
+static int bus_socket_make_message(sd_bus *bus, size_t size) {
+        sd_bus_message *t = NULL;
+        void *b;
+        int r;
+
+        assert(bus);
+        assert(bus->rbuffer_size >= size);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
+        if (bus->rbuffer_size > size) {
+                b = memdup((const uint8_t*) bus->rbuffer + size,
+                           bus->rbuffer_size - size);
+                if (!b)
+                        return -ENOMEM;
+        } else
+                b = NULL;
+
+        r = bus_message_from_malloc(bus,
+                                    bus->rbuffer, size,
+                                    bus->fds, bus->n_fds,
+                                    NULL,
+                                    &t);
+        if (r == -EBADMSG) {
+                log_debug_errno(r, "Received invalid message from connection %s, dropping.", strna(bus->description));
+                free(bus->rbuffer); /* We want to drop current rbuffer and proceed with whatever remains in b */
+        } else if (r < 0) {
+                free(b);
+                return r;
+        }
+
+        /* rbuffer ownership was either transferred to t, or we got EBADMSG and dropped it. */
+        bus->rbuffer = b;
+        bus->rbuffer_size -= size;
+
+        bus->fds = NULL;
+        bus->n_fds = 0;
+
+        if (t) {
+                t->read_counter = ++bus->read_counter;
+                bus->rqueue[bus->rqueue_size++] = bus_message_ref_queued(t, bus);
+                sd_bus_message_unref(t);
+        }
+
+        return 1;
+}
+
+int bus_socket_read_message(sd_bus *bus) {
+        struct msghdr mh;
+        struct iovec iov = {};
+        ssize_t k;
+        size_t need;
+        int r;
+        void *b;
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)) control;
+        bool handle_cmsg = false;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        r = bus_socket_read_message_need(bus, &need);
+        if (r < 0)
+                return r;
+
+        if (bus->rbuffer_size >= need)
+                return bus_socket_make_message(bus, need);
+
+        b = realloc(bus->rbuffer, need);
+        if (!b)
+                return -ENOMEM;
+
+        bus->rbuffer = b;
+
+        iov = IOVEC_MAKE((uint8_t *)bus->rbuffer + bus->rbuffer_size, need - bus->rbuffer_size);
+
+        if (bus->prefer_readv) {
+                k = readv(bus->input_fd, &iov, 1);
+                if (k < 0)
+                        k = -errno;
+        } else {
+                mh = (struct msghdr) {
+                        .msg_iov = &iov,
+                        .msg_iovlen = 1,
+                        .msg_control = &control,
+                        .msg_controllen = sizeof(control),
+                };
+
+                k = recvmsg_safe(bus->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
+                if (k == -ENOTSOCK) {
+                        bus->prefer_readv = true;
+                        k = readv(bus->input_fd, &iov, 1);
+                        if (k < 0)
+                                k = -errno;
+                } else
+                        handle_cmsg = true;
+        }
+        if (k == -EAGAIN)
+                return 0;
+        if (k < 0)
+                return (int) k;
+        if (k == 0) {
+                if (handle_cmsg)
+                        cmsg_close_all(&mh); /* On EOF we shouldn't have gotten an fd, but let's make sure */
+                return -ECONNRESET;
+        }
+
+        bus->rbuffer_size += k;
+
+        if (handle_cmsg) {
+                struct cmsghdr *cmsg;
+
+                CMSG_FOREACH(cmsg, &mh)
+                        if (cmsg->cmsg_level == SOL_SOCKET &&
+                            cmsg->cmsg_type == SCM_RIGHTS) {
+                                int n, *f, i;
+
+                                n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+
+                                if (!bus->can_fds) {
+                                        /* Whut? We received fds but this
+                                         * isn't actually enabled? Close them,
+                                         * and fail */
+
+                                        close_many((int*) CMSG_DATA(cmsg), n);
+                                        return -EIO;
+                                }
+
+                                f = reallocarray(bus->fds, bus->n_fds + n, sizeof(int));
+                                if (!f) {
+                                        close_many((int*) CMSG_DATA(cmsg), n);
+                                        return -ENOMEM;
+                                }
+
+                                for (i = 0; i < n; i++)
+                                        f[bus->n_fds++] = fd_move_above_stdio(((int*) CMSG_DATA(cmsg))[i]);
+                                bus->fds = f;
+                        } else
+                                log_debug("Got unexpected auxiliary data with level=%d and type=%d",
+                                          cmsg->cmsg_level, cmsg->cmsg_type);
+        }
+
+        r = bus_socket_read_message_need(bus, &need);
+        if (r < 0)
+                return r;
+
+        if (bus->rbuffer_size >= need)
+                return bus_socket_make_message(bus, need);
+
+        return 1;
+}
+
+int bus_socket_process_opening(sd_bus *b) {
+        int error = 0, events, r;
+        socklen_t slen = sizeof(error);
+
+        assert(b->state == BUS_OPENING);
+
+        events = fd_wait_for_event(b->output_fd, POLLOUT, 0);
+        if (events < 0)
+                return events;
+        if (!(events & (POLLOUT|POLLERR|POLLHUP)))
+                return 0;
+
+        r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen);
+        if (r < 0)
+                b->last_connect_error = errno;
+        else if (error != 0)
+                b->last_connect_error = error;
+        else if (events & (POLLERR|POLLHUP))
+                b->last_connect_error = ECONNREFUSED;
+        else
+                return bus_socket_start_auth(b);
+
+        return bus_next_address(b);
+}
+
+int bus_socket_process_authenticating(sd_bus *b) {
+        int r;
+
+        assert(b);
+        assert(b->state == BUS_AUTHENTICATING);
+
+        if (now(CLOCK_MONOTONIC) >= b->auth_timeout)
+                return -ETIMEDOUT;
+
+        r = bus_socket_write_auth(b);
+        if (r != 0)
+                return r;
+
+        return bus_socket_read_auth(b);
+}
+
+int bus_socket_process_watch_bind(sd_bus *b) {
+        int r, q;
+
+        assert(b);
+        assert(b->state == BUS_WATCH_BIND);
+        assert(b->inotify_fd >= 0);
+
+        r = flush_fd(b->inotify_fd);
+        if (r <= 0)
+                return r;
+
+        log_debug("Got inotify event on bus %s.", strna(b->description));
+
+        /* We flushed events out of the inotify fd. In that case, maybe the socket is valid now? Let's try to connect
+         * to it again */
+
+        r = bus_socket_connect(b);
+        if (r < 0)
+                return r;
+
+        q = bus_attach_io_events(b);
+        if (q < 0)
+                return q;
+
+        q = bus_attach_inotify_event(b);
+        if (q < 0)
+                return q;
+
+        return r;
+}
diff --git a/src/libsystemd/sd-bus/bus-socket.h b/src/libsystemd/sd-bus/bus-socket.h
new file mode 100644
index 0000000..52bc404
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-socket.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+void bus_socket_setup(sd_bus *b);
+
+int bus_socket_connect(sd_bus *b);
+int bus_socket_exec(sd_bus *b);
+int bus_socket_take_fd(sd_bus *b);
+int bus_socket_start_auth(sd_bus *b);
+
+int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx);
+int bus_socket_read_message(sd_bus *bus);
+
+int bus_socket_process_opening(sd_bus *b);
+int bus_socket_process_authenticating(sd_bus *b);
+int bus_socket_process_watch_bind(sd_bus *b);
+
+bool bus_socket_auth_needs_write(sd_bus *b);
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
new file mode 100644
index 0000000..5f8716e
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -0,0 +1,493 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-track.h"
+#include "bus-util.h"
+#include "string-util.h"
+
+struct track_item {
+        unsigned n_ref;
+        char *name;
+        sd_bus_slot *slot;
+};
+
+struct sd_bus_track {
+        unsigned n_ref;
+        unsigned n_adding; /* are we in the process of adding a new name? */
+        sd_bus *bus;
+        sd_bus_track_handler_t handler;
+        void *userdata;
+        Hashmap *names;
+        LIST_FIELDS(sd_bus_track, queue);
+        Iterator iterator;
+        bool in_list:1;    /* In bus->tracks? */
+        bool in_queue:1;   /* In bus->track_queue? */
+        bool modified:1;
+        bool recursive:1;
+        sd_bus_destroy_t destroy_callback;
+
+        LIST_FIELDS(sd_bus_track, tracks);
+};
+
+#define MATCH_FOR_NAME(name)                            \
+        strjoina("type='signal',"                       \
+                 "sender='org.freedesktop.DBus',"       \
+                 "path='/org/freedesktop/DBus',"        \
+                 "interface='org.freedesktop.DBus',"    \
+                 "member='NameOwnerChanged',"           \
+                 "arg0='", name, "'")
+
+static struct track_item* track_item_free(struct track_item *i) {
+
+        if (!i)
+                return NULL;
+
+        sd_bus_slot_unref(i->slot);
+        free(i->name);
+        return mfree(i);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct track_item*, track_item_free);
+DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(track_item_hash_ops, char, string_hash_func, string_compare_func,
+                                              struct track_item, track_item_free);
+
+static void bus_track_add_to_queue(sd_bus_track *track) {
+        assert(track);
+
+        /* Adds the bus track object to the queue of objects we should dispatch next, subject to a number of
+         * conditions. */
+
+        /* Already in the queue? */
+        if (track->in_queue)
+                return;
+
+        /* if we are currently in the process of adding a new name, then let's not enqueue this just yet, let's wait
+         * until the addition is complete. */
+        if (track->n_adding > 0)
+                return;
+
+        /* still referenced? */
+        if (hashmap_size(track->names) > 0)
+                return;
+
+        /* Nothing to call? */
+        if (!track->handler)
+                return;
+
+        /* Already closed? */
+        if (!track->in_list)
+                return;
+
+        LIST_PREPEND(queue, track->bus->track_queue, track);
+        track->in_queue = true;
+}
+
+static void bus_track_remove_from_queue(sd_bus_track *track) {
+        assert(track);
+
+        if (!track->in_queue)
+                return;
+
+        LIST_REMOVE(queue, track->bus->track_queue, track);
+        track->in_queue = false;
+}
+
+static int bus_track_remove_name_fully(sd_bus_track *track, const char *name) {
+        struct track_item *i;
+
+        assert(track);
+        assert(name);
+
+        i = hashmap_remove(track->names, name);
+        if (!i)
+                return 0;
+
+        track_item_free(i);
+
+        bus_track_add_to_queue(track);
+
+        track->modified = true;
+        return 1;
+}
+
+_public_ int sd_bus_track_new(
+                sd_bus *bus,
+                sd_bus_track **track,
+                sd_bus_track_handler_t handler,
+                void *userdata) {
+
+        sd_bus_track *t;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(track, -EINVAL);
+
+        if (!bus->bus_client)
+                return -EINVAL;
+
+        t = new0(sd_bus_track, 1);
+        if (!t)
+                return -ENOMEM;
+
+        t->n_ref = 1;
+        t->handler = handler;
+        t->userdata = userdata;
+        t->bus = sd_bus_ref(bus);
+
+        LIST_PREPEND(tracks, bus->tracks, t);
+        t->in_list = true;
+
+        bus_track_add_to_queue(t);
+
+        *track = t;
+        return 0;
+}
+
+static sd_bus_track *track_free(sd_bus_track *track) {
+        assert(track);
+
+        if (track->in_list)
+                LIST_REMOVE(tracks, track->bus->tracks, track);
+
+        bus_track_remove_from_queue(track);
+        track->names = hashmap_free(track->names);
+        track->bus = sd_bus_unref(track->bus);
+
+        if (track->destroy_callback)
+                track->destroy_callback(track->userdata);
+
+        return mfree(track);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_bus_track, sd_bus_track, track_free);
+
+static int on_name_owner_changed(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        sd_bus_track *track = userdata;
+        const char *name, *old, *new;
+        int r;
+
+        assert(message);
+        assert(track);
+
+        r = sd_bus_message_read(message, "sss", &name, &old, &new);
+        if (r < 0)
+                return 0;
+
+        bus_track_remove_name_fully(track, name);
+        return 0;
+}
+
+_public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) {
+        _cleanup_(track_item_freep) struct track_item *n = NULL;
+        struct track_item *i;
+        const char *match;
+        int r;
+
+        assert_return(track, -EINVAL);
+        assert_return(service_name_is_valid(name), -EINVAL);
+
+        i = hashmap_get(track->names, name);
+        if (i) {
+                if (track->recursive) {
+                        unsigned k = track->n_ref + 1;
+
+                        if (k < track->n_ref) /* Check for overflow */
+                                return -EOVERFLOW;
+
+                        track->n_ref = k;
+                }
+
+                bus_track_remove_from_queue(track);
+                return 0;
+        }
+
+        r = hashmap_ensure_allocated(&track->names, &track_item_hash_ops);
+        if (r < 0)
+                return r;
+
+        n = new0(struct track_item, 1);
+        if (!n)
+                return -ENOMEM;
+        n->name = strdup(name);
+        if (!n->name)
+                return -ENOMEM;
+
+        /* First, subscribe to this name */
+        match = MATCH_FOR_NAME(name);
+
+        bus_track_remove_from_queue(track); /* don't dispatch this while we work in it */
+
+        r = sd_bus_add_match_async(track->bus, &n->slot, match, on_name_owner_changed, NULL, track);
+        if (r < 0) {
+                bus_track_add_to_queue(track);
+                return r;
+        }
+
+        r = hashmap_put(track->names, n->name, n);
+        if (r < 0) {
+                bus_track_add_to_queue(track);
+                return r;
+        }
+
+        /* Second, check if it is currently existing, or maybe doesn't, or maybe disappeared already. */
+        track->n_adding++; /* again, make sure this isn't dispatch while we are working in it */
+        r = sd_bus_get_name_creds(track->bus, name, 0, NULL);
+        track->n_adding--;
+        if (r < 0) {
+                hashmap_remove(track->names, name);
+                bus_track_add_to_queue(track);
+                return r;
+        }
+
+        n->n_ref = 1;
+        n = NULL;
+
+        bus_track_remove_from_queue(track);
+        track->modified = true;
+
+        return 1;
+}
+
+_public_ int sd_bus_track_remove_name(sd_bus_track *track, const char *name) {
+        struct track_item *i;
+
+        assert_return(name, -EINVAL);
+
+        if (!track) /* Treat a NULL track object as an empty track object */
+                return 0;
+
+        if (!track->recursive)
+                return bus_track_remove_name_fully(track, name);
+
+        i = hashmap_get(track->names, name);
+        if (!i)
+                return -EUNATCH;
+        if (i->n_ref <= 0)
+                return -EUNATCH;
+
+        i->n_ref--;
+
+        if (i->n_ref <= 0)
+                return bus_track_remove_name_fully(track, name);
+
+        return 1;
+}
+
+_public_ unsigned sd_bus_track_count(sd_bus_track *track) {
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return 0;
+
+        /* This signature really should have returned an int, so that we can propagate errors. But well, ... Also, note
+         * that this returns the number of names being watched, and multiple references to the same name are not
+         * counted. */
+
+        return hashmap_size(track->names);
+}
+
+_public_ const char* sd_bus_track_contains(sd_bus_track *track, const char *name) {
+        assert_return(name, NULL);
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return NULL;
+
+        return hashmap_get(track->names, (void*) name) ? name : NULL;
+}
+
+_public_ const char* sd_bus_track_first(sd_bus_track *track) {
+        const char *n = NULL;
+
+        if (!track)
+                return NULL;
+
+        track->modified = false;
+        track->iterator = ITERATOR_FIRST;
+
+        (void) hashmap_iterate(track->names, &track->iterator, NULL, (const void**) &n);
+        return n;
+}
+
+_public_ const char* sd_bus_track_next(sd_bus_track *track) {
+        const char *n = NULL;
+
+        if (!track)
+                return NULL;
+
+        if (track->modified)
+                return NULL;
+
+        (void) hashmap_iterate(track->names, &track->iterator, NULL, (const void**) &n);
+        return n;
+}
+
+_public_ int sd_bus_track_add_sender(sd_bus_track *track, sd_bus_message *m) {
+        const char *sender;
+
+        assert_return(track, -EINVAL);
+        assert_return(m, -EINVAL);
+
+        if (sd_bus_message_get_bus(m) != track->bus)
+                return -EINVAL;
+
+        sender = sd_bus_message_get_sender(m);
+        if (!sender)
+                return -EINVAL;
+
+        return sd_bus_track_add_name(track, sender);
+}
+
+_public_ int sd_bus_track_remove_sender(sd_bus_track *track, sd_bus_message *m) {
+        const char *sender;
+
+        assert_return(m, -EINVAL);
+
+        if (!track) /* Treat a NULL track object as an empty track object */
+                return 0;
+
+        if (sd_bus_message_get_bus(m) != track->bus)
+                return -EINVAL;
+
+        sender = sd_bus_message_get_sender(m);
+        if (!sender)
+                return -EINVAL;
+
+        return sd_bus_track_remove_name(track, sender);
+}
+
+_public_ sd_bus* sd_bus_track_get_bus(sd_bus_track *track) {
+        assert_return(track, NULL);
+
+        return track->bus;
+}
+
+void bus_track_dispatch(sd_bus_track *track) {
+        int r;
+
+        assert(track);
+        assert(track->handler);
+
+        bus_track_remove_from_queue(track);
+
+        sd_bus_track_ref(track);
+
+        r = track->handler(track, track->userdata);
+        if (r < 0)
+                log_debug_errno(r, "Failed to process track handler: %m");
+        else if (r == 0)
+                bus_track_add_to_queue(track);
+
+        sd_bus_track_unref(track);
+}
+
+void bus_track_close(sd_bus_track *track) {
+        assert(track);
+
+        /* Called whenever our bus connected is closed. If so, and our track object is non-empty, dispatch it
+         * immediately, as we are closing now, but first flush out all names. */
+
+        if (!track->in_list)
+                return; /* We already closed this one, don't close it again. */
+
+        /* Remember that this one is closed now */
+        LIST_REMOVE(tracks, track->bus->tracks, track);
+        track->in_list = false;
+
+        /* If there's no name in this one anyway, we don't have to dispatch */
+        if (hashmap_isempty(track->names))
+                return;
+
+        /* Let's flush out all names */
+        hashmap_clear(track->names);
+
+        /* Invoke handler */
+        if (track->handler)
+                bus_track_dispatch(track);
+}
+
+_public_ void *sd_bus_track_get_userdata(sd_bus_track *track) {
+        assert_return(track, NULL);
+
+        return track->userdata;
+}
+
+_public_ void *sd_bus_track_set_userdata(sd_bus_track *track, void *userdata) {
+        void *ret;
+
+        assert_return(track, NULL);
+
+        ret = track->userdata;
+        track->userdata = userdata;
+
+        return ret;
+}
+
+_public_ int sd_bus_track_set_destroy_callback(sd_bus_track *track, sd_bus_destroy_t callback) {
+        assert_return(track, -EINVAL);
+
+        track->destroy_callback = callback;
+        return 0;
+}
+
+_public_ int sd_bus_track_get_destroy_callback(sd_bus_track *track, sd_bus_destroy_t *ret) {
+        assert_return(track, -EINVAL);
+
+        if (ret)
+                *ret = track->destroy_callback;
+
+        return !!track->destroy_callback;
+}
+
+_public_ int sd_bus_track_set_recursive(sd_bus_track *track, int b) {
+        assert_return(track, -EINVAL);
+
+        if (track->recursive == !!b)
+                return 0;
+
+        if (!hashmap_isempty(track->names))
+                return -EBUSY;
+
+        track->recursive = b;
+        return 0;
+}
+
+_public_ int sd_bus_track_get_recursive(sd_bus_track *track) {
+        assert_return(track, -EINVAL);
+
+        return track->recursive;
+}
+
+_public_ int sd_bus_track_count_sender(sd_bus_track *track, sd_bus_message *m) {
+        const char *sender;
+
+        assert_return(m, -EINVAL);
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return 0;
+
+        if (sd_bus_message_get_bus(m) != track->bus)
+                return -EINVAL;
+
+        sender = sd_bus_message_get_sender(m);
+        if (!sender)
+                return -EINVAL;
+
+        return sd_bus_track_count_name(track, sender);
+}
+
+_public_ int sd_bus_track_count_name(sd_bus_track *track, const char *name) {
+        struct track_item *i;
+
+        assert_return(service_name_is_valid(name), -EINVAL);
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return 0;
+
+        i = hashmap_get(track->names, name);
+        if (!i)
+                return 0;
+
+        return i->n_ref;
+}
diff --git a/src/libsystemd/sd-bus/bus-track.h b/src/libsystemd/sd-bus/bus-track.h
new file mode 100644
index 0000000..8dae1f3
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-track.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+void bus_track_dispatch(sd_bus_track *track);
+void bus_track_close(sd_bus_track *track);
diff --git a/src/libsystemd/sd-bus/bus-type.c b/src/libsystemd/sd-bus/bus-type.c
new file mode 100644
index 0000000..6a0f53d
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-type.c
@@ -0,0 +1,162 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+
+#include "sd-bus.h"
+
+#include "bus-internal.h"
+#include "bus-type.h"
+
+bool bus_type_is_valid(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_BYTE,
+                SD_BUS_TYPE_BOOLEAN,
+                SD_BUS_TYPE_INT16,
+                SD_BUS_TYPE_UINT16,
+                SD_BUS_TYPE_INT32,
+                SD_BUS_TYPE_UINT32,
+                SD_BUS_TYPE_INT64,
+                SD_BUS_TYPE_UINT64,
+                SD_BUS_TYPE_DOUBLE,
+                SD_BUS_TYPE_STRING,
+                SD_BUS_TYPE_OBJECT_PATH,
+                SD_BUS_TYPE_SIGNATURE,
+                SD_BUS_TYPE_ARRAY,
+                SD_BUS_TYPE_VARIANT,
+                SD_BUS_TYPE_STRUCT,
+                SD_BUS_TYPE_DICT_ENTRY,
+                SD_BUS_TYPE_UNIX_FD
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+bool bus_type_is_basic(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_BYTE,
+                SD_BUS_TYPE_BOOLEAN,
+                SD_BUS_TYPE_INT16,
+                SD_BUS_TYPE_UINT16,
+                SD_BUS_TYPE_INT32,
+                SD_BUS_TYPE_UINT32,
+                SD_BUS_TYPE_INT64,
+                SD_BUS_TYPE_UINT64,
+                SD_BUS_TYPE_DOUBLE,
+                SD_BUS_TYPE_STRING,
+                SD_BUS_TYPE_OBJECT_PATH,
+                SD_BUS_TYPE_SIGNATURE,
+                SD_BUS_TYPE_UNIX_FD
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+bool bus_type_is_trivial(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_BYTE,
+                SD_BUS_TYPE_BOOLEAN,
+                SD_BUS_TYPE_INT16,
+                SD_BUS_TYPE_UINT16,
+                SD_BUS_TYPE_INT32,
+                SD_BUS_TYPE_UINT32,
+                SD_BUS_TYPE_INT64,
+                SD_BUS_TYPE_UINT64,
+                SD_BUS_TYPE_DOUBLE
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+bool bus_type_is_container(char c) {
+        static const char valid[] = {
+                SD_BUS_TYPE_ARRAY,
+                SD_BUS_TYPE_VARIANT,
+                SD_BUS_TYPE_STRUCT,
+                SD_BUS_TYPE_DICT_ENTRY
+        };
+
+        return !!memchr(valid, c, sizeof(valid));
+}
+
+int bus_type_get_alignment(char c) {
+
+        switch (c) {
+        case SD_BUS_TYPE_BYTE:
+        case SD_BUS_TYPE_SIGNATURE:
+        case SD_BUS_TYPE_VARIANT:
+                return 1;
+
+        case SD_BUS_TYPE_INT16:
+        case SD_BUS_TYPE_UINT16:
+                return 2;
+
+        case SD_BUS_TYPE_BOOLEAN:
+        case SD_BUS_TYPE_INT32:
+        case SD_BUS_TYPE_UINT32:
+        case SD_BUS_TYPE_STRING:
+        case SD_BUS_TYPE_OBJECT_PATH:
+        case SD_BUS_TYPE_ARRAY:
+        case SD_BUS_TYPE_UNIX_FD:
+                return 4;
+
+        case SD_BUS_TYPE_INT64:
+        case SD_BUS_TYPE_UINT64:
+        case SD_BUS_TYPE_DOUBLE:
+        case SD_BUS_TYPE_STRUCT:
+        case SD_BUS_TYPE_STRUCT_BEGIN:
+        case SD_BUS_TYPE_DICT_ENTRY:
+        case SD_BUS_TYPE_DICT_ENTRY_BEGIN:
+                return 8;
+        }
+
+        return -EINVAL;
+}
+
+int bus_type_get_size(char c) {
+
+        switch (c) {
+        case SD_BUS_TYPE_BYTE:
+                return 1;
+
+        case SD_BUS_TYPE_INT16:
+        case SD_BUS_TYPE_UINT16:
+                return 2;
+
+        case SD_BUS_TYPE_BOOLEAN:
+        case SD_BUS_TYPE_INT32:
+        case SD_BUS_TYPE_UINT32:
+        case SD_BUS_TYPE_UNIX_FD:
+                return 4;
+
+        case SD_BUS_TYPE_INT64:
+        case SD_BUS_TYPE_UINT64:
+        case SD_BUS_TYPE_DOUBLE:
+                return 8;
+        }
+
+        return -EINVAL;
+}
+
+_public_ int sd_bus_interface_name_is_valid(const char *p) {
+        assert_return(p, -EINVAL);
+
+        return interface_name_is_valid(p);
+}
+
+_public_ int sd_bus_service_name_is_valid(const char *p) {
+        assert_return(p, -EINVAL);
+
+        return service_name_is_valid(p);
+}
+
+_public_ int sd_bus_member_name_is_valid(const char *p) {
+        assert_return(p, -EINVAL);
+
+        return member_name_is_valid(p);
+}
+
+_public_ int sd_bus_object_path_is_valid(const char *p) {
+        assert_return(p, -EINVAL);
+
+        return object_path_is_valid(p);
+}
diff --git a/src/libsystemd/sd-bus/bus-type.h b/src/libsystemd/sd-bus/bus-type.h
new file mode 100644
index 0000000..490108a
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-type.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+#include "macro.h"
+
+bool bus_type_is_valid(char c) _const_;
+bool bus_type_is_basic(char c) _const_;
+/* "trivial" is systemd's term for what the D-Bus Specification calls
+ * a "fixed type": that is, a basic type of fixed length */
+bool bus_type_is_trivial(char c) _const_;
+bool bus_type_is_container(char c) _const_;
+
+int bus_type_get_alignment(char c) _const_;
+int bus_type_get_size(char c) _const_;
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
new file mode 100644
index 0000000..b8d4dc8
--- /dev/null
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -0,0 +1,4252 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <endian.h>
+#include <netdb.h>
+#include <poll.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-container.h"
+#include "bus-control.h"
+#include "bus-internal.h"
+#include "bus-kernel.h"
+#include "bus-label.h"
+#include "bus-message.h"
+#include "bus-objects.h"
+#include "bus-protocol.h"
+#include "bus-slot.h"
+#include "bus-socket.h"
+#include "bus-track.h"
+#include "bus-type.h"
+#include "bus-util.h"
+#include "cgroup-util.h"
+#include "def.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "hexdecoct.h"
+#include "hostname-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "missing_syscall.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+#define log_debug_bus_message(m)                                         \
+        do {                                                             \
+                sd_bus_message *_mm = (m);                               \
+                log_debug("Got message type=%s sender=%s destination=%s path=%s interface=%s member=%s cookie=%" PRIu64 " reply_cookie=%" PRIu64 " signature=%s error-name=%s error-message=%s", \
+                          bus_message_type_to_string(_mm->header->type), \
+                          strna(sd_bus_message_get_sender(_mm)),         \
+                          strna(sd_bus_message_get_destination(_mm)),    \
+                          strna(sd_bus_message_get_path(_mm)),           \
+                          strna(sd_bus_message_get_interface(_mm)),      \
+                          strna(sd_bus_message_get_member(_mm)),         \
+                          BUS_MESSAGE_COOKIE(_mm),                       \
+                          _mm->reply_cookie,                             \
+                          strna(_mm->root_container.signature),          \
+                          strna(_mm->error.name),                        \
+                          strna(_mm->error.message));                    \
+        } while (false)
+
+static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec);
+static void bus_detach_io_events(sd_bus *b);
+static void bus_detach_inotify_event(sd_bus *b);
+
+static thread_local sd_bus *default_system_bus = NULL;
+static thread_local sd_bus *default_user_bus = NULL;
+static thread_local sd_bus *default_starter_bus = NULL;
+
+static sd_bus **bus_choose_default(int (**bus_open)(sd_bus **)) {
+        const char *e;
+
+        /* Let's try our best to reuse another cached connection. If
+         * the starter bus type is set, connect via our normal
+         * connection logic, ignoring $DBUS_STARTER_ADDRESS, so that
+         * we can share the connection with the user/system default
+         * bus. */
+
+        e = secure_getenv("DBUS_STARTER_BUS_TYPE");
+        if (e) {
+                if (streq(e, "system")) {
+                        if (bus_open)
+                                *bus_open = sd_bus_open_system;
+                        return &default_system_bus;
+                } else if (STR_IN_SET(e, "user", "session")) {
+                        if (bus_open)
+                                *bus_open = sd_bus_open_user;
+                        return &default_user_bus;
+                }
+        }
+
+        /* No type is specified, so we have not other option than to
+         * use the starter address if it is set. */
+        e = secure_getenv("DBUS_STARTER_ADDRESS");
+        if (e) {
+                if (bus_open)
+                        *bus_open = sd_bus_open;
+                return &default_starter_bus;
+        }
+
+        /* Finally, if nothing is set use the cached connection for
+         * the right scope */
+
+        if (cg_pid_get_owner_uid(0, NULL) >= 0) {
+                if (bus_open)
+                        *bus_open = sd_bus_open_user;
+                return &default_user_bus;
+        } else {
+                if (bus_open)
+                        *bus_open = sd_bus_open_system;
+                return &default_system_bus;
+        }
+}
+
+sd_bus *bus_resolve(sd_bus *bus) {
+        switch ((uintptr_t) bus) {
+        case (uintptr_t) SD_BUS_DEFAULT:
+                return *(bus_choose_default(NULL));
+        case (uintptr_t) SD_BUS_DEFAULT_USER:
+                return default_user_bus;
+        case (uintptr_t) SD_BUS_DEFAULT_SYSTEM:
+                return default_system_bus;
+        default:
+                return bus;
+        }
+}
+
+void bus_close_io_fds(sd_bus *b) {
+        assert(b);
+
+        bus_detach_io_events(b);
+
+        if (b->input_fd != b->output_fd)
+                safe_close(b->output_fd);
+        b->output_fd = b->input_fd = safe_close(b->input_fd);
+}
+
+void bus_close_inotify_fd(sd_bus *b) {
+        assert(b);
+
+        bus_detach_inotify_event(b);
+
+        b->inotify_fd = safe_close(b->inotify_fd);
+        b->inotify_watches = mfree(b->inotify_watches);
+        b->n_inotify_watches = 0;
+}
+
+static void bus_reset_queues(sd_bus *b) {
+        assert(b);
+
+        while (b->rqueue_size > 0)
+                bus_message_unref_queued(b->rqueue[--b->rqueue_size], b);
+
+        b->rqueue = mfree(b->rqueue);
+        b->rqueue_allocated = 0;
+
+        while (b->wqueue_size > 0)
+                bus_message_unref_queued(b->wqueue[--b->wqueue_size], b);
+
+        b->wqueue = mfree(b->wqueue);
+        b->wqueue_allocated = 0;
+}
+
+static sd_bus* bus_free(sd_bus *b) {
+        sd_bus_slot *s;
+
+        assert(b);
+        assert(!b->track_queue);
+        assert(!b->tracks);
+
+        b->state = BUS_CLOSED;
+
+        sd_bus_detach_event(b);
+
+        while ((s = b->slots)) {
+                /* At this point only floating slots can still be
+                 * around, because the non-floating ones keep a
+                 * reference to the bus, and we thus couldn't be
+                 * destructing right now... We forcibly disconnect the
+                 * slots here, so that they still can be referenced by
+                 * apps, but are dead. */
+
+                assert(s->floating);
+                bus_slot_disconnect(s, true);
+        }
+
+        if (b->default_bus_ptr)
+                *b->default_bus_ptr = NULL;
+
+        bus_close_io_fds(b);
+        bus_close_inotify_fd(b);
+
+        free(b->label);
+        free(b->groups);
+        free(b->rbuffer);
+        free(b->unique_name);
+        free(b->auth_buffer);
+        free(b->address);
+        free(b->machine);
+        free(b->description);
+        free(b->patch_sender);
+
+        free(b->exec_path);
+        strv_free(b->exec_argv);
+
+        close_many(b->fds, b->n_fds);
+        free(b->fds);
+
+        bus_reset_queues(b);
+
+        ordered_hashmap_free_free(b->reply_callbacks);
+        prioq_free(b->reply_callbacks_prioq);
+
+        assert(b->match_callbacks.type == BUS_MATCH_ROOT);
+        bus_match_free(&b->match_callbacks);
+
+        hashmap_free_free(b->vtable_methods);
+        hashmap_free_free(b->vtable_properties);
+
+        assert(hashmap_isempty(b->nodes));
+        hashmap_free(b->nodes);
+
+        bus_flush_memfd(b);
+
+        assert_se(pthread_mutex_destroy(&b->memfd_cache_mutex) == 0);
+
+        return mfree(b);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(sd_bus*, bus_free);
+
+_public_ int sd_bus_new(sd_bus **ret) {
+        _cleanup_free_ sd_bus *b = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        b = new(sd_bus, 1);
+        if (!b)
+                return -ENOMEM;
+
+        *b = (sd_bus) {
+                .n_ref = 1,
+                .input_fd = -1,
+                .output_fd = -1,
+                .inotify_fd = -1,
+                .message_version = 1,
+                .creds_mask = SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME,
+                .accept_fd = true,
+                .original_pid = getpid_cached(),
+                .n_groups = (size_t) -1,
+                .close_on_exit = true,
+        };
+
+        /* We guarantee that wqueue always has space for at least one entry */
+        if (!GREEDY_REALLOC(b->wqueue, b->wqueue_allocated, 1))
+                return -ENOMEM;
+
+        assert_se(pthread_mutex_init(&b->memfd_cache_mutex, NULL) == 0);
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_set_address(sd_bus *bus, const char *address) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(address, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return free_and_strdup(&bus->address, address);
+}
+
+_public_ int sd_bus_set_fd(sd_bus *bus, int input_fd, int output_fd) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(input_fd >= 0, -EBADF);
+        assert_return(output_fd >= 0, -EBADF);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->input_fd = input_fd;
+        bus->output_fd = output_fd;
+        return 0;
+}
+
+_public_ int sd_bus_set_exec(sd_bus *bus, const char *path, char *const *argv) {
+        _cleanup_strv_free_ char **a = NULL;
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(path, -EINVAL);
+        assert_return(!strv_isempty(argv), -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        a = strv_copy(argv);
+        if (!a)
+                return -ENOMEM;
+
+        r = free_and_strdup(&bus->exec_path, path);
+        if (r < 0)
+                return r;
+
+        return strv_free_and_replace(bus->exec_argv, a);
+}
+
+_public_ int sd_bus_set_bus_client(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus->patch_sender, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->bus_client = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_set_monitor(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->is_monitor = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_fds(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->accept_fd = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_timestamp(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!IN_SET(bus->state, BUS_CLOSING, BUS_CLOSED), -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        /* This is not actually supported by any of our transports these days, but we do honour it for synthetic
+         * replies, and maybe one day classic D-Bus learns this too */
+        bus->attach_timestamp = !!b;
+
+        return 0;
+}
+
+_public_ int sd_bus_negotiate_creds(sd_bus *bus, int b, uint64_t mask) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(mask <= _SD_BUS_CREDS_ALL, -EINVAL);
+        assert_return(!IN_SET(bus->state, BUS_CLOSING, BUS_CLOSED), -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        SET_FLAG(bus->creds_mask, mask, b);
+
+        /* The well knowns we need unconditionally, so that matches can work */
+        bus->creds_mask |= SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME;
+
+        return 0;
+}
+
+_public_ int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t server_id) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(b || sd_id128_equal(server_id, SD_ID128_NULL), -EINVAL);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->is_server = !!b;
+        bus->server_id = server_id;
+        return 0;
+}
+
+_public_ int sd_bus_set_anonymous(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->anonymous_auth = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_set_trusted(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->trusted = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_set_description(sd_bus *bus, const char *description) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return free_and_strdup(&bus->description, description);
+}
+
+_public_ int sd_bus_set_allow_interactive_authorization(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->allow_interactive_authorization = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_get_allow_interactive_authorization(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->allow_interactive_authorization;
+}
+
+_public_ int sd_bus_set_watch_bind(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->watch_bind = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_get_watch_bind(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->watch_bind;
+}
+
+_public_ int sd_bus_set_connected_signal(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus->connected_signal = !!b;
+        return 0;
+}
+
+_public_ int sd_bus_get_connected_signal(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->connected_signal;
+}
+
+static int synthesize_connected_signal(sd_bus *bus) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+
+        /* If enabled, synthesizes a local "Connected" signal mirroring the local "Disconnected" signal. This is called
+         * whenever we fully established a connection, i.e. after the authorization phase, and after receiving the
+         * Hello() reply. Or in other words, whenever we enter BUS_RUNNING state.
+         *
+         * This is useful so that clients can start doing stuff whenever the connection is fully established in a way
+         * that works independently from whether we connected to a full bus or just a direct connection. */
+
+        if (!bus->connected_signal)
+                return 0;
+
+        r = sd_bus_message_new_signal(
+                        bus,
+                        &m,
+                        "/org/freedesktop/DBus/Local",
+                        "org.freedesktop.DBus.Local",
+                        "Connected");
+        if (r < 0)
+                return r;
+
+        bus_message_set_sender_local(bus, m);
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
+        /* Insert at the very front */
+        memmove(bus->rqueue + 1, bus->rqueue, sizeof(sd_bus_message*) * bus->rqueue_size);
+        bus->rqueue[0] = bus_message_ref_queued(m, bus);
+        bus->rqueue_size++;
+
+        return 0;
+}
+
+void bus_set_state(sd_bus *bus, enum bus_state state) {
+        static const char * const table[_BUS_STATE_MAX] = {
+                [BUS_UNSET] = "UNSET",
+                [BUS_WATCH_BIND] = "WATCH_BIND",
+                [BUS_OPENING] = "OPENING",
+                [BUS_AUTHENTICATING] = "AUTHENTICATING",
+                [BUS_HELLO] = "HELLO",
+                [BUS_RUNNING] = "RUNNING",
+                [BUS_CLOSING] = "CLOSING",
+                [BUS_CLOSED] = "CLOSED",
+        };
+
+        assert(bus);
+        assert(state < _BUS_STATE_MAX);
+
+        if (state == bus->state)
+                return;
+
+        log_debug("Bus %s: changing state %s → %s", strna(bus->description), table[bus->state], table[state]);
+        bus->state = state;
+}
+
+static int hello_callback(sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+        const char *s;
+        sd_bus *bus;
+        int r;
+
+        assert(reply);
+        bus = reply->bus;
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_HELLO, BUS_CLOSING));
+
+        r = sd_bus_message_get_errno(reply);
+        if (r > 0) {
+                r = -r;
+                goto fail;
+        }
+
+        r = sd_bus_message_read(reply, "s", &s);
+        if (r < 0)
+                goto fail;
+
+        if (!service_name_is_valid(s) || s[0] != ':') {
+                r = -EBADMSG;
+                goto fail;
+        }
+
+        r = free_and_strdup(&bus->unique_name, s);
+        if (r < 0)
+                goto fail;
+
+        if (bus->state == BUS_HELLO) {
+                bus_set_state(bus, BUS_RUNNING);
+
+                r = synthesize_connected_signal(bus);
+                if (r < 0)
+                        goto fail;
+        }
+
+        return 1;
+
+fail:
+        /* When Hello() failed, let's propagate this in two ways: first we return the error immediately here,
+         * which is the propagated up towards the event loop. Let's also invalidate the connection, so that
+         * if the user then calls back into us again we won't wait any longer. */
+
+        bus_set_state(bus, BUS_CLOSING);
+        return r;
+}
+
+static int bus_send_hello(sd_bus *bus) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+
+        if (!bus->bus_client)
+                return 0;
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.DBus",
+                        "/org/freedesktop/DBus",
+                        "org.freedesktop.DBus",
+                        "Hello");
+        if (r < 0)
+                return r;
+
+        return sd_bus_call_async(bus, NULL, m, hello_callback, NULL, 0);
+}
+
+int bus_start_running(sd_bus *bus) {
+        struct reply_callback *c;
+        usec_t n;
+        int r;
+
+        assert(bus);
+        assert(bus->state < BUS_HELLO);
+
+        /* We start all method call timeouts when we enter BUS_HELLO or BUS_RUNNING mode. At this point let's convert
+         * all relative to absolute timestamps. Note that we do not reshuffle the reply callback priority queue since
+         * adding a fixed value to all entries should not alter the internal order. */
+
+        n = now(CLOCK_MONOTONIC);
+        ORDERED_HASHMAP_FOREACH(c, bus->reply_callbacks) {
+                if (c->timeout_usec == 0)
+                        continue;
+
+                c->timeout_usec = usec_add(n, c->timeout_usec);
+        }
+
+        if (bus->bus_client) {
+                bus_set_state(bus, BUS_HELLO);
+                return 1;
+        }
+
+        bus_set_state(bus, BUS_RUNNING);
+
+        r = synthesize_connected_signal(bus);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int parse_address_key(const char **p, const char *key, char **value) {
+        size_t l, n = 0, allocated = 0;
+        _cleanup_free_ char *r = NULL;
+        const char *a;
+
+        assert(p);
+        assert(*p);
+        assert(value);
+
+        if (key) {
+                l = strlen(key);
+                if (strncmp(*p, key, l) != 0)
+                        return 0;
+
+                if ((*p)[l] != '=')
+                        return 0;
+
+                if (*value)
+                        return -EINVAL;
+
+                a = *p + l + 1;
+        } else
+                a = *p;
+
+        while (!IN_SET(*a, ';', ',', 0)) {
+                char c;
+
+                if (*a == '%') {
+                        int x, y;
+
+                        x = unhexchar(a[1]);
+                        if (x < 0)
+                                return x;
+
+                        y = unhexchar(a[2]);
+                        if (y < 0)
+                                return y;
+
+                        c = (char) ((x << 4) | y);
+                        a += 3;
+                } else {
+                        c = *a;
+                        a++;
+                }
+
+                if (!GREEDY_REALLOC(r, allocated, n + 2))
+                        return -ENOMEM;
+
+                r[n++] = c;
+        }
+
+        if (!r) {
+                r = strdup("");
+                if (!r)
+                        return -ENOMEM;
+        } else
+                r[n] = 0;
+
+        if (*a == ',')
+                a++;
+
+        *p = a;
+
+        free_and_replace(*value, r);
+
+        return 1;
+}
+
+static void skip_address_key(const char **p) {
+        assert(p);
+        assert(*p);
+
+        *p += strcspn(*p, ",");
+
+        if (**p == ',')
+                (*p)++;
+}
+
+static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *path = NULL, *abstract = NULL;
+        size_t l;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "abstract", &abstract);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                skip_address_key(p);
+        }
+
+        if (!path && !abstract)
+                return -EINVAL;
+
+        if (path && abstract)
+                return -EINVAL;
+
+        if (path) {
+                l = strlen(path);
+                if (l >= sizeof(b->sockaddr.un.sun_path)) /* We insist on NUL termination */
+                        return -E2BIG;
+
+                b->sockaddr.un = (struct sockaddr_un) {
+                        .sun_family = AF_UNIX,
+                };
+
+                memcpy(b->sockaddr.un.sun_path, path, l);
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + l + 1;
+
+        } else {
+                assert(abstract);
+
+                l = strlen(abstract);
+                if (l >= sizeof(b->sockaddr.un.sun_path) - 1) /* We insist on NUL termination */
+                        return -E2BIG;
+
+                b->sockaddr.un = (struct sockaddr_un) {
+                        .sun_family = AF_UNIX,
+                };
+
+                memcpy(b->sockaddr.un.sun_path+1, abstract, l);
+                b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
+        }
+
+        b->is_local = true;
+
+        return 0;
+}
+
+static int parse_tcp_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *host = NULL, *port = NULL, *family = NULL;
+        int r;
+        struct addrinfo *result, hints = {
+                .ai_socktype = SOCK_STREAM,
+        };
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "host", &host);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "port", &port);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "family", &family);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                skip_address_key(p);
+        }
+
+        if (!host || !port)
+                return -EINVAL;
+
+        if (family) {
+                if (streq(family, "ipv4"))
+                        hints.ai_family = AF_INET;
+                else if (streq(family, "ipv6"))
+                        hints.ai_family = AF_INET6;
+                else
+                        return -EINVAL;
+        }
+
+        r = getaddrinfo(host, port, &hints, &result);
+        if (r == EAI_SYSTEM)
+                return -errno;
+        else if (r != 0)
+                return -EADDRNOTAVAIL;
+
+        memcpy(&b->sockaddr, result->ai_addr, result->ai_addrlen);
+        b->sockaddr_size = result->ai_addrlen;
+
+        freeaddrinfo(result);
+
+        b->is_local = false;
+
+        return 0;
+}
+
+static int parse_exec_address(sd_bus *b, const char **p, char **guid) {
+        char *path = NULL;
+        unsigned n_argv = 0, j;
+        char **argv = NULL;
+        size_t allocated = 0;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        goto fail;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "path", &path);
+                if (r < 0)
+                        goto fail;
+                else if (r > 0)
+                        continue;
+
+                if (startswith(*p, "argv")) {
+                        unsigned ul;
+
+                        errno = 0;
+                        ul = strtoul(*p + 4, (char**) p, 10);
+                        if (errno > 0 || **p != '=' || ul > 256) {
+                                r = -EINVAL;
+                                goto fail;
+                        }
+
+                        (*p)++;
+
+                        if (ul >= n_argv) {
+                                if (!GREEDY_REALLOC0(argv, allocated, ul + 2)) {
+                                        r = -ENOMEM;
+                                        goto fail;
+                                }
+
+                                n_argv = ul + 1;
+                        }
+
+                        r = parse_address_key(p, NULL, argv + ul);
+                        if (r < 0)
+                                goto fail;
+
+                        continue;
+                }
+
+                skip_address_key(p);
+        }
+
+        if (!path) {
+                r = -EINVAL;
+                goto fail;
+        }
+
+        /* Make sure there are no holes in the array, with the
+         * exception of argv[0] */
+        for (j = 1; j < n_argv; j++)
+                if (!argv[j]) {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+        if (argv && argv[0] == NULL) {
+                argv[0] = strdup(path);
+                if (!argv[0]) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        b->exec_path = path;
+        b->exec_argv = argv;
+
+        b->is_local = false;
+
+        return 0;
+
+fail:
+        for (j = 0; j < n_argv; j++)
+                free(argv[j]);
+
+        free(argv);
+        free(path);
+        return r;
+}
+
+static int parse_container_unix_address(sd_bus *b, const char **p, char **guid) {
+        _cleanup_free_ char *machine = NULL, *pid = NULL;
+        int r;
+
+        assert(b);
+        assert(p);
+        assert(*p);
+        assert(guid);
+
+        while (!IN_SET(**p, 0, ';')) {
+                r = parse_address_key(p, "guid", guid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "machine", &machine);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "pid", &pid);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                skip_address_key(p);
+        }
+
+        if (!machine == !pid)
+                return -EINVAL;
+
+        if (machine) {
+                if (!streq(machine, ".host") && !machine_name_is_valid(machine))
+                        return -EINVAL;
+
+                free_and_replace(b->machine, machine);
+        } else
+                b->machine = mfree(b->machine);
+
+        if (pid) {
+                r = parse_pid(pid, &b->nspid);
+                if (r < 0)
+                        return r;
+        } else
+                b->nspid = 0;
+
+        b->sockaddr.un = (struct sockaddr_un) {
+                .sun_family = AF_UNIX,
+                /* Note that we use the old /var/run prefix here, to increase compatibility with really old containers */
+                .sun_path = "/var/run/dbus/system_bus_socket",
+        };
+        b->sockaddr_size = SOCKADDR_UN_LEN(b->sockaddr.un);
+        b->is_local = false;
+
+        return 0;
+}
+
+static void bus_reset_parsed_address(sd_bus *b) {
+        assert(b);
+
+        zero(b->sockaddr);
+        b->sockaddr_size = 0;
+        b->exec_argv = strv_free(b->exec_argv);
+        b->exec_path = mfree(b->exec_path);
+        b->server_id = SD_ID128_NULL;
+        b->machine = mfree(b->machine);
+        b->nspid = 0;
+}
+
+static int bus_parse_next_address(sd_bus *b) {
+        _cleanup_free_ char *guid = NULL;
+        const char *a;
+        int r;
+
+        assert(b);
+
+        if (!b->address)
+                return 0;
+        if (b->address[b->address_index] == 0)
+                return 0;
+
+        bus_reset_parsed_address(b);
+
+        a = b->address + b->address_index;
+
+        while (*a != 0) {
+
+                if (*a == ';') {
+                        a++;
+                        continue;
+                }
+
+                if (startswith(a, "unix:")) {
+                        a += 5;
+
+                        r = parse_unix_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+                        break;
+
+                } else if (startswith(a, "tcp:")) {
+
+                        a += 4;
+                        r = parse_tcp_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                } else if (startswith(a, "unixexec:")) {
+
+                        a += 9;
+                        r = parse_exec_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+
+                } else if (startswith(a, "x-machine-unix:")) {
+
+                        a += 15;
+                        r = parse_container_unix_address(b, &a, &guid);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                }
+
+                a = strchr(a, ';');
+                if (!a)
+                        return 0;
+        }
+
+        if (guid) {
+                r = sd_id128_from_string(guid, &b->server_id);
+                if (r < 0)
+                        return r;
+        }
+
+        b->address_index = a - b->address;
+        return 1;
+}
+
+static void bus_kill_exec(sd_bus *bus) {
+        if (pid_is_valid(bus->busexec_pid) > 0) {
+                sigterm_wait(bus->busexec_pid);
+                bus->busexec_pid = 0;
+        }
+}
+
+static int bus_start_address(sd_bus *b) {
+        int r;
+
+        assert(b);
+
+        for (;;) {
+                bus_close_io_fds(b);
+                bus_close_inotify_fd(b);
+
+                bus_kill_exec(b);
+
+                /* If you provide multiple different bus-addresses, we
+                 * try all of them in order and use the first one that
+                 * succeeds. */
+
+                if (b->exec_path)
+                        r = bus_socket_exec(b);
+                else if ((b->nspid > 0 || b->machine) && b->sockaddr.sa.sa_family != AF_UNSPEC)
+                        r = bus_container_connect_socket(b);
+                else if (b->sockaddr.sa.sa_family != AF_UNSPEC)
+                        r = bus_socket_connect(b);
+                else
+                        goto next;
+
+                if (r >= 0) {
+                        int q;
+
+                        q = bus_attach_io_events(b);
+                        if (q < 0)
+                                return q;
+
+                        q = bus_attach_inotify_event(b);
+                        if (q < 0)
+                                return q;
+
+                        return r;
+                }
+
+                b->last_connect_error = -r;
+
+        next:
+                r = bus_parse_next_address(b);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return b->last_connect_error > 0 ? -b->last_connect_error : -ECONNREFUSED;
+        }
+}
+
+int bus_next_address(sd_bus *b) {
+        assert(b);
+
+        bus_reset_parsed_address(b);
+        return bus_start_address(b);
+}
+
+static int bus_start_fd(sd_bus *b) {
+        struct stat st;
+        int r;
+
+        assert(b);
+        assert(b->input_fd >= 0);
+        assert(b->output_fd >= 0);
+
+        if (DEBUG_LOGGING) {
+                _cleanup_free_ char *pi = NULL, *po = NULL;
+                (void) fd_get_path(b->input_fd, &pi);
+                (void) fd_get_path(b->output_fd, &po);
+                log_debug("sd-bus: starting bus%s%s on fds %d/%d (%s, %s)...",
+                          b->description ? " " : "", strempty(b->description),
+                          b->input_fd, b->output_fd,
+                          pi ?: "???", po ?: "???");
+        }
+
+        r = fd_nonblock(b->input_fd, true);
+        if (r < 0)
+                return r;
+
+        r = fd_cloexec(b->input_fd, true);
+        if (r < 0)
+                return r;
+
+        if (b->input_fd != b->output_fd) {
+                r = fd_nonblock(b->output_fd, true);
+                if (r < 0)
+                        return r;
+
+                r = fd_cloexec(b->output_fd, true);
+                if (r < 0)
+                        return r;
+        }
+
+        if (fstat(b->input_fd, &st) < 0)
+                return -errno;
+
+        return bus_socket_take_fd(b);
+}
+
+_public_ int sd_bus_start(sd_bus *bus) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state == BUS_UNSET, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        bus_set_state(bus, BUS_OPENING);
+
+        if (bus->is_server && bus->bus_client)
+                return -EINVAL;
+
+        if (bus->input_fd >= 0)
+                r = bus_start_fd(bus);
+        else if (bus->address || bus->sockaddr.sa.sa_family != AF_UNSPEC || bus->exec_path || bus->machine)
+                r = bus_start_address(bus);
+        else
+                return -EINVAL;
+
+        if (r < 0) {
+                sd_bus_close(bus);
+                return r;
+        }
+
+        return bus_send_hello(bus);
+}
+
+_public_ int sd_bus_open_with_description(sd_bus **ret, const char *description) {
+        const char *e;
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        /* Let's connect to the starter bus if it is set, and
+         * otherwise to the bus that is appropriate for the scope
+         * we are running in */
+
+        e = secure_getenv("DBUS_STARTER_BUS_TYPE");
+        if (e) {
+                if (streq(e, "system"))
+                        return sd_bus_open_system_with_description(ret, description);
+                else if (STR_IN_SET(e, "session", "user"))
+                        return sd_bus_open_user_with_description(ret, description);
+        }
+
+        e = secure_getenv("DBUS_STARTER_ADDRESS");
+        if (!e) {
+                if (cg_pid_get_owner_uid(0, NULL) >= 0)
+                        return sd_bus_open_user_with_description(ret, description);
+                else
+                        return sd_bus_open_system_with_description(ret, description);
+        }
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_set_address(b, e);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+
+        /* We don't know whether the bus is trusted or not, so better
+         * be safe, and authenticate everything */
+        b->trusted = false;
+        b->is_local = false;
+        b->creds_mask |= SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_EFFECTIVE_CAPS;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open(sd_bus **ret) {
+        return sd_bus_open_with_description(ret, NULL);
+}
+
+int bus_set_address_system(sd_bus *b) {
+        const char *e;
+        int r;
+
+        assert(b);
+
+        e = secure_getenv("DBUS_SYSTEM_BUS_ADDRESS");
+
+        r = sd_bus_set_address(b, e ?: DEFAULT_SYSTEM_BUS_ADDRESS);
+        if (r >= 0)
+                b->is_system = true;
+        return r;
+}
+
+_public_ int sd_bus_open_system_with_description(sd_bus **ret, const char *description) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        if (description) {
+                r = sd_bus_set_description(b, description);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bus_set_address_system(b);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+
+        /* Let's do per-method access control on the system bus. We
+         * need the caller's UID and capability set for that. */
+        b->trusted = false;
+        b->creds_mask |= SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_EFFECTIVE_CAPS;
+        b->is_local = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open_system(sd_bus **ret) {
+        return sd_bus_open_system_with_description(ret, NULL);
+}
+
+int bus_set_address_user(sd_bus *b) {
+        const char *a;
+        _cleanup_free_ char *_a = NULL;
+        int r;
+
+        assert(b);
+
+        a = secure_getenv("DBUS_SESSION_BUS_ADDRESS");
+        if (!a) {
+                const char *e;
+                _cleanup_free_ char *ee = NULL;
+
+                e = secure_getenv("XDG_RUNTIME_DIR");
+                if (!e)
+                        return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
+                                               "sd-bus: $XDG_RUNTIME_DIR not set, cannot connect to user bus.");
+
+                ee = bus_address_escape(e);
+                if (!ee)
+                        return -ENOMEM;
+
+                if (asprintf(&_a, DEFAULT_USER_BUS_ADDRESS_FMT, ee) < 0)
+                        return -ENOMEM;
+                a = _a;
+        }
+
+        r = sd_bus_set_address(b, a);
+        if (r >= 0)
+                b->is_user = true;
+        return r;
+}
+
+_public_ int sd_bus_open_user_with_description(sd_bus **ret, const char *description) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        if (description) {
+                r = sd_bus_set_description(b, description);
+                if (r < 0)
+                        return r;
+        }
+
+        r = bus_set_address_user(b);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+
+        /* We don't do any per-method access control on the user bus. */
+        b->trusted = true;
+        b->is_local = true;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ int sd_bus_open_user(sd_bus **ret) {
+        return sd_bus_open_user_with_description(ret, NULL);
+}
+
+int bus_set_address_system_remote(sd_bus *b, const char *host) {
+        _cleanup_free_ char *e = NULL;
+        char *m = NULL, *c = NULL, *a, *rbracket = NULL, *p = NULL;
+
+        assert(b);
+        assert(host);
+
+        /* Skip ":"s in ipv6 addresses */
+        if (*host == '[') {
+                char *t;
+
+                rbracket = strchr(host, ']');
+                if (!rbracket)
+                        return -EINVAL;
+                t = strndupa(host + 1, rbracket - host - 1);
+                e = bus_address_escape(t);
+                if (!e)
+                        return -ENOMEM;
+        } else if ((a = strchr(host, '@'))) {
+                if (*(a + 1) == '[') {
+                        _cleanup_free_ char *t = NULL;
+
+                        rbracket = strchr(a + 1, ']');
+                        if (!rbracket)
+                                return -EINVAL;
+                        t = new0(char, strlen(host));
+                        if (!t)
+                                return -ENOMEM;
+                        strncat(t, host, a - host + 1);
+                        strncat(t, a + 2, rbracket - a - 2);
+                        e = bus_address_escape(t);
+                        if (!e)
+                                return -ENOMEM;
+                } else if (*(a + 1) == '\0' || strchr(a + 1, '@'))
+                        return -EINVAL;
+        }
+
+        /* Let's see if a port was given */
+        m = strchr(rbracket ? rbracket + 1 : host, ':');
+        if (m) {
+                char *t;
+                bool got_forward_slash = false;
+
+                p = m + 1;
+
+                t = strchr(p, '/');
+                if (t) {
+                        p = strndupa(p, t - p);
+                        got_forward_slash = true;
+                }
+
+                if (!in_charset(p, "0123456789") || *p == '\0') {
+                        if (!machine_name_is_valid(p) || got_forward_slash)
+                                return -EINVAL;
+
+                        m = TAKE_PTR(p);
+                        goto interpret_port_as_machine_old_syntax;
+                }
+        }
+
+        /* Let's see if a machine was given */
+        m = strchr(rbracket ? rbracket + 1 : host, '/');
+        if (m) {
+                m++;
+interpret_port_as_machine_old_syntax:
+                /* Let's make sure this is not a port of some kind,
+                 * and is a valid machine name. */
+                if (!in_charset(m, "0123456789") && machine_name_is_valid(m))
+                        c = strjoina(",argv", p ? "7" : "5", "=--machine=", m);
+        }
+
+        if (!e) {
+                char *t;
+
+                t = strndupa(host, strcspn(host, ":/"));
+
+                e = bus_address_escape(t);
+                if (!e)
+                        return -ENOMEM;
+        }
+
+        a = strjoin("unixexec:path=ssh,argv1=-xT", p ? ",argv2=-p,argv3=" : "", strempty(p),
+                                ",argv", p ? "4" : "2", "=--,argv", p ? "5" : "3", "=", e,
+                                ",argv", p ? "6" : "4", "=systemd-stdio-bridge", c);
+        if (!a)
+                return -ENOMEM;
+
+        return free_and_replace(b->address, a);
+}
+
+_public_ int sd_bus_open_system_remote(sd_bus **ret, const char *host) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(host, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = bus_set_address_system_remote(b, host);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+        b->trusted = false;
+        b->is_system = true;
+        b->is_local = false;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+int bus_set_address_system_machine(sd_bus *b, const char *machine) {
+        _cleanup_free_ char *e = NULL;
+        char *a;
+
+        assert(b);
+        assert(machine);
+
+        e = bus_address_escape(machine);
+        if (!e)
+                return -ENOMEM;
+
+        a = strjoin("x-machine-unix:machine=", e);
+        if (!a)
+                return -ENOMEM;
+
+        return free_and_replace(b->address, a);
+}
+
+_public_ int sd_bus_open_system_machine(sd_bus **ret, const char *machine) {
+        _cleanup_(bus_freep) sd_bus *b = NULL;
+        int r;
+
+        assert_return(machine, -EINVAL);
+        assert_return(ret, -EINVAL);
+        assert_return(streq(machine, ".host") || machine_name_is_valid(machine), -EINVAL);
+
+        r = sd_bus_new(&b);
+        if (r < 0)
+                return r;
+
+        r = bus_set_address_system_machine(b, machine);
+        if (r < 0)
+                return r;
+
+        b->bus_client = true;
+        b->trusted = false;
+        b->is_system = true;
+        b->is_local = false;
+
+        r = sd_bus_start(b);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(b);
+        return 0;
+}
+
+_public_ void sd_bus_close(sd_bus *bus) {
+        if (!bus)
+                return;
+        if (bus->state == BUS_CLOSED)
+                return;
+        if (bus_pid_changed(bus))
+                return;
+
+        /* Don't leave ssh hanging around */
+        bus_kill_exec(bus);
+
+        bus_set_state(bus, BUS_CLOSED);
+
+        sd_bus_detach_event(bus);
+
+        /* Drop all queued messages so that they drop references to
+         * the bus object and the bus may be freed */
+        bus_reset_queues(bus);
+
+        bus_close_io_fds(bus);
+        bus_close_inotify_fd(bus);
+}
+
+_public_ sd_bus *sd_bus_close_unref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+
+        sd_bus_close(bus);
+
+        return sd_bus_unref(bus);
+}
+
+_public_ sd_bus* sd_bus_flush_close_unref(sd_bus *bus) {
+        if (!bus)
+                return NULL;
+
+        /* Have to do this before flush() to prevent hang */
+        bus_kill_exec(bus);
+        sd_bus_flush(bus);
+
+        return sd_bus_close_unref(bus);
+}
+
+void bus_enter_closing(sd_bus *bus) {
+        assert(bus);
+
+        if (!IN_SET(bus->state, BUS_WATCH_BIND, BUS_OPENING, BUS_AUTHENTICATING, BUS_HELLO, BUS_RUNNING))
+                return;
+
+        bus_set_state(bus, BUS_CLOSING);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_bus, sd_bus, bus_free);
+
+_public_ int sd_bus_is_open(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return BUS_IS_OPEN(bus->state);
+}
+
+_public_ int sd_bus_is_ready(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->state == BUS_RUNNING;
+}
+
+_public_ int sd_bus_can_send(sd_bus *bus, char type) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->state != BUS_UNSET, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (type == SD_BUS_TYPE_UNIX_FD) {
+                if (!bus->accept_fd)
+                        return 0;
+
+                r = bus_ensure_running(bus);
+                if (r < 0)
+                        return r;
+
+                return bus->can_fds;
+        }
+
+        return bus_type_is_valid(type);
+}
+
+_public_ int sd_bus_get_bus_id(sd_bus *bus, sd_id128_t *id) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(id, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        *id = bus->server_id;
+        return 0;
+}
+
+#define COOKIE_CYCLED (UINT32_C(1) << 31)
+
+static uint64_t cookie_inc(uint64_t cookie) {
+
+        /* Stay within the 32bit range, since classic D-Bus can't deal with more */
+        if (cookie >= UINT32_MAX)
+                return COOKIE_CYCLED; /* Don't go back to zero, but use the highest bit for checking
+                                       * whether we are looping. */
+
+        return cookie + 1;
+}
+
+static int next_cookie(sd_bus *b) {
+        uint64_t new_cookie;
+
+        assert(b);
+
+        new_cookie = cookie_inc(b->cookie);
+
+        /* Small optimization: don't bother with checking for cookie reuse until we overran cookiespace at
+         * least once, but then do it thorougly. */
+        if (FLAGS_SET(new_cookie, COOKIE_CYCLED)) {
+                uint32_t i;
+
+                /* Check if the cookie is currently in use. If so, pick the next one */
+                for (i = 0; i < COOKIE_CYCLED; i++) {
+                        if (!ordered_hashmap_contains(b->reply_callbacks, &new_cookie))
+                                goto good;
+
+                        new_cookie = cookie_inc(new_cookie);
+                }
+
+                /* Can't fulfill request */
+                return -EBUSY;
+        }
+
+good:
+        b->cookie = new_cookie;
+        return 0;
+}
+
+static int bus_seal_message(sd_bus *b, sd_bus_message *m, usec_t timeout) {
+        int r;
+
+        assert(b);
+        assert(m);
+
+        if (m->sealed) {
+                /* If we copy the same message to multiple
+                 * destinations, avoid using the same cookie
+                 * numbers. */
+                b->cookie = MAX(b->cookie, BUS_MESSAGE_COOKIE(m));
+                return 0;
+        }
+
+        if (timeout == 0) {
+                r = sd_bus_get_method_call_timeout(b, &timeout);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!m->sender && b->patch_sender) {
+                r = sd_bus_message_set_sender(m, b->patch_sender);
+                if (r < 0)
+                        return r;
+        }
+
+        r = next_cookie(b);
+        if (r < 0)
+                return r;
+
+        return sd_bus_message_seal(m, b->cookie, timeout);
+}
+
+static int bus_remarshal_message(sd_bus *b, sd_bus_message **m) {
+        bool remarshal = false;
+
+        assert(b);
+
+        /* wrong packet version */
+        if (b->message_version != 0 && b->message_version != (*m)->header->version)
+                remarshal = true;
+
+        /* wrong packet endianness */
+        if (b->message_endian != 0 && b->message_endian != (*m)->header->endian)
+                remarshal = true;
+
+        return remarshal ? bus_message_remarshal(b, m) : 0;
+}
+
+int bus_seal_synthetic_message(sd_bus *b, sd_bus_message *m) {
+        assert(b);
+        assert(m);
+
+        /* Fake some timestamps, if they were requested, and not
+         * already initialized */
+        if (b->attach_timestamp) {
+                if (m->realtime <= 0)
+                        m->realtime = now(CLOCK_REALTIME);
+
+                if (m->monotonic <= 0)
+                        m->monotonic = now(CLOCK_MONOTONIC);
+        }
+
+        /* The bus specification says the serial number cannot be 0,
+         * hence let's fill something in for synthetic messages. Since
+         * synthetic messages might have a fake sender and we don't
+         * want to interfere with the real sender's serial numbers we
+         * pick a fixed, artificial one. We use (uint32_t) -1 rather
+         * than (uint64_t) -1 since dbus1 only had 32bit identifiers,
+         * even though kdbus can do 64bit. */
+        return sd_bus_message_seal(m, 0xFFFFFFFFULL, 0);
+}
+
+static int bus_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        r = bus_socket_write_message(bus, m, idx);
+        if (r <= 0)
+                return r;
+
+        if (*idx >= BUS_MESSAGE_SIZE(m))
+                log_debug("Sent message type=%s sender=%s destination=%s path=%s interface=%s member=%s cookie=%" PRIu64 " reply_cookie=%" PRIu64 " signature=%s error-name=%s error-message=%s",
+                          bus_message_type_to_string(m->header->type),
+                          strna(sd_bus_message_get_sender(m)),
+                          strna(sd_bus_message_get_destination(m)),
+                          strna(sd_bus_message_get_path(m)),
+                          strna(sd_bus_message_get_interface(m)),
+                          strna(sd_bus_message_get_member(m)),
+                          BUS_MESSAGE_COOKIE(m),
+                          m->reply_cookie,
+                          strna(m->root_container.signature),
+                          strna(m->error.name),
+                          strna(m->error.message));
+
+        return r;
+}
+
+static int dispatch_wqueue(sd_bus *bus) {
+        int r, ret = 0;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        while (bus->wqueue_size > 0) {
+
+                r = bus_write_message(bus, bus->wqueue[0], &bus->windex);
+                if (r < 0)
+                        return r;
+                else if (r == 0)
+                        /* Didn't do anything this time */
+                        return ret;
+                else if (bus->windex >= BUS_MESSAGE_SIZE(bus->wqueue[0])) {
+                        /* Fully written. Let's drop the entry from
+                         * the queue.
+                         *
+                         * This isn't particularly optimized, but
+                         * well, this is supposed to be our worst-case
+                         * buffer only, and the socket buffer is
+                         * supposed to be our primary buffer, and if
+                         * it got full, then all bets are off
+                         * anyway. */
+
+                        bus->wqueue_size--;
+                        bus_message_unref_queued(bus->wqueue[0], bus);
+                        memmove(bus->wqueue, bus->wqueue + 1, sizeof(sd_bus_message*) * bus->wqueue_size);
+                        bus->windex = 0;
+
+                        ret = 1;
+                }
+        }
+
+        return ret;
+}
+
+static int bus_read_message(sd_bus *bus) {
+        assert(bus);
+
+        return bus_socket_read_message(bus);
+}
+
+int bus_rqueue_make_room(sd_bus *bus) {
+        assert(bus);
+
+        if (bus->rqueue_size >= BUS_RQUEUE_MAX)
+                return -ENOBUFS;
+
+        if (!GREEDY_REALLOC(bus->rqueue, bus->rqueue_allocated, bus->rqueue_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+static void rqueue_drop_one(sd_bus *bus, size_t i) {
+        assert(bus);
+        assert(i < bus->rqueue_size);
+
+        bus_message_unref_queued(bus->rqueue[i], bus);
+        memmove(bus->rqueue + i, bus->rqueue + i + 1, sizeof(sd_bus_message*) * (bus->rqueue_size - i - 1));
+        bus->rqueue_size--;
+}
+
+static int dispatch_rqueue(sd_bus *bus, sd_bus_message **m) {
+        int r, ret = 0;
+
+        assert(bus);
+        assert(m);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        for (;;) {
+                if (bus->rqueue_size > 0) {
+                        /* Dispatch a queued message */
+                        *m = sd_bus_message_ref(bus->rqueue[0]);
+                        rqueue_drop_one(bus, 0);
+                        return 1;
+                }
+
+                /* Try to read a new message */
+                r = bus_read_message(bus);
+                if (r < 0)
+                        return r;
+                if (r == 0) {
+                        *m = NULL;
+                        return ret;
+                }
+
+                ret = 1;
+        }
+}
+
+_public_ int sd_bus_send(sd_bus *bus, sd_bus_message *_m, uint64_t *cookie) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (m->n_fds > 0) {
+                r = sd_bus_can_send(bus, SD_BUS_TYPE_UNIX_FD);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -EOPNOTSUPP;
+        }
+
+        /* If the cookie number isn't kept, then we know that no reply
+         * is expected */
+        if (!cookie && !m->sealed)
+                m->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        r = bus_seal_message(bus, m, 0);
+        if (r < 0)
+                return r;
+
+        /* Remarshall if we have to. This will possibly unref the
+         * message and place a replacement in m */
+        r = bus_remarshal_message(bus, &m);
+        if (r < 0)
+                return r;
+
+        /* If this is a reply and no reply was requested, then let's
+         * suppress this, if we can */
+        if (m->dont_send)
+                goto finish;
+
+        if (IN_SET(bus->state, BUS_RUNNING, BUS_HELLO) && bus->wqueue_size <= 0) {
+                size_t idx = 0;
+
+                r = bus_write_message(bus, m, &idx);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                return -ECONNRESET;
+                        }
+
+                        return r;
+                }
+
+                if (idx < BUS_MESSAGE_SIZE(m))  {
+                        /* Wasn't fully written. So let's remember how
+                         * much was written. Note that the first entry
+                         * of the wqueue array is always allocated so
+                         * that we always can remember how much was
+                         * written. */
+                        bus->wqueue[0] = bus_message_ref_queued(m, bus);
+                        bus->wqueue_size = 1;
+                        bus->windex = idx;
+                }
+
+        } else {
+                /* Just append it to the queue. */
+
+                if (bus->wqueue_size >= BUS_WQUEUE_MAX)
+                        return -ENOBUFS;
+
+                if (!GREEDY_REALLOC(bus->wqueue, bus->wqueue_allocated, bus->wqueue_size + 1))
+                        return -ENOMEM;
+
+                bus->wqueue[bus->wqueue_size++] = bus_message_ref_queued(m, bus);
+        }
+
+finish:
+        if (cookie)
+                *cookie = BUS_MESSAGE_COOKIE(m);
+
+        return 1;
+}
+
+_public_ int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destination, uint64_t *cookie) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (!streq_ptr(m->destination, destination)) {
+
+                if (!destination)
+                        return -EEXIST;
+
+                r = sd_bus_message_set_destination(m, destination);
+                if (r < 0)
+                        return r;
+        }
+
+        return sd_bus_send(bus, m, cookie);
+}
+
+static usec_t calc_elapse(sd_bus *bus, uint64_t usec) {
+        assert(bus);
+
+        if (usec == (uint64_t) -1)
+                return 0;
+
+        /* We start all timeouts the instant we enter BUS_HELLO/BUS_RUNNING state, so that the don't run in parallel
+         * with any connection setup states. Hence, if a method callback is started earlier than that we just store the
+         * relative timestamp, and afterwards the absolute one. */
+
+        if (IN_SET(bus->state, BUS_WATCH_BIND, BUS_OPENING, BUS_AUTHENTICATING))
+                return usec;
+        else
+                return now(CLOCK_MONOTONIC) + usec;
+}
+
+static int timeout_compare(const void *a, const void *b) {
+        const struct reply_callback *x = a, *y = b;
+
+        if (x->timeout_usec != 0 && y->timeout_usec == 0)
+                return -1;
+
+        if (x->timeout_usec == 0 && y->timeout_usec != 0)
+                return 1;
+
+        return CMP(x->timeout_usec, y->timeout_usec);
+}
+
+_public_ int sd_bus_call_async(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                sd_bus_message *_m,
+                sd_bus_message_handler_t callback,
+                void *userdata,
+                uint64_t usec) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        _cleanup_(sd_bus_slot_unrefp) sd_bus_slot *s = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL);
+        assert_return(!m->sealed || (!!callback == !(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)), -EINVAL);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* If no callback is specified and there's no interest in a slot, then there's no reason to ask for a reply */
+        if (!callback && !slot && !m->sealed)
+                m->header->flags |= BUS_MESSAGE_NO_REPLY_EXPECTED;
+
+        r = ordered_hashmap_ensure_allocated(&bus->reply_callbacks, &uint64_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = prioq_ensure_allocated(&bus->reply_callbacks_prioq, timeout_compare);
+        if (r < 0)
+                return r;
+
+        r = bus_seal_message(bus, m, usec);
+        if (r < 0)
+                return r;
+
+        r = bus_remarshal_message(bus, &m);
+        if (r < 0)
+                return r;
+
+        if (slot || callback) {
+                s = bus_slot_allocate(bus, !slot, BUS_REPLY_CALLBACK, sizeof(struct reply_callback), userdata);
+                if (!s)
+                        return -ENOMEM;
+
+                s->reply_callback.callback = callback;
+
+                s->reply_callback.cookie = BUS_MESSAGE_COOKIE(m);
+                r = ordered_hashmap_put(bus->reply_callbacks, &s->reply_callback.cookie, &s->reply_callback);
+                if (r < 0) {
+                        s->reply_callback.cookie = 0;
+                        return r;
+                }
+
+                s->reply_callback.timeout_usec = calc_elapse(bus, m->timeout);
+                if (s->reply_callback.timeout_usec != 0) {
+                        r = prioq_put(bus->reply_callbacks_prioq, &s->reply_callback, &s->reply_callback.prioq_idx);
+                        if (r < 0) {
+                                s->reply_callback.timeout_usec = 0;
+                                return r;
+                        }
+                }
+        }
+
+        r = sd_bus_send(bus, m, s ? &s->reply_callback.cookie : NULL);
+        if (r < 0)
+                return r;
+
+        if (slot)
+                *slot = s;
+        s = NULL;
+
+        return r;
+}
+
+int bus_ensure_running(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->state == BUS_RUNNING)
+                return 1;
+
+        for (;;) {
+                if (IN_SET(bus->state, BUS_UNSET, BUS_CLOSED, BUS_CLOSING))
+                        return -ENOTCONN;
+
+                r = sd_bus_process(bus, NULL);
+                if (r < 0)
+                        return r;
+                if (bus->state == BUS_RUNNING)
+                        return 1;
+                if (r > 0)
+                        continue;
+
+                r = sd_bus_wait(bus, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+}
+
+_public_ int sd_bus_call(
+                sd_bus *bus,
+                sd_bus_message *_m,
+                uint64_t usec,
+                sd_bus_error *error,
+                sd_bus_message **reply) {
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        usec_t timeout;
+        uint64_t cookie;
+        size_t i;
+        int r;
+
+        bus_assert_return(m, -EINVAL, error);
+        bus_assert_return(m->header->type == SD_BUS_MESSAGE_METHOD_CALL, -EINVAL, error);
+        bus_assert_return(!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED), -EINVAL, error);
+        bus_assert_return(!bus_error_is_dirty(error), -EINVAL, error);
+
+        if (bus)
+                assert_return(bus = bus_resolve(bus), -ENOPKG);
+        else
+                assert_return(bus = m->bus, -ENOTCONN);
+        bus_assert_return(!bus_pid_changed(bus), -ECHILD, error);
+
+        if (!BUS_IS_OPEN(bus->state)) {
+                r = -ENOTCONN;
+                goto fail;
+        }
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                goto fail;
+
+        i = bus->rqueue_size;
+
+        r = bus_seal_message(bus, m, usec);
+        if (r < 0)
+                goto fail;
+
+        r = bus_remarshal_message(bus, &m);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_send(bus, m, &cookie);
+        if (r < 0)
+                goto fail;
+
+        timeout = calc_elapse(bus, m->timeout);
+
+        for (;;) {
+                usec_t left;
+
+                while (i < bus->rqueue_size) {
+                        _cleanup_(sd_bus_message_unrefp) sd_bus_message *incoming = NULL;
+
+                        incoming = sd_bus_message_ref(bus->rqueue[i]);
+
+                        if (incoming->reply_cookie == cookie) {
+                                /* Found a match! */
+
+                                rqueue_drop_one(bus, i);
+                                log_debug_bus_message(incoming);
+
+                                if (incoming->header->type == SD_BUS_MESSAGE_METHOD_RETURN) {
+
+                                        if (incoming->n_fds <= 0 || bus->accept_fd) {
+                                                if (reply)
+                                                        *reply = TAKE_PTR(incoming);
+
+                                                return 1;
+                                        }
+
+                                        return sd_bus_error_setf(error, SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Reply message contained file descriptors which I couldn't accept. Sorry.");
+
+                                } else if (incoming->header->type == SD_BUS_MESSAGE_METHOD_ERROR)
+                                        return sd_bus_error_copy(error, &incoming->error);
+                                else {
+                                        r = -EIO;
+                                        goto fail;
+                                }
+
+                        } else if (BUS_MESSAGE_COOKIE(incoming) == cookie &&
+                                   bus->unique_name &&
+                                   incoming->sender &&
+                                   streq(bus->unique_name, incoming->sender)) {
+
+                                rqueue_drop_one(bus, i);
+
+                                /* Our own message? Somebody is trying to send its own client a message,
+                                 * let's not dead-lock, let's fail immediately. */
+
+                                r = -ELOOP;
+                                goto fail;
+                        }
+
+                        /* Try to read more, right-away */
+                        i++;
+                }
+
+                r = bus_read_message(bus);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                r = -ECONNRESET;
+                        }
+
+                        goto fail;
+                }
+                if (r > 0)
+                        continue;
+
+                if (timeout > 0) {
+                        usec_t n;
+
+                        n = now(CLOCK_MONOTONIC);
+                        if (n >= timeout) {
+                                r = -ETIMEDOUT;
+                                goto fail;
+                        }
+
+                        left = timeout - n;
+                } else
+                        left = (uint64_t) -1;
+
+                r = bus_poll(bus, true, left);
+                if (r < 0)
+                        goto fail;
+                if (r == 0) {
+                        r = -ETIMEDOUT;
+                        goto fail;
+                }
+
+                r = dispatch_wqueue(bus);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                r = -ECONNRESET;
+                        }
+
+                        goto fail;
+                }
+        }
+
+fail:
+        return sd_bus_error_set_errno(error, r);
+}
+
+_public_ int sd_bus_get_fd(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(bus->input_fd == bus->output_fd, -EPERM);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSED)
+                return -ENOTCONN;
+
+        if (bus->inotify_fd >= 0)
+                return bus->inotify_fd;
+
+        if (bus->input_fd >= 0)
+                return bus->input_fd;
+
+        return -ENOTCONN;
+}
+
+_public_ int sd_bus_get_events(sd_bus *bus) {
+        int flags = 0;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        switch (bus->state) {
+
+        case BUS_UNSET:
+        case BUS_CLOSED:
+                return -ENOTCONN;
+
+        case BUS_WATCH_BIND:
+                flags |= POLLIN;
+                break;
+
+        case BUS_OPENING:
+                flags |= POLLOUT;
+                break;
+
+        case BUS_AUTHENTICATING:
+                if (bus_socket_auth_needs_write(bus))
+                        flags |= POLLOUT;
+
+                flags |= POLLIN;
+                break;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                if (bus->rqueue_size <= 0)
+                        flags |= POLLIN;
+                if (bus->wqueue_size > 0)
+                        flags |= POLLOUT;
+                break;
+
+        case BUS_CLOSING:
+                break;
+
+        default:
+                assert_not_reached("Unknown state");
+        }
+
+        return flags;
+}
+
+_public_ int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
+        struct reply_callback *c;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(timeout_usec, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state) && bus->state != BUS_CLOSING)
+                return -ENOTCONN;
+
+        if (bus->track_queue) {
+                *timeout_usec = 0;
+                return 1;
+        }
+
+        switch (bus->state) {
+
+        case BUS_AUTHENTICATING:
+                *timeout_usec = bus->auth_timeout;
+                return 1;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                if (bus->rqueue_size > 0) {
+                        *timeout_usec = 0;
+                        return 1;
+                }
+
+                c = prioq_peek(bus->reply_callbacks_prioq);
+                if (!c) {
+                        *timeout_usec = (uint64_t) -1;
+                        return 0;
+                }
+
+                if (c->timeout_usec == 0) {
+                        *timeout_usec = (uint64_t) -1;
+                        return 0;
+                }
+
+                *timeout_usec = c->timeout_usec;
+                return 1;
+
+        case BUS_CLOSING:
+                *timeout_usec = 0;
+                return 1;
+
+        case BUS_WATCH_BIND:
+        case BUS_OPENING:
+                *timeout_usec = (uint64_t) -1;
+                return 0;
+
+        default:
+                assert_not_reached("Unknown or unexpected stat");
+        }
+}
+
+static int process_timeout(sd_bus *bus) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message* m = NULL;
+        struct reply_callback *c;
+        sd_bus_slot *slot;
+        bool is_hello;
+        usec_t n;
+        int r;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        c = prioq_peek(bus->reply_callbacks_prioq);
+        if (!c)
+                return 0;
+
+        n = now(CLOCK_MONOTONIC);
+        if (c->timeout_usec > n)
+                return 0;
+
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->cookie,
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Method call timed out"),
+                        &m);
+        if (r < 0)
+                return r;
+
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        assert_se(prioq_pop(bus->reply_callbacks_prioq) == c);
+        c->timeout_usec = 0;
+
+        ordered_hashmap_remove(bus->reply_callbacks, &c->cookie);
+        c->cookie = 0;
+
+        slot = container_of(c, sd_bus_slot, reply_callback);
+
+        bus->iteration_counter++;
+
+        is_hello = bus->state == BUS_HELLO && c->callback == hello_callback;
+
+        bus->current_message = m;
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+        bus->current_message = NULL;
+
+        if (slot->floating)
+                bus_slot_disconnect(slot, true);
+
+        sd_bus_slot_unref(slot);
+
+        /* When this is the hello message and it timed out, then make sure to propagate the error up, don't just log
+         * and ignore the callback handler's return value. */
+        if (is_hello)
+                return r;
+
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
+
+static int process_hello(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        if (bus->state != BUS_HELLO)
+                return 0;
+
+        /* Let's make sure the first message on the bus is the HELLO
+         * reply. But note that we don't actually parse the message
+         * here (we leave that to the usual handling), we just verify
+         * we don't let any earlier msg through. */
+
+        if (!IN_SET(m->header->type, SD_BUS_MESSAGE_METHOD_RETURN, SD_BUS_MESSAGE_METHOD_ERROR))
+                return -EIO;
+
+        if (m->reply_cookie != 1)
+                return -EIO;
+
+        return 0;
+}
+
+static int process_reply(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *synthetic_reply = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        struct reply_callback *c;
+        sd_bus_slot *slot;
+        bool is_hello;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (!IN_SET(m->header->type, SD_BUS_MESSAGE_METHOD_RETURN, SD_BUS_MESSAGE_METHOD_ERROR))
+                return 0;
+
+        if (m->destination && bus->unique_name && !streq_ptr(m->destination, bus->unique_name))
+                return 0;
+
+        c = ordered_hashmap_remove(bus->reply_callbacks, &m->reply_cookie);
+        if (!c)
+                return 0;
+
+        c->cookie = 0;
+
+        slot = container_of(c, sd_bus_slot, reply_callback);
+
+        if (m->n_fds > 0 && !bus->accept_fd) {
+
+                /* If the reply contained a file descriptor which we
+                 * didn't want we pass an error instead. */
+
+                r = bus_message_new_synthetic_error(
+                                bus,
+                                m->reply_cookie,
+                                &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Reply message contained file descriptor"),
+                                &synthetic_reply);
+                if (r < 0)
+                        return r;
+
+                /* Copy over original timestamp */
+                synthetic_reply->realtime = m->realtime;
+                synthetic_reply->monotonic = m->monotonic;
+                synthetic_reply->seqnum = m->seqnum;
+                synthetic_reply->read_counter = m->read_counter;
+
+                r = bus_seal_synthetic_message(bus, synthetic_reply);
+                if (r < 0)
+                        return r;
+
+                m = synthetic_reply;
+        } else {
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+        }
+
+        if (c->timeout_usec != 0) {
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout_usec = 0;
+        }
+
+        is_hello = bus->state == BUS_HELLO && c->callback == hello_callback;
+
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+
+        if (slot->floating)
+                bus_slot_disconnect(slot, true);
+
+        sd_bus_slot_unref(slot);
+
+        /* When this is the hello message and it failed, then make sure to propagate the error up, don't just log and
+         * ignore the callback handler's return value. */
+        if (is_hello)
+                return r;
+
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
+
+static int process_filter(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        struct filter_callback *l;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        do {
+                bus->filter_callbacks_modified = false;
+
+                LIST_FOREACH(callbacks, l, bus->filter_callbacks) {
+                        sd_bus_slot *slot;
+
+                        if (bus->filter_callbacks_modified)
+                                break;
+
+                        /* Don't run this more than once per iteration */
+                        if (l->last_iteration == bus->iteration_counter)
+                                continue;
+
+                        l->last_iteration = bus->iteration_counter;
+
+                        r = sd_bus_message_rewind(m, true);
+                        if (r < 0)
+                                return r;
+
+                        slot = container_of(l, sd_bus_slot, filter_callback);
+
+                        bus->current_slot = sd_bus_slot_ref(slot);
+                        bus->current_handler = l->callback;
+                        bus->current_userdata = slot->userdata;
+                        r = l->callback(m, slot->userdata, &error_buffer);
+                        bus->current_userdata = NULL;
+                        bus->current_handler = NULL;
+                        bus->current_slot = sd_bus_slot_unref(slot);
+
+                        r = bus_maybe_reply_error(m, r, &error_buffer);
+                        if (r != 0)
+                                return r;
+
+                }
+
+        } while (bus->filter_callbacks_modified);
+
+        return 0;
+}
+
+static int process_match(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        do {
+                bus->match_callbacks_modified = false;
+
+                r = bus_match_run(bus, &bus->match_callbacks, m);
+                if (r != 0)
+                        return r;
+
+        } while (bus->match_callbacks_modified);
+
+        return 0;
+}
+
+static int process_builtin(sd_bus *bus, sd_bus_message *m) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (bus->manual_peer_interface)
+                return 0;
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 0;
+
+        if (!streq_ptr(m->interface, "org.freedesktop.DBus.Peer"))
+                return 0;
+
+        if (m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
+                return 1;
+
+        if (streq_ptr(m->member, "Ping"))
+                r = sd_bus_message_new_method_return(m, &reply);
+        else if (streq_ptr(m->member, "GetMachineId")) {
+                sd_id128_t id;
+                char sid[SD_ID128_STRING_MAX];
+
+                r = sd_id128_get_machine(&id);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_new_method_return(m, &reply);
+                if (r < 0)
+                        return r;
+
+                r = sd_bus_message_append(reply, "s", sd_id128_to_string(id, sid));
+        } else {
+                r = sd_bus_message_new_method_errorf(
+                                m, &reply,
+                                SD_BUS_ERROR_UNKNOWN_METHOD,
+                                 "Unknown method '%s' on interface '%s'.", m->member, m->interface);
+        }
+        if (r < 0)
+                return r;
+
+        r = sd_bus_send(bus, reply, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int process_fd_check(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        /* If we got a message with a file descriptor which we didn't
+         * want to accept, then let's drop it. How can this even
+         * happen? For example, when the kernel queues a message into
+         * an activatable names's queue which allows fds, and then is
+         * delivered to us later even though we ourselves did not
+         * negotiate it. */
+
+        if (bus->is_monitor)
+                return 0;
+
+        if (m->n_fds <= 0)
+                return 0;
+
+        if (bus->accept_fd)
+                return 0;
+
+        if (m->header->type != SD_BUS_MESSAGE_METHOD_CALL)
+                return 1; /* just eat it up */
+
+        return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Message contains file descriptors, which I cannot accept. Sorry.");
+}
+
+static int process_message(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert(bus);
+        assert(m);
+
+        bus->current_message = m;
+        bus->iteration_counter++;
+
+        log_debug_bus_message(m);
+
+        r = process_hello(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_reply(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_fd_check(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_filter(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_match(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_builtin(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = bus_process_object(bus, m);
+
+finish:
+        bus->current_message = NULL;
+        return r;
+}
+
+static int dispatch_track(sd_bus *bus) {
+        assert(bus);
+
+        if (!bus->track_queue)
+                return 0;
+
+        bus_track_dispatch(bus->track_queue);
+        return 1;
+}
+
+static int process_running(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        int r;
+
+        assert(bus);
+        assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
+
+        r = process_timeout(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_wqueue(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_track(bus);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_rqueue(bus, &m);
+        if (r < 0)
+                return r;
+        if (!m)
+                goto null_message;
+
+        r = process_message(bus, m);
+        if (r != 0)
+                goto null_message;
+
+        if (ret) {
+                r = sd_bus_message_rewind(m, true);
+                if (r < 0)
+                        return r;
+
+                *ret = TAKE_PTR(m);
+                return 1;
+        }
+
+        if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) {
+
+                log_debug("Unprocessed message call sender=%s object=%s interface=%s member=%s",
+                          strna(sd_bus_message_get_sender(m)),
+                          strna(sd_bus_message_get_path(m)),
+                          strna(sd_bus_message_get_interface(m)),
+                          strna(sd_bus_message_get_member(m)));
+
+                r = sd_bus_reply_method_errorf(
+                                m,
+                                SD_BUS_ERROR_UNKNOWN_OBJECT,
+                                "Unknown object '%s'.", m->path);
+                if (r < 0)
+                        return r;
+        }
+
+        return 1;
+
+null_message:
+        if (r >= 0 && ret)
+                *ret = NULL;
+
+        return r;
+}
+
+static int bus_exit_now(sd_bus *bus) {
+        assert(bus);
+
+        /* Exit due to close, if this is requested. If this is bus object is attached to an event source, invokes
+         * sd_event_exit(), otherwise invokes libc exit(). */
+
+        if (bus->exited) /* did we already exit? */
+                return 0;
+        if (!bus->exit_triggered) /* was the exit condition triggered? */
+                return 0;
+        if (!bus->exit_on_disconnect) /* Shall we actually exit on disconnection? */
+                return 0;
+
+        bus->exited = true; /* never exit more than once */
+
+        log_debug("Bus connection disconnected, exiting.");
+
+        if (bus->event)
+                return sd_event_exit(bus->event, EXIT_FAILURE);
+        else
+                exit(EXIT_FAILURE);
+
+        assert_not_reached("exit() didn't exit?");
+}
+
+static int process_closing_reply_callback(sd_bus *bus, struct reply_callback *c) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        sd_bus_slot *slot;
+        int r;
+
+        assert(bus);
+        assert(c);
+
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->cookie,
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Connection terminated"),
+                        &m);
+        if (r < 0)
+                return r;
+
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        if (c->timeout_usec != 0) {
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout_usec = 0;
+        }
+
+        ordered_hashmap_remove(bus->reply_callbacks, &c->cookie);
+        c->cookie = 0;
+
+        slot = container_of(c, sd_bus_slot, reply_callback);
+
+        bus->iteration_counter++;
+
+        bus->current_message = m;
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+        bus->current_message = NULL;
+
+        if (slot->floating)
+                bus_slot_disconnect(slot, true);
+
+        sd_bus_slot_unref(slot);
+
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
+
+static int process_closing(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct reply_callback *c;
+        int r;
+
+        assert(bus);
+        assert(bus->state == BUS_CLOSING);
+
+        /* First, fail all outstanding method calls */
+        c = ordered_hashmap_first(bus->reply_callbacks);
+        if (c)
+                return process_closing_reply_callback(bus, c);
+
+        /* Then, fake-drop all remaining bus tracking references */
+        if (bus->tracks) {
+                bus_track_close(bus->tracks);
+                return 1;
+        }
+
+        /* Then, synthesize a Disconnected message */
+        r = sd_bus_message_new_signal(
+                        bus,
+                        &m,
+                        "/org/freedesktop/DBus/Local",
+                        "org.freedesktop.DBus.Local",
+                        "Disconnected");
+        if (r < 0)
+                return r;
+
+        bus_message_set_sender_local(bus, m);
+        m->read_counter = ++bus->read_counter;
+
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
+
+        sd_bus_close(bus);
+
+        bus->current_message = m;
+        bus->iteration_counter++;
+
+        r = process_filter(bus, m);
+        if (r != 0)
+                goto finish;
+
+        r = process_match(bus, m);
+        if (r != 0)
+                goto finish;
+
+        /* Nothing else to do, exit now, if the condition holds */
+        bus->exit_triggered = true;
+        (void) bus_exit_now(bus);
+
+        if (ret)
+                *ret = TAKE_PTR(m);
+
+        r = 1;
+
+finish:
+        bus->current_message = NULL;
+
+        return r;
+}
+
+static int bus_process_internal(sd_bus *bus, sd_bus_message **ret) {
+        int r;
+
+        /* Returns 0 when we didn't do anything. This should cause the
+         * caller to invoke sd_bus_wait() before returning the next
+         * time. Returns > 0 when we did something, which possibly
+         * means *ret is filled in with an unprocessed message. */
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        /* We don't allow recursively invoking sd_bus_process(). */
+        assert_return(!bus->current_message, -EBUSY);
+        assert(!bus->current_slot); /* This should be NULL whenever bus->current_message is */
+
+        BUS_DONT_DESTROY(bus);
+
+        switch (bus->state) {
+
+        case BUS_UNSET:
+                return -ENOTCONN;
+
+        case BUS_CLOSED:
+                return -ECONNRESET;
+
+        case BUS_WATCH_BIND:
+                r = bus_socket_process_watch_bind(bus);
+                break;
+
+        case BUS_OPENING:
+                r = bus_socket_process_opening(bus);
+                break;
+
+        case BUS_AUTHENTICATING:
+                r = bus_socket_process_authenticating(bus);
+                break;
+
+        case BUS_RUNNING:
+        case BUS_HELLO:
+                r = process_running(bus, ret);
+                if (r >= 0)
+                        return r;
+
+                /* This branch initializes *ret, hence we don't use the generic error checking below */
+                break;
+
+        case BUS_CLOSING:
+                return process_closing(bus, ret);
+
+        default:
+                assert_not_reached("Unknown state");
+        }
+
+        if (ERRNO_IS_DISCONNECT(r)) {
+                bus_enter_closing(bus);
+                r = 1;
+        } else if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = NULL;
+
+        return r;
+}
+
+_public_ int sd_bus_process(sd_bus *bus, sd_bus_message **ret) {
+        return bus_process_internal(bus, ret);
+}
+
+_public_ int sd_bus_process_priority(sd_bus *bus, int64_t priority, sd_bus_message **ret) {
+        return bus_process_internal(bus, ret);
+}
+
+static int bus_poll(sd_bus *bus, bool need_more, uint64_t timeout_usec) {
+        struct pollfd p[2] = {};
+        int r, n;
+        struct timespec ts;
+        usec_t m = USEC_INFINITY;
+
+        assert(bus);
+
+        if (bus->state == BUS_CLOSING)
+                return 1;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (bus->state == BUS_WATCH_BIND) {
+                assert(bus->inotify_fd >= 0);
+
+                p[0].events = POLLIN;
+                p[0].fd = bus->inotify_fd;
+                n = 1;
+        } else {
+                int e;
+
+                e = sd_bus_get_events(bus);
+                if (e < 0)
+                        return e;
+
+                if (need_more)
+                        /* The caller really needs some more data, he doesn't
+                         * care about what's already read, or any timeouts
+                         * except its own. */
+                        e |= POLLIN;
+                else {
+                        usec_t until;
+                        /* The caller wants to process if there's something to
+                         * process, but doesn't care otherwise */
+
+                        r = sd_bus_get_timeout(bus, &until);
+                        if (r < 0)
+                                return r;
+                        if (r > 0)
+                                m = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
+                }
+
+                p[0].fd = bus->input_fd;
+                if (bus->output_fd == bus->input_fd) {
+                        p[0].events = e;
+                        n = 1;
+                } else {
+                        p[0].events = e & POLLIN;
+                        p[1].fd = bus->output_fd;
+                        p[1].events = e & POLLOUT;
+                        n = 2;
+                }
+        }
+
+        if (timeout_usec != (uint64_t) -1 && (m == USEC_INFINITY || timeout_usec < m))
+                m = timeout_usec;
+
+        r = ppoll(p, n, m == USEC_INFINITY ? NULL : timespec_store(&ts, m), NULL);
+        if (r < 0)
+                return -errno;
+        if (r == 0)
+                return 0;
+
+        if (p[0].revents & POLLNVAL)
+                return -EBADF;
+        if (n >= 2 && (p[1].revents & POLLNVAL))
+                return -EBADF;
+
+        return 1;
+}
+
+_public_ int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec) {
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING)
+                return 0;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        if (bus->rqueue_size > 0)
+                return 0;
+
+        return bus_poll(bus, false, timeout_usec);
+}
+
+_public_ int sd_bus_flush(sd_bus *bus) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->state == BUS_CLOSING)
+                return 0;
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* We never were connected? Don't hang in inotify for good, as there's no timeout set for it */
+        if (bus->state == BUS_WATCH_BIND)
+                return -EUNATCH;
+
+        r = bus_ensure_running(bus);
+        if (r < 0)
+                return r;
+
+        if (bus->wqueue_size <= 0)
+                return 0;
+
+        for (;;) {
+                r = dispatch_wqueue(bus);
+                if (r < 0) {
+                        if (ERRNO_IS_DISCONNECT(r)) {
+                                bus_enter_closing(bus);
+                                return -ECONNRESET;
+                        }
+
+                        return r;
+                }
+
+                if (bus->wqueue_size <= 0)
+                        return 0;
+
+                r = bus_poll(bus, false, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+}
+
+_public_ int sd_bus_add_filter(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        sd_bus_slot *s;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(callback, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        s = bus_slot_allocate(bus, !slot, BUS_FILTER_CALLBACK, sizeof(struct filter_callback), userdata);
+        if (!s)
+                return -ENOMEM;
+
+        s->filter_callback.callback = callback;
+
+        bus->filter_callbacks_modified = true;
+        LIST_PREPEND(callbacks, bus->filter_callbacks, &s->filter_callback);
+
+        if (slot)
+                *slot = s;
+
+        return 0;
+}
+
+static int add_match_callback(
+                sd_bus_message *m,
+                void *userdata,
+                sd_bus_error *ret_error) {
+
+        sd_bus_slot *match_slot = userdata;
+        bool failed = false;
+        int r;
+
+        assert(m);
+        assert(match_slot);
+
+        sd_bus_slot_ref(match_slot);
+
+        if (sd_bus_message_is_method_error(m, NULL)) {
+                log_debug_errno(sd_bus_message_get_errno(m),
+                                "Unable to add match %s, failing connection: %s",
+                                match_slot->match_callback.match_string,
+                                sd_bus_message_get_error(m)->message);
+
+                failed = true;
+        } else
+                log_debug("Match %s successfully installed.", match_slot->match_callback.match_string);
+
+        if (match_slot->match_callback.install_callback) {
+                sd_bus *bus;
+
+                bus = sd_bus_message_get_bus(m);
+
+                /* This function has been called as slot handler, and we want to call another slot handler. Let's
+                 * update the slot callback metadata temporarily with our own data, and then revert back to the old
+                 * values. */
+
+                assert(bus->current_slot == match_slot->match_callback.install_slot);
+                assert(bus->current_handler == add_match_callback);
+                assert(bus->current_userdata == userdata);
+
+                bus->current_slot = match_slot;
+                bus->current_handler = match_slot->match_callback.install_callback;
+                bus->current_userdata = match_slot->userdata;
+
+                r = match_slot->match_callback.install_callback(m, match_slot->userdata, ret_error);
+
+                bus->current_slot = match_slot->match_callback.install_slot;
+                bus->current_handler = add_match_callback;
+                bus->current_userdata = userdata;
+        } else {
+                if (failed) /* Generic failure handling: destroy the connection */
+                        bus_enter_closing(sd_bus_message_get_bus(m));
+
+                r = 1;
+        }
+
+        /* We don't need the install method reply slot anymore, let's free it */
+        match_slot->match_callback.install_slot = sd_bus_slot_unref(match_slot->match_callback.install_slot);
+
+        if (failed && match_slot->floating)
+                bus_slot_disconnect(match_slot, true);
+
+        sd_bus_slot_unref(match_slot);
+
+        return r;
+}
+
+static int bus_add_match_full(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                bool asynchronous,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                sd_bus_message_handler_t install_callback,
+                void *userdata) {
+
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+        sd_bus_slot *s = NULL;
+        int r = 0;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(match, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        r = bus_match_parse(match, &components, &n_components);
+        if (r < 0)
+                goto finish;
+
+        s = bus_slot_allocate(bus, !slot, BUS_MATCH_CALLBACK, sizeof(struct match_callback), userdata);
+        if (!s) {
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        s->match_callback.callback = callback;
+        s->match_callback.install_callback = install_callback;
+
+        if (bus->bus_client) {
+                enum bus_match_scope scope;
+
+                scope = bus_match_get_scope(components, n_components);
+
+                /* Do not install server-side matches for matches against the local service, interface or bus path. */
+                if (scope != BUS_MATCH_LOCAL) {
+
+                        /* We store the original match string, so that we can use it to remove the match again. */
+
+                        s->match_callback.match_string = strdup(match);
+                        if (!s->match_callback.match_string) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        if (asynchronous) {
+                                r = bus_add_match_internal_async(bus,
+                                                                 &s->match_callback.install_slot,
+                                                                 s->match_callback.match_string,
+                                                                 add_match_callback,
+                                                                 s);
+
+                                if (r < 0)
+                                        return r;
+
+                                /* Make the slot of the match call floating now. We need the reference, but we don't
+                                 * want that this match pins the bus object, hence we first create it non-floating, but
+                                 * then make it floating. */
+                                r = sd_bus_slot_set_floating(s->match_callback.install_slot, true);
+                        } else
+                                r = bus_add_match_internal(bus, s->match_callback.match_string, &s->match_callback.after);
+                        if (r < 0)
+                                goto finish;
+
+                        s->match_added = true;
+                }
+        }
+
+        bus->match_callbacks_modified = true;
+        r = bus_match_add(&bus->match_callbacks, components, n_components, &s->match_callback);
+        if (r < 0)
+                goto finish;
+
+        if (slot)
+                *slot = s;
+        s = NULL;
+
+finish:
+        bus_match_parse_free(components, n_components);
+        sd_bus_slot_unref(s);
+
+        return r;
+}
+
+_public_ int sd_bus_add_match(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                void *userdata) {
+
+        return bus_add_match_full(bus, slot, false, match, callback, NULL, userdata);
+}
+
+_public_ int sd_bus_add_match_async(
+                sd_bus *bus,
+                sd_bus_slot **slot,
+                const char *match,
+                sd_bus_message_handler_t callback,
+                sd_bus_message_handler_t install_callback,
+                void *userdata) {
+
+        return bus_add_match_full(bus, slot, true, match, callback, install_callback, userdata);
+}
+
+bool bus_pid_changed(sd_bus *bus) {
+        assert(bus);
+
+        /* We don't support people creating a bus connection and
+         * keeping it around over a fork(). Let's complain. */
+
+        return bus->original_pid != getpid_cached();
+}
+
+static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_bus *bus = userdata;
+        int r;
+
+        assert(bus);
+
+        /* Note that this is called both on input_fd, output_fd as well as inotify_fd events */
+
+        r = sd_bus_process(bus, NULL);
+        if (r < 0) {
+                log_debug_errno(r, "Processing of bus failed, closing down: %m");
+                bus_enter_closing(bus);
+        }
+
+        return 1;
+}
+
+static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_bus *bus = userdata;
+        int r;
+
+        assert(bus);
+
+        r = sd_bus_process(bus, NULL);
+        if (r < 0) {
+                log_debug_errno(r, "Processing of bus failed, closing down: %m");
+                bus_enter_closing(bus);
+        }
+
+        return 1;
+}
+
+static int prepare_callback(sd_event_source *s, void *userdata) {
+        sd_bus *bus = userdata;
+        int r, e;
+        usec_t until;
+
+        assert(s);
+        assert(bus);
+
+        e = sd_bus_get_events(bus);
+        if (e < 0) {
+                r = e;
+                goto fail;
+        }
+
+        if (bus->output_fd != bus->input_fd) {
+
+                r = sd_event_source_set_io_events(bus->input_io_event_source, e & POLLIN);
+                if (r < 0)
+                        goto fail;
+
+                r = sd_event_source_set_io_events(bus->output_io_event_source, e & POLLOUT);
+        } else
+                r = sd_event_source_set_io_events(bus->input_io_event_source, e);
+        if (r < 0)
+                goto fail;
+
+        r = sd_bus_get_timeout(bus, &until);
+        if (r < 0)
+                goto fail;
+        if (r > 0) {
+                int j;
+
+                j = sd_event_source_set_time(bus->time_event_source, until);
+                if (j < 0) {
+                        r = j;
+                        goto fail;
+                }
+        }
+
+        r = sd_event_source_set_enabled(bus->time_event_source, r > 0);
+        if (r < 0)
+                goto fail;
+
+        return 1;
+
+fail:
+        log_debug_errno(r, "Preparing of bus events failed, closing down: %m");
+        bus_enter_closing(bus);
+
+        return 1;
+}
+
+static int quit_callback(sd_event_source *event, void *userdata) {
+        sd_bus *bus = userdata;
+
+        assert(event);
+
+        if (bus->close_on_exit) {
+                sd_bus_flush(bus);
+                sd_bus_close(bus);
+        }
+
+        return 1;
+}
+
+int bus_attach_io_events(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->input_fd < 0)
+                return 0;
+
+        if (!bus->event)
+                return 0;
+
+        if (!bus->input_io_event_source) {
+                r = sd_event_add_io(bus->event, &bus->input_io_event_source, bus->input_fd, 0, io_callback, bus);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_prepare(bus->input_io_event_source, prepare_callback);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_priority(bus->input_io_event_source, bus->event_priority);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_description(bus->input_io_event_source, "bus-input");
+        } else
+                r = sd_event_source_set_io_fd(bus->input_io_event_source, bus->input_fd);
+
+        if (r < 0)
+                return r;
+
+        if (bus->output_fd != bus->input_fd) {
+                assert(bus->output_fd >= 0);
+
+                if (!bus->output_io_event_source) {
+                        r = sd_event_add_io(bus->event, &bus->output_io_event_source, bus->output_fd, 0, io_callback, bus);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_event_source_set_priority(bus->output_io_event_source, bus->event_priority);
+                        if (r < 0)
+                                return r;
+
+                        r = sd_event_source_set_description(bus->input_io_event_source, "bus-output");
+                } else
+                        r = sd_event_source_set_io_fd(bus->output_io_event_source, bus->output_fd);
+
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static void bus_detach_io_events(sd_bus *bus) {
+        assert(bus);
+
+        if (bus->input_io_event_source) {
+                sd_event_source_set_enabled(bus->input_io_event_source, SD_EVENT_OFF);
+                bus->input_io_event_source = sd_event_source_unref(bus->input_io_event_source);
+        }
+
+        if (bus->output_io_event_source) {
+                sd_event_source_set_enabled(bus->output_io_event_source, SD_EVENT_OFF);
+                bus->output_io_event_source = sd_event_source_unref(bus->output_io_event_source);
+        }
+}
+
+int bus_attach_inotify_event(sd_bus *bus) {
+        int r;
+
+        assert(bus);
+
+        if (bus->inotify_fd < 0)
+                return 0;
+
+        if (!bus->event)
+                return 0;
+
+        if (!bus->inotify_event_source) {
+                r = sd_event_add_io(bus->event, &bus->inotify_event_source, bus->inotify_fd, EPOLLIN, io_callback, bus);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_priority(bus->inotify_event_source, bus->event_priority);
+                if (r < 0)
+                        return r;
+
+                r = sd_event_source_set_description(bus->inotify_event_source, "bus-inotify");
+        } else
+                r = sd_event_source_set_io_fd(bus->inotify_event_source, bus->inotify_fd);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static void bus_detach_inotify_event(sd_bus *bus) {
+        assert(bus);
+
+        if (bus->inotify_event_source) {
+                sd_event_source_set_enabled(bus->inotify_event_source, SD_EVENT_OFF);
+                bus->inotify_event_source = sd_event_source_unref(bus->inotify_event_source);
+        }
+}
+
+_public_ int sd_bus_attach_event(sd_bus *bus, sd_event *event, int priority) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus->event, -EBUSY);
+
+        assert(!bus->input_io_event_source);
+        assert(!bus->output_io_event_source);
+        assert(!bus->time_event_source);
+
+        if (event)
+                bus->event = sd_event_ref(event);
+        else  {
+                r = sd_event_default(&bus->event);
+                if (r < 0)
+                        return r;
+        }
+
+        bus->event_priority = priority;
+
+        r = sd_event_add_time(bus->event, &bus->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, bus);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(bus->time_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(bus->time_event_source, "bus-time");
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_exit(bus->event, &bus->quit_event_source, quit_callback, bus);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(bus->quit_event_source, "bus-exit");
+        if (r < 0)
+                goto fail;
+
+        r = bus_attach_io_events(bus);
+        if (r < 0)
+                goto fail;
+
+        r = bus_attach_inotify_event(bus);
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        sd_bus_detach_event(bus);
+        return r;
+}
+
+_public_ int sd_bus_detach_event(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        if (!bus->event)
+                return 0;
+
+        bus_detach_io_events(bus);
+        bus_detach_inotify_event(bus);
+
+        if (bus->time_event_source) {
+                sd_event_source_set_enabled(bus->time_event_source, SD_EVENT_OFF);
+                bus->time_event_source = sd_event_source_unref(bus->time_event_source);
+        }
+
+        if (bus->quit_event_source) {
+                sd_event_source_set_enabled(bus->quit_event_source, SD_EVENT_OFF);
+                bus->quit_event_source = sd_event_source_unref(bus->quit_event_source);
+        }
+
+        bus->event = sd_event_unref(bus->event);
+        return 1;
+}
+
+_public_ sd_event* sd_bus_get_event(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->event;
+}
+
+_public_ sd_bus_message* sd_bus_get_current_message(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_message;
+}
+
+_public_ sd_bus_slot* sd_bus_get_current_slot(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_slot;
+}
+
+_public_ sd_bus_message_handler_t sd_bus_get_current_handler(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_handler;
+}
+
+_public_ void* sd_bus_get_current_userdata(sd_bus *bus) {
+        assert_return(bus = bus_resolve(bus), NULL);
+
+        return bus->current_userdata;
+}
+
+static int bus_default(int (*bus_open)(sd_bus **), sd_bus **default_bus, sd_bus **ret) {
+        sd_bus *b = NULL;
+        int r;
+
+        assert(bus_open);
+        assert(default_bus);
+
+        if (!ret)
+                return !!*default_bus;
+
+        if (*default_bus) {
+                *ret = sd_bus_ref(*default_bus);
+                return 0;
+        }
+
+        r = bus_open(&b);
+        if (r < 0)
+                return r;
+
+        b->default_bus_ptr = default_bus;
+        b->tid = gettid();
+        *default_bus = b;
+
+        *ret = b;
+        return 1;
+}
+
+_public_ int sd_bus_default_system(sd_bus **ret) {
+        return bus_default(sd_bus_open_system, &default_system_bus, ret);
+}
+
+_public_ int sd_bus_default_user(sd_bus **ret) {
+        return bus_default(sd_bus_open_user, &default_user_bus, ret);
+}
+
+_public_ int sd_bus_default(sd_bus **ret) {
+        int (*bus_open)(sd_bus **) = NULL;
+        sd_bus **busp;
+
+        busp = bus_choose_default(&bus_open);
+        return bus_default(bus_open, busp, ret);
+}
+
+_public_ int sd_bus_get_tid(sd_bus *b, pid_t *tid) {
+        assert_return(b, -EINVAL);
+        assert_return(tid, -EINVAL);
+        assert_return(!bus_pid_changed(b), -ECHILD);
+
+        if (b->tid != 0) {
+                *tid = b->tid;
+                return 0;
+        }
+
+        if (b->event)
+                return sd_event_get_tid(b->event, tid);
+
+        return -ENXIO;
+}
+
+_public_ int sd_bus_path_encode(const char *prefix, const char *external_id, char **ret_path) {
+        _cleanup_free_ char *e = NULL;
+        char *ret;
+
+        assert_return(object_path_is_valid(prefix), -EINVAL);
+        assert_return(external_id, -EINVAL);
+        assert_return(ret_path, -EINVAL);
+
+        e = bus_label_escape(external_id);
+        if (!e)
+                return -ENOMEM;
+
+        ret = path_join(prefix, e);
+        if (!ret)
+                return -ENOMEM;
+
+        *ret_path = ret;
+        return 0;
+}
+
+_public_ int sd_bus_path_decode(const char *path, const char *prefix, char **external_id) {
+        const char *e;
+        char *ret;
+
+        assert_return(object_path_is_valid(path), -EINVAL);
+        assert_return(object_path_is_valid(prefix), -EINVAL);
+        assert_return(external_id, -EINVAL);
+
+        e = object_path_startswith(path, prefix);
+        if (!e) {
+                *external_id = NULL;
+                return 0;
+        }
+
+        ret = bus_label_unescape(e);
+        if (!ret)
+                return -ENOMEM;
+
+        *external_id = ret;
+        return 1;
+}
+
+_public_ int sd_bus_path_encode_many(char **out, const char *path_template, ...) {
+        _cleanup_strv_free_ char **labels = NULL;
+        char *path, *path_pos, **label_pos;
+        const char *sep, *template_pos;
+        size_t path_length;
+        va_list list;
+        int r;
+
+        assert_return(out, -EINVAL);
+        assert_return(path_template, -EINVAL);
+
+        path_length = strlen(path_template);
+
+        va_start(list, path_template);
+        for (sep = strchr(path_template, '%'); sep; sep = strchr(sep + 1, '%')) {
+                const char *arg;
+                char *label;
+
+                arg = va_arg(list, const char *);
+                if (!arg) {
+                        va_end(list);
+                        return -EINVAL;
+                }
+
+                label = bus_label_escape(arg);
+                if (!label) {
+                        va_end(list);
+                        return -ENOMEM;
+                }
+
+                r = strv_consume(&labels, label);
+                if (r < 0) {
+                        va_end(list);
+                        return r;
+                }
+
+                /* add label length, but account for the format character */
+                path_length += strlen(label) - 1;
+        }
+        va_end(list);
+
+        path = malloc(path_length + 1);
+        if (!path)
+                return -ENOMEM;
+
+        path_pos = path;
+        label_pos = labels;
+
+        for (template_pos = path_template; *template_pos; ) {
+                sep = strchrnul(template_pos, '%');
+                path_pos = mempcpy(path_pos, template_pos, sep - template_pos);
+                if (!*sep)
+                        break;
+
+                path_pos = stpcpy(path_pos, *label_pos++);
+                template_pos = sep + 1;
+        }
+
+        *path_pos = 0;
+        *out = path;
+        return 0;
+}
+
+_public_ int sd_bus_path_decode_many(const char *path, const char *path_template, ...) {
+        _cleanup_strv_free_ char **labels = NULL;
+        const char *template_pos, *path_pos;
+        char **label_pos;
+        va_list list;
+        int r;
+
+        /*
+         * This decodes an object-path based on a template argument. The
+         * template consists of a verbatim path, optionally including special
+         * directives:
+         *
+         *   - Each occurrence of '%' in the template matches an arbitrary
+         *     substring of a label in the given path. At most one such
+         *     directive is allowed per label. For each such directive, the
+         *     caller must provide an output parameter (char **) via va_arg. If
+         *     NULL is passed, the given label is verified, but not returned.
+         *     For each matched label, the *decoded* label is stored in the
+         *     passed output argument, and the caller is responsible to free
+         *     it. Note that the output arguments are only modified if the
+         *     actually path matched the template. Otherwise, they're left
+         *     untouched.
+         *
+         * This function returns <0 on error, 0 if the path does not match the
+         * template, 1 if it matched.
+         */
+
+        assert_return(path, -EINVAL);
+        assert_return(path_template, -EINVAL);
+
+        path_pos = path;
+
+        for (template_pos = path_template; *template_pos; ) {
+                const char *sep;
+                size_t length;
+                char *label;
+
+                /* verify everything until the next '%' matches verbatim */
+                sep = strchrnul(template_pos, '%');
+                length = sep - template_pos;
+                if (strncmp(path_pos, template_pos, length))
+                        return 0;
+
+                path_pos += length;
+                template_pos += length;
+
+                if (!*template_pos)
+                        break;
+
+                /* We found the next '%' character. Everything up until here
+                 * matched. We now skip ahead to the end of this label and make
+                 * sure it matches the tail of the label in the path. Then we
+                 * decode the string in-between and save it for later use. */
+
+                ++template_pos; /* skip over '%' */
+
+                sep = strchrnul(template_pos, '/');
+                length = sep - template_pos; /* length of suffix to match verbatim */
+
+                /* verify the suffixes match */
+                sep = strchrnul(path_pos, '/');
+                if (sep - path_pos < (ssize_t)length ||
+                    strncmp(sep - length, template_pos, length))
+                        return 0;
+
+                template_pos += length; /* skip over matched label */
+                length = sep - path_pos - length; /* length of sub-label to decode */
+
+                /* store unescaped label for later use */
+                label = bus_label_unescape_n(path_pos, length);
+                if (!label)
+                        return -ENOMEM;
+
+                r = strv_consume(&labels, label);
+                if (r < 0)
+                        return r;
+
+                path_pos = sep; /* skip decoded label and suffix */
+        }
+
+        /* end of template must match end of path */
+        if (*path_pos)
+                return 0;
+
+        /* copy the labels over to the caller */
+        va_start(list, path_template);
+        for (label_pos = labels; label_pos && *label_pos; ++label_pos) {
+                char **arg;
+
+                arg = va_arg(list, char **);
+                if (arg)
+                        *arg = *label_pos;
+                else
+                        free(*label_pos);
+        }
+        va_end(list);
+
+        labels = mfree(labels);
+        return 1;
+}
+
+_public_ int sd_bus_try_close(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return -EOPNOTSUPP;
+}
+
+_public_ int sd_bus_get_description(sd_bus *bus, const char **description) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(description, -EINVAL);
+        assert_return(bus->description, -ENXIO);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->description)
+                *description = bus->description;
+        else if (bus->is_system)
+                *description = "system";
+        else if (bus->is_user)
+                *description = "user";
+        else
+                *description = NULL;
+
+        return 0;
+}
+
+_public_ int sd_bus_get_scope(sd_bus *bus, const char **scope) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(scope, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->is_user) {
+                *scope = "user";
+                return 0;
+        }
+
+        if (bus->is_system) {
+                *scope = "system";
+                return 0;
+        }
+
+        return -ENODATA;
+}
+
+_public_ int sd_bus_get_address(sd_bus *bus, const char **address) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(address, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (bus->address) {
+                *address = bus->address;
+                return 0;
+        }
+
+        return -ENODATA;
+}
+
+_public_ int sd_bus_get_creds_mask(sd_bus *bus, uint64_t *mask) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(mask, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        *mask = bus->creds_mask;
+        return 0;
+}
+
+_public_ int sd_bus_is_bus_client(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->bus_client;
+}
+
+_public_ int sd_bus_is_server(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->is_server;
+}
+
+_public_ int sd_bus_is_anonymous(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->anonymous_auth;
+}
+
+_public_ int sd_bus_is_trusted(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->trusted;
+}
+
+_public_ int sd_bus_is_monitor(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        return bus->is_monitor;
+}
+
+static void flush_close(sd_bus *bus) {
+        if (!bus)
+                return;
+
+        /* Flushes and closes the specified bus. We take a ref before,
+         * to ensure the flushing does not cause the bus to be
+         * unreferenced. */
+
+        sd_bus_flush_close_unref(sd_bus_ref(bus));
+}
+
+_public_ void sd_bus_default_flush_close(void) {
+        flush_close(default_starter_bus);
+        flush_close(default_user_bus);
+        flush_close(default_system_bus);
+}
+
+_public_ int sd_bus_set_exit_on_disconnect(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        /* Turns on exit-on-disconnect, and triggers it immediately if the bus connection was already
+         * disconnected. Note that this is triggered exclusively on disconnections triggered by the server side, never
+         * from the client side. */
+        bus->exit_on_disconnect = b;
+
+        /* If the exit condition was triggered already, exit immediately. */
+        return bus_exit_now(bus);
+}
+
+_public_ int sd_bus_get_exit_on_disconnect(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        return bus->exit_on_disconnect;
+}
+
+_public_ int sd_bus_set_sender(sd_bus *bus, const char *sender) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus->bus_client, -EPERM);
+        assert_return(!sender || service_name_is_valid(sender), -EINVAL);
+
+        return free_and_strdup(&bus->patch_sender, sender);
+}
+
+_public_ int sd_bus_get_sender(sd_bus *bus, const char **ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(ret, -EINVAL);
+
+        if (!bus->patch_sender)
+                return -ENODATA;
+
+        *ret = bus->patch_sender;
+        return 0;
+}
+
+_public_ int sd_bus_get_n_queued_read(sd_bus *bus, uint64_t *ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(ret, -EINVAL);
+
+        *ret = bus->rqueue_size;
+        return 0;
+}
+
+_public_ int sd_bus_get_n_queued_write(sd_bus *bus, uint64_t *ret) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+        assert_return(ret, -EINVAL);
+
+        *ret = bus->wqueue_size;
+        return 0;
+}
+
+_public_ int sd_bus_set_method_call_timeout(sd_bus *bus, uint64_t usec) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        bus->method_call_timeout = usec;
+        return 0;
+}
+
+_public_ int sd_bus_get_method_call_timeout(sd_bus *bus, uint64_t *ret) {
+        const char *e;
+        usec_t usec;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(ret, -EINVAL);
+
+        if (bus->method_call_timeout != 0) {
+                *ret = bus->method_call_timeout;
+                return 0;
+        }
+
+        e = secure_getenv("SYSTEMD_BUS_TIMEOUT");
+        if (e && parse_sec(e, &usec) >= 0 && usec != 0) {
+                /* Save the parsed value to avoid multiple parsing. To change the timeout value,
+                 * use sd_bus_set_method_call_timeout() instead of setenv(). */
+                *ret = bus->method_call_timeout = usec;
+                return 0;
+        }
+
+        *ret = bus->method_call_timeout = BUS_DEFAULT_TIMEOUT;
+        return 0;
+}
+
+_public_ int sd_bus_set_close_on_exit(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        bus->close_on_exit = b;
+        return 0;
+}
+
+_public_ int sd_bus_get_close_on_exit(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+
+        return bus->close_on_exit;
+}
+
+_public_ int sd_bus_enqueue_for_read(sd_bus *bus, sd_bus_message *m) {
+        int r;
+
+        assert_return(bus, -EINVAL);
+        assert_return(bus = bus_resolve(bus), -ENOPKG);
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EINVAL);
+        assert_return(!bus_pid_changed(bus), -ECHILD);
+
+        if (!BUS_IS_OPEN(bus->state))
+                return -ENOTCONN;
+
+        /* Re-enqueue a message for reading. This is primarily useful for PolicyKit-style authentication,
+         * where we accept a message, then determine we need to interactively authenticate the user, and then
+         * we want to process the message again. */
+
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
+        bus->rqueue[bus->rqueue_size++] = bus_message_ref_queued(m, bus);
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-address.c b/src/libsystemd/sd-bus/test-bus-address.c
new file mode 100644
index 0000000..b92558f
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-address.c
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-bus.h"
+
+#include "bus-internal.h"
+#include "log.h"
+#include "string-util.h"
+#include "strv.h"
+#include "tests.h"
+
+static void test_one_address(sd_bus *b,
+                             const char *host,
+                             int result, const char *expected) {
+        int r;
+
+        r = bus_set_address_system_remote(b, host);
+        log_info("\"%s\" → %d, \"%s\"", host, r, strna(r >= 0 ? b->address : NULL));
+        if (result < 0 || expected) {
+                assert(r == result);
+                if (r >= 0)
+                        assert_se(streq(b->address, expected));
+        }
+}
+
+static void test_bus_set_address_system_remote(char **args) {
+        _cleanup_(sd_bus_unrefp) sd_bus *b = NULL;
+
+        assert_se(sd_bus_new(&b) >= 0);
+        if (!strv_isempty(args)) {
+                char **a;
+                STRV_FOREACH(a, args)
+                        test_one_address(b, *a, 0, NULL);
+                return;
+        };
+
+        test_one_address(b, "host",
+                         0, "unixexec:path=ssh,argv1=-xT,argv2=--,argv3=host,argv4=systemd-stdio-bridge");
+        test_one_address(b, "host:123",
+                         0, "unixexec:path=ssh,argv1=-xT,argv2=-p,argv3=123,argv4=--,argv5=host,argv6=systemd-stdio-bridge");
+        test_one_address(b, "host:123:123",
+                         -EINVAL, NULL);
+                test_one_address(b, "host:",
+                                 -EINVAL, NULL);
+        test_one_address(b, "user@host",
+                         0, "unixexec:path=ssh,argv1=-xT,argv2=--,argv3=user%40host,argv4=systemd-stdio-bridge");
+        test_one_address(b, "user@host@host",
+                         -EINVAL, NULL);
+        test_one_address(b, "[::1]",
+                         0, "unixexec:path=ssh,argv1=-xT,argv2=--,argv3=%3a%3a1,argv4=systemd-stdio-bridge");
+        test_one_address(b, "user@[::1]",
+                         0, "unixexec:path=ssh,argv1=-xT,argv2=--,argv3=user%40%3a%3a1,argv4=systemd-stdio-bridge");
+        test_one_address(b, "user@[::1]:99",
+                         0, "unixexec:path=ssh,argv1=-xT,argv2=-p,argv3=99,argv4=--,argv5=user%40%3a%3a1,argv6=systemd-stdio-bridge");
+        test_one_address(b, "user@[::1]:",
+                         -EINVAL, NULL);
+        test_one_address(b, "user@[::1:",
+                         -EINVAL, NULL);
+        test_one_address(b, "user@",
+                         -EINVAL, NULL);
+        test_one_address(b, "user@@",
+                         -EINVAL, NULL);
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_INFO);
+
+        test_bus_set_address_system_remote(argv + 1);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-benchmark.c b/src/libsystemd/sd-bus/test-bus-benchmark.c
new file mode 100644
index 0000000..8c67117
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-benchmark.c
@@ -0,0 +1,324 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-internal.h"
+#include "bus-kernel.h"
+#include "bus-util.h"
+#include "def.h"
+#include "fd-util.h"
+#include "missing_resource.h"
+#include "time-util.h"
+#include "util.h"
+
+#define MAX_SIZE (2*1024*1024)
+
+static usec_t arg_loop_usec = 100 * USEC_PER_MSEC;
+
+typedef enum Type {
+        TYPE_LEGACY,
+        TYPE_DIRECT,
+} Type;
+
+static void server(sd_bus *b, size_t *result) {
+        int r;
+
+        for (;;) {
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+
+                r = sd_bus_process(b, &m);
+                assert_se(r >= 0);
+
+                if (r == 0)
+                        assert_se(sd_bus_wait(b, USEC_INFINITY) >= 0);
+                if (!m)
+                        continue;
+
+                if (sd_bus_message_is_method_call(m, "benchmark.server", "Ping"))
+                        assert_se(sd_bus_reply_method_return(m, NULL) >= 0);
+                else if (sd_bus_message_is_method_call(m, "benchmark.server", "Work")) {
+                        const void *p;
+                        size_t sz;
+
+                        /* Make sure the mmap is mapped */
+                        assert_se(sd_bus_message_read_array(m, 'y', &p, &sz) > 0);
+
+                        r = sd_bus_reply_method_return(m, NULL);
+                        assert_se(r >= 0);
+                } else if (sd_bus_message_is_method_call(m, "benchmark.server", "Exit")) {
+                        uint64_t res;
+                        assert_se(sd_bus_message_read(m, "t", &res) > 0);
+
+                        *result = res;
+                        return;
+
+                } else if (!sd_bus_message_is_signal(m, NULL, NULL))
+                        assert_not_reached("Unknown method");
+        }
+}
+
+static void transaction(sd_bus *b, size_t sz, const char *server_name) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
+        uint8_t *p;
+
+        assert_se(sd_bus_message_new_method_call(b, &m, server_name, "/", "benchmark.server", "Work") >= 0);
+        assert_se(sd_bus_message_append_array_space(m, 'y', sz, (void**) &p) >= 0);
+
+        memset(p, 0x80, sz);
+
+        assert_se(sd_bus_call(b, m, 0, NULL, &reply) >= 0);
+}
+
+static void client_bisect(const char *address, const char *server_name) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *x = NULL;
+        size_t lsize, rsize, csize;
+        sd_bus *b;
+        int r;
+
+        r = sd_bus_new(&b);
+        assert_se(r >= 0);
+
+        r = sd_bus_set_address(b, address);
+        assert_se(r >= 0);
+
+        r = sd_bus_start(b);
+        assert_se(r >= 0);
+
+        r = sd_bus_call_method(b, server_name, "/", "benchmark.server", "Ping", NULL, NULL, NULL);
+        assert_se(r >= 0);
+
+        lsize = 1;
+        rsize = MAX_SIZE;
+
+        printf("SIZE\tCOPY\tMEMFD\n");
+
+        for (;;) {
+                usec_t t;
+                unsigned n_copying, n_memfd;
+
+                csize = (lsize + rsize) / 2;
+
+                if (csize <= lsize)
+                        break;
+
+                if (csize <= 0)
+                        break;
+
+                printf("%zu\t", csize);
+
+                b->use_memfd = 0;
+
+                t = now(CLOCK_MONOTONIC);
+                for (n_copying = 0;; n_copying++) {
+                        transaction(b, csize, server_name);
+                        if (now(CLOCK_MONOTONIC) >= t + arg_loop_usec)
+                                break;
+                }
+                printf("%u\t", (unsigned) ((n_copying * USEC_PER_SEC) / arg_loop_usec));
+
+                b->use_memfd = -1;
+
+                t = now(CLOCK_MONOTONIC);
+                for (n_memfd = 0;; n_memfd++) {
+                        transaction(b, csize, server_name);
+                        if (now(CLOCK_MONOTONIC) >= t + arg_loop_usec)
+                                break;
+                }
+                printf("%u\n", (unsigned) ((n_memfd * USEC_PER_SEC) / arg_loop_usec));
+
+                if (n_copying == n_memfd)
+                        break;
+
+                if (n_copying > n_memfd)
+                        lsize = csize;
+                else
+                        rsize = csize;
+        }
+
+        b->use_memfd = 1;
+        assert_se(sd_bus_message_new_method_call(b, &x, server_name, "/", "benchmark.server", "Exit") >= 0);
+        assert_se(sd_bus_message_append(x, "t", csize) >= 0);
+        assert_se(sd_bus_send(b, x, NULL) >= 0);
+
+        sd_bus_unref(b);
+}
+
+static void client_chart(Type type, const char *address, const char *server_name, int fd) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *x = NULL;
+        size_t csize;
+        sd_bus *b;
+        int r;
+
+        r = sd_bus_new(&b);
+        assert_se(r >= 0);
+
+        if (type == TYPE_DIRECT) {
+                r = sd_bus_set_fd(b, fd, fd);
+                assert_se(r >= 0);
+        } else {
+                r = sd_bus_set_address(b, address);
+                assert_se(r >= 0);
+
+                r = sd_bus_set_bus_client(b, true);
+                assert_se(r >= 0);
+        }
+
+        r = sd_bus_start(b);
+        assert_se(r >= 0);
+
+        r = sd_bus_call_method(b, server_name, "/", "benchmark.server", "Ping", NULL, NULL, NULL);
+        assert_se(r >= 0);
+
+        switch (type) {
+        case TYPE_LEGACY:
+                printf("SIZE\tLEGACY\n");
+                break;
+        case TYPE_DIRECT:
+                printf("SIZE\tDIRECT\n");
+                break;
+        }
+
+        for (csize = 1; csize <= MAX_SIZE; csize *= 2) {
+                usec_t t;
+                unsigned n_memfd;
+
+                printf("%zu\t", csize);
+
+                t = now(CLOCK_MONOTONIC);
+                for (n_memfd = 0;; n_memfd++) {
+                        transaction(b, csize, server_name);
+                        if (now(CLOCK_MONOTONIC) >= t + arg_loop_usec)
+                                break;
+                }
+
+                printf("%u\n", (unsigned) ((n_memfd * USEC_PER_SEC) / arg_loop_usec));
+        }
+
+        b->use_memfd = 1;
+        assert_se(sd_bus_message_new_method_call(b, &x, server_name, "/", "benchmark.server", "Exit") >= 0);
+        assert_se(sd_bus_message_append(x, "t", csize) >= 0);
+        assert_se(sd_bus_send(b, x, NULL) >= 0);
+
+        sd_bus_unref(b);
+}
+
+int main(int argc, char *argv[]) {
+        enum {
+                MODE_BISECT,
+                MODE_CHART,
+        } mode = MODE_BISECT;
+        Type type = TYPE_LEGACY;
+        int i, pair[2] = { -1, -1 };
+        _cleanup_free_ char *address = NULL, *server_name = NULL;
+        _cleanup_close_ int bus_ref = -1;
+        const char *unique;
+        cpu_set_t cpuset;
+        size_t result;
+        sd_bus *b;
+        pid_t pid;
+        int r;
+
+        for (i = 1; i < argc; i++) {
+                if (streq(argv[i], "chart")) {
+                        mode = MODE_CHART;
+                        continue;
+                } else if (streq(argv[i], "legacy")) {
+                        type = TYPE_LEGACY;
+                        continue;
+                } else if (streq(argv[i], "direct")) {
+                        type = TYPE_DIRECT;
+                        continue;
+                }
+
+                assert_se(parse_sec(argv[i], &arg_loop_usec) >= 0);
+        }
+
+        assert_se(arg_loop_usec > 0);
+
+        if (type == TYPE_LEGACY) {
+                const char *e;
+
+                e = secure_getenv("DBUS_SESSION_BUS_ADDRESS");
+                assert_se(e);
+
+                address = strdup(e);
+                assert_se(address);
+        }
+
+        r = sd_bus_new(&b);
+        assert_se(r >= 0);
+
+        if (type == TYPE_DIRECT) {
+                assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, pair) >= 0);
+
+                r = sd_bus_set_fd(b, pair[0], pair[0]);
+                assert_se(r >= 0);
+
+                r = sd_bus_set_server(b, true, SD_ID128_NULL);
+                assert_se(r >= 0);
+        } else {
+                r = sd_bus_set_address(b, address);
+                assert_se(r >= 0);
+
+                r = sd_bus_set_bus_client(b, true);
+                assert_se(r >= 0);
+        }
+
+        r = sd_bus_start(b);
+        assert_se(r >= 0);
+
+        if (type != TYPE_DIRECT) {
+                r = sd_bus_get_unique_name(b, &unique);
+                assert_se(r >= 0);
+
+                server_name = strdup(unique);
+                assert_se(server_name);
+        }
+
+        sync();
+        setpriority(PRIO_PROCESS, 0, -19);
+
+        pid = fork();
+        assert_se(pid >= 0);
+
+        if (pid == 0) {
+                CPU_ZERO(&cpuset);
+                CPU_SET(0, &cpuset);
+                pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);
+
+                safe_close(bus_ref);
+                sd_bus_unref(b);
+
+                switch (mode) {
+                case MODE_BISECT:
+                        client_bisect(address, server_name);
+                        break;
+
+                case MODE_CHART:
+                        client_chart(type, address, server_name, pair[1]);
+                        break;
+                }
+
+                _exit(EXIT_SUCCESS);
+        }
+
+        CPU_ZERO(&cpuset);
+        CPU_SET(1, &cpuset);
+        pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);
+
+        server(b, &result);
+
+        if (mode == MODE_BISECT)
+                printf("Copying/memfd are equally fast at %zu bytes\n", result);
+
+        assert_se(waitpid(pid, NULL, 0) == pid);
+
+        safe_close(pair[1]);
+        sd_bus_unref(b);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-chat.c b/src/libsystemd/sd-bus/test-bus-chat.c
new file mode 100644
index 0000000..c3c31c6
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-chat.c
@@ -0,0 +1,547 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-error.h"
+#include "bus-internal.h"
+#include "bus-match.h"
+#include "bus-util.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "log.h"
+#include "macro.h"
+#include "tests.h"
+#include "util.h"
+
+static int match_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        log_info("Match triggered! interface=%s member=%s", strna(sd_bus_message_get_interface(m)), strna(sd_bus_message_get_member(m)));
+        return 0;
+}
+
+static int object_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        int r;
+
+        if (sd_bus_message_is_method_error(m, NULL))
+                return 0;
+
+        if (sd_bus_message_is_method_call(m, "org.object.test", "Foobar")) {
+                log_info("Invoked Foobar() on %s", sd_bus_message_get_path(m));
+
+                r = sd_bus_reply_method_return(m, NULL);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to send reply: %m");
+
+                return 1;
+        }
+
+        return 0;
+}
+
+static int server_init(sd_bus **_bus) {
+        sd_bus *bus = NULL;
+        sd_id128_t id;
+        int r;
+        const char *unique, *desc;
+
+        assert_se(_bus);
+
+        r = sd_bus_open_user_with_description(&bus, "my bus!");
+        if (r < 0) {
+                log_error_errno(r, "Failed to connect to user bus: %m");
+                goto fail;
+        }
+
+        r = sd_bus_get_bus_id(bus, &id);
+        if (r < 0) {
+                log_error_errno(r, "Failed to get server ID: %m");
+                goto fail;
+        }
+
+        r = sd_bus_get_unique_name(bus, &unique);
+        if (r < 0) {
+                log_error_errno(r, "Failed to get unique name: %m");
+                goto fail;
+        }
+
+        assert_se(sd_bus_get_description(bus, &desc) >= 0);
+        assert_se(streq(desc, "my bus!"));
+
+        log_info("Peer ID is " SD_ID128_FORMAT_STR ".", SD_ID128_FORMAT_VAL(id));
+        log_info("Unique ID: %s", unique);
+        log_info("Can send file handles: %i", sd_bus_can_send(bus, 'h'));
+
+        r = sd_bus_request_name(bus, "org.freedesktop.systemd.test", 0);
+        if (r < 0) {
+                log_error_errno(r, "Failed to acquire name: %m");
+                goto fail;
+        }
+
+        r = sd_bus_add_fallback(bus, NULL, "/foo/bar", object_callback, NULL);
+        if (r < 0) {
+                log_error_errno(r, "Failed to add object: %m");
+                goto fail;
+        }
+
+        r = sd_bus_match_signal(bus, NULL, NULL, NULL, "foo.bar", "Notify", match_callback, NULL);
+        if (r < 0) {
+                log_error_errno(r, "Failed to request match: %m");
+                goto fail;
+        }
+
+        r = sd_bus_add_match(bus, NULL, "type='signal',interface='org.freedesktop.DBus',member='NameOwnerChanged'", match_callback, NULL);
+        if (r < 0) {
+                log_error_errno(r, "Failed to add match: %m");
+                goto fail;
+        }
+
+        bus_match_dump(&bus->match_callbacks, 0);
+
+        *_bus = bus;
+        return 0;
+
+fail:
+        sd_bus_unref(bus);
+        return r;
+}
+
+static int server(sd_bus *bus) {
+        int r;
+        bool client1_gone = false, client2_gone = false;
+
+        while (!client1_gone || !client2_gone) {
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+                pid_t pid = 0;
+                const char *label = NULL;
+
+                r = sd_bus_process(bus, &m);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to process requests: %m");
+                        goto fail;
+                }
+
+                if (r == 0) {
+                        r = sd_bus_wait(bus, (uint64_t) -1);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to wait: %m");
+                                goto fail;
+                        }
+
+                        continue;
+                }
+
+                if (!m)
+                        continue;
+
+                sd_bus_creds_get_pid(sd_bus_message_get_creds(m), &pid);
+                sd_bus_creds_get_selinux_context(sd_bus_message_get_creds(m), &label);
+                log_info("Got message! member=%s pid="PID_FMT" label=%s",
+                         strna(sd_bus_message_get_member(m)),
+                         pid,
+                         strna(label));
+                /* sd_bus_message_dump(m); */
+                /* sd_bus_message_rewind(m, true); */
+
+                if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "LowerCase")) {
+                        const char *hello;
+                        _cleanup_free_ char *lowercase = NULL;
+
+                        r = sd_bus_message_read(m, "s", &hello);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to get parameter: %m");
+                                goto fail;
+                        }
+
+                        lowercase = strdup(hello);
+                        if (!lowercase) {
+                                r = log_oom();
+                                goto fail;
+                        }
+
+                        ascii_strlower(lowercase);
+
+                        r = sd_bus_reply_method_return(m, "s", lowercase);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+                } else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "ExitClient1")) {
+
+                        r = sd_bus_reply_method_return(m, NULL);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+
+                        client1_gone = true;
+                } else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "ExitClient2")) {
+
+                        r = sd_bus_reply_method_return(m, NULL);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+
+                        client2_gone = true;
+                } else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "Slow")) {
+
+                        sleep(1);
+
+                        r = sd_bus_reply_method_return(m, NULL);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+
+                } else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "FileDescriptor")) {
+                        int fd;
+                        static const char x = 'X';
+
+                        r = sd_bus_message_read(m, "h", &fd);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to get parameter: %m");
+                                goto fail;
+                        }
+
+                        log_info("Received fd=%d", fd);
+
+                        if (write(fd, &x, 1) < 0) {
+                                log_error_errno(errno, "Failed to write to fd: %m");
+                                safe_close(fd);
+                                goto fail;
+                        }
+
+                        r = sd_bus_reply_method_return(m, NULL);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+
+                } else if (sd_bus_message_is_method_call(m, NULL, NULL)) {
+
+                        r = sd_bus_reply_method_error(
+                                        m,
+                                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_UNKNOWN_METHOD, "Unknown method."));
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+                }
+        }
+
+        r = 0;
+
+fail:
+        if (bus) {
+                sd_bus_flush(bus);
+                sd_bus_unref(bus);
+        }
+
+        return r;
+}
+
+static void* client1(void *p) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        const char *hello;
+        int r;
+        _cleanup_close_pair_ int pp[2] = { -1, -1 };
+        char x;
+
+        r = sd_bus_open_user(&bus);
+        if (r < 0) {
+                log_error_errno(r, "Failed to connect to user bus: %m");
+                goto finish;
+        }
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.systemd.test",
+                        "LowerCase",
+                        &error,
+                        &reply,
+                        "s",
+                        "HELLO");
+        if (r < 0) {
+                log_error_errno(r, "Failed to issue method call: %m");
+                goto finish;
+        }
+
+        r = sd_bus_message_read(reply, "s", &hello);
+        if (r < 0) {
+                log_error_errno(r, "Failed to get string: %m");
+                goto finish;
+        }
+
+        assert_se(streq(hello, "hello"));
+
+        if (pipe2(pp, O_CLOEXEC|O_NONBLOCK) < 0) {
+                r = log_error_errno(errno, "Failed to allocate pipe: %m");
+                goto finish;
+        }
+
+        log_info("Sending fd=%d", pp[1]);
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.systemd.test",
+                        "FileDescriptor",
+                        &error,
+                        NULL,
+                        "h",
+                        pp[1]);
+        if (r < 0) {
+                log_error_errno(r, "Failed to issue method call: %m");
+                goto finish;
+        }
+
+        errno = 0;
+        if (read(pp[0], &x, 1) <= 0) {
+                log_error("Failed to read from pipe: %s", errno != 0 ? strerror_safe(errno) : "early read");
+                goto finish;
+        }
+
+        r = 0;
+
+finish:
+        if (bus) {
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *q = NULL;
+
+                r = sd_bus_message_new_method_call(
+                                bus,
+                                &q,
+                                "org.freedesktop.systemd.test",
+                                "/",
+                                "org.freedesktop.systemd.test",
+                                "ExitClient1");
+                if (r < 0)
+                        log_error_errno(r, "Failed to allocate method call: %m");
+                else
+                        sd_bus_send(bus, q, NULL);
+
+        }
+
+        return INT_TO_PTR(r);
+}
+
+static int quit_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        bool *x = userdata;
+
+        log_error_errno(sd_bus_message_get_errno(m), "Quit callback: %m");
+
+        *x = 1;
+        return 1;
+}
+
+static void* client2(void *p) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        bool quit = false;
+        const char *mid;
+        int r;
+
+        r = sd_bus_open_user(&bus);
+        if (r < 0) {
+                log_error_errno(r, "Failed to connect to user bus: %m");
+                goto finish;
+        }
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.systemd.test",
+                        "/foo/bar/waldo/piep",
+                        "org.object.test",
+                        "Foobar");
+        if (r < 0) {
+                log_error_errno(r, "Failed to allocate method call: %m");
+                goto finish;
+        }
+
+        r = sd_bus_send(bus, m, NULL);
+        if (r < 0) {
+                log_error("Failed to issue method call: %s", bus_error_message(&error, r));
+                goto finish;
+        }
+
+        m = sd_bus_message_unref(m);
+
+        r = sd_bus_message_new_signal(
+                        bus,
+                        &m,
+                        "/foobar",
+                        "foo.bar",
+                        "Notify");
+        if (r < 0) {
+                log_error_errno(r, "Failed to allocate signal: %m");
+                goto finish;
+        }
+
+        r = sd_bus_send(bus, m, NULL);
+        if (r < 0) {
+                log_error("Failed to issue signal: %s", bus_error_message(&error, r));
+                goto finish;
+        }
+
+        m = sd_bus_message_unref(m);
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.DBus.Peer",
+                        "GetMachineId");
+        if (r < 0) {
+                log_error_errno(r, "Failed to allocate method call: %m");
+                goto finish;
+        }
+
+        r = sd_bus_call(bus, m, 0, &error, &reply);
+        if (r < 0) {
+                log_error("Failed to issue method call: %s", bus_error_message(&error, r));
+                goto finish;
+        }
+
+        r = sd_bus_message_read(reply, "s", &mid);
+        if (r < 0) {
+                log_error_errno(r, "Failed to parse machine ID: %m");
+                goto finish;
+        }
+
+        log_info("Machine ID is %s.", mid);
+
+        m = sd_bus_message_unref(m);
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.systemd.test",
+                        "Slow");
+        if (r < 0) {
+                log_error_errno(r, "Failed to allocate method call: %m");
+                goto finish;
+        }
+
+        reply = sd_bus_message_unref(reply);
+
+        r = sd_bus_call(bus, m, 200 * USEC_PER_MSEC, &error, &reply);
+        if (r < 0)
+                log_info("Failed to issue method call: %s", bus_error_message(&error, r));
+        else
+                log_info("Slow call succeed.");
+
+        m = sd_bus_message_unref(m);
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.systemd.test",
+                        "Slow");
+        if (r < 0) {
+                log_error_errno(r, "Failed to allocate method call: %m");
+                goto finish;
+        }
+
+        r = sd_bus_call_async(bus, NULL, m, quit_callback, &quit, 200 * USEC_PER_MSEC);
+        if (r < 0) {
+                log_info("Failed to issue method call: %s", bus_error_message(&error, r));
+                goto finish;
+        }
+
+        while (!quit) {
+                r = sd_bus_process(bus, NULL);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to process requests: %m");
+                        goto finish;
+                }
+                if (r == 0) {
+                        r = sd_bus_wait(bus, (uint64_t) -1);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to wait: %m");
+                                goto finish;
+                        }
+                }
+        }
+
+        r = 0;
+
+finish:
+        if (bus) {
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *q = NULL;
+
+                r = sd_bus_message_new_method_call(
+                                bus,
+                                &q,
+                                "org.freedesktop.systemd.test",
+                                "/",
+                                "org.freedesktop.systemd.test",
+                                "ExitClient2");
+                if (r < 0) {
+                        log_error_errno(r, "Failed to allocate method call: %m");
+                        goto finish;
+                }
+
+                (void) sd_bus_send(bus, q, NULL);
+        }
+
+        return INT_TO_PTR(r);
+}
+
+int main(int argc, char *argv[]) {
+        pthread_t c1, c2;
+        sd_bus *bus;
+        void *p;
+        int q, r;
+
+        test_setup_logging(LOG_INFO);
+
+        r = server_init(&bus);
+        if (r < 0)
+                return log_tests_skipped("Failed to connect to bus");
+
+        log_info("Initialized...");
+
+        r = pthread_create(&c1, NULL, client1, bus);
+        if (r != 0)
+                return EXIT_FAILURE;
+
+        r = pthread_create(&c2, NULL, client2, bus);
+        if (r != 0)
+                return EXIT_FAILURE;
+
+        r = server(bus);
+
+        q = pthread_join(c1, &p);
+        if (q != 0)
+                return EXIT_FAILURE;
+        if (PTR_TO_INT(p) < 0)
+                return EXIT_FAILURE;
+
+        q = pthread_join(c2, &p);
+        if (q != 0)
+                return EXIT_FAILURE;
+        if (PTR_TO_INT(p) < 0)
+                return EXIT_FAILURE;
+
+        if (r < 0)
+                return EXIT_FAILURE;
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-cleanup.c b/src/libsystemd/sd-bus/test-bus-cleanup.c
new file mode 100644
index 0000000..ece0a12
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-cleanup.c
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdio.h>
+
+#include "sd-bus.h"
+
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "tests.h"
+
+static bool use_system_bus = false;
+
+static void test_bus_new(void) {
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
+
+        assert_se(sd_bus_new(&bus) == 0);
+        assert_se(bus->n_ref == 1);
+}
+
+static int test_bus_open(void) {
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        int r;
+
+        r = sd_bus_open_user(&bus);
+        if (IN_SET(r, -ECONNREFUSED, -ENOENT, -ENOMEDIUM)) {
+                r = sd_bus_open_system(&bus);
+                if (IN_SET(r, -ECONNREFUSED, -ENOENT))
+                        return r;
+                use_system_bus = true;
+        }
+
+        assert_se(r >= 0);
+        assert_se(bus->n_ref >= 1); /* we send a hello message when opening, so the count is above 1 */
+
+        return 0;
+}
+
+static void test_bus_new_method_call(void) {
+        sd_bus *bus = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+
+        assert_se(use_system_bus ? sd_bus_open_system(&bus) >= 0 : sd_bus_open_user(&bus) >= 0);
+
+        assert_se(sd_bus_message_new_method_call(bus, &m, "a.service.name", "/an/object/path", "an.interface.name", "AMethodName") >= 0);
+
+        assert_se(m->n_ref == 1); /* We hold the only reference to the message */
+        assert_se(bus->n_ref >= 2);
+        sd_bus_flush_close_unref(bus);
+        assert_se(m->n_ref == 1);
+}
+
+static void test_bus_new_signal(void) {
+        sd_bus *bus = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+
+        assert_se(use_system_bus ? sd_bus_open_system(&bus) >= 0 : sd_bus_open_user(&bus) >= 0);
+
+        assert_se(sd_bus_message_new_signal(bus, &m, "/an/object/path", "an.interface.name", "Name") >= 0);
+
+        assert_se(m->n_ref == 1); /* We hold the only reference to the message */
+        assert_se(bus->n_ref >= 2);
+        sd_bus_flush_close_unref(bus);
+        assert_se(m->n_ref == 1);
+}
+
+int main(int argc, char **argv) {
+        test_setup_logging(LOG_INFO);
+
+        test_bus_new();
+
+        if (test_bus_open() < 0)
+                return log_tests_skipped("Failed to connect to bus");
+
+        test_bus_new_method_call();
+        test_bus_new_signal();
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-creds.c b/src/libsystemd/sd-bus/test-bus-creds.c
new file mode 100644
index 0000000..6551e69
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-creds.c
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-bus.h"
+
+#include "bus-dump.h"
+#include "bus-util.h"
+#include "cgroup-util.h"
+#include "tests.h"
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
+        int r;
+
+        test_setup_logging(LOG_DEBUG);
+
+        if (cg_unified() == -ENOMEDIUM)
+                return log_tests_skipped("/sys/fs/cgroup/ not available");
+
+        r = sd_bus_creds_new_from_pid(&creds, 0, _SD_BUS_CREDS_ALL);
+        log_full_errno(r < 0 ? LOG_ERR : LOG_DEBUG, r, "sd_bus_creds_new_from_pid: %m");
+        assert_se(r >= 0);
+
+        bus_creds_dump(creds, NULL, true);
+
+        creds = sd_bus_creds_unref(creds);
+
+        r = sd_bus_creds_new_from_pid(&creds, 1, _SD_BUS_CREDS_ALL);
+        if (r != -EACCES) {
+                assert_se(r >= 0);
+                putchar('\n');
+                bus_creds_dump(creds, NULL, true);
+        }
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-error.c b/src/libsystemd/sd-bus/test-bus-error.c
new file mode 100644
index 0000000..2e3803c
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-error.c
@@ -0,0 +1,299 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-bus.h"
+
+#include "bus-common-errors.h"
+#include "bus-error.h"
+#include "bus-util.h"
+#include "errno-list.h"
+#include "errno-util.h"
+
+static void test_error(void) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL, second = SD_BUS_ERROR_NULL;
+        const sd_bus_error const_error = SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_FILE_EXISTS, "const error");
+        const sd_bus_error temporarily_const_error = {
+                .name = SD_BUS_ERROR_ACCESS_DENIED,
+                .message = "oh! no",
+                ._need_free = -1
+        };
+
+        assert_se(!sd_bus_error_is_set(&error));
+        assert_se(sd_bus_error_set(&error, SD_BUS_ERROR_NOT_SUPPORTED, "xxx") == -EOPNOTSUPP);
+        assert_se(streq(error.name, SD_BUS_ERROR_NOT_SUPPORTED));
+        assert_se(streq(error.message, "xxx"));
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_NOT_SUPPORTED));
+        assert_se(sd_bus_error_has_names_sentinel(&error, SD_BUS_ERROR_NOT_SUPPORTED, NULL));
+        assert_se(sd_bus_error_has_names(&error, SD_BUS_ERROR_NOT_SUPPORTED));
+        assert_se(sd_bus_error_has_names(&error, SD_BUS_ERROR_NOT_SUPPORTED, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_has_names(&error, SD_BUS_ERROR_FILE_NOT_FOUND, SD_BUS_ERROR_NOT_SUPPORTED, NULL));
+        assert_se(!sd_bus_error_has_names(&error, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_get_errno(&error) == EOPNOTSUPP);
+        assert_se(sd_bus_error_is_set(&error));
+        sd_bus_error_free(&error);
+
+        /* Check with no error */
+        assert_se(!sd_bus_error_is_set(&error));
+        assert_se(sd_bus_error_setf(&error, NULL, "yyy %i", -1) == 0);
+        assert_se(error.name == NULL);
+        assert_se(error.message == NULL);
+        assert_se(!sd_bus_error_has_name(&error, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(!sd_bus_error_has_names(&error, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_get_errno(&error) == 0);
+        assert_se(!sd_bus_error_is_set(&error));
+
+        assert_se(sd_bus_error_setf(&error, SD_BUS_ERROR_FILE_NOT_FOUND, "yyy %i", -1) == -ENOENT);
+        assert_se(streq(error.name, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(streq(error.message, "yyy -1"));
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_has_names(&error, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_get_errno(&error) == ENOENT);
+        assert_se(sd_bus_error_is_set(&error));
+
+        assert_se(!sd_bus_error_is_set(&second));
+        assert_se(second._need_free == 0);
+        assert_se(error._need_free > 0);
+        assert_se(sd_bus_error_copy(&second, &error) == -ENOENT);
+        assert_se(second._need_free > 0);
+        assert_se(streq(error.name, second.name));
+        assert_se(streq(error.message, second.message));
+        assert_se(sd_bus_error_get_errno(&second) == ENOENT);
+        assert_se(sd_bus_error_has_name(&second, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_has_names(&second, SD_BUS_ERROR_FILE_NOT_FOUND));
+        assert_se(sd_bus_error_is_set(&second));
+
+        sd_bus_error_free(&error);
+        sd_bus_error_free(&second);
+
+        assert_se(!sd_bus_error_is_set(&second));
+        assert_se(const_error._need_free == 0);
+        assert_se(sd_bus_error_copy(&second, &const_error) == -EEXIST);
+        assert_se(second._need_free == 0);
+        assert_se(streq(const_error.name, second.name));
+        assert_se(streq(const_error.message, second.message));
+        assert_se(sd_bus_error_get_errno(&second) == EEXIST);
+        assert_se(sd_bus_error_has_name(&second, SD_BUS_ERROR_FILE_EXISTS));
+        assert_se(sd_bus_error_is_set(&second));
+        sd_bus_error_free(&second);
+
+        assert_se(!sd_bus_error_is_set(&second));
+        assert_se(temporarily_const_error._need_free < 0);
+        assert_se(sd_bus_error_copy(&second, &temporarily_const_error) == -EACCES);
+        assert_se(second._need_free > 0);
+        assert_se(streq(temporarily_const_error.name, second.name));
+        assert_se(streq(temporarily_const_error.message, second.message));
+        assert_se(sd_bus_error_get_errno(&second) == EACCES);
+        assert_se(sd_bus_error_has_name(&second, SD_BUS_ERROR_ACCESS_DENIED));
+        assert_se(sd_bus_error_is_set(&second));
+
+        assert_se(!sd_bus_error_is_set(&error));
+        assert_se(sd_bus_error_set_const(&error, "System.Error.EUCLEAN", "Hallo") == -EUCLEAN);
+        assert_se(streq(error.name, "System.Error.EUCLEAN"));
+        assert_se(streq(error.message, "Hallo"));
+        assert_se(sd_bus_error_has_name(&error, "System.Error.EUCLEAN"));
+        assert_se(sd_bus_error_get_errno(&error) == EUCLEAN);
+        assert_se(sd_bus_error_is_set(&error));
+        sd_bus_error_free(&error);
+
+        assert_se(!sd_bus_error_is_set(&error));
+        assert_se(sd_bus_error_set_errno(&error, EBUSY) == -EBUSY);
+        assert_se(streq(error.name, "System.Error.EBUSY"));
+        assert_se(streq(error.message, strerror_safe(EBUSY)));
+        assert_se(sd_bus_error_has_name(&error, "System.Error.EBUSY"));
+        assert_se(sd_bus_error_get_errno(&error) == EBUSY);
+        assert_se(sd_bus_error_is_set(&error));
+        sd_bus_error_free(&error);
+
+        assert_se(!sd_bus_error_is_set(&error));
+        assert_se(sd_bus_error_set_errnof(&error, EIO, "Waldi %c", 'X') == -EIO);
+        assert_se(streq(error.name, SD_BUS_ERROR_IO_ERROR));
+        assert_se(streq(error.message, "Waldi X"));
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_IO_ERROR));
+        assert_se(sd_bus_error_get_errno(&error) == EIO);
+        assert_se(sd_bus_error_is_set(&error));
+        sd_bus_error_free(&error);
+
+        /* Check with no error */
+        assert_se(!sd_bus_error_is_set(&error));
+        assert_se(sd_bus_error_set_errnof(&error, 0, "Waldi %c", 'X') == 0);
+        assert_se(error.name == NULL);
+        assert_se(error.message == NULL);
+        assert_se(!sd_bus_error_has_name(&error, SD_BUS_ERROR_IO_ERROR));
+        assert_se(sd_bus_error_get_errno(&error) == 0);
+        assert_se(!sd_bus_error_is_set(&error));
+}
+
+extern const sd_bus_error_map __start_SYSTEMD_BUS_ERROR_MAP[];
+extern const sd_bus_error_map __stop_SYSTEMD_BUS_ERROR_MAP[];
+
+static void dump_mapping_table(void) {
+        const sd_bus_error_map *m;
+
+        printf("----- errno mappings ------\n");
+        m = ALIGN_TO_PTR(__start_SYSTEMD_BUS_ERROR_MAP, sizeof(void*));
+        while (m < __stop_SYSTEMD_BUS_ERROR_MAP) {
+
+                if (m->code == BUS_ERROR_MAP_END_MARKER) {
+                        m = ALIGN_TO_PTR(m + 1, sizeof(void*));
+                        continue;
+                }
+
+                printf("%s -> %i/%s\n", strna(m->name), m->code, strna(errno_to_name(m->code)));
+                m++;
+        }
+        printf("---------------------------\n");
+}
+
+static void test_errno_mapping_standard(void) {
+        assert_se(sd_bus_error_set(NULL, "System.Error.EUCLEAN", NULL) == -EUCLEAN);
+        assert_se(sd_bus_error_set(NULL, "System.Error.EBUSY", NULL) == -EBUSY);
+        assert_se(sd_bus_error_set(NULL, "System.Error.EINVAL", NULL) == -EINVAL);
+        assert_se(sd_bus_error_set(NULL, "System.Error.WHATSIT", NULL) == -EIO);
+}
+
+BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map test_errors[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error", 5),
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-2", 52),
+        SD_BUS_ERROR_MAP_END
+};
+
+BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map test_errors2[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-3", 33),
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-4", 44),
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-33", 333),
+        SD_BUS_ERROR_MAP_END
+};
+
+static const sd_bus_error_map test_errors3[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-88", 888),
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-99", 999),
+        SD_BUS_ERROR_MAP_END
+};
+
+static const sd_bus_error_map test_errors4[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-77", 777),
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-78", 778),
+        SD_BUS_ERROR_MAP_END
+};
+
+static const sd_bus_error_map test_errors_bad1[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-1", 0),
+        SD_BUS_ERROR_MAP_END
+};
+
+static const sd_bus_error_map test_errors_bad2[] = {
+        SD_BUS_ERROR_MAP("org.freedesktop.custom-dbus-error-1", -1),
+        SD_BUS_ERROR_MAP_END
+};
+
+static void test_errno_mapping_custom(void) {
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error", NULL) == -5);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-2", NULL) == -52);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-x", NULL) == -EIO);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-33", NULL) == -333);
+
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-88", NULL) == -EIO);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-99", NULL) == -EIO);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-77", NULL) == -EIO);
+
+        assert_se(sd_bus_error_add_map(test_errors3) > 0);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-88", NULL) == -888);
+        assert_se(sd_bus_error_add_map(test_errors4) > 0);
+        assert_se(sd_bus_error_add_map(test_errors4) == 0);
+        assert_se(sd_bus_error_add_map(test_errors3) == 0);
+
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-99", NULL) == -999);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-77", NULL) == -777);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-78", NULL) == -778);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-2", NULL) == -52);
+        assert_se(sd_bus_error_set(NULL, "org.freedesktop.custom-dbus-error-y", NULL) == -EIO);
+
+        assert_se(sd_bus_error_set(NULL, BUS_ERROR_NO_SUCH_UNIT, NULL) == -ENOENT);
+
+        assert_se(sd_bus_error_add_map(test_errors_bad1) == -EINVAL);
+        assert_se(sd_bus_error_add_map(test_errors_bad2) == -EINVAL);
+}
+
+static void test_sd_bus_error_set_errnof(void) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_free_ char *str = NULL;
+
+        assert_se(sd_bus_error_set_errnof(NULL, 0, NULL) == 0);
+        assert_se(sd_bus_error_set_errnof(NULL, ENOANO, NULL) == -ENOANO);
+
+        assert_se(sd_bus_error_set_errnof(&error, 0, NULL) == 0);
+        assert_se(!bus_error_is_dirty(&error));
+
+        assert_se(sd_bus_error_set_errnof(&error, EACCES, NULL) == -EACCES);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_ACCESS_DENIED));
+        errno = EACCES;
+        assert_se(asprintf(&str, "%m") >= 0);
+        assert_se(streq(error.message, str));
+        assert_se(error._need_free == 0);
+
+        str = mfree(str);
+        sd_bus_error_free(&error);
+
+        assert_se(sd_bus_error_set_errnof(&error, ENOANO, NULL) == -ENOANO);
+        assert_se(sd_bus_error_has_name(&error, "System.Error.ENOANO"));
+        errno = ENOANO;
+        assert_se(asprintf(&str, "%m") >= 0);
+        assert_se(streq(error.message, str));
+        assert_se(error._need_free == 1);
+
+        str = mfree(str);
+        sd_bus_error_free(&error);
+
+        assert_se(sd_bus_error_set_errnof(&error, 100000, NULL) == -100000);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_FAILED));
+        errno = 100000;
+        assert_se(asprintf(&str, "%m") >= 0);
+        assert_se(streq(error.message, str));
+        assert_se(error._need_free == 1);
+
+        str = mfree(str);
+        sd_bus_error_free(&error);
+
+        assert_se(sd_bus_error_set_errnof(NULL, 0, "hoge %s: %m", "foo") == 0);
+        assert_se(sd_bus_error_set_errnof(NULL, ENOANO, "hoge %s: %m", "foo") == -ENOANO);
+
+        assert_se(sd_bus_error_set_errnof(&error, 0, "hoge %s: %m", "foo") == 0);
+        assert_se(!bus_error_is_dirty(&error));
+
+        assert_se(sd_bus_error_set_errnof(&error, EACCES, "hoge %s: %m", "foo") == -EACCES);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_ACCESS_DENIED));
+        errno = EACCES;
+        assert_se(asprintf(&str, "hoge %s: %m", "foo") >= 0);
+        assert_se(streq(error.message, str));
+        assert_se(error._need_free == 1);
+
+        str = mfree(str);
+        sd_bus_error_free(&error);
+
+        assert_se(sd_bus_error_set_errnof(&error, ENOANO, "hoge %s: %m", "foo") == -ENOANO);
+        assert_se(sd_bus_error_has_name(&error, "System.Error.ENOANO"));
+        errno = ENOANO;
+        assert_se(asprintf(&str, "hoge %s: %m", "foo") >= 0);
+        assert_se(streq(error.message, str));
+        assert_se(error._need_free == 1);
+
+        str = mfree(str);
+        sd_bus_error_free(&error);
+
+        assert_se(sd_bus_error_set_errnof(&error, 100000, "hoge %s: %m", "foo") == -100000);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_FAILED));
+        errno = 100000;
+        assert_se(asprintf(&str, "hoge %s: %m", "foo") >= 0);
+        assert_se(streq(error.message, str));
+        assert_se(error._need_free == 1);
+}
+
+int main(int argc, char *argv[]) {
+        dump_mapping_table();
+
+        test_error();
+        test_errno_mapping_standard();
+        test_errno_mapping_custom();
+        test_sd_bus_error_set_errnof();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-gvariant.c b/src/libsystemd/sd-bus/test-bus-gvariant.c
new file mode 100644
index 0000000..b0033f1
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-gvariant.c
@@ -0,0 +1,221 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#if HAVE_GLIB
+#include <glib.h>
+#endif
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-dump.h"
+#include "bus-gvariant.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "macro.h"
+#include "tests.h"
+#include "util.h"
+
+static void test_bus_gvariant_is_fixed_size(void) {
+        log_info("/* %s */", __func__);
+
+        assert_se(bus_gvariant_is_fixed_size("") > 0);
+        assert_se(bus_gvariant_is_fixed_size("()") == -EINVAL);
+        assert_se(bus_gvariant_is_fixed_size("y") > 0);
+        assert_se(bus_gvariant_is_fixed_size("u") > 0);
+        assert_se(bus_gvariant_is_fixed_size("b") > 0);
+        assert_se(bus_gvariant_is_fixed_size("n") > 0);
+        assert_se(bus_gvariant_is_fixed_size("q") > 0);
+        assert_se(bus_gvariant_is_fixed_size("i") > 0);
+        assert_se(bus_gvariant_is_fixed_size("t") > 0);
+        assert_se(bus_gvariant_is_fixed_size("d") > 0);
+        assert_se(bus_gvariant_is_fixed_size("s") == 0);
+        assert_se(bus_gvariant_is_fixed_size("o") == 0);
+        assert_se(bus_gvariant_is_fixed_size("g") == 0);
+        assert_se(bus_gvariant_is_fixed_size("h") > 0);
+        assert_se(bus_gvariant_is_fixed_size("ay") == 0);
+        assert_se(bus_gvariant_is_fixed_size("v") == 0);
+        assert_se(bus_gvariant_is_fixed_size("(u)") > 0);
+        assert_se(bus_gvariant_is_fixed_size("(uuuuy)") > 0);
+        assert_se(bus_gvariant_is_fixed_size("(uusuuy)") == 0);
+        assert_se(bus_gvariant_is_fixed_size("a{ss}") == 0);
+        assert_se(bus_gvariant_is_fixed_size("((u)yyy(b(iiii)))") > 0);
+        assert_se(bus_gvariant_is_fixed_size("((u)yyy(b(iiivi)))") == 0);
+}
+
+static void test_bus_gvariant_get_size(void) {
+        log_info("/* %s */", __func__);
+
+        assert_se(bus_gvariant_get_size("") == 0);
+        assert_se(bus_gvariant_get_size("()") == -EINVAL);
+        assert_se(bus_gvariant_get_size("y") == 1);
+        assert_se(bus_gvariant_get_size("u") == 4);
+        assert_se(bus_gvariant_get_size("b") == 1);
+        assert_se(bus_gvariant_get_size("n") == 2);
+        assert_se(bus_gvariant_get_size("q") == 2);
+        assert_se(bus_gvariant_get_size("i") == 4);
+        assert_se(bus_gvariant_get_size("t") == 8);
+        assert_se(bus_gvariant_get_size("d") == 8);
+        assert_se(bus_gvariant_get_size("s") < 0);
+        assert_se(bus_gvariant_get_size("o") < 0);
+        assert_se(bus_gvariant_get_size("g") < 0);
+        assert_se(bus_gvariant_get_size("h") == 4);
+        assert_se(bus_gvariant_get_size("ay") < 0);
+        assert_se(bus_gvariant_get_size("v") < 0);
+        assert_se(bus_gvariant_get_size("(u)") == 4);
+        assert_se(bus_gvariant_get_size("(uuuuy)") == 20);
+        assert_se(bus_gvariant_get_size("(uusuuy)") < 0);
+        assert_se(bus_gvariant_get_size("a{ss}") < 0);
+        assert_se(bus_gvariant_get_size("((u)yyy(b(iiii)))") == 28);
+        assert_se(bus_gvariant_get_size("((u)yyy(b(iiivi)))") < 0);
+        assert_se(bus_gvariant_get_size("((b)(t))") == 16);
+        assert_se(bus_gvariant_get_size("((b)(b)(t))") == 16);
+        assert_se(bus_gvariant_get_size("(bt)") == 16);
+        assert_se(bus_gvariant_get_size("((t)(b))") == 16);
+        assert_se(bus_gvariant_get_size("(tb)") == 16);
+        assert_se(bus_gvariant_get_size("((b)(b))") == 2);
+        assert_se(bus_gvariant_get_size("((t)(t))") == 16);
+}
+
+static void test_bus_gvariant_get_alignment(void) {
+        log_info("/* %s */", __func__);
+
+        assert_se(bus_gvariant_get_alignment("") == 1);
+        assert_se(bus_gvariant_get_alignment("()") == -EINVAL);
+        assert_se(bus_gvariant_get_alignment("y") == 1);
+        assert_se(bus_gvariant_get_alignment("b") == 1);
+        assert_se(bus_gvariant_get_alignment("u") == 4);
+        assert_se(bus_gvariant_get_alignment("s") == 1);
+        assert_se(bus_gvariant_get_alignment("o") == 1);
+        assert_se(bus_gvariant_get_alignment("g") == 1);
+        assert_se(bus_gvariant_get_alignment("v") == 8);
+        assert_se(bus_gvariant_get_alignment("h") == 4);
+        assert_se(bus_gvariant_get_alignment("i") == 4);
+        assert_se(bus_gvariant_get_alignment("t") == 8);
+        assert_se(bus_gvariant_get_alignment("x") == 8);
+        assert_se(bus_gvariant_get_alignment("q") == 2);
+        assert_se(bus_gvariant_get_alignment("n") == 2);
+        assert_se(bus_gvariant_get_alignment("d") == 8);
+        assert_se(bus_gvariant_get_alignment("ay") == 1);
+        assert_se(bus_gvariant_get_alignment("as") == 1);
+        assert_se(bus_gvariant_get_alignment("au") == 4);
+        assert_se(bus_gvariant_get_alignment("an") == 2);
+        assert_se(bus_gvariant_get_alignment("ans") == 2);
+        assert_se(bus_gvariant_get_alignment("ant") == 8);
+        assert_se(bus_gvariant_get_alignment("(ss)") == 1);
+        assert_se(bus_gvariant_get_alignment("(ssu)") == 4);
+        assert_se(bus_gvariant_get_alignment("a(ssu)") == 4);
+        assert_se(bus_gvariant_get_alignment("(u)") == 4);
+        assert_se(bus_gvariant_get_alignment("(uuuuy)") == 4);
+        assert_se(bus_gvariant_get_alignment("(uusuuy)") == 4);
+        assert_se(bus_gvariant_get_alignment("a{ss}") == 1);
+        assert_se(bus_gvariant_get_alignment("((u)yyy(b(iiii)))") == 4);
+        assert_se(bus_gvariant_get_alignment("((u)yyy(b(iiivi)))") == 8);
+        assert_se(bus_gvariant_get_alignment("((b)(t))") == 8);
+        assert_se(bus_gvariant_get_alignment("((b)(b)(t))") == 8);
+        assert_se(bus_gvariant_get_alignment("(bt)") == 8);
+        assert_se(bus_gvariant_get_alignment("((t)(b))") == 8);
+        assert_se(bus_gvariant_get_alignment("(tb)") == 8);
+        assert_se(bus_gvariant_get_alignment("((b)(b))") == 1);
+        assert_se(bus_gvariant_get_alignment("((t)(t))") == 8);
+}
+
+static int test_marshal(void) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *n = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        _cleanup_free_ void *blob = NULL;
+        size_t sz;
+        int r;
+
+        r = sd_bus_open_user(&bus);
+        if (r < 0)
+                r = sd_bus_open_system(&bus);
+        if (r < 0)
+                return log_tests_skipped_errno(r, "Failed to connect to bus");
+
+        bus->message_version = 2; /* dirty hack to enable gvariant */
+
+        r = sd_bus_message_new_method_call(bus, &m, "a.service.name",
+                                           "/an/object/path/which/is/really/really/long/so/that/we/hit/the/eight/bit/boundary/by/quite/some/margin/to/test/this/stuff/that/it/really/works",
+                                           "an.interface.name", "AMethodName");
+        assert_se(r >= 0);
+
+        assert_cc(sizeof(struct bus_header) == 16);
+
+        assert_se(sd_bus_message_append(m,
+                                        "a(usv)", 3,
+                                        4711, "first-string-parameter", "(st)", "X", (uint64_t) 1111,
+                                        4712, "second-string-parameter", "(a(si))", 2, "Y", 5, "Z", 6,
+                                        4713, "third-string-parameter", "(uu)", 1, 2) >= 0);
+
+        assert_se(sd_bus_message_seal(m, 4711, 0) >= 0);
+
+#if HAVE_GLIB
+        {
+                GVariant *v;
+                char *t;
+
+#if !defined(GLIB_VERSION_2_36)
+                g_type_init();
+#endif
+
+                v = g_variant_new_from_data(G_VARIANT_TYPE("(yyyyuta{tv})"), m->header, sizeof(struct bus_header) + m->fields_size, false, NULL, NULL);
+                assert_se(g_variant_is_normal_form(v));
+                t = g_variant_print(v, TRUE);
+                printf("%s\n", t);
+                g_free(t);
+                g_variant_unref(v);
+
+                v = g_variant_new_from_data(G_VARIANT_TYPE("(a(usv))"), m->body.data, m->user_body_size, false, NULL, NULL);
+                assert_se(g_variant_is_normal_form(v));
+                t = g_variant_print(v, TRUE);
+                printf("%s\n", t);
+                g_free(t);
+                g_variant_unref(v);
+        }
+#endif
+
+        assert_se(sd_bus_message_dump(m, NULL, SD_BUS_MESSAGE_DUMP_WITH_HEADER) >= 0);
+
+        assert_se(bus_message_get_blob(m, &blob, &sz) >= 0);
+
+#if HAVE_GLIB
+        {
+                GVariant *v;
+                char *t;
+
+                v = g_variant_new_from_data(G_VARIANT_TYPE("(yyyyuta{tv}v)"), blob, sz, false, NULL, NULL);
+                assert_se(g_variant_is_normal_form(v));
+                t = g_variant_print(v, TRUE);
+                printf("%s\n", t);
+                g_free(t);
+                g_variant_unref(v);
+        }
+#endif
+
+        assert_se(bus_message_from_malloc(bus, blob, sz, NULL, 0, NULL, &n) >= 0);
+        blob = NULL;
+
+        assert_se(sd_bus_message_dump(n, NULL, SD_BUS_MESSAGE_DUMP_WITH_HEADER) >= 0);
+
+        m = sd_bus_message_unref(m);
+
+        assert_se(sd_bus_message_new_method_call(bus, &m, "a.x", "/a/x", "a.x", "Ax") >= 0);
+
+        assert_se(sd_bus_message_append(m, "as", 0) >= 0);
+
+        assert_se(sd_bus_message_seal(m, 4712, 0) >= 0);
+        assert_se(sd_bus_message_dump(m, NULL, SD_BUS_MESSAGE_DUMP_WITH_HEADER) >= 0);
+
+        return EXIT_SUCCESS;
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_DEBUG);
+
+        test_bus_gvariant_is_fixed_size();
+        test_bus_gvariant_get_size();
+        test_bus_gvariant_get_alignment();
+
+        return test_marshal();
+}
diff --git a/src/libsystemd/sd-bus/test-bus-introspect.c b/src/libsystemd/sd-bus/test-bus-introspect.c
new file mode 100644
index 0000000..fb247c4
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-introspect.c
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-introspect.h"
+#include "log.h"
+#include "tests.h"
+
+#include "test-vtable-data.h"
+
+static void test_manual_introspection(const sd_bus_vtable vtable[]) {
+        struct introspect intro = {};
+        _cleanup_free_ char *s = NULL;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(introspect_begin(&intro, false) >= 0);
+
+        assert_se(introspect_write_interface(&intro, "org.foo", vtable) >= 0);
+        /* write again to check if output looks OK for a different interface */
+        assert_se(introspect_write_interface(&intro, "org.foo.bar", vtable) >= 0);
+        assert_se(introspect_finish(&intro, &s) == 0);
+
+        fputs(s, stdout);
+        fputs("\n", stdout);
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_DEBUG);
+
+        test_manual_introspection(test_vtable_1);
+        test_manual_introspection(test_vtable_2);
+        test_manual_introspection(test_vtable_deprecated);
+        test_manual_introspection((const sd_bus_vtable *) vtable_format_221);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-marshal.c b/src/libsystemd/sd-bus/test-bus-marshal.c
new file mode 100644
index 0000000..9feeaf4
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-marshal.c
@@ -0,0 +1,422 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <math.h>
+#include <stdlib.h>
+
+#if HAVE_GLIB
+#include <gio/gio.h>
+#endif
+
+#if HAVE_DBUS
+#include <dbus/dbus.h>
+#endif
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-dump.h"
+#include "bus-label.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "log.h"
+#include "tests.h"
+#include "util.h"
+
+static void test_bus_path_encode_unique(void) {
+        _cleanup_free_ char *a = NULL, *b = NULL, *c = NULL, *d = NULL, *e = NULL;
+
+        assert_se(bus_path_encode_unique(NULL, "/foo/bar", "some.sender", "a.suffix", &a) >= 0 && streq_ptr(a, "/foo/bar/some_2esender/a_2esuffix"));
+        assert_se(bus_path_decode_unique(a, "/foo/bar", &b, &c) > 0 && streq_ptr(b, "some.sender") && streq_ptr(c, "a.suffix"));
+        assert_se(bus_path_decode_unique(a, "/bar/foo", &d, &d) == 0 && !d);
+        assert_se(bus_path_decode_unique("/foo/bar/onlyOneSuffix", "/foo/bar", &d, &d) == 0 && !d);
+        assert_se(bus_path_decode_unique("/foo/bar/_/_", "/foo/bar", &d, &e) > 0 && streq_ptr(d, "") && streq_ptr(e, ""));
+}
+
+static void test_bus_path_encode(void) {
+        _cleanup_free_ char *a = NULL, *b = NULL, *c = NULL, *d = NULL, *e = NULL, *f = NULL;
+
+        assert_se(sd_bus_path_encode("/foo/bar", "waldo", &a) >= 0 && streq(a, "/foo/bar/waldo"));
+        assert_se(sd_bus_path_decode(a, "/waldo", &b) == 0 && b == NULL);
+        assert_se(sd_bus_path_decode(a, "/foo/bar", &b) > 0 && streq(b, "waldo"));
+
+        assert_se(sd_bus_path_encode("xxxx", "waldo", &c) < 0);
+        assert_se(sd_bus_path_encode("/foo/", "waldo", &c) < 0);
+
+        assert_se(sd_bus_path_encode("/foo/bar", "", &c) >= 0 && streq(c, "/foo/bar/_"));
+        assert_se(sd_bus_path_decode(c, "/foo/bar", &d) > 0 && streq(d, ""));
+
+        assert_se(sd_bus_path_encode("/foo/bar", "foo.bar", &e) >= 0 && streq(e, "/foo/bar/foo_2ebar"));
+        assert_se(sd_bus_path_decode(e, "/foo/bar", &f) > 0 && streq(f, "foo.bar"));
+}
+
+static void test_bus_path_encode_many(void) {
+        _cleanup_free_ char *a = NULL, *b = NULL, *c = NULL, *d = NULL, *e = NULL, *f = NULL;
+
+        assert_se(sd_bus_path_decode_many("/foo/bar", "/prefix/%", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/prefix/bar", "/prefix/%bar", NULL) == 1);
+        assert_se(sd_bus_path_decode_many("/foo/bar", "/prefix/%/suffix", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/prefix/foobar/suffix", "/prefix/%/suffix", &a) == 1 && streq_ptr(a, "foobar"));
+        assert_se(sd_bus_path_decode_many("/prefix/one_foo_two/mid/three_bar_four/suffix", "/prefix/one_%_two/mid/three_%_four/suffix", &b, &c) == 1 && streq_ptr(b, "foo") && streq_ptr(c, "bar"));
+        assert_se(sd_bus_path_decode_many("/prefix/one_foo_two/mid/three_bar_four/suffix", "/prefix/one_%_two/mid/three_%_four/suffix", NULL, &d) == 1 && streq_ptr(d, "bar"));
+
+        assert_se(sd_bus_path_decode_many("/foo/bar", "/foo/bar/%", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/bar%", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/%/bar", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/%bar", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/bar/suffix") == 1);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/%%/suffix", NULL, NULL) == 0); /* multiple '%' are treated verbatim */
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/%/suffi", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/%/suffix", &e) == 1 && streq_ptr(e, "bar"));
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/foo/%/%", NULL, NULL) == 1);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/%/%/%", NULL, NULL, NULL) == 1);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "%/%/%", NULL, NULL, NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/%/%", NULL, NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/%/%/", NULL, NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/%/", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "/%", NULL) == 0);
+        assert_se(sd_bus_path_decode_many("/foo/bar/suffix", "%", NULL) == 0);
+
+        assert_se(sd_bus_path_encode_many(&f, "/prefix/one_%_two/mid/three_%_four/suffix", "foo", "bar") >= 0 && streq_ptr(f, "/prefix/one_foo_two/mid/three_bar_four/suffix"));
+}
+
+static void test_bus_label_escape_one(const char *a, const char *b) {
+        _cleanup_free_ char *t = NULL, *x = NULL, *y = NULL;
+
+        assert_se(t = bus_label_escape(a));
+        assert_se(streq(t, b));
+
+        assert_se(x = bus_label_unescape(t));
+        assert_se(streq(a, x));
+
+        assert_se(y = bus_label_unescape(b));
+        assert_se(streq(a, y));
+}
+
+static void test_bus_label_escape(void) {
+        test_bus_label_escape_one("foo123bar", "foo123bar");
+        test_bus_label_escape_one("foo.bar", "foo_2ebar");
+        test_bus_label_escape_one("foo_2ebar", "foo_5f2ebar");
+        test_bus_label_escape_one("", "_");
+        test_bus_label_escape_one("_", "_5f");
+        test_bus_label_escape_one("1", "_31");
+        test_bus_label_escape_one(":1", "_3a1");
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *copy = NULL;
+        int r, boolean;
+        const char *x, *x2, *y, *z, *a, *b, *c, *d, *a_signature;
+        uint8_t u, v;
+        void *buffer = NULL;
+        size_t sz;
+        _cleanup_free_ char *h = NULL;
+        const int32_t integer_array[] = { -1, -2, 0, 1, 2 }, *return_array;
+        char *s;
+        _cleanup_free_ char *first = NULL, *second = NULL, *third = NULL;
+        _cleanup_fclose_ FILE *ms = NULL;
+        size_t first_size = 0, second_size = 0, third_size = 0;
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
+        double dbl;
+        uint64_t u64;
+
+        test_setup_logging(LOG_INFO);
+
+        r = sd_bus_default_user(&bus);
+        if (r < 0)
+                r = sd_bus_default_system(&bus);
+        if (r < 0)
+                return log_tests_skipped("Failed to connect to bus");
+
+        r = sd_bus_message_new_method_call(bus, &m, "foobar.waldo", "/", "foobar.waldo", "Piep");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "s", "a string");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "s", NULL);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "asg", 2, "string #1", "string #2", "sba(tt)ss");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "sass", "foobar", 5, "foo", "bar", "waldo", "piep", "pap", "after");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "a{yv}", 2, 3, "s", "foo", 5, "s", "waldo");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "y(ty)y(yt)y", 8, 777ULL, 7, 9, 77, 7777ULL, 10);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "()");
+        assert_se(r == -EINVAL);
+
+        r = sd_bus_message_append(m, "ba(ss)", 255, 3, "aaa", "1", "bbb", "2", "ccc", "3");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_open_container(m, 'a', "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append_basic(m, 's', "foobar");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append_basic(m, 's', "waldo");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_close_container(m);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append_string_space(m, 5, &s);
+        assert_se(r >= 0);
+        strcpy(s, "hallo");
+
+        r = sd_bus_message_append_array(m, 'i', integer_array, sizeof(integer_array));
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append_array(m, 'u', NULL, 0);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_append(m, "a(stdo)", 1, "foo", 815ULL, 47.0, "/");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_seal(m, 4711, 0);
+        assert_se(r >= 0);
+
+        sd_bus_message_dump(m, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        ms = open_memstream_unlocked(&first, &first_size);
+        sd_bus_message_dump(m, ms, 0);
+        fflush(ms);
+        assert_se(!ferror(ms));
+
+        r = bus_message_get_blob(m, &buffer, &sz);
+        assert_se(r >= 0);
+
+        h = cescape_length(buffer, sz);
+        assert_se(h);
+        log_info("message size = %zu, contents =\n%s", sz, h);
+
+#if HAVE_GLIB
+        /* Work-around for asan bug. See c8d980a3e962aba2ea3a4cedf75fa94890a6d746. */
+#if !HAS_FEATURE_ADDRESS_SANITIZER
+        {
+                GDBusMessage *g;
+                char *p;
+
+#if !defined(GLIB_VERSION_2_36)
+                g_type_init();
+#endif
+
+                g = g_dbus_message_new_from_blob(buffer, sz, 0, NULL);
+                p = g_dbus_message_print(g, 0);
+                log_info("%s", p);
+                g_free(p);
+                g_object_unref(g);
+        }
+#endif
+#endif
+
+#if HAVE_DBUS
+        {
+                DBusMessage *w;
+                DBusError error;
+
+                dbus_error_init(&error);
+
+                w = dbus_message_demarshal(buffer, sz, &error);
+                if (!w)
+                        log_error("%s", error.message);
+                else
+                        dbus_message_unref(w);
+
+                dbus_error_free(&error);
+        }
+#endif
+
+        m = sd_bus_message_unref(m);
+
+        r = bus_message_from_malloc(bus, buffer, sz, NULL, 0, NULL, &m);
+        assert_se(r >= 0);
+
+        sd_bus_message_dump(m, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        fclose(ms);
+        ms = open_memstream_unlocked(&second, &second_size);
+        sd_bus_message_dump(m, ms, 0);
+        fflush(ms);
+        assert_se(!ferror(ms));
+        assert_se(first_size == second_size);
+        assert_se(memcmp(first, second, first_size) == 0);
+
+        assert_se(sd_bus_message_rewind(m, true) >= 0);
+
+        r = sd_bus_message_read(m, "ssasg", &x, &x2, 2, &y, &z, &a_signature);
+        assert_se(r > 0);
+        assert_se(streq(x, "a string"));
+        assert_se(streq(x2, ""));
+        assert_se(streq(y, "string #1"));
+        assert_se(streq(z, "string #2"));
+        assert_se(streq(a_signature, "sba(tt)ss"));
+
+        r = sd_bus_message_read(m, "sass", &x, 5, &y, &z, &a, &b, &c, &d);
+        assert_se(r > 0);
+        assert_se(streq(x, "foobar"));
+        assert_se(streq(y, "foo"));
+        assert_se(streq(z, "bar"));
+        assert_se(streq(a, "waldo"));
+        assert_se(streq(b, "piep"));
+        assert_se(streq(c, "pap"));
+        assert_se(streq(d, "after"));
+
+        r = sd_bus_message_read(m, "a{yv}", 2, &u, "s", &x, &v, "s", &y);
+        assert_se(r > 0);
+        assert_se(u == 3);
+        assert_se(streq(x, "foo"));
+        assert_se(v == 5);
+        assert_se(streq(y, "waldo"));
+
+        r = sd_bus_message_read(m, "y(ty)", &v, &u64, &u);
+        assert_se(r > 0);
+        assert_se(v == 8);
+        assert_se(u64 == 777);
+        assert_se(u == 7);
+
+        r = sd_bus_message_read(m, "y(yt)", &v, &u, &u64);
+        assert_se(r > 0);
+        assert_se(v == 9);
+        assert_se(u == 77);
+        assert_se(u64 == 7777);
+
+        r = sd_bus_message_read(m, "y", &v);
+        assert_se(r > 0);
+        assert_se(v == 10);
+
+        r = sd_bus_message_read(m, "()");
+        assert_se(r < 0);
+
+        r = sd_bus_message_read(m, "ba(ss)", &boolean, 3, &x, &y, &a, &b, &c, &d);
+        assert_se(r > 0);
+        assert_se(boolean);
+        assert_se(streq(x, "aaa"));
+        assert_se(streq(y, "1"));
+        assert_se(streq(a, "bbb"));
+        assert_se(streq(b, "2"));
+        assert_se(streq(c, "ccc"));
+        assert_se(streq(d, "3"));
+
+        assert_se(sd_bus_message_verify_type(m, 'a', "s") > 0);
+
+        r = sd_bus_message_read(m, "as", 2, &x, &y);
+        assert_se(r > 0);
+        assert_se(streq(x, "foobar"));
+        assert_se(streq(y, "waldo"));
+
+        r = sd_bus_message_read_basic(m, 's', &s);
+        assert_se(r > 0);
+        assert_se(streq(s, "hallo"));
+
+        r = sd_bus_message_read_array(m, 'i', (const void**) &return_array, &sz);
+        assert_se(r > 0);
+        assert_se(sz == sizeof(integer_array));
+        assert_se(memcmp(integer_array, return_array, sz) == 0);
+
+        r = sd_bus_message_read_array(m, 'u', (const void**) &return_array, &sz);
+        assert_se(r > 0);
+        assert_se(sz == 0);
+
+        r = sd_bus_message_read(m, "a(stdo)", 1, &x, &u64, &dbl, &y);
+        assert_se(r > 0);
+        assert_se(streq(x, "foo"));
+        assert_se(u64 == 815ULL);
+        assert_se(fabs(dbl - 47.0) < 0.1);
+        assert_se(streq(y, "/"));
+
+        r = sd_bus_message_peek_type(m, NULL, NULL);
+        assert_se(r == 0);
+
+        r = sd_bus_message_new_method_call(bus, &copy, "foobar.waldo", "/", "foobar.waldo", "Piep");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_rewind(m, true);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_copy(copy, m, true);
+        assert_se(r >= 0);
+
+        r = sd_bus_message_seal(copy, 4712, 0);
+        assert_se(r >= 0);
+
+        fclose(ms);
+        ms = open_memstream_unlocked(&third, &third_size);
+        sd_bus_message_dump(copy, ms, 0);
+        fflush(ms);
+        assert_se(!ferror(ms));
+
+        printf("<%.*s>\n", (int) first_size, first);
+        printf("<%.*s>\n", (int) third_size, third);
+
+        assert_se(first_size == third_size);
+        assert_se(memcmp(first, third, third_size) == 0);
+
+        r = sd_bus_message_rewind(m, true);
+        assert_se(r >= 0);
+
+        assert_se(sd_bus_message_verify_type(m, 's', NULL) > 0);
+
+        r = sd_bus_message_skip(m, "ssasg");
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_verify_type(m, 's', NULL) > 0);
+
+        r = sd_bus_message_skip(m, "sass");
+        assert_se(r >= 0);
+
+        assert_se(sd_bus_message_verify_type(m, 'a', "{yv}") > 0);
+
+        r = sd_bus_message_skip(m, "a{yv}y(ty)y(yt)y");
+        assert_se(r >= 0);
+
+        assert_se(sd_bus_message_verify_type(m, 'b', NULL) > 0);
+
+        r = sd_bus_message_read(m, "b", &boolean);
+        assert_se(r > 0);
+        assert_se(boolean);
+
+        r = sd_bus_message_enter_container(m, 0, NULL);
+        assert_se(r > 0);
+
+        r = sd_bus_message_read(m, "(ss)", &x, &y);
+        assert_se(r > 0);
+
+        r = sd_bus_message_read(m, "(ss)", &a, &b);
+        assert_se(r > 0);
+
+        r = sd_bus_message_read(m, "(ss)", &c, &d);
+        assert_se(r > 0);
+
+        r = sd_bus_message_read(m, "(ss)", &x, &y);
+        assert_se(r == 0);
+
+        r = sd_bus_message_exit_container(m);
+        assert_se(r >= 0);
+
+        assert_se(streq(x, "aaa"));
+        assert_se(streq(y, "1"));
+        assert_se(streq(a, "bbb"));
+        assert_se(streq(b, "2"));
+        assert_se(streq(c, "ccc"));
+        assert_se(streq(d, "3"));
+
+        test_bus_label_escape();
+        test_bus_path_encode();
+        test_bus_path_encode_unique();
+        test_bus_path_encode_many();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-match.c b/src/libsystemd/sd-bus/test-bus-match.c
new file mode 100644
index 0000000..aa6ddd3
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-match.c
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-match.h"
+#include "bus-message.h"
+#include "bus-slot.h"
+#include "bus-util.h"
+#include "log.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "tests.h"
+
+static bool mask[32];
+
+static int filter(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        log_info("Ran %u", PTR_TO_UINT(userdata));
+        assert_se(PTR_TO_UINT(userdata) < ELEMENTSOF(mask));
+        mask[PTR_TO_UINT(userdata)] = true;
+        return 0;
+}
+
+static bool mask_contains(unsigned a[], unsigned n) {
+        unsigned i, j;
+
+        for (i = 0; i < ELEMENTSOF(mask); i++) {
+                bool found = false;
+
+                for (j = 0; j < n; j++)
+                        if (a[j] == i) {
+                                found = true;
+                                break;
+                        }
+
+                if (found != mask[i])
+                        return false;
+        }
+
+        return true;
+}
+
+static int match_add(sd_bus_slot *slots, struct bus_match_node *root, const char *match, int value) {
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+        sd_bus_slot *s;
+        int r;
+
+        s = slots + value;
+        zero(*s);
+
+        r = bus_match_parse(match, &components, &n_components);
+        if (r < 0)
+                return r;
+
+        s->userdata = INT_TO_PTR(value);
+        s->match_callback.callback = filter;
+
+        r = bus_match_add(root, components, n_components, &s->match_callback);
+        bus_match_parse_free(components, n_components);
+
+        return r;
+}
+
+static void test_match_scope(const char *match, enum bus_match_scope scope) {
+        struct bus_match_component *components = NULL;
+        unsigned n_components = 0;
+
+        assert_se(bus_match_parse(match, &components, &n_components) >= 0);
+        assert_se(bus_match_get_scope(components, n_components) == scope);
+        bus_match_parse_free(components, n_components);
+}
+
+int main(int argc, char *argv[]) {
+        struct bus_match_node root = {
+                .type = BUS_MATCH_ROOT,
+        };
+
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        enum bus_match_node_type i;
+        sd_bus_slot slots[19];
+        int r;
+
+        test_setup_logging(LOG_INFO);
+
+        r = sd_bus_open_user(&bus);
+        if (r < 0)
+                r = sd_bus_open_system(&bus);
+        if (r < 0)
+                return log_tests_skipped("Failed to connect to bus");
+
+        assert_se(match_add(slots, &root, "arg2='wal\\'do',sender='foo',type='signal',interface='bar.x',", 1) >= 0);
+        assert_se(match_add(slots, &root, "arg2='wal\\'do2',sender='foo',type='signal',interface='bar.x',", 2) >= 0);
+        assert_se(match_add(slots, &root, "arg3='test',sender='foo',type='signal',interface='bar.x',", 3) >= 0);
+        assert_se(match_add(slots, &root, "arg3='test',sender='foo',type='method_call',interface='bar.x',", 4) >= 0);
+        assert_se(match_add(slots, &root, "", 5) >= 0);
+        assert_se(match_add(slots, &root, "interface='quux.x'", 6) >= 0);
+        assert_se(match_add(slots, &root, "interface='bar.x'", 7) >= 0);
+        assert_se(match_add(slots, &root, "member='waldo',path='/foo/bar'", 8) >= 0);
+        assert_se(match_add(slots, &root, "path='/foo/bar'", 9) >= 0);
+        assert_se(match_add(slots, &root, "path_namespace='/foo'", 10) >= 0);
+        assert_se(match_add(slots, &root, "path_namespace='/foo/quux'", 11) >= 0);
+        assert_se(match_add(slots, &root, "arg1='two'", 12) >= 0);
+        assert_se(match_add(slots, &root, "member='waldo',arg2path='/prefix/'", 13) >= 0);
+        assert_se(match_add(slots, &root, "member=waldo,path='/foo/bar',arg3namespace='prefix'", 14) >= 0);
+        assert_se(match_add(slots, &root, "arg4has='pi'", 15) >= 0);
+        assert_se(match_add(slots, &root, "arg4has='pa'", 16) >= 0);
+        assert_se(match_add(slots, &root, "arg4has='po'", 17) >= 0);
+        assert_se(match_add(slots, &root, "arg4='pi'", 18) >= 0);
+
+        bus_match_dump(&root, 0);
+
+        assert_se(sd_bus_message_new_signal(bus, &m, "/foo/bar", "bar.x", "waldo") >= 0);
+        assert_se(sd_bus_message_append(m, "ssssas", "one", "two", "/prefix/three", "prefix.four", 3, "pi", "pa", "po") >= 0);
+        assert_se(sd_bus_message_seal(m, 1, 0) >= 0);
+
+        zero(mask);
+        assert_se(bus_match_run(NULL, &root, m) == 0);
+        assert_se(mask_contains((unsigned[]) { 9, 8, 7, 5, 10, 12, 13, 14, 15, 16, 17 }, 11));
+
+        assert_se(bus_match_remove(&root, &slots[8].match_callback) >= 0);
+        assert_se(bus_match_remove(&root, &slots[13].match_callback) >= 0);
+
+        bus_match_dump(&root, 0);
+
+        zero(mask);
+        assert_se(bus_match_run(NULL, &root, m) == 0);
+        assert_se(mask_contains((unsigned[]) { 9, 5, 10, 12, 14, 7, 15, 16, 17 }, 9));
+
+        for (i = 0; i < _BUS_MATCH_NODE_TYPE_MAX; i++) {
+                char buf[32];
+                const char *x;
+
+                assert_se(x = bus_match_node_type_to_string(i, buf, sizeof(buf)));
+
+                if (i >= BUS_MATCH_MESSAGE_TYPE)
+                        assert_se(bus_match_node_type_from_string(x, strlen(x)) == i);
+        }
+
+        bus_match_free(&root);
+
+        test_match_scope("interface='foobar'", BUS_MATCH_GENERIC);
+        test_match_scope("", BUS_MATCH_GENERIC);
+        test_match_scope("interface='org.freedesktop.DBus.Local'", BUS_MATCH_LOCAL);
+        test_match_scope("sender='org.freedesktop.DBus.Local'", BUS_MATCH_LOCAL);
+        test_match_scope("member='gurke',path='/org/freedesktop/DBus/Local'", BUS_MATCH_LOCAL);
+        test_match_scope("arg2='piep',sender='org.freedesktop.DBus',member='waldo'", BUS_MATCH_DRIVER);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-objects.c b/src/libsystemd/sd-bus/test-bus-objects.c
new file mode 100644
index 0000000..9116211
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-objects.c
@@ -0,0 +1,536 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <pthread.h>
+#include <stdlib.h>
+
+#include "sd-bus.h"
+
+#include "alloc-util.h"
+#include "bus-dump.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "log.h"
+#include "macro.h"
+#include "strv.h"
+#include "util.h"
+
+struct context {
+        int fds[2];
+        bool quit;
+        char *something;
+        char *automatic_string_property;
+        uint32_t automatic_integer_property;
+};
+
+static int something_handler(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        struct context *c = userdata;
+        const char *s;
+        char *n = NULL;
+        int r;
+
+        r = sd_bus_message_read(m, "s", &s);
+        assert_se(r > 0);
+
+        n = strjoin("<<<", s, ">>>");
+        assert_se(n);
+
+        free(c->something);
+        c->something = n;
+
+        log_info("AlterSomething() called, got %s, returning %s", s, n);
+
+        /* This should fail, since the return type doesn't match */
+        assert_se(sd_bus_reply_method_return(m, "u", 4711) == -ENOMSG);
+
+        r = sd_bus_reply_method_return(m, "s", n);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int exit_handler(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        struct context *c = userdata;
+        int r;
+
+        c->quit = true;
+
+        log_info("Exit called");
+
+        r = sd_bus_reply_method_return(m, "");
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int get_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+        struct context *c = userdata;
+        int r;
+
+        log_info("property get for %s called, returning \"%s\".", property, c->something);
+
+        r = sd_bus_message_append(reply, "s", c->something);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int set_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *value, void *userdata, sd_bus_error *error) {
+        struct context *c = userdata;
+        const char *s;
+        char *n;
+        int r;
+
+        log_info("property set for %s called", property);
+
+        r = sd_bus_message_read(value, "s", &s);
+        assert_se(r >= 0);
+
+        n = strdup(s);
+        assert_se(n);
+
+        free(c->something);
+        c->something = n;
+
+        return 1;
+}
+
+static int value_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+        _cleanup_free_ char *s = NULL;
+        const char *x;
+        int r;
+
+        assert_se(asprintf(&s, "object %p, path %s", userdata, path) >= 0);
+        r = sd_bus_message_append(reply, "s", s);
+        assert_se(r >= 0);
+
+        assert_se(x = startswith(path, "/value/"));
+
+        assert_se(PTR_TO_UINT(userdata) == 30);
+
+        return 1;
+}
+
+static int notify_test(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        int r;
+
+        assert_se(sd_bus_emit_properties_changed(sd_bus_message_get_bus(m), m->path, "org.freedesktop.systemd.ValueTest", "Value", NULL) >= 0);
+
+        r = sd_bus_reply_method_return(m, NULL);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int notify_test2(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        int r;
+
+        assert_se(sd_bus_emit_properties_changed_strv(sd_bus_message_get_bus(m), m->path, "org.freedesktop.systemd.ValueTest", NULL) >= 0);
+
+        r = sd_bus_reply_method_return(m, NULL);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int emit_interfaces_added(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        int r;
+
+        assert_se(sd_bus_emit_interfaces_added(sd_bus_message_get_bus(m), "/value/a/x", "org.freedesktop.systemd.ValueTest", NULL) >= 0);
+
+        r = sd_bus_reply_method_return(m, NULL);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int emit_interfaces_removed(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        int r;
+
+        assert_se(sd_bus_emit_interfaces_removed(sd_bus_message_get_bus(m), "/value/a/x", "org.freedesktop.systemd.ValueTest", NULL) >= 0);
+
+        r = sd_bus_reply_method_return(m, NULL);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int emit_object_added(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        int r;
+
+        assert_se(sd_bus_emit_object_added(sd_bus_message_get_bus(m), "/value/a/x") >= 0);
+
+        r = sd_bus_reply_method_return(m, NULL);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static int emit_object_removed(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        int r;
+
+        assert_se(sd_bus_emit_object_removed(sd_bus_message_get_bus(m), "/value/a/x") >= 0);
+
+        r = sd_bus_reply_method_return(m, NULL);
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static const sd_bus_vtable vtable[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("AlterSomething", "s", "s", something_handler, 0),
+        SD_BUS_METHOD("Exit", "", "", exit_handler, 0),
+        SD_BUS_WRITABLE_PROPERTY("Something", "s", get_handler, set_handler, 0, 0),
+        SD_BUS_WRITABLE_PROPERTY("AutomaticStringProperty", "s", NULL, NULL, offsetof(struct context, automatic_string_property), 0),
+        SD_BUS_WRITABLE_PROPERTY("AutomaticIntegerProperty", "u", NULL, NULL, offsetof(struct context, automatic_integer_property), 0),
+        SD_BUS_METHOD("NoOperation", NULL, NULL, NULL, 0),
+        SD_BUS_METHOD("EmitInterfacesAdded", NULL, NULL, emit_interfaces_added, 0),
+        SD_BUS_METHOD("EmitInterfacesRemoved", NULL, NULL, emit_interfaces_removed, 0),
+        SD_BUS_METHOD("EmitObjectAdded", NULL, NULL, emit_object_added, 0),
+        SD_BUS_METHOD("EmitObjectRemoved", NULL, NULL, emit_object_removed, 0),
+        SD_BUS_VTABLE_END
+};
+
+static const sd_bus_vtable vtable2[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("NotifyTest", "", "", notify_test, 0),
+        SD_BUS_METHOD("NotifyTest2", "", "", notify_test2, 0),
+        SD_BUS_PROPERTY("Value", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+        SD_BUS_PROPERTY("Value2", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
+        SD_BUS_PROPERTY("Value3", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("Value4", "s", value_handler, 10, 0),
+        SD_BUS_PROPERTY("AnExplicitProperty", "s", NULL, offsetof(struct context, something), SD_BUS_VTABLE_PROPERTY_EXPLICIT|SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
+        SD_BUS_VTABLE_END
+};
+
+static int enumerator_callback(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
+
+        if (object_path_startswith("/value", path))
+                assert_se(*nodes = strv_new("/value/a", "/value/b", "/value/c"));
+
+        return 1;
+}
+
+static int enumerator2_callback(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error) {
+
+        if (object_path_startswith("/value/a", path))
+                assert_se(*nodes = strv_new("/value/a/x", "/value/a/y", "/value/a/z"));
+
+        return 1;
+}
+
+static void *server(void *p) {
+        struct context *c = p;
+        sd_bus *bus = NULL;
+        sd_id128_t id;
+        int r;
+
+        c->quit = false;
+
+        assert_se(sd_id128_randomize(&id) >= 0);
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_fd(bus, c->fds[0], c->fds[0]) >= 0);
+        assert_se(sd_bus_set_server(bus, 1, id) >= 0);
+
+        assert_se(sd_bus_add_object_vtable(bus, NULL, "/foo", "org.freedesktop.systemd.test", vtable, c) >= 0);
+        assert_se(sd_bus_add_object_vtable(bus, NULL, "/foo", "org.freedesktop.systemd.test2", vtable, c) >= 0);
+        assert_se(sd_bus_add_fallback_vtable(bus, NULL, "/value", "org.freedesktop.systemd.ValueTest", vtable2, NULL, UINT_TO_PTR(20)) >= 0);
+        assert_se(sd_bus_add_node_enumerator(bus, NULL, "/value", enumerator_callback, NULL) >= 0);
+        assert_se(sd_bus_add_node_enumerator(bus, NULL, "/value/a", enumerator2_callback, NULL) >= 0);
+        assert_se(sd_bus_add_object_manager(bus, NULL, "/value") >= 0);
+        assert_se(sd_bus_add_object_manager(bus, NULL, "/value/a") >= 0);
+
+        assert_se(sd_bus_start(bus) >= 0);
+
+        log_error("Entering event loop on server");
+
+        while (!c->quit) {
+                log_error("Loop!");
+
+                r = sd_bus_process(bus, NULL);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to process requests: %m");
+                        goto fail;
+                }
+
+                if (r == 0) {
+                        r = sd_bus_wait(bus, (uint64_t) -1);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to wait: %m");
+                                goto fail;
+                        }
+
+                        continue;
+                }
+        }
+
+        r = 0;
+
+fail:
+        if (bus) {
+                sd_bus_flush(bus);
+                sd_bus_unref(bus);
+        }
+
+        return INT_TO_PTR(r);
+}
+
+static int client(struct context *c) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        const char *s;
+        int r;
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_fd(bus, c->fds[1], c->fds[1]) >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "NoOperation", &error, NULL, NULL);
+        assert_se(r >= 0);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "AlterSomething", &error, &reply, "s", "hallo");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        assert_se(streq(s, "<<<hallo>>>"));
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Doesntexist", &error, &reply, "");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD));
+
+        sd_bus_error_free(&error);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "AlterSomething", &error, &reply, "as", 1, "hallo");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_INVALID_ARGS));
+
+        sd_bus_error_free(&error);
+
+        r = sd_bus_get_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Something", &error, &reply, "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        assert_se(streq(s, "<<<hallo>>>"));
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_set_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Something", &error, "s", "test");
+        assert_se(r >= 0);
+
+        r = sd_bus_get_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Something", &error, &reply, "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        assert_se(streq(s, "test"));
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_set_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "AutomaticIntegerProperty", &error, "u", 815);
+        assert_se(r >= 0);
+
+        assert_se(c->automatic_integer_property == 815);
+
+        r = sd_bus_set_property(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "AutomaticStringProperty", &error, "s", "Du Dödel, Du!");
+        assert_se(r >= 0);
+
+        assert_se(streq(c->automatic_string_property, "Du Dödel, Du!"));
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_get_property(bus, "org.freedesktop.systemd.test", "/value/xuzz", "org.freedesktop.systemd.ValueTest", "Value", &error, &reply, "s");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        log_info("read %s", s);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value/a", "org.freedesktop.DBus.Introspectable", "Introspect", &error, &reply, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_message_read(reply, "s", &s);
+        assert_se(r >= 0);
+        fputs(s, stdout);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.DBus.Properties", "GetAll", &error, &reply, "s", "");
+        assert_se(r >= 0);
+
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value/a", "org.freedesktop.DBus.Properties", "GetAll", &error, &reply, "s", "org.freedesktop.systemd.ValueTest2");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_INTERFACE));
+        sd_bus_error_free(&error);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.DBus.ObjectManager", "GetManagedObjects", &error, &reply, "");
+        assert_se(r < 0);
+        assert_se(sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD));
+        sd_bus_error_free(&error);
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value", "org.freedesktop.DBus.ObjectManager", "GetManagedObjects", &error, &reply, "");
+        assert_se(r >= 0);
+
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value/a", "org.freedesktop.systemd.ValueTest", "NotifyTest", &error, NULL, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_process(bus, &reply);
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_is_signal(reply, "org.freedesktop.DBus.Properties", "PropertiesChanged"));
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/value/a", "org.freedesktop.systemd.ValueTest", "NotifyTest2", &error, NULL, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_process(bus, &reply);
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_is_signal(reply, "org.freedesktop.DBus.Properties", "PropertiesChanged"));
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "EmitInterfacesAdded", &error, NULL, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_process(bus, &reply);
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_is_signal(reply, "org.freedesktop.DBus.ObjectManager", "InterfacesAdded"));
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "EmitInterfacesRemoved", &error, NULL, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_process(bus, &reply);
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_is_signal(reply, "org.freedesktop.DBus.ObjectManager", "InterfacesRemoved"));
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "EmitObjectAdded", &error, NULL, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_process(bus, &reply);
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_is_signal(reply, "org.freedesktop.DBus.ObjectManager", "InterfacesAdded"));
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "EmitObjectRemoved", &error, NULL, "");
+        assert_se(r >= 0);
+
+        r = sd_bus_process(bus, &reply);
+        assert_se(r > 0);
+
+        assert_se(sd_bus_message_is_signal(reply, "org.freedesktop.DBus.ObjectManager", "InterfacesRemoved"));
+        sd_bus_message_dump(reply, stdout, SD_BUS_MESSAGE_DUMP_WITH_HEADER);
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+
+        r = sd_bus_call_method(bus, "org.freedesktop.systemd.test", "/foo", "org.freedesktop.systemd.test", "Exit", &error, NULL, "");
+        assert_se(r >= 0);
+
+        sd_bus_flush(bus);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        struct context c = {};
+        pthread_t s;
+        void *p;
+        int r, q;
+
+        c.automatic_integer_property = 4711;
+        assert_se(c.automatic_string_property = strdup("dudeldu"));
+
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, c.fds) >= 0);
+
+        r = pthread_create(&s, NULL, server, &c);
+        if (r != 0)
+                return -r;
+
+        r = client(&c);
+
+        q = pthread_join(s, &p);
+        if (q != 0)
+                return -q;
+
+        if (r < 0)
+                return r;
+
+        if (PTR_TO_INT(p) < 0)
+                return PTR_TO_INT(p);
+
+        free(c.something);
+        free(c.automatic_string_property);
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c b/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c
new file mode 100644
index 0000000..7c2fa72
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#include "sd-bus.h"
+
+#include "main-func.h"
+#include "tests.h"
+
+static int test_ref_unref(void) {
+        sd_bus_message *m = NULL;
+        sd_bus *bus = NULL;
+        int r;
+
+        /* This test will result in a memory leak in <= v240, but not on v241. Hence to be really useful it
+         * should be run through a leak tracker such as valgrind. */
+
+        r = sd_bus_open_system(&bus);
+        if (r < 0)
+                return log_tests_skipped("Failed to connect to bus");
+
+        /* Create a message and enqueue it (this shouldn't send it though as the connection setup is not complete yet) */
+        assert_se(sd_bus_message_new_method_call(bus, &m, "foo.bar", "/foo", "quux.quux", "waldo") >= 0);
+        assert_se(sd_bus_send(bus, m, NULL) >= 0);
+
+        /* Let's now unref the message first and the bus second. */
+        m = sd_bus_message_unref(m);
+        bus = sd_bus_unref(bus);
+
+        /* We should have a memory leak now on <= v240. Let's do this again, but destroy in the opposite
+         * order. On v240 that too should be a leak. */
+
+        r = sd_bus_open_system(&bus);
+        if (r < 0)
+                return log_tests_skipped("Failed to connect to bus");
+
+        assert_se(sd_bus_message_new_method_call(bus, &m, "foo.bar", "/foo", "quux.quux", "waldo") >= 0);
+        assert_se(sd_bus_send(bus, m, NULL) >= 0);
+
+        /* Let's now unref things in the opposite order */
+        bus = sd_bus_unref(bus);
+        m = sd_bus_message_unref(m);
+
+        return 0;
+}
+
+static int run(int argc, char *argv[]) {
+        int r;
+
+        test_setup_logging(LOG_INFO);
+
+        r = test_ref_unref();
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+DEFINE_MAIN_FUNCTION(run);
diff --git a/src/libsystemd/sd-bus/test-bus-server.c b/src/libsystemd/sd-bus/test-bus-server.c
new file mode 100644
index 0000000..5cb100b
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-server.c
@@ -0,0 +1,198 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <pthread.h>
+#include <stdlib.h>
+
+#include "sd-bus.h"
+
+#include "bus-internal.h"
+#include "bus-util.h"
+#include "log.h"
+#include "macro.h"
+#include "memory-util.h"
+
+struct context {
+        int fds[2];
+
+        bool client_negotiate_unix_fds;
+        bool server_negotiate_unix_fds;
+
+        bool client_anonymous_auth;
+        bool server_anonymous_auth;
+};
+
+static void *server(void *p) {
+        struct context *c = p;
+        sd_bus *bus = NULL;
+        sd_id128_t id;
+        bool quit = false;
+        int r;
+
+        assert_se(sd_id128_randomize(&id) >= 0);
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_fd(bus, c->fds[0], c->fds[0]) >= 0);
+        assert_se(sd_bus_set_server(bus, 1, id) >= 0);
+        assert_se(sd_bus_set_anonymous(bus, c->server_anonymous_auth) >= 0);
+        assert_se(sd_bus_negotiate_fds(bus, c->server_negotiate_unix_fds) >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        while (!quit) {
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
+
+                r = sd_bus_process(bus, &m);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to process requests: %m");
+                        goto fail;
+                }
+
+                if (r == 0) {
+                        r = sd_bus_wait(bus, (uint64_t) -1);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to wait: %m");
+                                goto fail;
+                        }
+
+                        continue;
+                }
+
+                if (!m)
+                        continue;
+
+                log_info("Got message! member=%s", strna(sd_bus_message_get_member(m)));
+
+                if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "Exit")) {
+
+                        assert_se((sd_bus_can_send(bus, 'h') >= 1) ==
+                                  (c->server_negotiate_unix_fds && c->client_negotiate_unix_fds));
+
+                        r = sd_bus_message_new_method_return(m, &reply);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to allocate return: %m");
+                                goto fail;
+                        }
+
+                        quit = true;
+
+                } else if (sd_bus_message_is_method_call(m, NULL, NULL)) {
+                        r = sd_bus_message_new_method_error(
+                                        m,
+                                        &reply,
+                                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_UNKNOWN_METHOD, "Unknown method."));
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to allocate return: %m");
+                                goto fail;
+                        }
+                }
+
+                if (reply) {
+                        r = sd_bus_send(bus, reply, NULL);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to send reply: %m");
+                                goto fail;
+                        }
+                }
+        }
+
+        r = 0;
+
+fail:
+        if (bus) {
+                sd_bus_flush(bus);
+                sd_bus_unref(bus);
+        }
+
+        return INT_TO_PTR(r);
+}
+
+static int client(struct context *c) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        int r;
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_fd(bus, c->fds[1], c->fds[1]) >= 0);
+        assert_se(sd_bus_negotiate_fds(bus, c->client_negotiate_unix_fds) >= 0);
+        assert_se(sd_bus_set_anonymous(bus, c->client_anonymous_auth) >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        &m,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.systemd.test",
+                        "Exit");
+        if (r < 0)
+                return log_error_errno(r, "Failed to allocate method call: %m");
+
+        r = sd_bus_call(bus, m, 0, &error, &reply);
+        if (r < 0)
+                return log_error_errno(r, "Failed to issue method call: %s", bus_error_message(&error, r));
+
+        return 0;
+}
+
+static int test_one(bool client_negotiate_unix_fds, bool server_negotiate_unix_fds,
+                    bool client_anonymous_auth, bool server_anonymous_auth) {
+
+        struct context c;
+        pthread_t s;
+        void *p;
+        int r, q;
+
+        zero(c);
+
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, c.fds) >= 0);
+
+        c.client_negotiate_unix_fds = client_negotiate_unix_fds;
+        c.server_negotiate_unix_fds = server_negotiate_unix_fds;
+        c.client_anonymous_auth = client_anonymous_auth;
+        c.server_anonymous_auth = server_anonymous_auth;
+
+        r = pthread_create(&s, NULL, server, &c);
+        if (r != 0)
+                return -r;
+
+        r = client(&c);
+
+        q = pthread_join(s, &p);
+        if (q != 0)
+                return -q;
+
+        if (r < 0)
+                return r;
+
+        if (PTR_TO_INT(p) < 0)
+                return PTR_TO_INT(p);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        int r;
+
+        r = test_one(true, true, false, false);
+        assert_se(r >= 0);
+
+        r = test_one(true, false, false, false);
+        assert_se(r >= 0);
+
+        r = test_one(false, true, false, false);
+        assert_se(r >= 0);
+
+        r = test_one(false, false, false, false);
+        assert_se(r >= 0);
+
+        r = test_one(true, true, true, true);
+        assert_se(r >= 0);
+
+        r = test_one(true, true, false, true);
+        assert_se(r >= 0);
+
+        r = test_one(true, true, true, false);
+        assert_se(r == -EPERM);
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-signature.c b/src/libsystemd/sd-bus/test-bus-signature.c
new file mode 100644
index 0000000..ea7efe6
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-signature.c
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-internal.h"
+#include "bus-signature.h"
+#include "log.h"
+#include "string-util.h"
+
+int main(int argc, char *argv[]) {
+        char prefix[256];
+        int r;
+
+        assert_se(signature_is_single("y", false));
+        assert_se(signature_is_single("u", false));
+        assert_se(signature_is_single("v", false));
+        assert_se(signature_is_single("as", false));
+        assert_se(signature_is_single("(ss)", false));
+        assert_se(!signature_is_single("()", false));
+        assert_se(!signature_is_single("(()()()()())", false));
+        assert_se(!signature_is_single("(((())))", false));
+        assert_se(signature_is_single("((((s))))", false));
+        assert_se(signature_is_single("{ss}", true));
+        assert_se(signature_is_single("a{ss}", false));
+        assert_se(!signature_is_single("uu", false));
+        assert_se(!signature_is_single("", false));
+        assert_se(!signature_is_single("(", false));
+        assert_se(!signature_is_single(")", false));
+        assert_se(!signature_is_single("())", false));
+        assert_se(!signature_is_single("((())", false));
+        assert_se(!signature_is_single("{)", false));
+        assert_se(!signature_is_single("{}", true));
+        assert_se(!signature_is_single("{sss}", true));
+        assert_se(!signature_is_single("{s}", true));
+        assert_se(!signature_is_single("{ss}", false));
+        assert_se(!signature_is_single("{ass}", true));
+        assert_se(!signature_is_single("a}", true));
+
+        assert_se(signature_is_pair("yy"));
+        assert_se(signature_is_pair("ss"));
+        assert_se(signature_is_pair("sas"));
+        assert_se(signature_is_pair("sv"));
+        assert_se(signature_is_pair("sa(vs)"));
+        assert_se(!signature_is_pair(""));
+        assert_se(!signature_is_pair("va"));
+        assert_se(!signature_is_pair("sss"));
+        assert_se(!signature_is_pair("{s}ss"));
+
+        assert_se(signature_is_valid("ssa{ss}sssub", true));
+        assert_se(signature_is_valid("ssa{ss}sssub", false));
+        assert_se(signature_is_valid("{ss}", true));
+        assert_se(!signature_is_valid("{ss}", false));
+        assert_se(signature_is_valid("", true));
+        assert_se(signature_is_valid("", false));
+
+        assert_se(signature_is_valid("sssusa(uuubbba(uu)uuuu)a{u(uuuvas)}", false));
+
+        assert_se(!signature_is_valid("a", false));
+        assert_se(signature_is_valid("as", false));
+        assert_se(signature_is_valid("aas", false));
+        assert_se(signature_is_valid("aaas", false));
+        assert_se(signature_is_valid("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaad", false));
+        assert_se(signature_is_valid("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaas", false));
+        assert_se(!signature_is_valid("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaau", false));
+
+        assert_se(signature_is_valid("((((((((((((((((((((((((((((((((s))))))))))))))))))))))))))))))))", false));
+        assert_se(!signature_is_valid("((((((((((((((((((((((((((((((((()))))))))))))))))))))))))))))))))", false));
+
+        assert_se(namespace_complex_pattern("", ""));
+        assert_se(namespace_complex_pattern("foobar", "foobar"));
+        assert_se(namespace_complex_pattern("foobar.waldo", "foobar.waldo"));
+        assert_se(namespace_complex_pattern("foobar.", "foobar.waldo"));
+        assert_se(namespace_complex_pattern("foobar.waldo", "foobar."));
+        assert_se(!namespace_complex_pattern("foobar.waldo", "foobar"));
+        assert_se(!namespace_complex_pattern("foobar", "foobar.waldo"));
+        assert_se(!namespace_complex_pattern("", "foo"));
+        assert_se(!namespace_complex_pattern("foo", ""));
+        assert_se(!namespace_complex_pattern("foo.", ""));
+
+        assert_se(path_complex_pattern("", ""));
+        assert_se(!path_complex_pattern("", "/"));
+        assert_se(!path_complex_pattern("/", ""));
+        assert_se(path_complex_pattern("/", "/"));
+        assert_se(path_complex_pattern("/foobar/", "/"));
+        assert_se(!path_complex_pattern("/foobar/", "/foobar"));
+        assert_se(path_complex_pattern("/foobar", "/foobar"));
+        assert_se(!path_complex_pattern("/foobar", "/foobar/"));
+        assert_se(!path_complex_pattern("/foobar", "/foobar/waldo"));
+        assert_se(path_complex_pattern("/foobar/", "/foobar/waldo"));
+        assert_se(path_complex_pattern("/foobar/waldo", "/foobar/"));
+
+        assert_se(path_simple_pattern("/foo/", "/foo/bar/waldo"));
+
+        assert_se(namespace_simple_pattern("", ""));
+        assert_se(namespace_simple_pattern("", ".foobar"));
+        assert_se(namespace_simple_pattern("foobar", "foobar"));
+        assert_se(namespace_simple_pattern("foobar.waldo", "foobar.waldo"));
+        assert_se(namespace_simple_pattern("foobar", "foobar.waldo"));
+        assert_se(!namespace_simple_pattern("foobar.waldo", "foobar"));
+        assert_se(!namespace_simple_pattern("", "foo"));
+        assert_se(!namespace_simple_pattern("foo", ""));
+        assert_se(namespace_simple_pattern("foo.", "foo.bar.waldo"));
+
+        assert_se(streq(object_path_startswith("/foo/bar", "/foo"), "bar"));
+        assert_se(streq(object_path_startswith("/foo", "/foo"), ""));
+        assert_se(streq(object_path_startswith("/foo", "/"), "foo"));
+        assert_se(streq(object_path_startswith("/", "/"), ""));
+        assert_se(!object_path_startswith("/foo", "/bar"));
+        assert_se(!object_path_startswith("/", "/bar"));
+        assert_se(!object_path_startswith("/foo", ""));
+
+        assert_se(object_path_is_valid("/foo/bar"));
+        assert_se(object_path_is_valid("/foo"));
+        assert_se(object_path_is_valid("/"));
+        assert_se(object_path_is_valid("/foo5"));
+        assert_se(object_path_is_valid("/foo_5"));
+        assert_se(!object_path_is_valid(""));
+        assert_se(!object_path_is_valid("/foo/"));
+        assert_se(!object_path_is_valid("//"));
+        assert_se(!object_path_is_valid("//foo"));
+        assert_se(!object_path_is_valid("/foo//bar"));
+        assert_se(!object_path_is_valid("/foo/aaaäöä"));
+
+        OBJECT_PATH_FOREACH_PREFIX(prefix, "/") {
+                log_info("<%s>", prefix);
+                assert_not_reached("???");
+        }
+
+        r = 0;
+        OBJECT_PATH_FOREACH_PREFIX(prefix, "/xxx") {
+                log_info("<%s>", prefix);
+                assert_se(streq(prefix, "/"));
+                assert_se(r == 0);
+                r++;
+        }
+        assert_se(r == 1);
+
+        r = 0;
+        OBJECT_PATH_FOREACH_PREFIX(prefix, "/xxx/yyy/zzz") {
+                log_info("<%s>", prefix);
+                assert_se(r != 0 || streq(prefix, "/xxx/yyy"));
+                assert_se(r != 1 || streq(prefix, "/xxx"));
+                assert_se(r != 2 || streq(prefix, "/"));
+                r++;
+        }
+        assert_se(r == 3);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-track.c b/src/libsystemd/sd-bus/test-bus-track.c
new file mode 100644
index 0000000..64aa88b
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-track.c
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <sys/socket.h>
+
+#include "sd-bus.h"
+
+#include "macro.h"
+#include "tests.h"
+
+static bool track_cb_called_x = false;
+static bool track_cb_called_y = false;
+
+static int track_cb_x(sd_bus_track *t, void *userdata) {
+
+        log_error("TRACK CB X");
+
+        assert_se(!track_cb_called_x);
+        track_cb_called_x = true;
+
+        /* This means b's name disappeared. Let's now disconnect, to make sure the track handling on disconnect works
+         * as it should. */
+
+        assert_se(shutdown(sd_bus_get_fd(sd_bus_track_get_bus(t)), SHUT_RDWR) >= 0);
+        return 1;
+}
+
+static int track_cb_y(sd_bus_track *t, void *userdata) {
+        int r;
+
+        log_error("TRACK CB Y");
+
+        assert_se(!track_cb_called_y);
+        track_cb_called_y = true;
+
+        /* We got disconnected, let's close everything */
+
+        r = sd_event_exit(sd_bus_get_event(sd_bus_track_get_bus(t)), EXIT_SUCCESS);
+        assert_se(r >= 0);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+        _cleanup_(sd_bus_track_unrefp) sd_bus_track *x = NULL, *y = NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *a = NULL, *b = NULL;
+        bool use_system_bus = false;
+        const char *unique;
+        int r;
+
+        test_setup_logging(LOG_INFO);
+
+        r = sd_event_default(&event);
+        assert_se(r >= 0);
+
+        r = sd_bus_open_user(&a);
+        if (IN_SET(r, -ECONNREFUSED, -ENOENT, -ENOMEDIUM)) {
+                r = sd_bus_open_system(&a);
+                if (IN_SET(r, -ECONNREFUSED, -ENOENT))
+                        return log_tests_skipped("Failed to connect to bus");
+                use_system_bus = true;
+        }
+        assert_se(r >= 0);
+
+        r = sd_bus_attach_event(a, event, SD_EVENT_PRIORITY_NORMAL);
+        assert_se(r >= 0);
+
+        if (use_system_bus)
+                r = sd_bus_open_system(&b);
+        else
+                r = sd_bus_open_user(&b);
+        assert_se(r >= 0);
+
+        r = sd_bus_attach_event(b, event, SD_EVENT_PRIORITY_NORMAL);
+        assert_se(r >= 0);
+
+        /* Watch b's name from a */
+        r = sd_bus_track_new(a, &x, track_cb_x, NULL);
+        assert_se(r >= 0);
+
+        r = sd_bus_get_unique_name(b, &unique);
+        assert_se(r >= 0);
+
+        r = sd_bus_track_add_name(x, unique);
+        assert_se(r >= 0);
+
+        /* Watch's a's own name from a */
+        r = sd_bus_track_new(a, &y, track_cb_y, NULL);
+        assert_se(r >= 0);
+
+        r = sd_bus_get_unique_name(a, &unique);
+        assert_se(r >= 0);
+
+        r = sd_bus_track_add_name(y, unique);
+        assert_se(r >= 0);
+
+        /* Now make b's name disappear */
+        sd_bus_close(b);
+
+        r = sd_event_loop(event);
+        assert_se(r >= 0);
+
+        assert_se(track_cb_called_x);
+        assert_se(track_cb_called_y);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-vtable-cc.cc b/src/libsystemd/sd-bus/test-bus-vtable-cc.cc
new file mode 120000
index 0000000..abee398
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-vtable-cc.cc
@@ -0,0 +1 @@
+test-bus-vtable.c
\ No newline at end of file
diff --git a/src/libsystemd/sd-bus/test-bus-vtable.c b/src/libsystemd/sd-bus/test-bus-vtable.c
new file mode 100644
index 0000000..fe12238
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-vtable.c
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdbool.h>
+#include <stddef.h>
+
+/* We use system assert.h here, because we don't want to keep macro.h and log.h C++ compatible */
+#undef NDEBUG
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+
+#include "sd-bus-vtable.h"
+
+#ifndef __cplusplus
+#  include "bus-objects.h"
+#endif
+
+#include "test-vtable-data.h"
+
+#define DEFAULT_BUS_PATH "unix:path=/run/dbus/system_bus_socket"
+
+static struct context c = {};
+static int happy_finder_object = 0;
+
+static int happy_finder(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error) {
+        assert(userdata);
+        assert(userdata == &c);
+
+#ifndef __cplusplus
+        log_info("%s called", __func__);
+#endif
+
+        happy_finder_object++;
+        *found = &happy_finder_object;
+        return 1; /* found */
+}
+
+static void test_vtable(void) {
+        sd_bus *bus = NULL;
+        int r;
+
+        assert(sd_bus_new(&bus) >= 0);
+
+        assert(sd_bus_add_object_vtable(bus, NULL, "/foo", "org.freedesktop.systemd.testVtable", test_vtable_2, &c) >= 0);
+        assert(sd_bus_add_object_vtable(bus, NULL, "/foo", "org.freedesktop.systemd.testVtable2", test_vtable_2, &c) >= 0);
+        /* the cast on the line below is needed to test with the old version of the table */
+        assert(sd_bus_add_object_vtable(bus, NULL, "/foo", "org.freedesktop.systemd.testVtable221",
+                                        (const sd_bus_vtable *)vtable_format_221, &c) >= 0);
+
+        assert(sd_bus_add_fallback_vtable(bus, NULL, "/fallback", "org.freedesktop.systemd.testVtable2", test_vtable_2, happy_finder, &c) >= 0);
+
+        assert(sd_bus_set_address(bus, DEFAULT_BUS_PATH) >= 0);
+        r = sd_bus_start(bus);
+        assert(r == 0 ||     /* success */
+               r == -ENOENT  /* dbus is inactive */ );
+
+#ifndef __cplusplus
+        _cleanup_free_ char *s, *s2;
+
+        assert_se(introspect_path(bus, "/foo", NULL, false, true, NULL, &s, NULL) == 1);
+        fputs(s, stdout);
+
+        assert_se(introspect_path(bus, "/fallback", NULL, false, true, NULL, &s2, NULL) == 1);
+        fputs(s2, stdout);
+
+        assert_se(happy_finder_object == 1);
+#endif
+
+        sd_bus_unref(bus);
+}
+
+int main(int argc, char **argv) {
+        test_vtable();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-watch-bind.c b/src/libsystemd/sd-bus/test-bus-watch-bind.c
new file mode 100644
index 0000000..fdc8772
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-watch-bind.c
@@ -0,0 +1,224 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <pthread.h>
+
+#include "sd-bus.h"
+#include "sd-event.h"
+#include "sd-id128.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "mkdir.h"
+#include "path-util.h"
+#include "random-util.h"
+#include "rm-rf.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "tmpfile-util.h"
+#include "tests.h"
+
+static int method_foobar(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        log_info("Got Foobar() call.");
+
+        assert_se(sd_event_exit(sd_bus_get_event(sd_bus_message_get_bus(m)), 0) >= 0);
+        return sd_bus_reply_method_return(m, NULL);
+}
+
+static int method_exit(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        log_info("Got Exit() call");
+        assert_se(sd_event_exit(sd_bus_get_event(sd_bus_message_get_bus(m)), 1) >= 0);
+        return sd_bus_reply_method_return(m, NULL);
+}
+
+static const sd_bus_vtable vtable[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("Foobar", NULL, NULL, method_foobar, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("Exit", NULL, NULL, method_exit, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_VTABLE_END,
+};
+
+static void* thread_server(void *p) {
+        _cleanup_free_ char *suffixed = NULL, *suffixed2 = NULL, *d = NULL;
+        _cleanup_close_ int fd = -1;
+        union sockaddr_union u;
+        const char *path = p;
+        int r;
+
+        log_debug("Initializing server");
+
+        /* Let's play some games, by slowly creating the socket directory, and renaming it in the middle */
+        (void) usleep(100 * USEC_PER_MSEC);
+
+        assert_se(mkdir_parents(path, 0755) >= 0);
+        (void) usleep(100 * USEC_PER_MSEC);
+
+        d = dirname_malloc(path);
+        assert_se(d);
+        assert_se(asprintf(&suffixed, "%s.%" PRIx64, d, random_u64()) >= 0);
+        assert_se(rename(d, suffixed) >= 0);
+        (void) usleep(100 * USEC_PER_MSEC);
+
+        assert_se(asprintf(&suffixed2, "%s.%" PRIx64, d, random_u64()) >= 0);
+        assert_se(symlink(suffixed2, d) >= 0);
+        (void) usleep(100 * USEC_PER_MSEC);
+
+        assert_se(symlink(basename(suffixed), suffixed2) >= 0);
+        (void) usleep(100 * USEC_PER_MSEC);
+
+        socklen_t sa_len;
+        r = sockaddr_un_set_path(&u.un, path);
+        assert_se(r >= 0);
+        sa_len = r;
+
+        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+        assert_se(fd >= 0);
+
+        assert_se(bind(fd, &u.sa, sa_len) >= 0);
+        usleep(100 * USEC_PER_MSEC);
+
+        assert_se(listen(fd, SOMAXCONN) >= 0);
+        usleep(100 * USEC_PER_MSEC);
+
+        assert_se(touch(path) >= 0);
+        usleep(100 * USEC_PER_MSEC);
+
+        log_debug("Initialized server");
+
+        for (;;) {
+                _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+                _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+                sd_id128_t id;
+                int bus_fd, code;
+
+                assert_se(sd_id128_randomize(&id) >= 0);
+
+                assert_se(sd_event_new(&event) >= 0);
+
+                bus_fd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
+                assert_se(bus_fd >= 0);
+
+                log_debug("Accepted server connection");
+
+                assert_se(sd_bus_new(&bus) >= 0);
+                assert_se(sd_bus_set_description(bus, "server") >= 0);
+                assert_se(sd_bus_set_fd(bus, bus_fd, bus_fd) >= 0);
+                assert_se(sd_bus_set_server(bus, true, id) >= 0);
+                /* assert_se(sd_bus_set_anonymous(bus, true) >= 0); */
+
+                assert_se(sd_bus_attach_event(bus, event, 0) >= 0);
+
+                assert_se(sd_bus_add_object_vtable(bus, NULL, "/foo", "foo.TestInterface", vtable, NULL) >= 0);
+
+                assert_se(sd_bus_start(bus) >= 0);
+
+                assert_se(sd_event_loop(event) >= 0);
+
+                assert_se(sd_event_get_exit_code(event, &code) >= 0);
+
+                if (code > 0)
+                        break;
+        }
+
+        log_debug("Server done");
+
+        return NULL;
+}
+
+static void* thread_client1(void *p) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        const char *path = p, *t;
+        int r;
+
+        log_debug("Initializing client1");
+
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_description(bus, "client1") >= 0);
+
+        t = strjoina("unix:path=", path);
+        assert_se(sd_bus_set_address(bus, t) >= 0);
+        assert_se(sd_bus_set_watch_bind(bus, true) >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        r = sd_bus_call_method(bus, "foo.bar", "/foo", "foo.TestInterface", "Foobar", &error, NULL, NULL);
+        assert_se(r >= 0);
+
+        log_debug("Client1 done");
+
+        return NULL;
+}
+
+static int client2_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        assert_se(sd_bus_message_is_method_error(m, NULL) == 0);
+        assert_se(sd_event_exit(sd_bus_get_event(sd_bus_message_get_bus(m)), 0) >= 0);
+        return 0;
+}
+
+static void* thread_client2(void *p) {
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+        const char *path = p, *t;
+
+        log_debug("Initializing client2");
+
+        assert_se(sd_event_new(&event) >= 0);
+        assert_se(sd_bus_new(&bus) >= 0);
+        assert_se(sd_bus_set_description(bus, "client2") >= 0);
+
+        t = strjoina("unix:path=", path);
+        assert_se(sd_bus_set_address(bus, t) >= 0);
+        assert_se(sd_bus_set_watch_bind(bus, true) >= 0);
+        assert_se(sd_bus_attach_event(bus, event, 0) >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        assert_se(sd_bus_call_method_async(bus, NULL, "foo.bar", "/foo", "foo.TestInterface", "Foobar", client2_callback, NULL, NULL) >= 0);
+
+        assert_se(sd_event_loop(event) >= 0);
+
+        log_debug("Client2 done");
+
+        return NULL;
+}
+
+static void request_exit(const char *path) {
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        const char *t;
+
+        assert_se(sd_bus_new(&bus) >= 0);
+
+        t = strjoina("unix:path=", path);
+        assert_se(sd_bus_set_address(bus, t) >= 0);
+        assert_se(sd_bus_set_watch_bind(bus, true) >= 0);
+        assert_se(sd_bus_set_description(bus, "request-exit") >= 0);
+        assert_se(sd_bus_start(bus) >= 0);
+
+        assert_se(sd_bus_call_method(bus, "foo.bar", "/foo", "foo.TestInterface", "Exit", NULL, NULL, NULL) >= 0);
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(rm_rf_physical_and_freep) char *d = NULL;
+        pthread_t server, client1, client2;
+        char *path;
+
+        test_setup_logging(LOG_DEBUG);
+
+        /* We use /dev/shm here rather than /tmp, since some weird distros might set up /tmp as some weird fs that
+         * doesn't support inotify properly. */
+        assert_se(mkdtemp_malloc("/dev/shm/systemd-watch-bind-XXXXXX", &d) >= 0);
+
+        path = strjoina(d, "/this/is/a/socket");
+
+        assert_se(pthread_create(&server, NULL, thread_server, path) == 0);
+        assert_se(pthread_create(&client1, NULL, thread_client1, path) == 0);
+        assert_se(pthread_create(&client2, NULL, thread_client2, path) == 0);
+
+        assert_se(pthread_join(client1, NULL) == 0);
+        assert_se(pthread_join(client2, NULL) == 0);
+
+        request_exit(path);
+
+        assert_se(pthread_join(server, NULL) == 0);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-bus/test-vtable-data.h b/src/libsystemd/sd-bus/test-vtable-data.h
new file mode 100644
index 0000000..7269a49
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-vtable-data.h
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+/* This is meant to be included in other files, hence no headers */
+
+struct context {
+        bool quit;
+        char *something;
+        char *automatic_string_property;
+        uint32_t automatic_integer_property;
+};
+
+static int handler(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+        return 1;
+}
+
+static int value_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+        return 1;
+}
+
+static int get_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *reply, void *userdata, sd_bus_error *error) {
+        return 1;
+}
+
+static int set_handler(sd_bus *bus, const char *path, const char *interface, const char *property, sd_bus_message *value, void *userdata, sd_bus_error *error) {
+        return 1;
+}
+
+static const sd_bus_vtable test_vtable_1[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("Hello", "ssas", "a(uu)", NULL, 0),
+        SD_BUS_METHOD("DeprecatedHello", "", "", NULL, SD_BUS_VTABLE_DEPRECATED),
+        SD_BUS_METHOD("DeprecatedHelloNoReply", "", "", NULL, SD_BUS_VTABLE_DEPRECATED|SD_BUS_VTABLE_METHOD_NO_REPLY),
+        SD_BUS_SIGNAL("Wowza", "sss", 0),
+        SD_BUS_SIGNAL("DeprecatedWowza", "ut", SD_BUS_VTABLE_DEPRECATED),
+        SD_BUS_WRITABLE_PROPERTY("AProperty", "s", get_handler, set_handler, 0, 0),
+        SD_BUS_PROPERTY("AReadOnlyDeprecatedProperty", "(ut)", get_handler, 0, SD_BUS_VTABLE_DEPRECATED),
+        SD_BUS_PROPERTY("ChangingProperty", "t", get_handler, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+        SD_BUS_PROPERTY("Invalidating", "t", get_handler, 0, SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
+        SD_BUS_PROPERTY("Constant", "t", get_handler, 0, SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_PROPERTY_EXPLICIT),
+        SD_BUS_VTABLE_END
+};
+
+static const sd_bus_vtable test_vtable_2[] = {
+        SD_BUS_VTABLE_START(0),
+        SD_BUS_METHOD("AlterSomething", "s", "s", handler, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("Exit", "", "", handler, 0),
+        SD_BUS_METHOD_WITH_OFFSET("AlterSomething2", "s", "s", handler, 200, 0),
+        SD_BUS_METHOD_WITH_OFFSET("Exit2", "", "", handler, 200, 0),
+        SD_BUS_METHOD_WITH_NAMES_OFFSET("AlterSomething3", "so", SD_BUS_PARAM(string) SD_BUS_PARAM(path),
+                        "s", SD_BUS_PARAM(returnstring), handler, 200, 0),
+        SD_BUS_METHOD_WITH_NAMES("Exit3", "bx", SD_BUS_PARAM(with_confirmation) SD_BUS_PARAM(after_msec),
+                        "bb", SD_BUS_PARAM(accepted) SD_BUS_PARAM(scheduled), handler, 0),
+        SD_BUS_PROPERTY("Value", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+        SD_BUS_PROPERTY("Value2", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
+        SD_BUS_PROPERTY("Value3", "s", value_handler, 10, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("Value4", "s", value_handler, 10, 0),
+        SD_BUS_PROPERTY("AnExplicitProperty", "s", NULL, offsetof(struct context, something),
+                        SD_BUS_VTABLE_PROPERTY_EXPLICIT|SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
+        SD_BUS_WRITABLE_PROPERTY("Something", "s", get_handler, set_handler, 0, 0),
+        SD_BUS_WRITABLE_PROPERTY("AutomaticStringProperty", "s", NULL, NULL,
+                                 offsetof(struct context, automatic_string_property), 0),
+        SD_BUS_WRITABLE_PROPERTY("AutomaticIntegerProperty", "u", NULL, NULL,
+                                 offsetof(struct context, automatic_integer_property), 0),
+        SD_BUS_METHOD("NoOperation", NULL, NULL, NULL, 0),
+        SD_BUS_SIGNAL("DummySignal", "b", 0),
+        SD_BUS_SIGNAL("DummySignal2", "so", 0),
+        SD_BUS_SIGNAL_WITH_NAMES("DummySignal3", "so", SD_BUS_PARAM(string) SD_BUS_PARAM(path), 0),
+        SD_BUS_VTABLE_END
+};
+
+static const sd_bus_vtable test_vtable_deprecated[] = {
+        SD_BUS_VTABLE_START(SD_BUS_VTABLE_DEPRECATED),
+        SD_BUS_VTABLE_END
+};
+
+struct sd_bus_vtable_221 {
+        uint8_t type:8;
+        uint64_t flags:56;
+        union {
+                struct {
+                        size_t element_size;
+                } start;
+                struct {
+                        const char *member;
+                        const char *signature;
+                        const char *result;
+                        sd_bus_message_handler_t handler;
+                        size_t offset;
+                } method;
+                struct {
+                        const char *member;
+                        const char *signature;
+                } signal;
+                struct {
+                        const char *member;
+                        const char *signature;
+                        sd_bus_property_get_t get;
+                        sd_bus_property_set_t set;
+                        size_t offset;
+                } property;
+        } x;
+};
+
+static const struct sd_bus_vtable_221 vtable_format_221[] = {
+        {
+                .type = _SD_BUS_VTABLE_START,
+                .flags = 0,
+                .x = {
+                        .start = {
+                                .element_size = sizeof(struct sd_bus_vtable_221)
+                        },
+                },
+        },
+        {
+                .type = _SD_BUS_VTABLE_METHOD,
+                .flags = 0,
+                .x = {
+                        .method = {
+                                .member = "Exit",
+                                .signature = "",
+                                .result = "",
+                                .handler = handler,
+                                .offset = 0,
+                        },
+                },
+        },
+        {
+                .type = _SD_BUS_VTABLE_END,
+                .flags = 0,
+                .x = { { 0 } },
+        }
+};
diff --git a/src/libsystemd/sd-daemon/sd-daemon.c b/src/libsystemd/sd-daemon/sd-daemon.c
new file mode 100644
index 0000000..6f0b975
--- /dev/null
+++ b/src/libsystemd/sd-daemon/sd-daemon.c
@@ -0,0 +1,679 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <limits.h>
+#include <mqueue.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#include "sd-daemon.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "io-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "socket-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "util.h"
+
+#define SNDBUF_SIZE (8*1024*1024)
+
+static void unsetenv_all(bool unset_environment) {
+        if (!unset_environment)
+                return;
+
+        assert_se(unsetenv("LISTEN_PID") == 0);
+        assert_se(unsetenv("LISTEN_FDS") == 0);
+        assert_se(unsetenv("LISTEN_FDNAMES") == 0);
+}
+
+_public_ int sd_listen_fds(int unset_environment) {
+        const char *e;
+        int n, r, fd;
+        pid_t pid;
+
+        e = getenv("LISTEN_PID");
+        if (!e) {
+                r = 0;
+                goto finish;
+        }
+
+        r = parse_pid(e, &pid);
+        if (r < 0)
+                goto finish;
+
+        /* Is this for us? */
+        if (getpid_cached() != pid) {
+                r = 0;
+                goto finish;
+        }
+
+        e = getenv("LISTEN_FDS");
+        if (!e) {
+                r = 0;
+                goto finish;
+        }
+
+        r = safe_atoi(e, &n);
+        if (r < 0)
+                goto finish;
+
+        assert_cc(SD_LISTEN_FDS_START < INT_MAX);
+        if (n <= 0 || n > INT_MAX - SD_LISTEN_FDS_START) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++) {
+                r = fd_cloexec(fd, true);
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = n;
+
+finish:
+        unsetenv_all(unset_environment);
+        return r;
+}
+
+_public_ int sd_listen_fds_with_names(int unset_environment, char ***names) {
+        _cleanup_strv_free_ char **l = NULL;
+        bool have_names;
+        int n_names = 0, n_fds;
+        const char *e;
+        int r;
+
+        if (!names)
+                return sd_listen_fds(unset_environment);
+
+        e = getenv("LISTEN_FDNAMES");
+        if (e) {
+                n_names = strv_split_full(&l, e, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
+                if (n_names < 0) {
+                        unsetenv_all(unset_environment);
+                        return n_names;
+                }
+
+                have_names = true;
+        } else
+                have_names = false;
+
+        n_fds = sd_listen_fds(unset_environment);
+        if (n_fds <= 0)
+                return n_fds;
+
+        if (have_names) {
+                if (n_names != n_fds)
+                        return -EINVAL;
+        } else {
+                r = strv_extend_n(&l, "unknown", n_fds);
+                if (r < 0)
+                        return r;
+        }
+
+        *names = TAKE_PTR(l);
+
+        return n_fds;
+}
+
+_public_ int sd_is_fifo(int fd, const char *path) {
+        struct stat st_fd;
+
+        assert_return(fd >= 0, -EBADF);
+
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISFIFO(st_fd.st_mode))
+                return 0;
+
+        if (path) {
+                struct stat st_path;
+
+                if (stat(path, &st_path) < 0) {
+
+                        if (IN_SET(errno, ENOENT, ENOTDIR))
+                                return 0;
+
+                        return -errno;
+                }
+
+                return
+                        st_path.st_dev == st_fd.st_dev &&
+                        st_path.st_ino == st_fd.st_ino;
+        }
+
+        return 1;
+}
+
+_public_ int sd_is_special(int fd, const char *path) {
+        struct stat st_fd;
+
+        assert_return(fd >= 0, -EBADF);
+
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISREG(st_fd.st_mode) && !S_ISCHR(st_fd.st_mode))
+                return 0;
+
+        if (path) {
+                struct stat st_path;
+
+                if (stat(path, &st_path) < 0) {
+
+                        if (IN_SET(errno, ENOENT, ENOTDIR))
+                                return 0;
+
+                        return -errno;
+                }
+
+                if (S_ISREG(st_fd.st_mode) && S_ISREG(st_path.st_mode))
+                        return
+                                st_path.st_dev == st_fd.st_dev &&
+                                st_path.st_ino == st_fd.st_ino;
+                else if (S_ISCHR(st_fd.st_mode) && S_ISCHR(st_path.st_mode))
+                        return st_path.st_rdev == st_fd.st_rdev;
+                else
+                        return 0;
+        }
+
+        return 1;
+}
+
+static int sd_is_socket_internal(int fd, int type, int listening) {
+        struct stat st_fd;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(type >= 0, -EINVAL);
+
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISSOCK(st_fd.st_mode))
+                return 0;
+
+        if (type != 0) {
+                int other_type = 0;
+                socklen_t l = sizeof(other_type);
+
+                if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
+                        return -errno;
+
+                if (l != sizeof(other_type))
+                        return -EINVAL;
+
+                if (other_type != type)
+                        return 0;
+        }
+
+        if (listening >= 0) {
+                int accepting = 0;
+                socklen_t l = sizeof(accepting);
+
+                if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
+                        return -errno;
+
+                if (l != sizeof(accepting))
+                        return -EINVAL;
+
+                if (!accepting != !listening)
+                        return 0;
+        }
+
+        return 1;
+}
+
+_public_ int sd_is_socket(int fd, int family, int type, int listening) {
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(family >= 0, -EINVAL);
+
+        r = sd_is_socket_internal(fd, type, listening);
+        if (r <= 0)
+                return r;
+
+        if (family > 0) {
+                union sockaddr_union sockaddr = {};
+                socklen_t l = sizeof(sockaddr);
+
+                if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                        return -errno;
+
+                if (l < sizeof(sa_family_t))
+                        return -EINVAL;
+
+                return sockaddr.sa.sa_family == family;
+        }
+
+        return 1;
+}
+
+_public_ int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
+        union sockaddr_union sockaddr = {};
+        socklen_t l = sizeof(sockaddr);
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(IN_SET(family, 0, AF_INET, AF_INET6), -EINVAL);
+
+        r = sd_is_socket_internal(fd, type, listening);
+        if (r <= 0)
+                return r;
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (!IN_SET(sockaddr.sa.sa_family, AF_INET, AF_INET6))
+                return 0;
+
+        if (family != 0)
+                if (sockaddr.sa.sa_family != family)
+                        return 0;
+
+        if (port > 0) {
+                unsigned sa_port;
+
+                r = sockaddr_port(&sockaddr.sa, &sa_port);
+                if (r < 0)
+                        return r;
+
+                return port == sa_port;
+        }
+
+        return 1;
+}
+
+_public_ int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening) {
+        union sockaddr_union sockaddr = {};
+        socklen_t l = sizeof(sockaddr);
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(addr, -EINVAL);
+        assert_return(addr_len >= sizeof(sa_family_t), -ENOBUFS);
+        assert_return(IN_SET(addr->sa_family, AF_INET, AF_INET6), -EPFNOSUPPORT);
+
+        r = sd_is_socket_internal(fd, type, listening);
+        if (r <= 0)
+                return r;
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (sockaddr.sa.sa_family != addr->sa_family)
+                return 0;
+
+        if (sockaddr.sa.sa_family == AF_INET) {
+                const struct sockaddr_in *in = (const struct sockaddr_in *) addr;
+
+                if (l < sizeof(struct sockaddr_in) || addr_len < sizeof(struct sockaddr_in))
+                        return -EINVAL;
+
+                if (in->sin_port != 0 &&
+                    sockaddr.in.sin_port != in->sin_port)
+                        return false;
+
+                return sockaddr.in.sin_addr.s_addr == in->sin_addr.s_addr;
+
+        } else {
+                const struct sockaddr_in6 *in = (const struct sockaddr_in6 *) addr;
+
+                if (l < sizeof(struct sockaddr_in6) || addr_len < sizeof(struct sockaddr_in6))
+                        return -EINVAL;
+
+                if (in->sin6_port != 0 &&
+                    sockaddr.in6.sin6_port != in->sin6_port)
+                        return false;
+
+                if (in->sin6_flowinfo != 0 &&
+                    sockaddr.in6.sin6_flowinfo != in->sin6_flowinfo)
+                        return false;
+
+                if (in->sin6_scope_id != 0 &&
+                    sockaddr.in6.sin6_scope_id != in->sin6_scope_id)
+                        return false;
+
+                return memcmp(sockaddr.in6.sin6_addr.s6_addr, in->sin6_addr.s6_addr,
+                              sizeof(in->sin6_addr.s6_addr)) == 0;
+        }
+}
+
+_public_ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
+        union sockaddr_union sockaddr = {};
+        socklen_t l = sizeof(sockaddr);
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+
+        r = sd_is_socket_internal(fd, type, listening);
+        if (r <= 0)
+                return r;
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (sockaddr.sa.sa_family != AF_UNIX)
+                return 0;
+
+        if (path) {
+                if (length == 0)
+                        length = strlen(path);
+
+                if (length == 0)
+                        /* Unnamed socket */
+                        return l == offsetof(struct sockaddr_un, sun_path);
+
+                if (path[0])
+                        /* Normal path socket */
+                        return
+                                (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
+                                memcmp(path, sockaddr.un.sun_path, length+1) == 0;
+                else
+                        /* Abstract namespace socket */
+                        return
+                                (l == offsetof(struct sockaddr_un, sun_path) + length) &&
+                                memcmp(path, sockaddr.un.sun_path, length) == 0;
+        }
+
+        return 1;
+}
+
+_public_ int sd_is_mq(int fd, const char *path) {
+        struct mq_attr attr;
+
+        /* Check that the fd is valid */
+        assert_return(fcntl(fd, F_GETFD) >= 0, -errno);
+
+        if (mq_getattr(fd, &attr) < 0) {
+                if (errno == EBADF)
+                        /* A non-mq fd (or an invalid one, but we ruled that out above) */
+                        return 0;
+                return -errno;
+        }
+
+        if (path) {
+                char fpath[PATH_MAX];
+                struct stat a, b;
+
+                assert_return(path_is_absolute(path), -EINVAL);
+
+                if (fstat(fd, &a) < 0)
+                        return -errno;
+
+                strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
+                fpath[sizeof(fpath)-1] = 0;
+
+                if (stat(fpath, &b) < 0)
+                        return -errno;
+
+                if (a.st_dev != b.st_dev ||
+                    a.st_ino != b.st_ino)
+                        return 0;
+        }
+
+        return 1;
+}
+
+_public_ int sd_pid_notify_with_fds(
+                pid_t pid,
+                int unset_environment,
+                const char *state,
+                const int *fds,
+                unsigned n_fds) {
+
+        union sockaddr_union sockaddr;
+        struct iovec iovec;
+        struct msghdr msghdr = {
+                .msg_iov = &iovec,
+                .msg_iovlen = 1,
+                .msg_name = &sockaddr,
+        };
+        _cleanup_close_ int fd = -1;
+        struct cmsghdr *cmsg = NULL;
+        const char *e;
+        bool send_ucred;
+        int r;
+
+        if (!state) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        if (n_fds > 0 && !fds) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        e = getenv("NOTIFY_SOCKET");
+        if (!e)
+                return 0;
+
+        r = sockaddr_un_set_path(&sockaddr.un, e);
+        if (r < 0)
+                goto finish;
+        msghdr.msg_namelen = r;
+
+        fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+        if (fd < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        (void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
+
+        iovec = IOVEC_MAKE_STRING(state);
+
+        send_ucred =
+                (pid != 0 && pid != getpid_cached()) ||
+                getuid() != geteuid() ||
+                getgid() != getegid();
+
+        if (n_fds > 0 || send_ucred) {
+                /* CMSG_SPACE(0) may return value different than zero, which results in miscalculated controllen. */
+                msghdr.msg_controllen =
+                        (n_fds > 0 ? CMSG_SPACE(sizeof(int) * n_fds) : 0) +
+                        (send_ucred ? CMSG_SPACE(sizeof(struct ucred)) : 0);
+
+                msghdr.msg_control = alloca0(msghdr.msg_controllen);
+
+                cmsg = CMSG_FIRSTHDR(&msghdr);
+                if (n_fds > 0) {
+                        cmsg->cmsg_level = SOL_SOCKET;
+                        cmsg->cmsg_type = SCM_RIGHTS;
+                        cmsg->cmsg_len = CMSG_LEN(sizeof(int) * n_fds);
+
+                        memcpy(CMSG_DATA(cmsg), fds, sizeof(int) * n_fds);
+
+                        if (send_ucred)
+                                assert_se(cmsg = CMSG_NXTHDR(&msghdr, cmsg));
+                }
+
+                if (send_ucred) {
+                        struct ucred *ucred;
+
+                        cmsg->cmsg_level = SOL_SOCKET;
+                        cmsg->cmsg_type = SCM_CREDENTIALS;
+                        cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
+
+                        ucred = (struct ucred*) CMSG_DATA(cmsg);
+                        ucred->pid = pid != 0 ? pid : getpid_cached();
+                        ucred->uid = getuid();
+                        ucred->gid = getgid();
+                }
+        }
+
+        /* First try with fake ucred data, as requested */
+        if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
+                r = 1;
+                goto finish;
+        }
+
+        /* If that failed, try with our own ucred instead */
+        if (send_ucred) {
+                msghdr.msg_controllen -= CMSG_SPACE(sizeof(struct ucred));
+                if (msghdr.msg_controllen == 0)
+                        msghdr.msg_control = NULL;
+
+                if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) >= 0) {
+                        r = 1;
+                        goto finish;
+                }
+        }
+
+        r = -errno;
+
+finish:
+        if (unset_environment)
+                assert_se(unsetenv("NOTIFY_SOCKET") == 0);
+
+        return r;
+}
+
+_public_ int sd_notify_barrier(int unset_environment, uint64_t timeout) {
+        _cleanup_close_pair_ int pipe_fd[2] = { -1, -1 };
+        int r;
+
+        if (pipe2(pipe_fd, O_CLOEXEC) < 0)
+                return -errno;
+
+        r = sd_pid_notify_with_fds(0, unset_environment, "BARRIER=1", &pipe_fd[1], 1);
+        if (r <= 0)
+                return r;
+
+        pipe_fd[1] = safe_close(pipe_fd[1]);
+
+        r = fd_wait_for_event(pipe_fd[0], 0 /* POLLHUP is implicit */, timeout);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ETIMEDOUT;
+
+        return 1;
+}
+
+_public_ int sd_pid_notify(pid_t pid, int unset_environment, const char *state) {
+        return sd_pid_notify_with_fds(pid, unset_environment, state, NULL, 0);
+}
+
+_public_ int sd_notify(int unset_environment, const char *state) {
+        return sd_pid_notify_with_fds(0, unset_environment, state, NULL, 0);
+}
+
+_public_ int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        if (format) {
+                va_list ap;
+
+                va_start(ap, format);
+                r = vasprintf(&p, format, ap);
+                va_end(ap);
+
+                if (r < 0 || !p)
+                        return -ENOMEM;
+        }
+
+        return sd_pid_notify(pid, unset_environment, p);
+}
+
+_public_ int sd_notifyf(int unset_environment, const char *format, ...) {
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        if (format) {
+                va_list ap;
+
+                va_start(ap, format);
+                r = vasprintf(&p, format, ap);
+                va_end(ap);
+
+                if (r < 0 || !p)
+                        return -ENOMEM;
+        }
+
+        return sd_pid_notify(0, unset_environment, p);
+}
+
+_public_ int sd_booted(void) {
+        /* We test whether the runtime unit file directory has been
+         * created. This takes place in mount-setup.c, so is
+         * guaranteed to happen very early during boot. */
+
+        if (laccess("/run/systemd/system/", F_OK) >= 0)
+                return true;
+
+        if (errno == ENOENT)
+                return false;
+
+        return -errno;
+}
+
+_public_ int sd_watchdog_enabled(int unset_environment, uint64_t *usec) {
+        const char *s, *p = ""; /* p is set to dummy value to do unsetting */
+        uint64_t u;
+        int r = 0;
+
+        s = getenv("WATCHDOG_USEC");
+        if (!s)
+                goto finish;
+
+        r = safe_atou64(s, &u);
+        if (r < 0)
+                goto finish;
+        if (u <= 0 || u >= USEC_INFINITY) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        p = getenv("WATCHDOG_PID");
+        if (p) {
+                pid_t pid;
+
+                r = parse_pid(p, &pid);
+                if (r < 0)
+                        goto finish;
+
+                /* Is this for us? */
+                if (getpid_cached() != pid) {
+                        r = 0;
+                        goto finish;
+                }
+        }
+
+        if (usec)
+                *usec = u;
+
+        r = 1;
+
+finish:
+        if (unset_environment && s)
+                assert_se(unsetenv("WATCHDOG_USEC") == 0);
+        if (unset_environment && p)
+                assert_se(unsetenv("WATCHDOG_PID") == 0);
+
+        return r;
+}
diff --git a/src/libsystemd/sd-device/device-enumerator-private.h b/src/libsystemd/sd-device/device-enumerator-private.h
new file mode 100644
index 0000000..9c6437d
--- /dev/null
+++ b/src/libsystemd/sd-device/device-enumerator-private.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-device.h"
+
+int device_enumerator_scan_devices(sd_device_enumerator *enumeartor);
+int device_enumerator_scan_subsystems(sd_device_enumerator *enumeartor);
+int device_enumerator_add_device(sd_device_enumerator *enumerator, sd_device *device);
+int device_enumerator_add_match_is_initialized(sd_device_enumerator *enumerator);
+int device_enumerator_add_match_parent_incremental(sd_device_enumerator *enumerator, sd_device *parent);
+sd_device *device_enumerator_get_first(sd_device_enumerator *enumerator);
+sd_device *device_enumerator_get_next(sd_device_enumerator *enumerator);
+sd_device **device_enumerator_get_devices(sd_device_enumerator *enumerator, size_t *ret_n_devices);
+
+#define FOREACH_DEVICE_AND_SUBSYSTEM(enumerator, device)       \
+        for (device = device_enumerator_get_first(enumerator); \
+             device;                                           \
+             device = device_enumerator_get_next(enumerator))
diff --git a/src/libsystemd/sd-device/device-enumerator.c b/src/libsystemd/sd-device/device-enumerator.c
new file mode 100644
index 0000000..3641348
--- /dev/null
+++ b/src/libsystemd/sd-device/device-enumerator.c
@@ -0,0 +1,963 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-enumerator-private.h"
+#include "device-util.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "set.h"
+#include "sort-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+#define DEVICE_ENUMERATE_MAX_DEPTH 256
+
+typedef enum DeviceEnumerationType {
+        DEVICE_ENUMERATION_TYPE_DEVICES,
+        DEVICE_ENUMERATION_TYPE_SUBSYSTEMS,
+        _DEVICE_ENUMERATION_TYPE_MAX,
+        _DEVICE_ENUMERATION_TYPE_INVALID = -1,
+} DeviceEnumerationType;
+
+struct sd_device_enumerator {
+        unsigned n_ref;
+
+        DeviceEnumerationType type;
+        sd_device **devices;
+        size_t n_devices, n_allocated, current_device_index;
+        bool scan_uptodate;
+
+        Set *match_subsystem;
+        Set *nomatch_subsystem;
+        Hashmap *match_sysattr;
+        Hashmap *nomatch_sysattr;
+        Hashmap *match_property;
+        Set *match_sysname;
+        Set *match_tag;
+        Set *match_parent;
+        bool match_allow_uninitialized;
+};
+
+_public_ int sd_device_enumerator_new(sd_device_enumerator **ret) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *enumerator = NULL;
+
+        assert(ret);
+
+        enumerator = new(sd_device_enumerator, 1);
+        if (!enumerator)
+                return -ENOMEM;
+
+        *enumerator = (sd_device_enumerator) {
+                .n_ref = 1,
+                .type = _DEVICE_ENUMERATION_TYPE_INVALID,
+        };
+
+        *ret = TAKE_PTR(enumerator);
+
+        return 0;
+}
+
+static sd_device_enumerator *device_enumerator_free(sd_device_enumerator *enumerator) {
+        size_t i;
+
+        assert(enumerator);
+
+        for (i = 0; i < enumerator->n_devices; i++)
+                sd_device_unref(enumerator->devices[i]);
+
+        free(enumerator->devices);
+        set_free(enumerator->match_subsystem);
+        set_free(enumerator->nomatch_subsystem);
+        hashmap_free(enumerator->match_sysattr);
+        hashmap_free(enumerator->nomatch_sysattr);
+        hashmap_free(enumerator->match_property);
+        set_free(enumerator->match_sysname);
+        set_free(enumerator->match_tag);
+        set_free(enumerator->match_parent);
+
+        return mfree(enumerator);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device_enumerator, sd_device_enumerator, device_enumerator_free);
+
+_public_ int sd_device_enumerator_add_match_subsystem(sd_device_enumerator *enumerator, const char *subsystem, int match) {
+        Set **set;
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+
+        if (match)
+                set = &enumerator->match_subsystem;
+        else
+                set = &enumerator->nomatch_subsystem;
+
+        r = set_put_strdup(set, subsystem);
+        if (r <= 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+_public_ int sd_device_enumerator_add_match_sysattr(sd_device_enumerator *enumerator, const char *sysattr, const char *value, int match) {
+        Hashmap **hashmap;
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(sysattr, -EINVAL);
+
+        if (match)
+                hashmap = &enumerator->match_sysattr;
+        else
+                hashmap = &enumerator->nomatch_sysattr;
+
+        r = hashmap_put_strdup_full(hashmap, &trivial_hash_ops_free_free, sysattr, value);
+        if (r <= 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+_public_ int sd_device_enumerator_add_match_property(sd_device_enumerator *enumerator, const char *property, const char *value) {
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(property, -EINVAL);
+
+        r = hashmap_put_strdup_full(&enumerator->match_property, &trivial_hash_ops_free_free, property, value);
+        if (r <= 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+_public_ int sd_device_enumerator_add_match_sysname(sd_device_enumerator *enumerator, const char *sysname) {
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(sysname, -EINVAL);
+
+        r = set_put_strdup(&enumerator->match_sysname, sysname);
+        if (r <= 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+_public_ int sd_device_enumerator_add_match_tag(sd_device_enumerator *enumerator, const char *tag) {
+        int r;
+
+        assert_return(enumerator, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        r = set_put_strdup(&enumerator->match_tag, tag);
+        if (r <= 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+int device_enumerator_add_match_parent_incremental(sd_device_enumerator *enumerator, sd_device *parent) {
+        const char *path;
+        int r;
+
+        assert(enumerator);
+        assert(parent);
+
+        r = sd_device_get_syspath(parent, &path);
+        if (r < 0)
+                return r;
+
+        r = set_put_strdup(&enumerator->match_parent, path);
+        if (r <= 0)
+                return r;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+_public_ int sd_device_enumerator_add_match_parent(sd_device_enumerator *enumerator, sd_device *parent) {
+        assert_return(enumerator, -EINVAL);
+        assert_return(parent, -EINVAL);
+
+        set_clear(enumerator->match_parent);
+
+        return device_enumerator_add_match_parent_incremental(enumerator, parent);
+}
+
+_public_ int sd_device_enumerator_allow_uninitialized(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, -EINVAL);
+
+        enumerator->match_allow_uninitialized = true;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+int device_enumerator_add_match_is_initialized(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, -EINVAL);
+
+        enumerator->match_allow_uninitialized = false;
+
+        enumerator->scan_uptodate = false;
+
+        return 1;
+}
+
+static int device_compare(sd_device * const *_a, sd_device * const *_b) {
+        sd_device *a = *(sd_device **)_a, *b = *(sd_device **)_b;
+        const char *devpath_a, *devpath_b, *sound_a;
+        bool delay_a, delay_b;
+        int r;
+
+        assert_se(sd_device_get_devpath(a, &devpath_a) >= 0);
+        assert_se(sd_device_get_devpath(b, &devpath_b) >= 0);
+
+        sound_a = strstr(devpath_a, "/sound/card");
+        if (sound_a) {
+                /* For sound cards the control device must be enumerated last to
+                 * make sure it's the final device node that gets ACLs applied.
+                 * Applications rely on this fact and use ACL changes on the
+                 * control node as an indicator that the ACL change of the
+                 * entire sound card completed. The kernel makes this guarantee
+                 * when creating those devices, and hence we should too when
+                 * enumerating them. */
+                sound_a += STRLEN("/sound/card");
+                sound_a = strchr(sound_a, '/');
+
+                if (sound_a) {
+                        unsigned prefix_len;
+
+                        prefix_len = sound_a - devpath_a;
+
+                        if (strncmp(devpath_a, devpath_b, prefix_len) == 0) {
+                                const char *sound_b;
+
+                                sound_b = devpath_b + prefix_len;
+
+                                if (startswith(sound_a, "/controlC") &&
+                                    !startswith(sound_b, "/contolC"))
+                                        return 1;
+
+                                if (!startswith(sound_a, "/controlC") &&
+                                    startswith(sound_b, "/controlC"))
+                                        return -1;
+                        }
+                }
+        }
+
+        /* md and dm devices are enumerated after all other devices */
+        delay_a = strstr(devpath_a, "/block/md") || strstr(devpath_a, "/block/dm-");
+        delay_b = strstr(devpath_b, "/block/md") || strstr(devpath_b, "/block/dm-");
+        r = CMP(delay_a, delay_b);
+        if (r != 0)
+                return r;
+
+        return strcmp(devpath_a, devpath_b);
+}
+
+int device_enumerator_add_device(sd_device_enumerator *enumerator, sd_device *device) {
+        assert_return(enumerator, -EINVAL);
+        assert_return(device, -EINVAL);
+
+        if (!GREEDY_REALLOC(enumerator->devices, enumerator->n_allocated, enumerator->n_devices + 1))
+                return -ENOMEM;
+
+        enumerator->devices[enumerator->n_devices++] = sd_device_ref(device);
+
+        return 0;
+}
+
+static bool match_sysattr_value(sd_device *device, const char *sysattr, const char *match_value) {
+        const char *value;
+        int r;
+
+        assert(device);
+        assert(sysattr);
+
+        r = sd_device_get_sysattr_value(device, sysattr, &value);
+        if (r < 0)
+                return false;
+
+        if (!match_value)
+                return true;
+
+        if (fnmatch(match_value, value, 0) == 0)
+                return true;
+
+        return false;
+}
+
+static bool match_sysattr(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *sysattr;
+        const char *value;
+
+        assert(enumerator);
+        assert(device);
+
+        HASHMAP_FOREACH_KEY(value, sysattr, enumerator->nomatch_sysattr)
+                if (match_sysattr_value(device, sysattr, value))
+                        return false;
+
+        HASHMAP_FOREACH_KEY(value, sysattr, enumerator->match_sysattr)
+                if (!match_sysattr_value(device, sysattr, value))
+                        return false;
+
+        return true;
+}
+
+static bool match_property(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *property;
+        const char *value;
+
+        assert(enumerator);
+        assert(device);
+
+        if (hashmap_isempty(enumerator->match_property))
+                return true;
+
+        HASHMAP_FOREACH_KEY(value, property, enumerator->match_property) {
+                const char *property_dev, *value_dev;
+
+                FOREACH_DEVICE_PROPERTY(device, property_dev, value_dev) {
+                        if (fnmatch(property, property_dev, 0) != 0)
+                                continue;
+
+                        if (!value && !value_dev)
+                                return true;
+
+                        if (!value || !value_dev)
+                                continue;
+
+                        if (fnmatch(value, value_dev, 0) == 0)
+                                return true;
+                }
+        }
+
+        return false;
+}
+
+static bool match_tag(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *tag;
+
+        assert(enumerator);
+        assert(device);
+
+        SET_FOREACH(tag, enumerator->match_tag)
+                if (!sd_device_has_tag(device, tag))
+                        return false;
+
+        return true;
+}
+
+static bool match_parent(sd_device_enumerator *enumerator, sd_device *device) {
+        const char *syspath_parent, *syspath;
+
+        assert(enumerator);
+        assert(device);
+
+        if (set_isempty(enumerator->match_parent))
+                return true;
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+
+        SET_FOREACH(syspath_parent, enumerator->match_parent)
+                if (path_startswith(syspath, syspath_parent))
+                        return true;
+
+        return false;
+}
+
+static bool match_sysname(sd_device_enumerator *enumerator, const char *sysname) {
+        const char *sysname_match;
+
+        assert(enumerator);
+        assert(sysname);
+
+        if (set_isempty(enumerator->match_sysname))
+                return true;
+
+        SET_FOREACH(sysname_match, enumerator->match_sysname)
+                if (fnmatch(sysname_match, sysname, 0) == 0)
+                        return true;
+
+        return false;
+}
+
+static int enumerator_scan_dir_and_add_devices(sd_device_enumerator *enumerator, const char *basedir, const char *subdir1, const char *subdir2) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *path;
+        struct dirent *dent;
+        int r = 0;
+
+        assert(enumerator);
+        assert(basedir);
+
+        path = strjoina("/sys/", basedir, "/");
+
+        if (subdir1)
+                path = strjoina(path, subdir1, "/");
+
+        if (subdir2)
+                path = strjoina(path, subdir2, "/");
+
+        dir = opendir(path);
+        if (!dir)
+                /* this is necessarily racey, so ignore missing directories */
+                return (errno == ENOENT && (subdir1 || subdir2)) ? 0 : -errno;
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+                char syspath[strlen(path) + 1 + strlen(dent->d_name) + 1];
+                int initialized, k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                if (!match_sysname(enumerator, dent->d_name))
+                        continue;
+
+                (void) sprintf(syspath, "%s%s", path, dent->d_name);
+
+                k = sd_device_new_from_syspath(&device, syspath);
+                if (k < 0) {
+                        if (k != -ENODEV)
+                                /* this is necessarily racey, so ignore missing devices */
+                                r = k;
+
+                        continue;
+                }
+
+                initialized = sd_device_get_is_initialized(device);
+                if (initialized < 0) {
+                        if (initialized != -ENOENT)
+                                /* this is necessarily racey, so ignore missing devices */
+                                r = initialized;
+
+                        continue;
+                }
+
+                /*
+                 * All devices with a device node or network interfaces
+                 * possibly need udev to adjust the device node permission
+                 * or context, or rename the interface before it can be
+                 * reliably used from other processes.
+                 *
+                 * For now, we can only check these types of devices, we
+                 * might not store a database, and have no way to find out
+                 * for all other types of devices.
+                 */
+                if (!enumerator->match_allow_uninitialized &&
+                    !initialized &&
+                    (sd_device_get_devnum(device, NULL) >= 0 ||
+                     sd_device_get_ifindex(device, NULL) >= 0))
+                        continue;
+
+                if (!match_parent(enumerator, device))
+                        continue;
+
+                if (!match_tag(enumerator, device))
+                        continue;
+
+                if (!match_property(enumerator, device))
+                        continue;
+
+                if (!match_sysattr(enumerator, device))
+                        continue;
+
+                k = device_enumerator_add_device(enumerator, device);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static bool match_subsystem(sd_device_enumerator *enumerator, const char *subsystem) {
+        const char *subsystem_match;
+
+        assert(enumerator);
+
+        if (!subsystem)
+                return false;
+
+        SET_FOREACH(subsystem_match, enumerator->nomatch_subsystem)
+                if (fnmatch(subsystem_match, subsystem, 0) == 0)
+                        return false;
+
+        if (set_isempty(enumerator->match_subsystem))
+                return true;
+
+        SET_FOREACH(subsystem_match, enumerator->match_subsystem)
+                if (fnmatch(subsystem_match, subsystem, 0) == 0)
+                        return true;
+
+        return false;
+}
+
+static int enumerator_scan_dir(sd_device_enumerator *enumerator, const char *basedir, const char *subdir, const char *subsystem) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *path;
+        struct dirent *dent;
+        int r = 0;
+
+        path = strjoina("/sys/", basedir);
+
+        dir = opendir(path);
+        if (!dir)
+                return -errno;
+
+        log_debug("sd-device-enumerator: Scanning %s", path);
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                int k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                if (!match_subsystem(enumerator, subsystem ? : dent->d_name))
+                        continue;
+
+                k = enumerator_scan_dir_and_add_devices(enumerator, basedir, dent->d_name, subdir);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_tag(sd_device_enumerator *enumerator, const char *tag) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        char *path;
+        struct dirent *dent;
+        int r = 0;
+
+        assert(enumerator);
+        assert(tag);
+
+        path = strjoina("/run/udev/tags/", tag);
+
+        dir = opendir(path);
+        if (!dir) {
+                if (errno != ENOENT)
+                        return log_debug_errno(errno, "sd-device-enumerator: Failed to open tags directory %s: %m", path);
+                return 0;
+        }
+
+        /* TODO: filter away subsystems? */
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+                const char *subsystem, *sysname;
+                int k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                k = sd_device_new_from_device_id(&device, dent->d_name);
+                if (k < 0) {
+                        if (k != -ENODEV)
+                                /* this is necessarily racy, so ignore missing devices */
+                                r = k;
+
+                        continue;
+                }
+
+                k = sd_device_get_subsystem(device, &subsystem);
+                if (k < 0) {
+                        if (k != -ENOENT)
+                                /* this is necessarily racy, so ignore missing devices */
+                                r = k;
+                        continue;
+                }
+
+                if (!match_subsystem(enumerator, subsystem))
+                        continue;
+
+                k = sd_device_get_sysname(device, &sysname);
+                if (k < 0) {
+                        r = k;
+                        continue;
+                }
+
+                if (!match_sysname(enumerator, sysname))
+                        continue;
+
+                if (!match_parent(enumerator, device))
+                        continue;
+
+                if (!match_property(enumerator, device))
+                        continue;
+
+                if (!match_sysattr(enumerator, device))
+                        continue;
+
+                k = device_enumerator_add_device(enumerator, device);
+                if (k < 0) {
+                        r = k;
+                        continue;
+                }
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_tags(sd_device_enumerator *enumerator) {
+        const char *tag;
+        int r = 0;
+
+        assert(enumerator);
+
+        SET_FOREACH(tag, enumerator->match_tag) {
+                int k;
+
+                k = enumerator_scan_devices_tag(enumerator, tag);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int parent_add_child(sd_device_enumerator *enumerator, const char *path) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        const char *subsystem, *sysname;
+        int r;
+
+        r = sd_device_new_from_syspath(&device, path);
+        if (r == -ENODEV)
+                /* this is necessarily racy, so ignore missing devices */
+                return 0;
+        else if (r < 0)
+                return r;
+
+        r = sd_device_get_subsystem(device, &subsystem);
+        if (r == -ENOENT)
+                return 0;
+        if (r < 0)
+                return r;
+
+        if (!match_subsystem(enumerator, subsystem))
+                return 0;
+
+        r = sd_device_get_sysname(device, &sysname);
+        if (r < 0)
+                return r;
+
+        if (!match_sysname(enumerator, sysname))
+                return 0;
+
+        if (!match_property(enumerator, device))
+                return 0;
+
+        if (!match_sysattr(enumerator, device))
+                return 0;
+
+        r = device_enumerator_add_device(enumerator, device);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int parent_crawl_children(sd_device_enumerator *enumerator, const char *path, unsigned maxdepth) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        struct dirent *dent;
+        int r = 0;
+
+        dir = opendir(path);
+        if (!dir)
+                return log_debug_errno(errno, "sd-device-enumerator: Failed to open parent directory %s: %m", path);
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_free_ char *child = NULL;
+                int k;
+
+                if (dent->d_name[0] == '.')
+                        continue;
+
+                if (dent->d_type != DT_DIR)
+                        continue;
+
+                child = path_join(path, dent->d_name);
+                if (!child)
+                        return -ENOMEM;
+
+                k = parent_add_child(enumerator, child);
+                if (k < 0)
+                        r = k;
+
+                if (maxdepth > 0)
+                        parent_crawl_children(enumerator, child, maxdepth - 1);
+                else
+                        log_debug("sd-device-enumerator: Max depth reached, %s: ignoring devices", child);
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_children(sd_device_enumerator *enumerator) {
+        const char *path;
+        int r = 0, k;
+
+        SET_FOREACH(path, enumerator->match_parent) {
+                k = parent_add_child(enumerator, path);
+                if (k < 0)
+                        r = k;
+
+                k = parent_crawl_children(enumerator, path, DEVICE_ENUMERATE_MAX_DEPTH);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int enumerator_scan_devices_all(sd_device_enumerator *enumerator) {
+        int r = 0;
+
+        log_debug("sd-device-enumerator: Scan all dirs");
+
+        if (access("/sys/subsystem", F_OK) >= 0) {
+                /* we have /subsystem/, forget all the old stuff */
+                r = enumerator_scan_dir(enumerator, "subsystem", "devices", NULL);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-enumerator: Failed to scan /sys/subsystem: %m");
+        } else {
+                int k;
+
+                k = enumerator_scan_dir(enumerator, "bus", "devices", NULL);
+                if (k < 0)
+                        r = log_debug_errno(k, "sd-device-enumerator: Failed to scan /sys/bus: %m");
+
+                k = enumerator_scan_dir(enumerator, "class", NULL, NULL);
+                if (k < 0)
+                        r = log_debug_errno(k, "sd-device-enumerator: Failed to scan /sys/class: %m");
+        }
+
+        return r;
+}
+
+static void device_enumerator_dedup_devices(sd_device_enumerator *enumerator) {
+        sd_device **a, **b, **end;
+
+        assert(enumerator);
+
+        if (enumerator->n_devices <= 1)
+                return;
+
+        a = enumerator->devices + 1;
+        b = enumerator->devices;
+        end = enumerator->devices + enumerator->n_devices;
+
+        for (; a < end; a++) {
+                const char *devpath_a, *devpath_b;
+
+                assert_se(sd_device_get_devpath(*a, &devpath_a) >= 0);
+                assert_se(sd_device_get_devpath(*b, &devpath_b) >= 0);
+
+                if (path_equal(devpath_a, devpath_b))
+                        sd_device_unref(*a);
+                else
+                        *(++b) = *a;
+        }
+
+        enumerator->n_devices = b - enumerator->devices + 1;
+}
+
+int device_enumerator_scan_devices(sd_device_enumerator *enumerator) {
+        int r = 0, k;
+        size_t i;
+
+        assert(enumerator);
+
+        if (enumerator->scan_uptodate &&
+            enumerator->type == DEVICE_ENUMERATION_TYPE_DEVICES)
+                return 0;
+
+        for (i = 0; i < enumerator->n_devices; i++)
+                sd_device_unref(enumerator->devices[i]);
+
+        enumerator->n_devices = 0;
+
+        if (!set_isempty(enumerator->match_tag)) {
+                k = enumerator_scan_devices_tags(enumerator);
+                if (k < 0)
+                        r = k;
+        } else if (enumerator->match_parent) {
+                k = enumerator_scan_devices_children(enumerator);
+                if (k < 0)
+                        r = k;
+        } else {
+                k = enumerator_scan_devices_all(enumerator);
+                if (k < 0)
+                        r = k;
+        }
+
+        typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
+        device_enumerator_dedup_devices(enumerator);
+
+        enumerator->scan_uptodate = true;
+        enumerator->type = DEVICE_ENUMERATION_TYPE_DEVICES;
+
+        return r;
+}
+
+_public_ sd_device *sd_device_enumerator_get_device_first(sd_device_enumerator *enumerator) {
+        int r;
+
+        assert_return(enumerator, NULL);
+
+        r = device_enumerator_scan_devices(enumerator);
+        if (r < 0)
+                return NULL;
+
+        enumerator->current_device_index = 0;
+
+        if (enumerator->n_devices == 0)
+                return NULL;
+
+        return enumerator->devices[0];
+}
+
+_public_ sd_device *sd_device_enumerator_get_device_next(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate ||
+            enumerator->type != DEVICE_ENUMERATION_TYPE_DEVICES ||
+            enumerator->current_device_index + 1 >= enumerator->n_devices)
+                return NULL;
+
+        return enumerator->devices[++enumerator->current_device_index];
+}
+
+int device_enumerator_scan_subsystems(sd_device_enumerator *enumerator) {
+        const char *subsysdir;
+        int r = 0, k;
+        size_t i;
+
+        assert(enumerator);
+
+        if (enumerator->scan_uptodate &&
+            enumerator->type == DEVICE_ENUMERATION_TYPE_SUBSYSTEMS)
+                return 0;
+
+        for (i = 0; i < enumerator->n_devices; i++)
+                sd_device_unref(enumerator->devices[i]);
+
+        enumerator->n_devices = 0;
+
+        /* modules */
+        if (match_subsystem(enumerator, "module")) {
+                k = enumerator_scan_dir_and_add_devices(enumerator, "module", NULL, NULL);
+                if (k < 0)
+                        r = log_debug_errno(k, "sd-device-enumerator: Failed to scan modules: %m");
+        }
+
+        if (access("/sys/subsystem", F_OK) >= 0)
+                subsysdir = "subsystem";
+        else
+                subsysdir = "bus";
+
+        /* subsystems (only buses support coldplug) */
+        if (match_subsystem(enumerator, "subsystem")) {
+                k = enumerator_scan_dir_and_add_devices(enumerator, subsysdir, NULL, NULL);
+                if (k < 0)
+                        r = log_debug_errno(k, "sd-device-enumerator: Failed to scan subsystems: %m");
+        }
+
+        /* subsystem drivers */
+        if (match_subsystem(enumerator, "drivers")) {
+                k = enumerator_scan_dir(enumerator, subsysdir, "drivers", "drivers");
+                if (k < 0)
+                        r = log_debug_errno(k, "sd-device-enumerator: Failed to scan drivers: %m");
+        }
+
+        typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
+        device_enumerator_dedup_devices(enumerator);
+
+        enumerator->scan_uptodate = true;
+        enumerator->type = DEVICE_ENUMERATION_TYPE_SUBSYSTEMS;
+
+        return r;
+}
+
+_public_ sd_device *sd_device_enumerator_get_subsystem_first(sd_device_enumerator *enumerator) {
+        int r;
+
+        assert_return(enumerator, NULL);
+
+        r = device_enumerator_scan_subsystems(enumerator);
+        if (r < 0)
+                return NULL;
+
+        enumerator->current_device_index = 0;
+
+        if (enumerator->n_devices == 0)
+                return NULL;
+
+        return enumerator->devices[0];
+}
+
+_public_ sd_device *sd_device_enumerator_get_subsystem_next(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate ||
+            enumerator->type != DEVICE_ENUMERATION_TYPE_SUBSYSTEMS ||
+            enumerator->current_device_index + 1 >= enumerator->n_devices)
+                return NULL;
+
+        return enumerator->devices[++enumerator->current_device_index];
+}
+
+sd_device *device_enumerator_get_first(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate)
+                return NULL;
+
+        enumerator->current_device_index = 0;
+
+        if (enumerator->n_devices == 0)
+                return NULL;
+
+        return enumerator->devices[0];
+}
+
+sd_device *device_enumerator_get_next(sd_device_enumerator *enumerator) {
+        assert_return(enumerator, NULL);
+
+        if (!enumerator->scan_uptodate ||
+            enumerator->current_device_index + 1 >= enumerator->n_devices)
+                return NULL;
+
+        return enumerator->devices[++enumerator->current_device_index];
+}
+
+sd_device **device_enumerator_get_devices(sd_device_enumerator *enumerator, size_t *ret_n_devices) {
+        assert(enumerator);
+        assert(ret_n_devices);
+
+        if (!enumerator->scan_uptodate)
+                return NULL;
+
+        *ret_n_devices = enumerator->n_devices;
+        return enumerator->devices;
+}
diff --git a/src/libsystemd/sd-device/device-internal.h b/src/libsystemd/sd-device/device-internal.h
new file mode 100644
index 0000000..3321c8e
--- /dev/null
+++ b/src/libsystemd/sd-device/device-internal.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-device.h"
+
+#include "device-private.h"
+#include "hashmap.h"
+#include "set.h"
+#include "time-util.h"
+
+#define LATEST_UDEV_DATABASE_VERSION 1
+
+struct sd_device {
+        unsigned n_ref;
+
+        /* The database version indicates the supported features by the udev database.
+         * This is saved and parsed in V field.
+         *
+         * 0: None of the following features are supported (systemd version <= 246).
+         * 1: The current tags (Q) and the database version (V) features are implemented (>= 247).
+         */
+        unsigned database_version;
+
+        int watch_handle;
+
+        sd_device *parent;
+
+        OrderedHashmap *properties;
+        Iterator properties_iterator;
+        uint64_t properties_generation; /* changes whenever the properties are changed */
+        uint64_t properties_iterator_generation; /* generation when iteration was started */
+
+        /* the subset of the properties that should be written to the db */
+        OrderedHashmap *properties_db;
+
+        Hashmap *sysattr_values; /* cached sysattr values */
+
+        Set *sysattrs; /* names of sysattrs */
+        Iterator sysattrs_iterator;
+
+        Set *all_tags, *current_tags;
+        Iterator all_tags_iterator, current_tags_iterator;
+        uint64_t all_tags_iterator_generation, current_tags_iterator_generation; /* generation when iteration was started */
+        uint64_t tags_generation; /* changes whenever the tags are changed */
+
+        Set *devlinks;
+        Iterator devlinks_iterator;
+        uint64_t devlinks_generation; /* changes whenever the devlinks are changed */
+        uint64_t devlinks_iterator_generation; /* generation when iteration was started */
+        int devlink_priority;
+
+        int ifindex;
+        char *devtype;
+        char *devname;
+        dev_t devnum;
+
+        char **properties_strv; /* the properties hashmap as a strv */
+        uint8_t *properties_nulstr; /* the same as a nulstr */
+        size_t properties_nulstr_len;
+
+        char *syspath;
+        const char *devpath;
+        const char *sysnum;
+        char *sysname;
+
+        char *subsystem;
+        char *driver_subsystem; /* only set for the 'drivers' subsystem */
+        char *driver;
+
+        char *id_filename;
+
+        uint64_t usec_initialized;
+
+        mode_t devmode;
+        uid_t devuid;
+        gid_t devgid;
+
+        /* only set when device is passed through netlink */
+        DeviceAction action;
+        uint64_t seqnum;
+
+        bool parent_set:1; /* no need to try to reload parent */
+        bool sysattrs_read:1; /* don't try to re-read sysattrs once read */
+        bool property_tags_outdated:1; /* need to update TAGS= or CURRENT_TAGS= property */
+        bool property_devlinks_outdated:1; /* need to update DEVLINKS= property */
+        bool properties_buf_outdated:1; /* need to reread hashmap */
+        bool sysname_set:1; /* don't reread sysname */
+        bool subsystem_set:1; /* don't reread subsystem */
+        bool driver_subsystem_set:1; /* don't reread subsystem */
+        bool driver_set:1; /* don't reread driver */
+        bool uevent_loaded:1; /* don't reread uevent */
+        bool db_loaded; /* don't reread db */
+
+        bool is_initialized:1;
+        bool sealed:1; /* don't read more information from uevent/db */
+        bool db_persist:1; /* don't clean up the db when switching from initrd to real root */
+};
+
+int device_new_aux(sd_device **ret);
+int device_add_property_aux(sd_device *device, const char *key, const char *value, bool db);
+static inline int device_add_property_internal(sd_device *device, const char *key, const char *value) {
+        return device_add_property_aux(device, key, value, false);
+}
+int device_read_uevent_file(sd_device *device);
+
+int device_set_syspath(sd_device *device, const char *_syspath, bool verify);
+int device_set_ifindex(sd_device *device, const char *ifindex);
+int device_set_devmode(sd_device *device, const char *devmode);
+int device_set_devname(sd_device *device, const char *devname);
+int device_set_devtype(sd_device *device, const char *devtype);
+int device_set_devnum(sd_device *device, const char *major, const char *minor);
+int device_set_subsystem(sd_device *device, const char *_subsystem);
+int device_set_driver(sd_device *device, const char *_driver);
+int device_set_usec_initialized(sd_device *device, usec_t when);
diff --git a/src/libsystemd/sd-device/device-monitor-private.h b/src/libsystemd/sd-device/device-monitor-private.h
new file mode 100644
index 0000000..2ca3a31
--- /dev/null
+++ b/src/libsystemd/sd-device/device-monitor-private.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-device.h"
+
+typedef enum MonitorNetlinkGroup {
+        MONITOR_GROUP_NONE,
+        MONITOR_GROUP_KERNEL,
+        MONITOR_GROUP_UDEV,
+        _MONITOR_NETLINK_GROUP_MAX,
+        _MONITOR_NETLINK_GROUP_INVALID = -1,
+} MonitorNetlinkGroup;
+
+int device_monitor_new_full(sd_device_monitor **ret, MonitorNetlinkGroup group, int fd);
+int device_monitor_disconnect(sd_device_monitor *m);
+int device_monitor_allow_unicast_sender(sd_device_monitor *m, sd_device_monitor *sender);
+int device_monitor_enable_receiving(sd_device_monitor *m);
+int device_monitor_get_fd(sd_device_monitor *m);
+int device_monitor_send_device(sd_device_monitor *m, sd_device_monitor *destination, sd_device *device);
+int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret);
diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
new file mode 100644
index 0000000..fd59007
--- /dev/null
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -0,0 +1,772 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <linux/filter.h>
+#include <linux/netlink.h>
+#include <linux/sockios.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "sd-device.h"
+#include "sd-event.h"
+
+#include "MurmurHash2.h"
+#include "alloc-util.h"
+#include "device-monitor-private.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "hashmap.h"
+#include "io-util.h"
+#include "missing_socket.h"
+#include "mountpoint-util.h"
+#include "set.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+struct sd_device_monitor {
+        unsigned n_ref;
+
+        int sock;
+        union sockaddr_union snl;
+        union sockaddr_union snl_trusted_sender;
+        bool bound;
+
+        Hashmap *subsystem_filter;
+        Set *tag_filter;
+        bool filter_uptodate;
+
+        sd_event *event;
+        sd_event_source *event_source;
+        sd_device_monitor_handler_t callback;
+        void *userdata;
+};
+
+#define UDEV_MONITOR_MAGIC                0xfeedcafe
+
+typedef struct monitor_netlink_header {
+        /* "libudev" prefix to distinguish libudev and kernel messages */
+        char prefix[8];
+        /* Magic to protect against daemon <-> Library message format mismatch
+         * Used in the kernel from socket filter rules; needs to be stored in network order */
+        unsigned magic;
+        /* Total length of header structure known to the sender */
+        unsigned header_size;
+        /* Properties string buffer */
+        unsigned properties_off;
+        unsigned properties_len;
+        /* Hashes of primary device properties strings, to let libudev subscribers
+         * use in-kernel socket filters; values need to be stored in network order */
+        unsigned filter_subsystem_hash;
+        unsigned filter_devtype_hash;
+        unsigned filter_tag_bloom_hi;
+        unsigned filter_tag_bloom_lo;
+} monitor_netlink_header;
+
+static int monitor_set_nl_address(sd_device_monitor *m) {
+        union sockaddr_union snl;
+        socklen_t addrlen;
+
+        assert(m);
+
+        /* Get the address the kernel has assigned us.
+         * It is usually, but not necessarily the pid. */
+        addrlen = sizeof(struct sockaddr_nl);
+        if (getsockname(m->sock, &snl.sa, &addrlen) < 0)
+                return -errno;
+
+        m->snl.nl.nl_pid = snl.nl.nl_pid;
+        return 0;
+}
+
+int device_monitor_allow_unicast_sender(sd_device_monitor *m, sd_device_monitor *sender) {
+        assert_return(m, -EINVAL);
+        assert_return(sender, -EINVAL);
+
+        m->snl_trusted_sender.nl.nl_pid = sender->snl.nl.nl_pid;
+        return 0;
+}
+
+_public_ int sd_device_monitor_set_receive_buffer_size(sd_device_monitor *m, size_t size) {
+        assert_return(m, -EINVAL);
+
+        return fd_set_rcvbuf(m->sock, size, false);
+}
+
+int device_monitor_disconnect(sd_device_monitor *m) {
+        assert(m);
+
+        m->sock = safe_close(m->sock);
+        return 0;
+}
+
+int device_monitor_get_fd(sd_device_monitor *m) {
+        assert_return(m, -EINVAL);
+
+        return m->sock;
+}
+
+int device_monitor_new_full(sd_device_monitor **ret, MonitorNetlinkGroup group, int fd) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *m = NULL;
+        _cleanup_close_ int sock = -1;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(group >= 0 && group < _MONITOR_NETLINK_GROUP_MAX, -EINVAL);
+
+        if (group == MONITOR_GROUP_UDEV &&
+            access("/run/udev/control", F_OK) < 0 &&
+            dev_is_devtmpfs() <= 0) {
+
+                /*
+                 * We do not support subscribing to uevents if no instance of
+                 * udev is running. Uevents would otherwise broadcast the
+                 * processing data of the host into containers, which is not
+                 * desired.
+                 *
+                 * Containers will currently not get any udev uevents, until
+                 * a supporting infrastructure is available.
+                 *
+                 * We do not set a netlink multicast group here, so the socket
+                 * will not receive any messages.
+                 */
+
+                log_debug("sd-device-monitor: The udev service seems not to be active, disabling the monitor");
+                group = MONITOR_GROUP_NONE;
+        }
+
+        if (fd < 0) {
+                sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
+                if (sock < 0)
+                        return log_debug_errno(errno, "sd-device-monitor: Failed to create socket: %m");
+        }
+
+        m = new(sd_device_monitor, 1);
+        if (!m)
+                return -ENOMEM;
+
+        *m = (sd_device_monitor) {
+                .n_ref = 1,
+                .sock = fd >= 0 ? fd : TAKE_FD(sock),
+                .bound = fd >= 0,
+                .snl.nl.nl_family = AF_NETLINK,
+                .snl.nl.nl_groups = group,
+        };
+
+        if (fd >= 0) {
+                r = monitor_set_nl_address(m);
+                if (r < 0) {
+                        log_debug_errno(r, "sd-device-monitor: Failed to set netlink address: %m");
+                        goto fail;
+                }
+        }
+
+        if (DEBUG_LOGGING) {
+                _cleanup_close_ int netns = -1;
+
+                /* So here's the thing: only AF_NETLINK sockets from the main network namespace will get
+                 * hardware events. Let's check if ours is from there, and if not generate a debug message,
+                 * since we cannot possibly work correctly otherwise. This is just a safety check to make
+                 * things easier to debug. */
+
+                netns = ioctl(m->sock, SIOCGSKNS);
+                if (netns < 0)
+                        log_debug_errno(errno, "sd-device-monitor: Unable to get network namespace of udev netlink socket, unable to determine if we are in host netns: %m");
+                else {
+                        struct stat a, b;
+
+                        if (fstat(netns, &a) < 0) {
+                                r = log_debug_errno(errno, "sd-device-monitor: Failed to stat netns of udev netlink socket: %m");
+                                goto fail;
+                        }
+
+                        if (stat("/proc/1/ns/net", &b) < 0) {
+                                if (ERRNO_IS_PRIVILEGE(errno))
+                                        /* If we can't access PID1's netns info due to permissions, it's fine, this is a
+                                         * safety check only after all. */
+                                        log_debug_errno(errno, "sd-device-monitor: No permission to stat PID1's netns, unable to determine if we are in host netns: %m");
+                                else
+                                        log_debug_errno(errno, "sd-device-monitor: Failed to stat PID1's netns: %m");
+
+                        } else if (a.st_dev != b.st_dev || a.st_ino != b.st_ino)
+                                log_debug("sd-device-monitor: Netlink socket we listen on is not from host netns, we won't see device events.");
+                }
+        }
+
+        *ret = TAKE_PTR(m);
+        return 0;
+
+fail:
+        /* Let's unset the socket fd in the monitor object before we destroy it so that the fd passed in is
+         * not closed on failure. */
+        if (fd >= 0)
+                m->sock = -1;
+
+        return r;
+}
+
+_public_ int sd_device_monitor_new(sd_device_monitor **ret) {
+        return device_monitor_new_full(ret, MONITOR_GROUP_UDEV, -1);
+}
+
+_public_ int sd_device_monitor_stop(sd_device_monitor *m) {
+        assert_return(m, -EINVAL);
+
+        m->event_source = sd_event_source_unref(m->event_source);
+        (void) device_monitor_disconnect(m);
+
+        return 0;
+}
+
+static int device_monitor_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        sd_device_monitor *m = userdata;
+
+        assert(m);
+
+        if (device_monitor_receive_device(m, &device) <= 0)
+                return 0;
+
+        if (m->callback)
+                return m->callback(m, device, m->userdata);
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_start(sd_device_monitor *m, sd_device_monitor_handler_t callback, void *userdata) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        if (!m->event) {
+                r = sd_device_monitor_attach_event(m, NULL);
+                if (r < 0)
+                        return r;
+        }
+
+        r = device_monitor_enable_receiving(m);
+        if (r < 0)
+                return r;
+
+        m->callback = callback;
+        m->userdata = userdata;
+
+        r = sd_event_add_io(m->event, &m->event_source, m->sock, EPOLLIN, device_monitor_event_handler, m);
+        if (r < 0)
+                return r;
+
+        (void) sd_event_source_set_description(m->event_source, "sd-device-monitor");
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_detach_event(sd_device_monitor *m) {
+        assert_return(m, -EINVAL);
+
+        (void) sd_device_monitor_stop(m);
+        m->event = sd_event_unref(m->event);
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_attach_event(sd_device_monitor *m, sd_event *event) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->event, -EBUSY);
+
+        if (event)
+                m->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&m->event);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+_public_ sd_event *sd_device_monitor_get_event(sd_device_monitor *m) {
+        assert_return(m, NULL);
+
+        return m->event;
+}
+
+_public_ sd_event_source *sd_device_monitor_get_event_source(sd_device_monitor *m) {
+        assert_return(m, NULL);
+
+        return m->event_source;
+}
+
+int device_monitor_enable_receiving(sd_device_monitor *m) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = sd_device_monitor_filter_update(m);
+        if (r < 0)
+                return log_debug_errno(r, "sd-device-monitor: Failed to update filter: %m");
+
+        if (!m->bound) {
+                /* enable receiving of sender credentials */
+                r = setsockopt_int(m->sock, SOL_SOCKET, SO_PASSCRED, true);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-monitor: Failed to set socket option SO_PASSCRED: %m");
+
+                if (bind(m->sock, &m->snl.sa, sizeof(struct sockaddr_nl)) < 0)
+                        return log_debug_errno(errno, "sd-device-monitor: Failed to bind monitoring socket: %m");
+
+                m->bound = true;
+
+                r = monitor_set_nl_address(m);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device-monitor: Failed to set address: %m");
+        }
+
+        return 0;
+}
+
+static sd_device_monitor *device_monitor_free(sd_device_monitor *m) {
+        assert(m);
+
+        (void) sd_device_monitor_detach_event(m);
+
+        hashmap_free_free_free(m->subsystem_filter);
+        set_free_free(m->tag_filter);
+
+        return mfree(m);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device_monitor, sd_device_monitor, device_monitor_free);
+
+static int passes_filter(sd_device_monitor *m, sd_device *device) {
+        const char *tag, *subsystem, *devtype, *s, *d = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(device, -EINVAL);
+
+        if (hashmap_isempty(m->subsystem_filter))
+                goto tag;
+
+        r = sd_device_get_subsystem(device, &s);
+        if (r < 0)
+                return r;
+
+        r = sd_device_get_devtype(device, &d);
+        if (r < 0 && r != -ENOENT)
+                return r;
+
+        HASHMAP_FOREACH_KEY(devtype, subsystem, m->subsystem_filter) {
+                if (!streq(s, subsystem))
+                        continue;
+
+                if (!devtype)
+                        goto tag;
+
+                if (!d)
+                        continue;
+
+                if (streq(d, devtype))
+                        goto tag;
+        }
+
+        return 0;
+
+tag:
+        if (set_isempty(m->tag_filter))
+                return 1;
+
+        SET_FOREACH(tag, m->tag_filter)
+                if (sd_device_has_tag(device, tag) > 0)
+                        return 1;
+
+        return 0;
+}
+
+int device_monitor_receive_device(sd_device_monitor *m, sd_device **ret) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        union {
+                monitor_netlink_header nlh;
+                char raw[8192];
+        } buf;
+        struct iovec iov = {
+                .iov_base = &buf,
+                .iov_len = sizeof(buf)
+        };
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
+        union sockaddr_union snl;
+        struct msghdr smsg = {
+                .msg_iov = &iov,
+                .msg_iovlen = 1,
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+                .msg_name = &snl,
+                .msg_namelen = sizeof(snl),
+        };
+        struct cmsghdr *cmsg;
+        struct ucred *cred;
+        ssize_t buflen, bufpos;
+        bool is_initialized = false;
+        int r;
+
+        assert(ret);
+
+        buflen = recvmsg(m->sock, &smsg, 0);
+        if (buflen < 0) {
+                if (errno != EINTR)
+                        log_debug_errno(errno, "sd-device-monitor: Failed to receive message: %m");
+                return -errno;
+        }
+
+        if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "sd-device-monitor: Invalid message length.");
+
+        if (snl.nl.nl_groups == MONITOR_GROUP_NONE) {
+                /* unicast message, check if we trust the sender */
+                if (m->snl_trusted_sender.nl.nl_pid == 0 ||
+                    snl.nl.nl_pid != m->snl_trusted_sender.nl.nl_pid)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Unicast netlink message ignored.");
+
+        } else if (snl.nl.nl_groups == MONITOR_GROUP_KERNEL) {
+                if (snl.nl.nl_pid > 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Multicast kernel netlink message from PID %"PRIu32" ignored.", snl.nl.nl_pid);
+        }
+
+        cmsg = CMSG_FIRSTHDR(&smsg);
+        if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS)
+                return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                       "sd-device-monitor: No sender credentials received, message ignored.");
+
+        cred = (struct ucred*) CMSG_DATA(cmsg);
+        if (cred->uid != 0)
+                return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                       "sd-device-monitor: Sender uid="UID_FMT", message ignored.", cred->uid);
+
+        if (streq(buf.raw, "libudev")) {
+                /* udev message needs proper version magic */
+                if (buf.nlh.magic != htobe32(UDEV_MONITOR_MAGIC))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message signature (%x != %x)",
+                                               buf.nlh.magic, htobe32(UDEV_MONITOR_MAGIC));
+
+                if (buf.nlh.properties_off+32 > (size_t) buflen)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message length (%u > %zd)",
+                                               buf.nlh.properties_off+32, buflen);
+
+                bufpos = buf.nlh.properties_off;
+
+                /* devices received from udev are always initialized */
+                is_initialized = true;
+
+        } else {
+                /* kernel message with header */
+                bufpos = strlen(buf.raw) + 1;
+                if ((size_t) bufpos < sizeof("a@/d") || bufpos >= buflen)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message length");
+
+                /* check message header */
+                if (!strstr(buf.raw, "@/"))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EAGAIN),
+                                               "sd-device-monitor: Invalid message header");
+        }
+
+        r = device_new_from_nulstr(&device, (uint8_t*) &buf.raw[bufpos], buflen - bufpos);
+        if (r < 0)
+                return log_debug_errno(r, "sd-device-monitor: Failed to create device from received message: %m");
+
+        if (is_initialized)
+                device_set_is_initialized(device);
+
+        /* Skip device, if it does not pass the current filter */
+        r = passes_filter(m, device);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device-monitor: Failed to check received device passing filter: %m");
+        if (r == 0)
+                log_device_debug(device, "sd-device-monitor: Received device does not pass filter, ignoring");
+        else
+                *ret = TAKE_PTR(device);
+
+        return r;
+}
+
+static uint32_t string_hash32(const char *str) {
+        return MurmurHash2(str, strlen(str), 0);
+}
+
+/* Get a bunch of bit numbers out of the hash, and set the bits in our bit field */
+static uint64_t string_bloom64(const char *str) {
+        uint64_t bits = 0;
+        uint32_t hash = string_hash32(str);
+
+        bits |= 1LLU << (hash & 63);
+        bits |= 1LLU << ((hash >> 6) & 63);
+        bits |= 1LLU << ((hash >> 12) & 63);
+        bits |= 1LLU << ((hash >> 18) & 63);
+        return bits;
+}
+
+int device_monitor_send_device(
+                sd_device_monitor *m,
+                sd_device_monitor *destination,
+                sd_device *device) {
+
+        monitor_netlink_header nlh = {
+                .prefix = "libudev",
+                .magic = htobe32(UDEV_MONITOR_MAGIC),
+                .header_size = sizeof nlh,
+        };
+        struct iovec iov[2] = {
+                { .iov_base = &nlh, .iov_len = sizeof nlh },
+        };
+        struct msghdr smsg = {
+                .msg_iov = iov,
+                .msg_iovlen = 2,
+        };
+        /* default destination for sending */
+        union sockaddr_union default_destination = {
+                .nl.nl_family = AF_NETLINK,
+                .nl.nl_groups = MONITOR_GROUP_UDEV,
+        };
+        uint64_t tag_bloom_bits;
+        const char *buf, *val;
+        ssize_t count;
+        size_t blen;
+        int r;
+
+        assert(m);
+        assert(device);
+
+        r = device_get_properties_nulstr(device, (const uint8_t **) &buf, &blen);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device-monitor: Failed to get device properties: %m");
+        if (blen < 32)
+                log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL),
+                                       "sd-device-monitor: Length of device property nulstr is too small to contain valid device information");
+
+        /* fill in versioned header */
+        r = sd_device_get_subsystem(device, &val);
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device-monitor: Failed to get device subsystem: %m");
+        nlh.filter_subsystem_hash = htobe32(string_hash32(val));
+
+        if (sd_device_get_devtype(device, &val) >= 0)
+                nlh.filter_devtype_hash = htobe32(string_hash32(val));
+
+        /* add tag bloom filter */
+        tag_bloom_bits = 0;
+        FOREACH_DEVICE_TAG(device, val)
+                tag_bloom_bits |= string_bloom64(val);
+
+        if (tag_bloom_bits > 0) {
+                nlh.filter_tag_bloom_hi = htobe32(tag_bloom_bits >> 32);
+                nlh.filter_tag_bloom_lo = htobe32(tag_bloom_bits & 0xffffffff);
+        }
+
+        /* add properties list */
+        nlh.properties_off = iov[0].iov_len;
+        nlh.properties_len = blen;
+        iov[1] = IOVEC_MAKE((char*) buf, blen);
+
+        /*
+         * Use custom address for target, or the default one.
+         *
+         * If we send to a multicast group, we will get
+         * ECONNREFUSED, which is expected.
+         */
+        smsg.msg_name = destination ? &destination->snl : &default_destination;
+        smsg.msg_namelen = sizeof(struct sockaddr_nl);
+        count = sendmsg(m->sock, &smsg, 0);
+        if (count < 0) {
+                if (!destination && errno == ECONNREFUSED) {
+                        log_device_debug(device, "sd-device-monitor: Passed to netlink monitor");
+                        return 0;
+                } else
+                        return log_device_debug_errno(device, errno, "sd-device-monitor: Failed to send device to netlink monitor: %m");
+        }
+
+        log_device_debug(device, "sd-device-monitor: Passed %zi byte to netlink monitor", count);
+        return count;
+}
+
+static void bpf_stmt(struct sock_filter *ins, unsigned *i,
+                     unsigned short code, unsigned data) {
+        ins[(*i)++] = (struct sock_filter) {
+                .code = code,
+                .k = data,
+        };
+}
+
+static void bpf_jmp(struct sock_filter *ins, unsigned *i,
+                    unsigned short code, unsigned data,
+                    unsigned short jt, unsigned short jf) {
+        ins[(*i)++] = (struct sock_filter) {
+                .code = code,
+                .jt = jt,
+                .jf = jf,
+                .k = data,
+        };
+}
+
+_public_ int sd_device_monitor_filter_update(sd_device_monitor *m) {
+        struct sock_filter ins[512] = {};
+        struct sock_fprog filter;
+        const char *subsystem, *devtype, *tag;
+        unsigned i = 0;
+
+        assert_return(m, -EINVAL);
+
+        if (m->filter_uptodate)
+                return 0;
+
+        if (hashmap_isempty(m->subsystem_filter) &&
+            set_isempty(m->tag_filter)) {
+                m->filter_uptodate = true;
+                return 0;
+        }
+
+        /* load magic in A */
+        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, magic));
+        /* jump if magic matches */
+        bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, UDEV_MONITOR_MAGIC, 1, 0);
+        /* wrong magic, pass packet */
+        bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+        if (!set_isempty(m->tag_filter)) {
+                int tag_matches = set_size(m->tag_filter);
+
+                /* add all tags matches */
+                SET_FOREACH(tag, m->tag_filter) {
+                        uint64_t tag_bloom_bits = string_bloom64(tag);
+                        uint32_t tag_bloom_hi = tag_bloom_bits >> 32;
+                        uint32_t tag_bloom_lo = tag_bloom_bits & 0xffffffff;
+
+                        /* load device bloom bits in A */
+                        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_tag_bloom_hi));
+                        /* clear bits (tag bits & bloom bits) */
+                        bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_hi);
+                        /* jump to next tag if it does not match */
+                        bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_hi, 0, 3);
+
+                        /* load device bloom bits in A */
+                        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_tag_bloom_lo));
+                        /* clear bits (tag bits & bloom bits) */
+                        bpf_stmt(ins, &i, BPF_ALU|BPF_AND|BPF_K, tag_bloom_lo);
+                        /* jump behind end of tag match block if tag matches */
+                        tag_matches--;
+                        bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, tag_bloom_lo, 1 + (tag_matches * 6), 0);
+                }
+
+                /* nothing matched, drop packet */
+                bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
+        }
+
+        /* add all subsystem matches */
+        if (!hashmap_isempty(m->subsystem_filter)) {
+                HASHMAP_FOREACH_KEY(devtype, subsystem, m->subsystem_filter) {
+                        uint32_t hash = string_hash32(subsystem);
+
+                        /* load device subsystem value in A */
+                        bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_subsystem_hash));
+                        if (!devtype) {
+                                /* jump if subsystem does not match */
+                                bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
+                        } else {
+                                /* jump if subsystem does not match */
+                                bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 3);
+                                /* load device devtype value in A */
+                                bpf_stmt(ins, &i, BPF_LD|BPF_W|BPF_ABS, offsetof(monitor_netlink_header, filter_devtype_hash));
+                                /* jump if value does not match */
+                                hash = string_hash32(devtype);
+                                bpf_jmp(ins, &i, BPF_JMP|BPF_JEQ|BPF_K, hash, 0, 1);
+                        }
+
+                        /* matched, pass packet */
+                        bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+                        if (i+1 >= ELEMENTSOF(ins))
+                                return -E2BIG;
+                }
+
+                /* nothing matched, drop packet */
+                bpf_stmt(ins, &i, BPF_RET|BPF_K, 0);
+        }
+
+        /* matched, pass packet */
+        bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
+
+        /* install filter */
+        filter = (struct sock_fprog) {
+                .len = i,
+                .filter = ins,
+        };
+        if (setsockopt(m->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) < 0)
+                return -errno;
+
+        m->filter_uptodate = true;
+        return 0;
+}
+
+_public_ int sd_device_monitor_filter_add_match_subsystem_devtype(sd_device_monitor *m, const char *subsystem, const char *devtype) {
+        _cleanup_free_ char *s = NULL, *d = NULL;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+
+        s = strdup(subsystem);
+        if (!s)
+                return -ENOMEM;
+
+        if (devtype) {
+                d = strdup(devtype);
+                if (!d)
+                        return -ENOMEM;
+        }
+
+        r = hashmap_ensure_allocated(&m->subsystem_filter, NULL);
+        if (r < 0)
+                return r;
+
+        r = hashmap_put(m->subsystem_filter, s, d);
+        if (r < 0)
+                return r;
+
+        s = d = NULL;
+        m->filter_uptodate = false;
+
+        return 0;
+}
+
+_public_ int sd_device_monitor_filter_add_match_tag(sd_device_monitor *m, const char *tag) {
+        assert_return(m, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        int r = set_put_strdup(&m->tag_filter, tag);
+        if (r > 0)
+                m->filter_uptodate = false;
+        return r;
+}
+
+_public_ int sd_device_monitor_filter_remove(sd_device_monitor *m) {
+        static const struct sock_fprog filter = { 0, NULL };
+
+        assert_return(m, -EINVAL);
+
+        m->subsystem_filter = hashmap_free_free_free(m->subsystem_filter);
+        m->tag_filter = set_free_free(m->tag_filter);
+
+        if (setsockopt(m->sock, SOL_SOCKET, SO_DETACH_FILTER, &filter, sizeof(filter)) < 0)
+                return -errno;
+
+        m->filter_uptodate = true;
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/device-private.c b/src/libsystemd/sd-device/device-private.c
new file mode 100644
index 0000000..9070dfb
--- /dev/null
+++ b/src/libsystemd/sd-device/device-private.c
@@ -0,0 +1,1017 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <ctype.h>
+#include <net/if.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-internal.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hashmap.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "nulstr-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "set.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strv.h"
+#include "strxcpyx.h"
+#include "tmpfile-util.h"
+#include "user-util.h"
+
+int device_add_property(sd_device *device, const char *key, const char *value) {
+        int r;
+
+        assert(device);
+        assert(key);
+
+        r = device_add_property_aux(device, key, value, false);
+        if (r < 0)
+                return r;
+
+        if (key[0] != '.') {
+                r = device_add_property_aux(device, key, value, true);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+void device_set_devlink_priority(sd_device *device, int priority) {
+        assert(device);
+
+        device->devlink_priority = priority;
+}
+
+void device_set_is_initialized(sd_device *device) {
+        assert(device);
+
+        device->is_initialized = true;
+}
+
+int device_ensure_usec_initialized(sd_device *device, sd_device *device_old) {
+        usec_t when;
+
+        assert(device);
+
+        if (device_old && device_old->usec_initialized > 0)
+                when = device_old->usec_initialized;
+        else
+                when = now(CLOCK_MONOTONIC);
+
+        return device_set_usec_initialized(device, when);
+}
+
+uint64_t device_get_properties_generation(sd_device *device) {
+        assert(device);
+
+        return device->properties_generation;
+}
+
+uint64_t device_get_tags_generation(sd_device *device) {
+        assert(device);
+
+        return device->tags_generation;
+}
+
+uint64_t device_get_devlinks_generation(sd_device *device) {
+        assert(device);
+
+        return device->devlinks_generation;
+}
+
+int device_get_devnode_mode(sd_device *device, mode_t *mode) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->devmode == (mode_t) -1)
+                return -ENOENT;
+
+        if (mode)
+                *mode = device->devmode;
+
+        return 0;
+}
+
+int device_get_devnode_uid(sd_device *device, uid_t *uid) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->devuid == (uid_t) -1)
+                return -ENOENT;
+
+        if (uid)
+                *uid = device->devuid;
+
+        return 0;
+}
+
+static int device_set_devuid(sd_device *device, const char *uid) {
+        unsigned u;
+        int r;
+
+        assert(device);
+        assert(uid);
+
+        r = safe_atou(uid, &u);
+        if (r < 0)
+                return r;
+
+        r = device_add_property_internal(device, "DEVUID", uid);
+        if (r < 0)
+                return r;
+
+        device->devuid = u;
+
+        return 0;
+}
+
+int device_get_devnode_gid(sd_device *device, gid_t *gid) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->devgid == (gid_t) -1)
+                return -ENOENT;
+
+        if (gid)
+                *gid = device->devgid;
+
+        return 0;
+}
+
+static int device_set_devgid(sd_device *device, const char *gid) {
+        unsigned g;
+        int r;
+
+        assert(device);
+        assert(gid);
+
+        r = safe_atou(gid, &g);
+        if (r < 0)
+                return r;
+
+        r = device_add_property_internal(device, "DEVGID", gid);
+        if (r < 0)
+                return r;
+
+        device->devgid = g;
+
+        return 0;
+}
+
+int device_get_action(sd_device *device, DeviceAction *action) {
+        assert(device);
+
+        if (device->action < 0)
+                return -ENOENT;
+
+        if (action)
+                *action = device->action;
+
+        return 0;
+}
+
+static int device_set_action(sd_device *device, const char *action) {
+        DeviceAction a;
+        int r;
+
+        assert(device);
+        assert(action);
+
+        a = device_action_from_string(action);
+        if (a < 0)
+                return -EINVAL;
+
+        r = device_add_property_internal(device, "ACTION", action);
+        if (r < 0)
+                return r;
+
+        device->action = a;
+
+        return 0;
+}
+
+int device_get_seqnum(sd_device *device, uint64_t *seqnum) {
+        assert(device);
+
+        if (device->seqnum == 0)
+                return -ENOENT;
+
+        if (seqnum)
+                *seqnum = device->seqnum;
+
+        return 0;
+}
+
+static int device_set_seqnum(sd_device *device, const char *str) {
+        uint64_t seqnum;
+        int r;
+
+        assert(device);
+        assert(str);
+
+        r = safe_atou64(str, &seqnum);
+        if (r < 0)
+                return r;
+        if (seqnum == 0)
+                return -EINVAL;
+
+        r = device_add_property_internal(device, "SEQNUM", str);
+        if (r < 0)
+                return r;
+
+        device->seqnum = seqnum;
+
+        return 0;
+}
+
+static int device_amend(sd_device *device, const char *key, const char *value) {
+        int r;
+
+        assert(device);
+        assert(key);
+        assert(value);
+
+        if (streq(key, "DEVPATH")) {
+                char *path;
+
+                path = strjoina("/sys", value);
+
+                /* the caller must verify or trust this data (e.g., if it comes from the kernel) */
+                r = device_set_syspath(device, path, false);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set syspath to '%s': %m", path);
+        } else if (streq(key, "SUBSYSTEM")) {
+                r = device_set_subsystem(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set subsystem to '%s': %m", value);
+        } else if (streq(key, "DEVTYPE")) {
+                r = device_set_devtype(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devtype to '%s': %m", value);
+        } else if (streq(key, "DEVNAME")) {
+                r = device_set_devname(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devname to '%s': %m", value);
+        } else if (streq(key, "USEC_INITIALIZED")) {
+                usec_t t;
+
+                r = safe_atou64(value, &t);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to parse timestamp '%s': %m", value);
+
+                r = device_set_usec_initialized(device, t);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set usec-initialized to '%s': %m", value);
+        } else if (streq(key, "DRIVER")) {
+                r = device_set_driver(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set driver to '%s': %m", value);
+        } else if (streq(key, "IFINDEX")) {
+                r = device_set_ifindex(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set ifindex to '%s': %m", value);
+        } else if (streq(key, "DEVMODE")) {
+                r = device_set_devmode(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devmode to '%s': %m", value);
+        } else if (streq(key, "DEVUID")) {
+                r = device_set_devuid(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devuid to '%s': %m", value);
+        } else if (streq(key, "DEVGID")) {
+                r = device_set_devgid(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devgid to '%s': %m", value);
+        } else if (streq(key, "ACTION")) {
+                r = device_set_action(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set action to '%s': %m", value);
+        } else if (streq(key, "SEQNUM")) {
+                r = device_set_seqnum(device, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set SEQNUM to '%s': %m", value);
+        } else if (streq(key, "DEVLINKS")) {
+                for (const char *p = value;;) {
+                        _cleanup_free_ char *word = NULL;
+
+                        /* udev rules may set escaped strings, and sd-device does not modify the input
+                         * strings. So, it is also necessary to keep the strings received through
+                         * sd-device-monitor. */
+                        r = extract_first_word(&p, &word, NULL, EXTRACT_RETAIN_ESCAPE);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = device_add_devlink(device, word);
+                        if (r < 0)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to add devlink '%s': %m", word);
+                }
+        } else if (STR_IN_SET(key, "TAGS", "CURRENT_TAGS")) {
+                for (const char *p = value;;) {
+                        _cleanup_free_ char *word = NULL;
+
+                        r = extract_first_word(&p, &word, ":", EXTRACT_DONT_COALESCE_SEPARATORS);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = device_add_tag(device, word, streq(key, "CURRENT_TAGS"));
+                        if (r < 0)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to add tag '%s': %m", word);
+                }
+        } else {
+                r = device_add_property_internal(device, key, value);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to add property '%s=%s': %m", key, value);
+        }
+
+        return 0;
+}
+
+static int device_append(sd_device *device, char *key, const char **_major, const char **_minor) {
+        const char *major = NULL, *minor = NULL;
+        char *value;
+        int r;
+
+        assert(device);
+        assert(key);
+        assert(_major);
+        assert(_minor);
+
+        value = strchr(key, '=');
+        if (!value)
+                return log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL),
+                                              "sd-device: Not a key-value pair: '%s'", key);
+
+        *value = '\0';
+
+        value++;
+
+        if (streq(key, "MAJOR"))
+                major = value;
+        else if (streq(key, "MINOR"))
+                minor = value;
+        else {
+                r = device_amend(device, key, value);
+                if (r < 0)
+                        return r;
+        }
+
+        if (major != 0)
+                *_major = major;
+
+        if (minor != 0)
+                *_minor = minor;
+
+        return 0;
+}
+
+void device_seal(sd_device *device) {
+        assert(device);
+
+        device->sealed = true;
+}
+
+static int device_verify(sd_device *device) {
+        assert(device);
+
+        if (!device->devpath || !device->subsystem || device->action < 0 || device->seqnum == 0)
+                return log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL),
+                                              "sd-device: Device created from strv or nulstr lacks devpath, subsystem, action or seqnum.");
+
+        device->sealed = true;
+
+        return 0;
+}
+
+int device_new_from_strv(sd_device **ret, char **strv) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        char **key;
+        const char *major = NULL, *minor = NULL;
+        int r;
+
+        assert(ret);
+        assert(strv);
+
+        r = device_new_aux(&device);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(key, strv) {
+                r = device_append(device, *key, &major, &minor);
+                if (r < 0)
+                        return r;
+        }
+
+        if (major) {
+                r = device_set_devnum(device, major, minor);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devnum %s:%s: %m", major, minor);
+        }
+
+        r = device_verify(device);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(device);
+
+        return 0;
+}
+
+int device_new_from_nulstr(sd_device **ret, uint8_t *nulstr, size_t len) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        const char *major = NULL, *minor = NULL;
+        unsigned i = 0;
+        int r;
+
+        assert(ret);
+        assert(nulstr);
+        assert(len);
+
+        r = device_new_aux(&device);
+        if (r < 0)
+                return r;
+
+        while (i < len) {
+                char *key;
+                const char *end;
+
+                key = (char*)&nulstr[i];
+                end = memchr(key, '\0', len - i);
+                if (!end)
+                        return log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL),
+                                                      "sd-device: Failed to parse nulstr");
+
+                i += end - key + 1;
+
+                /* netlink messages for some devices contain an unwanted newline at the end of value.
+                 * Let's drop the newline and remaining characters after the newline. */
+                truncate_nl(key);
+
+                r = device_append(device, key, &major, &minor);
+                if (r < 0)
+                        return r;
+        }
+
+        if (major) {
+                r = device_set_devnum(device, major, minor);
+                if (r < 0)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set devnum %s:%s: %m", major, minor);
+        }
+
+        r = device_verify(device);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(device);
+
+        return 0;
+}
+
+static int device_update_properties_bufs(sd_device *device) {
+        const char *val, *prop;
+        _cleanup_free_ char **buf_strv = NULL;
+        _cleanup_free_ uint8_t *buf_nulstr = NULL;
+        size_t allocated_nulstr = 0;
+        size_t nulstr_len = 0, num = 0, i = 0;
+
+        assert(device);
+
+        if (!device->properties_buf_outdated)
+                return 0;
+
+        FOREACH_DEVICE_PROPERTY(device, prop, val) {
+                size_t len = 0;
+
+                len = strlen(prop) + 1 + strlen(val);
+
+                buf_nulstr = GREEDY_REALLOC0(buf_nulstr, allocated_nulstr, nulstr_len + len + 2);
+                if (!buf_nulstr)
+                        return -ENOMEM;
+
+                strscpyl((char *)buf_nulstr + nulstr_len, len + 1, prop, "=", val, NULL);
+                nulstr_len += len + 1;
+                ++num;
+        }
+
+        /* build buf_strv from buf_nulstr */
+        buf_strv = new0(char *, num + 1);
+        if (!buf_strv)
+                return -ENOMEM;
+
+        NULSTR_FOREACH(val, (char*) buf_nulstr) {
+                buf_strv[i] = (char *) val;
+                assert(i < num);
+                i++;
+        }
+
+        free_and_replace(device->properties_nulstr, buf_nulstr);
+        device->properties_nulstr_len = nulstr_len;
+        free_and_replace(device->properties_strv, buf_strv);
+
+        device->properties_buf_outdated = false;
+
+        return 0;
+}
+
+int device_get_properties_nulstr(sd_device *device, const uint8_t **nulstr, size_t *len) {
+        int r;
+
+        assert(device);
+        assert(nulstr);
+        assert(len);
+
+        r = device_update_properties_bufs(device);
+        if (r < 0)
+                return r;
+
+        *nulstr = device->properties_nulstr;
+        *len = device->properties_nulstr_len;
+
+        return 0;
+}
+
+int device_get_properties_strv(sd_device *device, char ***strv) {
+        int r;
+
+        assert(device);
+        assert(strv);
+
+        r = device_update_properties_bufs(device);
+        if (r < 0)
+                return r;
+
+        *strv = device->properties_strv;
+
+        return 0;
+}
+
+int device_get_devlink_priority(sd_device *device, int *priority) {
+        int r;
+
+        assert(device);
+        assert(priority);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        *priority = device->devlink_priority;
+
+        return 0;
+}
+
+int device_get_watch_handle(sd_device *device, int *handle) {
+        int r;
+
+        assert(device);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->watch_handle < 0)
+                return -ENOENT;
+
+        if (handle)
+                *handle = device->watch_handle;
+
+        return 0;
+}
+
+void device_set_watch_handle(sd_device *device, int handle) {
+        assert(device);
+
+        device->watch_handle = handle;
+}
+
+int device_rename(sd_device *device, const char *name) {
+        _cleanup_free_ char *dirname = NULL;
+        const char *new_syspath, *interface;
+        int r;
+
+        assert(device);
+        assert(name);
+
+        dirname = dirname_malloc(device->syspath);
+        if (!dirname)
+                return -ENOMEM;
+
+        new_syspath = prefix_roota(dirname, name);
+
+        /* the user must trust that the new name is correct */
+        r = device_set_syspath(device, new_syspath, false);
+        if (r < 0)
+                return r;
+
+        r = sd_device_get_property_value(device, "INTERFACE", &interface);
+        if (r >= 0) {
+                /* like DEVPATH_OLD, INTERFACE_OLD is not saved to the db, but only stays around for the current event */
+                r = device_add_property_internal(device, "INTERFACE_OLD", interface);
+                if (r < 0)
+                        return r;
+
+                r = device_add_property_internal(device, "INTERFACE", name);
+                if (r < 0)
+                        return r;
+        } else if (r != -ENOENT)
+                return r;
+
+        return 0;
+}
+
+int device_shallow_clone(sd_device *old_device, sd_device **new_device) {
+        _cleanup_(sd_device_unrefp) sd_device *ret = NULL;
+        int r;
+
+        assert(old_device);
+        assert(new_device);
+
+        r = device_new_aux(&ret);
+        if (r < 0)
+                return r;
+
+        r = device_set_syspath(ret, old_device->syspath, false);
+        if (r < 0)
+                return r;
+
+        r = device_set_subsystem(ret, old_device->subsystem);
+        if (r < 0)
+                return r;
+
+        ret->devnum = old_device->devnum;
+
+        *new_device = TAKE_PTR(ret);
+
+        return 0;
+}
+
+int device_clone_with_db(sd_device *old_device, sd_device **new_device) {
+        _cleanup_(sd_device_unrefp) sd_device *ret = NULL;
+        int r;
+
+        assert(old_device);
+        assert(new_device);
+
+        r = device_shallow_clone(old_device, &ret);
+        if (r < 0)
+                return r;
+
+        r = device_read_db(ret);
+        if (r < 0)
+                return r;
+
+        ret->sealed = true;
+
+        *new_device = TAKE_PTR(ret);
+
+        return 0;
+}
+
+int device_new_from_synthetic_event(sd_device **new_device, const char *syspath, const char *action) {
+        _cleanup_(sd_device_unrefp) sd_device *ret = NULL;
+        int r;
+
+        assert(new_device);
+        assert(syspath);
+        assert(action);
+
+        r = sd_device_new_from_syspath(&ret, syspath);
+        if (r < 0)
+                return r;
+
+        r = device_read_uevent_file(ret);
+        if (r < 0)
+                return r;
+
+        r = device_set_action(ret, action);
+        if (r < 0)
+                return r;
+
+        *new_device = TAKE_PTR(ret);
+
+        return 0;
+}
+
+int device_new_from_stat_rdev(sd_device **ret, const struct stat *st) {
+        char type;
+
+        assert(ret);
+        assert(st);
+
+        if (S_ISBLK(st->st_mode))
+                type = 'b';
+        else if (S_ISCHR(st->st_mode))
+                type = 'c';
+        else
+                return -ENOTTY;
+
+        return sd_device_new_from_devnum(ret, type, st->st_rdev);
+}
+
+int device_copy_properties(sd_device *device_dst, sd_device *device_src) {
+        const char *property, *value;
+        int r;
+
+        assert(device_dst);
+        assert(device_src);
+
+        r = device_properties_prepare(device_src);
+        if (r < 0)
+                return r;
+
+        ORDERED_HASHMAP_FOREACH_KEY(value, property, device_src->properties_db) {
+                r = device_add_property_aux(device_dst, property, value, true);
+                if (r < 0)
+                        return r;
+        }
+
+        ORDERED_HASHMAP_FOREACH_KEY(value, property, device_src->properties) {
+                r = device_add_property_aux(device_dst, property, value, false);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+void device_cleanup_tags(sd_device *device) {
+        assert(device);
+
+        device->all_tags = set_free_free(device->all_tags);
+        device->current_tags = set_free_free(device->current_tags);
+        device->property_tags_outdated = true;
+        device->tags_generation++;
+}
+
+void device_cleanup_devlinks(sd_device *device) {
+        assert(device);
+
+        set_free_free(device->devlinks);
+        device->devlinks = NULL;
+        device->property_devlinks_outdated = true;
+        device->devlinks_generation++;
+}
+
+void device_remove_tag(sd_device *device, const char *tag) {
+        assert(device);
+        assert(tag);
+
+        free(set_remove(device->current_tags, tag));
+        device->property_tags_outdated = true;
+        device->tags_generation++;
+}
+
+static int device_tag(sd_device *device, const char *tag, bool add) {
+        const char *id;
+        char *path;
+        int r;
+
+        assert(device);
+        assert(tag);
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/tags/", tag, "/", id);
+
+        if (add) {
+                r = touch_file(path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, 0444);
+                if (r < 0)
+                        return r;
+        } else {
+                r = unlink(path);
+                if (r < 0 && errno != ENOENT)
+                        return -errno;
+        }
+
+        return 0;
+}
+
+int device_tag_index(sd_device *device, sd_device *device_old, bool add) {
+        const char *tag;
+        int r = 0, k;
+
+        if (add && device_old) {
+                /* delete possible left-over tags */
+                FOREACH_DEVICE_TAG(device_old, tag) {
+                        if (!sd_device_has_tag(device, tag)) {
+                                k = device_tag(device_old, tag, false);
+                                if (r >= 0 && k < 0)
+                                        r = k;
+                        }
+                }
+        }
+
+        FOREACH_DEVICE_TAG(device, tag) {
+                k = device_tag(device, tag, add);
+                if (r >= 0 && k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static bool device_has_info(sd_device *device) {
+        assert(device);
+
+        if (!set_isempty(device->devlinks))
+                return true;
+
+        if (device->devlink_priority != 0)
+                return true;
+
+        if (!ordered_hashmap_isempty(device->properties_db))
+                return true;
+
+        if (!set_isempty(device->all_tags))
+                return true;
+
+        if (!set_isempty(device->current_tags))
+                return true;
+
+        if (device->watch_handle >= 0)
+                return true;
+
+        return false;
+}
+
+void device_set_db_persist(sd_device *device) {
+        assert(device);
+
+        device->db_persist = true;
+}
+
+int device_update_db(sd_device *device) {
+        const char *id;
+        char *path;
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ char *path_tmp = NULL;
+        bool has_info;
+        int r;
+
+        assert(device);
+
+        has_info = device_has_info(device);
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/data/", id);
+
+        /* do not store anything for otherwise empty devices */
+        if (!has_info && major(device->devnum) == 0 && device->ifindex == 0) {
+                r = unlink(path);
+                if (r < 0 && errno != ENOENT)
+                        return -errno;
+
+                return 0;
+        }
+
+        /* write a database file */
+        r = mkdir_parents(path, 0755);
+        if (r < 0)
+                return r;
+
+        r = fopen_temporary(path, &f, &path_tmp);
+        if (r < 0)
+                return r;
+
+        /*
+         * set 'sticky' bit to indicate that we should not clean the
+         * database when we transition from initramfs to the real root
+         */
+        if (device->db_persist) {
+                r = fchmod(fileno(f), 01644);
+                if (r < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+        } else {
+                r = fchmod(fileno(f), 0644);
+                if (r < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+        }
+
+        if (has_info) {
+                const char *property, *value, *tag;
+
+                if (major(device->devnum) > 0) {
+                        const char *devlink;
+
+                        FOREACH_DEVICE_DEVLINK(device, devlink)
+                                fprintf(f, "S:%s\n", devlink + STRLEN("/dev/"));
+
+                        if (device->devlink_priority != 0)
+                                fprintf(f, "L:%i\n", device->devlink_priority);
+
+                        if (device->watch_handle >= 0)
+                                fprintf(f, "W:%i\n", device->watch_handle);
+                }
+
+                if (device->usec_initialized > 0)
+                        fprintf(f, "I:"USEC_FMT"\n", device->usec_initialized);
+
+                ORDERED_HASHMAP_FOREACH_KEY(value, property, device->properties_db)
+                        fprintf(f, "E:%s=%s\n", property, value);
+
+                FOREACH_DEVICE_TAG(device, tag)
+                        fprintf(f, "G:%s\n", tag); /* Any tag */
+
+                SET_FOREACH(tag, device->current_tags)
+                        fprintf(f, "Q:%s\n", tag); /* Current tag */
+
+                /* Always write the latest database version here, instead of the value stored in
+                 * device->database_version, as which may be 0. */
+                fputs("V:" STRINGIFY(LATEST_UDEV_DATABASE_VERSION) "\n", f);
+        }
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                goto fail;
+
+        r = rename(path_tmp, path);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        log_device_debug(device, "sd-device: Created %s file '%s' for '%s'", has_info ? "db" : "empty",
+                         path, device->devpath);
+
+        return 0;
+
+fail:
+        (void) unlink(path);
+        (void) unlink(path_tmp);
+
+        return log_device_debug_errno(device, r, "sd-device: Failed to create %s file '%s' for '%s'", has_info ? "db" : "empty", path, device->devpath);
+}
+
+int device_delete_db(sd_device *device) {
+        const char *id;
+        char *path;
+        int r;
+
+        assert(device);
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/data/", id);
+
+        r = unlink(path);
+        if (r < 0 && errno != ENOENT)
+                return -errno;
+
+        return 0;
+}
+
+static const char* const device_action_table[_DEVICE_ACTION_MAX] = {
+        [DEVICE_ACTION_ADD]     = "add",
+        [DEVICE_ACTION_REMOVE]  = "remove",
+        [DEVICE_ACTION_CHANGE]  = "change",
+        [DEVICE_ACTION_MOVE]    = "move",
+        [DEVICE_ACTION_ONLINE]  = "online",
+        [DEVICE_ACTION_OFFLINE] = "offline",
+        [DEVICE_ACTION_BIND]    = "bind",
+        [DEVICE_ACTION_UNBIND]  = "unbind",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(device_action, DeviceAction);
+
+void dump_device_action_table(void) {
+        DUMP_STRING_TABLE(device_action, DeviceAction, _DEVICE_ACTION_MAX);
+}
diff --git a/src/libsystemd/sd-device/device-private.h b/src/libsystemd/sd-device/device-private.h
new file mode 100644
index 0000000..db81934
--- /dev/null
+++ b/src/libsystemd/sd-device/device-private.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+
+#include "macro.h"
+
+typedef enum DeviceAction {
+        DEVICE_ACTION_ADD,
+        DEVICE_ACTION_REMOVE,
+        DEVICE_ACTION_CHANGE,
+        DEVICE_ACTION_MOVE,
+        DEVICE_ACTION_ONLINE,
+        DEVICE_ACTION_OFFLINE,
+        DEVICE_ACTION_BIND,
+        DEVICE_ACTION_UNBIND,
+        _DEVICE_ACTION_MAX,
+        _DEVICE_ACTION_INVALID = -1,
+} DeviceAction;
+
+int device_new_from_nulstr(sd_device **ret, uint8_t *nulstr, size_t len);
+int device_new_from_strv(sd_device **ret, char **strv);
+int device_new_from_stat_rdev(sd_device **ret, const struct stat *st);
+
+int device_get_id_filename(sd_device *device, const char **ret);
+
+int device_get_devlink_priority(sd_device *device, int *priority);
+int device_get_watch_handle(sd_device *device, int *handle);
+int device_get_devnode_mode(sd_device *device, mode_t *mode);
+int device_get_devnode_uid(sd_device *device, uid_t *uid);
+int device_get_devnode_gid(sd_device *device, gid_t *gid);
+int device_get_action(sd_device *device, DeviceAction *action);
+int device_get_seqnum(sd_device *device, uint64_t *seqnum);
+
+void device_seal(sd_device *device);
+void device_set_is_initialized(sd_device *device);
+void device_set_watch_handle(sd_device *device, int fd);
+void device_set_db_persist(sd_device *device);
+void device_set_devlink_priority(sd_device *device, int priority);
+int device_ensure_usec_initialized(sd_device *device, sd_device *device_old);
+int device_add_devlink(sd_device *device, const char *devlink);
+int device_add_property(sd_device *device, const char *property, const char *value);
+int device_add_tag(sd_device *device, const char *tag, bool both);
+void device_remove_tag(sd_device *device, const char *tag);
+void device_cleanup_tags(sd_device *device);
+void device_cleanup_devlinks(sd_device *device);
+
+uint64_t device_get_properties_generation(sd_device *device);
+uint64_t device_get_tags_generation(sd_device *device);
+uint64_t device_get_devlinks_generation(sd_device *device);
+
+int device_properties_prepare(sd_device *device);
+int device_get_properties_nulstr(sd_device *device, const uint8_t **nulstr, size_t *len);
+int device_get_properties_strv(sd_device *device, char ***strv);
+
+int device_rename(sd_device *device, const char *name);
+int device_shallow_clone(sd_device *old_device, sd_device **new_device);
+int device_clone_with_db(sd_device *old_device, sd_device **new_device);
+int device_copy_properties(sd_device *device_dst, sd_device *device_src);
+int device_new_from_synthetic_event(sd_device **new_device, const char *syspath, const char *action);
+
+int device_tag_index(sd_device *dev, sd_device *dev_old, bool add);
+int device_update_db(sd_device *device);
+int device_delete_db(sd_device *device);
+int device_read_db_internal_filename(sd_device *device, const char *filename); /* For fuzzer */
+int device_read_db_internal(sd_device *device, bool force);
+static inline int device_read_db(sd_device *device) {
+        return device_read_db_internal(device, false);
+}
+
+DeviceAction device_action_from_string(const char *s) _pure_;
+const char *device_action_to_string(DeviceAction a) _const_;
+void dump_device_action_table(void);
diff --git a/src/libsystemd/sd-device/device-util.h b/src/libsystemd/sd-device/device-util.h
new file mode 100644
index 0000000..1226209
--- /dev/null
+++ b/src/libsystemd/sd-device/device-util.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#define FOREACH_DEVICE_PROPERTY(device, key, value)                \
+        for (key = sd_device_get_property_first(device, &(value)); \
+             key;                                                  \
+             key = sd_device_get_property_next(device, &(value)))
+
+#define FOREACH_DEVICE_TAG(device, tag)             \
+        for (tag = sd_device_get_tag_first(device); \
+             tag;                                   \
+             tag = sd_device_get_tag_next(device))
+
+#define FOREACH_DEVICE_CURRENT_TAG(device, tag)             \
+        for (tag = sd_device_get_current_tag_first(device); \
+             tag;                                   \
+             tag = sd_device_get_current_tag_next(device))
+
+#define FOREACH_DEVICE_SYSATTR(device, attr)             \
+        for (attr = sd_device_get_sysattr_first(device); \
+             attr;                                       \
+             attr = sd_device_get_sysattr_next(device))
+
+#define FOREACH_DEVICE_DEVLINK(device, devlink)             \
+        for (devlink = sd_device_get_devlink_first(device); \
+             devlink;                                   \
+             devlink = sd_device_get_devlink_next(device))
+
+#define FOREACH_DEVICE(enumerator, device)                               \
+        for (device = sd_device_enumerator_get_device_first(enumerator); \
+             device;                                                     \
+             device = sd_device_enumerator_get_device_next(enumerator))
+
+#define FOREACH_SUBSYSTEM(enumerator, device)                               \
+        for (device = sd_device_enumerator_get_subsystem_first(enumerator); \
+             device;                                                        \
+             device = sd_device_enumerator_get_subsystem_next(enumerator))
+
+#define log_device_full_errno(device, level, error, ...)                \
+        ({                                                              \
+                const char *_sysname = NULL;                            \
+                sd_device *_d = (device);                               \
+                int _level = (level), _error = (error);                 \
+                                                                        \
+                if (_d && _unlikely_(log_get_max_level() >= LOG_PRI(_level))) \
+                        (void) sd_device_get_sysname(_d, &_sysname);    \
+                log_object_internal(_level, _error, PROJECT_FILE, __LINE__, __func__, \
+                                    _sysname ? "DEVICE=" : NULL, _sysname, \
+                                    NULL, NULL, __VA_ARGS__);           \
+        })
+
+#define log_device_full(device, level, ...) (void) log_device_full_errno(device, level, 0, __VA_ARGS__)
+
+#define log_device_debug(device, ...)   log_device_full_errno(device, LOG_DEBUG, 0, __VA_ARGS__)
+#define log_device_info(device, ...)    log_device_full(device, LOG_INFO, __VA_ARGS__)
+#define log_device_notice(device, ...)  log_device_full(device, LOG_NOTICE, __VA_ARGS__)
+#define log_device_warning(device, ...) log_device_full(device, LOG_WARNING, __VA_ARGS__)
+#define log_device_error(device, ...)   log_device_full(device, LOG_ERR, __VA_ARGS__)
+
+#define log_device_debug_errno(device, error, ...)   log_device_full_errno(device, LOG_DEBUG, error, __VA_ARGS__)
+#define log_device_info_errno(device, error, ...)    log_device_full_errno(device, LOG_INFO, error, __VA_ARGS__)
+#define log_device_notice_errno(device, error, ...)  log_device_full_errno(device, LOG_NOTICE, error, __VA_ARGS__)
+#define log_device_warning_errno(device, error, ...) log_device_full_errno(device, LOG_WARNING, error, __VA_ARGS__)
+#define log_device_error_errno(device, error, ...)   log_device_full_errno(device, LOG_ERR, error, __VA_ARGS__)
diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c
new file mode 100644
index 0000000..d1aa328
--- /dev/null
+++ b/src/libsystemd/sd-device/sd-device.c
@@ -0,0 +1,1996 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <ctype.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-internal.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hashmap.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "set.h"
+#include "socket-util.h"
+#include "stat-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "strxcpyx.h"
+#include "util.h"
+
+int device_new_aux(sd_device **ret) {
+        sd_device *device;
+
+        assert(ret);
+
+        device = new(sd_device, 1);
+        if (!device)
+                return -ENOMEM;
+
+        *device = (sd_device) {
+                .n_ref = 1,
+                .watch_handle = -1,
+                .devmode = (mode_t) -1,
+                .devuid = (uid_t) -1,
+                .devgid = (gid_t) -1,
+                .action = _DEVICE_ACTION_INVALID,
+        };
+
+        *ret = device;
+        return 0;
+}
+
+static sd_device *device_free(sd_device *device) {
+        assert(device);
+
+        sd_device_unref(device->parent);
+        free(device->syspath);
+        free(device->sysname);
+        free(device->devtype);
+        free(device->devname);
+        free(device->subsystem);
+        free(device->driver_subsystem);
+        free(device->driver);
+        free(device->id_filename);
+        free(device->properties_strv);
+        free(device->properties_nulstr);
+
+        ordered_hashmap_free_free_free(device->properties);
+        ordered_hashmap_free_free_free(device->properties_db);
+        hashmap_free_free_free(device->sysattr_values);
+        set_free(device->sysattrs);
+        set_free(device->all_tags);
+        set_free(device->current_tags);
+        set_free(device->devlinks);
+
+        return mfree(device);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device, sd_device, device_free);
+
+int device_add_property_aux(sd_device *device, const char *_key, const char *_value, bool db) {
+        OrderedHashmap **properties;
+
+        assert(device);
+        assert(_key);
+
+        if (db)
+                properties = &device->properties_db;
+        else
+                properties = &device->properties;
+
+        if (_value) {
+                _cleanup_free_ char *key = NULL, *value = NULL, *old_key = NULL, *old_value = NULL;
+                int r;
+
+                r = ordered_hashmap_ensure_allocated(properties, &string_hash_ops);
+                if (r < 0)
+                        return r;
+
+                key = strdup(_key);
+                if (!key)
+                        return -ENOMEM;
+
+                value = strdup(_value);
+                if (!value)
+                        return -ENOMEM;
+
+                old_value = ordered_hashmap_get2(*properties, key, (void**) &old_key);
+
+                r = ordered_hashmap_replace(*properties, key, value);
+                if (r < 0)
+                        return r;
+
+                key = NULL;
+                value = NULL;
+        } else {
+                _cleanup_free_ char *key = NULL;
+                _cleanup_free_ char *value = NULL;
+
+                value = ordered_hashmap_remove2(*properties, _key, (void**) &key);
+        }
+
+        if (!db) {
+                device->properties_generation++;
+                device->properties_buf_outdated = true;
+        }
+
+        return 0;
+}
+
+int device_set_syspath(sd_device *device, const char *_syspath, bool verify) {
+        _cleanup_free_ char *syspath = NULL;
+        const char *devpath;
+        int r;
+
+        assert(device);
+        assert(_syspath);
+
+        /* must be a subdirectory of /sys */
+        if (!path_startswith(_syspath, "/sys/"))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "sd-device: Syspath '%s' is not a subdirectory of /sys",
+                                       _syspath);
+
+        if (verify) {
+                r = chase_symlinks(_syspath, NULL, 0, &syspath, NULL);
+                if (r == -ENOENT)
+                        return -ENODEV; /* the device does not exist (any more?) */
+                if (r < 0)
+                        return log_debug_errno(r, "sd-device: Failed to get target of '%s': %m", _syspath);
+
+                if (!path_startswith(syspath, "/sys")) {
+                        _cleanup_free_ char *real_sys = NULL, *new_syspath = NULL;
+                        char *p;
+
+                        /* /sys is a symlink to somewhere sysfs is mounted on? In that case, we convert the path to real sysfs to "/sys". */
+                        r = chase_symlinks("/sys", NULL, 0, &real_sys, NULL);
+                        if (r < 0)
+                                return log_debug_errno(r, "sd-device: Failed to chase symlink /sys: %m");
+
+                        p = path_startswith(syspath, real_sys);
+                        if (!p)
+                                return log_debug_errno(SYNTHETIC_ERRNO(ENODEV),
+                                                       "sd-device: Canonicalized path '%s' does not starts with sysfs mount point '%s'",
+                                                       syspath, real_sys);
+
+                        new_syspath = path_join("/sys", p);
+                        if (!new_syspath)
+                                return -ENOMEM;
+
+                        free_and_replace(syspath, new_syspath);
+                        path_simplify(syspath, false);
+                }
+
+                if (path_startswith(syspath,  "/sys/devices/")) {
+                        char *path;
+
+                        /* all 'devices' require an 'uevent' file */
+                        path = strjoina(syspath, "/uevent");
+                        r = access(path, F_OK);
+                        if (r < 0) {
+                                if (errno == ENOENT)
+                                        /* this is not a valid device */
+                                        return -ENODEV;
+
+                                return log_debug_errno(errno, "sd-device: %s does not have an uevent file: %m", syspath);
+                        }
+                } else {
+                        /* everything else just needs to be a directory */
+                        if (!is_dir(syspath, false))
+                                return -ENODEV;
+                }
+        } else {
+                syspath = strdup(_syspath);
+                if (!syspath)
+                        return -ENOMEM;
+        }
+
+        devpath = syspath + STRLEN("/sys");
+
+        if (devpath[0] == '\0')
+                /* '/sys' alone is not a valid device path */
+                return -ENODEV;
+
+        r = device_add_property_internal(device, "DEVPATH", devpath);
+        if (r < 0)
+                return r;
+
+        free_and_replace(device->syspath, syspath);
+        device->devpath = devpath;
+        return 0;
+}
+
+_public_ int sd_device_new_from_syspath(sd_device **ret, const char *syspath) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(syspath, -EINVAL);
+
+        r = device_new_aux(&device);
+        if (r < 0)
+                return r;
+
+        r = device_set_syspath(device, syspath, true);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(device);
+        return 0;
+}
+
+_public_ int sd_device_new_from_devnum(sd_device **ret, char type, dev_t devnum) {
+        char *syspath;
+        char id[DECIMAL_STR_MAX(unsigned) * 2 + 1];
+
+        assert_return(ret, -EINVAL);
+        assert_return(IN_SET(type, 'b', 'c'), -EINVAL);
+
+        /* use /sys/dev/{block,char}/<maj>:<min> link */
+        xsprintf(id, "%u:%u", major(devnum), minor(devnum));
+
+        syspath = strjoina("/sys/dev/", (type == 'b' ? "block" : "char"), "/", id);
+
+        return sd_device_new_from_syspath(ret, syspath);
+}
+
+_public_ int sd_device_new_from_subsystem_sysname(sd_device **ret, const char *subsystem, const char *sysname) {
+        char *name, *syspath;
+        size_t len = 0;
+
+        assert_return(ret, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+        assert_return(sysname, -EINVAL);
+
+        if (streq(subsystem, "subsystem")) {
+                syspath = strjoina("/sys/subsystem/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+
+                syspath = strjoina("/sys/bus/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+
+                syspath = strjoina("/sys/class/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+        } else  if (streq(subsystem, "module")) {
+                syspath = strjoina("/sys/module/", sysname);
+                if (access(syspath, F_OK) >= 0)
+                        return sd_device_new_from_syspath(ret, syspath);
+        } else if (streq(subsystem, "drivers")) {
+                char subsys[PATH_MAX];
+                char *driver;
+
+                strscpy(subsys, sizeof(subsys), sysname);
+                driver = strchr(subsys, ':');
+                if (driver) {
+                        driver[0] = '\0';
+                        driver++;
+
+                        syspath = strjoina("/sys/subsystem/", subsys, "/drivers/", driver);
+                        if (access(syspath, F_OK) >= 0)
+                                return sd_device_new_from_syspath(ret, syspath);
+
+                        syspath = strjoina("/sys/bus/", subsys, "/drivers/", driver);
+                        if (access(syspath, F_OK) >= 0)
+                                return sd_device_new_from_syspath(ret, syspath);
+                }
+        }
+
+        /* translate sysname back to sysfs filename */
+        name = strdupa(sysname);
+        while (name[len] != '\0') {
+                if (name[len] == '/')
+                        name[len] = '!';
+
+                len++;
+        }
+
+        syspath = strjoina("/sys/subsystem/", subsystem, "/devices/", name);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        syspath = strjoina("/sys/bus/", subsystem, "/devices/", name);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        syspath = strjoina("/sys/class/", subsystem, "/", name);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        syspath = strjoina("/sys/firmware/", subsystem, "/", sysname);
+        if (access(syspath, F_OK) >= 0)
+                return sd_device_new_from_syspath(ret, syspath);
+
+        return -ENODEV;
+}
+
+int device_set_devtype(sd_device *device, const char *devtype) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        assert(device);
+        assert(devtype);
+
+        t = strdup(devtype);
+        if (!t)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "DEVTYPE", t);
+        if (r < 0)
+                return r;
+
+        return free_and_replace(device->devtype, t);
+}
+
+int device_set_ifindex(sd_device *device, const char *name) {
+        int r, ifindex;
+
+        assert(device);
+        assert(name);
+
+        ifindex = parse_ifindex(name);
+        if (ifindex < 0)
+                return ifindex;
+
+        r = device_add_property_internal(device, "IFINDEX", name);
+        if (r < 0)
+                return r;
+
+        device->ifindex = ifindex;
+
+        return 0;
+}
+
+int device_set_devname(sd_device *device, const char *devname) {
+        _cleanup_free_ char *t = NULL;
+        int r;
+
+        assert(device);
+        assert(devname);
+
+        if (devname[0] != '/')
+                t = strjoin("/dev/", devname);
+        else
+                t = strdup(devname);
+        if (!t)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "DEVNAME", t);
+        if (r < 0)
+                return r;
+
+        return free_and_replace(device->devname, t);
+}
+
+int device_set_devmode(sd_device *device, const char *_devmode) {
+        unsigned devmode;
+        int r;
+
+        assert(device);
+        assert(_devmode);
+
+        r = safe_atou(_devmode, &devmode);
+        if (r < 0)
+                return r;
+
+        if (devmode > 07777)
+                return -EINVAL;
+
+        r = device_add_property_internal(device, "DEVMODE", _devmode);
+        if (r < 0)
+                return r;
+
+        device->devmode = devmode;
+
+        return 0;
+}
+
+int device_set_devnum(sd_device *device, const char *major, const char *minor) {
+        unsigned maj = 0, min = 0;
+        int r;
+
+        assert(device);
+        assert(major);
+
+        r = safe_atou(major, &maj);
+        if (r < 0)
+                return r;
+        if (!maj)
+                return 0;
+
+        if (minor) {
+                r = safe_atou(minor, &min);
+                if (r < 0)
+                        return r;
+        }
+
+        r = device_add_property_internal(device, "MAJOR", major);
+        if (r < 0)
+                return r;
+
+        if (minor) {
+                r = device_add_property_internal(device, "MINOR", minor);
+                if (r < 0)
+                        return r;
+        }
+
+        device->devnum = makedev(maj, min);
+
+        return 0;
+}
+
+static int handle_uevent_line(sd_device *device, const char *key, const char *value, const char **major, const char **minor) {
+        int r;
+
+        assert(device);
+        assert(key);
+        assert(value);
+        assert(major);
+        assert(minor);
+
+        if (streq(key, "DEVTYPE")) {
+                r = device_set_devtype(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "IFINDEX")) {
+                r = device_set_ifindex(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "DEVNAME")) {
+                r = device_set_devname(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "DEVMODE")) {
+                r = device_set_devmode(device, value);
+                if (r < 0)
+                        return r;
+        } else if (streq(key, "MAJOR"))
+                *major = value;
+        else if (streq(key, "MINOR"))
+                *minor = value;
+        else {
+                r = device_add_property_internal(device, key, value);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int device_read_uevent_file(sd_device *device) {
+        _cleanup_free_ char *uevent = NULL;
+        const char *syspath, *key = NULL, *value = NULL, *major = NULL, *minor = NULL;
+        char *path;
+        size_t uevent_len;
+        unsigned i;
+        int r;
+
+        enum {
+                PRE_KEY,
+                KEY,
+                PRE_VALUE,
+                VALUE,
+                INVALID_LINE,
+        } state = PRE_KEY;
+
+        assert(device);
+
+        if (device->uevent_loaded || device->sealed)
+                return 0;
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        path = strjoina(syspath, "/uevent");
+
+        r = read_full_file(path, &uevent, &uevent_len);
+        if (r == -EACCES) {
+                /* empty uevent files may be write-only */
+                device->uevent_loaded = true;
+                return 0;
+        }
+        if (r == -ENOENT)
+                /* some devices may not have uevent files, see set_syspath() */
+                return 0;
+        if (r < 0)
+                return log_device_debug_errno(device, r, "sd-device: Failed to read uevent file '%s': %m", path);
+
+        device->uevent_loaded = true;
+
+        for (i = 0; i < uevent_len; i++)
+                switch (state) {
+                case PRE_KEY:
+                        if (!strchr(NEWLINE, uevent[i])) {
+                                key = &uevent[i];
+
+                                state = KEY;
+                        }
+
+                        break;
+                case KEY:
+                        if (uevent[i] == '=') {
+                                uevent[i] = '\0';
+
+                                state = PRE_VALUE;
+                        } else if (strchr(NEWLINE, uevent[i])) {
+                                uevent[i] = '\0';
+                                log_device_debug(device, "sd-device: Invalid uevent line '%s', ignoring", key);
+
+                                state = PRE_KEY;
+                        }
+
+                        break;
+                case PRE_VALUE:
+                        value = &uevent[i];
+                        state = VALUE;
+
+                        _fallthrough_; /* to handle empty property */
+                case VALUE:
+                        if (strchr(NEWLINE, uevent[i])) {
+                                uevent[i] = '\0';
+
+                                r = handle_uevent_line(device, key, value, &major, &minor);
+                                if (r < 0)
+                                        log_device_debug_errno(device, r, "sd-device: Failed to handle uevent entry '%s=%s', ignoring: %m", key, value);
+
+                                state = PRE_KEY;
+                        }
+
+                        break;
+                default:
+                        assert_not_reached("Invalid state when parsing uevent file");
+                }
+
+        if (major) {
+                r = device_set_devnum(device, major, minor);
+                if (r < 0)
+                        log_device_debug_errno(device, r, "sd-device: Failed to set 'MAJOR=%s' or 'MINOR=%s' from '%s', ignoring: %m", major, minor, path);
+        }
+
+        return 0;
+}
+
+_public_ int sd_device_get_ifindex(sd_device *device, int *ifindex) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (device->ifindex <= 0)
+                return -ENOENT;
+
+        if (ifindex)
+                *ifindex = device->ifindex;
+
+        return 0;
+}
+
+_public_ int sd_device_new_from_device_id(sd_device **ret, const char *id) {
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(id, -EINVAL);
+
+        switch (id[0]) {
+        case 'b':
+        case 'c': {
+                dev_t devt;
+
+                if (isempty(id))
+                        return -EINVAL;
+
+                r = parse_dev(id + 1, &devt);
+                if (r < 0)
+                        return r;
+
+                return sd_device_new_from_devnum(ret, id[0], devt);
+        }
+
+        case 'n': {
+                _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+                _cleanup_close_ int sk = -1;
+                struct ifreq ifr = {};
+                int ifindex;
+
+                r = ifr.ifr_ifindex = parse_ifindex(&id[1]);
+                if (r < 0)
+                        return r;
+
+                sk = socket_ioctl_fd();
+                if (sk < 0)
+                        return sk;
+
+                r = ioctl(sk, SIOCGIFNAME, &ifr);
+                if (r < 0)
+                        return -errno;
+
+                r = sd_device_new_from_subsystem_sysname(&device, "net", ifr.ifr_name);
+                if (r < 0)
+                        return r;
+
+                r = sd_device_get_ifindex(device, &ifindex);
+                if (r < 0)
+                        return r;
+
+                /* this is racey, so we might end up with the wrong device */
+                if (ifr.ifr_ifindex != ifindex)
+                        return -ENODEV;
+
+                *ret = TAKE_PTR(device);
+                return 0;
+        }
+
+        case '+': {
+                char subsys[PATH_MAX];
+                char *sysname;
+
+                (void) strscpy(subsys, sizeof(subsys), id + 1);
+                sysname = strchr(subsys, ':');
+                if (!sysname)
+                        return -EINVAL;
+
+                sysname[0] = '\0';
+                sysname++;
+
+                return sd_device_new_from_subsystem_sysname(ret, subsys, sysname);
+        }
+
+        default:
+                return -EINVAL;
+        }
+}
+
+_public_ int sd_device_get_syspath(sd_device *device, const char **ret) {
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        assert(path_startswith(device->syspath, "/sys/"));
+
+        *ret = device->syspath;
+
+        return 0;
+}
+
+static int device_new_from_child(sd_device **ret, sd_device *child) {
+        _cleanup_free_ char *path = NULL;
+        const char *subdir, *syspath;
+        int r;
+
+        assert(ret);
+        assert(child);
+
+        r = sd_device_get_syspath(child, &syspath);
+        if (r < 0)
+                return r;
+
+        path = strdup(syspath);
+        if (!path)
+                return -ENOMEM;
+        subdir = path + STRLEN("/sys");
+
+        for (;;) {
+                char *pos;
+
+                pos = strrchr(subdir, '/');
+                if (!pos || pos < subdir + 2)
+                        break;
+
+                *pos = '\0';
+
+                r = sd_device_new_from_syspath(ret, path);
+                if (r < 0)
+                        continue;
+
+                return 0;
+        }
+
+        return -ENODEV;
+}
+
+_public_ int sd_device_get_parent(sd_device *child, sd_device **ret) {
+
+        assert_return(ret, -EINVAL);
+        assert_return(child, -EINVAL);
+
+        if (!child->parent_set) {
+                child->parent_set = true;
+
+                (void) device_new_from_child(&child->parent, child);
+        }
+
+        if (!child->parent)
+                return -ENOENT;
+
+        *ret = child->parent;
+        return 0;
+}
+
+int device_set_subsystem(sd_device *device, const char *_subsystem) {
+        _cleanup_free_ char *subsystem = NULL;
+        int r;
+
+        assert(device);
+        assert(_subsystem);
+
+        subsystem = strdup(_subsystem);
+        if (!subsystem)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "SUBSYSTEM", subsystem);
+        if (r < 0)
+                return r;
+
+        device->subsystem_set = true;
+        return free_and_replace(device->subsystem, subsystem);
+}
+
+static int device_set_drivers_subsystem(sd_device *device, const char *_subsystem) {
+        _cleanup_free_ char *subsystem = NULL;
+        int r;
+
+        assert(device);
+        assert(_subsystem);
+        assert(*_subsystem);
+
+        subsystem = strdup(_subsystem);
+        if (!subsystem)
+                return -ENOMEM;
+
+        r = device_set_subsystem(device, "drivers");
+        if (r < 0)
+                return r;
+
+        return free_and_replace(device->driver_subsystem, subsystem);
+}
+
+_public_ int sd_device_get_subsystem(sd_device *device, const char **ret) {
+        const char *syspath, *drivers = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+        assert_return(device, -EINVAL);
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        if (!device->subsystem_set) {
+                _cleanup_free_ char *subsystem = NULL;
+                char *path;
+
+                /* read 'subsystem' link */
+                path = strjoina(syspath, "/subsystem");
+                r = readlink_value(path, &subsystem);
+                if (r >= 0)
+                        r = device_set_subsystem(device, subsystem);
+                /* use implicit names */
+                else if (path_startswith(device->devpath, "/module/"))
+                        r = device_set_subsystem(device, "module");
+                else if (!(drivers = strstr(syspath, "/drivers/")) &&
+                         PATH_STARTSWITH_SET(device->devpath, "/subsystem/",
+                                                              "/class/",
+                                                              "/bus/"))
+                        r = device_set_subsystem(device, "subsystem");
+                if (r < 0 && r != -ENOENT)
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set subsystem for %s: %m", device->devpath);
+
+                device->subsystem_set = true;
+        } else if (!device->driver_subsystem_set)
+                drivers = strstr(syspath, "/drivers/");
+
+        if (!device->driver_subsystem_set) {
+                if (drivers) {
+                        _cleanup_free_ char *subpath = NULL;
+
+                        subpath = strndup(syspath, drivers - syspath);
+                        if (!subpath)
+                                r = -ENOMEM;
+                        else {
+                                const char *subsys;
+
+                                subsys = strrchr(subpath, '/');
+                                if (!subsys)
+                                        r = -EINVAL;
+                                else
+                                        r = device_set_drivers_subsystem(device, subsys + 1);
+                        }
+                        if (r < 0 && r != -ENOENT)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to set subsystem for driver %s: %m", device->devpath);
+                }
+
+                device->driver_subsystem_set = true;
+        }
+
+        if (!device->subsystem)
+                return -ENOENT;
+
+        *ret = device->subsystem;
+        return 0;
+}
+
+_public_ int sd_device_get_devtype(sd_device *device, const char **devtype) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (!device->devtype)
+                return -ENOENT;
+
+        if (devtype)
+                *devtype = device->devtype;
+
+        return !!device->devtype;
+}
+
+_public_ int sd_device_get_parent_with_subsystem_devtype(sd_device *child, const char *subsystem, const char *devtype, sd_device **ret) {
+        sd_device *parent = NULL;
+        int r;
+
+        assert_return(child, -EINVAL);
+        assert_return(subsystem, -EINVAL);
+
+        r = sd_device_get_parent(child, &parent);
+        while (r >= 0) {
+                const char *parent_subsystem = NULL;
+                const char *parent_devtype = NULL;
+
+                (void) sd_device_get_subsystem(parent, &parent_subsystem);
+                if (streq_ptr(parent_subsystem, subsystem)) {
+                        if (!devtype)
+                                break;
+
+                        (void) sd_device_get_devtype(parent, &parent_devtype);
+                        if (streq_ptr(parent_devtype, devtype))
+                                break;
+                }
+                r = sd_device_get_parent(parent, &parent);
+        }
+
+        if (r < 0)
+                return r;
+
+        *ret = parent;
+        return 0;
+}
+
+_public_ int sd_device_get_devnum(sd_device *device, dev_t *devnum) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (major(device->devnum) <= 0)
+                return -ENOENT;
+
+        if (devnum)
+                *devnum = device->devnum;
+
+        return 0;
+}
+
+int device_set_driver(sd_device *device, const char *_driver) {
+        _cleanup_free_ char *driver = NULL;
+        int r;
+
+        assert(device);
+        assert(_driver);
+
+        driver = strdup(_driver);
+        if (!driver)
+                return -ENOMEM;
+
+        r = device_add_property_internal(device, "DRIVER", driver);
+        if (r < 0)
+                return r;
+
+        device->driver_set = true;
+        return free_and_replace(device->driver, driver);
+}
+
+_public_ int sd_device_get_driver(sd_device *device, const char **ret) {
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!device->driver_set) {
+                _cleanup_free_ char *driver = NULL;
+                const char *syspath;
+                char *path;
+                int r;
+
+                r = sd_device_get_syspath(device, &syspath);
+                if (r < 0)
+                        return r;
+
+                path = strjoina(syspath, "/driver");
+                r = readlink_value(path, &driver);
+                if (r >= 0) {
+                        r = device_set_driver(device, driver);
+                        if (r < 0)
+                                return log_device_debug_errno(device, r, "sd-device: Failed to set driver for %s: %m", device->devpath);
+                } else if (r == -ENOENT)
+                        device->driver_set = true;
+                else
+                        return log_device_debug_errno(device, r, "sd-device: Failed to set driver for %s: %m", device->devpath);
+        }
+
+        if (!device->driver)
+                return -ENOENT;
+
+        *ret = device->driver;
+        return 0;
+}
+
+_public_ int sd_device_get_devpath(sd_device *device, const char **devpath) {
+        assert_return(device, -EINVAL);
+        assert_return(devpath, -EINVAL);
+
+        assert(device->devpath);
+        assert(device->devpath[0] == '/');
+
+        *devpath = device->devpath;
+        return 0;
+}
+
+_public_ int sd_device_get_devname(sd_device *device, const char **devname) {
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(devname, -EINVAL);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        if (!device->devname)
+                return -ENOENT;
+
+        assert(path_startswith(device->devname, "/dev/"));
+
+        *devname = device->devname;
+        return 0;
+}
+
+static int device_set_sysname(sd_device *device) {
+        _cleanup_free_ char *sysname = NULL;
+        const char *sysnum = NULL;
+        const char *pos;
+        size_t len = 0;
+
+        if (!device->devpath)
+                return -EINVAL;
+
+        pos = strrchr(device->devpath, '/');
+        if (!pos)
+                return -EINVAL;
+        pos++;
+
+        /* devpath is not a root directory */
+        if (*pos == '\0' || pos <= device->devpath)
+                return -EINVAL;
+
+        sysname = strdup(pos);
+        if (!sysname)
+                return -ENOMEM;
+
+        /* some devices have '!' in their name, change that to '/' */
+        while (sysname[len] != '\0') {
+                if (sysname[len] == '!')
+                        sysname[len] = '/';
+
+                len++;
+        }
+
+        /* trailing number */
+        while (len > 0 && isdigit(sysname[--len]))
+                sysnum = &sysname[len];
+
+        if (len == 0)
+                sysnum = NULL;
+
+        device->sysname_set = true;
+        device->sysnum = sysnum;
+        return free_and_replace(device->sysname, sysname);
+}
+
+_public_ int sd_device_get_sysname(sd_device *device, const char **ret) {
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!device->sysname_set) {
+                r = device_set_sysname(device);
+                if (r < 0)
+                        return r;
+        }
+
+        assert_return(device->sysname, -ENOENT);
+
+        *ret = device->sysname;
+        return 0;
+}
+
+_public_ int sd_device_get_sysnum(sd_device *device, const char **ret) {
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!device->sysname_set) {
+                r = device_set_sysname(device);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!device->sysnum)
+                return -ENOENT;
+
+        *ret = device->sysnum;
+        return 0;
+}
+
+static bool is_valid_tag(const char *tag) {
+        assert(tag);
+
+        return !strchr(tag, ':') && !strchr(tag, ' ');
+}
+
+int device_add_tag(sd_device *device, const char *tag, bool both) {
+        int r, added;
+
+        assert(device);
+        assert(tag);
+
+        if (!is_valid_tag(tag))
+                return -EINVAL;
+
+        /* Definitely add to the "all" list of tags (i.e. the sticky list) */
+        added = set_put_strdup(&device->all_tags, tag);
+        if (added < 0)
+                return added;
+
+        /* And optionally, also add it to the current list of tags */
+        if (both) {
+                r = set_put_strdup(&device->current_tags, tag);
+                if (r < 0) {
+                        if (added > 0)
+                                (void) set_remove(device->all_tags, tag);
+
+                        return r;
+                }
+        }
+
+        device->tags_generation++;
+        device->property_tags_outdated = true;
+
+        return 0;
+}
+
+int device_add_devlink(sd_device *device, const char *devlink) {
+        int r;
+
+        assert(device);
+        assert(devlink);
+
+        r = set_put_strdup(&device->devlinks, devlink);
+        if (r < 0)
+                return r;
+
+        device->devlinks_generation++;
+        device->property_devlinks_outdated = true;
+
+        return 0;
+}
+
+static int device_add_property_internal_from_string(sd_device *device, const char *str) {
+        _cleanup_free_ char *key = NULL;
+        char *value;
+        int r;
+
+        assert(device);
+        assert(str);
+
+        key = strdup(str);
+        if (!key)
+                return -ENOMEM;
+
+        value = strchr(key, '=');
+        if (!value)
+                return -EINVAL;
+
+        *value = '\0';
+
+        if (isempty(++value))
+                value = NULL;
+
+        /* Add the property to both sd_device::properties and sd_device::properties_db,
+         * as this is called by only handle_db_line(). */
+        r = device_add_property_aux(device, key, value, false);
+        if (r < 0)
+                return r;
+
+        return device_add_property_aux(device, key, value, true);
+}
+
+int device_set_usec_initialized(sd_device *device, usec_t when) {
+        char s[DECIMAL_STR_MAX(usec_t)];
+        int r;
+
+        assert(device);
+
+        xsprintf(s, USEC_FMT, when);
+
+        r = device_add_property_internal(device, "USEC_INITIALIZED", s);
+        if (r < 0)
+                return r;
+
+        device->usec_initialized = when;
+        return 0;
+}
+
+static int handle_db_line(sd_device *device, char key, const char *value) {
+        char *path;
+        int r;
+
+        assert(device);
+        assert(value);
+
+        switch (key) {
+        case 'G': /* Any tag */
+        case 'Q': /* Current tag */
+                r = device_add_tag(device, value, key == 'Q');
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'S':
+                path = strjoina("/dev/", value);
+                r = device_add_devlink(device, path);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'E':
+                r = device_add_property_internal_from_string(device, value);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'I': {
+                usec_t t;
+
+                r = safe_atou64(value, &t);
+                if (r < 0)
+                        return r;
+
+                r = device_set_usec_initialized(device, t);
+                if (r < 0)
+                        return r;
+
+                break;
+        }
+        case 'L':
+                r = safe_atoi(value, &device->devlink_priority);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'W':
+                r = safe_atoi(value, &device->watch_handle);
+                if (r < 0)
+                        return r;
+
+                break;
+        case 'V':
+                r = safe_atou(value, &device->database_version);
+                if (r < 0)
+                        return r;
+
+                break;
+        default:
+                log_device_debug(device, "sd-device: Unknown key '%c' in device db, ignoring", key);
+        }
+
+        return 0;
+}
+
+int device_get_id_filename(sd_device *device, const char **ret) {
+        assert(device);
+        assert(ret);
+
+        if (!device->id_filename) {
+                _cleanup_free_ char *id = NULL;
+                const char *subsystem;
+                dev_t devnum;
+                int ifindex, r;
+
+                r = sd_device_get_subsystem(device, &subsystem);
+                if (r < 0)
+                        return r;
+
+                if (sd_device_get_devnum(device, &devnum) >= 0) {
+                        assert(subsystem);
+
+                        /* use dev_t — b259:131072, c254:0 */
+                        r = asprintf(&id, "%c%u:%u",
+                                     streq(subsystem, "block") ? 'b' : 'c',
+                                     major(devnum), minor(devnum));
+                        if (r < 0)
+                                return -ENOMEM;
+                } else if (sd_device_get_ifindex(device, &ifindex) >= 0) {
+                        /* use netdev ifindex — n3 */
+                        r = asprintf(&id, "n%u", (unsigned) ifindex);
+                        if (r < 0)
+                                return -ENOMEM;
+                } else {
+                        /* use $subsys:$sysname — pci:0000:00:1f.2
+                         * sysname() has '!' translated, get it from devpath
+                         */
+                        const char *sysname;
+
+                        sysname = basename(device->devpath);
+                        if (!sysname)
+                                return -EINVAL;
+
+                        if (!subsystem)
+                                return -EINVAL;
+
+
+                        if (streq(subsystem, "drivers"))
+                                /* the 'drivers' pseudo-subsystem is special, and needs the real subsystem
+                                 * encoded as well */
+                                id = strjoin("+drivers:", device->driver_subsystem, ":", sysname);
+                        else
+                                id = strjoin("+", subsystem, ":", sysname);
+                        if (!id)
+                                return -ENOMEM;
+                }
+
+                device->id_filename = TAKE_PTR(id);
+        }
+
+        *ret = device->id_filename;
+        return 0;
+}
+
+int device_read_db_internal_filename(sd_device *device, const char *filename) {
+        _cleanup_free_ char *db = NULL;
+        const char *value;
+        size_t db_len, i;
+        char key;
+        int r;
+
+        enum {
+                PRE_KEY,
+                KEY,
+                PRE_VALUE,
+                VALUE,
+                INVALID_LINE,
+        } state = PRE_KEY;
+
+        assert(device);
+        assert(filename);
+
+        r = read_full_file(filename, &db, &db_len);
+        if (r < 0) {
+                if (r == -ENOENT)
+                        return 0;
+
+                return log_device_debug_errno(device, r, "sd-device: Failed to read db '%s': %m", filename);
+        }
+
+        /* devices with a database entry are initialized */
+        device->is_initialized = true;
+
+        device->db_loaded = true;
+
+        for (i = 0; i < db_len; i++) {
+                switch (state) {
+                case PRE_KEY:
+                        if (!strchr(NEWLINE, db[i])) {
+                                key = db[i];
+
+                                state = KEY;
+                        }
+
+                        break;
+                case KEY:
+                        if (db[i] != ':') {
+                                log_device_debug(device, "sd-device: Invalid db entry with key '%c', ignoring", key);
+
+                                state = INVALID_LINE;
+                        } else {
+                                db[i] = '\0';
+
+                                state = PRE_VALUE;
+                        }
+
+                        break;
+                case PRE_VALUE:
+                        value = &db[i];
+
+                        state = VALUE;
+
+                        break;
+                case INVALID_LINE:
+                        if (strchr(NEWLINE, db[i]))
+                                state = PRE_KEY;
+
+                        break;
+                case VALUE:
+                        if (strchr(NEWLINE, db[i])) {
+                                db[i] = '\0';
+                                r = handle_db_line(device, key, value);
+                                if (r < 0)
+                                        log_device_debug_errno(device, r, "sd-device: Failed to handle db entry '%c:%s', ignoring: %m", key, value);
+
+                                state = PRE_KEY;
+                        }
+
+                        break;
+                default:
+                        return log_device_debug_errno(device, SYNTHETIC_ERRNO(EINVAL), "sd-device: invalid db syntax.");
+                }
+        }
+
+        return 0;
+}
+
+int device_read_db_internal(sd_device *device, bool force) {
+        const char *id, *path;
+        int r;
+
+        assert(device);
+
+        if (device->db_loaded || (!force && device->sealed))
+                return 0;
+
+        r = device_get_id_filename(device, &id);
+        if (r < 0)
+                return r;
+
+        path = strjoina("/run/udev/data/", id);
+
+        return device_read_db_internal_filename(device, path);
+}
+
+_public_ int sd_device_get_is_initialized(sd_device *device) {
+        int r;
+
+        assert_return(device, -EINVAL);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        return device->is_initialized;
+}
+
+_public_ int sd_device_get_usec_since_initialized(sd_device *device, uint64_t *usec) {
+        usec_t now_ts;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(usec, -EINVAL);
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (!device->is_initialized)
+                return -EBUSY;
+
+        if (!device->usec_initialized)
+                return -ENODATA;
+
+        now_ts = now(clock_boottime_or_monotonic());
+
+        if (now_ts < device->usec_initialized)
+                return -EIO;
+
+        *usec = now_ts - device->usec_initialized;
+        return 0;
+}
+
+_public_ const char *sd_device_get_tag_first(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        device->all_tags_iterator_generation = device->tags_generation;
+        device->all_tags_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->all_tags, &device->all_tags_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_tag_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        if (device->all_tags_iterator_generation != device->tags_generation)
+                return NULL;
+
+        (void) set_iterate(device->all_tags, &device->all_tags_iterator, &v);
+        return v;
+}
+
+static bool device_database_supports_current_tags(sd_device *device) {
+        assert(device);
+
+        (void) device_read_db(device);
+
+        /* The current tags (saved in Q field) feature is implemented in database version 1.
+         * If the database version is 0, then the tags (NOT current tags, saved in G field) are not
+         * sticky. Thus, we can safely bypass the operations for the current tags (Q) to tags (G). */
+
+        return device->database_version >= 1;
+}
+
+_public_ const char *sd_device_get_current_tag_first(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        if (!device_database_supports_current_tags(device))
+                return sd_device_get_tag_first(device);
+
+        (void) device_read_db(device);
+
+        device->current_tags_iterator_generation = device->tags_generation;
+        device->current_tags_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->current_tags, &device->current_tags_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_current_tag_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        if (!device_database_supports_current_tags(device))
+                return sd_device_get_tag_next(device);
+
+        (void) device_read_db(device);
+
+        if (device->current_tags_iterator_generation != device->tags_generation)
+                return NULL;
+
+        (void) set_iterate(device->current_tags, &device->current_tags_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_devlink_first(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        device->devlinks_iterator_generation = device->devlinks_generation;
+        device->devlinks_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->devlinks, &device->devlinks_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_devlink_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        (void) device_read_db(device);
+
+        if (device->devlinks_iterator_generation != device->devlinks_generation)
+                return NULL;
+
+        (void) set_iterate(device->devlinks, &device->devlinks_iterator, &v);
+        return v;
+}
+
+int device_properties_prepare(sd_device *device) {
+        int r;
+
+        assert(device);
+
+        r = device_read_uevent_file(device);
+        if (r < 0)
+                return r;
+
+        r = device_read_db(device);
+        if (r < 0)
+                return r;
+
+        if (device->property_devlinks_outdated) {
+                _cleanup_free_ char *devlinks = NULL;
+
+                r = set_strjoin(device->devlinks, " ", false, &devlinks);
+                if (r < 0)
+                        return r;
+
+                if (!isempty(devlinks)) {
+                        r = device_add_property_internal(device, "DEVLINKS", devlinks);
+                        if (r < 0)
+                                return r;
+                }
+
+                device->property_devlinks_outdated = false;
+        }
+
+        if (device->property_tags_outdated) {
+                _cleanup_free_ char *tags = NULL;
+
+                r = set_strjoin(device->all_tags, ":", true, &tags);
+                if (r < 0)
+                        return r;
+
+                if (!isempty(tags)) {
+                        r = device_add_property_internal(device, "TAGS", tags);
+                        if (r < 0)
+                                return r;
+                }
+
+                tags = mfree(tags);
+                r = set_strjoin(device->current_tags, ":", true, &tags);
+                if (r < 0)
+                        return r;
+
+                if (!isempty(tags)) {
+                        r = device_add_property_internal(device, "CURRENT_TAGS", tags);
+                        if (r < 0)
+                                return r;
+                }
+
+                device->property_tags_outdated = false;
+        }
+
+        return 0;
+}
+
+_public_ const char *sd_device_get_property_first(sd_device *device, const char **_value) {
+        const char *key;
+        int r;
+
+        assert_return(device, NULL);
+
+        r = device_properties_prepare(device);
+        if (r < 0)
+                return NULL;
+
+        device->properties_iterator_generation = device->properties_generation;
+        device->properties_iterator = ITERATOR_FIRST;
+
+        (void) ordered_hashmap_iterate(device->properties, &device->properties_iterator, (void**)_value, (const void**)&key);
+        return key;
+}
+
+_public_ const char *sd_device_get_property_next(sd_device *device, const char **_value) {
+        const char *key;
+        int r;
+
+        assert_return(device, NULL);
+
+        r = device_properties_prepare(device);
+        if (r < 0)
+                return NULL;
+
+        if (device->properties_iterator_generation != device->properties_generation)
+                return NULL;
+
+        (void) ordered_hashmap_iterate(device->properties, &device->properties_iterator, (void**)_value, (const void**)&key);
+        return key;
+}
+
+static int device_sysattrs_read_all_internal(sd_device *device, const char *subdir) {
+        _cleanup_free_ char *path_dir = NULL;
+        _cleanup_closedir_ DIR *dir = NULL;
+        struct dirent *dent;
+        const char *syspath;
+        int r;
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        if (subdir) {
+                _cleanup_free_ char *p = NULL;
+
+                p = path_join(syspath, subdir, "uevent");
+                if (!p)
+                        return -ENOMEM;
+
+                if (access(p, F_OK) >= 0)
+                        /* this is a child device, skipping */
+                        return 0;
+                if (errno != ENOENT) {
+                        log_device_debug_errno(device, errno, "sd-device: Failed to stat %s, ignoring subdir: %m", p);
+                        return 0;
+                }
+
+                path_dir = path_join(syspath, subdir);
+                if (!path_dir)
+                        return -ENOMEM;
+        }
+
+        dir = opendir(path_dir ?: syspath);
+        if (!dir)
+                return -errno;
+
+        FOREACH_DIRENT_ALL(dent, dir, return -errno) {
+                _cleanup_free_ char *path = NULL, *p = NULL;
+                struct stat statbuf;
+
+                if (dot_or_dot_dot(dent->d_name))
+                        continue;
+
+                /* only handle symlinks, regular files, and directories */
+                if (!IN_SET(dent->d_type, DT_LNK, DT_REG, DT_DIR))
+                        continue;
+
+                if (subdir) {
+                        p = path_join(subdir, dent->d_name);
+                        if (!p)
+                                return -ENOMEM;
+                }
+
+                if (dent->d_type == DT_DIR) {
+                        /* read subdirectory */
+                        r = device_sysattrs_read_all_internal(device, p ?: dent->d_name);
+                        if (r < 0)
+                                return r;
+
+                        continue;
+                }
+
+                path = path_join(syspath, p ?: dent->d_name);
+                if (!path)
+                        return -ENOMEM;
+
+                if (lstat(path, &statbuf) != 0)
+                        continue;
+
+                if (!(statbuf.st_mode & S_IRUSR))
+                        continue;
+
+                r = set_put_strdup(&device->sysattrs, p ?: dent->d_name);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int device_sysattrs_read_all(sd_device *device) {
+        int r;
+
+        assert(device);
+
+        if (device->sysattrs_read)
+                return 0;
+
+        r = device_sysattrs_read_all_internal(device, NULL);
+        if (r < 0)
+                return r;
+
+        device->sysattrs_read = true;
+
+        return 0;
+}
+
+_public_ const char *sd_device_get_sysattr_first(sd_device *device) {
+        void *v;
+        int r;
+
+        assert_return(device, NULL);
+
+        if (!device->sysattrs_read) {
+                r = device_sysattrs_read_all(device);
+                if (r < 0) {
+                        errno = -r;
+                        return NULL;
+                }
+        }
+
+        device->sysattrs_iterator = ITERATOR_FIRST;
+
+        (void) set_iterate(device->sysattrs, &device->sysattrs_iterator, &v);
+        return v;
+}
+
+_public_ const char *sd_device_get_sysattr_next(sd_device *device) {
+        void *v;
+
+        assert_return(device, NULL);
+
+        if (!device->sysattrs_read)
+                return NULL;
+
+        (void) set_iterate(device->sysattrs, &device->sysattrs_iterator, &v);
+        return v;
+}
+
+_public_ int sd_device_has_tag(sd_device *device, const char *tag) {
+        assert_return(device, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        (void) device_read_db(device);
+
+        return set_contains(device->all_tags, tag);
+}
+
+_public_ int sd_device_has_current_tag(sd_device *device, const char *tag) {
+        assert_return(device, -EINVAL);
+        assert_return(tag, -EINVAL);
+
+        if (!device_database_supports_current_tags(device))
+                return sd_device_has_tag(device, tag);
+
+        (void) device_read_db(device);
+
+        return set_contains(device->current_tags, tag);
+}
+
+_public_ int sd_device_get_property_value(sd_device *device, const char *key, const char **_value) {
+        char *value;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(key, -EINVAL);
+
+        r = device_properties_prepare(device);
+        if (r < 0)
+                return r;
+
+        value = ordered_hashmap_get(device->properties, key);
+        if (!value)
+                return -ENOENT;
+
+        if (_value)
+                *_value = value;
+        return 0;
+}
+
+/* replaces the value if it already exists */
+static int device_add_sysattr_value(sd_device *device, const char *_key, char *value) {
+        _cleanup_free_ char *key = NULL;
+        _cleanup_free_ char *value_old = NULL;
+        int r;
+
+        assert(device);
+        assert(_key);
+
+        r = hashmap_ensure_allocated(&device->sysattr_values, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        value_old = hashmap_remove2(device->sysattr_values, _key, (void **)&key);
+        if (!key) {
+                key = strdup(_key);
+                if (!key)
+                        return -ENOMEM;
+        }
+
+        r = hashmap_put(device->sysattr_values, key, value);
+        if (r < 0)
+                return r;
+        TAKE_PTR(key);
+
+        return 0;
+}
+
+static int device_get_sysattr_value(sd_device *device, const char *_key, const char **_value) {
+        const char *key = NULL, *value;
+
+        assert(device);
+        assert(_key);
+
+        value = hashmap_get2(device->sysattr_values, _key, (void **) &key);
+        if (!key)
+                return -ENOENT;
+
+        if (_value)
+                *_value = value;
+        return 0;
+}
+
+/* We cache all sysattr lookups. If an attribute does not exist, it is stored
+ * with a NULL value in the cache, otherwise the returned string is stored */
+_public_ int sd_device_get_sysattr_value(sd_device *device, const char *sysattr, const char **_value) {
+        _cleanup_free_ char *value = NULL;
+        const char *path, *syspath, *cached_value = NULL;
+        struct stat statbuf;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(sysattr, -EINVAL);
+
+        /* look for possibly already cached result */
+        r = device_get_sysattr_value(device, sysattr, &cached_value);
+        if (r != -ENOENT) {
+                if (r < 0)
+                        return r;
+
+                if (!cached_value)
+                        /* we looked up the sysattr before and it did not exist */
+                        return -ENOENT;
+
+                if (_value)
+                        *_value = cached_value;
+
+                return 0;
+        }
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        path = prefix_roota(syspath, sysattr);
+        r = lstat(path, &statbuf);
+        if (r < 0) {
+                /* remember that we could not access the sysattr */
+                r = device_add_sysattr_value(device, sysattr, NULL);
+                if (r < 0)
+                        return r;
+
+                return -ENOENT;
+        } else if (S_ISLNK(statbuf.st_mode)) {
+                /* Some core links return only the last element of the target path,
+                 * these are just values, the paths should not be exposed. */
+                if (STR_IN_SET(sysattr, "driver", "subsystem", "module")) {
+                        r = readlink_value(path, &value);
+                        if (r < 0)
+                                return r;
+                } else
+                        return -EINVAL;
+        } else if (S_ISDIR(statbuf.st_mode)) {
+                /* skip directories */
+                return -EINVAL;
+        } else if (!(statbuf.st_mode & S_IRUSR)) {
+                /* skip non-readable files */
+                return -EPERM;
+        } else {
+                size_t size;
+
+                /* read attribute value */
+                r = read_full_virtual_file(path, &value, &size);
+                if (r < 0)
+                        return r;
+
+                /* drop trailing newlines */
+                while (size > 0 && value[--size] == '\n')
+                        value[size] = '\0';
+        }
+
+        r = device_add_sysattr_value(device, sysattr, value);
+        if (r < 0)
+                return r;
+
+        *_value = TAKE_PTR(value);
+
+        return 0;
+}
+
+static void device_remove_sysattr_value(sd_device *device, const char *_key) {
+        _cleanup_free_ char *key = NULL;
+
+        assert(device);
+        assert(_key);
+
+        free(hashmap_remove2(device->sysattr_values, _key, (void **) &key));
+}
+
+/* set the attribute and save it in the cache. If a NULL value is passed the
+ * attribute is cleared from the cache */
+_public_ int sd_device_set_sysattr_value(sd_device *device, const char *sysattr, const char *_value) {
+        _cleanup_free_ char *value = NULL;
+        const char *syspath, *path;
+        size_t len;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(sysattr, -EINVAL);
+
+        if (!_value) {
+                device_remove_sysattr_value(device, sysattr);
+                return 0;
+        }
+
+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
+        path = prefix_roota(syspath, sysattr);
+
+        len = strlen(_value);
+
+        /* drop trailing newlines */
+        while (len > 0 && _value[len - 1] == '\n')
+                len --;
+
+        /* value length is limited to 4k */
+        if (len > 4096)
+                return -EINVAL;
+
+        value = strndup(_value, len);
+        if (!value)
+                return -ENOMEM;
+
+        r = write_string_file(path, value, WRITE_STRING_FILE_DISABLE_BUFFER | WRITE_STRING_FILE_NOFOLLOW);
+        if (r < 0) {
+                if (r == -ELOOP)
+                        return -EINVAL;
+                if (r == -EISDIR)
+                        return r;
+
+                r = free_and_strdup(&value, "");
+                if (r < 0)
+                        return r;
+
+                r = device_add_sysattr_value(device, sysattr, value);
+                if (r < 0)
+                        return r;
+                TAKE_PTR(value);
+
+                return -ENXIO;
+        }
+
+        r = device_add_sysattr_value(device, sysattr, value);
+        if (r < 0)
+                return r;
+        TAKE_PTR(value);
+
+        return 0;
+}
+
+_public_ int sd_device_set_sysattr_valuef(sd_device *device, const char *sysattr, const char *format, ...) {
+        _cleanup_free_ char *value = NULL;
+        va_list ap;
+        int r;
+
+        assert_return(device, -EINVAL);
+        assert_return(sysattr, -EINVAL);
+
+        if (!format) {
+                device_remove_sysattr_value(device, sysattr);
+                return 0;
+        }
+
+        va_start(ap, format);
+        r = vasprintf(&value, format, ap);
+        va_end(ap);
+
+        if (r < 0)
+                return -ENOMEM;
+
+        return sd_device_set_sysattr_value(device, sysattr, value);
+}
diff --git a/src/libsystemd/sd-device/test-sd-device-monitor.c b/src/libsystemd/sd-device/test-sd-device-monitor.c
new file mode 100644
index 0000000..fddd1c1
--- /dev/null
+++ b/src/libsystemd/sd-device/test-sd-device-monitor.c
@@ -0,0 +1,218 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "sd-device.h"
+#include "sd-event.h"
+
+#include "device-monitor-private.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "macro.h"
+#include "string-util.h"
+#include "tests.h"
+#include "util.h"
+#include "virt.h"
+
+static int monitor_handler(sd_device_monitor *m, sd_device *d, void *userdata) {
+        const char *s, *syspath = userdata;
+
+        assert_se(sd_device_get_syspath(d, &s) >= 0);
+        assert_se(streq(s, syspath));
+
+        return sd_event_exit(sd_device_monitor_get_event(m), 100);
+}
+
+static int test_receive_device_fail(void) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        _cleanup_(sd_device_unrefp) sd_device *loopback = NULL;
+        const char *syspath;
+        int r;
+
+        log_info("/* %s */", __func__);
+
+        /* Try to send device with invalid action and without seqnum. */
+        assert_se(sd_device_new_from_syspath(&loopback, "/sys/class/net/lo") >= 0);
+        assert_se(device_add_property(loopback, "ACTION", "hoge") >= 0);
+
+        assert_se(sd_device_get_syspath(loopback, &syspath) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        /* Do not use assert_se() here. */
+        r = device_monitor_send_device(monitor_server, monitor_client, loopback);
+        if (r < 0)
+                return log_error_errno(r, "Failed to send loopback device: %m");
+
+        assert_se(sd_event_run(sd_device_monitor_get_event(monitor_client), 0) >= 0);
+
+        return 0;
+}
+
+static void test_send_receive_one(sd_device *device, bool subsystem_filter, bool tag_filter, bool use_bpf) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        const char *syspath, *subsystem, *tag, *devtype = NULL;
+
+        log_device_info(device, "/* %s(subsystem_filter=%s, tag_filter=%s, use_bpf=%s) */", __func__,
+                        true_false(subsystem_filter), true_false(tag_filter), true_false(use_bpf));
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        if (subsystem_filter) {
+                assert_se(sd_device_get_subsystem(device, &subsystem) >= 0);
+                (void) sd_device_get_devtype(device, &devtype);
+                assert_se(sd_device_monitor_filter_add_match_subsystem_devtype(monitor_client, subsystem, devtype) >= 0);
+        }
+
+        if (tag_filter)
+                FOREACH_DEVICE_TAG(device, tag)
+                        assert_se(sd_device_monitor_filter_add_match_tag(monitor_client, tag) >= 0);
+
+        if ((subsystem_filter || tag_filter) && use_bpf)
+                assert_se(sd_device_monitor_filter_update(monitor_client) >= 0);
+
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_loop(sd_device_monitor_get_event(monitor_client)) == 100);
+}
+
+static void test_subsystem_filter(sd_device *device) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        const char *syspath, *subsystem, *p, *s;
+        sd_device *d;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+        assert_se(sd_device_get_subsystem(device, &subsystem) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_filter_add_match_subsystem_devtype(monitor_client, subsystem, NULL) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_add_match_subsystem(e, subsystem, false) >= 0);
+        FOREACH_DEVICE(e, d) {
+                assert_se(sd_device_get_syspath(d, &p) >= 0);
+                assert_se(sd_device_get_subsystem(d, &s) >= 0);
+
+                log_info("Sending device subsystem:%s syspath:%s", s, p);
+                assert_se(device_monitor_send_device(monitor_server, monitor_client, d) >= 0);
+        }
+
+        log_info("Sending device subsystem:%s syspath:%s", subsystem, syspath);
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_loop(sd_device_monitor_get_event(monitor_client)) == 100);
+}
+
+static void test_sd_device_monitor_filter_remove(sd_device *device) {
+        _cleanup_(sd_device_monitor_unrefp) sd_device_monitor *monitor_server = NULL, *monitor_client = NULL;
+        const char *syspath;
+
+        log_device_info(device, "/* %s */", __func__);
+
+        assert_se(sd_device_get_syspath(device, &syspath) >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_server, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(sd_device_monitor_start(monitor_server, NULL, NULL) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_server), "sender") >= 0);
+
+        assert_se(device_monitor_new_full(&monitor_client, MONITOR_GROUP_NONE, -1) >= 0);
+        assert_se(device_monitor_allow_unicast_sender(monitor_client, monitor_server) >= 0);
+        assert_se(sd_device_monitor_start(monitor_client, monitor_handler, (void *) syspath) >= 0);
+        assert_se(sd_event_source_set_description(sd_device_monitor_get_event_source(monitor_client), "receiver") >= 0);
+
+        assert_se(sd_device_monitor_filter_add_match_subsystem_devtype(monitor_client, "hoge", NULL) >= 0);
+        assert_se(sd_device_monitor_filter_update(monitor_client) >= 0);
+
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_run(sd_device_monitor_get_event(monitor_client), 0) >= 0);
+
+        assert_se(sd_device_monitor_filter_remove(monitor_client) >= 0);
+
+        assert_se(device_monitor_send_device(monitor_server, monitor_client, device) >= 0);
+        assert_se(sd_event_loop(sd_device_monitor_get_event(monitor_client)) == 100);
+}
+
+static void test_device_copy_properties(sd_device *device) {
+        _cleanup_(sd_device_unrefp) sd_device *copy = NULL;
+
+        assert_se(device_shallow_clone(device, &copy) >= 0);
+        assert_se(device_copy_properties(copy, device) >= 0);
+
+        test_send_receive_one(copy, false, false, false);
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_device_unrefp) sd_device *loopback = NULL, *sda = NULL;
+        int r;
+
+        test_setup_logging(LOG_INFO);
+
+        if (getuid() != 0)
+                return log_tests_skipped("not root");
+
+        r = test_receive_device_fail();
+        if (r < 0) {
+                assert_se(r == -EPERM && detect_container() > 0);
+                return log_tests_skipped("Running in container? Skipping remaining tests");
+        }
+
+        assert_se(sd_device_new_from_syspath(&loopback, "/sys/class/net/lo") >= 0);
+        assert_se(device_add_property(loopback, "ACTION", "add") >= 0);
+        assert_se(device_add_property(loopback, "SEQNUM", "10") >= 0);
+
+        test_send_receive_one(loopback, false, false, false);
+        test_send_receive_one(loopback,  true, false, false);
+        test_send_receive_one(loopback, false,  true, false);
+        test_send_receive_one(loopback,  true,  true, false);
+        test_send_receive_one(loopback,  true, false,  true);
+        test_send_receive_one(loopback, false,  true,  true);
+        test_send_receive_one(loopback,  true,  true,  true);
+
+        test_subsystem_filter(loopback);
+        test_sd_device_monitor_filter_remove(loopback);
+        test_device_copy_properties(loopback);
+
+        r = sd_device_new_from_subsystem_sysname(&sda, "block", "sda");
+        if (r < 0) {
+                log_info_errno(r, "Failed to create sd_device for sda, skipping remaining tests: %m");
+                return 0;
+        }
+
+        assert_se(device_add_property(sda, "ACTION", "change") >= 0);
+        assert_se(device_add_property(sda, "SEQNUM", "11") >= 0);
+
+        test_send_receive_one(sda, false, false, false);
+        test_send_receive_one(sda,  true, false, false);
+        test_send_receive_one(sda, false,  true, false);
+        test_send_receive_one(sda,  true,  true, false);
+        test_send_receive_one(sda,  true, false,  true);
+        test_send_receive_one(sda, false,  true,  true);
+        test_send_receive_one(sda,  true,  true,  true);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-sd-device-thread.c b/src/libsystemd/sd-device/test-sd-device-thread.c
new file mode 100644
index 0000000..6f30155
--- /dev/null
+++ b/src/libsystemd/sd-device/test-sd-device-thread.c
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sd-device.h"
+
+#include "device-util.h"
+#include "macro.h"
+
+static void* thread(void *p) {
+        sd_device **d = p;
+
+        assert_se(!(*d = sd_device_unref(*d)));
+
+        return NULL;
+}
+
+int main(int argc, char *argv[]) {
+        sd_device *loopback;
+        pthread_t t;
+        const char *key, *value;
+
+        assert_se(unsetenv("SYSTEMD_MEMPOOL") == 0);
+
+        assert_se(sd_device_new_from_syspath(&loopback, "/sys/class/net/lo") >= 0);
+
+        FOREACH_DEVICE_PROPERTY(loopback, key, value)
+                printf("%s=%s\n", key, value);
+
+        assert_se(pthread_create(&t, NULL, thread, &loopback) == 0);
+        assert_se(pthread_join(t, NULL) == 0);
+
+        assert_se(!loopback);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-sd-device.c b/src/libsystemd/sd-device/test-sd-device.c
new file mode 100644
index 0000000..9f48d2b
--- /dev/null
+++ b/src/libsystemd/sd-device/test-sd-device.c
@@ -0,0 +1,172 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "device-enumerator-private.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "hashmap.h"
+#include "string-util.h"
+#include "tests.h"
+#include "time-util.h"
+
+static void test_sd_device_one(sd_device *d) {
+        const char *syspath, *subsystem, *val;
+        dev_t devnum;
+        usec_t usec;
+        int i, r;
+
+        assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+
+        r = sd_device_get_subsystem(d, &subsystem);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        r = sd_device_get_devtype(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        r = sd_device_get_devnum(d, &devnum);
+        assert_se((r >= 0 && major(devnum) > 0) || r == -ENOENT);
+
+        r = sd_device_get_ifindex(d, &i);
+        assert_se((r >= 0 && i > 0) || r == -ENOENT);
+
+        r = sd_device_get_driver(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        assert_se(sd_device_get_devpath(d, &val) >= 0);
+
+        r = sd_device_get_devname(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        assert_se(sd_device_get_sysname(d, &val) >= 0);
+
+        r = sd_device_get_sysnum(d, &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        i = sd_device_get_is_initialized(d);
+        assert_se(i >= 0);
+        if (i > 0) {
+                r = sd_device_get_usec_since_initialized(d, &usec);
+                assert_se((r >= 0 && usec > 0) || r == -ENODATA);
+        }
+
+        r = sd_device_get_sysattr_value(d, "name_assign_type", &val);
+        assert_se(r >= 0 || IN_SET(r, -ENOENT, -EINVAL));
+
+        r = sd_device_get_property_value(d, "ID_NET_DRIVER", &val);
+        assert_se(r >= 0 || r == -ENOENT);
+
+        log_info("syspath:%s subsystem:%s initialized:%s", syspath, strna(subsystem), yes_no(i));
+}
+
+static void test_sd_device_enumerator_devices(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_allow_uninitialized(e) >= 0);
+        FOREACH_DEVICE(e, d)
+                test_sd_device_one(d);
+}
+
+static void test_sd_device_enumerator_subsystems(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_allow_uninitialized(e) >= 0);
+        FOREACH_SUBSYSTEM(e, d)
+                test_sd_device_one(d);
+}
+
+static unsigned test_sd_device_enumerator_filter_subsystem_one(const char *subsystem, Hashmap *h) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d, *t;
+        unsigned n_new_dev = 0;
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_add_match_subsystem(e, subsystem, true) >= 0);
+
+        FOREACH_DEVICE(e, d) {
+                const char *syspath;
+
+                assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+                t = hashmap_remove(h, syspath);
+                assert_se(!sd_device_unref(t));
+
+                if (t)
+                        log_debug("Removed subsystem:%s syspath:%s", subsystem, syspath);
+                else {
+                        log_warning("New device found: subsystem:%s syspath:%s", subsystem, syspath);
+                        n_new_dev++;
+                }
+        }
+
+        /* Assume no device is unplugged. */
+        assert_se(hashmap_isempty(h));
+
+        return n_new_dev;
+}
+
+static void test_sd_device_enumerator_filter_subsystem(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        _cleanup_(hashmap_freep) Hashmap *subsystems;
+        unsigned n_new_dev = 0;
+        sd_device *d;
+        Hashmap *h;
+        char *s;
+
+        log_info("/* %s */", __func__);
+
+        assert_se(subsystems = hashmap_new(&string_hash_ops));
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+
+        FOREACH_DEVICE(e, d) {
+                const char *syspath, *subsystem;
+                int r;
+
+                assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+
+                r = sd_device_get_subsystem(d, &subsystem);
+                assert_se(r >= 0 || r == -ENOENT);
+                if (r < 0)
+                        continue;
+
+                h = hashmap_get(subsystems, subsystem);
+                if (!h) {
+                        char *str;
+                        assert_se(str = strdup(subsystem));
+                        assert_se(h = hashmap_new(&string_hash_ops));
+                        assert_se(hashmap_put(subsystems, str, h) >= 0);
+                }
+
+                assert_se(hashmap_put(h, syspath, d) >= 0);
+                assert_se(sd_device_ref(d));
+
+                log_debug("Added subsystem:%s syspath:%s", subsystem, syspath);
+        }
+
+        while ((h = hashmap_steal_first_key_and_value(subsystems, (void**) &s))) {
+                n_new_dev += test_sd_device_enumerator_filter_subsystem_one(s, h);
+                hashmap_free(h);
+                free(s);
+        }
+
+        if (n_new_dev > 0)
+                log_warning("%u new device is found in re-scan", n_new_dev);
+
+        /* Assume that not so many devices are plugged. */
+        assert_se(n_new_dev <= 10);
+}
+
+int main(int argc, char **argv) {
+        test_setup_logging(LOG_INFO);
+
+        test_sd_device_enumerator_devices();
+        test_sd_device_enumerator_subsystems();
+        test_sd_device_enumerator_filter_subsystem();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-device/test-udev-device-thread.c b/src/libsystemd/sd-device/test-udev-device-thread.c
new file mode 100644
index 0000000..a493152
--- /dev/null
+++ b/src/libsystemd/sd-device/test-udev-device-thread.c
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libudev.h"
+
+#include "macro.h"
+
+static void* thread(void *p) {
+        struct udev_device **d = p;
+
+        assert_se(!(*d = udev_device_unref(*d)));
+
+        return NULL;
+}
+
+int main(int argc, char *argv[]) {
+        struct udev_device *loopback;
+        pthread_t t;
+
+        assert_se(unsetenv("SYSTEMD_MEMPOOL") == 0);
+
+        assert_se(loopback = udev_device_new_from_syspath(NULL, "/sys/class/net/lo"));
+
+        assert_se(udev_device_get_properties_list_entry(loopback));
+
+        assert_se(pthread_create(&t, NULL, thread, &loopback) == 0);
+        assert_se(pthread_join(t, NULL) == 0);
+
+        assert_se(!loopback);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-event/event-source.h b/src/libsystemd/sd-event/event-source.h
new file mode 100644
index 0000000..62d0718
--- /dev/null
+++ b/src/libsystemd/sd-event/event-source.h
@@ -0,0 +1,213 @@
+#pragma once
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <sys/wait.h>
+
+#include "sd-event.h"
+
+#include "fs-util.h"
+#include "hashmap.h"
+#include "list.h"
+#include "prioq.h"
+
+typedef enum EventSourceType {
+        SOURCE_IO,
+        SOURCE_TIME_REALTIME,
+        SOURCE_TIME_BOOTTIME,
+        SOURCE_TIME_MONOTONIC,
+        SOURCE_TIME_REALTIME_ALARM,
+        SOURCE_TIME_BOOTTIME_ALARM,
+        SOURCE_SIGNAL,
+        SOURCE_CHILD,
+        SOURCE_DEFER,
+        SOURCE_POST,
+        SOURCE_EXIT,
+        SOURCE_WATCHDOG,
+        SOURCE_INOTIFY,
+        _SOURCE_EVENT_SOURCE_TYPE_MAX,
+        _SOURCE_EVENT_SOURCE_TYPE_INVALID = -1
+} EventSourceType;
+
+/* All objects we use in epoll events start with this value, so that
+ * we know how to dispatch it */
+typedef enum WakeupType {
+        WAKEUP_NONE,
+        WAKEUP_EVENT_SOURCE, /* either I/O or pidfd wakeup */
+        WAKEUP_CLOCK_DATA,
+        WAKEUP_SIGNAL_DATA,
+        WAKEUP_INOTIFY_DATA,
+        _WAKEUP_TYPE_MAX,
+        _WAKEUP_TYPE_INVALID = -1,
+} WakeupType;
+
+struct inode_data;
+
+struct sd_event_source {
+        WakeupType wakeup;
+
+        unsigned n_ref;
+
+        sd_event *event;
+        void *userdata;
+        sd_event_handler_t prepare;
+
+        char *description;
+
+        EventSourceType type:5;
+        signed int enabled:3;
+        bool pending:1;
+        bool dispatching:1;
+        bool floating:1;
+        bool exit_on_failure:1;
+
+        int64_t priority;
+        unsigned pending_index;
+        unsigned prepare_index;
+        uint64_t pending_iteration;
+        uint64_t prepare_iteration;
+
+        sd_event_destroy_t destroy_callback;
+
+        LIST_FIELDS(sd_event_source, sources);
+
+        union {
+                struct {
+                        sd_event_io_handler_t callback;
+                        int fd;
+                        uint32_t events;
+                        uint32_t revents;
+                        bool registered:1;
+                        bool owned:1;
+                } io;
+                struct {
+                        sd_event_time_handler_t callback;
+                        usec_t next, accuracy;
+                        unsigned earliest_index;
+                        unsigned latest_index;
+                } time;
+                struct {
+                        sd_event_signal_handler_t callback;
+                        struct signalfd_siginfo siginfo;
+                        int sig;
+                } signal;
+                struct {
+                        sd_event_child_handler_t callback;
+                        siginfo_t siginfo;
+                        pid_t pid;
+                        int options;
+                        int pidfd;
+                        bool registered:1; /* whether the pidfd is registered in the epoll */
+                        bool pidfd_owned:1; /* close pidfd when event source is freed */
+                        bool process_owned:1; /* kill+reap process when event source is freed */
+                        bool exited:1; /* true if process exited (i.e. if there's value in SIGKILLing it if we want to get rid of it) */
+                        bool waited:1; /* true if process was waited for (i.e. if there's value in waitid(P_PID)'ing it if we want to get rid of it) */
+                } child;
+                struct {
+                        sd_event_handler_t callback;
+                } defer;
+                struct {
+                        sd_event_handler_t callback;
+                } post;
+                struct {
+                        sd_event_handler_t callback;
+                        unsigned prioq_index;
+                } exit;
+                struct {
+                        sd_event_inotify_handler_t callback;
+                        uint32_t mask;
+                        struct inode_data *inode_data;
+                        LIST_FIELDS(sd_event_source, by_inode_data);
+                } inotify;
+        };
+};
+
+struct clock_data {
+        WakeupType wakeup;
+        int fd;
+
+        /* For all clocks we maintain two priority queues each, one
+         * ordered for the earliest times the events may be
+         * dispatched, and one ordered by the latest times they must
+         * have been dispatched. The range between the top entries in
+         * the two prioqs is the time window we can freely schedule
+         * wakeups in */
+
+        Prioq *earliest;
+        Prioq *latest;
+        usec_t next;
+
+        bool needs_rearm:1;
+};
+
+struct signal_data {
+        WakeupType wakeup;
+
+        /* For each priority we maintain one signal fd, so that we
+         * only have to dequeue a single event per priority at a
+         * time. */
+
+        int fd;
+        int64_t priority;
+        sigset_t sigset;
+        sd_event_source *current;
+};
+
+/* A structure listing all event sources currently watching a specific inode */
+struct inode_data {
+        /* The identifier for the inode, the combination of the .st_dev + .st_ino fields of the file */
+        ino_t ino;
+        dev_t dev;
+
+        /* An fd of the inode to watch. The fd is kept open until the next iteration of the loop, so that we can
+         * rearrange the priority still until then, as we need the original inode to change the priority as we need to
+         * add a watch descriptor to the right inotify for the priority which we can only do if we have a handle to the
+         * original inode. We keep a list of all inode_data objects with an open fd in the to_close list (see below) of
+         * the sd-event object, so that it is efficient to close everything, before entering the next event loop
+         * iteration. */
+        int fd;
+
+        /* The inotify "watch descriptor" */
+        int wd;
+
+        /* The combination of the mask of all inotify watches on this inode we manage. This is also the mask that has
+         * most recently been set on the watch descriptor. */
+        uint32_t combined_mask;
+
+        /* All event sources subscribed to this inode */
+        LIST_HEAD(sd_event_source, event_sources);
+
+        /* The inotify object we watch this inode with */
+        struct inotify_data *inotify_data;
+
+        /* A linked list of all inode data objects with fds to close (see above) */
+        LIST_FIELDS(struct inode_data, to_close);
+};
+
+/* A structure encapsulating an inotify fd */
+struct inotify_data {
+        WakeupType wakeup;
+
+        /* For each priority we maintain one inotify fd, so that we only have to dequeue a single event per priority at
+         * a time */
+
+        int fd;
+        int64_t priority;
+
+        Hashmap *inodes; /* The inode_data structures keyed by dev+ino */
+        Hashmap *wd;     /* The inode_data structures keyed by the watch descriptor for each */
+
+        /* The buffer we read inotify events into */
+        union inotify_event_buffer buffer;
+        size_t buffer_filled; /* fill level of the buffer */
+
+        /* How many event sources are currently marked pending for this inotify. We won't read new events off the
+         * inotify fd as long as there are still pending events on the inotify (because we have no strategy of queuing
+         * the events locally if they can't be coalesced). */
+        unsigned n_pending;
+
+        /* A linked list of all inotify objects with data already read, that still need processing. We keep this list
+         * to make it efficient to figure out what inotify objects to process data on next. */
+        LIST_FIELDS(struct inotify_data, buffered);
+};
diff --git a/src/libsystemd/sd-event/event-util.c b/src/libsystemd/sd-event/event-util.c
new file mode 100644
index 0000000..132796f
--- /dev/null
+++ b/src/libsystemd/sd-event/event-util.c
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+
+#include "event-source.h"
+#include "event-util.h"
+#include "log.h"
+#include "string-util.h"
+
+int event_reset_time(
+                sd_event *e,
+                sd_event_source **s,
+                clockid_t clock,
+                uint64_t usec,
+                uint64_t accuracy,
+                sd_event_time_handler_t callback,
+                void *userdata,
+                int64_t priority,
+                const char *description,
+                bool force_reset) {
+
+        bool created = false;
+        int enabled, r;
+        clockid_t c;
+
+        assert(e);
+        assert(s);
+
+        if (*s) {
+                if (!force_reset) {
+                        r = sd_event_source_get_enabled(*s, &enabled);
+                        if (r < 0)
+                                return log_debug_errno(r, "sd-event: Failed to query whether event source \"%s\" is enabled or not: %m",
+                                                       strna((*s)->description ?: description));
+
+                        if (enabled != SD_EVENT_OFF)
+                                return 0;
+                }
+
+                r = sd_event_source_get_time_clock(*s, &c);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-event: Failed to get clock id of event source \"%s\": %m", strna((*s)->description ?: description));
+
+                if (c != clock)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "sd-event: Current clock id %i of event source \"%s\" is different from specified one %i.",
+                                               (int)c,
+                                               strna((*s)->description ? : description),
+                                               (int)clock);
+
+                r = sd_event_source_set_time(*s, usec);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-event: Failed to set time for event source \"%s\": %m", strna((*s)->description ?: description));
+
+                r = sd_event_source_set_time_accuracy(*s, accuracy);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-event: Failed to set accuracy for event source \"%s\": %m", strna((*s)->description ?: description));
+
+                /* callback function is not updated, as we do not have sd_event_source_set_time_callback(). */
+
+                (void) sd_event_source_set_userdata(*s, userdata);
+
+                r = sd_event_source_set_enabled(*s, SD_EVENT_ONESHOT);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-event: Failed to enable event source \"%s\": %m", strna((*s)->description ?: description));
+        } else {
+                r = sd_event_add_time(e, s, clock, usec, accuracy, callback, userdata);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-event: Failed to create timer event \"%s\": %m", strna(description));
+
+                created = true;
+        }
+
+        r = sd_event_source_set_priority(*s, priority);
+        if (r < 0)
+                return log_debug_errno(r, "sd-event: Failed to set priority for event source \"%s\": %m", strna((*s)->description ?: description));
+
+        if (description) {
+                r = sd_event_source_set_description(*s, description);
+                if (r < 0)
+                        return log_debug_errno(r, "sd-event: Failed to set description for event source \"%s\": %m", description);
+        }
+
+        return created;
+}
+
+int event_source_disable(sd_event_source *s) {
+        if (!s)
+                return 0;
+
+        return sd_event_source_set_enabled(s, SD_EVENT_OFF);
+}
+
+int event_source_is_enabled(sd_event_source *s) {
+        if (!s)
+                return false;
+
+        return sd_event_source_get_enabled(s, NULL);
+}
diff --git a/src/libsystemd/sd-event/event-util.h b/src/libsystemd/sd-event/event-util.h
new file mode 100644
index 0000000..c8f97bc
--- /dev/null
+++ b/src/libsystemd/sd-event/event-util.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+#include "sd-event.h"
+
+int event_reset_time(sd_event *e, sd_event_source **s,
+                     clockid_t clock, uint64_t usec, uint64_t accuracy,
+                     sd_event_time_handler_t callback, void *userdata,
+                     int64_t priority, const char *description, bool force_reset);
+int event_source_disable(sd_event_source *s);
+int event_source_is_enabled(sd_event_source *s);
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
new file mode 100644
index 0000000..789a8c7
--- /dev/null
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -0,0 +1,4010 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <sys/wait.h>
+
+#include "sd-daemon.h"
+#include "sd-event.h"
+#include "sd-id128.h"
+
+#include "alloc-util.h"
+#include "env-util.h"
+#include "event-source.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "hashmap.h"
+#include "list.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "missing_syscall.h"
+#include "prioq.h"
+#include "process-util.h"
+#include "set.h"
+#include "signal-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "strxcpyx.h"
+#include "time-util.h"
+
+#define DEFAULT_ACCURACY_USEC (250 * USEC_PER_MSEC)
+
+static bool EVENT_SOURCE_WATCH_PIDFD(sd_event_source *s) {
+        /* Returns true if this is a PID event source and can be implemented by watching EPOLLIN */
+        return s &&
+                s->type == SOURCE_CHILD &&
+                s->child.pidfd >= 0 &&
+                s->child.options == WEXITED;
+}
+
+static const char* const event_source_type_table[_SOURCE_EVENT_SOURCE_TYPE_MAX] = {
+        [SOURCE_IO] = "io",
+        [SOURCE_TIME_REALTIME] = "realtime",
+        [SOURCE_TIME_BOOTTIME] = "bootime",
+        [SOURCE_TIME_MONOTONIC] = "monotonic",
+        [SOURCE_TIME_REALTIME_ALARM] = "realtime-alarm",
+        [SOURCE_TIME_BOOTTIME_ALARM] = "boottime-alarm",
+        [SOURCE_SIGNAL] = "signal",
+        [SOURCE_CHILD] = "child",
+        [SOURCE_DEFER] = "defer",
+        [SOURCE_POST] = "post",
+        [SOURCE_EXIT] = "exit",
+        [SOURCE_WATCHDOG] = "watchdog",
+        [SOURCE_INOTIFY] = "inotify",
+};
+
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(event_source_type, int);
+
+#define EVENT_SOURCE_IS_TIME(t) IN_SET((t), SOURCE_TIME_REALTIME, SOURCE_TIME_BOOTTIME, SOURCE_TIME_MONOTONIC, SOURCE_TIME_REALTIME_ALARM, SOURCE_TIME_BOOTTIME_ALARM)
+
+struct sd_event {
+        unsigned n_ref;
+
+        int epoll_fd;
+        int watchdog_fd;
+
+        Prioq *pending;
+        Prioq *prepare;
+
+        /* timerfd_create() only supports these five clocks so far. We
+         * can add support for more clocks when the kernel learns to
+         * deal with them, too. */
+        struct clock_data realtime;
+        struct clock_data boottime;
+        struct clock_data monotonic;
+        struct clock_data realtime_alarm;
+        struct clock_data boottime_alarm;
+
+        usec_t perturb;
+
+        sd_event_source **signal_sources; /* indexed by signal number */
+        Hashmap *signal_data; /* indexed by priority */
+
+        Hashmap *child_sources;
+        unsigned n_enabled_child_sources;
+
+        Set *post_sources;
+
+        Prioq *exit;
+
+        Hashmap *inotify_data; /* indexed by priority */
+
+        /* A list of inode structures that still have an fd open, that we need to close before the next loop iteration */
+        LIST_HEAD(struct inode_data, inode_data_to_close);
+
+        /* A list of inotify objects that already have events buffered which aren't processed yet */
+        LIST_HEAD(struct inotify_data, inotify_data_buffered);
+
+        pid_t original_pid;
+
+        uint64_t iteration;
+        triple_timestamp timestamp;
+        int state;
+
+        bool exit_requested:1;
+        bool need_process_child:1;
+        bool watchdog:1;
+        bool profile_delays:1;
+
+        int exit_code;
+
+        pid_t tid;
+        sd_event **default_event_ptr;
+
+        usec_t watchdog_last, watchdog_period;
+
+        unsigned n_sources;
+
+        struct epoll_event *event_queue;
+        size_t event_queue_allocated;
+
+        LIST_HEAD(sd_event_source, sources);
+
+        usec_t last_run, last_log;
+        unsigned delays[sizeof(usec_t) * 8];
+};
+
+static thread_local sd_event *default_event = NULL;
+
+static void source_disconnect(sd_event_source *s);
+static void event_gc_inode_data(sd_event *e, struct inode_data *d);
+
+static sd_event *event_resolve(sd_event *e) {
+        return e == SD_EVENT_DEFAULT ? default_event : e;
+}
+
+static int pending_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+        int r;
+
+        assert(x->pending);
+        assert(y->pending);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Lower priority values first */
+        r = CMP(x->priority, y->priority);
+        if (r != 0)
+                return r;
+
+        /* Older entries first */
+        return CMP(x->pending_iteration, y->pending_iteration);
+}
+
+static int prepare_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+        int r;
+
+        assert(x->prepare);
+        assert(y->prepare);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Move most recently prepared ones last, so that we can stop
+         * preparing as soon as we hit one that has already been
+         * prepared in the current iteration */
+        r = CMP(x->prepare_iteration, y->prepare_iteration);
+        if (r != 0)
+                return r;
+
+        /* Lower priority values first */
+        return CMP(x->priority, y->priority);
+}
+
+static int earliest_time_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(EVENT_SOURCE_IS_TIME(x->type));
+        assert(x->type == y->type);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Move the pending ones to the end */
+        if (!x->pending && y->pending)
+                return -1;
+        if (x->pending && !y->pending)
+                return 1;
+
+        /* Order by time */
+        return CMP(x->time.next, y->time.next);
+}
+
+static usec_t time_event_source_latest(const sd_event_source *s) {
+        return usec_add(s->time.next, s->time.accuracy);
+}
+
+static int latest_time_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(EVENT_SOURCE_IS_TIME(x->type));
+        assert(x->type == y->type);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Move the pending ones to the end */
+        if (!x->pending && y->pending)
+                return -1;
+        if (x->pending && !y->pending)
+                return 1;
+
+        /* Order by time */
+        return CMP(time_event_source_latest(x), time_event_source_latest(y));
+}
+
+static int exit_prioq_compare(const void *a, const void *b) {
+        const sd_event_source *x = a, *y = b;
+
+        assert(x->type == SOURCE_EXIT);
+        assert(y->type == SOURCE_EXIT);
+
+        /* Enabled ones first */
+        if (x->enabled != SD_EVENT_OFF && y->enabled == SD_EVENT_OFF)
+                return -1;
+        if (x->enabled == SD_EVENT_OFF && y->enabled != SD_EVENT_OFF)
+                return 1;
+
+        /* Lower priority values first */
+        return CMP(x->priority, y->priority);
+}
+
+static void free_clock_data(struct clock_data *d) {
+        assert(d);
+        assert(d->wakeup == WAKEUP_CLOCK_DATA);
+
+        safe_close(d->fd);
+        prioq_free(d->earliest);
+        prioq_free(d->latest);
+}
+
+static sd_event *event_free(sd_event *e) {
+        sd_event_source *s;
+
+        assert(e);
+
+        while ((s = e->sources)) {
+                assert(s->floating);
+                source_disconnect(s);
+                sd_event_source_unref(s);
+        }
+
+        assert(e->n_sources == 0);
+
+        if (e->default_event_ptr)
+                *(e->default_event_ptr) = NULL;
+
+        safe_close(e->epoll_fd);
+        safe_close(e->watchdog_fd);
+
+        free_clock_data(&e->realtime);
+        free_clock_data(&e->boottime);
+        free_clock_data(&e->monotonic);
+        free_clock_data(&e->realtime_alarm);
+        free_clock_data(&e->boottime_alarm);
+
+        prioq_free(e->pending);
+        prioq_free(e->prepare);
+        prioq_free(e->exit);
+
+        free(e->signal_sources);
+        hashmap_free(e->signal_data);
+
+        hashmap_free(e->inotify_data);
+
+        hashmap_free(e->child_sources);
+        set_free(e->post_sources);
+
+        free(e->event_queue);
+
+        return mfree(e);
+}
+
+_public_ int sd_event_new(sd_event** ret) {
+        sd_event *e;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        e = new(sd_event, 1);
+        if (!e)
+                return -ENOMEM;
+
+        *e = (sd_event) {
+                .n_ref = 1,
+                .epoll_fd = -1,
+                .watchdog_fd = -1,
+                .realtime.wakeup = WAKEUP_CLOCK_DATA,
+                .realtime.fd = -1,
+                .realtime.next = USEC_INFINITY,
+                .boottime.wakeup = WAKEUP_CLOCK_DATA,
+                .boottime.fd = -1,
+                .boottime.next = USEC_INFINITY,
+                .monotonic.wakeup = WAKEUP_CLOCK_DATA,
+                .monotonic.fd = -1,
+                .monotonic.next = USEC_INFINITY,
+                .realtime_alarm.wakeup = WAKEUP_CLOCK_DATA,
+                .realtime_alarm.fd = -1,
+                .realtime_alarm.next = USEC_INFINITY,
+                .boottime_alarm.wakeup = WAKEUP_CLOCK_DATA,
+                .boottime_alarm.fd = -1,
+                .boottime_alarm.next = USEC_INFINITY,
+                .perturb = USEC_INFINITY,
+                .original_pid = getpid_cached(),
+        };
+
+        r = prioq_ensure_allocated(&e->pending, pending_prioq_compare);
+        if (r < 0)
+                goto fail;
+
+        e->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+        if (e->epoll_fd < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        e->epoll_fd = fd_move_above_stdio(e->epoll_fd);
+
+        if (secure_getenv("SD_EVENT_PROFILE_DELAYS")) {
+                log_debug("Event loop profiling enabled. Logarithmic histogram of event loop iterations in the range 2^0 ... 2^63 us will be logged every 5s.");
+                e->profile_delays = true;
+        }
+
+        *ret = e;
+        return 0;
+
+fail:
+        event_free(e);
+        return r;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_event, sd_event, event_free);
+
+_public_ sd_event_source* sd_event_source_disable_unref(sd_event_source *s) {
+        if (s)
+                (void) sd_event_source_set_enabled(s, SD_EVENT_OFF);
+        return sd_event_source_unref(s);
+}
+
+static bool event_pid_changed(sd_event *e) {
+        assert(e);
+
+        /* We don't support people creating an event loop and keeping
+         * it around over a fork(). Let's complain. */
+
+        return e->original_pid != getpid_cached();
+}
+
+static void source_io_unregister(sd_event_source *s) {
+        assert(s);
+        assert(s->type == SOURCE_IO);
+
+        if (event_pid_changed(s->event))
+                return;
+
+        if (!s->io.registered)
+                return;
+
+        if (epoll_ctl(s->event->epoll_fd, EPOLL_CTL_DEL, s->io.fd, NULL) < 0)
+                log_debug_errno(errno, "Failed to remove source %s (type %s) from epoll: %m",
+                                strna(s->description), event_source_type_to_string(s->type));
+
+        s->io.registered = false;
+}
+
+static int source_io_register(
+                sd_event_source *s,
+                int enabled,
+                uint32_t events) {
+
+        assert(s);
+        assert(s->type == SOURCE_IO);
+        assert(enabled != SD_EVENT_OFF);
+
+        struct epoll_event ev = {
+                .events = events | (enabled == SD_EVENT_ONESHOT ? EPOLLONESHOT : 0),
+                .data.ptr = s,
+        };
+
+        if (epoll_ctl(s->event->epoll_fd,
+                      s->io.registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD,
+                      s->io.fd, &ev) < 0)
+                return -errno;
+
+        s->io.registered = true;
+
+        return 0;
+}
+
+static void source_child_pidfd_unregister(sd_event_source *s) {
+        assert(s);
+        assert(s->type == SOURCE_CHILD);
+
+        if (event_pid_changed(s->event))
+                return;
+
+        if (!s->child.registered)
+                return;
+
+        if (EVENT_SOURCE_WATCH_PIDFD(s))
+                if (epoll_ctl(s->event->epoll_fd, EPOLL_CTL_DEL, s->child.pidfd, NULL) < 0)
+                        log_debug_errno(errno, "Failed to remove source %s (type %s) from epoll: %m",
+                                        strna(s->description), event_source_type_to_string(s->type));
+
+        s->child.registered = false;
+}
+
+static int source_child_pidfd_register(sd_event_source *s, int enabled) {
+        assert(s);
+        assert(s->type == SOURCE_CHILD);
+        assert(enabled != SD_EVENT_OFF);
+
+        if (EVENT_SOURCE_WATCH_PIDFD(s)) {
+                struct epoll_event ev = {
+                        .events = EPOLLIN | (enabled == SD_EVENT_ONESHOT ? EPOLLONESHOT : 0),
+                        .data.ptr = s,
+                };
+
+                if (epoll_ctl(s->event->epoll_fd,
+                              s->child.registered ? EPOLL_CTL_MOD : EPOLL_CTL_ADD,
+                              s->child.pidfd, &ev) < 0)
+                        return -errno;
+        }
+
+        s->child.registered = true;
+        return 0;
+}
+
+static clockid_t event_source_type_to_clock(EventSourceType t) {
+
+        switch (t) {
+
+        case SOURCE_TIME_REALTIME:
+                return CLOCK_REALTIME;
+
+        case SOURCE_TIME_BOOTTIME:
+                return CLOCK_BOOTTIME;
+
+        case SOURCE_TIME_MONOTONIC:
+                return CLOCK_MONOTONIC;
+
+        case SOURCE_TIME_REALTIME_ALARM:
+                return CLOCK_REALTIME_ALARM;
+
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                return CLOCK_BOOTTIME_ALARM;
+
+        default:
+                return (clockid_t) -1;
+        }
+}
+
+static EventSourceType clock_to_event_source_type(clockid_t clock) {
+
+        switch (clock) {
+
+        case CLOCK_REALTIME:
+                return SOURCE_TIME_REALTIME;
+
+        case CLOCK_BOOTTIME:
+                return SOURCE_TIME_BOOTTIME;
+
+        case CLOCK_MONOTONIC:
+                return SOURCE_TIME_MONOTONIC;
+
+        case CLOCK_REALTIME_ALARM:
+                return SOURCE_TIME_REALTIME_ALARM;
+
+        case CLOCK_BOOTTIME_ALARM:
+                return SOURCE_TIME_BOOTTIME_ALARM;
+
+        default:
+                return _SOURCE_EVENT_SOURCE_TYPE_INVALID;
+        }
+}
+
+static struct clock_data* event_get_clock_data(sd_event *e, EventSourceType t) {
+        assert(e);
+
+        switch (t) {
+
+        case SOURCE_TIME_REALTIME:
+                return &e->realtime;
+
+        case SOURCE_TIME_BOOTTIME:
+                return &e->boottime;
+
+        case SOURCE_TIME_MONOTONIC:
+                return &e->monotonic;
+
+        case SOURCE_TIME_REALTIME_ALARM:
+                return &e->realtime_alarm;
+
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                return &e->boottime_alarm;
+
+        default:
+                return NULL;
+        }
+}
+
+static void event_free_signal_data(sd_event *e, struct signal_data *d) {
+        assert(e);
+
+        if (!d)
+                return;
+
+        hashmap_remove(e->signal_data, &d->priority);
+        safe_close(d->fd);
+        free(d);
+}
+
+static int event_make_signal_data(
+                sd_event *e,
+                int sig,
+                struct signal_data **ret) {
+
+        struct signal_data *d;
+        bool added = false;
+        sigset_t ss_copy;
+        int64_t priority;
+        int r;
+
+        assert(e);
+
+        if (event_pid_changed(e))
+                return -ECHILD;
+
+        if (e->signal_sources && e->signal_sources[sig])
+                priority = e->signal_sources[sig]->priority;
+        else
+                priority = SD_EVENT_PRIORITY_NORMAL;
+
+        d = hashmap_get(e->signal_data, &priority);
+        if (d) {
+                if (sigismember(&d->sigset, sig) > 0) {
+                        if (ret)
+                                *ret = d;
+                        return 0;
+                }
+        } else {
+                r = hashmap_ensure_allocated(&e->signal_data, &uint64_hash_ops);
+                if (r < 0)
+                        return r;
+
+                d = new(struct signal_data, 1);
+                if (!d)
+                        return -ENOMEM;
+
+                *d = (struct signal_data) {
+                        .wakeup = WAKEUP_SIGNAL_DATA,
+                        .fd = -1,
+                        .priority = priority,
+                };
+
+                r = hashmap_put(e->signal_data, &d->priority, d);
+                if (r < 0) {
+                        free(d);
+                        return r;
+                }
+
+                added = true;
+        }
+
+        ss_copy = d->sigset;
+        assert_se(sigaddset(&ss_copy, sig) >= 0);
+
+        r = signalfd(d->fd, &ss_copy, SFD_NONBLOCK|SFD_CLOEXEC);
+        if (r < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        d->sigset = ss_copy;
+
+        if (d->fd >= 0) {
+                if (ret)
+                        *ret = d;
+                return 0;
+        }
+
+        d->fd = fd_move_above_stdio(r);
+
+        struct epoll_event ev = {
+                .events = EPOLLIN,
+                .data.ptr = d,
+        };
+
+        if (epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, d->fd, &ev) < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        if (ret)
+                *ret = d;
+
+        return 0;
+
+fail:
+        if (added)
+                event_free_signal_data(e, d);
+
+        return r;
+}
+
+static void event_unmask_signal_data(sd_event *e, struct signal_data *d, int sig) {
+        assert(e);
+        assert(d);
+
+        /* Turns off the specified signal in the signal data
+         * object. If the signal mask of the object becomes empty that
+         * way removes it. */
+
+        if (sigismember(&d->sigset, sig) == 0)
+                return;
+
+        assert_se(sigdelset(&d->sigset, sig) >= 0);
+
+        if (sigisemptyset(&d->sigset)) {
+                /* If all the mask is all-zero we can get rid of the structure */
+                event_free_signal_data(e, d);
+                return;
+        }
+
+        assert(d->fd >= 0);
+
+        if (signalfd(d->fd, &d->sigset, SFD_NONBLOCK|SFD_CLOEXEC) < 0)
+                log_debug_errno(errno, "Failed to unset signal bit, ignoring: %m");
+}
+
+static void event_gc_signal_data(sd_event *e, const int64_t *priority, int sig) {
+        struct signal_data *d;
+        static const int64_t zero_priority = 0;
+
+        assert(e);
+
+        /* Rechecks if the specified signal is still something we are interested in. If not, we'll unmask it,
+         * and possibly drop the signalfd for it. */
+
+        if (sig == SIGCHLD &&
+            e->n_enabled_child_sources > 0)
+                return;
+
+        if (e->signal_sources &&
+            e->signal_sources[sig] &&
+            e->signal_sources[sig]->enabled != SD_EVENT_OFF)
+                return;
+
+        /*
+         * The specified signal might be enabled in three different queues:
+         *
+         * 1) the one that belongs to the priority passed (if it is non-NULL)
+         * 2) the one that belongs to the priority of the event source of the signal (if there is one)
+         * 3) the 0 priority (to cover the SIGCHLD case)
+         *
+         * Hence, let's remove it from all three here.
+         */
+
+        if (priority) {
+                d = hashmap_get(e->signal_data, priority);
+                if (d)
+                        event_unmask_signal_data(e, d, sig);
+        }
+
+        if (e->signal_sources && e->signal_sources[sig]) {
+                d = hashmap_get(e->signal_data, &e->signal_sources[sig]->priority);
+                if (d)
+                        event_unmask_signal_data(e, d, sig);
+        }
+
+        d = hashmap_get(e->signal_data, &zero_priority);
+        if (d)
+                event_unmask_signal_data(e, d, sig);
+}
+
+static void event_source_pp_prioq_reshuffle(sd_event_source *s) {
+        assert(s);
+
+        /* Reshuffles the pending + prepare prioqs. Called whenever the dispatch order changes, i.e. when
+         * they are enabled/disabled or marked pending and such. */
+
+        if (s->pending)
+                prioq_reshuffle(s->event->pending, s, &s->pending_index);
+
+        if (s->prepare)
+                prioq_reshuffle(s->event->prepare, s, &s->prepare_index);
+}
+
+static void event_source_time_prioq_reshuffle(sd_event_source *s) {
+        struct clock_data *d;
+
+        assert(s);
+        assert(EVENT_SOURCE_IS_TIME(s->type));
+
+        /* Called whenever the event source's timer ordering properties changed, i.e. time, accuracy,
+         * pending, enable state. Makes sure the two prioq's are ordered properly again. */
+        assert_se(d = event_get_clock_data(s->event, s->type));
+        prioq_reshuffle(d->earliest, s, &s->time.earliest_index);
+        prioq_reshuffle(d->latest, s, &s->time.latest_index);
+        d->needs_rearm = true;
+}
+
+static void source_disconnect(sd_event_source *s) {
+        sd_event *event;
+
+        assert(s);
+
+        if (!s->event)
+                return;
+
+        assert(s->event->n_sources > 0);
+
+        switch (s->type) {
+
+        case SOURCE_IO:
+                if (s->io.fd >= 0)
+                        source_io_unregister(s);
+
+                break;
+
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM: {
+                struct clock_data *d;
+
+                d = event_get_clock_data(s->event, s->type);
+                assert(d);
+
+                prioq_remove(d->earliest, s, &s->time.earliest_index);
+                prioq_remove(d->latest, s, &s->time.latest_index);
+                d->needs_rearm = true;
+                break;
+        }
+
+        case SOURCE_SIGNAL:
+                if (s->signal.sig > 0) {
+
+                        if (s->event->signal_sources)
+                                s->event->signal_sources[s->signal.sig] = NULL;
+
+                        event_gc_signal_data(s->event, &s->priority, s->signal.sig);
+                }
+
+                break;
+
+        case SOURCE_CHILD:
+                if (s->child.pid > 0) {
+                        if (s->enabled != SD_EVENT_OFF) {
+                                assert(s->event->n_enabled_child_sources > 0);
+                                s->event->n_enabled_child_sources--;
+                        }
+
+                        (void) hashmap_remove(s->event->child_sources, PID_TO_PTR(s->child.pid));
+                }
+
+                if (EVENT_SOURCE_WATCH_PIDFD(s))
+                        source_child_pidfd_unregister(s);
+                else
+                        event_gc_signal_data(s->event, &s->priority, SIGCHLD);
+
+                break;
+
+        case SOURCE_DEFER:
+                /* nothing */
+                break;
+
+        case SOURCE_POST:
+                set_remove(s->event->post_sources, s);
+                break;
+
+        case SOURCE_EXIT:
+                prioq_remove(s->event->exit, s, &s->exit.prioq_index);
+                break;
+
+        case SOURCE_INOTIFY: {
+                struct inode_data *inode_data;
+
+                inode_data = s->inotify.inode_data;
+                if (inode_data) {
+                        struct inotify_data *inotify_data;
+                        assert_se(inotify_data = inode_data->inotify_data);
+
+                        /* Detach this event source from the inode object */
+                        LIST_REMOVE(inotify.by_inode_data, inode_data->event_sources, s);
+                        s->inotify.inode_data = NULL;
+
+                        if (s->pending) {
+                                assert(inotify_data->n_pending > 0);
+                                inotify_data->n_pending--;
+                        }
+
+                        /* Note that we don't reduce the inotify mask for the watch descriptor here if the inode is
+                         * continued to being watched. That's because inotify doesn't really have an API for that: we
+                         * can only change watch masks with access to the original inode either by fd or by path. But
+                         * paths aren't stable, and keeping an O_PATH fd open all the time would mean wasting an fd
+                         * continuously and keeping the mount busy which we can't really do. We could reconstruct the
+                         * original inode from /proc/self/fdinfo/$INOTIFY_FD (as all watch descriptors are listed
+                         * there), but given the need for open_by_handle_at() which is privileged and not universally
+                         * available this would be quite an incomplete solution. Hence we go the other way, leave the
+                         * mask set, even if it is not minimized now, and ignore all events we aren't interested in
+                         * anymore after reception. Yes, this sucks, but … Linux … */
+
+                        /* Maybe release the inode data (and its inotify) */
+                        event_gc_inode_data(s->event, inode_data);
+                }
+
+                break;
+        }
+
+        default:
+                assert_not_reached("Wut? I shouldn't exist.");
+        }
+
+        if (s->pending)
+                prioq_remove(s->event->pending, s, &s->pending_index);
+
+        if (s->prepare)
+                prioq_remove(s->event->prepare, s, &s->prepare_index);
+
+        event = TAKE_PTR(s->event);
+        LIST_REMOVE(sources, event->sources, s);
+        event->n_sources--;
+
+        /* Note that we don't invalidate the type here, since we still need it in order to close the fd or
+         * pidfd associated with this event source, which we'll do only on source_free(). */
+
+        if (!s->floating)
+                sd_event_unref(event);
+}
+
+static void source_free(sd_event_source *s) {
+        assert(s);
+
+        source_disconnect(s);
+
+        if (s->type == SOURCE_IO && s->io.owned)
+                s->io.fd = safe_close(s->io.fd);
+
+        if (s->type == SOURCE_CHILD) {
+                /* Eventually the kernel will do this automatically for us, but for now let's emulate this (unreliably) in userspace. */
+
+                if (s->child.process_owned) {
+
+                        if (!s->child.exited) {
+                                bool sent = false;
+
+                                if (s->child.pidfd >= 0) {
+                                        if (pidfd_send_signal(s->child.pidfd, SIGKILL, NULL, 0) < 0) {
+                                                if (errno == ESRCH) /* Already dead */
+                                                        sent = true;
+                                                else if (!ERRNO_IS_NOT_SUPPORTED(errno))
+                                                        log_debug_errno(errno, "Failed to kill process " PID_FMT " via pidfd_send_signal(), re-trying via kill(): %m",
+                                                                        s->child.pid);
+                                        } else
+                                                sent = true;
+                                }
+
+                                if (!sent)
+                                        if (kill(s->child.pid, SIGKILL) < 0)
+                                                if (errno != ESRCH) /* Already dead */
+                                                        log_debug_errno(errno, "Failed to kill process " PID_FMT " via kill(), ignoring: %m",
+                                                                        s->child.pid);
+                        }
+
+                        if (!s->child.waited) {
+                                siginfo_t si = {};
+
+                                /* Reap the child if we can */
+                                (void) waitid(P_PID, s->child.pid, &si, WEXITED);
+                        }
+                }
+
+                if (s->child.pidfd_owned)
+                        s->child.pidfd = safe_close(s->child.pidfd);
+        }
+
+        if (s->destroy_callback)
+                s->destroy_callback(s->userdata);
+
+        free(s->description);
+        free(s);
+}
+DEFINE_TRIVIAL_CLEANUP_FUNC(sd_event_source*, source_free);
+
+static int source_set_pending(sd_event_source *s, bool b) {
+        int r;
+
+        assert(s);
+        assert(s->type != SOURCE_EXIT);
+
+        if (s->pending == b)
+                return 0;
+
+        s->pending = b;
+
+        if (b) {
+                s->pending_iteration = s->event->iteration;
+
+                r = prioq_put(s->event->pending, s, &s->pending_index);
+                if (r < 0) {
+                        s->pending = false;
+                        return r;
+                }
+        } else
+                assert_se(prioq_remove(s->event->pending, s, &s->pending_index));
+
+        if (EVENT_SOURCE_IS_TIME(s->type))
+                event_source_time_prioq_reshuffle(s);
+
+        if (s->type == SOURCE_SIGNAL && !b) {
+                struct signal_data *d;
+
+                d = hashmap_get(s->event->signal_data, &s->priority);
+                if (d && d->current == s)
+                        d->current = NULL;
+        }
+
+        if (s->type == SOURCE_INOTIFY) {
+
+                assert(s->inotify.inode_data);
+                assert(s->inotify.inode_data->inotify_data);
+
+                if (b)
+                        s->inotify.inode_data->inotify_data->n_pending ++;
+                else {
+                        assert(s->inotify.inode_data->inotify_data->n_pending > 0);
+                        s->inotify.inode_data->inotify_data->n_pending --;
+                }
+        }
+
+        return 0;
+}
+
+static sd_event_source *source_new(sd_event *e, bool floating, EventSourceType type) {
+        sd_event_source *s;
+
+        assert(e);
+
+        s = new(sd_event_source, 1);
+        if (!s)
+                return NULL;
+
+        *s = (struct sd_event_source) {
+                .n_ref = 1,
+                .event = e,
+                .floating = floating,
+                .type = type,
+                .pending_index = PRIOQ_IDX_NULL,
+                .prepare_index = PRIOQ_IDX_NULL,
+        };
+
+        if (!floating)
+                sd_event_ref(e);
+
+        LIST_PREPEND(sources, e->sources, s);
+        e->n_sources++;
+
+        return s;
+}
+
+static int io_exit_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_io(
+                sd_event *e,
+                sd_event_source **ret,
+                int fd,
+                uint32_t events,
+                sd_event_io_handler_t callback,
+                void *userdata) {
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(fd >= 0, -EBADF);
+        assert_return(!(events & ~(EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLPRI|EPOLLERR|EPOLLHUP|EPOLLET)), -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = io_exit_callback;
+
+        s = source_new(e, !ret, SOURCE_IO);
+        if (!s)
+                return -ENOMEM;
+
+        s->wakeup = WAKEUP_EVENT_SOURCE;
+        s->io.fd = fd;
+        s->io.events = events;
+        s->io.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ON;
+
+        r = source_io_register(s, s->enabled, events);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+static void initialize_perturb(sd_event *e) {
+        sd_id128_t bootid = {};
+
+        /* When we sleep for longer, we try to realign the wakeup to
+           the same time within each minute/second/250ms, so that
+           events all across the system can be coalesced into a single
+           CPU wakeup. However, let's take some system-specific
+           randomness for this value, so that in a network of systems
+           with synced clocks timer events are distributed a
+           bit. Here, we calculate a perturbation usec offset from the
+           boot ID. */
+
+        if (_likely_(e->perturb != USEC_INFINITY))
+                return;
+
+        if (sd_id128_get_boot(&bootid) >= 0)
+                e->perturb = (bootid.qwords[0] ^ bootid.qwords[1]) % USEC_PER_MINUTE;
+}
+
+static int event_setup_timer_fd(
+                sd_event *e,
+                struct clock_data *d,
+                clockid_t clock) {
+
+        assert(e);
+        assert(d);
+
+        if (_likely_(d->fd >= 0))
+                return 0;
+
+        _cleanup_close_ int fd = -1;
+
+        fd = timerfd_create(clock, TFD_NONBLOCK|TFD_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        fd = fd_move_above_stdio(fd);
+
+        struct epoll_event ev = {
+                .events = EPOLLIN,
+                .data.ptr = d,
+        };
+
+        if (epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0)
+                return -errno;
+
+        d->fd = TAKE_FD(fd);
+        return 0;
+}
+
+static int time_exit_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_time(
+                sd_event *e,
+                sd_event_source **ret,
+                clockid_t clock,
+                uint64_t usec,
+                uint64_t accuracy,
+                sd_event_time_handler_t callback,
+                void *userdata) {
+
+        EventSourceType type;
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        struct clock_data *d;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(accuracy != (uint64_t) -1, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!clock_supported(clock)) /* Checks whether the kernel supports the clock */
+                return -EOPNOTSUPP;
+
+        type = clock_to_event_source_type(clock); /* checks whether sd-event supports this clock */
+        if (type < 0)
+                return -EOPNOTSUPP;
+
+        if (!callback)
+                callback = time_exit_callback;
+
+        d = event_get_clock_data(e, type);
+        assert(d);
+
+        r = prioq_ensure_allocated(&d->earliest, earliest_time_prioq_compare);
+        if (r < 0)
+                return r;
+
+        r = prioq_ensure_allocated(&d->latest, latest_time_prioq_compare);
+        if (r < 0)
+                return r;
+
+        if (d->fd < 0) {
+                r = event_setup_timer_fd(e, d, clock);
+                if (r < 0)
+                        return r;
+        }
+
+        s = source_new(e, !ret, type);
+        if (!s)
+                return -ENOMEM;
+
+        s->time.next = usec;
+        s->time.accuracy = accuracy == 0 ? DEFAULT_ACCURACY_USEC : accuracy;
+        s->time.callback = callback;
+        s->time.earliest_index = s->time.latest_index = PRIOQ_IDX_NULL;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        d->needs_rearm = true;
+
+        r = prioq_put(d->earliest, s, &s->time.earliest_index);
+        if (r < 0)
+                return r;
+
+        r = prioq_put(d->latest, s, &s->time.latest_index);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+_public_ int sd_event_add_time_relative(
+                sd_event *e,
+                sd_event_source **ret,
+                clockid_t clock,
+                uint64_t usec,
+                uint64_t accuracy,
+                sd_event_time_handler_t callback,
+                void *userdata) {
+
+        usec_t t;
+        int r;
+
+        /* Same as sd_event_add_time() but operates relative to the event loop's current point in time, and
+         * checks for overflow. */
+
+        r = sd_event_now(e, clock, &t);
+        if (r < 0)
+                return r;
+
+        if (usec >= USEC_INFINITY - t)
+                return -EOVERFLOW;
+
+        return sd_event_add_time(e, ret, clock, t + usec, accuracy, callback, userdata);
+}
+
+static int signal_exit_callback(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_signal(
+                sd_event *e,
+                sd_event_source **ret,
+                int sig,
+                sd_event_signal_handler_t callback,
+                void *userdata) {
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        struct signal_data *d;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(SIGNAL_VALID(sig), -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = signal_exit_callback;
+
+        r = signal_is_blocked(sig);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EBUSY;
+
+        if (!e->signal_sources) {
+                e->signal_sources = new0(sd_event_source*, _NSIG);
+                if (!e->signal_sources)
+                        return -ENOMEM;
+        } else if (e->signal_sources[sig])
+                return -EBUSY;
+
+        s = source_new(e, !ret, SOURCE_SIGNAL);
+        if (!s)
+                return -ENOMEM;
+
+        s->signal.sig = sig;
+        s->signal.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ON;
+
+        e->signal_sources[sig] = s;
+
+        r = event_make_signal_data(e, sig, &d);
+        if (r < 0)
+                return r;
+
+        /* Use the signal name as description for the event source by default */
+        (void) sd_event_source_set_description(s, signal_to_string(sig));
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+static int child_exit_callback(sd_event_source *s, const siginfo_t *si, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+static bool shall_use_pidfd(void) {
+        /* Mostly relevant for debugging, i.e. this is used in test-event.c to test the event loop once with and once without pidfd */
+        return getenv_bool_secure("SYSTEMD_PIDFD") != 0;
+}
+
+_public_ int sd_event_add_child(
+                sd_event *e,
+                sd_event_source **ret,
+                pid_t pid,
+                int options,
+                sd_event_child_handler_t callback,
+                void *userdata) {
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(pid > 1, -EINVAL);
+        assert_return(!(options & ~(WEXITED|WSTOPPED|WCONTINUED)), -EINVAL);
+        assert_return(options != 0, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = child_exit_callback;
+
+        if (e->n_enabled_child_sources == 0) {
+                /* Caller must block SIGCHLD before using us to watch children, even if pidfd is available,
+                 * for compatibility with pre-pidfd and because we don't want the reap the child processes
+                 * ourselves, i.e. call waitid(), and don't want Linux' default internal logic for that to
+                 * take effect.
+                 *
+                 * (As an optimization we only do this check on the first child event source created.) */
+                r = signal_is_blocked(SIGCHLD);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -EBUSY;
+        }
+
+        r = hashmap_ensure_allocated(&e->child_sources, NULL);
+        if (r < 0)
+                return r;
+
+        if (hashmap_contains(e->child_sources, PID_TO_PTR(pid)))
+                return -EBUSY;
+
+        s = source_new(e, !ret, SOURCE_CHILD);
+        if (!s)
+                return -ENOMEM;
+
+        s->wakeup = WAKEUP_EVENT_SOURCE;
+        s->child.pid = pid;
+        s->child.options = options;
+        s->child.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        /* We always take a pidfd here if we can, even if we wait for anything else than WEXITED, so that we
+         * pin the PID, and make regular waitid() handling race-free. */
+
+        if (shall_use_pidfd()) {
+                s->child.pidfd = pidfd_open(s->child.pid, 0);
+                if (s->child.pidfd < 0) {
+                        /* Propagate errors unless the syscall is not supported or blocked */
+                        if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
+                                return -errno;
+                } else
+                        s->child.pidfd_owned = true; /* If we allocate the pidfd we own it by default */
+        } else
+                s->child.pidfd = -1;
+
+        r = hashmap_put(e->child_sources, PID_TO_PTR(pid), s);
+        if (r < 0)
+                return r;
+
+        if (EVENT_SOURCE_WATCH_PIDFD(s)) {
+                /* We have a pidfd and we only want to watch for exit */
+                r = source_child_pidfd_register(s, s->enabled);
+                if (r < 0)
+                        return r;
+
+        } else {
+                /* We have no pidfd or we shall wait for some other event than WEXITED */
+                r = event_make_signal_data(e, SIGCHLD, NULL);
+                if (r < 0)
+                        return r;
+
+                e->need_process_child = true;
+        }
+
+        e->n_enabled_child_sources++;
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+        return 0;
+}
+
+_public_ int sd_event_add_child_pidfd(
+                sd_event *e,
+                sd_event_source **ret,
+                int pidfd,
+                int options,
+                sd_event_child_handler_t callback,
+                void *userdata) {
+
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        pid_t pid;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(pidfd >= 0, -EBADF);
+        assert_return(!(options & ~(WEXITED|WSTOPPED|WCONTINUED)), -EINVAL);
+        assert_return(options != 0, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = child_exit_callback;
+
+        if (e->n_enabled_child_sources == 0) {
+                r = signal_is_blocked(SIGCHLD);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -EBUSY;
+        }
+
+        r = hashmap_ensure_allocated(&e->child_sources, NULL);
+        if (r < 0)
+                return r;
+
+        r = pidfd_get_pid(pidfd, &pid);
+        if (r < 0)
+                return r;
+
+        if (hashmap_contains(e->child_sources, PID_TO_PTR(pid)))
+                return -EBUSY;
+
+        s = source_new(e, !ret, SOURCE_CHILD);
+        if (!s)
+                return -ENOMEM;
+
+        s->wakeup = WAKEUP_EVENT_SOURCE;
+        s->child.pidfd = pidfd;
+        s->child.pid = pid;
+        s->child.options = options;
+        s->child.callback = callback;
+        s->child.pidfd_owned = false; /* If we got the pidfd passed in we don't own it by default (similar to the IO fd case) */
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        r = hashmap_put(e->child_sources, PID_TO_PTR(pid), s);
+        if (r < 0)
+                return r;
+
+        if (EVENT_SOURCE_WATCH_PIDFD(s)) {
+                /* We only want to watch for WEXITED */
+                r = source_child_pidfd_register(s, s->enabled);
+                if (r < 0)
+                        return r;
+        } else {
+                /* We shall wait for some other event than WEXITED */
+                r = event_make_signal_data(e, SIGCHLD, NULL);
+                if (r < 0)
+                        return r;
+
+                e->need_process_child = true;
+        }
+
+        e->n_enabled_child_sources++;
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+        return 0;
+}
+
+static int generic_exit_callback(sd_event_source *s, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_defer(
+                sd_event *e,
+                sd_event_source **ret,
+                sd_event_handler_t callback,
+                void *userdata) {
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = generic_exit_callback;
+
+        s = source_new(e, !ret, SOURCE_DEFER);
+        if (!s)
+                return -ENOMEM;
+
+        s->defer.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        r = source_set_pending(s, true);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+_public_ int sd_event_add_post(
+                sd_event *e,
+                sd_event_source **ret,
+                sd_event_handler_t callback,
+                void *userdata) {
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = generic_exit_callback;
+
+        s = source_new(e, !ret, SOURCE_POST);
+        if (!s)
+                return -ENOMEM;
+
+        s->post.callback = callback;
+        s->userdata = userdata;
+        s->enabled = SD_EVENT_ON;
+
+        r = set_ensure_put(&e->post_sources, NULL, s);
+        if (r < 0)
+                return r;
+        assert(r > 0);
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+_public_ int sd_event_add_exit(
+                sd_event *e,
+                sd_event_source **ret,
+                sd_event_handler_t callback,
+                void *userdata) {
+
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(callback, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        r = prioq_ensure_allocated(&e->exit, exit_prioq_compare);
+        if (r < 0)
+                return r;
+
+        s = source_new(e, !ret, SOURCE_EXIT);
+        if (!s)
+                return -ENOMEM;
+
+        s->exit.callback = callback;
+        s->userdata = userdata;
+        s->exit.prioq_index = PRIOQ_IDX_NULL;
+        s->enabled = SD_EVENT_ONESHOT;
+
+        r = prioq_put(s->event->exit, s, &s->exit.prioq_index);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+static void event_free_inotify_data(sd_event *e, struct inotify_data *d) {
+        assert(e);
+
+        if (!d)
+                return;
+
+        assert(hashmap_isempty(d->inodes));
+        assert(hashmap_isempty(d->wd));
+
+        if (d->buffer_filled > 0)
+                LIST_REMOVE(buffered, e->inotify_data_buffered, d);
+
+        hashmap_free(d->inodes);
+        hashmap_free(d->wd);
+
+        assert_se(hashmap_remove(e->inotify_data, &d->priority) == d);
+
+        if (d->fd >= 0) {
+                if (epoll_ctl(e->epoll_fd, EPOLL_CTL_DEL, d->fd, NULL) < 0)
+                        log_debug_errno(errno, "Failed to remove inotify fd from epoll, ignoring: %m");
+
+                safe_close(d->fd);
+        }
+        free(d);
+}
+
+static int event_make_inotify_data(
+                sd_event *e,
+                int64_t priority,
+                struct inotify_data **ret) {
+
+        _cleanup_close_ int fd = -1;
+        struct inotify_data *d;
+        int r;
+
+        assert(e);
+
+        d = hashmap_get(e->inotify_data, &priority);
+        if (d) {
+                if (ret)
+                        *ret = d;
+                return 0;
+        }
+
+        fd = inotify_init1(IN_NONBLOCK|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        fd = fd_move_above_stdio(fd);
+
+        r = hashmap_ensure_allocated(&e->inotify_data, &uint64_hash_ops);
+        if (r < 0)
+                return r;
+
+        d = new(struct inotify_data, 1);
+        if (!d)
+                return -ENOMEM;
+
+        *d = (struct inotify_data) {
+                .wakeup = WAKEUP_INOTIFY_DATA,
+                .fd = TAKE_FD(fd),
+                .priority = priority,
+        };
+
+        r = hashmap_put(e->inotify_data, &d->priority, d);
+        if (r < 0) {
+                d->fd = safe_close(d->fd);
+                free(d);
+                return r;
+        }
+
+        struct epoll_event ev = {
+                .events = EPOLLIN,
+                .data.ptr = d,
+        };
+
+        if (epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, d->fd, &ev) < 0) {
+                r = -errno;
+                d->fd = safe_close(d->fd); /* let's close this ourselves, as event_free_inotify_data() would otherwise
+                                            * remove the fd from the epoll first, which we don't want as we couldn't
+                                            * add it in the first place. */
+                event_free_inotify_data(e, d);
+                return r;
+        }
+
+        if (ret)
+                *ret = d;
+
+        return 1;
+}
+
+static int inode_data_compare(const struct inode_data *x, const struct inode_data *y) {
+        int r;
+
+        assert(x);
+        assert(y);
+
+        r = CMP(x->dev, y->dev);
+        if (r != 0)
+                return r;
+
+        return CMP(x->ino, y->ino);
+}
+
+static void inode_data_hash_func(const struct inode_data *d, struct siphash *state) {
+        assert(d);
+
+        siphash24_compress(&d->dev, sizeof(d->dev), state);
+        siphash24_compress(&d->ino, sizeof(d->ino), state);
+}
+
+DEFINE_PRIVATE_HASH_OPS(inode_data_hash_ops, struct inode_data, inode_data_hash_func, inode_data_compare);
+
+static void event_free_inode_data(
+                sd_event *e,
+                struct inode_data *d) {
+
+        assert(e);
+
+        if (!d)
+                return;
+
+        assert(!d->event_sources);
+
+        if (d->fd >= 0) {
+                LIST_REMOVE(to_close, e->inode_data_to_close, d);
+                safe_close(d->fd);
+        }
+
+        if (d->inotify_data) {
+
+                if (d->wd >= 0) {
+                        if (d->inotify_data->fd >= 0) {
+                                /* So here's a problem. At the time this runs the watch descriptor might already be
+                                 * invalidated, because an IN_IGNORED event might be queued right the moment we enter
+                                 * the syscall. Hence, whenever we get EINVAL, ignore it entirely, since it's a very
+                                 * likely case to happen. */
+
+                                if (inotify_rm_watch(d->inotify_data->fd, d->wd) < 0 && errno != EINVAL)
+                                        log_debug_errno(errno, "Failed to remove watch descriptor %i from inotify, ignoring: %m", d->wd);
+                        }
+
+                        assert_se(hashmap_remove(d->inotify_data->wd, INT_TO_PTR(d->wd)) == d);
+                }
+
+                assert_se(hashmap_remove(d->inotify_data->inodes, d) == d);
+        }
+
+        free(d);
+}
+
+static void event_gc_inode_data(
+                sd_event *e,
+                struct inode_data *d) {
+
+        struct inotify_data *inotify_data;
+
+        assert(e);
+
+        if (!d)
+                return;
+
+        if (d->event_sources)
+                return;
+
+        inotify_data = d->inotify_data;
+        event_free_inode_data(e, d);
+
+        if (inotify_data && hashmap_isempty(inotify_data->inodes))
+                event_free_inotify_data(e, inotify_data);
+}
+
+static int event_make_inode_data(
+                sd_event *e,
+                struct inotify_data *inotify_data,
+                dev_t dev,
+                ino_t ino,
+                struct inode_data **ret) {
+
+        struct inode_data *d, key;
+        int r;
+
+        assert(e);
+        assert(inotify_data);
+
+        key = (struct inode_data) {
+                .ino = ino,
+                .dev = dev,
+        };
+
+        d = hashmap_get(inotify_data->inodes, &key);
+        if (d) {
+                if (ret)
+                        *ret = d;
+
+                return 0;
+        }
+
+        r = hashmap_ensure_allocated(&inotify_data->inodes, &inode_data_hash_ops);
+        if (r < 0)
+                return r;
+
+        d = new(struct inode_data, 1);
+        if (!d)
+                return -ENOMEM;
+
+        *d = (struct inode_data) {
+                .dev = dev,
+                .ino = ino,
+                .wd = -1,
+                .fd = -1,
+                .inotify_data = inotify_data,
+        };
+
+        r = hashmap_put(inotify_data->inodes, d, d);
+        if (r < 0) {
+                free(d);
+                return r;
+        }
+
+        if (ret)
+                *ret = d;
+
+        return 1;
+}
+
+static uint32_t inode_data_determine_mask(struct inode_data *d) {
+        bool excl_unlink = true;
+        uint32_t combined = 0;
+        sd_event_source *s;
+
+        assert(d);
+
+        /* Combines the watch masks of all event sources watching this inode. We generally just OR them together, but
+         * the IN_EXCL_UNLINK flag is ANDed instead.
+         *
+         * Note that we add all sources to the mask here, regardless whether enabled, disabled or oneshot. That's
+         * because we cannot change the mask anymore after the event source was created once, since the kernel has no
+         * API for that. Hence we need to subscribe to the maximum mask we ever might be interested in, and suppress
+         * events we don't care for client-side. */
+
+        LIST_FOREACH(inotify.by_inode_data, s, d->event_sources) {
+
+                if ((s->inotify.mask & IN_EXCL_UNLINK) == 0)
+                        excl_unlink = false;
+
+                combined |= s->inotify.mask;
+        }
+
+        return (combined & ~(IN_ONESHOT|IN_DONT_FOLLOW|IN_ONLYDIR|IN_EXCL_UNLINK)) | (excl_unlink ? IN_EXCL_UNLINK : 0);
+}
+
+static int inode_data_realize_watch(sd_event *e, struct inode_data *d) {
+        uint32_t combined_mask;
+        int wd, r;
+
+        assert(d);
+        assert(d->fd >= 0);
+
+        combined_mask = inode_data_determine_mask(d);
+
+        if (d->wd >= 0 && combined_mask == d->combined_mask)
+                return 0;
+
+        r = hashmap_ensure_allocated(&d->inotify_data->wd, NULL);
+        if (r < 0)
+                return r;
+
+        wd = inotify_add_watch_fd(d->inotify_data->fd, d->fd, combined_mask);
+        if (wd < 0)
+                return -errno;
+
+        if (d->wd < 0) {
+                r = hashmap_put(d->inotify_data->wd, INT_TO_PTR(wd), d);
+                if (r < 0) {
+                        (void) inotify_rm_watch(d->inotify_data->fd, wd);
+                        return r;
+                }
+
+                d->wd = wd;
+
+        } else if (d->wd != wd) {
+
+                log_debug("Weird, the watch descriptor we already knew for this inode changed?");
+                (void) inotify_rm_watch(d->fd, wd);
+                return -EINVAL;
+        }
+
+        d->combined_mask = combined_mask;
+        return 1;
+}
+
+static int inotify_exit_callback(sd_event_source *s, const struct inotify_event *event, void *userdata) {
+        assert(s);
+
+        return sd_event_exit(sd_event_source_get_event(s), PTR_TO_INT(userdata));
+}
+
+_public_ int sd_event_add_inotify(
+                sd_event *e,
+                sd_event_source **ret,
+                const char *path,
+                uint32_t mask,
+                sd_event_inotify_handler_t callback,
+                void *userdata) {
+
+        struct inotify_data *inotify_data = NULL;
+        struct inode_data *inode_data = NULL;
+        _cleanup_close_ int fd = -1;
+        _cleanup_(source_freep) sd_event_source *s = NULL;
+        struct stat st;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(path, -EINVAL);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!callback)
+                callback = inotify_exit_callback;
+
+        /* Refuse IN_MASK_ADD since we coalesce watches on the same inode, and hence really don't want to merge
+         * masks. Or in other words, this whole code exists only to manage IN_MASK_ADD type operations for you, hence
+         * the user can't use them for us. */
+        if (mask & IN_MASK_ADD)
+                return -EINVAL;
+
+        fd = open(path, O_PATH|O_CLOEXEC|
+                  (mask & IN_ONLYDIR ? O_DIRECTORY : 0)|
+                  (mask & IN_DONT_FOLLOW ? O_NOFOLLOW : 0));
+        if (fd < 0)
+                return -errno;
+
+        if (fstat(fd, &st) < 0)
+                return -errno;
+
+        s = source_new(e, !ret, SOURCE_INOTIFY);
+        if (!s)
+                return -ENOMEM;
+
+        s->enabled = mask & IN_ONESHOT ? SD_EVENT_ONESHOT : SD_EVENT_ON;
+        s->inotify.mask = mask;
+        s->inotify.callback = callback;
+        s->userdata = userdata;
+
+        /* Allocate an inotify object for this priority, and an inode object within it */
+        r = event_make_inotify_data(e, SD_EVENT_PRIORITY_NORMAL, &inotify_data);
+        if (r < 0)
+                return r;
+
+        r = event_make_inode_data(e, inotify_data, st.st_dev, st.st_ino, &inode_data);
+        if (r < 0) {
+                event_free_inotify_data(e, inotify_data);
+                return r;
+        }
+
+        /* Keep the O_PATH fd around until the first iteration of the loop, so that we can still change the priority of
+         * the event source, until then, for which we need the original inode. */
+        if (inode_data->fd < 0) {
+                inode_data->fd = TAKE_FD(fd);
+                LIST_PREPEND(to_close, e->inode_data_to_close, inode_data);
+        }
+
+        /* Link our event source to the inode data object */
+        LIST_PREPEND(inotify.by_inode_data, inode_data->event_sources, s);
+        s->inotify.inode_data = inode_data;
+
+        /* Actually realize the watch now */
+        r = inode_data_realize_watch(e, inode_data);
+        if (r < 0)
+                return r;
+
+        (void) sd_event_source_set_description(s, path);
+
+        if (ret)
+                *ret = s;
+        TAKE_PTR(s);
+
+        return 0;
+}
+
+static sd_event_source* event_source_free(sd_event_source *s) {
+        if (!s)
+                return NULL;
+
+        /* Here's a special hack: when we are called from a
+         * dispatch handler we won't free the event source
+         * immediately, but we will detach the fd from the
+         * epoll. This way it is safe for the caller to unref
+         * the event source and immediately close the fd, but
+         * we still retain a valid event source object after
+         * the callback. */
+
+        if (s->dispatching) {
+                if (s->type == SOURCE_IO)
+                        source_io_unregister(s);
+
+                source_disconnect(s);
+        } else
+                source_free(s);
+
+        return NULL;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_event_source, sd_event_source, event_source_free);
+
+_public_ int sd_event_source_set_description(sd_event_source *s, const char *description) {
+        assert_return(s, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return free_and_strdup(&s->description, description);
+}
+
+_public_ int sd_event_source_get_description(sd_event_source *s, const char **description) {
+        assert_return(s, -EINVAL);
+        assert_return(description, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (!s->description)
+                return -ENXIO;
+
+        *description = s->description;
+        return 0;
+}
+
+_public_ sd_event *sd_event_source_get_event(sd_event_source *s) {
+        assert_return(s, NULL);
+
+        return s->event;
+}
+
+_public_ int sd_event_source_get_pending(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type != SOURCE_EXIT, -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->pending;
+}
+
+_public_ int sd_event_source_get_io_fd(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->io.fd;
+}
+
+_public_ int sd_event_source_set_io_fd(sd_event_source *s, int fd) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(fd >= 0, -EBADF);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (s->io.fd == fd)
+                return 0;
+
+        if (s->enabled == SD_EVENT_OFF) {
+                s->io.fd = fd;
+                s->io.registered = false;
+        } else {
+                int saved_fd;
+
+                saved_fd = s->io.fd;
+                assert(s->io.registered);
+
+                s->io.fd = fd;
+                s->io.registered = false;
+
+                r = source_io_register(s, s->enabled, s->io.events);
+                if (r < 0) {
+                        s->io.fd = saved_fd;
+                        s->io.registered = true;
+                        return r;
+                }
+
+                (void) epoll_ctl(s->event->epoll_fd, EPOLL_CTL_DEL, saved_fd, NULL);
+        }
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_io_fd_own(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+
+        return s->io.owned;
+}
+
+_public_ int sd_event_source_set_io_fd_own(sd_event_source *s, int own) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+
+        s->io.owned = own;
+        return 0;
+}
+
+_public_ int sd_event_source_get_io_events(sd_event_source *s, uint32_t* events) {
+        assert_return(s, -EINVAL);
+        assert_return(events, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *events = s->io.events;
+        return 0;
+}
+
+_public_ int sd_event_source_set_io_events(sd_event_source *s, uint32_t events) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(!(events & ~(EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLPRI|EPOLLERR|EPOLLHUP|EPOLLET)), -EINVAL);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        /* edge-triggered updates are never skipped, so we can reset edges */
+        if (s->io.events == events && !(events & EPOLLET))
+                return 0;
+
+        r = source_set_pending(s, false);
+        if (r < 0)
+                return r;
+
+        if (s->enabled != SD_EVENT_OFF) {
+                r = source_io_register(s, s->enabled, events);
+                if (r < 0)
+                        return r;
+        }
+
+        s->io.events = events;
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_io_revents(sd_event_source *s, uint32_t* revents) {
+        assert_return(s, -EINVAL);
+        assert_return(revents, -EINVAL);
+        assert_return(s->type == SOURCE_IO, -EDOM);
+        assert_return(s->pending, -ENODATA);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *revents = s->io.revents;
+        return 0;
+}
+
+_public_ int sd_event_source_get_signal(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_SIGNAL, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        return s->signal.sig;
+}
+
+_public_ int sd_event_source_get_priority(sd_event_source *s, int64_t *priority) {
+        assert_return(s, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *priority = s->priority;
+        return 0;
+}
+
+_public_ int sd_event_source_set_priority(sd_event_source *s, int64_t priority) {
+        bool rm_inotify = false, rm_inode = false;
+        struct inotify_data *new_inotify_data = NULL;
+        struct inode_data *new_inode_data = NULL;
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (s->priority == priority)
+                return 0;
+
+        if (s->type == SOURCE_INOTIFY) {
+                struct inode_data *old_inode_data;
+
+                assert(s->inotify.inode_data);
+                old_inode_data = s->inotify.inode_data;
+
+                /* We need the original fd to change the priority. If we don't have it we can't change the priority,
+                 * anymore. Note that we close any fds when entering the next event loop iteration, i.e. for inotify
+                 * events we allow priority changes only until the first following iteration. */
+                if (old_inode_data->fd < 0)
+                        return -EOPNOTSUPP;
+
+                r = event_make_inotify_data(s->event, priority, &new_inotify_data);
+                if (r < 0)
+                        return r;
+                rm_inotify = r > 0;
+
+                r = event_make_inode_data(s->event, new_inotify_data, old_inode_data->dev, old_inode_data->ino, &new_inode_data);
+                if (r < 0)
+                        goto fail;
+                rm_inode = r > 0;
+
+                if (new_inode_data->fd < 0) {
+                        /* Duplicate the fd for the new inode object if we don't have any yet */
+                        new_inode_data->fd = fcntl(old_inode_data->fd, F_DUPFD_CLOEXEC, 3);
+                        if (new_inode_data->fd < 0) {
+                                r = -errno;
+                                goto fail;
+                        }
+
+                        LIST_PREPEND(to_close, s->event->inode_data_to_close, new_inode_data);
+                }
+
+                /* Move the event source to the new inode data structure */
+                LIST_REMOVE(inotify.by_inode_data, old_inode_data->event_sources, s);
+                LIST_PREPEND(inotify.by_inode_data, new_inode_data->event_sources, s);
+                s->inotify.inode_data = new_inode_data;
+
+                /* Now create the new watch */
+                r = inode_data_realize_watch(s->event, new_inode_data);
+                if (r < 0) {
+                        /* Move it back */
+                        LIST_REMOVE(inotify.by_inode_data, new_inode_data->event_sources, s);
+                        LIST_PREPEND(inotify.by_inode_data, old_inode_data->event_sources, s);
+                        s->inotify.inode_data = old_inode_data;
+                        goto fail;
+                }
+
+                s->priority = priority;
+
+                event_gc_inode_data(s->event, old_inode_data);
+
+        } else if (s->type == SOURCE_SIGNAL && s->enabled != SD_EVENT_OFF) {
+                struct signal_data *old, *d;
+
+                /* Move us from the signalfd belonging to the old
+                 * priority to the signalfd of the new priority */
+
+                assert_se(old = hashmap_get(s->event->signal_data, &s->priority));
+
+                s->priority = priority;
+
+                r = event_make_signal_data(s->event, s->signal.sig, &d);
+                if (r < 0) {
+                        s->priority = old->priority;
+                        return r;
+                }
+
+                event_unmask_signal_data(s->event, old, s->signal.sig);
+        } else
+                s->priority = priority;
+
+        event_source_pp_prioq_reshuffle(s);
+
+        if (s->type == SOURCE_EXIT)
+                prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+
+        return 0;
+
+fail:
+        if (rm_inode)
+                event_free_inode_data(s->event, new_inode_data);
+
+        if (rm_inotify)
+                event_free_inotify_data(s->event, new_inotify_data);
+
+        return r;
+}
+
+_public_ int sd_event_source_get_enabled(sd_event_source *s, int *m) {
+        assert_return(s, -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (m)
+                *m = s->enabled;
+        return s->enabled != SD_EVENT_OFF;
+}
+
+static int event_source_disable(sd_event_source *s) {
+        int r;
+
+        assert(s);
+        assert(s->enabled != SD_EVENT_OFF);
+
+        /* Unset the pending flag when this event source is disabled */
+        if (!IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) {
+                r = source_set_pending(s, false);
+                if (r < 0)
+                        return r;
+        }
+
+        s->enabled = SD_EVENT_OFF;
+
+        switch (s->type) {
+
+        case SOURCE_IO:
+                source_io_unregister(s);
+                break;
+
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                event_source_time_prioq_reshuffle(s);
+                break;
+
+        case SOURCE_SIGNAL:
+                event_gc_signal_data(s->event, &s->priority, s->signal.sig);
+                break;
+
+        case SOURCE_CHILD:
+                assert(s->event->n_enabled_child_sources > 0);
+                s->event->n_enabled_child_sources--;
+
+                if (EVENT_SOURCE_WATCH_PIDFD(s))
+                        source_child_pidfd_unregister(s);
+                else
+                        event_gc_signal_data(s->event, &s->priority, SIGCHLD);
+                break;
+
+        case SOURCE_EXIT:
+                prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+                break;
+
+        case SOURCE_DEFER:
+        case SOURCE_POST:
+        case SOURCE_INOTIFY:
+                break;
+
+        default:
+                assert_not_reached("Wut? I shouldn't exist.");
+        }
+
+        return 0;
+}
+
+static int event_source_enable(sd_event_source *s, int enable) {
+        int r;
+
+        assert(s);
+        assert(IN_SET(enable, SD_EVENT_ON, SD_EVENT_ONESHOT));
+        assert(s->enabled == SD_EVENT_OFF);
+
+        /* Unset the pending flag when this event source is enabled */
+        if (!IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) {
+                r = source_set_pending(s, false);
+                if (r < 0)
+                        return r;
+        }
+
+        switch (s->type) {
+        case SOURCE_IO:
+                r = source_io_register(s, enable, s->io.events);
+                if (r < 0)
+                        return r;
+                break;
+
+        case SOURCE_SIGNAL:
+                r = event_make_signal_data(s->event, s->signal.sig, NULL);
+                if (r < 0) {
+                        event_gc_signal_data(s->event, &s->priority, s->signal.sig);
+                        return r;
+                }
+
+                break;
+
+        case SOURCE_CHILD:
+                if (EVENT_SOURCE_WATCH_PIDFD(s)) {
+                        /* yes, we have pidfd */
+
+                        r = source_child_pidfd_register(s, enable);
+                        if (r < 0)
+                                return r;
+                } else {
+                        /* no pidfd, or something other to watch for than WEXITED */
+
+                        r = event_make_signal_data(s->event, SIGCHLD, NULL);
+                        if (r < 0) {
+                                event_gc_signal_data(s->event, &s->priority, SIGCHLD);
+                                return r;
+                        }
+                }
+
+                s->event->n_enabled_child_sources++;
+
+                break;
+
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM:
+        case SOURCE_EXIT:
+        case SOURCE_DEFER:
+        case SOURCE_POST:
+        case SOURCE_INOTIFY:
+                break;
+
+        default:
+                assert_not_reached("Wut? I shouldn't exist.");
+        }
+
+        s->enabled = enable;
+
+        /* Non-failing operations below */
+        switch (s->type) {
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                event_source_time_prioq_reshuffle(s);
+                break;
+
+        case SOURCE_EXIT:
+                prioq_reshuffle(s->event->exit, s, &s->exit.prioq_index);
+                break;
+
+        default:
+                break;
+        }
+
+        return 0;
+}
+
+_public_ int sd_event_source_set_enabled(sd_event_source *s, int m) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(IN_SET(m, SD_EVENT_OFF, SD_EVENT_ON, SD_EVENT_ONESHOT), -EINVAL);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        /* If we are dead anyway, we are fine with turning off sources, but everything else needs to fail. */
+        if (s->event->state == SD_EVENT_FINISHED)
+                return m == SD_EVENT_OFF ? 0 : -ESTALE;
+
+        if (s->enabled == m) /* No change? */
+                return 0;
+
+        if (m == SD_EVENT_OFF)
+                r = event_source_disable(s);
+        else {
+                if (s->enabled != SD_EVENT_OFF) {
+                        /* Switching from "on" to "oneshot" or back? If that's the case, we can take a shortcut, the
+                         * event source is already enabled after all. */
+                        s->enabled = m;
+                        return 0;
+                }
+
+                r = event_source_enable(s, m);
+        }
+        if (r < 0)
+                return r;
+
+        event_source_pp_prioq_reshuffle(s);
+        return 0;
+}
+
+_public_ int sd_event_source_get_time(sd_event_source *s, uint64_t *usec) {
+        assert_return(s, -EINVAL);
+        assert_return(usec, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *usec = s->time.next;
+        return 0;
+}
+
+_public_ int sd_event_source_set_time(sd_event_source *s, uint64_t usec) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        r = source_set_pending(s, false);
+        if (r < 0)
+                return r;
+
+        s->time.next = usec;
+
+        event_source_time_prioq_reshuffle(s);
+        return 0;
+}
+
+_public_ int sd_event_source_set_time_relative(sd_event_source *s, uint64_t usec) {
+        usec_t t;
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+
+        r = sd_event_now(s->event, event_source_type_to_clock(s->type), &t);
+        if (r < 0)
+                return r;
+
+        if (usec >= USEC_INFINITY - t)
+                return -EOVERFLOW;
+
+        return sd_event_source_set_time(s, t + usec);
+}
+
+_public_ int sd_event_source_get_time_accuracy(sd_event_source *s, uint64_t *usec) {
+        assert_return(s, -EINVAL);
+        assert_return(usec, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *usec = s->time.accuracy;
+        return 0;
+}
+
+_public_ int sd_event_source_set_time_accuracy(sd_event_source *s, uint64_t usec) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(usec != (uint64_t) -1, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        r = source_set_pending(s, false);
+        if (r < 0)
+                return r;
+
+        if (usec == 0)
+                usec = DEFAULT_ACCURACY_USEC;
+
+        s->time.accuracy = usec;
+
+        event_source_time_prioq_reshuffle(s);
+        return 0;
+}
+
+_public_ int sd_event_source_get_time_clock(sd_event_source *s, clockid_t *clock) {
+        assert_return(s, -EINVAL);
+        assert_return(clock, -EINVAL);
+        assert_return(EVENT_SOURCE_IS_TIME(s->type), -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *clock = event_source_type_to_clock(s->type);
+        return 0;
+}
+
+_public_ int sd_event_source_get_child_pid(sd_event_source *s, pid_t *pid) {
+        assert_return(s, -EINVAL);
+        assert_return(pid, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *pid = s->child.pid;
+        return 0;
+}
+
+_public_ int sd_event_source_get_child_pidfd(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (s->child.pidfd < 0)
+                return -EOPNOTSUPP;
+
+        return s->child.pidfd;
+}
+
+_public_ int sd_event_source_send_child_signal(sd_event_source *s, int sig, const siginfo_t *si, unsigned flags) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+        assert_return(SIGNAL_VALID(sig), -EINVAL);
+
+        /* If we already have seen indication the process exited refuse sending a signal early. This way we
+         * can be sure we don't accidentally kill the wrong process on PID reuse when pidfds are not
+         * available. */
+        if (s->child.exited)
+                return -ESRCH;
+
+        if (s->child.pidfd >= 0) {
+                siginfo_t copy;
+
+                /* pidfd_send_signal() changes the siginfo_t argument. This is weird, let's hence copy the
+                 * structure here */
+                if (si)
+                        copy = *si;
+
+                if (pidfd_send_signal(s->child.pidfd, sig, si ? &copy : NULL, 0) < 0) {
+                        /* Let's propagate the error only if the system call is not implemented or prohibited */
+                        if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
+                                return -errno;
+                } else
+                        return 0;
+        }
+
+        /* Flags are only supported for pidfd_send_signal(), not for rt_sigqueueinfo(), hence let's refuse
+         * this here. */
+        if (flags != 0)
+                return -EOPNOTSUPP;
+
+        if (si) {
+                /* We use rt_sigqueueinfo() only if siginfo_t is specified. */
+                siginfo_t copy = *si;
+
+                if (rt_sigqueueinfo(s->child.pid, sig, &copy) < 0)
+                        return -errno;
+        } else if (kill(s->child.pid, sig) < 0)
+                return -errno;
+
+        return 0;
+}
+
+_public_ int sd_event_source_get_child_pidfd_own(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+        if (s->child.pidfd < 0)
+                return -EOPNOTSUPP;
+
+        return s->child.pidfd_owned;
+}
+
+_public_ int sd_event_source_set_child_pidfd_own(sd_event_source *s, int own) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+        if (s->child.pidfd < 0)
+                return -EOPNOTSUPP;
+
+        s->child.pidfd_owned = own;
+        return 0;
+}
+
+_public_ int sd_event_source_get_child_process_own(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+        return s->child.process_owned;
+}
+
+_public_ int sd_event_source_set_child_process_own(sd_event_source *s, int own) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type == SOURCE_CHILD, -EDOM);
+
+        s->child.process_owned = own;
+        return 0;
+}
+
+_public_ int sd_event_source_get_inotify_mask(sd_event_source *s, uint32_t *mask) {
+        assert_return(s, -EINVAL);
+        assert_return(mask, -EINVAL);
+        assert_return(s->type == SOURCE_INOTIFY, -EDOM);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        *mask = s->inotify.mask;
+        return 0;
+}
+
+_public_ int sd_event_source_set_prepare(sd_event_source *s, sd_event_handler_t callback) {
+        int r;
+
+        assert_return(s, -EINVAL);
+        assert_return(s->type != SOURCE_EXIT, -EDOM);
+        assert_return(s->event->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(s->event), -ECHILD);
+
+        if (s->prepare == callback)
+                return 0;
+
+        if (callback && s->prepare) {
+                s->prepare = callback;
+                return 0;
+        }
+
+        r = prioq_ensure_allocated(&s->event->prepare, prepare_prioq_compare);
+        if (r < 0)
+                return r;
+
+        s->prepare = callback;
+
+        if (callback) {
+                r = prioq_put(s->event->prepare, s, &s->prepare_index);
+                if (r < 0)
+                        return r;
+        } else
+                prioq_remove(s->event->prepare, s, &s->prepare_index);
+
+        return 0;
+}
+
+_public_ void* sd_event_source_get_userdata(sd_event_source *s) {
+        assert_return(s, NULL);
+
+        return s->userdata;
+}
+
+_public_ void *sd_event_source_set_userdata(sd_event_source *s, void *userdata) {
+        void *ret;
+
+        assert_return(s, NULL);
+
+        ret = s->userdata;
+        s->userdata = userdata;
+
+        return ret;
+}
+
+static usec_t sleep_between(sd_event *e, usec_t a, usec_t b) {
+        usec_t c;
+        assert(e);
+        assert(a <= b);
+
+        if (a <= 0)
+                return 0;
+        if (a >= USEC_INFINITY)
+                return USEC_INFINITY;
+
+        if (b <= a + 1)
+                return a;
+
+        initialize_perturb(e);
+
+        /*
+          Find a good time to wake up again between times a and b. We
+          have two goals here:
+
+          a) We want to wake up as seldom as possible, hence prefer
+             later times over earlier times.
+
+          b) But if we have to wake up, then let's make sure to
+             dispatch as much as possible on the entire system.
+
+          We implement this by waking up everywhere at the same time
+          within any given minute if we can, synchronised via the
+          perturbation value determined from the boot ID. If we can't,
+          then we try to find the same spot in every 10s, then 1s and
+          then 250ms step. Otherwise, we pick the last possible time
+          to wake up.
+        */
+
+        c = (b / USEC_PER_MINUTE) * USEC_PER_MINUTE + e->perturb;
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_MINUTE))
+                        return b;
+
+                c -= USEC_PER_MINUTE;
+        }
+
+        if (c >= a)
+                return c;
+
+        c = (b / (USEC_PER_SEC*10)) * (USEC_PER_SEC*10) + (e->perturb % (USEC_PER_SEC*10));
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_SEC*10))
+                        return b;
+
+                c -= USEC_PER_SEC*10;
+        }
+
+        if (c >= a)
+                return c;
+
+        c = (b / USEC_PER_SEC) * USEC_PER_SEC + (e->perturb % USEC_PER_SEC);
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_SEC))
+                        return b;
+
+                c -= USEC_PER_SEC;
+        }
+
+        if (c >= a)
+                return c;
+
+        c = (b / (USEC_PER_MSEC*250)) * (USEC_PER_MSEC*250) + (e->perturb % (USEC_PER_MSEC*250));
+        if (c >= b) {
+                if (_unlikely_(c < USEC_PER_MSEC*250))
+                        return b;
+
+                c -= USEC_PER_MSEC*250;
+        }
+
+        if (c >= a)
+                return c;
+
+        return b;
+}
+
+static int event_arm_timer(
+                sd_event *e,
+                struct clock_data *d) {
+
+        struct itimerspec its = {};
+        sd_event_source *a, *b;
+        usec_t t;
+
+        assert(e);
+        assert(d);
+
+        if (!d->needs_rearm)
+                return 0;
+        else
+                d->needs_rearm = false;
+
+        a = prioq_peek(d->earliest);
+        if (!a || a->enabled == SD_EVENT_OFF || a->time.next == USEC_INFINITY) {
+
+                if (d->fd < 0)
+                        return 0;
+
+                if (d->next == USEC_INFINITY)
+                        return 0;
+
+                /* disarm */
+                if (timerfd_settime(d->fd, TFD_TIMER_ABSTIME, &its, NULL) < 0)
+                        return -errno;
+
+                d->next = USEC_INFINITY;
+                return 0;
+        }
+
+        b = prioq_peek(d->latest);
+        assert_se(b && b->enabled != SD_EVENT_OFF);
+
+        t = sleep_between(e, a->time.next, time_event_source_latest(b));
+        if (d->next == t)
+                return 0;
+
+        assert_se(d->fd >= 0);
+
+        if (t == 0) {
+                /* We don' want to disarm here, just mean some time looooong ago. */
+                its.it_value.tv_sec = 0;
+                its.it_value.tv_nsec = 1;
+        } else
+                timespec_store(&its.it_value, t);
+
+        if (timerfd_settime(d->fd, TFD_TIMER_ABSTIME, &its, NULL) < 0)
+                return -errno;
+
+        d->next = t;
+        return 0;
+}
+
+static int process_io(sd_event *e, sd_event_source *s, uint32_t revents) {
+        assert(e);
+        assert(s);
+        assert(s->type == SOURCE_IO);
+
+        /* If the event source was already pending, we just OR in the
+         * new revents, otherwise we reset the value. The ORing is
+         * necessary to handle EPOLLONESHOT events properly where
+         * readability might happen independently of writability, and
+         * we need to keep track of both */
+
+        if (s->pending)
+                s->io.revents |= revents;
+        else
+                s->io.revents = revents;
+
+        return source_set_pending(s, true);
+}
+
+static int flush_timer(sd_event *e, int fd, uint32_t events, usec_t *next) {
+        uint64_t x;
+        ssize_t ss;
+
+        assert(e);
+        assert(fd >= 0);
+
+        assert_return(events == EPOLLIN, -EIO);
+
+        ss = read(fd, &x, sizeof(x));
+        if (ss < 0) {
+                if (IN_SET(errno, EAGAIN, EINTR))
+                        return 0;
+
+                return -errno;
+        }
+
+        if (_unlikely_(ss != sizeof(x)))
+                return -EIO;
+
+        if (next)
+                *next = USEC_INFINITY;
+
+        return 0;
+}
+
+static int process_timer(
+                sd_event *e,
+                usec_t n,
+                struct clock_data *d) {
+
+        sd_event_source *s;
+        int r;
+
+        assert(e);
+        assert(d);
+
+        for (;;) {
+                s = prioq_peek(d->earliest);
+                if (!s ||
+                    s->time.next > n ||
+                    s->enabled == SD_EVENT_OFF ||
+                    s->pending)
+                        break;
+
+                r = source_set_pending(s, true);
+                if (r < 0)
+                        return r;
+
+                event_source_time_prioq_reshuffle(s);
+        }
+
+        return 0;
+}
+
+static int process_child(sd_event *e) {
+        sd_event_source *s;
+        int r;
+
+        assert(e);
+
+        e->need_process_child = false;
+
+        /*
+           So, this is ugly. We iteratively invoke waitid() with P_PID
+           + WNOHANG for each PID we wait for, instead of using
+           P_ALL. This is because we only want to get child
+           information of very specific child processes, and not all
+           of them. We might not have processed the SIGCHLD even of a
+           previous invocation and we don't want to maintain a
+           unbounded *per-child* event queue, hence we really don't
+           want anything flushed out of the kernel's queue that we
+           don't care about. Since this is O(n) this means that if you
+           have a lot of processes you probably want to handle SIGCHLD
+           yourself.
+
+           We do not reap the children here (by using WNOWAIT), this
+           is only done after the event source is dispatched so that
+           the callback still sees the process as a zombie.
+        */
+
+        HASHMAP_FOREACH(s, e->child_sources) {
+                assert(s->type == SOURCE_CHILD);
+
+                if (s->pending)
+                        continue;
+
+                if (s->enabled == SD_EVENT_OFF)
+                        continue;
+
+                if (s->child.exited)
+                        continue;
+
+                if (EVENT_SOURCE_WATCH_PIDFD(s)) /* There's a usable pidfd known for this event source? then don't waitid() for it here */
+                        continue;
+
+                zero(s->child.siginfo);
+                if (waitid(P_PID, s->child.pid, &s->child.siginfo,
+                           WNOHANG | (s->child.options & WEXITED ? WNOWAIT : 0) | s->child.options) < 0)
+                        return -errno;
+
+                if (s->child.siginfo.si_pid != 0) {
+                        bool zombie = IN_SET(s->child.siginfo.si_code, CLD_EXITED, CLD_KILLED, CLD_DUMPED);
+
+                        if (zombie)
+                                s->child.exited = true;
+
+                        if (!zombie && (s->child.options & WEXITED)) {
+                                /* If the child isn't dead then let's
+                                 * immediately remove the state change
+                                 * from the queue, since there's no
+                                 * benefit in leaving it queued */
+
+                                assert(s->child.options & (WSTOPPED|WCONTINUED));
+                                (void) waitid(P_PID, s->child.pid, &s->child.siginfo, WNOHANG|(s->child.options & (WSTOPPED|WCONTINUED)));
+                        }
+
+                        r = source_set_pending(s, true);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        return 0;
+}
+
+static int process_pidfd(sd_event *e, sd_event_source *s, uint32_t revents) {
+        assert(e);
+        assert(s);
+        assert(s->type == SOURCE_CHILD);
+
+        if (s->pending)
+                return 0;
+
+        if (s->enabled == SD_EVENT_OFF)
+                return 0;
+
+        if (!EVENT_SOURCE_WATCH_PIDFD(s))
+                return 0;
+
+        zero(s->child.siginfo);
+        if (waitid(P_PID, s->child.pid, &s->child.siginfo, WNOHANG | WNOWAIT | s->child.options) < 0)
+                return -errno;
+
+        if (s->child.siginfo.si_pid == 0)
+                return 0;
+
+        if (IN_SET(s->child.siginfo.si_code, CLD_EXITED, CLD_KILLED, CLD_DUMPED))
+                s->child.exited = true;
+
+        return source_set_pending(s, true);
+}
+
+static int process_signal(sd_event *e, struct signal_data *d, uint32_t events) {
+        bool read_one = false;
+        int r;
+
+        assert(e);
+        assert(d);
+        assert_return(events == EPOLLIN, -EIO);
+
+        /* If there's a signal queued on this priority and SIGCHLD is
+           on this priority too, then make sure to recheck the
+           children we watch. This is because we only ever dequeue
+           the first signal per priority, and if we dequeue one, and
+           SIGCHLD might be enqueued later we wouldn't know, but we
+           might have higher priority children we care about hence we
+           need to check that explicitly. */
+
+        if (sigismember(&d->sigset, SIGCHLD))
+                e->need_process_child = true;
+
+        /* If there's already an event source pending for this
+         * priority we don't read another */
+        if (d->current)
+                return 0;
+
+        for (;;) {
+                struct signalfd_siginfo si;
+                ssize_t n;
+                sd_event_source *s = NULL;
+
+                n = read(d->fd, &si, sizeof(si));
+                if (n < 0) {
+                        if (IN_SET(errno, EAGAIN, EINTR))
+                                return read_one;
+
+                        return -errno;
+                }
+
+                if (_unlikely_(n != sizeof(si)))
+                        return -EIO;
+
+                assert(SIGNAL_VALID(si.ssi_signo));
+
+                read_one = true;
+
+                if (e->signal_sources)
+                        s = e->signal_sources[si.ssi_signo];
+                if (!s)
+                        continue;
+                if (s->pending)
+                        continue;
+
+                s->signal.siginfo = si;
+                d->current = s;
+
+                r = source_set_pending(s, true);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+}
+
+static int event_inotify_data_read(sd_event *e, struct inotify_data *d, uint32_t revents) {
+        ssize_t n;
+
+        assert(e);
+        assert(d);
+
+        assert_return(revents == EPOLLIN, -EIO);
+
+        /* If there's already an event source pending for this priority, don't read another */
+        if (d->n_pending > 0)
+                return 0;
+
+        /* Is the read buffer non-empty? If so, let's not read more */
+        if (d->buffer_filled > 0)
+                return 0;
+
+        n = read(d->fd, &d->buffer, sizeof(d->buffer));
+        if (n < 0) {
+                if (IN_SET(errno, EAGAIN, EINTR))
+                        return 0;
+
+                return -errno;
+        }
+
+        assert(n > 0);
+        d->buffer_filled = (size_t) n;
+        LIST_PREPEND(buffered, e->inotify_data_buffered, d);
+
+        return 1;
+}
+
+static void event_inotify_data_drop(sd_event *e, struct inotify_data *d, size_t sz) {
+        assert(e);
+        assert(d);
+        assert(sz <= d->buffer_filled);
+
+        if (sz == 0)
+                return;
+
+        /* Move the rest to the buffer to the front, in order to get things properly aligned again */
+        memmove(d->buffer.raw, d->buffer.raw + sz, d->buffer_filled - sz);
+        d->buffer_filled -= sz;
+
+        if (d->buffer_filled == 0)
+                LIST_REMOVE(buffered, e->inotify_data_buffered, d);
+}
+
+static int event_inotify_data_process(sd_event *e, struct inotify_data *d) {
+        int r;
+
+        assert(e);
+        assert(d);
+
+        /* If there's already an event source pending for this priority, don't read another */
+        if (d->n_pending > 0)
+                return 0;
+
+        while (d->buffer_filled > 0) {
+                size_t sz;
+
+                /* Let's validate that the event structures are complete */
+                if (d->buffer_filled < offsetof(struct inotify_event, name))
+                        return -EIO;
+
+                sz = offsetof(struct inotify_event, name) + d->buffer.ev.len;
+                if (d->buffer_filled < sz)
+                        return -EIO;
+
+                if (d->buffer.ev.mask & IN_Q_OVERFLOW) {
+                        struct inode_data *inode_data;
+
+                        /* The queue overran, let's pass this event to all event sources connected to this inotify
+                         * object */
+
+                        HASHMAP_FOREACH(inode_data, d->inodes) {
+                                sd_event_source *s;
+
+                                LIST_FOREACH(inotify.by_inode_data, s, inode_data->event_sources) {
+
+                                        if (s->enabled == SD_EVENT_OFF)
+                                                continue;
+
+                                        r = source_set_pending(s, true);
+                                        if (r < 0)
+                                                return r;
+                                }
+                        }
+                } else {
+                        struct inode_data *inode_data;
+                        sd_event_source *s;
+
+                        /* Find the inode object for this watch descriptor. If IN_IGNORED is set we also remove it from
+                         * our watch descriptor table. */
+                        if (d->buffer.ev.mask & IN_IGNORED) {
+
+                                inode_data = hashmap_remove(d->wd, INT_TO_PTR(d->buffer.ev.wd));
+                                if (!inode_data) {
+                                        event_inotify_data_drop(e, d, sz);
+                                        continue;
+                                }
+
+                                /* The watch descriptor was removed by the kernel, let's drop it here too */
+                                inode_data->wd = -1;
+                        } else {
+                                inode_data = hashmap_get(d->wd, INT_TO_PTR(d->buffer.ev.wd));
+                                if (!inode_data) {
+                                        event_inotify_data_drop(e, d, sz);
+                                        continue;
+                                }
+                        }
+
+                        /* Trigger all event sources that are interested in these events. Also trigger all event
+                         * sources if IN_IGNORED or IN_UNMOUNT is set. */
+                        LIST_FOREACH(inotify.by_inode_data, s, inode_data->event_sources) {
+
+                                if (s->enabled == SD_EVENT_OFF)
+                                        continue;
+
+                                if ((d->buffer.ev.mask & (IN_IGNORED|IN_UNMOUNT)) == 0 &&
+                                    (s->inotify.mask & d->buffer.ev.mask & IN_ALL_EVENTS) == 0)
+                                        continue;
+
+                                r = source_set_pending(s, true);
+                                if (r < 0)
+                                        return r;
+                        }
+                }
+
+                /* Something pending now? If so, let's finish, otherwise let's read more. */
+                if (d->n_pending > 0)
+                        return 1;
+        }
+
+        return 0;
+}
+
+static int process_inotify(sd_event *e) {
+        struct inotify_data *d;
+        int r, done = 0;
+
+        assert(e);
+
+        LIST_FOREACH(buffered, d, e->inotify_data_buffered) {
+                r = event_inotify_data_process(e, d);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        done ++;
+        }
+
+        return done;
+}
+
+static int source_dispatch(sd_event_source *s) {
+        _cleanup_(sd_event_unrefp) sd_event *saved_event = NULL;
+        EventSourceType saved_type;
+        int r = 0;
+
+        assert(s);
+        assert(s->pending || s->type == SOURCE_EXIT);
+
+        /* Save the event source type, here, so that we still know it after the event callback which might
+         * invalidate the event. */
+        saved_type = s->type;
+
+        /* Similar, store a reference to the event loop object, so that we can still access it after the
+         * callback might have invalidated/disconnected the event source. */
+        saved_event = sd_event_ref(s->event);
+
+        if (!IN_SET(s->type, SOURCE_DEFER, SOURCE_EXIT)) {
+                r = source_set_pending(s, false);
+                if (r < 0)
+                        return r;
+        }
+
+        if (s->type != SOURCE_POST) {
+                sd_event_source *z;
+
+                /* If we execute a non-post source, let's mark all
+                 * post sources as pending */
+
+                SET_FOREACH(z, s->event->post_sources) {
+                        if (z->enabled == SD_EVENT_OFF)
+                                continue;
+
+                        r = source_set_pending(z, true);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        if (s->enabled == SD_EVENT_ONESHOT) {
+                r = sd_event_source_set_enabled(s, SD_EVENT_OFF);
+                if (r < 0)
+                        return r;
+        }
+
+        s->dispatching = true;
+
+        switch (s->type) {
+
+        case SOURCE_IO:
+                r = s->io.callback(s, s->io.fd, s->io.revents, s->userdata);
+                break;
+
+        case SOURCE_TIME_REALTIME:
+        case SOURCE_TIME_BOOTTIME:
+        case SOURCE_TIME_MONOTONIC:
+        case SOURCE_TIME_REALTIME_ALARM:
+        case SOURCE_TIME_BOOTTIME_ALARM:
+                r = s->time.callback(s, s->time.next, s->userdata);
+                break;
+
+        case SOURCE_SIGNAL:
+                r = s->signal.callback(s, &s->signal.siginfo, s->userdata);
+                break;
+
+        case SOURCE_CHILD: {
+                bool zombie;
+
+                zombie = IN_SET(s->child.siginfo.si_code, CLD_EXITED, CLD_KILLED, CLD_DUMPED);
+
+                r = s->child.callback(s, &s->child.siginfo, s->userdata);
+
+                /* Now, reap the PID for good. */
+                if (zombie) {
+                        (void) waitid(P_PID, s->child.pid, &s->child.siginfo, WNOHANG|WEXITED);
+                        s->child.waited = true;
+                }
+
+                break;
+        }
+
+        case SOURCE_DEFER:
+                r = s->defer.callback(s, s->userdata);
+                break;
+
+        case SOURCE_POST:
+                r = s->post.callback(s, s->userdata);
+                break;
+
+        case SOURCE_EXIT:
+                r = s->exit.callback(s, s->userdata);
+                break;
+
+        case SOURCE_INOTIFY: {
+                struct sd_event *e = s->event;
+                struct inotify_data *d;
+                size_t sz;
+
+                assert(s->inotify.inode_data);
+                assert_se(d = s->inotify.inode_data->inotify_data);
+
+                assert(d->buffer_filled >= offsetof(struct inotify_event, name));
+                sz = offsetof(struct inotify_event, name) + d->buffer.ev.len;
+                assert(d->buffer_filled >= sz);
+
+                r = s->inotify.callback(s, &d->buffer.ev, s->userdata);
+
+                /* When no event is pending anymore on this inotify object, then let's drop the event from the
+                 * buffer. */
+                if (d->n_pending == 0)
+                        event_inotify_data_drop(e, d, sz);
+
+                break;
+        }
+
+        case SOURCE_WATCHDOG:
+        case _SOURCE_EVENT_SOURCE_TYPE_MAX:
+        case _SOURCE_EVENT_SOURCE_TYPE_INVALID:
+                assert_not_reached("Wut? I shouldn't exist.");
+        }
+
+        s->dispatching = false;
+
+        if (r < 0) {
+                log_debug_errno(r, "Event source %s (type %s) returned error, %s: %m",
+                                strna(s->description),
+                                event_source_type_to_string(saved_type),
+                                s->exit_on_failure ? "exiting" : "disabling");
+
+                if (s->exit_on_failure)
+                        (void) sd_event_exit(saved_event, r);
+        }
+
+        if (s->n_ref == 0)
+                source_free(s);
+        else if (r < 0)
+                sd_event_source_set_enabled(s, SD_EVENT_OFF);
+
+        return 1;
+}
+
+static int event_prepare(sd_event *e) {
+        int r;
+
+        assert(e);
+
+        for (;;) {
+                sd_event_source *s;
+
+                s = prioq_peek(e->prepare);
+                if (!s || s->prepare_iteration == e->iteration || s->enabled == SD_EVENT_OFF)
+                        break;
+
+                s->prepare_iteration = e->iteration;
+                r = prioq_reshuffle(e->prepare, s, &s->prepare_index);
+                if (r < 0)
+                        return r;
+
+                assert(s->prepare);
+
+                s->dispatching = true;
+                r = s->prepare(s, s->userdata);
+                s->dispatching = false;
+
+                if (r < 0) {
+                        log_debug_errno(r, "Prepare callback of event source %s (type %s) returned error, %s: %m",
+                                        strna(s->description),
+                                        event_source_type_to_string(s->type),
+                                        s->exit_on_failure ? "exiting" : "disabling");
+
+                        if (s->exit_on_failure)
+                                (void) sd_event_exit(e, r);
+                }
+
+                if (s->n_ref == 0)
+                        source_free(s);
+                else if (r < 0)
+                        sd_event_source_set_enabled(s, SD_EVENT_OFF);
+        }
+
+        return 0;
+}
+
+static int dispatch_exit(sd_event *e) {
+        sd_event_source *p;
+        _cleanup_(sd_event_unrefp) sd_event *ref = NULL;
+        int r;
+
+        assert(e);
+
+        p = prioq_peek(e->exit);
+        if (!p || p->enabled == SD_EVENT_OFF) {
+                e->state = SD_EVENT_FINISHED;
+                return 0;
+        }
+
+        ref = sd_event_ref(e);
+        e->iteration++;
+        e->state = SD_EVENT_EXITING;
+        r = source_dispatch(p);
+        e->state = SD_EVENT_INITIAL;
+        return r;
+}
+
+static sd_event_source* event_next_pending(sd_event *e) {
+        sd_event_source *p;
+
+        assert(e);
+
+        p = prioq_peek(e->pending);
+        if (!p)
+                return NULL;
+
+        if (p->enabled == SD_EVENT_OFF)
+                return NULL;
+
+        return p;
+}
+
+static int arm_watchdog(sd_event *e) {
+        struct itimerspec its = {};
+        usec_t t;
+
+        assert(e);
+        assert(e->watchdog_fd >= 0);
+
+        t = sleep_between(e,
+                          e->watchdog_last + (e->watchdog_period / 2),
+                          e->watchdog_last + (e->watchdog_period * 3 / 4));
+
+        timespec_store(&its.it_value, t);
+
+        /* Make sure we never set the watchdog to 0, which tells the
+         * kernel to disable it. */
+        if (its.it_value.tv_sec == 0 && its.it_value.tv_nsec == 0)
+                its.it_value.tv_nsec = 1;
+
+        if (timerfd_settime(e->watchdog_fd, TFD_TIMER_ABSTIME, &its, NULL) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int process_watchdog(sd_event *e) {
+        assert(e);
+
+        if (!e->watchdog)
+                return 0;
+
+        /* Don't notify watchdog too often */
+        if (e->watchdog_last + e->watchdog_period / 4 > e->timestamp.monotonic)
+                return 0;
+
+        sd_notify(false, "WATCHDOG=1");
+        e->watchdog_last = e->timestamp.monotonic;
+
+        return arm_watchdog(e);
+}
+
+static void event_close_inode_data_fds(sd_event *e) {
+        struct inode_data *d;
+
+        assert(e);
+
+        /* Close the fds pointing to the inodes to watch now. We need to close them as they might otherwise pin
+         * filesystems. But we can't close them right-away as we need them as long as the user still wants to make
+         * adjustments to the even source, such as changing the priority (which requires us to remove and re-add a watch
+         * for the inode). Hence, let's close them when entering the first iteration after they were added, as a
+         * compromise. */
+
+        while ((d = e->inode_data_to_close)) {
+                assert(d->fd >= 0);
+                d->fd = safe_close(d->fd);
+
+                LIST_REMOVE(to_close, e->inode_data_to_close, d);
+        }
+}
+
+_public_ int sd_event_prepare(sd_event *e) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
+
+        /* Let's check that if we are a default event loop we are executed in the correct thread. We only do
+         * this check here once, since gettid() is typically not cached, and thus want to minimize
+         * syscalls */
+        assert_return(!e->default_event_ptr || e->tid == gettid(), -EREMOTEIO);
+
+        if (e->exit_requested)
+                goto pending;
+
+        e->iteration++;
+
+        e->state = SD_EVENT_PREPARING;
+        r = event_prepare(e);
+        e->state = SD_EVENT_INITIAL;
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->realtime);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->boottime);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->monotonic);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->realtime_alarm);
+        if (r < 0)
+                return r;
+
+        r = event_arm_timer(e, &e->boottime_alarm);
+        if (r < 0)
+                return r;
+
+        event_close_inode_data_fds(e);
+
+        if (event_next_pending(e) || e->need_process_child)
+                goto pending;
+
+        e->state = SD_EVENT_ARMED;
+
+        return 0;
+
+pending:
+        e->state = SD_EVENT_ARMED;
+        r = sd_event_wait(e, 0);
+        if (r == 0)
+                e->state = SD_EVENT_ARMED;
+
+        return r;
+}
+
+_public_ int sd_event_wait(sd_event *e, uint64_t timeout) {
+        size_t event_queue_max;
+        int r, m, i;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_ARMED, -EBUSY);
+
+        if (e->exit_requested) {
+                e->state = SD_EVENT_PENDING;
+                return 1;
+        }
+
+        event_queue_max = MAX(e->n_sources, 1u);
+        if (!GREEDY_REALLOC(e->event_queue, e->event_queue_allocated, event_queue_max))
+                return -ENOMEM;
+
+        /* If we still have inotify data buffered, then query the other fds, but don't wait on it */
+        if (e->inotify_data_buffered)
+                timeout = 0;
+
+        m = epoll_wait(e->epoll_fd, e->event_queue, event_queue_max,
+                       timeout == (uint64_t) -1 ? -1 : (int) DIV_ROUND_UP(timeout, USEC_PER_MSEC));
+        if (m < 0) {
+                if (errno == EINTR) {
+                        e->state = SD_EVENT_PENDING;
+                        return 1;
+                }
+
+                r = -errno;
+                goto finish;
+        }
+
+        triple_timestamp_get(&e->timestamp);
+
+        for (i = 0; i < m; i++) {
+
+                if (e->event_queue[i].data.ptr == INT_TO_PTR(SOURCE_WATCHDOG))
+                        r = flush_timer(e, e->watchdog_fd, e->event_queue[i].events, NULL);
+                else {
+                        WakeupType *t = e->event_queue[i].data.ptr;
+
+                        switch (*t) {
+
+                        case WAKEUP_EVENT_SOURCE: {
+                                sd_event_source *s = e->event_queue[i].data.ptr;
+
+                                assert(s);
+
+                                switch (s->type) {
+
+                                case SOURCE_IO:
+                                        r = process_io(e, s, e->event_queue[i].events);
+                                        break;
+
+                                case SOURCE_CHILD:
+                                        r = process_pidfd(e, s, e->event_queue[i].events);
+                                        break;
+
+                                default:
+                                        assert_not_reached("Unexpected event source type");
+                                }
+
+                                break;
+                        }
+
+                        case WAKEUP_CLOCK_DATA: {
+                                struct clock_data *d = e->event_queue[i].data.ptr;
+
+                                assert(d);
+
+                                r = flush_timer(e, d->fd, e->event_queue[i].events, &d->next);
+                                break;
+                        }
+
+                        case WAKEUP_SIGNAL_DATA:
+                                r = process_signal(e, e->event_queue[i].data.ptr, e->event_queue[i].events);
+                                break;
+
+                        case WAKEUP_INOTIFY_DATA:
+                                r = event_inotify_data_read(e, e->event_queue[i].data.ptr, e->event_queue[i].events);
+                                break;
+
+                        default:
+                                assert_not_reached("Invalid wake-up pointer");
+                        }
+                }
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = process_watchdog(e);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.realtime, &e->realtime);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.boottime, &e->boottime);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.monotonic, &e->monotonic);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.realtime, &e->realtime_alarm);
+        if (r < 0)
+                goto finish;
+
+        r = process_timer(e, e->timestamp.boottime, &e->boottime_alarm);
+        if (r < 0)
+                goto finish;
+
+        if (e->need_process_child) {
+                r = process_child(e);
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = process_inotify(e);
+        if (r < 0)
+                goto finish;
+
+        if (event_next_pending(e)) {
+                e->state = SD_EVENT_PENDING;
+
+                return 1;
+        }
+
+        r = 0;
+
+finish:
+        e->state = SD_EVENT_INITIAL;
+
+        return r;
+}
+
+_public_ int sd_event_dispatch(sd_event *e) {
+        sd_event_source *p;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_PENDING, -EBUSY);
+
+        if (e->exit_requested)
+                return dispatch_exit(e);
+
+        p = event_next_pending(e);
+        if (p) {
+                _cleanup_(sd_event_unrefp) sd_event *ref = NULL;
+
+                ref = sd_event_ref(e);
+                e->state = SD_EVENT_RUNNING;
+                r = source_dispatch(p);
+                e->state = SD_EVENT_INITIAL;
+                return r;
+        }
+
+        e->state = SD_EVENT_INITIAL;
+
+        return 1;
+}
+
+static void event_log_delays(sd_event *e) {
+        char b[ELEMENTSOF(e->delays) * DECIMAL_STR_MAX(unsigned) + 1], *p;
+        size_t l, i;
+
+        p = b;
+        l = sizeof(b);
+        for (i = 0; i < ELEMENTSOF(e->delays); i++) {
+                l = strpcpyf(&p, l, "%u ", e->delays[i]);
+                e->delays[i] = 0;
+        }
+        log_debug("Event loop iterations: %s", b);
+}
+
+_public_ int sd_event_run(sd_event *e, uint64_t timeout) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
+
+        if (e->profile_delays && e->last_run) {
+                usec_t this_run;
+                unsigned l;
+
+                this_run = now(CLOCK_MONOTONIC);
+
+                l = u64log2(this_run - e->last_run);
+                assert(l < ELEMENTSOF(e->delays));
+                e->delays[l]++;
+
+                if (this_run - e->last_log >= 5*USEC_PER_SEC) {
+                        event_log_delays(e);
+                        e->last_log = this_run;
+                }
+        }
+
+        r = sd_event_prepare(e);
+        if (r == 0)
+                /* There was nothing? Then wait... */
+                r = sd_event_wait(e, timeout);
+
+        if (e->profile_delays)
+                e->last_run = now(CLOCK_MONOTONIC);
+
+        if (r > 0) {
+                /* There's something now, then let's dispatch it */
+                r = sd_event_dispatch(e);
+                if (r < 0)
+                        return r;
+
+                return 1;
+        }
+
+        return r;
+}
+
+_public_ int sd_event_loop(sd_event *e) {
+        _cleanup_(sd_event_unrefp) sd_event *ref = NULL;
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+        assert_return(e->state == SD_EVENT_INITIAL, -EBUSY);
+
+        ref = sd_event_ref(e);
+
+        while (e->state != SD_EVENT_FINISHED) {
+                r = sd_event_run(e, (uint64_t) -1);
+                if (r < 0)
+                        return r;
+        }
+
+        return e->exit_code;
+}
+
+_public_ int sd_event_get_fd(sd_event *e) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        return e->epoll_fd;
+}
+
+_public_ int sd_event_get_state(sd_event *e) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        return e->state;
+}
+
+_public_ int sd_event_get_exit_code(sd_event *e, int *code) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(code, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!e->exit_requested)
+                return -ENODATA;
+
+        *code = e->exit_code;
+        return 0;
+}
+
+_public_ int sd_event_exit(sd_event *e, int code) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(e->state != SD_EVENT_FINISHED, -ESTALE);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        e->exit_requested = true;
+        e->exit_code = code;
+
+        return 0;
+}
+
+_public_ int sd_event_now(sd_event *e, clockid_t clock, uint64_t *usec) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(usec, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (!TRIPLE_TIMESTAMP_HAS_CLOCK(clock))
+                return -EOPNOTSUPP;
+
+        /* Generate a clean error in case CLOCK_BOOTTIME is not available. Note that don't use clock_supported() here,
+         * for a reason: there are systems where CLOCK_BOOTTIME is supported, but CLOCK_BOOTTIME_ALARM is not, but for
+         * the purpose of getting the time this doesn't matter. */
+        if (IN_SET(clock, CLOCK_BOOTTIME, CLOCK_BOOTTIME_ALARM) && !clock_boottime_supported())
+                return -EOPNOTSUPP;
+
+        if (!triple_timestamp_is_set(&e->timestamp)) {
+                /* Implicitly fall back to now() if we never ran before and thus have no cached time. */
+                *usec = now(clock);
+                return 1;
+        }
+
+        *usec = triple_timestamp_by_clock(&e->timestamp, clock);
+        return 0;
+}
+
+_public_ int sd_event_default(sd_event **ret) {
+        sd_event *e = NULL;
+        int r;
+
+        if (!ret)
+                return !!default_event;
+
+        if (default_event) {
+                *ret = sd_event_ref(default_event);
+                return 0;
+        }
+
+        r = sd_event_new(&e);
+        if (r < 0)
+                return r;
+
+        e->default_event_ptr = &default_event;
+        e->tid = gettid();
+        default_event = e;
+
+        *ret = e;
+        return 1;
+}
+
+_public_ int sd_event_get_tid(sd_event *e, pid_t *tid) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(tid, -EINVAL);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (e->tid != 0) {
+                *tid = e->tid;
+                return 0;
+        }
+
+        return -ENXIO;
+}
+
+_public_ int sd_event_set_watchdog(sd_event *e, int b) {
+        int r;
+
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        if (e->watchdog == !!b)
+                return e->watchdog;
+
+        if (b) {
+                r = sd_watchdog_enabled(false, &e->watchdog_period);
+                if (r <= 0)
+                        return r;
+
+                /* Issue first ping immediately */
+                sd_notify(false, "WATCHDOG=1");
+                e->watchdog_last = now(CLOCK_MONOTONIC);
+
+                e->watchdog_fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC);
+                if (e->watchdog_fd < 0)
+                        return -errno;
+
+                r = arm_watchdog(e);
+                if (r < 0)
+                        goto fail;
+
+                struct epoll_event ev = {
+                        .events = EPOLLIN,
+                        .data.ptr = INT_TO_PTR(SOURCE_WATCHDOG),
+                };
+
+                if (epoll_ctl(e->epoll_fd, EPOLL_CTL_ADD, e->watchdog_fd, &ev) < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+
+        } else {
+                if (e->watchdog_fd >= 0) {
+                        (void) epoll_ctl(e->epoll_fd, EPOLL_CTL_DEL, e->watchdog_fd, NULL);
+                        e->watchdog_fd = safe_close(e->watchdog_fd);
+                }
+        }
+
+        e->watchdog = !!b;
+        return e->watchdog;
+
+fail:
+        e->watchdog_fd = safe_close(e->watchdog_fd);
+        return r;
+}
+
+_public_ int sd_event_get_watchdog(sd_event *e) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        return e->watchdog;
+}
+
+_public_ int sd_event_get_iteration(sd_event *e, uint64_t *ret) {
+        assert_return(e, -EINVAL);
+        assert_return(e = event_resolve(e), -ENOPKG);
+        assert_return(!event_pid_changed(e), -ECHILD);
+
+        *ret = e->iteration;
+        return 0;
+}
+
+_public_ int sd_event_source_set_destroy_callback(sd_event_source *s, sd_event_destroy_t callback) {
+        assert_return(s, -EINVAL);
+
+        s->destroy_callback = callback;
+        return 0;
+}
+
+_public_ int sd_event_source_get_destroy_callback(sd_event_source *s, sd_event_destroy_t *ret) {
+        assert_return(s, -EINVAL);
+
+        if (ret)
+                *ret = s->destroy_callback;
+
+        return !!s->destroy_callback;
+}
+
+_public_ int sd_event_source_get_floating(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+
+        return s->floating;
+}
+
+_public_ int sd_event_source_set_floating(sd_event_source *s, int b) {
+        assert_return(s, -EINVAL);
+
+        if (s->floating == !!b)
+                return 0;
+
+        if (!s->event) /* Already disconnected */
+                return -ESTALE;
+
+        s->floating = b;
+
+        if (b) {
+                sd_event_source_ref(s);
+                sd_event_unref(s->event);
+        } else {
+                sd_event_ref(s->event);
+                sd_event_source_unref(s);
+        }
+
+        return 1;
+}
+
+_public_ int sd_event_source_get_exit_on_failure(sd_event_source *s) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type != SOURCE_EXIT, -EDOM);
+
+        return s->exit_on_failure;
+}
+
+_public_ int sd_event_source_set_exit_on_failure(sd_event_source *s, int b) {
+        assert_return(s, -EINVAL);
+        assert_return(s->type != SOURCE_EXIT, -EDOM);
+
+        if (s->exit_on_failure == !!b)
+                return 0;
+
+        s->exit_on_failure = b;
+        return 1;
+}
diff --git a/src/libsystemd/sd-event/test-event.c b/src/libsystemd/sd-event/test-event.c
new file mode 100644
index 0000000..1c4d0e2
--- /dev/null
+++ b/src/libsystemd/sd-event/test-event.c
@@ -0,0 +1,607 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/wait.h>
+
+#include "sd-event.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "log.h"
+#include "macro.h"
+#include "missing_syscall.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "rm-rf.h"
+#include "signal-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "tests.h"
+#include "tmpfile-util.h"
+#include "util.h"
+
+static int prepare_handler(sd_event_source *s, void *userdata) {
+        log_info("preparing %c", PTR_TO_INT(userdata));
+        return 1;
+}
+
+static bool got_a, got_b, got_c, got_unref;
+static unsigned got_d;
+
+static int unref_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_event_source_unref(s);
+        got_unref = true;
+        return 0;
+}
+
+static int io_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+
+        log_info("got IO on %c", PTR_TO_INT(userdata));
+
+        if (userdata == INT_TO_PTR('a')) {
+                assert_se(sd_event_source_set_enabled(s, SD_EVENT_OFF) >= 0);
+                assert_se(!got_a);
+                got_a = true;
+        } else if (userdata == INT_TO_PTR('b')) {
+                assert_se(!got_b);
+                got_b = true;
+        } else if (userdata == INT_TO_PTR('d')) {
+                got_d++;
+                if (got_d < 2)
+                        assert_se(sd_event_source_set_enabled(s, SD_EVENT_ONESHOT) >= 0);
+                else
+                        assert_se(sd_event_source_set_enabled(s, SD_EVENT_OFF) >= 0);
+        } else
+                assert_not_reached("Yuck!");
+
+        return 1;
+}
+
+static int child_handler(sd_event_source *s, const siginfo_t *si, void *userdata) {
+
+        assert_se(s);
+        assert_se(si);
+
+        assert_se(si->si_uid == getuid());
+        assert_se(si->si_signo == SIGCHLD);
+        assert_se(si->si_code == CLD_EXITED);
+        assert_se(si->si_status == 78);
+
+        log_info("got child on %c", PTR_TO_INT(userdata));
+
+        assert_se(userdata == INT_TO_PTR('f'));
+
+        assert_se(sd_event_exit(sd_event_source_get_event(s), 0) >= 0);
+        sd_event_source_unref(s);
+
+        return 1;
+}
+
+static int signal_handler(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+        sd_event_source *p = NULL;
+        pid_t pid;
+        siginfo_t plain_si;
+
+        assert_se(s);
+        assert_se(si);
+
+        log_info("got signal on %c", PTR_TO_INT(userdata));
+
+        assert_se(userdata == INT_TO_PTR('e'));
+
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGCHLD, SIGUSR2, -1) >= 0);
+
+        pid = fork();
+        assert_se(pid >= 0);
+
+        if (pid == 0) {
+                sigset_t ss;
+
+                assert_se(sigemptyset(&ss) >= 0);
+                assert_se(sigaddset(&ss, SIGUSR2) >= 0);
+
+                zero(plain_si);
+                assert_se(sigwaitinfo(&ss, &plain_si) >= 0);
+
+                assert_se(plain_si.si_signo == SIGUSR2);
+                assert_se(plain_si.si_value.sival_int == 4711);
+
+                _exit(78);
+        }
+
+        assert_se(sd_event_add_child(sd_event_source_get_event(s), &p, pid, WEXITED, child_handler, INT_TO_PTR('f')) >= 0);
+        assert_se(sd_event_source_set_enabled(p, SD_EVENT_ONESHOT) >= 0);
+        assert_se(sd_event_source_set_child_process_own(p, true) >= 0);
+
+        /* We can't use structured initialization here, since the structure contains various unions and these
+         * fields lie in overlapping (carefully aligned) unions that LLVM is allergic to allow assignments
+         * to */
+        zero(plain_si);
+        plain_si.si_signo = SIGUSR2;
+        plain_si.si_code = SI_QUEUE;
+        plain_si.si_pid = getpid();
+        plain_si.si_uid = getuid();
+        plain_si.si_value.sival_int = 4711;
+
+        assert_se(sd_event_source_send_child_signal(p, SIGUSR2, &plain_si, 0) >= 0);
+
+        sd_event_source_unref(s);
+
+        return 1;
+}
+
+static int defer_handler(sd_event_source *s, void *userdata) {
+        sd_event_source *p = NULL;
+
+        assert_se(s);
+
+        log_info("got defer on %c", PTR_TO_INT(userdata));
+
+        assert_se(userdata == INT_TO_PTR('d'));
+
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGUSR1, -1) >= 0);
+
+        assert_se(sd_event_add_signal(sd_event_source_get_event(s), &p, SIGUSR1, signal_handler, INT_TO_PTR('e')) >= 0);
+        assert_se(sd_event_source_set_enabled(p, SD_EVENT_ONESHOT) >= 0);
+        raise(SIGUSR1);
+
+        sd_event_source_unref(s);
+
+        return 1;
+}
+
+static bool do_quit;
+
+static int time_handler(sd_event_source *s, uint64_t usec, void *userdata) {
+        log_info("got timer on %c", PTR_TO_INT(userdata));
+
+        if (userdata == INT_TO_PTR('c')) {
+
+                if (do_quit) {
+                        sd_event_source *p;
+
+                        assert_se(sd_event_add_defer(sd_event_source_get_event(s), &p, defer_handler, INT_TO_PTR('d')) >= 0);
+                        assert_se(sd_event_source_set_enabled(p, SD_EVENT_ONESHOT) >= 0);
+                } else {
+                        assert_se(!got_c);
+                        got_c = true;
+                }
+        } else
+                assert_not_reached("Huh?");
+
+        return 2;
+}
+
+static bool got_exit = false;
+
+static int exit_handler(sd_event_source *s, void *userdata) {
+        log_info("got quit handler on %c", PTR_TO_INT(userdata));
+
+        got_exit = true;
+
+        return 3;
+}
+
+static bool got_post = false;
+
+static int post_handler(sd_event_source *s, void *userdata) {
+        log_info("got post handler");
+
+        got_post = true;
+
+        return 2;
+}
+
+static void test_basic(bool with_pidfd) {
+        sd_event *e = NULL;
+        sd_event_source *w = NULL, *x = NULL, *y = NULL, *z = NULL, *q = NULL, *t = NULL;
+        static const char ch = 'x';
+        int a[2] = { -1, -1 }, b[2] = { -1, -1}, d[2] = { -1, -1}, k[2] = { -1, -1 };
+        uint64_t event_now;
+        int64_t priority;
+
+        assert_se(setenv("SYSTEMD_PIDFD", yes_no(with_pidfd), 1) >= 0);
+
+        assert_se(pipe(a) >= 0);
+        assert_se(pipe(b) >= 0);
+        assert_se(pipe(d) >= 0);
+        assert_se(pipe(k) >= 0);
+
+        assert_se(sd_event_default(&e) >= 0);
+        assert_se(sd_event_now(e, CLOCK_MONOTONIC, &event_now) > 0);
+
+        assert_se(sd_event_set_watchdog(e, true) >= 0);
+
+        /* Test whether we cleanly can destroy an io event source from its own handler */
+        got_unref = false;
+        assert_se(sd_event_add_io(e, &t, k[0], EPOLLIN, unref_handler, NULL) >= 0);
+        assert_se(write(k[1], &ch, 1) == 1);
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(got_unref);
+
+        got_a = false, got_b = false, got_c = false, got_d = 0;
+
+        /* Add a oneshot handler, trigger it, reenable it, and trigger
+         * it again. */
+        assert_se(sd_event_add_io(e, &w, d[0], EPOLLIN, io_handler, INT_TO_PTR('d')) >= 0);
+        assert_se(sd_event_source_set_enabled(w, SD_EVENT_ONESHOT) >= 0);
+        assert_se(write(d[1], &ch, 1) >= 0);
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(got_d == 1);
+        assert_se(write(d[1], &ch, 1) >= 0);
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(got_d == 2);
+
+        assert_se(sd_event_add_io(e, &x, a[0], EPOLLIN, io_handler, INT_TO_PTR('a')) >= 0);
+        assert_se(sd_event_add_io(e, &y, b[0], EPOLLIN, io_handler, INT_TO_PTR('b')) >= 0);
+
+        do_quit = false;
+        assert_se(sd_event_add_time(e, &z, CLOCK_MONOTONIC, 0, 0, time_handler, INT_TO_PTR('c')) >= 0);
+        assert_se(sd_event_add_exit(e, &q, exit_handler, INT_TO_PTR('g')) >= 0);
+
+        assert_se(sd_event_source_set_priority(x, 99) >= 0);
+        assert_se(sd_event_source_get_priority(x, &priority) >= 0);
+        assert_se(priority == 99);
+        assert_se(sd_event_source_set_enabled(y, SD_EVENT_ONESHOT) >= 0);
+        assert_se(sd_event_source_set_prepare(x, prepare_handler) >= 0);
+        assert_se(sd_event_source_set_priority(z, 50) >= 0);
+        assert_se(sd_event_source_set_enabled(z, SD_EVENT_ONESHOT) >= 0);
+        assert_se(sd_event_source_set_prepare(z, prepare_handler) >= 0);
+
+        /* Test for floating event sources */
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGRTMIN+1, -1) >= 0);
+        assert_se(sd_event_add_signal(e, NULL, SIGRTMIN+1, NULL, NULL) >= 0);
+
+        assert_se(write(a[1], &ch, 1) >= 0);
+        assert_se(write(b[1], &ch, 1) >= 0);
+
+        assert_se(!got_a && !got_b && !got_c);
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+
+        assert_se(!got_a && got_b && !got_c);
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+
+        assert_se(!got_a && got_b && got_c);
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+
+        assert_se(got_a && got_b && got_c);
+
+        sd_event_source_unref(x);
+        sd_event_source_unref(y);
+
+        do_quit = true;
+        assert_se(sd_event_add_post(e, NULL, post_handler, NULL) >= 0);
+        assert_se(sd_event_now(e, CLOCK_MONOTONIC, &event_now) == 0);
+        assert_se(sd_event_source_set_time(z, event_now + 200 * USEC_PER_MSEC) >= 0);
+        assert_se(sd_event_source_set_enabled(z, SD_EVENT_ONESHOT) >= 0);
+
+        assert_se(sd_event_loop(e) >= 0);
+        assert_se(got_post);
+        assert_se(got_exit);
+
+        sd_event_source_unref(z);
+        sd_event_source_unref(q);
+
+        sd_event_source_unref(w);
+
+        sd_event_unref(e);
+
+        safe_close_pair(a);
+        safe_close_pair(b);
+        safe_close_pair(d);
+        safe_close_pair(k);
+
+        assert_se(unsetenv("SYSTEMD_PIDFD") >= 0);
+}
+
+static void test_sd_event_now(void) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+        uint64_t event_now;
+
+        assert_se(sd_event_new(&e) >= 0);
+        assert_se(sd_event_now(e, CLOCK_MONOTONIC, &event_now) > 0);
+        assert_se(sd_event_now(e, CLOCK_REALTIME, &event_now) > 0);
+        assert_se(sd_event_now(e, CLOCK_REALTIME_ALARM, &event_now) > 0);
+        if (clock_boottime_supported()) {
+                assert_se(sd_event_now(e, CLOCK_BOOTTIME, &event_now) > 0);
+                assert_se(sd_event_now(e, CLOCK_BOOTTIME_ALARM, &event_now) > 0);
+        }
+        assert_se(sd_event_now(e, -1, &event_now) == -EOPNOTSUPP);
+        assert_se(sd_event_now(e, 900 /* arbitrary big number */, &event_now) == -EOPNOTSUPP);
+
+        assert_se(sd_event_run(e, 0) == 0);
+
+        assert_se(sd_event_now(e, CLOCK_MONOTONIC, &event_now) == 0);
+        assert_se(sd_event_now(e, CLOCK_REALTIME, &event_now) == 0);
+        assert_se(sd_event_now(e, CLOCK_REALTIME_ALARM, &event_now) == 0);
+        if (clock_boottime_supported()) {
+                assert_se(sd_event_now(e, CLOCK_BOOTTIME, &event_now) == 0);
+                assert_se(sd_event_now(e, CLOCK_BOOTTIME_ALARM, &event_now) == 0);
+        }
+        assert_se(sd_event_now(e, -1, &event_now) == -EOPNOTSUPP);
+        assert_se(sd_event_now(e, 900 /* arbitrary big number */, &event_now) == -EOPNOTSUPP);
+}
+
+static int last_rtqueue_sigval = 0;
+static int n_rtqueue = 0;
+
+static int rtqueue_handler(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+        last_rtqueue_sigval = si->ssi_int;
+        n_rtqueue++;
+        return 0;
+}
+
+static void test_rtqueue(void) {
+        sd_event_source *u = NULL, *v = NULL, *s = NULL;
+        sd_event *e = NULL;
+
+        assert_se(sd_event_default(&e) >= 0);
+
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGRTMIN+2, SIGRTMIN+3, SIGUSR2, -1) >= 0);
+        assert_se(sd_event_add_signal(e, &u, SIGRTMIN+2, rtqueue_handler, NULL) >= 0);
+        assert_se(sd_event_add_signal(e, &v, SIGRTMIN+3, rtqueue_handler, NULL) >= 0);
+        assert_se(sd_event_add_signal(e, &s, SIGUSR2, rtqueue_handler, NULL) >= 0);
+
+        assert_se(sd_event_source_set_priority(v, -10) >= 0);
+
+        assert_se(sigqueue(getpid_cached(), SIGRTMIN+2, (union sigval) { .sival_int = 1 }) >= 0);
+        assert_se(sigqueue(getpid_cached(), SIGRTMIN+3, (union sigval) { .sival_int = 2 }) >= 0);
+        assert_se(sigqueue(getpid_cached(), SIGUSR2, (union sigval) { .sival_int = 3 }) >= 0);
+        assert_se(sigqueue(getpid_cached(), SIGRTMIN+3, (union sigval) { .sival_int = 4 }) >= 0);
+        assert_se(sigqueue(getpid_cached(), SIGUSR2, (union sigval) { .sival_int = 5 }) >= 0);
+
+        assert_se(n_rtqueue == 0);
+        assert_se(last_rtqueue_sigval == 0);
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(n_rtqueue == 1);
+        assert_se(last_rtqueue_sigval == 2); /* first SIGRTMIN+3 */
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(n_rtqueue == 2);
+        assert_se(last_rtqueue_sigval == 4); /* second SIGRTMIN+3 */
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(n_rtqueue == 3);
+        assert_se(last_rtqueue_sigval == 3); /* first SIGUSR2 */
+
+        assert_se(sd_event_run(e, (uint64_t) -1) >= 1);
+        assert_se(n_rtqueue == 4);
+        assert_se(last_rtqueue_sigval == 1); /* SIGRTMIN+2 */
+
+        assert_se(sd_event_run(e, 0) == 0); /* the other SIGUSR2 is dropped, because the first one was still queued */
+        assert_se(n_rtqueue == 4);
+        assert_se(last_rtqueue_sigval == 1);
+
+        sd_event_source_unref(u);
+        sd_event_source_unref(v);
+        sd_event_source_unref(s);
+
+        sd_event_unref(e);
+}
+
+#define CREATE_EVENTS_MAX (70000U)
+
+struct inotify_context {
+        bool delete_self_handler_called;
+        unsigned create_called[CREATE_EVENTS_MAX];
+        unsigned create_overflow;
+        unsigned n_create_events;
+};
+
+static void maybe_exit(sd_event_source *s, struct inotify_context *c) {
+        unsigned n;
+
+        assert(s);
+        assert(c);
+
+        if (!c->delete_self_handler_called)
+                return;
+
+        for (n = 0; n < 3; n++) {
+                unsigned i;
+
+                if (c->create_overflow & (1U << n))
+                        continue;
+
+                for (i = 0; i < c->n_create_events; i++)
+                        if (!(c->create_called[i] & (1U << n)))
+                                return;
+        }
+
+        sd_event_exit(sd_event_source_get_event(s), 0);
+}
+
+static int inotify_handler(sd_event_source *s, const struct inotify_event *ev, void *userdata) {
+        struct inotify_context *c = userdata;
+        const char *description;
+        unsigned bit, n;
+
+        assert_se(sd_event_source_get_description(s, &description) >= 0);
+        assert_se(safe_atou(description, &n) >= 0);
+
+        assert_se(n <= 3);
+        bit = 1U << n;
+
+        if (ev->mask & IN_Q_OVERFLOW) {
+                log_info("inotify-handler <%s>: overflow", description);
+                c->create_overflow |= bit;
+        } else if (ev->mask & IN_CREATE) {
+                unsigned i;
+
+                log_debug("inotify-handler <%s>: create on %s", description, ev->name);
+
+                if (!streq(ev->name, "sub")) {
+                        assert_se(safe_atou(ev->name, &i) >= 0);
+
+                        assert_se(i < c->n_create_events);
+                        c->create_called[i] |= bit;
+                }
+        } else if (ev->mask & IN_DELETE) {
+                log_info("inotify-handler <%s>: delete of %s", description, ev->name);
+                assert_se(streq(ev->name, "sub"));
+        } else
+                assert_not_reached("unexpected inotify event");
+
+        maybe_exit(s, c);
+        return 1;
+}
+
+static int delete_self_handler(sd_event_source *s, const struct inotify_event *ev, void *userdata) {
+        struct inotify_context *c = userdata;
+
+        if (ev->mask & IN_Q_OVERFLOW) {
+                log_info("delete-self-handler: overflow");
+                c->delete_self_handler_called = true;
+        } else if (ev->mask & IN_DELETE_SELF) {
+                log_info("delete-self-handler: delete-self");
+                c->delete_self_handler_called = true;
+        } else if (ev->mask & IN_IGNORED) {
+                log_info("delete-self-handler: ignore");
+        } else
+                assert_not_reached("unexpected inotify event (delete-self)");
+
+        maybe_exit(s, c);
+        return 1;
+}
+
+static void test_inotify(unsigned n_create_events) {
+        _cleanup_(rm_rf_physical_and_freep) char *p = NULL;
+        sd_event_source *a = NULL, *b = NULL, *c = NULL, *d = NULL;
+        struct inotify_context context = {
+                .n_create_events = n_create_events,
+        };
+        sd_event *e = NULL;
+        const char *q;
+        unsigned i;
+
+        assert_se(sd_event_default(&e) >= 0);
+
+        assert_se(mkdtemp_malloc("/tmp/test-inotify-XXXXXX", &p) >= 0);
+
+        assert_se(sd_event_add_inotify(e, &a, p, IN_CREATE|IN_ONLYDIR, inotify_handler, &context) >= 0);
+        assert_se(sd_event_add_inotify(e, &b, p, IN_CREATE|IN_DELETE|IN_DONT_FOLLOW, inotify_handler, &context) >= 0);
+        assert_se(sd_event_source_set_priority(b, SD_EVENT_PRIORITY_IDLE) >= 0);
+        assert_se(sd_event_source_set_priority(b, SD_EVENT_PRIORITY_NORMAL) >= 0);
+        assert_se(sd_event_add_inotify(e, &c, p, IN_CREATE|IN_DELETE|IN_EXCL_UNLINK, inotify_handler, &context) >= 0);
+        assert_se(sd_event_source_set_priority(c, SD_EVENT_PRIORITY_IDLE) >= 0);
+
+        assert_se(sd_event_source_set_description(a, "0") >= 0);
+        assert_se(sd_event_source_set_description(b, "1") >= 0);
+        assert_se(sd_event_source_set_description(c, "2") >= 0);
+
+        q = strjoina(p, "/sub");
+        assert_se(touch(q) >= 0);
+        assert_se(sd_event_add_inotify(e, &d, q, IN_DELETE_SELF, delete_self_handler, &context) >= 0);
+
+        for (i = 0; i < n_create_events; i++) {
+                char buf[DECIMAL_STR_MAX(unsigned)+1];
+                _cleanup_free_ char *z;
+
+                xsprintf(buf, "%u", i);
+                assert_se(z = path_join(p, buf));
+
+                assert_se(touch(z) >= 0);
+        }
+
+        assert_se(unlink(q) >= 0);
+
+        assert_se(sd_event_loop(e) >= 0);
+
+        sd_event_source_unref(a);
+        sd_event_source_unref(b);
+        sd_event_source_unref(c);
+        sd_event_source_unref(d);
+
+        sd_event_unref(e);
+}
+
+static int pidfd_handler(sd_event_source *s, const siginfo_t *si, void *userdata) {
+        assert_se(s);
+        assert_se(si);
+
+        assert_se(si->si_uid == getuid());
+        assert_se(si->si_signo == SIGCHLD);
+        assert_se(si->si_code == CLD_EXITED);
+        assert_se(si->si_status == 66);
+
+        log_info("got pidfd on %c", PTR_TO_INT(userdata));
+
+        assert_se(userdata == INT_TO_PTR('p'));
+
+        assert_se(sd_event_exit(sd_event_source_get_event(s), 0) >= 0);
+        sd_event_source_unref(s);
+
+        return 0;
+}
+
+static void test_pidfd(void) {
+        sd_event_source *s = NULL, *t = NULL;
+        sd_event *e = NULL;
+        int pidfd;
+        pid_t pid, pid2;
+
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGCHLD, -1) >= 0);
+
+        pid = fork();
+        if (pid == 0)
+                /* child */
+                _exit(66);
+
+        assert_se(pid > 1);
+
+        pidfd = pidfd_open(pid, 0);
+        if (pidfd < 0) {
+                /* No pidfd_open() supported or blocked? */
+                assert_se(ERRNO_IS_NOT_SUPPORTED(errno) || ERRNO_IS_PRIVILEGE(errno));
+                (void) wait_for_terminate(pid, NULL);
+                return;
+        }
+
+        pid2 = fork();
+        if (pid2 == 0)
+                freeze();
+
+        assert_se(pid > 2);
+
+        assert_se(sd_event_default(&e) >= 0);
+        assert_se(sd_event_add_child_pidfd(e, &s, pidfd, WEXITED, pidfd_handler, INT_TO_PTR('p')) >= 0);
+        assert_se(sd_event_source_set_child_pidfd_own(s, true) >= 0);
+
+        /* This one should never trigger, since our second child lives forever */
+        assert_se(sd_event_add_child(e, &t, pid2, WEXITED, pidfd_handler, INT_TO_PTR('q')) >= 0);
+        assert_se(sd_event_source_set_child_process_own(t, true) >= 0);
+
+        assert_se(sd_event_loop(e) >= 0);
+
+        /* Child should still be alive */
+        assert_se(kill(pid2, 0) >= 0);
+
+        t = sd_event_source_unref(t);
+
+        /* Child should now be dead, since we dropped the ref */
+        assert_se(kill(pid2, 0) < 0 && errno == ESRCH);
+
+        sd_event_unref(e);
+}
+
+int main(int argc, char *argv[]) {
+        test_setup_logging(LOG_INFO);
+
+        test_basic(true);   /* test with pidfd */
+        test_basic(false);  /* test without pidfd */
+
+        test_sd_event_now();
+        test_rtqueue();
+
+        test_inotify(100); /* should work without overflow */
+        test_inotify(33000); /* should trigger a q overflow */
+
+        test_pidfd();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-hwdb/hwdb-internal.h b/src/libsystemd/sd-hwdb/hwdb-internal.h
new file mode 100644
index 0000000..5c20688
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/hwdb-internal.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdint.h>
+
+#include "sparse-endian.h"
+
+#define HWDB_SIG { 'K', 'S', 'L', 'P', 'H', 'H', 'R', 'H' }
+
+/* on-disk trie objects */
+struct trie_header_f {
+        uint8_t signature[8];
+
+        /* version of tool which created the file */
+        le64_t tool_version;
+        le64_t file_size;
+
+        /* size of structures to allow them to grow */
+        le64_t header_size;
+        le64_t node_size;
+        le64_t child_entry_size;
+        le64_t value_entry_size;
+
+        /* offset of the root trie node */
+        le64_t nodes_root_off;
+
+        /* size of the nodes and string section */
+        le64_t nodes_len;
+        le64_t strings_len;
+} _packed_;
+
+struct trie_node_f {
+        /* prefix of lookup string, shared by all children  */
+        le64_t prefix_off;
+        /* size of children entry array appended to the node */
+        uint8_t children_count;
+        uint8_t padding[7];
+        /* size of value entry array appended to the node */
+        le64_t values_count;
+} _packed_;
+
+/* array of child entries, follows directly the node record */
+struct trie_child_entry_f {
+        /* index of the child node */
+        uint8_t c;
+        uint8_t padding[7];
+        /* offset of the child node */
+        le64_t child_off;
+} _packed_;
+
+/* array of value entries, follows directly the node record/child array */
+struct trie_value_entry_f {
+        le64_t key_off;
+        le64_t value_off;
+} _packed_;
+
+/* v2 extends v1 with filename and line-number */
+struct trie_value_entry2_f {
+        le64_t key_off;
+        le64_t value_off;
+        le64_t filename_off;
+        le32_t line_number;
+        le16_t file_priority;
+        le16_t padding;
+} _packed_;
diff --git a/src/libsystemd/sd-hwdb/hwdb-util.c b/src/libsystemd/sd-hwdb/hwdb-util.c
new file mode 100644
index 0000000..4c94ba9
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/hwdb-util.c
@@ -0,0 +1,668 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <sys/stat.h>
+
+#include "alloc-util.h"
+#include "conf-files.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hwdb-internal.h"
+#include "hwdb-util.h"
+#include "label.h"
+#include "mkdir.h"
+#include "path-util.h"
+#include "sort-util.h"
+#include "strbuf.h"
+#include "string-util.h"
+#include "strv.h"
+#include "tmpfile-util.h"
+
+static const char *default_hwdb_bin_dir = "/etc/udev";
+static const char * const conf_file_dirs[] = {
+        "/etc/udev/hwdb.d",
+        UDEVLIBEXECDIR "/hwdb.d",
+        NULL
+};
+
+/*
+ * Generic udev properties, key-value database based on modalias strings.
+ * Uses a Patricia/radix trie to index all matches for efficient lookup.
+ */
+
+/* in-memory trie objects */
+struct trie {
+        struct trie_node *root;
+        struct strbuf *strings;
+
+        size_t nodes_count;
+        size_t children_count;
+        size_t values_count;
+};
+
+struct trie_node {
+        /* prefix, common part for all children of this node */
+        size_t prefix_off;
+
+        /* sorted array of pointers to children nodes */
+        struct trie_child_entry *children;
+        uint8_t children_count;
+
+        /* sorted array of key-value pairs */
+        struct trie_value_entry *values;
+        size_t values_count;
+};
+
+/* children array item with char (0-255) index */
+struct trie_child_entry {
+        uint8_t c;
+        struct trie_node *child;
+};
+
+/* value array item with key-value pairs */
+struct trie_value_entry {
+        size_t key_off;
+        size_t value_off;
+        size_t filename_off;
+        uint32_t line_number;
+        uint16_t file_priority;
+};
+
+static int trie_children_cmp(const struct trie_child_entry *a, const struct trie_child_entry *b) {
+        return CMP(a->c, b->c);
+}
+
+static int node_add_child(struct trie *trie, struct trie_node *node, struct trie_node *node_child, uint8_t c) {
+        struct trie_child_entry *child;
+
+        /* extend array, add new entry, sort for bisection */
+        child = reallocarray(node->children, node->children_count + 1, sizeof(struct trie_child_entry));
+        if (!child)
+                return -ENOMEM;
+
+        node->children = child;
+        trie->children_count++;
+        node->children[node->children_count].c = c;
+        node->children[node->children_count].child = node_child;
+        node->children_count++;
+        typesafe_qsort(node->children, node->children_count, trie_children_cmp);
+        trie->nodes_count++;
+
+        return 0;
+}
+
+static struct trie_node *node_lookup(const struct trie_node *node, uint8_t c) {
+        struct trie_child_entry *child;
+        struct trie_child_entry search;
+
+        search.c = c;
+        child = typesafe_bsearch(&search, node->children, node->children_count, trie_children_cmp);
+        if (child)
+                return child->child;
+        return NULL;
+}
+
+static void trie_node_cleanup(struct trie_node *node) {
+        if (!node)
+                return;
+
+        for (size_t i = 0; i < node->children_count; i++)
+                trie_node_cleanup(node->children[i].child);
+        free(node->children);
+        free(node->values);
+        free(node);
+}
+
+static void trie_free(struct trie *trie) {
+        if (!trie)
+                return;
+
+        trie_node_cleanup(trie->root);
+        strbuf_cleanup(trie->strings);
+        free(trie);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct trie*, trie_free);
+
+static int trie_values_cmp(const struct trie_value_entry *a, const struct trie_value_entry *b, struct trie *trie) {
+        return strcmp(trie->strings->buf + a->key_off,
+                      trie->strings->buf + b->key_off);
+}
+
+static int trie_node_add_value(struct trie *trie, struct trie_node *node,
+                               const char *key, const char *value,
+                               const char *filename, uint16_t file_priority, uint32_t line_number, bool compat) {
+        ssize_t k, v, fn = 0;
+        struct trie_value_entry *val;
+
+        k = strbuf_add_string(trie->strings, key, strlen(key));
+        if (k < 0)
+                return k;
+        v = strbuf_add_string(trie->strings, value, strlen(value));
+        if (v < 0)
+                return v;
+
+        if (!compat) {
+                fn = strbuf_add_string(trie->strings, filename, strlen(filename));
+                if (fn < 0)
+                        return fn;
+        }
+
+        if (node->values_count) {
+                struct trie_value_entry search = {
+                        .key_off = k,
+                        .value_off = v,
+                };
+
+                val = typesafe_bsearch_r(&search, node->values, node->values_count, trie_values_cmp, trie);
+                if (val) {
+                        /* At this point we have 2 identical properties on the same match-string.
+                         * Since we process files in order, we just replace the previous value. */
+                        val->value_off = v;
+                        val->filename_off = fn;
+                        val->file_priority = file_priority;
+                        val->line_number = line_number;
+                        return 0;
+                }
+        }
+
+        /* extend array, add new entry, sort for bisection */
+        val = reallocarray(node->values, node->values_count + 1, sizeof(struct trie_value_entry));
+        if (!val)
+                return -ENOMEM;
+        trie->values_count++;
+        node->values = val;
+        node->values[node->values_count] = (struct trie_value_entry) {
+                .key_off = k,
+                .value_off = v,
+                .filename_off = fn,
+                .file_priority = file_priority,
+                .line_number = line_number,
+        };
+        node->values_count++;
+        typesafe_qsort_r(node->values, node->values_count, trie_values_cmp, trie);
+        return 0;
+}
+
+static int trie_insert(struct trie *trie, struct trie_node *node, const char *search,
+                       const char *key, const char *value,
+                       const char *filename, uint16_t file_priority, uint32_t line_number, bool compat) {
+        int r = 0;
+
+        for (size_t i = 0;; i++) {
+                size_t p;
+                uint8_t c;
+                struct trie_node *child;
+
+                for (p = 0; (c = trie->strings->buf[node->prefix_off + p]); p++) {
+                        _cleanup_free_ struct trie_node *new_child = NULL;
+                        _cleanup_free_ char *s = NULL;
+                        ssize_t off;
+
+                        if (c == search[i + p])
+                                continue;
+
+                        /* split node */
+                        new_child = new(struct trie_node, 1);
+                        if (!new_child)
+                                return -ENOMEM;
+
+                        /* move values from parent to child */
+                        *new_child = (struct trie_node) {
+                                .prefix_off = node->prefix_off + p+1,
+                                .children = node->children,
+                                .children_count = node->children_count,
+                                .values = node->values,
+                                .values_count = node->values_count,
+                        };
+
+                        /* update parent; use strdup() because the source gets realloc()d */
+                        s = strndup(trie->strings->buf + node->prefix_off, p);
+                        if (!s)
+                                return -ENOMEM;
+
+                        off = strbuf_add_string(trie->strings, s, p);
+                        if (off < 0)
+                                return off;
+
+                        *node = (struct trie_node) {
+                                .prefix_off = off,
+                        };
+                        r = node_add_child(trie, node, new_child, c);
+                        if (r < 0)
+                                return r;
+
+                        new_child = NULL; /* avoid cleanup */
+                        break;
+                }
+                i += p;
+
+                c = search[i];
+                if (c == '\0')
+                        return trie_node_add_value(trie, node, key, value, filename, file_priority, line_number, compat);
+
+                child = node_lookup(node, c);
+                if (!child) {
+                        _cleanup_free_ struct trie_node *new_child = NULL;
+                        ssize_t off;
+
+                        /* new child */
+                        new_child = new(struct trie_node, 1);
+                        if (!new_child)
+                                return -ENOMEM;
+
+                        off = strbuf_add_string(trie->strings, search + i+1, strlen(search + i+1));
+                        if (off < 0)
+                                return off;
+
+                        *new_child = (struct trie_node) {
+                                .prefix_off = off,
+                        };
+
+                        r = node_add_child(trie, node, new_child, c);
+                        if (r < 0)
+                                return r;
+
+                        child = TAKE_PTR(new_child);
+                        return trie_node_add_value(trie, child, key, value, filename, file_priority, line_number, compat);
+                }
+
+                node = child;
+        }
+}
+
+struct trie_f {
+        FILE *f;
+        struct trie *trie;
+        uint64_t strings_off;
+
+        uint64_t nodes_count;
+        uint64_t children_count;
+        uint64_t values_count;
+};
+
+/* calculate the storage space for the nodes, children arrays, value arrays */
+static void trie_store_nodes_size(struct trie_f *trie, struct trie_node *node, bool compat) {
+        for (uint64_t i = 0; i < node->children_count; i++)
+                trie_store_nodes_size(trie, node->children[i].child, compat);
+
+        trie->strings_off += sizeof(struct trie_node_f);
+        for (uint64_t i = 0; i < node->children_count; i++)
+                trie->strings_off += sizeof(struct trie_child_entry_f);
+        for (uint64_t i = 0; i < node->values_count; i++)
+                trie->strings_off += compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f);
+}
+
+static int64_t trie_store_nodes(struct trie_f *trie, struct trie_node *node, bool compat) {
+        struct trie_node_f n = {
+                .prefix_off = htole64(trie->strings_off + node->prefix_off),
+                .children_count = node->children_count,
+                .values_count = htole64(node->values_count),
+        };
+        _cleanup_free_ struct trie_child_entry_f *children = NULL;
+        int64_t node_off;
+
+        if (node->children_count) {
+                children = new(struct trie_child_entry_f, node->children_count);
+                if (!children)
+                        return -ENOMEM;
+        }
+
+        /* post-order recursion */
+        for (uint64_t i = 0; i < node->children_count; i++) {
+                int64_t child_off;
+
+                child_off = trie_store_nodes(trie, node->children[i].child, compat);
+                if (child_off < 0)
+                        return child_off;
+
+                children[i] = (struct trie_child_entry_f) {
+                        .c = node->children[i].c,
+                        .child_off = htole64(child_off),
+                };
+        }
+
+        /* write node */
+        node_off = ftello(trie->f);
+        fwrite(&n, sizeof(struct trie_node_f), 1, trie->f);
+        trie->nodes_count++;
+
+        /* append children array */
+        if (node->children_count) {
+                fwrite(children, sizeof(struct trie_child_entry_f), node->children_count, trie->f);
+                trie->children_count += node->children_count;
+        }
+
+        /* append values array */
+        for (uint64_t i = 0; i < node->values_count; i++) {
+                struct trie_value_entry2_f v = {
+                        .key_off = htole64(trie->strings_off + node->values[i].key_off),
+                        .value_off = htole64(trie->strings_off + node->values[i].value_off),
+                        .filename_off = htole64(trie->strings_off + node->values[i].filename_off),
+                        .line_number = htole32(node->values[i].line_number),
+                        .file_priority = htole16(node->values[i].file_priority),
+                };
+
+                fwrite(&v, compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f), 1, trie->f);
+        }
+        trie->values_count += node->values_count;
+
+        return node_off;
+}
+
+static int trie_store(struct trie *trie, const char *filename, bool compat) {
+        struct trie_f t = {
+                .trie = trie,
+        };
+        _cleanup_free_ char *filename_tmp = NULL;
+        int64_t pos;
+        int64_t root_off;
+        int64_t size;
+        struct trie_header_f h = {
+                .signature = HWDB_SIG,
+                .tool_version = htole64(PROJECT_VERSION),
+                .header_size = htole64(sizeof(struct trie_header_f)),
+                .node_size = htole64(sizeof(struct trie_node_f)),
+                .child_entry_size = htole64(sizeof(struct trie_child_entry_f)),
+                .value_entry_size = htole64(compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f)),
+        };
+        int r;
+
+        /* calculate size of header, nodes, children entries, value entries */
+        t.strings_off = sizeof(struct trie_header_f);
+        trie_store_nodes_size(&t, trie->root, compat);
+
+        r = fopen_temporary(filename, &t.f, &filename_tmp);
+        if (r < 0)
+                return r;
+        fchmod(fileno(t.f), 0444);
+
+        /* write nodes */
+        if (fseeko(t.f, sizeof(struct trie_header_f), SEEK_SET) < 0)
+                goto error_fclose;
+
+        root_off = trie_store_nodes(&t, trie->root, compat);
+        h.nodes_root_off = htole64(root_off);
+        pos = ftello(t.f);
+        h.nodes_len = htole64(pos - sizeof(struct trie_header_f));
+
+        /* write string buffer */
+        fwrite(trie->strings->buf, trie->strings->len, 1, t.f);
+        h.strings_len = htole64(trie->strings->len);
+
+        /* write header */
+        size = ftello(t.f);
+        h.file_size = htole64(size);
+        if (fseeko(t.f, 0, SEEK_SET) < 0)
+                goto error_fclose;
+        fwrite(&h, sizeof(struct trie_header_f), 1, t.f);
+
+        if (ferror(t.f))
+                goto error_fclose;
+        if (fflush(t.f) < 0)
+                goto error_fclose;
+        if (fsync(fileno(t.f)) < 0)
+                goto error_fclose;
+        if (rename(filename_tmp, filename) < 0)
+                goto error_fclose;
+
+        /* write succeeded */
+        fclose(t.f);
+
+        log_debug("=== trie on-disk ===");
+        log_debug("size:             %8"PRIi64" bytes", size);
+        log_debug("header:           %8zu bytes", sizeof(struct trie_header_f));
+        log_debug("nodes:            %8"PRIu64" bytes (%8"PRIu64")",
+                  t.nodes_count * sizeof(struct trie_node_f), t.nodes_count);
+        log_debug("child pointers:   %8"PRIu64" bytes (%8"PRIu64")",
+                  t.children_count * sizeof(struct trie_child_entry_f), t.children_count);
+        log_debug("value pointers:   %8"PRIu64" bytes (%8"PRIu64")",
+                  t.values_count * (compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f)), t.values_count);
+        log_debug("string store:     %8zu bytes", trie->strings->len);
+        log_debug("strings start:    %8"PRIu64, t.strings_off);
+        return 0;
+
+ error_fclose:
+        r = -errno;
+        fclose(t.f);
+        (void) unlink(filename_tmp);
+        return r;
+}
+
+static int insert_data(struct trie *trie, char **match_list, char *line, const char *filename,
+                       uint16_t file_priority, uint32_t line_number, bool compat) {
+        char *value, **entry;
+
+        assert(line[0] == ' ');
+
+        value = strchr(line, '=');
+        if (!value)
+                return log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
+                                  "Key-value pair expected but got \"%s\", ignoring.", line);
+
+        value[0] = '\0';
+        value++;
+
+        /* Replace multiple leading spaces by a single space */
+        while (isblank(line[0]) && isblank(line[1]))
+                line++;
+
+        if (isempty(line + 1))
+                return log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
+                                  "Empty key in \"%s=%s\", ignoring.",
+                                  line, value);
+
+        STRV_FOREACH(entry, match_list)
+                trie_insert(trie, trie->root, *entry, line, value, filename, file_priority, line_number, compat);
+
+        return 0;
+}
+
+static int import_file(struct trie *trie, const char *filename, uint16_t file_priority, bool compat) {
+        enum {
+                HW_NONE,
+                HW_MATCH,
+                HW_DATA,
+        } state = HW_NONE;
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_strv_free_ char **match_list = NULL;
+        uint32_t line_number = 0;
+        int r, err;
+
+        f = fopen(filename, "re");
+        if (!f)
+                return -errno;
+
+        for (;;) {
+                _cleanup_free_ char *line = NULL;
+                size_t len;
+                char *pos;
+
+                r = read_line_full(f, LONG_LINE_MAX, READ_LINE_NOT_A_TTY, &line);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                line_number ++;
+
+                /* comment line */
+                if (line[0] == '#')
+                        continue;
+
+                /* strip trailing comment */
+                pos = strchr(line, '#');
+                if (pos)
+                        pos[0] = '\0';
+
+                /* strip trailing whitespace */
+                len = strlen(line);
+                while (len > 0 && isspace(line[len-1]))
+                        len--;
+                line[len] = '\0';
+
+                switch (state) {
+                case HW_NONE:
+                        if (len == 0)
+                                break;
+
+                        if (line[0] == ' ') {
+                                r = log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
+                                               "Match expected but got indented property \"%s\", ignoring line.", line);
+                                break;
+                        }
+
+                        /* start of record, first match */
+                        state = HW_MATCH;
+
+                        err = strv_extend(&match_list, line);
+                        if (err < 0)
+                                return err;
+
+                        break;
+
+                case HW_MATCH:
+                        if (len == 0) {
+                                r = log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
+                                               "Property expected, ignoring record with no properties.");
+                                state = HW_NONE;
+                                match_list = strv_free(match_list);
+                                break;
+                        }
+
+                        if (line[0] != ' ') {
+                                /* another match */
+                                err = strv_extend(&match_list, line);
+                                if (err < 0)
+                                        return err;
+
+                                break;
+                        }
+
+                        /* first data */
+                        state = HW_DATA;
+                        err = insert_data(trie, match_list, line, filename, file_priority, line_number, compat);
+                        if (err < 0)
+                                r = err;
+                        break;
+
+                case HW_DATA:
+                        if (len == 0) {
+                                /* end of record */
+                                state = HW_NONE;
+                                match_list = strv_free(match_list);
+                                break;
+                        }
+
+                        if (line[0] != ' ') {
+                                r = log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
+                                               "Property or empty line expected, got \"%s\", ignoring record.", line);
+                                state = HW_NONE;
+                                match_list = strv_free(match_list);
+                                break;
+                        }
+
+                        err = insert_data(trie, match_list, line, filename, file_priority, line_number, compat);
+                        if (err < 0)
+                                r = err;
+                        break;
+                };
+        }
+
+        if (state == HW_MATCH)
+                log_syntax(NULL, LOG_WARNING, filename, line_number, 0,
+                           "Property expected, ignoring record with no properties.");
+
+        return r;
+}
+
+int hwdb_update(const char *root, const char *hwdb_bin_dir, bool strict, bool compat) {
+        _cleanup_free_ char *hwdb_bin = NULL;
+        _cleanup_(trie_freep) struct trie *trie = NULL;
+        _cleanup_strv_free_ char **files = NULL;
+        char **f;
+        uint16_t file_priority = 1;
+        int r = 0, err;
+
+        /* The argument 'compat' controls the format version of database. If false, then hwdb.bin will be created with
+         * additional information such that priority, line number, and filename of database source. If true, then hwdb.bin
+         * will be created without the information. systemd-hwdb command should set the argument false, and 'udevadm hwdb'
+         * command should set it true. */
+
+        trie = new0(struct trie, 1);
+        if (!trie)
+                return -ENOMEM;
+
+        /* string store */
+        trie->strings = strbuf_new();
+        if (!trie->strings)
+                return -ENOMEM;
+
+        /* index */
+        trie->root = new0(struct trie_node, 1);
+        if (!trie->root)
+                return -ENOMEM;
+
+        trie->nodes_count++;
+
+        err = conf_files_list_strv(&files, ".hwdb", root, 0, conf_file_dirs);
+        if (err < 0)
+                return log_error_errno(err, "Failed to enumerate hwdb files: %m");
+
+        STRV_FOREACH(f, files) {
+                log_debug("Reading file \"%s\"", *f);
+                err = import_file(trie, *f, file_priority++, compat);
+                if (err < 0 && strict)
+                        r = err;
+        }
+
+        strbuf_complete(trie->strings);
+
+        log_debug("=== trie in-memory ===");
+        log_debug("nodes:            %8zu bytes (%8zu)",
+                  trie->nodes_count * sizeof(struct trie_node), trie->nodes_count);
+        log_debug("children arrays:  %8zu bytes (%8zu)",
+                  trie->children_count * sizeof(struct trie_child_entry), trie->children_count);
+        log_debug("values arrays:    %8zu bytes (%8zu)",
+                  trie->values_count * sizeof(struct trie_value_entry), trie->values_count);
+        log_debug("strings:          %8zu bytes",
+                  trie->strings->len);
+        log_debug("strings incoming: %8zu bytes (%8zu)",
+                  trie->strings->in_len, trie->strings->in_count);
+        log_debug("strings dedup'ed: %8zu bytes (%8zu)",
+                  trie->strings->dedup_len, trie->strings->dedup_count);
+
+        hwdb_bin = path_join(root, hwdb_bin_dir ?: default_hwdb_bin_dir, "hwdb.bin");
+        if (!hwdb_bin)
+                return -ENOMEM;
+
+        mkdir_parents_label(hwdb_bin, 0755);
+        err = trie_store(trie, hwdb_bin, compat);
+        if (err < 0)
+                return log_error_errno(err, "Failed to write database %s: %m", hwdb_bin);
+
+        err = label_fix(hwdb_bin, 0);
+        if (err < 0)
+                return err;
+
+        return r;
+}
+
+int hwdb_query(const char *modalias) {
+        _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb = NULL;
+        const char *key, *value;
+        int r;
+
+        assert(modalias);
+
+        r = sd_hwdb_new(&hwdb);
+        if (r < 0)
+                return r;
+
+        SD_HWDB_FOREACH_PROPERTY(hwdb, modalias, key, value)
+                printf("%s=%s\n", key, value);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-hwdb/hwdb-util.h b/src/libsystemd/sd-hwdb/hwdb-util.h
new file mode 100644
index 0000000..5afde74
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/hwdb-util.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+#include "sd-hwdb.h"
+
+bool hwdb_validate(sd_hwdb *hwdb);
+int hwdb_update(const char *root, const char *hwdb_bin_dir, bool strict, bool compat);
+int hwdb_query(const char *modalias);
diff --git a/src/libsystemd/sd-hwdb/sd-hwdb.c b/src/libsystemd/sd-hwdb/sd-hwdb.c
new file mode 100644
index 0000000..cb3c77c
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/sd-hwdb.c
@@ -0,0 +1,466 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2008 Alan Jenkins <alan.christopher.jenkins@googlemail.com>
+***/
+
+#include <errno.h>
+#include <fnmatch.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include "sd-hwdb.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "hashmap.h"
+#include "hwdb-internal.h"
+#include "hwdb-util.h"
+#include "nulstr-util.h"
+#include "string-util.h"
+#include "time-util.h"
+
+struct sd_hwdb {
+        unsigned n_ref;
+
+        FILE *f;
+        struct stat st;
+        union {
+                struct trie_header_f *head;
+                const char *map;
+        };
+
+        OrderedHashmap *properties;
+        Iterator properties_iterator;
+        bool properties_modified;
+};
+
+struct linebuf {
+        char bytes[LINE_MAX];
+        size_t size;
+        size_t len;
+};
+
+static void linebuf_init(struct linebuf *buf) {
+        buf->size = 0;
+        buf->len = 0;
+}
+
+static const char *linebuf_get(struct linebuf *buf) {
+        if (buf->len + 1 >= sizeof(buf->bytes))
+                return NULL;
+        buf->bytes[buf->len] = '\0';
+        return buf->bytes;
+}
+
+static bool linebuf_add(struct linebuf *buf, const char *s, size_t len) {
+        if (buf->len + len >= sizeof(buf->bytes))
+                return false;
+        memcpy(buf->bytes + buf->len, s, len);
+        buf->len += len;
+        return true;
+}
+
+static bool linebuf_add_char(struct linebuf *buf, char c) {
+        if (buf->len + 1 >= sizeof(buf->bytes))
+                return false;
+        buf->bytes[buf->len++] = c;
+        return true;
+}
+
+static void linebuf_rem(struct linebuf *buf, size_t count) {
+        assert(buf->len >= count);
+        buf->len -= count;
+}
+
+static void linebuf_rem_char(struct linebuf *buf) {
+        linebuf_rem(buf, 1);
+}
+
+static const struct trie_child_entry_f *trie_node_child(sd_hwdb *hwdb, const struct trie_node_f *node, size_t idx) {
+        const char *base = (const char *)node;
+
+        base += le64toh(hwdb->head->node_size);
+        base += idx * le64toh(hwdb->head->child_entry_size);
+        return (const struct trie_child_entry_f *)base;
+}
+
+static const struct trie_value_entry_f *trie_node_value(sd_hwdb *hwdb, const struct trie_node_f *node, size_t idx) {
+        const char *base = (const char *)node;
+
+        base += le64toh(hwdb->head->node_size);
+        base += node->children_count * le64toh(hwdb->head->child_entry_size);
+        base += idx * le64toh(hwdb->head->value_entry_size);
+        return (const struct trie_value_entry_f *)base;
+}
+
+static const struct trie_node_f *trie_node_from_off(sd_hwdb *hwdb, le64_t off) {
+        return (const struct trie_node_f *)(hwdb->map + le64toh(off));
+}
+
+static const char *trie_string(sd_hwdb *hwdb, le64_t off) {
+        return hwdb->map + le64toh(off);
+}
+
+static int trie_children_cmp_f(const void *v1, const void *v2) {
+        const struct trie_child_entry_f *n1 = v1;
+        const struct trie_child_entry_f *n2 = v2;
+
+        return n1->c - n2->c;
+}
+
+static const struct trie_node_f *node_lookup_f(sd_hwdb *hwdb, const struct trie_node_f *node, uint8_t c) {
+        struct trie_child_entry_f *child;
+        struct trie_child_entry_f search;
+
+        search.c = c;
+        child = bsearch(&search, (const char *)node + le64toh(hwdb->head->node_size), node->children_count,
+                        le64toh(hwdb->head->child_entry_size), trie_children_cmp_f);
+        if (child)
+                return trie_node_from_off(hwdb, child->child_off);
+        return NULL;
+}
+
+static int hwdb_add_property(sd_hwdb *hwdb, const struct trie_value_entry_f *entry) {
+        const char *key;
+        int r;
+
+        assert(hwdb);
+
+        key = trie_string(hwdb, entry->key_off);
+
+        /*
+         * Silently ignore all properties which do not start with a
+         * space; future extensions might use additional prefixes.
+         */
+        if (key[0] != ' ')
+                return 0;
+
+        key++;
+
+        if (le64toh(hwdb->head->value_entry_size) >= sizeof(struct trie_value_entry2_f)) {
+                const struct trie_value_entry2_f *old, *entry2;
+
+                entry2 = (const struct trie_value_entry2_f *)entry;
+                old = ordered_hashmap_get(hwdb->properties, key);
+                if (old) {
+                        /* On duplicates, we order by filename priority and line-number.
+                         *
+                         * v2 of the format had 64 bits for the line number.
+                         * v3 reuses top 32 bits of line_number to store the priority.
+                         * We check the top bits — if they are zero we have v2 format.
+                         * This means that v2 clients will print wrong line numbers with
+                         * v3 data.
+                         *
+                         * For v3 data: we compare the priority (of the source file)
+                         * and the line number.
+                         *
+                         * For v2 data: we rely on the fact that the filenames in the hwdb
+                         * are added in the order of priority (higher later), because they
+                         * are *processed* in the order of priority. So we compare the
+                         * indices to determine which file had higher priority. Comparing
+                         * the strings alphabetically would be useless, because those are
+                         * full paths, and e.g. /usr/lib would sort after /etc, even
+                         * though it has lower priority. This is not reliable because of
+                         * suffix compression, but should work for the most common case of
+                         * /usr/lib/udev/hwbd.d and /etc/udev/hwdb.d, and is better than
+                         * not doing the comparison at all.
+                         */
+                        bool lower;
+
+                        if (entry2->file_priority == 0)
+                                lower = entry2->filename_off < old->filename_off ||
+                                        (entry2->filename_off == old->filename_off && entry2->line_number < old->line_number);
+                        else
+                                lower = entry2->file_priority < old->file_priority ||
+                                        (entry2->file_priority == old->file_priority && entry2->line_number < old->line_number);
+                        if (lower)
+                                return 0;
+                }
+        }
+
+        r = ordered_hashmap_ensure_allocated(&hwdb->properties, &string_hash_ops);
+        if (r < 0)
+                return r;
+
+        r = ordered_hashmap_replace(hwdb->properties, key, (void *)entry);
+        if (r < 0)
+                return r;
+
+        hwdb->properties_modified = true;
+
+        return 0;
+}
+
+static int trie_fnmatch_f(sd_hwdb *hwdb, const struct trie_node_f *node, size_t p,
+                          struct linebuf *buf, const char *search) {
+        size_t len;
+        size_t i;
+        const char *prefix;
+        int err;
+
+        prefix = trie_string(hwdb, node->prefix_off);
+        len = strlen(prefix + p);
+        linebuf_add(buf, prefix + p, len);
+
+        for (i = 0; i < node->children_count; i++) {
+                const struct trie_child_entry_f *child = trie_node_child(hwdb, node, i);
+
+                linebuf_add_char(buf, child->c);
+                err = trie_fnmatch_f(hwdb, trie_node_from_off(hwdb, child->child_off), 0, buf, search);
+                if (err < 0)
+                        return err;
+                linebuf_rem_char(buf);
+        }
+
+        if (le64toh(node->values_count) && fnmatch(linebuf_get(buf), search, 0) == 0)
+                for (i = 0; i < le64toh(node->values_count); i++) {
+                        err = hwdb_add_property(hwdb, trie_node_value(hwdb, node, i));
+                        if (err < 0)
+                                return err;
+                }
+
+        linebuf_rem(buf, len);
+        return 0;
+}
+
+static int trie_search_f(sd_hwdb *hwdb, const char *search) {
+        struct linebuf buf;
+        const struct trie_node_f *node;
+        size_t i = 0;
+        int err;
+
+        linebuf_init(&buf);
+
+        node = trie_node_from_off(hwdb, hwdb->head->nodes_root_off);
+        while (node) {
+                const struct trie_node_f *child;
+                size_t p = 0;
+
+                if (node->prefix_off) {
+                        char c;
+
+                        for (; (c = trie_string(hwdb, node->prefix_off)[p]); p++) {
+                                if (IN_SET(c, '*', '?', '['))
+                                        return trie_fnmatch_f(hwdb, node, p, &buf, search + i + p);
+                                if (c != search[i + p])
+                                        return 0;
+                        }
+                        i += p;
+                }
+
+                child = node_lookup_f(hwdb, node, '*');
+                if (child) {
+                        linebuf_add_char(&buf, '*');
+                        err = trie_fnmatch_f(hwdb, child, 0, &buf, search + i);
+                        if (err < 0)
+                                return err;
+                        linebuf_rem_char(&buf);
+                }
+
+                child = node_lookup_f(hwdb, node, '?');
+                if (child) {
+                        linebuf_add_char(&buf, '?');
+                        err = trie_fnmatch_f(hwdb, child, 0, &buf, search + i);
+                        if (err < 0)
+                                return err;
+                        linebuf_rem_char(&buf);
+                }
+
+                child = node_lookup_f(hwdb, node, '[');
+                if (child) {
+                        linebuf_add_char(&buf, '[');
+                        err = trie_fnmatch_f(hwdb, child, 0, &buf, search + i);
+                        if (err < 0)
+                                return err;
+                        linebuf_rem_char(&buf);
+                }
+
+                if (search[i] == '\0') {
+                        size_t n;
+
+                        for (n = 0; n < le64toh(node->values_count); n++) {
+                                err = hwdb_add_property(hwdb, trie_node_value(hwdb, node, n));
+                                if (err < 0)
+                                        return err;
+                        }
+                        return 0;
+                }
+
+                child = node_lookup_f(hwdb, node, search[i]);
+                node = child;
+                i++;
+        }
+        return 0;
+}
+
+static const char hwdb_bin_paths[] =
+        "/etc/systemd/hwdb/hwdb.bin\0"
+        "/etc/udev/hwdb.bin\0"
+        "/usr/lib/systemd/hwdb/hwdb.bin\0"
+#if HAVE_SPLIT_USR
+        "/lib/systemd/hwdb/hwdb.bin\0"
+#endif
+        UDEVLIBEXECDIR "/hwdb.bin\0";
+
+_public_ int sd_hwdb_new(sd_hwdb **ret) {
+        _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb = NULL;
+        const char *hwdb_bin_path;
+        const char sig[] = HWDB_SIG;
+
+        assert_return(ret, -EINVAL);
+
+        hwdb = new0(sd_hwdb, 1);
+        if (!hwdb)
+                return -ENOMEM;
+
+        hwdb->n_ref = 1;
+
+        /* find hwdb.bin in hwdb_bin_paths */
+        NULSTR_FOREACH(hwdb_bin_path, hwdb_bin_paths) {
+                log_debug("Trying to open \"%s\"...", hwdb_bin_path);
+                hwdb->f = fopen(hwdb_bin_path, "re");
+                if (hwdb->f)
+                        break;
+                if (errno != ENOENT)
+                        return log_debug_errno(errno, "Failed to open %s: %m", hwdb_bin_path);
+        }
+
+        if (!hwdb->f)
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOENT),
+                                       "hwdb.bin does not exist, please run 'systemd-hwdb update'");
+
+        if (fstat(fileno(hwdb->f), &hwdb->st) < 0)
+                return log_debug_errno(errno, "Failed to stat %s: %m", hwdb_bin_path);
+        if (hwdb->st.st_size < (off_t) offsetof(struct trie_header_f, strings_len) + 8)
+                return log_debug_errno(SYNTHETIC_ERRNO(EIO),
+                                       "File %s is too short: %m", hwdb_bin_path);
+
+        hwdb->map = mmap(0, hwdb->st.st_size, PROT_READ, MAP_SHARED, fileno(hwdb->f), 0);
+        if (hwdb->map == MAP_FAILED)
+                return log_debug_errno(errno, "Failed to map %s: %m", hwdb_bin_path);
+
+        if (memcmp(hwdb->map, sig, sizeof(hwdb->head->signature)) != 0 ||
+            (size_t) hwdb->st.st_size != le64toh(hwdb->head->file_size))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Failed to recognize the format of %s",
+                                       hwdb_bin_path);
+
+        log_debug("=== trie on-disk ===");
+        log_debug("tool version:          %"PRIu64, le64toh(hwdb->head->tool_version));
+        log_debug("file size:        %8"PRIi64" bytes", hwdb->st.st_size);
+        log_debug("header size       %8"PRIu64" bytes", le64toh(hwdb->head->header_size));
+        log_debug("strings           %8"PRIu64" bytes", le64toh(hwdb->head->strings_len));
+        log_debug("nodes             %8"PRIu64" bytes", le64toh(hwdb->head->nodes_len));
+
+        *ret = TAKE_PTR(hwdb);
+
+        return 0;
+}
+
+static sd_hwdb *hwdb_free(sd_hwdb *hwdb) {
+        assert(hwdb);
+
+        if (hwdb->map)
+                munmap((void *)hwdb->map, hwdb->st.st_size);
+        safe_fclose(hwdb->f);
+        ordered_hashmap_free(hwdb->properties);
+        return mfree(hwdb);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_hwdb, sd_hwdb, hwdb_free)
+
+bool hwdb_validate(sd_hwdb *hwdb) {
+        bool found = false;
+        const char* p;
+        struct stat st;
+
+        if (!hwdb)
+                return false;
+        if (!hwdb->f)
+                return false;
+
+        /* if hwdb.bin doesn't exist anywhere, we need to update */
+        NULSTR_FOREACH(p, hwdb_bin_paths)
+                if (stat(p, &st) >= 0) {
+                        found = true;
+                        break;
+                }
+        if (!found)
+                return true;
+
+        if (timespec_load(&hwdb->st.st_mtim) != timespec_load(&st.st_mtim))
+                return true;
+        return false;
+}
+
+static int properties_prepare(sd_hwdb *hwdb, const char *modalias) {
+        assert(hwdb);
+        assert(modalias);
+
+        ordered_hashmap_clear(hwdb->properties);
+        hwdb->properties_modified = true;
+
+        return trie_search_f(hwdb, modalias);
+}
+
+_public_ int sd_hwdb_get(sd_hwdb *hwdb, const char *modalias, const char *key, const char **_value) {
+        const struct trie_value_entry_f *entry;
+        int r;
+
+        assert_return(hwdb, -EINVAL);
+        assert_return(hwdb->f, -EINVAL);
+        assert_return(modalias, -EINVAL);
+        assert_return(_value, -EINVAL);
+
+        r = properties_prepare(hwdb, modalias);
+        if (r < 0)
+                return r;
+
+        entry = ordered_hashmap_get(hwdb->properties, key);
+        if (!entry)
+                return -ENOENT;
+
+        *_value = trie_string(hwdb, entry->value_off);
+
+        return 0;
+}
+
+_public_ int sd_hwdb_seek(sd_hwdb *hwdb, const char *modalias) {
+        int r;
+
+        assert_return(hwdb, -EINVAL);
+        assert_return(hwdb->f, -EINVAL);
+        assert_return(modalias, -EINVAL);
+
+        r = properties_prepare(hwdb, modalias);
+        if (r < 0)
+                return r;
+
+        hwdb->properties_modified = false;
+        hwdb->properties_iterator = ITERATOR_FIRST;
+
+        return 0;
+}
+
+_public_ int sd_hwdb_enumerate(sd_hwdb *hwdb, const char **key, const char **value) {
+        const struct trie_value_entry_f *entry;
+        const void *k;
+
+        assert_return(hwdb, -EINVAL);
+        assert_return(key, -EINVAL);
+        assert_return(value, -EINVAL);
+
+        if (hwdb->properties_modified)
+                return -EAGAIN;
+
+        if (!ordered_hashmap_iterate(hwdb->properties, &hwdb->properties_iterator, (void **)&entry, &k))
+                return 0;
+
+        *key = k;
+        *value = trie_string(hwdb, entry->value_off);
+
+        return 1;
+}
diff --git a/src/libsystemd/sd-id128/id128-util.c b/src/libsystemd/sd-id128/id128-util.c
new file mode 100644
index 0000000..a3f6da6
--- /dev/null
+++ b/src/libsystemd/sd-id128/id128-util.c
@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "fd-util.h"
+#include "fs-util.h"
+#include "hexdecoct.h"
+#include "id128-util.h"
+#include "io-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+
+char *id128_to_uuid_string(sd_id128_t id, char s[static ID128_UUID_STRING_MAX]) {
+        unsigned n, k = 0;
+
+        assert(s);
+
+        /* Similar to sd_id128_to_string() but formats the result as UUID instead of plain hex chars */
+
+        for (n = 0; n < 16; n++) {
+
+                if (IN_SET(n, 4, 6, 8, 10))
+                        s[k++] = '-';
+
+                s[k++] = hexchar(id.bytes[n] >> 4);
+                s[k++] = hexchar(id.bytes[n] & 0xF);
+        }
+
+        assert(k == 36);
+
+        s[k] = 0;
+
+        return s;
+}
+
+bool id128_is_valid(const char *s) {
+        size_t i, l;
+
+        assert(s);
+
+        l = strlen(s);
+        if (l == 32) {
+
+                /* Plain formatted 128bit hex string */
+
+                for (i = 0; i < l; i++) {
+                        char c = s[i];
+
+                        if (!(c >= '0' && c <= '9') &&
+                            !(c >= 'a' && c <= 'z') &&
+                            !(c >= 'A' && c <= 'Z'))
+                                return false;
+                }
+
+        } else if (l == 36) {
+
+                /* Formatted UUID */
+
+                for (i = 0; i < l; i++) {
+                        char c = s[i];
+
+                        if (IN_SET(i, 8, 13, 18, 23)) {
+                                if (c != '-')
+                                        return false;
+                        } else {
+                                if (!(c >= '0' && c <= '9') &&
+                                    !(c >= 'a' && c <= 'z') &&
+                                    !(c >= 'A' && c <= 'Z'))
+                                        return false;
+                        }
+                }
+
+        } else
+                return false;
+
+        return true;
+}
+
+int id128_read_fd(int fd, Id128Format f, sd_id128_t *ret) {
+        char buffer[36 + 2];
+        ssize_t l;
+
+        assert(fd >= 0);
+        assert(f < _ID128_FORMAT_MAX);
+
+        /* Reads an 128bit ID from a file, which may either be in plain format (32 hex digits), or in UUID format, both
+         * optionally followed by a newline and nothing else. ID files should really be newline terminated, but if they
+         * aren't that's OK too, following the rule of "Be conservative in what you send, be liberal in what you
+         * accept". */
+
+        l = loop_read(fd, buffer, sizeof(buffer), false); /* we expect a short read of either 32/33 or 36/37 chars */
+        if (l < 0)
+                return (int) l;
+        if (l == 0) /* empty? */
+                return -ENOMEDIUM;
+
+        switch (l) {
+
+        case 13:
+        case 14:
+                /* Treat an "uninitialized" id file like an empty one */
+                return f == ID128_PLAIN_OR_UNINIT && strneq(buffer, "uninitialized\n", l) ? -ENOMEDIUM : -EINVAL;
+
+        case 33: /* plain UUID with trailing newline */
+                if (buffer[32] != '\n')
+                        return -EINVAL;
+
+                _fallthrough_;
+        case 32: /* plain UUID without trailing newline */
+                if (f == ID128_UUID)
+                        return -EINVAL;
+
+                buffer[32] = 0;
+                break;
+
+        case 37: /* RFC UUID with trailing newline */
+                if (buffer[36] != '\n')
+                        return -EINVAL;
+
+                _fallthrough_;
+        case 36: /* RFC UUID without trailing newline */
+                if (IN_SET(f, ID128_PLAIN, ID128_PLAIN_OR_UNINIT))
+                        return -EINVAL;
+
+                buffer[36] = 0;
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        return sd_id128_from_string(buffer, ret);
+}
+
+int id128_read(const char *p, Id128Format f, sd_id128_t *ret) {
+        _cleanup_close_ int fd = -1;
+
+        fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+        if (fd < 0)
+                return -errno;
+
+        return id128_read_fd(fd, f, ret);
+}
+
+int id128_write_fd(int fd, Id128Format f, sd_id128_t id, bool do_sync) {
+        char buffer[36 + 2];
+        size_t sz;
+        int r;
+
+        assert(fd >= 0);
+        assert(f < _ID128_FORMAT_MAX);
+
+        if (f != ID128_UUID) {
+                sd_id128_to_string(id, buffer);
+                buffer[32] = '\n';
+                sz = 33;
+        } else {
+                id128_to_uuid_string(id, buffer);
+                buffer[36] = '\n';
+                sz = 37;
+        }
+
+        r = loop_write(fd, buffer, sz, false);
+        if (r < 0)
+                return r;
+
+        if (do_sync) {
+                if (fsync(fd) < 0)
+                        return -errno;
+
+                r = fsync_directory_of_file(fd);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int id128_write(const char *p, Id128Format f, sd_id128_t id, bool do_sync) {
+        _cleanup_close_ int fd = -1;
+
+        fd = open(p, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY|O_TRUNC, 0444);
+        if (fd < 0)
+                return -errno;
+
+        return id128_write_fd(fd, f, id, do_sync);
+}
+
+void id128_hash_func(const sd_id128_t *p, struct siphash *state) {
+        siphash24_compress(p, sizeof(sd_id128_t), state);
+}
+
+int id128_compare_func(const sd_id128_t *a, const sd_id128_t *b) {
+        return memcmp(a, b, 16);
+}
+
+sd_id128_t id128_make_v4_uuid(sd_id128_t id) {
+        /* Stolen from generate_random_uuid() of drivers/char/random.c
+         * in the kernel sources */
+
+        /* Set UUID version to 4 --- truly random generation */
+        id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
+
+        /* Set the UUID variant to DCE */
+        id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
+
+        return id;
+}
+
+DEFINE_HASH_OPS(id128_hash_ops, sd_id128_t, id128_hash_func, id128_compare_func);
diff --git a/src/libsystemd/sd-id128/id128-util.h b/src/libsystemd/sd-id128/id128-util.h
new file mode 100644
index 0000000..6b09bcd
--- /dev/null
+++ b/src/libsystemd/sd-id128/id128-util.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdbool.h>
+
+#include "sd-id128.h"
+
+#include "hash-funcs.h"
+#include "macro.h"
+
+#define ID128_UUID_STRING_MAX 37
+
+char *id128_to_uuid_string(sd_id128_t id, char s[static ID128_UUID_STRING_MAX]);
+
+bool id128_is_valid(const char *s) _pure_;
+
+typedef enum Id128Format {
+        ID128_ANY,
+        ID128_PLAIN,  /* formatted as 32 hex chars as-is */
+        ID128_PLAIN_OR_UNINIT,  /* formatted as 32 hex chars as-is; allow special "uninitialized"
+                                 * value when reading from file (id128_read() and id128_read_fd()).
+                                 *
+                                 * This format should be used when reading a machine-id file. */
+        ID128_UUID,   /* formatted as 36 character uuid string */
+        _ID128_FORMAT_MAX,
+} Id128Format;
+
+int id128_read_fd(int fd, Id128Format f, sd_id128_t *ret);
+int id128_read(const char *p, Id128Format f, sd_id128_t *ret);
+
+int id128_write_fd(int fd, Id128Format f, sd_id128_t id, bool do_sync);
+int id128_write(const char *p, Id128Format f, sd_id128_t id, bool do_sync);
+
+void id128_hash_func(const sd_id128_t *p, struct siphash *state);
+int id128_compare_func(const sd_id128_t *a, const sd_id128_t *b) _pure_;
+extern const struct hash_ops id128_hash_ops;
+
+sd_id128_t id128_make_v4_uuid(sd_id128_t id);
diff --git a/src/libsystemd/sd-id128/sd-id128.c b/src/libsystemd/sd-id128/sd-id128.c
new file mode 100644
index 0000000..d5de935
--- /dev/null
+++ b/src/libsystemd/sd-id128/sd-id128.c
@@ -0,0 +1,324 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "sd-id128.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "hexdecoct.h"
+#include "id128-util.h"
+#include "io-util.h"
+#include "khash.h"
+#include "macro.h"
+#include "missing_syscall.h"
+#include "random-util.h"
+#include "user-util.h"
+#include "util.h"
+
+_public_ char *sd_id128_to_string(sd_id128_t id, char s[_SD_ARRAY_STATIC SD_ID128_STRING_MAX]) {
+        unsigned n;
+
+        assert_return(s, NULL);
+
+        for (n = 0; n < 16; n++) {
+                s[n*2] = hexchar(id.bytes[n] >> 4);
+                s[n*2+1] = hexchar(id.bytes[n] & 0xF);
+        }
+
+        s[32] = 0;
+
+        return s;
+}
+
+_public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) {
+        unsigned n, i;
+        sd_id128_t t;
+        bool is_guid = false;
+
+        assert_return(s, -EINVAL);
+
+        for (n = 0, i = 0; n < 16;) {
+                int a, b;
+
+                if (s[i] == '-') {
+                        /* Is this a GUID? Then be nice, and skip over
+                         * the dashes */
+
+                        if (i == 8)
+                                is_guid = true;
+                        else if (IN_SET(i, 13, 18, 23)) {
+                                if (!is_guid)
+                                        return -EINVAL;
+                        } else
+                                return -EINVAL;
+
+                        i++;
+                        continue;
+                }
+
+                a = unhexchar(s[i++]);
+                if (a < 0)
+                        return -EINVAL;
+
+                b = unhexchar(s[i++]);
+                if (b < 0)
+                        return -EINVAL;
+
+                t.bytes[n++] = (a << 4) | b;
+        }
+
+        if (i != (is_guid ? 36 : 32))
+                return -EINVAL;
+
+        if (s[i] != 0)
+                return -EINVAL;
+
+        if (ret)
+                *ret = t;
+        return 0;
+}
+
+_public_ int sd_id128_get_machine(sd_id128_t *ret) {
+        static thread_local sd_id128_t saved_machine_id = {};
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        if (sd_id128_is_null(saved_machine_id)) {
+                r = id128_read("/etc/machine-id", ID128_PLAIN, &saved_machine_id);
+                if (r < 0)
+                        return r;
+
+                if (sd_id128_is_null(saved_machine_id))
+                        return -ENOMEDIUM;
+        }
+
+        *ret = saved_machine_id;
+        return 0;
+}
+
+_public_ int sd_id128_get_boot(sd_id128_t *ret) {
+        static thread_local sd_id128_t saved_boot_id = {};
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        if (sd_id128_is_null(saved_boot_id)) {
+                r = id128_read("/proc/sys/kernel/random/boot_id", ID128_UUID, &saved_boot_id);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = saved_boot_id;
+        return 0;
+}
+
+static int get_invocation_from_keyring(sd_id128_t *ret) {
+        _cleanup_free_ char *description = NULL;
+        char *d, *p, *g, *u, *e;
+        unsigned long perms;
+        key_serial_t key;
+        size_t sz = 256;
+        uid_t uid;
+        gid_t gid;
+        int r, c;
+
+#define MAX_PERMS ((unsigned long) (KEY_POS_VIEW|KEY_POS_READ|KEY_POS_SEARCH| \
+                                    KEY_USR_VIEW|KEY_USR_READ|KEY_USR_SEARCH))
+
+        assert(ret);
+
+        key = request_key("user", "invocation_id", NULL, 0);
+        if (key == -1) {
+                /* Keyring support not available? No invocation key stored? */
+                if (IN_SET(errno, ENOSYS, ENOKEY))
+                        return -ENXIO;
+
+                return -errno;
+        }
+
+        for (;;) {
+                description = new(char, sz);
+                if (!description)
+                        return -ENOMEM;
+
+                c = keyctl(KEYCTL_DESCRIBE, key, (unsigned long) description, sz, 0);
+                if (c < 0)
+                        return -errno;
+
+                if ((size_t) c <= sz)
+                        break;
+
+                sz = c;
+                free(description);
+        }
+
+        /* The kernel returns a final NUL in the string, verify that. */
+        assert(description[c-1] == 0);
+
+        /* Chop off the final description string */
+        d = strrchr(description, ';');
+        if (!d)
+                return -EIO;
+        *d = 0;
+
+        /* Look for the permissions */
+        p = strrchr(description, ';');
+        if (!p)
+                return -EIO;
+
+        errno = 0;
+        perms = strtoul(p + 1, &e, 16);
+        if (errno > 0)
+                return -errno;
+        if (e == p + 1) /* Read at least one character */
+                return -EIO;
+        if (e != d) /* Must reached the end */
+                return -EIO;
+
+        if ((perms & ~MAX_PERMS) != 0)
+                return -EPERM;
+
+        *p = 0;
+
+        /* Look for the group ID */
+        g = strrchr(description, ';');
+        if (!g)
+                return -EIO;
+        r = parse_gid(g + 1, &gid);
+        if (r < 0)
+                return r;
+        if (gid != 0)
+                return -EPERM;
+        *g = 0;
+
+        /* Look for the user ID */
+        u = strrchr(description, ';');
+        if (!u)
+                return -EIO;
+        r = parse_uid(u + 1, &uid);
+        if (r < 0)
+                return r;
+        if (uid != 0)
+                return -EPERM;
+
+        c = keyctl(KEYCTL_READ, key, (unsigned long) ret, sizeof(sd_id128_t), 0);
+        if (c < 0)
+                return -errno;
+        if (c != sizeof(sd_id128_t))
+                return -EIO;
+
+        return 0;
+}
+
+static int get_invocation_from_environment(sd_id128_t *ret) {
+        const char *e;
+
+        assert(ret);
+
+        e = secure_getenv("INVOCATION_ID");
+        if (!e)
+                return -ENXIO;
+
+        return sd_id128_from_string(e, ret);
+}
+
+_public_ int sd_id128_get_invocation(sd_id128_t *ret) {
+        static thread_local sd_id128_t saved_invocation_id = {};
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        if (sd_id128_is_null(saved_invocation_id)) {
+                /* We first check the environment. The environment variable is primarily relevant for user
+                 * services, and sufficiently safe as long as no privilege boundary is involved. */
+                r = get_invocation_from_environment(&saved_invocation_id);
+                if (r < 0 && r != -ENXIO)
+                        return r;
+
+                /* The kernel keyring is relevant for system services (as for user services we don't store
+                 * the invocation ID in the keyring, as there'd be no trust benefit in that). */
+                r = get_invocation_from_keyring(&saved_invocation_id);
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = saved_invocation_id;
+        return 0;
+}
+
+_public_ int sd_id128_randomize(sd_id128_t *ret) {
+        sd_id128_t t;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        /* We allow usage if x86-64 RDRAND here. It might not be trusted enough for keeping secrets, but it should be
+         * fine for UUIDS. */
+        r = genuine_random_bytes(&t, sizeof t, RANDOM_ALLOW_RDRAND);
+        if (r < 0)
+                return r;
+
+        /* Turn this into a valid v4 UUID, to be nice. Note that we
+         * only guarantee this for newly generated UUIDs, not for
+         * pre-existing ones. */
+
+        *ret = id128_make_v4_uuid(t);
+        return 0;
+}
+
+static int get_app_specific(sd_id128_t base, sd_id128_t app_id, sd_id128_t *ret) {
+        _cleanup_(khash_unrefp) khash *h = NULL;
+        sd_id128_t result;
+        const void *p;
+        int r;
+
+        assert(ret);
+
+        r = khash_new_with_key(&h, "hmac(sha256)", &base, sizeof(base));
+        if (r < 0)
+                return r;
+
+        r = khash_put(h, &app_id, sizeof(app_id));
+        if (r < 0)
+                return r;
+
+        r = khash_digest_data(h, &p);
+        if (r < 0)
+                return r;
+
+        /* We chop off the trailing 16 bytes */
+        memcpy(&result, p, MIN(khash_get_size(h), sizeof(result)));
+
+        *ret = id128_make_v4_uuid(result);
+        return 0;
+}
+
+_public_ int sd_id128_get_machine_app_specific(sd_id128_t app_id, sd_id128_t *ret) {
+        sd_id128_t id;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_id128_get_machine(&id);
+        if (r < 0)
+                return r;
+
+        return get_app_specific(id, app_id, ret);
+}
+
+_public_ int sd_id128_get_boot_app_specific(sd_id128_t app_id, sd_id128_t *ret) {
+        sd_id128_t id;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_id128_get_boot(&id);
+        if (r < 0)
+                return r;
+
+        return get_app_specific(id, app_id, ret);
+}
diff --git a/src/libsystemd/sd-login/sd-login.c b/src/libsystemd/sd-login/sd-login.c
new file mode 100644
index 0000000..1fc3795
--- /dev/null
+++ b/src/libsystemd/sd-login/sd-login.c
@@ -0,0 +1,1051 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <poll.h>
+#include <sys/inotify.h>
+#include <unistd.h>
+
+#include "sd-login.h"
+
+#include "alloc-util.h"
+#include "cgroup-util.h"
+#include "dirent-util.h"
+#include "env-file.h"
+#include "escape.h"
+#include "extract-word.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "hostname-util.h"
+#include "io-util.h"
+#include "login-util.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "socket-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+#include "util.h"
+
+/* Error codes:
+ *
+ *    invalid input parameters                → -EINVAL
+ *    invalid fd                              → -EBADF
+ *    process does not exist                  → -ESRCH
+ *    cgroup does not exist                   → -ENOENT
+ *    machine, session does not exist         → -ENXIO
+ *    requested metadata on object is missing → -ENODATA
+ */
+
+_public_ int sd_pid_get_session(pid_t pid, char **session) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(session, -EINVAL);
+
+        r = cg_pid_get_session(pid, session);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_unit(pid_t pid, char **unit) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(unit, -EINVAL);
+
+        r = cg_pid_get_unit(pid, unit);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_user_unit(pid_t pid, char **unit) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(unit, -EINVAL);
+
+        r = cg_pid_get_user_unit(pid, unit);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_machine_name(pid_t pid, char **name) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(name, -EINVAL);
+
+        r = cg_pid_get_machine_name(pid, name);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_slice(pid_t pid, char **slice) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(slice, -EINVAL);
+
+        r = cg_pid_get_slice(pid, slice);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_user_slice(pid_t pid, char **slice) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(slice, -EINVAL);
+
+        r = cg_pid_get_user_slice(pid, slice);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_owner_uid(pid_t pid, uid_t *uid) {
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(uid, -EINVAL);
+
+        r = cg_pid_get_owner_uid(pid, uid);
+        return IN_SET(r, -ENXIO, -ENOMEDIUM) ? -ENODATA : r;
+}
+
+_public_ int sd_pid_get_cgroup(pid_t pid, char **cgroup) {
+        char *c;
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(cgroup, -EINVAL);
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &c);
+        if (r < 0)
+                return r;
+
+        /* The internal APIs return the empty string for the root
+         * cgroup, let's return the "/" in the public APIs instead, as
+         * that's easier and less ambiguous for people to grok. */
+        if (isempty(c)) {
+                free(c);
+                c = strdup("/");
+                if (!c)
+                        return -ENOMEM;
+
+        }
+
+        *cgroup = c;
+        return 0;
+}
+
+_public_ int sd_peer_get_session(int fd, char **session) {
+        struct ucred ucred = {};
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(session, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_session(ucred.pid, session);
+}
+
+_public_ int sd_peer_get_owner_uid(int fd, uid_t *uid) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(uid, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_owner_uid(ucred.pid, uid);
+}
+
+_public_ int sd_peer_get_unit(int fd, char **unit) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(unit, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_unit(ucred.pid, unit);
+}
+
+_public_ int sd_peer_get_user_unit(int fd, char **unit) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(unit, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_user_unit(ucred.pid, unit);
+}
+
+_public_ int sd_peer_get_machine_name(int fd, char **machine) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(machine, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_machine_name(ucred.pid, machine);
+}
+
+_public_ int sd_peer_get_slice(int fd, char **slice) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(slice, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_slice(ucred.pid, slice);
+}
+
+_public_ int sd_peer_get_user_slice(int fd, char **slice) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(slice, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return cg_pid_get_user_slice(ucred.pid, slice);
+}
+
+_public_ int sd_peer_get_cgroup(int fd, char **cgroup) {
+        struct ucred ucred;
+        int r;
+
+        assert_return(fd >= 0, -EBADF);
+        assert_return(cgroup, -EINVAL);
+
+        r = getpeercred(fd, &ucred);
+        if (r < 0)
+                return r;
+
+        return sd_pid_get_cgroup(ucred.pid, cgroup);
+}
+
+static int file_of_uid(uid_t uid, char **p) {
+
+        assert_return(uid_is_valid(uid), -EINVAL);
+        assert(p);
+
+        if (asprintf(p, "/run/systemd/users/" UID_FMT, uid) < 0)
+                return -ENOMEM;
+
+        return 0;
+}
+
+_public_ int sd_uid_get_state(uid_t uid, char**state) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        assert_return(state, -EINVAL);
+
+        r = file_of_uid(uid, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, "STATE", &s);
+        if (r == -ENOENT) {
+                r = free_and_strdup(&s, "offline");
+                if (r < 0)
+                        return r;
+        } else if (r < 0)
+                return r;
+        else if (isempty(s))
+                return -EIO;
+
+        *state = TAKE_PTR(s);
+        return 0;
+}
+
+_public_ int sd_uid_get_display(uid_t uid, char **session) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        assert_return(session, -EINVAL);
+
+        r = file_of_uid(uid, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, "DISPLAY", &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+
+        *session = TAKE_PTR(s);
+
+        return 0;
+}
+
+static int file_of_seat(const char *seat, char **_p) {
+        char *p;
+        int r;
+
+        assert(_p);
+
+        if (seat) {
+                if (!filename_is_valid(seat))
+                        return -EINVAL;
+
+                p = path_join("/run/systemd/seats", seat);
+        } else {
+                _cleanup_free_ char *buf = NULL;
+
+                r = sd_session_get_seat(NULL, &buf);
+                if (r < 0)
+                        return r;
+
+                p = path_join("/run/systemd/seats", buf);
+        }
+        if (!p)
+                return -ENOMEM;
+
+        *_p = TAKE_PTR(p);
+        return 0;
+}
+
+_public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat) {
+        _cleanup_free_ char *filename = NULL, *content = NULL;
+        int r;
+
+        assert_return(uid_is_valid(uid), -EINVAL);
+
+        r = file_of_seat(seat, &filename);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, filename,
+                           require_active ? "ACTIVE_UID" : "UIDS",
+                           &content);
+        if (r == -ENOENT)
+                return 0;
+        if (r < 0)
+                return r;
+        if (isempty(content))
+                return 0;
+
+        char t[DECIMAL_STR_MAX(uid_t)];
+        xsprintf(t, UID_FMT, uid);
+
+        return string_contains_word(content, NULL, t);
+}
+
+static int uid_get_array(uid_t uid, const char *variable, char ***array) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        char **a;
+        int r;
+
+        assert(variable);
+
+        r = file_of_uid(uid, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, variable, &s);
+        if (r == -ENOENT || (r >= 0 && isempty(s))) {
+                if (array)
+                        *array = NULL;
+                return 0;
+        }
+        if (r < 0)
+                return r;
+
+        a = strv_split(s, NULL);
+        if (!a)
+                return -ENOMEM;
+
+        strv_uniq(a);
+        r = (int) strv_length(a);
+
+        if (array)
+                *array = a;
+        else
+                strv_free(a);
+
+        return r;
+}
+
+_public_ int sd_uid_get_sessions(uid_t uid, int require_active, char ***sessions) {
+        return uid_get_array(
+                        uid,
+                        require_active == 0 ? "ONLINE_SESSIONS" :
+                        require_active > 0  ? "ACTIVE_SESSIONS" :
+                                              "SESSIONS",
+                        sessions);
+}
+
+_public_ int sd_uid_get_seats(uid_t uid, int require_active, char ***seats) {
+        return uid_get_array(
+                        uid,
+                        require_active == 0 ? "ONLINE_SEATS" :
+                        require_active > 0  ? "ACTIVE_SEATS" :
+                                              "SEATS",
+                        seats);
+}
+
+static int file_of_session(const char *session, char **_p) {
+        char *p;
+        int r;
+
+        assert(_p);
+
+        if (session) {
+                if (!session_id_valid(session))
+                        return -EINVAL;
+
+                p = path_join("/run/systemd/sessions", session);
+        } else {
+                _cleanup_free_ char *buf = NULL;
+
+                r = sd_pid_get_session(0, &buf);
+                if (r < 0)
+                        return r;
+
+                p = path_join("/run/systemd/sessions", buf);
+        }
+
+        if (!p)
+                return -ENOMEM;
+
+        *_p = p;
+        return 0;
+}
+
+_public_ int sd_session_is_active(const char *session) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        r = file_of_session(session, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, "ACTIVE", &s);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -EIO;
+
+        return parse_boolean(s);
+}
+
+_public_ int sd_session_is_remote(const char *session) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        r = file_of_session(session, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, "REMOTE", &s);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+
+        return parse_boolean(s);
+}
+
+_public_ int sd_session_get_state(const char *session, char **state) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        assert_return(state, -EINVAL);
+
+        r = file_of_session(session, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, "STATE", &s);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -EIO;
+
+        *state = TAKE_PTR(s);
+
+        return 0;
+}
+
+_public_ int sd_session_get_uid(const char *session, uid_t *uid) {
+        int r;
+        _cleanup_free_ char *p = NULL, *s = NULL;
+
+        assert_return(uid, -EINVAL);
+
+        r = file_of_session(session, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, "UID", &s);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -EIO;
+
+        return parse_uid(s, uid);
+}
+
+static int session_get_string(const char *session, const char *field, char **value) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        assert_return(value, -EINVAL);
+        assert(field);
+
+        r = file_of_session(session, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p, field, &s);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+
+        *value = TAKE_PTR(s);
+        return 0;
+}
+
+_public_ int sd_session_get_seat(const char *session, char **seat) {
+        return session_get_string(session, "SEAT", seat);
+}
+
+_public_ int sd_session_get_tty(const char *session, char **tty) {
+        return session_get_string(session, "TTY", tty);
+}
+
+_public_ int sd_session_get_vt(const char *session, unsigned *vtnr) {
+        _cleanup_free_ char *vtnr_string = NULL;
+        unsigned u;
+        int r;
+
+        assert_return(vtnr, -EINVAL);
+
+        r = session_get_string(session, "VTNR", &vtnr_string);
+        if (r < 0)
+                return r;
+
+        r = safe_atou(vtnr_string, &u);
+        if (r < 0)
+                return r;
+
+        *vtnr = u;
+        return 0;
+}
+
+_public_ int sd_session_get_service(const char *session, char **service) {
+        return session_get_string(session, "SERVICE", service);
+}
+
+_public_ int sd_session_get_type(const char *session, char **type) {
+        return session_get_string(session, "TYPE", type);
+}
+
+_public_ int sd_session_get_class(const char *session, char **class) {
+        return session_get_string(session, "CLASS", class);
+}
+
+_public_ int sd_session_get_desktop(const char *session, char **desktop) {
+        _cleanup_free_ char *escaped = NULL;
+        char *t;
+        int r;
+
+        assert_return(desktop, -EINVAL);
+
+        r = session_get_string(session, "DESKTOP", &escaped);
+        if (r < 0)
+                return r;
+
+        r = cunescape(escaped, 0, &t);
+        if (r < 0)
+                return r;
+
+        *desktop = t;
+        return 0;
+}
+
+_public_ int sd_session_get_display(const char *session, char **display) {
+        return session_get_string(session, "DISPLAY", display);
+}
+
+_public_ int sd_session_get_remote_user(const char *session, char **remote_user) {
+        return session_get_string(session, "REMOTE_USER", remote_user);
+}
+
+_public_ int sd_session_get_remote_host(const char *session, char **remote_host) {
+        return session_get_string(session, "REMOTE_HOST", remote_host);
+}
+
+_public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) {
+        _cleanup_free_ char *p = NULL, *s = NULL, *t = NULL;
+        int r;
+
+        assert_return(session || uid, -EINVAL);
+
+        r = file_of_seat(seat, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p,
+                           "ACTIVE", &s,
+                           "ACTIVE_UID", &t);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+
+        if (session && !s)
+                return -ENODATA;
+
+        if (uid && !t)
+                return -ENODATA;
+
+        if (uid && t) {
+                r = parse_uid(t, uid);
+                if (r < 0)
+                        return r;
+        }
+
+        if (session && s)
+                *session = TAKE_PTR(s);
+
+        return 0;
+}
+
+_public_ int sd_seat_get_sessions(
+                const char *seat,
+                char ***ret_sessions,
+                uid_t **ret_uids,
+                unsigned *ret_n_uids) {
+
+        _cleanup_free_ char *fname = NULL, *session_line = NULL, *uid_line = NULL;
+        _cleanup_strv_free_ char **sessions = NULL;
+        _cleanup_free_ uid_t *uids = NULL;
+        unsigned n_sessions = 0;
+        int r;
+
+        r = file_of_seat(seat, &fname);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, fname,
+                           "SESSIONS", &session_line,
+                           "UIDS", &uid_line);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+
+        if (session_line) {
+                sessions = strv_split(session_line, NULL);
+                if (!sessions)
+                        return -ENOMEM;
+
+                n_sessions = strv_length(sessions);
+        };
+
+        if (ret_uids && uid_line) {
+                uids = new(uid_t, n_sessions);
+                if (!uids)
+                        return -ENOMEM;
+
+                size_t n = 0;
+                for (const char *p = uid_line;;) {
+                        _cleanup_free_ char *word = NULL;
+
+                        r = extract_first_word(&p, &word, NULL, 0);
+                        if (r < 0)
+                                return r;
+                        if (r == 0)
+                                break;
+
+                        r = parse_uid(word, &uids[n++]);
+                        if (r < 0)
+                                return r;
+                }
+
+                if (n != n_sessions)
+                        return -EUCLEAN;
+        }
+
+        if (ret_sessions)
+                *ret_sessions = TAKE_PTR(sessions);
+        if (ret_uids)
+                *ret_uids = TAKE_PTR(uids);
+        if (ret_n_uids)
+                *ret_n_uids = n_sessions;
+
+        return n_sessions;
+}
+
+static int seat_get_can(const char *seat, const char *variable) {
+        _cleanup_free_ char *p = NULL, *s = NULL;
+        int r;
+
+        assert(variable);
+
+        r = file_of_seat(seat, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(NULL, p,
+                           variable, &s);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+
+        return parse_boolean(s);
+}
+
+_public_ int sd_seat_can_multi_session(const char *seat) {
+        return true;
+}
+
+_public_ int sd_seat_can_tty(const char *seat) {
+        return seat_get_can(seat, "CAN_TTY");
+}
+
+_public_ int sd_seat_can_graphical(const char *seat) {
+        return seat_get_can(seat, "CAN_GRAPHICAL");
+}
+
+_public_ int sd_get_seats(char ***seats) {
+        int r;
+
+        r = get_files_in_directory("/run/systemd/seats/", seats);
+        if (r == -ENOENT) {
+                if (seats)
+                        *seats = NULL;
+                return 0;
+        }
+        return r;
+}
+
+_public_ int sd_get_sessions(char ***sessions) {
+        int r;
+
+        r = get_files_in_directory("/run/systemd/sessions/", sessions);
+        if (r == -ENOENT) {
+                if (sessions)
+                        *sessions = NULL;
+                return 0;
+        }
+        return r;
+}
+
+_public_ int sd_get_uids(uid_t **users) {
+        _cleanup_closedir_ DIR *d;
+        struct dirent *de;
+        int r = 0;
+        unsigned n = 0;
+        _cleanup_free_ uid_t *l = NULL;
+
+        d = opendir("/run/systemd/users/");
+        if (!d) {
+                if (errno == ENOENT) {
+                        if (users)
+                                *users = NULL;
+                        return 0;
+                }
+                return -errno;
+        }
+
+        FOREACH_DIRENT_ALL(de, d, return -errno) {
+                int k;
+                uid_t uid;
+
+                dirent_ensure_type(d, de);
+
+                if (!dirent_is_file(de))
+                        continue;
+
+                k = parse_uid(de->d_name, &uid);
+                if (k < 0)
+                        continue;
+
+                if (users) {
+                        if ((unsigned) r >= n) {
+                                uid_t *t;
+
+                                n = MAX(16, 2*r);
+                                t = reallocarray(l, sizeof(uid_t), n);
+                                if (!t)
+                                        return -ENOMEM;
+
+                                l = t;
+                        }
+
+                        assert((unsigned) r < n);
+                        l[r++] = uid;
+                } else
+                        r++;
+        }
+
+        if (users)
+                *users = TAKE_PTR(l);
+
+        return r;
+}
+
+_public_ int sd_get_machine_names(char ***machines) {
+        _cleanup_strv_free_ char **l = NULL;
+        char **a, **b;
+        int r;
+
+        r = get_files_in_directory("/run/systemd/machines/", &l);
+        if (r == -ENOENT) {
+                if (machines)
+                        *machines = NULL;
+                return 0;
+        }
+        if (r < 0)
+                return r;
+
+        if (l) {
+                r = 0;
+
+                /* Filter out the unit: symlinks */
+                for (a = b = l; *a; a++) {
+                        if (startswith(*a, "unit:") || !machine_name_is_valid(*a))
+                                free(*a);
+                        else {
+                                *b = *a;
+                                b++;
+                                r++;
+                        }
+                }
+
+                *b = NULL;
+        }
+
+        if (machines)
+                *machines = TAKE_PTR(l);
+
+        return r;
+}
+
+_public_ int sd_machine_get_class(const char *machine, char **class) {
+        _cleanup_free_ char *c = NULL;
+        const char *p;
+        int r;
+
+        assert_return(class, -EINVAL);
+
+        if (streq(machine, ".host")) {
+                c = strdup("host");
+                if (!c)
+                        return -ENOMEM;
+        } else {
+                if (!machine_name_is_valid(machine))
+                        return -EINVAL;
+
+                p = strjoina("/run/systemd/machines/", machine);
+                r = parse_env_file(NULL, p, "CLASS", &c);
+                if (r == -ENOENT)
+                        return -ENXIO;
+                if (r < 0)
+                        return r;
+                if (!c)
+                        return -EIO;
+        }
+
+        *class = TAKE_PTR(c);
+        return 0;
+}
+
+_public_ int sd_machine_get_ifindices(const char *machine, int **ret_ifindices) {
+        _cleanup_free_ char *netif_line = NULL;
+        const char *p;
+        int r;
+
+        assert_return(machine_name_is_valid(machine), -EINVAL);
+
+        p = strjoina("/run/systemd/machines/", machine);
+        r = parse_env_file(NULL, p, "NETIF", &netif_line);
+        if (r == -ENOENT)
+                return -ENXIO;
+        if (r < 0)
+                return r;
+        if (!netif_line) {
+                *ret_ifindices = NULL;
+                return 0;
+        }
+
+        _cleanup_strv_free_ char **tt = strv_split(netif_line, NULL);
+        if (!tt)
+                return -ENOMEM;
+
+        _cleanup_free_ int *ifindices = NULL;
+        if (ret_ifindices) {
+                ifindices = new(int, strv_length(tt));
+                if (!ifindices)
+                        return -ENOMEM;
+        }
+
+        size_t n = 0;
+        for (size_t i = 0; tt[i]; i++) {
+                int ind;
+
+                ind = parse_ifindex(tt[i]);
+                if (ind < 0)
+                        /* Return -EUCLEAN to distinguish from -EINVAL for invalid args */
+                        return ind == -EINVAL ? -EUCLEAN : ind;
+
+                if (ret_ifindices)
+                        ifindices[n] = ind;
+                n++;
+        }
+
+        if (ret_ifindices)
+                *ret_ifindices = TAKE_PTR(ifindices);
+
+        return n;
+}
+
+static int MONITOR_TO_FD(sd_login_monitor *m) {
+        return (int) (unsigned long) m - 1;
+}
+
+static sd_login_monitor* FD_TO_MONITOR(int fd) {
+        return (sd_login_monitor*) (unsigned long) (fd + 1);
+}
+
+_public_ int sd_login_monitor_new(const char *category, sd_login_monitor **m) {
+        _cleanup_close_ int fd = -1;
+        bool good = false;
+        int k;
+
+        assert_return(m, -EINVAL);
+
+        fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        if (!category || streq(category, "seat")) {
+                k = inotify_add_watch(fd, "/run/systemd/seats/", IN_MOVED_TO|IN_DELETE);
+                if (k < 0)
+                        return -errno;
+
+                good = true;
+        }
+
+        if (!category || streq(category, "session")) {
+                k = inotify_add_watch(fd, "/run/systemd/sessions/", IN_MOVED_TO|IN_DELETE);
+                if (k < 0)
+                        return -errno;
+
+                good = true;
+        }
+
+        if (!category || streq(category, "uid")) {
+                k = inotify_add_watch(fd, "/run/systemd/users/", IN_MOVED_TO|IN_DELETE);
+                if (k < 0)
+                        return -errno;
+
+                good = true;
+        }
+
+        if (!category || streq(category, "machine")) {
+                k = inotify_add_watch(fd, "/run/systemd/machines/", IN_MOVED_TO|IN_DELETE);
+                if (k < 0)
+                        return -errno;
+
+                good = true;
+        }
+
+        if (!good)
+                return -EINVAL;
+
+        *m = FD_TO_MONITOR(TAKE_FD(fd));
+        return 0;
+}
+
+_public_ sd_login_monitor* sd_login_monitor_unref(sd_login_monitor *m) {
+        if (m)
+                close_nointr(MONITOR_TO_FD(m));
+
+        return NULL;
+}
+
+_public_ int sd_login_monitor_flush(sd_login_monitor *m) {
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = flush_fd(MONITOR_TO_FD(m));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+_public_ int sd_login_monitor_get_fd(sd_login_monitor *m) {
+
+        assert_return(m, -EINVAL);
+
+        return MONITOR_TO_FD(m);
+}
+
+_public_ int sd_login_monitor_get_events(sd_login_monitor *m) {
+
+        assert_return(m, -EINVAL);
+
+        /* For now we will only return POLLIN here, since we don't
+         * need anything else ever for inotify.  However, let's have
+         * this API to keep our options open should we later on need
+         * it. */
+        return POLLIN;
+}
+
+_public_ int sd_login_monitor_get_timeout(sd_login_monitor *m, uint64_t *timeout_usec) {
+
+        assert_return(m, -EINVAL);
+        assert_return(timeout_usec, -EINVAL);
+
+        /* For now we will only return (uint64_t) -1, since we don't
+         * need any timeout. However, let's have this API to keep our
+         * options open should we later on need it. */
+        *timeout_usec = (uint64_t) -1;
+        return 0;
+}
diff --git a/src/libsystemd/sd-login/test-login.c b/src/libsystemd/sd-login/test-login.c
new file mode 100644
index 0000000..d850323
--- /dev/null
+++ b/src/libsystemd/sd-login/test-login.c
@@ -0,0 +1,305 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <poll.h>
+
+#include "sd-login.h"
+
+#include "alloc-util.h"
+#include "errno-list.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "log.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "user-util.h"
+
+static char* format_uids(char **buf, uid_t* uids, int count) {
+        int pos = 0, inc;
+        size_t size = (DECIMAL_STR_MAX(uid_t) + 1) * count + 1;
+
+        assert_se(*buf = malloc(size));
+
+        for (int k = 0; k < count; k++) {
+                sprintf(*buf + pos, "%s"UID_FMT"%n", k > 0 ? " " : "", uids[k], &inc);
+                pos += inc;
+        }
+
+        assert_se(pos < (ssize_t)size);
+        (*buf)[pos] = '\0';
+
+        return *buf;
+}
+
+static const char *e(int r) {
+        return r == 0 ? "OK" : errno_to_name(r);
+}
+
+static void test_login(void) {
+        _cleanup_close_pair_ int pair[2] = { -1, -1 };
+        _cleanup_free_ char *pp = NULL, *qq = NULL,
+                *display_session = NULL, *cgroup = NULL,
+                *display = NULL, *remote_user = NULL, *remote_host = NULL,
+                *type = NULL, *class = NULL, *state = NULL, *state2 = NULL,
+                *seat = NULL, *session = NULL,
+                *unit = NULL, *user_unit = NULL, *slice = NULL;
+        int r;
+        uid_t u, u2 = UID_INVALID;
+        char *t, **seats = NULL, **sessions = NULL;
+
+        r = sd_pid_get_unit(0, &unit);
+        log_info("sd_pid_get_unit(0, …) → %s / \"%s\"", e(r), strnull(unit));
+        assert_se(IN_SET(r, 0, -ENODATA));
+
+        r = sd_pid_get_user_unit(0, &user_unit);
+        log_info("sd_pid_get_user_unit(0, …) → %s / \"%s\"", e(r), strnull(user_unit));
+        assert_se(IN_SET(r, 0, -ENODATA));
+
+        r = sd_pid_get_slice(0, &slice);
+        log_info("sd_pid_get_slice(0, …) → %s / \"%s\"", e(r), strnull(slice));
+        assert_se(IN_SET(r, 0, -ENODATA));
+
+        r = sd_pid_get_owner_uid(0, &u2);
+        log_info("sd_pid_get_owner_uid(0, …) → %s / "UID_FMT, e(r), u2);
+        assert_se(IN_SET(r, 0, -ENODATA));
+
+        r = sd_pid_get_session(0, &session);
+        log_info("sd_pid_get_session(0, …) → %s / \"%s\"", e(r), strnull(session));
+
+        r = sd_pid_get_cgroup(0, &cgroup);
+        log_info("sd_pid_get_cgroup(0, …) → %s / \"%s\"", e(r), strnull(cgroup));
+        assert_se(IN_SET(r, 0, -ENOMEDIUM));
+
+        r = sd_uid_get_display(u2, &display_session);
+        log_info("sd_uid_get_display("UID_FMT", …) → %s / \"%s\"", u2, e(r), strnull(display_session));
+        if (u2 == UID_INVALID)
+                assert_se(r == -EINVAL);
+        else
+                assert_se(IN_SET(r, 0, -ENODATA));
+
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == 0);
+        sd_peer_get_session(pair[0], &pp);
+        sd_peer_get_session(pair[1], &qq);
+        assert_se(streq_ptr(pp, qq));
+
+        r = sd_uid_get_sessions(u2, false, &sessions);
+        assert_se(t = strv_join(sessions, " "));
+        log_info("sd_uid_get_sessions("UID_FMT", …) → %s \"%s\"", u2, e(r), t);
+        if (u2 == UID_INVALID)
+                assert_se(r == -EINVAL);
+        else {
+                assert_se(r >= 0);
+                assert_se(r == (int) strv_length(sessions));
+        }
+        sessions = strv_free(sessions);
+        free(t);
+
+        assert_se(r == sd_uid_get_sessions(u2, false, NULL));
+
+        r = sd_uid_get_seats(u2, false, &seats);
+        assert_se(t = strv_join(seats, " "));
+        log_info("sd_uid_get_seats("UID_FMT", …) → %s \"%s\"", u2, e(r), t);
+        if (u2 == UID_INVALID)
+                assert_se(r == -EINVAL);
+        else {
+                assert_se(r >= 0);
+                assert_se(r == (int) strv_length(seats));
+        }
+        seats = strv_free(seats);
+        free(t);
+
+        assert_se(r == sd_uid_get_seats(u2, false, NULL));
+
+        if (session) {
+                r = sd_session_is_active(session);
+                if (r == -ENXIO)
+                        log_notice("sd_session_is_active() failed with ENXIO, it seems logind is not running.");
+                else {
+                        /* All those tests will fail with ENXIO, so let's skip them. */
+
+                        assert_se(r >= 0);
+                        log_info("sd_session_is_active(\"%s\") → %s", session, yes_no(r));
+
+                        r = sd_session_is_remote(session);
+                        assert_se(r >= 0);
+                        log_info("sd_session_is_remote(\"%s\") → %s", session, yes_no(r));
+
+                        r = sd_session_get_state(session, &state);
+                        assert_se(r == 0);
+                        log_info("sd_session_get_state(\"%s\") → \"%s\"", session, state);
+
+                        assert_se(sd_session_get_uid(session, &u) >= 0);
+                        log_info("sd_session_get_uid(\"%s\") → "UID_FMT, session, u);
+                        assert_se(u == u2);
+
+                        assert_se(sd_session_get_type(session, &type) >= 0);
+                        log_info("sd_session_get_type(\"%s\") → \"%s\"", session, type);
+
+                        assert_se(sd_session_get_class(session, &class) >= 0);
+                        log_info("sd_session_get_class(\"%s\") → \"%s\"", session, class);
+
+                        r = sd_session_get_display(session, &display);
+                        assert_se(IN_SET(r, 0, -ENODATA));
+                        log_info("sd_session_get_display(\"%s\") → \"%s\"", session, strna(display));
+
+                        r = sd_session_get_remote_user(session, &remote_user);
+                        assert_se(IN_SET(r, 0, -ENODATA));
+                        log_info("sd_session_get_remote_user(\"%s\") → \"%s\"",
+                                 session, strna(remote_user));
+
+                        r = sd_session_get_remote_host(session, &remote_host);
+                        assert_se(IN_SET(r, 0, -ENODATA));
+                        log_info("sd_session_get_remote_host(\"%s\") → \"%s\"",
+                                 session, strna(remote_host));
+
+                        r = sd_session_get_seat(session, &seat);
+                        if (r >= 0) {
+                                assert_se(seat);
+
+                                log_info("sd_session_get_seat(\"%s\") → \"%s\"", session, seat);
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+                                r = sd_seat_can_multi_session(seat);
+#pragma GCC diagnostic pop
+                                assert_se(r == 1);
+                                log_info("sd_session_can_multi_seat(\"%s\") → %s", seat, yes_no(r));
+
+                                r = sd_seat_can_tty(seat);
+                                assert_se(r >= 0);
+                                log_info("sd_session_can_tty(\"%s\") → %s", seat, yes_no(r));
+
+                                r = sd_seat_can_graphical(seat);
+                                assert_se(r >= 0);
+                                log_info("sd_session_can_graphical(\"%s\") → %s", seat, yes_no(r));
+                        } else {
+                                log_info_errno(r, "sd_session_get_seat(\"%s\"): %m", session);
+                                assert_se(r == -ENODATA);
+                        }
+
+                        assert_se(sd_uid_get_state(u, &state2) == 0);
+                        log_info("sd_uid_get_state("UID_FMT", …) → %s", u, state2);
+                }
+        }
+
+        if (seat) {
+                _cleanup_free_ char *session2 = NULL, *buf = NULL;
+                _cleanup_free_ uid_t *uids = NULL;
+                unsigned n;
+
+                assert_se(sd_uid_is_on_seat(u, 0, seat) > 0);
+
+                r = sd_seat_get_active(seat, &session2, &u2);
+                assert_se(r == 0);
+                log_info("sd_seat_get_active(\"%s\", …) → \"%s\", "UID_FMT, seat, session2, u2);
+
+                r = sd_uid_is_on_seat(u, 1, seat);
+                assert_se(IN_SET(r, 0, 1));
+                assert_se(!!r == streq(session, session2));
+
+                r = sd_seat_get_sessions(seat, &sessions, &uids, &n);
+                assert_se(r >= 0);
+                assert_se(r == (int) strv_length(sessions));
+                assert_se(t = strv_join(sessions, " "));
+                strv_free(sessions);
+                log_info("sd_seat_get_sessions(\"%s\", …) → %s, \"%s\", [%u] {%s}",
+                         seat, e(r), t, n, format_uids(&buf, uids, n));
+                free(t);
+
+                assert_se(sd_seat_get_sessions(seat, NULL, NULL, NULL) == r);
+        }
+
+        r = sd_get_seats(&seats);
+        assert_se(r >= 0);
+        assert_se(r == (int) strv_length(seats));
+        assert_se(t = strv_join(seats, ", "));
+        strv_free(seats);
+        log_info("sd_get_seats(…) → [%i] \"%s\"", r, t);
+        t = mfree(t);
+
+        assert_se(sd_get_seats(NULL) == r);
+
+        r = sd_seat_get_active(NULL, &t, NULL);
+        assert_se(IN_SET(r, 0, -ENODATA, -ENXIO));
+        log_info("sd_seat_get_active(NULL, …) (active session on current seat) → %s / \"%s\"", e(r), strnull(t));
+        free(t);
+
+        r = sd_get_sessions(&sessions);
+        assert_se(r >= 0);
+        assert_se(r == (int) strv_length(sessions));
+        assert_se(t = strv_join(sessions, ", "));
+        strv_free(sessions);
+        log_info("sd_get_sessions(…) → [%i] \"%s\"", r, t);
+        free(t);
+
+        assert_se(sd_get_sessions(NULL) == r);
+
+        {
+                _cleanup_free_ uid_t *uids = NULL;
+                _cleanup_free_ char *buf = NULL;
+
+                r = sd_get_uids(&uids);
+                assert_se(r >= 0);
+                log_info("sd_get_uids(…) → [%i] {%s}", r, format_uids(&buf, uids, r));
+
+                assert_se(sd_get_uids(NULL) == r);
+        }
+
+        {
+                _cleanup_strv_free_ char **machines = NULL;
+                _cleanup_free_ char *buf = NULL;
+
+                r = sd_get_machine_names(&machines);
+                assert_se(r >= 0);
+                assert_se(r == (int) strv_length(machines));
+                assert_se(buf = strv_join(machines, " "));
+                log_info("sd_get_machines(…) → [%i] \"%s\"", r, buf);
+
+                assert_se(sd_get_machine_names(NULL) == r);
+        }
+}
+
+static void test_monitor(void) {
+        sd_login_monitor *m = NULL;
+        int r;
+
+        assert_se(sd_login_monitor_new("session", &m) == 0);
+
+        for (unsigned n = 0; n < 5; n++) {
+                struct pollfd pollfd = {};
+                usec_t timeout, nw;
+
+                assert_se((pollfd.fd = sd_login_monitor_get_fd(m)) >= 0);
+                assert_se((pollfd.events = sd_login_monitor_get_events(m)) >= 0);
+
+                assert_se(sd_login_monitor_get_timeout(m, &timeout) >= 0);
+
+                nw = now(CLOCK_MONOTONIC);
+
+                r = poll(&pollfd, 1,
+                         timeout == (uint64_t) -1 ? -1 :
+                         timeout > nw ? (int) ((timeout - nw) / 1000) :
+                         0);
+
+                assert_se(r >= 0);
+
+                sd_login_monitor_flush(m);
+                printf("Wake!\n");
+        }
+
+        sd_login_monitor_unref(m);
+}
+
+int main(int argc, char* argv[]) {
+        log_parse_environment();
+        log_open();
+
+        log_info("/* Information printed is from the live system */");
+
+        test_login();
+
+        if (streq_ptr(argv[1], "-m"))
+                test_monitor();
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-netlink/generic-netlink.c b/src/libsystemd/sd-netlink/generic-netlink.c
new file mode 100644
index 0000000..f295fa9
--- /dev/null
+++ b/src/libsystemd/sd-netlink/generic-netlink.c
@@ -0,0 +1,176 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <linux/genetlink.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "generic-netlink.h"
+#include "netlink-internal.h"
+
+typedef struct {
+        const char* name;
+        uint8_t version;
+} genl_family;
+
+static const genl_family genl_families[] = {
+        [SD_GENL_ID_CTRL]   = { .name = "",          .version = 1 },
+        [SD_GENL_WIREGUARD] = { .name = "wireguard", .version = 1 },
+        [SD_GENL_FOU]       = { .name = "fou",       .version = 1 },
+        [SD_GENL_L2TP]      = { .name = "l2tp",      .version = 1 },
+        [SD_GENL_MACSEC]    = { .name = "macsec",    .version = 1 },
+        [SD_GENL_NL80211]   = { .name = "nl80211",   .version = 1 },
+};
+
+int sd_genl_socket_open(sd_netlink **ret) {
+        return netlink_open_family(ret, NETLINK_GENERIC);
+}
+static int lookup_id(sd_netlink *nl, sd_genl_family family, uint16_t *id);
+
+static int genl_message_new(sd_netlink *nl, sd_genl_family family, uint16_t nlmsg_type, uint8_t cmd, sd_netlink_message **ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        const NLType *genl_cmd_type, *nl_type;
+        const NLTypeSystem *type_system;
+        struct genlmsghdr *genl;
+        size_t size;
+        int r;
+
+        assert_return(nl->protocol == NETLINK_GENERIC, -EINVAL);
+
+        r = type_system_get_type(&genl_family_type_system_root, &genl_cmd_type, family);
+        if (r < 0)
+                return r;
+
+        r = message_new_empty(nl, &m);
+        if (r < 0)
+                return r;
+
+        size = NLMSG_SPACE(sizeof(struct genlmsghdr));
+        m->hdr = malloc0(size);
+        if (!m->hdr)
+                return -ENOMEM;
+
+        m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+
+        type_get_type_system(genl_cmd_type, &type_system);
+
+        r = type_system_get_type(type_system, &nl_type, cmd);
+        if (r < 0)
+                return r;
+
+        m->hdr->nlmsg_len = size;
+        m->hdr->nlmsg_type = nlmsg_type;
+
+        type_get_type_system(nl_type, &m->containers[0].type_system);
+        genl = NLMSG_DATA(m->hdr);
+        genl->cmd = cmd;
+        genl->version = genl_families[family].version;
+
+        *ret = TAKE_PTR(m);
+
+        return 0;
+}
+
+int sd_genl_message_new(sd_netlink *nl, sd_genl_family family, uint8_t cmd, sd_netlink_message **ret) {
+        uint16_t id;
+        int r;
+
+        r = lookup_id(nl, family, &id);
+        if (r < 0)
+                return r;
+
+        return genl_message_new(nl, family, id, cmd, ret);
+}
+
+static int lookup_id(sd_netlink *nl, sd_genl_family family, uint16_t *id) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
+        uint16_t u;
+        void *v;
+        int r;
+
+        if (family == SD_GENL_ID_CTRL) {
+                *id = GENL_ID_CTRL;
+                return 0;
+        }
+
+        v = hashmap_get(nl->genl_family_to_nlmsg_type, INT_TO_PTR(family));
+        if (v) {
+                *id = PTR_TO_UINT(v);
+                return 0;
+        }
+
+        r = sd_genl_message_new(nl, SD_GENL_ID_CTRL, CTRL_CMD_GETFAMILY, &req);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_string(req, CTRL_ATTR_FAMILY_NAME, genl_families[family].name);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(nl, req, 0, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_read_u16(reply, CTRL_ATTR_FAMILY_ID, &u);
+        if (r < 0)
+                return r;
+
+        r = hashmap_ensure_allocated(&nl->genl_family_to_nlmsg_type, NULL);
+        if (r < 0)
+                return r;
+
+        r = hashmap_ensure_allocated(&nl->nlmsg_type_to_genl_family, NULL);
+        if (r < 0)
+                return r;
+
+        r = hashmap_put(nl->genl_family_to_nlmsg_type, INT_TO_PTR(family), UINT_TO_PTR(u));
+        if (r < 0)
+                return r;
+
+        r = hashmap_put(nl->nlmsg_type_to_genl_family, UINT_TO_PTR(u), INT_TO_PTR(family));
+        if (r < 0)
+                return r;
+
+        *id = u;
+        return 0;
+}
+
+int nlmsg_type_to_genl_family(const sd_netlink *nl, uint16_t type, sd_genl_family *ret) {
+        void *p;
+
+        assert_return(nl, -EINVAL);
+        assert_return(nl->protocol == NETLINK_GENERIC, -EINVAL);
+        assert(ret);
+
+        if (type == NLMSG_ERROR)
+                *ret = SD_GENL_ERROR;
+        else if (type == NLMSG_DONE)
+                *ret = SD_GENL_DONE;
+        else if (type == GENL_ID_CTRL)
+                *ret = SD_GENL_ID_CTRL;
+        else {
+                p = hashmap_get(nl->nlmsg_type_to_genl_family, UINT_TO_PTR(type));
+                if (!p)
+                        return -EOPNOTSUPP;
+
+                *ret = PTR_TO_INT(p);
+        }
+
+        return 0;
+}
+
+int sd_genl_message_get_family(const sd_netlink *nl, const sd_netlink_message *m, sd_genl_family *family) {
+        uint16_t type;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(nl, -EINVAL);
+        assert_return(nl->protocol == NETLINK_GENERIC, -EINVAL);
+        assert_return(family, -EINVAL);
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return r;
+
+        return nlmsg_type_to_genl_family(nl, type, family);
+}
diff --git a/src/libsystemd/sd-netlink/generic-netlink.h b/src/libsystemd/sd-netlink/generic-netlink.h
new file mode 100644
index 0000000..72001e8
--- /dev/null
+++ b/src/libsystemd/sd-netlink/generic-netlink.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-netlink.h"
+
+int nlmsg_type_to_genl_family(const sd_netlink *nl, uint16_t type, sd_genl_family *ret);
diff --git a/src/libsystemd/sd-netlink/netlink-internal.h b/src/libsystemd/sd-netlink/netlink-internal.h
new file mode 100644
index 0000000..1240f0d
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-internal.h
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <linux/netlink.h>
+
+#include "sd-netlink.h"
+
+#include "list.h"
+#include "netlink-types.h"
+#include "prioq.h"
+#include "time-util.h"
+
+#define RTNL_DEFAULT_TIMEOUT ((usec_t) (25 * USEC_PER_SEC))
+
+#define RTNL_RQUEUE_MAX 64*1024
+
+#define RTNL_CONTAINER_DEPTH 32
+
+struct reply_callback {
+        sd_netlink_message_handler_t callback;
+        usec_t timeout;
+        uint64_t serial;
+        unsigned prioq_idx;
+};
+
+struct match_callback {
+        sd_netlink_message_handler_t callback;
+        uint16_t type;
+
+        LIST_FIELDS(struct match_callback, match_callbacks);
+};
+
+typedef enum NetlinkSlotType {
+        NETLINK_REPLY_CALLBACK,
+        NETLINK_MATCH_CALLBACK,
+        _NETLINK_SLOT_INVALID = -1,
+} NetlinkSlotType;
+
+struct sd_netlink_slot {
+        unsigned n_ref;
+        sd_netlink *netlink;
+        void *userdata;
+        sd_netlink_destroy_t destroy_callback;
+        NetlinkSlotType type:2;
+
+        bool floating:1;
+        char *description;
+
+        LIST_FIELDS(sd_netlink_slot, slots);
+
+        union {
+                struct reply_callback reply_callback;
+                struct match_callback match_callback;
+        };
+};
+
+struct sd_netlink {
+        unsigned n_ref;
+
+        int fd;
+
+        union {
+                struct sockaddr sa;
+                struct sockaddr_nl nl;
+        } sockaddr;
+
+        int protocol;
+
+        Hashmap *broadcast_group_refs;
+        bool broadcast_group_dont_leave:1; /* until we can rely on 4.2 */
+
+        sd_netlink_message **rqueue;
+        unsigned rqueue_size;
+        size_t rqueue_allocated;
+
+        sd_netlink_message **rqueue_partial;
+        unsigned rqueue_partial_size;
+        size_t rqueue_partial_allocated;
+
+        struct nlmsghdr *rbuffer;
+        size_t rbuffer_allocated;
+
+        bool processing:1;
+
+        uint32_t serial;
+
+        struct Prioq *reply_callbacks_prioq;
+        Hashmap *reply_callbacks;
+
+        LIST_HEAD(struct match_callback, match_callbacks);
+
+        LIST_HEAD(sd_netlink_slot, slots);
+
+        pid_t original_pid;
+
+        sd_event_source *io_event_source;
+        sd_event_source *time_event_source;
+        sd_event_source *exit_event_source;
+        sd_event *event;
+
+        Hashmap *genl_family_to_nlmsg_type;
+        Hashmap *nlmsg_type_to_genl_family;
+};
+
+struct netlink_attribute {
+        size_t offset; /* offset from hdr to attribute */
+        bool nested:1;
+        bool net_byteorder:1;
+};
+
+struct netlink_container {
+        const struct NLTypeSystem *type_system; /* the type system of the container */
+        size_t offset; /* offset from hdr to the start of the container */
+        struct netlink_attribute *attributes;
+        unsigned short n_attributes; /* number of attributes in container */
+};
+
+struct sd_netlink_message {
+        unsigned n_ref;
+
+        int protocol;
+
+        struct nlmsghdr *hdr;
+        struct netlink_container containers[RTNL_CONTAINER_DEPTH];
+        unsigned n_containers; /* number of containers */
+        bool sealed:1;
+        bool broadcast:1;
+
+        sd_netlink_message *next; /* next in a chain of multi-part messages */
+};
+
+int message_new(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t type);
+int message_new_empty(sd_netlink *rtnl, sd_netlink_message **ret);
+
+int netlink_open_family(sd_netlink **ret, int family);
+
+int socket_open(int family);
+int socket_bind(sd_netlink *nl);
+int socket_broadcast_group_ref(sd_netlink *nl, unsigned group);
+int socket_broadcast_group_unref(sd_netlink *nl, unsigned group);
+int socket_write_message(sd_netlink *nl, sd_netlink_message *m);
+int socket_read_message(sd_netlink *nl);
+
+int rtnl_rqueue_make_room(sd_netlink *rtnl);
+int rtnl_rqueue_partial_make_room(sd_netlink *rtnl);
+
+/* Make sure callbacks don't destroy the rtnl connection */
+#define NETLINK_DONT_DESTROY(rtnl) \
+        _cleanup_(sd_netlink_unrefp) _unused_ sd_netlink *_dont_destroy_##rtnl = sd_netlink_ref(rtnl)
diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c
new file mode 100644
index 0000000..bd56536
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-message.c
@@ -0,0 +1,1320 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <netinet/in.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "format-util.h"
+#include "memory-util.h"
+#include "netlink-internal.h"
+#include "netlink-types.h"
+#include "netlink-util.h"
+#include "socket-util.h"
+#include "strv.h"
+
+#define GET_CONTAINER(m, i) ((struct rtattr*)((uint8_t*)(m)->hdr + (m)->containers[i].offset))
+
+#define RTA_TYPE(rta) ((rta)->rta_type & NLA_TYPE_MASK)
+#define RTA_FLAGS(rta) ((rta)->rta_type & ~NLA_TYPE_MASK)
+
+int message_new_empty(sd_netlink *rtnl, sd_netlink_message **ret) {
+        sd_netlink_message *m;
+
+        assert_return(ret, -EINVAL);
+
+        /* Note that 'rtnl' is currently unused, if we start using it internally
+           we must take care to avoid problems due to mutual references between
+           buses and their queued messages. See sd-bus.
+         */
+
+        m = new(sd_netlink_message, 1);
+        if (!m)
+                return -ENOMEM;
+
+        *m = (sd_netlink_message) {
+                .n_ref = 1,
+                .protocol = rtnl->protocol,
+                .sealed = false,
+        };
+
+        *ret = m;
+
+        return 0;
+}
+
+int message_new(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t type) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        const NLType *nl_type;
+        size_t size;
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+
+        r = type_system_root_get_type(rtnl, &nl_type, type);
+        if (r < 0)
+                return r;
+
+        if (type_get_type(nl_type) != NETLINK_TYPE_NESTED)
+                return -EINVAL;
+
+        r = message_new_empty(rtnl, &m);
+        if (r < 0)
+                return r;
+
+        size = NLMSG_SPACE(type_get_size(nl_type));
+
+        assert(size >= sizeof(struct nlmsghdr));
+        m->hdr = malloc0(size);
+        if (!m->hdr)
+                return -ENOMEM;
+
+        m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+
+        type_get_type_system(nl_type, &m->containers[0].type_system);
+        m->hdr->nlmsg_len = size;
+        m->hdr->nlmsg_type = type;
+
+        *ret = TAKE_PTR(m);
+
+        return 0;
+}
+
+int sd_netlink_message_request_dump(sd_netlink_message *m, int dump) {
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+
+        assert_return(IN_SET(m->hdr->nlmsg_type,
+                             RTM_GETLINK, RTM_GETLINKPROP, RTM_GETADDR, RTM_GETROUTE, RTM_GETNEIGH,
+                             RTM_GETRULE, RTM_GETADDRLABEL, RTM_GETNEXTHOP), -EINVAL);
+
+        SET_FLAG(m->hdr->nlmsg_flags, NLM_F_DUMP, dump);
+
+        return 0;
+}
+
+DEFINE_TRIVIAL_REF_FUNC(sd_netlink_message, sd_netlink_message);
+
+sd_netlink_message *sd_netlink_message_unref(sd_netlink_message *m) {
+        while (m && --m->n_ref == 0) {
+                unsigned i;
+
+                free(m->hdr);
+
+                for (i = 0; i <= m->n_containers; i++)
+                        free(m->containers[i].attributes);
+
+                sd_netlink_message *t = m;
+                m = m->next;
+                free(t);
+        }
+
+        return NULL;
+}
+
+int sd_netlink_message_get_type(const sd_netlink_message *m, uint16_t *type) {
+        assert_return(m, -EINVAL);
+        assert_return(type, -EINVAL);
+
+        *type = m->hdr->nlmsg_type;
+
+        return 0;
+}
+
+int sd_netlink_message_set_flags(sd_netlink_message *m, uint16_t flags) {
+        assert_return(m, -EINVAL);
+        assert_return(flags, -EINVAL);
+
+        m->hdr->nlmsg_flags = flags;
+
+        return 0;
+}
+
+int sd_netlink_message_is_broadcast(const sd_netlink_message *m) {
+        assert_return(m, -EINVAL);
+
+        return m->broadcast;
+}
+
+/* If successful the updated message will be correctly aligned, if
+   unsuccessful the old message is untouched. */
+static int add_rtattr(sd_netlink_message *m, unsigned short type, const void *data, size_t data_length) {
+        size_t message_length;
+        struct nlmsghdr *new_hdr;
+        struct rtattr *rta;
+        unsigned i;
+        int offset;
+
+        assert(m);
+        assert(m->hdr);
+        assert(!m->sealed);
+        assert(NLMSG_ALIGN(m->hdr->nlmsg_len) == m->hdr->nlmsg_len);
+        assert(!data || data_length > 0);
+
+        /* get the new message size (with padding at the end) */
+        message_length = m->hdr->nlmsg_len + RTA_SPACE(data_length);
+
+        /* buffer should be smaller than both one page or 8K to be accepted by the kernel */
+        if (message_length > MIN(page_size(), 8192UL))
+                return -ENOBUFS;
+
+        /* realloc to fit the new attribute */
+        new_hdr = realloc(m->hdr, message_length);
+        if (!new_hdr)
+                return -ENOMEM;
+        m->hdr = new_hdr;
+
+        /* get pointer to the attribute we are about to add */
+        rta = (struct rtattr *) ((uint8_t *) m->hdr + m->hdr->nlmsg_len);
+
+        rtattr_append_attribute_internal(rta, type, data, data_length);
+
+        /* if we are inside containers, extend them */
+        for (i = 0; i < m->n_containers; i++)
+                GET_CONTAINER(m, i)->rta_len += RTA_SPACE(data_length);
+
+        /* update message size */
+        offset = m->hdr->nlmsg_len;
+        m->hdr->nlmsg_len = message_length;
+
+        /* return old message size */
+        return offset;
+}
+
+static int message_attribute_has_type(sd_netlink_message *m, size_t *out_size, uint16_t attribute_type, uint16_t data_type) {
+        const NLType *type;
+        int r;
+
+        assert(m);
+
+        r = type_system_get_type(m->containers[m->n_containers].type_system, &type, attribute_type);
+        if (r < 0)
+                return r;
+
+        if (type_get_type(type) != data_type)
+                return -EINVAL;
+
+        if (out_size)
+                *out_size = type_get_size(type);
+        return 0;
+}
+
+int sd_netlink_message_append_string(sd_netlink_message *m, unsigned short type, const char *data) {
+        size_t length, size;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+
+        r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_STRING);
+        if (r < 0)
+                return r;
+
+        if (size) {
+                length = strnlen(data, size+1);
+                if (length > size)
+                        return -EINVAL;
+        } else
+                length = strlen(data);
+
+        r = add_rtattr(m, type, data, length + 1);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_strv(sd_netlink_message *m, unsigned short type, char * const *data) {
+        size_t length, size;
+        char * const *p;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+
+        r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_STRING);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(p, data) {
+                if (size) {
+                        length = strnlen(*p, size+1);
+                        if (length > size)
+                                return -EINVAL;
+                } else
+                        length = strlen(*p);
+
+                r = add_rtattr(m, type, *p, length + 1);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int sd_netlink_message_append_flag(sd_netlink_message *m, unsigned short type) {
+        size_t size;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_FLAG);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, NULL, 0);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_u8(sd_netlink_message *m, unsigned short type, uint8_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U8);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(uint8_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_u16(sd_netlink_message *m, unsigned short type, uint16_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U16);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(uint16_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_u32(sd_netlink_message *m, unsigned short type, uint32_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U32);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(uint32_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_u64(sd_netlink_message *m, unsigned short type, uint64_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U64);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(uint64_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_s8(sd_netlink_message *m, unsigned short type, int8_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_S8);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(int8_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_s16(sd_netlink_message *m, unsigned short type, int16_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_S16);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(int16_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_s32(sd_netlink_message *m, unsigned short type, int32_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_S32);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(int32_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_s64(sd_netlink_message *m, unsigned short type, int64_t data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_S64);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, &data, sizeof(int64_t));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_data(sd_netlink_message *m, unsigned short type, const void *data, size_t len) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+
+        r = add_rtattr(m, type, data, len);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int netlink_message_append_in_addr_union(sd_netlink_message *m, unsigned short type, int family, const union in_addr_union *data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+        assert_return(IN_SET(family, AF_INET, AF_INET6), -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_IN_ADDR);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, data, FAMILY_ADDRESS_SIZE(family));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_in_addr(sd_netlink_message *m, unsigned short type, const struct in_addr *data) {
+        return netlink_message_append_in_addr_union(m, type, AF_INET, (const union in_addr_union *) data);
+}
+
+int sd_netlink_message_append_in6_addr(sd_netlink_message *m, unsigned short type, const struct in6_addr *data) {
+        return netlink_message_append_in_addr_union(m, type, AF_INET6, (const union in_addr_union *) data);
+}
+
+int netlink_message_append_sockaddr_union(sd_netlink_message *m, unsigned short type, const union sockaddr_union *data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+        assert_return(IN_SET(data->sa.sa_family, AF_INET, AF_INET6), -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_SOCKADDR);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, data, data->sa.sa_family == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_sockaddr_in(sd_netlink_message *m, unsigned short type, const struct sockaddr_in *data) {
+        return netlink_message_append_sockaddr_union(m, type, (const union sockaddr_union *) data);
+}
+
+int sd_netlink_message_append_sockaddr_in6(sd_netlink_message *m, unsigned short type, const struct sockaddr_in6 *data) {
+        return netlink_message_append_sockaddr_union(m, type, (const union sockaddr_union *) data);
+}
+
+int sd_netlink_message_append_ether_addr(sd_netlink_message *m, unsigned short type, const struct ether_addr *data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_ETHER_ADDR);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, data, ETH_ALEN);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int netlink_message_append_hw_addr(sd_netlink_message *m, unsigned short type, const hw_addr_data *data) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+        assert_return(data->length > 0, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_ETHER_ADDR);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, data->addr.bytes, data->length);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_append_cache_info(sd_netlink_message *m, unsigned short type, const struct ifa_cacheinfo *info) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(info, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_CACHE_INFO);
+        if (r < 0)
+                return r;
+
+        r = add_rtattr(m, type, info, sizeof(struct ifa_cacheinfo));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int sd_netlink_message_open_container(sd_netlink_message *m, unsigned short type) {
+        size_t size;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        /* m->containers[m->n_containers + 1] is accessed both in read and write. Prevent access out of bound */
+        assert_return(m->n_containers < (RTNL_CONTAINER_DEPTH - 1), -ERANGE);
+
+        r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_NESTED);
+        if (r < 0) {
+                const NLTypeSystemUnion *type_system_union;
+                int family;
+
+                r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_UNION);
+                if (r < 0)
+                        return r;
+
+                r = sd_rtnl_message_get_family(m, &family);
+                if (r < 0)
+                        return r;
+
+                r = type_system_get_type_system_union(m->containers[m->n_containers].type_system, &type_system_union, type);
+                if (r < 0)
+                        return r;
+
+                r = type_system_union_protocol_get_type_system(type_system_union,
+                                                               &m->containers[m->n_containers + 1].type_system,
+                                                               family);
+                if (r < 0)
+                        return r;
+        } else {
+                r = type_system_get_type_system(m->containers[m->n_containers].type_system,
+                                                &m->containers[m->n_containers + 1].type_system,
+                                                type);
+                if (r < 0)
+                        return r;
+        }
+
+        r = add_rtattr(m, type | NLA_F_NESTED, NULL, size);
+        if (r < 0)
+                return r;
+
+        m->containers[m->n_containers++].offset = r;
+
+        return 0;
+}
+
+int sd_netlink_message_open_container_union(sd_netlink_message *m, unsigned short type, const char *key) {
+        const NLTypeSystemUnion *type_system_union;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->n_containers < (RTNL_CONTAINER_DEPTH - 1), -ERANGE);
+
+        r = type_system_get_type_system_union(m->containers[m->n_containers].type_system, &type_system_union, type);
+        if (r < 0)
+                return r;
+
+        r = type_system_union_get_type_system(type_system_union,
+                                              &m->containers[m->n_containers + 1].type_system,
+                                              key);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_string(m, type_system_union->match, key);
+        if (r < 0)
+                return r;
+
+        /* do we ever need non-null size */
+        r = add_rtattr(m, type | NLA_F_NESTED, NULL, 0);
+        if (r < 0)
+                return r;
+
+        m->containers[m->n_containers++].offset = r;
+
+        return 0;
+}
+
+int sd_netlink_message_close_container(sd_netlink_message *m) {
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->n_containers > 0, -EINVAL);
+
+        m->containers[m->n_containers].type_system = NULL;
+        m->containers[m->n_containers].offset = 0;
+        m->n_containers--;
+
+        return 0;
+}
+
+int sd_netlink_message_open_array(sd_netlink_message *m, uint16_t type) {
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->n_containers < (RTNL_CONTAINER_DEPTH - 1), -ERANGE);
+
+        r = add_rtattr(m, type | NLA_F_NESTED, NULL, 0);
+        if (r < 0)
+                return r;
+
+        m->containers[m->n_containers].offset = r;
+        m->n_containers++;
+        m->containers[m->n_containers].type_system = m->containers[m->n_containers - 1].type_system;
+
+        return 0;
+}
+
+int sd_netlink_message_cancel_array(sd_netlink_message *m) {
+        unsigned i;
+        uint32_t rta_len;
+
+        assert_return(m, -EINVAL);
+        assert_return(!m->sealed, -EPERM);
+        assert_return(m->n_containers > 1, -EINVAL);
+
+        rta_len = GET_CONTAINER(m, (m->n_containers - 1))->rta_len;
+
+        for (i = 0; i < m->n_containers; i++)
+                GET_CONTAINER(m, i)->rta_len -= rta_len;
+
+        m->hdr->nlmsg_len -= rta_len;
+
+        m->n_containers--;
+        m->containers[m->n_containers].type_system = NULL;
+
+        return 0;
+}
+
+static int netlink_message_read_internal(sd_netlink_message *m, unsigned short type, void **data, bool *net_byteorder) {
+        struct netlink_attribute *attribute;
+        struct rtattr *rta;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EPERM);
+        assert_return(data, -EINVAL);
+
+        assert(m->n_containers < RTNL_CONTAINER_DEPTH);
+
+        if (!m->containers[m->n_containers].attributes)
+                return -ENODATA;
+
+        if (type >= m->containers[m->n_containers].n_attributes)
+                return -ENODATA;
+
+        attribute = &m->containers[m->n_containers].attributes[type];
+
+        if (attribute->offset == 0)
+                return -ENODATA;
+
+        rta = (struct rtattr*)((uint8_t *) m->hdr + attribute->offset);
+
+        *data = RTA_DATA(rta);
+
+        if (net_byteorder)
+                *net_byteorder = attribute->net_byteorder;
+
+        return RTA_PAYLOAD(rta);
+}
+
+int sd_netlink_message_read(sd_netlink_message *m, unsigned short type, size_t size, void *data) {
+        void *attr_data;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+
+        if ((size_t) r < size)
+                return -EIO;
+
+        if (data)
+                memcpy(data, attr_data, size);
+
+        return r;
+}
+
+int sd_netlink_message_read_data(sd_netlink_message *m, unsigned short type, size_t *ret_size, void **ret_data) {
+        void *attr_data, *data;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+
+        if (ret_data) {
+                data = memdup(attr_data, r);
+                if (!data)
+                        return -ENOMEM;
+
+                *ret_data = data;
+        }
+
+        if (ret_size)
+                *ret_size = r;
+
+        return r;
+}
+
+int sd_netlink_message_read_string_strdup(sd_netlink_message *m, unsigned short type, char **data) {
+        void *attr_data;
+        char *str;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_STRING);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+
+        if (data) {
+                str = strndup(attr_data, r);
+                if (!str)
+                        return -ENOMEM;
+
+                *data = str;
+        }
+
+        return 0;
+}
+
+int sd_netlink_message_read_string(sd_netlink_message *m, unsigned short type, const char **data) {
+        int r;
+        void *attr_data;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_STRING);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+        else if (strnlen(attr_data, r) >= (size_t) r)
+                return -EIO;
+
+        if (data)
+                *data = (const char *) attr_data;
+
+        return 0;
+}
+
+int sd_netlink_message_read_u8(sd_netlink_message *m, unsigned short type, uint8_t *data) {
+        int r;
+        void *attr_data;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U8);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+        else if ((size_t) r < sizeof(uint8_t))
+                return -EIO;
+
+        if (data)
+                *data = *(uint8_t *) attr_data;
+
+        return 0;
+}
+
+int sd_netlink_message_read_u16(sd_netlink_message *m, unsigned short type, uint16_t *data) {
+        void *attr_data;
+        bool net_byteorder;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U16);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, &net_byteorder);
+        if (r < 0)
+                return r;
+        else if ((size_t) r < sizeof(uint16_t))
+                return -EIO;
+
+        if (data) {
+                if (net_byteorder)
+                        *data = be16toh(*(uint16_t *) attr_data);
+                else
+                        *data = *(uint16_t *) attr_data;
+        }
+
+        return 0;
+}
+
+int sd_netlink_message_read_u32(sd_netlink_message *m, unsigned short type, uint32_t *data) {
+        void *attr_data;
+        bool net_byteorder;
+        int r;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U32);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, &net_byteorder);
+        if (r < 0)
+                return r;
+        else if ((size_t) r < sizeof(uint32_t))
+                return -EIO;
+
+        if (data) {
+                if (net_byteorder)
+                        *data = be32toh(*(uint32_t *) attr_data);
+                else
+                        *data = *(uint32_t *) attr_data;
+        }
+
+        return 0;
+}
+
+int sd_netlink_message_read_ether_addr(sd_netlink_message *m, unsigned short type, struct ether_addr *data) {
+        int r;
+        void *attr_data;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_ETHER_ADDR);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+        else if ((size_t) r < sizeof(struct ether_addr))
+                return -EIO;
+
+        if (data)
+                memcpy(data, attr_data, sizeof(struct ether_addr));
+
+        return 0;
+}
+
+int netlink_message_read_hw_addr(sd_netlink_message *m, unsigned short type, hw_addr_data *data) {
+        int r;
+        void *attr_data;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_ETHER_ADDR);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+        else if ((size_t) r > sizeof(union hw_addr_union))
+                return -EIO;
+
+        if (data) {
+                memcpy(data->addr.bytes, attr_data, r);
+                data->length = r;
+        }
+
+        return 0;
+}
+
+int sd_netlink_message_read_cache_info(sd_netlink_message *m, unsigned short type, struct ifa_cacheinfo *info) {
+        int r;
+        void *attr_data;
+
+        assert_return(m, -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_CACHE_INFO);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+        else if ((size_t) r < sizeof(struct ifa_cacheinfo))
+                return -EIO;
+
+        if (info)
+                memcpy(info, attr_data, sizeof(struct ifa_cacheinfo));
+
+        return 0;
+}
+
+int netlink_message_read_in_addr_union(sd_netlink_message *m, unsigned short type, int family, union in_addr_union *data) {
+        void *attr_data;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(IN_SET(family, AF_INET, AF_INET6), -EINVAL);
+
+        r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_IN_ADDR);
+        if (r < 0)
+                return r;
+
+        r = netlink_message_read_internal(m, type, &attr_data, NULL);
+        if (r < 0)
+                return r;
+        else if ((size_t) r < FAMILY_ADDRESS_SIZE(family))
+                return -EIO;
+
+        if (data)
+                memcpy(data, attr_data, FAMILY_ADDRESS_SIZE(family));
+
+        return 0;
+}
+
+int sd_netlink_message_read_in_addr(sd_netlink_message *m, unsigned short type, struct in_addr *data) {
+        union in_addr_union u;
+        int r;
+
+        r = netlink_message_read_in_addr_union(m, type, AF_INET, &u);
+        if (r >= 0 && data)
+                *data = u.in;
+
+        return r;
+}
+
+int sd_netlink_message_read_in6_addr(sd_netlink_message *m, unsigned short type, struct in6_addr *data) {
+        union in_addr_union u;
+        int r;
+
+        r = netlink_message_read_in_addr_union(m, type, AF_INET6, &u);
+        if (r >= 0 && data)
+                *data = u.in6;
+
+        return r;
+}
+
+int sd_netlink_message_read_strv(sd_netlink_message *m, unsigned short container_type, unsigned short type_id, char ***ret) {
+        _cleanup_strv_free_ char **s = NULL;
+        const NLTypeSystem *type_system;
+        const NLType *nl_type;
+        struct rtattr *rta;
+        void *container;
+        size_t rt_len;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -EINVAL);
+
+        r = type_system_get_type(m->containers[m->n_containers].type_system,
+                                 &nl_type,
+                                 container_type);
+        if (r < 0)
+                return r;
+
+        if (type_get_type(nl_type) != NETLINK_TYPE_NESTED)
+                return -EINVAL;
+
+        r = type_system_get_type_system(m->containers[m->n_containers].type_system,
+                                        &type_system,
+                                        container_type);
+        if (r < 0)
+                return r;
+
+        r = type_system_get_type(type_system, &nl_type, type_id);
+        if (r < 0)
+                return r;
+
+        if (type_get_type(nl_type) != NETLINK_TYPE_STRING)
+                return -EINVAL;
+
+        r = netlink_message_read_internal(m, container_type, &container, NULL);
+        if (r < 0)
+                return r;
+
+        rt_len = (size_t) r;
+        rta = container;
+
+        /* RTA_OK() macro compares with rta->rt_len, which is unsigned short, and
+         * LGTM.com analysis does not like the type difference. Hence, here we
+         * introduce an unsigned short variable as a workaround. */
+        unsigned short len = rt_len;
+        for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
+                unsigned short type;
+
+                type = RTA_TYPE(rta);
+                if (type != type_id)
+                        continue;
+
+                r = strv_extend(&s, RTA_DATA(rta));
+                if (r < 0)
+                        return r;
+        }
+
+        *ret = TAKE_PTR(s);
+        return 0;
+}
+
+static int netlink_container_parse(sd_netlink_message *m,
+                                   struct netlink_container *container,
+                                   struct rtattr *rta,
+                                   size_t rt_len) {
+        _cleanup_free_ struct netlink_attribute *attributes = NULL;
+        size_t n_allocated = 0;
+
+        /* RTA_OK() macro compares with rta->rt_len, which is unsigned short, and
+         * LGTM.com analysis does not like the type difference. Hence, here we
+         * introduce an unsigned short variable as a workaround. */
+        unsigned short len = rt_len;
+        for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
+                unsigned short type;
+
+                type = RTA_TYPE(rta);
+
+                if (!GREEDY_REALLOC0(attributes, n_allocated, type + 1))
+                        return -ENOMEM;
+
+                if (attributes[type].offset != 0)
+                        log_debug("rtnl: message parse - overwriting repeated attribute");
+
+                attributes[type].offset = (uint8_t *) rta - (uint8_t *) m->hdr;
+                attributes[type].nested = RTA_FLAGS(rta) & NLA_F_NESTED;
+                attributes[type].net_byteorder = RTA_FLAGS(rta) & NLA_F_NET_BYTEORDER;
+        }
+
+        container->attributes = TAKE_PTR(attributes);
+        container->n_attributes = n_allocated;
+
+        return 0;
+}
+
+int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short type_id) {
+        const NLType *nl_type;
+        const NLTypeSystem *type_system;
+        void *container;
+        uint16_t type;
+        size_t size;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->n_containers < (RTNL_CONTAINER_DEPTH - 1), -EINVAL);
+
+        r = type_system_get_type(m->containers[m->n_containers].type_system,
+                                 &nl_type,
+                                 type_id);
+        if (r < 0)
+                return r;
+
+        type = type_get_type(nl_type);
+
+        if (type == NETLINK_TYPE_NESTED) {
+                r = type_system_get_type_system(m->containers[m->n_containers].type_system,
+                                                &type_system,
+                                                type_id);
+                if (r < 0)
+                        return r;
+        } else if (type == NETLINK_TYPE_UNION) {
+                const NLTypeSystemUnion *type_system_union;
+
+                r = type_system_get_type_system_union(m->containers[m->n_containers].type_system,
+                                                      &type_system_union,
+                                                      type_id);
+                if (r < 0)
+                        return r;
+
+                switch (type_system_union->match_type) {
+                case NL_MATCH_SIBLING:
+                {
+                        const char *key;
+
+                        r = sd_netlink_message_read_string(m, type_system_union->match, &key);
+                        if (r < 0)
+                                return r;
+
+                        r = type_system_union_get_type_system(type_system_union,
+                                                              &type_system,
+                                                              key);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                }
+                case NL_MATCH_PROTOCOL:
+                {
+                        int family;
+
+                        r = sd_rtnl_message_get_family(m, &family);
+                        if (r < 0)
+                                return r;
+
+                        r = type_system_union_protocol_get_type_system(type_system_union,
+                                                                       &type_system,
+                                                                       family);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                }
+                default:
+                        assert_not_reached("sd-netlink: invalid type system union type");
+                }
+        } else
+                return -EINVAL;
+
+        r = netlink_message_read_internal(m, type_id, &container, NULL);
+        if (r < 0)
+                return r;
+
+        size = (size_t) r;
+        m->n_containers++;
+
+        r = netlink_container_parse(m,
+                                    &m->containers[m->n_containers],
+                                    container,
+                                    size);
+        if (r < 0) {
+                m->n_containers--;
+                return r;
+        }
+
+        m->containers[m->n_containers].type_system = type_system;
+
+        return 0;
+}
+
+int sd_netlink_message_enter_array(sd_netlink_message *m, unsigned short type_id) {
+        void *container;
+        size_t size;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->n_containers < (RTNL_CONTAINER_DEPTH - 1), -EINVAL);
+
+        r = netlink_message_read_internal(m, type_id, &container, NULL);
+        if (r < 0)
+                return r;
+
+        size = (size_t) r;
+        m->n_containers++;
+
+        r = netlink_container_parse(m,
+                                    &m->containers[m->n_containers],
+                                    container,
+                                    size);
+        if (r < 0) {
+                m->n_containers--;
+                return r;
+        }
+
+        m->containers[m->n_containers].type_system = m->containers[m->n_containers - 1].type_system;
+
+        return 0;
+}
+
+int sd_netlink_message_exit_container(sd_netlink_message *m) {
+        assert_return(m, -EINVAL);
+        assert_return(m->sealed, -EINVAL);
+        assert_return(m->n_containers > 0, -EINVAL);
+
+        m->containers[m->n_containers].attributes = mfree(m->containers[m->n_containers].attributes);
+        m->containers[m->n_containers].type_system = NULL;
+
+        m->n_containers--;
+
+        return 0;
+}
+
+uint32_t rtnl_message_get_serial(sd_netlink_message *m) {
+        assert(m);
+        assert(m->hdr);
+
+        return m->hdr->nlmsg_seq;
+}
+
+int sd_netlink_message_is_error(const sd_netlink_message *m) {
+        assert_return(m, 0);
+        assert_return(m->hdr, 0);
+
+        return m->hdr->nlmsg_type == NLMSG_ERROR;
+}
+
+int sd_netlink_message_get_errno(const sd_netlink_message *m) {
+        struct nlmsgerr *err;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+
+        if (!sd_netlink_message_is_error(m))
+                return 0;
+
+        err = NLMSG_DATA(m->hdr);
+
+        return err->error;
+}
+
+static int netlink_message_parse_error(sd_netlink_message *m) {
+        struct nlmsgerr *err = NLMSG_DATA(m->hdr);
+        size_t hlen = sizeof(struct nlmsgerr);
+
+        /* no TLVs, nothing to do here */
+        if (!(m->hdr->nlmsg_flags & NLM_F_ACK_TLVS))
+                return 0;
+
+        /* if NLM_F_CAPPED is set then the inner err msg was capped */
+        if (!(m->hdr->nlmsg_flags & NLM_F_CAPPED))
+                hlen += err->msg.nlmsg_len - sizeof(struct nlmsghdr);
+
+        if (m->hdr->nlmsg_len <= NLMSG_SPACE(hlen))
+                return 0;
+
+        return netlink_container_parse(m,
+                                       &m->containers[m->n_containers],
+                                       (struct rtattr*)((uint8_t*) NLMSG_DATA(m->hdr) + hlen),
+                                       NLMSG_PAYLOAD(m->hdr, hlen));
+}
+
+int sd_netlink_message_rewind(sd_netlink_message *m, sd_netlink *genl) {
+        const NLType *nl_type;
+        uint16_t type;
+        size_t size;
+        unsigned i;
+        int r;
+
+        assert_return(m, -EINVAL);
+        assert_return(genl || m->protocol != NETLINK_GENERIC, -EINVAL);
+
+        /* don't allow appending to message once parsed */
+        if (!m->sealed)
+                rtnl_message_seal(m);
+
+        for (i = 1; i <= m->n_containers; i++)
+                m->containers[i].attributes = mfree(m->containers[i].attributes);
+
+        m->n_containers = 0;
+
+        if (m->containers[0].attributes)
+                /* top-level attributes have already been parsed */
+                return 0;
+
+        assert(m->hdr);
+
+        r = type_system_root_get_type(genl, &nl_type, m->hdr->nlmsg_type);
+        if (r < 0)
+                return r;
+
+        type = type_get_type(nl_type);
+        size = type_get_size(nl_type);
+
+        if (type == NETLINK_TYPE_NESTED) {
+                const NLTypeSystem *type_system;
+
+                type_get_type_system(nl_type, &type_system);
+
+                m->containers[0].type_system = type_system;
+
+                if (sd_netlink_message_is_error(m))
+                        r = netlink_message_parse_error(m);
+                else
+                        r = netlink_container_parse(m,
+                                                    &m->containers[m->n_containers],
+                                                    (struct rtattr*)((uint8_t*) NLMSG_DATA(m->hdr) + NLMSG_ALIGN(size)),
+                                                    NLMSG_PAYLOAD(m->hdr, size));
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+void rtnl_message_seal(sd_netlink_message *m) {
+        assert(m);
+        assert(!m->sealed);
+
+        m->sealed = true;
+}
+
+sd_netlink_message *sd_netlink_message_next(sd_netlink_message *m) {
+        assert_return(m, NULL);
+
+        return m->next;
+}
diff --git a/src/libsystemd/sd-netlink/netlink-slot.c b/src/libsystemd/sd-netlink/netlink-slot.c
new file mode 100644
index 0000000..fa951bf
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-slot.c
@@ -0,0 +1,202 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "netlink-internal.h"
+#include "netlink-slot.h"
+#include "string-util.h"
+
+int netlink_slot_allocate(
+                sd_netlink *nl,
+                bool floating,
+                NetlinkSlotType type,
+                size_t extra,
+                void *userdata,
+                const char *description,
+                sd_netlink_slot **ret) {
+
+        _cleanup_free_ sd_netlink_slot *slot = NULL;
+
+        assert(nl);
+        assert(ret);
+
+        slot = malloc0(offsetof(sd_netlink_slot, reply_callback) + extra);
+        if (!slot)
+                return -ENOMEM;
+
+        slot->n_ref = 1;
+        slot->netlink = nl;
+        slot->userdata = userdata;
+        slot->type = type;
+        slot->floating = floating;
+
+        if (description) {
+                slot->description = strdup(description);
+                if (!slot->description)
+                        return -ENOMEM;
+        }
+
+        if (!floating)
+                sd_netlink_ref(nl);
+
+        LIST_PREPEND(slots, nl->slots, slot);
+
+        *ret = TAKE_PTR(slot);
+
+        return 0;
+}
+
+void netlink_slot_disconnect(sd_netlink_slot *slot, bool unref) {
+        sd_netlink *nl;
+
+        assert(slot);
+
+        nl = slot->netlink;
+        if (!nl)
+                return;
+
+        switch (slot->type) {
+
+        case NETLINK_REPLY_CALLBACK:
+                (void) hashmap_remove(nl->reply_callbacks, &slot->reply_callback.serial);
+
+                if (slot->reply_callback.timeout != 0)
+                        prioq_remove(nl->reply_callbacks_prioq, &slot->reply_callback, &slot->reply_callback.prioq_idx);
+
+                break;
+        case NETLINK_MATCH_CALLBACK:
+                LIST_REMOVE(match_callbacks, nl->match_callbacks, &slot->match_callback);
+
+                switch (slot->match_callback.type) {
+                case RTM_NEWLINK:
+                case RTM_DELLINK:
+                        (void) socket_broadcast_group_unref(nl, RTNLGRP_LINK);
+
+                        break;
+                case RTM_NEWADDR:
+                case RTM_DELADDR:
+                        (void) socket_broadcast_group_unref(nl, RTNLGRP_IPV4_IFADDR);
+                        (void) socket_broadcast_group_unref(nl, RTNLGRP_IPV6_IFADDR);
+
+                        break;
+                case RTM_NEWROUTE:
+                case RTM_DELROUTE:
+                        (void) socket_broadcast_group_unref(nl, RTNLGRP_IPV4_ROUTE);
+                        (void) socket_broadcast_group_unref(nl, RTNLGRP_IPV6_ROUTE);
+
+                        break;
+                }
+
+                break;
+        default:
+                assert_not_reached("Wut? Unknown slot type?");
+        }
+
+        slot->type = _NETLINK_SLOT_INVALID;
+        slot->netlink = NULL;
+        LIST_REMOVE(slots, nl->slots, slot);
+
+        if (!slot->floating)
+                sd_netlink_unref(nl);
+        else if (unref)
+                sd_netlink_slot_unref(slot);
+}
+
+static sd_netlink_slot* netlink_slot_free(sd_netlink_slot *slot) {
+        assert(slot);
+
+        netlink_slot_disconnect(slot, false);
+
+        if (slot->destroy_callback)
+                slot->destroy_callback(slot->userdata);
+
+        free(slot->description);
+        return mfree(slot);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_netlink_slot, sd_netlink_slot, netlink_slot_free);
+
+sd_netlink *sd_netlink_slot_get_netlink(sd_netlink_slot *slot) {
+        assert_return(slot, NULL);
+
+        return slot->netlink;
+}
+
+void *sd_netlink_slot_get_userdata(sd_netlink_slot *slot) {
+        assert_return(slot, NULL);
+
+        return slot->userdata;
+}
+
+void *sd_netlink_slot_set_userdata(sd_netlink_slot *slot, void *userdata) {
+        void *ret;
+
+        assert_return(slot, NULL);
+
+        ret = slot->userdata;
+        slot->userdata = userdata;
+
+        return ret;
+}
+
+int sd_netlink_slot_get_destroy_callback(const sd_netlink_slot *slot, sd_netlink_destroy_t *callback) {
+        assert_return(slot, -EINVAL);
+
+        if (callback)
+                *callback = slot->destroy_callback;
+
+        return !!slot->destroy_callback;
+}
+
+int sd_netlink_slot_set_destroy_callback(sd_netlink_slot *slot, sd_netlink_destroy_t callback) {
+        assert_return(slot, -EINVAL);
+
+        slot->destroy_callback = callback;
+        return 0;
+}
+
+int sd_netlink_slot_get_floating(const sd_netlink_slot *slot) {
+        assert_return(slot, -EINVAL);
+
+        return slot->floating;
+}
+
+int sd_netlink_slot_set_floating(sd_netlink_slot *slot, int b) {
+        assert_return(slot, -EINVAL);
+
+        if (slot->floating == !!b)
+                return 0;
+
+        if (!slot->netlink) /* Already disconnected */
+                return -ESTALE;
+
+        slot->floating = b;
+
+        if (b) {
+                sd_netlink_slot_ref(slot);
+                sd_netlink_unref(slot->netlink);
+        } else {
+                sd_netlink_ref(slot->netlink);
+                sd_netlink_slot_unref(slot);
+        }
+
+        return 1;
+}
+
+int sd_netlink_slot_get_description(const sd_netlink_slot *slot, const char **description) {
+        assert_return(slot, -EINVAL);
+
+        if (description)
+                *description = slot->description;
+
+        return !!slot->description;
+}
+
+int sd_netlink_slot_set_description(sd_netlink_slot *slot, const char *description) {
+        assert_return(slot, -EINVAL);
+
+        return free_and_strdup(&slot->description, description);
+}
diff --git a/src/libsystemd/sd-netlink/netlink-slot.h b/src/libsystemd/sd-netlink/netlink-slot.h
new file mode 100644
index 0000000..79de817
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-slot.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-netlink.h"
+
+int netlink_slot_allocate(
+                sd_netlink *nl,
+                bool floating,
+                NetlinkSlotType type,
+                size_t extra,
+                void *userdata,
+                const char *description,
+                sd_netlink_slot **ret);
+void netlink_slot_disconnect(sd_netlink_slot *slot, bool unref);
diff --git a/src/libsystemd/sd-netlink/netlink-socket.c b/src/libsystemd/sd-netlink/netlink-socket.c
new file mode 100644
index 0000000..228e38d
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-socket.c
@@ -0,0 +1,444 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <netinet/in.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "io-util.h"
+#include "netlink-internal.h"
+#include "netlink-types.h"
+#include "netlink-util.h"
+#include "socket-util.h"
+#include "util.h"
+
+int socket_open(int family) {
+        int fd;
+
+        fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, family);
+        if (fd < 0)
+                return -errno;
+
+        return fd_move_above_stdio(fd);
+}
+
+static int broadcast_groups_get(sd_netlink *nl) {
+        _cleanup_free_ uint32_t *groups = NULL;
+        socklen_t len = 0, old_len;
+        unsigned i, j;
+        int r;
+
+        assert(nl);
+        assert(nl->fd >= 0);
+
+        r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, NULL, &len);
+        if (r < 0) {
+                if (errno == ENOPROTOOPT) {
+                        nl->broadcast_group_dont_leave = true;
+                        return 0;
+                } else
+                        return -errno;
+        }
+
+        if (len == 0)
+                return 0;
+
+        groups = new0(uint32_t, len);
+        if (!groups)
+                return -ENOMEM;
+
+        old_len = len;
+
+        r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, groups, &len);
+        if (r < 0)
+                return -errno;
+
+        if (old_len != len)
+                return -EIO;
+
+        r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL);
+        if (r < 0)
+                return r;
+
+        for (i = 0; i < len; i++) {
+                for (j = 0; j < sizeof(uint32_t) * 8; j++) {
+                        uint32_t offset;
+                        unsigned group;
+
+                        offset = 1U << j;
+
+                        if (!(groups[i] & offset))
+                                continue;
+
+                        group = i * sizeof(uint32_t) * 8 + j + 1;
+
+                        r = hashmap_put(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(1));
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        return 0;
+}
+
+int socket_bind(sd_netlink *nl) {
+        socklen_t addrlen;
+        int r;
+
+        r = setsockopt_int(nl->fd, SOL_NETLINK, NETLINK_PKTINFO, true);
+        if (r < 0)
+                return r;
+
+        addrlen = sizeof(nl->sockaddr);
+
+        r = bind(nl->fd, &nl->sockaddr.sa, addrlen);
+        /* ignore EINVAL to allow opening an already bound socket */
+        if (r < 0 && errno != EINVAL)
+                return -errno;
+
+        r = getsockname(nl->fd, &nl->sockaddr.sa, &addrlen);
+        if (r < 0)
+                return -errno;
+
+        r = broadcast_groups_get(nl);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static unsigned broadcast_group_get_ref(sd_netlink *nl, unsigned group) {
+        assert(nl);
+
+        return PTR_TO_UINT(hashmap_get(nl->broadcast_group_refs, UINT_TO_PTR(group)));
+}
+
+static int broadcast_group_set_ref(sd_netlink *nl, unsigned group, unsigned n_ref) {
+        int r;
+
+        assert(nl);
+
+        r = hashmap_replace(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(n_ref));
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int broadcast_group_join(sd_netlink *nl, unsigned group) {
+        int r;
+
+        assert(nl);
+        assert(nl->fd >= 0);
+        assert(group > 0);
+
+        r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+int socket_broadcast_group_ref(sd_netlink *nl, unsigned group) {
+        unsigned n_ref;
+        int r;
+
+        assert(nl);
+
+        n_ref = broadcast_group_get_ref(nl, group);
+
+        n_ref++;
+
+        r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL);
+        if (r < 0)
+                return r;
+
+        r = broadcast_group_set_ref(nl, group, n_ref);
+        if (r < 0)
+                return r;
+
+        if (n_ref > 1)
+                /* not yet in the group */
+                return 0;
+
+        r = broadcast_group_join(nl, group);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static int broadcast_group_leave(sd_netlink *nl, unsigned group) {
+        int r;
+
+        assert(nl);
+        assert(nl->fd >= 0);
+        assert(group > 0);
+
+        if (nl->broadcast_group_dont_leave)
+                return 0;
+
+        r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, &group, sizeof(group));
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
+int socket_broadcast_group_unref(sd_netlink *nl, unsigned group) {
+        unsigned n_ref;
+        int r;
+
+        assert(nl);
+
+        n_ref = broadcast_group_get_ref(nl, group);
+
+        assert(n_ref > 0);
+
+        n_ref--;
+
+        r = broadcast_group_set_ref(nl, group, n_ref);
+        if (r < 0)
+                return r;
+
+        if (n_ref > 0)
+                /* still refs left */
+                return 0;
+
+        r = broadcast_group_leave(nl, group);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+/* returns the number of bytes sent, or a negative error code */
+int socket_write_message(sd_netlink *nl, sd_netlink_message *m) {
+        union {
+                struct sockaddr sa;
+                struct sockaddr_nl nl;
+        } addr = {
+                .nl.nl_family = AF_NETLINK,
+        };
+        ssize_t k;
+
+        assert(nl);
+        assert(m);
+        assert(m->hdr);
+
+        k = sendto(nl->fd, m->hdr, m->hdr->nlmsg_len,
+                        0, &addr.sa, sizeof(addr));
+        if (k < 0)
+                return -errno;
+
+        return k;
+}
+
+static int socket_recv_message(int fd, struct iovec *iov, uint32_t *ret_mcast_group, bool peek) {
+        union sockaddr_union sender;
+        CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct nl_pktinfo))) control;
+        struct msghdr msg = {
+                .msg_iov = iov,
+                .msg_iovlen = 1,
+                .msg_name = &sender,
+                .msg_namelen = sizeof(sender),
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+        };
+        ssize_t n;
+
+        assert(fd >= 0);
+        assert(iov);
+
+        n = recvmsg_safe(fd, &msg, MSG_TRUNC | (peek ? MSG_PEEK : 0));
+        if (n == -ENOBUFS)
+                return log_debug_errno(n, "rtnl: kernel receive buffer overrun");
+        if (IN_SET(n, -EAGAIN, -EINTR))
+                return 0;
+        if (n < 0)
+                return (int) n;
+
+        if (sender.nl.nl_pid != 0) {
+                /* not from the kernel, ignore */
+                log_debug("rtnl: ignoring message from portid %"PRIu32, sender.nl.nl_pid);
+
+                if (peek) {
+                        /* drop the message */
+                        n = recvmsg_safe(fd, &msg, 0);
+                        if (n < 0)
+                                return (int) n;
+                }
+
+                return 0;
+        }
+
+        if (ret_mcast_group) {
+                struct nl_pktinfo *pi;
+
+                pi = CMSG_FIND_DATA(&msg, SOL_NETLINK, NETLINK_PKTINFO, struct nl_pktinfo);
+                if (pi)
+                        *ret_mcast_group = pi->group;
+                else
+                        *ret_mcast_group = 0;
+        }
+
+        return (int) n;
+}
+
+/* On success, the number of bytes received is returned and *ret points to the received message
+ * which has a valid header and the correct size.
+ * If nothing useful was received 0 is returned.
+ * On failure, a negative error code is returned.
+ */
+int socket_read_message(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *first = NULL;
+        struct iovec iov = {};
+        uint32_t group = 0;
+        bool multi_part = false, done = false;
+        struct nlmsghdr *new_msg;
+        size_t len;
+        int r;
+        unsigned i = 0;
+
+        assert(rtnl);
+        assert(rtnl->rbuffer);
+        assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr));
+
+        /* read nothing, just get the pending message size */
+        r = socket_recv_message(rtnl->fd, &iov, NULL, true);
+        if (r <= 0)
+                return r;
+        else
+                len = (size_t) r;
+
+        /* make room for the pending message */
+        if (!greedy_realloc((void **)&rtnl->rbuffer,
+                            &rtnl->rbuffer_allocated,
+                            len, sizeof(uint8_t)))
+                return -ENOMEM;
+
+        iov = IOVEC_MAKE(rtnl->rbuffer, rtnl->rbuffer_allocated);
+
+        /* read the pending message */
+        r = socket_recv_message(rtnl->fd, &iov, &group, false);
+        if (r <= 0)
+                return r;
+        else
+                len = (size_t) r;
+
+        if (len > rtnl->rbuffer_allocated)
+                /* message did not fit in read buffer */
+                return -EIO;
+
+        if (NLMSG_OK(rtnl->rbuffer, len) && rtnl->rbuffer->nlmsg_flags & NLM_F_MULTI) {
+                multi_part = true;
+
+                for (i = 0; i < rtnl->rqueue_partial_size; i++) {
+                        if (rtnl_message_get_serial(rtnl->rqueue_partial[i]) ==
+                            rtnl->rbuffer->nlmsg_seq) {
+                                first = rtnl->rqueue_partial[i];
+                                break;
+                        }
+                }
+        }
+
+        for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len) && !done; new_msg = NLMSG_NEXT(new_msg, len)) {
+                _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+                const NLType *nl_type;
+
+                if (!group && new_msg->nlmsg_pid != rtnl->sockaddr.nl.nl_pid)
+                        /* not broadcast and not for us */
+                        continue;
+
+                if (new_msg->nlmsg_type == NLMSG_NOOP)
+                        /* silently drop noop messages */
+                        continue;
+
+                if (new_msg->nlmsg_type == NLMSG_DONE) {
+                        /* finished reading multi-part message */
+                        done = true;
+
+                        /* if first is not defined, put NLMSG_DONE into the receive queue. */
+                        if (first)
+                                continue;
+                }
+
+                /* check that we support this message type */
+                r = type_system_root_get_type(rtnl, &nl_type, new_msg->nlmsg_type);
+                if (r < 0) {
+                        if (r == -EOPNOTSUPP)
+                                log_debug("sd-netlink: ignored message with unknown type: %i",
+                                          new_msg->nlmsg_type);
+
+                        continue;
+                }
+
+                /* check that the size matches the message type */
+                if (new_msg->nlmsg_len < NLMSG_LENGTH(type_get_size(nl_type))) {
+                        log_debug("sd-netlink: message is shorter than expected, dropping");
+                        continue;
+                }
+
+                r = message_new_empty(rtnl, &m);
+                if (r < 0)
+                        return r;
+
+                m->broadcast = !!group;
+
+                m->hdr = memdup(new_msg, new_msg->nlmsg_len);
+                if (!m->hdr)
+                        return -ENOMEM;
+
+                /* seal and parse the top-level message */
+                r = sd_netlink_message_rewind(m, rtnl);
+                if (r < 0)
+                        return r;
+
+                /* push the message onto the multi-part message stack */
+                if (first)
+                        m->next = first;
+                first = TAKE_PTR(m);
+        }
+
+        if (len > 0)
+                log_debug("sd-netlink: discarding %zu bytes of incoming message", len);
+
+        if (!first)
+                return 0;
+
+        if (!multi_part || done) {
+                /* we got a complete message, push it on the read queue */
+                r = rtnl_rqueue_make_room(rtnl);
+                if (r < 0)
+                        return r;
+
+                rtnl->rqueue[rtnl->rqueue_size++] = TAKE_PTR(first);
+
+                if (multi_part && (i < rtnl->rqueue_partial_size)) {
+                        /* remove the message form the partial read queue */
+                        memmove(rtnl->rqueue_partial + i,rtnl->rqueue_partial + i + 1,
+                                sizeof(sd_netlink_message*) * (rtnl->rqueue_partial_size - i - 1));
+                        rtnl->rqueue_partial_size--;
+                }
+
+                return 1;
+        } else {
+                /* we only got a partial multi-part message, push it on the
+                   partial read queue */
+                if (i < rtnl->rqueue_partial_size)
+                        rtnl->rqueue_partial[i] = TAKE_PTR(first);
+                else {
+                        r = rtnl_rqueue_partial_make_room(rtnl);
+                        if (r < 0)
+                                return r;
+
+                        rtnl->rqueue_partial[rtnl->rqueue_partial_size++] = TAKE_PTR(first);
+                }
+
+                return 0;
+        }
+}
diff --git a/src/libsystemd/sd-netlink/netlink-types.c b/src/libsystemd/sd-netlink/netlink-types.c
new file mode 100644
index 0000000..6fb6c14
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-types.c
@@ -0,0 +1,1488 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <netinet/in.h>
+#include <stdint.h>
+#include <sys/socket.h>
+#include <linux/can/vxcan.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/genetlink.h>
+#include <linux/ip.h>
+#include <linux/if.h>
+#include <linux/can/netlink.h>
+#include <linux/fib_rules.h>
+#include <linux/fou.h>
+#include <linux/if_addr.h>
+#include <linux/if_addrlabel.h>
+#include <linux/if_bridge.h>
+#include <linux/if_link.h>
+#include <linux/if_macsec.h>
+#include <linux/if_tunnel.h>
+#include <linux/l2tp.h>
+#include <linux/nexthop.h>
+#include <linux/nl80211.h>
+#include <linux/pkt_sched.h>
+#include <linux/veth.h>
+#include <linux/wireguard.h>
+
+#include "sd-netlink.h"
+
+#include "generic-netlink.h"
+#include "hashmap.h"
+#include "macro.h"
+#include "netlink-internal.h"
+#include "netlink-types.h"
+#include "string-table.h"
+#include "util.h"
+
+/* Maximum ARP IP target defined in kernel */
+#define BOND_MAX_ARP_TARGETS    16
+
+typedef enum {
+        BOND_ARP_TARGETS_0,
+        BOND_ARP_TARGETS_1,
+        BOND_ARP_TARGETS_2,
+        BOND_ARP_TARGETS_3,
+        BOND_ARP_TARGETS_4,
+        BOND_ARP_TARGETS_5,
+        BOND_ARP_TARGETS_6,
+        BOND_ARP_TARGETS_7,
+        BOND_ARP_TARGETS_8,
+        BOND_ARP_TARGETS_9,
+        BOND_ARP_TARGETS_10,
+        BOND_ARP_TARGETS_11,
+        BOND_ARP_TARGETS_12,
+        BOND_ARP_TARGETS_13,
+        BOND_ARP_TARGETS_14,
+        BOND_ARP_TARGETS_MAX = BOND_MAX_ARP_TARGETS,
+} BondArpTargets;
+
+struct NLType {
+        uint16_t type;
+        size_t size;
+        const NLTypeSystem *type_system;
+        const NLTypeSystemUnion *type_system_union;
+};
+
+struct NLTypeSystem {
+        uint16_t count;
+        const NLType *types;
+};
+
+static const NLTypeSystem rtnl_link_type_system;
+
+static const NLType empty_types[1] = {
+        /* fake array to avoid .types==NULL, which denotes invalid type-systems */
+};
+
+static const NLTypeSystem empty_type_system = {
+        .count = 0,
+        .types = empty_types,
+};
+
+static const NLType rtnl_link_info_data_veth_types[] = {
+        [VETH_INFO_PEER]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+};
+
+static const NLType rtnl_link_info_data_vxcan_types[] = {
+        [VXCAN_INFO_PEER]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+};
+
+static const NLType rtnl_link_info_data_ipvlan_types[] = {
+        [IFLA_IPVLAN_MODE]  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPVLAN_FLAGS]  = { .type = NETLINK_TYPE_U16 },
+};
+
+static const NLType rtnl_macvlan_macaddr_types[] = {
+        [IFLA_MACVLAN_MACADDR] = { .type = NETLINK_TYPE_ETHER_ADDR },
+};
+
+static const NLTypeSystem rtnl_macvlan_macaddr_type_system = {
+        .count = ELEMENTSOF(rtnl_macvlan_macaddr_types),
+        .types = rtnl_macvlan_macaddr_types,
+};
+
+static const NLType rtnl_link_info_data_macvlan_types[] = {
+        [IFLA_MACVLAN_MODE]  = { .type = NETLINK_TYPE_U32 },
+        [IFLA_MACVLAN_FLAGS] = { .type = NETLINK_TYPE_U16 },
+        [IFLA_MACVLAN_MACADDR_MODE] = { .type = NETLINK_TYPE_U32 },
+        [IFLA_MACVLAN_MACADDR_DATA] = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_macvlan_macaddr_type_system },
+};
+
+static const NLType rtnl_link_info_data_bridge_types[] = {
+        [IFLA_BR_FORWARD_DELAY]              = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_HELLO_TIME]                 = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_MAX_AGE]                    = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_AGEING_TIME]                = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_STP_STATE]                  = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_PRIORITY]                   = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_VLAN_FILTERING]             = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_VLAN_PROTOCOL]              = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_GROUP_FWD_MASK]             = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_ROOT_PORT]                  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_ROOT_PATH_COST]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_TOPOLOGY_CHANGE]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_TOPOLOGY_CHANGE_DETECTED]   = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_HELLO_TIMER]                = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_TCN_TIMER]                  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_TOPOLOGY_CHANGE_TIMER]      = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_GC_TIMER]                   = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_GROUP_ADDR]                 = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_FDB_FLUSH]                  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_MCAST_ROUTER]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_MCAST_SNOOPING]             = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_MCAST_QUERY_USE_IFADDR]     = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_MCAST_QUERIER]              = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_MCAST_HASH_ELASTICITY]      = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_MCAST_HASH_MAX]             = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_MCAST_LAST_MEMBER_CNT]      = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BR_MCAST_STARTUP_QUERY_CNT]    = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_MCAST_LAST_MEMBER_INTVL]    = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_MCAST_MEMBERSHIP_INTVL]     = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_MCAST_QUERIER_INTVL]        = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_MCAST_QUERY_INTVL]          = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_MCAST_QUERY_RESPONSE_INTVL] = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_MCAST_STARTUP_QUERY_INTVL]  = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BR_NF_CALL_IPTABLES]           = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_NF_CALL_IP6TABLES]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_NF_CALL_ARPTABLES]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BR_VLAN_DEFAULT_PVID]          = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BR_MCAST_IGMP_VERSION]         = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLType rtnl_link_info_data_vlan_types[] = {
+        [IFLA_VLAN_ID]          = { .type = NETLINK_TYPE_U16 },
+/*
+        [IFLA_VLAN_FLAGS]       = { .len = sizeof(struct ifla_vlan_flags) },
+        [IFLA_VLAN_EGRESS_QOS]  = { .type = NETLINK_TYPE_NESTED },
+        [IFLA_VLAN_INGRESS_QOS] = { .type = NETLINK_TYPE_NESTED },
+*/
+        [IFLA_VLAN_PROTOCOL]    = { .type = NETLINK_TYPE_U16 },
+};
+
+static const NLType rtnl_link_info_data_vxlan_types[] = {
+        [IFLA_VXLAN_ID]                = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VXLAN_GROUP]             = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_VXLAN_LINK]              = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VXLAN_LOCAL]             = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_VXLAN_TTL]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_TOS]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_LEARNING]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_AGEING]            = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VXLAN_LIMIT]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VXLAN_PORT_RANGE]        = { .type = NETLINK_TYPE_U32},
+        [IFLA_VXLAN_PROXY]             = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_RSC]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_L2MISS]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_L3MISS]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_PORT]              = { .type = NETLINK_TYPE_U16 },
+        [IFLA_VXLAN_GROUP6]            = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_VXLAN_LOCAL6]            = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_VXLAN_UDP_CSUM]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_UDP_ZERO_CSUM6_TX] = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_UDP_ZERO_CSUM6_RX] = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_REMCSUM_TX]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_REMCSUM_RX]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_GBP]               = { .type = NETLINK_TYPE_FLAG },
+        [IFLA_VXLAN_REMCSUM_NOPARTIAL] = { .type = NETLINK_TYPE_FLAG },
+        [IFLA_VXLAN_COLLECT_METADATA]  = { .type = NETLINK_TYPE_U8 },
+        [IFLA_VXLAN_LABEL]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VXLAN_GPE]               = { .type = NETLINK_TYPE_FLAG },
+        [IFLA_VXLAN_TTL_INHERIT]       = { .type = NETLINK_TYPE_FLAG },
+        [IFLA_VXLAN_DF]                = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLType rtnl_bond_arp_target_types[] = {
+        [BOND_ARP_TARGETS_0]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_1]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_2]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_3]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_4]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_5]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_6]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_7]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_8]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_9]        = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_10]       = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_11]       = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_12]       = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_13]       = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_14]       = { .type = NETLINK_TYPE_U32 },
+        [BOND_ARP_TARGETS_MAX]      = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_bond_arp_type_system = {
+        .count = ELEMENTSOF(rtnl_bond_arp_target_types),
+        .types = rtnl_bond_arp_target_types,
+};
+
+static const NLType rtnl_link_info_data_bond_types[] = {
+        [IFLA_BOND_MODE]                = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_ACTIVE_SLAVE]        = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_MIIMON]              = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_UPDELAY]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_DOWNDELAY]           = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_USE_CARRIER]         = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_ARP_INTERVAL]        = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_ARP_IP_TARGET]       = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_bond_arp_type_system },
+        [IFLA_BOND_ARP_VALIDATE]        = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_ARP_ALL_TARGETS]     = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_PRIMARY]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_PRIMARY_RESELECT]    = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_FAIL_OVER_MAC]       = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_XMIT_HASH_POLICY]    = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_RESEND_IGMP]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_NUM_PEER_NOTIF]      = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_ALL_SLAVES_ACTIVE]   = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_MIN_LINKS]           = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_LP_INTERVAL]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_PACKETS_PER_SLAVE]   = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BOND_AD_LACP_RATE]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_AD_SELECT]           = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BOND_AD_INFO]             = { .type = NETLINK_TYPE_NESTED },
+        [IFLA_BOND_AD_ACTOR_SYS_PRIO]   = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BOND_AD_USER_PORT_KEY]    = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BOND_AD_ACTOR_SYSTEM]     = { .type = NETLINK_TYPE_ETHER_ADDR },
+        [IFLA_BOND_TLB_DYNAMIC_LB]      = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLType rtnl_link_info_data_iptun_types[] = {
+        [IFLA_IPTUN_LINK]                = { .type = NETLINK_TYPE_U32 },
+        [IFLA_IPTUN_LOCAL]               = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_IPTUN_REMOTE]              = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_IPTUN_TTL]                 = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_TOS]                 = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_PMTUDISC]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_FLAGS]               = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPTUN_PROTO]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_6RD_PREFIX]          = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_IPTUN_6RD_RELAY_PREFIX]    = { .type = NETLINK_TYPE_U32 },
+        [IFLA_IPTUN_6RD_PREFIXLEN]       = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPTUN_ENCAP_TYPE]          = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPTUN_ENCAP_FLAGS]         = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPTUN_ENCAP_SPORT]         = { .type = NETLINK_TYPE_U16 },
+        [IFLA_IPTUN_ENCAP_DPORT]         = { .type = NETLINK_TYPE_U16 },
+};
+
+static  const NLType rtnl_link_info_data_ipgre_types[] = {
+        [IFLA_GRE_LINK]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GRE_IFLAGS]       = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_OFLAGS]       = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_IKEY]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GRE_OKEY]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GRE_LOCAL]        = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_GRE_REMOTE]       = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_GRE_TTL]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GRE_TOS]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GRE_PMTUDISC]     = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GRE_FLOWINFO]     = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GRE_FLAGS]        = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GRE_ENCAP_TYPE]   = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_ENCAP_FLAGS]  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_ENCAP_SPORT]  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_ENCAP_DPORT]  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GRE_ERSPAN_INDEX] = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_link_info_data_ipvti_types[] = {
+        [IFLA_VTI_LINK]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VTI_IKEY]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VTI_OKEY]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VTI_LOCAL]        = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_VTI_REMOTE]       = { .type = NETLINK_TYPE_IN_ADDR },
+};
+
+static const NLType rtnl_link_info_data_ip6tnl_types[] = {
+        [IFLA_IPTUN_LINK]                = { .type = NETLINK_TYPE_U32 },
+        [IFLA_IPTUN_LOCAL]               = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_IPTUN_REMOTE]              = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_IPTUN_TTL]                 = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_FLAGS]               = { .type = NETLINK_TYPE_U32 },
+        [IFLA_IPTUN_PROTO]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_ENCAP_LIMIT]         = { .type = NETLINK_TYPE_U8 },
+        [IFLA_IPTUN_FLOWINFO]            = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_link_info_data_vrf_types[] = {
+        [IFLA_VRF_TABLE]                 = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_link_info_data_geneve_types[] = {
+        [IFLA_GENEVE_ID]                = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GENEVE_TTL]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GENEVE_TOS]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GENEVE_PORT]              = { .type = NETLINK_TYPE_U16 },
+        [IFLA_GENEVE_REMOTE]            = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_GENEVE_REMOTE6]           = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_GENEVE_UDP_CSUM]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GENEVE_UDP_ZERO_CSUM6_TX] = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GENEVE_UDP_ZERO_CSUM6_RX] = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GENEVE_LABEL]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_GENEVE_TTL_INHERIT]       = { .type = NETLINK_TYPE_U8 },
+        [IFLA_GENEVE_DF]                = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLType rtnl_link_info_data_can_types[] = {
+        [IFLA_CAN_BITTIMING]            = { .size = sizeof(struct can_bittiming) },
+        [IFLA_CAN_RESTART_MS]           = { .type = NETLINK_TYPE_U32 },
+        [IFLA_CAN_CTRLMODE]             = { .size = sizeof(struct can_ctrlmode) },
+        [IFLA_CAN_TERMINATION]          = { .type = NETLINK_TYPE_U16 },
+};
+
+static const NLType rtnl_link_info_data_macsec_types[] = {
+        [IFLA_MACSEC_SCI]            = { .type = NETLINK_TYPE_U64 },
+        [IFLA_MACSEC_PORT]           = { .type = NETLINK_TYPE_U16 },
+        [IFLA_MACSEC_ICV_LEN]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_CIPHER_SUITE]   = { .type = NETLINK_TYPE_U64 },
+        [IFLA_MACSEC_WINDOW]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_MACSEC_ENCODING_SA]    = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_ENCRYPT]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_PROTECT]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_INC_SCI]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_ES]             = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_SCB]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_REPLAY_PROTECT] = { .type = NETLINK_TYPE_U8 },
+        [IFLA_MACSEC_VALIDATION]     = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLType rtnl_link_info_data_xfrm_types[] = {
+        [IFLA_XFRM_LINK]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_XFRM_IF_ID]        = { .type = NETLINK_TYPE_U32 }
+};
+
+static const NLType rtnl_link_info_data_bareudp_types[] = {
+        [IFLA_BAREUDP_PORT]            = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BAREUDP_ETHERTYPE]       = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BAREUDP_SRCPORT_MIN]     = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BAREUDP_MULTIPROTO_MODE] = { .type = NETLINK_TYPE_FLAG },
+};
+/* these strings must match the .kind entries in the kernel */
+static const char* const nl_union_link_info_data_table[] = {
+        [NL_UNION_LINK_INFO_DATA_BOND] = "bond",
+        [NL_UNION_LINK_INFO_DATA_BRIDGE] = "bridge",
+        [NL_UNION_LINK_INFO_DATA_VLAN] = "vlan",
+        [NL_UNION_LINK_INFO_DATA_VETH] = "veth",
+        [NL_UNION_LINK_INFO_DATA_DUMMY] = "dummy",
+        [NL_UNION_LINK_INFO_DATA_MACVLAN] = "macvlan",
+        [NL_UNION_LINK_INFO_DATA_MACVTAP] = "macvtap",
+        [NL_UNION_LINK_INFO_DATA_IPVLAN] = "ipvlan",
+        [NL_UNION_LINK_INFO_DATA_IPVTAP] = "ipvtap",
+        [NL_UNION_LINK_INFO_DATA_VXLAN] = "vxlan",
+        [NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL] = "ipip",
+        [NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL] = "gre",
+        [NL_UNION_LINK_INFO_DATA_ERSPAN] = "erspan",
+        [NL_UNION_LINK_INFO_DATA_IPGRETAP_TUNNEL] = "gretap",
+        [NL_UNION_LINK_INFO_DATA_IP6GRE_TUNNEL] = "ip6gre",
+        [NL_UNION_LINK_INFO_DATA_IP6GRETAP_TUNNEL] = "ip6gretap",
+        [NL_UNION_LINK_INFO_DATA_SIT_TUNNEL] = "sit",
+        [NL_UNION_LINK_INFO_DATA_VTI_TUNNEL] = "vti",
+        [NL_UNION_LINK_INFO_DATA_VTI6_TUNNEL] = "vti6",
+        [NL_UNION_LINK_INFO_DATA_IP6TNL_TUNNEL] = "ip6tnl",
+        [NL_UNION_LINK_INFO_DATA_VRF] = "vrf",
+        [NL_UNION_LINK_INFO_DATA_VCAN] = "vcan",
+        [NL_UNION_LINK_INFO_DATA_GENEVE] = "geneve",
+        [NL_UNION_LINK_INFO_DATA_VXCAN] = "vxcan",
+        [NL_UNION_LINK_INFO_DATA_WIREGUARD] = "wireguard",
+        [NL_UNION_LINK_INFO_DATA_NETDEVSIM] = "netdevsim",
+        [NL_UNION_LINK_INFO_DATA_CAN] = "can",
+        [NL_UNION_LINK_INFO_DATA_MACSEC] = "macsec",
+        [NL_UNION_LINK_INFO_DATA_NLMON] = "nlmon",
+        [NL_UNION_LINK_INFO_DATA_XFRM] = "xfrm",
+        [NL_UNION_LINK_INFO_DATA_IFB] = "ifb",
+        [NL_UNION_LINK_INFO_DATA_BAREUDP] = "bareudp",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(nl_union_link_info_data, NLUnionLinkInfoData);
+
+static const NLTypeSystem rtnl_link_info_data_type_systems[] = {
+        [NL_UNION_LINK_INFO_DATA_BOND] =             { .count = ELEMENTSOF(rtnl_link_info_data_bond_types),
+                                                       .types = rtnl_link_info_data_bond_types },
+        [NL_UNION_LINK_INFO_DATA_BRIDGE] =           { .count = ELEMENTSOF(rtnl_link_info_data_bridge_types),
+                                                       .types = rtnl_link_info_data_bridge_types },
+        [NL_UNION_LINK_INFO_DATA_VLAN] =             { .count = ELEMENTSOF(rtnl_link_info_data_vlan_types),
+                                                       .types = rtnl_link_info_data_vlan_types },
+        [NL_UNION_LINK_INFO_DATA_VETH] =             { .count = ELEMENTSOF(rtnl_link_info_data_veth_types),
+                                                       .types = rtnl_link_info_data_veth_types },
+        [NL_UNION_LINK_INFO_DATA_MACVLAN] =          { .count = ELEMENTSOF(rtnl_link_info_data_macvlan_types),
+                                                       .types = rtnl_link_info_data_macvlan_types },
+        [NL_UNION_LINK_INFO_DATA_MACVTAP] =          { .count = ELEMENTSOF(rtnl_link_info_data_macvlan_types),
+                                                       .types = rtnl_link_info_data_macvlan_types },
+        [NL_UNION_LINK_INFO_DATA_IPVLAN] =           { .count = ELEMENTSOF(rtnl_link_info_data_ipvlan_types),
+                                                       .types = rtnl_link_info_data_ipvlan_types },
+        [NL_UNION_LINK_INFO_DATA_IPVTAP] =           { .count = ELEMENTSOF(rtnl_link_info_data_ipvlan_types),
+                                                       .types = rtnl_link_info_data_ipvlan_types },
+        [NL_UNION_LINK_INFO_DATA_VXLAN] =            { .count = ELEMENTSOF(rtnl_link_info_data_vxlan_types),
+                                                       .types = rtnl_link_info_data_vxlan_types },
+        [NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL] =      { .count = ELEMENTSOF(rtnl_link_info_data_iptun_types),
+                                                       .types = rtnl_link_info_data_iptun_types },
+        [NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL] =     { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
+                                                       .types = rtnl_link_info_data_ipgre_types },
+        [NL_UNION_LINK_INFO_DATA_ERSPAN] =           { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
+                                                       .types = rtnl_link_info_data_ipgre_types },
+        [NL_UNION_LINK_INFO_DATA_IPGRETAP_TUNNEL] =  { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
+                                                       .types = rtnl_link_info_data_ipgre_types },
+        [NL_UNION_LINK_INFO_DATA_IP6GRE_TUNNEL] =    { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
+                                                       .types = rtnl_link_info_data_ipgre_types },
+        [NL_UNION_LINK_INFO_DATA_IP6GRETAP_TUNNEL] = { .count = ELEMENTSOF(rtnl_link_info_data_ipgre_types),
+                                                       .types = rtnl_link_info_data_ipgre_types },
+        [NL_UNION_LINK_INFO_DATA_SIT_TUNNEL] =       { .count = ELEMENTSOF(rtnl_link_info_data_iptun_types),
+                                                       .types = rtnl_link_info_data_iptun_types },
+        [NL_UNION_LINK_INFO_DATA_VTI_TUNNEL] =       { .count = ELEMENTSOF(rtnl_link_info_data_ipvti_types),
+                                                       .types = rtnl_link_info_data_ipvti_types },
+        [NL_UNION_LINK_INFO_DATA_VTI6_TUNNEL] =      { .count = ELEMENTSOF(rtnl_link_info_data_ipvti_types),
+                                                       .types = rtnl_link_info_data_ipvti_types },
+        [NL_UNION_LINK_INFO_DATA_IP6TNL_TUNNEL] =    { .count = ELEMENTSOF(rtnl_link_info_data_ip6tnl_types),
+                                                       .types = rtnl_link_info_data_ip6tnl_types },
+        [NL_UNION_LINK_INFO_DATA_VRF] =              { .count = ELEMENTSOF(rtnl_link_info_data_vrf_types),
+                                                       .types = rtnl_link_info_data_vrf_types },
+        [NL_UNION_LINK_INFO_DATA_GENEVE] =           { .count = ELEMENTSOF(rtnl_link_info_data_geneve_types),
+                                                       .types = rtnl_link_info_data_geneve_types },
+        [NL_UNION_LINK_INFO_DATA_VXCAN] =            { .count = ELEMENTSOF(rtnl_link_info_data_vxcan_types),
+                                                       .types = rtnl_link_info_data_vxcan_types },
+        [NL_UNION_LINK_INFO_DATA_CAN] =              { .count = ELEMENTSOF(rtnl_link_info_data_can_types),
+                                                       .types = rtnl_link_info_data_can_types },
+        [NL_UNION_LINK_INFO_DATA_MACSEC] =           { .count = ELEMENTSOF(rtnl_link_info_data_macsec_types),
+                                                       .types = rtnl_link_info_data_macsec_types },
+        [NL_UNION_LINK_INFO_DATA_XFRM] =             { .count = ELEMENTSOF(rtnl_link_info_data_xfrm_types),
+                                                       .types = rtnl_link_info_data_xfrm_types },
+        [NL_UNION_LINK_INFO_DATA_BAREUDP] =          { .count = ELEMENTSOF(rtnl_link_info_data_bareudp_types),
+                                                       .types = rtnl_link_info_data_bareudp_types },
+};
+
+static const NLTypeSystemUnion rtnl_link_info_data_type_system_union = {
+        .num = _NL_UNION_LINK_INFO_DATA_MAX,
+        .lookup = nl_union_link_info_data_from_string,
+        .type_systems = rtnl_link_info_data_type_systems,
+        .match_type = NL_MATCH_SIBLING,
+        .match = IFLA_INFO_KIND,
+};
+
+static const NLType rtnl_link_info_types[] = {
+        [IFLA_INFO_KIND]        = { .type = NETLINK_TYPE_STRING },
+        [IFLA_INFO_DATA]        = { .type = NETLINK_TYPE_UNION, .type_system_union = &rtnl_link_info_data_type_system_union },
+/*
+        [IFLA_INFO_XSTATS],
+        [IFLA_INFO_SLAVE_KIND]  = { .type = NETLINK_TYPE_STRING },
+        [IFLA_INFO_SLAVE_DATA]  = { .type = NETLINK_TYPE_NESTED },
+*/
+};
+
+static const NLTypeSystem rtnl_link_info_type_system = {
+        .count = ELEMENTSOF(rtnl_link_info_types),
+        .types = rtnl_link_info_types,
+};
+
+static const struct NLType rtnl_prot_info_bridge_port_types[] = {
+        [IFLA_BRPORT_STATE]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_COST]                = { .type = NETLINK_TYPE_U32 },
+        [IFLA_BRPORT_PRIORITY]            = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BRPORT_MODE]                = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_GUARD]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_PROTECT]             = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_FAST_LEAVE]          = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_LEARNING]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_UNICAST_FLOOD]       = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_PROXYARP]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_LEARNING_SYNC]       = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_PROXYARP_WIFI]       = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_ROOT_ID]             = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_BRIDGE_ID]           = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_DESIGNATED_PORT]     = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BRPORT_DESIGNATED_COST]     = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BRPORT_ID]                  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BRPORT_NO]                  = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BRPORT_TOPOLOGY_CHANGE_ACK] = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_CONFIG_PENDING]      = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_MESSAGE_AGE_TIMER]   = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BRPORT_FORWARD_DELAY_TIMER] = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BRPORT_HOLD_TIMER]          = { .type = NETLINK_TYPE_U64 },
+        [IFLA_BRPORT_FLUSH]               = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_MULTICAST_ROUTER]    = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_PAD]                 = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_MCAST_FLOOD]         = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_MCAST_TO_UCAST]      = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_VLAN_TUNNEL]         = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_BCAST_FLOOD]         = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_GROUP_FWD_MASK]      = { .type = NETLINK_TYPE_U16 },
+        [IFLA_BRPORT_NEIGH_SUPPRESS]      = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_ISOLATED]            = { .type = NETLINK_TYPE_U8 },
+        [IFLA_BRPORT_BACKUP_PORT]         = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_prot_info_type_systems[] = {
+        [AF_BRIDGE] =   { .count = ELEMENTSOF(rtnl_prot_info_bridge_port_types),
+                          .types = rtnl_prot_info_bridge_port_types },
+};
+
+static const NLTypeSystemUnion rtnl_prot_info_type_system_union = {
+        .num = AF_MAX,
+        .type_systems = rtnl_prot_info_type_systems,
+        .match_type = NL_MATCH_PROTOCOL,
+};
+
+static const struct NLType rtnl_af_spec_inet6_types[] = {
+        [IFLA_INET6_FLAGS]              = { .type = NETLINK_TYPE_U32 },
+/*
+        IFLA_INET6_CONF,
+        IFLA_INET6_STATS,
+        IFLA_INET6_MCAST,
+        IFLA_INET6_CACHEINFO,
+        IFLA_INET6_ICMP6STATS,
+*/
+        [IFLA_INET6_TOKEN]              = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFLA_INET6_ADDR_GEN_MODE]      = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLTypeSystem rtnl_af_spec_inet6_type_system = {
+        .count = ELEMENTSOF(rtnl_af_spec_inet6_types),
+        .types = rtnl_af_spec_inet6_types,
+};
+
+static const NLType rtnl_af_spec_types[] = {
+        [AF_INET6] =    { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_af_spec_inet6_type_system },
+};
+
+static const NLTypeSystem rtnl_af_spec_type_system = {
+        .count = ELEMENTSOF(rtnl_af_spec_types),
+        .types = rtnl_af_spec_types,
+};
+
+static const NLType rtnl_prop_list_types[] = {
+        [IFLA_ALT_IFNAME]       = { .type = NETLINK_TYPE_STRING, .size = ALTIFNAMSIZ - 1 },
+};
+
+static const NLTypeSystem rtnl_prop_list_type_system = {
+        .count = ELEMENTSOF(rtnl_prop_list_types),
+        .types = rtnl_prop_list_types,
+};
+
+static const NLType rtnl_vf_vlan_list_types[] = {
+        [IFLA_VF_VLAN_INFO]  = { .size = sizeof(struct ifla_vf_vlan_info) },
+};
+
+static const NLTypeSystem rtnl_vf_vlan_type_system = {
+        .count = ELEMENTSOF(rtnl_vf_vlan_list_types),
+        .types = rtnl_vf_vlan_list_types,
+};
+
+static const NLType rtnl_vf_vlan_info_types[] = {
+        [IFLA_VF_MAC]           = { .size = sizeof(struct ifla_vf_mac) },
+        [IFLA_VF_VLAN]          = { .size = sizeof(struct ifla_vf_vlan) },
+        [IFLA_VF_VLAN_LIST]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_vf_vlan_type_system},
+        [IFLA_VF_TX_RATE]       = { .size = sizeof(struct ifla_vf_tx_rate) },
+        [IFLA_VF_SPOOFCHK]      = { .size = sizeof(struct ifla_vf_spoofchk) },
+        [IFLA_VF_RATE]          = { .size = sizeof(struct ifla_vf_rate) },
+        [IFLA_VF_LINK_STATE]    = { .size = sizeof(struct ifla_vf_link_state) },
+        [IFLA_VF_RSS_QUERY_EN]  = { .size = sizeof(struct ifla_vf_rss_query_en) },
+        [IFLA_VF_TRUST]         = { .size = sizeof(struct ifla_vf_trust) },
+        [IFLA_VF_IB_NODE_GUID]  = { .size = sizeof(struct ifla_vf_guid) },
+        [IFLA_VF_IB_PORT_GUID]  = { .size = sizeof(struct ifla_vf_guid) },
+};
+
+static const NLTypeSystem rtnl_vf_vlan_info_type_system = {
+        .count = ELEMENTSOF(rtnl_vf_vlan_info_types),
+        .types = rtnl_vf_vlan_info_types,
+};
+
+static const NLType rtnl_link_io_srv_types[] = {
+        [IFLA_VF_INFO] = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_vf_vlan_info_type_system },
+};
+
+static const NLTypeSystem rtnl_io_srv_type_system = {
+        .count = ELEMENTSOF(rtnl_link_io_srv_types),
+        .types = rtnl_link_io_srv_types,
+};
+
+static const NLType rtnl_link_types[] = {
+        [IFLA_ADDRESS]          = { .type = NETLINK_TYPE_ETHER_ADDR },
+        [IFLA_BROADCAST]        = { .type = NETLINK_TYPE_ETHER_ADDR },
+        [IFLA_IFNAME]           = { .type = NETLINK_TYPE_STRING, .size = IFNAMSIZ - 1 },
+        [IFLA_MTU]              = { .type = NETLINK_TYPE_U32 },
+        [IFLA_LINK]             = { .type = NETLINK_TYPE_U32 },
+        [IFLA_QDISC]            = { .type = NETLINK_TYPE_STRING },
+        [IFLA_STATS]            = { .size = sizeof(struct rtnl_link_stats) },
+/*
+        [IFLA_COST],
+        [IFLA_PRIORITY],
+*/
+        [IFLA_MASTER]           = { .type = NETLINK_TYPE_U32 },
+/*
+        [IFLA_WIRELESS],
+*/
+        [IFLA_PROTINFO]         = { .type = NETLINK_TYPE_UNION, .type_system_union = &rtnl_prot_info_type_system_union },
+        [IFLA_TXQLEN]           = { .type = NETLINK_TYPE_U32 },
+/*
+        [IFLA_MAP]              = { .len = sizeof(struct rtnl_link_ifmap) },
+*/
+        [IFLA_WEIGHT]           = { .type = NETLINK_TYPE_U32 },
+        [IFLA_OPERSTATE]        = { .type = NETLINK_TYPE_U8 },
+        [IFLA_LINKMODE]         = { .type = NETLINK_TYPE_U8 },
+        [IFLA_LINKINFO]         = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_info_type_system },
+        [IFLA_NET_NS_PID]       = { .type = NETLINK_TYPE_U32 },
+        [IFLA_IFALIAS]          = { .type = NETLINK_TYPE_STRING, .size = IFALIASZ - 1 },
+        [IFLA_NUM_VF]           = { .type = NETLINK_TYPE_U32 },
+        [IFLA_VFINFO_LIST]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_io_srv_type_system },
+        [IFLA_STATS64]          = { .size = sizeof(struct rtnl_link_stats64) },
+/*
+        [IFLA_VF_PORTS]         = { .type = NETLINK_TYPE_NESTED },
+        [IFLA_PORT_SELF]        = { .type = NETLINK_TYPE_NESTED },
+*/
+        [IFLA_AF_SPEC]          = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_af_spec_type_system },
+/*
+        [IFLA_VF_PORTS],
+        [IFLA_PORT_SELF],
+        [IFLA_AF_SPEC],
+*/
+        [IFLA_GROUP]            = { .type = NETLINK_TYPE_U32 },
+        [IFLA_NET_NS_FD]        = { .type = NETLINK_TYPE_U32 },
+        [IFLA_EXT_MASK]         = { .type = NETLINK_TYPE_U32 },
+        [IFLA_PROMISCUITY]      = { .type = NETLINK_TYPE_U32 },
+        [IFLA_NUM_TX_QUEUES]    = { .type = NETLINK_TYPE_U32 },
+        [IFLA_NUM_RX_QUEUES]    = { .type = NETLINK_TYPE_U32 },
+        [IFLA_CARRIER]          = { .type = NETLINK_TYPE_U8 },
+/*
+        [IFLA_PHYS_PORT_ID]     = { .type = NETLINK_TYPE_BINARY, .len = MAX_PHYS_PORT_ID_LEN },
+*/
+        [IFLA_MIN_MTU]          = { .type = NETLINK_TYPE_U32 },
+        [IFLA_MAX_MTU]          = { .type = NETLINK_TYPE_U32 },
+        [IFLA_PROP_LIST]        = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_prop_list_type_system },
+        [IFLA_ALT_IFNAME]       = { .type = NETLINK_TYPE_STRING, .size = ALTIFNAMSIZ - 1 },
+};
+
+static const NLTypeSystem rtnl_link_type_system = {
+        .count = ELEMENTSOF(rtnl_link_types),
+        .types = rtnl_link_types,
+};
+
+/* IFA_FLAGS was defined in kernel 3.14, but we still support older
+ * kernels where IFA_MAX is lower. */
+static const NLType rtnl_address_types[] = {
+        [IFA_ADDRESS]           = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFA_LOCAL]             = { .type = NETLINK_TYPE_IN_ADDR },
+        [IFA_LABEL]             = { .type = NETLINK_TYPE_STRING, .size = IFNAMSIZ - 1 },
+        [IFA_BROADCAST]         = { .type = NETLINK_TYPE_IN_ADDR }, /* 6? */
+        [IFA_CACHEINFO]         = { .type = NETLINK_TYPE_CACHE_INFO, .size = sizeof(struct ifa_cacheinfo) },
+/*
+        [IFA_ANYCAST],
+        [IFA_MULTICAST],
+*/
+        [IFA_FLAGS]             = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_address_type_system = {
+        .count = ELEMENTSOF(rtnl_address_types),
+        .types = rtnl_address_types,
+};
+
+/* RTM_METRICS --- array of struct rtattr with types of RTAX_* */
+
+static const NLType rtnl_route_metrics_types[] = {
+        [RTAX_MTU]                = { .type = NETLINK_TYPE_U32 },
+        [RTAX_WINDOW]             = { .type = NETLINK_TYPE_U32 },
+        [RTAX_RTT]                = { .type = NETLINK_TYPE_U32 },
+        [RTAX_RTTVAR]             = { .type = NETLINK_TYPE_U32 },
+        [RTAX_SSTHRESH]           = { .type = NETLINK_TYPE_U32 },
+        [RTAX_CWND]               = { .type = NETLINK_TYPE_U32 },
+        [RTAX_ADVMSS]             = { .type = NETLINK_TYPE_U32 },
+        [RTAX_REORDERING]         = { .type = NETLINK_TYPE_U32 },
+        [RTAX_HOPLIMIT]           = { .type = NETLINK_TYPE_U32 },
+        [RTAX_INITCWND]           = { .type = NETLINK_TYPE_U32 },
+        [RTAX_FEATURES]           = { .type = NETLINK_TYPE_U32 },
+        [RTAX_RTO_MIN]            = { .type = NETLINK_TYPE_U32 },
+        [RTAX_INITRWND]           = { .type = NETLINK_TYPE_U32 },
+        [RTAX_QUICKACK]           = { .type = NETLINK_TYPE_U32 },
+        [RTAX_CC_ALGO]            = { .type = NETLINK_TYPE_U32 },
+        [RTAX_FASTOPEN_NO_COOKIE] = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_route_metrics_type_system = {
+        .count = ELEMENTSOF(rtnl_route_metrics_types),
+        .types = rtnl_route_metrics_types,
+};
+
+static const NLType rtnl_route_types[] = {
+        [RTA_DST]               = { .type = NETLINK_TYPE_IN_ADDR }, /* 6? */
+        [RTA_SRC]               = { .type = NETLINK_TYPE_IN_ADDR }, /* 6? */
+        [RTA_IIF]               = { .type = NETLINK_TYPE_U32 },
+        [RTA_OIF]               = { .type = NETLINK_TYPE_U32 },
+        [RTA_GATEWAY]           = { .type = NETLINK_TYPE_IN_ADDR },
+        [RTA_PRIORITY]          = { .type = NETLINK_TYPE_U32 },
+        [RTA_PREFSRC]           = { .type = NETLINK_TYPE_IN_ADDR }, /* 6? */
+        [RTA_METRICS]           = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_route_metrics_type_system},
+        [RTA_MULTIPATH]         = { .size = sizeof(struct rtnexthop) },
+        [RTA_FLOW]              = { .type = NETLINK_TYPE_U32 }, /* 6? */
+        [RTA_CACHEINFO]         = { .size = sizeof(struct rta_cacheinfo) },
+        [RTA_TABLE]             = { .type = NETLINK_TYPE_U32 },
+        [RTA_MARK]              = { .type = NETLINK_TYPE_U32 },
+        [RTA_MFC_STATS]         = { .type = NETLINK_TYPE_U64 },
+        [RTA_VIA]               = { /* See struct rtvia */ },
+        [RTA_NEWDST]            = { .type = NETLINK_TYPE_U32 },
+        [RTA_PREF]              = { .type = NETLINK_TYPE_U8 },
+        [RTA_EXPIRES]           = { .type = NETLINK_TYPE_U32 },
+        [RTA_ENCAP_TYPE]        = { .type = NETLINK_TYPE_U16 },
+        [RTA_ENCAP]             = { .type = NETLINK_TYPE_NESTED }, /* Multiple type systems i.e. LWTUNNEL_ENCAP_MPLS/LWTUNNEL_ENCAP_IP/LWTUNNEL_ENCAP_ILA etc... */
+        [RTA_UID]               = { .type = NETLINK_TYPE_U32 },
+        [RTA_TTL_PROPAGATE]     = { .type = NETLINK_TYPE_U8 },
+        [RTA_IP_PROTO]          = { .type = NETLINK_TYPE_U8 },
+        [RTA_SPORT]             = { .type = NETLINK_TYPE_U16 },
+        [RTA_DPORT]             = { .type = NETLINK_TYPE_U16 },
+};
+
+static const NLTypeSystem rtnl_route_type_system = {
+        .count = ELEMENTSOF(rtnl_route_types),
+        .types = rtnl_route_types,
+};
+
+static const NLType rtnl_neigh_types[] = {
+        [NDA_DST]               = { .type = NETLINK_TYPE_IN_ADDR },
+        [NDA_LLADDR]            = { /* struct ether_addr, struct in_addr, or struct in6_addr */ },
+        [NDA_CACHEINFO]         = { .type = NETLINK_TYPE_CACHE_INFO, .size = sizeof(struct nda_cacheinfo) },
+        [NDA_PROBES]            = { .type = NETLINK_TYPE_U32 },
+        [NDA_VLAN]              = { .type = NETLINK_TYPE_U16 },
+        [NDA_PORT]              = { .type = NETLINK_TYPE_U16 },
+        [NDA_VNI]               = { .type = NETLINK_TYPE_U32 },
+        [NDA_IFINDEX]           = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_neigh_type_system = {
+        .count = ELEMENTSOF(rtnl_neigh_types),
+        .types = rtnl_neigh_types,
+};
+
+static const NLType rtnl_addrlabel_types[] = {
+        [IFAL_ADDRESS]         = { .type = NETLINK_TYPE_IN_ADDR, .size = sizeof(struct in6_addr) },
+        [IFAL_LABEL]           = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_addrlabel_type_system = {
+        .count = ELEMENTSOF(rtnl_addrlabel_types),
+        .types = rtnl_addrlabel_types,
+};
+
+static const NLType rtnl_routing_policy_rule_types[] = {
+        [FRA_DST]                 = { .type = NETLINK_TYPE_IN_ADDR },
+        [FRA_SRC]                 = { .type = NETLINK_TYPE_IN_ADDR },
+        [FRA_IIFNAME]             = { .type = NETLINK_TYPE_STRING },
+        [FRA_GOTO]                = { .type = NETLINK_TYPE_U32 },
+        [FRA_PRIORITY]            = { .type = NETLINK_TYPE_U32 },
+        [FRA_FWMARK]              = { .type = NETLINK_TYPE_U32 },
+        [FRA_FLOW]                = { .type = NETLINK_TYPE_U32 },
+        [FRA_TUN_ID]              = { .type = NETLINK_TYPE_U64 },
+        [FRA_SUPPRESS_IFGROUP]    = { .type = NETLINK_TYPE_U32 },
+        [FRA_SUPPRESS_PREFIXLEN]  = { .type = NETLINK_TYPE_U32 },
+        [FRA_TABLE]               = { .type = NETLINK_TYPE_U32 },
+        [FRA_FWMASK]              = { .type = NETLINK_TYPE_U32 },
+        [FRA_OIFNAME]             = { .type = NETLINK_TYPE_STRING },
+        [FRA_PAD]                 = { .type = NETLINK_TYPE_U32 },
+        [FRA_L3MDEV]              = { .type = NETLINK_TYPE_U8 },
+        [FRA_UID_RANGE]           = { .size = sizeof(struct fib_rule_uid_range) },
+        [FRA_PROTOCOL]            = { .type = NETLINK_TYPE_U8 },
+        [FRA_IP_PROTO]            = { .type = NETLINK_TYPE_U8 },
+        [FRA_SPORT_RANGE]         = { .size = sizeof(struct fib_rule_port_range) },
+        [FRA_DPORT_RANGE]         = { .size = sizeof(struct fib_rule_port_range) },
+};
+
+static const NLTypeSystem rtnl_routing_policy_rule_type_system = {
+        .count = ELEMENTSOF(rtnl_routing_policy_rule_types),
+        .types = rtnl_routing_policy_rule_types,
+};
+
+static const NLType rtnl_nexthop_types[] = {
+        [NHA_ID]                  = { .type = NETLINK_TYPE_U32 },
+        [NHA_OIF]                 = { .type = NETLINK_TYPE_U32 },
+        [NHA_GATEWAY]             = { .type = NETLINK_TYPE_IN_ADDR },
+};
+
+static const NLTypeSystem rtnl_nexthop_type_system = {
+       .count = ELEMENTSOF(rtnl_nexthop_types),
+       .types = rtnl_nexthop_types,
+};
+
+static const NLType rtnl_tca_option_data_cake_types[] = {
+        [TCA_CAKE_BASE_RATE64] = { .type = NETLINK_TYPE_U64 },
+        [TCA_CAKE_OVERHEAD]    = { .type = NETLINK_TYPE_S32 },
+        [TCA_CAKE_MPU]         = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_codel_types[] = {
+        [TCA_CODEL_TARGET]        = { .type = NETLINK_TYPE_U32 },
+        [TCA_CODEL_LIMIT]         = { .type = NETLINK_TYPE_U32 },
+        [TCA_CODEL_INTERVAL]      = { .type = NETLINK_TYPE_U32 },
+        [TCA_CODEL_ECN]           = { .type = NETLINK_TYPE_U32 },
+        [TCA_CODEL_CE_THRESHOLD]  = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_drr_types[] = {
+        [TCA_DRR_QUANTUM] = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_ets_quanta_types[] = {
+        [TCA_ETS_QUANTA_BAND] = { .type = NETLINK_TYPE_U32, },
+};
+
+static const NLTypeSystem rtnl_tca_option_data_ets_quanta_type_system = {
+        .count = ELEMENTSOF(rtnl_tca_option_data_ets_quanta_types),
+        .types = rtnl_tca_option_data_ets_quanta_types,
+};
+
+static const NLType rtnl_tca_option_data_ets_prio_types[] = {
+        [TCA_ETS_PRIOMAP_BAND] = { .type = NETLINK_TYPE_U8, },
+};
+
+static const NLTypeSystem rtnl_tca_option_data_ets_prio_type_system = {
+        .count = ELEMENTSOF(rtnl_tca_option_data_ets_prio_types),
+        .types = rtnl_tca_option_data_ets_prio_types,
+};
+
+static const NLType rtnl_tca_option_data_ets_types[] = {
+        [TCA_ETS_NBANDS]      = { .type = NETLINK_TYPE_U8 },
+        [TCA_ETS_NSTRICT]     = { .type = NETLINK_TYPE_U8 },
+        [TCA_ETS_QUANTA]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_option_data_ets_quanta_type_system },
+        [TCA_ETS_PRIOMAP]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_option_data_ets_prio_type_system },
+        [TCA_ETS_QUANTA_BAND] = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_fq_types[] = {
+        [TCA_FQ_PLIMIT]             = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_FLOW_PLIMIT]        = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_QUANTUM]            = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_INITIAL_QUANTUM]    = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_RATE_ENABLE]        = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_FLOW_DEFAULT_RATE]  = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_FLOW_MAX_RATE]      = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_BUCKETS_LOG]        = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_FLOW_REFILL_DELAY]  = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_LOW_RATE_THRESHOLD] = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CE_THRESHOLD]       = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_ORPHAN_MASK]        = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_fq_codel_types[] = {
+        [TCA_FQ_CODEL_TARGET]          = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_LIMIT]           = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_INTERVAL]        = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_ECN]             = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_FLOWS]           = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_QUANTUM]         = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_CE_THRESHOLD]    = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_DROP_BATCH_SIZE] = { .type = NETLINK_TYPE_U32 },
+        [TCA_FQ_CODEL_MEMORY_LIMIT]    = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_fq_pie_types[] = {
+        [TCA_FQ_PIE_LIMIT]   = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_gred_types[] = {
+        [TCA_GRED_DPS] = { .size = sizeof(struct tc_gred_sopt) },
+};
+
+static const NLType rtnl_tca_option_data_hhf_types[] = {
+        [TCA_HHF_BACKLOG_LIMIT] = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_htb_types[] = {
+        [TCA_HTB_PARMS]  = { .size = sizeof(struct tc_htb_opt) },
+        [TCA_HTB_INIT]   = { .size = sizeof(struct tc_htb_glob) },
+        [TCA_HTB_CTAB]   = { .size = TC_RTAB_SIZE },
+        [TCA_HTB_RTAB]   = { .size = TC_RTAB_SIZE },
+        [TCA_HTB_RATE64] = { .type = NETLINK_TYPE_U64 },
+        [TCA_HTB_CEIL64] = { .type = NETLINK_TYPE_U64 },
+};
+
+static const NLType rtnl_tca_option_data_pie_types[] = {
+        [TCA_PIE_LIMIT]   = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_qfq_types[] = {
+        [TCA_QFQ_WEIGHT] = { .type = NETLINK_TYPE_U32 },
+        [TCA_QFQ_LMAX]   = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLType rtnl_tca_option_data_sfb_types[] = {
+        [TCA_SFB_PARMS] = { .size = sizeof(struct tc_sfb_qopt) },
+};
+
+static const NLType rtnl_tca_option_data_tbf_types[] = {
+        [TCA_TBF_PARMS]   = { .size = sizeof(struct tc_tbf_qopt) },
+        [TCA_TBF_RTAB]    = { .size = TC_RTAB_SIZE },
+        [TCA_TBF_PTAB]    = { .size = TC_RTAB_SIZE },
+        [TCA_TBF_RATE64]  = { .type = NETLINK_TYPE_U64 },
+        [TCA_TBF_PRATE64] = { .type = NETLINK_TYPE_U64 },
+        [TCA_TBF_BURST]   = { .type = NETLINK_TYPE_U32 },
+        [TCA_TBF_PBURST]  = { .type = NETLINK_TYPE_U32 },
+};
+
+static const char* const nl_union_tca_option_data_table[] = {
+        [NL_UNION_TCA_OPTION_DATA_CAKE] = "cake",
+        [NL_UNION_TCA_OPTION_DATA_CODEL] = "codel",
+        [NL_UNION_TCA_OPTION_DATA_DRR] = "drr",
+        [NL_UNION_TCA_OPTION_DATA_ETS] = "ets",
+        [NL_UNION_TCA_OPTION_DATA_FQ] = "fq",
+        [NL_UNION_TCA_OPTION_DATA_FQ_CODEL] = "fq_codel",
+        [NL_UNION_TCA_OPTION_DATA_FQ_PIE] = "fq_pie",
+        [NL_UNION_TCA_OPTION_DATA_GRED] = "gred",
+        [NL_UNION_TCA_OPTION_DATA_HHF] = "hhf",
+        [NL_UNION_TCA_OPTION_DATA_HTB] = "htb",
+        [NL_UNION_TCA_OPTION_DATA_PIE] = "pie",
+        [NL_UNION_TCA_OPTION_DATA_QFQ] = "qfq",
+        [NL_UNION_TCA_OPTION_DATA_SFB] = "sfb",
+        [NL_UNION_TCA_OPTION_DATA_TBF] = "tbf",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(nl_union_tca_option_data, NLUnionTCAOptionData);
+
+static const NLTypeSystem rtnl_tca_option_data_type_systems[] = {
+        [NL_UNION_TCA_OPTION_DATA_CAKE] =        { .count = ELEMENTSOF(rtnl_tca_option_data_cake_types),
+                                                   .types = rtnl_tca_option_data_cake_types },
+        [NL_UNION_TCA_OPTION_DATA_CODEL] =       { .count = ELEMENTSOF(rtnl_tca_option_data_codel_types),
+                                                   .types = rtnl_tca_option_data_codel_types },
+        [NL_UNION_TCA_OPTION_DATA_DRR] =         { .count = ELEMENTSOF(rtnl_tca_option_data_drr_types),
+                                                   .types = rtnl_tca_option_data_drr_types },
+        [NL_UNION_TCA_OPTION_DATA_ETS] =         { .count = ELEMENTSOF(rtnl_tca_option_data_ets_types),
+                                                   .types = rtnl_tca_option_data_ets_types },
+        [NL_UNION_TCA_OPTION_DATA_FQ] =          { .count = ELEMENTSOF(rtnl_tca_option_data_fq_types),
+                                                   .types = rtnl_tca_option_data_fq_types },
+        [NL_UNION_TCA_OPTION_DATA_FQ_CODEL] =    { .count = ELEMENTSOF(rtnl_tca_option_data_fq_codel_types),
+                                                   .types = rtnl_tca_option_data_fq_codel_types },
+        [NL_UNION_TCA_OPTION_DATA_FQ_PIE] =      { .count = ELEMENTSOF(rtnl_tca_option_data_fq_pie_types),
+                                                   .types = rtnl_tca_option_data_fq_pie_types },
+        [NL_UNION_TCA_OPTION_DATA_GRED] =        { .count = ELEMENTSOF(rtnl_tca_option_data_gred_types),
+                                                   .types = rtnl_tca_option_data_gred_types },
+        [NL_UNION_TCA_OPTION_DATA_HHF] =         { .count = ELEMENTSOF(rtnl_tca_option_data_hhf_types),
+                                                   .types = rtnl_tca_option_data_hhf_types },
+        [NL_UNION_TCA_OPTION_DATA_HTB] =         { .count = ELEMENTSOF(rtnl_tca_option_data_htb_types),
+                                                   .types = rtnl_tca_option_data_htb_types },
+        [NL_UNION_TCA_OPTION_DATA_PIE] =         { .count = ELEMENTSOF(rtnl_tca_option_data_pie_types),
+                                                   .types = rtnl_tca_option_data_pie_types },
+        [NL_UNION_TCA_OPTION_DATA_QFQ] =         { .count = ELEMENTSOF(rtnl_tca_option_data_qfq_types),
+                                                   .types = rtnl_tca_option_data_qfq_types },
+        [NL_UNION_TCA_OPTION_DATA_SFB] =         { .count = ELEMENTSOF(rtnl_tca_option_data_sfb_types),
+                                                   .types = rtnl_tca_option_data_sfb_types },
+        [NL_UNION_TCA_OPTION_DATA_TBF] =         { .count = ELEMENTSOF(rtnl_tca_option_data_tbf_types),
+                                                   .types = rtnl_tca_option_data_tbf_types },
+};
+
+static const NLTypeSystemUnion rtnl_tca_option_data_type_system_union = {
+        .num = _NL_UNION_TCA_OPTION_DATA_MAX,
+        .lookup = nl_union_tca_option_data_from_string,
+        .type_systems = rtnl_tca_option_data_type_systems,
+        .match_type = NL_MATCH_SIBLING,
+        .match = TCA_KIND,
+};
+
+static const NLType rtnl_tca_types[] = {
+        [TCA_KIND]           = { .type = NETLINK_TYPE_STRING },
+        [TCA_OPTIONS]        = { .type = NETLINK_TYPE_UNION, .type_system_union = &rtnl_tca_option_data_type_system_union },
+        [TCA_INGRESS_BLOCK]  = { .type = NETLINK_TYPE_U32 },
+        [TCA_EGRESS_BLOCK]   = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem rtnl_tca_type_system = {
+        .count = ELEMENTSOF(rtnl_tca_types),
+        .types = rtnl_tca_types,
+};
+
+static const NLType mdb_types[] = {
+        [MDBA_SET_ENTRY]     = { .size = sizeof(struct br_port_msg) },
+};
+
+static const NLTypeSystem rtnl_mdb_type_system = {
+        .count = ELEMENTSOF(mdb_types),
+        .types = mdb_types,
+};
+
+static const NLType error_types[] = {
+        [NLMSGERR_ATTR_MSG]  = { .type = NETLINK_TYPE_STRING },
+        [NLMSGERR_ATTR_OFFS] = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem error_type_system = {
+        .count = ELEMENTSOF(error_types),
+        .types = error_types,
+};
+
+static const NLType rtnl_types[] = {
+        [NLMSG_DONE]       = { .type = NETLINK_TYPE_NESTED, .type_system = &empty_type_system, .size = 0 },
+        [NLMSG_ERROR]      = { .type = NETLINK_TYPE_NESTED, .type_system = &error_type_system, .size = sizeof(struct nlmsgerr) },
+        [RTM_NEWLINK]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_DELLINK]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_GETLINK]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_SETLINK]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_NEWLINKPROP]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_DELLINKPROP]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_GETLINKPROP]  = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_link_type_system, .size = sizeof(struct ifinfomsg) },
+        [RTM_NEWADDR]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_address_type_system, .size = sizeof(struct ifaddrmsg) },
+        [RTM_DELADDR]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_address_type_system, .size = sizeof(struct ifaddrmsg) },
+        [RTM_GETADDR]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_address_type_system, .size = sizeof(struct ifaddrmsg) },
+        [RTM_NEWROUTE]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_route_type_system, .size = sizeof(struct rtmsg) },
+        [RTM_DELROUTE]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_route_type_system, .size = sizeof(struct rtmsg) },
+        [RTM_GETROUTE]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_route_type_system, .size = sizeof(struct rtmsg) },
+        [RTM_NEWNEIGH]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_neigh_type_system, .size = sizeof(struct ndmsg) },
+        [RTM_DELNEIGH]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_neigh_type_system, .size = sizeof(struct ndmsg) },
+        [RTM_GETNEIGH]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_neigh_type_system, .size = sizeof(struct ndmsg) },
+        [RTM_NEWADDRLABEL] = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_addrlabel_type_system, .size = sizeof(struct ifaddrlblmsg) },
+        [RTM_DELADDRLABEL] = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_addrlabel_type_system, .size = sizeof(struct ifaddrlblmsg) },
+        [RTM_GETADDRLABEL] = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_addrlabel_type_system, .size = sizeof(struct ifaddrlblmsg) },
+        [RTM_NEWRULE]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_routing_policy_rule_type_system, .size = sizeof(struct rtmsg) },
+        [RTM_DELRULE]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_routing_policy_rule_type_system, .size = sizeof(struct rtmsg) },
+        [RTM_GETRULE]      = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_routing_policy_rule_type_system, .size = sizeof(struct rtmsg) },
+        [RTM_NEWNEXTHOP]   = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_nexthop_type_system, .size = sizeof(struct nhmsg) },
+        [RTM_DELNEXTHOP]   = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_nexthop_type_system, .size = sizeof(struct nhmsg) },
+        [RTM_GETNEXTHOP]   = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_nexthop_type_system, .size = sizeof(struct nhmsg) },
+        [RTM_NEWQDISC]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_type_system, .size = sizeof(struct tcmsg) },
+        [RTM_DELQDISC]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_type_system, .size = sizeof(struct tcmsg) },
+        [RTM_GETQDISC]     = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_type_system, .size = sizeof(struct tcmsg) },
+        [RTM_NEWTCLASS]    = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_type_system, .size = sizeof(struct tcmsg) },
+        [RTM_DELTCLASS]    = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_type_system, .size = sizeof(struct tcmsg) },
+        [RTM_GETTCLASS]    = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_tca_type_system, .size = sizeof(struct tcmsg) },
+        [RTM_NEWMDB]       = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_mdb_type_system, .size = sizeof(struct br_port_msg) },
+        [RTM_DELMDB]       = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_mdb_type_system, .size = sizeof(struct br_port_msg) },
+        [RTM_GETMDB]       = { .type = NETLINK_TYPE_NESTED, .type_system = &rtnl_mdb_type_system, .size = sizeof(struct br_port_msg) },
+};
+
+const NLTypeSystem rtnl_type_system_root = {
+        .count = ELEMENTSOF(rtnl_types),
+        .types = rtnl_types,
+};
+
+static const NLType genl_wireguard_allowedip_types[] = {
+        [WGALLOWEDIP_A_FAMILY] = { .type = NETLINK_TYPE_U16 },
+        [WGALLOWEDIP_A_IPADDR] = { .type = NETLINK_TYPE_IN_ADDR },
+        [WGALLOWEDIP_A_CIDR_MASK] = { .type = NETLINK_TYPE_U8 },
+};
+
+static const NLTypeSystem genl_wireguard_allowedip_type_system = {
+        .count = ELEMENTSOF(genl_wireguard_allowedip_types),
+        .types = genl_wireguard_allowedip_types,
+};
+
+static const NLType genl_wireguard_peer_types[] = {
+        [WGPEER_A_PUBLIC_KEY] = { .size = WG_KEY_LEN  },
+        [WGPEER_A_FLAGS] = { .type = NETLINK_TYPE_U32 },
+        [WGPEER_A_PRESHARED_KEY] = { .size = WG_KEY_LEN },
+        [WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL] = { .type = NETLINK_TYPE_U16 },
+        [WGPEER_A_ENDPOINT] = { .type = NETLINK_TYPE_SOCKADDR },
+        [WGPEER_A_ALLOWEDIPS] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_wireguard_allowedip_type_system },
+};
+
+static const NLTypeSystem genl_wireguard_peer_type_system = {
+        .count = ELEMENTSOF(genl_wireguard_peer_types),
+        .types = genl_wireguard_peer_types,
+};
+
+static const NLType genl_wireguard_set_device_types[] = {
+        [WGDEVICE_A_IFINDEX] = { .type = NETLINK_TYPE_U32 },
+        [WGDEVICE_A_IFNAME] = { .type = NETLINK_TYPE_STRING, .size = IFNAMSIZ-1 },
+        [WGDEVICE_A_FLAGS] = { .type = NETLINK_TYPE_U32 },
+        [WGDEVICE_A_PRIVATE_KEY] = { .size = WG_KEY_LEN },
+        [WGDEVICE_A_LISTEN_PORT] = { .type = NETLINK_TYPE_U16 },
+        [WGDEVICE_A_FWMARK] = { .type = NETLINK_TYPE_U32 },
+        [WGDEVICE_A_PEERS] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_wireguard_peer_type_system },
+};
+
+static const NLTypeSystem genl_wireguard_set_device_type_system = {
+        .count = ELEMENTSOF(genl_wireguard_set_device_types),
+        .types = genl_wireguard_set_device_types,
+};
+
+static const NLType genl_wireguard_cmds[] = {
+        [WG_CMD_SET_DEVICE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_wireguard_set_device_type_system },
+};
+
+static const NLTypeSystem genl_wireguard_type_system = {
+        .count = ELEMENTSOF(genl_wireguard_cmds),
+        .types = genl_wireguard_cmds,
+};
+
+static const NLType genl_mcast_group_types[] = {
+        [CTRL_ATTR_MCAST_GRP_NAME]  = { .type = NETLINK_TYPE_STRING },
+        [CTRL_ATTR_MCAST_GRP_ID]    = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem genl_mcast_group_type_system = {
+        .count = ELEMENTSOF(genl_mcast_group_types),
+        .types = genl_mcast_group_types,
+};
+
+static const NLType genl_get_family_types[] = {
+        [CTRL_ATTR_FAMILY_NAME]  = { .type = NETLINK_TYPE_STRING },
+        [CTRL_ATTR_FAMILY_ID]    = { .type = NETLINK_TYPE_U16 },
+        [CTRL_ATTR_MCAST_GROUPS] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_mcast_group_type_system },
+};
+
+static const NLTypeSystem genl_get_family_type_system = {
+        .count = ELEMENTSOF(genl_get_family_types),
+        .types = genl_get_family_types,
+};
+
+static const NLType genl_ctrl_id_ctrl_cmds[] = {
+        [CTRL_CMD_GETFAMILY] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_get_family_type_system },
+};
+
+static const NLTypeSystem genl_ctrl_id_ctrl_type_system = {
+        .count = ELEMENTSOF(genl_ctrl_id_ctrl_cmds),
+        .types = genl_ctrl_id_ctrl_cmds,
+};
+
+static const NLType genl_fou_types[] = {
+        [FOU_ATTR_PORT]              = { .type = NETLINK_TYPE_U16 },
+        [FOU_ATTR_AF]                = { .type = NETLINK_TYPE_U8 },
+        [FOU_ATTR_IPPROTO]           = { .type = NETLINK_TYPE_U8 },
+        [FOU_ATTR_TYPE]              = { .type = NETLINK_TYPE_U8 },
+        [FOU_ATTR_REMCSUM_NOPARTIAL] = { .type = NETLINK_TYPE_FLAG },
+        [FOU_ATTR_LOCAL_V4]          = { .type = NETLINK_TYPE_IN_ADDR },
+        [FOU_ATTR_PEER_V4]           = { .type = NETLINK_TYPE_IN_ADDR },
+        [FOU_ATTR_LOCAL_V6]          = { .type = NETLINK_TYPE_IN_ADDR },
+        [FOU_ATTR_PEER_V6]           = { .type = NETLINK_TYPE_IN_ADDR},
+        [FOU_ATTR_PEER_PORT]         = { .type = NETLINK_TYPE_U16},
+        [FOU_ATTR_IFINDEX]           = { .type = NETLINK_TYPE_U32},
+};
+
+static const NLTypeSystem genl_fou_type_system = {
+        .count = ELEMENTSOF(genl_fou_types),
+        .types = genl_fou_types,
+};
+
+static const NLType genl_fou_cmds[] = {
+        [FOU_CMD_ADD] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_fou_type_system },
+        [FOU_CMD_DEL] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_fou_type_system },
+        [FOU_CMD_GET] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_fou_type_system },
+};
+
+static const NLTypeSystem genl_fou_cmds_type_system = {
+        .count = ELEMENTSOF(genl_fou_cmds),
+        .types = genl_fou_cmds,
+};
+
+static const NLType genl_l2tp_types[] = {
+        [L2TP_ATTR_PW_TYPE]           = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_ENCAP_TYPE]        = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_OFFSET]            = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_DATA_SEQ]          = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_L2SPEC_TYPE]       = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_L2SPEC_LEN]        = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_PROTO_VERSION]     = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_IFNAME]            = { .type = NETLINK_TYPE_STRING },
+        [L2TP_ATTR_CONN_ID]           = { .type = NETLINK_TYPE_U32 },
+        [L2TP_ATTR_PEER_CONN_ID]      = { .type = NETLINK_TYPE_U32 },
+        [L2TP_ATTR_SESSION_ID]        = { .type = NETLINK_TYPE_U32 },
+        [L2TP_ATTR_PEER_SESSION_ID]   = { .type = NETLINK_TYPE_U32 },
+        [L2TP_ATTR_UDP_CSUM]          = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_VLAN_ID]           = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_RECV_SEQ]          = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_SEND_SEQ]          = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_LNS_MODE]          = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_USING_IPSEC]       = { .type = NETLINK_TYPE_U8 },
+        [L2TP_ATTR_FD]                = { .type = NETLINK_TYPE_U32 },
+        [L2TP_ATTR_IP_SADDR]          = { .type = NETLINK_TYPE_IN_ADDR },
+        [L2TP_ATTR_IP_DADDR]          = { .type = NETLINK_TYPE_IN_ADDR },
+        [L2TP_ATTR_UDP_SPORT]         = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_UDP_DPORT]         = { .type = NETLINK_TYPE_U16 },
+        [L2TP_ATTR_IP6_SADDR]         = { .type = NETLINK_TYPE_IN_ADDR },
+        [L2TP_ATTR_IP6_DADDR]         = { .type = NETLINK_TYPE_IN_ADDR },
+        [L2TP_ATTR_UDP_ZERO_CSUM6_TX] = { .type = NETLINK_TYPE_FLAG },
+        [L2TP_ATTR_UDP_ZERO_CSUM6_RX] = { .type = NETLINK_TYPE_FLAG },
+};
+
+static const NLTypeSystem genl_l2tp_type_system = {
+        .count = ELEMENTSOF(genl_l2tp_types),
+        .types = genl_l2tp_types,
+};
+
+static const NLType genl_l2tp[]   = {
+        [L2TP_CMD_TUNNEL_CREATE]  = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_TUNNEL_DELETE]  = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_TUNNEL_MODIFY]  = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_TUNNEL_GET]     = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_SESSION_CREATE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_SESSION_DELETE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_SESSION_MODIFY] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+        [L2TP_CMD_SESSION_GET]    = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_type_system },
+};
+
+static const NLTypeSystem genl_l2tp_tunnel_session_type_system = {
+        .count = ELEMENTSOF(genl_l2tp),
+        .types = genl_l2tp,
+};
+
+static const NLType genl_rxsc_types[] = {
+        [MACSEC_RXSC_ATTR_SCI] = { .type = NETLINK_TYPE_U64 },
+};
+
+static const NLTypeSystem genl_rxsc_config_type_system = {
+        .count = ELEMENTSOF(genl_rxsc_types),
+        .types = genl_rxsc_types,
+};
+
+static const NLType genl_macsec_rxsc_types[] = {
+        [MACSEC_ATTR_IFINDEX]     = { .type = NETLINK_TYPE_U32 },
+        [MACSEC_ATTR_RXSC_CONFIG] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_rxsc_config_type_system },
+};
+
+static const NLTypeSystem genl_macsec_rxsc_type_system = {
+        .count = ELEMENTSOF(genl_macsec_rxsc_types),
+        .types = genl_macsec_rxsc_types,
+};
+
+static const NLType genl_macsec_sa_config_types[] = {
+        [MACSEC_SA_ATTR_AN]     = { .type = NETLINK_TYPE_U8 },
+        [MACSEC_SA_ATTR_ACTIVE] = { .type = NETLINK_TYPE_U8 },
+        [MACSEC_SA_ATTR_PN]     = { .type = NETLINK_TYPE_U32 },
+        [MACSEC_SA_ATTR_KEYID]  = { .size = MACSEC_KEYID_LEN },
+        [MACSEC_SA_ATTR_KEY]    = { .size = MACSEC_MAX_KEY_LEN },
+};
+
+static const NLTypeSystem genl_macsec_sa_config_type_system = {
+        .count = ELEMENTSOF(genl_macsec_sa_config_types),
+        .types = genl_macsec_sa_config_types,
+};
+
+static const NLType genl_macsec_rxsa_types[] = {
+        [MACSEC_ATTR_IFINDEX]   = { .type = NETLINK_TYPE_U32 },
+        [MACSEC_ATTR_SA_CONFIG] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_macsec_sa_config_type_system },
+};
+
+static const NLTypeSystem genl_macsec_rxsa_type_system = {
+        .count = ELEMENTSOF(genl_macsec_rxsa_types),
+        .types = genl_macsec_rxsa_types,
+};
+
+static const NLType genl_macsec_sa_types[] = {
+        [MACSEC_ATTR_IFINDEX]     = { .type = NETLINK_TYPE_U32 },
+        [MACSEC_ATTR_RXSC_CONFIG] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_rxsc_config_type_system },
+        [MACSEC_ATTR_SA_CONFIG]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_macsec_sa_config_type_system },
+};
+
+static const NLTypeSystem genl_macsec_sa_type_system = {
+        .count = ELEMENTSOF(genl_macsec_sa_types),
+        .types = genl_macsec_sa_types,
+};
+
+static const NLType genl_macsec[]   = {
+        [MACSEC_CMD_ADD_RXSC]  = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_macsec_rxsc_type_system },
+        [MACSEC_CMD_ADD_TXSA]  = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_macsec_rxsa_type_system},
+        [MACSEC_CMD_ADD_RXSA]  = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_macsec_sa_type_system },
+};
+
+static const NLTypeSystem genl_macsec_device_type_system = {
+        .count = ELEMENTSOF(genl_macsec),
+        .types = genl_macsec,
+};
+
+static const NLType genl_nl80211_types[] = {
+        [NL80211_ATTR_IFINDEX] = { .type = NETLINK_TYPE_U32 },
+        [NL80211_ATTR_MAC]     = { .type = NETLINK_TYPE_ETHER_ADDR },
+        [NL80211_ATTR_SSID]    = { .type = NETLINK_TYPE_STRING },
+        [NL80211_ATTR_IFTYPE]  = { .type = NETLINK_TYPE_U32 },
+};
+
+static const NLTypeSystem genl_nl80211_type_system = {
+        .count = ELEMENTSOF(genl_nl80211_types),
+        .types = genl_nl80211_types,
+};
+
+static const NLType genl_nl80211_cmds[] = {
+        [NL80211_CMD_GET_WIPHY]     = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_SET_WIPHY]     = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_NEW_WIPHY]     = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_DEL_WIPHY]     = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_GET_INTERFACE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_SET_INTERFACE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_NEW_INTERFACE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_DEL_INTERFACE] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_GET_STATION]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_SET_STATION]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_NEW_STATION]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+        [NL80211_CMD_DEL_STATION]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system },
+};
+
+static const NLTypeSystem genl_nl80211_cmds_type_system = {
+        .count = ELEMENTSOF(genl_nl80211_cmds),
+        .types = genl_nl80211_cmds,
+};
+
+static const NLType genl_families[] = {
+        [SD_GENL_ID_CTRL]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_ctrl_id_ctrl_type_system },
+        [SD_GENL_WIREGUARD] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_wireguard_type_system },
+        [SD_GENL_FOU]       = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_fou_cmds_type_system },
+        [SD_GENL_L2TP]      = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_l2tp_tunnel_session_type_system },
+        [SD_GENL_MACSEC]    = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_macsec_device_type_system },
+        [SD_GENL_NL80211]   = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_cmds_type_system },
+};
+
+/* Mainly used when sending message */
+const NLTypeSystem genl_family_type_system_root = {
+        .count = ELEMENTSOF(genl_families),
+        .types = genl_families,
+};
+
+static const NLType genl_types[] = {
+        [SD_GENL_ERROR]   = { .type = NETLINK_TYPE_NESTED, .type_system = &error_type_system, .size = sizeof(struct nlmsgerr) },
+        [SD_GENL_DONE]    = { .type = NETLINK_TYPE_NESTED, .type_system = &empty_type_system },
+        [SD_GENL_ID_CTRL] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_get_family_type_system, .size = sizeof(struct genlmsghdr) },
+        [SD_GENL_NL80211] = { .type = NETLINK_TYPE_NESTED, .type_system = &genl_nl80211_type_system, .size = sizeof(struct genlmsghdr) },
+};
+
+/* Mainly used when message received */
+const NLTypeSystem genl_type_system_root = {
+        .count = ELEMENTSOF(genl_types),
+        .types = genl_types,
+};
+
+uint16_t type_get_type(const NLType *type) {
+        assert(type);
+        return type->type;
+}
+
+size_t type_get_size(const NLType *type) {
+        assert(type);
+        return type->size;
+}
+
+void type_get_type_system(const NLType *nl_type, const NLTypeSystem **ret) {
+        assert(nl_type);
+        assert(ret);
+        assert(nl_type->type == NETLINK_TYPE_NESTED);
+        assert(nl_type->type_system);
+
+        *ret = nl_type->type_system;
+}
+
+void type_get_type_system_union(const NLType *nl_type, const NLTypeSystemUnion **ret) {
+        assert(nl_type);
+        assert(ret);
+        assert(nl_type->type == NETLINK_TYPE_UNION);
+        assert(nl_type->type_system_union);
+
+        *ret = nl_type->type_system_union;
+}
+
+uint16_t type_system_get_count(const NLTypeSystem *type_system) {
+        assert(type_system);
+        return type_system->count;
+}
+
+const NLTypeSystem *type_system_get_root(int protocol) {
+        switch (protocol) {
+                case NETLINK_GENERIC:
+                        return &genl_type_system_root;
+                default: /* NETLINK_ROUTE: */
+                        return &rtnl_type_system_root;
+        }
+}
+
+int type_system_root_get_type(sd_netlink *nl, const NLType **ret, uint16_t type) {
+        sd_genl_family family;
+        const NLType *nl_type;
+        int r;
+
+        if (!nl || nl->protocol != NETLINK_GENERIC)
+                return type_system_get_type(&rtnl_type_system_root, ret, type);
+
+        r = nlmsg_type_to_genl_family(nl, type, &family);
+        if (r < 0)
+                return r;
+
+        if (family >= genl_type_system_root.count)
+                return -EOPNOTSUPP;
+
+        nl_type = &genl_type_system_root.types[family];
+
+        if (nl_type->type == NETLINK_TYPE_UNSPEC)
+                return -EOPNOTSUPP;
+
+        *ret = nl_type;
+
+        return 0;
+}
+
+int type_system_get_type(const NLTypeSystem *type_system, const NLType **ret, uint16_t type) {
+        const NLType *nl_type;
+
+        assert(ret);
+        assert(type_system);
+        assert(type_system->types);
+
+        if (type >= type_system->count)
+                return -EOPNOTSUPP;
+
+        nl_type = &type_system->types[type];
+
+        if (nl_type->type == NETLINK_TYPE_UNSPEC)
+                return -EOPNOTSUPP;
+
+        *ret = nl_type;
+
+        return 0;
+}
+
+int type_system_get_type_system(const NLTypeSystem *type_system, const NLTypeSystem **ret, uint16_t type) {
+        const NLType *nl_type;
+        int r;
+
+        assert(ret);
+
+        r = type_system_get_type(type_system, &nl_type, type);
+        if (r < 0)
+                return r;
+
+        type_get_type_system(nl_type, ret);
+        return 0;
+}
+
+int type_system_get_type_system_union(const NLTypeSystem *type_system, const NLTypeSystemUnion **ret, uint16_t type) {
+        const NLType *nl_type;
+        int r;
+
+        assert(ret);
+
+        r = type_system_get_type(type_system, &nl_type, type);
+        if (r < 0)
+                return r;
+
+        type_get_type_system_union(nl_type, ret);
+        return 0;
+}
+
+int type_system_union_get_type_system(const NLTypeSystemUnion *type_system_union, const NLTypeSystem **ret, const char *key) {
+        int type;
+
+        assert(type_system_union);
+        assert(type_system_union->match_type == NL_MATCH_SIBLING);
+        assert(type_system_union->lookup);
+        assert(type_system_union->type_systems);
+        assert(ret);
+        assert(key);
+
+        type = type_system_union->lookup(key);
+        if (type < 0)
+                return -EOPNOTSUPP;
+
+        assert(type < type_system_union->num);
+
+        *ret = &type_system_union->type_systems[type];
+
+        return 0;
+}
+
+int type_system_union_protocol_get_type_system(const NLTypeSystemUnion *type_system_union, const NLTypeSystem **ret, uint16_t protocol) {
+        const NLTypeSystem *type_system;
+
+        assert(type_system_union);
+        assert(type_system_union->type_systems);
+        assert(type_system_union->match_type == NL_MATCH_PROTOCOL);
+        assert(ret);
+
+        if (protocol >= type_system_union->num)
+                return -EOPNOTSUPP;
+
+        type_system = &type_system_union->type_systems[protocol];
+        if (!type_system->types)
+                return -EOPNOTSUPP;
+
+        *ret = type_system;
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-netlink/netlink-types.h b/src/libsystemd/sd-netlink/netlink-types.h
new file mode 100644
index 0000000..b14e66f
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-types.h
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "macro.h"
+
+enum {
+        NETLINK_TYPE_UNSPEC,
+        NETLINK_TYPE_U8,                        /* NLA_U8 */
+        NETLINK_TYPE_U16,                       /* NLA_U16 */
+        NETLINK_TYPE_U32,                       /* NLA_U32 */
+        NETLINK_TYPE_U64,                       /* NLA_U64 */
+        NETLINK_TYPE_S8,                        /* NLA_S8 */
+        NETLINK_TYPE_S16,                       /* NLA_S16 */
+        NETLINK_TYPE_S32,                       /* NLA_S32 */
+        NETLINK_TYPE_S64,                       /* NLA_S64 */
+        NETLINK_TYPE_STRING,                    /* NLA_STRING */
+        NETLINK_TYPE_FLAG,                      /* NLA_FLAG */
+        NETLINK_TYPE_IN_ADDR,
+        NETLINK_TYPE_ETHER_ADDR,
+        NETLINK_TYPE_CACHE_INFO,
+        NETLINK_TYPE_NESTED,                    /* NLA_NESTED */
+        NETLINK_TYPE_UNION,
+        NETLINK_TYPE_SOCKADDR,
+};
+
+typedef enum NLMatchType {
+        NL_MATCH_SIBLING,
+        NL_MATCH_PROTOCOL,
+} NLMatchType;
+
+typedef struct NLTypeSystemUnion NLTypeSystemUnion;
+typedef struct NLTypeSystem NLTypeSystem;
+typedef struct NLType NLType;
+
+struct NLTypeSystemUnion {
+        int num;
+        NLMatchType match_type;
+        uint16_t match;
+        int (*lookup)(const char *);
+        const NLTypeSystem *type_systems;
+};
+
+extern const NLTypeSystem genl_family_type_system_root;
+
+uint16_t type_get_type(const NLType *type);
+size_t type_get_size(const NLType *type);
+void type_get_type_system(const NLType *type, const NLTypeSystem **ret);
+void type_get_type_system_union(const NLType *type, const NLTypeSystemUnion **ret);
+
+const NLTypeSystem* type_system_get_root(int protocol);
+uint16_t type_system_get_count(const NLTypeSystem *type_system);
+int type_system_root_get_type(sd_netlink *nl, const NLType **ret, uint16_t type);
+int type_system_get_type(const NLTypeSystem *type_system, const NLType **ret, uint16_t type);
+int type_system_get_type_system(const NLTypeSystem *type_system, const NLTypeSystem **ret, uint16_t type);
+int type_system_get_type_system_union(const NLTypeSystem *type_system, const NLTypeSystemUnion **ret, uint16_t type);
+int type_system_union_get_type_system(const NLTypeSystemUnion *type_system_union, const NLTypeSystem **ret, const char *key);
+int type_system_union_protocol_get_type_system(const NLTypeSystemUnion *type_system_union, const NLTypeSystem **ret, uint16_t protocol);
+
+typedef enum NLUnionLinkInfoData {
+        NL_UNION_LINK_INFO_DATA_BOND,
+        NL_UNION_LINK_INFO_DATA_BRIDGE,
+        NL_UNION_LINK_INFO_DATA_VLAN,
+        NL_UNION_LINK_INFO_DATA_VETH,
+        NL_UNION_LINK_INFO_DATA_DUMMY,
+        NL_UNION_LINK_INFO_DATA_MACVLAN,
+        NL_UNION_LINK_INFO_DATA_MACVTAP,
+        NL_UNION_LINK_INFO_DATA_IPVLAN,
+        NL_UNION_LINK_INFO_DATA_IPVTAP,
+        NL_UNION_LINK_INFO_DATA_VXLAN,
+        NL_UNION_LINK_INFO_DATA_IPIP_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_IPGRE_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_ERSPAN,
+        NL_UNION_LINK_INFO_DATA_IPGRETAP_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_IP6GRE_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_IP6GRETAP_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_SIT_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_VTI_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_VTI6_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_IP6TNL_TUNNEL,
+        NL_UNION_LINK_INFO_DATA_VRF,
+        NL_UNION_LINK_INFO_DATA_VCAN,
+        NL_UNION_LINK_INFO_DATA_GENEVE,
+        NL_UNION_LINK_INFO_DATA_VXCAN,
+        NL_UNION_LINK_INFO_DATA_WIREGUARD,
+        NL_UNION_LINK_INFO_DATA_NETDEVSIM,
+        NL_UNION_LINK_INFO_DATA_CAN,
+        NL_UNION_LINK_INFO_DATA_MACSEC,
+        NL_UNION_LINK_INFO_DATA_NLMON,
+        NL_UNION_LINK_INFO_DATA_XFRM,
+        NL_UNION_LINK_INFO_DATA_IFB,
+        NL_UNION_LINK_INFO_DATA_BAREUDP,
+        _NL_UNION_LINK_INFO_DATA_MAX,
+        _NL_UNION_LINK_INFO_DATA_INVALID = -1
+} NLUnionLinkInfoData;
+
+const char *nl_union_link_info_data_to_string(NLUnionLinkInfoData p) _const_;
+NLUnionLinkInfoData nl_union_link_info_data_from_string(const char *p) _pure_;
+
+typedef enum NLUnionTCAOptionData {
+        NL_UNION_TCA_OPTION_DATA_CAKE,
+        NL_UNION_TCA_OPTION_DATA_CODEL,
+        NL_UNION_TCA_OPTION_DATA_DRR,
+        NL_UNION_TCA_OPTION_DATA_ETS,
+        NL_UNION_TCA_OPTION_DATA_FQ,
+        NL_UNION_TCA_OPTION_DATA_FQ_CODEL,
+        NL_UNION_TCA_OPTION_DATA_FQ_PIE,
+        NL_UNION_TCA_OPTION_DATA_GRED,
+        NL_UNION_TCA_OPTION_DATA_HHF,
+        NL_UNION_TCA_OPTION_DATA_HTB,
+        NL_UNION_TCA_OPTION_DATA_PIE,
+        NL_UNION_TCA_OPTION_DATA_QFQ,
+        NL_UNION_TCA_OPTION_DATA_SFB,
+        NL_UNION_TCA_OPTION_DATA_TBF,
+        _NL_UNION_TCA_OPTION_DATA_MAX,
+        _NL_UNION_TCA_OPTION_DATA_INVALID = -1,
+} NLUnionTCAOptionData;
+
+const char *nl_union_tca_option_data_to_string(NLUnionTCAOptionData p) _const_;
+NLUnionTCAOptionData nl_union_tca_option_data_from_string(const char *p) _pure_;
diff --git a/src/libsystemd/sd-netlink/netlink-util.c b/src/libsystemd/sd-netlink/netlink-util.c
new file mode 100644
index 0000000..09e2158
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-util.c
@@ -0,0 +1,447 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-netlink.h"
+
+#include "format-util.h"
+#include "memory-util.h"
+#include "netlink-internal.h"
+#include "netlink-util.h"
+#include "strv.h"
+
+int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
+        _cleanup_strv_free_ char **alternative_names = NULL;
+        char old_name[IF_NAMESIZE + 1] = {};
+        int r;
+
+        assert(rtnl);
+        assert(ifindex > 0);
+        assert(name);
+
+        if (!ifname_valid(name))
+                return -EINVAL;
+
+        r = rtnl_get_link_alternative_names(rtnl, ifindex, &alternative_names);
+        if (r < 0)
+                log_debug_errno(r, "Failed to get alternative names on network interface %i, ignoring: %m",
+                                ifindex);
+
+        if (strv_contains(alternative_names, name)) {
+                r = rtnl_delete_link_alternative_names(rtnl, ifindex, STRV_MAKE(name));
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to remove '%s' from alternative names on network interface %i: %m",
+                                               name, ifindex);
+
+                format_ifname(ifindex, old_name);
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_SETLINK, ifindex);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_string(message, IFLA_IFNAME, name);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, NULL);
+        if (r < 0)
+                return r;
+
+        if (!isempty(old_name)) {
+                r = rtnl_set_link_alternative_names(rtnl, ifindex, STRV_MAKE(old_name));
+                if (r < 0)
+                        log_debug_errno(r, "Failed to set '%s' as an alternative name on network interface %i, ignoring: %m",
+                                        old_name, ifindex);
+        }
+
+        return 0;
+}
+
+int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias,
+                             const struct ether_addr *mac, uint32_t mtu) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
+        int r;
+
+        assert(rtnl);
+        assert(ifindex > 0);
+
+        if (!alias && !mac && mtu == 0)
+                return 0;
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_SETLINK, ifindex);
+        if (r < 0)
+                return r;
+
+        if (alias) {
+                r = sd_netlink_message_append_string(message, IFLA_IFALIAS, alias);
+                if (r < 0)
+                        return r;
+        }
+
+        if (mac) {
+                r = sd_netlink_message_append_ether_addr(message, IFLA_ADDRESS, mac);
+                if (r < 0)
+                        return r;
+        }
+
+        if (mtu != 0) {
+                r = sd_netlink_message_append_u32(message, IFLA_MTU, mtu);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_netlink_call(*rtnl, message, 0, NULL);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int rtnl_get_link_alternative_names(sd_netlink **rtnl, int ifindex, char ***ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL;
+        _cleanup_strv_free_ char **names = NULL;
+        int r;
+
+        assert(rtnl);
+        assert(ifindex > 0);
+        assert(ret);
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, ifindex);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_read_strv(reply, IFLA_PROP_LIST, IFLA_ALT_IFNAME, &names);
+        if (r < 0 && r != -ENODATA)
+                return r;
+
+        *ret = TAKE_PTR(names);
+
+        return 0;
+}
+
+static int rtnl_update_link_alternative_names(sd_netlink **rtnl, uint16_t nlmsg_type, int ifindex, char * const *alternative_names) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
+        int r;
+
+        assert(rtnl);
+        assert(ifindex > 0);
+        assert(IN_SET(nlmsg_type, RTM_NEWLINKPROP, RTM_DELLINKPROP));
+
+        if (strv_isempty(alternative_names))
+                return 0;
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, nlmsg_type, ifindex);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_open_container(message, IFLA_PROP_LIST);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_strv(message, IFLA_ALT_IFNAME, alternative_names);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_close_container(message);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, NULL);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names) {
+        return rtnl_update_link_alternative_names(rtnl, RTM_NEWLINKPROP, ifindex, alternative_names);
+}
+
+int rtnl_delete_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names) {
+        return rtnl_update_link_alternative_names(rtnl, RTM_DELLINKPROP, ifindex, alternative_names);
+}
+
+int rtnl_set_link_alternative_names_by_ifname(sd_netlink **rtnl, const char *ifname, char * const *alternative_names) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
+        int r;
+
+        assert(rtnl);
+        assert(ifname);
+
+        if (strv_isempty(alternative_names))
+                return 0;
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_NEWLINKPROP, 0);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_string(message, IFLA_IFNAME, ifname);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_open_container(message, IFLA_PROP_LIST);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_strv(message, IFLA_ALT_IFNAME, alternative_names);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_close_container(message);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, NULL);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int rtnl_resolve_link_alternative_name(sd_netlink **rtnl, const char *name) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *our_rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL;
+        int r, ret;
+
+        assert(name);
+
+        if (!rtnl)
+                rtnl = &our_rtnl;
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, 0);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_message_append_string(message, IFLA_ALT_IFNAME, name);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, &reply);
+        if (r == -EINVAL)
+                return -ENODEV; /* The device doesn't exist */
+        if (r < 0)
+                return r;
+
+        r = sd_rtnl_message_link_get_ifindex(reply, &ret);
+        if (r < 0)
+                return r;
+        assert(ret > 0);
+        return ret;
+}
+
+int rtnl_get_link_iftype(sd_netlink **rtnl, int ifindex, unsigned short *ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL, *reply = NULL;
+        int r;
+
+        if (!*rtnl) {
+                r = sd_netlink_open(rtnl);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_GETLINK, ifindex);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_call(*rtnl, message, 0, &reply);
+        if (r == -EINVAL)
+                return -ENODEV; /* The device does not exist */
+        if (r < 0)
+                return r;
+
+        return sd_rtnl_message_link_get_type(reply, ret);
+}
+
+int rtnl_message_new_synthetic_error(sd_netlink *rtnl, int error, uint32_t serial, sd_netlink_message **ret) {
+        struct nlmsgerr *err;
+        int r;
+
+        assert(error <= 0);
+
+        r = message_new(rtnl, ret, NLMSG_ERROR);
+        if (r < 0)
+                return r;
+
+        rtnl_message_seal(*ret);
+        (*ret)->hdr->nlmsg_seq = serial;
+
+        err = NLMSG_DATA((*ret)->hdr);
+        err->error = error;
+
+        return 0;
+}
+
+int rtnl_log_parse_error(int r) {
+        return log_error_errno(r, "Failed to parse netlink message: %m");
+}
+
+int rtnl_log_create_error(int r) {
+        return log_error_errno(r, "Failed to create netlink message: %m");
+}
+
+void rtattr_append_attribute_internal(struct rtattr *rta, unsigned short type, const void *data, size_t data_length) {
+        size_t padding_length;
+        uint8_t *padding;
+
+        assert(rta);
+        assert(!data || data_length > 0);
+
+        /* fill in the attribute */
+        rta->rta_type = type;
+        rta->rta_len = RTA_LENGTH(data_length);
+        if (data)
+                /* we don't deal with the case where the user lies about the type
+                 * and gives us too little data (so don't do that)
+                 */
+                padding = mempcpy(RTA_DATA(rta), data, data_length);
+
+        else
+                /* if no data was passed, make sure we still initialize the padding
+                   note that we can have data_length > 0 (used by some containers) */
+                padding = RTA_DATA(rta);
+
+        /* make sure also the padding at the end of the message is initialized */
+        padding_length = (uint8_t *) rta + RTA_SPACE(data_length) - padding;
+        memzero(padding, padding_length);
+}
+
+int rtattr_append_attribute(struct rtattr **rta, unsigned short type, const void *data, size_t data_length) {
+        struct rtattr *new_rta, *sub_rta;
+        size_t message_length;
+
+        assert(rta);
+        assert(!data || data_length > 0);
+
+        /* get the new message size (with padding at the end) */
+        message_length = RTA_ALIGN(rta ? (*rta)->rta_len : 0) + RTA_SPACE(data_length);
+
+        /* buffer should be smaller than both one page or 8K to be accepted by the kernel */
+        if (message_length > MIN(page_size(), 8192UL))
+                return -ENOBUFS;
+
+        /* realloc to fit the new attribute */
+        new_rta = realloc(*rta, message_length);
+        if (!new_rta)
+                return -ENOMEM;
+        *rta = new_rta;
+
+        /* get pointer to the attribute we are about to add */
+        sub_rta = (struct rtattr *) ((uint8_t *) *rta + RTA_ALIGN((*rta)->rta_len));
+
+        rtattr_append_attribute_internal(sub_rta, type, data, data_length);
+
+        /* update rta_len */
+        (*rta)->rta_len = message_length;
+
+        return 0;
+}
+
+int rtattr_read_nexthop(const struct rtnexthop *rtnh, size_t size, int family, OrderedSet **ret) {
+        _cleanup_ordered_set_free_free_ OrderedSet *set = NULL;
+        int r;
+
+        assert(rtnh);
+        assert(IN_SET(family, AF_INET, AF_INET6));
+
+        if (size < sizeof(struct rtnexthop))
+                return -EBADMSG;
+
+        for (; size >= sizeof(struct rtnexthop); ) {
+                _cleanup_free_ MultipathRoute *m = NULL;
+
+                if (NLMSG_ALIGN(rtnh->rtnh_len) > size)
+                        return -EBADMSG;
+
+                if (rtnh->rtnh_len < sizeof(struct rtnexthop))
+                        return -EBADMSG;
+
+                m = new(MultipathRoute, 1);
+                if (!m)
+                        return -ENOMEM;
+
+                *m = (MultipathRoute) {
+                        .ifindex = rtnh->rtnh_ifindex,
+                        .weight = rtnh->rtnh_hops == 0 ? 0 : rtnh->rtnh_hops + 1,
+                };
+
+                if (rtnh->rtnh_len > sizeof(struct rtnexthop)) {
+                        size_t len = rtnh->rtnh_len - sizeof(struct rtnexthop);
+
+                        for (struct rtattr *attr = RTNH_DATA(rtnh); RTA_OK(attr, len); attr = RTA_NEXT(attr, len)) {
+                                if (attr->rta_type == RTA_GATEWAY) {
+                                        if (attr->rta_len != RTA_LENGTH(FAMILY_ADDRESS_SIZE(family)))
+                                                return -EBADMSG;
+
+                                        m->gateway.family = family;
+                                        memcpy(&m->gateway.address, RTA_DATA(attr), FAMILY_ADDRESS_SIZE(family));
+                                        break;
+                                } else if (attr->rta_type == RTA_VIA) {
+                                        uint16_t gw_family;
+
+                                        if (family != AF_INET)
+                                                return -EINVAL;
+
+                                        if (attr->rta_len < RTA_LENGTH(sizeof(uint16_t)))
+                                                return -EBADMSG;
+
+                                        gw_family = *(uint16_t *) RTA_DATA(attr);
+
+                                        if (gw_family != AF_INET6)
+                                                return -EBADMSG;
+
+                                        if (attr->rta_len != RTA_LENGTH(FAMILY_ADDRESS_SIZE(gw_family) + sizeof(gw_family)))
+                                                return -EBADMSG;
+
+                                        memcpy(&m->gateway, RTA_DATA(attr), FAMILY_ADDRESS_SIZE(gw_family) + sizeof(gw_family));
+                                        break;
+                                }
+                        }
+                }
+
+                r = ordered_set_ensure_put(&set, NULL, m);
+                if (r < 0)
+                        return r;
+
+                TAKE_PTR(m);
+
+                size -= NLMSG_ALIGN(rtnh->rtnh_len);
+                rtnh = RTNH_NEXT(rtnh);
+        }
+
+        if (ret)
+                *ret = TAKE_PTR(set);
+        return 0;
+}
diff --git a/src/libsystemd/sd-netlink/netlink-util.h b/src/libsystemd/sd-netlink/netlink-util.h
new file mode 100644
index 0000000..d28d07a
--- /dev/null
+++ b/src/libsystemd/sd-netlink/netlink-util.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <linux/rtnetlink.h>
+
+#include "sd-netlink.h"
+
+#include "ether-addr-util.h"
+#include "in-addr-util.h"
+#include "ordered-set.h"
+#include "socket-util.h"
+#include "util.h"
+
+/* See struct rtvia in rtnetlink.h */
+typedef struct RouteVia {
+        uint16_t family;
+        union in_addr_union address;
+} _packed_ RouteVia;
+
+typedef struct MultipathRoute {
+        RouteVia gateway;
+        int ifindex;
+        uint32_t weight;
+} MultipathRoute;
+
+int rtnl_message_new_synthetic_error(sd_netlink *rtnl, int error, uint32_t serial, sd_netlink_message **ret);
+uint32_t rtnl_message_get_serial(sd_netlink_message *m);
+void rtnl_message_seal(sd_netlink_message *m);
+
+static inline bool rtnl_message_type_is_neigh(uint16_t type) {
+        return IN_SET(type, RTM_NEWNEIGH, RTM_GETNEIGH, RTM_DELNEIGH);
+}
+
+static inline bool rtnl_message_type_is_route(uint16_t type) {
+        return IN_SET(type, RTM_NEWROUTE, RTM_GETROUTE, RTM_DELROUTE);
+}
+
+static inline bool rtnl_message_type_is_nexthop(uint16_t type) {
+        return IN_SET(type, RTM_NEWNEXTHOP, RTM_GETNEXTHOP, RTM_DELNEXTHOP);
+}
+
+static inline bool rtnl_message_type_is_link(uint16_t type) {
+        return IN_SET(type,
+                      RTM_NEWLINK, RTM_SETLINK, RTM_GETLINK, RTM_DELLINK,
+                      RTM_NEWLINKPROP, RTM_DELLINKPROP, RTM_GETLINKPROP);
+}
+
+static inline bool rtnl_message_type_is_addr(uint16_t type) {
+        return IN_SET(type, RTM_NEWADDR, RTM_GETADDR, RTM_DELADDR);
+}
+
+static inline bool rtnl_message_type_is_addrlabel(uint16_t type) {
+        return IN_SET(type, RTM_NEWADDRLABEL, RTM_DELADDRLABEL, RTM_GETADDRLABEL);
+}
+
+static inline bool rtnl_message_type_is_routing_policy_rule(uint16_t type) {
+        return IN_SET(type, RTM_NEWRULE, RTM_DELRULE, RTM_GETRULE);
+}
+
+static inline bool rtnl_message_type_is_qdisc(uint16_t type) {
+        return IN_SET(type, RTM_NEWQDISC, RTM_DELQDISC, RTM_GETQDISC);
+}
+
+static inline bool rtnl_message_type_is_tclass(uint16_t type) {
+        return IN_SET(type, RTM_NEWTCLASS, RTM_DELTCLASS, RTM_GETTCLASS);
+}
+
+static inline bool rtnl_message_type_is_mdb(uint16_t type) {
+        return IN_SET(type, RTM_NEWMDB, RTM_DELMDB, RTM_GETMDB);
+}
+
+int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name);
+int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias, const struct ether_addr *mac, uint32_t mtu);
+int rtnl_get_link_alternative_names(sd_netlink **rtnl, int ifindex, char ***ret);
+int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names);
+int rtnl_set_link_alternative_names_by_ifname(sd_netlink **rtnl, const char *ifname, char * const *alternative_names);
+int rtnl_delete_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names);
+int rtnl_resolve_link_alternative_name(sd_netlink **rtnl, const char *name);
+int rtnl_get_link_iftype(sd_netlink **rtnl, int ifindex, unsigned short *ret);
+
+int rtnl_log_parse_error(int r);
+int rtnl_log_create_error(int r);
+
+#define netlink_call_async(nl, ret_slot, message, callback, destroy_callback, userdata) \
+        ({                                                              \
+                int (*_callback_)(sd_netlink *, sd_netlink_message *, typeof(userdata)) = callback; \
+                void (*_destroy_)(typeof(userdata)) = destroy_callback; \
+                sd_netlink_call_async(nl, ret_slot, message,            \
+                                      (sd_netlink_message_handler_t) _callback_, \
+                                      (sd_netlink_destroy_t) _destroy_, \
+                                      userdata, 0, __func__);           \
+        })
+
+#define netlink_add_match(nl, ret_slot, match, callback, destroy_callback, userdata, description) \
+        ({                                                              \
+                int (*_callback_)(sd_netlink *, sd_netlink_message *, typeof(userdata)) = callback; \
+                void (*_destroy_)(typeof(userdata)) = destroy_callback; \
+                sd_netlink_add_match(nl, ret_slot, match,               \
+                                     (sd_netlink_message_handler_t) _callback_, \
+                                     (sd_netlink_destroy_t) _destroy_,  \
+                                     userdata, description);            \
+        })
+
+int netlink_message_append_hw_addr(sd_netlink_message *m, unsigned short type, const hw_addr_data *data);
+int netlink_message_append_in_addr_union(sd_netlink_message *m, unsigned short type, int family, const union in_addr_union *data);
+int netlink_message_append_sockaddr_union(sd_netlink_message *m, unsigned short type, const union sockaddr_union *data);
+
+int netlink_message_read_hw_addr(sd_netlink_message *m, unsigned short type, hw_addr_data *data);
+int netlink_message_read_in_addr_union(sd_netlink_message *m, unsigned short type, int family, union in_addr_union *data);
+
+void rtattr_append_attribute_internal(struct rtattr *rta, unsigned short type, const void *data, size_t data_length);
+int rtattr_append_attribute(struct rtattr **rta, unsigned short type, const void *data, size_t data_length);
+
+int rtattr_read_nexthop(const struct rtnexthop *rtnh, size_t size, int family, OrderedSet **ret);
diff --git a/src/libsystemd/sd-netlink/rtnl-message.c b/src/libsystemd/sd-netlink/rtnl-message.c
new file mode 100644
index 0000000..4cabbab
--- /dev/null
+++ b/src/libsystemd/sd-netlink/rtnl-message.c
@@ -0,0 +1,1144 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <netinet/in.h>
+#include <linux/if_addrlabel.h>
+#include <linux/if_bridge.h>
+#include <linux/nexthop.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#include "sd-netlink.h"
+
+#include "format-util.h"
+#include "netlink-internal.h"
+#include "netlink-types.h"
+#include "netlink-util.h"
+#include "socket-util.h"
+#include "util.h"
+
+int sd_rtnl_message_route_set_dst_prefixlen(sd_netlink_message *m, unsigned char prefixlen) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        if ((rtm->rtm_family == AF_INET && prefixlen > 32) ||
+            (rtm->rtm_family == AF_INET6 && prefixlen > 128))
+                return -ERANGE;
+
+        rtm->rtm_dst_len = prefixlen;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_set_src_prefixlen(sd_netlink_message *m, unsigned char prefixlen) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        if ((rtm->rtm_family == AF_INET && prefixlen > 32) ||
+            (rtm->rtm_family == AF_INET6 && prefixlen > 128))
+                return -ERANGE;
+
+        rtm->rtm_src_len = prefixlen;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_set_scope(sd_netlink_message *m, unsigned char scope) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        rtm->rtm_scope = scope;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_set_flags(sd_netlink_message *m, unsigned flags) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        rtm->rtm_flags = flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_flags(const sd_netlink_message *m, unsigned *flags) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(flags, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *flags = rtm->rtm_flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_set_table(sd_netlink_message *m, unsigned char table) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        rtm->rtm_table = table;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_family(const sd_netlink_message *m, int *family) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(family, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *family = rtm->rtm_family;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_set_family(sd_netlink_message *m, int family) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        rtm->rtm_family = family;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_type(const sd_netlink_message *m, unsigned char *type) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(type, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *type = rtm->rtm_type;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_set_type(sd_netlink_message *m, unsigned char type) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        rtm->rtm_type = type;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_protocol(const sd_netlink_message *m, unsigned char *protocol) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(protocol, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *protocol = rtm->rtm_protocol;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_scope(const sd_netlink_message *m, unsigned char *scope) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(scope, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *scope = rtm->rtm_scope;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_tos(const sd_netlink_message *m, unsigned char *tos) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(tos, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *tos = rtm->rtm_tos;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_table(const sd_netlink_message *m, unsigned char *table) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(table, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *table = rtm->rtm_table;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_dst_prefixlen(const sd_netlink_message *m, unsigned char *dst_len) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(dst_len, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *dst_len = rtm->rtm_dst_len;
+
+        return 0;
+}
+
+int sd_rtnl_message_route_get_src_prefixlen(const sd_netlink_message *m, unsigned char *src_len) {
+        struct rtmsg *rtm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_route(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(src_len, -EINVAL);
+
+        rtm = NLMSG_DATA(m->hdr);
+
+        *src_len = rtm->rtm_src_len;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_route(sd_netlink *rtnl, sd_netlink_message **ret,
+                              uint16_t nlmsg_type, int rtm_family,
+                              unsigned char rtm_protocol) {
+        struct rtmsg *rtm;
+        int r;
+
+        assert_return(rtnl_message_type_is_route(nlmsg_type), -EINVAL);
+        assert_return((nlmsg_type == RTM_GETROUTE && rtm_family == AF_UNSPEC) ||
+                      IN_SET(rtm_family, AF_INET, AF_INET6), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWROUTE)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_APPEND;
+
+        rtm = NLMSG_DATA((*ret)->hdr);
+
+        rtm->rtm_family = rtm_family;
+        rtm->rtm_scope = RT_SCOPE_UNIVERSE;
+        rtm->rtm_type = RTN_UNICAST;
+        rtm->rtm_table = RT_TABLE_MAIN;
+        rtm->rtm_protocol = rtm_protocol;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_nexthop(sd_netlink *rtnl, sd_netlink_message **ret,
+                                uint16_t nhmsg_type, int nh_family,
+                                unsigned char nh_protocol) {
+        struct nhmsg *nhm;
+        int r;
+
+        assert_return(rtnl_message_type_is_nexthop(nhmsg_type), -EINVAL);
+        assert_return((nhmsg_type == RTM_GETNEXTHOP && nh_family == AF_UNSPEC) ||
+                      IN_SET(nh_family, AF_INET, AF_INET6), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nhmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nhmsg_type == RTM_NEWNEXTHOP)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_APPEND;
+
+        nhm = NLMSG_DATA((*ret)->hdr);
+
+        nhm->nh_family = nh_family;
+        nhm->nh_scope = RT_SCOPE_UNIVERSE;
+        nhm->nh_protocol = nh_protocol;
+
+        return 0;
+}
+
+int sd_rtnl_message_nexthop_set_flags(sd_netlink_message *m, uint8_t flags) {
+        struct nhmsg *nhm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_nexthop(m->hdr->nlmsg_type), -EINVAL);
+
+        nhm = NLMSG_DATA(m->hdr);
+        nhm->nh_flags |= flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_nexthop_set_family(sd_netlink_message *m, uint8_t family) {
+        struct nhmsg *nhm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+
+        nhm = NLMSG_DATA(m->hdr);
+        nhm->nh_family = family;
+
+        return 0;
+}
+
+int sd_rtnl_message_nexthop_get_family(const sd_netlink_message *m, uint8_t *family) {
+        struct nhmsg *nhm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+
+        nhm = NLMSG_DATA(m->hdr);
+        *family = nhm->nh_family ;
+
+        return 0;
+}
+
+int sd_rtnl_message_neigh_set_flags(sd_netlink_message *m, uint8_t flags) {
+        struct ndmsg *ndm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_neigh(m->hdr->nlmsg_type), -EINVAL);
+
+        ndm = NLMSG_DATA(m->hdr);
+        ndm->ndm_flags |= flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_neigh_set_state(sd_netlink_message *m, uint16_t state) {
+        struct ndmsg *ndm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_neigh(m->hdr->nlmsg_type), -EINVAL);
+
+        ndm = NLMSG_DATA(m->hdr);
+        ndm->ndm_state |= state;
+
+        return 0;
+}
+
+int sd_rtnl_message_neigh_get_flags(const sd_netlink_message *m, uint8_t *flags) {
+        struct ndmsg *ndm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_neigh(m->hdr->nlmsg_type), -EINVAL);
+
+        ndm = NLMSG_DATA(m->hdr);
+        *flags = ndm->ndm_flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_neigh_get_state(const sd_netlink_message *m, uint16_t *state) {
+        struct ndmsg *ndm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_neigh(m->hdr->nlmsg_type), -EINVAL);
+
+        ndm = NLMSG_DATA(m->hdr);
+        *state = ndm->ndm_state;
+
+        return 0;
+}
+
+int sd_rtnl_message_neigh_get_family(const sd_netlink_message *m, int *family) {
+        struct ndmsg *ndm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_neigh(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(family, -EINVAL);
+
+        ndm = NLMSG_DATA(m->hdr);
+
+        *family = ndm->ndm_family;
+
+        return 0;
+}
+
+int sd_rtnl_message_neigh_get_ifindex(const sd_netlink_message *m, int *index) {
+        struct ndmsg *ndm;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_neigh(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(index, -EINVAL);
+
+        ndm = NLMSG_DATA(m->hdr);
+
+        *index = ndm->ndm_ifindex;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_neigh(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t nlmsg_type, int index, int ndm_family) {
+        struct ndmsg *ndm;
+        int r;
+
+        assert_return(rtnl_message_type_is_neigh(nlmsg_type), -EINVAL);
+        assert_return(IN_SET(ndm_family, AF_UNSPEC, AF_INET, AF_INET6, AF_BRIDGE), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWNEIGH)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_APPEND;
+
+        ndm = NLMSG_DATA((*ret)->hdr);
+
+        ndm->ndm_family = ndm_family;
+        ndm->ndm_ifindex = index;
+
+        return 0;
+}
+
+int sd_rtnl_message_link_set_flags(sd_netlink_message *m, unsigned flags, unsigned change) {
+        struct ifinfomsg *ifi;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(change, -EINVAL);
+
+        ifi = NLMSG_DATA(m->hdr);
+
+        ifi->ifi_flags = flags;
+        ifi->ifi_change = change;
+
+        return 0;
+}
+
+int sd_rtnl_message_link_set_type(sd_netlink_message *m, unsigned type) {
+        struct ifinfomsg *ifi;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+
+        ifi = NLMSG_DATA(m->hdr);
+
+        ifi->ifi_type = type;
+
+        return 0;
+}
+
+int sd_rtnl_message_link_set_family(sd_netlink_message *m, unsigned family) {
+        struct ifinfomsg *ifi;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+
+        ifi = NLMSG_DATA(m->hdr);
+
+        ifi->ifi_family = family;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_link(sd_netlink *rtnl, sd_netlink_message **ret,
+                             uint16_t nlmsg_type, int index) {
+        struct ifinfomsg *ifi;
+        int r;
+
+        assert_return(rtnl_message_type_is_link(nlmsg_type), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWLINK)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+        else if (nlmsg_type == RTM_NEWLINKPROP)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL | NLM_F_APPEND;
+
+        ifi = NLMSG_DATA((*ret)->hdr);
+
+        ifi->ifi_family = AF_UNSPEC;
+        ifi->ifi_index = index;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_set_prefixlen(sd_netlink_message *m, unsigned char prefixlen) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        if ((ifa->ifa_family == AF_INET && prefixlen > 32) ||
+            (ifa->ifa_family == AF_INET6 && prefixlen > 128))
+                return -ERANGE;
+
+        ifa->ifa_prefixlen = prefixlen;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_set_flags(sd_netlink_message *m, unsigned char flags) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        ifa->ifa_flags = flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_set_scope(sd_netlink_message *m, unsigned char scope) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        ifa->ifa_scope = scope;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_family(const sd_netlink_message *m, int *family) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(family, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *family = ifa->ifa_family;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_prefixlen(const sd_netlink_message *m, unsigned char *prefixlen) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(prefixlen, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *prefixlen = ifa->ifa_prefixlen;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_scope(const sd_netlink_message *m, unsigned char *scope) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(scope, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *scope = ifa->ifa_scope;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_flags(const sd_netlink_message *m, unsigned char *flags) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(flags, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *flags = ifa->ifa_flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_addr_get_ifindex(const sd_netlink_message *m, int *ifindex) {
+        struct ifaddrmsg *ifa;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addr(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(ifindex, -EINVAL);
+
+        ifa = NLMSG_DATA(m->hdr);
+
+        *ifindex = ifa->ifa_index;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_addr(sd_netlink *rtnl, sd_netlink_message **ret,
+                             uint16_t nlmsg_type, int index,
+                             int family) {
+        struct ifaddrmsg *ifa;
+        int r;
+
+        assert_return(rtnl_message_type_is_addr(nlmsg_type), -EINVAL);
+        assert_return((nlmsg_type == RTM_GETADDR && index == 0) ||
+                      index > 0, -EINVAL);
+        assert_return((nlmsg_type == RTM_GETADDR && family == AF_UNSPEC) ||
+                      IN_SET(family, AF_INET, AF_INET6), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_GETADDR)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_DUMP;
+
+        ifa = NLMSG_DATA((*ret)->hdr);
+
+        ifa->ifa_index = index;
+        ifa->ifa_family = family;
+        if (family == AF_INET)
+                ifa->ifa_prefixlen = 32;
+        else if (family == AF_INET6)
+                ifa->ifa_prefixlen = 128;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_addr_update(sd_netlink *rtnl, sd_netlink_message **ret,
+                             int index, int family) {
+        int r;
+
+        r = sd_rtnl_message_new_addr(rtnl, ret, RTM_NEWADDR, index, family);
+        if (r < 0)
+                return r;
+
+        (*ret)->hdr->nlmsg_flags |= NLM_F_REPLACE;
+
+        return 0;
+}
+
+int sd_rtnl_message_link_get_ifindex(const sd_netlink_message *m, int *ifindex) {
+        struct ifinfomsg *ifi;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(ifindex, -EINVAL);
+
+        ifi = NLMSG_DATA(m->hdr);
+
+        *ifindex = ifi->ifi_index;
+
+        return 0;
+}
+
+int sd_rtnl_message_link_get_flags(const sd_netlink_message *m, unsigned *flags) {
+        struct ifinfomsg *ifi;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(flags, -EINVAL);
+
+        ifi = NLMSG_DATA(m->hdr);
+
+        *flags = ifi->ifi_flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_link_get_type(const sd_netlink_message *m, unsigned short *type) {
+        struct ifinfomsg *ifi;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+        assert_return(type, -EINVAL);
+
+        ifi = NLMSG_DATA(m->hdr);
+
+        *type = ifi->ifi_type;
+
+        return 0;
+}
+
+int sd_rtnl_message_get_family(const sd_netlink_message *m, int *family) {
+        assert_return(m, -EINVAL);
+        assert_return(family, -EINVAL);
+
+        assert(m->hdr);
+
+        if (rtnl_message_type_is_link(m->hdr->nlmsg_type)) {
+                struct ifinfomsg *ifi;
+
+                ifi = NLMSG_DATA(m->hdr);
+
+                *family = ifi->ifi_family;
+
+                return 0;
+        } else if (rtnl_message_type_is_route(m->hdr->nlmsg_type)) {
+                struct rtmsg *rtm;
+
+                rtm = NLMSG_DATA(m->hdr);
+
+                *family = rtm->rtm_family;
+
+                return 0;
+        } else if (rtnl_message_type_is_neigh(m->hdr->nlmsg_type)) {
+                struct ndmsg *ndm;
+
+                ndm = NLMSG_DATA(m->hdr);
+
+                *family = ndm->ndm_family;
+
+                return 0;
+        } else if (rtnl_message_type_is_addr(m->hdr->nlmsg_type)) {
+                struct ifaddrmsg *ifa;
+
+                ifa = NLMSG_DATA(m->hdr);
+
+                *family = ifa->ifa_family;
+
+                return 0;
+        } else if (rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type)) {
+                struct rtmsg *rtm;
+
+                rtm = NLMSG_DATA(m->hdr);
+
+                *family = rtm->rtm_family;
+
+                return 0;
+        } else if (rtnl_message_type_is_nexthop(m->hdr->nlmsg_type)) {
+                struct nhmsg *nhm;
+
+                nhm = NLMSG_DATA(m->hdr);
+
+                *family = nhm->nh_family;
+
+                return 0;
+        }
+
+        return -EOPNOTSUPP;
+}
+
+int sd_rtnl_message_new_addrlabel(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t nlmsg_type, int ifindex, int ifal_family) {
+        struct ifaddrlblmsg *addrlabel;
+        int r;
+
+        assert_return(rtnl_message_type_is_addrlabel(nlmsg_type), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWADDRLABEL)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+
+        addrlabel = NLMSG_DATA((*ret)->hdr);
+
+        addrlabel->ifal_family = ifal_family;
+        addrlabel->ifal_index = ifindex;
+
+        return 0;
+}
+
+int sd_rtnl_message_addrlabel_set_prefixlen(sd_netlink_message *m, unsigned char prefixlen) {
+        struct ifaddrlblmsg *addrlabel;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addrlabel(m->hdr->nlmsg_type), -EINVAL);
+
+        addrlabel = NLMSG_DATA(m->hdr);
+
+        if (prefixlen > 128)
+                return -ERANGE;
+
+        addrlabel->ifal_prefixlen = prefixlen;
+
+        return 0;
+}
+
+int sd_rtnl_message_addrlabel_get_prefixlen(const sd_netlink_message *m, unsigned char *prefixlen) {
+        struct ifaddrlblmsg *addrlabel;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_addrlabel(m->hdr->nlmsg_type), -EINVAL);
+
+        addrlabel = NLMSG_DATA(m->hdr);
+
+        *prefixlen = addrlabel->ifal_prefixlen;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_routing_policy_rule(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t nlmsg_type, int ifal_family) {
+        struct rtmsg *rtm;
+        int r;
+
+        assert_return(rtnl_message_type_is_routing_policy_rule(nlmsg_type), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWRULE)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+
+        rtm = NLMSG_DATA((*ret)->hdr);
+        rtm->rtm_family = ifal_family;
+        rtm->rtm_protocol = RTPROT_BOOT;
+        rtm->rtm_scope = RT_SCOPE_UNIVERSE;
+        rtm->rtm_type = RTN_UNICAST;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_set_tos(sd_netlink_message *m, unsigned char tos) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        routing_policy_rule->rtm_tos = tos;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_get_tos(const sd_netlink_message *m, unsigned char *tos) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        *tos = routing_policy_rule->rtm_tos;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_set_table(sd_netlink_message *m, unsigned char table) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        routing_policy_rule->rtm_table = table;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_get_table(const sd_netlink_message *m, unsigned char *table) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        *table = routing_policy_rule->rtm_table;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_set_flags(sd_netlink_message *m, unsigned flags) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+        routing_policy_rule->rtm_flags |= flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_get_flags(const sd_netlink_message *m, unsigned *flags) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+        *flags = routing_policy_rule->rtm_flags;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_set_rtm_type(sd_netlink_message *m, unsigned char type) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        routing_policy_rule->rtm_type = type;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_get_rtm_type(const sd_netlink_message *m, unsigned char *type) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        *type =  routing_policy_rule->rtm_type;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_set_rtm_dst_prefixlen(sd_netlink_message *m, unsigned char len) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        routing_policy_rule->rtm_dst_len = len;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_get_rtm_dst_prefixlen(const sd_netlink_message *m, unsigned char *len) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        *len = routing_policy_rule->rtm_dst_len;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_set_rtm_src_prefixlen(sd_netlink_message *m, unsigned char len) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        routing_policy_rule->rtm_src_len = len;
+
+        return 0;
+}
+
+int sd_rtnl_message_routing_policy_rule_get_rtm_src_prefixlen(const sd_netlink_message *m, unsigned char *len) {
+        struct rtmsg *routing_policy_rule;
+
+        assert_return(m, -EINVAL);
+        assert_return(m->hdr, -EINVAL);
+        assert_return(rtnl_message_type_is_routing_policy_rule(m->hdr->nlmsg_type), -EINVAL);
+
+        routing_policy_rule = NLMSG_DATA(m->hdr);
+
+        *len = routing_policy_rule->rtm_src_len;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_qdisc(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t nlmsg_type, int tcm_family, int tcm_ifindex) {
+        struct tcmsg *tcm;
+        int r;
+
+        assert_return(rtnl_message_type_is_qdisc(nlmsg_type), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWQDISC)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+
+        tcm = NLMSG_DATA((*ret)->hdr);
+        tcm->tcm_family = tcm_family;
+        tcm->tcm_ifindex = tcm_ifindex;
+
+        return 0;
+}
+
+int sd_rtnl_message_set_qdisc_parent(sd_netlink_message *m, uint32_t parent) {
+        struct tcmsg *tcm;
+
+        assert_return(rtnl_message_type_is_qdisc(m->hdr->nlmsg_type), -EINVAL);
+
+        tcm = NLMSG_DATA(m->hdr);
+        tcm->tcm_parent = parent;
+
+        return 0;
+}
+
+int sd_rtnl_message_set_qdisc_handle(sd_netlink_message *m, uint32_t handle) {
+        struct tcmsg *tcm;
+
+        assert_return(rtnl_message_type_is_qdisc(m->hdr->nlmsg_type), -EINVAL);
+
+        tcm = NLMSG_DATA(m->hdr);
+        tcm->tcm_handle = handle;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_tclass(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t nlmsg_type, int tcm_family, int tcm_ifindex) {
+        struct tcmsg *tcm;
+        int r;
+
+        assert_return(rtnl_message_type_is_tclass(nlmsg_type), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWTCLASS)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+
+        tcm = NLMSG_DATA((*ret)->hdr);
+        tcm->tcm_family = tcm_family;
+        tcm->tcm_ifindex = tcm_ifindex;
+
+        return 0;
+}
+
+int sd_rtnl_message_set_tclass_parent(sd_netlink_message *m, uint32_t parent) {
+        struct tcmsg *tcm;
+
+        assert_return(rtnl_message_type_is_tclass(m->hdr->nlmsg_type), -EINVAL);
+
+        tcm = NLMSG_DATA(m->hdr);
+        tcm->tcm_parent = parent;
+
+        return 0;
+}
+
+int sd_rtnl_message_set_tclass_handle(sd_netlink_message *m, uint32_t handle) {
+        struct tcmsg *tcm;
+
+        assert_return(rtnl_message_type_is_tclass(m->hdr->nlmsg_type), -EINVAL);
+
+        tcm = NLMSG_DATA(m->hdr);
+        tcm->tcm_handle = handle;
+
+        return 0;
+}
+
+int sd_rtnl_message_new_mdb(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t nlmsg_type, int mdb_ifindex) {
+        struct br_port_msg *bpm;
+        int r;
+
+        assert_return(rtnl_message_type_is_mdb(nlmsg_type), -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        r = message_new(rtnl, ret, nlmsg_type);
+        if (r < 0)
+                return r;
+
+        if (nlmsg_type == RTM_NEWMDB)
+                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_EXCL;
+
+        bpm = NLMSG_DATA((*ret)->hdr);
+        bpm->family = AF_BRIDGE;
+        bpm->ifindex = mdb_ifindex;
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-netlink/sd-netlink.c b/src/libsystemd/sd-netlink/sd-netlink.c
new file mode 100644
index 0000000..7801101
--- /dev/null
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -0,0 +1,921 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <poll.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "hashmap.h"
+#include "io-util.h"
+#include "macro.h"
+#include "netlink-internal.h"
+#include "netlink-slot.h"
+#include "netlink-util.h"
+#include "process-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "util.h"
+
+static int sd_netlink_new(sd_netlink **ret) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        rtnl = new(sd_netlink, 1);
+        if (!rtnl)
+                return -ENOMEM;
+
+        *rtnl = (sd_netlink) {
+                .n_ref = 1,
+                .fd = -1,
+                .sockaddr.nl.nl_family = AF_NETLINK,
+                .original_pid = getpid_cached(),
+                .protocol = -1,
+
+                /* Change notification responses have sequence 0, so we must
+                 * start our request sequence numbers at 1, or we may confuse our
+                 * responses with notifications from the kernel */
+                .serial = 1,
+
+        };
+
+        /* We guarantee that the read buffer has at least space for
+         * a message header */
+        if (!greedy_realloc((void**)&rtnl->rbuffer, &rtnl->rbuffer_allocated,
+                            sizeof(struct nlmsghdr), sizeof(uint8_t)))
+                return -ENOMEM;
+
+        *ret = TAKE_PTR(rtnl);
+
+        return 0;
+}
+
+int sd_netlink_new_from_netlink(sd_netlink **ret, int fd) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        socklen_t addrlen;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_netlink_new(&rtnl);
+        if (r < 0)
+                return r;
+
+        addrlen = sizeof(rtnl->sockaddr);
+
+        r = getsockname(fd, &rtnl->sockaddr.sa, &addrlen);
+        if (r < 0)
+                return -errno;
+
+        if (rtnl->sockaddr.nl.nl_family != AF_NETLINK)
+                return -EINVAL;
+
+        rtnl->fd = fd;
+
+        *ret = TAKE_PTR(rtnl);
+
+        return 0;
+}
+
+static bool rtnl_pid_changed(const sd_netlink *rtnl) {
+        assert(rtnl);
+
+        /* We don't support people creating an rtnl connection and
+         * keeping it around over a fork(). Let's complain. */
+
+        return rtnl->original_pid != getpid_cached();
+}
+
+int sd_netlink_open_fd(sd_netlink **ret, int fd) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        int r;
+        int protocol;
+        socklen_t l;
+
+        assert_return(ret, -EINVAL);
+        assert_return(fd >= 0, -EBADF);
+
+        r = sd_netlink_new(&rtnl);
+        if (r < 0)
+                return r;
+
+        l = sizeof(protocol);
+        r = getsockopt(fd, SOL_SOCKET, SO_PROTOCOL, &protocol, &l);
+        if (r < 0)
+                return r;
+
+        rtnl->fd = fd;
+        rtnl->protocol = protocol;
+
+        r = setsockopt_int(fd, SOL_NETLINK, NETLINK_EXT_ACK, 1);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: Failed to enable NETLINK_EXT_ACK option, ignoring: %m");
+
+        r = socket_bind(rtnl);
+        if (r < 0) {
+                rtnl->fd = -1; /* on failure, the caller remains owner of the fd, hence don't close it here */
+                rtnl->protocol = -1;
+                return r;
+        }
+
+        *ret = TAKE_PTR(rtnl);
+
+        return 0;
+}
+
+int netlink_open_family(sd_netlink **ret, int family) {
+        _cleanup_close_ int fd = -1;
+        int r;
+
+        fd = socket_open(family);
+        if (fd < 0)
+                return fd;
+
+        r = sd_netlink_open_fd(ret, fd);
+        if (r < 0)
+                return r;
+        TAKE_FD(fd);
+
+        return 0;
+}
+
+int sd_netlink_open(sd_netlink **ret) {
+        return netlink_open_family(ret, NETLINK_ROUTE);
+}
+
+int sd_netlink_inc_rcvbuf(sd_netlink *rtnl, size_t size) {
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        return fd_inc_rcvbuf(rtnl->fd, size);
+}
+
+static sd_netlink *netlink_free(sd_netlink *rtnl) {
+        sd_netlink_slot *s;
+        unsigned i;
+
+        assert(rtnl);
+
+        for (i = 0; i < rtnl->rqueue_size; i++)
+                sd_netlink_message_unref(rtnl->rqueue[i]);
+        free(rtnl->rqueue);
+
+        for (i = 0; i < rtnl->rqueue_partial_size; i++)
+                sd_netlink_message_unref(rtnl->rqueue_partial[i]);
+        free(rtnl->rqueue_partial);
+
+        free(rtnl->rbuffer);
+
+        while ((s = rtnl->slots)) {
+                assert(s->floating);
+                netlink_slot_disconnect(s, true);
+        }
+        hashmap_free(rtnl->reply_callbacks);
+        prioq_free(rtnl->reply_callbacks_prioq);
+
+        sd_event_source_unref(rtnl->io_event_source);
+        sd_event_source_unref(rtnl->time_event_source);
+        sd_event_unref(rtnl->event);
+
+        hashmap_free(rtnl->broadcast_group_refs);
+
+        hashmap_free(rtnl->genl_family_to_nlmsg_type);
+        hashmap_free(rtnl->nlmsg_type_to_genl_family);
+
+        safe_close(rtnl->fd);
+        return mfree(rtnl);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_netlink, sd_netlink, netlink_free);
+
+static void rtnl_seal_message(sd_netlink *rtnl, sd_netlink_message *m) {
+        assert(rtnl);
+        assert(!rtnl_pid_changed(rtnl));
+        assert(m);
+        assert(m->hdr);
+
+        /* don't use seq == 0, as that is used for broadcasts, so we
+           would get confused by replies to such messages */
+        m->hdr->nlmsg_seq = rtnl->serial++ ? : rtnl->serial++;
+
+        rtnl_message_seal(m);
+
+        return;
+}
+
+int sd_netlink_send(sd_netlink *nl,
+                    sd_netlink_message *message,
+                    uint32_t *serial) {
+        int r;
+
+        assert_return(nl, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+        assert_return(message, -EINVAL);
+        assert_return(!message->sealed, -EPERM);
+
+        rtnl_seal_message(nl, message);
+
+        r = socket_write_message(nl, message);
+        if (r < 0)
+                return r;
+
+        if (serial)
+                *serial = rtnl_message_get_serial(message);
+
+        return 1;
+}
+
+int rtnl_rqueue_make_room(sd_netlink *rtnl) {
+        assert(rtnl);
+
+        if (rtnl->rqueue_size >= RTNL_RQUEUE_MAX)
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOBUFS),
+                                       "rtnl: exhausted the read queue size (%d)",
+                                       RTNL_RQUEUE_MAX);
+
+        if (!GREEDY_REALLOC(rtnl->rqueue, rtnl->rqueue_allocated, rtnl->rqueue_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+int rtnl_rqueue_partial_make_room(sd_netlink *rtnl) {
+        assert(rtnl);
+
+        if (rtnl->rqueue_partial_size >= RTNL_RQUEUE_MAX)
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOBUFS),
+                                       "rtnl: exhausted the partial read queue size (%d)",
+                                       RTNL_RQUEUE_MAX);
+
+        if (!GREEDY_REALLOC(rtnl->rqueue_partial, rtnl->rqueue_partial_allocated,
+                            rtnl->rqueue_partial_size + 1))
+                return -ENOMEM;
+
+        return 0;
+}
+
+static int dispatch_rqueue(sd_netlink *rtnl, sd_netlink_message **message) {
+        int r;
+
+        assert(rtnl);
+        assert(message);
+
+        if (rtnl->rqueue_size <= 0) {
+                /* Try to read a new message */
+                r = socket_read_message(rtnl);
+                if (r == -ENOBUFS) { /* FIXME: ignore buffer overruns for now */
+                        log_debug_errno(r, "Got ENOBUFS from netlink socket, ignoring.");
+                        return 1;
+                }
+                if (r <= 0)
+                        return r;
+        }
+
+        /* Dispatch a queued message */
+        *message = rtnl->rqueue[0];
+        rtnl->rqueue_size--;
+        memmove(rtnl->rqueue, rtnl->rqueue + 1, sizeof(sd_netlink_message*) * rtnl->rqueue_size);
+
+        return 1;
+}
+
+static int process_timeout(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        struct reply_callback *c;
+        sd_netlink_slot *slot;
+        usec_t n;
+        int r;
+
+        assert(rtnl);
+
+        c = prioq_peek(rtnl->reply_callbacks_prioq);
+        if (!c)
+                return 0;
+
+        n = now(CLOCK_MONOTONIC);
+        if (c->timeout > n)
+                return 0;
+
+        r = rtnl_message_new_synthetic_error(rtnl, -ETIMEDOUT, c->serial, &m);
+        if (r < 0)
+                return r;
+
+        assert_se(prioq_pop(rtnl->reply_callbacks_prioq) == c);
+        c->timeout = 0;
+        hashmap_remove(rtnl->reply_callbacks, &c->serial);
+
+        slot = container_of(c, sd_netlink_slot, reply_callback);
+
+        r = c->callback(rtnl, m, slot->userdata);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: timedout callback %s%s%sfailed: %m",
+                                slot->description ? "'" : "",
+                                strempty(slot->description),
+                                slot->description ? "' " : "");
+
+        if (slot->floating)
+                netlink_slot_disconnect(slot, true);
+
+        return 1;
+}
+
+static int process_reply(sd_netlink *rtnl, sd_netlink_message *m) {
+        struct reply_callback *c;
+        sd_netlink_slot *slot;
+        uint64_t serial;
+        uint16_t type;
+        int r;
+
+        assert(rtnl);
+        assert(m);
+
+        serial = rtnl_message_get_serial(m);
+        c = hashmap_remove(rtnl->reply_callbacks, &serial);
+        if (!c)
+                return 0;
+
+        if (c->timeout != 0) {
+                prioq_remove(rtnl->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout = 0;
+        }
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return r;
+
+        if (type == NLMSG_DONE)
+                m = NULL;
+
+        slot = container_of(c, sd_netlink_slot, reply_callback);
+
+        r = c->callback(rtnl, m, slot->userdata);
+        if (r < 0)
+                log_debug_errno(r, "sd-netlink: reply callback %s%s%sfailed: %m",
+                                slot->description ? "'" : "",
+                                strempty(slot->description),
+                                slot->description ? "' " : "");
+
+        if (slot->floating)
+                netlink_slot_disconnect(slot, true);
+
+        return 1;
+}
+
+static int process_match(sd_netlink *rtnl, sd_netlink_message *m) {
+        struct match_callback *c;
+        sd_netlink_slot *slot;
+        uint16_t type;
+        int r;
+
+        assert(rtnl);
+        assert(m);
+
+        r = sd_netlink_message_get_type(m, &type);
+        if (r < 0)
+                return r;
+
+        LIST_FOREACH(match_callbacks, c, rtnl->match_callbacks) {
+                if (type == c->type) {
+                        slot = container_of(c, sd_netlink_slot, match_callback);
+
+                        r = c->callback(rtnl, m, slot->userdata);
+                        if (r != 0) {
+                                if (r < 0)
+                                        log_debug_errno(r, "sd-netlink: match callback %s%s%sfailed: %m",
+                                                        slot->description ? "'" : "",
+                                                        strempty(slot->description),
+                                                        slot->description ? "' " : "");
+
+                                break;
+                        }
+                }
+        }
+
+        return 1;
+}
+
+static int process_running(sd_netlink *rtnl, sd_netlink_message **ret) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        int r;
+
+        assert(rtnl);
+
+        r = process_timeout(rtnl);
+        if (r != 0)
+                goto null_message;
+
+        r = dispatch_rqueue(rtnl, &m);
+        if (r < 0)
+                return r;
+        if (!m)
+                goto null_message;
+
+        if (sd_netlink_message_is_broadcast(m)) {
+                r = process_match(rtnl, m);
+                if (r != 0)
+                        goto null_message;
+        } else {
+                r = process_reply(rtnl, m);
+                if (r != 0)
+                        goto null_message;
+        }
+
+        if (ret) {
+                *ret = TAKE_PTR(m);
+
+                return 1;
+        }
+
+        return 1;
+
+null_message:
+        if (r >= 0 && ret)
+                *ret = NULL;
+
+        return r;
+}
+
+int sd_netlink_process(sd_netlink *rtnl, sd_netlink_message **ret) {
+        NETLINK_DONT_DESTROY(rtnl);
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+        assert_return(!rtnl->processing, -EBUSY);
+
+        rtnl->processing = true;
+        r = process_running(rtnl, ret);
+        rtnl->processing = false;
+
+        return r;
+}
+
+static usec_t calc_elapse(uint64_t usec) {
+        if (usec == (uint64_t) -1)
+                return 0;
+
+        if (usec == 0)
+                usec = RTNL_DEFAULT_TIMEOUT;
+
+        return now(CLOCK_MONOTONIC) + usec;
+}
+
+static int rtnl_poll(sd_netlink *rtnl, bool need_more, uint64_t timeout_usec) {
+        usec_t m = USEC_INFINITY;
+        int r, e;
+
+        assert(rtnl);
+
+        e = sd_netlink_get_events(rtnl);
+        if (e < 0)
+                return e;
+
+        if (need_more)
+                /* Caller wants more data, and doesn't care about
+                 * what's been read or any other timeouts. */
+                e |= POLLIN;
+        else {
+                usec_t until;
+                /* Caller wants to process if there is something to
+                 * process, but doesn't care otherwise */
+
+                r = sd_netlink_get_timeout(rtnl, &until);
+                if (r < 0)
+                        return r;
+                if (r > 0) {
+                        usec_t nw;
+                        nw = now(CLOCK_MONOTONIC);
+                        m = until > nw ? until - nw : 0;
+                }
+        }
+
+        if (timeout_usec != (uint64_t) -1 && (m == USEC_INFINITY || timeout_usec < m))
+                m = timeout_usec;
+
+        r = fd_wait_for_event(rtnl->fd, e, m);
+        if (r <= 0)
+                return r;
+
+        return 1;
+}
+
+int sd_netlink_wait(sd_netlink *nl, uint64_t timeout_usec) {
+        assert_return(nl, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+
+        if (nl->rqueue_size > 0)
+                return 0;
+
+        return rtnl_poll(nl, false, timeout_usec);
+}
+
+static int timeout_compare(const void *a, const void *b) {
+        const struct reply_callback *x = a, *y = b;
+
+        if (x->timeout != 0 && y->timeout == 0)
+                return -1;
+
+        if (x->timeout == 0 && y->timeout != 0)
+                return 1;
+
+        return CMP(x->timeout, y->timeout);
+}
+
+int sd_netlink_call_async(
+                sd_netlink *nl,
+                sd_netlink_slot **ret_slot,
+                sd_netlink_message *m,
+                sd_netlink_message_handler_t callback,
+                sd_netlink_destroy_t destroy_callback,
+                void *userdata,
+                uint64_t usec,
+                const char *description) {
+        _cleanup_free_ sd_netlink_slot *slot = NULL;
+        uint32_t s;
+        int r, k;
+
+        assert_return(nl, -EINVAL);
+        assert_return(m, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!rtnl_pid_changed(nl), -ECHILD);
+
+        r = hashmap_ensure_allocated(&nl->reply_callbacks, &uint64_hash_ops);
+        if (r < 0)
+                return r;
+
+        if (usec != (uint64_t) -1) {
+                r = prioq_ensure_allocated(&nl->reply_callbacks_prioq, timeout_compare);
+                if (r < 0)
+                        return r;
+        }
+
+        r = netlink_slot_allocate(nl, !ret_slot, NETLINK_REPLY_CALLBACK, sizeof(struct reply_callback), userdata, description, &slot);
+        if (r < 0)
+                return r;
+
+        slot->reply_callback.callback = callback;
+        slot->reply_callback.timeout = calc_elapse(usec);
+
+        k = sd_netlink_send(nl, m, &s);
+        if (k < 0)
+                return k;
+
+        slot->reply_callback.serial = s;
+
+        r = hashmap_put(nl->reply_callbacks, &slot->reply_callback.serial, &slot->reply_callback);
+        if (r < 0)
+                return r;
+
+        if (slot->reply_callback.timeout != 0) {
+                r = prioq_put(nl->reply_callbacks_prioq, &slot->reply_callback, &slot->reply_callback.prioq_idx);
+                if (r < 0) {
+                        (void) hashmap_remove(nl->reply_callbacks, &slot->reply_callback.serial);
+                        return r;
+                }
+        }
+
+        /* Set this at last. Otherwise, some failures in above call the destroy callback but some do not. */
+        slot->destroy_callback = destroy_callback;
+
+        if (ret_slot)
+                *ret_slot = slot;
+
+        TAKE_PTR(slot);
+
+        return k;
+}
+
+int sd_netlink_call(sd_netlink *rtnl,
+                sd_netlink_message *message,
+                uint64_t usec,
+                sd_netlink_message **ret) {
+        usec_t timeout;
+        uint32_t serial;
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+        assert_return(message, -EINVAL);
+
+        r = sd_netlink_send(rtnl, message, &serial);
+        if (r < 0)
+                return r;
+
+        timeout = calc_elapse(usec);
+
+        for (;;) {
+                usec_t left;
+                unsigned i;
+
+                for (i = 0; i < rtnl->rqueue_size; i++) {
+                        uint32_t received_serial;
+
+                        received_serial = rtnl_message_get_serial(rtnl->rqueue[i]);
+
+                        if (received_serial == serial) {
+                                _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *incoming = NULL;
+                                uint16_t type;
+
+                                incoming = rtnl->rqueue[i];
+
+                                /* found a match, remove from rqueue and return it */
+                                memmove(rtnl->rqueue + i,rtnl->rqueue + i + 1,
+                                        sizeof(sd_netlink_message*) * (rtnl->rqueue_size - i - 1));
+                                rtnl->rqueue_size--;
+
+                                r = sd_netlink_message_get_errno(incoming);
+                                if (r < 0)
+                                        return r;
+
+                                r = sd_netlink_message_get_type(incoming, &type);
+                                if (r < 0)
+                                        return r;
+
+                                if (type == NLMSG_DONE) {
+                                        *ret = NULL;
+                                        return 0;
+                                }
+
+                                if (ret)
+                                        *ret = TAKE_PTR(incoming);
+
+                                return 1;
+                        }
+                }
+
+                r = socket_read_message(rtnl);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        /* received message, so try to process straight away */
+                        continue;
+
+                if (timeout > 0) {
+                        usec_t n;
+
+                        n = now(CLOCK_MONOTONIC);
+                        if (n >= timeout)
+                                return -ETIMEDOUT;
+
+                        left = timeout - n;
+                } else
+                        left = (uint64_t) -1;
+
+                r = rtnl_poll(rtnl, true, left);
+                if (r < 0)
+                        return r;
+                else if (r == 0)
+                        return -ETIMEDOUT;
+        }
+}
+
+int sd_netlink_get_events(const sd_netlink *rtnl) {
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        if (rtnl->rqueue_size == 0)
+                return POLLIN;
+        else
+                return 0;
+}
+
+int sd_netlink_get_timeout(const sd_netlink *rtnl, uint64_t *timeout_usec) {
+        struct reply_callback *c;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(timeout_usec, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        if (rtnl->rqueue_size > 0) {
+                *timeout_usec = 0;
+                return 1;
+        }
+
+        c = prioq_peek(rtnl->reply_callbacks_prioq);
+        if (!c) {
+                *timeout_usec = (uint64_t) -1;
+                return 0;
+        }
+
+        *timeout_usec = c->timeout;
+
+        return 1;
+}
+
+static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_netlink *rtnl = userdata;
+        int r;
+
+        assert(rtnl);
+
+        r = sd_netlink_process(rtnl, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_netlink *rtnl = userdata;
+        int r;
+
+        assert(rtnl);
+
+        r = sd_netlink_process(rtnl, NULL);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int prepare_callback(sd_event_source *s, void *userdata) {
+        sd_netlink *rtnl = userdata;
+        int r, e;
+        usec_t until;
+
+        assert(s);
+        assert(rtnl);
+
+        e = sd_netlink_get_events(rtnl);
+        if (e < 0)
+                return e;
+
+        r = sd_event_source_set_io_events(rtnl->io_event_source, e);
+        if (r < 0)
+                return r;
+
+        r = sd_netlink_get_timeout(rtnl, &until);
+        if (r < 0)
+                return r;
+        if (r > 0) {
+                int j;
+
+                j = sd_event_source_set_time(rtnl->time_event_source, until);
+                if (j < 0)
+                        return j;
+        }
+
+        r = sd_event_source_set_enabled(rtnl->time_event_source, r > 0);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+int sd_netlink_attach_event(sd_netlink *rtnl, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(!rtnl->event, -EBUSY);
+
+        assert(!rtnl->io_event_source);
+        assert(!rtnl->time_event_source);
+
+        if (event)
+                rtnl->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&rtnl->event);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_event_add_io(rtnl->event, &rtnl->io_event_source, rtnl->fd, 0, io_callback, rtnl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(rtnl->io_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(rtnl->io_event_source, "rtnl-receive-message");
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_prepare(rtnl->io_event_source, prepare_callback);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_add_time(rtnl->event, &rtnl->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, rtnl);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(rtnl->time_event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_description(rtnl->time_event_source, "rtnl-timer");
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        sd_netlink_detach_event(rtnl);
+        return r;
+}
+
+int sd_netlink_detach_event(sd_netlink *rtnl) {
+        assert_return(rtnl, -EINVAL);
+        assert_return(rtnl->event, -ENXIO);
+
+        rtnl->io_event_source = sd_event_source_unref(rtnl->io_event_source);
+
+        rtnl->time_event_source = sd_event_source_unref(rtnl->time_event_source);
+
+        rtnl->event = sd_event_unref(rtnl->event);
+
+        return 0;
+}
+
+int sd_netlink_add_match(
+                sd_netlink *rtnl,
+                sd_netlink_slot **ret_slot,
+                uint16_t type,
+                sd_netlink_message_handler_t callback,
+                sd_netlink_destroy_t destroy_callback,
+                void *userdata,
+                const char *description) {
+        _cleanup_free_ sd_netlink_slot *slot = NULL;
+        int r;
+
+        assert_return(rtnl, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!rtnl_pid_changed(rtnl), -ECHILD);
+
+        r = netlink_slot_allocate(rtnl, !ret_slot, NETLINK_MATCH_CALLBACK, sizeof(struct match_callback), userdata, description, &slot);
+        if (r < 0)
+                return r;
+
+        slot->match_callback.callback = callback;
+        slot->match_callback.type = type;
+
+        switch (type) {
+                case RTM_NEWLINK:
+                case RTM_DELLINK:
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_LINK);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                case RTM_NEWADDR:
+                case RTM_DELADDR:
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV4_IFADDR);
+                        if (r < 0)
+                                return r;
+
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV6_IFADDR);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                case RTM_NEWNEIGH:
+                case RTM_DELNEIGH:
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_NEIGH);
+                        if (r < 0)
+                                return r;
+
+                        break;
+                case RTM_NEWROUTE:
+                case RTM_DELROUTE:
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV4_ROUTE);
+                        if (r < 0)
+                                return r;
+
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV6_ROUTE);
+                        if (r < 0)
+                                return r;
+                        break;
+                case RTM_NEWRULE:
+                case RTM_DELRULE:
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV4_RULE);
+                        if (r < 0)
+                                return r;
+
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_IPV6_RULE);
+                        if (r < 0)
+                                return r;
+                        break;
+                case RTM_NEWNEXTHOP:
+                case RTM_DELNEXTHOP:
+                        r = socket_broadcast_group_ref(rtnl, RTNLGRP_NEXTHOP);
+                        if (r < 0)
+                                return r;
+                break;
+
+                default:
+                        return -EOPNOTSUPP;
+        }
+
+        LIST_PREPEND(match_callbacks, rtnl->match_callbacks, &slot->match_callback);
+
+        /* Set this at last. Otherwise, some failures in above call the destroy callback but some do not. */
+        slot->destroy_callback = destroy_callback;
+
+        if (ret_slot)
+                *ret_slot = slot;
+
+        TAKE_PTR(slot);
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-netlink/test-netlink.c b/src/libsystemd/sd-netlink/test-netlink.c
new file mode 100644
index 0000000..41787c5
--- /dev/null
+++ b/src/libsystemd/sd-netlink/test-netlink.c
@@ -0,0 +1,642 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <net/if.h>
+#include <netinet/ether.h>
+#include <linux/genetlink.h>
+
+#include "sd-netlink.h"
+
+#include "alloc-util.h"
+#include "ether-addr-util.h"
+#include "macro.h"
+#include "netlink-util.h"
+#include "socket-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
+
+static void test_message_link_bridge(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
+        uint32_t cost;
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &message, RTM_NEWLINK, 1) >= 0);
+        assert_se(sd_rtnl_message_link_set_family(message, AF_BRIDGE) >= 0);
+        assert_se(sd_netlink_message_open_container(message, IFLA_PROTINFO) >= 0);
+        assert_se(sd_netlink_message_append_u32(message, IFLA_BRPORT_COST, 10) >= 0);
+        assert_se(sd_netlink_message_close_container(message) >= 0);
+
+        assert_se(sd_netlink_message_rewind(message, NULL) >= 0);
+
+        assert_se(sd_netlink_message_enter_container(message, IFLA_PROTINFO) >= 0);
+        assert_se(sd_netlink_message_read_u32(message, IFLA_BRPORT_COST, &cost) >= 0);
+        assert_se(cost == 10);
+        assert_se(sd_netlink_message_exit_container(message) >= 0);
+}
+
+static void test_link_configure(sd_netlink *rtnl, int ifindex) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
+        const char *mac = "98:fe:94:3f:c6:18", *name = "test";
+        char buffer[ETHER_ADDR_TO_STRING_MAX];
+        uint32_t mtu = 1450, mtu_out;
+        const char *name_out;
+        struct ether_addr mac_out;
+
+        /* we'd really like to test NEWLINK, but let's not mess with the running kernel */
+        assert_se(sd_rtnl_message_new_link(rtnl, &message, RTM_GETLINK, ifindex) >= 0);
+        assert_se(sd_netlink_message_append_string(message, IFLA_IFNAME, name) >= 0);
+        assert_se(sd_netlink_message_append_ether_addr(message, IFLA_ADDRESS, ether_aton(mac)) >= 0);
+        assert_se(sd_netlink_message_append_u32(message, IFLA_MTU, mtu) >= 0);
+
+        assert_se(sd_netlink_call(rtnl, message, 0, NULL) == 1);
+        assert_se(sd_netlink_message_rewind(message, NULL) >= 0);
+
+        assert_se(sd_netlink_message_read_string(message, IFLA_IFNAME, &name_out) >= 0);
+        assert_se(streq(name, name_out));
+
+        assert_se(sd_netlink_message_read_ether_addr(message, IFLA_ADDRESS, &mac_out) >= 0);
+        assert_se(streq(mac, ether_addr_to_string(&mac_out, buffer)));
+
+        assert_se(sd_netlink_message_read_u32(message, IFLA_MTU, &mtu_out) >= 0);
+        assert_se(mtu == mtu_out);
+}
+
+static void test_link_get(sd_netlink *rtnl, int ifindex) {
+        sd_netlink_message *m;
+        sd_netlink_message *r;
+        uint32_t mtu = 1500;
+        const char *str_data;
+        uint8_t u8_data;
+        uint32_t u32_data;
+        struct ether_addr eth_data;
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+        assert_se(m);
+
+        /* u8 test cases  */
+        assert_se(sd_netlink_message_append_u8(m, IFLA_CARRIER, 0) >= 0);
+        assert_se(sd_netlink_message_append_u8(m, IFLA_OPERSTATE, 0) >= 0);
+        assert_se(sd_netlink_message_append_u8(m, IFLA_LINKMODE, 0) >= 0);
+
+        /* u32 test cases */
+        assert_se(sd_netlink_message_append_u32(m, IFLA_MTU, mtu) >= 0);
+        assert_se(sd_netlink_message_append_u32(m, IFLA_GROUP, 0) >= 0);
+        assert_se(sd_netlink_message_append_u32(m, IFLA_TXQLEN, 0) >= 0);
+        assert_se(sd_netlink_message_append_u32(m, IFLA_NUM_TX_QUEUES, 0) >= 0);
+        assert_se(sd_netlink_message_append_u32(m, IFLA_NUM_RX_QUEUES, 0) >= 0);
+
+        assert_se(sd_netlink_call(rtnl, m, -1, &r) == 1);
+
+        assert_se(sd_netlink_message_read_string(r, IFLA_IFNAME, &str_data) == 0);
+
+        assert_se(sd_netlink_message_read_u8(r, IFLA_CARRIER, &u8_data) == 0);
+        assert_se(sd_netlink_message_read_u8(r, IFLA_OPERSTATE, &u8_data) == 0);
+        assert_se(sd_netlink_message_read_u8(r, IFLA_LINKMODE, &u8_data) == 0);
+
+        assert_se(sd_netlink_message_read_u32(r, IFLA_MTU, &u32_data) == 0);
+        assert_se(sd_netlink_message_read_u32(r, IFLA_GROUP, &u32_data) == 0);
+        assert_se(sd_netlink_message_read_u32(r, IFLA_TXQLEN, &u32_data) == 0);
+        assert_se(sd_netlink_message_read_u32(r, IFLA_NUM_TX_QUEUES, &u32_data) == 0);
+        assert_se(sd_netlink_message_read_u32(r, IFLA_NUM_RX_QUEUES, &u32_data) == 0);
+
+        assert_se(sd_netlink_message_read_ether_addr(r, IFLA_ADDRESS, &eth_data) == 0);
+
+        assert_se((m = sd_netlink_message_unref(m)) == NULL);
+        assert_se((r = sd_netlink_message_unref(r)) == NULL);
+}
+
+static void test_address_get(sd_netlink *rtnl, int ifindex) {
+        sd_netlink_message *m;
+        sd_netlink_message *r;
+        struct in_addr in_data;
+        struct ifa_cacheinfo cache;
+        const char *label;
+
+        assert_se(sd_rtnl_message_new_addr(rtnl, &m, RTM_GETADDR, ifindex, AF_INET) >= 0);
+        assert_se(m);
+
+        assert_se(sd_netlink_call(rtnl, m, -1, &r) == 1);
+
+        assert_se(sd_netlink_message_read_in_addr(r, IFA_LOCAL, &in_data) == 0);
+        assert_se(sd_netlink_message_read_in_addr(r, IFA_ADDRESS, &in_data) == 0);
+        assert_se(sd_netlink_message_read_string(r, IFA_LABEL, &label) == 0);
+        assert_se(sd_netlink_message_read_cache_info(r, IFA_CACHEINFO, &cache) == 0);
+
+        assert_se((m = sd_netlink_message_unref(m)) == NULL);
+        assert_se((r = sd_netlink_message_unref(r)) == NULL);
+
+}
+
+static void test_route(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL;
+        struct in_addr addr, addr_data;
+        uint32_t index = 2, u32_data;
+        int r;
+
+        r = sd_rtnl_message_new_route(rtnl, &req, RTM_NEWROUTE, AF_INET, RTPROT_STATIC);
+        if (r < 0) {
+                log_error_errno(r, "Could not create RTM_NEWROUTE message: %m");
+                return;
+        }
+
+        addr.s_addr = htobe32(INADDR_LOOPBACK);
+
+        r = sd_netlink_message_append_in_addr(req, RTA_GATEWAY, &addr);
+        if (r < 0) {
+                log_error_errno(r, "Could not append RTA_GATEWAY attribute: %m");
+                return;
+        }
+
+        r = sd_netlink_message_append_u32(req, RTA_OIF, index);
+        if (r < 0) {
+                log_error_errno(r, "Could not append RTA_OIF attribute: %m");
+                return;
+        }
+
+        assert_se(sd_netlink_message_rewind(req, NULL) >= 0);
+
+        assert_se(sd_netlink_message_read_in_addr(req, RTA_GATEWAY, &addr_data) >= 0);
+        assert_se(addr_data.s_addr == addr.s_addr);
+
+        assert_se(sd_netlink_message_read_u32(req, RTA_OIF, &u32_data) >= 0);
+        assert_se(u32_data == index);
+
+        assert_se((req = sd_netlink_message_unref(req)) == NULL);
+}
+
+static void test_multiple(void) {
+        sd_netlink *rtnl1, *rtnl2;
+
+        assert_se(sd_netlink_open(&rtnl1) >= 0);
+        assert_se(sd_netlink_open(&rtnl2) >= 0);
+
+        rtnl1 = sd_netlink_unref(rtnl1);
+        rtnl2 = sd_netlink_unref(rtnl2);
+}
+
+static int link_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
+        char *ifname = userdata;
+        const char *data;
+
+        assert_se(rtnl);
+        assert_se(m);
+        assert_se(userdata);
+
+        log_info("%s: got link info about %s", __func__, ifname);
+        free(ifname);
+
+        assert_se(sd_netlink_message_read_string(m, IFLA_IFNAME, &data) >= 0);
+        assert_se(streq(data, "lo"));
+
+        return 1;
+}
+
+static void test_event_loop(int ifindex) {
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        char *ifname;
+
+        ifname = strdup("lo2");
+        assert_se(ifname);
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+
+        assert_se(sd_netlink_call_async(rtnl, NULL, m, link_handler, NULL, ifname, 0, NULL) >= 0);
+
+        assert_se(sd_event_default(&event) >= 0);
+
+        assert_se(sd_netlink_attach_event(rtnl, event, 0) >= 0);
+
+        assert_se(sd_event_run(event, 0) >= 0);
+
+        assert_se(sd_netlink_detach_event(rtnl) >= 0);
+
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+}
+
+static void test_async_destroy(void *userdata) {
+}
+
+static void test_async(int ifindex) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *r = NULL;
+        _cleanup_(sd_netlink_slot_unrefp) sd_netlink_slot *slot = NULL;
+        sd_netlink_destroy_t destroy_callback;
+        const char *description;
+        char *ifname;
+
+        ifname = strdup("lo");
+        assert_se(ifname);
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+
+        assert_se(sd_netlink_call_async(rtnl, &slot, m, link_handler, test_async_destroy, ifname, 0, "hogehoge") >= 0);
+
+        assert_se(sd_netlink_slot_get_netlink(slot) == rtnl);
+        assert_se(sd_netlink_slot_get_userdata(slot) == ifname);
+        assert_se(sd_netlink_slot_get_destroy_callback(slot, &destroy_callback) == 1);
+        assert_se(destroy_callback == test_async_destroy);
+        assert_se(sd_netlink_slot_get_floating(slot) == 0);
+        assert_se(sd_netlink_slot_get_description(slot, &description) == 1);
+        assert_se(streq(description, "hogehoge"));
+
+        assert_se(sd_netlink_wait(rtnl, 0) >= 0);
+        assert_se(sd_netlink_process(rtnl, &r) >= 0);
+
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+}
+
+static void test_slot_set(int ifindex) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *r = NULL;
+        _cleanup_(sd_netlink_slot_unrefp) sd_netlink_slot *slot = NULL;
+        sd_netlink_destroy_t destroy_callback;
+        const char *description;
+        char *ifname;
+
+        ifname = strdup("lo");
+        assert_se(ifname);
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+
+        assert_se(sd_netlink_call_async(rtnl, &slot, m, link_handler, NULL, NULL, 0, NULL) >= 0);
+
+        assert_se(sd_netlink_slot_get_netlink(slot) == rtnl);
+        assert_se(!sd_netlink_slot_get_userdata(slot));
+        assert_se(!sd_netlink_slot_set_userdata(slot, ifname));
+        assert_se(sd_netlink_slot_get_userdata(slot) == ifname);
+        assert_se(sd_netlink_slot_get_destroy_callback(slot, NULL) == 0);
+        assert_se(sd_netlink_slot_set_destroy_callback(slot, test_async_destroy) >= 0);
+        assert_se(sd_netlink_slot_get_destroy_callback(slot, &destroy_callback) == 1);
+        assert_se(destroy_callback == test_async_destroy);
+        assert_se(sd_netlink_slot_get_floating(slot) == 0);
+        assert_se(sd_netlink_slot_set_floating(slot, 1) == 1);
+        assert_se(sd_netlink_slot_get_floating(slot) == 1);
+        assert_se(sd_netlink_slot_get_description(slot, NULL) == 0);
+        assert_se(sd_netlink_slot_set_description(slot, "hogehoge") >= 0);
+        assert_se(sd_netlink_slot_get_description(slot, &description) == 1);
+        assert_se(streq(description, "hogehoge"));
+
+        assert_se(sd_netlink_wait(rtnl, 0) >= 0);
+        assert_se(sd_netlink_process(rtnl, &r) >= 0);
+
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+}
+
+struct test_async_object {
+        unsigned n_ref;
+        char *ifname;
+};
+
+static struct test_async_object *test_async_object_free(struct test_async_object *t) {
+        assert(t);
+
+        free(t->ifname);
+        return mfree(t);
+}
+
+DEFINE_PRIVATE_TRIVIAL_REF_UNREF_FUNC(struct test_async_object, test_async_object, test_async_object_free);
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct test_async_object *, test_async_object_unref);
+
+static int link_handler2(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
+        struct test_async_object *t = userdata;
+        const char *data;
+
+        assert_se(rtnl);
+        assert_se(m);
+        assert_se(userdata);
+
+        log_info("%s: got link info about %s", __func__, t->ifname);
+
+        assert_se(sd_netlink_message_read_string(m, IFLA_IFNAME, &data) >= 0);
+        assert_se(streq(data, "lo"));
+
+        return 1;
+}
+
+static void test_async_object_destroy(void *userdata) {
+        struct test_async_object *t = userdata;
+
+        assert(userdata);
+
+        log_info("%s: n_ref=%u", __func__, t->n_ref);
+        test_async_object_unref(t);
+}
+
+static void test_async_destroy_callback(int ifindex) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *r = NULL;
+        _cleanup_(test_async_object_unrefp) struct test_async_object *t = NULL;
+        _cleanup_(sd_netlink_slot_unrefp) sd_netlink_slot *slot = NULL;
+        char *ifname;
+
+        assert_se(t = new(struct test_async_object, 1));
+        assert_se(ifname = strdup("lo"));
+        *t = (struct test_async_object) {
+                .n_ref = 1,
+                .ifname = ifname,
+        };
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+
+        /* destroy callback is called after processing message */
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+        assert_se(sd_netlink_call_async(rtnl, NULL, m, link_handler2, test_async_object_destroy, t, 0, NULL) >= 0);
+
+        assert_se(t->n_ref == 1);
+        assert_se(test_async_object_ref(t));
+        assert_se(t->n_ref == 2);
+
+        assert_se(sd_netlink_wait(rtnl, 0) >= 0);
+        assert_se(sd_netlink_process(rtnl, &r) == 1);
+        assert_se(t->n_ref == 1);
+
+        assert_se(!sd_netlink_message_unref(m));
+
+        /* destroy callback is called when asynchronous call is cancelled, that is, slot is freed. */
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+        assert_se(sd_netlink_call_async(rtnl, &slot, m, link_handler2, test_async_object_destroy, t, 0, NULL) >= 0);
+
+        assert_se(t->n_ref == 1);
+        assert_se(test_async_object_ref(t));
+        assert_se(t->n_ref == 2);
+
+        assert_se(!(slot = sd_netlink_slot_unref(slot)));
+        assert_se(t->n_ref == 1);
+
+        assert_se(!sd_netlink_message_unref(m));
+
+        /* destroy callback is also called by sd_netlink_unref() */
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, ifindex) >= 0);
+        assert_se(sd_netlink_call_async(rtnl, NULL, m, link_handler2, test_async_object_destroy, t, 0, NULL) >= 0);
+
+        assert_se(t->n_ref == 1);
+        assert_se(test_async_object_ref(t));
+        assert_se(t->n_ref == 2);
+
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+        assert_se(t->n_ref == 1);
+}
+
+static int pipe_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
+        int *counter = userdata;
+        int r;
+
+        (*counter)--;
+
+        r = sd_netlink_message_get_errno(m);
+
+        log_info_errno(r, "%d left in pipe. got reply: %m", *counter);
+
+        assert_se(r >= 0);
+
+        return 1;
+}
+
+static void test_pipe(int ifindex) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m1 = NULL, *m2 = NULL;
+        int counter = 0;
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m1, RTM_GETLINK, ifindex) >= 0);
+        assert_se(sd_rtnl_message_new_link(rtnl, &m2, RTM_GETLINK, ifindex) >= 0);
+
+        counter++;
+        assert_se(sd_netlink_call_async(rtnl, NULL, m1, pipe_handler, NULL, &counter, 0, NULL) >= 0);
+
+        counter++;
+        assert_se(sd_netlink_call_async(rtnl, NULL, m2, pipe_handler, NULL, &counter, 0, NULL) >= 0);
+
+        while (counter > 0) {
+                assert_se(sd_netlink_wait(rtnl, 0) >= 0);
+                assert_se(sd_netlink_process(rtnl, NULL) >= 0);
+        }
+
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+}
+
+static void test_container(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        uint16_t u16_data;
+        uint32_t u32_data;
+        const char *string_data;
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINK, 0) >= 0);
+
+        assert_se(sd_netlink_message_open_container(m, IFLA_LINKINFO) >= 0);
+        assert_se(sd_netlink_message_open_container_union(m, IFLA_INFO_DATA, "vlan") >= 0);
+        assert_se(sd_netlink_message_append_u16(m, IFLA_VLAN_ID, 100) >= 0);
+        assert_se(sd_netlink_message_close_container(m) >= 0);
+        assert_se(sd_netlink_message_append_string(m, IFLA_INFO_KIND, "vlan") >= 0);
+        assert_se(sd_netlink_message_close_container(m) >= 0);
+        assert_se(sd_netlink_message_close_container(m) == -EINVAL);
+
+        assert_se(sd_netlink_message_rewind(m, NULL) >= 0);
+
+        assert_se(sd_netlink_message_enter_container(m, IFLA_LINKINFO) >= 0);
+        assert_se(sd_netlink_message_read_string(m, IFLA_INFO_KIND, &string_data) >= 0);
+        assert_se(streq("vlan", string_data));
+
+        assert_se(sd_netlink_message_enter_container(m, IFLA_INFO_DATA) >= 0);
+        assert_se(sd_netlink_message_read_u16(m, IFLA_VLAN_ID, &u16_data) >= 0);
+        assert_se(sd_netlink_message_exit_container(m) >= 0);
+
+        assert_se(sd_netlink_message_read_string(m, IFLA_INFO_KIND, &string_data) >= 0);
+        assert_se(streq("vlan", string_data));
+        assert_se(sd_netlink_message_exit_container(m) >= 0);
+
+        assert_se(sd_netlink_message_read_u32(m, IFLA_LINKINFO, &u32_data) < 0);
+
+        assert_se(sd_netlink_message_exit_container(m) == -EINVAL);
+}
+
+static void test_match(void) {
+        _cleanup_(sd_netlink_slot_unrefp) sd_netlink_slot *s1 = NULL, *s2 = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+
+        assert_se(sd_netlink_add_match(rtnl, &s1, RTM_NEWLINK, link_handler, NULL, NULL, NULL) >= 0);
+        assert_se(sd_netlink_add_match(rtnl, &s2, RTM_NEWLINK, link_handler, NULL, NULL, NULL) >= 0);
+        assert_se(sd_netlink_add_match(rtnl, NULL, RTM_NEWLINK, link_handler, NULL, NULL, NULL) >= 0);
+
+        assert_se(!(s1 = sd_netlink_slot_unref(s1)));
+        assert_se(!(s2 = sd_netlink_slot_unref(s2)));
+
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+}
+
+static void test_get_addresses(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
+        sd_netlink_message *m;
+
+        assert_se(sd_rtnl_message_new_addr(rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC) >= 0);
+
+        assert_se(sd_netlink_call(rtnl, req, 0, &reply) >= 0);
+
+        for (m = reply; m; m = sd_netlink_message_next(m)) {
+                uint16_t type;
+                unsigned char scope, flags;
+                int family, ifindex;
+
+                assert_se(sd_netlink_message_get_type(m, &type) >= 0);
+                assert_se(type == RTM_NEWADDR);
+
+                assert_se(sd_rtnl_message_addr_get_ifindex(m, &ifindex) >= 0);
+                assert_se(sd_rtnl_message_addr_get_family(m, &family) >= 0);
+                assert_se(sd_rtnl_message_addr_get_scope(m, &scope) >= 0);
+                assert_se(sd_rtnl_message_addr_get_flags(m, &flags) >= 0);
+
+                assert_se(ifindex > 0);
+                assert_se(IN_SET(family, AF_INET, AF_INET6));
+
+                log_info("got IPv%u address on ifindex %i", family == AF_INET ? 4: 6, ifindex);
+        }
+}
+
+static void test_message(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+
+        assert_se(rtnl_message_new_synthetic_error(rtnl, -ETIMEDOUT, 1, &m) >= 0);
+        assert_se(sd_netlink_message_get_errno(m) == -ETIMEDOUT);
+}
+
+static void test_array(void) {
+        _cleanup_(sd_netlink_unrefp) sd_netlink *genl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+
+        assert_se(sd_genl_socket_open(&genl) >= 0);
+        assert_se(sd_genl_message_new(genl, SD_GENL_ID_CTRL, CTRL_CMD_GETFAMILY, &m) >= 0);
+
+        assert_se(sd_netlink_message_open_container(m, CTRL_ATTR_MCAST_GROUPS) >= 0);
+        for (unsigned i = 0; i < 10; i++) {
+                char name[STRLEN("hoge") + DECIMAL_STR_MAX(uint32_t)];
+                uint32_t id = i + 1000;
+
+                xsprintf(name, "hoge%" PRIu32, id);
+                assert_se(sd_netlink_message_open_array(m, i + 1) >= 0);
+                assert_se(sd_netlink_message_append_u32(m, CTRL_ATTR_MCAST_GRP_ID, id) >= 0);
+                assert_se(sd_netlink_message_append_string(m, CTRL_ATTR_MCAST_GRP_NAME, name) >= 0);
+                assert_se(sd_netlink_message_close_container(m) >= 0);
+        }
+        assert_se(sd_netlink_message_close_container(m) >= 0);
+
+        rtnl_message_seal(m);
+        assert_se(sd_netlink_message_rewind(m, genl) >= 0);
+
+        assert_se(sd_netlink_message_enter_container(m, CTRL_ATTR_MCAST_GROUPS) >= 0);
+        for (unsigned i = 0; i < 10; i++) {
+                char expected[STRLEN("hoge") + DECIMAL_STR_MAX(uint32_t)];
+                const char *name;
+                uint32_t id;
+
+                assert_se(sd_netlink_message_enter_array(m, i + 1) >= 0);
+                assert_se(sd_netlink_message_read_u32(m, CTRL_ATTR_MCAST_GRP_ID, &id) >= 0);
+                assert_se(sd_netlink_message_read_string(m, CTRL_ATTR_MCAST_GRP_NAME, &name) >= 0);
+                assert_se(sd_netlink_message_exit_container(m) >= 0);
+
+                assert_se(id == i + 1000);
+                xsprintf(expected, "hoge%" PRIu32, id);
+                assert_se(streq(name, expected));
+        }
+        assert_se(sd_netlink_message_exit_container(m) >= 0);
+}
+
+static void test_strv(sd_netlink *rtnl) {
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
+        _cleanup_strv_free_ char **names_in = NULL, **names_out;
+        const char *p;
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINKPROP, 1) >= 0);
+
+        for (unsigned i = 0; i < 10; i++) {
+                char name[STRLEN("hoge") + DECIMAL_STR_MAX(uint32_t)];
+
+                xsprintf(name, "hoge%" PRIu32, i + 1000);
+                assert_se(strv_extend(&names_in, name) >= 0);
+        }
+
+        assert_se(sd_netlink_message_open_container(m, IFLA_PROP_LIST) >= 0);
+        assert_se(sd_netlink_message_append_strv(m, IFLA_ALT_IFNAME, names_in) >= 0);
+        assert_se(sd_netlink_message_close_container(m) >= 0);
+
+        rtnl_message_seal(m);
+        assert_se(sd_netlink_message_rewind(m, NULL) >= 0);
+
+        assert_se(sd_netlink_message_read_strv(m, IFLA_PROP_LIST, IFLA_ALT_IFNAME, &names_out) >= 0);
+        assert_se(strv_equal(names_in, names_out));
+
+        assert_se(sd_netlink_message_enter_container(m, IFLA_PROP_LIST) >= 0);
+        assert_se(sd_netlink_message_read_string(m, IFLA_ALT_IFNAME, &p) >= 0);
+        assert_se(streq(p, "hoge1009"));
+        assert_se(sd_netlink_message_exit_container(m) >= 0);
+}
+
+int main(void) {
+        sd_netlink *rtnl;
+        sd_netlink_message *m;
+        sd_netlink_message *r;
+        const char *string_data;
+        int if_loopback;
+        uint16_t type;
+
+        test_match();
+        test_multiple();
+
+        assert_se(sd_netlink_open(&rtnl) >= 0);
+        assert_se(rtnl);
+
+        test_route(rtnl);
+        test_message(rtnl);
+        test_container(rtnl);
+        test_array();
+        test_strv(rtnl);
+
+        if_loopback = (int) if_nametoindex("lo");
+        assert_se(if_loopback > 0);
+
+        test_async(if_loopback);
+        test_slot_set(if_loopback);
+        test_async_destroy_callback(if_loopback);
+        test_pipe(if_loopback);
+        test_event_loop(if_loopback);
+        test_link_configure(rtnl, if_loopback);
+
+        test_get_addresses(rtnl);
+        test_message_link_bridge(rtnl);
+
+        assert_se(sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, if_loopback) >= 0);
+        assert_se(m);
+
+        assert_se(sd_netlink_message_get_type(m, &type) >= 0);
+        assert_se(type == RTM_GETLINK);
+
+        assert_se(sd_netlink_message_read_string(m, IFLA_IFNAME, &string_data) == -EPERM);
+
+        assert_se(sd_netlink_call(rtnl, m, 0, &r) == 1);
+        assert_se(sd_netlink_message_get_type(r, &type) >= 0);
+        assert_se(type == RTM_NEWLINK);
+
+        assert_se((r = sd_netlink_message_unref(r)) == NULL);
+
+        assert_se(sd_netlink_call(rtnl, m, -1, &r) == -EPERM);
+        assert_se((m = sd_netlink_message_unref(m)) == NULL);
+        assert_se((r = sd_netlink_message_unref(r)) == NULL);
+
+        test_link_get(rtnl, if_loopback);
+        test_address_get(rtnl, if_loopback);
+
+        assert_se((m = sd_netlink_message_unref(m)) == NULL);
+        assert_se((r = sd_netlink_message_unref(r)) == NULL);
+        assert_se((rtnl = sd_netlink_unref(rtnl)) == NULL);
+
+        return EXIT_SUCCESS;
+}
diff --git a/src/libsystemd/sd-network/network-util.c b/src/libsystemd/sd-network/network-util.c
new file mode 100644
index 0000000..7753431
--- /dev/null
+++ b/src/libsystemd/sd-network/network-util.c
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "network-util.h"
+#include "string-table.h"
+#include "strv.h"
+
+bool network_is_online(void) {
+        _cleanup_free_ char *carrier_state = NULL, *addr_state = NULL;
+        int r;
+
+        r = sd_network_get_carrier_state(&carrier_state);
+        if (r < 0) /* if we don't know anything, we consider the system online */
+                return true;
+
+        r = sd_network_get_address_state(&addr_state);
+        if (r < 0) /* if we don't know anything, we consider the system online */
+                return true;
+
+        if (STR_IN_SET(carrier_state, "degraded-carrier", "carrier") &&
+            STR_IN_SET(addr_state, "routable", "degraded"))
+                return true;
+
+        return false;
+}
+
+static const char* const link_operstate_table[_LINK_OPERSTATE_MAX] = {
+        [LINK_OPERSTATE_MISSING]          = "missing",
+        [LINK_OPERSTATE_OFF]              = "off",
+        [LINK_OPERSTATE_NO_CARRIER]       = "no-carrier",
+        [LINK_OPERSTATE_DORMANT]          = "dormant",
+        [LINK_OPERSTATE_DEGRADED_CARRIER] = "degraded-carrier",
+        [LINK_OPERSTATE_CARRIER]          = "carrier",
+        [LINK_OPERSTATE_DEGRADED]         = "degraded",
+        [LINK_OPERSTATE_ENSLAVED]         = "enslaved",
+        [LINK_OPERSTATE_ROUTABLE]         = "routable",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(link_operstate, LinkOperationalState);
+
+static const char* const link_carrier_state_table[_LINK_CARRIER_STATE_MAX] = {
+        [LINK_CARRIER_STATE_OFF]              = "off",
+        [LINK_CARRIER_STATE_NO_CARRIER]       = "no-carrier",
+        [LINK_CARRIER_STATE_DORMANT]          = "dormant",
+        [LINK_CARRIER_STATE_DEGRADED_CARRIER] = "degraded-carrier",
+        [LINK_CARRIER_STATE_CARRIER]          = "carrier",
+        [LINK_CARRIER_STATE_ENSLAVED]         = "enslaved",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(link_carrier_state, LinkCarrierState);
+
+static const char* const link_address_state_table[_LINK_ADDRESS_STATE_MAX] = {
+        [LINK_ADDRESS_STATE_OFF]      = "off",
+        [LINK_ADDRESS_STATE_DEGRADED] = "degraded",
+        [LINK_ADDRESS_STATE_ROUTABLE] = "routable",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(link_address_state, LinkAddressState);
+
+int parse_operational_state_range(const char *str, LinkOperationalStateRange *out) {
+        LinkOperationalStateRange range = { _LINK_OPERSTATE_INVALID, _LINK_OPERSTATE_INVALID };
+        _cleanup_free_ const char *min = NULL;
+        const char *p;
+
+        assert(str);
+        assert(out);
+
+        p = strchr(str, ':');
+        if (p) {
+                min = strndup(str, p - str);
+
+                if (!isempty(p + 1)) {
+                        range.max = link_operstate_from_string(p + 1);
+                        if (range.max < 0)
+                                return -EINVAL;
+                }
+        } else
+                min = strdup(str);
+
+        if (!min)
+                return -ENOMEM;
+
+        if (!isempty(min)) {
+                range.min = link_operstate_from_string(min);
+                if (range.min < 0)
+                        return -EINVAL;
+        }
+
+        /* Fail on empty strings. */
+        if (range.min == _LINK_OPERSTATE_INVALID && range.max == _LINK_OPERSTATE_INVALID)
+                return -EINVAL;
+
+        if (range.min == _LINK_OPERSTATE_INVALID)
+                range.min = LINK_OPERSTATE_MISSING;
+        if (range.max == _LINK_OPERSTATE_INVALID)
+                range.max = LINK_OPERSTATE_ROUTABLE;
+
+        if (range.min > range.max)
+                return -EINVAL;
+
+        *out = range;
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-network/network-util.h b/src/libsystemd/sd-network/network-util.h
new file mode 100644
index 0000000..8cfd894
--- /dev/null
+++ b/src/libsystemd/sd-network/network-util.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-network.h"
+
+#include "macro.h"
+
+bool network_is_online(void);
+
+typedef enum LinkOperationalState {
+        LINK_OPERSTATE_MISSING,
+        LINK_OPERSTATE_OFF,
+        LINK_OPERSTATE_NO_CARRIER,
+        LINK_OPERSTATE_DORMANT,
+        LINK_OPERSTATE_DEGRADED_CARRIER,
+        LINK_OPERSTATE_CARRIER,
+        LINK_OPERSTATE_DEGRADED,
+        LINK_OPERSTATE_ENSLAVED,
+        LINK_OPERSTATE_ROUTABLE,
+        _LINK_OPERSTATE_MAX,
+        _LINK_OPERSTATE_INVALID = -1
+} LinkOperationalState;
+
+typedef enum LinkCarrierState {
+        LINK_CARRIER_STATE_OFF              = LINK_OPERSTATE_OFF,
+        LINK_CARRIER_STATE_NO_CARRIER       = LINK_OPERSTATE_NO_CARRIER,
+        LINK_CARRIER_STATE_DORMANT          = LINK_OPERSTATE_DORMANT,
+        LINK_CARRIER_STATE_DEGRADED_CARRIER = LINK_OPERSTATE_DEGRADED_CARRIER,
+        LINK_CARRIER_STATE_CARRIER          = LINK_OPERSTATE_CARRIER,
+        LINK_CARRIER_STATE_ENSLAVED         = LINK_OPERSTATE_ENSLAVED,
+        _LINK_CARRIER_STATE_MAX,
+        _LINK_CARRIER_STATE_INVALID = -1
+} LinkCarrierState;
+
+typedef enum LinkAddressState {
+        LINK_ADDRESS_STATE_OFF,
+        LINK_ADDRESS_STATE_DEGRADED,
+        LINK_ADDRESS_STATE_ROUTABLE,
+        _LINK_ADDRESS_STATE_MAX,
+        _LINK_ADDRESS_STATE_INVALID = -1
+} LinkAddressState;
+
+const char* link_operstate_to_string(LinkOperationalState s) _const_;
+LinkOperationalState link_operstate_from_string(const char *s) _pure_;
+
+const char* link_carrier_state_to_string(LinkCarrierState s) _const_;
+LinkCarrierState link_carrier_state_from_string(const char *s) _pure_;
+
+const char* link_address_state_to_string(LinkAddressState s) _const_;
+LinkAddressState link_address_state_from_string(const char *s) _pure_;
+
+typedef struct LinkOperationalStateRange {
+        LinkOperationalState min;
+        LinkOperationalState max;
+} LinkOperationalStateRange;
+
+#define LINK_OPERSTATE_RANGE_DEFAULT (LinkOperationalStateRange) { LINK_OPERSTATE_DEGRADED, \
+                                                                   LINK_OPERSTATE_ROUTABLE }
+
+int parse_operational_state_range(const char *str, LinkOperationalStateRange *out);
diff --git a/src/libsystemd/sd-network/sd-network.c b/src/libsystemd/sd-network/sd-network.c
new file mode 100644
index 0000000..b9b1099
--- /dev/null
+++ b/src/libsystemd/sd-network/sd-network.c
@@ -0,0 +1,448 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <poll.h>
+#include <sys/inotify.h>
+
+#include "sd-network.h"
+
+#include "alloc-util.h"
+#include "env-file.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "util.h"
+
+static int network_get_string(const char *field, char **ret) {
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = parse_env_file(NULL, "/run/systemd/netif/state", field, &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+
+        *ret = TAKE_PTR(s);
+
+        return 0;
+}
+
+_public_ int sd_network_get_operational_state(char **state) {
+        return network_get_string("OPER_STATE", state);
+}
+
+_public_ int sd_network_get_carrier_state(char **state) {
+        return network_get_string("CARRIER_STATE", state);
+}
+
+_public_ int sd_network_get_address_state(char **state) {
+        return network_get_string("ADDRESS_STATE", state);
+}
+
+static int network_get_strv(const char *key, char ***ret) {
+        _cleanup_strv_free_ char **a = NULL;
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = parse_env_file(NULL, "/run/systemd/netif/state", key, &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+        if (isempty(s)) {
+                *ret = NULL;
+                return 0;
+        }
+
+        a = strv_split(s, " ");
+        if (!a)
+                return -ENOMEM;
+
+        strv_uniq(a);
+        r = (int) strv_length(a);
+
+        *ret = TAKE_PTR(a);
+
+        return r;
+}
+
+_public_ int sd_network_get_dns(char ***ret) {
+        return network_get_strv("DNS", ret);
+}
+
+_public_ int sd_network_get_ntp(char ***ret) {
+        return network_get_strv("NTP", ret);
+}
+
+_public_ int sd_network_get_search_domains(char ***ret) {
+        return network_get_strv("DOMAINS", ret);
+}
+
+_public_ int sd_network_get_route_domains(char ***ret) {
+        return network_get_strv("ROUTE_DOMAINS", ret);
+}
+
+static int network_link_get_string(int ifindex, const char *field, char **ret) {
+        char path[STRLEN("/run/systemd/netif/links/") + DECIMAL_STR_MAX(ifindex) + 1];
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        xsprintf(path, "/run/systemd/netif/links/%i", ifindex);
+
+        r = parse_env_file(NULL, path, field, &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+
+        *ret = TAKE_PTR(s);
+
+        return 0;
+}
+
+static int network_link_get_strv(int ifindex, const char *key, char ***ret) {
+        char path[STRLEN("/run/systemd/netif/links/") + DECIMAL_STR_MAX(ifindex) + 1];
+        _cleanup_strv_free_ char **a = NULL;
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        xsprintf(path, "/run/systemd/netif/links/%i", ifindex);
+        r = parse_env_file(NULL, path, key, &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+        if (isempty(s)) {
+                *ret = NULL;
+                return 0;
+        }
+
+        a = strv_split(s, " ");
+        if (!a)
+                return -ENOMEM;
+
+        strv_uniq(a);
+        r = (int) strv_length(a);
+
+        *ret = TAKE_PTR(a);
+
+        return r;
+}
+
+_public_ int sd_network_link_get_setup_state(int ifindex, char **state) {
+        return network_link_get_string(ifindex, "ADMIN_STATE", state);
+}
+
+_public_ int sd_network_link_get_network_file(int ifindex, char **filename) {
+        return network_link_get_string(ifindex, "NETWORK_FILE", filename);
+}
+
+_public_ int sd_network_link_get_operational_state(int ifindex, char **state) {
+        return network_link_get_string(ifindex, "OPER_STATE", state);
+}
+
+_public_ int sd_network_link_get_carrier_state(int ifindex, char **state) {
+        return network_link_get_string(ifindex, "CARRIER_STATE", state);
+}
+
+_public_ int sd_network_link_get_address_state(int ifindex, char **state) {
+        return network_link_get_string(ifindex, "ADDRESS_STATE", state);
+}
+
+_public_ int sd_network_link_get_dhcp6_client_iaid_string(int ifindex, char **iaid) {
+        return network_link_get_string(ifindex, "DHCP6_CLIENT_IAID", iaid);
+}
+
+_public_ int sd_network_link_get_dhcp6_client_duid_string(int ifindex, char **duid) {
+        return network_link_get_string(ifindex, "DHCP6_CLIENT_DUID", duid);
+}
+
+_public_ int sd_network_link_get_required_for_online(int ifindex) {
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        r = network_link_get_string(ifindex, "REQUIRED_FOR_ONLINE", &s);
+        if (r < 0) {
+                /* Handle -ENODATA as RequiredForOnline=yes, for compatibility */
+                if (r == -ENODATA)
+                        return true;
+                return r;
+        }
+
+        return parse_boolean(s);
+}
+
+_public_ int sd_network_link_get_required_operstate_for_online(int ifindex, char **state) {
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert_return(state, -EINVAL);
+
+        r = network_link_get_string(ifindex, "REQUIRED_OPER_STATE_FOR_ONLINE", &s);
+        if (r < 0) {
+                if (r != -ENODATA)
+                        return r;
+
+                /* For compatibility, assuming degraded. */
+                s = strdup("degraded");
+                if (!s)
+                        return -ENOMEM;
+        }
+
+        *state = TAKE_PTR(s);
+        return 0;
+}
+
+_public_ int sd_network_link_get_llmnr(int ifindex, char **llmnr) {
+        return network_link_get_string(ifindex, "LLMNR", llmnr);
+}
+
+_public_ int sd_network_link_get_mdns(int ifindex, char **mdns) {
+        return network_link_get_string(ifindex, "MDNS", mdns);
+}
+
+_public_ int sd_network_link_get_dns_over_tls(int ifindex, char **dns_over_tls) {
+        return network_link_get_string(ifindex, "DNS_OVER_TLS", dns_over_tls);
+}
+
+_public_ int sd_network_link_get_dnssec(int ifindex, char **dnssec) {
+        return network_link_get_string(ifindex, "DNSSEC", dnssec);
+}
+
+_public_ int sd_network_link_get_dnssec_negative_trust_anchors(int ifindex, char ***nta) {
+        return network_link_get_strv(ifindex, "DNSSEC_NTA", nta);
+}
+
+_public_ int sd_network_link_get_dns(int ifindex, char ***ret) {
+        return network_link_get_strv(ifindex, "DNS", ret);
+}
+
+_public_ int sd_network_link_get_ntp(int ifindex, char ***ret) {
+        return network_link_get_strv(ifindex, "NTP", ret);
+}
+
+_public_ int sd_network_link_get_sip(int ifindex, char ***ret) {
+        return network_link_get_strv(ifindex, "SIP", ret);
+}
+
+_public_ int sd_network_link_get_search_domains(int ifindex, char ***ret) {
+        return network_link_get_strv(ifindex, "DOMAINS", ret);
+}
+
+_public_ int sd_network_link_get_route_domains(int ifindex, char ***ret) {
+        return network_link_get_strv(ifindex, "ROUTE_DOMAINS", ret);
+}
+
+_public_ int sd_network_link_get_dns_default_route(int ifindex) {
+        char path[STRLEN("/run/systemd/netif/links/") + DECIMAL_STR_MAX(ifindex) + 1];
+        _cleanup_free_ char *s = NULL;
+        int r;
+
+        assert_return(ifindex > 0, -EINVAL);
+
+        xsprintf(path, "/run/systemd/netif/links/%i", ifindex);
+
+        r = parse_env_file(NULL, path, "DNS_DEFAULT_ROUTE", &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+        if (isempty(s))
+                return -ENODATA;
+        return parse_boolean(s);
+}
+
+static int network_link_get_ifindexes(int ifindex, const char *key, int **ret) {
+        char path[STRLEN("/run/systemd/netif/links/") + DECIMAL_STR_MAX(ifindex) + 1];
+        _cleanup_free_ int *ifis = NULL;
+        _cleanup_free_ char *s = NULL;
+        size_t allocated = 0, c = 0;
+        int r;
+
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        xsprintf(path, "/run/systemd/netif/links/%i", ifindex);
+        r = parse_env_file(NULL, path, key, &s);
+        if (r == -ENOENT)
+                return -ENODATA;
+        if (r < 0)
+                return r;
+
+        for (const char *x = s;;) {
+                _cleanup_free_ char *word = NULL;
+
+                r = extract_first_word(&x, &word, NULL, 0);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                if (!GREEDY_REALLOC(ifis, allocated, c + 2))
+                        return -ENOMEM;
+
+                r = ifis[c++] = parse_ifindex(word);
+                if (r < 0)
+                        return r;
+        }
+
+        if (ifis)
+                ifis[c] = 0; /* Let's add a 0 ifindex to the end, to be nice */
+
+        *ret = TAKE_PTR(ifis);
+
+        return c;
+}
+
+_public_ int sd_network_link_get_carrier_bound_to(int ifindex, int **ret) {
+        return network_link_get_ifindexes(ifindex, "CARRIER_BOUND_TO", ret);
+}
+
+_public_ int sd_network_link_get_carrier_bound_by(int ifindex, int **ret) {
+        return network_link_get_ifindexes(ifindex, "CARRIER_BOUND_BY", ret);
+}
+
+static int MONITOR_TO_FD(sd_network_monitor *m) {
+        return (int) (unsigned long) m - 1;
+}
+
+static sd_network_monitor* FD_TO_MONITOR(int fd) {
+        return (sd_network_monitor*) (unsigned long) (fd + 1);
+}
+
+static int monitor_add_inotify_watch(int fd) {
+        int k;
+
+        k = inotify_add_watch(fd, "/run/systemd/netif/links/", IN_MOVED_TO|IN_DELETE);
+        if (k >= 0)
+                return 0;
+        else if (errno != ENOENT)
+                return -errno;
+
+        k = inotify_add_watch(fd, "/run/systemd/netif/", IN_CREATE|IN_ISDIR);
+        if (k >= 0)
+                return 0;
+        else if (errno != ENOENT)
+                return -errno;
+
+        k = inotify_add_watch(fd, "/run/systemd/", IN_CREATE|IN_ISDIR);
+        if (k < 0)
+                return -errno;
+
+        return 0;
+}
+
+_public_ int sd_network_monitor_new(sd_network_monitor **m, const char *category) {
+        _cleanup_close_ int fd = -1;
+        int k;
+        bool good = false;
+
+        assert_return(m, -EINVAL);
+
+        fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        if (!category || streq(category, "links")) {
+                k = monitor_add_inotify_watch(fd);
+                if (k < 0)
+                        return k;
+
+                good = true;
+        }
+
+        if (!good)
+                return -EINVAL;
+
+        *m = FD_TO_MONITOR(TAKE_FD(fd));
+        return 0;
+}
+
+_public_ sd_network_monitor* sd_network_monitor_unref(sd_network_monitor *m) {
+        if (m)
+                close_nointr(MONITOR_TO_FD(m));
+
+        return NULL;
+}
+
+_public_ int sd_network_monitor_flush(sd_network_monitor *m) {
+        union inotify_event_buffer buffer;
+        struct inotify_event *e;
+        ssize_t l;
+        int fd, k;
+
+        assert_return(m, -EINVAL);
+
+        fd = MONITOR_TO_FD(m);
+
+        l = read(fd, &buffer, sizeof(buffer));
+        if (l < 0) {
+                if (IN_SET(errno, EAGAIN, EINTR))
+                        return 0;
+
+                return -errno;
+        }
+
+        FOREACH_INOTIFY_EVENT(e, buffer, l) {
+                if (e->mask & IN_ISDIR) {
+                        k = monitor_add_inotify_watch(fd);
+                        if (k < 0)
+                                return k;
+
+                        k = inotify_rm_watch(fd, e->wd);
+                        if (k < 0)
+                                return -errno;
+                }
+        }
+
+        return 0;
+}
+
+_public_ int sd_network_monitor_get_fd(sd_network_monitor *m) {
+
+        assert_return(m, -EINVAL);
+
+        return MONITOR_TO_FD(m);
+}
+
+_public_ int sd_network_monitor_get_events(sd_network_monitor *m) {
+
+        assert_return(m, -EINVAL);
+
+        /* For now we will only return POLLIN here, since we don't
+         * need anything else ever for inotify.  However, let's have
+         * this API to keep our options open should we later on need
+         * it. */
+        return POLLIN;
+}
+
+_public_ int sd_network_monitor_get_timeout(sd_network_monitor *m, uint64_t *timeout_usec) {
+
+        assert_return(m, -EINVAL);
+        assert_return(timeout_usec, -EINVAL);
+
+        /* For now we will only return (uint64_t) -1, since we don't
+         * need any timeout. However, let's have this API to keep our
+         * options open should we later on need it. */
+        *timeout_usec = (uint64_t) -1;
+        return 0;
+}
diff --git a/src/libsystemd/sd-path/sd-path.c b/src/libsystemd/sd-path/sd-path.c
new file mode 100644
index 0000000..61ed7cb
--- /dev/null
+++ b/src/libsystemd/sd-path/sd-path.c
@@ -0,0 +1,691 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-path.h"
+
+#include "alloc-util.h"
+#include "architecture.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "path-lookup.h"
+#include "path-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+#include "util.h"
+
+static int from_environment(const char *envname, const char *fallback, const char **ret) {
+        assert(ret);
+
+        if (envname) {
+                const char *e;
+
+                e = secure_getenv(envname);
+                if (e && path_is_absolute(e)) {
+                        *ret = e;
+                        return 0;
+                }
+        }
+
+        if (fallback) {
+                *ret = fallback;
+                return 0;
+        }
+
+        return -ENXIO;
+}
+
+static int from_home_dir(const char *envname, const char *suffix, char **buffer, const char **ret) {
+        _cleanup_free_ char *h = NULL;
+        char *cc = NULL;
+        int r;
+
+        assert(suffix);
+        assert(buffer);
+        assert(ret);
+
+        if (envname) {
+                const char *e = NULL;
+
+                e = secure_getenv(envname);
+                if (e && path_is_absolute(e)) {
+                        *ret = e;
+                        return 0;
+                }
+        }
+
+        r = get_home_dir(&h);
+        if (r < 0)
+                return r;
+
+        cc = path_join(h, suffix);
+        if (!cc)
+                return -ENOMEM;
+
+        *buffer = cc;
+        *ret = cc;
+        return 0;
+}
+
+static int from_user_dir(const char *field, char **buffer, const char **ret) {
+        _cleanup_fclose_ FILE *f = NULL;
+        _cleanup_free_ char *b = NULL;
+        _cleanup_free_ const char *fn = NULL;
+        const char *c = NULL;
+        size_t n;
+        int r;
+
+        assert(field);
+        assert(buffer);
+        assert(ret);
+
+        r = from_home_dir("XDG_CONFIG_HOME", ".config", &b, &c);
+        if (r < 0)
+                return r;
+
+        fn = path_join(c, "user-dirs.dirs");
+        if (!fn)
+                return -ENOMEM;
+
+        f = fopen(fn, "re");
+        if (!f) {
+                if (errno == ENOENT)
+                        goto fallback;
+
+                return -errno;
+        }
+
+        /* This is an awful parse, but it follows closely what
+         * xdg-user-dirs does upstream */
+
+        n = strlen(field);
+        for (;;) {
+                _cleanup_free_ char *line = NULL;
+                char *l, *p, *e;
+
+                r = read_line(f, LONG_LINE_MAX, &line);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                l = strstrip(line);
+
+                if (!strneq(l, field, n))
+                        continue;
+
+                p = l + n;
+                p += strspn(p, WHITESPACE);
+
+                if (*p != '=')
+                        continue;
+                p++;
+
+                p += strspn(p, WHITESPACE);
+
+                if (*p != '"')
+                        continue;
+                p++;
+
+                e = strrchr(p, '"');
+                if (!e)
+                        continue;
+                *e = 0;
+
+                /* Three syntaxes permitted: relative to $HOME, $HOME itself, and absolute path */
+                if (startswith(p, "$HOME/")) {
+                        _cleanup_free_ char *h = NULL;
+                        char *cc;
+
+                        r = get_home_dir(&h);
+                        if (r < 0)
+                                return r;
+
+                        cc = path_join(h, p+5);
+                        if (!cc)
+                                return -ENOMEM;
+
+                        *buffer = cc;
+                        *ret = cc;
+                        return 0;
+                } else if (streq(p, "$HOME")) {
+
+                        r = get_home_dir(buffer);
+                        if (r < 0)
+                                return r;
+
+                        *ret = *buffer;
+                        return 0;
+                } else if (path_is_absolute(p)) {
+                        char *copy;
+
+                        copy = strdup(p);
+                        if (!copy)
+                                return -ENOMEM;
+
+                        *buffer = copy;
+                        *ret = copy;
+                        return 0;
+                }
+        }
+
+fallback:
+        /* The desktop directory defaults to $HOME/Desktop, the others to $HOME */
+        if (streq(field, "XDG_DESKTOP_DIR")) {
+                _cleanup_free_ char *h = NULL;
+                char *cc;
+
+                r = get_home_dir(&h);
+                if (r < 0)
+                        return r;
+
+                cc = path_join(h, "Desktop");
+                if (!cc)
+                        return -ENOMEM;
+
+                *buffer = cc;
+                *ret = cc;
+        } else {
+
+                r = get_home_dir(buffer);
+                if (r < 0)
+                        return r;
+
+                *ret = *buffer;
+        }
+
+        return 0;
+}
+
+static int get_path(uint64_t type, char **buffer, const char **ret) {
+        int r;
+
+        assert(buffer);
+        assert(ret);
+
+        switch (type) {
+
+        case SD_PATH_TEMPORARY:
+                return tmp_dir(ret);
+
+        case SD_PATH_TEMPORARY_LARGE:
+                return var_tmp_dir(ret);
+
+        case SD_PATH_SYSTEM_BINARIES:
+                *ret = "/usr/bin";
+                return 0;
+
+        case SD_PATH_SYSTEM_INCLUDE:
+                *ret = "/usr/include";
+                return 0;
+
+        case SD_PATH_SYSTEM_LIBRARY_PRIVATE:
+                *ret = "/usr/lib";
+                return 0;
+
+        case SD_PATH_SYSTEM_LIBRARY_ARCH:
+                *ret = LIBDIR;
+                return 0;
+
+        case SD_PATH_SYSTEM_SHARED:
+                *ret = "/usr/share";
+                return 0;
+
+        case SD_PATH_SYSTEM_CONFIGURATION_FACTORY:
+                *ret = "/usr/share/factory/etc";
+                return 0;
+
+        case SD_PATH_SYSTEM_STATE_FACTORY:
+                *ret = "/usr/share/factory/var";
+                return 0;
+
+        case SD_PATH_SYSTEM_CONFIGURATION:
+                *ret = "/etc";
+                return 0;
+
+        case SD_PATH_SYSTEM_RUNTIME:
+                *ret = "/run";
+                return 0;
+
+        case SD_PATH_SYSTEM_RUNTIME_LOGS:
+                *ret = "/run/log";
+                return 0;
+
+        case SD_PATH_SYSTEM_STATE_PRIVATE:
+                *ret = "/var/lib";
+                return 0;
+
+        case SD_PATH_SYSTEM_STATE_LOGS:
+                *ret = "/var/log";
+                return 0;
+
+        case SD_PATH_SYSTEM_STATE_CACHE:
+                *ret = "/var/cache";
+                return 0;
+
+        case SD_PATH_SYSTEM_STATE_SPOOL:
+                *ret = "/var/spool";
+                return 0;
+
+        case SD_PATH_USER_BINARIES:
+                return from_home_dir(NULL, ".local/bin", buffer, ret);
+
+        case SD_PATH_USER_LIBRARY_PRIVATE:
+                return from_home_dir(NULL, ".local/lib", buffer, ret);
+
+        case SD_PATH_USER_LIBRARY_ARCH:
+                return from_home_dir(NULL, ".local/lib/" LIB_ARCH_TUPLE, buffer, ret);
+
+        case SD_PATH_USER_SHARED:
+                return from_home_dir("XDG_DATA_HOME", ".local/share", buffer, ret);
+
+        case SD_PATH_USER_CONFIGURATION:
+                return from_home_dir("XDG_CONFIG_HOME", ".config", buffer, ret);
+
+        case SD_PATH_USER_RUNTIME:
+                return from_environment("XDG_RUNTIME_DIR", NULL, ret);
+
+        case SD_PATH_USER_STATE_CACHE:
+                return from_home_dir("XDG_CACHE_HOME", ".cache", buffer, ret);
+
+        case SD_PATH_USER:
+                r = get_home_dir(buffer);
+                if (r < 0)
+                        return r;
+
+                *ret = *buffer;
+                return 0;
+
+        case SD_PATH_USER_DOCUMENTS:
+                return from_user_dir("XDG_DOCUMENTS_DIR", buffer, ret);
+
+        case SD_PATH_USER_MUSIC:
+                return from_user_dir("XDG_MUSIC_DIR", buffer, ret);
+
+        case SD_PATH_USER_PICTURES:
+                return from_user_dir("XDG_PICTURES_DIR", buffer, ret);
+
+        case SD_PATH_USER_VIDEOS:
+                return from_user_dir("XDG_VIDEOS_DIR", buffer, ret);
+
+        case SD_PATH_USER_DOWNLOAD:
+                return from_user_dir("XDG_DOWNLOAD_DIR", buffer, ret);
+
+        case SD_PATH_USER_PUBLIC:
+                return from_user_dir("XDG_PUBLICSHARE_DIR", buffer, ret);
+
+        case SD_PATH_USER_TEMPLATES:
+                return from_user_dir("XDG_TEMPLATES_DIR", buffer, ret);
+
+        case SD_PATH_USER_DESKTOP:
+                return from_user_dir("XDG_DESKTOP_DIR", buffer, ret);
+
+        case SD_PATH_SYSTEMD_UTIL:
+                *ret = ROOTPREFIX_NOSLASH "/lib/systemd";
+                return 0;
+
+        case SD_PATH_SYSTEMD_SYSTEM_UNIT:
+                *ret = SYSTEM_DATA_UNIT_PATH;
+                return 0;
+
+        case SD_PATH_SYSTEMD_SYSTEM_PRESET:
+                *ret = ROOTPREFIX_NOSLASH "/lib/systemd/system-preset";
+                return 0;
+
+        case SD_PATH_SYSTEMD_USER_UNIT:
+                *ret = USER_DATA_UNIT_DIR;
+                return 0;
+
+        case SD_PATH_SYSTEMD_USER_PRESET:
+                *ret = ROOTPREFIX_NOSLASH "/lib/systemd/user-preset";
+                return 0;
+
+        case SD_PATH_SYSTEMD_SYSTEM_CONF:
+                *ret = SYSTEM_CONFIG_UNIT_DIR;
+                return 0;
+
+        case SD_PATH_SYSTEMD_USER_CONF:
+                *ret = USER_CONFIG_UNIT_DIR;
+                return 0;
+
+        case SD_PATH_SYSTEMD_SYSTEM_GENERATOR:
+                *ret = SYSTEM_GENERATOR_DIR;
+                return 0;
+
+        case SD_PATH_SYSTEMD_USER_GENERATOR:
+                *ret = USER_GENERATOR_DIR;
+                return 0;
+
+        case SD_PATH_SYSTEMD_SLEEP:
+                *ret = ROOTPREFIX_NOSLASH "/lib/systemd/system-sleep";
+                return 0;
+
+        case SD_PATH_SYSTEMD_SHUTDOWN:
+                *ret = ROOTPREFIX_NOSLASH "/lib/systemd/system-shutdown";
+                return 0;
+
+        case SD_PATH_TMPFILES:
+                *ret = "/usr/lib/tmpfiles.d";
+                return 0;
+
+        case SD_PATH_SYSUSERS:
+                *ret = ROOTPREFIX_NOSLASH "/lib/sysusers.d";
+                return 0;
+
+        case SD_PATH_SYSCTL:
+                *ret = ROOTPREFIX_NOSLASH "/lib/sysctl.d";
+                return 0;
+
+        case SD_PATH_BINFMT:
+                *ret = ROOTPREFIX_NOSLASH "/lib/binfmt.d";
+                return 0;
+
+        case SD_PATH_MODULES_LOAD:
+                *ret = ROOTPREFIX_NOSLASH "/lib/modules-load.d";
+                return 0;
+
+        case SD_PATH_CATALOG:
+                *ret = "/usr/lib/systemd/catalog";
+                return 0;
+        }
+
+        return -EOPNOTSUPP;
+}
+
+static int get_path_alloc(uint64_t type, const char *suffix, char **path) {
+        _cleanup_free_ char *buffer = NULL;
+        char *buffer2 = NULL;
+        const char *ret;
+        int r;
+
+        assert(path);
+
+        r = get_path(type, &buffer, &ret);
+        if (r < 0)
+                return r;
+
+        if (suffix) {
+                suffix += strspn(suffix, "/");
+                buffer2 = path_join(ret, suffix);
+                if (!buffer2)
+                        return -ENOMEM;
+        } else if (!buffer) {
+                buffer = strdup(ret);
+                if (!buffer)
+                        return -ENOMEM;
+        }
+
+        *path = buffer2 ?: TAKE_PTR(buffer);
+        return 0;
+}
+
+_public_ int sd_path_lookup(uint64_t type, const char *suffix, char **path) {
+        int r;
+
+        assert_return(path, -EINVAL);
+
+        r = get_path_alloc(type, suffix, path);
+        if (r != -EOPNOTSUPP)
+                return r;
+
+        /* Fall back to sd_path_lookup_strv */
+        _cleanup_strv_free_ char **l = NULL;
+        char *buffer;
+
+        r = sd_path_lookup_strv(type, suffix, &l);
+        if (r < 0)
+                return r;
+
+        buffer = strv_join(l, ":");
+        if (!buffer)
+                return -ENOMEM;
+
+        *path = buffer;
+        return 0;
+}
+
+static int search_from_environment(
+                char ***list,
+                const char *env_home,
+                const char *home_suffix,
+                const char *env_search,
+                bool env_search_sufficient,
+                const char *first, ...) {
+
+        _cleanup_strv_free_ char **l = NULL;
+        const char *e;
+        char *h = NULL;
+        int r;
+
+        assert(list);
+
+        if (env_search) {
+                e = secure_getenv(env_search);
+                if (e) {
+                        l = strv_split(e, ":");
+                        if (!l)
+                                return -ENOMEM;
+
+                        if (env_search_sufficient) {
+                                *list = TAKE_PTR(l);
+                                return 0;
+                        }
+                }
+        }
+
+        if (!l && first) {
+                va_list ap;
+
+                va_start(ap, first);
+                l = strv_new_ap(first, ap);
+                va_end(ap);
+
+                if (!l)
+                        return -ENOMEM;
+        }
+
+        if (env_home) {
+                e = secure_getenv(env_home);
+                if (e && path_is_absolute(e)) {
+                        h = strdup(e);
+                        if (!h)
+                                return -ENOMEM;
+                }
+        }
+
+        if (!h && home_suffix) {
+                e = secure_getenv("HOME");
+                if (e && path_is_absolute(e)) {
+                        h = path_join(e, home_suffix);
+                        if (!h)
+                                return -ENOMEM;
+                }
+        }
+
+        if (h) {
+                r = strv_consume_prepend(&l, h);
+                if (r < 0)
+                        return -ENOMEM;
+        }
+
+        *list = TAKE_PTR(l);
+        return 0;
+}
+
+#if HAVE_SPLIT_BIN
+#  define ARRAY_SBIN_BIN(x) x "sbin", x "bin"
+#else
+#  define ARRAY_SBIN_BIN(x) x "bin"
+#endif
+
+static int get_search(uint64_t type, char ***list) {
+        int r;
+
+        assert(list);
+
+        switch(type) {
+
+        case SD_PATH_SEARCH_BINARIES:
+                return search_from_environment(list,
+                                               NULL,
+                                               ".local/bin",
+                                               "PATH",
+                                               true,
+                                               ARRAY_SBIN_BIN("/usr/local/"),
+                                               ARRAY_SBIN_BIN("/usr/"),
+#if HAVE_SPLIT_USR
+                                               ARRAY_SBIN_BIN("/"),
+#endif
+                                               NULL);
+
+        case SD_PATH_SEARCH_LIBRARY_PRIVATE:
+                return search_from_environment(list,
+                                               NULL,
+                                               ".local/lib",
+                                               NULL,
+                                               false,
+                                               "/usr/local/lib",
+                                               "/usr/lib",
+#if HAVE_SPLIT_USR
+                                               "/lib",
+#endif
+                                               NULL);
+
+        case SD_PATH_SEARCH_LIBRARY_ARCH:
+                return search_from_environment(list,
+                                               NULL,
+                                               ".local/lib/" LIB_ARCH_TUPLE,
+                                               "LD_LIBRARY_PATH",
+                                               true,
+                                               LIBDIR,
+#if HAVE_SPLIT_USR
+                                               ROOTLIBDIR,
+#endif
+                                               NULL);
+
+        case SD_PATH_SEARCH_SHARED:
+                return search_from_environment(list,
+                                               "XDG_DATA_HOME",
+                                               ".local/share",
+                                               "XDG_DATA_DIRS",
+                                               false,
+                                               "/usr/local/share",
+                                               "/usr/share",
+                                               NULL);
+
+        case SD_PATH_SEARCH_CONFIGURATION_FACTORY:
+                return search_from_environment(list,
+                                               NULL,
+                                               NULL,
+                                               NULL,
+                                               false,
+                                               "/usr/local/share/factory/etc",
+                                               "/usr/share/factory/etc",
+                                               NULL);
+
+        case SD_PATH_SEARCH_STATE_FACTORY:
+                return search_from_environment(list,
+                                               NULL,
+                                               NULL,
+                                               NULL,
+                                               false,
+                                               "/usr/local/share/factory/var",
+                                               "/usr/share/factory/var",
+                                               NULL);
+
+        case SD_PATH_SEARCH_CONFIGURATION:
+                return search_from_environment(list,
+                                               "XDG_CONFIG_HOME",
+                                               ".config",
+                                               "XDG_CONFIG_DIRS",
+                                               false,
+                                               "/etc",
+                                               NULL);
+
+        case SD_PATH_SEARCH_BINARIES_DEFAULT:
+                return strv_from_nulstr(list, DEFAULT_PATH_NULSTR);
+
+        case SD_PATH_SYSTEMD_SEARCH_SYSTEM_UNIT:
+        case SD_PATH_SYSTEMD_SEARCH_USER_UNIT: {
+                _cleanup_(lookup_paths_free) LookupPaths lp = {};
+                const UnitFileScope scope = type == SD_PATH_SYSTEMD_SEARCH_SYSTEM_UNIT ?
+                                                    UNIT_FILE_SYSTEM : UNIT_FILE_USER;
+
+                r = lookup_paths_init(&lp, scope, 0, NULL);
+                if (r < 0)
+                        return r;
+
+                *list = TAKE_PTR(lp.search_path);
+                return 0;
+        }
+
+        case SD_PATH_SYSTEMD_SEARCH_SYSTEM_GENERATOR:
+        case SD_PATH_SYSTEMD_SEARCH_USER_GENERATOR: {
+                char **t;
+                const UnitFileScope scope = type == SD_PATH_SYSTEMD_SEARCH_SYSTEM_GENERATOR ?
+                                                    UNIT_FILE_SYSTEM : UNIT_FILE_USER;
+
+                t = generator_binary_paths(scope);
+                if (!t)
+                        return -ENOMEM;
+
+                *list = t;
+                return 0;
+        }
+
+        case SD_PATH_SYSTEMD_SEARCH_NETWORK:
+                return strv_from_nulstr(list, NETWORK_DIRS_NULSTR);
+
+        }
+
+        return -EOPNOTSUPP;
+}
+
+_public_ int sd_path_lookup_strv(uint64_t type, const char *suffix, char ***paths) {
+        _cleanup_strv_free_ char **l = NULL, **n = NULL;
+        int r;
+
+        assert_return(paths, -EINVAL);
+
+        r = get_search(type, &l);
+        if (r == -EOPNOTSUPP) {
+                _cleanup_free_ char *t = NULL;
+
+                r = get_path_alloc(type, suffix, &t);
+                if (r < 0)
+                        return r;
+
+                l = new(char*, 2);
+                if (!l)
+                        return -ENOMEM;
+                l[0] = TAKE_PTR(t);
+                l[1] = NULL;
+
+                *paths = TAKE_PTR(l);
+                return 0;
+
+        } else if (r < 0)
+                return r;
+
+        if (!suffix) {
+                *paths = TAKE_PTR(l);
+                return 0;
+        }
+
+        n = new(char*, strv_length(l)+1);
+        if (!n)
+                return -ENOMEM;
+
+        char **i, **j = n;
+        STRV_FOREACH(i, l) {
+                *j = path_join(*i, suffix);
+                if (!*j)
+                        return -ENOMEM;
+
+                j++;
+        }
+        *j = NULL;
+
+        *paths = TAKE_PTR(n);
+        return 0;
+}
diff --git a/src/libsystemd/sd-resolve/resolve-private.h b/src/libsystemd/sd-resolve/resolve-private.h
new file mode 100644
index 0000000..7a339f7
--- /dev/null
+++ b/src/libsystemd/sd-resolve/resolve-private.h
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-resolve.h"
+
+int resolve_getaddrinfo_with_destroy_callback(
+                sd_resolve *resolve, sd_resolve_query **q,
+                const char *node, const char *service, const struct addrinfo *hints,
+                sd_resolve_getaddrinfo_handler_t callback,
+                sd_resolve_destroy_t destroy_callback, void *userdata);
+int resolve_getnameinfo_with_destroy_callback(
+                sd_resolve *resolve, sd_resolve_query **q,
+                const struct sockaddr *sa, socklen_t salen, int flags, uint64_t get,
+                sd_resolve_getnameinfo_handler_t callback,
+                sd_resolve_destroy_t destroy_callback, void *userdata);
+
+#define resolve_getaddrinfo(resolve, ret_query, node, service, hints, callback, destroy_callback, userdata) \
+        ({                                                              \
+                int (*_callback_)(sd_resolve_query*, int, const struct addrinfo*, typeof(userdata)) = callback; \
+                void (*_destroy_)(typeof(userdata)) = destroy_callback; \
+                resolve_getaddrinfo_with_destroy_callback(              \
+                        resolve, ret_query,                             \
+                        node, service, hints,                           \
+                        (sd_resolve_getaddrinfo_handler_t) _callback_,  \
+                        (sd_resolve_destroy_t) _destroy_,               \
+                        userdata);                                      \
+        })
+
+#define resolve_getnameinfo(resolve, ret_query, sa, salen, flags, get, callback, destroy_callback, userdata) \
+        ({                                                              \
+                int (*_callback_)(sd_resolve_query*, int, const char*, const char*, typeof(userdata)) = callback; \
+                void (*_destroy_)(typeof(userdata)) = destroy_callback; \
+                resolve_getaddrinfo_with_destroy_callback(              \
+                        resolve, ret_query,                             \
+                        sa, salen, flags, get,                          \
+                        (sd_resolve_getnameinfo_handler_t) _callback_,  \
+                        (sd_resolve_destroy_t) _destroy_,               \
+                        userdata);                                      \
+        })
diff --git a/src/libsystemd/sd-resolve/sd-resolve.c b/src/libsystemd/sd-resolve/sd-resolve.c
new file mode 100644
index 0000000..2cfa22d
--- /dev/null
+++ b/src/libsystemd/sd-resolve/sd-resolve.c
@@ -0,0 +1,1301 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <poll.h>
+#include <pthread.h>
+#include <resolv.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+
+#include "sd-resolve.h"
+
+#include "alloc-util.h"
+#include "dns-domain.h"
+#include "errno-util.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "list.h"
+#include "memory-util.h"
+#include "missing_syscall.h"
+#include "process-util.h"
+#include "resolve-private.h"
+#include "socket-util.h"
+
+#define WORKERS_MIN 1U
+#define WORKERS_MAX 16U
+#define QUERIES_MAX 256U
+#define BUFSIZE 10240U
+
+typedef enum {
+        REQUEST_ADDRINFO,
+        RESPONSE_ADDRINFO,
+        REQUEST_NAMEINFO,
+        RESPONSE_NAMEINFO,
+        REQUEST_TERMINATE,
+        RESPONSE_DIED
+} QueryType;
+
+enum {
+        REQUEST_RECV_FD,
+        REQUEST_SEND_FD,
+        RESPONSE_RECV_FD,
+        RESPONSE_SEND_FD,
+        _FD_MAX
+};
+
+struct sd_resolve {
+        unsigned n_ref;
+
+        bool dead:1;
+        pid_t original_pid;
+
+        int fds[_FD_MAX];
+
+        pthread_t workers[WORKERS_MAX];
+        unsigned n_valid_workers;
+
+        unsigned current_id;
+        sd_resolve_query* query_array[QUERIES_MAX];
+        unsigned n_queries, n_done, n_outstanding;
+
+        sd_event_source *event_source;
+        sd_event *event;
+
+        sd_resolve_query *current;
+
+        sd_resolve **default_resolve_ptr;
+        pid_t tid;
+
+        LIST_HEAD(sd_resolve_query, queries);
+};
+
+struct sd_resolve_query {
+        unsigned n_ref;
+
+        sd_resolve *resolve;
+
+        QueryType type:4;
+        bool done:1;
+        bool floating:1;
+        unsigned id;
+
+        int ret;
+        int _errno;
+        int _h_errno;
+        struct addrinfo *addrinfo;
+        char *serv, *host;
+
+        union {
+                sd_resolve_getaddrinfo_handler_t getaddrinfo_handler;
+                sd_resolve_getnameinfo_handler_t getnameinfo_handler;
+        };
+
+        void *userdata;
+        sd_resolve_destroy_t destroy_callback;
+
+        LIST_FIELDS(sd_resolve_query, queries);
+};
+
+typedef struct RHeader {
+        QueryType type;
+        unsigned id;
+        size_t length;
+} RHeader;
+
+typedef struct AddrInfoRequest {
+        struct RHeader header;
+        bool hints_valid;
+        int ai_flags;
+        int ai_family;
+        int ai_socktype;
+        int ai_protocol;
+        size_t node_len, service_len;
+} AddrInfoRequest;
+
+typedef struct AddrInfoResponse {
+        struct RHeader header;
+        int ret;
+        int _errno;
+        int _h_errno;
+        /* followed by addrinfo_serialization[] */
+} AddrInfoResponse;
+
+typedef struct AddrInfoSerialization {
+        int ai_flags;
+        int ai_family;
+        int ai_socktype;
+        int ai_protocol;
+        size_t ai_addrlen;
+        size_t canonname_len;
+        /* Followed by ai_addr amd ai_canonname with variable lengths */
+} AddrInfoSerialization;
+
+typedef struct NameInfoRequest {
+        struct RHeader header;
+        int flags;
+        socklen_t sockaddr_len;
+        bool gethost:1, getserv:1;
+} NameInfoRequest;
+
+typedef struct NameInfoResponse {
+        struct RHeader header;
+        size_t hostlen, servlen;
+        int ret;
+        int _errno;
+        int _h_errno;
+} NameInfoResponse;
+
+typedef union Packet {
+        RHeader rheader;
+        AddrInfoRequest addrinfo_request;
+        AddrInfoResponse addrinfo_response;
+        NameInfoRequest nameinfo_request;
+        NameInfoResponse nameinfo_response;
+} Packet;
+
+static int getaddrinfo_done(sd_resolve_query* q);
+static int getnameinfo_done(sd_resolve_query *q);
+
+static void resolve_query_disconnect(sd_resolve_query *q);
+
+#define RESOLVE_DONT_DESTROY(resolve) \
+        _cleanup_(sd_resolve_unrefp) _unused_ sd_resolve *_dont_destroy_##resolve = sd_resolve_ref(resolve)
+
+static void query_assign_errno(sd_resolve_query *q, int ret, int error, int h_error) {
+        assert(q);
+
+        q->ret = ret;
+        q->_errno = abs(error);
+        q->_h_errno = h_error;
+}
+
+static int send_died(int out_fd) {
+        RHeader rh = {
+                .type = RESPONSE_DIED,
+                .length = sizeof(RHeader),
+        };
+
+        assert(out_fd >= 0);
+
+        if (send(out_fd, &rh, rh.length, MSG_NOSIGNAL) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static void *serialize_addrinfo(void *p, const struct addrinfo *ai, size_t *length, size_t maxlength) {
+        AddrInfoSerialization s;
+        size_t cnl, l;
+
+        assert(p);
+        assert(ai);
+        assert(length);
+        assert(*length <= maxlength);
+
+        cnl = ai->ai_canonname ? strlen(ai->ai_canonname)+1 : 0;
+        l = sizeof(AddrInfoSerialization) + ai->ai_addrlen + cnl;
+
+        if (*length + l > maxlength)
+                return NULL;
+
+        s = (AddrInfoSerialization) {
+                .ai_flags = ai->ai_flags,
+                .ai_family = ai->ai_family,
+                .ai_socktype = ai->ai_socktype,
+                .ai_protocol = ai->ai_protocol,
+                .ai_addrlen = ai->ai_addrlen,
+                .canonname_len = cnl,
+        };
+
+        memcpy((uint8_t*) p, &s, sizeof(AddrInfoSerialization));
+        memcpy((uint8_t*) p + sizeof(AddrInfoSerialization), ai->ai_addr, ai->ai_addrlen);
+        memcpy_safe((char*) p + sizeof(AddrInfoSerialization) + ai->ai_addrlen,
+                    ai->ai_canonname, cnl);
+
+        *length += l;
+        return (uint8_t*) p + l;
+}
+
+static int send_addrinfo_reply(
+                int out_fd,
+                unsigned id,
+                int ret,
+                struct addrinfo *ai,
+                int _errno,
+                int _h_errno) {
+
+        AddrInfoResponse resp = {};
+        union {
+                AddrInfoSerialization ais;
+                uint8_t space[BUFSIZE];
+        } buffer;
+        struct iovec iov[2];
+        struct msghdr mh;
+
+        assert(out_fd >= 0);
+
+        resp = (AddrInfoResponse) {
+                .header.type = RESPONSE_ADDRINFO,
+                .header.id = id,
+                .header.length = sizeof(AddrInfoResponse),
+                .ret = ret,
+                ._errno = _errno,
+                ._h_errno = _h_errno,
+        };
+
+        msan_unpoison(&resp, sizeof(resp));
+
+        if (ret == 0 && ai) {
+                void *p = &buffer;
+                struct addrinfo *k;
+
+                for (k = ai; k; k = k->ai_next) {
+                        p = serialize_addrinfo(p, k, &resp.header.length, (uint8_t*) &buffer + BUFSIZE - (uint8_t*) p);
+                        if (!p) {
+                                freeaddrinfo(ai);
+                                return -ENOBUFS;
+                        }
+                }
+        }
+
+        if (ai)
+                freeaddrinfo(ai);
+
+        iov[0] = IOVEC_MAKE(&resp, sizeof(AddrInfoResponse));
+        iov[1] = IOVEC_MAKE(&buffer, resp.header.length - sizeof(AddrInfoResponse));
+
+        mh = (struct msghdr) {
+                .msg_iov = iov,
+                .msg_iovlen = ELEMENTSOF(iov)
+        };
+
+        if (sendmsg(out_fd, &mh, MSG_NOSIGNAL) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int send_nameinfo_reply(
+                int out_fd,
+                unsigned id,
+                int ret,
+                const char *host,
+                const char *serv,
+                int _errno,
+                int _h_errno) {
+
+        NameInfoResponse resp = {};
+        struct iovec iov[3];
+        struct msghdr mh;
+        size_t hl, sl;
+
+        assert(out_fd >= 0);
+
+        sl = serv ? strlen(serv)+1 : 0;
+        hl = host ? strlen(host)+1 : 0;
+
+        resp = (NameInfoResponse) {
+                .header.type = RESPONSE_NAMEINFO,
+                .header.id = id,
+                .header.length = sizeof(NameInfoResponse) + hl + sl,
+                .hostlen = hl,
+                .servlen = sl,
+                .ret = ret,
+                ._errno = _errno,
+                ._h_errno = _h_errno,
+        };
+
+        msan_unpoison(&resp, sizeof(resp));
+
+        iov[0] = IOVEC_MAKE(&resp, sizeof(NameInfoResponse));
+        iov[1] = IOVEC_MAKE((void*) host, hl);
+        iov[2] = IOVEC_MAKE((void*) serv, sl);
+
+        mh = (struct msghdr) {
+                .msg_iov = iov,
+                .msg_iovlen = ELEMENTSOF(iov)
+        };
+
+        if (sendmsg(out_fd, &mh, MSG_NOSIGNAL) < 0)
+                return -errno;
+
+        return 0;
+}
+
+static int handle_request(int out_fd, const Packet *packet, size_t length) {
+        const RHeader *req;
+
+        assert(out_fd >= 0);
+        assert(packet);
+
+        req = &packet->rheader;
+
+        assert_return(length >= sizeof(RHeader), -EIO);
+        assert_return(length == req->length, -EIO);
+
+        switch (req->type) {
+
+        case REQUEST_ADDRINFO: {
+               const AddrInfoRequest *ai_req = &packet->addrinfo_request;
+               struct addrinfo hints, *result = NULL;
+               const char *node, *service;
+               int ret;
+
+               assert_return(length >= sizeof(AddrInfoRequest), -EBADMSG);
+               assert_return(length == sizeof(AddrInfoRequest) + ai_req->node_len + ai_req->service_len, -EBADMSG);
+
+               hints = (struct addrinfo) {
+                       .ai_flags = ai_req->ai_flags,
+                       .ai_family = ai_req->ai_family,
+                       .ai_socktype = ai_req->ai_socktype,
+                       .ai_protocol = ai_req->ai_protocol,
+               };
+
+               msan_unpoison(&hints, sizeof(hints));
+
+               node = ai_req->node_len ? (const char*) ai_req + sizeof(AddrInfoRequest) : NULL;
+               service = ai_req->service_len ? (const char*) ai_req + sizeof(AddrInfoRequest) + ai_req->node_len : NULL;
+
+               ret = getaddrinfo(node, service,
+                                 ai_req->hints_valid ? &hints : NULL,
+                                 &result);
+
+               /* send_addrinfo_reply() frees result */
+               return send_addrinfo_reply(out_fd, req->id, ret, result, errno, h_errno);
+        }
+
+        case REQUEST_NAMEINFO: {
+               const NameInfoRequest *ni_req = &packet->nameinfo_request;
+               char hostbuf[NI_MAXHOST], servbuf[NI_MAXSERV];
+               union sockaddr_union sa;
+               int ret;
+
+               assert_return(length >= sizeof(NameInfoRequest), -EBADMSG);
+               assert_return(length == sizeof(NameInfoRequest) + ni_req->sockaddr_len, -EBADMSG);
+               assert_return(ni_req->sockaddr_len <= sizeof(sa), -EBADMSG);
+
+               memcpy(&sa, (const uint8_t *) ni_req + sizeof(NameInfoRequest), ni_req->sockaddr_len);
+
+               ret = getnameinfo(&sa.sa, ni_req->sockaddr_len,
+                                 ni_req->gethost ? hostbuf : NULL, ni_req->gethost ? sizeof(hostbuf) : 0,
+                                 ni_req->getserv ? servbuf : NULL, ni_req->getserv ? sizeof(servbuf) : 0,
+                                 ni_req->flags);
+
+               return send_nameinfo_reply(out_fd, req->id, ret,
+                                          ret == 0 && ni_req->gethost ? hostbuf : NULL,
+                                          ret == 0 && ni_req->getserv ? servbuf : NULL,
+                                          errno, h_errno);
+        }
+
+        case REQUEST_TERMINATE:
+                 /* Quit */
+                 return -ECONNRESET;
+
+        default:
+                assert_not_reached("Unknown request");
+        }
+
+        return 0;
+}
+
+static void* thread_worker(void *p) {
+        sd_resolve *resolve = p;
+
+        /* Assign a pretty name to this thread */
+        (void) pthread_setname_np(pthread_self(), "sd-resolve");
+
+        while (!resolve->dead) {
+                union {
+                        Packet packet;
+                        uint8_t space[BUFSIZE];
+                } buf;
+                ssize_t length;
+
+                length = recv(resolve->fds[REQUEST_RECV_FD], &buf, sizeof buf, 0);
+                if (length < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        break;
+                }
+                if (length == 0)
+                        break;
+
+                if (handle_request(resolve->fds[RESPONSE_SEND_FD], &buf.packet, (size_t) length) < 0)
+                        break;
+        }
+
+        send_died(resolve->fds[RESPONSE_SEND_FD]);
+
+        return NULL;
+}
+
+static int start_threads(sd_resolve *resolve, unsigned extra) {
+        sigset_t ss, saved_ss;
+        unsigned n;
+        int r, k;
+
+        assert_se(sigfillset(&ss) >= 0);
+
+        /* No signals in forked off threads please. We set the mask before forking, so that the threads never exist
+         * with a different mask than a fully blocked one */
+        r = pthread_sigmask(SIG_BLOCK, &ss, &saved_ss);
+        if (r > 0)
+                return -r;
+
+        n = resolve->n_outstanding + extra;
+        n = CLAMP(n, WORKERS_MIN, WORKERS_MAX);
+
+        while (resolve->n_valid_workers < n) {
+                r = pthread_create(&resolve->workers[resolve->n_valid_workers], NULL, thread_worker, resolve);
+                if (r > 0) {
+                        r = -r;
+                        goto finish;
+                }
+
+                resolve->n_valid_workers++;
+        }
+
+        r = 0;
+
+finish:
+        k = pthread_sigmask(SIG_SETMASK, &saved_ss, NULL);
+        if (k > 0 && r >= 0)
+                r = -k;
+
+        return r;
+}
+
+static bool resolve_pid_changed(sd_resolve *r) {
+        assert(r);
+
+        /* We don't support people creating a resolver and keeping it
+         * around after fork(). Let's complain. */
+
+        return r->original_pid != getpid_cached();
+}
+
+_public_ int sd_resolve_new(sd_resolve **ret) {
+        _cleanup_(sd_resolve_unrefp) sd_resolve *resolve = NULL;
+        int i;
+
+        assert_return(ret, -EINVAL);
+
+        resolve = new0(sd_resolve, 1);
+        if (!resolve)
+                return -ENOMEM;
+
+        resolve->n_ref = 1;
+        resolve->original_pid = getpid_cached();
+
+        for (i = 0; i < _FD_MAX; i++)
+                resolve->fds[i] = -1;
+
+        if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, resolve->fds + REQUEST_RECV_FD) < 0)
+                return -errno;
+
+        if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, resolve->fds + RESPONSE_RECV_FD) < 0)
+                return -errno;
+
+        for (i = 0; i < _FD_MAX; i++)
+                resolve->fds[i] = fd_move_above_stdio(resolve->fds[i]);
+
+        (void) fd_inc_sndbuf(resolve->fds[REQUEST_SEND_FD], QUERIES_MAX * BUFSIZE);
+        (void) fd_inc_rcvbuf(resolve->fds[REQUEST_RECV_FD], QUERIES_MAX * BUFSIZE);
+        (void) fd_inc_sndbuf(resolve->fds[RESPONSE_SEND_FD], QUERIES_MAX * BUFSIZE);
+        (void) fd_inc_rcvbuf(resolve->fds[RESPONSE_RECV_FD], QUERIES_MAX * BUFSIZE);
+
+        (void) fd_nonblock(resolve->fds[RESPONSE_RECV_FD], true);
+
+        *ret = TAKE_PTR(resolve);
+        return 0;
+}
+
+_public_ int sd_resolve_default(sd_resolve **ret) {
+        static thread_local sd_resolve *default_resolve = NULL;
+        sd_resolve *e = NULL;
+        int r;
+
+        if (!ret)
+                return !!default_resolve;
+
+        if (default_resolve) {
+                *ret = sd_resolve_ref(default_resolve);
+                return 0;
+        }
+
+        r = sd_resolve_new(&e);
+        if (r < 0)
+                return r;
+
+        e->default_resolve_ptr = &default_resolve;
+        e->tid = gettid();
+        default_resolve = e;
+
+        *ret = e;
+        return 1;
+}
+
+_public_ int sd_resolve_get_tid(sd_resolve *resolve, pid_t *tid) {
+        assert_return(resolve, -EINVAL);
+        assert_return(tid, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        if (resolve->tid != 0) {
+                *tid = resolve->tid;
+                return 0;
+        }
+
+        if (resolve->event)
+                return sd_event_get_tid(resolve->event, tid);
+
+        return -ENXIO;
+}
+
+static sd_resolve *resolve_free(sd_resolve *resolve) {
+        PROTECT_ERRNO;
+        sd_resolve_query *q;
+        unsigned i;
+
+        assert(resolve);
+
+        while ((q = resolve->queries)) {
+                assert(q->floating);
+                resolve_query_disconnect(q);
+                sd_resolve_query_unref(q);
+        }
+
+        if (resolve->default_resolve_ptr)
+                *(resolve->default_resolve_ptr) = NULL;
+
+        resolve->dead = true;
+
+        sd_resolve_detach_event(resolve);
+
+        if (resolve->fds[REQUEST_SEND_FD] >= 0) {
+
+                RHeader req = {
+                        .type = REQUEST_TERMINATE,
+                        .length = sizeof req,
+                };
+
+                /* Send one termination packet for each worker */
+                for (i = 0; i < resolve->n_valid_workers; i++)
+                        (void) send(resolve->fds[REQUEST_SEND_FD], &req, req.length, MSG_NOSIGNAL);
+        }
+
+        /* Now terminate them and wait until they are gone.
+           If we get an error than most likely the thread already exited. */
+        for (i = 0; i < resolve->n_valid_workers; i++)
+                (void) pthread_join(resolve->workers[i], NULL);
+
+        /* Close all communication channels */
+        close_many(resolve->fds, _FD_MAX);
+
+        return mfree(resolve);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_resolve, sd_resolve, resolve_free);
+
+_public_ int sd_resolve_get_fd(sd_resolve *resolve) {
+        assert_return(resolve, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        return resolve->fds[RESPONSE_RECV_FD];
+}
+
+_public_ int sd_resolve_get_events(sd_resolve *resolve) {
+        assert_return(resolve, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        return resolve->n_queries > resolve->n_done ? POLLIN : 0;
+}
+
+_public_ int sd_resolve_get_timeout(sd_resolve *resolve, uint64_t *usec) {
+        assert_return(resolve, -EINVAL);
+        assert_return(usec, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        *usec = (uint64_t) -1;
+        return 0;
+}
+
+static sd_resolve_query *lookup_query(sd_resolve *resolve, unsigned id) {
+        sd_resolve_query *q;
+
+        assert(resolve);
+
+        q = resolve->query_array[id % QUERIES_MAX];
+        if (q)
+                if (q->id == id)
+                        return q;
+
+        return NULL;
+}
+
+static int complete_query(sd_resolve *resolve, sd_resolve_query *q) {
+        int r;
+
+        assert(q);
+        assert(!q->done);
+        assert(q->resolve == resolve);
+
+        q->done = true;
+        resolve->n_done++;
+
+        resolve->current = sd_resolve_query_ref(q);
+
+        switch (q->type) {
+
+        case REQUEST_ADDRINFO:
+                r = getaddrinfo_done(q);
+                break;
+
+        case REQUEST_NAMEINFO:
+                r = getnameinfo_done(q);
+                break;
+
+        default:
+                assert_not_reached("Cannot complete unknown query type");
+        }
+
+        resolve->current = NULL;
+
+        if (q->floating) {
+                resolve_query_disconnect(q);
+                sd_resolve_query_unref(q);
+        }
+
+        sd_resolve_query_unref(q);
+
+        return r;
+}
+
+static int unserialize_addrinfo(const void **p, size_t *length, struct addrinfo **ret_ai) {
+        AddrInfoSerialization s;
+        struct addrinfo *ai;
+        size_t l;
+
+        assert(p);
+        assert(*p);
+        assert(ret_ai);
+        assert(length);
+
+        if (*length < sizeof(AddrInfoSerialization))
+                return -EBADMSG;
+
+        memcpy(&s, *p, sizeof(s));
+
+        l = sizeof(AddrInfoSerialization) + s.ai_addrlen + s.canonname_len;
+        if (*length < l)
+                return -EBADMSG;
+
+        ai = new(struct addrinfo, 1);
+        if (!ai)
+                return -ENOMEM;
+
+        *ai = (struct addrinfo) {
+                .ai_flags = s.ai_flags,
+                .ai_family = s.ai_family,
+                .ai_socktype = s.ai_socktype,
+                .ai_protocol = s.ai_protocol,
+                .ai_addrlen = s.ai_addrlen,
+        };
+
+        if (s.ai_addrlen > 0) {
+                ai->ai_addr = memdup((const uint8_t*) *p + sizeof(AddrInfoSerialization), s.ai_addrlen);
+                if (!ai->ai_addr) {
+                        free(ai);
+                        return -ENOMEM;
+                }
+        }
+
+        if (s.canonname_len > 0) {
+                ai->ai_canonname = memdup((const uint8_t*) *p + sizeof(AddrInfoSerialization) + s.ai_addrlen, s.canonname_len);
+                if (!ai->ai_canonname) {
+                        free(ai->ai_addr);
+                        free(ai);
+                        return -ENOMEM;
+                }
+        }
+
+        *length -= l;
+        *ret_ai = ai;
+        *p = ((const uint8_t*) *p) + l;
+
+        return 0;
+}
+
+static int handle_response(sd_resolve *resolve, const Packet *packet, size_t length) {
+        const RHeader *resp;
+        sd_resolve_query *q;
+        int r;
+
+        assert(resolve);
+        assert(packet);
+
+        resp = &packet->rheader;
+        assert_return(length >= sizeof(RHeader), -EIO);
+        assert_return(length == resp->length, -EIO);
+
+        if (resp->type == RESPONSE_DIED) {
+                resolve->dead = true;
+                return 0;
+        }
+
+        assert(resolve->n_outstanding > 0);
+        resolve->n_outstanding--;
+
+        q = lookup_query(resolve, resp->id);
+        if (!q)
+                return 0;
+
+        switch (resp->type) {
+
+        case RESPONSE_ADDRINFO: {
+                const AddrInfoResponse *ai_resp = &packet->addrinfo_response;
+                const void *p;
+                size_t l;
+                struct addrinfo *prev = NULL;
+
+                assert_return(length >= sizeof(AddrInfoResponse), -EBADMSG);
+                assert_return(q->type == REQUEST_ADDRINFO, -EBADMSG);
+
+                query_assign_errno(q, ai_resp->ret, ai_resp->_errno, ai_resp->_h_errno);
+
+                l = length - sizeof(AddrInfoResponse);
+                p = (const uint8_t*) resp + sizeof(AddrInfoResponse);
+
+                while (l > 0 && p) {
+                        struct addrinfo *ai = NULL;
+
+                        r = unserialize_addrinfo(&p, &l, &ai);
+                        if (r < 0) {
+                                query_assign_errno(q, EAI_SYSTEM, r, 0);
+                                freeaddrinfo(q->addrinfo);
+                                q->addrinfo = NULL;
+                                break;
+                        }
+
+                        if (prev)
+                                prev->ai_next = ai;
+                        else
+                                q->addrinfo = ai;
+
+                        prev = ai;
+                }
+
+                return complete_query(resolve, q);
+        }
+
+        case RESPONSE_NAMEINFO: {
+                const NameInfoResponse *ni_resp = &packet->nameinfo_response;
+
+                assert_return(length >= sizeof(NameInfoResponse), -EBADMSG);
+                assert_return(q->type == REQUEST_NAMEINFO, -EBADMSG);
+
+                if (ni_resp->hostlen > DNS_HOSTNAME_MAX ||
+                    ni_resp->servlen > DNS_HOSTNAME_MAX ||
+                    sizeof(NameInfoResponse) + ni_resp->hostlen + ni_resp->servlen > length)
+                        query_assign_errno(q, EAI_SYSTEM, EIO, 0);
+                else {
+                        query_assign_errno(q, ni_resp->ret, ni_resp->_errno, ni_resp->_h_errno);
+
+                        if (ni_resp->hostlen > 0) {
+                                q->host = strndup((const char*) ni_resp + sizeof(NameInfoResponse),
+                                                  ni_resp->hostlen-1);
+                                if (!q->host)
+                                        query_assign_errno(q, EAI_MEMORY, ENOMEM, 0);
+                        }
+
+                        if (ni_resp->servlen > 0) {
+                                q->serv = strndup((const char*) ni_resp + sizeof(NameInfoResponse) + ni_resp->hostlen,
+                                                  ni_resp->servlen-1);
+                                if (!q->serv)
+                                        query_assign_errno(q, EAI_MEMORY, ENOMEM, 0);
+                        }
+                }
+
+                return complete_query(resolve, q);
+        }
+
+        default:
+                return 0;
+        }
+}
+
+_public_ int sd_resolve_process(sd_resolve *resolve) {
+        RESOLVE_DONT_DESTROY(resolve);
+
+        union {
+                Packet packet;
+                uint8_t space[BUFSIZE];
+        } buf;
+        ssize_t l;
+        int r;
+
+        assert_return(resolve, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        /* We don't allow recursively invoking sd_resolve_process(). */
+        assert_return(!resolve->current, -EBUSY);
+
+        l = recv(resolve->fds[RESPONSE_RECV_FD], &buf, sizeof buf, 0);
+        if (l < 0) {
+                if (errno == EAGAIN)
+                        return 0;
+
+                return -errno;
+        }
+        if (l == 0)
+                return -ECONNREFUSED;
+
+        r = handle_response(resolve, &buf.packet, (size_t) l);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+_public_ int sd_resolve_wait(sd_resolve *resolve, uint64_t timeout_usec) {
+        int r;
+
+        assert_return(resolve, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        if (resolve->n_done >= resolve->n_queries)
+                return 0;
+
+        do {
+                r = fd_wait_for_event(resolve->fds[RESPONSE_RECV_FD], POLLIN, timeout_usec);
+        } while (r == -EINTR);
+
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ETIMEDOUT;
+
+        return sd_resolve_process(resolve);
+}
+
+static int alloc_query(sd_resolve *resolve, bool floating, sd_resolve_query **_q) {
+        sd_resolve_query *q;
+        int r;
+
+        assert(resolve);
+        assert(_q);
+
+        if (resolve->n_queries >= QUERIES_MAX)
+                return -ENOBUFS;
+
+        r = start_threads(resolve, 1);
+        if (r < 0)
+                return r;
+
+        while (resolve->query_array[resolve->current_id % QUERIES_MAX])
+                resolve->current_id++;
+
+        q = resolve->query_array[resolve->current_id % QUERIES_MAX] = new0(sd_resolve_query, 1);
+        if (!q)
+                return -ENOMEM;
+
+        q->n_ref = 1;
+        q->resolve = resolve;
+        q->floating = floating;
+        q->id = resolve->current_id++;
+
+        if (!floating)
+                sd_resolve_ref(resolve);
+
+        LIST_PREPEND(queries, resolve->queries, q);
+        resolve->n_queries++;
+
+        *_q = q;
+        return 0;
+}
+
+int resolve_getaddrinfo_with_destroy_callback(
+                sd_resolve *resolve,
+                sd_resolve_query **ret_query,
+                const char *node, const char *service,
+                const struct addrinfo *hints,
+                sd_resolve_getaddrinfo_handler_t callback,
+                sd_resolve_destroy_t destroy_callback,
+                void *userdata) {
+
+        _cleanup_(sd_resolve_query_unrefp) sd_resolve_query *q = NULL;
+        size_t node_len, service_len;
+        AddrInfoRequest req = {};
+        struct iovec iov[3];
+        struct msghdr mh = {};
+        int r;
+
+        assert_return(resolve, -EINVAL);
+        assert_return(node || service, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        r = alloc_query(resolve, !ret_query, &q);
+        if (r < 0)
+                return r;
+
+        q->type = REQUEST_ADDRINFO;
+        q->getaddrinfo_handler = callback;
+        q->userdata = userdata;
+
+        node_len = node ? strlen(node) + 1 : 0;
+        service_len = service ? strlen(service) + 1 : 0;
+
+        req = (AddrInfoRequest) {
+                .node_len = node_len,
+                .service_len = service_len,
+
+                .header.id = q->id,
+                .header.type = REQUEST_ADDRINFO,
+                .header.length = sizeof(AddrInfoRequest) + node_len + service_len,
+
+                .hints_valid = hints,
+                .ai_flags = hints ? hints->ai_flags : 0,
+                .ai_family = hints ? hints->ai_family : 0,
+                .ai_socktype = hints ? hints->ai_socktype : 0,
+                .ai_protocol = hints ? hints->ai_protocol : 0,
+        };
+
+        msan_unpoison(&req, sizeof(req));
+
+        iov[mh.msg_iovlen++] = IOVEC_MAKE(&req, sizeof(AddrInfoRequest));
+        if (node)
+                iov[mh.msg_iovlen++] = IOVEC_MAKE((void*) node, req.node_len);
+        if (service)
+                iov[mh.msg_iovlen++] = IOVEC_MAKE((void*) service, req.service_len);
+        mh.msg_iov = iov;
+
+        if (sendmsg(resolve->fds[REQUEST_SEND_FD], &mh, MSG_NOSIGNAL) < 0)
+                return -errno;
+
+        resolve->n_outstanding++;
+        q->destroy_callback = destroy_callback;
+
+        if (ret_query)
+                *ret_query = q;
+
+        TAKE_PTR(q);
+
+        return 0;
+}
+
+_public_ int sd_resolve_getaddrinfo(
+                sd_resolve *resolve,
+                sd_resolve_query **ret_query,
+                const char *node, const char *service,
+                const struct addrinfo *hints,
+                sd_resolve_getaddrinfo_handler_t callback,
+                void *userdata) {
+
+        return resolve_getaddrinfo_with_destroy_callback(resolve, ret_query, node, service, hints, callback, NULL, userdata);
+}
+
+static int getaddrinfo_done(sd_resolve_query* q) {
+        assert(q);
+        assert(q->done);
+        assert(q->getaddrinfo_handler);
+
+        errno = q->_errno;
+        h_errno = q->_h_errno;
+
+        return q->getaddrinfo_handler(q, q->ret, q->addrinfo, q->userdata);
+}
+
+int resolve_getnameinfo_with_destroy_callback(
+                sd_resolve *resolve,
+                sd_resolve_query **ret_query,
+                const struct sockaddr *sa, socklen_t salen,
+                int flags,
+                uint64_t get,
+                sd_resolve_getnameinfo_handler_t callback,
+                sd_resolve_destroy_t destroy_callback,
+                void *userdata) {
+
+        _cleanup_(sd_resolve_query_unrefp) sd_resolve_query *q = NULL;
+        NameInfoRequest req = {};
+        struct iovec iov[2];
+        struct msghdr mh;
+        int r;
+
+        assert_return(resolve, -EINVAL);
+        assert_return(sa, -EINVAL);
+        assert_return(salen >= sizeof(struct sockaddr), -EINVAL);
+        assert_return(salen <= sizeof(union sockaddr_union), -EINVAL);
+        assert_return((get & ~SD_RESOLVE_GET_BOTH) == 0, -EINVAL);
+        assert_return(callback, -EINVAL);
+        assert_return(!resolve_pid_changed(resolve), -ECHILD);
+
+        r = alloc_query(resolve, !ret_query, &q);
+        if (r < 0)
+                return r;
+
+        q->type = REQUEST_NAMEINFO;
+        q->getnameinfo_handler = callback;
+        q->userdata = userdata;
+
+        req = (NameInfoRequest) {
+                .header.id = q->id,
+                .header.type = REQUEST_NAMEINFO,
+                .header.length = sizeof(NameInfoRequest) + salen,
+
+                .flags = flags,
+                .sockaddr_len = salen,
+                .gethost = !!(get & SD_RESOLVE_GET_HOST),
+                .getserv = !!(get & SD_RESOLVE_GET_SERVICE),
+        };
+
+        msan_unpoison(&req, sizeof(req));
+
+        iov[0] = IOVEC_MAKE(&req, sizeof(NameInfoRequest));
+        iov[1] = IOVEC_MAKE((void*) sa, salen);
+
+        mh = (struct msghdr) {
+                .msg_iov = iov,
+                .msg_iovlen = ELEMENTSOF(iov)
+        };
+
+        if (sendmsg(resolve->fds[REQUEST_SEND_FD], &mh, MSG_NOSIGNAL) < 0)
+                return -errno;
+
+        resolve->n_outstanding++;
+        q->destroy_callback = destroy_callback;
+
+        if (ret_query)
+                *ret_query = q;
+
+        TAKE_PTR(q);
+
+        return 0;
+}
+
+_public_ int sd_resolve_getnameinfo(
+                sd_resolve *resolve,
+                sd_resolve_query **ret_query,
+                const struct sockaddr *sa, socklen_t salen,
+                int flags,
+                uint64_t get,
+                sd_resolve_getnameinfo_handler_t callback,
+                void *userdata) {
+
+        return resolve_getnameinfo_with_destroy_callback(resolve, ret_query, sa, salen, flags, get, callback, NULL, userdata);
+}
+
+static int getnameinfo_done(sd_resolve_query *q) {
+
+        assert(q);
+        assert(q->done);
+        assert(q->getnameinfo_handler);
+
+        errno = q->_errno;
+        h_errno = q->_h_errno;
+
+        return q->getnameinfo_handler(q, q->ret, q->host, q->serv, q->userdata);
+}
+
+static void resolve_freeaddrinfo(struct addrinfo *ai) {
+        while (ai) {
+                struct addrinfo *next = ai->ai_next;
+
+                free(ai->ai_addr);
+                free(ai->ai_canonname);
+                free(ai);
+                ai = next;
+        }
+}
+
+static void resolve_query_disconnect(sd_resolve_query *q) {
+        sd_resolve *resolve;
+        unsigned i;
+
+        assert(q);
+
+        if (!q->resolve)
+                return;
+
+        resolve = q->resolve;
+        assert(resolve->n_queries > 0);
+
+        if (q->done) {
+                assert(resolve->n_done > 0);
+                resolve->n_done--;
+        }
+
+        i = q->id % QUERIES_MAX;
+        assert(resolve->query_array[i] == q);
+        resolve->query_array[i] = NULL;
+        LIST_REMOVE(queries, resolve->queries, q);
+        resolve->n_queries--;
+
+        q->resolve = NULL;
+        if (!q->floating)
+                sd_resolve_unref(resolve);
+}
+
+static sd_resolve_query *resolve_query_free(sd_resolve_query *q) {
+        assert(q);
+
+        resolve_query_disconnect(q);
+
+        if (q->destroy_callback)
+                q->destroy_callback(q->userdata);
+
+        resolve_freeaddrinfo(q->addrinfo);
+        free(q->host);
+        free(q->serv);
+
+        return mfree(q);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_resolve_query, sd_resolve_query, resolve_query_free);
+
+_public_ int sd_resolve_query_is_done(sd_resolve_query *q) {
+        assert_return(q, -EINVAL);
+        assert_return(!resolve_pid_changed(q->resolve), -ECHILD);
+
+        return q->done;
+}
+
+_public_ void* sd_resolve_query_set_userdata(sd_resolve_query *q, void *userdata) {
+        void *ret;
+
+        assert_return(q, NULL);
+        assert_return(!resolve_pid_changed(q->resolve), NULL);
+
+        ret = q->userdata;
+        q->userdata = userdata;
+
+        return ret;
+}
+
+_public_ void* sd_resolve_query_get_userdata(sd_resolve_query *q) {
+        assert_return(q, NULL);
+        assert_return(!resolve_pid_changed(q->resolve), NULL);
+
+        return q->userdata;
+}
+
+_public_ sd_resolve *sd_resolve_query_get_resolve(sd_resolve_query *q) {
+        assert_return(q, NULL);
+        assert_return(!resolve_pid_changed(q->resolve), NULL);
+
+        return q->resolve;
+}
+
+_public_ int sd_resolve_query_get_destroy_callback(sd_resolve_query *q, sd_resolve_destroy_t *destroy_callback) {
+        assert_return(q, -EINVAL);
+
+        if (destroy_callback)
+                *destroy_callback = q->destroy_callback;
+
+        return !!q->destroy_callback;
+}
+
+_public_ int sd_resolve_query_set_destroy_callback(sd_resolve_query *q, sd_resolve_destroy_t destroy_callback) {
+        assert_return(q, -EINVAL);
+
+        q->destroy_callback = destroy_callback;
+        return 0;
+}
+
+_public_ int sd_resolve_query_get_floating(sd_resolve_query *q) {
+        assert_return(q, -EINVAL);
+
+        return q->floating;
+}
+
+_public_ int sd_resolve_query_set_floating(sd_resolve_query *q, int b) {
+        assert_return(q, -EINVAL);
+
+        if (q->floating == !!b)
+                return 0;
+
+        if (!q->resolve) /* Already disconnected */
+                return -ESTALE;
+
+        q->floating = b;
+
+        if (b) {
+                sd_resolve_query_ref(q);
+                sd_resolve_unref(q->resolve);
+        } else {
+                sd_resolve_ref(q->resolve);
+                sd_resolve_query_unref(q);
+        }
+
+        return 1;
+}
+
+static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        sd_resolve *resolve = userdata;
+        int r;
+
+        assert(resolve);
+
+        r = sd_resolve_process(resolve);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+_public_ int sd_resolve_attach_event(sd_resolve *resolve, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(resolve, -EINVAL);
+        assert_return(!resolve->event, -EBUSY);
+
+        assert(!resolve->event_source);
+
+        if (event)
+                resolve->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&resolve->event);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_event_add_io(resolve->event, &resolve->event_source, resolve->fds[RESPONSE_RECV_FD], POLLIN, io_callback, resolve);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(resolve->event_source, priority);
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        sd_resolve_detach_event(resolve);
+        return r;
+}
+
+_public_  int sd_resolve_detach_event(sd_resolve *resolve) {
+        assert_return(resolve, -EINVAL);
+
+        if (!resolve->event)
+                return 0;
+
+        if (resolve->event_source) {
+                sd_event_source_set_enabled(resolve->event_source, SD_EVENT_OFF);
+                resolve->event_source = sd_event_source_unref(resolve->event_source);
+        }
+
+        resolve->event = sd_event_unref(resolve->event);
+        return 1;
+}
+
+_public_ sd_event *sd_resolve_get_event(sd_resolve *resolve) {
+        assert_return(resolve, NULL);
+
+        return resolve->event;
+}
diff --git a/src/libsystemd/sd-resolve/test-resolve.c b/src/libsystemd/sd-resolve/test-resolve.c
new file mode 100644
index 0000000..b973dfd
--- /dev/null
+++ b/src/libsystemd/sd-resolve/test-resolve.c
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <resolv.h>
+#include <stdio.h>
+
+#include "sd-resolve.h"
+
+#include "alloc-util.h"
+#include "macro.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "time-util.h"
+
+#define TEST_TIMEOUT_USEC (20*USEC_PER_SEC)
+
+static int getaddrinfo_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
+        const struct addrinfo *i;
+
+        assert_se(q);
+
+        if (ret != 0) {
+                log_error("getaddrinfo error: %s %i", gai_strerror(ret), ret);
+                return 0;
+        }
+
+        for (i = ai; i; i = i->ai_next) {
+                _cleanup_free_ char *addr = NULL;
+
+                assert_se(sockaddr_pretty(i->ai_addr, i->ai_addrlen, false, true, &addr) == 0);
+                puts(addr);
+        }
+
+        printf("canonical name: %s\n", strna(ai->ai_canonname));
+
+        return 0;
+}
+
+static int getnameinfo_handler(sd_resolve_query *q, int ret, const char *host, const char *serv, void *userdata) {
+        assert_se(q);
+
+        if (ret != 0) {
+                log_error("getnameinfo error: %s %i", gai_strerror(ret), ret);
+                return 0;
+        }
+
+        printf("Host: %s — Serv: %s\n", strna(host), strna(serv));
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_resolve_query_unrefp) sd_resolve_query *q1 = NULL, *q2 = NULL;
+        _cleanup_(sd_resolve_unrefp) sd_resolve *resolve = NULL;
+        int r;
+
+        struct addrinfo hints = {
+                .ai_family = AF_UNSPEC,
+                .ai_socktype = SOCK_STREAM,
+                .ai_flags = AI_CANONNAME
+        };
+
+        struct sockaddr_in sa = {
+                .sin_family = AF_INET,
+                .sin_port = htobe16(80)
+        };
+
+        assert_se(sd_resolve_default(&resolve) >= 0);
+
+        /* Test a floating resolver query */
+        r = sd_resolve_getaddrinfo(resolve, NULL, "redhat.com", "http", NULL, getaddrinfo_handler, NULL);
+        if (r < 0)
+                log_error_errno(r, "sd_resolve_getaddrinfo(): %m");
+
+        /* Make a name -> address query */
+        r = sd_resolve_getaddrinfo(resolve, &q1, argc >= 2 ? argv[1] : "www.heise.de", NULL, &hints, getaddrinfo_handler, NULL);
+        if (r < 0)
+                log_error_errno(r, "sd_resolve_getaddrinfo(): %m");
+
+        /* Make an address -> name query */
+        sa.sin_addr.s_addr = inet_addr(argc >= 3 ? argv[2] : "193.99.144.71");
+        r = sd_resolve_getnameinfo(resolve, &q2, (struct sockaddr*) &sa, sizeof(sa), 0, SD_RESOLVE_GET_BOTH, getnameinfo_handler, NULL);
+        if (r < 0)
+                log_error_errno(r, "sd_resolve_getnameinfo(): %m");
+
+        /* Wait until all queries are completed */
+        for (;;) {
+                r = sd_resolve_wait(resolve, TEST_TIMEOUT_USEC);
+                if (r == 0)
+                        break;
+                if (r == -ETIMEDOUT) {
+                        /* Let's catch timeouts here, so that we can run safely in a CI that has no reliable DNS. Note
+                         * that we invoke exit() directly here, as the stuck NSS call will not allow us to exit
+                         * cleanly. */
+
+                        log_notice_errno(r, "sd_resolve_wait() timed out, but that's OK");
+                        exit(EXIT_SUCCESS);
+                }
+                if (r < 0) {
+                        log_error_errno(r, "sd_resolve_wait(): %m");
+                        assert_not_reached("sd_resolve_wait() failed");
+                }
+        }
+
+        return 0;
+}
diff --git a/src/libsystemd/sd-utf8/sd-utf8.c b/src/libsystemd/sd-utf8/sd-utf8.c
new file mode 100644
index 0000000..82fa125
--- /dev/null
+++ b/src/libsystemd/sd-utf8/sd-utf8.c
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "sd-utf8.h"
+
+#include "utf8.h"
+#include "util.h"
+
+_public_ const char *sd_utf8_is_valid(const char *s) {
+        assert_return(s, NULL);
+
+        return utf8_is_valid(s);
+}
+
+_public_ const char *sd_ascii_is_valid(const char *s) {
+        assert_return(s, NULL);
+
+        return ascii_is_valid(s);
+}