Adding upstream version 255.4.upstream/255.4

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

1 files changed, 1161 insertions, 0 deletions

diff --git a/src/libsystemd-network/sd-radv.c b/src/libsystemd-network/sd-radv.c
new file mode 100644
index 0000000..97d306c
--- /dev/null
+++ b/src/libsystemd-network/sd-radv.c
@@ -0,0 +1,1161 @@
+/* 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 "iovec-util.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "network-common.h"
+#include "radv-internal.h"
+#include "random-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "unaligned.h"
+
+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 = -EBADF,
+                .lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
+        };
+
+        *ret = TAKE_PTR(ra);
+
+        return 0;
+}
+
+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;
+}
+
+int sd_radv_detach_event(sd_radv *ra) {
+
+        assert_return(ra, -EINVAL);
+
+        ra->event = sd_event_unref(ra->event);
+        return 0;
+}
+
+sd_event *sd_radv_get_event(sd_radv *ra) {
+        assert_return(ra, NULL);
+
+        return ra->event;
+}
+
+int sd_radv_is_running(sd_radv *ra) {
+        assert_return(ra, false);
+
+        return ra->state != 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_disable_unref(ra->recv_event_source);
+
+        ra->ra_sent = 0;
+}
+
+static sd_radv *radv_free(sd_radv *ra) {
+        if (!ra)
+                return NULL;
+
+        LIST_CLEAR(prefix, ra->prefixes, sd_radv_prefix_unref);
+        LIST_CLEAR(prefix, ra->route_prefixes, sd_radv_route_prefix_unref);
+        LIST_CLEAR(prefix, ra->pref64_prefixes, sd_radv_pref64_prefix_unref);
+
+        free(ra->rdnss);
+        free(ra->dnssl);
+
+        radv_reset(ra);
+
+        sd_event_source_unref(ra->timeout_event_source);
+        sd_radv_detach_event(ra);
+
+        ra->fd = safe_close(ra->fd);
+        free(ra->ifname);
+
+        return mfree(ra);
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
+
+static bool router_lifetime_is_valid(usec_t lifetime_usec) {
+        return lifetime_usec == 0 ||
+                (lifetime_usec >= RADV_MIN_ROUTER_LIFETIME_USEC &&
+                 lifetime_usec <= RADV_MAX_ROUTER_LIFETIME_USEC);
+}
+
+static int radv_send(sd_radv *ra, const struct in6_addr *dst, usec_t lifetime_usec) {
+        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, N pref64 prefixes, RDNSS,
+         * DNSSL, and home agent. */
+        struct iovec iov[6 + ra->n_prefixes + ra->n_route_prefixes + ra->n_pref64_prefixes];
+        struct msghdr msg = {
+                .msg_name = &dst_addr,
+                .msg_namelen = sizeof(dst_addr),
+                .msg_iov = iov,
+        };
+        usec_t time_now;
+        int r;
+
+        assert(ra);
+        assert(router_lifetime_is_valid(lifetime_usec));
+
+        r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
+        if (r < 0)
+                return r;
+
+        if (dst && in6_addr_is_set(dst))
+                dst_addr.sin6_addr = *dst;
+
+        adv.nd_ra_type = ND_ROUTER_ADVERT;
+        adv.nd_ra_curhoplimit = ra->hop_limit;
+        adv.nd_ra_retransmit = usec_to_be32_msec(ra->retransmit_usec);
+        adv.nd_ra_flags_reserved = ra->flags;
+        assert_cc(RADV_MAX_ROUTER_LIFETIME_USEC <= UINT16_MAX * USEC_PER_SEC);
+        adv.nd_ra_router_lifetime = usec_to_be16_sec(lifetime_usec);
+        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 > 0) {
+                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) {
+                usec_t lifetime_valid_usec, lifetime_preferred_usec;
+
+                lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
+                                          p->lifetime_valid_usec);
+
+                lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
+                                               p->lifetime_preferred_usec,
+                                               lifetime_valid_usec);
+
+                p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
+                p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
+
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
+        }
+
+        LIST_FOREACH(prefix, rt, ra->route_prefixes) {
+                rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
+                                                        rt->lifetime_usec));
+
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
+        }
+
+        LIST_FOREACH(prefix, p, ra->pref64_prefixes)
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->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 (FLAGS_SET(ra->flags, ND_RA_FLAG_HOME_AGENT)) {
+                ra->home_agent.nd_opt_home_agent_info_type = ND_OPT_HOME_AGENT_INFO;
+                ra->home_agent.nd_opt_home_agent_info_len = 1;
+
+                /* 0 means to place the current Router Lifetime value */
+                if (ra->home_agent.nd_opt_home_agent_info_lifetime == 0)
+                        ra->home_agent.nd_opt_home_agent_info_lifetime = adv.nd_ra_router_lifetime;
+
+                iov[msg.msg_iovlen++] = IOVEC_MAKE(&ra->home_agent, sizeof(ra->home_agent));
+        }
+
+        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 = ASSERT_PTR(userdata);
+        struct in6_addr src;
+        triple_timestamp timestamp;
+        int r;
+
+        assert(s);
+        assert(ra->event);
+
+        ssize_t buflen = next_datagram_size_fd(fd);
+        if (ERRNO_IS_NEG_TRANSIENT(buflen) || ERRNO_IS_NEG_DISCONNECT(buflen))
+                return 0;
+        if (buflen < 0) {
+                log_radv_errno(ra, buflen, "Failed to determine datagram size to read, ignoring: %m");
+                return 0;
+        }
+
+        _cleanup_free_ char *buf = new0(char, buflen);
+        if (!buf)
+                return -ENOMEM;
+
+        r = icmp6_receive(fd, buf, buflen, &src, &timestamp);
+        if (ERRNO_IS_NEG_TRANSIENT(r) || ERRNO_IS_NEG_DISCONNECT(r))
+                return 0;
+        if (r < 0)
+                switch (r) {
+                case -EADDRNOTAVAIL:
+                        log_radv(ra, "Received RS from neither link-local nor null address. Ignoring");
+                        return 0;
+
+                case -EMULTIHOP:
+                        log_radv(ra, "Received RS with invalid hop limit. Ignoring.");
+                        return 0;
+
+                case -EPFNOSUPPORT:
+                        log_radv(ra, "Received invalid source address from ICMPv6 socket. Ignoring.");
+                        return 0;
+
+                default:
+                        log_radv_errno(ra, r, "Unexpected error receiving from ICMPv6 socket, ignoring: %m");
+                        return 0;
+                }
+
+        if ((size_t) buflen < sizeof(struct nd_router_solicit)) {
+                log_radv(ra, "Too short packet received, ignoring");
+                return 0;
+        }
+
+        /* TODO: if the sender address is null, check that the message does not have the source link-layer
+         * address option. See RFC 4861 Section 6.1.1. */
+
+        const char *addr = IN6_ADDR_TO_STRING(&src);
+
+        r = radv_send(ra, &src, ra->lifetime_usec);
+        if (r < 0)
+                log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", addr);
+        else
+                log_radv(ra, "Sent solicited Router Advertisement to %s", addr);
+
+        return 0;
+}
+
+static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
+        usec_t min_timeout, max_timeout, time_now, timeout;
+        sd_radv *ra = ASSERT_PTR(userdata);
+        int r;
+
+        assert(s);
+        assert(ra->event);
+        assert(router_lifetime_is_valid(ra->lifetime_usec));
+
+        r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
+        if (r < 0)
+                goto fail;
+
+        r = radv_send(ra, NULL, ra->lifetime_usec);
+        if (r < 0)
+                log_radv_errno(ra, r, "Unable to send Router Advertisement, ignoring: %m");
+
+        /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
+        if (ra->ra_sent < RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
+                max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
+        else
+                max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
+
+        /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
+         * so lower the interval here */
+        if (ra->lifetime_usec > 0)
+                max_timeout = MIN(max_timeout, ra->lifetime_usec);
+
+        if (max_timeout >= 9 * USEC_PER_SEC)
+                min_timeout = max_timeout / 3;
+        else
+                min_timeout = max_timeout * 3 / 4;
+
+        /* RFC 4861, Section 6.2.1.
+         * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
+         * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
+        assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
+        assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
+        assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
+        assert(min_timeout <= max_timeout * 3 / 4);
+
+        timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
+        log_radv(ra, "Next Router Advertisement in %s", FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
+
+        r = event_reset_time(ra->event, &ra->timeout_event_source,
+                             CLOCK_BOOTTIME,
+                             usec_add(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;
+}
+
+int sd_radv_stop(sd_radv *ra) {
+        int r;
+
+        if (!ra)
+                return 0;
+
+        if (ra->state == RADV_STATE_IDLE)
+                return 0;
+
+        log_radv(ra, "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(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
+
+        radv_reset(ra);
+        ra->fd = safe_close(ra->fd);
+        ra->state = RADV_STATE_IDLE;
+
+        return 0;
+}
+
+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 != RADV_STATE_IDLE)
+                return 0;
+
+        r = event_reset_time(ra->event, &ra->timeout_event_source,
+                             CLOCK_BOOTTIME,
+                             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 = RADV_STATE_ADVERTISING;
+
+        log_radv(ra, "Started IPv6 Router Advertisement daemon");
+
+        return 0;
+
+ fail:
+        radv_reset(ra);
+
+        return r;
+}
+
+int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
+        assert_return(ra, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        ra->ifindex = ifindex;
+
+        return 0;
+}
+
+int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
+        assert_return(ra, -EINVAL);
+        assert_return(ifname, -EINVAL);
+
+        if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
+                return -EINVAL;
+
+        return free_and_strdup(&ra->ifname, ifname);
+}
+
+int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
+        int r;
+
+        assert_return(ra, -EINVAL);
+
+        r = get_ifname(ra->ifindex, &ra->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = ra->ifname;
+
+        return 0;
+}
+
+int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        if (mac_addr)
+                ra->mac_addr = *mac_addr;
+        else
+                zero(ra->mac_addr);
+
+        return 0;
+}
+
+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;
+}
+
+int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        ra->hop_limit = hop_limit;
+
+        return 0;
+}
+
+int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        if (usec > RADV_MAX_RETRANSMIT_USEC)
+                return -EINVAL;
+
+        ra->retransmit_usec = usec;
+        return 0;
+}
+
+int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        if (!router_lifetime_is_valid(usec))
+                return -EINVAL;
+
+        /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
+         * to (00) by the sender..." */
+        if (usec == 0 &&
+            (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
+                return -EINVAL;
+
+        ra->lifetime_usec = usec;
+        return 0;
+}
+
+int sd_radv_set_managed_information(sd_radv *ra, int managed) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
+
+        return 0;
+}
+
+int sd_radv_set_other_information(sd_radv *ra, int other) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
+
+        return 0;
+}
+
+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_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
+                return -EINVAL;
+
+        ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
+
+        return 0;
+}
+
+int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
+
+        return 0;
+}
+
+int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
+
+        return 0;
+}
+
+int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
+        assert_return(ra, -EINVAL);
+
+        if (ra->state != RADV_STATE_IDLE)
+                return -EBUSY;
+
+        if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
+                return -EINVAL;
+
+        ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
+        return 0;
+}
+
+int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
+        sd_radv_prefix *found = NULL;
+        int r;
+
+        assert_return(ra, -EINVAL);
+        assert_return(p, -EINVAL);
+
+        /* Refuse prefixes that don't have a prefix set */
+        if (in6_addr_is_null(&p->opt.in6_addr))
+                return -ENOEXEC;
+
+        const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
+
+        LIST_FOREACH(prefix, cur, ra->prefixes) {
+                r = in_addr_prefix_intersect(AF_INET6,
+                                             (const union in_addr_union*) &cur->opt.in6_addr,
+                                             cur->opt.prefixlen,
+                                             (const union in_addr_union*) &p->opt.in6_addr,
+                                             p->opt.prefixlen);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (cur->opt.prefixlen == p->opt.prefixlen) {
+                        found = cur;
+                        break;
+                }
+
+                return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
+                                      "IPv6 prefix %s conflicts with %s, ignoring.",
+                                      addr_p,
+                                      IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
+        }
+
+        if (found) {
+                /* p and cur may be equivalent. First increment the reference counter. */
+                sd_radv_prefix_ref(p);
+
+                /* Then, remove the old entry. */
+                LIST_REMOVE(prefix, ra->prefixes, found);
+                sd_radv_prefix_unref(found);
+
+                /* Finally, add the new entry. */
+                LIST_APPEND(prefix, ra->prefixes, p);
+
+                log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
+                         addr_p,
+                         FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
+                         FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
+        } else {
+                /* The prefix is new. Let's simply add it. */
+
+                sd_radv_prefix_ref(p);
+                LIST_APPEND(prefix, ra->prefixes, p);
+                ra->n_prefixes++;
+
+                log_radv(ra, "Added prefix %s", addr_p);
+        }
+
+        if (ra->state == RADV_STATE_IDLE)
+                return 0;
+
+        if (ra->ra_sent == 0)
+                return 0;
+
+        /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
+        r = radv_send(ra, NULL, ra->lifetime_usec);
+        if (r < 0)
+                log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
+        else
+                log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
+
+        return 0;
+}
+
+void sd_radv_remove_prefix(
+                sd_radv *ra,
+                const struct in6_addr *prefix,
+                unsigned char prefixlen) {
+
+        if (!ra)
+                return;
+
+        if (!prefix)
+                return;
+
+        LIST_FOREACH(prefix, cur, ra->prefixes) {
+                if (prefixlen != cur->opt.prefixlen)
+                        continue;
+
+                if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
+                        continue;
+
+                LIST_REMOVE(prefix, ra->prefixes, cur);
+                ra->n_prefixes--;
+                sd_radv_prefix_unref(cur);
+                return;
+        }
+}
+
+int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
+        sd_radv_route_prefix *found = NULL;
+        int r;
+
+        assert_return(ra, -EINVAL);
+        assert_return(p, -EINVAL);
+
+        const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
+
+        LIST_FOREACH(prefix, cur, ra->route_prefixes) {
+                r = in_addr_prefix_intersect(AF_INET6,
+                                             (const union in_addr_union*) &cur->opt.in6_addr,
+                                             cur->opt.prefixlen,
+                                             (const union in_addr_union*) &p->opt.in6_addr,
+                                             p->opt.prefixlen);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (cur->opt.prefixlen == p->opt.prefixlen) {
+                        found = cur;
+                        break;
+                }
+
+                return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
+                                      "IPv6 route prefix %s conflicts with %s, ignoring.",
+                                      addr_p,
+                                      IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
+        }
+
+        if (found) {
+                /* p and cur may be equivalent. First increment the reference counter. */
+                sd_radv_route_prefix_ref(p);
+
+                /* Then, remove the old entry. */
+                LIST_REMOVE(prefix, ra->route_prefixes, found);
+                sd_radv_route_prefix_unref(found);
+
+                /* Finally, add the new entry. */
+                LIST_APPEND(prefix, ra->route_prefixes, p);
+
+                log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
+                         strna(addr_p),
+                         FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
+        } else {
+                /* The route prefix is new. Let's simply add it. */
+
+                sd_radv_route_prefix_ref(p);
+                LIST_APPEND(prefix, ra->route_prefixes, p);
+                ra->n_route_prefixes++;
+
+                log_radv(ra, "Added route prefix %s", strna(addr_p));
+        }
+
+        if (ra->state == RADV_STATE_IDLE)
+                return 0;
+
+        if (ra->ra_sent == 0)
+                return 0;
+
+        /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
+        r = radv_send(ra, NULL, ra->lifetime_usec);
+        if (r < 0)
+                log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
+                               strna(addr_p));
+        else
+                log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
+
+        return 0;
+}
+
+int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
+        sd_radv_pref64_prefix *found = NULL;
+        int r;
+
+        assert_return(ra, -EINVAL);
+        assert_return(p, -EINVAL);
+
+        const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
+
+        LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
+                r = in_addr_prefix_intersect(AF_INET6,
+                                             (const union in_addr_union*) &cur->in6_addr,
+                                             cur->prefixlen,
+                                             (const union in_addr_union*) &p->in6_addr,
+                                             p->prefixlen);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                if (cur->prefixlen == p->prefixlen) {
+                        found = cur;
+                        break;
+                }
+
+                return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
+                                      "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
+                                      addr_p,
+                                      IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
+        }
+
+        if (found) {
+                /* p and cur may be equivalent. First increment the reference counter. */
+                sd_radv_pref64_prefix_ref(p);
+
+                /* Then, remove the old entry. */
+                LIST_REMOVE(prefix, ra->pref64_prefixes, found);
+                sd_radv_pref64_prefix_unref(found);
+
+                /* Finally, add the new entry. */
+                LIST_APPEND(prefix, ra->pref64_prefixes, p);
+
+                log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
+                         strna(addr_p),
+                         FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
+        } else {
+                /* The route prefix is new. Let's simply add it. */
+
+                sd_radv_pref64_prefix_ref(p);
+                LIST_APPEND(prefix, ra->pref64_prefixes, p);
+                ra->n_pref64_prefixes++;
+
+                log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
+        }
+
+        if (ra->state == RADV_STATE_IDLE)
+                return 0;
+
+        if (ra->ra_sent == 0)
+                return 0;
+
+        /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
+        r = radv_send(ra, NULL, ra->lifetime_usec);
+        if (r < 0)
+                log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
+                               strna(addr_p));
+        else
+                log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
+
+        return 0;
+}
+
+int sd_radv_set_rdnss(
+                sd_radv *ra,
+                uint64_t lifetime_usec,
+                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 (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
+                return -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 = RADV_OPT_RDNSS;
+        opt_rdnss->length = len / 8;
+        opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
+
+        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;
+}
+
+int sd_radv_set_dnssl(
+                sd_radv *ra,
+                uint64_t lifetime_usec,
+                char **search_list) {
+
+        _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
+        size_t len = 0;
+        uint8_t *p;
+
+        assert_return(ra, -EINVAL);
+
+        if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
+                return -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 = RADV_OPT_DNSSL;
+        opt_dnssl->length = len / 8;
+        opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
+
+        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;
+}
+
+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,
+
+                .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
+                .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
+                .valid_until = USEC_INFINITY,
+                .preferred_until = USEC_INFINITY,
+        };
+
+        *ret = p;
+        return 0;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
+
+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(NULL, "Unusual prefix length %d greater than 64", prefixlen);
+
+        p->opt.in6_addr = *in6_addr;
+        p->opt.prefixlen = prefixlen;
+
+        return 0;
+}
+
+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;
+}
+
+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;
+}
+
+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;
+}
+
+int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
+        assert_return(p, -EINVAL);
+
+        p->lifetime_valid_usec = lifetime_usec;
+        p->valid_until = valid_until;
+
+        return 0;
+}
+
+int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
+        assert_return(p, -EINVAL);
+
+        p->lifetime_preferred_usec = lifetime_usec;
+        p->preferred_until = valid_until;
+
+        return 0;
+}
+
+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 = RADV_OPT_ROUTE_INFORMATION,
+                .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
+                .opt.prefixlen = 64,
+
+                .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
+                .valid_until = USEC_INFINITY,
+        };
+
+        *ret = p;
+        return 0;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
+
+int sd_radv_route_prefix_set_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(NULL, "Unusual prefix length %u greater than 64", prefixlen);
+
+        p->opt.in6_addr = *in6_addr;
+        p->opt.prefixlen = prefixlen;
+
+        return 0;
+}
+
+int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
+        assert_return(p, -EINVAL);
+
+        p->lifetime_usec = lifetime_usec;
+        p->valid_until = valid_until;
+
+        return 0;
+}
+
+int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
+        sd_radv_pref64_prefix *p;
+
+        assert_return(ret, -EINVAL);
+
+        p = new(sd_radv_pref64_prefix, 1);
+        if (!p)
+                return -ENOMEM;
+
+        *p = (sd_radv_pref64_prefix) {
+                .n_ref = 1,
+
+                .opt.type = RADV_OPT_PREF64,
+                .opt.length = 2,
+        };
+
+        *ret = p;
+        return 0;
+}
+
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
+
+int sd_radv_pref64_prefix_set_prefix(
+                sd_radv_pref64_prefix *p,
+                const struct in6_addr *prefix,
+                uint8_t prefixlen,
+                uint64_t lifetime_usec) {
+
+        uint16_t pref64_lifetime;
+        uint8_t prefixlen_code;
+        int r;
+
+        assert_return(p, -EINVAL);
+        assert_return(prefix, -EINVAL);
+
+        r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
+        if (r < 0)
+                return log_radv_errno(NULL, r,
+                                      "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
+
+        if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
+                return -EINVAL;
+
+        /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
+        pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
+        pref64_lifetime |= prefixlen_code;
+
+        unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
+        memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
+
+        p->in6_addr = *prefix;
+        p->prefixlen = prefixlen;
+
+        return 0;
+}