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. 202 * Do not forward packets with unspecified source. It was discussed 203 * in July 2000, on ipngwg mailing list. 204 */ 205 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 206 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 207 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 208 ip6stat.ip6s_cantforward++; 209 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 210 if (ip6_log_time + ip6_log_interval < curtime) { 211 ip6_log_time = curtime; 212 log(LOG_DEBUG, 213 "cannot forward " 214 "from %s to %s nxt %d received on %s\n", 215 ip6_sprintf(&ip6->ip6_src), 216 ip6_sprintf(&ip6->ip6_dst), 217 ip6->ip6_nxt, 218 if_name(m->m_pkthdr.rcvif)); 219 } 220 m_freem(m); 221 return (NULL); 222 } 223 224 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 225 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 226 icmp6_error(m, ICMP6_TIME_EXCEEDED, 227 ICMP6_TIME_EXCEED_TRANSIT, 0); 228 return (NULL); 229 } 230 231 /* 232 * See if the destination is a proxied address, and if so pretend 233 * that it's for us. This is mostly to handle NUD probes against 234 * the proxied addresses. We filter for ICMPv6 here and will let 235 * icmp6_input handle the rest. 236 */ 237 if (!srcrt && nd6_prproxy) { 238 VERIFY(!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)); 239 proxy = nd6_prproxy_isours(m, ip6, ip6forward_rt, ifscope); 240 /* 241 * Don't update hop limit while proxying; RFC 4389 4.1. 242 * Also skip IPsec forwarding path processing as this 243 * packet is not to be forwarded. 244 */ 245 if (proxy) 246 goto skip_ipsec; 247 } 248 249 ip6->ip6_hlim -= IPV6_HLIMDEC; 250 251 /* 252 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 253 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 254 * we need to generate an ICMP6 message to the src. 255 * Thanks to M_EXT, in most cases copy will not occur. 256 * 257 * It is important to save it before IPsec processing as IPsec 258 * processing may modify the mbuf. 259 */ 260 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 261 262#if IPSEC 263 if (ipsec_bypass != 0) 264 goto skip_ipsec; 265 /* get a security policy for this packet */ 266 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, 267 &error); 268 if (sp == NULL) { 269 IPSEC_STAT_INCREMENT(ipsec6stat.out_inval); 270 ip6stat.ip6s_cantforward++; 271 if (mcopy) { 272#if 0 273 /* XXX: what icmp ? */ 274#else 275 m_freem(mcopy); 276#endif 277 } 278 m_freem(m); 279 return (NULL); 280 } 281 282 error = 0; 283 284 /* check policy */ 285 switch (sp->policy) { 286 case IPSEC_POLICY_DISCARD: 287 case IPSEC_POLICY_GENERATE: 288 /* 289 * This packet is just discarded. 290 */ 291 IPSEC_STAT_INCREMENT(ipsec6stat.out_polvio); 292 ip6stat.ip6s_cantforward++; 293 key_freesp(sp, KEY_SADB_UNLOCKED); 294 if (mcopy) { 295#if 0 296 /* XXX: what icmp ? */ 297#else 298 m_freem(mcopy); 299#endif 300 } 301 m_freem(m); 302 return (NULL); 303 304 case IPSEC_POLICY_BYPASS: 305 case IPSEC_POLICY_NONE: 306 /* no need to do IPsec. */ 307 key_freesp(sp, KEY_SADB_UNLOCKED); 308 goto skip_ipsec; 309 310 case IPSEC_POLICY_IPSEC: 311 if (sp->req == NULL) { 312 /* XXX should be panic ? */ 313 printf("ip6_forward: No IPsec request specified.\n"); 314 ip6stat.ip6s_cantforward++; 315 key_freesp(sp, KEY_SADB_UNLOCKED); 316 if (mcopy) { 317#if 0 318 /* XXX: what icmp ? */ 319#else 320 m_freem(mcopy); 321#endif 322 } 323 m_freem(m); 324 return (NULL); 325 } 326 /* do IPsec */ 327 break; 328 329 case IPSEC_POLICY_ENTRUST: 330 default: 331 /* should be panic ?? */ 332 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 333 key_freesp(sp, KEY_SADB_UNLOCKED); 334 goto skip_ipsec; 335 } 336 337 { 338 struct ipsec_output_state state; 339 340 /* 341 * All the extension headers will become inaccessible 342 * (since they can be encrypted). 343 * Don't panic, we need no more updates to extension headers 344 * on inner IPv6 packet (since they are now encapsulated). 345 * 346 * IPv6 [ESP|AH] IPv6 [extension headers] payload 347 */ 348 bzero(&state, sizeof(state)); 349 state.m = m; 350 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 351 352 error = ipsec6_output_tunnel(&state, sp, 0); 353 key_freesp(sp, KEY_SADB_UNLOCKED); 354 if (state.tunneled == 4) { 355 ROUTE_RELEASE(&state.ro); 356 return (NULL); /* packet is gone - sent over IPv4 */ 357 } 358 359 m = state.m; 360 ROUTE_RELEASE(&state.ro); 361 362 if (error) { 363 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 364 switch (error) { 365 case EHOSTUNREACH: 366 case ENETUNREACH: 367 case EMSGSIZE: 368 case ENOBUFS: 369 case ENOMEM: 370 break; 371 default: 372 printf("ip6_output (ipsec): error code %d\n", error); 373 /* fall through */ 374 case ENOENT: 375 /* don't show these error codes to the user */ 376 break; 377 } 378 ip6stat.ip6s_cantforward++; 379 if (mcopy) { 380#if 0 381 /* XXX: what icmp ? */ 382#else 383 m_freem(mcopy); 384#endif 385 } 386 m_freem(m); 387 return (NULL); 388 } 389 } 390#endif /* IPSEC */ 391 skip_ipsec: 392 393 dst = (struct sockaddr_in6 *)&ip6forward_rt->ro_dst; 394 if ((rt = ip6forward_rt->ro_rt) != NULL) { 395 RT_LOCK(rt); 396 /* Take an extra ref for ourselves */ 397 RT_ADDREF_LOCKED(rt); 398 } 399 400 VERIFY(rt == NULL || rt == ip6forward_rt->ro_rt); 401 if (!srcrt) { 402 /* 403 * ip6forward_rt->ro_dst.sin6_addr is equal to ip6->ip6_dst 404 */ 405 if (ROUTE_UNUSABLE(ip6forward_rt)) { 406 if (rt != NULL) { 407 /* Release extra ref */ 408 RT_REMREF_LOCKED(rt); 409 RT_UNLOCK(rt); 410 } 411 ROUTE_RELEASE(ip6forward_rt); 412 413 /* this probably fails but give it a try again */ 414 rtalloc_scoped_ign((struct route *)ip6forward_rt, 415 RTF_PRCLONING, ifscope); 416 if ((rt = ip6forward_rt->ro_rt) != NULL) { 417 RT_LOCK(rt); 418 /* Take an extra ref for ourselves */ 419 RT_ADDREF_LOCKED(rt); 420 } 421 } 422 423 if (rt == NULL) { 424 ip6stat.ip6s_noroute++; 425 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 426 if (mcopy) 427 icmp6_error(mcopy, ICMP6_DST_UNREACH, 428 ICMP6_DST_UNREACH_NOROUTE, 0); 429 m_freem(m); 430 return (NULL); 431 } 432 RT_LOCK_ASSERT_HELD(rt); 433 } else if (ROUTE_UNUSABLE(ip6forward_rt) || 434 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 435 if (rt != NULL) { 436 /* Release extra ref */ 437 RT_REMREF_LOCKED(rt); 438 RT_UNLOCK(rt); 439 } 440 ROUTE_RELEASE(ip6forward_rt); 441 442 bzero(dst, sizeof(*dst)); 443 dst->sin6_len = sizeof(struct sockaddr_in6); 444 dst->sin6_family = AF_INET6; 445 dst->sin6_addr = ip6->ip6_dst; 446 447 rtalloc_scoped_ign((struct route *)ip6forward_rt, 448 RTF_PRCLONING, ifscope); 449 if ((rt = ip6forward_rt->ro_rt) == NULL) { 450 ip6stat.ip6s_noroute++; 451 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 452 if (mcopy) 453 icmp6_error(mcopy, ICMP6_DST_UNREACH, 454 ICMP6_DST_UNREACH_NOROUTE, 0); 455 m_freem(m); 456 return (NULL); 457 } 458 RT_LOCK(rt); 459 /* Take an extra ref for ourselves */ 460 RT_ADDREF_LOCKED(rt); 461 } 462 463 /* 464 * Source scope check: if a packet can't be delivered to its 465 * destination for the reason that the destination is beyond the scope 466 * of the source address, discard the packet and return an icmp6 467 * destination unreachable error with Code 2 (beyond scope of source 468 * address) unless we are proxying (source address is link local 469 * for NUDs.) We use a local copy of ip6_src, since in6_setscope() 470 * will possibly modify its first argument. 471 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] 472 */ 473 src_in6 = ip6->ip6_src; 474 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 475 /* XXX: this should not happen */ 476 ip6stat.ip6s_cantforward++; 477 ip6stat.ip6s_badscope++; 478 m_freem(m); 479 return (NULL); 480 } 481 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 482 ip6stat.ip6s_cantforward++; 483 ip6stat.ip6s_badscope++; 484 m_freem(m); 485 return (NULL); 486 } 487 488 if (inzone != outzone && !proxy) { 489 ip6stat.ip6s_cantforward++; 490 ip6stat.ip6s_badscope++; 491 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 492 493 if (ip6_log_time + ip6_log_interval < curtime) { 494 ip6_log_time = curtime; 495 log(LOG_DEBUG, 496 "cannot forward " 497 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 498 ip6_sprintf(&ip6->ip6_src), 499 ip6_sprintf(&ip6->ip6_dst), 500 ip6->ip6_nxt, 501 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 502 } 503 /* Release extra ref */ 504 RT_REMREF_LOCKED(rt); 505 RT_UNLOCK(rt); 506 if (mcopy) { 507 icmp6_error(mcopy, ICMP6_DST_UNREACH, 508 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 509 } 510 m_freem(m); 511 return (NULL); 512 } 513 514 /* 515 * Destination scope check: if a packet is going to break the scope 516 * zone of packet's destination address, discard it. This case should 517 * usually be prevented by appropriately-configured routing table, but 518 * we need an explicit check because we may mistakenly forward the 519 * packet to a different zone by (e.g.) a default route. 520 */ 521 dst_in6 = ip6->ip6_dst; 522 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 523 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 524 inzone != outzone) { 525 ip6stat.ip6s_cantforward++; 526 ip6stat.ip6s_badscope++; 527 m_freem(m); 528 return (NULL); 529 } 530 531 if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { 532 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 533 if (mcopy) { 534 uint32_t mtu; 535#if IPSEC 536 struct secpolicy *sp2; 537 int ipsecerror; 538 size_t ipsechdrsiz; 539#endif 540 541 mtu = rt->rt_ifp->if_mtu; 542#if IPSEC 543 /* 544 * When we do IPsec tunnel ingress, we need to play 545 * with the link value (decrement IPsec header size 546 * from mtu value). The code is much simpler than v4 547 * case, as we have the outgoing interface for 548 * encapsulated packet as "rt->rt_ifp". 549 */ 550 sp2 = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 551 IP_FORWARDING, &ipsecerror); 552 if (sp2) { 553 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 554 IPSEC_DIR_OUTBOUND, NULL); 555 if (ipsechdrsiz < mtu) 556 mtu -= ipsechdrsiz; 557 key_freesp(sp2, KEY_SADB_UNLOCKED); 558 } 559 /* 560 * if mtu becomes less than minimum MTU, 561 * tell minimum MTU (and I'll need to fragment it). 562 */ 563 if (mtu < IPV6_MMTU) 564 mtu = IPV6_MMTU; 565#endif 566 /* Release extra ref */ 567 RT_REMREF_LOCKED(rt); 568 RT_UNLOCK(rt); 569 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 570 } else { 571 /* Release extra ref */ 572 RT_REMREF_LOCKED(rt); 573 RT_UNLOCK(rt); 574 } 575 m_freem(m); 576 return (NULL); 577 } 578 579 if (rt->rt_flags & RTF_GATEWAY) 580 dst = (struct sockaddr_in6 *)(void *)rt->rt_gateway; 581 582 /* 583 * If we are to forward the packet using the same interface 584 * as one we got the packet from, perhaps we should send a redirect 585 * to sender to shortcut a hop. 586 * Only send redirect if source is sending directly to us, 587 * and if packet was not source routed (or has any options). 588 * Also, don't send redirect if forwarding using a route 589 * modified by a redirect. 590 */ 591 if (!proxy && 592 ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 593 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 594 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 595 /* 596 * If the incoming interface is equal to the outgoing 597 * one, and the link attached to the interface is 598 * point-to-point, then it will be highly probable 599 * that a routing loop occurs. Thus, we immediately 600 * drop the packet and send an ICMPv6 error message. 601 * 602 * type/code is based on suggestion by Rich Draves. 603 * not sure if it is the best pick. 604 */ 605 RT_REMREF_LOCKED(rt); /* Release extra ref */ 606 RT_UNLOCK(rt); 607 icmp6_error(mcopy, ICMP6_DST_UNREACH, 608 ICMP6_DST_UNREACH_ADDR, 0); 609 m_freem(m); 610 return (NULL); 611 } 612 type = ND_REDIRECT; 613 } 614 615#if IPFW2 616 /* 617 * Check with the firewall... 618 */ 619 if (ip6_fw_enable && ip6_fw_chk_ptr) { 620 u_short port = 0; 621 ifp = rt->rt_ifp; 622 /* Drop the lock but retain the extra ref */ 623 RT_UNLOCK(rt); 624 /* If ipfw says divert, we have to just drop packet */ 625 if (ip6_fw_chk_ptr(&ip6, ifp, &port, &m)) { 626 m_freem(m); 627 goto freecopy; 628 } 629 if (!m) { 630 goto freecopy; 631 } 632 /* We still have the extra ref on rt */ 633 RT_LOCK(rt); 634 } 635#endif 636 637 /* 638 * Fake scoped addresses. Note that even link-local source or 639 * destinaion can appear, if the originating node just sends the 640 * packet to us (without address resolution for the destination). 641 * Since both icmp6_error and icmp6_redirect_output fill the embedded 642 * link identifiers, we can do this stuff after making a copy for 643 * returning an error. 644 */ 645 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 646 /* 647 * See corresponding comments in ip6_output. 648 * XXX: but is it possible that ip6_forward() sends a packet 649 * to a loopback interface? I don't think so, and thus 650 * I bark here. (jinmei@kame.net) 651 * XXX: it is common to route invalid packets to loopback. 652 * also, the codepath will be visited on use of ::1 in 653 * rthdr. (itojun) 654 */ 655#if 1 656 if ((0)) 657#else 658 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 659#endif 660 { 661 printf("ip6_forward: outgoing interface is loopback. " 662 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 663 ip6_sprintf(&ip6->ip6_src), 664 ip6_sprintf(&ip6->ip6_dst), 665 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 666 if_name(rt->rt_ifp)); 667 } 668 669 /* we can just use rcvif in forwarding. */ 670 origifp = rcvifp = m->m_pkthdr.rcvif; 671 } else if (nd6_prproxy) { 672 /* 673 * In the prefix proxying case, we need to inform nd6_output() 674 * about the inbound interface, so that any subsequent NS 675 * packets generated by nd6_prproxy_ns_output() will not be 676 * sent back to that same interface. 677 */ 678 origifp = rcvifp = m->m_pkthdr.rcvif; 679 } else { 680 rcvifp = m->m_pkthdr.rcvif; 681 origifp = rt->rt_ifp; 682 } 683 /* 684 * clear embedded scope identifiers if necessary. 685 * in6_clearscope will touch the addresses only when necessary. 686 */ 687 in6_clearscope(&ip6->ip6_src); 688 in6_clearscope(&ip6->ip6_dst); 689 690 ifp = rt->rt_ifp; 691 /* Drop the lock but retain the extra ref */ 692 RT_UNLOCK(rt); 693 694 /* 695 * If this is to be processed locally, let ip6_input have it. 696 */ 697 if (proxy) { 698 VERIFY(m->m_pkthdr.pkt_flags & PKTF_PROXY_DST); 699 /* Release extra ref */ 700 RT_REMREF(rt); 701 if (mcopy != NULL) 702 m_freem(mcopy); 703 return (m); 704 } 705 706#if PF 707 /* Invoke outbound packet filter */ 708 error = pf_af_hook(ifp, NULL, &m, AF_INET6, FALSE, NULL); 709 710 if (error != 0 || m == NULL) { 711 if (m != NULL) { 712 panic("%s: unexpected packet %p\n", __func__, m); 713 /* NOTREACHED */ 714 } 715 /* Already freed by callee */ 716 goto senderr; 717 } 718 ip6 = mtod(m, struct ip6_hdr *); 719#endif /* PF */ 720 721 /* Mark this packet as being forwarded from another interface */ 722 m->m_pkthdr.pkt_flags |= PKTF_FORWARDED; 723 len = m_pktlen(m); 724 725 error = nd6_output(ifp, origifp, m, dst, rt, NULL); 726 if (error) { 727 in6_ifstat_inc(ifp, ifs6_out_discard); 728 ip6stat.ip6s_cantforward++; 729 } else { 730 /* 731 * Increment stats on the source interface; the ones 732 * for destination interface has been taken care of 733 * during output above by virtue of PKTF_FORWARDED. 734 */ 735 rcvifp->if_fpackets++; 736 rcvifp->if_fbytes += len; 737 738 ip6stat.ip6s_forward++; 739 in6_ifstat_inc(ifp, ifs6_out_forward); 740 if (type) 741 ip6stat.ip6s_redirectsent++; 742 else { 743 if (mcopy) { 744 goto freecopy; 745 } 746 } 747 } 748#if PF 749senderr: 750#endif /* PF */ 751 if (mcopy == NULL) { 752 /* Release extra ref */ 753 RT_REMREF(rt); 754 return (NULL); 755 } 756 switch (error) { 757 case 0: 758#if 1 759 if (type == ND_REDIRECT) { 760 icmp6_redirect_output(mcopy, rt); 761 /* Release extra ref */ 762 RT_REMREF(rt); 763 return (NULL); 764 } 765#endif 766 goto freecopy; 767 768 case EMSGSIZE: 769 /* xxx MTU is constant in PPP? */ 770 goto freecopy; 771 772 case ENOBUFS: 773 /* Tell source to slow down like source quench in IP? */ 774 goto freecopy; 775 776 case ENETUNREACH: /* shouldn't happen, checked above */ 777 case EHOSTUNREACH: 778 case ENETDOWN: 779 case EHOSTDOWN: 780 default: 781 type = ICMP6_DST_UNREACH; 782 code = ICMP6_DST_UNREACH_ADDR; 783 break; 784 } 785 icmp6_error(mcopy, type, code, 0); 786 /* Release extra ref */ 787 RT_REMREF(rt); 788 return (NULL); 789 790 freecopy: 791 m_freem(mcopy); 792 /* Release extra ref */ 793 RT_REMREF(rt); 794 return (NULL); 795} 796