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


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netinet6/ip6_forward.c

Version: -  FREEBSD  -  FREEBSD11  -  FREEBSD10  -  FREEBSD9  -  FREEBSD92  -  FREEBSD91  -  FREEBSD90  -  FREEBSD8  -  FREEBSD82  -  FREEBSD81  -  FREEBSD80  -  FREEBSD7  -  FREEBSD74  -  FREEBSD73  -  FREEBSD72  -  FREEBSD71  -  FREEBSD70  -  FREEBSD6  -  FREEBSD64  -  FREEBSD63  -  FREEBSD62  -  FREEBSD61  -  FREEBSD60  -  FREEBSD5  -  FREEBSD55  -  FREEBSD54  -  FREEBSD53  -  FREEBSD52  -  FREEBSD51  -  FREEBSD50  -  FREEBSD4  -  FREEBSD3  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    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("$FreeBSD$");
   34 
   35 #include "opt_inet.h"
   36 #include "opt_inet6.h"
   37 #include "opt_ipsec.h"
   38 #include "opt_ipstealth.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/malloc.h>
   43 #include <sys/mbuf.h>
   44 #include <sys/domain.h>
   45 #include <sys/protosw.h>
   46 #include <sys/socket.h>
   47 #include <sys/errno.h>
   48 #include <sys/time.h>
   49 #include <sys/kernel.h>
   50 #include <sys/syslog.h>
   51 
   52 #include <net/if.h>
   53 #include <net/route.h>
   54 #include <net/pfil.h>
   55 
   56 #include <netinet/in.h>
   57 #include <netinet/in_var.h>
   58 #include <netinet/in_systm.h>
   59 #include <netinet/ip.h>
   60 #include <netinet/ip_var.h>
   61 #include <netinet6/in6_var.h>
   62 #include <netinet/ip6.h>
   63 #include <netinet6/ip6_var.h>
   64 #include <netinet6/scope6_var.h>
   65 #include <netinet/icmp6.h>
   66 #include <netinet6/nd6.h>
   67 
   68 #include <netinet/in_pcb.h>
   69 
   70 #ifdef IPSEC
   71 #include <netipsec/ipsec.h>
   72 #include <netipsec/ipsec6.h>
   73 #include <netipsec/key.h>
   74 #endif /* IPSEC */
   75 
   76 #include <netinet6/ip6protosw.h>
   77 
   78 struct  route_in6 ip6_forward_rt;
   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         int error, type = 0, code = 0;
   99         struct mbuf *mcopy = NULL;
  100         struct ifnet *origifp;  /* maybe unnecessary */
  101         u_int32_t inzone, outzone;
  102         struct in6_addr src_in6, dst_in6;
  103 #ifdef IPSEC
  104         struct secpolicy *sp = NULL;
  105         int ipsecrt = 0;
  106 #endif
  107         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
  108 
  109         GIANT_REQUIRED; /* XXX bz: ip6_forward_rt */
  110 
  111 #ifdef IPSEC
  112         /*
  113          * Check AH/ESP integrity.
  114          */
  115         /*
  116          * Don't increment ip6s_cantforward because this is the check
  117          * before forwarding packet actually.
  118          */
  119         if (ipsec6_in_reject(m, NULL)) {
  120                 ipsec6stat.in_polvio++;
  121                 m_freem(m);
  122                 return;
  123         }
  124 #endif /* IPSEC */
  125 
  126         /*
  127          * Do not forward packets to multicast destination (should be handled
  128          * by ip6_mforward().
  129          * Do not forward packets with unspecified source.  It was discussed
  130          * in July 2000, on the ipngwg mailing list.
  131          */
  132         if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
  133             IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
  134             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
  135                 ip6stat.ip6s_cantforward++;
  136                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
  137                 if (ip6_log_time + ip6_log_interval < time_second) {
  138                         ip6_log_time = time_second;
  139                         log(LOG_DEBUG,
  140                             "cannot forward "
  141                             "from %s to %s nxt %d received on %s\n",
  142                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
  143                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  144                             ip6->ip6_nxt,
  145                             if_name(m->m_pkthdr.rcvif));
  146                 }
  147                 m_freem(m);
  148                 return;
  149         }
  150 
  151 #ifdef IPSTEALTH
  152         if (!ip6stealth) {
  153 #endif
  154         if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
  155                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
  156                 icmp6_error(m, ICMP6_TIME_EXCEEDED,
  157                                 ICMP6_TIME_EXCEED_TRANSIT, 0);
  158                 return;
  159         }
  160         ip6->ip6_hlim -= IPV6_HLIMDEC;
  161 
  162 #ifdef IPSTEALTH
  163         }
  164 #endif
  165 
  166         /*
  167          * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
  168          * size of IPv6 + ICMPv6 headers) bytes of the packet in case
  169          * we need to generate an ICMP6 message to the src.
  170          * Thanks to M_EXT, in most cases copy will not occur.
  171          *
  172          * It is important to save it before IPsec processing as IPsec
  173          * processing may modify the mbuf.
  174          */
  175         mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
  176 
  177 #ifdef IPSEC
  178         /* get a security policy for this packet */
  179         sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
  180             IP_FORWARDING, &error);
  181         if (sp == NULL) {
  182                 ipsec6stat.out_inval++;
  183                 ip6stat.ip6s_cantforward++;
  184                 if (mcopy) {
  185 #if 0
  186                         /* XXX: what icmp ? */
  187 #else
  188                         m_freem(mcopy);
  189 #endif
  190                 }
  191                 m_freem(m);
  192                 return;
  193         }
  194 
  195         error = 0;
  196 
  197         /* check policy */
  198         switch (sp->policy) {
  199         case IPSEC_POLICY_DISCARD:
  200                 /*
  201                  * This packet is just discarded.
  202                  */
  203                 ipsec6stat.out_polvio++;
  204                 ip6stat.ip6s_cantforward++;
  205                 KEY_FREESP(&sp);
  206                 if (mcopy) {
  207 #if 0
  208                         /* XXX: what icmp ? */
  209 #else
  210                         m_freem(mcopy);
  211 #endif
  212                 }
  213                 m_freem(m);
  214                 return;
  215 
  216         case IPSEC_POLICY_BYPASS:
  217         case IPSEC_POLICY_NONE:
  218                 /* no need to do IPsec. */
  219                 KEY_FREESP(&sp);
  220                 goto skip_ipsec;
  221 
  222         case IPSEC_POLICY_IPSEC:
  223                 if (sp->req == NULL) {
  224                         /* XXX should be panic ? */
  225                         printf("ip6_forward: No IPsec request specified.\n");
  226                         ip6stat.ip6s_cantforward++;
  227                         KEY_FREESP(&sp);
  228                         if (mcopy) {
  229 #if 0
  230                                 /* XXX: what icmp ? */
  231 #else
  232                                 m_freem(mcopy);
  233 #endif
  234                         }
  235                         m_freem(m);
  236                         return;
  237                 }
  238                 /* do IPsec */
  239                 break;
  240 
  241         case IPSEC_POLICY_ENTRUST:
  242         default:
  243                 /* should be panic ?? */
  244                 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
  245                 KEY_FREESP(&sp);
  246                 goto skip_ipsec;
  247         }
  248 
  249     {
  250         struct ipsecrequest *isr = NULL;
  251         struct ipsec_output_state state;
  252 
  253         /*
  254          * when the kernel forwards a packet, it is not proper to apply
  255          * IPsec transport mode to the packet is not proper.  this check
  256          * avoid from this.
  257          * at present, if there is even a transport mode SA request in the
  258          * security policy, the kernel does not apply IPsec to the packet.
  259          * this check is not enough because the following case is valid.
  260          *      ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
  261          */
  262         for (isr = sp->req; isr; isr = isr->next) {
  263                 if (isr->saidx.mode == IPSEC_MODE_ANY)
  264                         goto doipsectunnel;
  265                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
  266                         goto doipsectunnel;
  267         }
  268 
  269         /*
  270          * if there's no need for tunnel mode IPsec, skip.
  271          */
  272         if (!isr)
  273                 goto skip_ipsec;
  274 
  275     doipsectunnel:
  276         /*
  277          * All the extension headers will become inaccessible
  278          * (since they can be encrypted).
  279          * Don't panic, we need no more updates to extension headers
  280          * on inner IPv6 packet (since they are now encapsulated).
  281          *
  282          * IPv6 [ESP|AH] IPv6 [extension headers] payload
  283          */
  284         bzero(&state, sizeof(state));
  285         state.m = m;
  286         state.ro = NULL;        /* update at ipsec6_output_tunnel() */
  287         state.dst = NULL;       /* update at ipsec6_output_tunnel() */
  288 
  289         error = ipsec6_output_tunnel(&state, sp, 0);
  290 
  291         m = state.m;
  292         KEY_FREESP(&sp);
  293 
  294         if (error) {
  295                 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
  296                 switch (error) {
  297                 case EHOSTUNREACH:
  298                 case ENETUNREACH:
  299                 case EMSGSIZE:
  300                 case ENOBUFS:
  301                 case ENOMEM:
  302                         break;
  303                 default:
  304                         printf("ip6_output (ipsec): error code %d\n", error);
  305                         /* FALLTHROUGH */
  306                 case ENOENT:
  307                         /* don't show these error codes to the user */
  308                         break;
  309                 }
  310                 ip6stat.ip6s_cantforward++;
  311                 if (mcopy) {
  312 #if 0
  313                         /* XXX: what icmp ? */
  314 #else
  315                         m_freem(mcopy);
  316 #endif
  317                 }
  318                 m_freem(m);
  319                 return;
  320         } else {
  321                 /*
  322                  * In the FAST IPSec case we have already
  323                  * re-injected the packet and it has been freed
  324                  * by the ipsec_done() function.  So, just clean
  325                  * up after ourselves.
  326                  */
  327                 m = NULL;
  328                 goto freecopy;
  329         }
  330 
  331         if ((m != NULL) && (ip6 != mtod(m, struct ip6_hdr *)) ){
  332                 /*
  333                  * now tunnel mode headers are added.  we are originating
  334                  * packet instead of forwarding the packet.
  335                  */
  336                 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL,
  337                     NULL);
  338                 goto freecopy;
  339         }
  340 
  341         /* adjust pointer */
  342         dst = (struct sockaddr_in6 *)state.dst;
  343         rt = state.ro ? state.ro->ro_rt : NULL;
  344         if (dst != NULL && rt != NULL)
  345                 ipsecrt = 1;
  346     }
  347     skip_ipsec:
  348 #endif /* IPSEC */
  349 
  350 #ifdef IPSEC
  351         if (ipsecrt)
  352                 goto skip_routing;
  353 #endif
  354 
  355         dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
  356         if (!srcrt) {
  357                 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */
  358                 if (ip6_forward_rt.ro_rt == 0 ||
  359                     (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) {
  360                         if (ip6_forward_rt.ro_rt) {
  361                                 RTFREE(ip6_forward_rt.ro_rt);
  362                                 ip6_forward_rt.ro_rt = 0;
  363                         }
  364 
  365                         /* this probably fails but give it a try again */
  366                         rtalloc((struct route *)&ip6_forward_rt);
  367                 }
  368 
  369                 if (ip6_forward_rt.ro_rt == 0) {
  370                         ip6stat.ip6s_noroute++;
  371                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
  372                         if (mcopy) {
  373                                 icmp6_error(mcopy, ICMP6_DST_UNREACH,
  374                                             ICMP6_DST_UNREACH_NOROUTE, 0);
  375                         }
  376                         m_freem(m);
  377                         return;
  378                 }
  379         } else if ((rt = ip6_forward_rt.ro_rt) == 0 ||
  380                    !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) {
  381                 if (ip6_forward_rt.ro_rt) {
  382                         RTFREE(ip6_forward_rt.ro_rt);
  383                         ip6_forward_rt.ro_rt = 0;
  384                 }
  385                 bzero(dst, sizeof(*dst));
  386                 dst->sin6_len = sizeof(struct sockaddr_in6);
  387                 dst->sin6_family = AF_INET6;
  388                 dst->sin6_addr = ip6->ip6_dst;
  389 
  390                 rtalloc((struct route *)&ip6_forward_rt);
  391                 if (ip6_forward_rt.ro_rt == 0) {
  392                         ip6stat.ip6s_noroute++;
  393                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
  394                         if (mcopy) {
  395                                 icmp6_error(mcopy, ICMP6_DST_UNREACH,
  396                                             ICMP6_DST_UNREACH_NOROUTE, 0);
  397                         }
  398                         m_freem(m);
  399                         return;
  400                 }
  401         }
  402         rt = ip6_forward_rt.ro_rt;
  403 #ifdef IPSEC
  404     skip_routing:;
  405 #endif
  406 
  407         /*
  408          * Source scope check: if a packet can't be delivered to its
  409          * destination for the reason that the destination is beyond the scope
  410          * of the source address, discard the packet and return an icmp6
  411          * destination unreachable error with Code 2 (beyond scope of source
  412          * address).  We use a local copy of ip6_src, since in6_setscope()
  413          * will possibly modify its first argument.
  414          * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
  415          */
  416         src_in6 = ip6->ip6_src;
  417         if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
  418                 /* XXX: this should not happen */
  419                 ip6stat.ip6s_cantforward++;
  420                 ip6stat.ip6s_badscope++;
  421                 m_freem(m);
  422                 return;
  423         }
  424         if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
  425                 ip6stat.ip6s_cantforward++;
  426                 ip6stat.ip6s_badscope++;
  427                 m_freem(m);
  428                 return;
  429         }
  430         if (inzone != outzone
  431 #ifdef IPSEC
  432             && !ipsecrt
  433 #endif
  434             ) {
  435                 ip6stat.ip6s_cantforward++;
  436                 ip6stat.ip6s_badscope++;
  437                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
  438 
  439                 if (ip6_log_time + ip6_log_interval < time_second) {
  440                         ip6_log_time = time_second;
  441                         log(LOG_DEBUG,
  442                             "cannot forward "
  443                             "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
  444                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
  445                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  446                             ip6->ip6_nxt,
  447                             if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
  448                 }
  449                 if (mcopy)
  450                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  451                                     ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
  452                 m_freem(m);
  453                 return;
  454         }
  455 
  456         /*
  457          * Destination scope check: if a packet is going to break the scope
  458          * zone of packet's destination address, discard it.  This case should
  459          * usually be prevented by appropriately-configured routing table, but
  460          * we need an explicit check because we may mistakenly forward the
  461          * packet to a different zone by (e.g.) a default route.
  462          */
  463         dst_in6 = ip6->ip6_dst;
  464         if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
  465             in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
  466             inzone != outzone) {
  467                 ip6stat.ip6s_cantforward++;
  468                 ip6stat.ip6s_badscope++;
  469                 m_freem(m);
  470                 return;
  471         }
  472 
  473         if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
  474                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
  475                 if (mcopy) {
  476                         u_long mtu;
  477 #ifdef IPSEC
  478                         struct secpolicy *sp;
  479                         int ipsecerror;
  480                         size_t ipsechdrsiz;
  481 #endif /* IPSEC */
  482 
  483                         mtu = IN6_LINKMTU(rt->rt_ifp);
  484 #ifdef IPSEC
  485                         /*
  486                          * When we do IPsec tunnel ingress, we need to play
  487                          * with the link value (decrement IPsec header size
  488                          * from mtu value).  The code is much simpler than v4
  489                          * case, as we have the outgoing interface for
  490                          * encapsulated packet as "rt->rt_ifp".
  491                          */
  492                         sp = ipsec_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
  493                                 IP_FORWARDING, &ipsecerror);
  494                         if (sp) {
  495                                 ipsechdrsiz = ipsec6_hdrsiz(mcopy,
  496                                         IPSEC_DIR_OUTBOUND, NULL);
  497                                 if (ipsechdrsiz < mtu)
  498                                         mtu -= ipsechdrsiz;
  499                         }
  500 
  501                         /*
  502                          * if mtu becomes less than minimum MTU,
  503                          * tell minimum MTU (and I'll need to fragment it).
  504                          */
  505                         if (mtu < IPV6_MMTU)
  506                                 mtu = IPV6_MMTU;
  507 #endif /* IPSEC */
  508                         icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
  509                 }
  510                 m_freem(m);
  511                 return;
  512         }
  513 
  514         if (rt->rt_flags & RTF_GATEWAY)
  515                 dst = (struct sockaddr_in6 *)rt->rt_gateway;
  516 
  517         /*
  518          * If we are to forward the packet using the same interface
  519          * as one we got the packet from, perhaps we should send a redirect
  520          * to sender to shortcut a hop.
  521          * Only send redirect if source is sending directly to us,
  522          * and if packet was not source routed (or has any options).
  523          * Also, don't send redirect if forwarding using a route
  524          * modified by a redirect.
  525          */
  526         if (ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
  527 #ifdef IPSEC
  528             !ipsecrt &&
  529 #endif /* IPSEC */
  530             (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
  531                 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
  532                         /*
  533                          * If the incoming interface is equal to the outgoing
  534                          * one, and the link attached to the interface is
  535                          * point-to-point, then it will be highly probable
  536                          * that a routing loop occurs. Thus, we immediately
  537                          * drop the packet and send an ICMPv6 error message.
  538                          *
  539                          * type/code is based on suggestion by Rich Draves.
  540                          * not sure if it is the best pick.
  541                          */
  542                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
  543                                     ICMP6_DST_UNREACH_ADDR, 0);
  544                         m_freem(m);
  545                         return;
  546                 }
  547                 type = ND_REDIRECT;
  548         }
  549 
  550         /*
  551          * Fake scoped addresses. Note that even link-local source or
  552          * destinaion can appear, if the originating node just sends the
  553          * packet to us (without address resolution for the destination).
  554          * Since both icmp6_error and icmp6_redirect_output fill the embedded
  555          * link identifiers, we can do this stuff after making a copy for
  556          * returning an error.
  557          */
  558         if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
  559                 /*
  560                  * See corresponding comments in ip6_output.
  561                  * XXX: but is it possible that ip6_forward() sends a packet
  562                  *      to a loopback interface? I don't think so, and thus
  563                  *      I bark here. (jinmei@kame.net)
  564                  * XXX: it is common to route invalid packets to loopback.
  565                  *      also, the codepath will be visited on use of ::1 in
  566                  *      rthdr. (itojun)
  567                  */
  568 #if 1
  569                 if (0)
  570 #else
  571                 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
  572 #endif
  573                 {
  574                         printf("ip6_forward: outgoing interface is loopback. "
  575                                "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
  576                                ip6_sprintf(ip6bufs, &ip6->ip6_src),
  577                                ip6_sprintf(ip6bufd, &ip6->ip6_dst),
  578                                ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
  579                                if_name(rt->rt_ifp));
  580                 }
  581 
  582                 /* we can just use rcvif in forwarding. */
  583                 origifp = m->m_pkthdr.rcvif;
  584         }
  585         else
  586                 origifp = rt->rt_ifp;
  587         /*
  588          * clear embedded scope identifiers if necessary.
  589          * in6_clearscope will touch the addresses only when necessary.
  590          */
  591         in6_clearscope(&ip6->ip6_src);
  592         in6_clearscope(&ip6->ip6_dst);
  593 
  594         /* Jump over all PFIL processing if hooks are not active. */
  595         if (!PFIL_HOOKED(&inet6_pfil_hook))
  596                 goto pass;
  597 
  598         /* Run through list of hooks for output packets. */
  599         error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL);
  600         if (error != 0)
  601                 goto senderr;
  602         if (m == NULL)
  603                 goto freecopy;
  604         ip6 = mtod(m, struct ip6_hdr *);
  605 
  606 pass:
  607         error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
  608         if (error) {
  609                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
  610                 ip6stat.ip6s_cantforward++;
  611         } else {
  612                 ip6stat.ip6s_forward++;
  613                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
  614                 if (type)
  615                         ip6stat.ip6s_redirectsent++;
  616                 else {
  617                         if (mcopy)
  618                                 goto freecopy;
  619                 }
  620         }
  621 
  622 senderr:
  623         if (mcopy == NULL)
  624                 return;
  625         switch (error) {
  626         case 0:
  627                 if (type == ND_REDIRECT) {
  628                         icmp6_redirect_output(mcopy, rt);
  629                         return;
  630                 }
  631                 goto freecopy;
  632 
  633         case EMSGSIZE:
  634                 /* xxx MTU is constant in PPP? */
  635                 goto freecopy;
  636 
  637         case ENOBUFS:
  638                 /* Tell source to slow down like source quench in IP? */
  639                 goto freecopy;
  640 
  641         case ENETUNREACH:       /* shouldn't happen, checked above */
  642         case EHOSTUNREACH:
  643         case ENETDOWN:
  644         case EHOSTDOWN:
  645         default:
  646                 type = ICMP6_DST_UNREACH;
  647                 code = ICMP6_DST_UNREACH_ADDR;
  648                 break;
  649         }
  650         icmp6_error(mcopy, type, code, 0);
  651         return;
  652 
  653  freecopy:
  654         m_freem(mcopy);
  655         return;
  656 }

Cache object: 73767d656dfee5e8a673c7ffb280cfe7


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.