The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/netinet6/icmp6.c

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    1 /*-
    2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. Neither the name of the project nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  *      $KAME: icmp6.c,v 1.211 2001/04/04 05:56:20 itojun Exp $
   30  */
   31 
   32 /*-
   33  * Copyright (c) 1982, 1986, 1988, 1993
   34  *      The Regents of the University of California.  All rights reserved.
   35  *
   36  * Redistribution and use in source and binary forms, with or without
   37  * modification, are permitted provided that the following conditions
   38  * are met:
   39  * 1. Redistributions of source code must retain the above copyright
   40  *    notice, this list of conditions and the following disclaimer.
   41  * 2. Redistributions in binary form must reproduce the above copyright
   42  *    notice, this list of conditions and the following disclaimer in the
   43  *    documentation and/or other materials provided with the distribution.
   44  * 4. Neither the name of the University nor the names of its contributors
   45  *    may be used to endorse or promote products derived from this software
   46  *    without specific prior written permission.
   47  *
   48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   58  * SUCH DAMAGE.
   59  *
   60  *      @(#)ip_icmp.c   8.2 (Berkeley) 1/4/94
   61  */
   62 
   63 #include <sys/cdefs.h>
   64 __FBSDID("$FreeBSD: releng/9.1/sys/netinet6/icmp6.c 238242 2012-07-08 12:34:12Z bz $");
   65 
   66 #include "opt_inet.h"
   67 #include "opt_inet6.h"
   68 #include "opt_ipsec.h"
   69 
   70 #include <sys/param.h>
   71 #include <sys/domain.h>
   72 #include <sys/jail.h>
   73 #include <sys/kernel.h>
   74 #include <sys/lock.h>
   75 #include <sys/malloc.h>
   76 #include <sys/mbuf.h>
   77 #include <sys/proc.h>
   78 #include <sys/protosw.h>
   79 #include <sys/signalvar.h>
   80 #include <sys/socket.h>
   81 #include <sys/socketvar.h>
   82 #include <sys/sx.h>
   83 #include <sys/syslog.h>
   84 #include <sys/systm.h>
   85 #include <sys/time.h>
   86 
   87 #include <net/if.h>
   88 #include <net/if_dl.h>
   89 #include <net/if_llatbl.h>
   90 #include <net/if_types.h>
   91 #include <net/route.h>
   92 #include <net/vnet.h>
   93 
   94 #include <netinet/in.h>
   95 #include <netinet/in_pcb.h>
   96 #include <netinet/in_var.h>
   97 #include <netinet/ip6.h>
   98 #include <netinet/icmp6.h>
   99 #include <netinet/tcp_var.h>
  100 
  101 #include <netinet6/in6_ifattach.h>
  102 #include <netinet6/in6_pcb.h>
  103 #include <netinet6/ip6protosw.h>
  104 #include <netinet6/ip6_var.h>
  105 #include <netinet6/scope6_var.h>
  106 #include <netinet6/mld6_var.h>
  107 #include <netinet6/nd6.h>
  108 #include <netinet6/send.h>
  109 
  110 #ifdef IPSEC
  111 #include <netipsec/ipsec.h>
  112 #include <netipsec/key.h>
  113 #endif
  114 
  115 extern struct domain inet6domain;
  116 
  117 VNET_DEFINE(struct icmp6stat, icmp6stat);
  118 
  119 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
  120 VNET_DECLARE(struct inpcbhead, ripcb);
  121 VNET_DECLARE(int, icmp6errppslim);
  122 static VNET_DEFINE(int, icmp6errpps_count) = 0;
  123 static VNET_DEFINE(struct timeval, icmp6errppslim_last);
  124 VNET_DECLARE(int, icmp6_nodeinfo);
  125 
  126 #define V_ripcbinfo                     VNET(ripcbinfo)
  127 #define V_ripcb                         VNET(ripcb)
  128 #define V_icmp6errppslim                VNET(icmp6errppslim)
  129 #define V_icmp6errpps_count             VNET(icmp6errpps_count)
  130 #define V_icmp6errppslim_last           VNET(icmp6errppslim_last)
  131 #define V_icmp6_nodeinfo                VNET(icmp6_nodeinfo)
  132 
  133 static void icmp6_errcount(struct icmp6errstat *, int, int);
  134 static int icmp6_rip6_input(struct mbuf **, int);
  135 static int icmp6_ratelimit(const struct in6_addr *, const int, const int);
  136 static const char *icmp6_redirect_diag __P((struct in6_addr *,
  137         struct in6_addr *, struct in6_addr *));
  138 static struct mbuf *ni6_input(struct mbuf *, int);
  139 static struct mbuf *ni6_nametodns(const char *, int, int);
  140 static int ni6_dnsmatch(const char *, int, const char *, int);
  141 static int ni6_addrs __P((struct icmp6_nodeinfo *, struct mbuf *,
  142                           struct ifnet **, struct in6_addr *));
  143 static int ni6_store_addrs __P((struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
  144                                 struct ifnet *, int));
  145 static int icmp6_notify_error(struct mbuf **, int, int, int);
  146 
  147 /*
  148  * Kernel module interface for updating icmp6stat.  The argument is an index
  149  * into icmp6stat treated as an array of u_quad_t.  While this encodes the
  150  * general layout of icmp6stat into the caller, it doesn't encode its
  151  * location, so that future changes to add, for example, per-CPU stats
  152  * support won't cause binary compatibility problems for kernel modules.
  153  */
  154 void
  155 kmod_icmp6stat_inc(int statnum)
  156 {
  157 
  158         (*((u_quad_t *)&V_icmp6stat + statnum))++;
  159 }
  160 
  161 static void
  162 icmp6_errcount(struct icmp6errstat *stat, int type, int code)
  163 {
  164         switch (type) {
  165         case ICMP6_DST_UNREACH:
  166                 switch (code) {
  167                 case ICMP6_DST_UNREACH_NOROUTE:
  168                         stat->icp6errs_dst_unreach_noroute++;
  169                         return;
  170                 case ICMP6_DST_UNREACH_ADMIN:
  171                         stat->icp6errs_dst_unreach_admin++;
  172                         return;
  173                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
  174                         stat->icp6errs_dst_unreach_beyondscope++;
  175                         return;
  176                 case ICMP6_DST_UNREACH_ADDR:
  177                         stat->icp6errs_dst_unreach_addr++;
  178                         return;
  179                 case ICMP6_DST_UNREACH_NOPORT:
  180                         stat->icp6errs_dst_unreach_noport++;
  181                         return;
  182                 }
  183                 break;
  184         case ICMP6_PACKET_TOO_BIG:
  185                 stat->icp6errs_packet_too_big++;
  186                 return;
  187         case ICMP6_TIME_EXCEEDED:
  188                 switch (code) {
  189                 case ICMP6_TIME_EXCEED_TRANSIT:
  190                         stat->icp6errs_time_exceed_transit++;
  191                         return;
  192                 case ICMP6_TIME_EXCEED_REASSEMBLY:
  193                         stat->icp6errs_time_exceed_reassembly++;
  194                         return;
  195                 }
  196                 break;
  197         case ICMP6_PARAM_PROB:
  198                 switch (code) {
  199                 case ICMP6_PARAMPROB_HEADER:
  200                         stat->icp6errs_paramprob_header++;
  201                         return;
  202                 case ICMP6_PARAMPROB_NEXTHEADER:
  203                         stat->icp6errs_paramprob_nextheader++;
  204                         return;
  205                 case ICMP6_PARAMPROB_OPTION:
  206                         stat->icp6errs_paramprob_option++;
  207                         return;
  208                 }
  209                 break;
  210         case ND_REDIRECT:
  211                 stat->icp6errs_redirect++;
  212                 return;
  213         }
  214         stat->icp6errs_unknown++;
  215 }
  216 
  217 /*
  218  * A wrapper function for icmp6_error() necessary when the erroneous packet
  219  * may not contain enough scope zone information.
  220  */
  221 void
  222 icmp6_error2(struct mbuf *m, int type, int code, int param,
  223     struct ifnet *ifp)
  224 {
  225         struct ip6_hdr *ip6;
  226 
  227         if (ifp == NULL)
  228                 return;
  229 
  230 #ifndef PULLDOWN_TEST
  231         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
  232 #else
  233         if (m->m_len < sizeof(struct ip6_hdr)) {
  234                 m = m_pullup(m, sizeof(struct ip6_hdr));
  235                 if (m == NULL)
  236                         return;
  237         }
  238 #endif
  239 
  240         ip6 = mtod(m, struct ip6_hdr *);
  241 
  242         if (in6_setscope(&ip6->ip6_src, ifp, NULL) != 0)
  243                 return;
  244         if (in6_setscope(&ip6->ip6_dst, ifp, NULL) != 0)
  245                 return;
  246 
  247         icmp6_error(m, type, code, param);
  248 }
  249 
  250 /*
  251  * Generate an error packet of type error in response to bad IP6 packet.
  252  */
  253 void
  254 icmp6_error(struct mbuf *m, int type, int code, int param)
  255 {
  256         struct ip6_hdr *oip6, *nip6;
  257         struct icmp6_hdr *icmp6;
  258         u_int preplen;
  259         int off;
  260         int nxt;
  261 
  262         ICMP6STAT_INC(icp6s_error);
  263 
  264         /* count per-type-code statistics */
  265         icmp6_errcount(&V_icmp6stat.icp6s_outerrhist, type, code);
  266 
  267 #ifdef M_DECRYPTED      /*not openbsd*/
  268         if (m->m_flags & M_DECRYPTED) {
  269                 ICMP6STAT_INC(icp6s_canterror);
  270                 goto freeit;
  271         }
  272 #endif
  273 
  274 #ifndef PULLDOWN_TEST
  275         IP6_EXTHDR_CHECK(m, 0, sizeof(struct ip6_hdr), );
  276 #else
  277         if (m->m_len < sizeof(struct ip6_hdr)) {
  278                 m = m_pullup(m, sizeof(struct ip6_hdr));
  279                 if (m == NULL)
  280                         return;
  281         }
  282 #endif
  283         oip6 = mtod(m, struct ip6_hdr *);
  284 
  285         /*
  286          * If the destination address of the erroneous packet is a multicast
  287          * address, or the packet was sent using link-layer multicast,
  288          * we should basically suppress sending an error (RFC 2463, Section
  289          * 2.4).
  290          * We have two exceptions (the item e.2 in that section):
  291          * - the Packet Too Big message can be sent for path MTU discovery.
  292          * - the Parameter Problem Message that can be allowed an icmp6 error
  293          *   in the option type field.  This check has been done in
  294          *   ip6_unknown_opt(), so we can just check the type and code.
  295          */
  296         if ((m->m_flags & (M_BCAST|M_MCAST) ||
  297              IN6_IS_ADDR_MULTICAST(&oip6->ip6_dst)) &&
  298             (type != ICMP6_PACKET_TOO_BIG &&
  299              (type != ICMP6_PARAM_PROB ||
  300               code != ICMP6_PARAMPROB_OPTION)))
  301                 goto freeit;
  302 
  303         /*
  304          * RFC 2463, 2.4 (e.5): source address check.
  305          * XXX: the case of anycast source?
  306          */
  307         if (IN6_IS_ADDR_UNSPECIFIED(&oip6->ip6_src) ||
  308             IN6_IS_ADDR_MULTICAST(&oip6->ip6_src))
  309                 goto freeit;
  310 
  311         /*
  312          * If we are about to send ICMPv6 against ICMPv6 error/redirect,
  313          * don't do it.
  314          */
  315         nxt = -1;
  316         off = ip6_lasthdr(m, 0, IPPROTO_IPV6, &nxt);
  317         if (off >= 0 && nxt == IPPROTO_ICMPV6) {
  318                 struct icmp6_hdr *icp;
  319 
  320 #ifndef PULLDOWN_TEST
  321                 IP6_EXTHDR_CHECK(m, 0, off + sizeof(struct icmp6_hdr), );
  322                 icp = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
  323 #else
  324                 IP6_EXTHDR_GET(icp, struct icmp6_hdr *, m, off,
  325                         sizeof(*icp));
  326                 if (icp == NULL) {
  327                         ICMP6STAT_INC(icp6s_tooshort);
  328                         return;
  329                 }
  330 #endif
  331                 if (icp->icmp6_type < ICMP6_ECHO_REQUEST ||
  332                     icp->icmp6_type == ND_REDIRECT) {
  333                         /*
  334                          * ICMPv6 error
  335                          * Special case: for redirect (which is
  336                          * informational) we must not send icmp6 error.
  337                          */
  338                         ICMP6STAT_INC(icp6s_canterror);
  339                         goto freeit;
  340                 } else {
  341                         /* ICMPv6 informational - send the error */
  342                 }
  343         } else {
  344                 /* non-ICMPv6 - send the error */
  345         }
  346 
  347         oip6 = mtod(m, struct ip6_hdr *); /* adjust pointer */
  348 
  349         /* Finally, do rate limitation check. */
  350         if (icmp6_ratelimit(&oip6->ip6_src, type, code)) {
  351                 ICMP6STAT_INC(icp6s_toofreq);
  352                 goto freeit;
  353         }
  354 
  355         /*
  356          * OK, ICMP6 can be generated.
  357          */
  358 
  359         if (m->m_pkthdr.len >= ICMPV6_PLD_MAXLEN)
  360                 m_adj(m, ICMPV6_PLD_MAXLEN - m->m_pkthdr.len);
  361 
  362         preplen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
  363         M_PREPEND(m, preplen, M_DONTWAIT);      /* FIB is also copied over. */
  364         if (m && m->m_len < preplen)
  365                 m = m_pullup(m, preplen);
  366         if (m == NULL) {
  367                 nd6log((LOG_DEBUG, "ENOBUFS in icmp6_error %d\n", __LINE__));
  368                 return;
  369         }
  370 
  371         nip6 = mtod(m, struct ip6_hdr *);
  372         nip6->ip6_src  = oip6->ip6_src;
  373         nip6->ip6_dst  = oip6->ip6_dst;
  374 
  375         in6_clearscope(&oip6->ip6_src);
  376         in6_clearscope(&oip6->ip6_dst);
  377 
  378         icmp6 = (struct icmp6_hdr *)(nip6 + 1);
  379         icmp6->icmp6_type = type;
  380         icmp6->icmp6_code = code;
  381         icmp6->icmp6_pptr = htonl((u_int32_t)param);
  382 
  383         /*
  384          * icmp6_reflect() is designed to be in the input path.
  385          * icmp6_error() can be called from both input and output path,
  386          * and if we are in output path rcvif could contain bogus value.
  387          * clear m->m_pkthdr.rcvif for safety, we should have enough scope
  388          * information in ip header (nip6).
  389          */
  390         m->m_pkthdr.rcvif = NULL;
  391 
  392         ICMP6STAT_INC(icp6s_outhist[type]);
  393         icmp6_reflect(m, sizeof(struct ip6_hdr)); /* header order: IPv6 - ICMPv6 */
  394 
  395         return;
  396 
  397   freeit:
  398         /*
  399          * If we can't tell whether or not we can generate ICMP6, free it.
  400          */
  401         m_freem(m);
  402 }
  403 
  404 /*
  405  * Process a received ICMP6 message.
  406  */
  407 int
  408 icmp6_input(struct mbuf **mp, int *offp, int proto)
  409 {
  410         struct mbuf *m = *mp, *n;
  411         struct ifnet *ifp;
  412         struct ip6_hdr *ip6, *nip6;
  413         struct icmp6_hdr *icmp6, *nicmp6;
  414         int off = *offp;
  415         int icmp6len = m->m_pkthdr.len - *offp;
  416         int code, sum, noff;
  417         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  418         int ip6len, error;
  419 
  420         ifp = m->m_pkthdr.rcvif;
  421 
  422 #ifndef PULLDOWN_TEST
  423         IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_hdr), IPPROTO_DONE);
  424         /* m might change if M_LOOP.  So, call mtod after this */
  425 #endif
  426 
  427         /*
  428          * Locate icmp6 structure in mbuf, and check
  429          * that not corrupted and of at least minimum length
  430          */
  431 
  432         ip6 = mtod(m, struct ip6_hdr *);
  433         ip6len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
  434         if (icmp6len < sizeof(struct icmp6_hdr)) {
  435                 ICMP6STAT_INC(icp6s_tooshort);
  436                 goto freeit;
  437         }
  438 
  439         /*
  440          * Check multicast group membership.
  441          * Note: SSM filters are not applied for ICMPv6 traffic.
  442          */
  443         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
  444                 struct in6_multi        *inm;
  445 
  446                 inm = in6m_lookup(ifp, &ip6->ip6_dst);
  447                 if (inm == NULL) {
  448                         IP6STAT_INC(ip6s_notmember);
  449                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
  450                         goto freeit;
  451                 }
  452         }
  453 
  454         /*
  455          * calculate the checksum
  456          */
  457 #ifndef PULLDOWN_TEST
  458         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
  459 #else
  460         IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
  461         if (icmp6 == NULL) {
  462                 ICMP6STAT_INC(icp6s_tooshort);
  463                 return IPPROTO_DONE;
  464         }
  465 #endif
  466         code = icmp6->icmp6_code;
  467 
  468         if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
  469                 nd6log((LOG_ERR,
  470                     "ICMP6 checksum error(%d|%x) %s\n",
  471                     icmp6->icmp6_type, sum,
  472                     ip6_sprintf(ip6bufs, &ip6->ip6_src)));
  473                 ICMP6STAT_INC(icp6s_checksum);
  474                 goto freeit;
  475         }
  476 
  477         if (faithprefix_p != NULL && (*faithprefix_p)(&ip6->ip6_dst)) {
  478                 /*
  479                  * Deliver very specific ICMP6 type only.
  480                  * This is important to deliver TOOBIG.  Otherwise PMTUD
  481                  * will not work.
  482                  */
  483                 switch (icmp6->icmp6_type) {
  484                 case ICMP6_DST_UNREACH:
  485                 case ICMP6_PACKET_TOO_BIG:
  486                 case ICMP6_TIME_EXCEEDED:
  487                         break;
  488                 default:
  489                         goto freeit;
  490                 }
  491         }
  492 
  493         ICMP6STAT_INC(icp6s_inhist[icmp6->icmp6_type]);
  494         icmp6_ifstat_inc(ifp, ifs6_in_msg);
  495         if (icmp6->icmp6_type < ICMP6_INFOMSG_MASK)
  496                 icmp6_ifstat_inc(ifp, ifs6_in_error);
  497 
  498         switch (icmp6->icmp6_type) {
  499         case ICMP6_DST_UNREACH:
  500                 icmp6_ifstat_inc(ifp, ifs6_in_dstunreach);
  501                 switch (code) {
  502                 case ICMP6_DST_UNREACH_NOROUTE:
  503                         code = PRC_UNREACH_NET;
  504                         break;
  505                 case ICMP6_DST_UNREACH_ADMIN:
  506                         icmp6_ifstat_inc(ifp, ifs6_in_adminprohib);
  507                         code = PRC_UNREACH_PROTOCOL; /* is this a good code? */
  508                         break;
  509                 case ICMP6_DST_UNREACH_ADDR:
  510                         code = PRC_HOSTDEAD;
  511                         break;
  512                 case ICMP6_DST_UNREACH_BEYONDSCOPE:
  513                         /* I mean "source address was incorrect." */
  514                         code = PRC_PARAMPROB;
  515                         break;
  516                 case ICMP6_DST_UNREACH_NOPORT:
  517                         code = PRC_UNREACH_PORT;
  518                         break;
  519                 default:
  520                         goto badcode;
  521                 }
  522                 goto deliver;
  523                 break;
  524 
  525         case ICMP6_PACKET_TOO_BIG:
  526                 icmp6_ifstat_inc(ifp, ifs6_in_pkttoobig);
  527 
  528                 /* validation is made in icmp6_mtudisc_update */
  529 
  530                 code = PRC_MSGSIZE;
  531 
  532                 /*
  533                  * Updating the path MTU will be done after examining
  534                  * intermediate extension headers.
  535                  */
  536                 goto deliver;
  537                 break;
  538 
  539         case ICMP6_TIME_EXCEEDED:
  540                 icmp6_ifstat_inc(ifp, ifs6_in_timeexceed);
  541                 switch (code) {
  542                 case ICMP6_TIME_EXCEED_TRANSIT:
  543                         code = PRC_TIMXCEED_INTRANS;
  544                         break;
  545                 case ICMP6_TIME_EXCEED_REASSEMBLY:
  546                         code = PRC_TIMXCEED_REASS;
  547                         break;
  548                 default:
  549                         goto badcode;
  550                 }
  551                 goto deliver;
  552                 break;
  553 
  554         case ICMP6_PARAM_PROB:
  555                 icmp6_ifstat_inc(ifp, ifs6_in_paramprob);
  556                 switch (code) {
  557                 case ICMP6_PARAMPROB_NEXTHEADER:
  558                         code = PRC_UNREACH_PROTOCOL;
  559                         break;
  560                 case ICMP6_PARAMPROB_HEADER:
  561                 case ICMP6_PARAMPROB_OPTION:
  562                         code = PRC_PARAMPROB;
  563                         break;
  564                 default:
  565                         goto badcode;
  566                 }
  567                 goto deliver;
  568                 break;
  569 
  570         case ICMP6_ECHO_REQUEST:
  571                 icmp6_ifstat_inc(ifp, ifs6_in_echo);
  572                 if (code != 0)
  573                         goto badcode;
  574                 if ((n = m_copy(m, 0, M_COPYALL)) == NULL) {
  575                         /* Give up remote */
  576                         break;
  577                 }
  578                 if ((n->m_flags & M_EXT) != 0
  579                  || n->m_len < off + sizeof(struct icmp6_hdr)) {
  580                         struct mbuf *n0 = n;
  581                         const int maxlen = sizeof(*nip6) + sizeof(*nicmp6);
  582                         int n0len;
  583 
  584                         MGETHDR(n, M_DONTWAIT, n0->m_type);
  585                         n0len = n0->m_pkthdr.len;       /* save for use below */
  586                         if (n)
  587                                 M_MOVE_PKTHDR(n, n0);   /* FIB copied. */
  588                         if (n && maxlen >= MHLEN) {
  589                                 MCLGET(n, M_DONTWAIT);
  590                                 if ((n->m_flags & M_EXT) == 0) {
  591                                         m_free(n);
  592                                         n = NULL;
  593                                 }
  594                         }
  595                         if (n == NULL) {
  596                                 /* Give up remote */
  597                                 m_freem(n0);
  598                                 break;
  599                         }
  600                         /*
  601                          * Copy IPv6 and ICMPv6 only.
  602                          */
  603                         nip6 = mtod(n, struct ip6_hdr *);
  604                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
  605                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
  606                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
  607                         noff = sizeof(struct ip6_hdr);
  608                         /* new mbuf contains only ipv6+icmpv6 headers */
  609                         n->m_len = noff + sizeof(struct icmp6_hdr);
  610                         /*
  611                          * Adjust mbuf.  ip6_plen will be adjusted in
  612                          * ip6_output().
  613                          */
  614                         m_adj(n0, off + sizeof(struct icmp6_hdr));
  615                         /* recalculate complete packet size */
  616                         n->m_pkthdr.len = n0len + (noff - off);
  617                         n->m_next = n0;
  618                 } else {
  619                         nip6 = mtod(n, struct ip6_hdr *);
  620                         IP6_EXTHDR_GET(nicmp6, struct icmp6_hdr *, n, off,
  621                             sizeof(*nicmp6));
  622                         noff = off;
  623                 }
  624                 nicmp6->icmp6_type = ICMP6_ECHO_REPLY;
  625                 nicmp6->icmp6_code = 0;
  626                 if (n) {
  627                         ICMP6STAT_INC(icp6s_reflect);
  628                         ICMP6STAT_INC(icp6s_outhist[ICMP6_ECHO_REPLY]);
  629                         icmp6_reflect(n, noff);
  630                 }
  631                 break;
  632 
  633         case ICMP6_ECHO_REPLY:
  634                 icmp6_ifstat_inc(ifp, ifs6_in_echoreply);
  635                 if (code != 0)
  636                         goto badcode;
  637                 break;
  638 
  639         case MLD_LISTENER_QUERY:
  640         case MLD_LISTENER_REPORT:
  641         case MLD_LISTENER_DONE:
  642         case MLDV2_LISTENER_REPORT:
  643                 /*
  644                  * Drop MLD traffic which is not link-local, has a hop limit
  645                  * of greater than 1 hop, or which does not have the
  646                  * IPv6 HBH Router Alert option.
  647                  * As IPv6 HBH options are stripped in ip6_input() we must
  648                  * check an mbuf header flag.
  649                  * XXX Should we also sanity check that these messages
  650                  * were directed to a link-local multicast prefix?
  651                  */
  652                 if ((ip6->ip6_hlim != 1) || (m->m_flags & M_RTALERT_MLD) == 0)
  653                         goto freeit;
  654                 if (mld_input(m, off, icmp6len) != 0)
  655                         return (IPPROTO_DONE);
  656                 /* m stays. */
  657                 break;
  658 
  659         case ICMP6_WRUREQUEST:  /* ICMP6_FQDN_QUERY */
  660             {
  661                 enum { WRU, FQDN } mode;
  662 
  663                 if (!V_icmp6_nodeinfo)
  664                         break;
  665 
  666                 if (icmp6len == sizeof(struct icmp6_hdr) + 4)
  667                         mode = WRU;
  668                 else if (icmp6len >= sizeof(struct icmp6_nodeinfo))
  669                         mode = FQDN;
  670                 else
  671                         goto badlen;
  672 
  673                 if (mode == FQDN) {
  674 #ifndef PULLDOWN_TEST
  675                         IP6_EXTHDR_CHECK(m, off, sizeof(struct icmp6_nodeinfo),
  676                             IPPROTO_DONE);
  677 #endif
  678                         n = m_copy(m, 0, M_COPYALL);
  679                         if (n)
  680                                 n = ni6_input(n, off);
  681                         /* XXX meaningless if n == NULL */
  682                         noff = sizeof(struct ip6_hdr);
  683                 } else {
  684                         struct prison *pr;
  685                         u_char *p;
  686                         int maxlen, maxhlen, hlen;
  687 
  688                         /*
  689                          * XXX: this combination of flags is pointless,
  690                          * but should we keep this for compatibility?
  691                          */
  692                         if ((V_icmp6_nodeinfo & 5) != 5)
  693                                 break;
  694 
  695                         if (code != 0)
  696                                 goto badcode;
  697                         maxlen = sizeof(*nip6) + sizeof(*nicmp6) + 4;
  698                         if (maxlen >= MCLBYTES) {
  699                                 /* Give up remote */
  700                                 break;
  701                         }
  702                         MGETHDR(n, M_DONTWAIT, m->m_type);
  703                         if (n && maxlen > MHLEN) {
  704                                 MCLGET(n, M_DONTWAIT);
  705                                 if ((n->m_flags & M_EXT) == 0) {
  706                                         m_free(n);
  707                                         n = NULL;
  708                                 }
  709                         }
  710                         if (n && !m_dup_pkthdr(n, m, M_DONTWAIT)) {
  711                                 /*
  712                                  * Previous code did a blind M_COPY_PKTHDR
  713                                  * and said "just for rcvif".  If true, then
  714                                  * we could tolerate the dup failing (due to
  715                                  * the deep copy of the tag chain).  For now
  716                                  * be conservative and just fail.
  717                                  */
  718                                 m_free(n);
  719                                 n = NULL;
  720                         }
  721                         if (n == NULL) {
  722                                 /* Give up remote */
  723                                 break;
  724                         }
  725                         n->m_pkthdr.rcvif = NULL;
  726                         n->m_len = 0;
  727                         maxhlen = M_TRAILINGSPACE(n) - maxlen;
  728                         pr = curthread->td_ucred->cr_prison;
  729                         mtx_lock(&pr->pr_mtx);
  730                         hlen = strlen(pr->pr_hostname);
  731                         if (maxhlen > hlen)
  732                                 maxhlen = hlen;
  733                         /*
  734                          * Copy IPv6 and ICMPv6 only.
  735                          */
  736                         nip6 = mtod(n, struct ip6_hdr *);
  737                         bcopy(ip6, nip6, sizeof(struct ip6_hdr));
  738                         nicmp6 = (struct icmp6_hdr *)(nip6 + 1);
  739                         bcopy(icmp6, nicmp6, sizeof(struct icmp6_hdr));
  740                         p = (u_char *)(nicmp6 + 1);
  741                         bzero(p, 4);
  742                         /* meaningless TTL */
  743                         bcopy(pr->pr_hostname, p + 4, maxhlen);
  744                         mtx_unlock(&pr->pr_mtx);
  745                         noff = sizeof(struct ip6_hdr);
  746                         n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
  747                                 sizeof(struct icmp6_hdr) + 4 + maxhlen;
  748                         nicmp6->icmp6_type = ICMP6_WRUREPLY;
  749                         nicmp6->icmp6_code = 0;
  750                 }
  751                 if (n) {
  752                         ICMP6STAT_INC(icp6s_reflect);
  753                         ICMP6STAT_INC(icp6s_outhist[ICMP6_WRUREPLY]);
  754                         icmp6_reflect(n, noff);
  755                 }
  756                 break;
  757             }
  758 
  759         case ICMP6_WRUREPLY:
  760                 if (code != 0)
  761                         goto badcode;
  762                 break;
  763 
  764         case ND_ROUTER_SOLICIT:
  765                 icmp6_ifstat_inc(ifp, ifs6_in_routersolicit);
  766                 if (code != 0)
  767                         goto badcode;
  768                 if (icmp6len < sizeof(struct nd_router_solicit))
  769                         goto badlen;
  770                 if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
  771                         /* give up local */
  772 
  773                         /* Send incoming SeND packet to user space. */
  774                         if (send_sendso_input_hook != NULL) {
  775                                 IP6_EXTHDR_CHECK(m, off,
  776                                     icmp6len, IPPROTO_DONE);
  777                                 error = send_sendso_input_hook(m, ifp,
  778                                     SND_IN, ip6len);
  779                                 /* -1 == no app on SEND socket */
  780                                 if (error == 0)
  781                                         return (IPPROTO_DONE);
  782                                 nd6_rs_input(m, off, icmp6len);
  783                         } else
  784                                 nd6_rs_input(m, off, icmp6len);
  785                         m = NULL;
  786                         goto freeit;
  787                 }
  788                 if (send_sendso_input_hook != NULL) {
  789                         IP6_EXTHDR_CHECK(n, off,
  790                             icmp6len, IPPROTO_DONE);
  791                         error = send_sendso_input_hook(n, ifp,
  792                             SND_IN, ip6len);
  793                         if (error == 0)
  794                                 goto freeit;
  795                         /* -1 == no app on SEND socket */
  796                         nd6_rs_input(n, off, icmp6len);
  797                 } else
  798                         nd6_rs_input(n, off, icmp6len);
  799                 /* m stays. */
  800                 break;
  801 
  802         case ND_ROUTER_ADVERT:
  803                 icmp6_ifstat_inc(ifp, ifs6_in_routeradvert);
  804                 if (code != 0)
  805                         goto badcode;
  806                 if (icmp6len < sizeof(struct nd_router_advert))
  807                         goto badlen;
  808                 if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
  809 
  810                         /* Send incoming SeND-protected/ND packet to user space. */
  811                         if (send_sendso_input_hook != NULL) {
  812                                 error = send_sendso_input_hook(m, ifp,
  813                                     SND_IN, ip6len);
  814                                 if (error == 0)
  815                                         return (IPPROTO_DONE);
  816                                 nd6_ra_input(m, off, icmp6len);
  817                         } else
  818                                 nd6_ra_input(m, off, icmp6len);
  819                         m = NULL;
  820                         goto freeit;
  821                 }
  822                 if (send_sendso_input_hook != NULL) {
  823                         error = send_sendso_input_hook(n, ifp,
  824                             SND_IN, ip6len);
  825                         if (error == 0)
  826                                 goto freeit;
  827                         nd6_ra_input(n, off, icmp6len);
  828                 } else
  829                         nd6_ra_input(n, off, icmp6len);
  830                 /* m stays. */
  831                 break;
  832 
  833         case ND_NEIGHBOR_SOLICIT:
  834                 icmp6_ifstat_inc(ifp, ifs6_in_neighborsolicit);
  835                 if (code != 0)
  836                         goto badcode;
  837                 if (icmp6len < sizeof(struct nd_neighbor_solicit))
  838                         goto badlen;
  839                 if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
  840                         if (send_sendso_input_hook != NULL) {
  841                                 error = send_sendso_input_hook(m, ifp,
  842                                     SND_IN, ip6len);
  843                                 if (error == 0)
  844                                         return (IPPROTO_DONE);
  845                                 nd6_ns_input(m, off, icmp6len);
  846                         } else
  847                                 nd6_ns_input(m, off, icmp6len);
  848                         m = NULL;
  849                         goto freeit;
  850                 }
  851                 if (send_sendso_input_hook != NULL) {
  852                         error = send_sendso_input_hook(n, ifp,
  853                             SND_IN, ip6len);
  854                         if (error == 0)
  855                                 goto freeit;
  856                         nd6_ns_input(n, off, icmp6len);
  857                 } else
  858                         nd6_ns_input(n, off, icmp6len);
  859                 /* m stays. */
  860                 break;
  861 
  862         case ND_NEIGHBOR_ADVERT:
  863                 icmp6_ifstat_inc(ifp, ifs6_in_neighboradvert);
  864                 if (code != 0)
  865                         goto badcode;
  866                 if (icmp6len < sizeof(struct nd_neighbor_advert))
  867                         goto badlen;
  868                 if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
  869 
  870                         /* Send incoming SeND-protected/ND packet to user space. */
  871                         if (send_sendso_input_hook != NULL) {
  872                                 error = send_sendso_input_hook(m, ifp,
  873                                     SND_IN, ip6len);
  874                                 if (error == 0)
  875                                         return (IPPROTO_DONE);
  876                                 nd6_na_input(m, off, icmp6len);
  877                         } else
  878                                 nd6_na_input(m, off, icmp6len);
  879                         m = NULL;
  880                         goto freeit;
  881                 }
  882                 if (send_sendso_input_hook != NULL) {
  883                         error = send_sendso_input_hook(n, ifp,
  884                             SND_IN, ip6len);
  885                         if (error == 0)
  886                                 goto freeit;
  887                         nd6_na_input(n, off, icmp6len);
  888                 } else
  889                         nd6_na_input(n, off, icmp6len);
  890                 /* m stays. */
  891                 break;
  892 
  893         case ND_REDIRECT:
  894                 icmp6_ifstat_inc(ifp, ifs6_in_redirect);
  895                 if (code != 0)
  896                         goto badcode;
  897                 if (icmp6len < sizeof(struct nd_redirect))
  898                         goto badlen;
  899                 if ((n = m_copym(m, 0, M_COPYALL, M_DONTWAIT)) == NULL) {
  900                         if (send_sendso_input_hook != NULL) {
  901                                 error = send_sendso_input_hook(m, ifp,
  902                                     SND_IN, ip6len);
  903                                 if (error == 0)
  904                                         return (IPPROTO_DONE);
  905                             icmp6_redirect_input(m, off);
  906                         } else
  907                                 icmp6_redirect_input(m, off);
  908                         m = NULL;
  909                         goto freeit;
  910                 }
  911                 if (send_sendso_input_hook != NULL) {
  912                         error = send_sendso_input_hook(n, ifp,
  913                             SND_IN, ip6len);
  914                         if (error == 0)
  915                                 goto freeit;
  916                         icmp6_redirect_input(n, off);
  917                 } else
  918                         icmp6_redirect_input(n, off);
  919                 /* m stays. */
  920                 break;
  921 
  922         case ICMP6_ROUTER_RENUMBERING:
  923                 if (code != ICMP6_ROUTER_RENUMBERING_COMMAND &&
  924                     code != ICMP6_ROUTER_RENUMBERING_RESULT)
  925                         goto badcode;
  926                 if (icmp6len < sizeof(struct icmp6_router_renum))
  927                         goto badlen;
  928                 break;
  929 
  930         default:
  931                 nd6log((LOG_DEBUG,
  932                     "icmp6_input: unknown type %d(src=%s, dst=%s, ifid=%d)\n",
  933                     icmp6->icmp6_type, ip6_sprintf(ip6bufs, &ip6->ip6_src),
  934                     ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  935                     ifp ? ifp->if_index : 0));
  936                 if (icmp6->icmp6_type < ICMP6_ECHO_REQUEST) {
  937                         /* ICMPv6 error: MUST deliver it by spec... */
  938                         code = PRC_NCMDS;
  939                         /* deliver */
  940                 } else {
  941                         /* ICMPv6 informational: MUST not deliver */
  942                         break;
  943                 }
  944         deliver:
  945                 if (icmp6_notify_error(&m, off, icmp6len, code) != 0) {
  946                         /* In this case, m should've been freed. */
  947                         return (IPPROTO_DONE);
  948                 }
  949                 break;
  950 
  951         badcode:
  952                 ICMP6STAT_INC(icp6s_badcode);
  953                 break;
  954 
  955         badlen:
  956                 ICMP6STAT_INC(icp6s_badlen);
  957                 break;
  958         }
  959 
  960         /* deliver the packet to appropriate sockets */
  961         icmp6_rip6_input(&m, *offp);
  962 
  963         return IPPROTO_DONE;
  964 
  965  freeit:
  966         m_freem(m);
  967         return IPPROTO_DONE;
  968 }
  969 
  970 static int
  971 icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
  972 {
  973         struct mbuf *m = *mp;
  974         struct icmp6_hdr *icmp6;
  975         struct ip6_hdr *eip6;
  976         u_int32_t notifymtu;
  977         struct sockaddr_in6 icmp6src, icmp6dst;
  978 
  979         if (icmp6len < sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr)) {
  980                 ICMP6STAT_INC(icp6s_tooshort);
  981                 goto freeit;
  982         }
  983 #ifndef PULLDOWN_TEST
  984         IP6_EXTHDR_CHECK(m, off,
  985             sizeof(struct icmp6_hdr) + sizeof(struct ip6_hdr), -1);
  986         icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
  987 #else
  988         IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
  989             sizeof(*icmp6) + sizeof(struct ip6_hdr));
  990         if (icmp6 == NULL) {
  991                 ICMP6STAT_INC(icp6s_tooshort);
  992                 return (-1);
  993         }
  994 #endif
  995         eip6 = (struct ip6_hdr *)(icmp6 + 1);
  996 
  997         /* Detect the upper level protocol */
  998         {
  999                 void (*ctlfunc)(int, struct sockaddr *, void *);
 1000                 u_int8_t nxt = eip6->ip6_nxt;
 1001                 int eoff = off + sizeof(struct icmp6_hdr) +
 1002                     sizeof(struct ip6_hdr);
 1003                 struct ip6ctlparam ip6cp;
 1004                 struct in6_addr *finaldst = NULL;
 1005                 int icmp6type = icmp6->icmp6_type;
 1006                 struct ip6_frag *fh;
 1007                 struct ip6_rthdr *rth;
 1008                 struct ip6_rthdr0 *rth0;
 1009                 int rthlen;
 1010 
 1011                 while (1) { /* XXX: should avoid infinite loop explicitly? */
 1012                         struct ip6_ext *eh;
 1013 
 1014                         switch (nxt) {
 1015                         case IPPROTO_HOPOPTS:
 1016                         case IPPROTO_DSTOPTS:
 1017                         case IPPROTO_AH:
 1018 #ifndef PULLDOWN_TEST
 1019                                 IP6_EXTHDR_CHECK(m, 0,
 1020                                     eoff + sizeof(struct ip6_ext), -1);
 1021                                 eh = (struct ip6_ext *)(mtod(m, caddr_t) + eoff);
 1022 #else
 1023                                 IP6_EXTHDR_GET(eh, struct ip6_ext *, m,
 1024                                     eoff, sizeof(*eh));
 1025                                 if (eh == NULL) {
 1026                                         ICMP6STAT_INC(icp6s_tooshort);
 1027                                         return (-1);
 1028                                 }
 1029 #endif
 1030 
 1031                                 if (nxt == IPPROTO_AH)
 1032                                         eoff += (eh->ip6e_len + 2) << 2;
 1033                                 else
 1034                                         eoff += (eh->ip6e_len + 1) << 3;
 1035                                 nxt = eh->ip6e_nxt;
 1036                                 break;
 1037                         case IPPROTO_ROUTING:
 1038                                 /*
 1039                                  * When the erroneous packet contains a
 1040                                  * routing header, we should examine the
 1041                                  * header to determine the final destination.
 1042                                  * Otherwise, we can't properly update
 1043                                  * information that depends on the final
 1044                                  * destination (e.g. path MTU).
 1045                                  */
 1046 #ifndef PULLDOWN_TEST
 1047                                 IP6_EXTHDR_CHECK(m, 0, eoff + sizeof(*rth), -1);
 1048                                 rth = (struct ip6_rthdr *)
 1049                                     (mtod(m, caddr_t) + eoff);
 1050 #else
 1051                                 IP6_EXTHDR_GET(rth, struct ip6_rthdr *, m,
 1052                                     eoff, sizeof(*rth));
 1053                                 if (rth == NULL) {
 1054                                         ICMP6STAT_INC(icp6s_tooshort);
 1055                                         return (-1);
 1056                                 }
 1057 #endif
 1058                                 rthlen = (rth->ip6r_len + 1) << 3;
 1059                                 /*
 1060                                  * XXX: currently there is no
 1061                                  * officially defined type other
 1062                                  * than type-0.
 1063                                  * Note that if the segment left field
 1064                                  * is 0, all intermediate hops must
 1065                                  * have been passed.
 1066                                  */
 1067                                 if (rth->ip6r_segleft &&
 1068                                     rth->ip6r_type == IPV6_RTHDR_TYPE_0) {
 1069                                         int hops;
 1070 
 1071 #ifndef PULLDOWN_TEST
 1072                                         IP6_EXTHDR_CHECK(m, 0, eoff + rthlen, -1);
 1073                                         rth0 = (struct ip6_rthdr0 *)
 1074                                             (mtod(m, caddr_t) + eoff);
 1075 #else
 1076                                         IP6_EXTHDR_GET(rth0,
 1077                                             struct ip6_rthdr0 *, m,
 1078                                             eoff, rthlen);
 1079                                         if (rth0 == NULL) {
 1080                                                 ICMP6STAT_INC(icp6s_tooshort);
 1081                                                 return (-1);
 1082                                         }
 1083 #endif
 1084                                         /* just ignore a bogus header */
 1085                                         if ((rth0->ip6r0_len % 2) == 0 &&
 1086                                             (hops = rth0->ip6r0_len/2))
 1087                                                 finaldst = (struct in6_addr *)(rth0 + 1) + (hops - 1);
 1088                                 }
 1089                                 eoff += rthlen;
 1090                                 nxt = rth->ip6r_nxt;
 1091                                 break;
 1092                         case IPPROTO_FRAGMENT:
 1093 #ifndef PULLDOWN_TEST
 1094                                 IP6_EXTHDR_CHECK(m, 0, eoff +
 1095                                     sizeof(struct ip6_frag), -1);
 1096                                 fh = (struct ip6_frag *)(mtod(m, caddr_t) +
 1097                                     eoff);
 1098 #else
 1099                                 IP6_EXTHDR_GET(fh, struct ip6_frag *, m,
 1100                                     eoff, sizeof(*fh));
 1101                                 if (fh == NULL) {
 1102                                         ICMP6STAT_INC(icp6s_tooshort);
 1103                                         return (-1);
 1104                                 }
 1105 #endif
 1106                                 /*
 1107                                  * Data after a fragment header is meaningless
 1108                                  * unless it is the first fragment, but
 1109                                  * we'll go to the notify label for path MTU
 1110                                  * discovery.
 1111                                  */
 1112                                 if (fh->ip6f_offlg & IP6F_OFF_MASK)
 1113                                         goto notify;
 1114 
 1115                                 eoff += sizeof(struct ip6_frag);
 1116                                 nxt = fh->ip6f_nxt;
 1117                                 break;
 1118                         default:
 1119                                 /*
 1120                                  * This case includes ESP and the No Next
 1121                                  * Header.  In such cases going to the notify
 1122                                  * label does not have any meaning
 1123                                  * (i.e. ctlfunc will be NULL), but we go
 1124                                  * anyway since we might have to update
 1125                                  * path MTU information.
 1126                                  */
 1127                                 goto notify;
 1128                         }
 1129                 }
 1130           notify:
 1131 #ifndef PULLDOWN_TEST
 1132                 icmp6 = (struct icmp6_hdr *)(mtod(m, caddr_t) + off);
 1133 #else
 1134                 IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off,
 1135                     sizeof(*icmp6) + sizeof(struct ip6_hdr));
 1136                 if (icmp6 == NULL) {
 1137                         ICMP6STAT_INC(icp6s_tooshort);
 1138                         return (-1);
 1139                 }
 1140 #endif
 1141 
 1142                 /*
 1143                  * retrieve parameters from the inner IPv6 header, and convert
 1144                  * them into sockaddr structures.
 1145                  * XXX: there is no guarantee that the source or destination
 1146                  * addresses of the inner packet are in the same scope as
 1147                  * the addresses of the icmp packet.  But there is no other
 1148                  * way to determine the zone.
 1149                  */
 1150                 eip6 = (struct ip6_hdr *)(icmp6 + 1);
 1151 
 1152                 bzero(&icmp6dst, sizeof(icmp6dst));
 1153                 icmp6dst.sin6_len = sizeof(struct sockaddr_in6);
 1154                 icmp6dst.sin6_family = AF_INET6;
 1155                 if (finaldst == NULL)
 1156                         icmp6dst.sin6_addr = eip6->ip6_dst;
 1157                 else
 1158                         icmp6dst.sin6_addr = *finaldst;
 1159                 if (in6_setscope(&icmp6dst.sin6_addr, m->m_pkthdr.rcvif, NULL))
 1160                         goto freeit;
 1161                 bzero(&icmp6src, sizeof(icmp6src));
 1162                 icmp6src.sin6_len = sizeof(struct sockaddr_in6);
 1163                 icmp6src.sin6_family = AF_INET6;
 1164                 icmp6src.sin6_addr = eip6->ip6_src;
 1165                 if (in6_setscope(&icmp6src.sin6_addr, m->m_pkthdr.rcvif, NULL))
 1166                         goto freeit;
 1167                 icmp6src.sin6_flowinfo =
 1168                     (eip6->ip6_flow & IPV6_FLOWLABEL_MASK);
 1169 
 1170                 if (finaldst == NULL)
 1171                         finaldst = &eip6->ip6_dst;
 1172                 ip6cp.ip6c_m = m;
 1173                 ip6cp.ip6c_icmp6 = icmp6;
 1174                 ip6cp.ip6c_ip6 = (struct ip6_hdr *)(icmp6 + 1);
 1175                 ip6cp.ip6c_off = eoff;
 1176                 ip6cp.ip6c_finaldst = finaldst;
 1177                 ip6cp.ip6c_src = &icmp6src;
 1178                 ip6cp.ip6c_nxt = nxt;
 1179 
 1180                 m_addr_changed(m);
 1181 
 1182                 if (icmp6type == ICMP6_PACKET_TOO_BIG) {
 1183                         notifymtu = ntohl(icmp6->icmp6_mtu);
 1184                         ip6cp.ip6c_cmdarg = (void *)&notifymtu;
 1185                         icmp6_mtudisc_update(&ip6cp, 1);        /*XXX*/
 1186                 }
 1187 
 1188                 ctlfunc = (void (*)(int, struct sockaddr *, void *))
 1189                     (inet6sw[ip6_protox[nxt]].pr_ctlinput);
 1190                 if (ctlfunc) {
 1191                         (void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
 1192                             &ip6cp);
 1193                 }
 1194         }
 1195         *mp = m;
 1196         return (0);
 1197 
 1198   freeit:
 1199         m_freem(m);
 1200         return (-1);
 1201 }
 1202 
 1203 void
 1204 icmp6_mtudisc_update(struct ip6ctlparam *ip6cp, int validated)
 1205 {
 1206         struct in6_addr *dst = ip6cp->ip6c_finaldst;
 1207         struct icmp6_hdr *icmp6 = ip6cp->ip6c_icmp6;
 1208         struct mbuf *m = ip6cp->ip6c_m; /* will be necessary for scope issue */
 1209         u_int mtu = ntohl(icmp6->icmp6_mtu);
 1210         struct in_conninfo inc;
 1211 
 1212 #if 0
 1213         /*
 1214          * RFC2460 section 5, last paragraph.
 1215          * even though minimum link MTU for IPv6 is IPV6_MMTU,
 1216          * we may see ICMPv6 too big with mtu < IPV6_MMTU
 1217          * due to packet translator in the middle.
 1218          * see ip6_output() and ip6_getpmtu() "alwaysfrag" case for
 1219          * special handling.
 1220          */
 1221         if (mtu < IPV6_MMTU)
 1222                 return;
 1223 #endif
 1224 
 1225         /*
 1226          * we reject ICMPv6 too big with abnormally small value.
 1227          * XXX what is the good definition of "abnormally small"?
 1228          */
 1229         if (mtu < sizeof(struct ip6_hdr) + sizeof(struct ip6_frag) + 8)
 1230                 return;
 1231 
 1232         if (!validated)
 1233                 return;
 1234 
 1235         /*
 1236          * In case the suggested mtu is less than IPV6_MMTU, we
 1237          * only need to remember that it was for above mentioned
 1238          * "alwaysfrag" case.
 1239          * Try to be as close to the spec as possible.
 1240          */
 1241         if (mtu < IPV6_MMTU)
 1242                 mtu = IPV6_MMTU - 8;
 1243 
 1244         bzero(&inc, sizeof(inc));
 1245         inc.inc_flags |= INC_ISIPV6;
 1246         inc.inc6_faddr = *dst;
 1247         if (in6_setscope(&inc.inc6_faddr, m->m_pkthdr.rcvif, NULL))
 1248                 return;
 1249 
 1250         if (mtu < tcp_maxmtu6(&inc, NULL)) {
 1251                 tcp_hc_updatemtu(&inc, mtu);
 1252                 ICMP6STAT_INC(icp6s_pmtuchg);
 1253         }
 1254 }
 1255 
 1256 /*
 1257  * Process a Node Information Query packet, based on
 1258  * draft-ietf-ipngwg-icmp-name-lookups-07.
 1259  *
 1260  * Spec incompatibilities:
 1261  * - IPv6 Subject address handling
 1262  * - IPv4 Subject address handling support missing
 1263  * - Proxy reply (answer even if it's not for me)
 1264  * - joins NI group address at in6_ifattach() time only, does not cope
 1265  *   with hostname changes by sethostname(3)
 1266  */
 1267 static struct mbuf *
 1268 ni6_input(struct mbuf *m, int off)
 1269 {
 1270         struct icmp6_nodeinfo *ni6, *nni6;
 1271         struct mbuf *n = NULL;
 1272         struct prison *pr;
 1273         u_int16_t qtype;
 1274         int subjlen;
 1275         int replylen = sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
 1276         struct ni_reply_fqdn *fqdn;
 1277         int addrs;              /* for NI_QTYPE_NODEADDR */
 1278         struct ifnet *ifp = NULL; /* for NI_QTYPE_NODEADDR */
 1279         struct in6_addr in6_subj; /* subject address */
 1280         struct ip6_hdr *ip6;
 1281         int oldfqdn = 0;        /* if 1, return pascal string (03 draft) */
 1282         char *subj = NULL;
 1283         struct in6_ifaddr *ia6 = NULL;
 1284 
 1285         ip6 = mtod(m, struct ip6_hdr *);
 1286 #ifndef PULLDOWN_TEST
 1287         ni6 = (struct icmp6_nodeinfo *)(mtod(m, caddr_t) + off);
 1288 #else
 1289         IP6_EXTHDR_GET(ni6, struct icmp6_nodeinfo *, m, off, sizeof(*ni6));
 1290         if (ni6 == NULL) {
 1291                 /* m is already reclaimed */
 1292                 return (NULL);
 1293         }
 1294 #endif
 1295 
 1296         /*
 1297          * Validate IPv6 source address.
 1298          * The default configuration MUST be to refuse answering queries from
 1299          * global-scope addresses according to RFC4602.
 1300          * Notes:
 1301          *  - it's not very clear what "refuse" means; this implementation
 1302          *    simply drops it.
 1303          *  - it's not very easy to identify global-scope (unicast) addresses
 1304          *    since there are many prefixes for them.  It should be safer
 1305          *    and in practice sufficient to check "all" but loopback and
 1306          *    link-local (note that site-local unicast was deprecated and
 1307          *    ULA is defined as global scope-wise)
 1308          */
 1309         if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_GLOBALOK) == 0 &&
 1310             !IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) &&
 1311             !IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src))
 1312                 goto bad;
 1313 
 1314         /*
 1315          * Validate IPv6 destination address.
 1316          *
 1317          * The Responder must discard the Query without further processing
 1318          * unless it is one of the Responder's unicast or anycast addresses, or
 1319          * a link-local scope multicast address which the Responder has joined.
 1320          * [RFC4602, Section 5.]
 1321          */
 1322         if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
 1323                 if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
 1324                         goto bad;
 1325                 /* else it's a link-local multicast, fine */
 1326         } else {                /* unicast or anycast */
 1327                 if ((ia6 = ip6_getdstifaddr(m)) == NULL)
 1328                         goto bad; /* XXX impossible */
 1329 
 1330                 if ((ia6->ia6_flags & IN6_IFF_TEMPORARY) &&
 1331                     !(V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK)) {
 1332                         ifa_free(&ia6->ia_ifa);
 1333                         nd6log((LOG_DEBUG, "ni6_input: ignore node info to "
 1334                                 "a temporary address in %s:%d",
 1335                                __FILE__, __LINE__));
 1336                         goto bad;
 1337                 }
 1338                 ifa_free(&ia6->ia_ifa);
 1339         }
 1340 
 1341         /* validate query Subject field. */
 1342         qtype = ntohs(ni6->ni_qtype);
 1343         subjlen = m->m_pkthdr.len - off - sizeof(struct icmp6_nodeinfo);
 1344         switch (qtype) {
 1345         case NI_QTYPE_NOOP:
 1346         case NI_QTYPE_SUPTYPES:
 1347                 /* 07 draft */
 1348                 if (ni6->ni_code == ICMP6_NI_SUBJ_FQDN && subjlen == 0)
 1349                         break;
 1350                 /* FALLTHROUGH */
 1351         case NI_QTYPE_FQDN:
 1352         case NI_QTYPE_NODEADDR:
 1353         case NI_QTYPE_IPV4ADDR:
 1354                 switch (ni6->ni_code) {
 1355                 case ICMP6_NI_SUBJ_IPV6:
 1356 #if ICMP6_NI_SUBJ_IPV6 != 0
 1357                 case 0:
 1358 #endif
 1359                         /*
 1360                          * backward compatibility - try to accept 03 draft
 1361                          * format, where no Subject is present.
 1362                          */
 1363                         if (qtype == NI_QTYPE_FQDN && ni6->ni_code == 0 &&
 1364                             subjlen == 0) {
 1365                                 oldfqdn++;
 1366                                 break;
 1367                         }
 1368 #if ICMP6_NI_SUBJ_IPV6 != 0
 1369                         if (ni6->ni_code != ICMP6_NI_SUBJ_IPV6)
 1370                                 goto bad;
 1371 #endif
 1372 
 1373                         if (subjlen != sizeof(struct in6_addr))
 1374                                 goto bad;
 1375 
 1376                         /*
 1377                          * Validate Subject address.
 1378                          *
 1379                          * Not sure what exactly "address belongs to the node"
 1380                          * means in the spec, is it just unicast, or what?
 1381                          *
 1382                          * At this moment we consider Subject address as
 1383                          * "belong to the node" if the Subject address equals
 1384                          * to the IPv6 destination address; validation for
 1385                          * IPv6 destination address should have done enough
 1386                          * check for us.
 1387                          *
 1388                          * We do not do proxy at this moment.
 1389                          */
 1390                         /* m_pulldown instead of copy? */
 1391                         m_copydata(m, off + sizeof(struct icmp6_nodeinfo),
 1392                             subjlen, (caddr_t)&in6_subj);
 1393                         if (in6_setscope(&in6_subj, m->m_pkthdr.rcvif, NULL))
 1394                                 goto bad;
 1395 
 1396                         subj = (char *)&in6_subj;
 1397                         if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &in6_subj))
 1398                                 break;
 1399 
 1400                         /*
 1401                          * XXX if we are to allow other cases, we should really
 1402                          * be careful about scope here.
 1403                          * basically, we should disallow queries toward IPv6
 1404                          * destination X with subject Y,
 1405                          * if scope(X) > scope(Y).
 1406                          * if we allow scope(X) > scope(Y), it will result in
 1407                          * information leakage across scope boundary.
 1408                          */
 1409                         goto bad;
 1410 
 1411                 case ICMP6_NI_SUBJ_FQDN:
 1412                         /*
 1413                          * Validate Subject name with gethostname(3).
 1414                          *
 1415                          * The behavior may need some debate, since:
 1416                          * - we are not sure if the node has FQDN as
 1417                          *   hostname (returned by gethostname(3)).
 1418                          * - the code does wildcard match for truncated names.
 1419                          *   however, we are not sure if we want to perform
 1420                          *   wildcard match, if gethostname(3) side has
 1421                          *   truncated hostname.
 1422                          */
 1423                         pr = curthread->td_ucred->cr_prison;
 1424                         mtx_lock(&pr->pr_mtx);
 1425                         n = ni6_nametodns(pr->pr_hostname,
 1426                             strlen(pr->pr_hostname), 0);
 1427                         mtx_unlock(&pr->pr_mtx);
 1428                         if (!n || n->m_next || n->m_len == 0)
 1429                                 goto bad;
 1430                         IP6_EXTHDR_GET(subj, char *, m,
 1431                             off + sizeof(struct icmp6_nodeinfo), subjlen);
 1432                         if (subj == NULL)
 1433                                 goto bad;
 1434                         if (!ni6_dnsmatch(subj, subjlen, mtod(n, const char *),
 1435                             n->m_len)) {
 1436                                 goto bad;
 1437                         }
 1438                         m_freem(n);
 1439                         n = NULL;
 1440                         break;
 1441 
 1442                 case ICMP6_NI_SUBJ_IPV4:        /* XXX: to be implemented? */
 1443                 default:
 1444                         goto bad;
 1445                 }
 1446                 break;
 1447         }
 1448 
 1449         /* refuse based on configuration.  XXX ICMP6_NI_REFUSED? */
 1450         switch (qtype) {
 1451         case NI_QTYPE_FQDN:
 1452                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_FQDNOK) == 0)
 1453                         goto bad;
 1454                 break;
 1455         case NI_QTYPE_NODEADDR:
 1456         case NI_QTYPE_IPV4ADDR:
 1457                 if ((V_icmp6_nodeinfo & ICMP6_NODEINFO_NODEADDROK) == 0)
 1458                         goto bad;
 1459                 break;
 1460         }
 1461 
 1462         /* guess reply length */
 1463         switch (qtype) {
 1464         case NI_QTYPE_NOOP:
 1465                 break;          /* no reply data */
 1466         case NI_QTYPE_SUPTYPES:
 1467                 replylen += sizeof(u_int32_t);
 1468                 break;
 1469         case NI_QTYPE_FQDN:
 1470                 /* XXX will append an mbuf */
 1471                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
 1472                 break;
 1473         case NI_QTYPE_NODEADDR:
 1474                 addrs = ni6_addrs(ni6, m, &ifp, (struct in6_addr *)subj);
 1475                 if ((replylen += addrs * (sizeof(struct in6_addr) +
 1476                     sizeof(u_int32_t))) > MCLBYTES)
 1477                         replylen = MCLBYTES; /* XXX: will truncate pkt later */
 1478                 break;
 1479         case NI_QTYPE_IPV4ADDR:
 1480                 /* unsupported - should respond with unknown Qtype? */
 1481                 break;
 1482         default:
 1483                 /*
 1484                  * XXX: We must return a reply with the ICMP6 code
 1485                  * `unknown Qtype' in this case.  However we regard the case
 1486                  * as an FQDN query for backward compatibility.
 1487                  * Older versions set a random value to this field,
 1488                  * so it rarely varies in the defined qtypes.
 1489                  * But the mechanism is not reliable...
 1490                  * maybe we should obsolete older versions.
 1491                  */
 1492                 qtype = NI_QTYPE_FQDN;
 1493                 /* XXX will append an mbuf */
 1494                 replylen += offsetof(struct ni_reply_fqdn, ni_fqdn_namelen);
 1495                 oldfqdn++;
 1496                 break;
 1497         }
 1498 
 1499         /* allocate an mbuf to reply. */
 1500         MGETHDR(n, M_DONTWAIT, m->m_type);
 1501         if (n == NULL) {
 1502                 m_freem(m);
 1503                 return (NULL);
 1504         }
 1505         M_MOVE_PKTHDR(n, m); /* just for recvif and FIB */
 1506         if (replylen > MHLEN) {
 1507                 if (replylen > MCLBYTES) {
 1508                         /*
 1509                          * XXX: should we try to allocate more? But MCLBYTES
 1510                          * is probably much larger than IPV6_MMTU...
 1511                          */
 1512                         goto bad;
 1513                 }
 1514                 MCLGET(n, M_DONTWAIT);
 1515                 if ((n->m_flags & M_EXT) == 0) {
 1516                         goto bad;
 1517                 }
 1518         }
 1519         n->m_pkthdr.len = n->m_len = replylen;
 1520 
 1521         /* copy mbuf header and IPv6 + Node Information base headers */
 1522         bcopy(mtod(m, caddr_t), mtod(n, caddr_t), sizeof(struct ip6_hdr));
 1523         nni6 = (struct icmp6_nodeinfo *)(mtod(n, struct ip6_hdr *) + 1);
 1524         bcopy((caddr_t)ni6, (caddr_t)nni6, sizeof(struct icmp6_nodeinfo));
 1525 
 1526         /* qtype dependent procedure */
 1527         switch (qtype) {
 1528         case NI_QTYPE_NOOP:
 1529                 nni6->ni_code = ICMP6_NI_SUCCESS;
 1530                 nni6->ni_flags = 0;
 1531                 break;
 1532         case NI_QTYPE_SUPTYPES:
 1533         {
 1534                 u_int32_t v;
 1535                 nni6->ni_code = ICMP6_NI_SUCCESS;
 1536                 nni6->ni_flags = htons(0x0000); /* raw bitmap */
 1537                 /* supports NOOP, SUPTYPES, FQDN, and NODEADDR */
 1538                 v = (u_int32_t)htonl(0x0000000f);
 1539                 bcopy(&v, nni6 + 1, sizeof(u_int32_t));
 1540                 break;
 1541         }
 1542         case NI_QTYPE_FQDN:
 1543                 nni6->ni_code = ICMP6_NI_SUCCESS;
 1544                 fqdn = (struct ni_reply_fqdn *)(mtod(n, caddr_t) +
 1545                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo));
 1546                 nni6->ni_flags = 0; /* XXX: meaningless TTL */
 1547                 fqdn->ni_fqdn_ttl = 0;  /* ditto. */
 1548                 /*
 1549                  * XXX do we really have FQDN in hostname?
 1550                  */
 1551                 pr = curthread->td_ucred->cr_prison;
 1552                 mtx_lock(&pr->pr_mtx);
 1553                 n->m_next = ni6_nametodns(pr->pr_hostname,
 1554                     strlen(pr->pr_hostname), oldfqdn);
 1555                 mtx_unlock(&pr->pr_mtx);
 1556                 if (n->m_next == NULL)
 1557                         goto bad;
 1558                 /* XXX we assume that n->m_next is not a chain */
 1559                 if (n->m_next->m_next != NULL)
 1560                         goto bad;
 1561                 n->m_pkthdr.len += n->m_next->m_len;
 1562                 break;
 1563         case NI_QTYPE_NODEADDR:
 1564         {
 1565                 int lenlim, copied;
 1566 
 1567                 nni6->ni_code = ICMP6_NI_SUCCESS;
 1568                 n->m_pkthdr.len = n->m_len =
 1569                     sizeof(struct ip6_hdr) + sizeof(struct icmp6_nodeinfo);
 1570                 lenlim = M_TRAILINGSPACE(n);
 1571                 copied = ni6_store_addrs(ni6, nni6, ifp, lenlim);
 1572                 /* XXX: reset mbuf length */
 1573                 n->m_pkthdr.len = n->m_len = sizeof(struct ip6_hdr) +
 1574                     sizeof(struct icmp6_nodeinfo) + copied;
 1575                 break;
 1576         }
 1577         default:
 1578                 break;          /* XXX impossible! */
 1579         }
 1580 
 1581         nni6->ni_type = ICMP6_NI_REPLY;
 1582         m_freem(m);
 1583         return (n);
 1584 
 1585   bad:
 1586         m_freem(m);
 1587         if (n)
 1588                 m_freem(n);
 1589         return (NULL);
 1590 }
 1591 
 1592 /*
 1593  * make a mbuf with DNS-encoded string.  no compression support.
 1594  *
 1595  * XXX names with less than 2 dots (like "foo" or "foo.section") will be
 1596  * treated as truncated name (two \0 at the end).  this is a wild guess.
 1597  *
 1598  * old - return pascal string if non-zero
 1599  */
 1600 static struct mbuf *
 1601 ni6_nametodns(const char *name, int namelen, int old)
 1602 {
 1603         struct mbuf *m;
 1604         char *cp, *ep;
 1605         const char *p, *q;
 1606         int i, len, nterm;
 1607 
 1608         if (old)
 1609                 len = namelen + 1;
 1610         else
 1611                 len = MCLBYTES;
 1612 
 1613         /* because MAXHOSTNAMELEN is usually 256, we use cluster mbuf */
 1614         MGET(m, M_DONTWAIT, MT_DATA);
 1615         if (m && len > MLEN) {
 1616                 MCLGET(m, M_DONTWAIT);
 1617                 if ((m->m_flags & M_EXT) == 0)
 1618                         goto fail;
 1619         }
 1620         if (!m)
 1621                 goto fail;
 1622         m->m_next = NULL;
 1623 
 1624         if (old) {
 1625                 m->m_len = len;
 1626                 *mtod(m, char *) = namelen;
 1627                 bcopy(name, mtod(m, char *) + 1, namelen);
 1628                 return m;
 1629         } else {
 1630                 m->m_len = 0;
 1631                 cp = mtod(m, char *);
 1632                 ep = mtod(m, char *) + M_TRAILINGSPACE(m);
 1633 
 1634                 /* if not certain about my name, return empty buffer */
 1635                 if (namelen == 0)
 1636                         return m;
 1637 
 1638                 /*
 1639                  * guess if it looks like shortened hostname, or FQDN.
 1640                  * shortened hostname needs two trailing "\0".
 1641                  */
 1642                 i = 0;
 1643                 for (p = name; p < name + namelen; p++) {
 1644                         if (*p && *p == '.')
 1645                                 i++;
 1646                 }
 1647                 if (i < 2)
 1648                         nterm = 2;
 1649                 else
 1650                         nterm = 1;
 1651 
 1652                 p = name;
 1653                 while (cp < ep && p < name + namelen) {
 1654                         i = 0;
 1655                         for (q = p; q < name + namelen && *q && *q != '.'; q++)
 1656                                 i++;
 1657                         /* result does not fit into mbuf */
 1658                         if (cp + i + 1 >= ep)
 1659                                 goto fail;
 1660                         /*
 1661                          * DNS label length restriction, RFC1035 page 8.
 1662                          * "i == 0" case is included here to avoid returning
 1663                          * 0-length label on "foo..bar".
 1664                          */
 1665                         if (i <= 0 || i >= 64)
 1666                                 goto fail;
 1667                         *cp++ = i;
 1668                         bcopy(p, cp, i);
 1669                         cp += i;
 1670                         p = q;
 1671                         if (p < name + namelen && *p == '.')
 1672                                 p++;
 1673                 }
 1674                 /* termination */
 1675                 if (cp + nterm >= ep)
 1676                         goto fail;
 1677                 while (nterm-- > 0)
 1678                         *cp++ = '\0';
 1679                 m->m_len = cp - mtod(m, char *);
 1680                 return m;
 1681         }
 1682 
 1683         panic("should not reach here");
 1684         /* NOTREACHED */
 1685 
 1686  fail:
 1687         if (m)
 1688                 m_freem(m);
 1689         return NULL;
 1690 }
 1691 
 1692 /*
 1693  * check if two DNS-encoded string matches.  takes care of truncated
 1694  * form (with \0\0 at the end).  no compression support.
 1695  * XXX upper/lowercase match (see RFC2065)
 1696  */
 1697 static int
 1698 ni6_dnsmatch(const char *a, int alen, const char *b, int blen)
 1699 {
 1700         const char *a0, *b0;
 1701         int l;
 1702 
 1703         /* simplest case - need validation? */
 1704         if (alen == blen && bcmp(a, b, alen) == 0)
 1705                 return 1;
 1706 
 1707         a0 = a;
 1708         b0 = b;
 1709 
 1710         /* termination is mandatory */
 1711         if (alen < 2 || blen < 2)
 1712                 return 0;
 1713         if (a0[alen - 1] != '\0' || b0[blen - 1] != '\0')
 1714                 return 0;
 1715         alen--;
 1716         blen--;
 1717 
 1718         while (a - a0 < alen && b - b0 < blen) {
 1719                 if (a - a0 + 1 > alen || b - b0 + 1 > blen)
 1720                         return 0;
 1721 
 1722                 if ((signed char)a[0] < 0 || (signed char)b[0] < 0)
 1723                         return 0;
 1724                 /* we don't support compression yet */
 1725                 if (a[0] >= 64 || b[0] >= 64)
 1726                         return 0;
 1727 
 1728                 /* truncated case */
 1729                 if (a[0] == 0 && a - a0 == alen - 1)
 1730                         return 1;
 1731                 if (b[0] == 0 && b - b0 == blen - 1)
 1732                         return 1;
 1733                 if (a[0] == 0 || b[0] == 0)
 1734                         return 0;
 1735 
 1736                 if (a[0] != b[0])
 1737                         return 0;
 1738                 l = a[0];
 1739                 if (a - a0 + 1 + l > alen || b - b0 + 1 + l > blen)
 1740                         return 0;
 1741                 if (bcmp(a + 1, b + 1, l) != 0)
 1742                         return 0;
 1743 
 1744                 a += 1 + l;
 1745                 b += 1 + l;
 1746         }
 1747 
 1748         if (a - a0 == alen && b - b0 == blen)
 1749                 return 1;
 1750         else
 1751                 return 0;
 1752 }
 1753 
 1754 /*
 1755  * calculate the number of addresses to be returned in the node info reply.
 1756  */
 1757 static int
 1758 ni6_addrs(struct icmp6_nodeinfo *ni6, struct mbuf *m, struct ifnet **ifpp,
 1759     struct in6_addr *subj)
 1760 {
 1761         struct ifnet *ifp;
 1762         struct in6_ifaddr *ifa6;
 1763         struct ifaddr *ifa;
 1764         int addrs = 0, addrsofif, iffound = 0;
 1765         int niflags = ni6->ni_flags;
 1766 
 1767         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0) {
 1768                 switch (ni6->ni_code) {
 1769                 case ICMP6_NI_SUBJ_IPV6:
 1770                         if (subj == NULL) /* must be impossible... */
 1771                                 return (0);
 1772                         break;
 1773                 default:
 1774                         /*
 1775                          * XXX: we only support IPv6 subject address for
 1776                          * this Qtype.
 1777                          */
 1778                         return (0);
 1779                 }
 1780         }
 1781 
 1782         IFNET_RLOCK_NOSLEEP();
 1783         TAILQ_FOREACH(ifp, &V_ifnet, if_list) {
 1784                 addrsofif = 0;
 1785                 IF_ADDR_RLOCK(ifp);
 1786                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 1787                         if (ifa->ifa_addr->sa_family != AF_INET6)
 1788                                 continue;
 1789                         ifa6 = (struct in6_ifaddr *)ifa;
 1790 
 1791                         if ((niflags & NI_NODEADDR_FLAG_ALL) == 0 &&
 1792                             IN6_ARE_ADDR_EQUAL(subj, &ifa6->ia_addr.sin6_addr))
 1793                                 iffound = 1;
 1794 
 1795                         /*
 1796                          * IPv4-mapped addresses can only be returned by a
 1797                          * Node Information proxy, since they represent
 1798                          * addresses of IPv4-only nodes, which perforce do
 1799                          * not implement this protocol.
 1800                          * [icmp-name-lookups-07, Section 5.4]
 1801                          * So we don't support NI_NODEADDR_FLAG_COMPAT in
 1802                          * this function at this moment.
 1803                          */
 1804 
 1805                         /* What do we have to do about ::1? */
 1806                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
 1807                         case IPV6_ADDR_SCOPE_LINKLOCAL:
 1808                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
 1809                                         continue;
 1810                                 break;
 1811                         case IPV6_ADDR_SCOPE_SITELOCAL:
 1812                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
 1813                                         continue;
 1814                                 break;
 1815                         case IPV6_ADDR_SCOPE_GLOBAL:
 1816                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
 1817                                         continue;
 1818                                 break;
 1819                         default:
 1820                                 continue;
 1821                         }
 1822 
 1823                         /*
 1824                          * check if anycast is okay.
 1825                          * XXX: just experimental.  not in the spec.
 1826                          */
 1827                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
 1828                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
 1829                                 continue; /* we need only unicast addresses */
 1830                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
 1831                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
 1832                                 continue;
 1833                         }
 1834                         addrsofif++; /* count the address */
 1835                 }
 1836                 IF_ADDR_RUNLOCK(ifp);
 1837                 if (iffound) {
 1838                         *ifpp = ifp;
 1839                         IFNET_RUNLOCK_NOSLEEP();
 1840                         return (addrsofif);
 1841                 }
 1842 
 1843                 addrs += addrsofif;
 1844         }
 1845         IFNET_RUNLOCK_NOSLEEP();
 1846 
 1847         return (addrs);
 1848 }
 1849 
 1850 static int
 1851 ni6_store_addrs(struct icmp6_nodeinfo *ni6, struct icmp6_nodeinfo *nni6,
 1852     struct ifnet *ifp0, int resid)
 1853 {
 1854         struct ifnet *ifp;
 1855         struct in6_ifaddr *ifa6;
 1856         struct ifaddr *ifa;
 1857         struct ifnet *ifp_dep = NULL;
 1858         int copied = 0, allow_deprecated = 0;
 1859         u_char *cp = (u_char *)(nni6 + 1);
 1860         int niflags = ni6->ni_flags;
 1861         u_int32_t ltime;
 1862 
 1863         if (ifp0 == NULL && !(niflags & NI_NODEADDR_FLAG_ALL))
 1864                 return (0);     /* needless to copy */
 1865 
 1866         IFNET_RLOCK_NOSLEEP();
 1867         ifp = ifp0 ? ifp0 : TAILQ_FIRST(&V_ifnet);
 1868   again:
 1869 
 1870         for (; ifp; ifp = TAILQ_NEXT(ifp, if_list)) {
 1871                 IF_ADDR_RLOCK(ifp);
 1872                 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 1873                         if (ifa->ifa_addr->sa_family != AF_INET6)
 1874                                 continue;
 1875                         ifa6 = (struct in6_ifaddr *)ifa;
 1876 
 1877                         if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) != 0 &&
 1878                             allow_deprecated == 0) {
 1879                                 /*
 1880                                  * prefererred address should be put before
 1881                                  * deprecated addresses.
 1882                                  */
 1883 
 1884                                 /* record the interface for later search */
 1885                                 if (ifp_dep == NULL)
 1886                                         ifp_dep = ifp;
 1887 
 1888                                 continue;
 1889                         } else if ((ifa6->ia6_flags & IN6_IFF_DEPRECATED) == 0 &&
 1890                             allow_deprecated != 0)
 1891                                 continue; /* we now collect deprecated addrs */
 1892 
 1893                         /* What do we have to do about ::1? */
 1894                         switch (in6_addrscope(&ifa6->ia_addr.sin6_addr)) {
 1895                         case IPV6_ADDR_SCOPE_LINKLOCAL:
 1896                                 if ((niflags & NI_NODEADDR_FLAG_LINKLOCAL) == 0)
 1897                                         continue;
 1898                                 break;
 1899                         case IPV6_ADDR_SCOPE_SITELOCAL:
 1900                                 if ((niflags & NI_NODEADDR_FLAG_SITELOCAL) == 0)
 1901                                         continue;
 1902                                 break;
 1903                         case IPV6_ADDR_SCOPE_GLOBAL:
 1904                                 if ((niflags & NI_NODEADDR_FLAG_GLOBAL) == 0)
 1905                                         continue;
 1906                                 break;
 1907                         default:
 1908                                 continue;
 1909                         }
 1910 
 1911                         /*
 1912                          * check if anycast is okay.
 1913                          * XXX: just experimental.  not in the spec.
 1914                          */
 1915                         if ((ifa6->ia6_flags & IN6_IFF_ANYCAST) != 0 &&
 1916                             (niflags & NI_NODEADDR_FLAG_ANYCAST) == 0)
 1917                                 continue;
 1918                         if ((ifa6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
 1919                             (V_icmp6_nodeinfo & ICMP6_NODEINFO_TMPADDROK) == 0) {
 1920                                 continue;
 1921                         }
 1922 
 1923                         /* now we can copy the address */
 1924                         if (resid < sizeof(struct in6_addr) +
 1925                             sizeof(u_int32_t)) {
 1926                                 IF_ADDR_RUNLOCK(ifp);
 1927                                 /*
 1928                                  * We give up much more copy.
 1929                                  * Set the truncate flag and return.
 1930                                  */
 1931                                 nni6->ni_flags |= NI_NODEADDR_FLAG_TRUNCATE;
 1932                                 IFNET_RUNLOCK_NOSLEEP();
 1933                                 return (copied);
 1934                         }
 1935 
 1936                         /*
 1937                          * Set the TTL of the address.
 1938                          * The TTL value should be one of the following
 1939                          * according to the specification:
 1940                          *
 1941                          * 1. The remaining lifetime of a DHCP lease on the
 1942                          *    address, or
 1943                          * 2. The remaining Valid Lifetime of a prefix from
 1944                          *    which the address was derived through Stateless
 1945                          *    Autoconfiguration.
 1946                          *
 1947                          * Note that we currently do not support stateful
 1948                          * address configuration by DHCPv6, so the former
 1949                          * case can't happen.
 1950                          */
 1951                         if (ifa6->ia6_lifetime.ia6t_expire == 0)
 1952                                 ltime = ND6_INFINITE_LIFETIME;
 1953                         else {
 1954                                 if (ifa6->ia6_lifetime.ia6t_expire >
 1955                                     time_second)
 1956                                         ltime = htonl(ifa6->ia6_lifetime.ia6t_expire - time_second);
 1957                                 else
 1958                                         ltime = 0;
 1959                         }
 1960 
 1961                         bcopy(&ltime, cp, sizeof(u_int32_t));
 1962                         cp += sizeof(u_int32_t);
 1963 
 1964                         /* copy the address itself */
 1965                         bcopy(&ifa6->ia_addr.sin6_addr, cp,
 1966                             sizeof(struct in6_addr));
 1967                         in6_clearscope((struct in6_addr *)cp); /* XXX */
 1968                         cp += sizeof(struct in6_addr);
 1969 
 1970                         resid -= (sizeof(struct in6_addr) + sizeof(u_int32_t));
 1971                         copied += (sizeof(struct in6_addr) + sizeof(u_int32_t));
 1972                 }
 1973                 IF_ADDR_RUNLOCK(ifp);
 1974                 if (ifp0)       /* we need search only on the specified IF */
 1975                         break;
 1976         }
 1977 
 1978         if (allow_deprecated == 0 && ifp_dep != NULL) {
 1979                 ifp = ifp_dep;
 1980                 allow_deprecated = 1;
 1981 
 1982                 goto again;
 1983         }
 1984 
 1985         IFNET_RUNLOCK_NOSLEEP();
 1986 
 1987         return (copied);
 1988 }
 1989 
 1990 /*
 1991  * XXX almost dup'ed code with rip6_input.
 1992  */
 1993 static int
 1994 icmp6_rip6_input(struct mbuf **mp, int off)
 1995 {
 1996         struct mbuf *m = *mp;
 1997         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 1998         struct inpcb *in6p;
 1999         struct inpcb *last = NULL;
 2000         struct sockaddr_in6 fromsa;
 2001         struct icmp6_hdr *icmp6;
 2002         struct mbuf *opts = NULL;
 2003 
 2004 #ifndef PULLDOWN_TEST
 2005         /* this is assumed to be safe. */
 2006         icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
 2007 #else
 2008         IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
 2009         if (icmp6 == NULL) {
 2010                 /* m is already reclaimed */
 2011                 return (IPPROTO_DONE);
 2012         }
 2013 #endif
 2014 
 2015         /*
 2016          * XXX: the address may have embedded scope zone ID, which should be
 2017          * hidden from applications.
 2018          */
 2019         bzero(&fromsa, sizeof(fromsa));
 2020         fromsa.sin6_family = AF_INET6;
 2021         fromsa.sin6_len = sizeof(struct sockaddr_in6);
 2022         fromsa.sin6_addr = ip6->ip6_src;
 2023         if (sa6_recoverscope(&fromsa)) {
 2024                 m_freem(m);
 2025                 return (IPPROTO_DONE);
 2026         }
 2027 
 2028         INP_INFO_RLOCK(&V_ripcbinfo);
 2029         LIST_FOREACH(in6p, &V_ripcb, inp_list) {
 2030                 if ((in6p->inp_vflag & INP_IPV6) == 0)
 2031                         continue;
 2032                 if (in6p->inp_ip_p != IPPROTO_ICMPV6)
 2033                         continue;
 2034                 if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_laddr) &&
 2035                    !IN6_ARE_ADDR_EQUAL(&in6p->in6p_laddr, &ip6->ip6_dst))
 2036                         continue;
 2037                 if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr) &&
 2038                    !IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr, &ip6->ip6_src))
 2039                         continue;
 2040                 INP_RLOCK(in6p);
 2041                 if (ICMP6_FILTER_WILLBLOCK(icmp6->icmp6_type,
 2042                     in6p->in6p_icmp6filt)) {
 2043                         INP_RUNLOCK(in6p);
 2044                         continue;
 2045                 }
 2046                 if (last != NULL) {
 2047                         struct  mbuf *n = NULL;
 2048 
 2049                         /*
 2050                          * Recent network drivers tend to allocate a single
 2051                          * mbuf cluster, rather than to make a couple of
 2052                          * mbufs without clusters.  Also, since the IPv6 code
 2053                          * path tries to avoid m_pullup(), it is highly
 2054                          * probable that we still have an mbuf cluster here
 2055                          * even though the necessary length can be stored in an
 2056                          * mbuf's internal buffer.
 2057                          * Meanwhile, the default size of the receive socket
 2058                          * buffer for raw sockets is not so large.  This means
 2059                          * the possibility of packet loss is relatively higher
 2060                          * than before.  To avoid this scenario, we copy the
 2061                          * received data to a separate mbuf that does not use
 2062                          * a cluster, if possible.
 2063                          * XXX: it is better to copy the data after stripping
 2064                          * intermediate headers.
 2065                          */
 2066                         if ((m->m_flags & M_EXT) && m->m_next == NULL &&
 2067                             m->m_len <= MHLEN) {
 2068                                 MGET(n, M_DONTWAIT, m->m_type);
 2069                                 if (n != NULL) {
 2070                                         if (m_dup_pkthdr(n, m, M_NOWAIT)) {
 2071                                                 bcopy(m->m_data, n->m_data,
 2072                                                       m->m_len);
 2073                                                 n->m_len = m->m_len;
 2074                                         } else {
 2075                                                 m_free(n);
 2076                                                 n = NULL;
 2077                                         }
 2078                                 }
 2079                         }
 2080                         if (n != NULL ||
 2081                             (n = m_copy(m, 0, (int)M_COPYALL)) != NULL) {
 2082                                 if (last->inp_flags & INP_CONTROLOPTS)
 2083                                         ip6_savecontrol(last, n, &opts);
 2084                                 /* strip intermediate headers */
 2085                                 m_adj(n, off);
 2086                                 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
 2087                                 if (sbappendaddr_locked(
 2088                                     &last->inp_socket->so_rcv,
 2089                                     (struct sockaddr *)&fromsa, n, opts)
 2090                                     == 0) {
 2091                                         /* should notify about lost packet */
 2092                                         m_freem(n);
 2093                                         if (opts) {
 2094                                                 m_freem(opts);
 2095                                         }
 2096                                         SOCKBUF_UNLOCK(
 2097                                             &last->inp_socket->so_rcv);
 2098                                 } else
 2099                                         sorwakeup_locked(last->inp_socket);
 2100                                 opts = NULL;
 2101                         }
 2102                         INP_RUNLOCK(last);
 2103                 }
 2104                 last = in6p;
 2105         }
 2106         INP_INFO_RUNLOCK(&V_ripcbinfo);
 2107         if (last != NULL) {
 2108                 if (last->inp_flags & INP_CONTROLOPTS)
 2109                         ip6_savecontrol(last, m, &opts);
 2110                 /* strip intermediate headers */
 2111                 m_adj(m, off);
 2112 
 2113                 /* avoid using mbuf clusters if possible (see above) */
 2114                 if ((m->m_flags & M_EXT) && m->m_next == NULL &&
 2115                     m->m_len <= MHLEN) {
 2116                         struct mbuf *n;
 2117 
 2118                         MGET(n, M_DONTWAIT, m->m_type);
 2119                         if (n != NULL) {
 2120                                 if (m_dup_pkthdr(n, m, M_NOWAIT)) {
 2121                                         bcopy(m->m_data, n->m_data, m->m_len);
 2122                                         n->m_len = m->m_len;
 2123 
 2124                                         m_freem(m);
 2125                                         m = n;
 2126                                 } else {
 2127                                         m_freem(n);
 2128                                         n = NULL;
 2129                                 }
 2130                         }
 2131                 }
 2132                 SOCKBUF_LOCK(&last->inp_socket->so_rcv);
 2133                 if (sbappendaddr_locked(&last->inp_socket->so_rcv,
 2134                     (struct sockaddr *)&fromsa, m, opts) == 0) {
 2135                         m_freem(m);
 2136                         if (opts)
 2137                                 m_freem(opts);
 2138                         SOCKBUF_UNLOCK(&last->inp_socket->so_rcv);
 2139                 } else
 2140                         sorwakeup_locked(last->inp_socket);
 2141                 INP_RUNLOCK(last);
 2142         } else {
 2143                 m_freem(m);
 2144                 IP6STAT_DEC(ip6s_delivered);
 2145         }
 2146         return IPPROTO_DONE;
 2147 }
 2148 
 2149 /*
 2150  * Reflect the ip6 packet back to the source.
 2151  * OFF points to the icmp6 header, counted from the top of the mbuf.
 2152  */
 2153 void
 2154 icmp6_reflect(struct mbuf *m, size_t off)
 2155 {
 2156         struct ip6_hdr *ip6;
 2157         struct icmp6_hdr *icmp6;
 2158         struct in6_ifaddr *ia = NULL;
 2159         int plen;
 2160         int type, code;
 2161         struct ifnet *outif = NULL;
 2162         struct in6_addr origdst, src, *srcp = NULL;
 2163 
 2164         /* too short to reflect */
 2165         if (off < sizeof(struct ip6_hdr)) {
 2166                 nd6log((LOG_DEBUG,
 2167                     "sanity fail: off=%lx, sizeof(ip6)=%lx in %s:%d\n",
 2168                     (u_long)off, (u_long)sizeof(struct ip6_hdr),
 2169                     __FILE__, __LINE__));
 2170                 goto bad;
 2171         }
 2172 
 2173         /*
 2174          * If there are extra headers between IPv6 and ICMPv6, strip
 2175          * off that header first.
 2176          */
 2177 #ifdef DIAGNOSTIC
 2178         if (sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) > MHLEN)
 2179                 panic("assumption failed in icmp6_reflect");
 2180 #endif
 2181         if (off > sizeof(struct ip6_hdr)) {
 2182                 size_t l;
 2183                 struct ip6_hdr nip6;
 2184 
 2185                 l = off - sizeof(struct ip6_hdr);
 2186                 m_copydata(m, 0, sizeof(nip6), (caddr_t)&nip6);
 2187                 m_adj(m, l);
 2188                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
 2189                 if (m->m_len < l) {
 2190                         if ((m = m_pullup(m, l)) == NULL)
 2191                                 return;
 2192                 }
 2193                 bcopy((caddr_t)&nip6, mtod(m, caddr_t), sizeof(nip6));
 2194         } else /* off == sizeof(struct ip6_hdr) */ {
 2195                 size_t l;
 2196                 l = sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr);
 2197                 if (m->m_len < l) {
 2198                         if ((m = m_pullup(m, l)) == NULL)
 2199                                 return;
 2200                 }
 2201         }
 2202         plen = m->m_pkthdr.len - sizeof(struct ip6_hdr);
 2203         ip6 = mtod(m, struct ip6_hdr *);
 2204         ip6->ip6_nxt = IPPROTO_ICMPV6;
 2205         icmp6 = (struct icmp6_hdr *)(ip6 + 1);
 2206         type = icmp6->icmp6_type; /* keep type for statistics */
 2207         code = icmp6->icmp6_code; /* ditto. */
 2208 
 2209         origdst = ip6->ip6_dst;
 2210         /*
 2211          * ip6_input() drops a packet if its src is multicast.
 2212          * So, the src is never multicast.
 2213          */
 2214         ip6->ip6_dst = ip6->ip6_src;
 2215 
 2216         /*
 2217          * If the incoming packet was addressed directly to us (i.e. unicast),
 2218          * use dst as the src for the reply.
 2219          * The IN6_IFF_NOTREADY case should be VERY rare, but is possible
 2220          * (for example) when we encounter an error while forwarding procedure
 2221          * destined to a duplicated address of ours.
 2222          * Note that ip6_getdstifaddr() may fail if we are in an error handling
 2223          * procedure of an outgoing packet of our own, in which case we need
 2224          * to search in the ifaddr list.
 2225          */
 2226         if (!IN6_IS_ADDR_MULTICAST(&origdst)) {
 2227                 if ((ia = ip6_getdstifaddr(m))) {
 2228                         if (!(ia->ia6_flags &
 2229                             (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY)))
 2230                                 srcp = &ia->ia_addr.sin6_addr;
 2231                 } else {
 2232                         struct sockaddr_in6 d;
 2233 
 2234                         bzero(&d, sizeof(d));
 2235                         d.sin6_family = AF_INET6;
 2236                         d.sin6_len = sizeof(d);
 2237                         d.sin6_addr = origdst;
 2238                         ia = (struct in6_ifaddr *)
 2239                             ifa_ifwithaddr((struct sockaddr *)&d);
 2240                         if (ia &&
 2241                             !(ia->ia6_flags &
 2242                             (IN6_IFF_ANYCAST|IN6_IFF_NOTREADY))) {
 2243                                 srcp = &ia->ia_addr.sin6_addr;
 2244                         }
 2245                 }
 2246         }
 2247 
 2248         if (srcp == NULL) {
 2249                 int e;
 2250                 struct sockaddr_in6 sin6;
 2251                 struct route_in6 ro;
 2252 
 2253                 /*
 2254                  * This case matches to multicasts, our anycast, or unicasts
 2255                  * that we do not own.  Select a source address based on the
 2256                  * source address of the erroneous packet.
 2257                  */
 2258                 bzero(&sin6, sizeof(sin6));
 2259                 sin6.sin6_family = AF_INET6;
 2260                 sin6.sin6_len = sizeof(sin6);
 2261                 sin6.sin6_addr = ip6->ip6_dst; /* zone ID should be embedded */
 2262 
 2263                 bzero(&ro, sizeof(ro));
 2264                 e = in6_selectsrc(&sin6, NULL, NULL, &ro, NULL, &outif, &src);
 2265                 if (ro.ro_rt)
 2266                         RTFREE(ro.ro_rt); /* XXX: we could use this */
 2267                 if (e) {
 2268                         char ip6buf[INET6_ADDRSTRLEN];
 2269                         nd6log((LOG_DEBUG,
 2270                             "icmp6_reflect: source can't be determined: "
 2271                             "dst=%s, error=%d\n",
 2272                             ip6_sprintf(ip6buf, &sin6.sin6_addr), e));
 2273                         goto bad;
 2274                 }
 2275                 srcp = &src;
 2276         }
 2277 
 2278         ip6->ip6_src = *srcp;
 2279         ip6->ip6_flow = 0;
 2280         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
 2281         ip6->ip6_vfc |= IPV6_VERSION;
 2282         ip6->ip6_nxt = IPPROTO_ICMPV6;
 2283         if (outif)
 2284                 ip6->ip6_hlim = ND_IFINFO(outif)->chlim;
 2285         else if (m->m_pkthdr.rcvif) {
 2286                 /* XXX: This may not be the outgoing interface */
 2287                 ip6->ip6_hlim = ND_IFINFO(m->m_pkthdr.rcvif)->chlim;
 2288         } else
 2289                 ip6->ip6_hlim = V_ip6_defhlim;
 2290 
 2291         icmp6->icmp6_cksum = 0;
 2292         icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
 2293             sizeof(struct ip6_hdr), plen);
 2294 
 2295         /*
 2296          * XXX option handling
 2297          */
 2298 
 2299         m->m_flags &= ~(M_BCAST|M_MCAST);
 2300 
 2301         m_addr_changed(m);
 2302 
 2303         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
 2304         if (outif)
 2305                 icmp6_ifoutstat_inc(outif, type, code);
 2306 
 2307         if (ia != NULL)
 2308                 ifa_free(&ia->ia_ifa);
 2309         return;
 2310 
 2311  bad:
 2312         if (ia != NULL)
 2313                 ifa_free(&ia->ia_ifa);
 2314         m_freem(m);
 2315         return;
 2316 }
 2317 
 2318 void
 2319 icmp6_fasttimo(void)
 2320 {
 2321 
 2322         mld_fasttimo();
 2323 }
 2324 
 2325 void
 2326 icmp6_slowtimo(void)
 2327 {
 2328 
 2329         mld_slowtimo();
 2330 }
 2331 
 2332 static const char *
 2333 icmp6_redirect_diag(struct in6_addr *src6, struct in6_addr *dst6,
 2334     struct in6_addr *tgt6)
 2335 {
 2336         static char buf[1024];
 2337         char ip6bufs[INET6_ADDRSTRLEN];
 2338         char ip6bufd[INET6_ADDRSTRLEN];
 2339         char ip6buft[INET6_ADDRSTRLEN];
 2340         snprintf(buf, sizeof(buf), "(src=%s dst=%s tgt=%s)",
 2341             ip6_sprintf(ip6bufs, src6), ip6_sprintf(ip6bufd, dst6),
 2342             ip6_sprintf(ip6buft, tgt6));
 2343         return buf;
 2344 }
 2345 
 2346 void
 2347 icmp6_redirect_input(struct mbuf *m, int off)
 2348 {
 2349         struct ifnet *ifp;
 2350         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 2351         struct nd_redirect *nd_rd;
 2352         int icmp6len = ntohs(ip6->ip6_plen);
 2353         char *lladdr = NULL;
 2354         int lladdrlen = 0;
 2355         struct rtentry *rt = NULL;
 2356         int is_router;
 2357         int is_onlink;
 2358         struct in6_addr src6 = ip6->ip6_src;
 2359         struct in6_addr redtgt6;
 2360         struct in6_addr reddst6;
 2361         union nd_opts ndopts;
 2362         char ip6buf[INET6_ADDRSTRLEN];
 2363 
 2364         M_ASSERTPKTHDR(m);
 2365         KASSERT(m->m_pkthdr.rcvif != NULL, ("%s: no rcvif", __func__));
 2366 
 2367         ifp = m->m_pkthdr.rcvif;
 2368 
 2369         /* XXX if we are router, we don't update route by icmp6 redirect */
 2370         if (V_ip6_forwarding)
 2371                 goto freeit;
 2372         if (!V_icmp6_rediraccept)
 2373                 goto freeit;
 2374 
 2375 #ifndef PULLDOWN_TEST
 2376         IP6_EXTHDR_CHECK(m, off, icmp6len,);
 2377         nd_rd = (struct nd_redirect *)((caddr_t)ip6 + off);
 2378 #else
 2379         IP6_EXTHDR_GET(nd_rd, struct nd_redirect *, m, off, icmp6len);
 2380         if (nd_rd == NULL) {
 2381                 ICMP6STAT_INC(icp6s_tooshort);
 2382                 return;
 2383         }
 2384 #endif
 2385         redtgt6 = nd_rd->nd_rd_target;
 2386         reddst6 = nd_rd->nd_rd_dst;
 2387 
 2388         if (in6_setscope(&redtgt6, m->m_pkthdr.rcvif, NULL) ||
 2389             in6_setscope(&reddst6, m->m_pkthdr.rcvif, NULL)) {
 2390                 goto freeit;
 2391         }
 2392 
 2393         /* validation */
 2394         if (!IN6_IS_ADDR_LINKLOCAL(&src6)) {
 2395                 nd6log((LOG_ERR,
 2396                     "ICMP6 redirect sent from %s rejected; "
 2397                     "must be from linklocal\n",
 2398                     ip6_sprintf(ip6buf, &src6)));
 2399                 goto bad;
 2400         }
 2401         if (ip6->ip6_hlim != 255) {
 2402                 nd6log((LOG_ERR,
 2403                     "ICMP6 redirect sent from %s rejected; "
 2404                     "hlim=%d (must be 255)\n",
 2405                     ip6_sprintf(ip6buf, &src6), ip6->ip6_hlim));
 2406                 goto bad;
 2407         }
 2408     {
 2409         /* ip6->ip6_src must be equal to gw for icmp6->icmp6_reddst */
 2410         struct sockaddr_in6 sin6;
 2411         struct in6_addr *gw6;
 2412 
 2413         bzero(&sin6, sizeof(sin6));
 2414         sin6.sin6_family = AF_INET6;
 2415         sin6.sin6_len = sizeof(struct sockaddr_in6);
 2416         bcopy(&reddst6, &sin6.sin6_addr, sizeof(reddst6));
 2417         rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL, RT_DEFAULT_FIB);
 2418         if (rt) {
 2419                 if (rt->rt_gateway == NULL ||
 2420                     rt->rt_gateway->sa_family != AF_INET6) {
 2421                         RTFREE_LOCKED(rt);
 2422                         nd6log((LOG_ERR,
 2423                             "ICMP6 redirect rejected; no route "
 2424                             "with inet6 gateway found for redirect dst: %s\n",
 2425                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2426                         goto bad;
 2427                 }
 2428 
 2429                 gw6 = &(((struct sockaddr_in6 *)rt->rt_gateway)->sin6_addr);
 2430                 if (bcmp(&src6, gw6, sizeof(struct in6_addr)) != 0) {
 2431                         RTFREE_LOCKED(rt);
 2432                         nd6log((LOG_ERR,
 2433                             "ICMP6 redirect rejected; "
 2434                             "not equal to gw-for-src=%s (must be same): "
 2435                             "%s\n",
 2436                             ip6_sprintf(ip6buf, gw6),
 2437                             icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2438                         goto bad;
 2439                 }
 2440         } else {
 2441                 nd6log((LOG_ERR,
 2442                     "ICMP6 redirect rejected; "
 2443                     "no route found for redirect dst: %s\n",
 2444                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2445                 goto bad;
 2446         }
 2447         RTFREE_LOCKED(rt);
 2448         rt = NULL;
 2449     }
 2450         if (IN6_IS_ADDR_MULTICAST(&reddst6)) {
 2451                 nd6log((LOG_ERR,
 2452                     "ICMP6 redirect rejected; "
 2453                     "redirect dst must be unicast: %s\n",
 2454                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2455                 goto bad;
 2456         }
 2457 
 2458         is_router = is_onlink = 0;
 2459         if (IN6_IS_ADDR_LINKLOCAL(&redtgt6))
 2460                 is_router = 1;  /* router case */
 2461         if (bcmp(&redtgt6, &reddst6, sizeof(redtgt6)) == 0)
 2462                 is_onlink = 1;  /* on-link destination case */
 2463         if (!is_router && !is_onlink) {
 2464                 nd6log((LOG_ERR,
 2465                     "ICMP6 redirect rejected; "
 2466                     "neither router case nor onlink case: %s\n",
 2467                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2468                 goto bad;
 2469         }
 2470         /* validation passed */
 2471 
 2472         icmp6len -= sizeof(*nd_rd);
 2473         nd6_option_init(nd_rd + 1, icmp6len, &ndopts);
 2474         if (nd6_options(&ndopts) < 0) {
 2475                 nd6log((LOG_INFO, "%s: invalid ND option, rejected: %s\n",
 2476                     __func__, icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2477                 /* nd6_options have incremented stats */
 2478                 goto freeit;
 2479         }
 2480 
 2481         if (ndopts.nd_opts_tgt_lladdr) {
 2482                 lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
 2483                 lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
 2484         }
 2485 
 2486         if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
 2487                 nd6log((LOG_INFO, "%s: lladdrlen mismatch for %s "
 2488                     "(if %d, icmp6 packet %d): %s\n",
 2489                     __func__, ip6_sprintf(ip6buf, &redtgt6),
 2490                     ifp->if_addrlen, lladdrlen - 2,
 2491                     icmp6_redirect_diag(&src6, &reddst6, &redtgt6)));
 2492                 goto bad;
 2493         }
 2494 
 2495         /* RFC 2461 8.3 */
 2496         nd6_cache_lladdr(ifp, &redtgt6, lladdr, lladdrlen, ND_REDIRECT,
 2497             is_onlink ? ND_REDIRECT_ONLINK : ND_REDIRECT_ROUTER);
 2498 
 2499         if (!is_onlink) {       /* better router case.  perform rtredirect. */
 2500                 /* perform rtredirect */
 2501                 struct sockaddr_in6 sdst;
 2502                 struct sockaddr_in6 sgw;
 2503                 struct sockaddr_in6 ssrc;
 2504                 u_int fibnum;
 2505 
 2506                 bzero(&sdst, sizeof(sdst));
 2507                 bzero(&sgw, sizeof(sgw));
 2508                 bzero(&ssrc, sizeof(ssrc));
 2509                 sdst.sin6_family = sgw.sin6_family = ssrc.sin6_family = AF_INET6;
 2510                 sdst.sin6_len = sgw.sin6_len = ssrc.sin6_len =
 2511                         sizeof(struct sockaddr_in6);
 2512                 bcopy(&redtgt6, &sgw.sin6_addr, sizeof(struct in6_addr));
 2513                 bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
 2514                 bcopy(&src6, &ssrc.sin6_addr, sizeof(struct in6_addr));
 2515                 for (fibnum = 0; fibnum < rt_numfibs; fibnum++)
 2516                         in6_rtredirect((struct sockaddr *)&sdst,
 2517                             (struct sockaddr *)&sgw, (struct sockaddr *)NULL,
 2518                             RTF_GATEWAY | RTF_HOST, (struct sockaddr *)&ssrc,
 2519                             fibnum);
 2520         }
 2521         /* finally update cached route in each socket via pfctlinput */
 2522     {
 2523         struct sockaddr_in6 sdst;
 2524 
 2525         bzero(&sdst, sizeof(sdst));
 2526         sdst.sin6_family = AF_INET6;
 2527         sdst.sin6_len = sizeof(struct sockaddr_in6);
 2528         bcopy(&reddst6, &sdst.sin6_addr, sizeof(struct in6_addr));
 2529         pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&sdst);
 2530 #ifdef IPSEC
 2531         key_sa_routechange((struct sockaddr *)&sdst);
 2532 #endif /* IPSEC */
 2533     }
 2534 
 2535  freeit:
 2536         m_freem(m);
 2537         return;
 2538 
 2539  bad:
 2540         ICMP6STAT_INC(icp6s_badredirect);
 2541         m_freem(m);
 2542 }
 2543 
 2544 void
 2545 icmp6_redirect_output(struct mbuf *m0, struct rtentry *rt)
 2546 {
 2547         struct ifnet *ifp;      /* my outgoing interface */
 2548         struct in6_addr *ifp_ll6;
 2549         struct in6_addr *router_ll6;
 2550         struct ip6_hdr *sip6;   /* m0 as struct ip6_hdr */
 2551         struct mbuf *m = NULL;  /* newly allocated one */
 2552         struct m_tag *mtag;
 2553         struct ip6_hdr *ip6;    /* m as struct ip6_hdr */
 2554         struct nd_redirect *nd_rd;
 2555         struct llentry *ln = NULL;
 2556         size_t maxlen;
 2557         u_char *p;
 2558         struct ifnet *outif = NULL;
 2559         struct sockaddr_in6 src_sa;
 2560 
 2561         icmp6_errcount(&V_icmp6stat.icp6s_outerrhist, ND_REDIRECT, 0);
 2562 
 2563         /* if we are not router, we don't send icmp6 redirect */
 2564         if (!V_ip6_forwarding)
 2565                 goto fail;
 2566 
 2567         /* sanity check */
 2568         if (!m0 || !rt || !(rt->rt_flags & RTF_UP) || !(ifp = rt->rt_ifp))
 2569                 goto fail;
 2570 
 2571         /*
 2572          * Address check:
 2573          *  the source address must identify a neighbor, and
 2574          *  the destination address must not be a multicast address
 2575          *  [RFC 2461, sec 8.2]
 2576          */
 2577         sip6 = mtod(m0, struct ip6_hdr *);
 2578         bzero(&src_sa, sizeof(src_sa));
 2579         src_sa.sin6_family = AF_INET6;
 2580         src_sa.sin6_len = sizeof(src_sa);
 2581         src_sa.sin6_addr = sip6->ip6_src;
 2582         if (nd6_is_addr_neighbor(&src_sa, ifp) == 0)
 2583                 goto fail;
 2584         if (IN6_IS_ADDR_MULTICAST(&sip6->ip6_dst))
 2585                 goto fail;      /* what should we do here? */
 2586 
 2587         /* rate limit */
 2588         if (icmp6_ratelimit(&sip6->ip6_src, ND_REDIRECT, 0))
 2589                 goto fail;
 2590 
 2591         /*
 2592          * Since we are going to append up to 1280 bytes (= IPV6_MMTU),
 2593          * we almost always ask for an mbuf cluster for simplicity.
 2594          * (MHLEN < IPV6_MMTU is almost always true)
 2595          */
 2596 #if IPV6_MMTU >= MCLBYTES
 2597 # error assumption failed about IPV6_MMTU and MCLBYTES
 2598 #endif
 2599         MGETHDR(m, M_DONTWAIT, MT_HEADER);
 2600         if (m && IPV6_MMTU >= MHLEN)
 2601                 MCLGET(m, M_DONTWAIT);
 2602         if (!m)
 2603                 goto fail;
 2604         M_SETFIB(m, rt->rt_fibnum);
 2605         m->m_pkthdr.rcvif = NULL;
 2606         m->m_len = 0;
 2607         maxlen = M_TRAILINGSPACE(m);
 2608         maxlen = min(IPV6_MMTU, maxlen);
 2609         /* just for safety */
 2610         if (maxlen < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) +
 2611             ((sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7)) {
 2612                 goto fail;
 2613         }
 2614 
 2615         {
 2616                 /* get ip6 linklocal address for ifp(my outgoing interface). */
 2617                 struct in6_ifaddr *ia;
 2618                 if ((ia = in6ifa_ifpforlinklocal(ifp,
 2619                                                  IN6_IFF_NOTREADY|
 2620                                                  IN6_IFF_ANYCAST)) == NULL)
 2621                         goto fail;
 2622                 ifp_ll6 = &ia->ia_addr.sin6_addr;
 2623                 /* XXXRW: reference released prematurely. */
 2624                 ifa_free(&ia->ia_ifa);
 2625         }
 2626 
 2627         /* get ip6 linklocal address for the router. */
 2628         if (rt->rt_gateway && (rt->rt_flags & RTF_GATEWAY)) {
 2629                 struct sockaddr_in6 *sin6;
 2630                 sin6 = (struct sockaddr_in6 *)rt->rt_gateway;
 2631                 router_ll6 = &sin6->sin6_addr;
 2632                 if (!IN6_IS_ADDR_LINKLOCAL(router_ll6))
 2633                         router_ll6 = (struct in6_addr *)NULL;
 2634         } else
 2635                 router_ll6 = (struct in6_addr *)NULL;
 2636 
 2637         /* ip6 */
 2638         ip6 = mtod(m, struct ip6_hdr *);
 2639         ip6->ip6_flow = 0;
 2640         ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
 2641         ip6->ip6_vfc |= IPV6_VERSION;
 2642         /* ip6->ip6_plen will be set later */
 2643         ip6->ip6_nxt = IPPROTO_ICMPV6;
 2644         ip6->ip6_hlim = 255;
 2645         /* ip6->ip6_src must be linklocal addr for my outgoing if. */
 2646         bcopy(ifp_ll6, &ip6->ip6_src, sizeof(struct in6_addr));
 2647         bcopy(&sip6->ip6_src, &ip6->ip6_dst, sizeof(struct in6_addr));
 2648 
 2649         /* ND Redirect */
 2650         nd_rd = (struct nd_redirect *)(ip6 + 1);
 2651         nd_rd->nd_rd_type = ND_REDIRECT;
 2652         nd_rd->nd_rd_code = 0;
 2653         nd_rd->nd_rd_reserved = 0;
 2654         if (rt->rt_flags & RTF_GATEWAY) {
 2655                 /*
 2656                  * nd_rd->nd_rd_target must be a link-local address in
 2657                  * better router cases.
 2658                  */
 2659                 if (!router_ll6)
 2660                         goto fail;
 2661                 bcopy(router_ll6, &nd_rd->nd_rd_target,
 2662                     sizeof(nd_rd->nd_rd_target));
 2663                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
 2664                     sizeof(nd_rd->nd_rd_dst));
 2665         } else {
 2666                 /* make sure redtgt == reddst */
 2667                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_target,
 2668                     sizeof(nd_rd->nd_rd_target));
 2669                 bcopy(&sip6->ip6_dst, &nd_rd->nd_rd_dst,
 2670                     sizeof(nd_rd->nd_rd_dst));
 2671         }
 2672 
 2673         p = (u_char *)(nd_rd + 1);
 2674 
 2675         if (!router_ll6)
 2676                 goto nolladdropt;
 2677 
 2678         {
 2679                 /* target lladdr option */
 2680                 int len;
 2681                 struct nd_opt_hdr *nd_opt;
 2682                 char *lladdr;
 2683 
 2684                 IF_AFDATA_LOCK(ifp);
 2685                 ln = nd6_lookup(router_ll6, 0, ifp);
 2686                 IF_AFDATA_UNLOCK(ifp);
 2687                 if (ln == NULL)
 2688                         goto nolladdropt;
 2689 
 2690                 len = sizeof(*nd_opt) + ifp->if_addrlen;
 2691                 len = (len + 7) & ~7;   /* round by 8 */
 2692                 /* safety check */
 2693                 if (len + (p - (u_char *)ip6) > maxlen)                         
 2694                         goto nolladdropt;
 2695 
 2696                 if (ln->la_flags & LLE_VALID) {
 2697                         nd_opt = (struct nd_opt_hdr *)p;
 2698                         nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
 2699                         nd_opt->nd_opt_len = len >> 3;
 2700                         lladdr = (char *)(nd_opt + 1);
 2701                         bcopy(&ln->ll_addr, lladdr, ifp->if_addrlen);
 2702                         p += len;
 2703                 }
 2704         }
 2705 nolladdropt:
 2706         if (ln != NULL)
 2707                 LLE_RUNLOCK(ln);
 2708                 
 2709         m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
 2710 
 2711         /* just to be safe */
 2712 #ifdef M_DECRYPTED      /*not openbsd*/
 2713         if (m0->m_flags & M_DECRYPTED)
 2714                 goto noredhdropt;
 2715 #endif
 2716         if (p - (u_char *)ip6 > maxlen)
 2717                 goto noredhdropt;
 2718 
 2719         {
 2720                 /* redirected header option */
 2721                 int len;
 2722                 struct nd_opt_rd_hdr *nd_opt_rh;
 2723 
 2724                 /*
 2725                  * compute the maximum size for icmp6 redirect header option.
 2726                  * XXX room for auth header?
 2727                  */
 2728                 len = maxlen - (p - (u_char *)ip6);
 2729                 len &= ~7;
 2730 
 2731                 /* This is just for simplicity. */
 2732                 if (m0->m_pkthdr.len != m0->m_len) {
 2733                         if (m0->m_next) {
 2734                                 m_freem(m0->m_next);
 2735                                 m0->m_next = NULL;
 2736                         }
 2737                         m0->m_pkthdr.len = m0->m_len;
 2738                 }
 2739 
 2740                 /*
 2741                  * Redirected header option spec (RFC2461 4.6.3) talks nothing
 2742                  * about padding/truncate rule for the original IP packet.
 2743                  * From the discussion on IPv6imp in Feb 1999,
 2744                  * the consensus was:
 2745                  * - "attach as much as possible" is the goal
 2746                  * - pad if not aligned (original size can be guessed by
 2747                  *   original ip6 header)
 2748                  * Following code adds the padding if it is simple enough,
 2749                  * and truncates if not.
 2750                  */
 2751                 if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
 2752                         panic("assumption failed in %s:%d", __FILE__,
 2753                             __LINE__);
 2754 
 2755                 if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
 2756                         /* not enough room, truncate */
 2757                         m0->m_pkthdr.len = m0->m_len = len -
 2758                             sizeof(*nd_opt_rh);
 2759                 } else {
 2760                         /* enough room, pad or truncate */
 2761                         size_t extra;
 2762 
 2763                         extra = m0->m_pkthdr.len % 8;
 2764                         if (extra) {
 2765                                 /* pad if easy enough, truncate if not */
 2766                                 if (8 - extra <= M_TRAILINGSPACE(m0)) {
 2767                                         /* pad */
 2768                                         m0->m_len += (8 - extra);
 2769                                         m0->m_pkthdr.len += (8 - extra);
 2770                                 } else {
 2771                                         /* truncate */
 2772                                         m0->m_pkthdr.len -= extra;
 2773                                         m0->m_len -= extra;
 2774                                 }
 2775                         }
 2776                         len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
 2777                         m0->m_pkthdr.len = m0->m_len = len -
 2778                             sizeof(*nd_opt_rh);
 2779                 }
 2780 
 2781                 nd_opt_rh = (struct nd_opt_rd_hdr *)p;
 2782                 bzero(nd_opt_rh, sizeof(*nd_opt_rh));
 2783                 nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
 2784                 nd_opt_rh->nd_opt_rh_len = len >> 3;
 2785                 p += sizeof(*nd_opt_rh);
 2786                 m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
 2787 
 2788                 /* connect m0 to m */
 2789                 m_tag_delete_chain(m0, NULL);
 2790                 m0->m_flags &= ~M_PKTHDR;
 2791                 m->m_next = m0;
 2792                 m->m_pkthdr.len = m->m_len + m0->m_len;
 2793                 m0 = NULL;
 2794         }
 2795 noredhdropt:;
 2796         if (m0) {
 2797                 m_freem(m0);
 2798                 m0 = NULL;
 2799         }
 2800 
 2801         /* XXX: clear embedded link IDs in the inner header */
 2802         in6_clearscope(&sip6->ip6_src);
 2803         in6_clearscope(&sip6->ip6_dst);
 2804         in6_clearscope(&nd_rd->nd_rd_target);
 2805         in6_clearscope(&nd_rd->nd_rd_dst);
 2806 
 2807         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 2808 
 2809         nd_rd->nd_rd_cksum = 0;
 2810         nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
 2811             sizeof(*ip6), ntohs(ip6->ip6_plen));
 2812 
 2813         if (send_sendso_input_hook != NULL) {
 2814                 mtag = m_tag_get(PACKET_TAG_ND_OUTGOING, sizeof(unsigned short),
 2815                         M_NOWAIT);
 2816                 if (mtag == NULL)
 2817                         goto fail;
 2818                 *(unsigned short *)(mtag + 1) = nd_rd->nd_rd_type;
 2819                 m_tag_prepend(m, mtag);
 2820         }
 2821 
 2822         /* send the packet to outside... */
 2823         ip6_output(m, NULL, NULL, 0, NULL, &outif, NULL);
 2824         if (outif) {
 2825                 icmp6_ifstat_inc(outif, ifs6_out_msg);
 2826                 icmp6_ifstat_inc(outif, ifs6_out_redirect);
 2827         }
 2828         ICMP6STAT_INC(icp6s_outhist[ND_REDIRECT]);
 2829 
 2830         return;
 2831 
 2832 fail:
 2833         if (m)
 2834                 m_freem(m);
 2835         if (m0)
 2836                 m_freem(m0);
 2837 }
 2838 
 2839 /*
 2840  * ICMPv6 socket option processing.
 2841  */
 2842 int
 2843 icmp6_ctloutput(struct socket *so, struct sockopt *sopt)
 2844 {
 2845         int error = 0;
 2846         int optlen;
 2847         struct inpcb *inp = sotoinpcb(so);
 2848         int level, op, optname;
 2849 
 2850         if (sopt) {
 2851                 level = sopt->sopt_level;
 2852                 op = sopt->sopt_dir;
 2853                 optname = sopt->sopt_name;
 2854                 optlen = sopt->sopt_valsize;
 2855         } else
 2856                 level = op = optname = optlen = 0;
 2857 
 2858         if (level != IPPROTO_ICMPV6) {
 2859                 return EINVAL;
 2860         }
 2861 
 2862         switch (op) {
 2863         case PRCO_SETOPT:
 2864                 switch (optname) {
 2865                 case ICMP6_FILTER:
 2866                     {
 2867                         struct icmp6_filter ic6f;
 2868 
 2869                         if (optlen != sizeof(ic6f)) {
 2870                                 error = EMSGSIZE;
 2871                                 break;
 2872                         }
 2873                         error = sooptcopyin(sopt, &ic6f, optlen, optlen);
 2874                         if (error == 0) {
 2875                                 INP_WLOCK(inp);
 2876                                 *inp->in6p_icmp6filt = ic6f;
 2877                                 INP_WUNLOCK(inp);
 2878                         }
 2879                         break;
 2880                     }
 2881 
 2882                 default:
 2883                         error = ENOPROTOOPT;
 2884                         break;
 2885                 }
 2886                 break;
 2887 
 2888         case PRCO_GETOPT:
 2889                 switch (optname) {
 2890                 case ICMP6_FILTER:
 2891                     {
 2892                         struct icmp6_filter ic6f;
 2893 
 2894                         INP_RLOCK(inp);
 2895                         ic6f = *inp->in6p_icmp6filt;
 2896                         INP_RUNLOCK(inp);
 2897                         error = sooptcopyout(sopt, &ic6f, sizeof(ic6f));
 2898                         break;
 2899                     }
 2900 
 2901                 default:
 2902                         error = ENOPROTOOPT;
 2903                         break;
 2904                 }
 2905                 break;
 2906         }
 2907 
 2908         return (error);
 2909 }
 2910 
 2911 /*
 2912  * Perform rate limit check.
 2913  * Returns 0 if it is okay to send the icmp6 packet.
 2914  * Returns 1 if the router SHOULD NOT send this icmp6 packet due to rate
 2915  * limitation.
 2916  *
 2917  * XXX per-destination/type check necessary?
 2918  *
 2919  * dst - not used at this moment
 2920  * type - not used at this moment
 2921  * code - not used at this moment
 2922  */
 2923 static int
 2924 icmp6_ratelimit(const struct in6_addr *dst, const int type,
 2925     const int code)
 2926 {
 2927         int ret;
 2928 
 2929         ret = 0;        /* okay to send */
 2930 
 2931         /* PPS limit */
 2932         if (!ppsratecheck(&V_icmp6errppslim_last, &V_icmp6errpps_count,
 2933             V_icmp6errppslim)) {
 2934                 /* The packet is subject to rate limit */
 2935                 ret++;
 2936         }
 2937 
 2938         return ret;
 2939 }

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