sys/netinet6/ip6_forward.c

   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_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 #ifdef IPFIREWALL_FORWARD
 112         struct m_tag *fwd_tag;
 113 #endif
 114         char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
 115
 116 #ifdef IPSEC
 117         /*
 118          * Check AH/ESP integrity.
 119          */
 120         /*
 121          * Don't increment ip6s_cantforward because this is the check
 122          * before forwarding packet actually.
 123          */
 124         if (ipsec6_in_reject(m, NULL)) {
 125                 V_ipsec6stat.in_polvio++;
 126                 m_freem(m);
 127                 return;
 128         }
 129 #endif /* IPSEC */
 130
 131         /*
 132          * Do not forward packets to multicast destination (should be handled
 133          * by ip6_mforward().
 134          * Do not forward packets with unspecified source.  It was discussed
 135          * in July 2000, on the ipngwg mailing list.
 136          */
 137         if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
 138             IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
 139             IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
 140                 V_ip6stat.ip6s_cantforward++;
 141                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
 142                 if (V_ip6_log_time + V_ip6_log_interval < time_second) {
 143                         V_ip6_log_time = time_second;
 144                         log(LOG_DEBUG,
 145                             "cannot forward "
 146                             "from %s to %s nxt %d received on %s\n",
 147                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
 148                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 149                             ip6->ip6_nxt,
 150                             if_name(m->m_pkthdr.rcvif));
 151                 }
 152                 m_freem(m);
 153                 return;
 154         }
 155
 156 #ifdef IPSTEALTH
 157         if (!V_ip6stealth) {
 158 #endif
 159         if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
 160                 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
 161                 icmp6_error(m, ICMP6_TIME_EXCEEDED,
 162                                 ICMP6_TIME_EXCEED_TRANSIT, 0);
 163                 return;
 164         }
 165         ip6->ip6_hlim -= IPV6_HLIMDEC;
 166
 167 #ifdef IPSTEALTH
 168         }
 169 #endif
 170
 171         /*
 172          * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
 173          * size of IPv6 + ICMPv6 headers) bytes of the packet in case
 174          * we need to generate an ICMP6 message to the src.
 175          * Thanks to M_EXT, in most cases copy will not occur.
 176          *
 177          * It is important to save it before IPsec processing as IPsec
 178          * processing may modify the mbuf.
 179          */
 180         mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
 181
 182 #ifdef IPSEC
 183         /* get a security policy for this packet */
 184         sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
 185             IP_FORWARDING, &error);
 186         if (sp == NULL) {
 187                 V_ipsec6stat.out_inval++;
 188                 V_ip6stat.ip6s_cantforward++;
 189                 if (mcopy) {
 190 #if 0
 191                         /* XXX: what icmp ? */
 192 #else
 193                         m_freem(mcopy);
 194 #endif
 195                 }
 196                 m_freem(m);
 197                 return;
 198         }
 199
 200         error = 0;
 201
 202         /* check policy */
 203         switch (sp->policy) {
 204         case IPSEC_POLICY_DISCARD:
 205                 /*
 206                  * This packet is just discarded.
 207                  */
 208                 V_ipsec6stat.out_polvio++;
 209                 V_ip6stat.ip6s_cantforward++;
 210                 KEY_FREESP(&sp);
 211                 if (mcopy) {
 212 #if 0
 213                         /* XXX: what icmp ? */
 214 #else
 215                         m_freem(mcopy);
 216 #endif
 217                 }
 218                 m_freem(m);
 219                 return;
 220
 221         case IPSEC_POLICY_BYPASS:
 222         case IPSEC_POLICY_NONE:
 223                 /* no need to do IPsec. */
 224                 KEY_FREESP(&sp);
 225                 goto skip_ipsec;
 226
 227         case IPSEC_POLICY_IPSEC:
 228                 if (sp->req == NULL) {
 229                         /* XXX should be panic ? */
 230                         printf("ip6_forward: No IPsec request specified.\n");
 231                         V_ip6stat.ip6s_cantforward++;
 232                         KEY_FREESP(&sp);
 233                         if (mcopy) {
 234 #if 0
 235                                 /* XXX: what icmp ? */
 236 #else
 237                                 m_freem(mcopy);
 238 #endif
 239                         }
 240                         m_freem(m);
 241                         return;
 242                 }
 243                 /* do IPsec */
 244                 break;
 245
 246         case IPSEC_POLICY_ENTRUST:
 247         default:
 248                 /* should be panic ?? */
 249                 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
 250                 KEY_FREESP(&sp);
 251                 goto skip_ipsec;
 252         }
 253
 254     {
 255         struct ipsecrequest *isr = NULL;
 256         struct ipsec_output_state state;
 257
 258         /*
 259          * when the kernel forwards a packet, it is not proper to apply
 260          * IPsec transport mode to the packet is not proper.  this check
 261          * avoid from this.
 262          * at present, if there is even a transport mode SA request in the
 263          * security policy, the kernel does not apply IPsec to the packet.
 264          * this check is not enough because the following case is valid.
 265          *      ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
 266          */
 267         for (isr = sp->req; isr; isr = isr->next) {
 268                 if (isr->saidx.mode == IPSEC_MODE_ANY)
 269                         goto doipsectunnel;
 270                 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
 271                         goto doipsectunnel;
 272         }
 273
 274         /*
 275          * if there's no need for tunnel mode IPsec, skip.
 276          */
 277         if (!isr)
 278                 goto skip_ipsec;
 279
 280     doipsectunnel:
 281         /*
 282          * All the extension headers will become inaccessible
 283          * (since they can be encrypted).
 284          * Don't panic, we need no more updates to extension headers
 285          * on inner IPv6 packet (since they are now encapsulated).
 286          *
 287          * IPv6 [ESP|AH] IPv6 [extension headers] payload
 288          */
 289         bzero(&state, sizeof(state));
 290         state.m = m;
 291         state.ro = NULL;        /* update at ipsec6_output_tunnel() */
 292         state.dst = NULL;       /* update at ipsec6_output_tunnel() */
 293
 294         error = ipsec6_output_tunnel(&state, sp, 0);
 295
 296         m = state.m;
 297         KEY_FREESP(&sp);
 298
 299         if (error) {
 300                 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
 301                 switch (error) {
 302                 case EHOSTUNREACH:
 303                 case ENETUNREACH:
 304                 case EMSGSIZE:
 305                 case ENOBUFS:
 306                 case ENOMEM:
 307                         break;
 308                 default:
 309                         printf("ip6_output (ipsec): error code %d\n", error);
 310                         /* FALLTHROUGH */
 311                 case ENOENT:
 312                         /* don't show these error codes to the user */
 313                         break;
 314                 }
 315                 V_ip6stat.ip6s_cantforward++;
 316                 if (mcopy) {
 317 #if 0
 318                         /* XXX: what icmp ? */
 319 #else
 320                         m_freem(mcopy);
 321 #endif
 322                 }
 323                 m_freem(m);
 324                 return;
 325         } else {
 326                 /*
 327                  * In the FAST IPSec case we have already
 328                  * re-injected the packet and it has been freed
 329                  * by the ipsec_done() function.  So, just clean
 330                  * up after ourselves.
 331                  */
 332                 m = NULL;
 333                 goto freecopy;
 334         }
 335
 336         if ((m != NULL) && (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         if (ipsecrt)
 353                 goto skip_routing;
 354 skip_ipsec:
 355 #endif
 356 again:
 357         bzero(&rin6, sizeof(struct route_in6));
 358         dst = (struct sockaddr_in6 *)&rin6.ro_dst;
 359         dst->sin6_len = sizeof(struct sockaddr_in6);
 360         dst->sin6_family = AF_INET6;
 361         dst->sin6_addr = ip6->ip6_dst;
 362 #ifdef IPFIREWALL_FORWARD
 363 again2:
 364 #endif
 365         rin6.ro_rt = rtalloc1((struct sockaddr *)dst, 0, 0);
 366         if (rin6.ro_rt != NULL)
 367                 RT_UNLOCK(rin6.ro_rt);
 368         else {
 369                 V_ip6stat.ip6s_noroute++;
 370                 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
 371                 if (mcopy) {
 372                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
 373                         ICMP6_DST_UNREACH_NOROUTE, 0);
 374                 }
 375                 goto bad;
 376         }
 377         rt = rin6.ro_rt;
 378 #ifdef IPSEC
 379 skip_routing:
 380 #endif
 381
 382         /*
 383          * Source scope check: if a packet can't be delivered to its
 384          * destination for the reason that the destination is beyond the scope
 385          * of the source address, discard the packet and return an icmp6
 386          * destination unreachable error with Code 2 (beyond scope of source
 387          * address).  We use a local copy of ip6_src, since in6_setscope()
 388          * will possibly modify its first argument.
 389          * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
 390          */
 391         src_in6 = ip6->ip6_src;
 392         if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
 393                 /* XXX: this should not happen */
 394                 V_ip6stat.ip6s_cantforward++;
 395                 V_ip6stat.ip6s_badscope++;
 396                 goto bad;
 397         }
 398         if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
 399                 V_ip6stat.ip6s_cantforward++;
 400                 V_ip6stat.ip6s_badscope++;
 401                 goto bad;
 402         }
 403         if (inzone != outzone
 404 #ifdef IPSEC
 405             && !ipsecrt
 406 #endif
 407             ) {
 408                 V_ip6stat.ip6s_cantforward++;
 409                 V_ip6stat.ip6s_badscope++;
 410                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
 411
 412                 if (V_ip6_log_time + V_ip6_log_interval < time_second) {
 413                         V_ip6_log_time = time_second;
 414                         log(LOG_DEBUG,
 415                             "cannot forward "
 416                             "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
 417                             ip6_sprintf(ip6bufs, &ip6->ip6_src),
 418                             ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 419                             ip6->ip6_nxt,
 420                             if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
 421                 }
 422                 if (mcopy)
 423                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
 424                                     ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
 425                 goto bad;
 426         }
 427
 428         /*
 429          * Destination scope check: if a packet is going to break the scope
 430          * zone of packet's destination address, discard it.  This case should
 431          * usually be prevented by appropriately-configured routing table, but
 432          * we need an explicit check because we may mistakenly forward the
 433          * packet to a different zone by (e.g.) a default route.
 434          */
 435         dst_in6 = ip6->ip6_dst;
 436         if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
 437             in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
 438             inzone != outzone) {
 439                 V_ip6stat.ip6s_cantforward++;
 440                 V_ip6stat.ip6s_badscope++;
 441                 goto bad;
 442         }
 443
 444         if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
 445                 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
 446                 if (mcopy) {
 447                         u_long mtu;
 448 #ifdef IPSEC
 449                         struct secpolicy *sp;
 450                         int ipsecerror;
 451                         size_t ipsechdrsiz;
 452 #endif /* IPSEC */
 453
 454                         mtu = IN6_LINKMTU(rt->rt_ifp);
 455 #ifdef IPSEC
 456                         /*
 457                          * When we do IPsec tunnel ingress, we need to play
 458                          * with the link value (decrement IPsec header size
 459                          * from mtu value).  The code is much simpler than v4
 460                          * case, as we have the outgoing interface for
 461                          * encapsulated packet as "rt->rt_ifp".
 462                          */
 463                         sp = ipsec_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
 464                                 IP_FORWARDING, &ipsecerror);
 465                         if (sp) {
 466                                 ipsechdrsiz = ipsec_hdrsiz(mcopy,
 467                                         IPSEC_DIR_OUTBOUND, NULL);
 468                                 if (ipsechdrsiz < mtu)
 469                                         mtu -= ipsechdrsiz;
 470                         }
 471
 472                         /*
 473                          * if mtu becomes less than minimum MTU,
 474                          * tell minimum MTU (and I'll need to fragment it).
 475                          */
 476                         if (mtu < IPV6_MMTU)
 477                                 mtu = IPV6_MMTU;
 478 #endif /* IPSEC */
 479                         icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
 480                 }
 481                 goto bad;
 482         }
 483
 484         if (rt->rt_flags & RTF_GATEWAY)
 485                 dst = (struct sockaddr_in6 *)rt->rt_gateway;
 486
 487         /*
 488          * If we are to forward the packet using the same interface
 489          * as one we got the packet from, perhaps we should send a redirect
 490          * to sender to shortcut a hop.
 491          * Only send redirect if source is sending directly to us,
 492          * and if packet was not source routed (or has any options).
 493          * Also, don't send redirect if forwarding using a route
 494          * modified by a redirect.
 495          */
 496         if (V_ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
 497 #ifdef IPSEC
 498             !ipsecrt &&
 499 #endif /* IPSEC */
 500             (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
 501                 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
 502                         /*
 503                          * If the incoming interface is equal to the outgoing
 504                          * one, and the link attached to the interface is
 505                          * point-to-point, then it will be highly probable
 506                          * that a routing loop occurs. Thus, we immediately
 507                          * drop the packet and send an ICMPv6 error message.
 508                          *
 509                          * type/code is based on suggestion by Rich Draves.
 510                          * not sure if it is the best pick.
 511                          */
 512                         icmp6_error(mcopy, ICMP6_DST_UNREACH,
 513                                     ICMP6_DST_UNREACH_ADDR, 0);
 514                         goto bad;
 515                 }
 516                 type = ND_REDIRECT;
 517         }
 518
 519         /*
 520          * Fake scoped addresses. Note that even link-local source or
 521          * destinaion can appear, if the originating node just sends the
 522          * packet to us (without address resolution for the destination).
 523          * Since both icmp6_error and icmp6_redirect_output fill the embedded
 524          * link identifiers, we can do this stuff after making a copy for
 525          * returning an error.
 526          */
 527         if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
 528                 /*
 529                  * See corresponding comments in ip6_output.
 530                  * XXX: but is it possible that ip6_forward() sends a packet
 531                  *      to a loopback interface? I don't think so, and thus
 532                  *      I bark here. (jinmei@kame.net)
 533                  * XXX: it is common to route invalid packets to loopback.
 534                  *      also, the codepath will be visited on use of ::1 in
 535                  *      rthdr. (itojun)
 536                  */
 537 #if 1
 538                 if (0)
 539 #else
 540                 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
 541 #endif
 542                 {
 543                         printf("ip6_forward: outgoing interface is loopback. "
 544                                "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
 545                                ip6_sprintf(ip6bufs, &ip6->ip6_src),
 546                                ip6_sprintf(ip6bufd, &ip6->ip6_dst),
 547                                ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
 548                                if_name(rt->rt_ifp));
 549                 }
 550
 551                 /* we can just use rcvif in forwarding. */
 552                 origifp = m->m_pkthdr.rcvif;
 553         }
 554         else
 555                 origifp = rt->rt_ifp;
 556         /*
 557          * clear embedded scope identifiers if necessary.
 558          * in6_clearscope will touch the addresses only when necessary.
 559          */
 560         in6_clearscope(&ip6->ip6_src);
 561         in6_clearscope(&ip6->ip6_dst);
 562
 563         /* Jump over all PFIL processing if hooks are not active. */
 564         if (!PFIL_HOOKED(&V_inet6_pfil_hook))
 565                 goto pass;
 566
 567         odst = ip6->ip6_dst;
 568         /* Run through list of hooks for output packets. */
 569         error = pfil_run_hooks(&V_inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL);
 570         if (error != 0)
 571                 goto senderr;
 572         if (m == NULL)
 573                 goto freecopy;
 574         ip6 = mtod(m, struct ip6_hdr *);
 575
 576         /* See if destination IP address was changed by packet filter. */
 577         if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
 578                 m->m_flags |= M_SKIP_FIREWALL;
 579                 /* If destination is now ourself drop to ip6_input(). */
 580                 if (in6_localip(&ip6->ip6_dst)) {
 581                         m->m_flags |= M_FASTFWD_OURS;
 582                         if (m->m_pkthdr.rcvif == NULL)
 583                                 m->m_pkthdr.rcvif = V_loif;
 584                         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 585                                 m->m_pkthdr.csum_flags |=
 586                                     CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 587                                 m->m_pkthdr.csum_data = 0xffff;
 588                         }
 589                         m->m_pkthdr.csum_flags |=
 590                             CSUM_IP_CHECKED | CSUM_IP_VALID;
 591 #ifdef SCTP
 592                         if (m->m_pkthdr.csum_flags & CSUM_SCTP)
 593                                 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
 594 #endif
 595                         error = netisr_queue(NETISR_IPV6, m);
 596                         goto out;
 597                 } else
 598                         goto again;     /* Redo the routing table lookup. */
 599         }
 600
 601 #ifdef IPFIREWALL_FORWARD
 602         /* See if local, if yes, send it to netisr. */
 603         if (m->m_flags & M_FASTFWD_OURS) {
 604                 if (m->m_pkthdr.rcvif == NULL)
 605                         m->m_pkthdr.rcvif = V_loif;
 606                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
 607                         m->m_pkthdr.csum_flags |=
 608                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
 609                         m->m_pkthdr.csum_data = 0xffff;
 610                 }
 611 #ifdef SCTP
 612                 if (m->m_pkthdr.csum_flags & CSUM_SCTP)
 613                 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
 614 #endif
 615                 error = netisr_queue(NETISR_IPV6, m);
 616                 goto out;
 617         }
 618         /* Or forward to some other address? */
 619         fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
 620         if (fwd_tag) {
 621                 dst = (struct sockaddr_in6 *)&rin6.ro_dst;
 622                 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in6));
 623                 m->m_flags |= M_SKIP_FIREWALL;
 624                 m_tag_delete(m, fwd_tag);
 625                 goto again2;
 626         }
 627 #endif /* IPFIREWALL_FORWARD */
 628
 629 pass:
 630         error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
 631         if (error) {
 632                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
 633                 V_ip6stat.ip6s_cantforward++;
 634         } else {
 635                 V_ip6stat.ip6s_forward++;
 636                 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
 637                 if (type)
 638                         V_ip6stat.ip6s_redirectsent++;
 639                 else {
 640                         if (mcopy)
 641                                 goto freecopy;
 642                 }
 643         }
 644
 645 senderr:
 646         if (mcopy == NULL)
 647                 goto out;
 648         switch (error) {
 649         case 0:
 650                 if (type == ND_REDIRECT) {
 651                         icmp6_redirect_output(mcopy, rt);
 652                         goto out;
 653                 }
 654                 goto freecopy;
 655
 656         case EMSGSIZE:
 657                 /* xxx MTU is constant in PPP? */
 658                 goto freecopy;
 659
 660         case ENOBUFS:
 661                 /* Tell source to slow down like source quench in IP? */
 662                 goto freecopy;
 663
 664         case ENETUNREACH:       /* shouldn't happen, checked above */
 665         case EHOSTUNREACH:
 666         case ENETDOWN:
 667         case EHOSTDOWN:
 668         default:
 669                 type = ICMP6_DST_UNREACH;
 670                 code = ICMP6_DST_UNREACH_ADDR;
 671                 break;
 672         }
 673         icmp6_error(mcopy, type, code, 0);
 674         goto out;
 675
 676  freecopy:
 677         m_freem(mcopy);
 678         goto out;
 679 bad:
 680         m_freem(m);
 681 out:
 682         if (rt != NULL
 683 #ifdef IPSEC
 684             && !ipsecrt
 685 #endif
 686             )
 687                 RTFREE(rt);
 688 }