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 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 V_ipsec6stat.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_second) { 141 V_ip6_log_time = time_second; 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 V_ipsec6stat.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 V_ipsec6stat.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_second) { 409 V_ip6_log_time = time_second; 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) 567 goto senderr; 568 if (m == NULL) 569 goto freecopy; 570 ip6 = mtod(m, struct ip6_hdr *); 571 572 /* See if destination IP address was changed by packet filter. */ 573 if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) { 574 m->m_flags |= M_SKIP_FIREWALL; 575 /* If destination is now ourself drop to ip6_input(). */ 576 if (in6_localip(&ip6->ip6_dst)) { 577 m->m_flags |= M_FASTFWD_OURS; 578 if (m->m_pkthdr.rcvif == NULL) 579 m->m_pkthdr.rcvif = V_loif; 580 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 581 m->m_pkthdr.csum_flags |= 582 CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR; 583 m->m_pkthdr.csum_data = 0xffff; 584 } 585 #ifdef SCTP 586 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) 587 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 588 #endif 589 error = netisr_queue(NETISR_IPV6, m); 590 goto out; 591 } else 592 goto again; /* Redo the routing table lookup. */ 593 } 594 595 /* See if local, if yes, send it to netisr. */ 596 if (m->m_flags & M_FASTFWD_OURS) { 597 if (m->m_pkthdr.rcvif == NULL) 598 m->m_pkthdr.rcvif = V_loif; 599 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { 600 m->m_pkthdr.csum_flags |= 601 CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR; 602 m->m_pkthdr.csum_data = 0xffff; 603 } 604 #ifdef SCTP 605 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) 606 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 607 #endif 608 error = netisr_queue(NETISR_IPV6, m); 609 goto out; 610 } 611 /* Or forward to some other address? */ 612 if ((m->m_flags & M_IP6_NEXTHOP) && 613 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) { 614 dst = (struct sockaddr_in6 *)&rin6.ro_dst; 615 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in6)); 616 m->m_flags |= M_SKIP_FIREWALL; 617 m->m_flags &= ~M_IP6_NEXTHOP; 618 m_tag_delete(m, fwd_tag); 619 goto again2; 620 } 621 622 pass: 623 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 624 if (error) { 625 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 626 IP6STAT_INC(ip6s_cantforward); 627 } else { 628 IP6STAT_INC(ip6s_forward); 629 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 630 if (type) 631 IP6STAT_INC(ip6s_redirectsent); 632 else { 633 if (mcopy) 634 goto freecopy; 635 } 636 } 637 638 senderr: 639 if (mcopy == NULL) 640 goto out; 641 switch (error) { 642 case 0: 643 if (type == ND_REDIRECT) { 644 icmp6_redirect_output(mcopy, rt); 645 goto out; 646 } 647 goto freecopy; 648 649 case EMSGSIZE: 650 /* xxx MTU is constant in PPP? */ 651 goto freecopy; 652 653 case ENOBUFS: 654 /* Tell source to slow down like source quench in IP? */ 655 goto freecopy; 656 657 case ENETUNREACH: /* shouldn't happen, checked above */ 658 case EHOSTUNREACH: 659 case ENETDOWN: 660 case EHOSTDOWN: 661 default: 662 type = ICMP6_DST_UNREACH; 663 code = ICMP6_DST_UNREACH_ADDR; 664 break; 665 } 666 icmp6_error(mcopy, type, code, 0); 667 goto out; 668 669 freecopy: 670 m_freem(mcopy); 671 goto out; 672 bad: 673 m_freem(m); 674 out: 675 if (rt != NULL 676 #ifdef IPSEC 677 && !ipsecrt 678 #endif 679 ) 680 RTFREE(rt); 681 } 682