1/* 2 * Copyright (c) 2009-2013 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, *rcvifp, *origifp; /* maybe unnecessary */ 132 u_int32_t inzone, outzone, len; 133 struct in6_addr src_in6, dst_in6; 134 uint64_t curtime = net_uptime(); 135#if IPSEC 136 struct secpolicy *sp = NULL; 137#endif 138 unsigned int ifscope = IFSCOPE_NONE; 139#if PF 140 struct pf_mtag *pf_mtag; 141#endif /* PF */ 142 143 /* 144 * In the prefix proxying case, the route to the proxied node normally 145 * gets created by nd6_prproxy_ns_output(), as part of forwarding a 146 * NS (NUD/AR) packet to the proxied node. In the event that such 147 * packet did not arrive in time before the correct route gets created, 148 * ip6_input() would have performed a rtalloc() which most likely will 149 * create the wrong cloned route; this route points back to the same 150 * interface as the inbound interface, since the parent non-scoped 151 * prefix route points there. Therefore we check if that is the case 152 * and perform the necessary fixup to get the correct route installed. 153 */ 154 if (!srcrt && nd6_prproxy && 155 (rt = ip6forward_rt->ro_rt) != NULL && (rt->rt_flags & RTF_PROXY)) { 156 nd6_proxy_find_fwdroute(m->m_pkthdr.rcvif, ip6forward_rt); 157 if ((rt = ip6forward_rt->ro_rt) != NULL) 158 ifscope = rt->rt_ifp->if_index; 159 } 160 161#if PF 162 pf_mtag = pf_find_mtag(m); 163 if (pf_mtag != NULL && pf_mtag->pftag_rtableid != IFSCOPE_NONE) 164 ifscope = pf_mtag->pftag_rtableid; 165 166 /* 167 * If the caller provides a route which is on a different interface 168 * than the one specified for scoped forwarding, discard the route 169 * and do a lookup below. 170 */ 171 if (ifscope != IFSCOPE_NONE && (rt = ip6forward_rt->ro_rt) != NULL) { 172 RT_LOCK(rt); 173 if (rt->rt_ifp->if_index != ifscope) { 174 RT_UNLOCK(rt); 175 ROUTE_RELEASE(ip6forward_rt); 176 rt = NULL; 177 } else { 178 RT_UNLOCK(rt); 179 } 180 } 181#endif /* PF */ 182 183#if IPSEC 184 /* 185 * Check AH/ESP integrity. 186 */ 187 /* 188 * Don't increment ip6s_cantforward because this is the check 189 * before forwarding packet actually. 190 */ 191 if (ipsec_bypass == 0) { 192 if (ipsec6_in_reject(m, NULL)) { 193 IPSEC_STAT_INCREMENT(ipsec6stat.in_polvio); 194 m_freem(m); 195 return (NULL); 196 } 197 } 198#endif /*IPSEC*/ 199 200 /* 201 * Do not forward packets to multicast destination (should be handled 202 * by ip6_mforward(). 203 * Do not forward packets with unspecified source. It was discussed 204 * in July 2000, on ipngwg mailing list. 205 */ 206 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 207 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 208 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 209 ip6stat.ip6s_cantforward++; 210 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 211 if (ip6_log_time + ip6_log_interval < curtime) { 212 ip6_log_time = curtime; 213 log(LOG_DEBUG, 214 "cannot forward " 215 "from %s to %s nxt %d received on %s\n", 216 ip6_sprintf(&ip6->ip6_src), 217 ip6_sprintf(&ip6->ip6_dst), 218 ip6->ip6_nxt, 219 if_name(m->m_pkthdr.rcvif)); 220 } 221 m_freem(m); 222 return (NULL); 223 } 224 225 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 226 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 227 icmp6_error(m, ICMP6_TIME_EXCEEDED, 228 ICMP6_TIME_EXCEED_TRANSIT, 0); 229 return (NULL); 230 } 231 232 /* 233 * See if the destination is a proxied address, and if so pretend 234 * that it's for us. This is mostly to handle NUD probes against 235 * the proxied addresses. We filter for ICMPv6 here and will let 236 * icmp6_input handle the rest. 237 */ 238 if (!srcrt && nd6_prproxy) { 239 VERIFY(!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)); 240 proxy = nd6_prproxy_isours(m, ip6, ip6forward_rt, ifscope); 241 /* 242 * Don't update hop limit while proxying; RFC 4389 4.1. 243 * Also skip IPsec forwarding path processing as this 244 * packet is not to be forwarded. 245 */ 246 if (proxy) 247 goto skip_ipsec; 248 } 249 250 ip6->ip6_hlim -= IPV6_HLIMDEC; 251 252 /* 253 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 254 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 255 * we need to generate an ICMP6 message to the src. 256 * Thanks to M_EXT, in most cases copy will not occur. 257 * 258 * It is important to save it before IPsec processing as IPsec 259 * processing may modify the mbuf. 260 */ 261 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 262 263#if IPSEC 264 if (ipsec_bypass != 0) 265 goto skip_ipsec; 266 /* get a security policy for this packet */ 267 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, 268 &error); 269 if (sp == NULL) { 270 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval); 271 ip6stat.ip6s_cantforward++; 272 if (mcopy) { 273#if 0 274 /* XXX: what icmp ? */ 275#else 276 m_freem(mcopy); 277#endif 278 } 279 m_freem(m); 280 return (NULL); 281 } 282 283 error = 0; 284 285 /* check policy */ 286 switch (sp->policy) { 287 case IPSEC_POLICY_DISCARD: 288 case IPSEC_POLICY_GENERATE: 289 /* 290 * This packet is just discarded. 291 */ 292 IPSEC_STAT_INCREMENT(ipsec6stat.out_polvio); 293 ip6stat.ip6s_cantforward++; 294 key_freesp(sp, KEY_SADB_UNLOCKED); 295 if (mcopy) { 296#if 0 297 /* XXX: what icmp ? */ 298#else 299 m_freem(mcopy); 300#endif 301 } 302 m_freem(m); 303 return (NULL); 304 305 case IPSEC_POLICY_BYPASS: 306 case IPSEC_POLICY_NONE: 307 /* no need to do IPsec. */ 308 key_freesp(sp, KEY_SADB_UNLOCKED); 309 goto skip_ipsec; 310 311 case IPSEC_POLICY_IPSEC: 312 if (sp->req == NULL) { 313 /* XXX should be panic ? */ 314 printf("ip6_forward: No IPsec request specified.\n"); 315 ip6stat.ip6s_cantforward++; 316 key_freesp(sp, KEY_SADB_UNLOCKED); 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 (NULL); 326 } 327 /* do IPsec */ 328 break; 329 330 case IPSEC_POLICY_ENTRUST: 331 default: 332 /* should be panic ?? */ 333 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 334 key_freesp(sp, KEY_SADB_UNLOCKED); 335 goto skip_ipsec; 336 } 337 338 { 339 struct ipsec_output_state state; 340 341 /* 342 * All the extension headers will become inaccessible 343 * (since they can be encrypted). 344 * Don't panic, we need no more updates to extension headers 345 * on inner IPv6 packet (since they are now encapsulated). 346 * 347 * IPv6 [ESP|AH] IPv6 [extension headers] payload 348 */ 349 bzero(&state, sizeof(state)); 350 state.m = m; 351 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 352 353 error = ipsec6_output_tunnel(&state, sp, 0); 354 key_freesp(sp, KEY_SADB_UNLOCKED); 355 if (state.tunneled == 4) { 356 ROUTE_RELEASE(&state.ro); 357 return (NULL); /* packet is gone - sent over IPv4 */ 358 } 359 360 m = state.m; 361 ROUTE_RELEASE(&state.ro); 362 363 if (error) { 364 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 365 switch (error) { 366 case EHOSTUNREACH: 367 case ENETUNREACH: 368 case EMSGSIZE: 369 case ENOBUFS: 370 case ENOMEM: 371 break; 372 default: 373 printf("ip6_output (ipsec): error code %d\n", error); 374 /* fall through */ 375 case ENOENT: 376 /* don't show these error codes to the user */ 377 break; 378 } 379 ip6stat.ip6s_cantforward++; 380 if (mcopy) { 381#if 0 382 /* XXX: what icmp ? */ 383#else 384 m_freem(mcopy); 385#endif 386 } 387 m_freem(m); 388 return (NULL); 389 } 390 } 391#endif /* IPSEC */ 392 skip_ipsec: 393 394 dst = (struct sockaddr_in6 *)&ip6forward_rt->ro_dst; 395 if ((rt = ip6forward_rt->ro_rt) != NULL) { 396 RT_LOCK(rt); 397 /* Take an extra ref for ourselves */ 398 RT_ADDREF_LOCKED(rt); 399 } 400 401 VERIFY(rt == NULL || rt == ip6forward_rt->ro_rt); 402 if (!srcrt) { 403 /* 404 * ip6forward_rt->ro_dst.sin6_addr is equal to ip6->ip6_dst 405 */ 406 if (ROUTE_UNUSABLE(ip6forward_rt)) { 407 if (rt != NULL) { 408 /* Release extra ref */ 409 RT_REMREF_LOCKED(rt); 410 RT_UNLOCK(rt); 411 } 412 ROUTE_RELEASE(ip6forward_rt); 413 414 /* this probably fails but give it a try again */ 415 rtalloc_scoped_ign((struct route *)ip6forward_rt, 416 RTF_PRCLONING, ifscope); 417 if ((rt = ip6forward_rt->ro_rt) != NULL) { 418 RT_LOCK(rt); 419 /* Take an extra ref for ourselves */ 420 RT_ADDREF_LOCKED(rt); 421 } 422 } 423 424 if (rt == NULL) { 425 ip6stat.ip6s_noroute++; 426 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 427 if (mcopy) 428 icmp6_error(mcopy, ICMP6_DST_UNREACH, 429 ICMP6_DST_UNREACH_NOROUTE, 0); 430 m_freem(m); 431 return (NULL); 432 } 433 RT_LOCK_ASSERT_HELD(rt); 434 } else if (ROUTE_UNUSABLE(ip6forward_rt) || 435 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 436 if (rt != NULL) { 437 /* Release extra ref */ 438 RT_REMREF_LOCKED(rt); 439 RT_UNLOCK(rt); 440 } 441 ROUTE_RELEASE(ip6forward_rt); 442 443 bzero(dst, sizeof(*dst)); 444 dst->sin6_len = sizeof(struct sockaddr_in6); 445 dst->sin6_family = AF_INET6; 446 dst->sin6_addr = ip6->ip6_dst; 447 448 rtalloc_scoped_ign((struct route *)ip6forward_rt, 449 RTF_PRCLONING, ifscope); 450 if ((rt = ip6forward_rt->ro_rt) == NULL) { 451 ip6stat.ip6s_noroute++; 452 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 453 if (mcopy) 454 icmp6_error(mcopy, ICMP6_DST_UNREACH, 455 ICMP6_DST_UNREACH_NOROUTE, 0); 456 m_freem(m); 457 return (NULL); 458 } 459 RT_LOCK(rt); 460 /* Take an extra ref for ourselves */ 461 RT_ADDREF_LOCKED(rt); 462 } 463 464 /* 465 * Source scope check: if a packet can't be delivered to its 466 * destination for the reason that the destination is beyond the scope 467 * of the source address, discard the packet and return an icmp6 468 * destination unreachable error with Code 2 (beyond scope of source 469 * address) unless we are proxying (source address is link local 470 * for NUDs.) We use a local copy of ip6_src, since in6_setscope() 471 * will possibly modify its first argument. 472 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] 473 */ 474 src_in6 = ip6->ip6_src; 475 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 476 /* XXX: this should not happen */ 477 ip6stat.ip6s_cantforward++; 478 ip6stat.ip6s_badscope++; 479 m_freem(m); 480 return (NULL); 481 } 482 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 483 ip6stat.ip6s_cantforward++; 484 ip6stat.ip6s_badscope++; 485 m_freem(m); 486 return (NULL); 487 } 488 489 if (inzone != outzone && !proxy) { 490 ip6stat.ip6s_cantforward++; 491 ip6stat.ip6s_badscope++; 492 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 493 494 if (ip6_log_time + ip6_log_interval < curtime) { 495 ip6_log_time = curtime; 496 log(LOG_DEBUG, 497 "cannot forward " 498 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 499 ip6_sprintf(&ip6->ip6_src), 500 ip6_sprintf(&ip6->ip6_dst), 501 ip6->ip6_nxt, 502 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 503 } 504 /* Release extra ref */ 505 RT_REMREF_LOCKED(rt); 506 RT_UNLOCK(rt); 507 if (mcopy) { 508 icmp6_error(mcopy, ICMP6_DST_UNREACH, 509 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 510 } 511 m_freem(m); 512 return (NULL); 513 } 514 515 /* 516 * Destination scope check: if a packet is going to break the scope 517 * zone of packet's destination address, discard it. This case should 518 * usually be prevented by appropriately-configured routing table, but 519 * we need an explicit check because we may mistakenly forward the 520 * packet to a different zone by (e.g.) a default route. 521 */ 522 dst_in6 = ip6->ip6_dst; 523 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 524 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 525 inzone != outzone) { 526 ip6stat.ip6s_cantforward++; 527 ip6stat.ip6s_badscope++; 528 m_freem(m); 529 return (NULL); 530 } 531 532 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 533 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 534 if (mcopy) { 535 uint32_t mtu; 536#if IPSEC 537 struct secpolicy *sp2; 538 int ipsecerror; 539 size_t ipsechdrsiz; 540#endif 541 542 mtu = rt->rt_ifp->if_mtu; 543#if IPSEC 544 /* 545 * When we do IPsec tunnel ingress, we need to play 546 * with the link value (decrement IPsec header size 547 * from mtu value). The code is much simpler than v4 548 * case, as we have the outgoing interface for 549 * encapsulated packet as "rt->rt_ifp". 550 */ 551 sp2 = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 552 IP_FORWARDING, &ipsecerror); 553 if (sp2) { 554 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 555 IPSEC_DIR_OUTBOUND, NULL); 556 if (ipsechdrsiz < mtu) 557 mtu -= ipsechdrsiz; 558 key_freesp(sp2, KEY_SADB_UNLOCKED); 559 } 560 /* 561 * if mtu becomes less than minimum MTU, 562 * tell minimum MTU (and I'll need to fragment it). 563 */ 564 if (mtu < IPV6_MMTU) 565 mtu = IPV6_MMTU; 566#endif 567 /* Release extra ref */ 568 RT_REMREF_LOCKED(rt); 569 RT_UNLOCK(rt); 570 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 571 } else { 572 /* Release extra ref */ 573 RT_REMREF_LOCKED(rt); 574 RT_UNLOCK(rt); 575 } 576 m_freem(m); 577 return (NULL); 578 } 579 580 if (rt->rt_flags & RTF_GATEWAY) 581 dst = (struct sockaddr_in6 *)(void *)rt->rt_gateway; 582 583 /* 584 * If we are to forward the packet using the same interface 585 * as one we got the packet from, perhaps we should send a redirect 586 * to sender to shortcut a hop. 587 * Only send redirect if source is sending directly to us, 588 * and if packet was not source routed (or has any options). 589 * Also, don't send redirect if forwarding using a route 590 * modified by a redirect. 591 */ 592 if (!proxy && 593 ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 594 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 595 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 596 /* 597 * If the incoming interface is equal to the outgoing 598 * one, and the link attached to the interface is 599 * point-to-point, then it will be highly probable 600 * that a routing loop occurs. Thus, we immediately 601 * drop the packet and send an ICMPv6 error message. 602 * 603 * type/code is based on suggestion by Rich Draves. 604 * not sure if it is the best pick. 605 */ 606 RT_REMREF_LOCKED(rt); /* Release extra ref */ 607 RT_UNLOCK(rt); 608 icmp6_error(mcopy, ICMP6_DST_UNREACH, 609 ICMP6_DST_UNREACH_ADDR, 0); 610 m_freem(m); 611 return (NULL); 612 } 613 type = ND_REDIRECT; 614 } 615 616#if IPFW2 617 /* 618 * Check with the firewall... 619 */ 620 if (ip6_fw_enable && ip6_fw_chk_ptr) { 621 u_short port = 0; 622 ifp = rt->rt_ifp; 623 /* Drop the lock but retain the extra ref */ 624 RT_UNLOCK(rt); 625 /* If ipfw says divert, we have to just drop packet */ 626 if (ip6_fw_chk_ptr(&ip6, ifp, &port, &m)) { 627 m_freem(m); 628 goto freecopy; 629 } 630 if (!m) { 631 goto freecopy; 632 } 633 /* We still have the extra ref on rt */ 634 RT_LOCK(rt); 635 } 636#endif 637 638 /* 639 * Fake scoped addresses. Note that even link-local source or 640 * destinaion can appear, if the originating node just sends the 641 * packet to us (without address resolution for the destination). 642 * Since both icmp6_error and icmp6_redirect_output fill the embedded 643 * link identifiers, we can do this stuff after making a copy for 644 * returning an error. 645 */ 646 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 647 /* 648 * See corresponding comments in ip6_output. 649 * XXX: but is it possible that ip6_forward() sends a packet 650 * to a loopback interface? I don't think so, and thus 651 * I bark here. (jinmei@kame.net) 652 * XXX: it is common to route invalid packets to loopback. 653 * also, the codepath will be visited on use of ::1 in 654 * rthdr. (itojun) 655 */ 656#if 1 657 if (0) 658#else 659 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 660#endif 661 { 662 printf("ip6_forward: outgoing interface is loopback. " 663 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 664 ip6_sprintf(&ip6->ip6_src), 665 ip6_sprintf(&ip6->ip6_dst), 666 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 667 if_name(rt->rt_ifp)); 668 } 669 670 /* we can just use rcvif in forwarding. */ 671 origifp = rcvifp = m->m_pkthdr.rcvif; 672 } else if (nd6_prproxy) { 673 /* 674 * In the prefix proxying case, we need to inform nd6_output() 675 * about the inbound interface, so that any subsequent NS 676 * packets generated by nd6_prproxy_ns_output() will not be 677 * sent back to that same interface. 678 */ 679 origifp = rcvifp = m->m_pkthdr.rcvif; 680 } else { 681 rcvifp = m->m_pkthdr.rcvif; 682 origifp = rt->rt_ifp; 683 } 684 /* 685 * clear embedded scope identifiers if necessary. 686 * in6_clearscope will touch the addresses only when necessary. 687 */ 688 in6_clearscope(&ip6->ip6_src); 689 in6_clearscope(&ip6->ip6_dst); 690 691 ifp = rt->rt_ifp; 692 /* Drop the lock but retain the extra ref */ 693 RT_UNLOCK(rt); 694 695 /* 696 * If this is to be processed locally, let ip6_input have it. 697 */ 698 if (proxy) { 699 VERIFY(m->m_pkthdr.pkt_flags & PKTF_PROXY_DST); 700 /* Release extra ref */ 701 RT_REMREF(rt); 702 if (mcopy != NULL) 703 m_freem(mcopy); 704 return (m); 705 } 706 707#if PF 708 /* Invoke outbound packet filter */ 709 error = pf_af_hook(ifp, NULL, &m, AF_INET6, FALSE, NULL); 710 711 if (error != 0 || m == NULL) { 712 if (m != NULL) { 713 panic("%s: unexpected packet %p\n", __func__, m); 714 /* NOTREACHED */ 715 } 716 /* Already freed by callee */ 717 goto senderr; 718 } 719 ip6 = mtod(m, struct ip6_hdr *); 720#endif /* PF */ 721 722 /* Mark this packet as being forwarded from another interface */ 723 m->m_pkthdr.pkt_flags |= PKTF_FORWARDED; 724 len = m_pktlen(m); 725 726 error = nd6_output(ifp, origifp, m, dst, rt, NULL); 727 if (error) { 728 in6_ifstat_inc(ifp, ifs6_out_discard); 729 ip6stat.ip6s_cantforward++; 730 } else { 731 /* 732 * Increment stats on the source interface; the ones 733 * for destination interface has been taken care of 734 * during output above by virtue of PKTF_FORWARDED. 735 */ 736 rcvifp->if_fpackets++; 737 rcvifp->if_fbytes += len; 738 739 ip6stat.ip6s_forward++; 740 in6_ifstat_inc(ifp, ifs6_out_forward); 741 if (type) 742 ip6stat.ip6s_redirectsent++; 743 else { 744 if (mcopy) { 745 goto freecopy; 746 } 747 } 748 } 749#if PF 750senderr: 751#endif /* PF */ 752 if (mcopy == NULL) { 753 /* Release extra ref */ 754 RT_REMREF(rt); 755 return (NULL); 756 } 757 switch (error) { 758 case 0: 759#if 1 760 if (type == ND_REDIRECT) { 761 icmp6_redirect_output(mcopy, rt); 762 /* Release extra ref */ 763 RT_REMREF(rt); 764 return (NULL); 765 } 766#endif 767 goto freecopy; 768 769 case EMSGSIZE: 770 /* xxx MTU is constant in PPP? */ 771 goto freecopy; 772 773 case ENOBUFS: 774 /* Tell source to slow down like source quench in IP? */ 775 goto freecopy; 776 777 case ENETUNREACH: /* shouldn't happen, checked above */ 778 case EHOSTUNREACH: 779 case ENETDOWN: 780 case EHOSTDOWN: 781 default: 782 type = ICMP6_DST_UNREACH; 783 code = ICMP6_DST_UNREACH_ADDR; 784 break; 785 } 786 icmp6_error(mcopy, type, code, 0); 787 /* Release extra ref */ 788 RT_REMREF(rt); 789 return (NULL); 790 791 freecopy: 792 m_freem(mcopy); 793 /* Release extra ref */ 794 RT_REMREF(rt); 795 return (NULL); 796} 797