text: /*-
   * SPDX-License-Identifier: BSD-3-Clause
   *
   * 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.
   *
   *	$KAME: icmp6.c,v 1.211 2001/04/04 05:56:20 itojun Exp $
   */
  
  /*-
   * 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. 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/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #define	MBUF_PRIVATE	/* XXXRW: Optimisation tries to avoid M_EXT mbufs */
  
  #include "opt_inet.h"
  #include "opt_inet6.h"
  
  #include <sys/param.h>
  #include <sys/domain.h>
  #include <sys/jail.h>
  #include <sys/kernel.h>
  #include <sys/lock.h>
  #include <sys/malloc.h>
  #include <sys/mbuf.h>
  #include <sys/proc.h>
  #include <sys/protosw.h>
  #include <sys/signalvar.h>
  #include <sys/socket.h>
  #include <sys/socketvar.h>
  #include <sys/sx.h>
  #include <sys/syslog.h>
  #include <sys/systm.h>
  #include <sys/time.h>
  
  #include <net/if.h>
  #include <net/if_var.h>
  #include <net/if_dl.h>
  #include <net/if_llatbl.h>
  #include <net/if_types.h>
  #include <net/route.h>
  #include <net/vnet.h>
  
  #include <netinet/in.h>
  #include <netinet/in_pcb.h>
  #include <netinet/in_var.h>
  #include <netinet/ip6.h>
  #include <netinet/icmp6.h>
  #include <netinet/tcp_var.h>
  
  #include <netinet6/in6_fib.h>
  #include <netinet6/in6_ifattach.h>
  #include <netinet6/in6_pcb.h>
  #include <netinet6/ip6protosw.h>
  #include <netinet6/ip6_var.h>
  #include <netinet6/scope6_var.h>
  #include <netinet6/mld6_var.h>
  #include <netinet6/nd6.h>
  #include <netinet6/send.h>
  
  extern struct domain inet6domain;
  
  VNET_PCPUSTAT_DEFINE(struct icmp6stat, icmp6stat);
  VNET_PCPUSTAT_SYSINIT(icmp6stat);
  
  #ifdef VIMAGE
  VNET_PCPUSTAT_SYSUNINIT(icmp6stat);
  #endif /* VIMAGE */
  
  VNET_DECLARE(struct inpcbinfo, ripcbinfo);
  VNET_DECLARE(struct inpcbhead, ripcb);
  VNET_DECLARE(int, icmp6errppslim);
  VNET_DEFINE_STATIC(int, icmp6errpps_count) = 0;
  VNET_DEFINE_STATIC(struct timeval, icmp6errppslim_last);
  VNET_DECLARE(int, icmp6_nodeinfo);
  
  #define	V_ripcbinfo			VNET(ripcbinfo)
  #define	V_ripcb				VNET(ripcb)
  #define	V_icmp6errppslim		VNET(icmp6errppslim)
  #define	V_icmp6errpps_count		VNET(icmp6errpps_count)
  #define	V_icmp6errppslim_last		VNET(icmp6errppslim_last)
  #define	V_icmp6_nodeinfo		VNET(icmp6_nodeinfo)
  
  static void icmp6_errcount(int, int);
  static int icmp6_rip6_input(struct mbuf **, int);
  static void icmp6_reflect(struct mbuf *, size_t);
  static int icmp6_ratelimit(const struct in6_addr *, const int, const int);
  static const char *icmp6_redirect_diag(struct in6_addr *,
  	struct in6_addr *, struct in6_addr *);
  static struct mbuf *ni6_input(struct mbuf *, int, struct prison *);
  static struct mbuf *ni6_nametodns(const char *, int, int);
  static int ni6_dnsmatch(const char *, int, const char *, int);
  static int ni6_addrs(struct icmp6_nodeinfo *, struct mbuf *,
  			  struct ifnet **, struct in6_addr *);
  static int ni6_store_addrs(struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
  				struct ifnet *, int);
  static int icmp6_notify_error(struct mbuf **, int, int, int);
  
  /*
   * Kernel module interface for updating icmp6stat.  The argument is an index
   * into icmp6stat treated as an array of u_quad_t.  While this encodes the
   * general layout of icmp6stat into the caller, it doesn't encode its
   * location, so that future changes to add, for example, per-CPU stats
   * support won't cause binary compatibility problems for kernel modules.
   */
  void
  kmod_icmp6stat_inc(int statnum)
  {
  
  	counter_u64_add(VNET(icmp6stat)[statnum], 1);
  }
  
  static void
  icmp6_errcount(int type, int code)
  {
  	switch (type) {
  	case ICMP6_DST_UNREACH:
  		switch (code) {
  		case ICMP6_DST_UNREACH_NOROUTE:
  			ICMP6STAT_INC(icp6s_odst_unreach_noroute);
  			return;
  		case ICMP6_DST_UNREACH_ADMIN:
  			ICMP6STAT_INC(icp6s_odst_unreach_admin);
  			return;
  		case ICMP6_DST_UNREACH_BEYONDSCOPE:
  			ICMP6STAT_INC(icp6s_odst_unreach_beyondscope);
  			return;
  		case ICMP6_DST_UNREACH_ADDR:
  			ICMP6STAT_INC(icp6s_odst_unreach_addr);
  			return;
  		case ICMP6_DST_UNREACH_NOPORT:
  			ICMP6STAT_INC(icp6s_odst_unreach_noport);
  			return;
  		}
  		break;
  	case ICMP6_PACKET_TOO_BIG:
  		ICMP6STAT_INC(icp6s_opacket_too_big);
  		return;
  	case ICMP6_TIME_EXCEEDED:
  		switch (code) {
  		case ICMP6_TIME_EXCEED_TRANSIT:
  			ICMP6STAT_INC(icp6s_otime_exceed_transit);
  			return;
  		case ICMP6_TIME_EXCEED_REASSEMBLY:
  			ICMP6STAT_INC(icp6s_otime_exceed_reassembly);
  			return;
  		}
  		break;
  	case ICMP6_PARAM_PROB:
  		switch (code) {
  		case ICMP6_PARAMPROB_HEADER:
  			ICMP6STAT_INC(icp6s_oparamprob_header);
  			return;
  		case ICMP6_PARAMPROB_NEXTHEADER:
  			ICMP6STAT_INC(icp6s_oparamprob_nextheader);
  			return;
  		case ICMP6_PARAMPROB_OPTION:
  			ICMP6STAT_INC(icp6s_oparamprob_option);
  			return;
  		}
  		break;
  	case ND_REDIRECT:
  		ICMP6STAT_INC(icp6s_oredirect);
  		return;
  	}
  	ICMP6STAT_INC(icp6s_ounknown);
  }
  
  /*
   * A wrapper function for icmp6_error() necessary when the erroneous packet
   * may not contain enough scope zone information.
   */
  void
  icmp6_error2(struct mbuf *m, int type, int code, int param,
      struct ifnet *ifp)
  {
  	struct ip6_hdr *ip6;
  
  	if (ifp == NULL)
  		return;
  
  	if (m->m_len < sizeof(struct ip6_hdr)) {
  		m = m_pullup(m, sizeof(struct ip6_hdr));
  		if (m == NULL) {
  			IP6STAT_INC(ip6s_exthdrtoolong);
  			return;
  		}
  	}
  	ip6 = mtod(m, struct ip6_hdr *);
  
  	if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
  		return;
  	if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
  		return;
  
  	icmp6_error(m, type, code, param);
  }
  
  /*
   * Generate an error packet of type error in response to bad IP6 packet.
   */
  void
  icmp6_error(struct mbuf *m, int type, int code, int param)
  {
  	struct ip6_hdr *oip6, *nip6;
  	struct icmp6_hdr *icmp6;
  	u_int preplen;
  	int off;
  	int nxt;
  
  	ICMP6STAT_INC(icp6s_error);
  
  	/* count per-type-code statistics */
  	icmp6_errcount(type, code);
  
  #ifdef M_DECRYPTED	/*not openbsd*/
  	if (m->m_flags & M_DECRYPTED) {
  		ICMP6STAT_INC(icp6s_canterror);
  		goto freeit;
  	}
  #endif
  
  	if (m->m_len < sizeof(struct ip6_hdr)) {
  		m = m_pullup(m, sizeof(struct ip6_hdr));
  		if (m == NULL) {
  			IP6STAT_INC(ip6s_exthdrtoolong);
  			return;
  		}
  	}
  	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 Packet 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;
  
  		if (m->m_len < off + sizeof(struct icmp6_hdr)) {
  			m = m_pullup(m, off + sizeof(struct icmp6_hdr));
  			if (m == NULL) {
  				IP6STAT_INC(ip6s_exthdrtoolong);
  				return;
  			}
  		}
  		oip6 = mtod(m, struct ip6_hdr *);
  		icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
  
  		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_INC(icp6s_canterror);
  			goto freeit;
  		} else {
  			/* ICMPv6 informational - send the error */
  		}
  	} else {
  		/* non-ICMPv6 - send the error */
  	}
  
  	/* Finally, do rate limitation check. */
  	if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
  		ICMP6STAT_INC(icp6s_toofreq);
  		goto freeit;
  	}
  
  	/*
  	 * OK, ICMP6 can be generated.
  	 */
  
  	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_NOWAIT);	/* FIB is also copied over. */
  	if (m == NULL) {
  		nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
  		return;
  	}
  
  	nip6 = mtod(m, struct ip6_hdr *);
  	nip6->ip6_src  = oip6->ip6_src;
  	nip6->ip6_dst  = oip6->ip6_dst;
  
  	in6_clearscope(&oip6->ip6_src);
  	in6_clearscope(&oip6->ip6_dst);
  
  	icmp6 = (struct icmp6_hdr *)(nip6 + 1);
  	icmp6->icmp6_type = type;
  	icmp6->icmp6_code = code;
  	icmp6->icmp6_pptr = htonl((u_int32_t)param);
  
  	ICMP6STAT_INC(icp6s_outhist[type]);
  	icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
  
  	return;
  
    freeit:
  	/*
  	 * If we can't tell whether or not we can generate ICMP6, free it.
  	 */
  	m_freem(m);
  }
  
  /*
   * Process a received ICMP6 message.
   */
  int
  icmp6_input(struct mbuf **mp, int *offp, int proto)
  {
  	struct mbuf *m, *n;
  	struct ifnet *ifp;
  	struct ip6_hdr *ip6, *nip6;
  	struct icmp6_hdr *icmp6, *nicmp6;
  	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  	int code, error, icmp6len, ip6len, noff, off, sum;
  
  	m = *mp;
  	off = *offp;
  
  	if (m->m_len < off + sizeof(struct icmp6_hdr)) {
  		m = m_pullup(m, off + sizeof(struct icmp6_hdr));
  		if (m == NULL) {
  			IP6STAT_INC(ip6s_exthdrtoolong);
  			*mp = m;
  			return (IPPROTO_DONE);
  		}
  	}
  
  	/*
  	 * Locate icmp6 structure in mbuf, and check
  	 * that not corrupted and of at least minimum length
  	 */
  
  	icmp6len = m->m_pkthdr.len - off;
  	if (icmp6len < sizeof(struct icmp6_hdr)) {
  		ICMP6STAT_INC(icp6s_tooshort);
  		goto freeit;
  	}
  
  	ip6 = mtod(m, struct ip6_hdr *);
  	ifp = m->m_pkthdr.rcvif;
  	/*
  	 * Check multicast group membership.
  	 * Note: SSM filters are not applied for ICMPv6 traffic.
  	 */
  	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  		struct in6_multi	*inm;
  
  		inm = in6m_lookup(ifp, &ip6->ip6_dst);
  		if (inm == NULL) {
  			IP6STAT_INC(ip6s_notmember);
  			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  			goto freeit;
  		}
  	}
  
  	/* Calculate the checksum. */
  	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
  	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(ip6bufs, &ip6->ip6_src)));
  		ICMP6STAT_INC(icp6s_checksum);
  		goto freeit;
  	}
  
  	ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
  	icmp6_ifstat_inc(ifp, ifs6_in_msg);
  	if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
  		icmp6_ifstat_inc(ifp, ifs6_in_error);
  
  	ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
  	switch (icmp6->icmp6_type) {
  	case ICMP6_DST_UNREACH:
  		icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
  		switch (code) {
  		case ICMP6_DST_UNREACH_NOROUTE:
  		case ICMP6_DST_UNREACH_ADDR:	/* PRC_HOSTDEAD is a DOS */
  			code = PRC_UNREACH_NET;
  			break;
  		case ICMP6_DST_UNREACH_ADMIN:
  			icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
  			code = PRC_UNREACH_ADMIN_PROHIB;
  			break;
  		case ICMP6_DST_UNREACH_BEYONDSCOPE:
  			/* I mean "source address was incorrect." */
  			code = PRC_PARAMPROB;
  			break;
  		case ICMP6_DST_UNREACH_NOPORT:
  			code = PRC_UNREACH_PORT;
  			break;
  		default:
  			goto badcode;
  		}
  		goto deliver;
  		break;
  
  	case ICMP6_PACKET_TOO_BIG:
  		icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
  
  		/* validation is made in icmp6_mtudisc_update */
  
  		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(ifp, 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(ifp, ifs6_in_paramprob);
  		switch (code) {
  		case ICMP6_PARAMPROB_NEXTHEADER:
  			code = PRC_UNREACH_PROTOCOL;
  			break;
  		case ICMP6_PARAMPROB_HEADER:
  		case ICMP6_PARAMPROB_OPTION:
  			code = PRC_PARAMPROB;
  			break;
  		default:
  			goto badcode;
  		}
  		goto deliver;
  		break;
  
  	case ICMP6_ECHO_REQUEST:
  		icmp6_ifstat_inc(ifp, ifs6_in_echo);
  		if (code != 0)
  			goto badcode;
  		if ((n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) == NULL) {
  			/* Give up remote */
  			break;
  		}
  		if (!M_WRITABLE(n)
  		 || n->m_len < off + sizeof(struct icmp6_hdr)) {
  			struct mbuf *n0 = n;
  			int n0len;
  
  			CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) <= MHLEN);
  			n = m_gethdr(M_NOWAIT, n0->m_type);
  			if (n == NULL) {
  				/* Give up remote */
  				m_freem(n0);
  				break;
  			}
  
  			m_move_pkthdr(n, n0);	/* FIB copied. */
  			n0len = n0->m_pkthdr.len;	/* save for use below */
  			/*
  			 * 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);
  			/* new mbuf contains only ipv6+icmpv6 headers */
  			n->m_len = noff + sizeof(struct icmp6_hdr);
  			/*
  			 * Adjust mbuf.  ip6_plen will be adjusted in
  			 * ip6_output().
  			 */
  			m_adj(n0, off + sizeof(struct icmp6_hdr));
  			/* recalculate complete packet size */
  			n->m_pkthdr.len = n0len + (noff - off);
  			n->m_next = n0;
  		} else {
  			if (n->m_len < off + sizeof(*nicmp6)) {
  				n = m_pullup(n, off + sizeof(*nicmp6));
  				if (n == NULL) {
  					IP6STAT_INC(ip6s_exthdrtoolong);
  					break;
  				}
  			}
  			nicmp6 = (struct icmp6_hdr *)(mtod(n, caddr_t) + off);
  			noff = off;
  		}
  		if (n) {
  			nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
  			nicmp6->icmp6_code = 0;
  			ICMP6STAT_INC(icp6s_reflect);
  			ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
  			icmp6_reflect(n, noff);
  		}
  		break;
  
  	case ICMP6_ECHO_REPLY:
  		icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
  		if (code != 0)
  			goto badcode;
  		break;
  
  	case MLD_LISTENER_QUERY:
  	case MLD_LISTENER_REPORT:
  	case MLD_LISTENER_DONE:
  	case MLDV2_LISTENER_REPORT:
  		/*
  		 * Drop MLD traffic which is not link-local, has a hop limit
  		 * of greater than 1 hop, or which does not have the
  		 * IPv6 HBH Router Alert option.
  		 * As IPv6 HBH options are stripped in ip6_input() we must
  		 * check an mbuf header flag.
  		 * XXX Should we also sanity check that these messages
  		 * were directed to a link-local multicast prefix?
  		 */
  		if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
  			goto freeit;
  		if (mld_input(&m, off, icmp6len) != 0) {
  			*mp = NULL;
  			return (IPPROTO_DONE);
  		}
  		/* m stays. */
  		break;
  
  	case ICMP6_WRUREQUEST:	/* ICMP6_FQDN_QUERY */
  	    {
  		enum { WRU, FQDN } mode;
  		struct prison *pr;
  
  		if (!V_icmp6_nodeinfo)
  			break;
  
  		if (icmp6len == sizeof(struct icmp6_hdr) + 4)
  			mode = WRU;
  		else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
  			mode = FQDN;
  		else
  			goto badlen;
  
  		pr = NULL;
  		sx_slock(&allprison_lock);
  		TAILQ_FOREACH(pr, &allprison, pr_list)
  			if (pr->pr_vnet == ifp->if_vnet)
  				break; 
  		sx_sunlock(&allprison_lock);
  		if (pr == NULL)
  			pr = curthread->td_ucred->cr_prison;
  		if (mode == FQDN) {
  			if (m->m_len < off + sizeof(struct icmp6_nodeinfo)) {
  				m = m_pullup(m, off +
  				    sizeof(struct icmp6_nodeinfo));
  				if (m == NULL) {
  					IP6STAT_INC(ip6s_exthdrtoolong);
  					*mp = m;
  					return (IPPROTO_DONE);
  				}
  			}
  			n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
  			if (n)
  				n = ni6_input(n, off, pr);
  			/* XXX meaningless if n == NULL */
  			noff = sizeof(struct ip6_hdr);
  		} else {
  			u_char *p;
  			int maxhlen, hlen;
  
  			/*
  			 * XXX: this combination of flags is pointless,
  			 * but should we keep this for compatibility?
  			 */
  			if ((V_icmp6_nodeinfo & (ICMP6_NODEINFO_FQDNOK |
  			    ICMP6_NODEINFO_TMPADDROK)) !=
  			    (ICMP6_NODEINFO_FQDNOK | ICMP6_NODEINFO_TMPADDROK))
  				break;
  
  			if (code != 0)
  				goto badcode;
  
  			CTASSERT(sizeof(*nip6) + sizeof(*nicmp6) + 4 <= MHLEN);
  			n = m_gethdr(M_NOWAIT, m->m_type);
  			if (n == NULL) {
  				/* Give up remote */
  				break;
  			}
  			if (!m_dup_pkthdr(n, m, M_NOWAIT)) {
  				/*
  				 * Previous code did a blind M_COPY_PKTHDR
  				 * and said "just for rcvif".  If true, then
  				 * we could tolerate the dup failing (due to
  				 * the deep copy of the tag chain).  For now
  				 * be conservative and just fail.
  				 */
  				m_free(n);
  				n = NULL;
  				break;
  			}
  			/*
  			 * 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);
  
  			maxhlen = M_TRAILINGSPACE(n) -
  			    (sizeof(*nip6) + sizeof(*nicmp6) + 4);
  			mtx_lock(&pr->pr_mtx);
  			hlen = strlen(pr->pr_hostname);
  			if (maxhlen > hlen)
  				maxhlen = hlen;
  			/* meaningless TTL */
  			bcopy(pr->pr_hostname, p + 4, maxhlen);
  			mtx_unlock(&pr->pr_mtx);
  			noff = sizeof(struct ip6_hdr);
  			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;
  		}
  		if (n) {
  			ICMP6STAT_INC(icp6s_reflect);
  			ICMP6STAT_INC(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(ifp, ifs6_in_routersolicit);
  		if (code != 0)
  			goto badcode;
  		if (icmp6len < sizeof(struct nd_router_solicit))
  			goto badlen;
  		if (send_sendso_input_hook != NULL) {
  			if (m->m_len < off + icmp6len) {
  				m = m_pullup(m, off + icmp6len);
  				if (m == NULL) {
  					IP6STAT_INC(ip6s_exthdrtoolong);
  					*mp = NULL;
  					return (IPPROTO_DONE);
  				}
  			}
  			error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
  			if (error == 0) {
  				m = NULL;
  				goto freeit;
  			}
  		}
  		n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
  		nd6_rs_input(m, off, icmp6len);
  		m = n;
  		if (m == NULL)
  			goto freeit;
  		break;
  
  	case ND_ROUTER_ADVERT:
  		icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
  		if (code != 0)
  			goto badcode;
  		if (icmp6len < sizeof(struct nd_router_advert))
  			goto badlen;
  		if (send_sendso_input_hook != NULL) {
  			error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
  			if (error == 0) {
  				m = NULL;
  				goto freeit;
  			}
  		}
  		n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
  		nd6_ra_input(m, off, icmp6len);
  		m = n;
  		if (m == NULL)
  			goto freeit;
  		break;
  
  	case ND_NEIGHBOR_SOLICIT:
  		icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
  		if (code != 0)
  			goto badcode;
  		if (icmp6len < sizeof(struct nd_neighbor_solicit))
  			goto badlen;
  		if (send_sendso_input_hook != NULL) {
  			error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
  			if (error == 0) {
  				m = NULL;
  				goto freeit;
  			}
  		}
  		n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
  		nd6_ns_input(m, off, icmp6len);
  		m = n;
  		if (m == NULL)
  			goto freeit;
  		break;
  
  	case ND_NEIGHBOR_ADVERT:
  		icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
  		if (code != 0)
  			goto badcode;
  		if (icmp6len < sizeof(struct nd_neighbor_advert))
  			goto badlen;
  		if (send_sendso_input_hook != NULL) {
  			error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
  			if (error == 0) {
  				m = NULL;
  				goto freeit;
  			}
  		}
  		n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
  		nd6_na_input(m, off, icmp6len);
  		m = n;
  		if (m == NULL)
  			goto freeit;
  		break;
  
  	case ND_REDIRECT:
  		icmp6_ifstat_inc(ifp, ifs6_in_redirect);
  		if (code != 0)
  			goto badcode;
  		if (icmp6len < sizeof(struct nd_redirect))
  			goto badlen;
  		if (send_sendso_input_hook != NULL) {
  			error = send_sendso_input_hook(m, ifp, SND_IN, ip6len);
  			if (error == 0) {
  				m = NULL;
  				goto freeit;
  			}
  		}
  		n = m_copym(m, 0, M_COPYALL, M_NOWAIT);
  		icmp6_redirect_input(m, off);
  		m = n;
  		if (m == NULL)
  			goto freeit;
  		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(ip6bufs, &ip6->ip6_src),
  		    ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  		    ifp ? ifp->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) != 0) {
  			/* In this case, m should've been freed. */
  			*mp = NULL;
  			return (IPPROTO_DONE);
  		}
  		break;
  
  	badcode:
  		ICMP6STAT_INC(icp6s_badcode);
  		break;
  
  	badlen:
  		ICMP6STAT_INC(icp6s_badlen);
  		break;
  	}
  
  	/* deliver the packet to appropriate sockets */
  	icmp6_rip6_input(&m, *offp);
  
  	*mp = m;
  	return (IPPROTO_DONE);
  
   freeit:
  	m_freem(m);
  	*mp = NULL;
  	return (IPPROTO_DONE);
  }
  
  static int
  icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
  {
  	struct mbuf *m;
  	struct icmp6_hdr *icmp6;
  	struct ip6_hdr *eip6;
  	u_int32_t notifymtu;
  	struct sockaddr_in6 icmp6src, icmp6dst;
  
  	m = *mp;
  
  	if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
  		ICMP6STAT_INC(icp6s_tooshort);
  		goto freeit;
  	}
  
  	if (m->m_len < off + sizeof(*icmp6) + sizeof(struct ip6_hdr)) {
  		m = m_pullup(m, off + sizeof(*icmp6) + sizeof(struct ip6_hdr));
  		if (m == NULL) {
  			IP6STAT_INC(ip6s_exthdrtoolong);
  			*mp = m;
  			return (-1);
  		}
  	}
  	icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
  	eip6 = (struct ip6_hdr *)(icmp6 + 1);
  
  	/* Detect the upper level protocol */
  	{
  		void (*ctlfunc)(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:
  				if (m->m_len < eoff + sizeof(struct ip6_ext)) {
  					m = m_pullup(m, eoff +
  					    sizeof(struct ip6_ext));
  					if (m == NULL) {
  						IP6STAT_INC(ip6s_exthdrtoolong);
  						*mp = m;
  						return (-1);
  					}
  				}
  				eh = (struct ip6_ext *)
  				    (mtod(m, caddr_t) + eoff);
  				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).
  				 */
  				if (m->m_len < eoff + sizeof(*rth)) {
  					m = m_pullup(m, eoff + sizeof(*rth));
  					if (m == NULL) {
  						IP6STAT_INC(ip6s_exthdrtoolong);
  						*mp = m;
  						return (-1);
  					}
  				}
  				rth = (struct ip6_rthdr *)
  				    (mtod(m, caddr_t) + eoff);
  				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;
  
  					if (m->m_len < eoff + rthlen) {
  						m = m_pullup(m, eoff + rthlen);
  						if (m == NULL) {
  							IP6STAT_INC(
  							    ip6s_exthdrtoolong);
  							*mp = m;
  							return (-1);
  						}
  					}
  					rth0 = (struct ip6_rthdr0 *)
  					    (mtod(m, caddr_t) + eoff);
  					/* 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:
  				if (m->m_len < eoff + sizeof(struct ip6_frag)) {
  					m = m_pullup(m, eoff +
  					    sizeof(struct ip6_frag));
  					if (m == NULL) {
  						IP6STAT_INC(ip6s_exthdrtoolong);
  						*mp = m;
  						return (-1);
  					}
  				}
  				fh = (struct ip6_frag *)(mtod(m, caddr_t) +
  				    eoff);
  				/*
  				 * 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:
  		icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
  
  		/*
  		 * retrieve parameters from the inner IPv6 header, and convert
  		 * them into sockaddr structures.
  		 * XXX: there is no guarantee that the source or destination
  		 * addresses of the inner packet are in the same scope as
  		 * the addresses of the icmp packet.  But there is no other
  		 * way to determine the zone.
  		 */
  		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 (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
  			goto freeit;
  		bzero(&icmp6src, sizeof(icmp6src));
  		icmp6src.sin6_len = sizeof(struct sockaddr_in6);
  		icmp6src.sin6_family = AF_INET6;
  		icmp6src.sin6_addr = eip6->ip6_src;
  		if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
  			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;
  			icmp6_mtudisc_update(&ip6cp, 1);	/*XXX*/
  		}
  
  		ctlfunc = (void (*)(int, struct sockaddr *, void *))
  		    (inet6sw[ip6_protox[nxt]].pr_ctlinput);
  		if (ctlfunc) {
  			(void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
  			    &ip6cp);
  		}
  	}
  	*mp = m;
  	return (0);
  
    freeit:
  	m_freem(m);
  	*mp = NULL;
  	return (-1);
  }
  
  void
  icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
  {
  	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 in_conninfo inc;
  
  #if 0
  	/*
  	 * RFC2460 section 5, last paragraph.
  	 * even though minimum link MTU for IPv6 is IPV6_MMTU,
  	 * we may see ICMPv6 too big with mtu < IPV6_MMTU
  	 * due to packet translator in the middle.
  	 * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
  	 * special handling.
  	 */
  	if (mtu < IPV6_MMTU)
  		return;
  #endif
  
  	/*
  	 * we reject ICMPv6 too big with abnormally small value.
  	 * XXX what is the good definition of "abnormally small"?
  	 */
  	if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
  		return;
  
  	if (!validated)
  		return;
  
  	/*
  	 * In case the suggested mtu is less than IPV6_MMTU, we
  	 * only need to remember that it was for above mentioned
  	 * "alwaysfrag" case.
  	 * Try to be as close to the spec as possible.
  	 */
  	if (mtu < IPV6_MMTU)
  		mtu = IPV6_MMTU - 8;
  
  	bzero(&inc, sizeof(inc));
  	inc.inc_fibnum = M_GETFIB(m);
  	inc.inc_flags |= INC_ISIPV6;
  	inc.inc6_faddr = *dst;
  	if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
  		return;
  
  	if (mtu < tcp_maxmtu6(&inc, NULL)) {
  		tcp_hc_updatemtu(&inc, mtu);
  		ICMP6STAT_INC(icp6s_pmtuchg);
  	}
  }
  
  /*
   * 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)
   */
  static struct mbuf *
  ni6_input(struct mbuf *m, int off, struct prison *pr)
  {
  	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 in6_addr in6_subj; /* subject address */
  	struct ip6_hdr *ip6;
  	int oldfqdn = 0;	/* if 1, return pascal string (03 draft) */
  	char *subj = NULL;
  	struct in6_ifaddr *ia6 = NULL;
  
  	ip6 = mtod(m, struct ip6_hdr *);
  	ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
  
  	/*
  	 * Validate IPv6 source address.
  	 * The default configuration MUST be to refuse answering queries from
  	 * global-scope addresses according to RFC4602.
  	 * Notes:
  	 *  - it's not very clear what "refuse" means; this implementation
  	 *    simply drops it.
  	 *  - it's not very easy to identify global-scope (unicast) addresses
  	 *    since there are many prefixes for them.  It should be safer
  	 *    and in practice sufficient to check "all" but loopback and
  	 *    link-local (note that site-local unicast was deprecated and
  	 *    ULA is defined as global scope-wise)
  	 */
  	if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
  	    !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
  	    !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
  		goto bad;
  
  	/*
  	 * 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.
  	 * [RFC4602, Section 5.]
  	 */
  	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  		if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
  			goto bad;
  		/* else it's a link-local multicast, fine */
  	} else {		/* unicast or anycast */
  		ia6 = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
  		if (ia6 == NULL)
  			goto bad; /* XXX impossible */
  
  		if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
  		    !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
  			ifa_free(&ia6->ia_ifa);
  			nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
  				"a temporary address in %s:%d",
  			       __FILE__, __LINE__));
  			goto bad;
  		}
  		ifa_free(&ia6->ia_ifa);
  	}
  
  	/* 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(struct in6_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_copydata(m, off + sizeof(struct icmp6_nodeinfo),
  			    subjlen, (caddr_t)&in6_subj);
  			if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
  				goto bad;
  
  			subj = (char *)&in6_subj;
  			if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
  				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.
  			 */
  			mtx_lock(&pr->pr_mtx);
  			n = ni6_nametodns(pr->pr_hostname,
  			    strlen(pr->pr_hostname), 0);
  			mtx_unlock(&pr->pr_mtx);
  			if (!n || n->m_next || n->m_len == 0)
  				goto bad;
  			if (m->m_len < off + sizeof(struct icmp6_nodeinfo) +
  			    subjlen) {
  				m = m_pullup(m, off +
  				    sizeof(struct icmp6_nodeinfo) + subjlen);
  				if (m == NULL) {
  					IP6STAT_INC(ip6s_exthdrtoolong);
  					goto bad;
  				}
  			}
  			/* ip6 possibly invalid but not used after. */
  			ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
  			subj = (char *)(mtod(m, caddr_t) + off +
  			    sizeof(struct icmp6_nodeinfo));
  			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 ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
  			goto bad;
  		break;
  	case NI_QTYPE_NODEADDR:
  	case NI_QTYPE_IPV4ADDR:
  		if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 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, (struct in6_addr *)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? */
  		break;
  	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. */
  	if (replylen > MCLBYTES) {
  		/*
  		 * XXX: should we try to allocate more? But MCLBYTES
  		 * is probably much larger than IPV6_MMTU...
  		 */
  		goto bad;
  	}
  	if (replylen > MHLEN)
  		n = m_getcl(M_NOWAIT, m->m_type, M_PKTHDR);
  	else
  		n = m_gethdr(M_NOWAIT, m->m_type);
  	if (n == NULL) {
  		m_freem(m);
  		return (NULL);
  	}
  	m_move_pkthdr(n, m); /* just for recvif and FIB */
  	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 hostname?
  		 */
  		mtx_lock(&pr->pr_mtx);
  		n->m_next = ni6_nametodns(pr->pr_hostname,
  		    strlen(pr->pr_hostname), oldfqdn);
  		mtx_unlock(&pr->pr_mtx);
  		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);
  }
  
  /*
   * 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.
   *
   * old - return pascal string if non-zero
   */
  static struct mbuf *
  ni6_nametodns(const char *name, int namelen, int old)
  {
  	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. */
  	if (len > MLEN)
  		m = m_getcl(M_NOWAIT, MT_DATA, 0);
  	else
  		m = m_get(M_NOWAIT, MT_DATA);
  	if (m == NULL)
  		goto fail;
  
  	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(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(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
      struct in6_addr *subj)
  {
  	struct ifnet *ifp;
  	struct in6_ifaddr *ifa6;
  	struct ifaddr *ifa;
  	int addrs = 0, addrsofif, iffound = 0;
  	int niflags = ni6->ni_flags;
  
  	NET_EPOCH_ASSERT();
  
  	if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
  		switch (ni6->ni_code) {
  		case ICMP6_NI_SUBJ_IPV6:
  			if (subj == NULL) /* must be impossible... */
  				return (0);
  			break;
  		default:
  			/*
  			 * XXX: we only support IPv6 subject address for
  			 * this Qtype.
  			 */
  			return (0);
  		}
  	}
  
  	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
  		addrsofif = 0;
  		CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  			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, &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 &&
  			    (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
  				continue;
  			}
  			addrsofif++; /* count the address */
  		}
  		if (iffound) {
  			*ifpp = ifp;
  			return (addrsofif);
  		}
  
  		addrs += addrsofif;
  	}
  
  	return (addrs);
  }
  
  static int
  ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
      struct ifnet *ifp0, int resid)
  {
  	struct ifnet *ifp;
  	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;
  
  	NET_EPOCH_ASSERT();
  
  	if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
  		return (0);	/* needless to copy */
  
  	ifp = ifp0 ? ifp0 : CK_STAILQ_FIRST(&V_ifnet);
    again:
  
  	for (; ifp; ifp = CK_STAILQ_NEXT(ifp, if_link)) {
  		CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
  			if (ifa->ifa_addr->sa_family != AF_INET6)
  				continue;
  			ifa6 = (struct in6_ifaddr *)ifa;
  
  			if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
  			    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->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
  			    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 &&
  			    (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 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.
  			 */
  			if (ifa6->ia6_lifetime.ia6t_expire == 0)
  				ltime = ND6_INFINITE_LIFETIME;
  			else {
  				if (ifa6->ia6_lifetime.ia6t_expire >
  				    time_uptime)
  					ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_uptime);
  				else
  					ltime = 0;
  			}
  
  			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));
  			in6_clearscope((struct in6_addr *)cp); /* XXX */
  			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(struct mbuf **mp, int off)
  {
  	struct mbuf *m = *mp;
  	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  	struct inpcb *inp;
  	struct inpcb *last = NULL;
  	struct sockaddr_in6 fromsa;
  	struct icmp6_hdr *icmp6;
  	struct mbuf *opts = NULL;
  
  	NET_EPOCH_ASSERT();
  
  	/* This is assumed to be safe; icmp6_input() does a pullup. */
  	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
  
  	/*
  	 * XXX: the address may have embedded scope zone ID, which should be
  	 * hidden from applications.
  	 */
  	bzero(&fromsa, sizeof(fromsa));
  	fromsa.sin6_family = AF_INET6;
  	fromsa.sin6_len = sizeof(struct sockaddr_in6);
  	fromsa.sin6_addr = ip6->ip6_src;
  	if (sa6_recoverscope(&fromsa)) {
  		m_freem(m);
  		*mp = NULL;
  		return (IPPROTO_DONE);
  	}
  
  	CK_LIST_FOREACH(inp, &V_ripcb, inp_list) {
  		if ((inp->inp_vflag & INP_IPV6) == 0)
  			continue;
  		if (inp->inp_ip_p != IPPROTO_ICMPV6)
  			continue;
  		if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr) &&
  		   !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst))
  			continue;
  		if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr) &&
  		   !IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src))
  			continue;
  		INP_RLOCK(inp);
  		if (__predict_false(inp->inp_flags2 & INP_FREED)) {
  			INP_RUNLOCK(inp);
  			continue;
  		}
  		if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
  		    inp->in6p_icmp6filt)) {
  			INP_RUNLOCK(inp);
  			continue;
  		}
  		if (last != NULL) {
  			struct	mbuf *n = NULL;
  
  			/*
  			 * Recent network drivers tend to allocate a single
  			 * mbuf cluster, rather than to make a couple of
  			 * mbufs without clusters.  Also, since the IPv6 code
  			 * path tries to avoid m_pullup(), it is highly
  			 * probable that we still have an mbuf cluster here
  			 * even though the necessary length can be stored in an
  			 * mbuf's internal buffer.
  			 * Meanwhile, the default size of the receive socket
  			 * buffer for raw sockets is not so large.  This means
  			 * the possibility of packet loss is relatively higher
  			 * than before.  To avoid this scenario, we copy the
  			 * received data to a separate mbuf that does not use
  			 * a cluster, if possible.
  			 * XXX: it is better to copy the data after stripping
  			 * intermediate headers.
  			 */
  			if ((m->m_flags & M_EXT) && m->m_next == NULL &&
  			    m->m_len <= MHLEN) {
  				n = m_get(M_NOWAIT, m->m_type);
  				if (n != NULL) {
  					if (m_dup_pkthdr(n, m, M_NOWAIT)) {
  						bcopy(m->m_data, n->m_data,
  						      m->m_len);
  						n->m_len = m->m_len;
  					} else {
  						m_free(n);
  						n = NULL;
  					}
  				}
  			}
  			if (n != NULL ||
  			    (n = m_copym(m, 0, M_COPYALL, M_NOWAIT)) != NULL) {
  				if (last->inp_flags & INP_CONTROLOPTS)
  					ip6_savecontrol(last, n, &opts);
  				/* strip intermediate headers */
  				m_adj(n, off);
  				SOCKBUF_LOCK(&last->inp_socket->so_rcv);
  				if (sbappendaddr_locked(
  				    &last->inp_socket->so_rcv,
  				    (struct sockaddr *)&fromsa, n, opts)
  				    == 0) {
  					/* should notify about lost packet */
  					m_freem(n);
  					if (opts) {
  						m_freem(opts);
  					}
  					SOCKBUF_UNLOCK(
  					    &last->inp_socket->so_rcv);
  				} else
  					sorwakeup_locked(last->inp_socket);
  				opts = NULL;
  			}
  			INP_RUNLOCK(last);
  		}
  		last = inp;
  	}
  	if (last != NULL) {
  		if (last->inp_flags & INP_CONTROLOPTS)
  			ip6_savecontrol(last, m, &opts);
  		/* strip intermediate headers */
  		m_adj(m, off);
  
  		/* avoid using mbuf clusters if possible (see above) */
  		if ((m->m_flags & M_EXT) && m->m_next == NULL &&
  		    m->m_len <= MHLEN) {
  			struct mbuf *n;
  
  			n = m_get(M_NOWAIT, m->m_type);
  			if (n != NULL) {
  				if (m_dup_pkthdr(n, m, M_NOWAIT)) {
  					bcopy(m->m_data, n->m_data, m->m_len);
  					n->m_len = m->m_len;
  
  					m_freem(m);
  					m = n;
  				} else {
  					m_freem(n);
  					n = NULL;
  				}
  			}
  		}
  		SOCKBUF_LOCK(&last->inp_socket->so_rcv);
  		if (sbappendaddr_locked(&last->inp_socket->so_rcv,
  		    (struct sockaddr *)&fromsa, m, opts) == 0) {
  			m_freem(m);
  			if (opts)
  				m_freem(opts);
  			SOCKBUF_UNLOCK(&last->inp_socket->so_rcv);
  		} else
  			sorwakeup_locked(last->inp_socket);
  		INP_RUNLOCK(last);
  	} else {
  		m_freem(m);
  		IP6STAT_DEC(ip6s_delivered);
  	}
  	*mp = NULL;
  	return (IPPROTO_DONE);
  }
  
  /*
   * Reflect the ip6 packet back to the source.
   * OFF points to the icmp6 header, counted from the top of the mbuf.
   */
  static void
  icmp6_reflect(struct mbuf *m, size_t off)
  {
  	struct in6_addr src6, *srcp;
  	struct ip6_hdr *ip6;
  	struct icmp6_hdr *icmp6;
  	struct in6_ifaddr *ia = NULL;
  	struct ifnet *outif = NULL;
  	int plen;
  	int type, code, hlim;
  
  	/* 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. */
  	hlim = 0;
  	srcp = NULL;
  
  	/*
  	 * 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 should be VERY rare, but is possible
  	 * (for example) when we encounter an error while forwarding procedure
  	 * destined to a duplicated address of ours.
  	 */
  	if (!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  		ia = in6ifa_ifwithaddr(&ip6->ip6_dst, 0 /* XXX */);
  		if (ia != NULL && !(ia->ia6_flags &
  		    (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
  			src6 = ia->ia_addr.sin6_addr;
  			srcp = &src6;
  
  			if (m->m_pkthdr.rcvif != NULL) {
  				/* XXX: This may not be the outgoing interface */
  				hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
  			} else
  				hlim = V_ip6_defhlim;
  		}
  		if (ia != NULL)
  			ifa_free(&ia->ia_ifa);
  	}
  
  	if (srcp == NULL) {
  		int error;
  		struct in6_addr dst6;
  		uint32_t scopeid;
  
  		/*
  		 * 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.
  		 */
  		in6_splitscope(&ip6->ip6_src, &dst6, &scopeid);
  		error = in6_selectsrc_addr(M_GETFIB(m), &dst6,
  		    scopeid, NULL, &src6, &hlim);
  
  		if (error) {
  			char ip6buf[INET6_ADDRSTRLEN];
  			nd6log((LOG_DEBUG,
  			    "icmp6_reflect: source can't be determined: "
  			    "dst=%s, error=%d\n",
  			    ip6_sprintf(ip6buf, &ip6->ip6_dst), error));
  			goto bad;
  		}
  		srcp = &src6;
  	}
  	/*
  	 * ip6_input() drops a packet if its src is multicast.
  	 * So, the src is never multicast.
  	 */
  	ip6->ip6_dst = ip6->ip6_src;
  	ip6->ip6_src = *srcp;
  	ip6->ip6_flow = 0;
  	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
  	ip6->ip6_vfc |= IPV6_VERSION;
  	ip6->ip6_nxt = IPPROTO_ICMPV6;
  	ip6->ip6_hlim = hlim;
  
  	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);
  	m->m_pkthdr.rcvif = NULL;
  	ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
  	if (outif)
  		icmp6_ifoutstat_inc(outif, type, code);
  
  	return;
  
   bad:
  	m_freem(m);
  	return;
  }
  
  void
  icmp6_fasttimo(void)
  {
  
  	mld_fasttimo();
  }
  
  void
  icmp6_slowtimo(void)
  {
  
  	mld_slowtimo();
  }
  
  static const char *
  icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
      struct in6_addr *tgt6)
  {
  	static char buf[1024];
  	char ip6bufs[INET6_ADDRSTRLEN];
  	char ip6bufd[INET6_ADDRSTRLEN];
  	char ip6buft[INET6_ADDRSTRLEN];
  	snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
  	    ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
  	    ip6_sprintf(ip6buft, tgt6));
  	return buf;
  }
  
  void
  icmp6_redirect_input(struct mbuf *m, int off)
  {
  	struct ifnet *ifp;
  	struct ip6_hdr *ip6;
  	struct nd_redirect *nd_rd;
  	struct in6_addr src6, redtgt6, reddst6;
  	union nd_opts ndopts;
  	char ip6buf[INET6_ADDRSTRLEN];
  	char *lladdr;
  	int icmp6len, is_onlink, is_router, lladdrlen;
  
  	M_ASSERTPKTHDR(m);
  	KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
  
  	/* XXX if we are router, we don't update route by icmp6 redirect */
  	if (V_ip6_forwarding)
  		goto freeit;
  	if (!V_icmp6_rediraccept)
  		goto freeit;
  
  	/* RFC 6980: Nodes MUST silently ignore fragments */
  	if(m->m_flags & M_FRAGMENTED)
  		goto freeit;
  
  	ip6 = mtod(m, struct ip6_hdr *);
  	icmp6len = ntohs(ip6->ip6_plen);
  	if (m->m_len < off + icmp6len) {
  		m = m_pullup(m, off + icmp6len);
  		if (m == NULL) {
  			IP6STAT_INC(ip6s_exthdrtoolong);
  			return;
  		}
  	}
  	ip6 = mtod(m, struct ip6_hdr *);
  	nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
  
  	ifp = m->m_pkthdr.rcvif;
  	redtgt6 = nd_rd->nd_rd_target;
  	reddst6 = nd_rd->nd_rd_dst;
  
  	if (in6_setscope(&redtgt6, ifp, NULL) ||
  	    in6_setscope(&reddst6, ifp, NULL)) {
  		goto freeit;
  	}
  
  	/* validation */
  	src6 = ip6->ip6_src;
  	if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
  		nd6log((LOG_ERR,
  		    "ICMP6 redirect sent from %s rejected; "
  		    "must be from linklocal\n",
  		    ip6_sprintf(ip6buf, &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(ip6buf, &src6), ip6->ip6_hlim));
  		goto bad;
  	}
      {
  	/* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
  	struct nhop6_basic nh6;
  	struct in6_addr kdst;
  	uint32_t scopeid;
  
  	in6_splitscope(&reddst6, &kdst, &scopeid);
  	if (fib6_lookup_nh_basic(ifp->if_fib, &kdst, scopeid, 0, 0,&nh6)==0){
  		if ((nh6.nh_flags & NHF_GATEWAY) == 0) {
  			nd6log((LOG_ERR,
  			    "ICMP6 redirect rejected; no route "
  			    "with inet6 gateway found for redirect dst: %s\n",
  			    icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
  			goto bad;
  		}
  
  		/*
  		 * Embed scope zone id into next hop address, since
  		 * fib6_lookup_nh_basic() returns address without embedded
  		 * scope zone id.
  		 */
  		if (in6_setscope(&nh6.nh_addr, m->m_pkthdr.rcvif, NULL))
  			goto freeit;
  
  		if (IN6_ARE_ADDR_EQUAL(&src6, &nh6.nh_addr) == 0) {
  			nd6log((LOG_ERR,
  			    "ICMP6 redirect rejected; "
  			    "not equal to gw-for-src=%s (must be same): "
  			    "%s\n",
  			    ip6_sprintf(ip6buf, &nh6.nh_addr),
  			    icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
  			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;
  	}
      }
  	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;
  	}
  
  	icmp6len -= sizeof(*nd_rd);
  	nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
  	if (nd6_options(&ndopts) < 0) {
  		nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
  		    __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
  		/* nd6_options have incremented stats */
  		goto freeit;
  	}
  
  	lladdr = NULL;
  	lladdrlen = 0;
  	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 (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
  		nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
  		    "(if %d, icmp6 packet %d): %s\n",
  		    __func__, ip6_sprintf(ip6buf, &redtgt6),
  		    ifp->if_addrlen, lladdrlen - 2,
  		    icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
  		goto bad;
  	}
  
  	/* Validation passed. */
  
  	/* RFC 2461 8.3 */
  	nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
  	    is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
  
  	/*
  	 * Install a gateway route in the better-router case or an interface
  	 * route in the on-link-destination case.
  	 */
  	{
  		struct sockaddr_in6 sdst;
  		struct sockaddr_in6 sgw;
  		struct sockaddr_in6 ssrc;
  		struct sockaddr *gw;
  		int rt_flags;
  		u_int fibnum;
  
  		bzero(&sdst, sizeof(sdst));
  		bzero(&ssrc, sizeof(ssrc));
  		sdst.sin6_family = ssrc.sin6_family = AF_INET6;
  		sdst.sin6_len = ssrc.sin6_len = sizeof(struct sockaddr_in6);
  		bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
  		bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
  		rt_flags = 0;
  		if (is_router) {
  			bzero(&sgw, sizeof(sgw));
  			sgw.sin6_family = AF_INET6;
  			sgw.sin6_len = sizeof(struct sockaddr_in6);
  			bcopy(&redtgt6, &sgw.sin6_addr,
  				sizeof(struct in6_addr));
  			gw = (struct sockaddr *)&sgw;
  			rt_flags |= RTF_GATEWAY;
  		} else
  			gw = ifp->if_addr->ifa_addr;
  		for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
  			rib_add_redirect(fibnum, (struct sockaddr *)&sdst, gw,
  			    (struct sockaddr *)&ssrc, ifp, rt_flags,
  			    V_icmp6_redirtimeout);
  	}
  	/* 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);
      }
  
   freeit:
  	m_freem(m);
  	return;
  
   bad:
  	ICMP6STAT_INC(icp6s_badredirect);
  	m_freem(m);
  }
  
  void
  icmp6_redirect_output(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 m_tag *mtag;
  	struct ip6_hdr *ip6;	/* m as struct ip6_hdr */
  	struct nd_redirect *nd_rd;
  	struct llentry *ln = NULL;
  	size_t maxlen;
  	u_char *p;
  	struct ifnet *outif = NULL;
  	struct sockaddr_in6 src_sa;
  
  	icmp6_errcount(ND_REDIRECT, 0);
  
  	/* if we are not router, we don't send icmp6 redirect */
  	if (!V_ip6_forwarding)
  		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;
  	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
  	m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
  	if (m == NULL)
  		goto fail;
  	M_SETFIB(m, rt->rt_fibnum);
  	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;
  		/* XXXRW: reference released prematurely. */
  		ifa_free(&ia->ia_ifa);
  	}
  
  	/* 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 */
  		int len;
  		struct nd_opt_hdr *nd_opt;
  		char *lladdr;
  
  		ln = nd6_lookup(router_ll6, 0, ifp);
  		if (ln == NULL)
  			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 (ln->la_flags & LLE_VALID) {
  			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(ln->ll_addr, lladdr, ifp->if_addrlen);
  			p += len;
  		}
  	}
  nolladdropt:
  	if (ln != NULL)
  		LLE_RUNLOCK(ln);
  		
  	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", __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_tag_delete_chain(m0, NULL);
  		m0->m_flags &= ~M_PKTHDR;
  		m->m_next = m0;
  		m->m_pkthdr.len = m->m_len + m0->m_len;
  		m0 = NULL;
  	}
  noredhdropt:;
  	if (m0) {
  		m_freem(m0);
  		m0 = NULL;
  	}
  
  	/* XXX: clear embedded link IDs in the inner header */
  	in6_clearscope(&sip6->ip6_src);
  	in6_clearscope(&sip6->ip6_dst);
  	in6_clearscope(&nd_rd->nd_rd_target);
  	in6_clearscope(&nd_rd->nd_rd_dst);
  
  	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));
  
          if (send_sendso_input_hook != NULL) {
  		mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
  			M_NOWAIT);
  		if (mtag == NULL)
  			goto fail;
  		*(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
  		m_tag_prepend(m, mtag);
  	}
  
  	/* send the packet to outside... */
  	ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
  	if (outif) {
  		icmp6_ifstat_inc(outif, ifs6_out_msg);
  		icmp6_ifstat_inc(outif, ifs6_out_redirect);
  	}
  	ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
  
  	return;
  
  fail:
  	if (m)
  		m_freem(m);
  	if (m0)
  		m_freem(m0);
  }
  
  /*
   * ICMPv6 socket option processing.
   */
  int
  icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
  {
  	int error = 0;
  	int optlen;
  	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;
  
  	if (level != IPPROTO_ICMPV6) {
  		return EINVAL;
  	}
  
  	switch (op) {
  	case PRCO_SETOPT:
  		switch (optname) {
  		case ICMP6_FILTER:
  		    {
  			struct icmp6_filter ic6f;
  
  			if (optlen != sizeof(ic6f)) {
  				error = EMSGSIZE;
  				break;
  			}
  			error = sooptcopyin(sopt, &ic6f, optlen, optlen);
  			if (error == 0) {
  				INP_WLOCK(inp);
  				*inp->in6p_icmp6filt = ic6f;
  				INP_WUNLOCK(inp);
  			}
  			break;
  		    }
  
  		default:
  			error = ENOPROTOOPT;
  			break;
  		}
  		break;
  
  	case PRCO_GETOPT:
  		switch (optname) {
  		case ICMP6_FILTER:
  		    {
  			struct icmp6_filter ic6f;
  
  			INP_RLOCK(inp);
  			ic6f = *inp->in6p_icmp6filt;
  			INP_RUNLOCK(inp);
  			error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
  			break;
  		    }
  
  		default:
  			error = ENOPROTOOPT;
  			break;
  		}
  		break;
  	}
  
  	return (error);
  }
  
  /*
   * 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?
   *
   * dst - not used at this moment
   * type - not used at this moment
   * code - not used at this moment
   */
  static int
  icmp6_ratelimit(const struct in6_addr *dst, const int type,
      const int code)
  {
  	int ret;
  
  	ret = 0;	/* okay to send */
  
  	/* PPS limit */
  	if (!ppsratecheck(&V_icmp6errppslim_last, &V_icmp6errpps_count,
  	    V_icmp6errppslim)) {
  		/* The packet is subject to rate limit */
  		ret++;
  	}
  
  	return ret;
  }
  