ip6_forward.c revision 148385
1132332Smarcel/* $FreeBSD: head/sys/netinet6/ip6_forward.c 148385 2005-07-25 12:31:43Z ume $ */ 2132950Sdavidxu/* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */ 3132332Smarcel 4132332Smarcel/*- 5132332Smarcel * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6132332Smarcel * All rights reserved. 7132332Smarcel * 8132332Smarcel * Redistribution and use in source and binary forms, with or without 9132332Smarcel * modification, are permitted provided that the following conditions 10132332Smarcel * are met: 11132332Smarcel * 1. Redistributions of source code must retain the above copyright 12132332Smarcel * notice, this list of conditions and the following disclaimer. 13132332Smarcel * 2. Redistributions in binary form must reproduce the above copyright 14132332Smarcel * notice, this list of conditions and the following disclaimer in the 15132332Smarcel * documentation and/or other materials provided with the distribution. 16132332Smarcel * 3. Neither the name of the project nor the names of its contributors 17132332Smarcel * may be used to endorse or promote products derived from this software 18132332Smarcel * without specific prior written permission. 19132332Smarcel * 20132332Smarcel * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21132332Smarcel * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22132332Smarcel * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23132332Smarcel * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24132332Smarcel * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25132332Smarcel * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26132332Smarcel * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27132332Smarcel * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28132332Smarcel * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29132332Smarcel * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30132332Smarcel * SUCH DAMAGE. 31132360Smarcel */ 32132360Smarcel 33132360Smarcel#include "opt_ip6fw.h" 34132332Smarcel#include "opt_inet.h" 35132332Smarcel#include "opt_inet6.h" 36132332Smarcel#include "opt_ipsec.h" 37132950Sdavidxu 38132950Sdavidxu#include <sys/param.h> 39132950Sdavidxu#include <sys/systm.h> 40132950Sdavidxu#include <sys/malloc.h> 41132950Sdavidxu#include <sys/mbuf.h> 42132950Sdavidxu#include <sys/domain.h> 43132950Sdavidxu#include <sys/protosw.h> 44132950Sdavidxu#include <sys/socket.h> 45132950Sdavidxu#include <sys/errno.h> 46132950Sdavidxu#include <sys/time.h> 47132950Sdavidxu#include <sys/kernel.h> 48132950Sdavidxu#include <sys/syslog.h> 49132950Sdavidxu 50132950Sdavidxu#include <net/if.h> 51132950Sdavidxu#include <net/route.h> 52132950Sdavidxu#include <net/pfil.h> 53132950Sdavidxu 54132950Sdavidxu#include <netinet/in.h> 55132950Sdavidxu#include <netinet/in_var.h> 56132950Sdavidxu#include <netinet/in_systm.h> 57132950Sdavidxu#include <netinet/ip.h> 58132950Sdavidxu#include <netinet/ip_var.h> 59132332Smarcel#include <netinet6/in6_var.h> 60132332Smarcel#include <netinet/ip6.h> 61132332Smarcel#include <netinet6/ip6_var.h> 62132332Smarcel#include <netinet6/scope6_var.h> 63132332Smarcel#include <netinet/icmp6.h> 64132950Sdavidxu#include <netinet6/nd6.h> 65132950Sdavidxu 66132950Sdavidxu#include <netinet/in_pcb.h> 67132950Sdavidxu 68132950Sdavidxu#ifdef IPSEC 69132950Sdavidxu#include <netinet6/ipsec.h> 70132950Sdavidxu#ifdef INET6 71132950Sdavidxu#include <netinet6/ipsec6.h> 72132950Sdavidxu#endif 73132950Sdavidxu#include <netkey/key.h> 74132950Sdavidxu#endif /* IPSEC */ 75132950Sdavidxu 76132950Sdavidxu#ifdef FAST_IPSEC 77132950Sdavidxu#include <netipsec/ipsec.h> 78132950Sdavidxu#include <netipsec/ipsec6.h> 79132950Sdavidxu#include <netipsec/key.h> 80132950Sdavidxu#define IPSEC 81132950Sdavidxu#endif /* FAST_IPSEC */ 82132950Sdavidxu 83132950Sdavidxu#include <netinet6/ip6_fw.h> 84132950Sdavidxu 85132950Sdavidxu#include <net/net_osdep.h> 86132332Smarcel 87132332Smarcel#include <netinet6/ip6protosw.h> 88132332Smarcel 89132332Smarcelstruct route_in6 ip6_forward_rt; 90132332Smarcel 91132950Sdavidxu/* 92132332Smarcel * Forward a packet. If some error occurs return the sender 93132332Smarcel * an icmp packet. Note we can't always generate a meaningful 94132332Smarcel * icmp message because icmp doesn't have a large enough repertoire 95132332Smarcel * of codes and types. 96132332Smarcel * 97132950Sdavidxu * If not forwarding, just drop the packet. This could be confusing 98132332Smarcel * if ipforwarding was zero but some routing protocol was advancing 99132332Smarcel * us as a gateway to somewhere. However, we must let the routing 100132332Smarcel * protocol deal with that. 101132332Smarcel * 102132332Smarcel */ 103132950Sdavidxu 104132332Smarcelvoid 105132332Smarcelip6_forward(m, srcrt) 106132332Smarcel struct mbuf *m; 107132332Smarcel int srcrt; 108132332Smarcel{ 109132950Sdavidxu struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 110132950Sdavidxu struct sockaddr_in6 *dst = NULL; 111132950Sdavidxu struct rtentry *rt = NULL; 112132950Sdavidxu int error, type = 0, code = 0; 113132950Sdavidxu struct mbuf *mcopy = NULL; 114132950Sdavidxu struct ifnet *origifp; /* maybe unnecessary */ 115132950Sdavidxu u_int32_t inzone, outzone; 116132950Sdavidxu struct in6_addr src_in6, dst_in6; 117132332Smarcel#ifdef IPSEC 118 struct secpolicy *sp = NULL; 119 int ipsecrt = 0; 120#endif 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#if !defined(FAST_IPSEC) 132 ipsec6stat.in_polvio++; 133#endif 134 m_freem(m); 135 return; 136 } 137#endif /* IPSEC */ 138 139 /* 140 * Do not forward packets to multicast destination (should be handled 141 * by ip6_mforward(). 142 * Do not forward packets with unspecified source. It was discussed 143 * in July 2000, on the ipngwg mailing list. 144 */ 145 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 146 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 147 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 148 ip6stat.ip6s_cantforward++; 149 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 150 if (ip6_log_time + ip6_log_interval < time_second) { 151 ip6_log_time = time_second; 152 log(LOG_DEBUG, 153 "cannot forward " 154 "from %s to %s nxt %d received on %s\n", 155 ip6_sprintf(&ip6->ip6_src), 156 ip6_sprintf(&ip6->ip6_dst), 157 ip6->ip6_nxt, 158 if_name(m->m_pkthdr.rcvif)); 159 } 160 m_freem(m); 161 return; 162 } 163 164 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 165 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 166 icmp6_error(m, ICMP6_TIME_EXCEEDED, 167 ICMP6_TIME_EXCEED_TRANSIT, 0); 168 return; 169 } 170 ip6->ip6_hlim -= IPV6_HLIMDEC; 171 172 /* 173 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 174 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 175 * we need to generate an ICMP6 message to the src. 176 * Thanks to M_EXT, in most cases copy will not occur. 177 * 178 * It is important to save it before IPsec processing as IPsec 179 * processing may modify the mbuf. 180 */ 181 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 182 183#ifdef IPSEC 184 /* get a security policy for this packet */ 185 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 186 IP_FORWARDING, &error); 187 if (sp == NULL) { 188 ipsec6stat.out_inval++; 189 ip6stat.ip6s_cantforward++; 190 if (mcopy) { 191#if 0 192 /* XXX: what icmp ? */ 193#else 194 m_freem(mcopy); 195#endif 196 } 197 m_freem(m); 198 return; 199 } 200 201 error = 0; 202 203 /* check policy */ 204 switch (sp->policy) { 205 case IPSEC_POLICY_DISCARD: 206 /* 207 * This packet is just discarded. 208 */ 209 ipsec6stat.out_polvio++; 210 ip6stat.ip6s_cantforward++; 211 key_freesp(sp); 212 if (mcopy) { 213#if 0 214 /* XXX: what icmp ? */ 215#else 216 m_freem(mcopy); 217#endif 218 } 219 m_freem(m); 220 return; 221 222 case IPSEC_POLICY_BYPASS: 223 case IPSEC_POLICY_NONE: 224 /* no need to do IPsec. */ 225 key_freesp(sp); 226 goto skip_ipsec; 227 228 case IPSEC_POLICY_IPSEC: 229 if (sp->req == NULL) { 230 /* XXX should be panic ? */ 231 printf("ip6_forward: No IPsec request specified.\n"); 232 ip6stat.ip6s_cantforward++; 233 key_freesp(sp); 234 if (mcopy) { 235#if 0 236 /* XXX: what icmp ? */ 237#else 238 m_freem(mcopy); 239#endif 240 } 241 m_freem(m); 242 return; 243 } 244 /* do IPsec */ 245 break; 246 247 case IPSEC_POLICY_ENTRUST: 248 default: 249 /* should be panic ?? */ 250 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 251 key_freesp(sp); 252 goto skip_ipsec; 253 } 254 255 { 256 struct ipsecrequest *isr = NULL; 257 struct ipsec_output_state state; 258 259 /* 260 * when the kernel forwards a packet, it is not proper to apply 261 * IPsec transport mode to the packet is not proper. this check 262 * avoid from this. 263 * at present, if there is even a transport mode SA request in the 264 * security policy, the kernel does not apply IPsec to the packet. 265 * this check is not enough because the following case is valid. 266 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require; 267 */ 268 for (isr = sp->req; isr; isr = isr->next) { 269 if (isr->saidx.mode == IPSEC_MODE_ANY) 270 goto doipsectunnel; 271 if (isr->saidx.mode == IPSEC_MODE_TUNNEL) 272 goto doipsectunnel; 273 } 274 275 /* 276 * if there's no need for tunnel mode IPsec, skip. 277 */ 278 if (!isr) 279 goto skip_ipsec; 280 281 doipsectunnel: 282 /* 283 * All the extension headers will become inaccessible 284 * (since they can be encrypted). 285 * Don't panic, we need no more updates to extension headers 286 * on inner IPv6 packet (since they are now encapsulated). 287 * 288 * IPv6 [ESP|AH] IPv6 [extension headers] payload 289 */ 290 bzero(&state, sizeof(state)); 291 state.m = m; 292 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 293 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 294 295 error = ipsec6_output_tunnel(&state, sp, 0); 296 297 m = state.m; 298 key_freesp(sp); 299 300 if (error) { 301 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 302 switch (error) { 303 case EHOSTUNREACH: 304 case ENETUNREACH: 305 case EMSGSIZE: 306 case ENOBUFS: 307 case ENOMEM: 308 break; 309 default: 310 printf("ip6_output (ipsec): error code %d\n", error); 311 /* FALLTHROUGH */ 312 case ENOENT: 313 /* don't show these error codes to the user */ 314 break; 315 } 316 ip6stat.ip6s_cantforward++; 317 if (mcopy) { 318#if 0 319 /* XXX: what icmp ? */ 320#else 321 m_freem(mcopy); 322#endif 323 } 324 m_freem(m); 325 return; 326 } 327 328 if (ip6 != mtod(m, struct ip6_hdr *)) { 329 /* 330 * now tunnel mode headers are added. we are originating 331 * packet instead of forwarding the packet. 332 */ 333 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL, 334 NULL); 335 goto freecopy; 336 } 337 338 /* adjust pointer */ 339 dst = (struct sockaddr_in6 *)state.dst; 340 rt = state.ro ? state.ro->ro_rt : NULL; 341 if (dst != NULL && rt != NULL) 342 ipsecrt = 1; 343 } 344 skip_ipsec: 345#endif /* IPSEC */ 346 347#ifdef IPSEC 348 if (ipsecrt) 349 goto skip_routing; 350#endif 351 352 dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; 353 if (!srcrt) { 354 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ 355 if (ip6_forward_rt.ro_rt == 0 || 356 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 357 if (ip6_forward_rt.ro_rt) { 358 RTFREE(ip6_forward_rt.ro_rt); 359 ip6_forward_rt.ro_rt = 0; 360 } 361 362 /* this probably fails but give it a try again */ 363 rtalloc((struct route *)&ip6_forward_rt); 364 } 365 366 if (ip6_forward_rt.ro_rt == 0) { 367 ip6stat.ip6s_noroute++; 368 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 369 if (mcopy) { 370 icmp6_error(mcopy, ICMP6_DST_UNREACH, 371 ICMP6_DST_UNREACH_NOROUTE, 0); 372 } 373 m_freem(m); 374 return; 375 } 376 } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 377 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 378 if (ip6_forward_rt.ro_rt) { 379 RTFREE(ip6_forward_rt.ro_rt); 380 ip6_forward_rt.ro_rt = 0; 381 } 382 bzero(dst, sizeof(*dst)); 383 dst->sin6_len = sizeof(struct sockaddr_in6); 384 dst->sin6_family = AF_INET6; 385 dst->sin6_addr = ip6->ip6_dst; 386 387 rtalloc((struct route *)&ip6_forward_rt); 388 if (ip6_forward_rt.ro_rt == 0) { 389 ip6stat.ip6s_noroute++; 390 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 391 if (mcopy) { 392 icmp6_error(mcopy, ICMP6_DST_UNREACH, 393 ICMP6_DST_UNREACH_NOROUTE, 0); 394 } 395 m_freem(m); 396 return; 397 } 398 } 399 rt = ip6_forward_rt.ro_rt; 400#ifdef IPSEC 401 skip_routing:; 402#endif 403 404 /* 405 * Source scope check: if a packet can't be delivered to its 406 * destination for the reason that the destination is beyond the scope 407 * of the source address, discard the packet and return an icmp6 408 * destination unreachable error with Code 2 (beyond scope of source 409 * address). We use a local copy of ip6_src, since in6_setscope() 410 * will possibly modify its first argument. 411 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] 412 */ 413 src_in6 = ip6->ip6_src; 414 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 415 /* XXX: this should not happen */ 416 ip6stat.ip6s_cantforward++; 417 ip6stat.ip6s_badscope++; 418 m_freem(m); 419 return; 420 } 421 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 422 ip6stat.ip6s_cantforward++; 423 ip6stat.ip6s_badscope++; 424 m_freem(m); 425 return; 426 } 427 if (inzone != outzone 428#ifdef IPSEC 429 && !ipsecrt 430#endif 431 ) { 432 ip6stat.ip6s_cantforward++; 433 ip6stat.ip6s_badscope++; 434 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 435 436 if (ip6_log_time + ip6_log_interval < time_second) { 437 ip6_log_time = time_second; 438 log(LOG_DEBUG, 439 "cannot forward " 440 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 441 ip6_sprintf(&ip6->ip6_src), 442 ip6_sprintf(&ip6->ip6_dst), 443 ip6->ip6_nxt, 444 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 445 } 446 if (mcopy) 447 icmp6_error(mcopy, ICMP6_DST_UNREACH, 448 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 449 m_freem(m); 450 return; 451 } 452 453 /* 454 * Destination scope check: if a packet is going to break the scope 455 * zone of packet's destination address, discard it. This case should 456 * usually be prevented by appropriately-configured routing table, but 457 * we need an explicit check because we may mistakenly forward the 458 * packet to a different zone by (e.g.) a default route. 459 */ 460 dst_in6 = ip6->ip6_dst; 461 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 462 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 463 inzone != outzone) { 464 ip6stat.ip6s_cantforward++; 465 ip6stat.ip6s_badscope++; 466 m_freem(m); 467 return; 468 } 469 470 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) { 471 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 472 if (mcopy) { 473 u_long mtu; 474#ifdef IPSEC 475 struct secpolicy *sp; 476 int ipsecerror; 477 size_t ipsechdrsiz; 478#endif 479 480 mtu = IN6_LINKMTU(rt->rt_ifp); 481#ifdef IPSEC 482 /* 483 * When we do IPsec tunnel ingress, we need to play 484 * with the link value (decrement IPsec header size 485 * from mtu value). The code is much simpler than v4 486 * case, as we have the outgoing interface for 487 * encapsulated packet as "rt->rt_ifp". 488 */ 489 sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 490 IP_FORWARDING, &ipsecerror); 491 if (sp) { 492 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 493 IPSEC_DIR_OUTBOUND, NULL); 494 if (ipsechdrsiz < mtu) 495 mtu -= ipsechdrsiz; 496 } 497 498 /* 499 * if mtu becomes less than minimum MTU, 500 * tell minimum MTU (and I'll need to fragment it). 501 */ 502 if (mtu < IPV6_MMTU) 503 mtu = IPV6_MMTU; 504#endif 505 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 506 } 507 m_freem(m); 508 return; 509 } 510 511 if (rt->rt_flags & RTF_GATEWAY) 512 dst = (struct sockaddr_in6 *)rt->rt_gateway; 513 514 /* 515 * If we are to forward the packet using the same interface 516 * as one we got the packet from, perhaps we should send a redirect 517 * to sender to shortcut a hop. 518 * Only send redirect if source is sending directly to us, 519 * and if packet was not source routed (or has any options). 520 * Also, don't send redirect if forwarding using a route 521 * modified by a redirect. 522 */ 523 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 524#ifdef IPSEC 525 !ipsecrt && 526#endif 527 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 528 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 529 /* 530 * If the incoming interface is equal to the outgoing 531 * one, and the link attached to the interface is 532 * point-to-point, then it will be highly probable 533 * that a routing loop occurs. Thus, we immediately 534 * drop the packet and send an ICMPv6 error message. 535 * 536 * type/code is based on suggestion by Rich Draves. 537 * not sure if it is the best pick. 538 */ 539 icmp6_error(mcopy, ICMP6_DST_UNREACH, 540 ICMP6_DST_UNREACH_ADDR, 0); 541 m_freem(m); 542 return; 543 } 544 type = ND_REDIRECT; 545 } 546 547 /* 548 * Check with the firewall... 549 */ 550 if (ip6_fw_enable && ip6_fw_chk_ptr) { 551 u_short port = 0; 552 /* If ipfw says divert, we have to just drop packet */ 553 if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { 554 m_freem(m); 555 goto freecopy; 556 } 557 if (!m) 558 goto freecopy; 559 } 560 561 /* 562 * Fake scoped addresses. Note that even link-local source or 563 * destinaion can appear, if the originating node just sends the 564 * packet to us (without address resolution for the destination). 565 * Since both icmp6_error and icmp6_redirect_output fill the embedded 566 * link identifiers, we can do this stuff after making a copy for 567 * returning an error. 568 */ 569 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 570 /* 571 * See corresponding comments in ip6_output. 572 * XXX: but is it possible that ip6_forward() sends a packet 573 * to a loopback interface? I don't think so, and thus 574 * I bark here. (jinmei@kame.net) 575 * XXX: it is common to route invalid packets to loopback. 576 * also, the codepath will be visited on use of ::1 in 577 * rthdr. (itojun) 578 */ 579#if 1 580 if (0) 581#else 582 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 583#endif 584 { 585 printf("ip6_forward: outgoing interface is loopback. " 586 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 587 ip6_sprintf(&ip6->ip6_src), 588 ip6_sprintf(&ip6->ip6_dst), 589 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 590 if_name(rt->rt_ifp)); 591 } 592 593 /* we can just use rcvif in forwarding. */ 594 origifp = m->m_pkthdr.rcvif; 595 } 596 else 597 origifp = rt->rt_ifp; 598 /* 599 * clear embedded scope identifiers if necessary. 600 * in6_clearscope will touch the addresses only when necessary. 601 */ 602 in6_clearscope(&ip6->ip6_src); 603 in6_clearscope(&ip6->ip6_dst); 604 605 /* Jump over all PFIL processing if hooks are not active. */ 606 if (inet6_pfil_hook.ph_busy_count == -1) 607 goto pass; 608 609 /* Run through list of hooks for output packets. */ 610 error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL); 611 if (error != 0) 612 goto senderr; 613 if (m == NULL) 614 goto freecopy; 615 ip6 = mtod(m, struct ip6_hdr *); 616 617pass: 618 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 619 if (error) { 620 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 621 ip6stat.ip6s_cantforward++; 622 } else { 623 ip6stat.ip6s_forward++; 624 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 625 if (type) 626 ip6stat.ip6s_redirectsent++; 627 else { 628 if (mcopy) 629 goto freecopy; 630 } 631 } 632 633senderr: 634 if (mcopy == NULL) 635 return; 636 switch (error) { 637 case 0: 638 if (type == ND_REDIRECT) { 639 icmp6_redirect_output(mcopy, rt); 640 return; 641 } 642 goto freecopy; 643 644 case EMSGSIZE: 645 /* xxx MTU is constant in PPP? */ 646 goto freecopy; 647 648 case ENOBUFS: 649 /* Tell source to slow down like source quench in IP? */ 650 goto freecopy; 651 652 case ENETUNREACH: /* shouldn't happen, checked above */ 653 case EHOSTUNREACH: 654 case ENETDOWN: 655 case EHOSTDOWN: 656 default: 657 type = ICMP6_DST_UNREACH; 658 code = ICMP6_DST_UNREACH_ADDR; 659 break; 660 } 661 icmp6_error(mcopy, type, code, 0); 662 return; 663 664 freecopy: 665 m_freem(mcopy); 666 return; 667} 668