/*      $KAME: config.c,v 1.84 2003/08/05 12:34:23 itojun Exp $ */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 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/ioctl.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/route.h>
#include <net/if_dl.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/nd6.h>

#include <arpa/inet.h>

#include <stdio.h>
#include <syslog.h>
#include <errno.h>
#include <inttypes.h>
#include <netdb.h>
#include <string.h>
#include <search.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <ifaddrs.h>

#include "rtadvd.h"
#include "advcap.h"
#include "timer.h"
#include "if.h"
#include "config.h"

/* label of tcapcode + number + domain name + zero octet */
static char entbuf[10 + 3 + NI_MAXHOST + 1];
static char oentbuf[10 + 3 + NI_MAXHOST + 1];
static char abuf[DNAME_LABELENC_MAXLEN];

static time_t prefix_timo = (60 * 120); /* 2 hours.
                                         * XXX: should be configurable. */

static struct rtadvd_timer *prefix_timeout(void *);
static void makeentry(char *, size_t, int, const char *);
static ssize_t dname_labelenc(char *, const char *);

/* Encode domain name label encoding in RFC 1035 Section 3.1 */
static ssize_t
dname_labelenc(char *dst, const char *src)
{
        char *dst_origin;
        char *p;
        size_t len;

        dst_origin = dst;
        len = strlen(src);

        if (len + len / 64 + 1 + 1 > DNAME_LABELENC_MAXLEN)
                return (-1);
        /* Length fields per 63 octets + '\0' (<= DNAME_LABELENC_MAXLEN) */
        memset(dst, 0, len + len / 64 + 1 + 1);

        syslog(LOG_DEBUG, "<%s> labelenc = %s", __func__, src);
        while (src && (len = strlen(src)) != 0) {
                /* Put a length field with 63 octet limitation first. */
                p = strchr(src, '.');
                if (p == NULL)
                        *dst = len = MIN(63, len);
                else
                        *dst = len = MIN(63, p - src);
                if (dst + 1 + len < dst_origin + DNAME_LABELENC_MAXLEN)
                        dst++;
                else
                        return (-1);
                /* Copy 63 octets at most. */
                memcpy(dst, src, len);
                dst += len;
                if (p == NULL) /* the last label */
                        break;
                src = p + 1;
        }
        /* Always need a 0-length label at the tail. */
        *dst++ = '\0';

        syslog(LOG_DEBUG, "<%s> labellen = %td", __func__, dst - dst_origin);
        return (dst - dst_origin);
}

#define MUSTHAVE(var, cap)                                              \
    do {                                                                \
        int64_t t;                                                      \
        if ((t = agetnum(cap)) < 0) {                                   \
                fprintf(stderr, "rtadvd: need %s for interface %s\n",   \
                        cap, intface);                                  \
                exit(1);                                                \
        }                                                               \
        var = t;                                                        \
     } while (0)

#define MAYHAVE(var, cap, def)                                          \
     do {                                                               \
        if ((var = agetnum(cap)) < 0)                                   \
                var = def;                                              \
     } while (0)

int
loadconfig_index(int idx)
{
        char ifname[IFNAMSIZ];

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

        if (if_indextoname(idx, ifname) != NULL)
                return (loadconfig_ifname(ifname));
        else
                return (1);
}

int
loadconfig_ifname(char *ifname)
{
        struct ifinfo *ifi;

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

        update_ifinfo(&ifilist, UPDATE_IFINFO_ALL);
        TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
                /* NULL means all IFs will be processed. */
                if (ifname != NULL &&
                    strcmp(ifi->ifi_ifname, ifname) != 0)
                        continue;

                if (!ifi->ifi_persist) {
                        syslog(LOG_INFO,
                            "<%s> %s is not a target interface.  "
                            "Ignored at this moment.", __func__,
                            ifi->ifi_ifname);
                        continue;

                }
                if (ifi->ifi_ifindex == 0) {
                        syslog(LOG_ERR,
                            "<%s> %s not found.  "
                            "Ignored at this moment.", __func__,
                            ifi->ifi_ifname);
                        continue;
                }
                if (getconfig(ifi) == NULL) {
                        syslog(LOG_ERR,
                            "<%s> invalid configuration for %s.  "
                            "Ignored at this moment.", __func__,
                            ifi->ifi_ifname);
                        continue;
                }
        }
        return (0);
}

int
rm_ifinfo_index(int idx)
{
        struct ifinfo *ifi;

        ifi = if_indextoifinfo(idx);
        if (ifi == NULL) {
                syslog(LOG_ERR, "<%s>: ifinfo not found (idx=%d)",
                    __func__, idx);
                return (-1);
        }

        return (rm_ifinfo(ifi));
}

int
rm_ifinfo(struct ifinfo *ifi)
{
        int error;

        syslog(LOG_DEBUG, "<%s> enter (%s).", __func__, ifi->ifi_ifname);
        switch (ifi->ifi_state) {
        case IFI_STATE_UNCONFIGURED:
                return (0);
                break;
        default:
                ifi->ifi_state = IFI_STATE_UNCONFIGURED;
                syslog(LOG_DEBUG,
                    "<%s> ifname=%s marked as UNCONFIGURED.",
                    __func__, ifi->ifi_ifname);

                /* XXX: No MC leaving here because index is disappeared */

                /* Inactivate timer */
                rtadvd_remove_timer(ifi->ifi_ra_timer);
                ifi->ifi_ra_timer = NULL;
                break;
        }

        /* clean up ifi */
        if (!ifi->ifi_persist) {
                TAILQ_REMOVE(&ifilist, ifi, ifi_next);
                syslog(LOG_DEBUG, "<%s>: ifinfo (idx=%d) removed.",
                    __func__, ifi->ifi_ifindex);
        } else {
                /* recreate an empty entry */
                update_persist_ifinfo(&ifilist, ifi->ifi_ifname);
                syslog(LOG_DEBUG, "<%s>: ifname=%s is persistent.",
                    __func__, ifi->ifi_ifname);
        }

        /* clean up rai if any */
        switch (ifi->ifi_state) {
        case IFI_STATE_CONFIGURED:
                if (ifi->ifi_rainfo != NULL) {
                        error = rm_rainfo(ifi->ifi_rainfo);
                        if (error)
                                return (error);
                        ifi->ifi_rainfo = NULL;
                }
                break;
        case IFI_STATE_TRANSITIVE:
                if (ifi->ifi_rainfo == ifi->ifi_rainfo_trans) {
                        if (ifi->ifi_rainfo != NULL) {
                                error = rm_rainfo(ifi->ifi_rainfo);
                                if (error)
                                        return (error);
                                ifi->ifi_rainfo = NULL;
                                ifi->ifi_rainfo_trans = NULL;
                        }
                } else {
                        if (ifi->ifi_rainfo != NULL) {
                                error = rm_rainfo(ifi->ifi_rainfo);
                                if (error)
                                        return (error);
                                ifi->ifi_rainfo = NULL;
                        }
                        if (ifi->ifi_rainfo_trans != NULL) {
                                error = rm_rainfo(ifi->ifi_rainfo_trans);
                                if (error)
                                        return (error);
                                ifi->ifi_rainfo_trans = NULL;
                        }
                }
        }

        syslog(LOG_DEBUG, "<%s> leave (%s).", __func__, ifi->ifi_ifname);
        if (!ifi->ifi_persist)
                free(ifi);
        return (0);
}

int
rm_rainfo(struct rainfo *rai)
{
        struct prefix *pfx;
        struct soliciter *sol;
        struct rdnss *rdn;
        struct rdnss_addr *rdna;
        struct dnssl *dns;
        struct pref64 *prf64;
        struct rtinfo *rti;

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

        TAILQ_REMOVE(&railist, rai, rai_next);
        if (rai->rai_ifinfo != NULL)
                syslog(LOG_DEBUG, "<%s>: rainfo (idx=%d) removed.",
                    __func__, rai->rai_ifinfo->ifi_ifindex);

        if (rai->rai_ra_data != NULL)
                free(rai->rai_ra_data);

        while ((pfx = TAILQ_FIRST(&rai->rai_prefix)) != NULL)
                delete_prefix(pfx);
        while ((sol = TAILQ_FIRST(&rai->rai_soliciter)) != NULL) {
                TAILQ_REMOVE(&rai->rai_soliciter, sol, sol_next);
                free(sol);
        }
        while ((rdn = TAILQ_FIRST(&rai->rai_rdnss)) != NULL) {
                TAILQ_REMOVE(&rai->rai_rdnss, rdn, rd_next);
                while ((rdna = TAILQ_FIRST(&rdn->rd_list)) != NULL) {
                        TAILQ_REMOVE(&rdn->rd_list, rdna, ra_next);
                        free(rdna);
                }
                free(rdn);
        }
        while ((dns = TAILQ_FIRST(&rai->rai_dnssl)) != NULL) {
                TAILQ_REMOVE(&rai->rai_dnssl, dns, dn_next);
                free(dns);
        }
        while ((rti = TAILQ_FIRST(&rai->rai_route)) != NULL) {
                TAILQ_REMOVE(&rai->rai_route, rti, rti_next);
                free(rti);
        }
        while ((prf64 = TAILQ_FIRST(&rai->rai_pref64)) != NULL) {
                TAILQ_REMOVE(&rai->rai_pref64, prf64, p64_next);
                free(prf64);
        }
        free(rai);
        syslog(LOG_DEBUG, "<%s>: leave",  __func__);

        return (0);
}

struct ifinfo *
getconfig(struct ifinfo *ifi)
{
        int stat, i;
        int error;
        char tbuf[BUFSIZ];
        struct rainfo *rai;
        struct rainfo *rai_old;
        int32_t val;
        int64_t val64;
        char buf[BUFSIZ];
        char *bp = buf;
        char *addr, *flagstr;

        if (ifi == NULL)        /* if does not exist */
                return (NULL);

        if (ifi->ifi_state == IFI_STATE_TRANSITIVE &&
            ifi->ifi_rainfo == NULL) {
                syslog(LOG_INFO, "<%s> %s is shutting down.  Skipped.",
                    __func__, ifi->ifi_ifname);
                return (NULL);
        }

        if ((stat = agetent(tbuf, ifi->ifi_ifname)) <= 0) {
                memset(tbuf, 0, sizeof(tbuf));
                syslog(LOG_INFO,
                    "<%s> %s isn't defined in the configuration file"
                    " or the configuration file doesn't exist."
                    " Treat it as default",
                     __func__, ifi->ifi_ifname);
        }

        ELM_MALLOC(rai, exit(1));
        TAILQ_INIT(&rai->rai_prefix);
        TAILQ_INIT(&rai->rai_route);
        TAILQ_INIT(&rai->rai_rdnss);
        TAILQ_INIT(&rai->rai_dnssl);
        TAILQ_INIT(&rai->rai_pref64);
        TAILQ_INIT(&rai->rai_soliciter);
        rai->rai_ifinfo = ifi;

        /* gather on-link prefixes from the network interfaces. */
        if (agetflag("noifprefix"))
                rai->rai_advifprefix = 0;
        else
                rai->rai_advifprefix = 1;

        /* get interface information */
        if (agetflag("nolladdr"))
                rai->rai_advlinkopt = 0;
        else
                rai->rai_advlinkopt = 1;
        if (rai->rai_advlinkopt) {
                if (ifi->ifi_sdl.sdl_type == 0) {
                        syslog(LOG_ERR,
                            "<%s> can't get information of %s",
                            __func__, ifi->ifi_ifname);
                        goto getconfig_free_rai;
                }
        }

        /*
         * set router configuration variables.
         */
        MAYHAVE(val, "maxinterval", DEF_MAXRTRADVINTERVAL);
        if (val < MIN_MAXINTERVAL || val > MAX_MAXINTERVAL) {
                syslog(LOG_ERR,
                    "<%s> maxinterval (%" PRIu32 ") on %s is invalid "
                    "(must be between %u and %u)", __func__, val,
                    ifi->ifi_ifname, MIN_MAXINTERVAL, MAX_MAXINTERVAL);
                goto getconfig_free_rai;
        }
        rai->rai_maxinterval = (uint16_t)val;

        MAYHAVE(val, "mininterval", rai->rai_maxinterval/3);
        if ((uint16_t)val < MIN_MININTERVAL ||
            (uint16_t)val > (rai->rai_maxinterval * 3) / 4) {
                syslog(LOG_ERR,
                    "<%s> mininterval (%" PRIu32 ") on %s is invalid "
                    "(must be between %d and %d)",
                    __func__, val, ifi->ifi_ifname, MIN_MININTERVAL,
                    (rai->rai_maxinterval * 3) / 4);
                goto getconfig_free_rai;
        }
        rai->rai_mininterval = (uint16_t)val;

        MAYHAVE(val, "chlim", DEF_ADVCURHOPLIMIT);
        rai->rai_hoplimit = val & 0xff;

        if ((flagstr = (char *)agetstr("raflags", &bp))) {
                val = 0;
                if (strchr(flagstr, 'm'))
                        val |= ND_RA_FLAG_MANAGED;
                if (strchr(flagstr, 'o'))
                        val |= ND_RA_FLAG_OTHER;
                if (strchr(flagstr, 'h'))
                        val |= ND_RA_FLAG_RTPREF_HIGH;
                if (strchr(flagstr, 'l')) {
                        if ((val & ND_RA_FLAG_RTPREF_HIGH)) {
                                syslog(LOG_ERR, "<%s> the \'h\' and \'l\'"
                                    " router flags are exclusive", __func__);
                                goto getconfig_free_rai;
                        }
                        val |= ND_RA_FLAG_RTPREF_LOW;
                }
#ifdef DRAFT_IETF_6MAN_IPV6ONLY_FLAG
                if (strchr(flagstr, 'S'))
                        val |= ND_RA_FLAG_IPV6_ONLY;
#endif
        } else
                MAYHAVE(val, "raflags", 0);

        rai->rai_managedflg = val & ND_RA_FLAG_MANAGED;
        rai->rai_otherflg = val & ND_RA_FLAG_OTHER;
#ifndef ND_RA_FLAG_RTPREF_MASK
#define ND_RA_FLAG_RTPREF_MASK  0x18 /* 00011000 */
#define ND_RA_FLAG_RTPREF_RSV   0x10 /* 00010000 */
#endif
        rai->rai_rtpref = val & ND_RA_FLAG_RTPREF_MASK;
        if (rai->rai_rtpref == ND_RA_FLAG_RTPREF_RSV) {
                syslog(LOG_ERR, "<%s> invalid router preference (%02x) on %s",
                    __func__, rai->rai_rtpref, ifi->ifi_ifname);
                goto getconfig_free_rai;
        }
#ifdef DRAFT_IETF_6MAN_IPV6ONLY_FLAG
        rai->rai_ipv6onlyflg = val & ND_RA_FLAG_IPV6_ONLY;
#endif

        MAYHAVE(val, "rltime", rai->rai_maxinterval * 3);
        if ((uint16_t)val && ((uint16_t)val < rai->rai_maxinterval ||
            (uint16_t)val > MAXROUTERLIFETIME)) {
                syslog(LOG_ERR,
                    "<%s> router lifetime (%" PRIu32 ") on %s is invalid "
                    "(must be 0 or between %d and %d)",
                    __func__, val, ifi->ifi_ifname, rai->rai_maxinterval,
                    MAXROUTERLIFETIME);
                goto getconfig_free_rai;
        }
        rai->rai_lifetime = val & 0xffff;

        MAYHAVE(val, "rtime", DEF_ADVREACHABLETIME);
        if (val < 0 || val > MAXREACHABLETIME) {
                syslog(LOG_ERR,
                    "<%s> reachable time (%" PRIu32 ") on %s is invalid "
                    "(must be no greater than %d)",
                    __func__, val, ifi->ifi_ifname, MAXREACHABLETIME);
                goto getconfig_free_rai;
        }
        rai->rai_reachabletime = (uint32_t)val;

        MAYHAVE(val64, "retrans", DEF_ADVRETRANSTIMER);
        if (val64 < 0 || val64 > 0xffffffff) {
                syslog(LOG_ERR, "<%s> retrans time (%" PRIu64 ") on %s out of range",
                    __func__, val64, ifi->ifi_ifname);
                goto getconfig_free_rai;
        }
        rai->rai_retranstimer = (uint32_t)val64;

        if (agetnum("hapref") != -1 || agetnum("hatime") != -1) {
                syslog(LOG_ERR,
                    "<%s> mobile-ip6 configuration not supported",
                    __func__);
                goto getconfig_free_rai;
        }
        /* prefix information */

        /*
         * This is an implementation specific parameter to consider
         * link propagation delays and poorly synchronized clocks when
         * checking consistency of advertised lifetimes.
         */
        MAYHAVE(val, "clockskew", 0);
        rai->rai_clockskew = val;

        rai->rai_pfxs = 0;
        for (i = -1; i < MAXPREFIX; i++) {
                struct prefix *pfx;

                makeentry(entbuf, sizeof(entbuf), i, "addr");
                addr = (char *)agetstr(entbuf, &bp);
                if (addr == NULL)
                        continue;

                /* allocate memory to store prefix information */
                ELM_MALLOC(pfx, exit(1));
                pfx->pfx_rainfo = rai;
                pfx->pfx_origin = PREFIX_FROM_CONFIG;

                if (inet_pton(AF_INET6, addr, &pfx->pfx_prefix) != 1) {
                        syslog(LOG_ERR,
                            "<%s> inet_pton failed for %s",
                            __func__, addr);
                        goto getconfig_free_pfx;
                }
                if (IN6_IS_ADDR_MULTICAST(&pfx->pfx_prefix)) {
                        syslog(LOG_ERR,
                            "<%s> multicast prefix (%s) must "
                            "not be advertised on %s",
                            __func__, addr, ifi->ifi_ifname);
                        goto getconfig_free_pfx;
                }
                if (IN6_IS_ADDR_LINKLOCAL(&pfx->pfx_prefix))
                        syslog(LOG_NOTICE,
                            "<%s> link-local prefix (%s) will be"
                            " advertised on %s",
                            __func__, addr, ifi->ifi_ifname);

                makeentry(entbuf, sizeof(entbuf), i, "prefixlen");
                MAYHAVE(val, entbuf, 64);
                if (val < 0 || val > 128) {
                        syslog(LOG_ERR, "<%s> prefixlen (%" PRIu32 ") for %s "
                            "on %s out of range",
                            __func__, val, addr, ifi->ifi_ifname);
                        goto getconfig_free_pfx;
                }
                pfx->pfx_prefixlen = (int)val;

                makeentry(entbuf, sizeof(entbuf), i, "pinfoflags");
                if ((flagstr = (char *)agetstr(entbuf, &bp))) {
                        val = 0;
                        if (strchr(flagstr, 'l'))
                                val |= ND_OPT_PI_FLAG_ONLINK;
                        if (strchr(flagstr, 'a'))
                                val |= ND_OPT_PI_FLAG_AUTO;
                } else {
                        MAYHAVE(val, entbuf,
                            (ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO));
                }
                pfx->pfx_onlinkflg = val & ND_OPT_PI_FLAG_ONLINK;
                pfx->pfx_autoconfflg = val & ND_OPT_PI_FLAG_AUTO;

                makeentry(entbuf, sizeof(entbuf), i, "vltime");
                MAYHAVE(val64, entbuf, DEF_ADVVALIDLIFETIME);
                if (val64 < 0 || val64 > 0xffffffff) {
                        syslog(LOG_ERR, "<%s> vltime (%" PRIu64 ") for "
                            "%s/%d on %s is out of range",
                            __func__, val64,
                            addr, pfx->pfx_prefixlen, ifi->ifi_ifname);
                        goto getconfig_free_pfx;
                }
                pfx->pfx_validlifetime = (uint32_t)val64;

                makeentry(entbuf, sizeof(entbuf), i, "vltimedecr");
                if (agetflag(entbuf)) {
                        struct timespec now;

                        clock_gettime(CLOCK_MONOTONIC_FAST, &now);
                        pfx->pfx_vltimeexpire =
                                now.tv_sec + pfx->pfx_validlifetime;
                }

                makeentry(entbuf, sizeof(entbuf), i, "pltime");
                MAYHAVE(val64, entbuf, DEF_ADVPREFERREDLIFETIME);
                if (val64 < 0 || val64 > 0xffffffff) {
                        syslog(LOG_ERR,
                            "<%s> pltime (%" PRIu64 ") for %s/%d on %s "
                            "is out of range",
                            __func__, val64,
                            addr, pfx->pfx_prefixlen, ifi->ifi_ifname);
                        goto getconfig_free_pfx;
                }
                pfx->pfx_preflifetime = (uint32_t)val64;

                makeentry(entbuf, sizeof(entbuf), i, "pltimedecr");
                if (agetflag(entbuf)) {
                        struct timespec now;

                        clock_gettime(CLOCK_MONOTONIC_FAST, &now);
                        pfx->pfx_pltimeexpire =
                            now.tv_sec + pfx->pfx_preflifetime;
                }
                /* link into chain */
                TAILQ_INSERT_TAIL(&rai->rai_prefix, pfx, pfx_next);
                rai->rai_pfxs++;
                continue;
getconfig_free_pfx:
                free(pfx);
        }
        if (rai->rai_advifprefix && rai->rai_pfxs == 0)
                get_prefix(rai);

        MAYHAVE(val64, "mtu", 0);
        if (val64 < 0 || val64 > 0xffffffff) {
                syslog(LOG_ERR,
                    "<%s> mtu (%" PRIu64 ") on %s out of range",
                    __func__, val64, ifi->ifi_ifname);
                goto getconfig_free_rai;
        }
        rai->rai_linkmtu = (uint32_t)val64;
        if (rai->rai_linkmtu == 0) {
                char *mtustr;

                if ((mtustr = (char *)agetstr("mtu", &bp)) &&
                    strcmp(mtustr, "auto") == 0)
                        rai->rai_linkmtu = ifi->ifi_phymtu;
        }
        else if (rai->rai_linkmtu < IPV6_MMTU ||
            rai->rai_linkmtu > ifi->ifi_phymtu) {
                syslog(LOG_ERR,
                    "<%s> advertised link mtu (%" PRIu32 ") on %s is invalid (must "
                    "be between least MTU (%d) and physical link MTU (%d)",
                    __func__, rai->rai_linkmtu, ifi->ifi_ifname,
                    IPV6_MMTU, ifi->ifi_phymtu);
                goto getconfig_free_rai;
        }

#ifdef SIOCSIFINFO_IN6
        {
                struct in6_ndireq ndi;
                int s;

                if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                        syslog(LOG_ERR, "<%s> socket: %s", __func__,
                            strerror(errno));
                        exit(1);
                }
                memset(&ndi, 0, sizeof(ndi));
                strlcpy(ndi.ifname, ifi->ifi_ifname, sizeof(ndi.ifname));
                if (ioctl(s, SIOCGIFINFO_IN6, (caddr_t)&ndi) < 0)
                        syslog(LOG_INFO, "<%s> ioctl:SIOCGIFINFO_IN6 at %s: %s",
                            __func__, ifi->ifi_ifname, strerror(errno));

                /* reflect the RA info to the host variables in kernel */
                ndi.ndi.chlim = rai->rai_hoplimit;
                ndi.ndi.retrans = rai->rai_retranstimer;
                ndi.ndi.basereachable = rai->rai_reachabletime;
                if (ioctl(s, SIOCSIFINFO_IN6, (caddr_t)&ndi) < 0)
                        syslog(LOG_INFO, "<%s> ioctl:SIOCSIFINFO_IN6 at %s: %s",
                            __func__, ifi->ifi_ifname, strerror(errno));

                close(s);
        }
#endif

        /* route information */
        rai->rai_routes = 0;
        for (i = -1; i < MAXROUTE; i++) {
                struct rtinfo *rti;

                makeentry(entbuf, sizeof(entbuf), i, "rtprefix");
                addr = (char *)agetstr(entbuf, &bp);
                if (addr == NULL) {
                        makeentry(oentbuf, sizeof(oentbuf), i, "rtrprefix");
                        addr = (char *)agetstr(oentbuf, &bp);
                        if (addr)
                                fprintf(stderr, "%s was obsoleted.  Use %s.\n",
                                    oentbuf, entbuf);
                }
                if (addr == NULL)
                        continue;

                /* allocate memory to store prefix information */
                ELM_MALLOC(rti, exit(1));

                if (inet_pton(AF_INET6, addr, &rti->rti_prefix) != 1) {
                        syslog(LOG_ERR, "<%s> inet_pton failed for %s",
                            __func__, addr);
                        goto getconfig_free_rti;
                }
#if 0
                /*
                 * XXX: currently there's no restriction in route information
                 * prefix according to
                 * draft-ietf-ipngwg-router-selection-00.txt.
                 * However, I think the similar restriction be necessary.
                 */
                MAYHAVE(val64, entbuf, DEF_ADVVALIDLIFETIME);
                if (IN6_IS_ADDR_MULTICAST(&rti->prefix)) {
                        syslog(LOG_ERR,
                            "<%s> multicast route (%s) must "
                            "not be advertised on %s",
                            __func__, addr, ifi->ifi_ifname);
                        goto getconfig_free_rti;
                }
                if (IN6_IS_ADDR_LINKLOCAL(&rti->prefix)) {
                        syslog(LOG_NOTICE,
                            "<%s> link-local route (%s) will "
                            "be advertised on %s",
                            __func__, addr, ifi->ifi_ifname);
                        goto getconfig_free_rti;
                }
#endif

                makeentry(entbuf, sizeof(entbuf), i, "rtplen");
                /* XXX: 256 is a magic number for compatibility check. */
                MAYHAVE(val, entbuf, 256);
                if (val == 256) {
                        makeentry(oentbuf, sizeof(oentbuf), i, "rtrplen");
                        MAYHAVE(val, oentbuf, 256);
                        if (val != 256)
                                fprintf(stderr, "%s was obsoleted.  Use %s.\n",
                                    oentbuf, entbuf);
                        else
                                val = 64;
                }
                if (val < 0 || val > 128) {
                        syslog(LOG_ERR, "<%s> prefixlen (%" PRIu32 ") for %s on %s "
                            "out of range",
                            __func__, val, addr, ifi->ifi_ifname);
                        goto getconfig_free_rti;
                }
                rti->rti_prefixlen = (int)val;

                makeentry(entbuf, sizeof(entbuf), i, "rtflags");
                if ((flagstr = (char *)agetstr(entbuf, &bp))) {
                        val = 0;
                        if (strchr(flagstr, 'h'))
                                val |= ND_RA_FLAG_RTPREF_HIGH;
                        if (strchr(flagstr, 'l')) {
                                if ((val & ND_RA_FLAG_RTPREF_HIGH)) {
                                        syslog(LOG_ERR,
                                            "<%s> the \'h\' and \'l\' route"
                                            " preferences are exclusive",
                                            __func__);
                                        goto getconfig_free_rti;
                                }
                                val |= ND_RA_FLAG_RTPREF_LOW;
                        }
                } else
                        MAYHAVE(val, entbuf, 256); /* XXX */
                if (val == 256) {
                        makeentry(oentbuf, sizeof(oentbuf), i, "rtrflags");
                        MAYHAVE(val, oentbuf, 256);
                        if (val != 256) {
                                fprintf(stderr, "%s was obsoleted.  Use %s.\n",
                                    oentbuf, entbuf);
                        } else
                                val = 0;
                }
                rti->rti_rtpref = val & ND_RA_FLAG_RTPREF_MASK;
                if (rti->rti_rtpref == ND_RA_FLAG_RTPREF_RSV) {
                        syslog(LOG_ERR, "<%s> invalid route preference (%02x) "
                            "for %s/%d on %s",
                            __func__, rti->rti_rtpref, addr,
                            rti->rti_prefixlen, ifi->ifi_ifname);
                        goto getconfig_free_rti;
                }

                /*
                 * Since the spec does not a default value, we should make
                 * this entry mandatory.  However, FreeBSD 4.4 has shipped
                 * with this field being optional, we use the router lifetime
                 * as an ad-hoc default value with a warning message.
                 */
                makeentry(entbuf, sizeof(entbuf), i, "rtltime");
                MAYHAVE(val64, entbuf, -1);
                if (val64 == -1) {
                        makeentry(oentbuf, sizeof(oentbuf), i, "rtrltime");
                        MAYHAVE(val64, oentbuf, -1);
                        if (val64 != -1)
                                fprintf(stderr, "%s was obsoleted.  Use %s.\n",
                                    oentbuf, entbuf);
                        else {
                                fprintf(stderr, "%s should be specified "
                                    "for interface %s.\n", entbuf,
                                    ifi->ifi_ifname);
                                val64 = rai->rai_lifetime;
                        }
                }
                if (val64 < 0 || val64 > 0xffffffff) {
                        syslog(LOG_ERR, "<%s> route lifetime (%" PRIu64 ") for "
                            "%s/%d on %s out of range", __func__,
                            val64, addr, rti->rti_prefixlen,
                            ifi->ifi_ifname);
                        goto getconfig_free_rti;
                }
                rti->rti_ltime = (uint32_t)val64;

                /* link into chain */
                TAILQ_INSERT_TAIL(&rai->rai_route, rti, rti_next);
                rai->rai_routes++;
                continue;
getconfig_free_rti:
                free(rti);
        }

        /* DNS server and DNS search list information */
        for (i = -1; i < MAXRDNSSENT ; i++) {
                struct rdnss *rdn;
                struct rdnss_addr *rdna;
                char *ap;
                int c;

                makeentry(entbuf, sizeof(entbuf), i, "rdnss");
                addr = (char *)agetstr(entbuf, &bp);
                if (addr == NULL)
                        continue;
                ELM_MALLOC(rdn, exit(1));

                TAILQ_INIT(&rdn->rd_list);

                for (ap = addr; ap - addr < (ssize_t)strlen(addr); ap += c+1) {
                        c = strcspn(ap, ",");
                        strncpy(abuf, ap, c);
                        abuf[c] = '\0';
                        ELM_MALLOC(rdna, goto getconfig_free_rdn);
                        if (inet_pton(AF_INET6, abuf, &rdna->ra_dns) != 1) {
                                syslog(LOG_ERR, "<%s> inet_pton failed for %s",
                                    __func__, abuf);
                                free(rdna);
                                goto getconfig_free_rdn;
                        }
                        TAILQ_INSERT_TAIL(&rdn->rd_list, rdna, ra_next);
                }

                makeentry(entbuf, sizeof(entbuf), i, "rdnssltime");
                MAYHAVE(val, entbuf, (rai->rai_maxinterval * 3 / 2));
                if ((uint16_t)val < rai->rai_maxinterval ||
                    (uint16_t)val > rai->rai_maxinterval * 2) {
                        syslog(LOG_ERR, "%s (%" PRIu16 ") on %s is invalid "
                            "(must be between %d and %d)",
                            entbuf, val, ifi->ifi_ifname, rai->rai_maxinterval,
                            rai->rai_maxinterval * 2);
                        goto getconfig_free_rdn;
                }
                rdn->rd_ltime = val;

                /* link into chain */
                TAILQ_INSERT_TAIL(&rai->rai_rdnss, rdn, rd_next);
                continue;
getconfig_free_rdn:
                while ((rdna = TAILQ_FIRST(&rdn->rd_list)) != NULL) {
                        TAILQ_REMOVE(&rdn->rd_list, rdna, ra_next);
                        free(rdna);
                }
                free(rdn);
        }

        for (i = -1; i < MAXDNSSLENT ; i++) {
                struct dnssl *dns;
                struct dnssl_addr *dnsa;
                char *ap;
                int c;

                makeentry(entbuf, sizeof(entbuf), i, "dnssl");
                addr = (char *)agetstr(entbuf, &bp);
                if (addr == NULL)
                        continue;

                ELM_MALLOC(dns, exit(1));

                TAILQ_INIT(&dns->dn_list);

                for (ap = addr; ap - addr < (ssize_t)strlen(addr); ap += c+1) {
                        c = strcspn(ap, ",");
                        strncpy(abuf, ap, c);
                        abuf[c] = '\0';
                        ELM_MALLOC(dnsa, goto getconfig_free_dns);
                        dnsa->da_len = dname_labelenc(dnsa->da_dom, abuf);
                        if (dnsa->da_len < 0) {
                                syslog(LOG_ERR, "Invalid dnssl entry: %s",
                                    abuf);
                                goto getconfig_free_dns;
                        }
                        syslog(LOG_DEBUG, "<%s>: dnsa->da_len = %d", __func__,
                            dnsa->da_len);
                        TAILQ_INSERT_TAIL(&dns->dn_list, dnsa, da_next);
                }

                makeentry(entbuf, sizeof(entbuf), i, "dnsslltime");
                MAYHAVE(val, entbuf, (rai->rai_maxinterval * 3 / 2));
                if ((uint16_t)val < rai->rai_maxinterval ||
                    (uint16_t)val > rai->rai_maxinterval * 2) {
                        syslog(LOG_ERR, "%s (%" PRIu16 ") on %s is invalid "
                            "(must be between %d and %d)",
                            entbuf, val, ifi->ifi_ifname, rai->rai_maxinterval,
                            rai->rai_maxinterval * 2);
                        goto getconfig_free_dns;
                }
                dns->dn_ltime = val;

                /* link into chain */
                TAILQ_INSERT_TAIL(&rai->rai_dnssl, dns, dn_next);
                continue;
getconfig_free_dns:
                while ((dnsa = TAILQ_FIRST(&dns->dn_list)) != NULL) {
                        TAILQ_REMOVE(&dns->dn_list, dnsa, da_next);
                        free(dnsa);
                }
                free(dns);
        }

        /*
         * handle pref64
         */
        for (i = -1; i < MAXPREF64 ; i++) {
                struct pref64 *prf64;

                makeentry(entbuf, sizeof(entbuf), i, "pref64");
                addr = (char *)agetstr(entbuf, &bp);
                if (addr == NULL)
                        continue;
                ELM_MALLOC(prf64, exit(1));

                if (inet_pton(AF_INET6, addr, &prf64->p64_prefix) != 1) {
                        syslog(LOG_ERR, "<%s> inet_pton failed for %s",
                            __func__, addr);
                        goto getconfig_free_prf64;
                }

                makeentry(entbuf, sizeof(entbuf), i, "pref64len");
                MAYHAVE(val64, entbuf, 96);
                switch (val64) {
                case 96:
                        prf64->p64_plc = 0;
                        break;
                case 64:
                        prf64->p64_plc = 1;
                        break;
                case 56:
                        prf64->p64_plc = 2;
                        break;
                case 48:
                        prf64->p64_plc = 3;
                        break;
                case 40:
                        prf64->p64_plc = 4;
                        break;
                case 32:
                        prf64->p64_plc = 5;
                        break;
                default:
                        syslog(LOG_ERR, "PREF64 prefix length %" PRIi64
                               "on %s is invalid; skipping",
                               val64, ifi->ifi_ifname);
                        goto getconfig_free_prf64;
                }

                makeentry(entbuf, sizeof(entbuf), i, "pref64lifetime");
                MAYHAVE(val64, entbuf, (rai->rai_lifetime * 3));
                /* This logic is from RFC 8781 section 4.1. */
                if (val64 > 65528)
                        val64 = 65528;
                val64 = (val64 + 7) / 8;
                prf64->p64_sl = (uint16_t)val64;

                /* link into chain */
                TAILQ_INSERT_TAIL(&rai->rai_pref64, prf64, p64_next);
                continue;
getconfig_free_prf64:
                free(prf64);
        }

        /* construct the sending packet */
        make_packet(rai);

        /*
         * If an entry with the same ifindex exists, remove it first.
         * Before the removal, RDNSS and DNSSL options with
         * zero-lifetime will be sent.
         */
        switch (ifi->ifi_state) {
        case IFI_STATE_UNCONFIGURED:
                /* UNCONFIGURED -> TRANSITIVE */

                error = sock_mc_join(&sock, ifi->ifi_ifindex);
                if (error)
                        exit(1);

                ifi->ifi_state = IFI_STATE_TRANSITIVE;
                ifi->ifi_burstcount = MAX_INITIAL_RTR_ADVERTISEMENTS;
                ifi->ifi_burstinterval = MAX_INITIAL_RTR_ADVERT_INTERVAL;

                /* The same two rai mean initial burst */
                ifi->ifi_rainfo = rai;
                ifi->ifi_rainfo_trans = rai;
                TAILQ_INSERT_TAIL(&railist, rai, rai_next);

                if (ifi->ifi_ra_timer == NULL)
                        ifi->ifi_ra_timer = rtadvd_add_timer(ra_timeout,
                            ra_timer_update, ifi, ifi);
                ra_timer_update(ifi, &ifi->ifi_ra_timer->rat_tm);
                rtadvd_set_timer(&ifi->ifi_ra_timer->rat_tm,
                    ifi->ifi_ra_timer);

                syslog(LOG_DEBUG,
                    "<%s> ifname=%s marked as TRANSITIVE (initial burst).",
                    __func__, ifi->ifi_ifname);
                break;
        case IFI_STATE_CONFIGURED:
                /* CONFIGURED -> TRANSITIVE */
                rai_old = ifi->ifi_rainfo;
                if (rai_old == NULL) {
                        syslog(LOG_ERR,
                            "<%s> ifi_rainfo is NULL"
                            " in IFI_STATE_CONFIGURED.", __func__);
                        ifi = NULL;
                        break;
                } else {
                        struct rdnss *rdn;
                        struct dnssl *dns;

                        rai_old->rai_lifetime = 0;
                        TAILQ_FOREACH(rdn, &rai_old->rai_rdnss, rd_next)
                            rdn->rd_ltime = 0;
                        TAILQ_FOREACH(dns, &rai_old->rai_dnssl, dn_next)
                            dns->dn_ltime = 0;

                        ifi->ifi_rainfo_trans = rai_old;
                        ifi->ifi_state = IFI_STATE_TRANSITIVE;
                        ifi->ifi_burstcount = MAX_FINAL_RTR_ADVERTISEMENTS;
                        ifi->ifi_burstinterval = MIN_DELAY_BETWEEN_RAS;

                        ra_timer_update(ifi, &ifi->ifi_ra_timer->rat_tm);
                        rtadvd_set_timer(&ifi->ifi_ra_timer->rat_tm,
                            ifi->ifi_ra_timer);

                        syslog(LOG_DEBUG,
                            "<%s> ifname=%s marked as TRANSITIVE"
                            " (transitional burst)",
                            __func__, ifi->ifi_ifname);
                }
                ifi->ifi_rainfo = rai;
                TAILQ_INSERT_TAIL(&railist, rai, rai_next);
                break;
        case IFI_STATE_TRANSITIVE:
                if (ifi->ifi_rainfo != NULL) {
                        if (ifi->ifi_rainfo == ifi->ifi_rainfo_trans) {
                                /* Reinitialize initial burst */
                                rm_rainfo(ifi->ifi_rainfo);
                                ifi->ifi_rainfo = rai;
                                ifi->ifi_rainfo_trans = rai;
                                ifi->ifi_burstcount =
                                    MAX_INITIAL_RTR_ADVERTISEMENTS;
                                ifi->ifi_burstinterval =
                                    MAX_INITIAL_RTR_ADVERT_INTERVAL;
                        } else {
                                /* Replace ifi_rainfo with the new one */
                                rm_rainfo(ifi->ifi_rainfo);
                                ifi->ifi_rainfo = rai;
                        }
                        TAILQ_INSERT_TAIL(&railist, rai, rai_next);

                        ra_timer_update(ifi, &ifi->ifi_ra_timer->rat_tm);
                        rtadvd_set_timer(&ifi->ifi_ra_timer->rat_tm,
                            ifi->ifi_ra_timer);
                } else {
                        /* XXX: NOTREACHED.  Being shut down. */
                        syslog(LOG_ERR,
                            "<%s> %s is shutting down.  Skipped.",
                            __func__, ifi->ifi_ifname);
                        rm_rainfo(rai);

                        return (NULL);
                }
                break;
        }

        return (ifi);

getconfig_free_rai:
        free(rai);
        return (NULL);
}

void
get_prefix(struct rainfo *rai)
{
        struct ifaddrs *ifap, *ifa;
        struct prefix *pfx;
        struct in6_addr *a;
        struct ifinfo *ifi;
        char *p, *ep, *m, *lim;
        char ntopbuf[INET6_ADDRSTRLEN];

        if (getifaddrs(&ifap) < 0) {
                syslog(LOG_ERR,
                    "<%s> can't get interface addresses",
                    __func__);
                exit(1);
        }
        ifi = rai->rai_ifinfo;

        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                int plen;

                if (strcmp(ifa->ifa_name, ifi->ifi_ifname) != 0)
                        continue;
                if (ifa->ifa_addr->sa_family != AF_INET6)
                        continue;
                a = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
                if (IN6_IS_ADDR_LINKLOCAL(a))
                        continue;

                /* get prefix length */
                m = (char *)&((struct sockaddr_in6 *)ifa->ifa_netmask)->sin6_addr;
                lim = (char *)(ifa->ifa_netmask) + ifa->ifa_netmask->sa_len;
                plen = prefixlen(m, lim);
                if (plen <= 0 || plen > 128) {
                        syslog(LOG_ERR, "<%s> failed to get prefixlen "
                            "or prefix is invalid",
                            __func__);
                        exit(1);
                }
                if (plen == 128)        /* XXX */
                        continue;
                if (find_prefix(rai, a, plen)) {
                        /* ignore a duplicated prefix. */
                        continue;
                }

                /* allocate memory to store prefix info. */
                ELM_MALLOC(pfx, exit(1));

                /* set prefix, sweep bits outside of prefixlen */
                pfx->pfx_prefixlen = plen;
                memcpy(&pfx->pfx_prefix, a, sizeof(*a));
                p = (char *)&pfx->pfx_prefix;
                ep = (char *)(&pfx->pfx_prefix + 1);
                while (m < lim && p < ep)
                        *p++ &= *m++;
                while (p < ep)
                        *p++ = 0x00;
                if (!inet_ntop(AF_INET6, &pfx->pfx_prefix, ntopbuf,
                    sizeof(ntopbuf))) {
                        syslog(LOG_ERR, "<%s> inet_ntop failed", __func__);
                        exit(1);
                }
                syslog(LOG_DEBUG,
                    "<%s> add %s/%d to prefix list on %s",
                    __func__, ntopbuf, pfx->pfx_prefixlen, ifi->ifi_ifname);

                /* set other fields with protocol defaults */
                pfx->pfx_validlifetime = DEF_ADVVALIDLIFETIME;
                pfx->pfx_preflifetime = DEF_ADVPREFERREDLIFETIME;
                pfx->pfx_onlinkflg = 1;
                pfx->pfx_autoconfflg = 1;
                pfx->pfx_origin = PREFIX_FROM_KERNEL;
                pfx->pfx_rainfo = rai;

                /* link into chain */
                TAILQ_INSERT_TAIL(&rai->rai_prefix, pfx, pfx_next);

                /* counter increment */
                rai->rai_pfxs++;
        }

        freeifaddrs(ifap);
}

static void
makeentry(char *buf, size_t len, int id, const char *string)
{

        if (id < 0)
                strlcpy(buf, string, len);
        else
                snprintf(buf, len, "%s%d", string, id);
}

/*
 * Add a prefix to the list of specified interface and reconstruct
 * the outgoing packet.
 * The prefix must not be in the list.
 * XXX: other parameters of the prefix (e.g. lifetime) should be
 * able to be specified.
 */
static void
add_prefix(struct rainfo *rai, struct in6_prefixreq *ipr)
{
        struct prefix *pfx;
        struct ifinfo *ifi;
        char ntopbuf[INET6_ADDRSTRLEN];

        ifi = rai->rai_ifinfo;
        ELM_MALLOC(pfx, return);
        pfx->pfx_prefix = ipr->ipr_prefix.sin6_addr;
        pfx->pfx_prefixlen = ipr->ipr_plen;
        pfx->pfx_validlifetime = ipr->ipr_vltime;
        pfx->pfx_preflifetime = ipr->ipr_pltime;
        pfx->pfx_onlinkflg = ipr->ipr_raf_onlink;
        pfx->pfx_autoconfflg = ipr->ipr_raf_auto;
        pfx->pfx_origin = PREFIX_FROM_DYNAMIC;
        pfx->pfx_rainfo = rai;

        TAILQ_INSERT_TAIL(&rai->rai_prefix, pfx, pfx_next);

        syslog(LOG_DEBUG, "<%s> new prefix %s/%d was added on %s",
            __func__,
            inet_ntop(AF_INET6, &ipr->ipr_prefix.sin6_addr, ntopbuf,
                sizeof(ntopbuf)), ipr->ipr_plen, ifi->ifi_ifname);

        rai->rai_pfxs++;
}

/*
 * Delete a prefix to the list of specified interface and reconstruct
 * the outgoing packet.
 * The prefix must be in the list.
 */
void
delete_prefix(struct prefix *pfx)
{
        struct rainfo *rai;
        struct ifinfo *ifi;
        char ntopbuf[INET6_ADDRSTRLEN];

        rai = pfx->pfx_rainfo;
        ifi = rai->rai_ifinfo;
        TAILQ_REMOVE(&rai->rai_prefix, pfx, pfx_next);
        syslog(LOG_DEBUG, "<%s> prefix %s/%d was deleted on %s",
            __func__,
            inet_ntop(AF_INET6, &pfx->pfx_prefix, ntopbuf,
                sizeof(ntopbuf)), pfx->pfx_prefixlen, ifi->ifi_ifname);
        if (pfx->pfx_timer)
                rtadvd_remove_timer(pfx->pfx_timer);
        free(pfx);

        rai->rai_pfxs--;
}

void
invalidate_prefix(struct prefix *pfx)
{
        struct timespec timo;
        struct rainfo *rai;
        struct ifinfo *ifi;
        char ntopbuf[INET6_ADDRSTRLEN];

        rai = pfx->pfx_rainfo;
        ifi = rai->rai_ifinfo;
        if (pfx->pfx_timer) {   /* sanity check */
                syslog(LOG_ERR,
                    "<%s> assumption failure: timer already exists",
                    __func__);
                exit(1);
        }

        syslog(LOG_DEBUG, "<%s> prefix %s/%d was invalidated on %s, "
            "will expire in %ld seconds", __func__,
            inet_ntop(AF_INET6, &pfx->pfx_prefix, ntopbuf, sizeof(ntopbuf)),
            pfx->pfx_prefixlen, ifi->ifi_ifname, (long)prefix_timo);

        /* set the expiration timer */
        pfx->pfx_timer = rtadvd_add_timer(prefix_timeout, NULL, pfx, NULL);
        if (pfx->pfx_timer == NULL) {
                syslog(LOG_ERR, "<%s> failed to add a timer for a prefix. "
                    "remove the prefix", __func__);
                delete_prefix(pfx);
        }
        timo.tv_sec = prefix_timo;
        timo.tv_nsec = 0;
        rtadvd_set_timer(&timo, pfx->pfx_timer);
}

static struct rtadvd_timer *
prefix_timeout(void *arg)
{

        delete_prefix((struct prefix *)arg);

        return (NULL);
}

void
update_prefix(struct prefix *pfx)
{
        struct rainfo *rai;
        struct ifinfo *ifi;
        char ntopbuf[INET6_ADDRSTRLEN];

        rai = pfx->pfx_rainfo;
        ifi = rai->rai_ifinfo;
        if (pfx->pfx_timer == NULL) { /* sanity check */
                syslog(LOG_ERR,
                    "<%s> assumption failure: timer does not exist",
                    __func__);
                exit(1);
        }

        syslog(LOG_DEBUG, "<%s> prefix %s/%d was re-enabled on %s",
            __func__, inet_ntop(AF_INET6, &pfx->pfx_prefix, ntopbuf,
                sizeof(ntopbuf)), pfx->pfx_prefixlen, ifi->ifi_ifname);

        /* stop the expiration timer */
        rtadvd_remove_timer(pfx->pfx_timer);
        pfx->pfx_timer = NULL;
}

/*
 * Try to get an in6_prefixreq contents for a prefix which matches
 * ipr->ipr_prefix and ipr->ipr_plen and belongs to
 * the interface whose name is ipr->ipr_name[].
 */
static int
init_prefix(struct in6_prefixreq *ipr)
{
#if 0
        int s;

        if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
                syslog(LOG_ERR, "<%s> socket: %s", __func__,
                    strerror(errno));
                exit(1);
        }

        if (ioctl(s, SIOCGIFPREFIX_IN6, (caddr_t)ipr) < 0) {
                syslog(LOG_INFO, "<%s> ioctl:SIOCGIFPREFIX %s", __func__,
                    strerror(errno));

                ipr->ipr_vltime = DEF_ADVVALIDLIFETIME;
                ipr->ipr_pltime = DEF_ADVPREFERREDLIFETIME;
                ipr->ipr_raf_onlink = 1;
                ipr->ipr_raf_auto = 1;
                /* omit other field initialization */
        }
        else if (ipr->ipr_origin < PR_ORIG_RR) {
                char ntopbuf[INET6_ADDRSTRLEN];

                syslog(LOG_WARNING, "<%s> Added prefix(%s)'s origin %d is"
                    "lower than PR_ORIG_RR(router renumbering)."
                    "This should not happen if I am router", __func__,
                    inet_ntop(AF_INET6, &ipr->ipr_prefix.sin6_addr, ntopbuf,
                        sizeof(ntopbuf)), ipr->ipr_origin);
                close(s);
                return (1);
        }

        close(s);
        return (0);
#else
        ipr->ipr_vltime = DEF_ADVVALIDLIFETIME;
        ipr->ipr_pltime = DEF_ADVPREFERREDLIFETIME;
        ipr->ipr_raf_onlink = 1;
        ipr->ipr_raf_auto = 1;
        return (0);
#endif
}

void
make_prefix(struct rainfo *rai, int ifindex, struct in6_addr *addr, int plen)
{
        struct in6_prefixreq ipr;

        memset(&ipr, 0, sizeof(ipr));
        if (if_indextoname(ifindex, ipr.ipr_name) == NULL) {
                syslog(LOG_ERR, "<%s> Prefix added interface No.%d doesn't "
                    "exist. This should not happen! %s", __func__,
                    ifindex, strerror(errno));
                exit(1);
        }
        ipr.ipr_prefix.sin6_len = sizeof(ipr.ipr_prefix);
        ipr.ipr_prefix.sin6_family = AF_INET6;
        ipr.ipr_prefix.sin6_addr = *addr;
        ipr.ipr_plen = plen;

        if (init_prefix(&ipr))
                return; /* init failed by some error */
        add_prefix(rai, &ipr);
}

void
make_packet(struct rainfo *rai)
{
        size_t packlen, lladdroptlen = 0;
        char *buf;
        struct nd_router_advert *ra;
        struct nd_opt_prefix_info *ndopt_pi;
        struct nd_opt_mtu *ndopt_mtu;
        struct nd_opt_route_info *ndopt_rti;
        struct rtinfo *rti;
        struct nd_opt_rdnss *ndopt_rdnss;
        struct rdnss *rdn;
        struct nd_opt_dnssl *ndopt_dnssl;
        struct dnssl *dns;
        struct pref64 *prf64;
        struct nd_opt_pref64 *ndopt_pref64;
        size_t len;
        struct prefix *pfx;
        struct ifinfo *ifi;

        ifi = rai->rai_ifinfo;
        /* calculate total length */
        packlen = sizeof(struct nd_router_advert);
        if (rai->rai_advlinkopt) {
                if ((lladdroptlen = lladdropt_length(&ifi->ifi_sdl)) == 0) {
                        syslog(LOG_INFO,
                            "<%s> link-layer address option has"
                            " null length on %s.  Treat as not included.",
                            __func__, ifi->ifi_ifname);
                        rai->rai_advlinkopt = 0;
                }
                packlen += lladdroptlen;
        }
        if (rai->rai_pfxs)
                packlen += sizeof(struct nd_opt_prefix_info) * rai->rai_pfxs;
        if (rai->rai_linkmtu)
                packlen += sizeof(struct nd_opt_mtu);

        TAILQ_FOREACH(rti, &rai->rai_route, rti_next)
                packlen += sizeof(struct nd_opt_route_info) +
                           ((rti->rti_prefixlen + 0x3f) >> 6) * 8;

        TAILQ_FOREACH(rdn, &rai->rai_rdnss, rd_next) {
                struct rdnss_addr *rdna;

                packlen += sizeof(struct nd_opt_rdnss);
                TAILQ_FOREACH(rdna, &rdn->rd_list, ra_next)
                        packlen += sizeof(rdna->ra_dns);
        }
        TAILQ_FOREACH(dns, &rai->rai_dnssl, dn_next) {
                struct dnssl_addr *dnsa;

                packlen += sizeof(struct nd_opt_dnssl);
                len = 0;
                TAILQ_FOREACH(dnsa, &dns->dn_list, da_next)
                        len += dnsa->da_len;

                /* A zero octet and 8 octet boundary */
                len++;
                len += (len % 8) ? 8 - len % 8 : 0;

                packlen += len;
        }
        TAILQ_FOREACH(prf64, &rai->rai_pref64, p64_next)
                packlen += sizeof(struct nd_opt_pref64);

        /* allocate memory for the packet */
        if ((buf = malloc(packlen)) == NULL) {
                syslog(LOG_ERR,
                    "<%s> can't get enough memory for an RA packet",
                    __func__);
                exit(1);
        }
        memset(buf, 0, packlen);
        if (rai->rai_ra_data)   /* Free old data if any. */
                free(rai->rai_ra_data);
        rai->rai_ra_data = buf;
        /* XXX: what if packlen > 576? */
        rai->rai_ra_datalen = packlen;

        /*
         * construct the packet
         */
        ra = (struct nd_router_advert *)buf;
        ra->nd_ra_type = ND_ROUTER_ADVERT;
        ra->nd_ra_code = 0;
        ra->nd_ra_cksum = 0;
        ra->nd_ra_curhoplimit = (uint8_t)(0xff & rai->rai_hoplimit);
        /*
         * XXX: the router preference field, which is a 2-bit field, should be
         * initialized before other fields.
         */
        ra->nd_ra_flags_reserved = 0xff & rai->rai_rtpref;
        ra->nd_ra_flags_reserved |=
                rai->rai_managedflg ? ND_RA_FLAG_MANAGED : 0;
        ra->nd_ra_flags_reserved |=
                rai->rai_otherflg ? ND_RA_FLAG_OTHER : 0;
#ifdef DRAFT_IETF_6MAN_IPV6ONLY_FLAG
        ra->nd_ra_flags_reserved |=
                rai->rai_ipv6onlyflg ? ND_RA_FLAG_IPV6_ONLY : 0;
#endif
        ra->nd_ra_router_lifetime = htons(rai->rai_lifetime);
        ra->nd_ra_reachable = htonl(rai->rai_reachabletime);
        ra->nd_ra_retransmit = htonl(rai->rai_retranstimer);
        buf += sizeof(*ra);

        if (rai->rai_advlinkopt) {
                lladdropt_fill(&ifi->ifi_sdl, (struct nd_opt_hdr *)buf);
                buf += lladdroptlen;
        }

        if (rai->rai_linkmtu) {
                ndopt_mtu = (struct nd_opt_mtu *)buf;
                ndopt_mtu->nd_opt_mtu_type = ND_OPT_MTU;
                ndopt_mtu->nd_opt_mtu_len = 1;
                ndopt_mtu->nd_opt_mtu_reserved = 0;
                ndopt_mtu->nd_opt_mtu_mtu = htonl(rai->rai_linkmtu);
                buf += sizeof(struct nd_opt_mtu);
        }

        TAILQ_FOREACH(pfx, &rai->rai_prefix, pfx_next) {
                uint32_t vltime, pltime;
                struct timespec now;

                ndopt_pi = (struct nd_opt_prefix_info *)buf;
                ndopt_pi->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
                ndopt_pi->nd_opt_pi_len = 4;
                ndopt_pi->nd_opt_pi_prefix_len = pfx->pfx_prefixlen;
                ndopt_pi->nd_opt_pi_flags_reserved = 0;
                if (pfx->pfx_onlinkflg)
                        ndopt_pi->nd_opt_pi_flags_reserved |=
                                ND_OPT_PI_FLAG_ONLINK;
                if (pfx->pfx_autoconfflg)
                        ndopt_pi->nd_opt_pi_flags_reserved |=
                                ND_OPT_PI_FLAG_AUTO;
                if (pfx->pfx_timer)
                        vltime = 0;
                else {
                        if (pfx->pfx_vltimeexpire || pfx->pfx_pltimeexpire)
                                clock_gettime(CLOCK_MONOTONIC_FAST, &now);
                        if (pfx->pfx_vltimeexpire == 0)
                                vltime = pfx->pfx_validlifetime;
                        else
                                vltime = ((time_t)pfx->pfx_vltimeexpire > now.tv_sec) ?
                                    pfx->pfx_vltimeexpire - now.tv_sec : 0;
                }
                if (pfx->pfx_timer)
                        pltime = 0;
                else {
                        if (pfx->pfx_pltimeexpire == 0)
                                pltime = pfx->pfx_preflifetime;
                        else
                                pltime = ((time_t)pfx->pfx_pltimeexpire > now.tv_sec) ?
                                    pfx->pfx_pltimeexpire - now.tv_sec : 0;
                }
                if (vltime < pltime) {
                        /*
                         * this can happen if vltime is decrement but pltime
                         * is not.
                         */
                        pltime = vltime;
                }
                ndopt_pi->nd_opt_pi_valid_time = htonl(vltime);
                ndopt_pi->nd_opt_pi_preferred_time = htonl(pltime);
                ndopt_pi->nd_opt_pi_reserved2 = 0;
                ndopt_pi->nd_opt_pi_prefix = pfx->pfx_prefix;

                buf += sizeof(struct nd_opt_prefix_info);
        }

        TAILQ_FOREACH(rti, &rai->rai_route, rti_next) {
                uint8_t psize = (rti->rti_prefixlen + 0x3f) >> 6;

                ndopt_rti = (struct nd_opt_route_info *)buf;
                ndopt_rti->nd_opt_rti_type = ND_OPT_ROUTE_INFO;
                ndopt_rti->nd_opt_rti_len = 1 + psize;
                ndopt_rti->nd_opt_rti_prefixlen = rti->rti_prefixlen;
                ndopt_rti->nd_opt_rti_flags = 0xff & rti->rti_rtpref;
                ndopt_rti->nd_opt_rti_lifetime = htonl(rti->rti_ltime);
                memcpy(ndopt_rti + 1, &rti->rti_prefix, psize * 8);
                buf += sizeof(struct nd_opt_route_info) + psize * 8;
        }

        TAILQ_FOREACH(rdn, &rai->rai_rdnss, rd_next) {
                struct rdnss_addr *rdna;

                ndopt_rdnss = (struct nd_opt_rdnss *)buf;
                ndopt_rdnss->nd_opt_rdnss_type = ND_OPT_RDNSS;
                ndopt_rdnss->nd_opt_rdnss_len = 0;
                ndopt_rdnss->nd_opt_rdnss_reserved = 0;
                ndopt_rdnss->nd_opt_rdnss_lifetime = htonl(rdn->rd_ltime);
                buf += sizeof(struct nd_opt_rdnss);

                TAILQ_FOREACH(rdna, &rdn->rd_list, ra_next) {
                        memcpy(buf, &rdna->ra_dns, sizeof(rdna->ra_dns));
                        buf += sizeof(rdna->ra_dns);
                }
                /* Length field should be in 8 octets */
                ndopt_rdnss->nd_opt_rdnss_len = (buf - (char *)ndopt_rdnss) / 8;

                syslog(LOG_DEBUG, "<%s>: nd_opt_dnss_len = %d", __func__,
                    ndopt_rdnss->nd_opt_rdnss_len);
        }

        TAILQ_FOREACH(dns, &rai->rai_dnssl, dn_next) {
                struct dnssl_addr *dnsa;

                ndopt_dnssl = (struct nd_opt_dnssl *)buf;
                ndopt_dnssl->nd_opt_dnssl_type = ND_OPT_DNSSL;
                ndopt_dnssl->nd_opt_dnssl_len = 0;
                ndopt_dnssl->nd_opt_dnssl_reserved = 0;
                ndopt_dnssl->nd_opt_dnssl_lifetime = htonl(dns->dn_ltime);
                buf += sizeof(*ndopt_dnssl);

                TAILQ_FOREACH(dnsa, &dns->dn_list, da_next) {
                        memcpy(buf, dnsa->da_dom, dnsa->da_len);
                        buf += dnsa->da_len;
                }

                /* A zero octet after encoded DNS server list. */
                *buf++ = '\0';

                /* Padding to next 8 octets boundary */
                len = buf - (char *)ndopt_dnssl;
                len += (len % 8) ? 8 - len % 8 : 0;
                buf = (char *)ndopt_dnssl + len;

                /* Length field must be in 8 octets */
                ndopt_dnssl->nd_opt_dnssl_len = len / 8;

                syslog(LOG_DEBUG, "<%s>: nd_opt_dnssl_len = %d", __func__,
                    ndopt_dnssl->nd_opt_dnssl_len);
        }

        TAILQ_FOREACH(prf64, &rai->rai_pref64, p64_next) {
                ndopt_pref64 = (struct nd_opt_pref64 *)buf;
                ndopt_pref64->nd_opt_pref64_type = ND_OPT_PREF64;
                ndopt_pref64->nd_opt_pref64_len = 2;
                ndopt_pref64->nd_opt_pref64_sl_plc =
                        (htons(prf64->p64_sl << 3)) |
                        htons((prf64->p64_plc & 0x7));
                memcpy(&ndopt_pref64->nd_opt_prefix[0],
                       &prf64->p64_prefix,
                       sizeof(ndopt_pref64->nd_opt_prefix));
                buf += sizeof(struct nd_opt_pref64);
        }
}