/*      $KAME: if.c,v 1.17 2001/01/21 15:27:30 itojun Exp $     */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * Copyright (C) 2011 Hiroki Sato <hrs@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/ethernet.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet6/nd6.h>
#include <unistd.h>
#include <errno.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>

#include "pathnames.h"
#include "rtadvd.h"
#include "if.h"

#define ROUNDUP(a, size)                                        \
        (((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))

#define NEXT_SA(ap)                                                     \
        (ap) = (struct sockaddr *)((caddr_t)(ap) +                      \
            ((ap)->sa_len ? ROUNDUP((ap)->sa_len, sizeof(u_long)) :     \
            sizeof(u_long)))

struct sockaddr_in6 sin6_linklocal_allnodes = {
        .sin6_len =     sizeof(sin6_linklocal_allnodes),
        .sin6_family =  AF_INET6,
        .sin6_addr =    IN6ADDR_LINKLOCAL_ALLNODES_INIT,
};

struct sockaddr_in6 sin6_linklocal_allrouters = {
        .sin6_len =     sizeof(sin6_linklocal_allrouters),
        .sin6_family =  AF_INET6,
        .sin6_addr =    IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
};

struct sockaddr_in6 sin6_sitelocal_allrouters = {
        .sin6_len =     sizeof(sin6_sitelocal_allrouters),
        .sin6_family =  AF_INET6,
        .sin6_addr =    IN6ADDR_SITELOCAL_ALLROUTERS_INIT,
};

struct sockinfo sock = { .si_fd = -1, .si_name = NULL };
struct sockinfo rtsock = { .si_fd = -1, .si_name = NULL };
struct sockinfo ctrlsock = { .si_fd = -1, .si_name = _PATH_CTRL_SOCK };

char *mcastif;

static void             get_rtaddrs(int, struct sockaddr *,
                            struct sockaddr **);
static struct if_msghdr *get_next_msghdr(struct if_msghdr *,
                            struct if_msghdr *);

static void
get_rtaddrs(int addrs, struct sockaddr *sa, struct sockaddr **rti_info)
{
        int i;

        for (i = 0; i < RTAX_MAX; i++) {
                if (addrs & (1 << i)) {
                        rti_info[i] = sa;
                        NEXT_SA(sa);
                }
                else
                        rti_info[i] = NULL;
        }
}

#define ROUNDUP8(a) (1 + (((a) - 1) | 7))
int
lladdropt_length(struct sockaddr_dl *sdl)
{
        switch (sdl->sdl_type) {
        case IFT_ETHER:
        case IFT_L2VLAN:
        case IFT_BRIDGE:
                return (ROUNDUP8(ETHER_ADDR_LEN + 2));
        default:
                return (0);
        }
}

void
lladdropt_fill(struct sockaddr_dl *sdl, struct nd_opt_hdr *ndopt)
{
        char *addr;

        ndopt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; /* fixed */

        switch (sdl->sdl_type) {
        case IFT_ETHER:
        case IFT_L2VLAN:
        case IFT_BRIDGE:
                ndopt->nd_opt_len = (ROUNDUP8(ETHER_ADDR_LEN + 2)) >> 3;
                addr = (char *)(ndopt + 1);
                memcpy(addr, LLADDR(sdl), ETHER_ADDR_LEN);
                break;
        default:
                syslog(LOG_ERR, "<%s> unsupported link type(%d)",
                    __func__, sdl->sdl_type);
                exit(1);
        }
}

int
rtbuf_len(void)
{
        size_t len;
        int mib[6] = {CTL_NET, AF_ROUTE, 0, AF_INET6, NET_RT_DUMP, 0};

        if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
                return (-1);

        return (len);
}

#define FILTER_MATCH(type, filter) ((0x1 << type) & filter)
#define SIN6(s) ((struct sockaddr_in6 *)(s))
#define SDL(s) ((struct sockaddr_dl *)(s))
char *
get_next_msg(char *buf, char *lim, int ifindex, size_t *lenp, int filter)
{
        struct rt_msghdr *rtm;
        struct ifa_msghdr *ifam;
        struct sockaddr *sa, *dst, *gw, *ifa, *rti_info[RTAX_MAX];

        *lenp = 0;
        for (rtm = (struct rt_msghdr *)buf;
             rtm < (struct rt_msghdr *)lim;
             rtm = (struct rt_msghdr *)(((char *)rtm) + rtm->rtm_msglen)) {
                /* just for safety */
                if (!rtm->rtm_msglen) {
                        syslog(LOG_WARNING, "<%s> rtm_msglen is 0 "
                            "(buf=%p lim=%p rtm=%p)", __func__,
                            buf, lim, rtm);
                        break;
                }
                if (((struct rt_msghdr *)buf)->rtm_version != RTM_VERSION) {
                        syslog(LOG_WARNING,
                            "<%s> routing message version mismatch "
                            "(buf=%p lim=%p rtm=%p)", __func__,
                            buf, lim, rtm);
                        continue;
                }

                if (FILTER_MATCH(rtm->rtm_type, filter) == 0)
                        continue;

                switch (rtm->rtm_type) {
                case RTM_GET:
                case RTM_ADD:
                case RTM_DELETE:
                        /* address related checks */
                        sa = (struct sockaddr *)(rtm + 1);
                        get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
                        if ((dst = rti_info[RTAX_DST]) == NULL ||
                            dst->sa_family != AF_INET6)
                                continue;

                        if (IN6_IS_ADDR_LINKLOCAL(&SIN6(dst)->sin6_addr) ||
                            IN6_IS_ADDR_MULTICAST(&SIN6(dst)->sin6_addr))
                                continue;

                        if ((gw = rti_info[RTAX_GATEWAY]) == NULL ||
                            gw->sa_family != AF_LINK)
                                continue;
                        if (ifindex && SDL(gw)->sdl_index != ifindex)
                                continue;

                        if (rti_info[RTAX_NETMASK] == NULL)
                                continue;

                        /* found */
                        *lenp = rtm->rtm_msglen;
                        return (char *)rtm;
                        /* NOTREACHED */
                case RTM_NEWADDR:
                case RTM_DELADDR:
                        ifam = (struct ifa_msghdr *)rtm;

                        /* address related checks */
                        sa = (struct sockaddr *)(ifam + 1);
                        get_rtaddrs(ifam->ifam_addrs, sa, rti_info);
                        if ((ifa = rti_info[RTAX_IFA]) == NULL ||
                            (ifa->sa_family != AF_INET &&
                             ifa->sa_family != AF_INET6))
                                continue;

                        if (ifa->sa_family == AF_INET6 &&
                            (IN6_IS_ADDR_LINKLOCAL(&SIN6(ifa)->sin6_addr) ||
                             IN6_IS_ADDR_MULTICAST(&SIN6(ifa)->sin6_addr)))
                                continue;

                        if (ifindex && ifam->ifam_index != ifindex)
                                continue;

                        /* found */
                        *lenp = ifam->ifam_msglen;
                        return (char *)rtm;
                        /* NOTREACHED */
                case RTM_IFINFO:
                case RTM_IFANNOUNCE:
                        /* found */
                        *lenp = rtm->rtm_msglen;
                        return (char *)rtm;
                        /* NOTREACHED */
                }
        }

        return ((char *)rtm);
}
#undef FILTER_MATCH

struct in6_addr *
get_addr(char *buf)
{
        struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
        struct sockaddr *sa, *rti_info[RTAX_MAX];

        sa = (struct sockaddr *)(rtm + 1);
        get_rtaddrs(rtm->rtm_addrs, sa, rti_info);

        return (&SIN6(rti_info[RTAX_DST])->sin6_addr);
}

int
get_rtm_ifindex(char *buf)
{
        struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
        struct sockaddr *sa, *rti_info[RTAX_MAX];

        sa = (struct sockaddr *)(rtm + 1);
        get_rtaddrs(rtm->rtm_addrs, sa, rti_info);

        return (((struct sockaddr_dl *)rti_info[RTAX_GATEWAY])->sdl_index);
}

int
get_prefixlen(char *buf)
{
        struct rt_msghdr *rtm = (struct rt_msghdr *)buf;
        struct sockaddr *sa, *rti_info[RTAX_MAX];
        char *p, *lim;

        sa = (struct sockaddr *)(rtm + 1);
        get_rtaddrs(rtm->rtm_addrs, sa, rti_info);
        sa = rti_info[RTAX_NETMASK];

        p = (char *)(&SIN6(sa)->sin6_addr);
        lim = (char *)sa + sa->sa_len;
        return prefixlen(p, lim);
}

int
prefixlen(unsigned char *p, unsigned char *lim)
{
        int masklen;

        for (masklen = 0; p < lim; p++) {
                switch (*p) {
                case 0xff:
                        masklen += 8;
                        break;
                case 0xfe:
                        masklen += 7;
                        break;
                case 0xfc:
                        masklen += 6;
                        break;
                case 0xf8:
                        masklen += 5;
                        break;
                case 0xf0:
                        masklen += 4;
                        break;
                case 0xe0:
                        masklen += 3;
                        break;
                case 0xc0:
                        masklen += 2;
                        break;
                case 0x80:
                        masklen += 1;
                        break;
                case 0x00:
                        break;
                default:
                        return (-1);
                }
        }

        return (masklen);
}

struct ifinfo *
update_persist_ifinfo(struct ifilist_head_t *ifi_head, const char *ifname)
{
        struct ifinfo *ifi;
        int ifindex;

        ifi = NULL;
        ifindex = if_nametoindex(ifname);
        TAILQ_FOREACH(ifi, ifi_head, ifi_next) {
                if (ifindex != 0) {
                        if (ifindex == ifi->ifi_ifindex)
                                break;
                } else {
                        if (strncmp(ifname, ifi->ifi_ifname,
                                sizeof(ifi->ifi_ifname)) == 0)
                                break;
                }
        }

        if (ifi == NULL) {
                /* A new ifinfo element is needed. */
                syslog(LOG_DEBUG, "<%s> new entry: %s", __func__,
                    ifname);

                ELM_MALLOC(ifi, exit(1));
                ifi->ifi_ifindex = 0;
                strlcpy(ifi->ifi_ifname, ifname, sizeof(ifi->ifi_ifname));
                ifi->ifi_rainfo = NULL;
                ifi->ifi_state = IFI_STATE_UNCONFIGURED;
                TAILQ_INSERT_TAIL(ifi_head, ifi, ifi_next);
        }

        ifi->ifi_persist = 1;

        syslog(LOG_DEBUG, "<%s> %s is marked PERSIST", __func__,
            ifi->ifi_ifname);
        syslog(LOG_DEBUG, "<%s> %s is state = %d", __func__,
            ifi->ifi_ifname, ifi->ifi_state);
        return (ifi);
}

int
update_ifinfo_nd_flags(struct ifinfo *ifi)
{
        struct in6_ndireq nd;
        int s;
        int error;

        if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                syslog(LOG_ERR,
                    "<%s> socket() failed.", __func__);
                return (1);
        }
        /* ND flags */
        memset(&nd, 0, sizeof(nd));
        strlcpy(nd.ifname, ifi->ifi_ifname,
            sizeof(nd.ifname));
        error = ioctl(s, SIOCGIFINFO_IN6, (caddr_t)&nd);
        if (error) {
                close(s);
                if (errno != EPFNOSUPPORT)
                        syslog(LOG_ERR, "<%s> ioctl() failed.", __func__);
                return (1);
        }
        ifi->ifi_nd_flags = nd.ndi.flags;
        close(s);

        return (0);
}

#define MAX_SYSCTL_TRY 5

struct ifinfo *
update_ifinfo(struct ifilist_head_t *ifi_head, int ifindex)
{
        struct if_msghdr *ifm;
        struct ifinfo *ifi = NULL;
        struct sockaddr *sa;
        struct sockaddr *rti_info[RTAX_MAX];
        char *msg;
        size_t len;
        char *lim;
        int mib[] = { CTL_NET, PF_ROUTE, 0, AF_INET6, NET_RT_IFLIST, 0 };
        int error, ntry;

        syslog(LOG_DEBUG, "<%s> enter", __func__);

        ntry = 0;
        do {
                /*
                 * We'll try to get addresses several times in case that
                 * the number of addresses is unexpectedly increased during
                 * the two sysctl calls.  This should rarely happen.
                 * Portability note: since FreeBSD does not add margin of
                 * memory at the first sysctl, the possibility of failure on
                 * the second sysctl call is a bit higher.
                 */

                if (sysctl(mib, nitems(mib), NULL, &len, NULL, 0) < 0) {
                        syslog(LOG_ERR,
                            "<%s> sysctl: NET_RT_IFLIST size get failed",
                            __func__);
                        exit(1);
                }
                if ((msg = malloc(len)) == NULL) {
                        syslog(LOG_ERR, "<%s> malloc failed", __func__);
                        exit(1);
                }
                if (sysctl(mib, nitems(mib), msg, &len, NULL, 0) < 0) {
                        if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
                                free(msg);
                                syslog(LOG_ERR,
                                    "<%s> sysctl: NET_RT_IFLIST get failed",
                                    __func__);
                                exit(1);
                        }
                        free(msg);
                        msg = NULL;
                }
        } while (msg == NULL);

        lim = msg + len;
        for (ifm = (struct if_msghdr *)msg;
             ifm != NULL && ifm < (struct if_msghdr *)lim;
             ifm = get_next_msghdr(ifm,(struct if_msghdr *)lim)) {
                int ifi_new;

                syslog(LOG_DEBUG, "<%s> ifm = %p, lim = %p, diff = %zu",
                    __func__, ifm, lim, (char *)lim - (char *)ifm);

                if (ifm->ifm_version != RTM_VERSION) {
                        syslog(LOG_ERR,
                            "<%s> ifm_vesrion mismatch", __func__);
                        exit(1);
                }
                if (ifm->ifm_msglen == 0) {
                        syslog(LOG_WARNING,
                            "<%s> ifm_msglen is 0", __func__);
                        free(msg);
                        return (NULL);
                }

                ifi_new = 0;
                if (ifm->ifm_type == RTM_IFINFO) {
                        struct ifreq ifr;
                        int s;
                        char ifname[IFNAMSIZ];

                        syslog(LOG_DEBUG, "<%s> RTM_IFINFO found. "
                            "ifm_index = %d, ifindex = %d",
                            __func__, ifm->ifm_index, ifindex);

                        /* when ifindex is specified */
                        if (ifindex != UPDATE_IFINFO_ALL &&
                            ifindex != ifm->ifm_index)
                                continue;

                        /* ifname */
                        if (if_indextoname(ifm->ifm_index, ifname) == NULL) {
                                syslog(LOG_WARNING,
                                    "<%s> ifname not found (idx=%d)",
                                    __func__, ifm->ifm_index);
                                continue;
                        }

                        /* lookup an entry with the same ifindex */
                        TAILQ_FOREACH(ifi, ifi_head, ifi_next) {
                                if (ifm->ifm_index == ifi->ifi_ifindex)
                                        break;
                                if (strncmp(ifname, ifi->ifi_ifname,
                                        sizeof(ifname)) == 0)
                                        break;
                        }
                        if (ifi == NULL) {
                                syslog(LOG_DEBUG,
                                    "<%s> new entry for idx=%d",
                                    __func__, ifm->ifm_index);
                                ELM_MALLOC(ifi, exit(1));
                                ifi->ifi_rainfo = NULL;
                                ifi->ifi_state = IFI_STATE_UNCONFIGURED;
                                ifi->ifi_persist = 0;
                                ifi_new = 1;
                        }
                        /* ifindex */
                        ifi->ifi_ifindex = ifm->ifm_index;

                        /* ifname */
                        strlcpy(ifi->ifi_ifname, ifname, IFNAMSIZ);

                        if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                                syslog(LOG_ERR,
                                    "<%s> socket() failed.", __func__);
                                if (ifi_new)
                                        free(ifi);
                                continue;
                        }

                        /* MTU  */
                        ifi->ifi_phymtu = ifm->ifm_data.ifi_mtu;
                        if (ifi->ifi_phymtu == 0) {
                                memset(&ifr, 0, sizeof(ifr));
                                ifr.ifr_addr.sa_family = AF_INET6;
                                strlcpy(ifr.ifr_name, ifi->ifi_ifname,
                                    sizeof(ifr.ifr_name));
                                error = ioctl(s, SIOCGIFMTU, (caddr_t)&ifr);
                                if (error) {
                                        close(s);
                                        syslog(LOG_ERR,
                                            "<%s> ioctl() failed.",
                                            __func__);
                                        if (ifi_new)
                                                free(ifi);
                                        continue;
                                }
                                ifi->ifi_phymtu = ifr.ifr_mtu;
                                if (ifi->ifi_phymtu == 0) {
                                        syslog(LOG_WARNING,
                                            "<%s> no interface mtu info"
                                            " on %s.  %d will be used.",
                                            __func__, ifi->ifi_ifname,
                                            IPV6_MMTU);
                                        ifi->ifi_phymtu = IPV6_MMTU;
                                }
                        }
                        close(s);

                        /* ND flags */
                        error = update_ifinfo_nd_flags(ifi);
                        if (error) {
                                if (ifi_new)
                                        free(ifi);
                                continue;
                        }

                        /* SDL */
                        sa = (struct sockaddr *)(ifm + 1);
                        get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
                        if ((sa = rti_info[RTAX_IFP]) != NULL) {
                                if (sa->sa_family == AF_LINK) {
                                        memcpy(&ifi->ifi_sdl,
                                            (struct sockaddr_dl *)sa,
                                            sizeof(ifi->ifi_sdl));
                                }
                        } else
                                memset(&ifi->ifi_sdl, 0,
                                    sizeof(ifi->ifi_sdl));

                        /* flags */
                        ifi->ifi_flags = ifm->ifm_flags;

                        /* type */
                        ifi->ifi_type = ifm->ifm_type;
                } else {
                        syslog(LOG_ERR,
                            "out of sync parsing NET_RT_IFLIST\n"
                            "expected %d, got %d\n msglen = %d\n",
                            RTM_IFINFO, ifm->ifm_type, ifm->ifm_msglen);
                        exit(1);
                }

                if (ifi_new) {
                        syslog(LOG_DEBUG,
                            "<%s> adding %s(idx=%d) to ifilist",
                            __func__, ifi->ifi_ifname, ifi->ifi_ifindex);
                        TAILQ_INSERT_TAIL(ifi_head, ifi, ifi_next);
                }
        }
        free(msg);

        if (mcastif != NULL) {
                error = sock_mc_rr_update(&sock, mcastif);
                if (error)
                        exit(1);
        }

        return (ifi);
}

static struct if_msghdr *
get_next_msghdr(struct if_msghdr *ifm, struct if_msghdr *lim)
{
        struct ifa_msghdr *ifam;

        for (ifam = (struct ifa_msghdr *)((char *)ifm + ifm->ifm_msglen);
             ifam < (struct ifa_msghdr *)lim;
             ifam = (struct ifa_msghdr *)((char *)ifam + ifam->ifam_msglen)) {
                if (!ifam->ifam_msglen) {
                        syslog(LOG_WARNING,
                            "<%s> ifa_msglen is 0", __func__);
                        return (NULL);
                }
                if (ifam->ifam_type != RTM_NEWADDR)
                        break;
        }

        return ((struct if_msghdr *)ifam);
}

int
getinet6sysctl(int code)
{
        int mib[] = { CTL_NET, PF_INET6, IPPROTO_IPV6, 0 };
        int value;
        size_t size;

        mib[3] = code;
        size = sizeof(value);
        if (sysctl(mib, nitems(mib), &value, &size, NULL, 0)
            < 0) {
                syslog(LOG_ERR, "<%s>: failed to get ip6 sysctl(%d): %s",
                    __func__, code,
                    strerror(errno));
                return (-1);
        }
        else
                return (value);
}


int
sock_mc_join(struct sockinfo *s, int ifindex)
{
        struct ipv6_mreq mreq;
        char ifname[IFNAMSIZ];

        syslog(LOG_DEBUG, "<%s> enter", __func__);

        if (ifindex == 0)
                return (1);

        /*
         * join all routers multicast address on each advertising
         * interface.
         */
        memset(&mreq, 0, sizeof(mreq));
        /* XXX */
        memcpy(&mreq.ipv6mr_multiaddr.s6_addr,
            &sin6_linklocal_allrouters.sin6_addr,
            sizeof(mreq.ipv6mr_multiaddr.s6_addr));

        mreq.ipv6mr_interface = ifindex;
        if (setsockopt(s->si_fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq,
                sizeof(mreq)) < 0) {
                syslog(LOG_ERR,
                    "<%s> IPV6_JOIN_GROUP(link) on %s: %s",
                    __func__, if_indextoname(ifindex, ifname),
                    strerror(errno));
                return (1);
        }
        syslog(LOG_DEBUG,
            "<%s> %s: join link-local all-routers MC group",
            __func__, if_indextoname(ifindex, ifname));

        return (0);
}

int
sock_mc_leave(struct sockinfo *s, int ifindex)
{
        struct ipv6_mreq mreq;
        char ifname[IFNAMSIZ];

        syslog(LOG_DEBUG, "<%s> enter", __func__);

        if (ifindex == 0)
                return (1);

        /*
         * join all routers multicast address on each advertising
         * interface.
         */

        memset(&mreq, 0, sizeof(mreq));
        /* XXX */
        memcpy(&mreq.ipv6mr_multiaddr.s6_addr,
            &sin6_linklocal_allrouters.sin6_addr,
            sizeof(mreq.ipv6mr_multiaddr.s6_addr));

        mreq.ipv6mr_interface = ifindex;
        if (setsockopt(s->si_fd, IPPROTO_IPV6, IPV6_LEAVE_GROUP, &mreq,
                sizeof(mreq)) < 0) {
                syslog(LOG_ERR,
                    "<%s> IPV6_JOIN_LEAVE(link) on %s: %s",
                    __func__, if_indextoname(ifindex, ifname),
                    strerror(errno));
                return (1);
        }
        syslog(LOG_DEBUG,
            "<%s> %s: leave link-local all-routers MC group",
            __func__, if_indextoname(ifindex, ifname));

        return (0);
}

int
sock_mc_rr_update(struct sockinfo *s, char *mif)
{
        struct ipv6_mreq mreq;

        syslog(LOG_DEBUG, "<%s> enter", __func__);

        if (mif == NULL)
                return (1);
        /*
         * When attending router renumbering, join all-routers site-local
         * multicast group.
         */
        /* XXX */
        memcpy(&mreq.ipv6mr_multiaddr.s6_addr,
            &sin6_sitelocal_allrouters.sin6_addr,
            sizeof(mreq.ipv6mr_multiaddr.s6_addr));
        if ((mreq.ipv6mr_interface = if_nametoindex(mif)) == 0) {
                syslog(LOG_ERR,
                    "<%s> invalid interface: %s",
                    __func__, mif);
                return (1);
        }

        if (setsockopt(s->si_fd, IPPROTO_IPV6, IPV6_JOIN_GROUP,
                &mreq, sizeof(mreq)) < 0) {
                syslog(LOG_ERR,
                    "<%s> IPV6_JOIN_GROUP(site) on %s: %s",
                    __func__, mif, strerror(errno));
                return (1);
        }

        syslog(LOG_DEBUG,
            "<%s> %s: join site-local all-routers MC group",
            __func__, mif);

        return (0);
}