Adding upstream version 255.4.upstream/255.4

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

1 files changed, 139 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..ad61614
--- /dev/null
+++ b/src/libsystemd-network/arp-util.c
@@ -0,0 +1,139 @@
+/* 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 "ether-addr-util.h"
+#include "fd-util.h"
+#include "in-addr-util.h"
+#include "unaligned.h"
+
+int arp_update_filter(int fd, const struct in_addr *a, const struct ether_addr *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_LDX + BPF_IMM, unaligned_read_be32(&mac->ether_addr_octet[0])),   /* X <- 4 bytes of client's MAC */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_sha)),       /* A <- 4 bytes of SHA */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_X, 0, 0, 4),                                  /* A == X ? */
+                BPF_STMT(BPF_LDX + BPF_IMM, unaligned_read_be16(&mac->ether_addr_octet[4])),   /* X <- remainder of client's MAC */
+                BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, arp_sha) + 4),   /* A <- remainder of SHA */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_X, 0, 0, 1),                                  /* A == X ? */
+                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_LDX + BPF_IMM, htobe32(a->s_addr)),                               /* X <- clients IP */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_spa)),       /* A <- SPA */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_X, 0, 0, 1),                                  /* A == X ? */
+                BPF_STMT(BPF_RET + BPF_K, UINT32_MAX),                                         /* accept */
+                BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_tpa)),       /* A <- TPA */
+                BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_X, 0, 0, 1),                                  /* A == 0 ? */
+                BPF_STMT(BPF_RET + BPF_K, UINT32_MAX),                                         /* accept */
+                BPF_STMT(BPF_RET + BPF_K, 0),                                                  /* ignore */
+        };
+        struct sock_fprog fprog = {
+                .len    = ELEMENTSOF(filter),
+                .filter = (struct sock_filter*) filter,
+        };
+
+        assert(fd >= 0);
+
+        if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int arp_network_bind_raw_socket(int ifindex, const struct in_addr *a, const struct ether_addr *mac) {
+        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 = -EBADF;
+        int r;
+
+        assert(ifindex > 0);
+        assert(mac);
+
+        s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+        if (s < 0)
+                return -errno;
+
+        r = arp_update_filter(s, a, mac);
+        if (r < 0)
+                return r;
+
+        if (bind(s, &link.sa, sizeof(link.ll)) < 0)
+                return -errno;
+
+        return TAKE_FD(s);
+}
+
+int arp_send_packet(
+                int fd,
+                int ifindex,
+                const struct in_addr *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(struct in_addr), /* PLEN */
+                .ea_hdr.ar_op  = htobe16(ARPOP_REQUEST), /* REQUEST */
+        };
+        ssize_t n;
+
+        assert(fd >= 0);
+        assert(ifindex > 0);
+        assert(pa);
+        assert(in4_addr_is_set(pa));
+        assert(ha);
+        assert(!ether_addr_is_null(ha));
+
+        memcpy(&arp.arp_sha, ha, ETH_ALEN);
+        memcpy(&arp.arp_tpa, pa, sizeof(struct in_addr));
+
+        if (announce)
+                memcpy(&arp.arp_spa, pa, sizeof(struct in_addr));
+
+        n = sendto(fd, &arp, sizeof(struct ether_arp), 0, &link.sa, sizeof(link.ll));
+        if (n < 0)
+                return -errno;
+        if (n != sizeof(struct ether_arp))
+                return -EIO;
+
+        return 0;
+}