1/* 2 * Copyright (c) 2009-2011 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29/* $FreeBSD: src/sys/netinet6/ip6_forward.c,v 1.16 2002/10/16 02:25:05 sam Exp $ */ 30/* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */ 31 32/* 33 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 3. Neither the name of the project nor the names of its contributors 45 * may be used to endorse or promote products derived from this software 46 * without specific prior written permission. 47 * 48 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 51 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 58 * SUCH DAMAGE. 59 */ 60 61 62#include <sys/param.h> 63#include <sys/systm.h> 64#include <sys/malloc.h> 65#include <sys/mbuf.h> 66#include <sys/domain.h> 67#include <sys/protosw.h> 68#include <sys/socket.h> 69#include <sys/errno.h> 70#include <sys/time.h> 71#include <sys/kernel.h> 72#include <sys/syslog.h> 73 74#include <net/if.h> 75#include <net/route.h> 76 77#include <netinet/in.h> 78#include <netinet/in_var.h> 79#include <netinet/in_systm.h> 80#include <netinet/ip.h> 81#include <netinet/ip_var.h> 82#include <netinet6/in6_var.h> 83#include <netinet/ip6.h> 84#include <netinet6/ip6_var.h> 85#include <netinet/icmp6.h> 86#include <netinet6/nd6.h> 87#include <netinet6/scope6_var.h> 88 89#include <netinet/in_pcb.h> 90 91#if IPSEC 92#include <netinet6/ipsec.h> 93#if INET6 94#include <netinet6/ipsec6.h> 95#endif 96#include <netkey/key.h> 97extern int ipsec_bypass; 98#endif /* IPSEC */ 99 100#include <netinet6/ip6_fw.h> 101 102#include <net/net_osdep.h> 103 104#if PF 105#include <net/pfvar.h> 106#endif /* PF */ 107 108/* 109 * Forward a packet. If some error occurs return the sender 110 * an icmp packet. Note we can't always generate a meaningful 111 * icmp message because icmp doesn't have a large enough repertoire 112 * of codes and types. 113 * 114 * If not forwarding, just drop the packet. This could be confusing 115 * if ipforwarding was zero but some routing protocol was advancing 116 * us as a gateway to somewhere. However, we must let the routing 117 * protocol deal with that. 118 * 119 */ 120 121struct mbuf * 122ip6_forward(struct mbuf *m, struct route_in6 *ip6forward_rt, 123 int srcrt) 124{ 125 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 126 struct sockaddr_in6 *dst; 127 struct rtentry *rt; 128 int error, type = 0, code = 0; 129 boolean_t proxy = FALSE; 130 struct mbuf *mcopy = NULL; 131 struct ifnet *ifp, *origifp; /* maybe unnecessary */ 132 u_int32_t inzone, outzone; 133 struct in6_addr src_in6, dst_in6; 134#if IPSEC 135 struct secpolicy *sp = NULL; 136#endif 137 struct timeval timenow; 138 unsigned int ifscope = IFSCOPE_NONE; 139#if PF 140 struct pf_mtag *pf_mtag; 141#endif /* PF */ 142 143 getmicrotime(&timenow); 144#if PF 145 pf_mtag = pf_find_mtag(m); 146 if (pf_mtag != NULL && pf_mtag->pftag_rtableid != IFSCOPE_NONE) 147 ifscope = pf_mtag->pftag_rtableid; 148 149 /* 150 * If the caller provides a route which is on a different interface 151 * than the one specified for scoped forwarding, discard the route 152 * and do a lookup below. 153 */ 154 if (ifscope != IFSCOPE_NONE && (rt = ip6forward_rt->ro_rt) != NULL) { 155 RT_LOCK(rt); 156 if (rt->rt_ifp->if_index != ifscope) { 157 RT_UNLOCK(rt); 158 rtfree(rt); 159 rt = ip6forward_rt->ro_rt = NULL; 160 } else { 161 RT_UNLOCK(rt); 162 } 163 } 164#endif /* PF */ 165 166#if IPSEC 167 /* 168 * Check AH/ESP integrity. 169 */ 170 /* 171 * Don't increment ip6s_cantforward because this is the check 172 * before forwarding packet actually. 173 */ 174 if (ipsec_bypass == 0) { 175 if (ipsec6_in_reject(m, NULL)) { 176 IPSEC_STAT_INCREMENT(ipsec6stat.in_polvio); 177 m_freem(m); 178 return (NULL); 179 } 180 } 181#endif /*IPSEC*/ 182 183 /* 184 * Do not forward packets to multicast destination (should be handled 185 * by ip6_mforward(). 186 * Do not forward packets with unspecified source. It was discussed 187 * in July 2000, on ipngwg mailing list. 188 */ 189 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 190 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 191 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 192 ip6stat.ip6s_cantforward++; 193 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 194 if (ip6_log_time + ip6_log_interval < timenow.tv_sec) { 195 ip6_log_time = timenow.tv_sec; 196 log(LOG_DEBUG, 197 "cannot forward " 198 "from %s to %s nxt %d received on %s\n", 199 ip6_sprintf(&ip6->ip6_src), 200 ip6_sprintf(&ip6->ip6_dst), 201 ip6->ip6_nxt, 202 if_name(m->m_pkthdr.rcvif)); 203 } 204 m_freem(m); 205 return (NULL); 206 } 207 208 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 209 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 210 icmp6_error(m, ICMP6_TIME_EXCEEDED, 211 ICMP6_TIME_EXCEED_TRANSIT, 0); 212 return (NULL); 213 } 214 215 /* 216 * See if the destination is a proxied address, and if so pretend 217 * that it's for us. This is mostly to handle NUD probes against 218 * the proxied addresses. We filter for ICMPv6 here and will let 219 * icmp6_input handle the rest. 220 */ 221 if (!srcrt && nd6_prproxy) { 222 VERIFY(!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)); 223 proxy = nd6_prproxy_isours(m, ip6, ip6forward_rt, ifscope); 224 /* 225 * Don't update hop limit while proxying; RFC 4389 4.1. 226 * Also skip IPsec forwarding path processing as this 227 * packet is not to be forwarded. 228 */ 229 if (proxy) 230 goto skip_ipsec; 231 } 232 233 ip6->ip6_hlim -= IPV6_HLIMDEC; 234 235 /* 236 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 237 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 238 * we need to generate an ICMP6 message to the src. 239 * Thanks to M_EXT, in most cases copy will not occur. 240 * 241 * It is important to save it before IPsec processing as IPsec 242 * processing may modify the mbuf. 243 */ 244 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 245 246#if IPSEC 247 if (ipsec_bypass != 0) 248 goto skip_ipsec; 249 /* get a security policy for this packet */ 250 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, 251 &error); 252 if (sp == NULL) { 253 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval); 254 ip6stat.ip6s_cantforward++; 255 if (mcopy) { 256#if 0 257 /* XXX: what icmp ? */ 258#else 259 m_freem(mcopy); 260#endif 261 } 262 m_freem(m); 263 return (NULL); 264 } 265 266 error = 0; 267 268 /* check policy */ 269 switch (sp->policy) { 270 case IPSEC_POLICY_DISCARD: 271 case IPSEC_POLICY_GENERATE: 272 /* 273 * This packet is just discarded. 274 */ 275 IPSEC_STAT_INCREMENT(ipsec6stat.out_polvio); 276 ip6stat.ip6s_cantforward++; 277 key_freesp(sp, KEY_SADB_UNLOCKED); 278 if (mcopy) { 279#if 0 280 /* XXX: what icmp ? */ 281#else 282 m_freem(mcopy); 283#endif 284 } 285 m_freem(m); 286 return (NULL); 287 288 case IPSEC_POLICY_BYPASS: 289 case IPSEC_POLICY_NONE: 290 /* no need to do IPsec. */ 291 key_freesp(sp, KEY_SADB_UNLOCKED); 292 goto skip_ipsec; 293 294 case IPSEC_POLICY_IPSEC: 295 if (sp->req == NULL) { 296 /* XXX should be panic ? */ 297 printf("ip6_forward: No IPsec request specified.\n"); 298 ip6stat.ip6s_cantforward++; 299 key_freesp(sp, KEY_SADB_UNLOCKED); 300 if (mcopy) { 301#if 0 302 /* XXX: what icmp ? */ 303#else 304 m_freem(mcopy); 305#endif 306 } 307 m_freem(m); 308 return (NULL); 309 } 310 /* do IPsec */ 311 break; 312 313 case IPSEC_POLICY_ENTRUST: 314 default: 315 /* should be panic ?? */ 316 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 317 key_freesp(sp, KEY_SADB_UNLOCKED); 318 goto skip_ipsec; 319 } 320 321 { 322 struct ipsec_output_state state; 323 324 /* 325 * All the extension headers will become inaccessible 326 * (since they can be encrypted). 327 * Don't panic, we need no more updates to extension headers 328 * on inner IPv6 packet (since they are now encapsulated). 329 * 330 * IPv6 [ESP|AH] IPv6 [extension headers] payload 331 */ 332 bzero(&state, sizeof(state)); 333 state.m = m; 334 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 335 336 error = ipsec6_output_tunnel(&state, sp, 0); 337 key_freesp(sp, KEY_SADB_UNLOCKED); 338 if (state.tunneled == 4) 339 return (NULL); /* packet is gone - sent over IPv4 */ 340 341 m = state.m; 342 if (state.ro.ro_rt) { 343 rtfree(state.ro.ro_rt); 344 state.ro.ro_rt = NULL; 345 } 346 if (error) { 347 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 348 switch (error) { 349 case EHOSTUNREACH: 350 case ENETUNREACH: 351 case EMSGSIZE: 352 case ENOBUFS: 353 case ENOMEM: 354 break; 355 default: 356 printf("ip6_output (ipsec): error code %d\n", error); 357 /* fall through */ 358 case ENOENT: 359 /* don't show these error codes to the user */ 360 break; 361 } 362 ip6stat.ip6s_cantforward++; 363 if (mcopy) { 364#if 0 365 /* XXX: what icmp ? */ 366#else 367 m_freem(mcopy); 368#endif 369 } 370 m_freem(m); 371 return (NULL); 372 } 373 } 374 skip_ipsec: 375#endif /* IPSEC */ 376 377 dst = (struct sockaddr_in6 *)&ip6forward_rt->ro_dst; 378 if ((rt = ip6forward_rt->ro_rt) != NULL) { 379 RT_LOCK(rt); 380 /* Take an extra ref for ourselves */ 381 RT_ADDREF_LOCKED(rt); 382 } 383 384 if (!srcrt) { 385 /* 386 * ip6forward_rt->ro_dst.sin6_addr is equal to ip6->ip6_dst 387 */ 388 if (rt == NULL || !(rt->rt_flags & RTF_UP) || 389 rt->generation_id != route_generation) { 390 if (rt != NULL) { 391 /* Release extra ref */ 392 RT_REMREF_LOCKED(rt); 393 RT_UNLOCK(rt); 394 rtfree(rt); 395 ip6forward_rt->ro_rt = NULL; 396 } 397 /* this probably fails but give it a try again */ 398 rtalloc_scoped_ign((struct route *)ip6forward_rt, 399 RTF_PRCLONING, ifscope); 400 if ((rt = ip6forward_rt->ro_rt) != NULL) { 401 RT_LOCK(rt); 402 /* Take an extra ref for ourselves */ 403 RT_ADDREF_LOCKED(rt); 404 } 405 } 406 407 if (rt == NULL) { 408 ip6stat.ip6s_noroute++; 409 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 410 if (mcopy) 411 icmp6_error(mcopy, ICMP6_DST_UNREACH, 412 ICMP6_DST_UNREACH_NOROUTE, 0); 413 m_freem(m); 414 return (NULL); 415 } 416 RT_LOCK_ASSERT_HELD(rt); 417 } else if (rt == NULL || !(rt->rt_flags & RTF_UP) || 418 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr) || 419 rt->generation_id != route_generation) { 420 if (rt != NULL) { 421 /* Release extra ref */ 422 RT_REMREF_LOCKED(rt); 423 RT_UNLOCK(rt); 424 rtfree(rt); 425 ip6forward_rt->ro_rt = NULL; 426 } 427 bzero(dst, sizeof(*dst)); 428 dst->sin6_len = sizeof(struct sockaddr_in6); 429 dst->sin6_family = AF_INET6; 430 dst->sin6_addr = ip6->ip6_dst; 431 432 rtalloc_scoped_ign((struct route *)ip6forward_rt, 433 RTF_PRCLONING, ifscope); 434 if ((rt = ip6forward_rt->ro_rt) == NULL) { 435 ip6stat.ip6s_noroute++; 436 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 437 if (mcopy) 438 icmp6_error(mcopy, ICMP6_DST_UNREACH, 439 ICMP6_DST_UNREACH_NOROUTE, 0); 440 m_freem(m); 441 return (NULL); 442 } 443 RT_LOCK(rt); 444 /* Take an extra ref for ourselves */ 445 RT_ADDREF_LOCKED(rt); 446 } 447 448 /* 449 * Source scope check: if a packet can't be delivered to its 450 * destination for the reason that the destination is beyond the scope 451 * of the source address, discard the packet and return an icmp6 452 * destination unreachable error with Code 2 (beyond scope of source 453 * address) unless we are proxying (source address is link local 454 * for NUDs.) We use a local copy of ip6_src, since in6_setscope() 455 * will possibly modify its first argument. 456 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] 457 */ 458 src_in6 = ip6->ip6_src; 459 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 460 /* XXX: this should not happen */ 461 ip6stat.ip6s_cantforward++; 462 ip6stat.ip6s_badscope++; 463 m_freem(m); 464 return (NULL); 465 } 466 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 467 ip6stat.ip6s_cantforward++; 468 ip6stat.ip6s_badscope++; 469 m_freem(m); 470 return (NULL); 471 } 472 473 if (inzone != outzone && !proxy) { 474 ip6stat.ip6s_cantforward++; 475 ip6stat.ip6s_badscope++; 476 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 477 478 if (ip6_log_time + ip6_log_interval < timenow.tv_sec) { 479 ip6_log_time = timenow.tv_sec; 480 log(LOG_DEBUG, 481 "cannot forward " 482 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 483 ip6_sprintf(&ip6->ip6_src), 484 ip6_sprintf(&ip6->ip6_dst), 485 ip6->ip6_nxt, 486 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 487 } 488 /* Release extra ref */ 489 RT_REMREF_LOCKED(rt); 490 RT_UNLOCK(rt); 491 if (mcopy) { 492 icmp6_error(mcopy, ICMP6_DST_UNREACH, 493 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 494 } 495 m_freem(m); 496 return (NULL); 497 } 498 499 /* 500 * Destination scope check: if a packet is going to break the scope 501 * zone of packet's destination address, discard it. This case should 502 * usually be prevented by appropriately-configured routing table, but 503 * we need an explicit check because we may mistakenly forward the 504 * packet to a different zone by (e.g.) a default route. 505 */ 506 dst_in6 = ip6->ip6_dst; 507 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 508 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 509 inzone != outzone) { 510 ip6stat.ip6s_cantforward++; 511 ip6stat.ip6s_badscope++; 512 m_freem(m); 513 return (NULL); 514 } 515 516 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 517 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 518 if (mcopy) { 519 uint32_t mtu; 520#if IPSEC 521 struct secpolicy *sp2; 522 int ipsecerror; 523 size_t ipsechdrsiz; 524#endif 525 526 mtu = rt->rt_ifp->if_mtu; 527#if IPSEC 528 /* 529 * When we do IPsec tunnel ingress, we need to play 530 * with the link value (decrement IPsec header size 531 * from mtu value). The code is much simpler than v4 532 * case, as we have the outgoing interface for 533 * encapsulated packet as "rt->rt_ifp". 534 */ 535 sp2 = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 536 IP_FORWARDING, &ipsecerror); 537 if (sp2) { 538 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 539 IPSEC_DIR_OUTBOUND, NULL); 540 if (ipsechdrsiz < mtu) 541 mtu -= ipsechdrsiz; 542 key_freesp(sp2, KEY_SADB_UNLOCKED); 543 } 544 /* 545 * if mtu becomes less than minimum MTU, 546 * tell minimum MTU (and I'll need to fragment it). 547 */ 548 if (mtu < IPV6_MMTU) 549 mtu = IPV6_MMTU; 550#endif 551 /* Release extra ref */ 552 RT_REMREF_LOCKED(rt); 553 RT_UNLOCK(rt); 554 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 555 } else { 556 /* Release extra ref */ 557 RT_REMREF_LOCKED(rt); 558 RT_UNLOCK(rt); 559 } 560 m_freem(m); 561 return (NULL); 562 } 563 564 if (rt->rt_flags & RTF_GATEWAY) 565 dst = (struct sockaddr_in6 *)(void *)rt->rt_gateway; 566 567 /* 568 * If we are to forward the packet using the same interface 569 * as one we got the packet from, perhaps we should send a redirect 570 * to sender to shortcut a hop. 571 * Only send redirect if source is sending directly to us, 572 * and if packet was not source routed (or has any options). 573 * Also, don't send redirect if forwarding using a route 574 * modified by a redirect. 575 */ 576 if (!proxy && 577 ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 578 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 579 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 580 /* 581 * If the incoming interface is equal to the outgoing 582 * one, and the link attached to the interface is 583 * point-to-point, then it will be highly probable 584 * that a routing loop occurs. Thus, we immediately 585 * drop the packet and send an ICMPv6 error message. 586 * 587 * type/code is based on suggestion by Rich Draves. 588 * not sure if it is the best pick. 589 */ 590 RT_REMREF_LOCKED(rt); /* Release extra ref */ 591 RT_UNLOCK(rt); 592 icmp6_error(mcopy, ICMP6_DST_UNREACH, 593 ICMP6_DST_UNREACH_ADDR, 0); 594 m_freem(m); 595 return (NULL); 596 } 597 type = ND_REDIRECT; 598 } 599 600#if IPFW2 601 /* 602 * Check with the firewall... 603 */ 604 if (ip6_fw_enable && ip6_fw_chk_ptr) { 605 u_short port = 0; 606 ifp = rt->rt_ifp; 607 /* Drop the lock but retain the extra ref */ 608 RT_UNLOCK(rt); 609 /* If ipfw says divert, we have to just drop packet */ 610 if (ip6_fw_chk_ptr(&ip6, ifp, &port, &m)) { 611 m_freem(m); 612 goto freecopy; 613 } 614 if (!m) { 615 goto freecopy; 616 } 617 /* We still have the extra ref on rt */ 618 RT_LOCK(rt); 619 } 620#endif 621 622 /* 623 * Fake scoped addresses. Note that even link-local source or 624 * destinaion can appear, if the originating node just sends the 625 * packet to us (without address resolution for the destination). 626 * Since both icmp6_error and icmp6_redirect_output fill the embedded 627 * link identifiers, we can do this stuff after making a copy for 628 * returning an error. 629 */ 630 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 631 /* 632 * See corresponding comments in ip6_output. 633 * XXX: but is it possible that ip6_forward() sends a packet 634 * to a loopback interface? I don't think so, and thus 635 * I bark here. (jinmei@kame.net) 636 * XXX: it is common to route invalid packets to loopback. 637 * also, the codepath will be visited on use of ::1 in 638 * rthdr. (itojun) 639 */ 640#if 1 641 if (0) 642#else 643 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 644#endif 645 { 646 printf("ip6_forward: outgoing interface is loopback. " 647 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 648 ip6_sprintf(&ip6->ip6_src), 649 ip6_sprintf(&ip6->ip6_dst), 650 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 651 if_name(rt->rt_ifp)); 652 } 653 654 /* we can just use rcvif in forwarding. */ 655 origifp = m->m_pkthdr.rcvif; 656 } 657 else 658 origifp = rt->rt_ifp; 659 /* 660 * clear embedded scope identifiers if necessary. 661 * in6_clearscope will touch the addresses only when necessary. 662 */ 663 in6_clearscope(&ip6->ip6_src); 664 in6_clearscope(&ip6->ip6_dst); 665 666 ifp = rt->rt_ifp; 667 /* Drop the lock but retain the extra ref */ 668 RT_UNLOCK(rt); 669 670 /* 671 * If this is to be processed locally, let ip6_input have it. 672 */ 673 if (proxy) { 674 VERIFY(m->m_pkthdr.aux_flags & MAUXF_PROXY_DST); 675 /* Release extra ref */ 676 RT_REMREF(rt); 677 if (mcopy != NULL) 678 m_freem(mcopy); 679 return (m); 680 } 681 682#if PF 683 /* Invoke outbound packet filter */ 684 error = pf_af_hook(ifp, NULL, &m, AF_INET6, FALSE, NULL); 685 686 if (error != 0 || m == NULL) { 687 if (m != NULL) { 688 panic("%s: unexpected packet %p\n", __func__, m); 689 /* NOTREACHED */ 690 } 691 /* Already freed by callee */ 692 goto senderr; 693 } 694 ip6 = mtod(m, struct ip6_hdr *); 695#endif /* PF */ 696 697 error = nd6_output(ifp, origifp, m, dst, rt, NULL); 698 if (error) { 699 in6_ifstat_inc(ifp, ifs6_out_discard); 700 ip6stat.ip6s_cantforward++; 701 } else { 702 ip6stat.ip6s_forward++; 703 in6_ifstat_inc(ifp, ifs6_out_forward); 704 if (type) 705 ip6stat.ip6s_redirectsent++; 706 else { 707 if (mcopy) { 708 goto freecopy; 709 } 710 } 711 } 712#if PF 713senderr: 714#endif /* PF */ 715 if (mcopy == NULL) { 716 /* Release extra ref */ 717 RT_REMREF(rt); 718 return (NULL); 719 } 720 switch (error) { 721 case 0: 722#if 1 723 if (type == ND_REDIRECT) { 724 icmp6_redirect_output(mcopy, rt); 725 /* Release extra ref */ 726 RT_REMREF(rt); 727 return (NULL); 728 } 729#endif 730 goto freecopy; 731 732 case EMSGSIZE: 733 /* xxx MTU is constant in PPP? */ 734 goto freecopy; 735 736 case ENOBUFS: 737 /* Tell source to slow down like source quench in IP? */ 738 goto freecopy; 739 740 case ENETUNREACH: /* shouldn't happen, checked above */ 741 case EHOSTUNREACH: 742 case ENETDOWN: 743 case EHOSTDOWN: 744 default: 745 type = ICMP6_DST_UNREACH; 746 code = ICMP6_DST_UNREACH_ADDR; 747 break; 748 } 749 icmp6_error(mcopy, type, code, 0); 750 /* Release extra ref */ 751 RT_REMREF(rt); 752 return (NULL); 753 754 freecopy: 755 m_freem(mcopy); 756 /* Release extra ref */ 757 RT_REMREF(rt); 758 return (NULL); 759} 760