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/ip6_forward.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: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/10.1/sys/netinet6/ip6_forward.c 264224 2014-04-07 12:58:54Z ae $");
   34 
   35 #include "opt_inet.h"
   36 #include "opt_inet6.h"
   37 #include "opt_ipfw.h"
   38 #include "opt_ipsec.h"
   39 #include "opt_ipstealth.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/malloc.h>
   44 #include <sys/mbuf.h>
   45 #include <sys/domain.h>
   46 #include <sys/protosw.h>
   47 #include <sys/socket.h>
   48 #include <sys/errno.h>
   49 #include <sys/time.h>
   50 #include <sys/kernel.h>
   51 #include <sys/syslog.h>
   52 
   53 #include <net/if.h>
   54 #include <net/netisr.h>
   55 #include <net/route.h>
   56 #include <net/pfil.h>
   57 
   58 #include <netinet/in.h>
   59 #include <netinet/in_var.h>
   60 #include <netinet/in_systm.h>
   61 #include <netinet/ip.h>
   62 #include <netinet/ip_var.h>
   63 #include <netinet6/in6_var.h>
   64 #include <netinet/ip6.h>
   65 #include <netinet6/ip6_var.h>
   66 #include <netinet6/scope6_var.h>
   67 #include <netinet/icmp6.h>
   68 #include <netinet6/nd6.h>
   69 
   70 #include <netinet/in_pcb.h>
   71 
   72 #ifdef IPSEC
   73 #include <netipsec/ipsec.h>
   74 #include <netipsec/ipsec6.h>
   75 #include <netipsec/key.h>
   76 #endif /* IPSEC */
   77 
   78 #include <netinet6/ip6protosw.h>
   79 
   80 /*
   81  * Forward a packet.  If some error occurs return the sender
   82  * an icmp packet.  Note we can't always generate a meaningful
   83  * icmp message because icmp doesn't have a large enough repertoire
   84  * of codes and types.
   85  *
   86  * If not forwarding, just drop the packet.  This could be confusing
   87  * if ipforwarding was zero but some routing protocol was advancing
   88  * us as a gateway to somewhere.  However, we must let the routing
   89  * protocol deal with that.
   90  *
   91  */
   92 void
   93 ip6_forward(struct mbuf *m, int srcrt)
   94 {
   95         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
   96         struct sockaddr_in6 *dst = NULL;
   97         struct rtentry *rt = NULL;
   98         struct route_in6 rin6;
   99         int error, type = 0, code = 0;
  100         struct mbuf *mcopy = NULL;
  101         struct ifnet *origifp;  /* maybe unnecessary */
  102         u_int32_t inzone, outzone;
  103         struct in6_addr src_in6, dst_in6, odst;
  104 #ifdef IPSEC
  105         struct secpolicy *sp = NULL;
  106         int ipsecrt = 0;
  107 #endif
  108 #ifdef SCTP
  109         int sw_csum;
  110 #endif
  111         struct m_tag *fwd_tag;
  112         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  113 
  114 #ifdef IPSEC
  115         /*
  116          * Check AH/ESP integrity.
  117          */
  118         /*
  119          * Don't increment ip6s_cantforward because this is the check
  120          * before forwarding packet actually.
  121          */
  122         if (ipsec6_in_reject(m, NULL)) {
  123                 IPSEC6STAT_INC(ips_in_polvio);
  124                 m_freem(m);
  125                 return;
  126         }
  127 #endif /* IPSEC */
  128 
  129         /*
  130          * Do not forward packets to multicast destination (should be handled
  131          * by ip6_mforward().
  132          * Do not forward packets with unspecified source.  It was discussed
  133          * in July 2000, on the ipngwg mailing list.
  134          */
  135         if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
  136             IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
  137             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
  138                 IP6STAT_INC(ip6s_cantforward);
  139                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
  140                 if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
  141                         V_ip6_log_time = time_uptime;
  142                         log(LOG_DEBUG,
  143                             "cannot forward "
  144                             "from %s to %s nxt %d received on %s\n",
  145                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
  146                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  147                             ip6->ip6_nxt,
  148                             if_name(m->m_pkthdr.rcvif));
  149                 }
  150                 m_freem(m);
  151                 return;
  152         }
  153 
  154 #ifdef IPSTEALTH
  155         if (!V_ip6stealth) {
  156 #endif
  157         if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
  158                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
  159                 icmp6_error(m, ICMP6_TIME_EXCEEDED,
  160                                 ICMP6_TIME_EXCEED_TRANSIT, 0);
  161                 return;
  162         }
  163         ip6->ip6_hlim -= IPV6_HLIMDEC;
  164 
  165 #ifdef IPSTEALTH
  166         }
  167 #endif
  168 
  169         /*
  170          * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
  171          * size of IPv6 + ICMPv6 headers) bytes of the packet in case
  172          * we need to generate an ICMP6 message to the src.
  173          * Thanks to M_EXT, in most cases copy will not occur.
  174          *
  175          * It is important to save it before IPsec processing as IPsec
  176          * processing may modify the mbuf.
  177          */
  178         mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
  179 
  180 #ifdef IPSEC
  181         /* get a security policy for this packet */
  182         sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
  183             IP_FORWARDING, &error);
  184         if (sp == NULL) {
  185                 IPSEC6STAT_INC(ips_out_inval);
  186                 IP6STAT_INC(ip6s_cantforward);
  187                 if (mcopy) {
  188 #if 0
  189                         /* XXX: what icmp ? */
  190 #else
  191                         m_freem(mcopy);
  192 #endif
  193                 }
  194                 m_freem(m);
  195                 return;
  196         }
  197 
  198         error = 0;
  199 
  200         /* check policy */
  201         switch (sp->policy) {
  202         case IPSEC_POLICY_DISCARD:
  203                 /*
  204                  * This packet is just discarded.
  205                  */
  206                 IPSEC6STAT_INC(ips_out_polvio);
  207                 IP6STAT_INC(ip6s_cantforward);
  208                 KEY_FREESP(&sp);
  209                 if (mcopy) {
  210 #if 0
  211                         /* XXX: what icmp ? */
  212 #else
  213                         m_freem(mcopy);
  214 #endif
  215                 }
  216                 m_freem(m);
  217                 return;
  218 
  219         case IPSEC_POLICY_BYPASS:
  220         case IPSEC_POLICY_NONE:
  221                 /* no need to do IPsec. */
  222                 KEY_FREESP(&sp);
  223                 goto skip_ipsec;
  224 
  225         case IPSEC_POLICY_IPSEC:
  226                 if (sp->req == NULL) {
  227                         /* XXX should be panic ? */
  228                         printf("ip6_forward: No IPsec request specified.\n");
  229                         IP6STAT_INC(ip6s_cantforward);
  230                         KEY_FREESP(&sp);
  231                         if (mcopy) {
  232 #if 0
  233                                 /* XXX: what icmp ? */
  234 #else
  235                                 m_freem(mcopy);
  236 #endif
  237                         }
  238                         m_freem(m);
  239                         return;
  240                 }
  241                 /* do IPsec */
  242                 break;
  243 
  244         case IPSEC_POLICY_ENTRUST:
  245         default:
  246                 /* should be panic ?? */
  247                 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
  248                 KEY_FREESP(&sp);
  249                 goto skip_ipsec;
  250         }
  251 
  252     {
  253         struct ipsecrequest *isr = NULL;
  254         struct ipsec_output_state state;
  255 
  256         /*
  257          * when the kernel forwards a packet, it is not proper to apply
  258          * IPsec transport mode to the packet is not proper.  this check
  259          * avoid from this.
  260          * at present, if there is even a transport mode SA request in the
  261          * security policy, the kernel does not apply IPsec to the packet.
  262          * this check is not enough because the following case is valid.
  263          *      ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
  264          */
  265         for (isr = sp->req; isr; isr = isr->next) {
  266                 if (isr->saidx.mode == IPSEC_MODE_ANY)
  267                         goto doipsectunnel;
  268                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  269                         goto doipsectunnel;
  270         }
  271 
  272         /*
  273          * if there's no need for tunnel mode IPsec, skip.
  274          */
  275         if (!isr)
  276                 goto skip_ipsec;
  277 
  278     doipsectunnel:
  279         /*
  280          * All the extension headers will become inaccessible
  281          * (since they can be encrypted).
  282          * Don't panic, we need no more updates to extension headers
  283          * on inner IPv6 packet (since they are now encapsulated).
  284          *
  285          * IPv6 [ESP|AH] IPv6 [extension headers] payload
  286          */
  287         bzero(&state, sizeof(state));
  288         state.m = m;
  289         state.ro = NULL;        /* update at ipsec6_output_tunnel() */
  290         state.dst = NULL;       /* update at ipsec6_output_tunnel() */
  291 
  292         error = ipsec6_output_tunnel(&state, sp, 0);
  293 
  294         m = state.m;
  295         KEY_FREESP(&sp);
  296 
  297         if (error) {
  298                 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
  299                 switch (error) {
  300                 case EHOSTUNREACH:
  301                 case ENETUNREACH:
  302                 case EMSGSIZE:
  303                 case ENOBUFS:
  304                 case ENOMEM:
  305                         break;
  306                 default:
  307                         printf("ip6_output (ipsec): error code %d\n", error);
  308                         /* FALLTHROUGH */
  309                 case ENOENT:
  310                         /* don't show these error codes to the user */
  311                         break;
  312                 }
  313                 IP6STAT_INC(ip6s_cantforward);
  314                 if (mcopy) {
  315 #if 0
  316                         /* XXX: what icmp ? */
  317 #else
  318                         m_freem(mcopy);
  319 #endif
  320                 }
  321                 m_freem(m);
  322                 return;
  323         } else {
  324                 /*
  325                  * In the FAST IPSec case we have already
  326                  * re-injected the packet and it has been freed
  327                  * by the ipsec_done() function.  So, just clean
  328                  * up after ourselves.
  329                  */
  330                 m = NULL;
  331                 goto freecopy;
  332         }
  333 
  334         if ((m != NULL) && (ip6 != mtod(m, struct ip6_hdr *)) ){
  335                 /*
  336                  * now tunnel mode headers are added.  we are originating
  337                  * packet instead of forwarding the packet.
  338                  */
  339                 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL,
  340                     NULL);
  341                 goto freecopy;
  342         }
  343 
  344         /* adjust pointer */
  345         dst = (struct sockaddr_in6 *)state.dst;
  346         rt = state.ro ? state.ro->ro_rt : NULL;
  347         if (dst != NULL && rt != NULL)
  348                 ipsecrt = 1;
  349     }
  350         if (ipsecrt)
  351                 goto skip_routing;
  352 skip_ipsec:
  353 #endif
  354 again:
  355         bzero(&rin6, sizeof(struct route_in6));
  356         dst = (struct sockaddr_in6 *)&rin6.ro_dst;
  357         dst->sin6_len = sizeof(struct sockaddr_in6);
  358         dst->sin6_family = AF_INET6;
  359         dst->sin6_addr = ip6->ip6_dst;
  360 again2:
  361         rin6.ro_rt = in6_rtalloc1((struct sockaddr *)dst, 0, 0, M_GETFIB(m));
  362         if (rin6.ro_rt != NULL)
  363                 RT_UNLOCK(rin6.ro_rt);
  364         else {
  365                 IP6STAT_INC(ip6s_noroute);
  366                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
  367                 if (mcopy) {
  368                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  369                         ICMP6_DST_UNREACH_NOROUTE, 0);
  370                 }
  371                 goto bad;
  372         }
  373         rt = rin6.ro_rt;
  374 #ifdef IPSEC
  375 skip_routing:
  376 #endif
  377 
  378         /*
  379          * Source scope check: if a packet can't be delivered to its
  380          * destination for the reason that the destination is beyond the scope
  381          * of the source address, discard the packet and return an icmp6
  382          * destination unreachable error with Code 2 (beyond scope of source
  383          * address).  We use a local copy of ip6_src, since in6_setscope()
  384          * will possibly modify its first argument.
  385          * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
  386          */
  387         src_in6 = ip6->ip6_src;
  388         if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
  389                 /* XXX: this should not happen */
  390                 IP6STAT_INC(ip6s_cantforward);
  391                 IP6STAT_INC(ip6s_badscope);
  392                 goto bad;
  393         }
  394         if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
  395                 IP6STAT_INC(ip6s_cantforward);
  396                 IP6STAT_INC(ip6s_badscope);
  397                 goto bad;
  398         }
  399         if (inzone != outzone
  400 #ifdef IPSEC
  401             && !ipsecrt
  402 #endif
  403             ) {
  404                 IP6STAT_INC(ip6s_cantforward);
  405                 IP6STAT_INC(ip6s_badscope);
  406                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
  407 
  408                 if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
  409                         V_ip6_log_time = time_uptime;
  410                         log(LOG_DEBUG,
  411                             "cannot forward "
  412                             "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
  413                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
  414                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  415                             ip6->ip6_nxt,
  416                             if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
  417                 }
  418                 if (mcopy)
  419                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  420                                     ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
  421                 goto bad;
  422         }
  423 
  424         /*
  425          * Destination scope check: if a packet is going to break the scope
  426          * zone of packet's destination address, discard it.  This case should
  427          * usually be prevented by appropriately-configured routing table, but
  428          * we need an explicit check because we may mistakenly forward the
  429          * packet to a different zone by (e.g.) a default route.
  430          */
  431         dst_in6 = ip6->ip6_dst;
  432         if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
  433             in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
  434             inzone != outzone) {
  435                 IP6STAT_INC(ip6s_cantforward);
  436                 IP6STAT_INC(ip6s_badscope);
  437                 goto bad;
  438         }
  439 
  440         if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
  441                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
  442                 if (mcopy) {
  443                         u_long mtu;
  444 #ifdef IPSEC
  445                         struct secpolicy *sp;
  446                         int ipsecerror;
  447                         size_t ipsechdrsiz;
  448 #endif /* IPSEC */
  449 
  450                         mtu = IN6_LINKMTU(rt->rt_ifp);
  451 #ifdef IPSEC
  452                         /*
  453                          * When we do IPsec tunnel ingress, we need to play
  454                          * with the link value (decrement IPsec header size
  455                          * from mtu value).  The code is much simpler than v4
  456                          * case, as we have the outgoing interface for
  457                          * encapsulated packet as "rt->rt_ifp".
  458                          */
  459                         sp = ipsec_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
  460                                 IP_FORWARDING, &ipsecerror);
  461                         if (sp) {
  462                                 ipsechdrsiz = ipsec_hdrsiz(mcopy,
  463                                         IPSEC_DIR_OUTBOUND, NULL);
  464                                 if (ipsechdrsiz < mtu)
  465                                         mtu -= ipsechdrsiz;
  466                         }
  467 
  468                         /*
  469                          * if mtu becomes less than minimum MTU,
  470                          * tell minimum MTU (and I'll need to fragment it).
  471                          */
  472                         if (mtu < IPV6_MMTU)
  473                                 mtu = IPV6_MMTU;
  474 #endif /* IPSEC */
  475                         icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
  476                 }
  477                 goto bad;
  478         }
  479 
  480         if (rt->rt_flags & RTF_GATEWAY)
  481                 dst = (struct sockaddr_in6 *)rt->rt_gateway;
  482 
  483         /*
  484          * If we are to forward the packet using the same interface
  485          * as one we got the packet from, perhaps we should send a redirect
  486          * to sender to shortcut a hop.
  487          * Only send redirect if source is sending directly to us,
  488          * and if packet was not source routed (or has any options).
  489          * Also, don't send redirect if forwarding using a route
  490          * modified by a redirect.
  491          */
  492         if (V_ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
  493 #ifdef IPSEC
  494             !ipsecrt &&
  495 #endif /* IPSEC */
  496             (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
  497                 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
  498                         /*
  499                          * If the incoming interface is equal to the outgoing
  500                          * one, and the link attached to the interface is
  501                          * point-to-point, then it will be highly probable
  502                          * that a routing loop occurs. Thus, we immediately
  503                          * drop the packet and send an ICMPv6 error message.
  504                          *
  505                          * type/code is based on suggestion by Rich Draves.
  506                          * not sure if it is the best pick.
  507                          */
  508                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  509                                     ICMP6_DST_UNREACH_ADDR, 0);
  510                         goto bad;
  511                 }
  512                 type = ND_REDIRECT;
  513         }
  514 
  515         /*
  516          * Fake scoped addresses. Note that even link-local source or
  517          * destinaion can appear, if the originating node just sends the
  518          * packet to us (without address resolution for the destination).
  519          * Since both icmp6_error and icmp6_redirect_output fill the embedded
  520          * link identifiers, we can do this stuff after making a copy for
  521          * returning an error.
  522          */
  523         if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
  524                 /*
  525                  * See corresponding comments in ip6_output.
  526                  * XXX: but is it possible that ip6_forward() sends a packet
  527                  *      to a loopback interface? I don't think so, and thus
  528                  *      I bark here. (jinmei@kame.net)
  529                  * XXX: it is common to route invalid packets to loopback.
  530                  *      also, the codepath will be visited on use of ::1 in
  531                  *      rthdr. (itojun)
  532                  */
  533 #if 1
  534                 if (0)
  535 #else
  536                 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
  537 #endif
  538                 {
  539                         printf("ip6_forward: outgoing interface is loopback. "
  540                                "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
  541                                ip6_sprintf(ip6bufs, &ip6->ip6_src),
  542                                ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  543                                ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
  544                                if_name(rt->rt_ifp));
  545                 }
  546 
  547                 /* we can just use rcvif in forwarding. */
  548                 origifp = m->m_pkthdr.rcvif;
  549         }
  550         else
  551                 origifp = rt->rt_ifp;
  552         /*
  553          * clear embedded scope identifiers if necessary.
  554          * in6_clearscope will touch the addresses only when necessary.
  555          */
  556         in6_clearscope(&ip6->ip6_src);
  557         in6_clearscope(&ip6->ip6_dst);
  558 
  559         /* Jump over all PFIL processing if hooks are not active. */
  560         if (!PFIL_HOOKED(&V_inet6_pfil_hook))
  561                 goto pass;
  562 
  563         odst = ip6->ip6_dst;
  564         /* Run through list of hooks for output packets. */
  565         error = pfil_run_hooks(&V_inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL);
  566         if (error != 0 || m == NULL)
  567                 goto freecopy;          /* consumed by filter */
  568         ip6 = mtod(m, struct ip6_hdr *);
  569 
  570         /* See if destination IP address was changed by packet filter. */
  571         if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
  572                 m->m_flags |= M_SKIP_FIREWALL;
  573                 /* If destination is now ourself drop to ip6_input(). */
  574                 if (in6_localip(&ip6->ip6_dst)) {
  575                         m->m_flags |= M_FASTFWD_OURS;
  576                         if (m->m_pkthdr.rcvif == NULL)
  577                                 m->m_pkthdr.rcvif = V_loif;
  578                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
  579                                 m->m_pkthdr.csum_flags |=
  580                                     CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
  581                                 m->m_pkthdr.csum_data = 0xffff;
  582                         }
  583 #ifdef SCTP
  584                         if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
  585                                 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
  586 #endif
  587                         error = netisr_queue(NETISR_IPV6, m);
  588                         goto out;
  589                 } else
  590                         goto again;     /* Redo the routing table lookup. */
  591         }
  592 
  593         /* See if local, if yes, send it to netisr. */
  594         if (m->m_flags & M_FASTFWD_OURS) {
  595                 if (m->m_pkthdr.rcvif == NULL)
  596                         m->m_pkthdr.rcvif = V_loif;
  597                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
  598                         m->m_pkthdr.csum_flags |=
  599                             CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
  600                         m->m_pkthdr.csum_data = 0xffff;
  601                 }
  602 #ifdef SCTP
  603                 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
  604                         m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
  605 #endif
  606                 error = netisr_queue(NETISR_IPV6, m);
  607                 goto out;
  608         }
  609         /* Or forward to some other address? */
  610         if ((m->m_flags & M_IP6_NEXTHOP) &&
  611             (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
  612                 dst = (struct sockaddr_in6 *)&rin6.ro_dst;
  613                 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in6));
  614                 m->m_flags |= M_SKIP_FIREWALL;
  615                 m->m_flags &= ~M_IP6_NEXTHOP;
  616                 m_tag_delete(m, fwd_tag);
  617                 goto again2;
  618         }
  619 
  620 pass:
  621         error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
  622         if (error) {
  623                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
  624                 IP6STAT_INC(ip6s_cantforward);
  625         } else {
  626                 IP6STAT_INC(ip6s_forward);
  627                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
  628                 if (type)
  629                         IP6STAT_INC(ip6s_redirectsent);
  630                 else {
  631                         if (mcopy)
  632                                 goto freecopy;
  633                 }
  634         }
  635 
  636         if (mcopy == NULL)
  637                 goto out;
  638         switch (error) {
  639         case 0:
  640                 if (type == ND_REDIRECT) {
  641                         icmp6_redirect_output(mcopy, rt);
  642                         goto out;
  643                 }
  644                 goto freecopy;
  645 
  646         case EMSGSIZE:
  647                 /* xxx MTU is constant in PPP? */
  648                 goto freecopy;
  649 
  650         case ENOBUFS:
  651                 /* Tell source to slow down like source quench in IP? */
  652                 goto freecopy;
  653 
  654         case ENETUNREACH:       /* shouldn't happen, checked above */
  655         case EHOSTUNREACH:
  656         case ENETDOWN:
  657         case EHOSTDOWN:
  658         default:
  659                 type = ICMP6_DST_UNREACH;
  660                 code = ICMP6_DST_UNREACH_ADDR;
  661                 break;
  662         }
  663         icmp6_error(mcopy, type, code, 0);
  664         goto out;
  665 
  666  freecopy:
  667         m_freem(mcopy);
  668         goto out;
  669 bad:
  670         m_freem(m);
  671 out:
  672         if (rt != NULL
  673 #ifdef IPSEC
  674             && !ipsecrt
  675 #endif
  676             )
  677                 RTFREE(rt);
  678 }

Cache object: 33ec64745ca2d62f2d935c72fd5915c6


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