The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet6/ip6_forward.c

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    1 /*      $FreeBSD: releng/6.3/sys/netinet6/ip6_forward.c 162254 2006-09-12 17:54:58Z jhay $      */
    2 /*      $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $    */
    3 
    4 /*-
    5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the project nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 #include "opt_ip6fw.h"
   34 #include "opt_inet.h"
   35 #include "opt_inet6.h"
   36 #include "opt_ipsec.h"
   37 #include "opt_ipstealth.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/domain.h>
   44 #include <sys/protosw.h>
   45 #include <sys/socket.h>
   46 #include <sys/errno.h>
   47 #include <sys/time.h>
   48 #include <sys/kernel.h>
   49 #include <sys/syslog.h>
   50 
   51 #include <net/if.h>
   52 #include <net/route.h>
   53 #include <net/pfil.h>
   54 
   55 #include <netinet/in.h>
   56 #include <netinet/in_var.h>
   57 #include <netinet/in_systm.h>
   58 #include <netinet/ip.h>
   59 #include <netinet/ip_var.h>
   60 #include <netinet6/in6_var.h>
   61 #include <netinet/ip6.h>
   62 #include <netinet6/ip6_var.h>
   63 #include <netinet6/scope6_var.h>
   64 #include <netinet/icmp6.h>
   65 #include <netinet6/nd6.h>
   66 
   67 #include <netinet/in_pcb.h>
   68 
   69 #ifdef IPSEC
   70 #include <netinet6/ipsec.h>
   71 #ifdef INET6
   72 #include <netinet6/ipsec6.h>
   73 #endif
   74 #include <netkey/key.h>
   75 #endif /* IPSEC */
   76 
   77 #ifdef FAST_IPSEC
   78 #include <netipsec/ipsec.h>
   79 #include <netipsec/ipsec6.h>
   80 #include <netipsec/key.h>
   81 #define IPSEC
   82 #endif /* FAST_IPSEC */
   83 
   84 #include <netinet6/ip6_fw.h>
   85 
   86 #include <net/net_osdep.h>
   87 
   88 #include <netinet6/ip6protosw.h>
   89 
   90 struct  route_in6 ip6_forward_rt;
   91 
   92 /*
   93  * Forward a packet.  If some error occurs return the sender
   94  * an icmp packet.  Note we can't always generate a meaningful
   95  * icmp message because icmp doesn't have a large enough repertoire
   96  * of codes and types.
   97  *
   98  * If not forwarding, just drop the packet.  This could be confusing
   99  * if ipforwarding was zero but some routing protocol was advancing
  100  * us as a gateway to somewhere.  However, we must let the routing
  101  * protocol deal with that.
  102  *
  103  */
  104 
  105 void
  106 ip6_forward(m, srcrt)
  107         struct mbuf *m;
  108         int srcrt;
  109 {
  110         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
  111         struct sockaddr_in6 *dst = NULL;
  112         struct rtentry *rt = NULL;
  113         int error, type = 0, code = 0;
  114         struct mbuf *mcopy = NULL;
  115         struct ifnet *origifp;  /* maybe unnecessary */
  116         u_int32_t inzone, outzone;
  117         struct in6_addr src_in6, dst_in6;
  118 #ifdef IPSEC
  119         struct secpolicy *sp = NULL;
  120         int ipsecrt = 0;
  121 #endif
  122 
  123 #ifdef IPSEC
  124         /*
  125          * Check AH/ESP integrity.
  126          */
  127         /*
  128          * Don't increment ip6s_cantforward because this is the check
  129          * before forwarding packet actually.
  130          */
  131         if (ipsec6_in_reject(m, NULL)) {
  132 #if !defined(FAST_IPSEC)
  133                 ipsec6stat.in_polvio++;
  134 #endif
  135                 m_freem(m);
  136                 return;
  137         }
  138 #endif /* IPSEC */
  139 
  140         /*
  141          * Do not forward packets to multicast destination (should be handled
  142          * by ip6_mforward().
  143          * Do not forward packets with unspecified source.  It was discussed
  144          * in July 2000, on the ipngwg mailing list.
  145          */
  146         if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
  147             IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
  148             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
  149                 ip6stat.ip6s_cantforward++;
  150                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
  151                 if (ip6_log_time + ip6_log_interval < time_second) {
  152                         ip6_log_time = time_second;
  153                         log(LOG_DEBUG,
  154                             "cannot forward "
  155                             "from %s to %s nxt %d received on %s\n",
  156                             ip6_sprintf(&ip6->ip6_src),
  157                             ip6_sprintf(&ip6->ip6_dst),
  158                             ip6->ip6_nxt,
  159                             if_name(m->m_pkthdr.rcvif));
  160                 }
  161                 m_freem(m);
  162                 return;
  163         }
  164 
  165 #ifdef IPSTEALTH
  166         if (!ip6stealth) {
  167 #endif
  168         if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
  169                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
  170                 icmp6_error(m, ICMP6_TIME_EXCEEDED,
  171                                 ICMP6_TIME_EXCEED_TRANSIT, 0);
  172                 return;
  173         }
  174         ip6->ip6_hlim -= IPV6_HLIMDEC;
  175 
  176 #ifdef IPSTEALTH
  177         }
  178 #endif
  179 
  180         /*
  181          * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
  182          * size of IPv6 + ICMPv6 headers) bytes of the packet in case
  183          * we need to generate an ICMP6 message to the src.
  184          * Thanks to M_EXT, in most cases copy will not occur.
  185          *
  186          * It is important to save it before IPsec processing as IPsec
  187          * processing may modify the mbuf.
  188          */
  189         mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
  190 
  191 #ifdef IPSEC
  192         /* get a security policy for this packet */
  193         sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
  194             IP_FORWARDING, &error);
  195         if (sp == NULL) {
  196                 ipsec6stat.out_inval++;
  197                 ip6stat.ip6s_cantforward++;
  198                 if (mcopy) {
  199 #if 0
  200                         /* XXX: what icmp ? */
  201 #else
  202                         m_freem(mcopy);
  203 #endif
  204                 }
  205                 m_freem(m);
  206                 return;
  207         }
  208 
  209         error = 0;
  210 
  211         /* check policy */
  212         switch (sp->policy) {
  213         case IPSEC_POLICY_DISCARD:
  214                 /*
  215                  * This packet is just discarded.
  216                  */
  217                 ipsec6stat.out_polvio++;
  218                 ip6stat.ip6s_cantforward++;
  219                 key_freesp(sp);
  220                 if (mcopy) {
  221 #if 0
  222                         /* XXX: what icmp ? */
  223 #else
  224                         m_freem(mcopy);
  225 #endif
  226                 }
  227                 m_freem(m);
  228                 return;
  229 
  230         case IPSEC_POLICY_BYPASS:
  231         case IPSEC_POLICY_NONE:
  232                 /* no need to do IPsec. */
  233                 key_freesp(sp);
  234                 goto skip_ipsec;
  235 
  236         case IPSEC_POLICY_IPSEC:
  237                 if (sp->req == NULL) {
  238                         /* XXX should be panic ? */
  239                         printf("ip6_forward: No IPsec request specified.\n");
  240                         ip6stat.ip6s_cantforward++;
  241                         key_freesp(sp);
  242                         if (mcopy) {
  243 #if 0
  244                                 /* XXX: what icmp ? */
  245 #else
  246                                 m_freem(mcopy);
  247 #endif
  248                         }
  249                         m_freem(m);
  250                         return;
  251                 }
  252                 /* do IPsec */
  253                 break;
  254 
  255         case IPSEC_POLICY_ENTRUST:
  256         default:
  257                 /* should be panic ?? */
  258                 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
  259                 key_freesp(sp);
  260                 goto skip_ipsec;
  261         }
  262 
  263     {
  264         struct ipsecrequest *isr = NULL;
  265         struct ipsec_output_state state;
  266 
  267         /*
  268          * when the kernel forwards a packet, it is not proper to apply
  269          * IPsec transport mode to the packet is not proper.  this check
  270          * avoid from this.
  271          * at present, if there is even a transport mode SA request in the
  272          * security policy, the kernel does not apply IPsec to the packet.
  273          * this check is not enough because the following case is valid.
  274          *      ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
  275          */
  276         for (isr = sp->req; isr; isr = isr->next) {
  277                 if (isr->saidx.mode == IPSEC_MODE_ANY)
  278                         goto doipsectunnel;
  279                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  280                         goto doipsectunnel;
  281         }
  282 
  283         /*
  284          * if there's no need for tunnel mode IPsec, skip.
  285          */
  286         if (!isr)
  287                 goto skip_ipsec;
  288 
  289     doipsectunnel:
  290         /*
  291          * All the extension headers will become inaccessible
  292          * (since they can be encrypted).
  293          * Don't panic, we need no more updates to extension headers
  294          * on inner IPv6 packet (since they are now encapsulated).
  295          *
  296          * IPv6 [ESP|AH] IPv6 [extension headers] payload
  297          */
  298         bzero(&state, sizeof(state));
  299         state.m = m;
  300         state.ro = NULL;        /* update at ipsec6_output_tunnel() */
  301         state.dst = NULL;       /* update at ipsec6_output_tunnel() */
  302 
  303         error = ipsec6_output_tunnel(&state, sp, 0);
  304 
  305         m = state.m;
  306         key_freesp(sp);
  307 
  308         if (error) {
  309                 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
  310                 switch (error) {
  311                 case EHOSTUNREACH:
  312                 case ENETUNREACH:
  313                 case EMSGSIZE:
  314                 case ENOBUFS:
  315                 case ENOMEM:
  316                         break;
  317                 default:
  318                         printf("ip6_output (ipsec): error code %d\n", error);
  319                         /* FALLTHROUGH */
  320                 case ENOENT:
  321                         /* don't show these error codes to the user */
  322                         break;
  323                 }
  324                 ip6stat.ip6s_cantforward++;
  325                 if (mcopy) {
  326 #if 0
  327                         /* XXX: what icmp ? */
  328 #else
  329                         m_freem(mcopy);
  330 #endif
  331                 }
  332                 m_freem(m);
  333                 return;
  334         }
  335 
  336         if (ip6 != mtod(m, struct ip6_hdr *)) {
  337                 /*
  338                  * now tunnel mode headers are added.  we are originating
  339                  * packet instead of forwarding the packet.
  340                  */
  341                 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL,
  342                     NULL);
  343                 goto freecopy;
  344         }
  345 
  346         /* adjust pointer */
  347         dst = (struct sockaddr_in6 *)state.dst;
  348         rt = state.ro ? state.ro->ro_rt : NULL;
  349         if (dst != NULL && rt != NULL)
  350                 ipsecrt = 1;
  351     }
  352     skip_ipsec:
  353 #endif /* IPSEC */
  354 
  355 #ifdef IPSEC
  356         if (ipsecrt)
  357                 goto skip_routing;
  358 #endif
  359 
  360         dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
  361         if (!srcrt) {
  362                 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */
  363                 if (ip6_forward_rt.ro_rt == 0 ||
  364                     (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) {
  365                         if (ip6_forward_rt.ro_rt) {
  366                                 RTFREE(ip6_forward_rt.ro_rt);
  367                                 ip6_forward_rt.ro_rt = 0;
  368                         }
  369 
  370                         /* this probably fails but give it a try again */
  371                         rtalloc((struct route *)&ip6_forward_rt);
  372                 }
  373 
  374                 if (ip6_forward_rt.ro_rt == 0) {
  375                         ip6stat.ip6s_noroute++;
  376                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
  377                         if (mcopy) {
  378                                 icmp6_error(mcopy, ICMP6_DST_UNREACH,
  379                                             ICMP6_DST_UNREACH_NOROUTE, 0);
  380                         }
  381                         m_freem(m);
  382                         return;
  383                 }
  384         } else if ((rt = ip6_forward_rt.ro_rt) == 0 ||
  385                    !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) {
  386                 if (ip6_forward_rt.ro_rt) {
  387                         RTFREE(ip6_forward_rt.ro_rt);
  388                         ip6_forward_rt.ro_rt = 0;
  389                 }
  390                 bzero(dst, sizeof(*dst));
  391                 dst->sin6_len = sizeof(struct sockaddr_in6);
  392                 dst->sin6_family = AF_INET6;
  393                 dst->sin6_addr = ip6->ip6_dst;
  394 
  395                 rtalloc((struct route *)&ip6_forward_rt);
  396                 if (ip6_forward_rt.ro_rt == 0) {
  397                         ip6stat.ip6s_noroute++;
  398                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
  399                         if (mcopy) {
  400                                 icmp6_error(mcopy, ICMP6_DST_UNREACH,
  401                                             ICMP6_DST_UNREACH_NOROUTE, 0);
  402                         }
  403                         m_freem(m);
  404                         return;
  405                 }
  406         }
  407         rt = ip6_forward_rt.ro_rt;
  408 #ifdef IPSEC
  409     skip_routing:;
  410 #endif
  411 
  412         /*
  413          * Source scope check: if a packet can't be delivered to its
  414          * destination for the reason that the destination is beyond the scope
  415          * of the source address, discard the packet and return an icmp6
  416          * destination unreachable error with Code 2 (beyond scope of source
  417          * address).  We use a local copy of ip6_src, since in6_setscope()
  418          * will possibly modify its first argument.
  419          * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
  420          */
  421         src_in6 = ip6->ip6_src;
  422         if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
  423                 /* XXX: this should not happen */
  424                 ip6stat.ip6s_cantforward++;
  425                 ip6stat.ip6s_badscope++;
  426                 m_freem(m);
  427                 return;
  428         }
  429         if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
  430                 ip6stat.ip6s_cantforward++;
  431                 ip6stat.ip6s_badscope++;
  432                 m_freem(m);
  433                 return;
  434         }
  435         if (inzone != outzone
  436 #ifdef IPSEC
  437             && !ipsecrt
  438 #endif
  439             ) {
  440                 ip6stat.ip6s_cantforward++;
  441                 ip6stat.ip6s_badscope++;
  442                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
  443 
  444                 if (ip6_log_time + ip6_log_interval < time_second) {
  445                         ip6_log_time = time_second;
  446                         log(LOG_DEBUG,
  447                             "cannot forward "
  448                             "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
  449                             ip6_sprintf(&ip6->ip6_src),
  450                             ip6_sprintf(&ip6->ip6_dst),
  451                             ip6->ip6_nxt,
  452                             if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
  453                 }
  454                 if (mcopy)
  455                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  456                                     ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
  457                 m_freem(m);
  458                 return;
  459         }
  460 
  461         /*
  462          * Destination scope check: if a packet is going to break the scope
  463          * zone of packet's destination address, discard it.  This case should
  464          * usually be prevented by appropriately-configured routing table, but
  465          * we need an explicit check because we may mistakenly forward the
  466          * packet to a different zone by (e.g.) a default route.
  467          */
  468         dst_in6 = ip6->ip6_dst;
  469         if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
  470             in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
  471             inzone != outzone) {
  472                 ip6stat.ip6s_cantforward++;
  473                 ip6stat.ip6s_badscope++;
  474                 m_freem(m);
  475                 return;
  476         }
  477 
  478         if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
  479                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
  480                 if (mcopy) {
  481                         u_long mtu;
  482 #ifdef IPSEC
  483                         struct secpolicy *sp;
  484                         int ipsecerror;
  485                         size_t ipsechdrsiz;
  486 #endif
  487 
  488                         mtu = IN6_LINKMTU(rt->rt_ifp);
  489 #ifdef IPSEC
  490                         /*
  491                          * When we do IPsec tunnel ingress, we need to play
  492                          * with the link value (decrement IPsec header size
  493                          * from mtu value).  The code is much simpler than v4
  494                          * case, as we have the outgoing interface for
  495                          * encapsulated packet as "rt->rt_ifp".
  496                          */
  497                         sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
  498                                 IP_FORWARDING, &ipsecerror);
  499                         if (sp) {
  500                                 ipsechdrsiz = ipsec6_hdrsiz(mcopy,
  501                                         IPSEC_DIR_OUTBOUND, NULL);
  502                                 if (ipsechdrsiz < mtu)
  503                                         mtu -= ipsechdrsiz;
  504                         }
  505 
  506                         /*
  507                          * if mtu becomes less than minimum MTU,
  508                          * tell minimum MTU (and I'll need to fragment it).
  509                          */
  510                         if (mtu < IPV6_MMTU)
  511                                 mtu = IPV6_MMTU;
  512 #endif
  513                         icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
  514                 }
  515                 m_freem(m);
  516                 return;
  517         }
  518 
  519         if (rt->rt_flags & RTF_GATEWAY)
  520                 dst = (struct sockaddr_in6 *)rt->rt_gateway;
  521 
  522         /*
  523          * If we are to forward the packet using the same interface
  524          * as one we got the packet from, perhaps we should send a redirect
  525          * to sender to shortcut a hop.
  526          * Only send redirect if source is sending directly to us,
  527          * and if packet was not source routed (or has any options).
  528          * Also, don't send redirect if forwarding using a route
  529          * modified by a redirect.
  530          */
  531         if (ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
  532 #ifdef IPSEC
  533             !ipsecrt &&
  534 #endif
  535             (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
  536                 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
  537                         /*
  538                          * If the incoming interface is equal to the outgoing
  539                          * one, and the link attached to the interface is
  540                          * point-to-point, then it will be highly probable
  541                          * that a routing loop occurs. Thus, we immediately
  542                          * drop the packet and send an ICMPv6 error message.
  543                          *
  544                          * type/code is based on suggestion by Rich Draves.
  545                          * not sure if it is the best pick.
  546                          */
  547                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  548                                     ICMP6_DST_UNREACH_ADDR, 0);
  549                         m_freem(m);
  550                         return;
  551                 }
  552                 type = ND_REDIRECT;
  553         }
  554 
  555         /*
  556          * Check with the firewall...
  557          */
  558         if (ip6_fw_enable && ip6_fw_chk_ptr) {
  559                 u_short port = 0;
  560                 /* If ipfw says divert, we have to just drop packet */
  561                 if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) {
  562                         m_freem(m);
  563                         goto freecopy;
  564                 }
  565                 if (!m)
  566                         goto freecopy;
  567         }
  568 
  569         /*
  570          * Fake scoped addresses. Note that even link-local source or
  571          * destinaion can appear, if the originating node just sends the
  572          * packet to us (without address resolution for the destination).
  573          * Since both icmp6_error and icmp6_redirect_output fill the embedded
  574          * link identifiers, we can do this stuff after making a copy for
  575          * returning an error.
  576          */
  577         if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
  578                 /*
  579                  * See corresponding comments in ip6_output.
  580                  * XXX: but is it possible that ip6_forward() sends a packet
  581                  *      to a loopback interface? I don't think so, and thus
  582                  *      I bark here. (jinmei@kame.net)
  583                  * XXX: it is common to route invalid packets to loopback.
  584                  *      also, the codepath will be visited on use of ::1 in
  585                  *      rthdr. (itojun)
  586                  */
  587 #if 1
  588                 if (0)
  589 #else
  590                 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
  591 #endif
  592                 {
  593                         printf("ip6_forward: outgoing interface is loopback. "
  594                                "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
  595                                ip6_sprintf(&ip6->ip6_src),
  596                                ip6_sprintf(&ip6->ip6_dst),
  597                                ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
  598                                if_name(rt->rt_ifp));
  599                 }
  600 
  601                 /* we can just use rcvif in forwarding. */
  602                 origifp = m->m_pkthdr.rcvif;
  603         }
  604         else
  605                 origifp = rt->rt_ifp;
  606         /*
  607          * clear embedded scope identifiers if necessary.
  608          * in6_clearscope will touch the addresses only when necessary.
  609          */
  610         in6_clearscope(&ip6->ip6_src);
  611         in6_clearscope(&ip6->ip6_dst);
  612 
  613         /* Jump over all PFIL processing if hooks are not active. */
  614         if (inet6_pfil_hook.ph_busy_count == -1)
  615                 goto pass;
  616 
  617         /* Run through list of hooks for output packets. */
  618         error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL);
  619         if (error != 0)
  620                 goto senderr;
  621         if (m == NULL)
  622                 goto freecopy;
  623         ip6 = mtod(m, struct ip6_hdr *);
  624 
  625 pass:
  626         error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
  627         if (error) {
  628                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
  629                 ip6stat.ip6s_cantforward++;
  630         } else {
  631                 ip6stat.ip6s_forward++;
  632                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
  633                 if (type)
  634                         ip6stat.ip6s_redirectsent++;
  635                 else {
  636                         if (mcopy)
  637                                 goto freecopy;
  638                 }
  639         }
  640 
  641 senderr:
  642         if (mcopy == NULL)
  643                 return;
  644         switch (error) {
  645         case 0:
  646                 if (type == ND_REDIRECT) {
  647                         icmp6_redirect_output(mcopy, rt);
  648                         return;
  649                 }
  650                 goto freecopy;
  651 
  652         case EMSGSIZE:
  653                 /* xxx MTU is constant in PPP? */
  654                 goto freecopy;
  655 
  656         case ENOBUFS:
  657                 /* Tell source to slow down like source quench in IP? */
  658                 goto freecopy;
  659 
  660         case ENETUNREACH:       /* shouldn't happen, checked above */
  661         case EHOSTUNREACH:
  662         case ENETDOWN:
  663         case EHOSTDOWN:
  664         default:
  665                 type = ICMP6_DST_UNREACH;
  666                 code = ICMP6_DST_UNREACH_ADDR;
  667                 break;
  668         }
  669         icmp6_error(mcopy, type, code, 0);
  670         return;
  671 
  672  freecopy:
  673         m_freem(mcopy);
  674         return;
  675 }

Cache object: 90c550345b727ffdfba4233fadf99a6c


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