1 /* $NetBSD: ip6_forward.c,v 1.62 2008/01/14 04:16:45 dyoung Exp $ */ 2 /* $KAME: ip6_forward.c,v 1.109 2002/09/11 08:10:17 sakane Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: ip6_forward.c,v 1.62 2008/01/14 04:16:45 dyoung Exp $"); 35 36 #include "opt_ipsec.h" 37 #include "opt_pfil_hooks.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/malloc.h> 42 #include <sys/mbuf.h> 43 #include <sys/domain.h> 44 #include <sys/protosw.h> 45 #include <sys/socket.h> 46 #include <sys/errno.h> 47 #include <sys/time.h> 48 #include <sys/kernel.h> 49 #include <sys/syslog.h> 50 51 #include <net/if.h> 52 #include <net/route.h> 53 54 #include <netinet/in.h> 55 #include <netinet/in_var.h> 56 #include <netinet/ip_var.h> 57 #include <netinet/ip6.h> 58 #include <netinet6/ip6_var.h> 59 #include <netinet6/scope6_var.h> 60 #include <netinet/icmp6.h> 61 #include <netinet6/nd6.h> 62 63 #ifdef IPSEC 64 #include <netinet6/ipsec.h> 65 #include <netkey/key.h> 66 #endif /* IPSEC */ 67 68 #ifdef FAST_IPSEC 69 #include <netipsec/ipsec.h> 70 #include <netipsec/ipsec6.h> 71 #include <netipsec/key.h> 72 #include <netipsec/xform.h> 73 #endif /* FAST_IPSEC */ 74 75 #ifdef PFIL_HOOKS 76 #include <net/pfil.h> 77 #endif 78 79 #include <net/net_osdep.h> 80 81 struct route ip6_forward_rt; 82 83 #ifdef PFIL_HOOKS 84 extern struct pfil_head inet6_pfil_hook; /* XXX */ 85 #endif 86 87 /* 88 * Forward a packet. If some error occurs return the sender 89 * an icmp packet. Note we can't always generate a meaningful 90 * icmp message because icmp doesn't have a large enough repertoire 91 * of codes and types. 92 * 93 * If not forwarding, just drop the packet. This could be confusing 94 * if ipforwarding was zero but some routing protocol was advancing 95 * us as a gateway to somewhere. However, we must let the routing 96 * protocol deal with that. 97 * 98 */ 99 100 void 101 ip6_forward(struct mbuf *m, int srcrt) 102 { 103 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 104 const struct sockaddr_in6 *dst; 105 struct rtentry *rt; 106 int error = 0, type = 0, code = 0; 107 struct mbuf *mcopy = NULL; 108 struct ifnet *origifp; /* maybe unnecessary */ 109 u_int32_t inzone, outzone; 110 struct in6_addr src_in6, dst_in6; 111 #ifdef IPSEC 112 struct secpolicy *sp = NULL; 113 int ipsecrt = 0; 114 #endif 115 #ifdef FAST_IPSEC 116 struct secpolicy *sp = NULL; 117 int needipsec = 0; 118 int s; 119 #endif 120 121 122 #ifdef IPSEC 123 /* 124 * Check AH/ESP integrity. 125 */ 126 /* 127 * Don't increment ip6s_cantforward because this is the check 128 * before forwarding packet actually. 129 */ 130 if (ipsec6_in_reject(m, NULL)) { 131 ipsec6stat.in_polvio++; 132 m_freem(m); 133 return; 134 } 135 #endif /* IPSEC */ 136 137 /* 138 * Do not forward packets to multicast destination (should be handled 139 * by ip6_mforward(). 140 * Do not forward packets with unspecified source. It was discussed 141 * in July 2000, on ipngwg mailing list. 142 */ 143 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 144 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 145 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 146 ip6stat.ip6s_cantforward++; 147 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 148 if (ip6_log_time + ip6_log_interval < time_second) { 149 ip6_log_time = time_second; 150 log(LOG_DEBUG, 151 "cannot forward " 152 "from %s to %s nxt %d received on %s\n", 153 ip6_sprintf(&ip6->ip6_src), 154 ip6_sprintf(&ip6->ip6_dst), 155 ip6->ip6_nxt, 156 if_name(m->m_pkthdr.rcvif)); 157 } 158 m_freem(m); 159 return; 160 } 161 162 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 163 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 164 icmp6_error(m, ICMP6_TIME_EXCEEDED, 165 ICMP6_TIME_EXCEED_TRANSIT, 0); 166 return; 167 } 168 ip6->ip6_hlim -= IPV6_HLIMDEC; 169 170 /* 171 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 172 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 173 * we need to generate an ICMP6 message to the src. 174 * Thanks to M_EXT, in most cases copy will not occur. 175 * 176 * It is important to save it before IPsec processing as IPsec 177 * processing may modify the mbuf. 178 */ 179 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 180 181 #ifdef IPSEC 182 /* get a security policy for this packet */ 183 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 184 IP_FORWARDING, &error); 185 if (sp == NULL) { 186 ipsec6stat.out_inval++; 187 ip6stat.ip6s_cantforward++; 188 if (mcopy) { 189 #if 0 190 /* XXX: what icmp ? */ 191 #else 192 m_freem(mcopy); 193 #endif 194 } 195 m_freem(m); 196 return; 197 } 198 199 error = 0; 200 201 /* check policy */ 202 switch (sp->policy) { 203 case IPSEC_POLICY_DISCARD: 204 /* 205 * This packet is just discarded. 206 */ 207 ipsec6stat.out_polvio++; 208 ip6stat.ip6s_cantforward++; 209 key_freesp(sp); 210 if (mcopy) { 211 #if 0 212 /* XXX: what icmp ? */ 213 #else 214 m_freem(mcopy); 215 #endif 216 } 217 m_freem(m); 218 return; 219 220 case IPSEC_POLICY_BYPASS: 221 case IPSEC_POLICY_NONE: 222 /* no need to do IPsec. */ 223 key_freesp(sp); 224 goto skip_ipsec; 225 226 case IPSEC_POLICY_IPSEC: 227 if (sp->req == NULL) { 228 /* XXX should be panic ? */ 229 printf("ip6_forward: No IPsec request specified.\n"); 230 ip6stat.ip6s_cantforward++; 231 key_freesp(sp); 232 if (mcopy) { 233 #if 0 234 /* XXX: what icmp ? */ 235 #else 236 m_freem(mcopy); 237 #endif 238 } 239 m_freem(m); 240 return; 241 } 242 /* do IPsec */ 243 break; 244 245 case IPSEC_POLICY_ENTRUST: 246 default: 247 /* should be panic ?? */ 248 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 249 key_freesp(sp); 250 goto skip_ipsec; 251 } 252 253 { 254 struct ipsecrequest *isr = NULL; 255 struct ipsec_output_state state; 256 257 /* 258 * when the kernel forwards a packet, it is not proper to apply 259 * IPsec transport mode to the packet is not proper. this check 260 * avoid from this. 261 * at present, if there is even a transport mode SA request in the 262 * security policy, the kernel does not apply IPsec to the packet. 263 * this check is not enough because the following case is valid. 264 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require; 265 */ 266 for (isr = sp->req; isr; isr = isr->next) { 267 if (isr->saidx.mode == IPSEC_MODE_ANY) 268 goto doipsectunnel; 269 if (isr->saidx.mode == IPSEC_MODE_TUNNEL) 270 goto doipsectunnel; 271 } 272 273 /* 274 * if there's no need for tunnel mode IPsec, skip. 275 */ 276 if (!isr) 277 goto skip_ipsec; 278 279 doipsectunnel: 280 /* 281 * All the extension headers will become inaccessible 282 * (since they can be encrypted). 283 * Don't panic, we need no more updates to extension headers 284 * on inner IPv6 packet (since they are now encapsulated). 285 * 286 * IPv6 [ESP|AH] IPv6 [extension headers] payload 287 */ 288 bzero(&state, sizeof(state)); 289 state.m = m; 290 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 291 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 292 293 error = ipsec6_output_tunnel(&state, sp, 0); 294 295 m = state.m; 296 key_freesp(sp); 297 298 if (error) { 299 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 300 switch (error) { 301 case EHOSTUNREACH: 302 case ENETUNREACH: 303 case EMSGSIZE: 304 case ENOBUFS: 305 case ENOMEM: 306 break; 307 default: 308 printf("ip6_forward (ipsec): error code %d\n", error); 309 /* FALLTHROUGH */ 310 case ENOENT: 311 /* don't show these error codes to the user */ 312 break; 313 } 314 ip6stat.ip6s_cantforward++; 315 if (mcopy) { 316 #if 0 317 /* XXX: what icmp ? */ 318 #else 319 m_freem(mcopy); 320 #endif 321 } 322 m_freem(m); 323 return; 324 } 325 326 if (ip6 != mtod(m, struct ip6_hdr *)) { 327 /* 328 * now tunnel mode headers are added. we are originating 329 * packet instead of forwarding the packet. 330 */ 331 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL, 332 NULL); 333 goto freecopy; 334 } 335 336 /* adjust pointer */ 337 rt = state.ro ? rtcache_validate(state.ro) : NULL; 338 dst = (const struct sockaddr_in6 *)state.dst; 339 if (dst != NULL && rt != NULL) { 340 ipsecrt = 1; 341 goto skip_routing; 342 } 343 } 344 skip_ipsec: 345 #endif /* IPSEC */ 346 #ifdef FAST_IPSEC 347 /* Check the security policy (SP) for the packet */ 348 349 sp = ipsec6_check_policy(m,NULL,0,&needipsec,&error); 350 if (error != 0) { 351 /* 352 * Hack: -EINVAL is used to signal that a packet 353 * should be silently discarded. This is typically 354 * because we asked key management for an SA and 355 * it was delayed (e.g. kicked up to IKE). 356 */ 357 if (error == -EINVAL) 358 error = 0; 359 goto freecopy; 360 } 361 #endif /* FAST_IPSEC */ 362 363 if (srcrt) { 364 union { 365 struct sockaddr dst; 366 struct sockaddr_in6 dst6; 367 } u; 368 369 sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0); 370 if ((rt = rtcache_lookup(&ip6_forward_rt, &u.dst)) == NULL) { 371 ip6stat.ip6s_noroute++; 372 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 373 if (mcopy) { 374 icmp6_error(mcopy, ICMP6_DST_UNREACH, 375 ICMP6_DST_UNREACH_NOROUTE, 0); 376 } 377 m_freem(m); 378 return; 379 } 380 } else if ((rt = rtcache_validate(&ip6_forward_rt)) == NULL && 381 (rt = rtcache_update(&ip6_forward_rt, 1)) == NULL) { 382 /* 383 * rtcache_getdst(ip6_forward_rt)->sin6_addr was equal to 384 * ip6->ip6_dst 385 */ 386 ip6stat.ip6s_noroute++; 387 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 388 if (mcopy) { 389 icmp6_error(mcopy, ICMP6_DST_UNREACH, 390 ICMP6_DST_UNREACH_NOROUTE, 0); 391 } 392 m_freem(m); 393 return; 394 } 395 dst = satocsin6(rtcache_getdst(&ip6_forward_rt)); 396 #ifdef IPSEC 397 skip_routing:; 398 #endif /* IPSEC */ 399 400 /* 401 * Source scope check: if a packet can't be delivered to its 402 * destination for the reason that the destination is beyond the scope 403 * of the source address, discard the packet and return an icmp6 404 * destination unreachable error with Code 2 (beyond scope of source 405 * address). We use a local copy of ip6_src, since in6_setscope() 406 * will possibly modify its first argument. 407 * [draft-ietf-ipngwg-icmp-v3-07, Section 3.1] 408 */ 409 src_in6 = ip6->ip6_src; 410 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 411 /* XXX: this should not happen */ 412 ip6stat.ip6s_cantforward++; 413 ip6stat.ip6s_badscope++; 414 m_freem(m); 415 return; 416 } 417 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 418 ip6stat.ip6s_cantforward++; 419 ip6stat.ip6s_badscope++; 420 m_freem(m); 421 return; 422 } 423 if (inzone != outzone 424 #ifdef IPSEC 425 && !ipsecrt 426 #endif 427 ) { 428 ip6stat.ip6s_cantforward++; 429 ip6stat.ip6s_badscope++; 430 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 431 432 if (ip6_log_time + ip6_log_interval < time_second) { 433 ip6_log_time = time_second; 434 log(LOG_DEBUG, 435 "cannot forward " 436 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 437 ip6_sprintf(&ip6->ip6_src), 438 ip6_sprintf(&ip6->ip6_dst), 439 ip6->ip6_nxt, 440 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 441 } 442 if (mcopy) 443 icmp6_error(mcopy, ICMP6_DST_UNREACH, 444 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 445 m_freem(m); 446 return; 447 } 448 #ifdef FAST_IPSEC 449 /* 450 * If we need to encapsulate the packet, do it here 451 * ipsec6_proces_packet will send the packet using ip6_output 452 */ 453 if (needipsec) { 454 s = splsoftnet(); 455 error = ipsec6_process_packet(m,sp->req); 456 splx(s); 457 if (mcopy) 458 goto freecopy; 459 } 460 #endif 461 462 463 464 /* 465 * Destination scope check: if a packet is going to break the scope 466 * zone of packet's destination address, discard it. This case should 467 * usually be prevented by appropriately-configured routing table, but 468 * we need an explicit check because we may mistakenly forward the 469 * packet to a different zone by (e.g.) a default route. 470 */ 471 dst_in6 = ip6->ip6_dst; 472 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 473 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 474 inzone != outzone) { 475 ip6stat.ip6s_cantforward++; 476 ip6stat.ip6s_badscope++; 477 m_freem(m); 478 return; 479 } 480 481 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) { 482 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 483 if (mcopy) { 484 u_long mtu; 485 #ifdef IPSEC 486 struct secpolicy *xsp; 487 int ipsecerror; 488 size_t ipsechdrsiz; 489 #endif 490 491 mtu = IN6_LINKMTU(rt->rt_ifp); 492 #ifdef IPSEC 493 /* 494 * When we do IPsec tunnel ingress, we need to play 495 * with the link value (decrement IPsec header size 496 * from mtu value). The code is much simpler than v4 497 * case, as we have the outgoing interface for 498 * encapsulated packet as "rt->rt_ifp". 499 */ 500 xsp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 501 IP_FORWARDING, &ipsecerror); 502 if (xsp) { 503 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 504 IPSEC_DIR_OUTBOUND, NULL); 505 if (ipsechdrsiz < mtu) 506 mtu -= ipsechdrsiz; 507 } 508 509 /* 510 * if mtu becomes less than minimum MTU, 511 * tell minimum MTU (and I'll need to fragment it). 512 */ 513 if (mtu < IPV6_MMTU) 514 mtu = IPV6_MMTU; 515 #endif 516 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 517 } 518 m_freem(m); 519 return; 520 } 521 522 if (rt->rt_flags & RTF_GATEWAY) 523 dst = (struct sockaddr_in6 *)rt->rt_gateway; 524 525 /* 526 * If we are to forward the packet using the same interface 527 * as one we got the packet from, perhaps we should send a redirect 528 * to sender to shortcut a hop. 529 * Only send redirect if source is sending directly to us, 530 * and if packet was not source routed (or has any options). 531 * Also, don't send redirect if forwarding using a route 532 * modified by a redirect. 533 */ 534 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && ip6_sendredirects && 535 #ifdef IPSEC 536 !ipsecrt && 537 #endif 538 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 539 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) && 540 nd6_is_addr_neighbor( 541 satocsin6(rtcache_getdst(&ip6_forward_rt)), 542 rt->rt_ifp)) { 543 /* 544 * If the incoming interface is equal to the outgoing 545 * one, the link attached to the interface is 546 * point-to-point, and the IPv6 destination is 547 * regarded as on-link on the link, then it will be 548 * highly probable that the destination address does 549 * not exist on the link and that the packet is going 550 * to loop. Thus, we immediately drop the packet and 551 * send an ICMPv6 error message. 552 * For other routing loops, we dare to let the packet 553 * go to the loop, so that a remote diagnosing host 554 * can detect the loop by traceroute. 555 * type/code is based on suggestion by Rich Draves. 556 * not sure if it is the best pick. 557 */ 558 icmp6_error(mcopy, ICMP6_DST_UNREACH, 559 ICMP6_DST_UNREACH_ADDR, 0); 560 m_freem(m); 561 return; 562 } 563 type = ND_REDIRECT; 564 } 565 566 /* 567 * Fake scoped addresses. Note that even link-local source or 568 * destinaion can appear, if the originating node just sends the 569 * packet to us (without address resolution for the destination). 570 * Since both icmp6_error and icmp6_redirect_output fill the embedded 571 * link identifiers, we can do this stuff after making a copy for 572 * returning an error. 573 */ 574 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 575 /* 576 * See corresponding comments in ip6_output. 577 * XXX: but is it possible that ip6_forward() sends a packet 578 * to a loopback interface? I don't think so, and thus 579 * I bark here. (jinmei@kame.net) 580 * XXX: it is common to route invalid packets to loopback. 581 * also, the codepath will be visited on use of ::1 in 582 * rthdr. (itojun) 583 */ 584 #if 1 585 if (0) 586 #else 587 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 588 #endif 589 { 590 printf("ip6_forward: outgoing interface is loopback. " 591 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 592 ip6_sprintf(&ip6->ip6_src), 593 ip6_sprintf(&ip6->ip6_dst), 594 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 595 if_name(rt->rt_ifp)); 596 } 597 598 /* we can just use rcvif in forwarding. */ 599 origifp = m->m_pkthdr.rcvif; 600 } 601 else 602 origifp = rt->rt_ifp; 603 /* 604 * clear embedded scope identifiers if necessary. 605 * in6_clearscope will touch the addresses only when necessary. 606 */ 607 in6_clearscope(&ip6->ip6_src); 608 in6_clearscope(&ip6->ip6_dst); 609 610 #ifdef PFIL_HOOKS 611 /* 612 * Run through list of hooks for output packets. 613 */ 614 if ((error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, 615 PFIL_OUT)) != 0) 616 goto senderr; 617 if (m == NULL) 618 goto freecopy; 619 ip6 = mtod(m, struct ip6_hdr *); 620 #endif /* PFIL_HOOKS */ 621 622 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 623 if (error) { 624 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 625 ip6stat.ip6s_cantforward++; 626 } else { 627 ip6stat.ip6s_forward++; 628 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 629 if (type) 630 ip6stat.ip6s_redirectsent++; 631 else { 632 #ifdef GATEWAY 633 if (m->m_flags & M_CANFASTFWD) 634 ip6flow_create(&ip6_forward_rt, m); 635 #endif 636 if (mcopy) 637 goto freecopy; 638 } 639 } 640 641 #ifdef PFIL_HOOKS 642 senderr: 643 #endif 644 if (mcopy == NULL) 645 return; 646 switch (error) { 647 case 0: 648 if (type == ND_REDIRECT) { 649 icmp6_redirect_output(mcopy, rt); 650 return; 651 } 652 goto freecopy; 653 654 case EMSGSIZE: 655 /* xxx MTU is constant in PPP? */ 656 goto freecopy; 657 658 case ENOBUFS: 659 /* Tell source to slow down like source quench in IP? */ 660 goto freecopy; 661 662 case ENETUNREACH: /* shouldn't happen, checked above */ 663 case EHOSTUNREACH: 664 case ENETDOWN: 665 case EHOSTDOWN: 666 default: 667 type = ICMP6_DST_UNREACH; 668 code = ICMP6_DST_UNREACH_ADDR; 669 break; 670 } 671 icmp6_error(mcopy, type, code, 0); 672 return; 673 674 freecopy: 675 m_freem(mcopy); 676 return; 677 } 678