[apple/network_cmds.git] / rtadvd.tproj / config.c

/*
 * Copyright (c) 2009-2012 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

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

/*
 * Copyright (C) 1998 WIDE Project.
 * 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 <sys/time.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_var.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 <string.h>
#include <search.h>
#include <stdlib.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <stddef.h>

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

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

static struct rtadvd_timer *prefix_timeout(void *);
static void makeentry(char *, size_t, int, char *);
static int getinet6sysctl(int);
static int encode_domain(char *, u_char *);

void
getconfig(intface)
        char *intface;
{
        int stat, i;
        int rdnss_length;
        int dnssl_length;
        char tbuf[BUFSIZ];
        struct rainfo *tmp;
        long val;
        int64_t val64;
        char buf[BUFSIZ];
        char *bp = buf;
        char *addr, *flagstr;
        static int forwarding = -1;

#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)

        if ((stat = agetent(tbuf, intface)) <= 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__, intface);
        }

        tmp = (struct rainfo *)malloc(sizeof(*ralist));
        if (tmp == NULL) {
                syslog(LOG_INFO, "<%s> %s: can't allocate enough memory",
                    __func__, intface);
                exit(1);
        }
        memset(tmp, 0, sizeof(*tmp));
        tmp->prefix.next = tmp->prefix.prev = &tmp->prefix;
#ifdef ROUTEINFO
        tmp->route.next = tmp->route.prev = &tmp->route;
#endif
        tmp->rdnss_list.next = tmp->rdnss_list.prev = &tmp->rdnss_list;
        tmp->dnssl_list.next = tmp->dnssl_list.prev = &tmp->dnssl_list;

        /* check if we are allowed to forward packets (if not determined) */
        if (forwarding < 0) {
                if ((forwarding = getinet6sysctl(IPV6CTL_FORWARDING)) < 0)
                        exit(1);
        }

        /* get interface information */
        if (agetflag("nolladdr"))
                tmp->advlinkopt = 0;
        else
                tmp->advlinkopt = 1;
        if (tmp->advlinkopt) {
                if ((tmp->sdl = if_nametosdl(intface)) == NULL) {
                        syslog(LOG_ERR,
                               "<%s> can't get information of %s",
                               __func__, intface);
                        exit(1);
                }
                tmp->ifindex = tmp->sdl->sdl_index;
        } else
                tmp->ifindex = if_nametoindex(intface);
        strncpy(tmp->ifname, intface, sizeof(tmp->ifname));
        if ((tmp->phymtu = if_getmtu(intface)) == 0) {
                tmp->phymtu = IPV6_MMTU;
                syslog(LOG_WARNING,
                       "<%s> can't get interface mtu of %s. Treat as %d",
                       __func__, intface, IPV6_MMTU);
        }

        /*
         * set router configuration variables.
         */
        MAYHAVE(val, "maxinterval", DEF_MAXRTRADVINTERVAL);
        if (val < MIN_MAXINTERVAL || val > MAX_MAXINTERVAL) {
                syslog(LOG_ERR,
                       "<%s> maxinterval (%ld) on %s is invalid "
                       "(must be between %u and %u)", __func__, val,
                       intface, MIN_MAXINTERVAL, MAX_MAXINTERVAL);
                exit(1);
        }
        tmp->maxinterval = (u_int)val;
        MAYHAVE(val, "mininterval", tmp->maxinterval/3);
        if (val < MIN_MININTERVAL || val > (tmp->maxinterval * 3) / 4) {
                syslog(LOG_ERR,
                       "<%s> mininterval (%ld) on %s is invalid "
                       "(must be between %d and %d)",
                       __func__, val, intface, MIN_MININTERVAL,
                       (tmp->maxinterval * 3) / 4);
                exit(1);
        }
        tmp->mininterval = (u_int)val;

        MAYHAVE(val, "chlim", DEF_ADVCURHOPLIMIT);
        tmp->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__);
                                exit(1);
                        }
                        val |= ND_RA_FLAG_RTPREF_LOW;
                }
        } else {
                MAYHAVE(val, "raflags", 0);
        }
        tmp->managedflg = val & ND_RA_FLAG_MANAGED;
        tmp->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
        tmp->rtpref = val & ND_RA_FLAG_RTPREF_MASK;
        if (tmp->rtpref == ND_RA_FLAG_RTPREF_RSV) {
                syslog(LOG_ERR, "<%s> invalid router preference (%02x) on %s",
                       __func__, tmp->rtpref, intface);
                exit(1);
        }

        MAYHAVE(val, "rltime", tmp->maxinterval * 3);
        if (val && (val < tmp->maxinterval || val > MAXROUTERLIFETIME)) {
                syslog(LOG_ERR,
                       "<%s> router lifetime (%ld) on %s is invalid "
                       "(must be 0 or between %d and %d)",
                       __func__, val, intface,
                       tmp->maxinterval,
                       MAXROUTERLIFETIME);
                exit(1);
        }
        /*
         * Basically, hosts MUST NOT send Router Advertisement messages at any
         * time (RFC 2461, Section 6.2.3). However, it would sometimes be
         * useful to allow hosts to advertise some parameters such as prefix
         * information and link MTU. Thus, we allow hosts to invoke rtadvd
         * only when router lifetime (on every advertising interface) is
         * explicitly set zero. (see also the above section)
         */
        if (val && forwarding == 0) {
                syslog(LOG_ERR,
                       "<%s> non zero router lifetime is specified for %s, "
                       "which must not be allowed for hosts.  you must "
                       "change router lifetime or enable IPv6 forwarding.",
                       __func__, intface);
                exit(1);
        }
        tmp->lifetime = val & 0xffff;

        MAYHAVE(val, "rtime", DEF_ADVREACHABLETIME);
        if (val < 0 || val > MAXREACHABLETIME) {
                syslog(LOG_ERR,
                       "<%s> reachable time (%ld) on %s is invalid "
                       "(must be no greater than %d)",
                       __func__, val, intface, MAXREACHABLETIME);
                exit(1);
        }
        tmp->reachabletime = (u_int32_t)val;

        MAYHAVE(val64, "retrans", DEF_ADVRETRANSTIMER);
        if (val64 < 0 || val64 > 0xffffffff) {
                syslog(LOG_ERR, "<%s> retrans time (%lld) on %s out of range",
                       __func__, (long long)val64, intface);
                exit(1);
        }
        tmp->retranstimer = (u_int32_t)val64;

        if (agetnum("hapref") != -1 || agetnum("hatime") != -1) {
                syslog(LOG_ERR,
                       "<%s> mobile-ip6 configuration not supported",
                       __func__);
                exit(1);
        }
        /* 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);
        tmp->clockskew = val;

        tmp->pfxs = 0;
        for (i = -1; i < MAXPREFIX; i++) {
                struct prefix *pfx;
                char entbuf[256];

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

                /* allocate memory to store prefix information */
                if ((pfx = malloc(sizeof(struct prefix))) == NULL) {
                        syslog(LOG_ERR,
                               "<%s> can't allocate enough memory",
                               __func__);
                        exit(1);
                }
                memset(pfx, 0, sizeof(*pfx));

                /* link into chain */
                insque(pfx, &tmp->prefix);
                tmp->pfxs++;
                pfx->rainfo = tmp;

                pfx->origin = PREFIX_FROM_CONFIG;

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

                makeentry(entbuf, sizeof(entbuf), i, "prefixlen");
                MAYHAVE(val, entbuf, 64);
                if (val < 0 || val > 128) {
                        syslog(LOG_ERR, "<%s> prefixlen (%ld) for %s "
                               "on %s out of range",
                               __func__, val, addr, intface);
                        exit(1);
                }
                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->onlinkflg = val & ND_OPT_PI_FLAG_ONLINK;
                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 (%lld) for "
                            "%s/%d on %s is out of range",
                            __func__, (long long)val64,
                            addr, pfx->prefixlen, intface);
                        exit(1);
                }
                pfx->validlifetime = (u_int32_t)val64;

                makeentry(entbuf, sizeof(entbuf), i, "vltimedecr");
                if (agetflag(entbuf)) {
                        struct timeval now;
                        gettimeofday(&now, 0);
                        pfx->vltimeexpire =
                                now.tv_sec + pfx->validlifetime;
                }

                makeentry(entbuf, sizeof(entbuf), i, "pltime");
                MAYHAVE(val64, entbuf, DEF_ADVPREFERREDLIFETIME);
                if (val64 < 0 || val64 > 0xffffffff) {
                        syslog(LOG_ERR,
                            "<%s> pltime (%lld) for %s/%d on %s "
                            "is out of range",
                            __func__, (long long)val64,
                            addr, pfx->prefixlen, intface);
                        exit(1);
                }
                pfx->preflifetime = (u_int32_t)val64;

                makeentry(entbuf, sizeof(entbuf), i, "pltimedecr");
                if (agetflag(entbuf)) {
                        struct timeval now;
                        gettimeofday(&now, 0);
                        pfx->pltimeexpire =
                                now.tv_sec + pfx->preflifetime;
                }
        }
        if (tmp->pfxs == 0)
                get_prefix(tmp);

        MAYHAVE(val, "mtu", 0);
        if (val < 0 || val > 0xffffffff) {
                syslog(LOG_ERR,
                       "<%s> mtu (%ld) on %s out of range",
                       __func__, val, intface);
                exit(1);
        }
        tmp->linkmtu = (u_int32_t)val;
        if (tmp->linkmtu == 0) {
                char *mtustr;

                if ((mtustr = (char *)agetstr("mtu", &bp)) &&
                    strcmp(mtustr, "auto") == 0)
                        tmp->linkmtu = tmp->phymtu;
        }
        else if (tmp->linkmtu < IPV6_MMTU || tmp->linkmtu > tmp->phymtu) {
                syslog(LOG_ERR,
                       "<%s> advertised link mtu (%lu) on %s is invalid (must "
                       "be between least MTU (%d) and physical link MTU (%d)",
                       __func__, (unsigned long)tmp->linkmtu, intface,
                       IPV6_MMTU, tmp->phymtu);
                exit(1);
        }

#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));
                strncpy(ndi.ifname, intface, IFNAMSIZ);
                if (ioctl(s, SIOCGIFINFO_IN6, (caddr_t)&ndi) < 0) {
                        syslog(LOG_INFO, "<%s> ioctl:SIOCGIFINFO_IN6 at %s: %s",
                             __func__, intface, strerror(errno));
                }

                /* reflect the RA info to the host variables in kernel */
                ndi.ndi.chlim = tmp->hoplimit;
                ndi.ndi.retrans = tmp->retranstimer;
                ndi.ndi.basereachable = tmp->reachabletime;
                if (ioctl(s, SIOCSIFINFO_IN6, (caddr_t)&ndi) < 0) {
                        syslog(LOG_INFO, "<%s> ioctl:SIOCSIFINFO_IN6 at %s: %s",
                             __func__, intface, strerror(errno));
                }
                close(s);
        }
#endif

        /* route information */
#ifdef ROUTEINFO
        tmp->routes = 0;
        for (i = -1; i < MAXROUTE; i++) {
                struct rtinfo *rti;
                char entbuf[256], oentbuf[256];

                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 */
                if ((rti = malloc(sizeof(struct rtinfo))) == NULL) {
                        syslog(LOG_ERR,
                               "<%s> can't allocate enough memory",
                               __func__);
                        exit(1);
                }
                memset(rti, 0, sizeof(*rti));

                /* link into chain */
                insque(rti, &tmp->route);
                tmp->routes++;

                if (inet_pton(AF_INET6, addr, &rti->prefix) != 1) {
                        syslog(LOG_ERR, "<%s> inet_pton failed for %s",
                               __func__, addr);
                        exit(1);
                }
#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, intface);
                        exit(1);
                }
                if (IN6_IS_ADDR_LINKLOCAL(&rti->prefix)) {
                        syslog(LOG_NOTICE,
                               "<%s> link-local route (%s) will "
                               "be advertised on %s",
                               __func__, addr, intface);
                        exit(1);
                }
#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 (%ld) for %s on %s "
                               "out of range",
                               __func__, val, addr, intface);
                        exit(1);
                }
                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__);
                                        exit(1);
                                }
                                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->rtpref = val & ND_RA_FLAG_RTPREF_MASK;
                if (rti->rtpref == ND_RA_FLAG_RTPREF_RSV) {
                        syslog(LOG_ERR, "<%s> invalid route preference (%02x) "
                               "for %s/%d on %s",
                               __func__, rti->rtpref, addr,
                               rti->prefixlen, intface);
                        exit(1);
                }

                /*
                 * 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, intface);
                                val64 = tmp->lifetime;
                        }
                }
                if (val64 < 0 || val64 > 0xffffffff) {
                        syslog(LOG_ERR, "<%s> route lifetime (%lld) for "
                            "%s/%d on %s out of range", __func__,
                            (long long)val64, addr, rti->prefixlen, intface);
                        exit(1);
                }
                rti->ltime = (u_int32_t)val64;
        }
#endif

        /* RDNSS option (RFC5006) */
        MAYHAVE(val, "rdnsslifetime", 2 * tmp->maxinterval);
        if (val < tmp->maxinterval || val > (2 * tmp->maxinterval)) {
            syslog(LOG_NOTICE,
                   "<%s> rdnsslifetime (%lu) on %s SHOULD "
                   "be between %u and %u", __func__, val,
                   intface, tmp->maxinterval, 2 * tmp->maxinterval);
        }
        tmp->rdnss_lifetime = val;
        if ((rdnss_length = agetnum("rdnssaddrs")) < 0) {
            tmp->rdnss_length = 0;
        }
        else {
            tmp->rdnss_length = rdnss_length;

            /* traverse in reverse order so that the queue has correct order */
            for (i = (rdnss_length - 1); i >= 0; i--) {
                struct rdnss *rdnss;
                char entbuf[256];

                /* allocate memory to store server address information */
                if ((rdnss = malloc(sizeof(struct rdnss))) == NULL) {
                        syslog(LOG_ERR,
                               "<%s> can't allocate enough memory",
                               __func__);
                        exit(1);
                }
                memset(rdnss, 0, sizeof(*rdnss));

                /* link into chain */
                insque(rdnss, &tmp->rdnss_list);

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

                if (addr == NULL && rdnss_length == 1) {
                    makeentry(entbuf, sizeof(entbuf), -1, "rdnssaddr");
                    addr = agetstr(entbuf, &bp);
                }

                if (addr == NULL) {
                    syslog(LOG_ERR,
                           "<%s> need %s as a DNS server address for "
                           "interface %s",
                           __func__, entbuf, intface);
                    exit(1);
                }

                if (inet_pton(AF_INET6, addr, &rdnss->addr) != 1) {
                        syslog(LOG_ERR,
                               "<%s> inet_pton failed for %s",
                               __func__, addr);
                        exit(1);
                }
                if (IN6_IS_ADDR_MULTICAST(&rdnss->addr)) {
                        syslog(LOG_ERR,
                               "<%s> multicast address (%s) must "
                               "not be advertised as recursive DNS server",
                               __func__, addr);
                        exit(1);
                }
            }
        }

        /* DNSSL option (RFC6106) */

        /* Parse the DNSSL lifetime from the config */
        MAYHAVE(val, "dnssllifetime", 2 * tmp->maxinterval);
        if (val < tmp->maxinterval || val > (2 * tmp->maxinterval)) {
            syslog(LOG_NOTICE,
                   "<%s> dnssllifetime (%lu) on %s SHOULD "
                   "be between %u and %u", __func__, val,
                   intface, tmp->maxinterval, 2 * tmp->maxinterval);
        }
        tmp->dnssl_lifetime = val;
        tmp->dnssl_option_length = 8; /* 8 bytes for the option header */

        /* Parse the DNSSL domain list from the config */
        if ((dnssl_length = agetnum("dnssldomains")) < 0) {
            tmp->dnssl_length = 0;
        } else {
            tmp->dnssl_length = dnssl_length;

            for (i = (tmp->dnssl_length - 1); i >= 0; i--) {
                unsigned char *dnssl_buf;
                struct dnssl *dnssl;
                int dnssl_len;
                char entbuf[sizeof("dnssldomain") + 20];
                char *domain;
                int domain_len;

                makeentry(entbuf, sizeof(entbuf), i, "dnssldomain");
                domain = agetstr(entbuf, &bp);

                if (domain == NULL && tmp->dnssl_length == 1) {
                    makeentry(entbuf, sizeof(entbuf), -1, "dnssldomain");
                    domain = agetstr(entbuf, &bp);
                }

                if (domain == NULL) {
                    syslog(LOG_ERR,
                           "<%s> need %s as a DNS search domain for "
                           "interface %s",
                           __func__, entbuf, intface);
                    exit(1);
                }

                domain_len = strlen(domain);

                /* Trim off leading dots */
                while (domain_len > 0 && domain[0] == '.') {
                    domain++;
                    domain_len--;
                }

                /* Trim off trailing dots */
                while (domain_len > 0 && domain[domain_len-1] == '.') {
                    domain_len--;
                }

                if (domain_len > 0) {
                    dnssl_len = sizeof(struct dnssl) + domain_len + 1;
                    dnssl_buf = (unsigned char *)malloc(dnssl_len);

                    memset(dnssl_buf, 0, dnssl_len);

                    dnssl = (struct dnssl *)dnssl_buf;
                    insque(dnssl, &tmp->dnssl_list);

                    /* Copy the domain name in at the end of the dnssl struct */
                    memcpy(dnssl_buf + offsetof(struct dnssl, domain), domain,
                           domain_len);

                    /* Add 2 for leading length byte and the trailing 0 byte */
                    tmp->dnssl_option_length += domain_len + 2;
                }
            }

            /* Round up to the next multiple of 8 */
            tmp->dnssl_option_length += (8 - (tmp->dnssl_option_length & 0x7));
        }

        /* okey */
        tmp->next = ralist;
        ralist = tmp;

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

        /* set timer */
        tmp->timer = rtadvd_add_timer(ra_timeout, ra_timer_update,
                                      tmp, tmp);
        ra_timer_update((void *)tmp, &tmp->timer->tm);
        rtadvd_set_timer(&tmp->timer->tm, tmp->timer);
}

void
get_prefix(struct rainfo *rai)
{
        struct ifaddrs *ifap, *ifa;
        struct prefix *pp;
        struct in6_addr *a;
        u_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);
        }

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

                if (strcmp(ifa->ifa_name, rai->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 = (u_char *)&((struct sockaddr_in6 *)ifa->ifa_netmask)->sin6_addr;
                lim = (u_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. */
                if ((pp = malloc(sizeof(*pp))) == NULL) {
                        syslog(LOG_ERR,
                               "<%s> can't get allocate buffer for prefix",
                               __func__);
                        exit(1);
                }
                memset(pp, 0, sizeof(*pp));

                /* set prefix, sweep bits outside of prefixlen */
                pp->prefixlen = plen;
                memcpy(&pp->prefix, a, sizeof(*a));
                p = (u_char *)&pp->prefix;
                ep = (u_char *)(&pp->prefix + 1);
                while (m < lim && p < ep)
                        *p++ &= *m++;
                while (p < ep)
                        *p++ = 0x00;
                if (!inet_ntop(AF_INET6, &pp->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, pp->prefixlen, rai->ifname);

                /* set other fields with protocol defaults */
                pp->validlifetime = DEF_ADVVALIDLIFETIME;
                pp->preflifetime = DEF_ADVPREFERREDLIFETIME;
                pp->onlinkflg = 1;
                pp->autoconfflg = 1;
                pp->origin = PREFIX_FROM_KERNEL;
                pp->rainfo = rai;

                /* link into chain */
                insque(pp, &rai->prefix);

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

        freeifaddrs(ifap);
}

static void
makeentry(buf, len, id, string)
        char *buf;
        size_t len;
        int id;
        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 *prefix;
        char ntopbuf[INET6_ADDRSTRLEN];

        if ((prefix = malloc(sizeof(*prefix))) == NULL) {
                syslog(LOG_ERR, "<%s> memory allocation failed",
                       __func__);
                return;         /* XXX: error or exit? */
        }
        memset(prefix, 0, sizeof(*prefix));
        prefix->prefix = ipr->ipr_prefix.sin6_addr;
        prefix->prefixlen = ipr->ipr_plen;
        prefix->validlifetime = ipr->ipr_vltime;
        prefix->preflifetime = ipr->ipr_pltime;
        prefix->onlinkflg = ipr->ipr_raf_onlink;
        prefix->autoconfflg = ipr->ipr_raf_auto;
        prefix->origin = PREFIX_FROM_DYNAMIC;

        insque(prefix, &rai->prefix);
        prefix->rainfo = rai;

        syslog(LOG_DEBUG, "<%s> new prefix %s/%d was added on %s",
               __func__, inet_ntop(AF_INET6, &ipr->ipr_prefix.sin6_addr,
                                       ntopbuf, INET6_ADDRSTRLEN),
               ipr->ipr_plen, rai->ifname);

        /* free the previous packet */
        free(rai->ra_data);
        rai->ra_data = NULL;

        /* reconstruct the packet */
        rai->pfxs++;
        make_packet(rai);
}

/*
 * 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 *prefix)
{
        char ntopbuf[INET6_ADDRSTRLEN];
        struct rainfo *rai = prefix->rainfo;

        remque(prefix);
        syslog(LOG_DEBUG, "<%s> prefix %s/%d was deleted on %s",
               __func__, inet_ntop(AF_INET6, &prefix->prefix,
                                       ntopbuf, INET6_ADDRSTRLEN),
               prefix->prefixlen, rai->ifname);
        if (prefix->timer)
                rtadvd_remove_timer(&prefix->timer);
        free(prefix);
        rai->pfxs--;
}

void
invalidate_prefix(struct prefix *prefix)
{
        char ntopbuf[INET6_ADDRSTRLEN];
        struct timeval timo;
        struct rainfo *rai = prefix->rainfo;

        if (prefix->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, &prefix->prefix, ntopbuf, INET6_ADDRSTRLEN),
            prefix->prefixlen, rai->ifname, (long)prefix_timo);

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

static struct rtadvd_timer *
prefix_timeout(void *arg)
{
        struct prefix *prefix = (struct prefix *)arg;
        
        delete_prefix(prefix);

        return(NULL);
}

void
update_prefix(struct prefix * prefix)
{
        char ntopbuf[INET6_ADDRSTRLEN];
        struct rainfo *rai = prefix->rainfo;

        if (prefix->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, &prefix->prefix, ntopbuf,
            INET6_ADDRSTRLEN), prefix->prefixlen, rai->ifname);

        /* stop the expiration timer */
        rtadvd_remove_timer(&prefix->timer);
}

/*
 * 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 *rainfo)
{
        size_t packlen, lladdroptlen = 0;
        u_char *buf;
        struct nd_router_advert *ra;
        struct nd_opt_prefix_info *ndopt_pi;
        struct nd_opt_mtu *ndopt_mtu;
#ifdef ROUTEINFO
        struct nd_opt_route_info *ndopt_rti;
        struct rtinfo *rti;
#endif
        struct prefix *pfx;

        /* calculate total length */
        packlen = sizeof(struct nd_router_advert);
        if (rainfo->advlinkopt) {
                if ((lladdroptlen = lladdropt_length(rainfo->sdl)) == 0) {
                        syslog(LOG_INFO,
                               "<%s> link-layer address option has"
                               " null length on %s.  Treat as not included.",
                               __func__, rainfo->ifname);
                        rainfo->advlinkopt = 0;
                }
                packlen += lladdroptlen;
        }
        if (rainfo->pfxs)
                packlen += sizeof(struct nd_opt_prefix_info) * rainfo->pfxs;
        if (rainfo->linkmtu)
                packlen += sizeof(struct nd_opt_mtu);
#ifdef ROUTEINFO
        for (rti = rainfo->route.next; rti != &rainfo->route; rti = rti->next)
                packlen += sizeof(struct nd_opt_route_info) + 
                           ((rti->prefixlen + 0x3f) >> 6) * 8;
#endif
        if (rainfo->rdnss_length > 0)
                packlen += 8 + sizeof(struct in6_addr) * rainfo->rdnss_length;

        if (rainfo->dnssl_length > 0) {
                packlen += rainfo->dnssl_option_length;
        }

        /* 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);
        }
        if (rainfo->ra_data) {
                /* free the previous packet */
                free(rainfo->ra_data);
                rainfo->ra_data = NULL;
        }
        rainfo->ra_data = buf;
        /* XXX: what if packlen > 576? */
        rainfo->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 = (u_int8_t)(0xff & rainfo->hoplimit);
        ra->nd_ra_flags_reserved = 0; /* just in case */
        /*
         * XXX: the router preference field, which is a 2-bit field, should be
         * initialized before other fields.
         */
        ra->nd_ra_flags_reserved = 0xff & rainfo->rtpref;
        ra->nd_ra_flags_reserved |=
                rainfo->managedflg ? ND_RA_FLAG_MANAGED : 0;
        ra->nd_ra_flags_reserved |=
                rainfo->otherflg ? ND_RA_FLAG_OTHER : 0;
        ra->nd_ra_router_lifetime = htons(rainfo->lifetime);
        ra->nd_ra_reachable = htonl(rainfo->reachabletime);
        ra->nd_ra_retransmit = htonl(rainfo->retranstimer);
        buf += sizeof(*ra);

        if (rainfo->advlinkopt) {
                lladdropt_fill(rainfo->sdl, (struct nd_opt_hdr *)buf);
                buf += lladdroptlen;
        }

        if (rainfo->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(rainfo->linkmtu);
                buf += sizeof(struct nd_opt_mtu);
        }

        for (pfx = rainfo->prefix.next;
             pfx != &rainfo->prefix; pfx = pfx->next) {
                u_int32_t vltime, pltime;
                struct timeval 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->prefixlen;
                ndopt_pi->nd_opt_pi_flags_reserved = 0;
                if (pfx->onlinkflg)
                        ndopt_pi->nd_opt_pi_flags_reserved |=
                                ND_OPT_PI_FLAG_ONLINK;
                if (pfx->autoconfflg)
                        ndopt_pi->nd_opt_pi_flags_reserved |=
                                ND_OPT_PI_FLAG_AUTO;
                if (pfx->timer)
                        vltime = 0;
                else {
                        if (pfx->vltimeexpire || pfx->pltimeexpire)
                                gettimeofday(&now, NULL);
                        if (pfx->vltimeexpire == 0)
                                vltime = pfx->validlifetime;
                        else
                                vltime = (pfx->vltimeexpire > now.tv_sec) ?
                                    pfx->vltimeexpire - now.tv_sec : 0;
                }
                if (pfx->timer)
                        pltime = 0;
                else {
                        if (pfx->pltimeexpire == 0)
                                pltime = pfx->preflifetime;
                        else
                                pltime = (pfx->pltimeexpire > now.tv_sec) ? 
                                    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->prefix;

                buf += sizeof(struct nd_opt_prefix_info);
        }

#ifdef ROUTEINFO
        for (rti = rainfo->route.next; rti != &rainfo->route; rti = rti->next) {
                u_int8_t psize = (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->prefixlen;
                ndopt_rti->nd_opt_rti_flags = 0xff & rti->rtpref;
                ndopt_rti->nd_opt_rti_lifetime = htonl(rti->ltime);
                memcpy(ndopt_rti + 1, &rti->prefix, psize * 8);
                buf += sizeof(struct nd_opt_route_info) + psize * 8;
        }
#endif

        if (rainfo->rdnss_length > 0) { 
                struct nd_opt_rdnss *   ndopt_rdnss;
                struct rdnss *          rdnss;

                ndopt_rdnss = (struct nd_opt_rdnss*) buf;
                ndopt_rdnss->nd_opt_rdnss_type = ND_OPT_RDNSS;
                ndopt_rdnss->nd_opt_rdnss_len = 1 + (rainfo->rdnss_length * 2);
                ndopt_rdnss->nd_opt_rdnss_reserved = 0;
                ndopt_rdnss->nd_opt_rdnss_lifetime = htonl(rainfo->rdnss_lifetime);
                buf += 8;
                
                for (rdnss = rainfo->rdnss_list.next;
                     rdnss != &rainfo->rdnss_list;
                     rdnss = rdnss->next)
                {
                        struct in6_addr* addr6 = (struct in6_addr*) buf;
                        *addr6 = rdnss->addr;
                        buf += sizeof *addr6;
                }
        }

        if (rainfo->dnssl_length > 0) {
                struct nd_opt_dnssl *   dnssl_opt;
                struct dnssl *          dnssl;
                int                     domains_length = 0;
                u_char *                cursor = buf;

                memset(cursor, 0, rainfo->dnssl_option_length);

                dnssl_opt = (struct nd_opt_dnssl *)cursor;
                dnssl_opt->nd_opt_dnssl_type = ND_OPT_DNSSL;
                /*
                 * Length is in units of 8 octets. Divide total byte length
                 * of the option by 8.
                 */
                dnssl_opt->nd_opt_dnssl_len = rainfo->dnssl_option_length >> 3;
                dnssl_opt->nd_opt_dnssl_reserved = 0;
                dnssl_opt->nd_opt_dnssl_lifetime =
                    htonl(rainfo->dnssl_lifetime);

                cursor += offsetof(struct nd_opt_dnssl, nd_opt_dnssl_domains);

                for (dnssl = rainfo->dnssl_list.next;
                     dnssl != &rainfo->dnssl_list;
                     dnssl = dnssl->next)
                {
                        int encodeLen = encode_domain(dnssl->domain, cursor);
                        cursor += encodeLen;
                        domains_length += encodeLen;
                }

                buf += rainfo->dnssl_option_length;
        }

        return;
}

static 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, sizeof(mib)/sizeof(mib[0]), &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);
}

/*
 * Encode a domain name into a buffer according to the rules in RFC 1035 section
 * 3.1. Do not use the compression techniques outlined in section 4.1.4.
 */
int
encode_domain(char *domain, u_char *dst)
{
        char *domainCopy = strdup(domain);
        char *input = domainCopy;
        char *label;
        u_char *cursor = dst;

        while ((label = strsep(&input, ".")) != NULL) {
                int label_len = strlen(label) & 0x3f; /* Max length is 63 */
                if (label_len > 0) {
                        *cursor = (u_char)label_len;
                        cursor++;
                        memcpy(cursor, label, label_len);
                        cursor += label_len;
                }
        }
        *cursor = 0;
        cursor++;

        free(domainCopy);

        return (cursor - dst);
}