[thirdparty/systemd.git] / src / libsystemd-network / sd-radv.c

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  Copyright © 2017 Intel Corporation. All rights reserved.
***/

#include <netinet/icmp6.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "sd-radv.h"

#include "macro.h"
#include "alloc-util.h"
#include "dns-domain.h"
#include "fd-util.h"
#include "icmp6-util.h"
#include "in-addr-util.h"
#include "radv-internal.h"
#include "socket-util.h"
#include "string-util.h"
#include "strv.h"
#include "util.h"
#include "random-util.h"

_public_ int sd_radv_new(sd_radv **ret) {
        _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;

        assert_return(ret, -EINVAL);

        ra = new0(sd_radv, 1);
        if (!ra)
                return -ENOMEM;

        ra->n_ref = 1;
        ra->fd = -1;

        LIST_HEAD_INIT(ra->prefixes);

        *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;
}

static void radv_reset(sd_radv *ra) {
        assert(ra);

        ra->timeout_event_source =
                sd_event_source_unref(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) {
        assert(ra);

        while (ra->prefixes) {
                sd_radv_prefix *p = ra->prefixes;

                LIST_REMOVE(prefix, ra->prefixes, p);
                sd_radv_prefix_unref(p);
        }

        free(ra->rdnss);
        free(ra->dnssl);

        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,
                     const uint32_t router_lifetime) {
        static const struct ether_addr mac_zero = {};
        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, RDNSS
           and DNSSL */
        struct iovec iov[5 + ra->n_prefixes];
        struct msghdr msg = {
                .msg_name = &dst_addr,
                .msg_namelen = sizeof(dst_addr),
                .msg_iov = iov,
        };
        usec_t time_now;
        int r;

        r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
        if (r < 0)
                return r;

        if (dst && !in_addr_is_null(AF_INET6, (union in_addr_union*) 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].iov_base = &adv;
        iov[msg.msg_iovlen].iov_len = sizeof(adv);
        msg.msg_iovlen++;

        /* 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 (memcmp(&mac_zero, &ra->mac_addr, sizeof(mac_zero))) {
                opt_mac.slladdr = ra->mac_addr;
                iov[msg.msg_iovlen].iov_base = &opt_mac;
                iov[msg.msg_iovlen].iov_len = sizeof(opt_mac);
                msg.msg_iovlen++;
        }

        if (ra->mtu) {
                opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu);
                iov[msg.msg_iovlen].iov_base = &opt_mtu;
                iov[msg.msg_iovlen].iov_len = sizeof(opt_mtu);
                msg.msg_iovlen++;
        }

        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].iov_base = &p->opt;
                iov[msg.msg_iovlen].iov_len = sizeof(p->opt);
                msg.msg_iovlen++;
        }

        if (ra->rdnss) {
                iov[msg.msg_iovlen].iov_base = ra->rdnss;
                iov[msg.msg_iovlen].iov_len = ra->rdnss->length * 8;
                msg.msg_iovlen++;
        }

        if (ra->dnssl) {
                iov[msg.msg_iovlen].iov_base = ra->dnssl;
                iov[msg.msg_iovlen].iov_len = ra->dnssl->length * 8;
                msg.msg_iovlen++;
        }

        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 ((unsigned) buflen < sizeof(struct nd_router_solicit))
                return log_radv("Too short packet received");

        buf = new0(char, buflen);
        if (!buf)
                return 0;

        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;
        }

        (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", addr);
        else
                log_radv("Sent solicited Router Advertisement to %s", 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);

        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);

        ra->timeout_event_source = sd_event_source_unref(ra->timeout_event_source);

        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;
        }

        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 = sd_event_add_time(ra->event, &ra->timeout_event_source,
                              clock_boottime_or_monotonic(),
                              time_now + timeout, MSEC_PER_SEC,
                              radv_timeout, ra);
        if (r < 0)
                goto fail;

        r = sd_event_source_set_priority(ra->timeout_event_source,
                                         ra->event_priority);
        if (r < 0)
                goto fail;

        r = sd_event_source_set_description(ra->timeout_event_source,
                                            "radv-timeout");
        if (r < 0)
                goto fail;

        ra->ra_sent++;

fail:
        if (r < 0)
                sd_radv_stop(ra);

        return 0;
}

_public_ int sd_radv_stop(sd_radv *ra) {
        int r;

        assert_return(ra, -EINVAL);

        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 = 0;

        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 = sd_event_add_time(ra->event, &ra->timeout_event_source,
                              clock_boottime_or_monotonic(), 0, 0,
                              radv_timeout, ra);
        if (r < 0)
                goto fail;

        r = sd_event_source_set_priority(ra->timeout_event_source,
                                         ra->event_priority);
        if (r < 0)
                goto fail;

        (void) sd_event_source_set_description(ra->timeout_event_source,
                                               "radv-timeout");

        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 >= -1, -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, uint32_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) {
        int r = 0;

        assert_return(ra, -EINVAL);
        assert_return(IN_SET(preference,
                             SD_NDISC_PREFERENCE_LOW,
                             SD_NDISC_PREFERENCE_MEDIUM,
                             SD_NDISC_PREFERENCE_HIGH), -EINVAL);

        ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);

        return r;
}

_public_ int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p, bool 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;

        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;

 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("%s prefix %s/%u preferred %s valid %s",
                 cur? "Updated": "Added",
                 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--;

                break;
        }

        return cur;
}

_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) {
        _cleanup_(sd_radv_prefix_unrefp) sd_radv_prefix *p = NULL;

        assert_return(ret, -EINVAL);

        p = new0(sd_radv_prefix, 1);
        if (!p)
                return -ENOMEM;

        p->n_ref = 1;

        p->opt.type = ND_OPT_PREFIX_INFORMATION;
        p->opt.length = (sizeof(p->opt) - 1) /8 + 1;

        p->opt.prefixlen = 64;

        /* RFC 4861, Section 6.2.1 */
        SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, true);
        SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, true);
        p->opt.preferred_lifetime = htobe32(604800);
        p->opt.valid_lifetime = htobe32(2592000);

        LIST_INIT(prefix, p);

        *ret = TAKE_PTR(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_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;
}
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
04473969	2	/***
810adae9	3	Copyright © 2017 Intel Corporation. All rights reserved.
04473969 PF	4	***/
	5
	6	#include <netinet/icmp6.h>
	7	#include <netinet/in.h>
204f99d2	8	#include <arpa/inet.h>
04473969 PF	9
	10	#include "sd-radv.h"
	11
204f99d2	12	#include "macro.h"
04473969	13	#include "alloc-util.h"
e965d6ab	14	#include "dns-domain.h"
04473969 PF	15	#include "fd-util.h"
	16	#include "icmp6-util.h"
	17	#include "in-addr-util.h"
	18	#include "radv-internal.h"
	19	#include "socket-util.h"
	20	#include "string-util.h"
e965d6ab	21	#include "strv.h"
04473969	22	#include "util.h"
204fb681	23	#include "random-util.h"
04473969	24
204f99d2 PF	25	_public_ int sd_radv_new(sd_radv **ret) {
	26	_cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
	27
	28	assert_return(ret, -EINVAL);
	29
	30	ra = new0(sd_radv, 1);
	31	if (!ra)
	32	return -ENOMEM;
	33
	34	ra->n_ref = 1;
77baf5ae	35	ra->fd = -1;
204f99d2 PF	36
	37	LIST_HEAD_INIT(ra->prefixes);
	38
1cc6c93a	39	*ret = TAKE_PTR(ra);
204f99d2 PF	40
	41	return 0;
	42	}
	43
	44	_public_ int sd_radv_attach_event(sd_radv ra, sd_event event, int64_t priority) {
	45	int r;
	46
	47	assert_return(ra, -EINVAL);
	48	assert_return(!ra->event, -EBUSY);
	49
	50	if (event)
	51	ra->event = sd_event_ref(event);
	52	else {
	53	r = sd_event_default(&ra->event);
	54	if (r < 0)
	55	return 0;
	56	}
	57
	58	ra->event_priority = priority;
	59
	60	return 0;
	61	}
	62
	63	_public_ int sd_radv_detach_event(sd_radv *ra) {
	64
	65	assert_return(ra, -EINVAL);
	66
	67	ra->event = sd_event_unref(ra->event);
	68	return 0;
	69	}
	70
	71	_public_ sd_event sd_radv_get_event(sd_radv ra) {
	72	assert_return(ra, NULL);
	73
	74	return ra->event;
	75	}
	76
204fb681	77	static void radv_reset(sd_radv *ra) {
c4b6dda0	78	assert(ra);
204fb681 PF	79
	80	ra->timeout_event_source =
	81	sd_event_source_unref(ra->timeout_event_source);
	82
88d5a3db PF	83	ra->recv_event_source =
	84	sd_event_source_unref(ra->recv_event_source);
	85
204fb681 PF	86	ra->ra_sent = 0;
	87	}
	88
8301aa0b YW	89	static sd_radv radv_free(sd_radv ra) {
8301aa0b YW	90	assert(ra);
204f99d2 PF	91
	92	while (ra->prefixes) {
	93	sd_radv_prefix *p = ra->prefixes;
	94
	95	LIST_REMOVE(prefix, ra->prefixes, p);
	96	sd_radv_prefix_unref(p);
	97	}
	98
e9c6da38	99	free(ra->rdnss);
f9aa5417	100	free(ra->dnssl);
e9c6da38	101
204fb681 PF	102	radv_reset(ra);
204fb681 PF	103
204f99d2	104	sd_radv_detach_event(ra);
c4b6dda0 LP	105
	106	ra->fd = safe_close(ra->fd);
	107
204f99d2 PF	108	return mfree(ra);
	109	}
	110
8301aa0b YW	111	DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
8301aa0b YW	112
204fb681 PF	113	static int radv_send(sd_radv ra, const struct in6_addr dst,
204fb681 PF	114	const uint32_t router_lifetime) {
77baf5ae PF	115	static const struct ether_addr mac_zero = {};
	116	sd_radv_prefix *p;
	117	struct sockaddr_in6 dst_addr = {
	118	.sin6_family = AF_INET6,
	119	.sin6_addr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
	120	};
	121	struct nd_router_advert adv = {};
	122	struct {
	123	struct nd_opt_hdr opthdr;
	124	struct ether_addr slladdr;
	125	} _packed_ opt_mac = {
	126	.opthdr = {
	127	.nd_opt_type = ND_OPT_SOURCE_LINKADDR,
	128	.nd_opt_len = (sizeof(struct nd_opt_hdr) +
	129	sizeof(struct ether_addr) - 1) /8 + 1,
	130	},
	131	};
	132	struct nd_opt_mtu opt_mtu = {
	133	.nd_opt_mtu_type = ND_OPT_MTU,
	134	.nd_opt_mtu_len = 1,
	135	};
6852c0f6 PF	136	/* Reserve iov space for RA header, linkaddr, MTU, N prefixes, RDNSS
	137	and DNSSL */
	138	struct iovec iov[5 + ra->n_prefixes];
77baf5ae PF	139	struct msghdr msg = {
	140	.msg_name = &dst_addr,
	141	.msg_namelen = sizeof(dst_addr),
	142	.msg_iov = iov,
	143	};
d601b566 PF	144	usec_t time_now;
	145	int r;
	146
	147	r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
	148	if (r < 0)
	149	return r;
77baf5ae	150
88d5a3db	151	if (dst && !in_addr_is_null(AF_INET6, (union in_addr_union*) dst))
77baf5ae	152	dst_addr.sin6_addr = *dst;
88d5a3db	153
77baf5ae PF	154	adv.nd_ra_type = ND_ROUTER_ADVERT;
	155	adv.nd_ra_curhoplimit = ra->hop_limit;
	156	adv.nd_ra_flags_reserved = ra->flags;
	157	adv.nd_ra_router_lifetime = htobe16(router_lifetime);
	158	iov[msg.msg_iovlen].iov_base = &adv;
	159	iov[msg.msg_iovlen].iov_len = sizeof(adv);
	160	msg.msg_iovlen++;
	161
	162	/* MAC address is optional, either because the link does not use L2
	163	addresses or load sharing is desired. See RFC 4861, Section 4.2 */
	164	if (memcmp(&mac_zero, &ra->mac_addr, sizeof(mac_zero))) {
	165	opt_mac.slladdr = ra->mac_addr;
	166	iov[msg.msg_iovlen].iov_base = &opt_mac;
	167	iov[msg.msg_iovlen].iov_len = sizeof(opt_mac);
	168	msg.msg_iovlen++;
	169	}
	170
	171	if (ra->mtu) {
	172	opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu);
	173	iov[msg.msg_iovlen].iov_base = &opt_mtu;
	174	iov[msg.msg_iovlen].iov_len = sizeof(opt_mtu);
	175	msg.msg_iovlen++;
	176	}
	177
	178	LIST_FOREACH(prefix, p, ra->prefixes) {
d601b566 PF	179	if (p->valid_until) {
	180
	181	if (time_now > p->valid_until)
	182	p->opt.valid_lifetime = 0;
	183	else
	184	p->opt.valid_lifetime = htobe32((p->valid_until - time_now) / USEC_PER_SEC);
	185
	186	if (time_now > p->preferred_until)
	187	p->opt.preferred_lifetime = 0;
	188	else
	189	p->opt.preferred_lifetime = htobe32((p->preferred_until - time_now) / USEC_PER_SEC);
	190	}
77baf5ae PF	191	iov[msg.msg_iovlen].iov_base = &p->opt;
	192	iov[msg.msg_iovlen].iov_len = sizeof(p->opt);
	193	msg.msg_iovlen++;
	194	}
	195
e9c6da38 PF	196	if (ra->rdnss) {
	197	iov[msg.msg_iovlen].iov_base = ra->rdnss;
	198	iov[msg.msg_iovlen].iov_len = ra->rdnss->length * 8;
	199	msg.msg_iovlen++;
	200	}
	201
e965d6ab PF	202	if (ra->dnssl) {
	203	iov[msg.msg_iovlen].iov_base = ra->dnssl;
	204	iov[msg.msg_iovlen].iov_len = ra->dnssl->length * 8;
	205	msg.msg_iovlen++;
	206	}
	207
77baf5ae PF	208	if (sendmsg(ra->fd, &msg, 0) < 0)
77baf5ae PF	209	return -errno;
204fb681	210
77baf5ae	211	return 0;
204fb681 PF	212	}
204fb681 PF	213
88d5a3db PF	214	static int radv_recv(sd_event_source s, int fd, uint32_t revents, void userdata) {
	215	sd_radv *ra = userdata;
	216	_cleanup_free_ char *addr = NULL;
	217	struct in6_addr src;
	218	triple_timestamp timestamp;
	219	int r;
	220	ssize_t buflen;
	221	_cleanup_free_ char *buf = NULL;
	222
	223	assert(s);
	224	assert(ra);
	225	assert(ra->event);
	226
	227	buflen = next_datagram_size_fd(fd);
	228
	229	if ((unsigned) buflen < sizeof(struct nd_router_solicit))
	230	return log_radv("Too short packet received");
	231
	232	buf = new0(char, buflen);
	233	if (!buf)
	234	return 0;
	235
	236	r = icmp6_receive(fd, buf, buflen, &src, &timestamp);
	237	if (r < 0) {
	238	switch (r) {
	239	case -EADDRNOTAVAIL:
	240	(void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr);
	241	log_radv("Received RS from non-link-local address %s. Ignoring", addr);
	242	break;
	243
	244	case -EMULTIHOP:
	245	log_radv("Received RS with invalid hop limit. Ignoring.");
	246	break;
	247
	248	case -EPFNOSUPPORT:
	249	log_radv("Received invalid source address from ICMPv6 socket. Ignoring.");
	250	break;
	251
8eb41f4c LP	252	case -EAGAIN: /* ignore spurious wakeups */
	253	break;
	254
88d5a3db	255	default:
8eb41f4c	256	log_radv_errno(r, "Unexpected error receiving from ICMPv6 socket: %m");
88d5a3db PF	257	break;
	258	}
	259
	260	return 0;
	261	}
	262
	263	(void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr);
	264
	265	r = radv_send(ra, &src, ra->lifetime);
	266	if (r < 0)
fdc2afc1	267	log_radv_errno(r, "Unable to send solicited Router Advertisement to %s: %m", addr);
88d5a3db PF	268	else
	269	log_radv("Sent solicited Router Advertisement to %s", addr);
	270
	271	return 0;
	272	}
	273
204fb681 PF	274	static usec_t radv_compute_timeout(usec_t min, usec_t max) {
	275	assert_return(min <= max, SD_RADV_DEFAULT_MIN_TIMEOUT_USEC);
	276
	277	return min + (random_u32() % (max - min));
	278	}
	279
	280	static int radv_timeout(sd_event_source s, uint64_t usec, void userdata) {
	281	int r;
	282	sd_radv *ra = userdata;
	283	usec_t min_timeout = SD_RADV_DEFAULT_MIN_TIMEOUT_USEC;
	284	usec_t max_timeout = SD_RADV_DEFAULT_MAX_TIMEOUT_USEC;
	285	usec_t time_now, timeout;
	286	char time_string[FORMAT_TIMESPAN_MAX];
	287
	288	assert(s);
	289	assert(ra);
	290	assert(ra->event);
	291
	292	ra->timeout_event_source = sd_event_source_unref(ra->timeout_event_source);
	293
	294	r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
	295	if (r < 0)
	296	goto fail;
	297
	298	r = radv_send(ra, NULL, ra->lifetime);
	299	if (r < 0)
fdc2afc1	300	log_radv_errno(r, "Unable to send Router Advertisement: %m");
204fb681 PF	301
	302	/* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
	303	if (ra->ra_sent < SD_RADV_MAX_INITIAL_RTR_ADVERTISEMENTS) {
	304	max_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
	305	min_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC / 3;
	306	}
	307
	308	timeout = radv_compute_timeout(min_timeout, max_timeout);
	309
	310	log_radv("Next Router Advertisement in %s",
	311	format_timespan(time_string, FORMAT_TIMESPAN_MAX,
	312	timeout, USEC_PER_SEC));
	313
	314	r = sd_event_add_time(ra->event, &ra->timeout_event_source,
	315	clock_boottime_or_monotonic(),
	316	time_now + timeout, MSEC_PER_SEC,
	317	radv_timeout, ra);
	318	if (r < 0)
	319	goto fail;
	320
	321	r = sd_event_source_set_priority(ra->timeout_event_source,
	322	ra->event_priority);
	323	if (r < 0)
	324	goto fail;
	325
	326	r = sd_event_source_set_description(ra->timeout_event_source,
	327	"radv-timeout");
	328	if (r < 0)
	329	goto fail;
	330
	331	ra->ra_sent++;
	332
	333	fail:
	334	if (r < 0)
	335	sd_radv_stop(ra);
	336
	337	return 0;
	338	}
	339
204f99d2	340	_public_ int sd_radv_stop(sd_radv *ra) {
204fb681 PF	341	int r;
204fb681 PF	342
204f99d2 PF	343	assert_return(ra, -EINVAL);
204f99d2 PF	344
6f8a8b84 SS	345	if (ra->state == SD_RADV_STATE_IDLE)
	346	return 0;
	347
204f99d2 PF	348	log_radv("Stopping IPv6 Router Advertisement daemon");
204f99d2 PF	349
204fb681 PF	350	/* RFC 4861, Section 6.2.5, send at least one Router Advertisement
	351	with zero lifetime */
	352	r = radv_send(ra, NULL, 0);
	353	if (r < 0)
fdc2afc1	354	log_radv_errno(r, "Unable to send last Router Advertisement with router lifetime set to zero: %m");
204fb681 PF	355
204fb681 PF	356	radv_reset(ra);
77baf5ae	357	ra->fd = safe_close(ra->fd);
204f99d2 PF	358	ra->state = SD_RADV_STATE_IDLE;
	359
	360	return 0;
	361	}
	362
	363	_public_ int sd_radv_start(sd_radv *ra) {
204fb681 PF	364	int r = 0;
204fb681 PF	365
204f99d2 PF	366	assert_return(ra, -EINVAL);
	367	assert_return(ra->event, -EINVAL);
	368	assert_return(ra->ifindex > 0, -EINVAL);
	369
	370	if (ra->state != SD_RADV_STATE_IDLE)
	371	return 0;
	372
204fb681 PF	373	r = sd_event_add_time(ra->event, &ra->timeout_event_source,
	374	clock_boottime_or_monotonic(), 0, 0,
	375	radv_timeout, ra);
	376	if (r < 0)
	377	goto fail;
	378
	379	r = sd_event_source_set_priority(ra->timeout_event_source,
	380	ra->event_priority);
	381	if (r < 0)
	382	goto fail;
	383
	384	(void) sd_event_source_set_description(ra->timeout_event_source,
	385	"radv-timeout");
	386
77baf5ae PF	387	r = icmp6_bind_router_advertisement(ra->ifindex);
	388	if (r < 0)
	389	goto fail;
	390
	391	ra->fd = r;
88d5a3db PF	392
	393	r = sd_event_add_io(ra->event, &ra->recv_event_source, ra->fd, EPOLLIN, radv_recv, ra);
	394	if (r < 0)
	395	goto fail;
	396
	397	r = sd_event_source_set_priority(ra->recv_event_source, ra->event_priority);
	398	if (r < 0)
	399	goto fail;
	400
	401	(void) sd_event_source_set_description(ra->recv_event_source, "radv-receive-message");
77baf5ae	402
204f99d2 PF	403	ra->state = SD_RADV_STATE_ADVERTISING;
	404
	405	log_radv("Started IPv6 Router Advertisement daemon");
	406
	407	return 0;
204fb681 PF	408
	409	fail:
	410	radv_reset(ra);
	411
	412	return r;
204f99d2 PF	413	}
	414
	415	_public_ int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
	416	assert_return(ra, -EINVAL);
	417	assert_return(ifindex >= -1, -EINVAL);
	418
	419	if (ra->state != SD_RADV_STATE_IDLE)
	420	return -EBUSY;
	421
	422	ra->ifindex = ifindex;
	423
	424	return 0;
	425	}
	426
	427	_public_ int sd_radv_set_mac(sd_radv ra, const struct ether_addr mac_addr) {
	428	assert_return(ra, -EINVAL);
	429
	430	if (ra->state != SD_RADV_STATE_IDLE)
	431	return -EBUSY;
	432
	433	if (mac_addr)
	434	ra->mac_addr = *mac_addr;
	435	else
	436	zero(ra->mac_addr);
	437
	438	return 0;
	439	}
	440
	441	_public_ int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
	442	assert_return(ra, -EINVAL);
	443	assert_return(mtu >= 1280, -EINVAL);
	444
204f99d2 PF	445	ra->mtu = mtu;
	446
	447	return 0;
	448	}
	449
	450	_public_ int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
	451	assert_return(ra, -EINVAL);
	452
	453	if (ra->state != SD_RADV_STATE_IDLE)
	454	return -EBUSY;
	455
	456	ra->hop_limit = hop_limit;
	457
	458	return 0;
	459	}
	460
	461	_public_ int sd_radv_set_router_lifetime(sd_radv *ra, uint32_t router_lifetime) {
	462	assert_return(ra, -EINVAL);
	463
	464	if (ra->state != SD_RADV_STATE_IDLE)
	465	return -EBUSY;
	466
	467	/* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the
	468	preference value MUST be set to (00) by the sender..." */
	469	if (router_lifetime == 0 &&
	470	(ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
	471	return -ETIME;
	472
	473	ra->lifetime = router_lifetime;
	474
	475	return 0;
	476	}
	477
	478	_public_ int sd_radv_set_managed_information(sd_radv *ra, int managed) {
	479	assert_return(ra, -EINVAL);
	480
	481	if (ra->state != SD_RADV_STATE_IDLE)
	482	return -EBUSY;
	483
	484	SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
	485
	486	return 0;
	487	}
	488
	489	_public_ int sd_radv_set_other_information(sd_radv *ra, int other) {
	490	assert_return(ra, -EINVAL);
	491
	492	if (ra->state != SD_RADV_STATE_IDLE)
	493	return -EBUSY;
	494
	495	SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
	496
	497	return 0;
	498	}
	499
	500	_public_ int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
	501	int r = 0;
	502
	503	assert_return(ra, -EINVAL);
	504	assert_return(IN_SET(preference,
	505	SD_NDISC_PREFERENCE_LOW,
	506	SD_NDISC_PREFERENCE_MEDIUM,
	507	SD_NDISC_PREFERENCE_HIGH), -EINVAL);
	508
509	ra->flags = (ra->flags & ~(0x3 << 3)) \| (preference << 3);
510
511	return r;
512	}
513
d601b566	514	_public_ int sd_radv_add_prefix(sd_radv ra, sd_radv_prefix p, bool dynamic) {
204f99d2	515	sd_radv_prefix *cur;
d601b566	516	int r;
204f99d2	517	_cleanup_free_ char *addr_p = NULL;
d601b566 PF	518	char time_string_preferred[FORMAT_TIMESPAN_MAX];
	519	char time_string_valid[FORMAT_TIMESPAN_MAX];
	520	usec_t time_now, valid, preferred, valid_until, preferred_until;
204f99d2 PF	521
	522	assert_return(ra, -EINVAL);
	523
	524	if (!p)
	525	return -EINVAL;
	526
	527	LIST_FOREACH(prefix, cur, ra->prefixes) {
204f99d2 PF	528
	529	r = in_addr_prefix_intersect(AF_INET6,
	530	(union in_addr_union*) &cur->opt.in6_addr,
	531	cur->opt.prefixlen,
	532	(union in_addr_union*) &p->opt.in6_addr,
	533	p->opt.prefixlen);
	534	if (r > 0) {
	535	_cleanup_free_ char *addr_cur = NULL;
	536
204f99d2 PF	537	(void) in_addr_to_string(AF_INET6,
	538	(union in_addr_union*) &p->opt.in6_addr,
	539	&addr_p);
	540
d601b566 PF	541	if (dynamic && cur->opt.prefixlen == p->opt.prefixlen)
	542	goto update;
	543
	544	(void) in_addr_to_string(AF_INET6,
	545	(union in_addr_union*) &cur->opt.in6_addr,
	546	&addr_cur);
204f99d2 PF	547	log_radv("IPv6 prefix %s/%u already configured, ignoring %s/%u",
	548	addr_cur, cur->opt.prefixlen,
	549	addr_p, p->opt.prefixlen);
	550
	551	return -EEXIST;
	552	}
	553	}
	554
	555	p = sd_radv_prefix_ref(p);
	556
	557	LIST_APPEND(prefix, ra->prefixes, p);
	558
	559	ra->n_prefixes++;
	560
	561	(void) in_addr_to_string(AF_INET6, (union in_addr_union*) &p->opt.in6_addr, &addr_p);
d601b566 PF	562
	563	if (!dynamic) {
	564	log_radv("Added prefix %s/%d", addr_p, p->opt.prefixlen);
	565	return 0;
	566	}
	567
	568	cur = p;
	569
	570	update:
	571	r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
	572	if (r < 0)
	573	return r;
	574
	575	valid = be32toh(p->opt.valid_lifetime) * USEC_PER_SEC;
	576	valid_until = usec_add(valid, time_now);
	577	if (valid_until == USEC_INFINITY)
	578	return -EOVERFLOW;
	579
	580	preferred = be32toh(p->opt.preferred_lifetime) * USEC_PER_SEC;
	581	preferred_until = usec_add(preferred, time_now);
	582	if (preferred_until == USEC_INFINITY)
	583	return -EOVERFLOW;
	584
	585	cur->valid_until = valid_until;
	586	cur->preferred_until = preferred_until;
	587
	588	log_radv("%s prefix %s/%u preferred %s valid %s",
	589	cur? "Updated": "Added",
	590	addr_p, p->opt.prefixlen,
	591	format_timespan(time_string_preferred, FORMAT_TIMESPAN_MAX,
	592	preferred, USEC_PER_SEC),
	593	format_timespan(time_string_valid, FORMAT_TIMESPAN_MAX,
	594	valid, USEC_PER_SEC));
204f99d2 PF	595
	596	return 0;
	597	}
	598
34c169c4	599	_public_ sd_radv_prefix sd_radv_remove_prefix(sd_radv ra,
f5a5706a LP	600	const struct in6_addr *prefix,
f5a5706a LP	601	unsigned char prefixlen) {
34c169c4 PF	602	sd_radv_prefix cur, next;
	603
	604	assert_return(ra, NULL);
	605	assert_return(prefix, NULL);
	606
	607	LIST_FOREACH_SAFE(prefix, cur, next, ra->prefixes) {
	608	if (prefixlen != cur->opt.prefixlen)
	609	continue;
	610
	611	if (!in_addr_equal(AF_INET6,
	612	(union in_addr_union *)prefix,
	613	(union in_addr_union *)&cur->opt.in6_addr))
	614	continue;
	615
	616	LIST_REMOVE(prefix, ra->prefixes, cur);
	617	ra->n_prefixes--;
	618
	619	break;
	620	}
	621
	622	return cur;
	623	}
	624
e9c6da38 PF	625	_public_ int sd_radv_set_rdnss(sd_radv *ra, uint32_t lifetime,
	626	const struct in6_addr *dns, size_t n_dns) {
	627	_cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
	628	size_t len;
	629
	630	assert_return(ra, -EINVAL);
	631	assert_return(n_dns < 128, -EINVAL);
	632
	633	if (!dns \|\| n_dns == 0) {
	634	ra->rdnss = mfree(ra->rdnss);
	635	ra->n_rdnss = 0;
	636
	637	return 0;
	638	}
	639
	640	len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
	641
	642	opt_rdnss = malloc0(len);
	643	if (!opt_rdnss)
	644	return -ENOMEM;
	645
	646	opt_rdnss->type = SD_RADV_OPT_RDNSS;
	647	opt_rdnss->length = len / 8;
	648	opt_rdnss->lifetime = htobe32(lifetime);
	649
	650	memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
	651
1cc6c93a	652	free_and_replace(ra->rdnss, opt_rdnss);
e9c6da38 PF	653
	654	ra->n_rdnss = n_dns;
	655
	656	return 0;
	657	}
	658
e965d6ab PF	659	_public_ int sd_radv_set_dnssl(sd_radv *ra, uint32_t lifetime,
	660	char **search_list) {
	661	_cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
	662	size_t len = 0;
	663	char **s;
	664	uint8_t *p;
	665
	666	assert_return(ra, -EINVAL);
	667
97d7974b	668	if (strv_isempty(search_list)) {
e965d6ab	669	ra->dnssl = mfree(ra->dnssl);
e965d6ab PF	670	return 0;
	671	}
	672
	673	STRV_FOREACH(s, search_list)
	674	len += strlen(*s) + 2;
	675
	676	len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
	677
	678	opt_dnssl = malloc0(len);
	679	if (!opt_dnssl)
	680	return -ENOMEM;
	681
	682	opt_dnssl->type = SD_RADV_OPT_DNSSL;
	683	opt_dnssl->length = len / 8;
	684	opt_dnssl->lifetime = htobe32(lifetime);
	685
	686	p = (uint8_t *)(opt_dnssl + 1);
	687	len -= sizeof(struct sd_radv_opt_dns);
	688
	689	STRV_FOREACH(s, search_list) {
	690	int r;
	691
	692	r = dns_name_to_wire_format(*s, p, len, false);
	693	if (r < 0)
	694	return r;
	695
	696	if (len < (size_t)r)
	697	return -ENOBUFS;
	698
	699	p += r;
	700	len -= r;
	701	}
	702
1cc6c93a	703	free_and_replace(ra->dnssl, opt_dnssl);
e965d6ab PF	704
	705	return 0;
	706	}
	707
04473969 PF	708	_public_ int sd_radv_prefix_new(sd_radv_prefix **ret) {
	709	_cleanup_(sd_radv_prefix_unrefp) sd_radv_prefix *p = NULL;
	710
	711	assert_return(ret, -EINVAL);
	712
	713	p = new0(sd_radv_prefix, 1);
	714	if (!p)
	715	return -ENOMEM;
	716
	717	p->n_ref = 1;
	718
	719	p->opt.type = ND_OPT_PREFIX_INFORMATION;
	720	p->opt.length = (sizeof(p->opt) - 1) /8 + 1;
	721
	722	p->opt.prefixlen = 64;
	723
	724	/* RFC 4861, Section 6.2.1 */
	725	SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, true);
	726	SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, true);
	727	p->opt.preferred_lifetime = htobe32(604800);
	728	p->opt.valid_lifetime = htobe32(2592000);
	729
204f99d2 PF	730	LIST_INIT(prefix, p);
204f99d2 PF	731
1cc6c93a	732	*ret = TAKE_PTR(p);
04473969 PF	733
	734	return 0;
	735	}
	736
8301aa0b	737	DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
04473969	738
f5a5706a	739	_public_ int sd_radv_prefix_set_prefix(sd_radv_prefix p, const struct in6_addr in6_addr,
04473969 PF	740	unsigned char prefixlen) {
	741	assert_return(p, -EINVAL);
	742	assert_return(in6_addr, -EINVAL);
	743
	744	if (prefixlen < 3 \|\| prefixlen > 128)
	745	return -EINVAL;
	746
	747	if (prefixlen > 64)
	748	/* unusual but allowed, log it */
	749	log_radv("Unusual prefix length %d greater than 64", prefixlen);
	750
	751	p->opt.in6_addr = *in6_addr;
	752	p->opt.prefixlen = prefixlen;
	753
	754	return 0;
	755	}
	756
	757	_public_ int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
	758	assert_return(p, -EINVAL);
	759
	760	SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
	761
	762	return 0;
	763	}
	764
	765	_public_ int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p,
	766	int address_autoconfiguration) {
	767	assert_return(p, -EINVAL);
	768
	769	SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
	770
	771	return 0;
	772	}
	773
	774	_public_ int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p,
	775	uint32_t valid_lifetime) {
	776	assert_return(p, -EINVAL);
	777
	778	p->opt.valid_lifetime = htobe32(valid_lifetime);
	779
	780	return 0;
	781	}
	782
	783	_public_ int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p,
	784	uint32_t preferred_lifetime) {
	785	assert_return(p, -EINVAL);
	786
	787	p->opt.preferred_lifetime = htobe32(preferred_lifetime);
	788
	789	return 0;
	790	}