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icmp6.c

//==========================================================================
//
//      src/sys/netinet6/icmp6.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*    $KAME: icmp6.c,v 1.269 2001/12/18 02:19:16 jinmei Exp $     */

/*
 * Copyright (C) 1995, 1996, 1997, and 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.
 */

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *    The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *    @(#)ip_icmp.c     8.2 (Berkeley) 1/4/94
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/domain.h>

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

#include <netinet/in.h>
#include <netinet/in_var.h>
#if defined(__OpenBSD__) || (defined(__bsdi__) && _BSDI_VERSION >= 199802)
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#endif
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/mld6_var.h>
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
#include <netinet/in_pcb.h>
#include <netinet6/in6_pcb.h>
#elif defined(__OpenBSD__) || (defined(__bsdi__) && _BSDI_VERSION >= 199802)
#include <netinet/in_pcb.h>
#else
#include <netinet6/in6_pcb.h>
#endif
#include <netinet6/nd6.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/ip6protosw.h>

#ifdef __OpenBSD__ /* KAME IPSEC */
#undef IPSEC
#endif

#ifdef IPSEC
#include <netinet6/ipsec.h>
#include <netkey/key.h>
#endif

#ifdef MIP6
#include <netinet6/mip6.h>
#endif

#ifdef HAVE_NRL_INPCB
/* inpcb members */
#define in6pcb          inpcb
#define in6p_laddr      inp_laddr6
#define in6p_faddr      inp_faddr6
#define in6p_icmp6filt  inp_icmp6filt
#define in6p_route      inp_route
#define in6p_socket     inp_socket
#define in6p_flags      inp_flags
#define in6p_moptions   inp_moptions6
#define in6p_outputopts inp_outputopts6
#define in6p_ip6  inp_ipv6
#define in6p_flowinfo   inp_flowinfo
#define in6p_sp         inp_sp
#define in6p_next inp_next
#define in6p_prev inp_prev

/*
 * for KAME src sync over BSD*'s.  XXX: FreeBSD (>=3) are VERY different from
 * others...
 */
#define in6p_ip6_nxt    inp_ipv6.ip6_nxt
#endif

extern struct domain inet6domain;
extern struct ip6protosw inet6sw[];
extern u_char ip6_protox[];

struct icmp6stat icmp6stat;

#if defined (__OpenBSD__)
extern struct inpcbtable rawin6pcbtable;
#elif !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
extern struct in6pcb rawin6pcb;
#else
extern struct inpcbhead ripcb;
#endif
extern int icmp6errppslim;
static int icmp6errpps_count = 0;
static struct timeval icmp6errppslim_last;
extern int icmp6_nodeinfo;
#if defined(__NetBSD__) || defined(__OpenBSD__)
/*
 * List of callbacks to notify when Path MTU changes are made.
 */
struct icmp6_mtudisc_callback {
      LIST_ENTRY(icmp6_mtudisc_callback) mc_list;
      void (*mc_func) __P((struct in6_addr *));
};

LIST_HEAD(, icmp6_mtudisc_callback) icmp6_mtudisc_callbacks =
    LIST_HEAD_INITIALIZER(&icmp6_mtudisc_callbacks);

static struct rttimer_queue *icmp6_mtudisc_timeout_q = NULL;
extern int pmtu_expire;

/* XXX do these values make any sense? */
static int icmp6_mtudisc_hiwat = 1280;
static int icmp6_mtudisc_lowat = 256;

/*
 * keep track of # of redirect routes.
 */
static struct rttimer_queue *icmp6_redirect_timeout_q = NULL;

/* XXX do these values make any sense? */
static int icmp6_redirect_hiwat = 1280;
static int icmp6_redirect_lowat = 1024;
#endif

static void icmp6_errcount __P((struct icmp6errstat *, int, int));
static int icmp6_rip6_input __P((struct mbuf **, int));
static int icmp6_ratelimit __P((const struct in6_addr *, const int, const int));
static const char *icmp6_redirect_diag __P((struct in6_addr *,
      struct in6_addr *, struct in6_addr *));
#ifndef HAVE_PPSRATECHECK
static int ppsratecheck __P((struct timeval *, int *, int));
#endif
static struct mbuf *ni6_input __P((struct mbuf *, int));
static struct mbuf *ni6_nametodns __P((const char *, int, int));
static int ni6_dnsmatch __P((const char *, int, const char *, int));
static int ni6_addrs __P((struct icmp6_nodeinfo *, struct mbuf *,
                    struct ifnet **, char *));
static int ni6_store_addrs __P((struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
                        struct ifnet *, int));
static int icmp6_notify_error __P((struct mbuf *, int, int, int));
static int icmp6_recover_src __P((struct mbuf *));
#if defined(__NetBSD__) || defined(__OpenBSD__)
static struct rtentry *icmp6_mtudisc_clone __P((struct sockaddr *));
static void icmp6_mtudisc_timeout __P((struct rtentry *, struct rttimer *));
static void icmp6_redirect_timeout __P((struct rtentry *, struct rttimer *));
#endif

void
icmp6_init()
{
      mld6_init();
#if defined(__NetBSD__) || defined(__OpenBSD__)
      icmp6_mtudisc_timeout_q = rt_timer_queue_create(pmtu_expire);
      icmp6_redirect_timeout_q = rt_timer_queue_create(icmp6_redirtimeout);
#endif
}

static void
icmp6_errcount(stat, type, code)
      struct icmp6errstat *stat;
      int type, code;
{
      switch (type) {
      case ICMP6_DST_UNREACH:
            switch (code) {
            case ICMP6_DST_UNREACH_NOROUTE:
                  stat->icp6errs_dst_unreach_noroute++;
                  return;
            case ICMP6_DST_UNREACH_ADMIN:
                  stat->icp6errs_dst_unreach_admin++;
                  return;
            case ICMP6_DST_UNREACH_BEYONDSCOPE:
                  stat->icp6errs_dst_unreach_beyondscope++;
                  return;
            case ICMP6_DST_UNREACH_ADDR:
                  stat->icp6errs_dst_unreach_addr++;
                  return;
            case ICMP6_DST_UNREACH_NOPORT:
                  stat->icp6errs_dst_unreach_noport++;
                  return;
            }
            break;
      case ICMP6_PACKET_TOO_BIG:
            stat->icp6errs_packet_too_big++;
            return;
      case ICMP6_TIME_EXCEEDED:
            switch (code) {
            case ICMP6_TIME_EXCEED_TRANSIT:
                  stat->icp6errs_time_exceed_transit++;
                  return;
            case ICMP6_TIME_EXCEED_REASSEMBLY:
                  stat->icp6errs_time_exceed_reassembly++;
                  return;
            }
            break;
      case ICMP6_PARAM_PROB:
            switch (code) {
            case ICMP6_PARAMPROB_HEADER:
                  stat->icp6errs_paramprob_header++;
                  return;
            case ICMP6_PARAMPROB_NEXTHEADER:
                  stat->icp6errs_paramprob_nextheader++;
                  return;
            case ICMP6_PARAMPROB_OPTION:
                  stat->icp6errs_paramprob_option++;
                  return;
            }
            break;
      case ND_REDIRECT:
            stat->icp6errs_redirect++;
            return;
      }
      stat->icp6errs_unknown++;
}

#if defined(__NetBSD__) || defined(__OpenBSD__)
/*
 * Register a Path MTU Discovery callback.
 */
void
icmp6_mtudisc_callback_register(func)
      void (*func) __P((struct in6_addr *));
{
      struct icmp6_mtudisc_callback *mc;

      for (mc = LIST_FIRST(&icmp6_mtudisc_callbacks); mc != NULL;
           mc = LIST_NEXT(mc, mc_list)) {
            if (mc->mc_func == func)
                  return;
      }

      mc = malloc(sizeof(*mc), M_PCB, M_NOWAIT);
      if (mc == NULL)
            panic("icmp6_mtudisc_callback_register");

      mc->mc_func = func;
      LIST_INSERT_HEAD(&icmp6_mtudisc_callbacks, mc, mc_list);
}
#endif

/*
 * Generate an error packet of type error in response to bad IP6 packet.
 */
void
icmp6_error(m, type, code, param)
      struct mbuf *m;
      int type, code, param;
{
      struct ip6_hdr *oip6, *nip6;
      struct icmp6_hdr *icmp6;
      struct mbuf *n;
      struct ip6aux *ip6a;
      struct in6_addr nip6_src, *nip6_srcp;
      u_int preplen;
      int off;
      int nxt;

      icmp6stat.icp6s_error++;

      /* count per-type-code statistics */
      icmp6_errcount(&icmp6stat.icp6s_outerrhist, type, code);

#ifdef M_DECRYPTED      /* not openbsd */
      if (m->m_flags & M_DECRYPTED) {
            icmp6stat.icp6s_canterror++;
            goto freeit;
      }
#endif

#ifndef PULLDOWN_TEST
      IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
#else
      if (m->m_len < sizeof(struct ip6_hdr)) {
            m = m_pullup(m, sizeof(struct ip6_hdr));
            if (m == NULL)
                  return;
      }
#endif
      oip6 = mtod(m, struct ip6_hdr *);

      /*
       * If the destination address of the erroneous packet is a multicast
       * address, or the packet was sent using link-layer multicast,
       * we should basically suppress sending an error (RFC 2463, Section
       * 2.4).
       * We have two exceptions (the item e.2 in that section):
       * - the Pakcet Too Big message can be sent for path MTU discovery.
       * - the Parameter Problem Message that can be allowed an icmp6 error
       *   in the option type field.  This check has been done in
       *   ip6_unknown_opt(), so we can just check the type and code.
       */
      if ((m->m_flags & (M_BCAST|M_MCAST) ||
           IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
          (type != ICMP6_PACKET_TOO_BIG &&
           (type != ICMP6_PARAM_PROB ||
            code != ICMP6_PARAMPROB_OPTION)))
            goto freeit;

      /*
       * RFC 2463, 2.4 (e.5): source address check.
       * XXX: the case of anycast source?
       */
      if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
          IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
            goto freeit;

      /*
       * If we are about to send ICMPv6 against ICMPv6 error/redirect,
       * don't do it.
       */
      nxt = -1;
      off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
      if (off >= 0 && nxt == IPPROTO_ICMPV6) {
            struct icmp6_hdr *icp;

#ifndef PULLDOWN_TEST
            IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct icmp6_hdr), );
            icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
#else
            IP6_EXTHDR_GET(icp, struct icmp6_hdr *, m, off,
                  sizeof(*icp));
            if (icp == NULL) {
                  icmp6stat.icp6s_tooshort++;
                  return;
            }
#endif
            if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
                icp->icmp6_type == ND_REDIRECT) {
                  /*
                   * ICMPv6 error
                   * Special case: for redirect (which is
                   * informational) we must not send icmp6 error.
                   */
                  icmp6stat.icp6s_canterror++;
                  goto freeit;
            } else {
                  /* ICMPv6 informational - send the error */
            }
      }
#if 0 /* controversial */
      else if (off >= 0 && nxt == IPPROTO_ESP) {
            /*
             * It could be ICMPv6 error inside ESP.  Take a safer side,
             * don't respond.
             */
            icmp6stat.icp6s_canterror++;
            goto freeit;
      }
#endif
      else {
            /* non-ICMPv6 - send the error */
      }

      oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */

      /* Finally, do rate limitation check. */
      if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
            icmp6stat.icp6s_toofreq++;
            goto freeit;
      }

      /*
       * OK, ICMP6 can be generated.
       */

      /*
       * Recover the original ip6_src if the src and the homeaddr
       * have been swapped while dest6 processing (see dest6.c).  To
       * avoid m_pulldown, we had better to swap addresses before
       * m_prepend below.
       *
       * XXX: We should consider the other candidate to keep the
       * icmp6 error packet correct that not swapping ip6_src and
       * homeaddr in the dest6 processing.
       */
      nip6_srcp = &oip6->ip6_src;
      n = ip6_findaux(m);
      if (n != NULL) {
            ip6a = mtod(n, struct ip6aux *);
            if ((ip6a->ip6a_flags & IP6A_HASEEN) != 0 &&
                (ip6a->ip6a_flags & IP6A_SWAP) != 0) {
                  nip6_src = oip6->ip6_src;
                  nip6_srcp = &nip6_src;
                  if (icmp6_recover_src(m)) {
                        /* mbuf is freed in icmp6_recover_src */
                        return;
                  }
                  oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */
            }
      }

      if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
            m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);

      preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
      M_PREPEND(m, preplen, M_DONTWAIT);
      if (m && m->m_len < preplen)
            m = m_pullup(m, preplen);
      if (m == NULL) {
            nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
            return;
      }

      nip6 = mtod(m, struct ip6_hdr *);
      nip6->ip6_src  = *nip6_srcp;
      nip6->ip6_dst  = oip6->ip6_dst;

      if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
            oip6->ip6_src.s6_addr16[1] = 0;
      if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
            oip6->ip6_dst.s6_addr16[1] = 0;

      icmp6 = (struct icmp6_hdr *)(nip6 + 1);
      icmp6->icmp6_type = type;
      icmp6->icmp6_code = code;
      icmp6->icmp6_pptr = htonl((u_int32_t)param);

      /*
       * icmp6_reflect() is designed to be in the input path.
       * icmp6_error() can be called from both input and outut path,
       * and if we are in output path rcvif could contain bogus value.
       * clear m->m_pkthdr.rcvif for safety, we should have enough scope
       * information in ip header (nip6).
       */
      m->m_pkthdr.rcvif = NULL;

      icmp6stat.icp6s_outhist[type]++;
      icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */

      return;

  freeit:
      /*
       * If we can't tell wheter or not we can generate ICMP6, free it.
       */
      m_freem(m);
}

/*
 * Process a received ICMP6 message.
 */
int
icmp6_input(mp, offp, proto)
      struct mbuf **mp;
      int *offp, proto;
{
      struct mbuf *m = *mp, *n;
      struct ip6_hdr *ip6, *nip6;
      struct icmp6_hdr *icmp6, *nicmp6;
      int off = *offp;
      int icmp6len = m->m_pkthdr.len - *offp;
      int code, sum, noff;

      icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_msg);

#ifndef PULLDOWN_TEST
      IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_hdr), IPPROTO_DONE);
      /* m might change if M_LOOP.  So, call mtod after this */
#endif

      /*
       * Locate icmp6 structure in mbuf, and check
       * that not corrupted and of at least minimum length
       */

      ip6 = mtod(m, struct ip6_hdr *);
      if (icmp6len < sizeof(struct icmp6_hdr)) {
            icmp6stat.icp6s_tooshort++;
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_error);
            goto freeit;
      }

      /*
       * calculate the checksum
       */
#ifndef PULLDOWN_TEST
      icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
#else
      IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
      if (icmp6 == NULL) {
            icmp6stat.icp6s_tooshort++;
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_error);
            return IPPROTO_DONE;
      }
#endif
      code = icmp6->icmp6_code;

      if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
            nd6log((LOG_ERR,
                "ICMP6 checksum error(%d|%x) %s\n",
                icmp6->icmp6_type, sum, ip6_sprintf(&ip6->ip6_src)));
            icmp6stat.icp6s_checksum++;
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_error);
            goto freeit;
      }

#if defined(NFAITH) && 0 < NFAITH
      if (faithprefix(&ip6->ip6_dst)) {
            /*
             * Deliver very specific ICMP6 type only.
             * This is important to deilver TOOBIG.  Otherwise PMTUD
             * will not work.
             */
            switch (icmp6->icmp6_type) {
            case ICMP6_DST_UNREACH:
            case ICMP6_PACKET_TOO_BIG:
            case ICMP6_TIME_EXCEEDED:
                  break;
            default:
                  goto freeit;
            }
      }
#endif

      icmp6stat.icp6s_inhist[icmp6->icmp6_type]++;

#ifdef MIP6
      if (mip6_icmp6_tunnel_input(m, off, icmp6len)) {
            goto freeit;
      }
#endif /* MIP6 */
      switch (icmp6->icmp6_type) {
      case ICMP6_DST_UNREACH:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_dstunreach);
#ifdef MIP6
            if (mip6_icmp6_input(m, off, icmp6len))
                  goto freeit;
#endif /* MIP6 */
            switch (code) {
            case ICMP6_DST_UNREACH_NOROUTE:
                  code = PRC_UNREACH_NET;
                  break;
            case ICMP6_DST_UNREACH_ADMIN:
                  icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_adminprohib);
                  code = PRC_UNREACH_PROTOCOL; /* is this a good code? */
                  break;
            case ICMP6_DST_UNREACH_ADDR:
                  code = PRC_HOSTDEAD;
                  break;
#ifdef COMPAT_RFC1885
            case ICMP6_DST_UNREACH_NOTNEIGHBOR:
                  code = PRC_UNREACH_SRCFAIL;
                  break;
#else
            case ICMP6_DST_UNREACH_BEYONDSCOPE:
                  /* I mean "source address was incorrect." */
                  code = PRC_UNREACH_NET;
                  break;
#endif
            case ICMP6_DST_UNREACH_NOPORT:
                  code = PRC_UNREACH_PORT;
                  break;
            default:
                  goto badcode;
            }
            goto deliver;
            break;

      case ICMP6_PACKET_TOO_BIG:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_pkttoobig);
            if (code != 0)
                  goto badcode;

            code = PRC_MSGSIZE;

            /*
             * Updating the path MTU will be done after examining
             * intermediate extension headers.
             */
            goto deliver;
            break;

      case ICMP6_TIME_EXCEEDED:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_timeexceed);
            switch (code) {
            case ICMP6_TIME_EXCEED_TRANSIT:
                  code = PRC_TIMXCEED_INTRANS;
                  break;
            case ICMP6_TIME_EXCEED_REASSEMBLY:
                  code = PRC_TIMXCEED_REASS;
                  break;
            default:
                  goto badcode;
            }
            goto deliver;
            break;

      case ICMP6_PARAM_PROB:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_paramprob);
            switch (code) {
            case ICMP6_PARAMPROB_NEXTHEADER:
                  code = PRC_UNREACH_PROTOCOL;
                  break;
            case ICMP6_PARAMPROB_HEADER:
            case ICMP6_PARAMPROB_OPTION:
#ifdef MIP6
                  if (mip6_icmp6_input(m, off, icmp6len))
                        goto freeit;
#endif /* MIP6 */
                  code = PRC_PARAMPROB;
                  break;
            default:
                  goto badcode;
            }
            goto deliver;
            break;

      case ICMP6_ECHO_REQUEST:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_echo);
            if (code != 0)
                  goto badcode;
            /*
             * Copy mbuf to send to two data paths: userland socket(s),
             * and to the querier (echo reply).
             * m: a copy for socket, n: a copy for querier
             */
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* Give up local */
                  n = m;
                  m = NULL;
                  goto deliverecho;
            }
            /*
             * If the first mbuf is shared, or the first mbuf is too short,
             * copy the first part of the data into a fresh mbuf.
             * Otherwise, we will wrongly overwrite both copies.
             */
            if ((n->m_flags & M_EXT) != 0 ||
                n->m_len < off + sizeof(struct icmp6_hdr)) {
                  struct mbuf *n0 = n;
                  const int maxlen = sizeof(*nip6) + sizeof(*nicmp6);

                  /*
                   * Prepare an internal mbuf.  m_pullup() doesn't
                   * always copy the length we specified.
                   */
                  if (maxlen >= MCLBYTES) {
                        /* Give up remote */
                        m_freem(n0);
                        break;
                  }
                  MGETHDR(n, M_DONTWAIT, n0->m_type);
                  if (n && maxlen >= MHLEN) {
                        MCLGET(n, M_DONTWAIT);
                        if ((n->m_flags & M_EXT) == 0) {
                              m_free(n);
                              n = NULL;
                        }
                  }
                  if (n == NULL) {
                        /* Give up local */
                        m_freem(n0);
                        n = m;
                        m = NULL;
                        goto deliverecho;
                  }
#ifdef __OpenBSD__
                  M_MOVE_PKTHDR(n, n0);
#else
                  M_COPY_PKTHDR(n, n0);
#endif
                  /*
                   * Copy IPv6 and ICMPv6 only.
                   */
                  nip6 = mtod(n, struct ip6_hdr *);
                  bcopy(ip6, nip6, sizeof(struct ip6_hdr));
                  nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
                  bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
                  noff = sizeof(struct ip6_hdr);
                  n->m_len = noff + sizeof(struct icmp6_hdr);
                  /*
                   * Adjust mbuf.  ip6_plen will be adjusted in
                   * ip6_output().
                   * n->m_pkthdr.len == n0->m_pkthdr.len at this point.
                   */
                  n->m_pkthdr.len += noff + sizeof(struct icmp6_hdr);
                  n->m_pkthdr.len -= (off + sizeof(struct icmp6_hdr));
                  m_adj(n0, off + sizeof(struct icmp6_hdr));
                  n->m_next = n0;
                  n0->m_flags &= ~M_PKTHDR;
            } else {
       deliverecho:
                  nip6 = mtod(n, struct ip6_hdr *);
                  nicmp6 = (struct icmp6_hdr *)((caddr_t)nip6 + off);
                  noff = off;
            }
            nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
            nicmp6->icmp6_code = 0;
            if (n) {
                  icmp6stat.icp6s_reflect++;
                  icmp6stat.icp6s_outhist[ICMP6_ECHO_REPLY]++;
                  icmp6_reflect(n, noff);
            }
            if (!m)
                  goto freeit;
            break;

      case ICMP6_ECHO_REPLY:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_echoreply);
            if (code != 0)
                  goto badcode;
            break;

#ifdef MIP6
      case ICMP6_HADISCOV_REQUEST:
            if (icmp6len < sizeof(struct ha_discov_req))
                  goto badlen;
            if (code != 0)
                  goto badcode;
            if (mip6_icmp6_input(m, off, icmp6len))
                  goto freeit;
            break;
      case ICMP6_HADISCOV_REPLY:
            if (icmp6len < sizeof(struct ha_discov_rep))
                  goto badlen;
            if (code != 0)
                  goto badcode;
            if (mip6_icmp6_input(m, off, icmp6len))
                  goto freeit;
            break;
#ifndef MIP6_DRAFT13
      case ICMP6_MOBILEPREFIX_SOLICIT:
            if (icmp6len < sizeof(struct mobile_prefix_solicit))
                  goto badlen;
            if (code != 0)
                  goto badcode;
            if (mip6_icmp6_input(m, off, icmp6len))
                  goto freeit;
            break;

      case ICMP6_MOBILEPREFIX_ADVERT:
            if (icmp6len < sizeof (struct mobile_prefix_advert))
                  goto badlen;
            if (code != 0)
                  goto badcode;
            if (mip6_icmp6_input(m, off, icmp6len))
                  goto freeit;
            break;
#endif /* !MIP6_DRAFT13 */
#endif /* MIP6 */

      case MLD_LISTENER_QUERY:
      case MLD_LISTENER_REPORT:
            if (icmp6len < sizeof(struct mld_hdr))
                  goto badlen;
            if (icmp6->icmp6_type == MLD_LISTENER_QUERY) /* XXX: ugly... */
                  icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mldquery);
            else
                  icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mldreport);
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* give up local */
                  mld6_input(m, off);
                  m = NULL;
                  goto freeit;
            }
            mld6_input(n, off);
            /* m stays. */
            break;

      case MLD_LISTENER_DONE:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mlddone);
            if (icmp6len < sizeof(struct mld_hdr))    /* necessary? */
                  goto badlen;
            break;            /* nothing to be done in kernel */

      case MLD_MTRACE_RESP:
      case MLD_MTRACE:
            /* XXX: these two are experimental.  not officially defined. */
            /* XXX: per-interface statistics? */
            break;            /* just pass it to applications */

      case ICMP6_WRUREQUEST:  /* ICMP6_FQDN_QUERY */
          {
            enum { WRU, FQDN } mode;

            if (!icmp6_nodeinfo)
                  break;

            if (icmp6len == sizeof(struct icmp6_hdr) + 4)
                  mode = WRU;
            else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
                  mode = FQDN;
            else
                  goto badlen;

#ifdef __FreeBSD__
#define hostnamelen     strlen(hostname)
#endif
            if (mode == FQDN) {
#ifndef PULLDOWN_TEST
                  IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_nodeinfo),
                               IPPROTO_DONE);
#endif
                  n = m_copym(m, 0, M_COPYALL, M_DONTWAIT);
                  if (n)
                        n = ni6_input(n, off);
                  /* XXX meaningless if n == NULL */
                  noff = sizeof(struct ip6_hdr);
            } else {
                  u_char *p;
                  int maxlen, maxhlen;

                  if ((icmp6_nodeinfo & 5) != 5) 
                        break;

                  if (code != 0)
                        goto badcode;
                  maxlen = sizeof(*nip6) + sizeof(*nicmp6) + 4;
                  if (maxlen >= MCLBYTES) {
                        /* Give up remote */
                        break;
                  }
                  MGETHDR(n, M_DONTWAIT, m->m_type);
                  if (n && maxlen > MHLEN) {
                        MCLGET(n, M_DONTWAIT);
                        if ((n->m_flags & M_EXT) == 0) {
                              m_free(n);
                              n = NULL;
                        }
                  }
                  if (n == NULL) {
                        /* Give up remote */
                        break;
                  }
                  n->m_pkthdr.rcvif = NULL;
                  n->m_len = 0;
                  maxhlen = M_TRAILINGSPACE(n) - maxlen;
                  if (maxhlen > hostnamelen)
                        maxhlen = hostnamelen;
                  /*
                   * Copy IPv6 and ICMPv6 only.
                   */
                  nip6 = mtod(n, struct ip6_hdr *);
                  bcopy(ip6, nip6, sizeof(struct ip6_hdr));
                  nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
                  bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
                  p = (u_char *)(nicmp6 + 1);
                  bzero(p, 4);
                  bcopy(hostname, p + 4, maxhlen); /* meaningless TTL */
                  noff = sizeof(struct ip6_hdr);
#ifdef __OpenBSD__
                  M_DUP_PKTHDR(n, m); /* just for rcvif */
#else
                  M_COPY_PKTHDR(n, m); /* just for rcvif */
#endif
                  n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
                        sizeof(struct icmp6_hdr) + 4 + maxhlen;
                  nicmp6->icmp6_type = ICMP6_WRUREPLY;
                  nicmp6->icmp6_code = 0;
            }
#undef hostnamelen
            if (n) {
                  icmp6stat.icp6s_reflect++;
                  icmp6stat.icp6s_outhist[ICMP6_WRUREPLY]++;
                  icmp6_reflect(n, noff);
            }
            break;
          }

      case ICMP6_WRUREPLY:
            if (code != 0)
                  goto badcode;
            break;

      case ND_ROUTER_SOLICIT:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_routersolicit);
            if (code != 0)
                  goto badcode;
            if (icmp6len < sizeof(struct nd_router_solicit))
                  goto badlen;
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* give up local */
                  nd6_rs_input(m, off, icmp6len);
                  m = NULL;
                  goto freeit;
            }
            nd6_rs_input(n, off, icmp6len);
            /* m stays. */
            break;

      case ND_ROUTER_ADVERT:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_routeradvert);
            if (code != 0)
                  goto badcode;
            if (icmp6len < sizeof(struct nd_router_advert))
                  goto badlen;
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* give up local */
                  nd6_ra_input(m, off, icmp6len);
                  m = NULL;
                  goto freeit;
            }
            nd6_ra_input(n, off, icmp6len);
            /* m stays. */
            break;

      case ND_NEIGHBOR_SOLICIT:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_neighborsolicit);
            if (code != 0)
                  goto badcode;
            if (icmp6len < sizeof(struct nd_neighbor_solicit))
                  goto badlen;
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* give up local */
                  nd6_ns_input(m, off, icmp6len);
                  m = NULL;
                  goto freeit;
            }
            nd6_ns_input(n, off, icmp6len);
            /* m stays. */
            break;

      case ND_NEIGHBOR_ADVERT:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_neighboradvert);
            if (code != 0)
                  goto badcode;
            if (icmp6len < sizeof(struct nd_neighbor_advert))
                  goto badlen;
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* give up local */
                  nd6_na_input(m, off, icmp6len);
                  m = NULL;
                  goto freeit;
            }
            nd6_na_input(n, off, icmp6len);
            /* m stays. */
            break;

      case ND_REDIRECT:
            icmp6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_redirect);
            if (code != 0)
                  goto badcode;
            if (icmp6len < sizeof(struct nd_redirect))
                  goto badlen;
            if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
                  /* give up local */
                  icmp6_redirect_input(m, off);
                  m = NULL;
                  goto freeit;
            }
            icmp6_redirect_input(n, off);
            /* m stays. */
            break;

      case ICMP6_ROUTER_RENUMBERING:
            if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
                code != ICMP6_ROUTER_RENUMBERING_RESULT)
                  goto badcode;
            if (icmp6len < sizeof(struct icmp6_router_renum))
                  goto badlen;
            break;

      default:
            nd6log((LOG_DEBUG,
                "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
                icmp6->icmp6_type, ip6_sprintf(&ip6->ip6_src),
                ip6_sprintf(&ip6->ip6_dst),
                m->m_pkthdr.rcvif ? m->m_pkthdr.rcvif->if_index : 0));
            if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
                  /* ICMPv6 error: MUST deliver it by spec... */
                  code = PRC_NCMDS;
                  /* deliver */
            } else {
                  /* ICMPv6 informational: MUST not deliver */
                  break;
            }
      deliver:
            if (icmp6_notify_error(m, off, icmp6len, code)) {
                  /* In this case, m should've been freed. */
                  return(IPPROTO_DONE);
            }
            break;

      badcode:
            icmp6stat.icp6s_badcode++;
            break;

      badlen:
            icmp6stat.icp6s_badlen++;
            break;
      }

      /* deliver the packet to appropriate sockets */
      icmp6_rip6_input(&m, *offp);

      return IPPROTO_DONE;

 freeit:
      m_freem(m);
      return IPPROTO_DONE;
}

static int
icmp6_notify_error(m, off, icmp6len, code)
      struct mbuf *m;
      int off, icmp6len;
{
      struct icmp6_hdr *icmp6;
      struct ip6_hdr *eip6;
      u_int32_t notifymtu;
      int64_t zoneid;
      struct sockaddr_in6 icmp6src, icmp6dst;

      if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
            icmp6stat.icp6s_tooshort++;
            goto freeit;
      }
#ifndef PULLDOWN_TEST
      IP6_EXTHDR_CHECK(m, off,
                   sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr),
                   -1);
      icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
#else
      IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
                   sizeof(*icmp6) + sizeof(struct ip6_hdr));
      if (icmp6 == NULL) {
            icmp6stat.icp6s_tooshort++;
            return(-1);
      }
#endif
      eip6 = (struct ip6_hdr *)(icmp6 + 1);

      /* Detect the upper level protocol */
      {
            void (*ctlfunc) __P((int, struct sockaddr *, void *));
            u_int8_t nxt = eip6->ip6_nxt;
            int eoff = off + sizeof(struct icmp6_hdr) +
                  sizeof(struct ip6_hdr);
            struct ip6ctlparam ip6cp;
            struct in6_addr *finaldst = NULL;
            int icmp6type = icmp6->icmp6_type;
            struct ip6_frag *fh;
            struct ip6_rthdr *rth;
            struct ip6_rthdr0 *rth0;
            int rthlen;

            while (1) { /* XXX: should avoid infinite loop explicitly? */
                  struct ip6_ext *eh;

                  switch (nxt) {
                  case IPPROTO_HOPOPTS:
                  case IPPROTO_DSTOPTS:
                  case IPPROTO_AH:
#ifndef PULLDOWN_TEST
                        IP6_EXTHDR_CHECK(m, 0, eoff +
                                     sizeof(struct ip6_ext),
                                     -1);
                        eh = (struct ip6_ext *)(mtod(m, caddr_t)
                                          + eoff);
#else
                        IP6_EXTHDR_GET(eh, struct ip6_ext *, m,
                                     eoff, sizeof(*eh));
                        if (eh == NULL) {
                              icmp6stat.icp6s_tooshort++;
                              return(-1);
                        }
#endif
                        
                        if (nxt == IPPROTO_AH)
                              eoff += (eh->ip6e_len + 2) << 2;
                        else
                              eoff += (eh->ip6e_len + 1) << 3;
                        nxt = eh->ip6e_nxt;
                        break;
                  case IPPROTO_ROUTING:
                        /*
                         * When the erroneous packet contains a
                         * routing header, we should examine the
                         * header to determine the final destination.
                         * Otherwise, we can't properly update
                         * information that depends on the final
                         * destination (e.g. path MTU).
                         */
#ifndef PULLDOWN_TEST
                        IP6_EXTHDR_CHECK(m, 0, eoff + sizeof(*rth),
                                     -1);
                        rth = (struct ip6_rthdr *)(mtod(m, caddr_t)
                                             + eoff);
#else
                        IP6_EXTHDR_GET(rth, struct ip6_rthdr *, m,
                                     eoff, sizeof(*rth));
                        if (rth == NULL) {
                              icmp6stat.icp6s_tooshort++;
                              return(-1);
                        }
#endif
                        rthlen = (rth->ip6r_len + 1) << 3;
                        /*
                         * XXX: currently there is no
                         * officially defined type other
                         * than type-0.
                         * Note that if the segment left field
                         * is 0, all intermediate hops must
                         * have been passed.
                         */
                        if (rth->ip6r_segleft &&
                            rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
                              int hops;

#ifndef PULLDOWN_TEST
                              IP6_EXTHDR_CHECK(m, 0, eoff + rthlen,
                                           -1);
                              rth0 = (struct ip6_rthdr0 *)(mtod(m, caddr_t) + eoff);
#else
                              IP6_EXTHDR_GET(rth0,
                                           struct ip6_rthdr0 *, m,
                                           eoff, rthlen);
                              if (rth0 == NULL) {
                                    icmp6stat.icp6s_tooshort++;
                                    return(-1);
                              }
#endif
                              /* just ignore a bogus header */
                              if ((rth0->ip6r0_len % 2) == 0 &&
                                  (hops = rth0->ip6r0_len/2))
                                    finaldst = (struct in6_addr *)(rth0 + 1) + (hops - 1);
                        }
                        eoff += rthlen;
                        nxt = rth->ip6r_nxt;
                        break;
                  case IPPROTO_FRAGMENT:
#ifndef PULLDOWN_TEST
                        IP6_EXTHDR_CHECK(m, 0, eoff +
                                     sizeof(struct ip6_frag),
                                     -1);
                        fh = (struct ip6_frag *)(mtod(m, caddr_t)
                                           + eoff);
#else
                        IP6_EXTHDR_GET(fh, struct ip6_frag *, m,
                                     eoff, sizeof(*fh));
                        if (fh == NULL) {
                              icmp6stat.icp6s_tooshort++;
                              return(-1);
                        }
#endif
                        /*
                         * Data after a fragment header is meaningless
                         * unless it is the first fragment, but
                         * we'll go to the notify label for path MTU
                         * discovery.
                         */
                        if (fh->ip6f_offlg & IP6F_OFF_MASK)
                              goto notify;

                        eoff += sizeof(struct ip6_frag);
                        nxt = fh->ip6f_nxt;
                        break;
                  default:
                        /*
                         * This case includes ESP and the No Next
                         * Header.  In such cases going to the notify
                         * label does not have any meaning
                         * (i.e. ctlfunc will be NULL), but we go
                         * anyway since we might have to update
                         * path MTU information.
                         */
                        goto notify;
                  }
            }
        notify:
#ifndef PULLDOWN_TEST
            icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
#else
            IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
                         sizeof(*icmp6) + sizeof(struct ip6_hdr));
            if (icmp6 == NULL) {
                  icmp6stat.icp6s_tooshort++;
                  return(-1);
            }
#endif

            eip6 = (struct ip6_hdr *)(icmp6 + 1);
            bzero(&icmp6dst, sizeof(icmp6dst));
            icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
            icmp6dst.sin6_family = AF_INET6;
            if (finaldst == NULL)
                  icmp6dst.sin6_addr = eip6->ip6_dst;
            else
                  icmp6dst.sin6_addr = *finaldst;
            if ((zoneid = in6_addr2zoneid(m->m_pkthdr.rcvif,
                                    &icmp6dst.sin6_addr)) < 0)
                  goto freeit;
            icmp6dst.sin6_scope_id = zoneid;
            if (in6_embedscope(&icmp6dst.sin6_addr, &icmp6dst)) {
                  /* should be impossbile */
                  nd6log((LOG_DEBUG,
                      "icmp6_notify_error: in6_embedscope failed\n"));
                  goto freeit;
            }

            /*
             * retrieve parameters from the inner IPv6 header, and convert
             * them into sockaddr structures.
             */
            bzero(&icmp6src, sizeof(icmp6src));
            icmp6src.sin6_len = sizeof(struct sockaddr_in6);
            icmp6src.sin6_family = AF_INET6;
            icmp6src.sin6_addr = eip6->ip6_src;
            if ((zoneid = in6_addr2zoneid(m->m_pkthdr.rcvif,
                                    &icmp6src.sin6_addr)) < 0)
                  goto freeit;
            icmp6src.sin6_scope_id = zoneid;
            if (in6_embedscope(&icmp6src.sin6_addr, &icmp6src)) {
                  /* should be impossbile */
                  nd6log((LOG_DEBUG,
                      "icmp6_notify_error: in6_embedscope failed\n"));
                  goto freeit;
            }
            icmp6src.sin6_flowinfo =
                  (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);

            if (finaldst == NULL)
                  finaldst = &eip6->ip6_dst;
            ip6cp.ip6c_m = m;
            ip6cp.ip6c_icmp6 = icmp6;
            ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
            ip6cp.ip6c_off = eoff;
            ip6cp.ip6c_finaldst = finaldst;
            ip6cp.ip6c_src = &icmp6src;
            ip6cp.ip6c_nxt = nxt;

            if (icmp6type == ICMP6_PACKET_TOO_BIG) {
                  notifymtu = ntohl(icmp6->icmp6_mtu);
                  ip6cp.ip6c_cmdarg = (void *)&notifymtu;
#if !(defined(__NetBSD__) || defined(__OpenBSD__))
                  icmp6_mtudisc_update(&ip6cp, 1);    /* XXX */
#endif
            }

            ctlfunc = (void (*) __P((int, struct sockaddr *, void *)))
                  (inet6sw[ip6_protox[nxt]].pr_ctlinput);
            if (ctlfunc) {
                  (void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
                                &ip6cp);
            }
      }
      return(0);

  freeit:
      m_freem(m);
      return(-1);
}

void
icmp6_mtudisc_update(ip6cp, validated)
      struct ip6ctlparam *ip6cp;
      int validated;
{
#if defined(__NetBSD__) || defined(__OpenBSD__)
      unsigned long rtcount;
      struct icmp6_mtudisc_callback *mc;
#endif
      struct in6_addr *dst = ip6cp->ip6c_finaldst;
      struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
      struct mbuf *m = ip6cp->ip6c_m;     /* will be necessary for scope issue */
      u_int mtu = ntohl(icmp6->icmp6_mtu);
      struct rtentry *rt = NULL;
      struct sockaddr_in6 sin6;
#ifdef __bsdi__
#ifdef NEW_STRUCT_ROUTE
      struct route ro6;
#else
      struct route_in6 ro6;
#endif
#endif

#if defined(__NetBSD__) || defined(__OpenBSD__)
      /*
       * allow non-validated cases if memory is plenty, to make traffic
       * from non-connected pcb happy.
       */
      rtcount = rt_timer_count(icmp6_mtudisc_timeout_q);
      if (validated) {
            if (0 <= icmp6_mtudisc_hiwat && rtcount > icmp6_mtudisc_hiwat)
                  return;
            else if (0 <= icmp6_mtudisc_lowat &&
                rtcount > icmp6_mtudisc_lowat) {
                  /*
                   * XXX nuke a victim, install the new one.
                   */
            }
      } else {
            if (0 <= icmp6_mtudisc_lowat && rtcount > icmp6_mtudisc_lowat)
                  return;
      }
#else
      if (!validated)
            return;
#endif

      bzero(&sin6, sizeof(sin6));
      sin6.sin6_family = PF_INET6;
      sin6.sin6_len = sizeof(struct sockaddr_in6);
      sin6.sin6_addr = *dst;
      /* XXX normally, this won't happen */
      if (IN6_IS_ADDR_LINKLOCAL(dst)) {
            sin6.sin6_addr.s6_addr16[1] =
                htons(m->m_pkthdr.rcvif->if_index);
      }
      /* sin6.sin6_scope_id = XXX: should be set if DST is a scoped addr */
#if defined(__NetBSD__) || defined(__OpenBSD__)
      rt = icmp6_mtudisc_clone((struct sockaddr *)&sin6);
#else
#ifdef __FreeBSD__
      rt = rtalloc1((struct sockaddr *)&sin6, 0,
                  RTF_CLONING | RTF_PRCLONING);
#else
#ifdef __bsdi__
      bcopy(&sin6, &ro6.ro_dst, sizeof(struct sockaddr_in6));
      ro6.ro_rt = 0;
      /* rtcalloc((struct route *)&ro6); */
      rtalloc((struct route *)&ro6);
      rt = ro6.ro_rt;
#else
#error no case for this particular operating system
#endif
#endif
#endif

      if (rt && (rt->rt_flags & RTF_HOST)
          && !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
            if (mtu < IPV6_MMTU) {
                        /* xxx */
                  rt->rt_rmx.rmx_locks |= RTV_MTU;
            } else if (mtu < rt->rt_ifp->if_mtu &&
                     rt->rt_rmx.rmx_mtu > mtu) {
                  icmp6stat.icp6s_pmtuchg++;
                  rt->rt_rmx.rmx_mtu = mtu;
            }
      }
      if (rt) { /* XXX: need braces to avoid conflict with else in RTFREE. */
            RTFREE(rt);
      }

#if defined(__NetBSD__) || defined(__OpenBSD__)
      /*
       * Notify protocols that the MTU for this destination
       * has changed.
       */
      for (mc = LIST_FIRST(&icmp6_mtudisc_callbacks); mc != NULL;
           mc = LIST_NEXT(mc, mc_list))
            (*mc->mc_func)(&sin6.sin6_addr);
#endif
}

/*
 * Process a Node Information Query packet, based on
 * draft-ietf-ipngwg-icmp-name-lookups-07.
 * 
 * Spec incompatibilities:
 * - IPv6 Subject address handling
 * - IPv4 Subject address handling support missing
 * - Proxy reply (answer even if it's not for me)
 * - joins NI group address at in6_ifattach() time only, does not cope
 *   with hostname changes by sethostname(3)
 */
#ifdef __FreeBSD__
#define hostnamelen     strlen(hostname)
#endif
#ifndef offsetof        /* XXX */
#define     offsetof(type, member)  ((size_t)(&((type *)0)->member))
#endif
static struct mbuf *
ni6_input(m, off)
      struct mbuf *m;
      int off;
{
      struct icmp6_nodeinfo *ni6, *nni6;
      struct mbuf *n = NULL;
      u_int16_t qtype;
      int subjlen;
      int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
      struct ni_reply_fqdn *fqdn;
      int addrs;        /* for NI_QTYPE_NODEADDR */
      struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
      struct sockaddr_in6 sin6; /* double meaning; ip6_dst and subjectaddr */
      struct sockaddr_in6 sin6_d; /* XXX: we should retrieve this from m_aux */
      struct ip6_hdr *ip6;
      int oldfqdn = 0;  /* if 1, return pascal string (03 draft) */
      char *subj = NULL;
      struct in6_ifaddr *ia6 = NULL;
      int64_t zoneid;

      ip6 = mtod(m, struct ip6_hdr *);
#ifndef PULLDOWN_TEST
      ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
#else
      IP6_EXTHDR_GET(ni6, struct icmp6_nodeinfo *, m, off, sizeof(*ni6));
      if (ni6 == NULL) {
            /* m is already reclaimed */
            return NULL;
      }
#endif

      /*
       * Validate IPv6 destination address.
       *
       * The Responder must discard the Query without further processing
       * unless it is one of the Responder's unicast or anycast addresses, or
       * a link-local scope multicast address which the Responder has joined.
       * [icmp-name-lookups-07, Section 4.]
       */
      bzero(&sin6, sizeof(sin6));
      sin6.sin6_family = AF_INET6;
      sin6.sin6_len = sizeof(struct sockaddr_in6);
      bcopy(&ip6->ip6_dst, &sin6.sin6_addr, sizeof(sin6.sin6_addr));
      /* XXX scopeid */
      if ((ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)&sin6)) != NULL) {
            /* unicast/anycast, fine */
            if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
                (icmp6_nodeinfo & 4) == 0) {
                  nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
                        "a temporary address in %s:%d",
                         __FILE__, __LINE__));
                  goto bad;
            }
      } else if (IN6_IS_ADDR_MC_LINKLOCAL(&sin6.sin6_addr))
            ; /* link-local multicast, fine */
      else
            goto bad;

      /* validate query Subject field. */
      qtype = ntohs(ni6->ni_qtype);
      subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
      switch (qtype) {
      case NI_QTYPE_NOOP:
      case NI_QTYPE_SUPTYPES:
            /* 07 draft */
            if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
                  break;
            /* FALLTHROUGH */
      case NI_QTYPE_FQDN:
      case NI_QTYPE_NODEADDR:
      case NI_QTYPE_IPV4ADDR:
            switch (ni6->ni_code) {
            case ICMP6_NI_SUBJ_IPV6:
#if ICMP6_NI_SUBJ_IPV6 != 0
            case 0:
#endif
                  /*
                   * backward compatibility - try to accept 03 draft
                   * format, where no Subject is present.
                   */
                  if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
                      subjlen == 0) {
                        oldfqdn++;
                        break;
                  }
#if ICMP6_NI_SUBJ_IPV6 != 0
                  if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
                        goto bad;
#endif

                  if (subjlen != sizeof(sin6.sin6_addr))
                        goto bad;

                  /*
                   * Validate Subject address.
                   *
                   * Not sure what exactly "address belongs to the node"
                   * means in the spec, is it just unicast, or what?
                   *
                   * At this moment we consider Subject address as
                   * "belong to the node" if the Subject address equals
                   * to the IPv6 destination address; validation for
                   * IPv6 destination address should have done enough
                   * check for us.
                   *
                   * We do not do proxy at this moment.
                   */
                  /* m_pulldown instead of copy? */
                  m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
                      subjlen, (caddr_t)&sin6.sin6_addr);
                  if ((zoneid = in6_addr2zoneid(m->m_pkthdr.rcvif,
                                          &sin6.sin6_addr)) < 0)
                        goto bad;
                  sin6.sin6_scope_id = zoneid;
                                               
                  if (in6_embedscope(&sin6.sin6_addr, &sin6))
                        goto bad; /* XXX should not happen */
                  bzero(&sin6_d, sizeof(sin6_d));
                  sin6_d.sin6_family = AF_INET6; /* not used, actually */
                  sin6_d.sin6_len = sizeof(sin6_d); /* ditto */
                  sin6_d.sin6_addr = ip6->ip6_dst;
                  if ((zoneid = in6_addr2zoneid(m->m_pkthdr.rcvif,
                                          &ip6->ip6_dst)) < 0)
                        goto bad;
                  sin6_d.sin6_scope_id = zoneid;
                  if (in6_embedscope(&sin6_d.sin6_addr, &sin6_d))
                        goto bad; /* XXX should not happen */
                  subj = (char *)&sin6;
                  if (SA6_ARE_ADDR_EQUAL(&sin6, &sin6_d))
                        break;

                  /*
                   * XXX if we are to allow other cases, we should really
                   * be careful about scope here.
                   * basically, we should disallow queries toward IPv6
                   * destination X with subject Y, if scope(X) > scope(Y).
                   * if we allow scope(X) > scope(Y), it will result in
                   * information leakage across scope boundary.
                   */
                  goto bad;

            case ICMP6_NI_SUBJ_FQDN:
                  /*
                   * Validate Subject name with gethostname(3).
                   *
                   * The behavior may need some debate, since:
                   * - we are not sure if the node has FQDN as
                   *   hostname (returned by gethostname(3)).
                   * - the code does wildcard match for truncated names.
                   *   however, we are not sure if we want to perform
                   *   wildcard match, if gethostname(3) side has
                   *   truncated hostname.
                   */
                  n = ni6_nametodns(hostname, hostnamelen, 0);
                  if (!n || n->m_next || n->m_len == 0)
                        goto bad;
                  IP6_EXTHDR_GET(subj, char *, m,
                      off + sizeof(struct icmp6_nodeinfo), subjlen);
                  if (subj == NULL)
                        goto bad;
                  if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
                              n->m_len)) {
                        goto bad;
                  }
                  m_freem(n);
                  n = NULL;
                  break;

            case ICMP6_NI_SUBJ_IPV4:      /* XXX: to be implemented? */
            default:
                  goto bad;
            }
            break;
      }

      /* refuse based on configuration.  XXX ICMP6_NI_REFUSED? */
      switch (qtype) {
      case NI_QTYPE_FQDN:
            if ((icmp6_nodeinfo & 1) == 0)
                  goto bad;
            break;
      case NI_QTYPE_NODEADDR:
      case NI_QTYPE_IPV4ADDR:
            if ((icmp6_nodeinfo & 2) == 0)
                  goto bad;
            break;
      }

      /* guess reply length */
      switch (qtype) {
      case NI_QTYPE_NOOP:
            break;            /* no reply data */
      case NI_QTYPE_SUPTYPES:
            replylen += sizeof(u_int32_t);
            break;
      case NI_QTYPE_FQDN:
            /* XXX will append an mbuf */
            replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
            break;
      case NI_QTYPE_NODEADDR:
            addrs = ni6_addrs(ni6, m, &ifp, subj);
            if ((replylen += addrs * (sizeof(struct in6_addr) +
                                sizeof(u_int32_t))) > MCLBYTES)
                  replylen = MCLBYTES; /* XXX: will truncate pkt later */
            break;
      case NI_QTYPE_IPV4ADDR:
            /* unsupported - should respond with unknown Qtype? */
            goto bad;
      default:
            /*
             * XXX: We must return a reply with the ICMP6 code
             * `unknown Qtype' in this case.  However we regard the case
             * as an FQDN query for backward compatibility.
             * Older versions set a random value to this field,
             * so it rarely varies in the defined qtypes.
             * But the mechanism is not reliable...
             * maybe we should obsolete older versions.
             */
            qtype = NI_QTYPE_FQDN;
            /* XXX will append an mbuf */
            replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
            oldfqdn++;
            break;
      }

      /* allocate an mbuf to reply. */
      MGETHDR(n, M_DONTWAIT, m->m_type);
      if (n == NULL) {
            m_freem(m);
            return(NULL);
      }
#ifdef __OpenBSD__
      M_DUP_PKTHDR(n, m); /* just for rcvif */
#else
      M_COPY_PKTHDR(n, m); /* just for rcvif */
#endif
      if (replylen > MHLEN) {
            if (replylen > MCLBYTES) {
                  /*
                   * XXX: should we try to allocate more? But MCLBYTES
                   * is probably much larger than IPV6_MMTU...
                   */
                  goto bad;
            }
            MCLGET(n, M_DONTWAIT);
            if ((n->m_flags & M_EXT) == 0) {
                  goto bad;
            }
      }
      n->m_pkthdr.len = n->m_len = replylen;

      /* copy mbuf header and IPv6 + Node Information base headers */
      bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
      nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
      bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));

      /* qtype dependent procedure */
      switch (qtype) {
      case NI_QTYPE_NOOP:
            nni6->ni_code = ICMP6_NI_SUCCESS;
            nni6->ni_flags = 0;
            break;
      case NI_QTYPE_SUPTYPES:
      {
            u_int32_t v;
            nni6->ni_code = ICMP6_NI_SUCCESS;
            nni6->ni_flags = htons(0x0000);     /* raw bitmap */
            /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
            v = (u_int32_t)htonl(0x0000000f);
            bcopy(&v, nni6 + 1, sizeof(u_int32_t));
            break;
      }
      case NI_QTYPE_FQDN:
            nni6->ni_code = ICMP6_NI_SUCCESS;
            fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
                                    sizeof(struct ip6_hdr) +
                                    sizeof(struct icmp6_nodeinfo));
            nni6->ni_flags = 0; /* XXX: meaningless TTL */
            fqdn->ni_fqdn_ttl = 0;  /* ditto. */
            /*
             * XXX do we really have FQDN in variable "hostname"?
             */
            n->m_next = ni6_nametodns(hostname, hostnamelen, oldfqdn);
            if (n->m_next == NULL)
                  goto bad;
            /* XXX we assume that n->m_next is not a chain */
            if (n->m_next->m_next != NULL)
                  goto bad;
            n->m_pkthdr.len += n->m_next->m_len;
            break;
      case NI_QTYPE_NODEADDR:
      {
            int lenlim, copied;

            nni6->ni_code = ICMP6_NI_SUCCESS;
            n->m_pkthdr.len = n->m_len =
                sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
            lenlim = M_TRAILINGSPACE(n);
            copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
            /* XXX: reset mbuf length */
            n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
                  sizeof(struct icmp6_nodeinfo) + copied;
            break;
      }
      default:
            break;            /* XXX impossible! */
      }

      nni6->ni_type = ICMP6_NI_REPLY;
      m_freem(m);
      return(n);

  bad:
      m_freem(m);
      if (n)
            m_freem(n);
      return(NULL);
}
#undef hostnamelen

/*
 * make a mbuf with DNS-encoded string.  no compression support.
 *
 * XXX names with less than 2 dots (like "foo" or "foo.section") will be
 * treated as truncated name (two \0 at the end).  this is a wild guess.
 */
static struct mbuf *
ni6_nametodns(name, namelen, old)
      const char *name;
      int namelen;
      int old;    /* return pascal string if non-zero */
{
      struct mbuf *m;
      char *cp, *ep;
      const char *p, *q;
      int i, len, nterm;

      if (old)
            len = namelen + 1;
      else
            len = MCLBYTES;

      /* because MAXHOSTNAMELEN is usually 256, we use cluster mbuf */
      MGET(m, M_DONTWAIT, MT_DATA);
      if (m && len > MLEN) {
            MCLGET(m, M_DONTWAIT);
            if ((m->m_flags & M_EXT) == 0)
                  goto fail;
      }
      if (!m)
            goto fail;
      m->m_next = NULL;

      if (old) {
            m->m_len = len;
            *mtod(m, char *) = namelen;
            bcopy(name, mtod(m, char *) + 1, namelen);
            return m;
      } else {
            m->m_len = 0;
            cp = mtod(m, char *);
            ep = mtod(m, char *) + M_TRAILINGSPACE(m);

            /* if not certain about my name, return empty buffer */
            if (namelen == 0)
                  return m;

            /*
             * guess if it looks like shortened hostname, or FQDN.
             * shortened hostname needs two trailing "\0".
             */
            i = 0;
            for (p = name; p < name + namelen; p++) {
                  if (*p && *p == '.')
                        i++;
            }
            if (i < 2)
                  nterm = 2;
            else
                  nterm = 1;

            p = name;
            while (cp < ep && p < name + namelen) {
                  i = 0;
                  for (q = p; q < name + namelen && *q && *q != '.'; q++)
                        i++;
                  /* result does not fit into mbuf */
                  if (cp + i + 1 >= ep)
                        goto fail;
                  /*
                   * DNS label length restriction, RFC1035 page 8.
                   * "i == 0" case is included here to avoid returning
                   * 0-length label on "foo..bar".
                   */
                  if (i <= 0 || i >= 64)
                        goto fail;
                  *cp++ = i;
                  bcopy(p, cp, i);
                  cp += i;
                  p = q;
                  if (p < name + namelen && *p == '.')
                        p++;
            }
            /* termination */
            if (cp + nterm >= ep)
                  goto fail;
            while (nterm-- > 0)
                  *cp++ = '\0';
            m->m_len = cp - mtod(m, char *);
            return m;
      }

      panic("should not reach here");
      /* NOTREACHED */

 fail:
      if (m)
            m_freem(m);
      return NULL;
}

/*
 * check if two DNS-encoded string matches.  takes care of truncated
 * form (with \0\0 at the end).  no compression support.
 * XXX upper/lowercase match (see RFC2065)
 */
static int
ni6_dnsmatch(a, alen, b, blen)
      const char *a;
      int alen;
      const char *b;
      int blen;
{
      const char *a0, *b0;
      int l;

      /* simplest case - need validation? */
      if (alen == blen && bcmp(a, b, alen) == 0)
            return 1;

      a0 = a;
      b0 = b;

      /* termination is mandatory */
      if (alen < 2 || blen < 2)
            return 0;
      if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
            return 0;
      alen--;
      blen--;

      while (a - a0 < alen && b - b0 < blen) {
            if (a - a0 + 1 > alen || b - b0 + 1 > blen)
                  return 0;

            if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
                  return 0;
            /* we don't support compression yet */
            if (a[0] >= 64 || b[0] >= 64)
                  return 0;

            /* truncated case */
            if (a[0] == 0 && a - a0 == alen - 1)
                  return 1;
            if (b[0] == 0 && b - b0 == blen - 1)
                  return 1;
            if (a[0] == 0 || b[0] == 0)
                  return 0;

            if (a[0] != b[0])
                  return 0;
            l = a[0];
            if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
                  return 0;
            if (bcmp(a + 1, b + 1, l) != 0)
                  return 0;

            a += 1 + l;
            b += 1 + l;
      }

      if (a - a0 == alen && b - b0 == blen)
            return 1;
      else
            return 0;
}

/*
 * calculate the number of addresses to be returned in the node info reply.
 */
static int
ni6_addrs(ni6, m, ifpp, subj)
      struct icmp6_nodeinfo *ni6;
      struct mbuf *m;
      struct ifnet **ifpp;
      char *subj;
{
      struct ifnet *ifp;
      struct in6_ifaddr *ifa6;
      struct ifaddr *ifa;
      struct sockaddr_in6 *subj_ip6 = NULL; /* XXX pedant */
      int addrs = 0, addrsofif, iffound = 0;
      int niflags = ni6->ni_flags;

      if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
            switch (ni6->ni_code) {
            case ICMP6_NI_SUBJ_IPV6:
                  if (subj == NULL) /* must be impossible... */
                        return(0);
                  subj_ip6 = (struct sockaddr_in6 *)subj;
                  break;
            default:
                  /*
                   * XXX: we only support IPv6 subject address for
                   * this Qtype.
                   */
                  return(0);
            }
      }

#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
      for (ifp = ifnet; ifp; ifp = ifp->if_next)
#else
      for (ifp = TAILQ_FIRST(&ifnet); ifp; ifp = TAILQ_NEXT(ifp, if_list))
#endif
      {
            addrsofif = 0;
#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
            for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
#elif defined(__FreeBSD__) && __FreeBSD__ >= 4
            TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list)
#else
            for (ifa = ifp->if_addrlist.tqh_first; ifa;
                 ifa = ifa->ifa_list.tqe_next)
#endif
            {
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                        continue;
                  ifa6 = (struct in6_ifaddr *)ifa;

                  if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
                      IN6_ARE_ADDR_EQUAL(&subj_ip6->sin6_addr,
                                     &ifa6->ia_addr.sin6_addr))
                        iffound = 1;

                  /*
                   * IPv4-mapped addresses can only be returned by a
                   * Node Information proxy, since they represent
                   * addresses of IPv4-only nodes, which perforce do
                   * not implement this protocol.
                   * [icmp-name-lookups-07, Section 5.4]
                   * So we don't support NI_NODEADDR_FLAG_COMPAT in
                   * this function at this moment.
                   */

                  /* What do we have to do about ::1? */
                  switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
                  case IPV6_ADDR_SCOPE_LINKLOCAL:
                        if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
                              continue;
                        break;
                  case IPV6_ADDR_SCOPE_SITELOCAL:
                        if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
                              continue;
                        break;
                  case IPV6_ADDR_SCOPE_GLOBAL:
                        if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
                              continue;
                        break;
                  default:
                        continue;
                  }

                  /*
                   * check if anycast is okay.
                   * XXX: just experimental.  not in the spec.
                   */
                  if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
                      (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
                        continue; /* we need only unicast addresses */
                  if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
                      (icmp6_nodeinfo & 4) == 0) {
                        continue;
                  }
                  addrsofif++; /* count the address */
            }
            if (iffound) {
                  *ifpp = ifp;
                  return(addrsofif);
            }

            addrs += addrsofif;
      }

      return(addrs);
}

static int
ni6_store_addrs(ni6, nni6, ifp0, resid)
      struct icmp6_nodeinfo *ni6, *nni6;
      struct ifnet *ifp0;
      int resid;
{
#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
      struct ifnet *ifp = ifp0 ? ifp0 : ifnet;
#else
      struct ifnet *ifp = ifp0 ? ifp0 : TAILQ_FIRST(&ifnet);
#endif
      struct in6_ifaddr *ifa6;
      struct ifaddr *ifa;
      struct ifnet *ifp_dep = NULL;
      int copied = 0, allow_deprecated = 0;
      u_char *cp = (u_char *)(nni6 + 1);
      int niflags = ni6->ni_flags;
      u_int32_t ltime;
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
      long time_second = time.tv_sec;
#endif

      if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
            return(0);  /* needless to copy */

  again:

#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
      for (; ifp; ifp = ifp->if_next)
#else
      for (; ifp; ifp = TAILQ_NEXT(ifp, if_list))
#endif
      {
#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
            for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
#else
            for (ifa = ifp->if_addrlist.tqh_first; ifa;
                 ifa = ifa->ifa_list.tqe_next)
#endif
            {
                  if (ifa->ifa_addr->sa_family != AF_INET6)
                        continue;
                  ifa6 = (struct in6_ifaddr *)ifa;

                  if (IFA6_IS_DEPRECATED(ifa6) &&
                      allow_deprecated == 0) {
                        /*
                         * prefererred address should be put before
                         * deprecated addresses.
                         */

                        /* record the interface for later search */
                        if (ifp_dep == NULL)
                              ifp_dep = ifp;

                        continue;
                  }
                  else if (!IFA6_IS_DEPRECATED(ifa6) &&
                         allow_deprecated != 0)
                        continue; /* we now collect deprecated addrs */

                  /* What do we have to do about ::1? */
                  switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
                  case IPV6_ADDR_SCOPE_LINKLOCAL:
                        if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
                              continue;
                        break;
                  case IPV6_ADDR_SCOPE_SITELOCAL:
                        if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
                              continue;
                        break;
                  case IPV6_ADDR_SCOPE_GLOBAL:
                        if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
                              continue;
                        break;
                  default:
                        continue;
                  }

                  /*
                   * check if anycast is okay.
                   * XXX: just experimental.  not in the spec.
                   */
                  if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
                      (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
                        continue;
                  if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
                      (icmp6_nodeinfo & 4) == 0) {
                        continue;
                  }

                  /* now we can copy the address */
                  if (resid < sizeof(struct in6_addr) +
                      sizeof(u_int32_t)) {
                        /*
                         * We give up much more copy.
                         * Set the truncate flag and return.
                         */
                        nni6->ni_flags |=
                              NI_NODEADDR_FLAG_TRUNCATE;
                        return(copied);
                  }

                  /*
                   * Set the TTL of the address.
                   * The TTL value should be one of the following
                   * according to the specification:
                   *
                   * 1. The remaining lifetime of a DHCP lease on the
                   *    address, or
                   * 2. The remaining Valid Lifetime of a prefix from
                   *    which the address was derived through Stateless
                   *    Autoconfiguration.
                   *
                   * Note that we currently do not support stateful
                   * address configuration by DHCPv6, so the former
                   * case can't happen.
                   *
                   * TTL must be 2^31 > TTL >= 0.
                   */
                  if (ifa6->ia6_lifetime.ia6t_expire == 0)
                        ltime = ND6_INFINITE_LIFETIME;
                  else {
                        if (ifa6->ia6_lifetime.ia6t_expire >
                            time_second) {
                              ltime = ifa6->ia6_lifetime.ia6t_expire
                                    - time_second;
                        } else
                              ltime = 0;
                  }
                  if (ltime > 0x7fffffff)
                        ltime = 0x7fffffff;
                  ltime = htonl(ltime);
                  
                  bcopy(&ltime, cp, sizeof(u_int32_t));
                  cp += sizeof(u_int32_t);

                  /* copy the address itself */
                  bcopy(&ifa6->ia_addr.sin6_addr, cp,
                        sizeof(struct in6_addr));
                  /* XXX: KAME link-local hack; remove ifindex */
                  if (IN6_IS_ADDR_LINKLOCAL(&ifa6->ia_addr.sin6_addr))
                        ((struct in6_addr *)cp)->s6_addr16[1] = 0;
                  cp += sizeof(struct in6_addr);
                  
                  resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
                  copied += (sizeof(struct in6_addr) +
                           sizeof(u_int32_t));
            }
            if (ifp0)   /* we need search only on the specified IF */
                  break;
      }

      if (allow_deprecated == 0 && ifp_dep != NULL) {
            ifp = ifp_dep;
            allow_deprecated = 1;

            goto again;
      }

      return(copied);
}

/*
 * XXX almost dup'ed code with rip6_input.
 */
static int
icmp6_rip6_input(mp, off)
      struct      mbuf **mp;
      int   off;
{
      struct mbuf *m = *mp;
      struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
      struct in6pcb *in6p;
      struct in6pcb *last = NULL;
      struct sockaddr_in6 rip6src;
      struct icmp6_hdr *icmp6;
      struct ip6_recvpktopts opts;

#ifndef PULLDOWN_TEST
      /* this is assumed to be safe. */
      icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
#else
      IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
      if (icmp6 == NULL) {
            /* m is already reclaimed */
            return IPPROTO_DONE;
      }
#endif

      bzero(&opts, sizeof(opts));
      bzero(&rip6src, sizeof(rip6src));
      rip6src.sin6_len = sizeof(struct sockaddr_in6);
      rip6src.sin6_family = AF_INET6;
      /* KAME hack: recover scopeid */
      (void)in6_recoverscope(&rip6src, &ip6->ip6_src, m->m_pkthdr.rcvif);

#if defined(__FreeBSD__) && __FreeBSD__ >= 3
      LIST_FOREACH(in6p, &ripcb, inp_list)
#elif defined(__OpenBSD__)
      for (in6p = rawin6pcbtable.inpt_queue.cqh_first;
           in6p != (struct inpcb *)&rawin6pcbtable.inpt_queue;
           in6p = in6p->inp_queue.cqe_next)
#else
      for (in6p = rawin6pcb.in6p_next;
           in6p != &rawin6pcb; in6p = in6p->in6p_next)
#endif
      {
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
            if ((in6p->inp_vflag & INP_IPV6) == 0)
                  continue;
#endif
#ifdef HAVE_NRL_INPCB
            if (!(in6p->in6p_flags & INP_IPV6))
                  continue;
#endif
            if (in6p->in6p_ip6_nxt != IPPROTO_ICMPV6)
                  continue;
            if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr) &&
               !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst))
                  continue;
            if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr) &&
               !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src))
                  continue;
            if (in6p->in6p_icmp6filt
                && ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
                         in6p->in6p_icmp6filt))
                  continue;
            if (last) {
                  struct      mbuf *n;
                  if ((n = m_copy(m, 0, (int)M_COPYALL)) != NULL) {
                        if (last->in6p_flags & IN6P_CONTROLOPTS)
                              ip6_savecontrol(last, ip6, n, &opts,
                                          NULL);
                        /* strip intermediate headers */
                        m_adj(n, off);
                        if (sbappendaddr(&last->in6p_socket->so_rcv,
                                     (struct sockaddr *)&rip6src,
                                     n, opts.head) == 0) {
                              /* should notify about lost packet */
                              m_freem(n);
                              if (opts.head) {
                                    m_freem(opts.head);
                              }
                        } else
                              sorwakeup(last->in6p_socket);
                        bzero(&opts, sizeof(opts));
                  }
            }
            last = in6p;
      }
      if (last) {
            if (last->in6p_flags & IN6P_CONTROLOPTS)
                  ip6_savecontrol(last, ip6, m, &opts, NULL);
            /* strip intermediate headers */
            m_adj(m, off);
            if (sbappendaddr(&last->in6p_socket->so_rcv,
                         (struct sockaddr *)&rip6src,
                         m, opts.head) == 0) {
                  m_freem(m);
                  if (opts.head)
                        m_freem(opts.head);
            } else
                  sorwakeup(last->in6p_socket);
      } else {
            m_freem(m);
            ip6stat.ip6s_delivered--;
      }
      return IPPROTO_DONE;
}

/*
 * Reflect the ip6 packet back to the source.
 * OFF points to the icmp6 header, counted from the top of the mbuf.
 *
 * Note: RFC 1885 required that an echo reply should be truncated if it
 * did not fit in with (return) path MTU, and KAME code supported the
 * behavior.  However, as a clarification after the RFC, this limitation
 * was removed in a revised version of the spec, RFC 2463.  We had kept the
 * old behavior, with a (non-default) ifdef block, while the new version of
 * the spec was an internet-draft status, and even after the new RFC was
 * published.  But it would rather make sense to clean the obsoleted part
 * up, and to make the code simpler at this stage.
 */
void
icmp6_reflect(m, off)
      struct      mbuf *m;
      size_t off;
{
      struct ip6_hdr *ip6;
      struct icmp6_hdr *icmp6;
      struct in6_ifaddr *ia;
      struct in6_addr t, *src = 0;
      int plen;
      int type, code;
      struct ifnet *outif = NULL;
      struct sockaddr_in6 sa6_src, sa6_dst;

      /* too short to reflect */
      if (off < sizeof(struct ip6_hdr)) {
            nd6log((LOG_DEBUG,
                "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
                (u_long)off, (u_long)sizeof(struct ip6_hdr),
                __FILE__, __LINE__));
            goto bad;
      }

      /*
       * If there are extra headers between IPv6 and ICMPv6, strip
       * off that header first.
       */
#ifdef DIAGNOSTIC
      if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
            panic("assumption failed in icmp6_reflect");
#endif
      if (off > sizeof(struct ip6_hdr)) {
            size_t l;
            struct ip6_hdr nip6;

            l = off - sizeof(struct ip6_hdr);
            m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
            m_adj(m, l);
            l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
            if (m->m_len < l) {
                  if ((m = m_pullup(m, l)) == NULL)
                        return;
            }
            bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
      } else /* off == sizeof(struct ip6_hdr) */ {
            size_t l;
            l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
            if (m->m_len < l) {
                  if ((m = m_pullup(m, l)) == NULL)
                        return;
            }
      }
      plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
      ip6 = mtod(m, struct ip6_hdr *);
      ip6->ip6_nxt = IPPROTO_ICMPV6;
      icmp6 = (struct icmp6_hdr *)(ip6 + 1);
      type = icmp6->icmp6_type; /* keep type for statistics */
      code = icmp6->icmp6_code; /* ditto. */

      t = ip6->ip6_dst;
      /*
       * ip6_input() drops a packet if its src is multicast.
       * So, the src is never multicast.
       */
      ip6->ip6_dst = ip6->ip6_src;

      /*
       * XXX: make sure to embed scope zone information, using
       * already embedded IDs or the received interface (if any).
       * Note that rcvif may be NULL.
       * TODO: scoped routing case (XXX).
       */
      bzero(&sa6_src, sizeof(sa6_src));
      sa6_src.sin6_family = AF_INET6;
      sa6_src.sin6_len = sizeof(sa6_src);
      sa6_src.sin6_addr = ip6->ip6_dst;
      in6_recoverscope(&sa6_src, &ip6->ip6_dst, m->m_pkthdr.rcvif);
      in6_embedscope(&sa6_src.sin6_addr, &sa6_src);
      ip6->ip6_dst = sa6_src.sin6_addr;

      bzero(&sa6_dst, sizeof(sa6_dst));
      sa6_dst.sin6_family = AF_INET6;
      sa6_dst.sin6_len = sizeof(sa6_dst);
      sa6_dst.sin6_addr = t;
      in6_recoverscope(&sa6_dst, &t, m->m_pkthdr.rcvif);
      in6_embedscope(&t, &sa6_dst);

      /*
       * If the incoming packet was addressed directly to us (i.e. unicast),
       * use dst as the src for the reply.
       * The IN6_IFF_NOTREADY case would be VERY rare, but is possible
       * (for example) when we encounter an error while forwarding procedure
       * destined to a duplicated address of ours.
       */
      for (ia = in6_ifaddr; ia; ia = ia->ia_next)
            if (IN6_ARE_ADDR_EQUAL(&t, &ia->ia_addr.sin6_addr) &&
                (ia->ia6_flags & (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY)) == 0) {
                  src = &t;
                  break;
            }
      if (ia == NULL && IN6_IS_ADDR_LINKLOCAL(&t) && (m->m_flags & M_LOOP)) {
            /*
             * This is the case if the dst is our link-local address
             * and the sender is also ourselves.
             */
            src = &t;
      }

      if (src == 0) {
            int e;
#ifdef NEW_STRUCT_ROUTE
            struct route ro;
#else
            struct route_in6 ro;
#endif

            /*
             * This case matches to multicasts, our anycast, or unicasts
             * that we do not own.  Select a source address based on the
             * source address of the erroneous packet.
             */
            bzero(&ro, sizeof(ro));
            src = in6_selectsrc(&sa6_src, NULL, NULL, &ro, NULL, NULL, &e);
            if (ro.ro_rt) { /* XXX: see comments in icmp6_mtudisc_update */
                  RTFREE(ro.ro_rt); /* XXX: we could use this */
            }
            if (src == NULL) {
                  nd6log((LOG_DEBUG,
                      "icmp6_reflect: source can't be determined: "
                      "dst=%s, error=%d\n",
                      ip6_sprintf(&sa6_src.sin6_addr), e));
                  goto bad;
            }
      }

      ip6->ip6_src = *src;

      ip6->ip6_flow = 0;
      ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
      ip6->ip6_vfc |= IPV6_VERSION;
      ip6->ip6_nxt = IPPROTO_ICMPV6;
      if (m->m_pkthdr.rcvif) {
            /* XXX: This may not be the outgoing interface */
            ip6->ip6_hlim = nd_ifinfo[m->m_pkthdr.rcvif->if_index].chlim;
      } else
            ip6->ip6_hlim = ip6_defhlim;

      icmp6->icmp6_cksum = 0;
      icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
                              sizeof(struct ip6_hdr), plen);

      /*
       * XXX option handling
       */

      m->m_flags &= ~(M_BCAST|M_MCAST);
#ifdef IPSEC
      /* Don't lookup socket */
      (void)ipsec_setsocket(m, NULL);
#endif /* IPSEC */

      /*
       * To avoid a "too big" situation at an intermediate router
       * and the path MTU discovery process, specify the IPV6_MINMTU flag.
       * Note that only echo and node information replies are affected,
       * since the length of ICMP6 errors is limited to the minimum MTU.
       */
      if (ip6_output(m, NULL, NULL, IPV6_MINMTU, NULL, &outif) != 0 && outif)
            icmp6_ifstat_inc(outif, ifs6_out_error);

      if (outif)
            icmp6_ifoutstat_inc(outif, type, code);

      return;

 bad:
      m_freem(m);
      return;
}

void
icmp6_fasttimo()
{

      mld6_fasttimeo();
}

static const char *
icmp6_redirect_diag(src6, dst6, tgt6)
      struct in6_addr *src6;
      struct in6_addr *dst6;
      struct in6_addr *tgt6;
{
      static char buf[1024];
#ifndef __bsdi__
      snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
            ip6_sprintf(src6), ip6_sprintf(dst6), ip6_sprintf(tgt6));
#else
      sprintf(buf, "(src=%s dst=%s tgt=%s)",
            ip6_sprintf(src6), ip6_sprintf(dst6), ip6_sprintf(tgt6));
#endif
      return buf;
}

void
icmp6_redirect_input(m, off)
      struct mbuf *m;
      int off;
{
      struct ifnet *ifp = m->m_pkthdr.rcvif;
      struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
      struct nd_redirect *nd_rd;
      int icmp6len = ntohs(ip6->ip6_plen);
      char *lladdr = NULL;
      int lladdrlen = 0;
      u_char *redirhdr = NULL;
      int redirhdrlen = 0;
      struct rtentry *rt = NULL;
      int is_router;
      int is_onlink;
      struct in6_addr src6 = ip6->ip6_src;
      struct in6_addr redtgt6;
      struct in6_addr reddst6;
      union nd_opts ndopts;

      if (!m || !ifp)
            return;

      /* XXX if we are router, we don't update route by icmp6 redirect */
      if (ip6_forwarding)
            goto freeit;
      if (!icmp6_rediraccept)
            goto freeit;

#ifndef PULLDOWN_TEST
      IP6_EXTHDR_CHECK(m, off, icmp6len,);
      nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
#else
      IP6_EXTHDR_GET(nd_rd, struct nd_redirect *, m, off, icmp6len);
      if (nd_rd == NULL) {
            icmp6stat.icp6s_tooshort++;
            return;
      }
#endif
      redtgt6 = nd_rd->nd_rd_target;
      reddst6 = nd_rd->nd_rd_dst;

      if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
            redtgt6.s6_addr16[1] = htons(ifp->if_index);
      if (IN6_IS_ADDR_LINKLOCAL(&reddst6))
            reddst6.s6_addr16[1] = htons(ifp->if_index);

      /* validation */
      if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
            nd6log((LOG_ERR,
                  "ICMP6 redirect sent from %s rejected; "
                  "must be from linklocal\n", ip6_sprintf(&src6)));
            goto bad;
      }
      if (ip6->ip6_hlim != 255) {
            nd6log((LOG_ERR,
                  "ICMP6 redirect sent from %s rejected; "
                  "hlim=%d (must be 255)\n",
                  ip6_sprintf(&src6), ip6->ip6_hlim));
            goto bad;
      }
    {
      /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
      struct sockaddr_in6 sin6;
      struct in6_addr *gw6;

      bzero(&sin6, sizeof(sin6));
      sin6.sin6_family = AF_INET6;
      sin6.sin6_len = sizeof(struct sockaddr_in6);
      bcopy(&reddst6, &sin6.sin6_addr, sizeof(reddst6));
      rt = rtalloc1((struct sockaddr *)&sin6, 0
#ifdef __FreeBSD__
                  , 0UL
#endif
                  );
      if (rt) {
            if (rt->rt_gateway == NULL ||
                rt->rt_gateway->sa_family != AF_INET6) {
                  nd6log((LOG_ERR,
                      "ICMP6 redirect rejected; no route "
                      "with inet6 gateway found for redirect dst: %s\n",
                      icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
                  RTFREE(rt);
                  goto bad;
            }

            gw6 = &(((struct sockaddr_in6 *)rt->rt_gateway)->sin6_addr);
            if (bcmp(&src6, gw6, sizeof(struct in6_addr)) != 0) {
                  nd6log((LOG_ERR,
                        "ICMP6 redirect rejected; "
                        "not equal to gw-for-src=%s (must be same): "
                        "%s\n",
                        ip6_sprintf(gw6),
                        icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
                  RTFREE(rt);
                  goto bad;
            }
      } else {
            nd6log((LOG_ERR,
                  "ICMP6 redirect rejected; "
                  "no route found for redirect dst: %s\n",
                  icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
            goto bad;
      }
      RTFREE(rt);
      rt = NULL;
    }
      if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
            nd6log((LOG_ERR,
                  "ICMP6 redirect rejected; "
                  "redirect dst must be unicast: %s\n",
                  icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
            goto bad;
      }

      is_router = is_onlink = 0;
      if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
            is_router = 1;    /* router case */
      if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
            is_onlink = 1;    /* on-link destination case */
      if (!is_router && !is_onlink) {
            nd6log((LOG_ERR,
                  "ICMP6 redirect rejected; "
                  "neither router case nor onlink case: %s\n",
                  icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
            goto bad;
      }
      /* validation passed */

      icmp6len -= sizeof(*nd_rd);
      nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
      if (nd6_options(&ndopts) < 0) {
            nd6log((LOG_INFO, "icmp6_redirect_input: "
                  "invalid ND option, rejected: %s\n",
                  icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
            /* nd6_options have incremented stats */
            goto freeit;
      }

      if (ndopts.nd_opts_tgt_lladdr) {
            lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
            lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
      }

      if (ndopts.nd_opts_rh) {
            redirhdrlen = ndopts.nd_opts_rh->nd_opt_rh_len;
            redirhdr = (u_char *)(ndopts.nd_opts_rh + 1); /* xxx */
      }

      if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
            nd6log((LOG_INFO,
                  "icmp6_redirect_input: lladdrlen mismatch for %s "
                  "(if %d, icmp6 packet %d): %s\n",
                  ip6_sprintf(&redtgt6), ifp->if_addrlen, lladdrlen - 2,
                  icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
            goto bad;
      }

      /* RFC 2461 8.3 */
      nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
                   is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);

      if (!is_onlink) { /* better router case.  perform rtredirect. */
            /* perform rtredirect */
            struct sockaddr_in6 sdst;
            struct sockaddr_in6 sgw;
            struct sockaddr_in6 ssrc;
#ifdef __bsdi__
            extern int icmp_redirtimeout; /* XXX */
#endif
#if defined(__NetBSD__) || defined(__OpenBSD__)
            unsigned long rtcount;
            struct rtentry *newrt = NULL;
#endif

#if defined(__NetBSD__) || defined(__OpenBSD__)
            /*
             * do not install redirect route, if the number of entries
             * is too much (> hiwat).  note that, the node (= host) will
             * work just fine even if we do not install redirect route
             * (there will be additional hops, though).
             */
            rtcount = rt_timer_count(icmp6_redirect_timeout_q);
            if (0 <= icmp6_redirect_hiwat && rtcount > icmp6_redirect_hiwat)
                  return;
            else if (0 <= icmp6_redirect_lowat &&
                rtcount > icmp6_redirect_lowat) {
                  /*
                   * XXX nuke a victim, install the new one.
                   */
            }
#endif

            bzero(&sdst, sizeof(sdst));
            bzero(&sgw, sizeof(sgw));
            bzero(&ssrc, sizeof(ssrc));
            sdst.sin6_family = sgw.sin6_family = ssrc.sin6_family = AF_INET6;
            sdst.sin6_len = sgw.sin6_len = ssrc.sin6_len =
                  sizeof(struct sockaddr_in6);
            bcopy(&redtgt6, &sgw.sin6_addr, sizeof(struct in6_addr));
            bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
            bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
            rtredirect((struct sockaddr *)&sdst, (struct sockaddr *)&sgw,
                     (struct sockaddr *)NULL, RTF_GATEWAY | RTF_HOST,
                     (struct sockaddr *)&ssrc,
#ifdef __bsdi__
                     icmp_redirtimeout
#elif defined(__NetBSD__) || defined(__OpenBSD__)
                     &newrt
#else
                     (struct rtentry **)NULL
#endif
                     );

#if defined(__NetBSD__) || defined(__OpenBSD__)
            if (newrt) {
                  (void)rt_timer_add(newrt, icmp6_redirect_timeout,
                      icmp6_redirect_timeout_q);
                  rtfree(newrt);
            }
#endif
      }
      /* finally update cached route in each socket via pfctlinput */
      {
            struct sockaddr_in6 sdst;

            bzero(&sdst, sizeof(sdst));
            sdst.sin6_family = AF_INET6;
            sdst.sin6_len = sizeof(struct sockaddr_in6);
            bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
            pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
#ifdef IPSEC
            key_sa_routechange((struct sockaddr *)&sdst);
#endif
      }

 freeit:
      m_freem(m);
      return;

 bad:
      icmp6stat.icp6s_badredirect++;
      m_freem(m);
}

void
icmp6_redirect_output(m0, rt)
      struct mbuf *m0;
      struct rtentry *rt;
{
      struct ifnet *ifp;      /* my outgoing interface */
      struct in6_addr *ifp_ll6;
      struct in6_addr *router_ll6;
      struct ip6_hdr *sip6;   /* m0 as struct ip6_hdr */
      struct mbuf *m = NULL;  /* newly allocated one */
      struct ip6_hdr *ip6;    /* m as struct ip6_hdr */
      struct nd_redirect *nd_rd;
      size_t maxlen;
      u_char *p;
      struct sockaddr_in6 src_sa;
      int64_t zoneid;

      icmp6_errcount(&icmp6stat.icp6s_outerrhist, ND_REDIRECT, 0);

      /* if we are not router, we don't send icmp6 redirect */
      if (!ip6_forwarding || ip6_accept_rtadv)
            goto fail;

      /* sanity check */
      if (!m0 || !rt || !(rt->rt_flags & RTF_UP) || !(ifp = rt->rt_ifp))
            goto fail;

      /*
       * Address check:
       *  the source address must identify a neighbor, and
       *  the destination address must not be a multicast address
       *  [RFC 2461, sec 8.2]
       */
      sip6 = mtod(m0, struct ip6_hdr *);
      bzero(&src_sa, sizeof(src_sa));
      src_sa.sin6_family = AF_INET6;
      src_sa.sin6_len = sizeof(src_sa);
      src_sa.sin6_addr = sip6->ip6_src;
      /* we don't currently use sin6_scope_id, but eventually use it */
      if ((zoneid = in6_addr2zoneid(ifp, &sip6->ip6_src)) < 0)
            goto fail;
      src_sa.sin6_scope_id = zoneid;
      if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
            goto fail;
      if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
            goto fail;  /* what should we do here? */

      /* rate limit */
      if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
            goto fail;

      /*
       * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
       * we almost always ask for an mbuf cluster for simplicity.
       * (MHLEN < IPV6_MMTU is almost always true)
       */
#if IPV6_MMTU >= MCLBYTES
# error assumption failed about IPV6_MMTU and MCLBYTES
#endif
      MGETHDR(m, M_DONTWAIT, MT_HEADER);
      if (m && IPV6_MMTU >= MHLEN)
            MCLGET(m, M_DONTWAIT);
      if (!m)
            goto fail;
      m->m_pkthdr.rcvif = NULL;
      m->m_len = 0;
      maxlen = M_TRAILINGSPACE(m);
      maxlen = min(IPV6_MMTU, maxlen);
      /* just for safety */
      if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
          ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
            goto fail;
      }

      {
            /* get ip6 linklocal address for ifp(my outgoing interface). */
            struct in6_ifaddr *ia;
            if ((ia = in6ifa_ifpforlinklocal(ifp,
                                     IN6_IFF_NOTREADY|
                                     IN6_IFF_ANYCAST)) == NULL)
                  goto fail;
            ifp_ll6 = &ia->ia_addr.sin6_addr;
      }

      /* get ip6 linklocal address for the router. */
      if (rt->rt_gateway && (rt->rt_flags & RTF_GATEWAY)) {
            struct sockaddr_in6 *sin6;
            sin6 = (struct sockaddr_in6 *)rt->rt_gateway;
            router_ll6 = &sin6->sin6_addr;
            if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
                  router_ll6 = (struct in6_addr *)NULL;
      } else
            router_ll6 = (struct in6_addr *)NULL;

      /* ip6 */
      ip6 = mtod(m, struct ip6_hdr *);
      ip6->ip6_flow = 0;
      ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
      ip6->ip6_vfc |= IPV6_VERSION;
      /* ip6->ip6_plen will be set later */
      ip6->ip6_nxt = IPPROTO_ICMPV6;
      ip6->ip6_hlim = 255;
      /* ip6->ip6_src must be linklocal addr for my outgoing if. */
      bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
      bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));

      /* ND Redirect */
      nd_rd = (struct nd_redirect *)(ip6 + 1);
      nd_rd->nd_rd_type = ND_REDIRECT;
      nd_rd->nd_rd_code = 0;
      nd_rd->nd_rd_reserved = 0;
      if (rt->rt_flags & RTF_GATEWAY) {
            /*
             * nd_rd->nd_rd_target must be a link-local address in
             * better router cases.
             */
            if (!router_ll6)
                  goto fail;
            bcopy(router_ll6, &nd_rd->nd_rd_target,
                  sizeof(nd_rd->nd_rd_target));
            bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
                  sizeof(nd_rd->nd_rd_dst));
      } else {
            /* make sure redtgt == reddst */
            bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
                  sizeof(nd_rd->nd_rd_target));
            bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
                  sizeof(nd_rd->nd_rd_dst));
      }

      p = (u_char *)(nd_rd + 1);

      if (!router_ll6)
            goto nolladdropt;

    {
      /* target lladdr option */
      struct rtentry *rt_router = NULL;
      int len;
      struct sockaddr_dl *sdl;
      struct nd_opt_hdr *nd_opt;
      char *lladdr;

      rt_router = nd6_lookup(router_ll6, 0, ifp);
      if (!rt_router)
            goto nolladdropt;
      len = sizeof(*nd_opt) + ifp->if_addrlen;
      len = (len + 7) & ~7;   /* round by 8 */
      /* safety check */
      if (len + (p - (u_char *)ip6) > maxlen)
            goto nolladdropt;
      if (!(rt_router->rt_flags & RTF_GATEWAY) &&
          (rt_router->rt_flags & RTF_LLINFO) &&
          (rt_router->rt_gateway->sa_family == AF_LINK) &&
          (sdl = (struct sockaddr_dl *)rt_router->rt_gateway) &&
          sdl->sdl_alen) {
            nd_opt = (struct nd_opt_hdr *)p;
            nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
            nd_opt->nd_opt_len = len >> 3;
            lladdr = (char *)(nd_opt + 1);
            bcopy(LLADDR(sdl), lladdr, ifp->if_addrlen);
            p += len;
      }
    }
nolladdropt:;

      m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;

      /* just to be safe */
#ifdef M_DECRYPTED      /* not openbsd */
      if (m0->m_flags & M_DECRYPTED)
            goto noredhdropt;
#endif
      if (p - (u_char *)ip6 > maxlen)
            goto noredhdropt;

    {
      /* redirected header option */
      int len;
      struct nd_opt_rd_hdr *nd_opt_rh;

      /*
       * compute the maximum size for icmp6 redirect header option.
       * XXX room for auth header?
       */
      len = maxlen - (p - (u_char *)ip6);
      len &= ~7;

      /* This is just for simplicity. */
      if (m0->m_pkthdr.len != m0->m_len) {
            if (m0->m_next) {
                  m_freem(m0->m_next);
                  m0->m_next = NULL;
            }
            m0->m_pkthdr.len = m0->m_len;
      }

      /*
       * Redirected header option spec (RFC2461 4.6.3) talks nothing
       * about padding/truncate rule for the original IP packet.
       * From the discussion on IPv6imp in Feb 1999, the consensus was:
       * - "attach as much as possible" is the goal
       * - pad if not aligned (original size can be guessed by original
       *   ip6 header)
       * Following code adds the padding if it is simple enough,
       * and truncates if not.
       */
      if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
            panic("assumption failed in %s:%d\n", __FILE__, __LINE__);

      if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
            /* not enough room, truncate */
            m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
      } else {
            /* enough room, pad or truncate */
            size_t extra;

            extra = m0->m_pkthdr.len % 8;
            if (extra) {
                  /* pad if easy enough, truncate if not */
                  if (8 - extra <= M_TRAILINGSPACE(m0)) {
                        /* pad */
                        m0->m_len += (8 - extra);
                        m0->m_pkthdr.len += (8 - extra);
                  } else {
                        /* truncate */
                        m0->m_pkthdr.len -= extra;
                        m0->m_len -= extra;
                  }
            }
            len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
            m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
      }

      nd_opt_rh = (struct nd_opt_rd_hdr *)p;
      bzero(nd_opt_rh, sizeof(*nd_opt_rh));
      nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
      nd_opt_rh->nd_opt_rh_len = len >> 3;
      p += sizeof(*nd_opt_rh);
      m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;

      /* connect m0 to m */
      m->m_next = m0;
      m->m_pkthdr.len = m->m_len + m0->m_len;
    }
noredhdropt:;

      if (IN6_IS_ADDR_LINKLOCAL(&sip6->ip6_src))
            sip6->ip6_src.s6_addr16[1] = 0;
      if (IN6_IS_ADDR_LINKLOCAL(&sip6->ip6_dst))
            sip6->ip6_dst.s6_addr16[1] = 0;
#if 0
      if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
            ip6->ip6_src.s6_addr16[1] = 0;
      if (IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst))
            ip6->ip6_dst.s6_addr16[1] = 0;
#endif
      if (IN6_IS_ADDR_LINKLOCAL(&nd_rd->nd_rd_target))
            nd_rd->nd_rd_target.s6_addr16[1] = 0;
      if (IN6_IS_ADDR_LINKLOCAL(&nd_rd->nd_rd_dst))
            nd_rd->nd_rd_dst.s6_addr16[1] = 0;

      ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));

      nd_rd->nd_rd_cksum = 0;
      nd_rd->nd_rd_cksum
            = in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), ntohs(ip6->ip6_plen));

      /* send the packet to outside... */
#ifdef IPSEC
      /* Don't lookup socket */
      (void)ipsec_setsocket(m, NULL);
#endif /* IPSEC */
      if (ip6_output(m, NULL, NULL, 0, NULL, NULL) != 0)
            icmp6_ifstat_inc(ifp, ifs6_out_error);

      icmp6_ifstat_inc(ifp, ifs6_out_msg);
      icmp6_ifstat_inc(ifp, ifs6_out_redirect);
      icmp6stat.icp6s_outhist[ND_REDIRECT]++;

      return;

fail:
      if (m)
            m_freem(m);
      if (m0)
            m_freem(m0);
}

#ifdef HAVE_NRL_INPCB
#define sotoin6pcb      sotoinpcb
#define in6pcb          inpcb
#define in6p_icmp6filt  inp_icmp6filt
#endif
/*
 * ICMPv6 socket option processing.
 */
int
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
icmp6_ctloutput(so, sopt)
      struct socket *so;
      struct sockopt *sopt;
#else
icmp6_ctloutput(op, so, level, optname, mp)
      int op;
      struct socket *so;
      int level, optname;
      struct mbuf **mp;
#endif
{
      int error = 0;
      int optlen;
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
      struct inpcb *inp = sotoinpcb(so);
      int level, op, optname;

      if (sopt) {
            level = sopt->sopt_level;
            op = sopt->sopt_dir;
            optname = sopt->sopt_name;
            optlen = sopt->sopt_valsize;
      } else
            level = op = optname = optlen = 0;
#else
      struct in6pcb *in6p = sotoin6pcb(so);
      struct mbuf *m = *mp;

      optlen = m ? m->m_len : 0;
#endif

      if (level != IPPROTO_ICMPV6) {
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
            if (op == PRCO_SETOPT && m)
                  (void)m_free(m);
#endif
            return EINVAL;
      }

      switch (op) {
      case PRCO_SETOPT:
            switch (optname) {
            case ICMP6_FILTER:
                {
                  struct icmp6_filter *p;

                  if (optlen != sizeof(*p)) {
                        error = EMSGSIZE;
                        break;
                  }
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
                  if (inp->in6p_icmp6filt == NULL) {
                        error = EINVAL;
                        break;
                  }
                  error = sooptcopyin(sopt, inp->in6p_icmp6filt, optlen,
                        optlen);
#else
                  p = mtod(m, struct icmp6_filter *);
                  if (!p || !in6p->in6p_icmp6filt) {
                        error = EINVAL;
                        break;
                  }
                  bcopy(p, in6p->in6p_icmp6filt,
                        sizeof(struct icmp6_filter));
                  error = 0;
#endif
                  break;
                }

            default:
                  error = ENOPROTOOPT;
                  break;
            }
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
            if (m)
                  (void)m_freem(m);
#endif            
            break;

      case PRCO_GETOPT:
            switch (optname) {
            case ICMP6_FILTER:
                {
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
                  if (inp->in6p_icmp6filt == NULL) {
                        error = EINVAL;
                        break;
                  }
                  error = sooptcopyout(sopt, inp->in6p_icmp6filt,
                        sizeof(struct icmp6_filter));
#else
                  struct icmp6_filter *p;

                  if (!in6p->in6p_icmp6filt) {
                        error = EINVAL;
                        break;
                  }
                  *mp = m = m_get(M_WAIT, MT_SOOPTS);
                  m->m_len = sizeof(struct icmp6_filter);
                  p = mtod(m, struct icmp6_filter *);
                  bcopy(in6p->in6p_icmp6filt, p,
                        sizeof(struct icmp6_filter));
                  error = 0;
#endif
                  break;
                }

            default:
                  error = ENOPROTOOPT;
                  break;
            }
            break;
      }

      return(error);
}
#ifdef HAVE_NRL_INPCB
#undef sotoin6pcb
#undef in6pcb
#undef in6p_icmp6filt
#endif

#ifndef HAVE_PPSRATECHECK
#ifndef timersub
#define     timersub(tvp, uvp, vvp)                               \
      do {                                            \
            (vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;        \
            (vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;     \
            if ((vvp)->tv_usec < 0) {                       \
                  (vvp)->tv_sec--;                    \
                  (vvp)->tv_usec += 1000000;                \
            }                                         \
      } while (0)
#endif

/*
 * ppsratecheck(): packets (or events) per second limitation.
 */
static int
ppsratecheck(lasttime, curpps, maxpps)
      struct timeval *lasttime;
      int *curpps;
      int maxpps; /* maximum pps allowed */
{
      struct timeval tv, delta;
      int s, rv;

      s = splclock(); 
#ifndef __FreeBSD__
      tv = mono_time;
#else
      microtime(&tv);
#endif
      splx(s);

      timersub(&tv, lasttime, &delta);

      /*
       * Check for 0,0 so that the message will be seen at least once.
       * If more than one second has passed since the last update of
       * lasttime, reset the counter.
       *
       * We do increment *curpps even in *curpps < maxpps case, as some may
       * try to use *curpps for stat purposes as well.
       */
      if ((lasttime->tv_sec == 0 && lasttime->tv_usec == 0) ||
          delta.tv_sec >= 1) {
            *lasttime = tv;
            *curpps = 0;
            rv = 1;
      } else if (maxpps < 0)
            rv = 1;
      else if (*curpps < maxpps)
            rv = 1;
      else
            rv = 0;

#if 1 /* DIAGNOSTIC? */
      /* be careful about wrap-around */
      if (*curpps + 1 > *curpps)
            *curpps = *curpps + 1;
#else
      /*
       * assume that there's not too many calls to this function.
       * not sure if the assumption holds, as it depends on *caller's*
       * behavior, not the behavior of this function.
       * IMHO it is wrong to make assumption on the caller's behavior,
       * so the above #if is #if 1, not #ifdef DIAGNOSTIC.
       */
      *curpps = *curpps + 1;
#endif

      return (rv);
}
#endif

/*
 * Perform rate limit check.
 * Returns 0 if it is okay to send the icmp6 packet.
 * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
 * limitation.
 *
 * XXX per-destination/type check necessary?
 */
static int
icmp6_ratelimit(dst, type, code)
      const struct in6_addr *dst;   /* not used at this moment */
      const int type;               /* not used at this moment */
      const int code;               /* not used at this moment */
{
      int ret;

      ret = 0;    /* okay to send */

      /* PPS limit */
      if (!ppsratecheck(&icmp6errppslim_last, &icmp6errpps_count,
          icmp6errppslim)) {
            /* The packet is subject to rate limit */
            ret++;
      }

      return ret;
}

/*
 * Swap ip6_src and the address in the homeaddress destination option.
 * Since the dest6 processing routine swaps ip6_src and homeaddr (if
 * any), we must swap them again when we send back the ip datagram to
 * the sender (ex. icmp6_error).
 *
 * returns 0 if succeeded.
 */
static int
icmp6_recover_src(m)
      struct mbuf *m; /* original ip6 packet */
{
      int off, nxt, finished = 0;
      struct ip6_hdr *oip6;
      struct ip6_ext *exts;
      struct ip6_dest *dstopts;
      int dstoptlen;
      u_int8_t *opt;
      int optlen;
      struct ip6_opt_home_address *haopt;
      struct in6_addr t;
      int error = 0;

#ifndef PULLDOWN_TEST 
      IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), ENOBUFS);
      oip6 = mtod(m, struct ip6_hdr *);
#else
      IP6_EXTHDR_GET(oip6, struct ip6_hdr *, m, 0, sizeof(*oip6));
      if (oip6 == NULL) {
            error = ENOBUFS;
            goto bad;
      }
#endif

      off = sizeof(struct ip6_hdr);
      nxt = oip6->ip6_nxt;
      while (off + 2 < m->m_pkthdr.len) {
            switch (nxt) {
            case IPPROTO_DSTOPTS:
#ifndef PULLDOWN_TEST 
                  IP6_EXTHDR_CHECK(m, off, sizeof(struct ip6_dest),
                               ENOBUFS);
                  dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);
#else
                  IP6_EXTHDR_GET(dstopts, struct ip6_dest *,
                               m, off, sizeof(*dstopts));
                  if (dstopts == NULL) {
                        error = ENOBUFS;
                        goto bad;
                  }
#endif

                  dstoptlen = (dstopts->ip6d_len + 1) << 3;
#ifndef PULLDOWN_TEST 
                  IP6_EXTHDR_CHECK(m, off, dstoptlen, ENOBUFS);
                  dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);
#else
                  IP6_EXTHDR_GET(dstopts, struct ip6_dest *,
                               m, off, dstoptlen);
                  if (dstopts == NULL) {
                        error = ENOBUFS;
                        goto bad;
                  }
#endif
                  off += dstoptlen;
                  nxt = dstopts->ip6d_nxt;

                  /* find homeaddress dstopt */
                  dstoptlen -= sizeof(struct ip6_dest);
                  opt = (u_int8_t *)dstopts + sizeof(struct ip6_dest);
                  for (optlen = 0; (dstoptlen > 0 && finished == 0);
                       dstoptlen -= optlen, opt += optlen) {
                        if ((*opt != IP6OPT_PAD1) &&
                            (dstoptlen < IP6OPT_MINLEN || *(opt + 1) + 2 > dstoptlen)) {
                              error = EINVAL;
                              goto bad;
                        }
                        switch (*opt) {
                        case IP6OPT_PAD1:
                              optlen = 1;
                              break;
                        case IP6OPT_PADN:
                              optlen = *(opt + 1) + 2;
                              break;
                        case IP6OPT_HOME_ADDRESS:
                              haopt = (struct ip6_opt_home_address *)opt;
                              optlen = haopt->ip6oh_len + 2;
                              if (optlen < sizeof(*haopt)) {
                                    error = EINVAL;
                                    goto bad;
                              }

                              /* swap */
                              bcopy(haopt->ip6oh_addr, &t,
                                    sizeof(haopt->ip6oh_addr));
                              bcopy(&oip6->ip6_src,
                                    haopt->ip6oh_addr,
                                    sizeof(oip6->ip6_src));
                              bcopy(&t, &oip6->ip6_src,
                                    sizeof(t));
                              finished = 1;
                              break;
                        default:
                              optlen = ip6_unknown_opt(opt, m,
                                  opt - mtod(m, u_int8_t *));
                              if (optlen == -1) {
                                    error = EINVAL;
                                    goto bad;
                              }
                              optlen += 2;
                              break;
                        }
                  }
                  break;

            default:
#ifndef PULLDOWN_TEST 
                  IP6_EXTHDR_CHECK(m, off, sizeof(struct ip6_ext),
                               ENOBUFS);
                  exts = (struct ip6_ext *)(mtod(m, caddr_t) + off);
#else
                  IP6_EXTHDR_GET(exts, struct ip6_ext *,
                               m, off, sizeof(*exts));
                  if (exts == NULL) {
                        error = ENOBUFS;
                        goto bad;
                  }
#endif
                  if (nxt == IPPROTO_AH)
                        off += (exts->ip6e_len + 2) << 2;
                  else
                        off += (exts->ip6e_len + 1) << 3;
                  nxt = exts->ip6e_nxt;
                  break;
            }
            if (finished)
                  break;
      }

      return (0);
 bad:
      ip6_delaux(m);
      m_freem(m);
      return (error);
}

#if defined(__NetBSD__) || defined(__OpenBSD__)
static struct rtentry *
icmp6_mtudisc_clone(dst)
      struct sockaddr *dst;
{
      struct rtentry *rt;
      int    error;

      rt = rtalloc1(dst, 1);
      if (rt == 0)
            return NULL;

      /* If we didn't get a host route, allocate one */
      if ((rt->rt_flags & RTF_HOST) == 0) {
            struct rtentry *nrt;

            error = rtrequest((int) RTM_ADD, dst,
                (struct sockaddr *) rt->rt_gateway,
                (struct sockaddr *) 0,
                RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt);
            if (error) {
                  rtfree(rt);
                  return NULL;
            }
            nrt->rt_rmx = rt->rt_rmx;
            rtfree(rt);
            rt = nrt;
      }
      error = rt_timer_add(rt, icmp6_mtudisc_timeout,
                  icmp6_mtudisc_timeout_q);
      if (error) {
            rtfree(rt);
            return NULL;
      }

      return rt;  /* caller need to call rtfree() */
}

static void
icmp6_mtudisc_timeout(rt, r)
      struct rtentry *rt;
      struct rttimer *r;
{
      if (rt == NULL)
            panic("icmp6_mtudisc_timeout: bad route to timeout");
      if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
          (RTF_DYNAMIC | RTF_HOST)) {
            rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
                rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
      } else {
            if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
                  rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
      }
}

static void
icmp6_redirect_timeout(rt, r)
      struct rtentry *rt;
      struct rttimer *r;
{
      if (rt == NULL)
            panic("icmp6_redirect_timeout: bad route to timeout");
      if ((rt->rt_flags & (RTF_GATEWAY | RTF_DYNAMIC | RTF_HOST)) ==
          (RTF_GATEWAY | RTF_DYNAMIC | RTF_HOST)) {
            rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
                rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
      }
}
#endif /* __NetBSD__ || __OpenBSD__ */

#ifdef __bsdi__
void
icmp6_mtuexpire(rt, rtt)
      struct rtentry *rt;
      struct rttimer *rtt;
{
      rt->rt_flags |= RTF_PROBEMTU;
      Free(rtt);
}

int *icmp6_sysvars[] = ICMPV6CTL_VARS;

int
icmp6_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
      int *name;
      u_int namelen;
      void *oldp;
      size_t *oldlenp;
      void *newp;
      size_t newlen;
{
      if (name[0] >= ICMPV6CTL_MAXID)
            return (EOPNOTSUPP);
      switch (name[0]) {
#if 0
      ICMPV6CTL_ND6_PRUNE:
      ICMPV6CTL_ND6_DELAY:
      ICMPV6CTL_ND6_UMAXTRIES:
      ICMPV6CTL_ND6_MMAXTRIES:
      ICMPV6CTL_ND6_USELOOPBACK:
            /* need to check the value. */
#endif
      case ICMPV6CTL_STATS:
            return sysctl_rdtrunc(oldp, oldlenp, newp, &icmp6stat,
                sizeof(icmp6stat));
      case ICMPV6CTL_ND6_DRLIST:
      case ICMPV6CTL_ND6_PRLIST:
            return nd6_sysctl(name[0], oldp, oldlenp, newp, newlen);
      default:
            return (sysctl_int_arr(icmp6_sysvars, name, namelen,
                oldp, oldlenp, newp, newlen));
      }
}
#endif /* __bsdi__ */

#if defined(__NetBSD__) || defined(__OpenBSD__)
#include <vm/vm.h>
#include <sys/sysctl.h>
int
icmp6_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
      int *name;
      u_int namelen;
      void *oldp;
      size_t *oldlenp;
      void *newp;
      size_t newlen;
{

      /* All sysctl names at this level are terminal. */
      if (namelen != 1)
            return ENOTDIR;

      switch (name[0]) {

      case ICMPV6CTL_REDIRACCEPT:
            return sysctl_int(oldp, oldlenp, newp, newlen,
                        &icmp6_rediraccept);
      case ICMPV6CTL_REDIRTIMEOUT:
            return sysctl_int(oldp, oldlenp, newp, newlen,
                        &icmp6_redirtimeout);
      case ICMPV6CTL_STATS:
            return sysctl_rdstruct(oldp, oldlenp, newp,
                        &icmp6stat, sizeof(icmp6stat));
      case ICMPV6CTL_ND6_PRUNE:
            return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_prune);
      case ICMPV6CTL_ND6_DELAY:
            return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_delay);
      case ICMPV6CTL_ND6_UMAXTRIES:
            return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_umaxtries);
      case ICMPV6CTL_ND6_MMAXTRIES:
            return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_mmaxtries);
      case ICMPV6CTL_ND6_USELOOPBACK:
            return sysctl_int(oldp, oldlenp, newp, newlen,
                        &nd6_useloopback);
      case ICMPV6CTL_NODEINFO:
            return sysctl_int(oldp, oldlenp, newp, newlen, &icmp6_nodeinfo);
      case ICMPV6CTL_ERRPPSLIMIT:
            return sysctl_int(oldp, oldlenp, newp, newlen, &icmp6errppslim);
      case ICMPV6CTL_ND6_MAXNUDHINT:
            return sysctl_int(oldp, oldlenp, newp, newlen,
                        &nd6_maxnudhint);
      case ICMPV6CTL_MTUDISC_HIWAT:
            return sysctl_int(oldp, oldlenp, newp, newlen,
                        &icmp6_mtudisc_hiwat);
      case ICMPV6CTL_MTUDISC_LOWAT:
            return sysctl_int(oldp, oldlenp, newp, newlen,
                        &icmp6_mtudisc_lowat);
      case ICMPV6CTL_ND6_DEBUG:
            return sysctl_int(oldp, oldlenp, newp, newlen, &nd6_debug);
      case ICMPV6CTL_ND6_DRLIST:
      case ICMPV6CTL_ND6_PRLIST:
            return nd6_sysctl(name[0], oldp, oldlenp, newp, newlen);
      default:
            return ENOPROTOOPT;
      }
      /* NOTREACHED */
}
#endif /* __NetBSD__ */

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