1/*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $
30 */
31
32#include <sys/cdefs.h>
| 1/*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $
30 */
31
32#include <sys/cdefs.h>
|
81/*
82 * Forward a packet. If some error occurs return the sender
83 * an icmp packet. Note we can't always generate a meaningful
84 * icmp message because icmp doesn't have a large enough repertoire
85 * of codes and types.
86 *
87 * If not forwarding, just drop the packet. This could be confusing
88 * if ipforwarding was zero but some routing protocol was advancing
89 * us as a gateway to somewhere. However, we must let the routing
90 * protocol deal with that.
91 *
92 */
93void
94ip6_forward(struct mbuf *m, int srcrt)
95{
96 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
97 struct sockaddr_in6 *dst = NULL;
98 struct rtentry *rt = NULL;
99 struct route_in6 rin6;
100 int error, type = 0, code = 0;
101 struct mbuf *mcopy = NULL;
102 struct ifnet *origifp; /* maybe unnecessary */
103 u_int32_t inzone, outzone;
104 struct in6_addr src_in6, dst_in6, odst;
105#ifdef IPSEC
106 struct secpolicy *sp = NULL;
107#endif
108#ifdef SCTP
109 int sw_csum;
110#endif
111 struct m_tag *fwd_tag;
112 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
113
114#ifdef IPSEC
115 /*
116 * Check AH/ESP integrity.
117 */
118 /*
119 * Don't increment ip6s_cantforward because this is the check
120 * before forwarding packet actually.
121 */
122 if (ipsec6_in_reject(m, NULL)) {
123 IPSEC6STAT_INC(ips_in_polvio);
124 m_freem(m);
125 return;
126 }
127#endif /* IPSEC */
128
129 /*
130 * Do not forward packets to multicast destination (should be handled
131 * by ip6_mforward().
132 * Do not forward packets with unspecified source. It was discussed
133 * in July 2000, on the ipngwg mailing list.
134 */
135 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
136 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
137 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
138 IP6STAT_INC(ip6s_cantforward);
139 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
140 if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
141 V_ip6_log_time = time_uptime;
142 log(LOG_DEBUG,
143 "cannot forward "
144 "from %s to %s nxt %d received on %s\n",
145 ip6_sprintf(ip6bufs, &ip6->ip6_src),
146 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
147 ip6->ip6_nxt,
148 if_name(m->m_pkthdr.rcvif));
149 }
150 m_freem(m);
151 return;
152 }
153
154#ifdef IPSTEALTH
155 if (!V_ip6stealth) {
156#endif
157 if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
158 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
159 icmp6_error(m, ICMP6_TIME_EXCEEDED,
160 ICMP6_TIME_EXCEED_TRANSIT, 0);
161 return;
162 }
163 ip6->ip6_hlim -= IPV6_HLIMDEC;
164
165#ifdef IPSTEALTH
166 }
167#endif
168
169 /*
170 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
171 * size of IPv6 + ICMPv6 headers) bytes of the packet in case
172 * we need to generate an ICMP6 message to the src.
173 * Thanks to M_EXT, in most cases copy will not occur.
174 *
175 * It is important to save it before IPsec processing as IPsec
176 * processing may modify the mbuf.
177 */
178 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
179
180#ifdef IPSEC
181 /* get a security policy for this packet */
182 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
183 IP_FORWARDING, &error);
184 if (sp == NULL) {
185 IPSEC6STAT_INC(ips_out_inval);
186 IP6STAT_INC(ip6s_cantforward);
187 if (mcopy) {
188#if 0
189 /* XXX: what icmp ? */
190#else
191 m_freem(mcopy);
192#endif
193 }
194 m_freem(m);
195 return;
196 }
197
198 error = 0;
199
200 /* check policy */
201 switch (sp->policy) {
202 case IPSEC_POLICY_DISCARD:
203 /*
204 * This packet is just discarded.
205 */
206 IPSEC6STAT_INC(ips_out_polvio);
207 IP6STAT_INC(ip6s_cantforward);
208 KEY_FREESP(&sp);
209 if (mcopy) {
210#if 0
211 /* XXX: what icmp ? */
212#else
213 m_freem(mcopy);
214#endif
215 }
216 m_freem(m);
217 return;
218
219 case IPSEC_POLICY_BYPASS:
220 case IPSEC_POLICY_NONE:
221 /* no need to do IPsec. */
222 KEY_FREESP(&sp);
223 goto skip_ipsec;
224
225 case IPSEC_POLICY_IPSEC:
226 if (sp->req == NULL) {
227 /* XXX should be panic ? */
228 printf("ip6_forward: No IPsec request specified.\n");
229 IP6STAT_INC(ip6s_cantforward);
230 KEY_FREESP(&sp);
231 if (mcopy) {
232#if 0
233 /* XXX: what icmp ? */
234#else
235 m_freem(mcopy);
236#endif
237 }
238 m_freem(m);
239 return;
240 }
241 /* do IPsec */
242 break;
243
244 case IPSEC_POLICY_ENTRUST:
245 default:
246 /* should be panic ?? */
247 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
248 KEY_FREESP(&sp);
249 goto skip_ipsec;
250 }
251
252 {
253 struct ipsecrequest *isr = NULL;
254
255 /*
256 * when the kernel forwards a packet, it is not proper to apply
257 * IPsec transport mode to the packet is not proper. this check
258 * avoid from this.
259 * at present, if there is even a transport mode SA request in the
260 * security policy, the kernel does not apply IPsec to the packet.
261 * this check is not enough because the following case is valid.
262 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
263 */
264 for (isr = sp->req; isr; isr = isr->next) {
265 if (isr->saidx.mode == IPSEC_MODE_ANY)
266 goto doipsectunnel;
267 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
268 goto doipsectunnel;
269 }
270
271 /*
272 * if there's no need for tunnel mode IPsec, skip.
273 */
274 if (!isr)
275 goto skip_ipsec;
276
277 doipsectunnel:
278 /*
279 * All the extension headers will become inaccessible
280 * (since they can be encrypted).
281 * Don't panic, we need no more updates to extension headers
282 * on inner IPv6 packet (since they are now encapsulated).
283 *
284 * IPv6 [ESP|AH] IPv6 [extension headers] payload
285 */
286
287 /*
288 * If we need to encapsulate the packet, do it here
289 * ipsec6_proces_packet will send the packet using ip6_output
290 */
291 error = ipsec6_process_packet(m, sp->req);
292
293 KEY_FREESP(&sp);
294
295 if (error == EJUSTRETURN) {
296 /*
297 * We had a SP with a level of 'use' and no SA. We
298 * will just continue to process the packet without
299 * IPsec processing.
300 */
301 error = 0;
302 goto skip_ipsec;
303 }
304
305 if (error) {
306 /* mbuf is already reclaimed in ipsec6_process_packet. */
307 switch (error) {
308 case EHOSTUNREACH:
309 case ENETUNREACH:
310 case EMSGSIZE:
311 case ENOBUFS:
312 case ENOMEM:
313 break;
314 default:
315 printf("ip6_output (ipsec): error code %d\n", error);
316 /* FALLTHROUGH */
317 case ENOENT:
318 /* don't show these error codes to the user */
319 break;
320 }
321 IP6STAT_INC(ip6s_cantforward);
322 if (mcopy) {
323#if 0
324 /* XXX: what icmp ? */
325#else
326 m_freem(mcopy);
327#endif
328 }
329 return;
330 } else {
331 /*
332 * In the FAST IPSec case we have already
333 * re-injected the packet and it has been freed
334 * by the ipsec_done() function. So, just clean
335 * up after ourselves.
336 */
337 m = NULL;
338 goto freecopy;
339 }
340 }
341skip_ipsec:
342#endif
343again:
344 bzero(&rin6, sizeof(struct route_in6));
345 dst = (struct sockaddr_in6 *)&rin6.ro_dst;
346 dst->sin6_len = sizeof(struct sockaddr_in6);
347 dst->sin6_family = AF_INET6;
348 dst->sin6_addr = ip6->ip6_dst;
349again2:
350 rin6.ro_rt = in6_rtalloc1((struct sockaddr *)dst, 0, 0, M_GETFIB(m));
351 if (rin6.ro_rt != NULL)
352 RT_UNLOCK(rin6.ro_rt);
353 else {
354 IP6STAT_INC(ip6s_noroute);
355 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
356 if (mcopy) {
357 icmp6_error(mcopy, ICMP6_DST_UNREACH,
358 ICMP6_DST_UNREACH_NOROUTE, 0);
359 }
360 goto bad;
361 }
362 rt = rin6.ro_rt;
363
364 /*
365 * Source scope check: if a packet can't be delivered to its
366 * destination for the reason that the destination is beyond the scope
367 * of the source address, discard the packet and return an icmp6
368 * destination unreachable error with Code 2 (beyond scope of source
369 * address). We use a local copy of ip6_src, since in6_setscope()
370 * will possibly modify its first argument.
371 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
372 */
373 src_in6 = ip6->ip6_src;
374 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
375 /* XXX: this should not happen */
376 IP6STAT_INC(ip6s_cantforward);
377 IP6STAT_INC(ip6s_badscope);
378 goto bad;
379 }
380 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
381 IP6STAT_INC(ip6s_cantforward);
382 IP6STAT_INC(ip6s_badscope);
383 goto bad;
384 }
385 if (inzone != outzone) {
386 IP6STAT_INC(ip6s_cantforward);
387 IP6STAT_INC(ip6s_badscope);
388 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
389
390 if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
391 V_ip6_log_time = time_uptime;
392 log(LOG_DEBUG,
393 "cannot forward "
394 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
395 ip6_sprintf(ip6bufs, &ip6->ip6_src),
396 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
397 ip6->ip6_nxt,
398 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
399 }
400 if (mcopy)
401 icmp6_error(mcopy, ICMP6_DST_UNREACH,
402 ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
403 goto bad;
404 }
405
406 /*
407 * Destination scope check: if a packet is going to break the scope
408 * zone of packet's destination address, discard it. This case should
409 * usually be prevented by appropriately-configured routing table, but
410 * we need an explicit check because we may mistakenly forward the
411 * packet to a different zone by (e.g.) a default route.
412 */
413 dst_in6 = ip6->ip6_dst;
414 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
415 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
416 inzone != outzone) {
417 IP6STAT_INC(ip6s_cantforward);
418 IP6STAT_INC(ip6s_badscope);
419 goto bad;
420 }
421
422 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
423 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
424 if (mcopy) {
425 u_long mtu;
426#ifdef IPSEC
427 struct secpolicy *sp;
428 int ipsecerror;
429 size_t ipsechdrsiz;
430#endif /* IPSEC */
431
432 mtu = IN6_LINKMTU(rt->rt_ifp);
433#ifdef IPSEC
434 /*
435 * When we do IPsec tunnel ingress, we need to play
436 * with the link value (decrement IPsec header size
437 * from mtu value). The code is much simpler than v4
438 * case, as we have the outgoing interface for
439 * encapsulated packet as "rt->rt_ifp".
440 */
441 sp = ipsec_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
442 IP_FORWARDING, &ipsecerror);
443 if (sp) {
444 ipsechdrsiz = ipsec_hdrsiz(mcopy,
445 IPSEC_DIR_OUTBOUND, NULL);
446 if (ipsechdrsiz < mtu)
447 mtu -= ipsechdrsiz;
448 }
449
450 /*
451 * if mtu becomes less than minimum MTU,
452 * tell minimum MTU (and I'll need to fragment it).
453 */
454 if (mtu < IPV6_MMTU)
455 mtu = IPV6_MMTU;
456#endif /* IPSEC */
457 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
458 }
459 goto bad;
460 }
461
462 if (rt->rt_flags & RTF_GATEWAY)
463 dst = (struct sockaddr_in6 *)rt->rt_gateway;
464
465 /*
466 * If we are to forward the packet using the same interface
467 * as one we got the packet from, perhaps we should send a redirect
468 * to sender to shortcut a hop.
469 * Only send redirect if source is sending directly to us,
470 * and if packet was not source routed (or has any options).
471 * Also, don't send redirect if forwarding using a route
472 * modified by a redirect.
473 */
474 if (V_ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
475 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
476 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
477 /*
478 * If the incoming interface is equal to the outgoing
479 * one, and the link attached to the interface is
480 * point-to-point, then it will be highly probable
481 * that a routing loop occurs. Thus, we immediately
482 * drop the packet and send an ICMPv6 error message.
483 *
484 * type/code is based on suggestion by Rich Draves.
485 * not sure if it is the best pick.
486 */
487 icmp6_error(mcopy, ICMP6_DST_UNREACH,
488 ICMP6_DST_UNREACH_ADDR, 0);
489 goto bad;
490 }
491 type = ND_REDIRECT;
492 }
493
494 /*
495 * Fake scoped addresses. Note that even link-local source or
496 * destinaion can appear, if the originating node just sends the
497 * packet to us (without address resolution for the destination).
498 * Since both icmp6_error and icmp6_redirect_output fill the embedded
499 * link identifiers, we can do this stuff after making a copy for
500 * returning an error.
501 */
502 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
503 /*
504 * See corresponding comments in ip6_output.
505 * XXX: but is it possible that ip6_forward() sends a packet
506 * to a loopback interface? I don't think so, and thus
507 * I bark here. (jinmei@kame.net)
508 * XXX: it is common to route invalid packets to loopback.
509 * also, the codepath will be visited on use of ::1 in
510 * rthdr. (itojun)
511 */
512#if 1
513 if (0)
514#else
515 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
516#endif
517 {
518 printf("ip6_forward: outgoing interface is loopback. "
519 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
520 ip6_sprintf(ip6bufs, &ip6->ip6_src),
521 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
522 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
523 if_name(rt->rt_ifp));
524 }
525
526 /* we can just use rcvif in forwarding. */
527 origifp = m->m_pkthdr.rcvif;
528 }
529 else
530 origifp = rt->rt_ifp;
531 /*
532 * clear embedded scope identifiers if necessary.
533 * in6_clearscope will touch the addresses only when necessary.
534 */
535 in6_clearscope(&ip6->ip6_src);
536 in6_clearscope(&ip6->ip6_dst);
537
538 /* Jump over all PFIL processing if hooks are not active. */
539 if (!PFIL_HOOKED(&V_inet6_pfil_hook))
540 goto pass;
541
542 odst = ip6->ip6_dst;
543 /* Run through list of hooks for output packets. */
544 error = pfil_run_hooks(&V_inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL);
545 if (error != 0 || m == NULL)
546 goto freecopy; /* consumed by filter */
547 ip6 = mtod(m, struct ip6_hdr *);
548
549 /* See if destination IP address was changed by packet filter. */
550 if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
551 m->m_flags |= M_SKIP_FIREWALL;
552 /* If destination is now ourself drop to ip6_input(). */
553 if (in6_localip(&ip6->ip6_dst)) {
554 m->m_flags |= M_FASTFWD_OURS;
555 if (m->m_pkthdr.rcvif == NULL)
556 m->m_pkthdr.rcvif = V_loif;
557 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
558 m->m_pkthdr.csum_flags |=
559 CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
560 m->m_pkthdr.csum_data = 0xffff;
561 }
562#ifdef SCTP
563 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
564 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
565#endif
566 error = netisr_queue(NETISR_IPV6, m);
567 goto out;
568 } else
569 goto again; /* Redo the routing table lookup. */
570 }
571
572 /* See if local, if yes, send it to netisr. */
573 if (m->m_flags & M_FASTFWD_OURS) {
574 if (m->m_pkthdr.rcvif == NULL)
575 m->m_pkthdr.rcvif = V_loif;
576 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
577 m->m_pkthdr.csum_flags |=
578 CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
579 m->m_pkthdr.csum_data = 0xffff;
580 }
581#ifdef SCTP
582 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
583 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
584#endif
585 error = netisr_queue(NETISR_IPV6, m);
586 goto out;
587 }
588 /* Or forward to some other address? */
589 if ((m->m_flags & M_IP6_NEXTHOP) &&
590 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
591 dst = (struct sockaddr_in6 *)&rin6.ro_dst;
592 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in6));
593 m->m_flags |= M_SKIP_FIREWALL;
594 m->m_flags &= ~M_IP6_NEXTHOP;
595 m_tag_delete(m, fwd_tag);
596 goto again2;
597 }
598
599pass:
600 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
601 if (error) {
602 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
603 IP6STAT_INC(ip6s_cantforward);
604 } else {
605 IP6STAT_INC(ip6s_forward);
606 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
607 if (type)
608 IP6STAT_INC(ip6s_redirectsent);
609 else {
610 if (mcopy)
611 goto freecopy;
612 }
613 }
614
615 if (mcopy == NULL)
616 goto out;
617 switch (error) {
618 case 0:
619 if (type == ND_REDIRECT) {
620 icmp6_redirect_output(mcopy, rt);
621 goto out;
622 }
623 goto freecopy;
624
625 case EMSGSIZE:
626 /* xxx MTU is constant in PPP? */
627 goto freecopy;
628
629 case ENOBUFS:
630 /* Tell source to slow down like source quench in IP? */
631 goto freecopy;
632
633 case ENETUNREACH: /* shouldn't happen, checked above */
634 case EHOSTUNREACH:
635 case ENETDOWN:
636 case EHOSTDOWN:
637 default:
638 type = ICMP6_DST_UNREACH;
639 code = ICMP6_DST_UNREACH_ADDR;
640 break;
641 }
642 icmp6_error(mcopy, type, code, 0);
643 goto out;
644
645 freecopy:
646 m_freem(mcopy);
647 goto out;
648bad:
649 m_freem(m);
650out:
651 if (rt != NULL)
652 RTFREE(rt);
653}
| 79/*
80 * Forward a packet. If some error occurs return the sender
81 * an icmp packet. Note we can't always generate a meaningful
82 * icmp message because icmp doesn't have a large enough repertoire
83 * of codes and types.
84 *
85 * If not forwarding, just drop the packet. This could be confusing
86 * if ipforwarding was zero but some routing protocol was advancing
87 * us as a gateway to somewhere. However, we must let the routing
88 * protocol deal with that.
89 *
90 */
91void
92ip6_forward(struct mbuf *m, int srcrt)
93{
94 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
95 struct sockaddr_in6 *dst = NULL;
96 struct rtentry *rt = NULL;
97 struct route_in6 rin6;
98 int error, type = 0, code = 0;
99 struct mbuf *mcopy = NULL;
100 struct ifnet *origifp; /* maybe unnecessary */
101 u_int32_t inzone, outzone;
102 struct in6_addr src_in6, dst_in6, odst;
103#ifdef IPSEC
104 struct secpolicy *sp = NULL;
105#endif
106#ifdef SCTP
107 int sw_csum;
108#endif
109 struct m_tag *fwd_tag;
110 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
111
112#ifdef IPSEC
113 /*
114 * Check AH/ESP integrity.
115 */
116 /*
117 * Don't increment ip6s_cantforward because this is the check
118 * before forwarding packet actually.
119 */
120 if (ipsec6_in_reject(m, NULL)) {
121 IPSEC6STAT_INC(ips_in_polvio);
122 m_freem(m);
123 return;
124 }
125#endif /* IPSEC */
126
127 /*
128 * Do not forward packets to multicast destination (should be handled
129 * by ip6_mforward().
130 * Do not forward packets with unspecified source. It was discussed
131 * in July 2000, on the ipngwg mailing list.
132 */
133 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
134 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
135 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
136 IP6STAT_INC(ip6s_cantforward);
137 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
138 if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
139 V_ip6_log_time = time_uptime;
140 log(LOG_DEBUG,
141 "cannot forward "
142 "from %s to %s nxt %d received on %s\n",
143 ip6_sprintf(ip6bufs, &ip6->ip6_src),
144 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
145 ip6->ip6_nxt,
146 if_name(m->m_pkthdr.rcvif));
147 }
148 m_freem(m);
149 return;
150 }
151
152#ifdef IPSTEALTH
153 if (!V_ip6stealth) {
154#endif
155 if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
156 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
157 icmp6_error(m, ICMP6_TIME_EXCEEDED,
158 ICMP6_TIME_EXCEED_TRANSIT, 0);
159 return;
160 }
161 ip6->ip6_hlim -= IPV6_HLIMDEC;
162
163#ifdef IPSTEALTH
164 }
165#endif
166
167 /*
168 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
169 * size of IPv6 + ICMPv6 headers) bytes of the packet in case
170 * we need to generate an ICMP6 message to the src.
171 * Thanks to M_EXT, in most cases copy will not occur.
172 *
173 * It is important to save it before IPsec processing as IPsec
174 * processing may modify the mbuf.
175 */
176 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
177
178#ifdef IPSEC
179 /* get a security policy for this packet */
180 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
181 IP_FORWARDING, &error);
182 if (sp == NULL) {
183 IPSEC6STAT_INC(ips_out_inval);
184 IP6STAT_INC(ip6s_cantforward);
185 if (mcopy) {
186#if 0
187 /* XXX: what icmp ? */
188#else
189 m_freem(mcopy);
190#endif
191 }
192 m_freem(m);
193 return;
194 }
195
196 error = 0;
197
198 /* check policy */
199 switch (sp->policy) {
200 case IPSEC_POLICY_DISCARD:
201 /*
202 * This packet is just discarded.
203 */
204 IPSEC6STAT_INC(ips_out_polvio);
205 IP6STAT_INC(ip6s_cantforward);
206 KEY_FREESP(&sp);
207 if (mcopy) {
208#if 0
209 /* XXX: what icmp ? */
210#else
211 m_freem(mcopy);
212#endif
213 }
214 m_freem(m);
215 return;
216
217 case IPSEC_POLICY_BYPASS:
218 case IPSEC_POLICY_NONE:
219 /* no need to do IPsec. */
220 KEY_FREESP(&sp);
221 goto skip_ipsec;
222
223 case IPSEC_POLICY_IPSEC:
224 if (sp->req == NULL) {
225 /* XXX should be panic ? */
226 printf("ip6_forward: No IPsec request specified.\n");
227 IP6STAT_INC(ip6s_cantforward);
228 KEY_FREESP(&sp);
229 if (mcopy) {
230#if 0
231 /* XXX: what icmp ? */
232#else
233 m_freem(mcopy);
234#endif
235 }
236 m_freem(m);
237 return;
238 }
239 /* do IPsec */
240 break;
241
242 case IPSEC_POLICY_ENTRUST:
243 default:
244 /* should be panic ?? */
245 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
246 KEY_FREESP(&sp);
247 goto skip_ipsec;
248 }
249
250 {
251 struct ipsecrequest *isr = NULL;
252
253 /*
254 * when the kernel forwards a packet, it is not proper to apply
255 * IPsec transport mode to the packet is not proper. this check
256 * avoid from this.
257 * at present, if there is even a transport mode SA request in the
258 * security policy, the kernel does not apply IPsec to the packet.
259 * this check is not enough because the following case is valid.
260 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
261 */
262 for (isr = sp->req; isr; isr = isr->next) {
263 if (isr->saidx.mode == IPSEC_MODE_ANY)
264 goto doipsectunnel;
265 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
266 goto doipsectunnel;
267 }
268
269 /*
270 * if there's no need for tunnel mode IPsec, skip.
271 */
272 if (!isr)
273 goto skip_ipsec;
274
275 doipsectunnel:
276 /*
277 * All the extension headers will become inaccessible
278 * (since they can be encrypted).
279 * Don't panic, we need no more updates to extension headers
280 * on inner IPv6 packet (since they are now encapsulated).
281 *
282 * IPv6 [ESP|AH] IPv6 [extension headers] payload
283 */
284
285 /*
286 * If we need to encapsulate the packet, do it here
287 * ipsec6_proces_packet will send the packet using ip6_output
288 */
289 error = ipsec6_process_packet(m, sp->req);
290
291 KEY_FREESP(&sp);
292
293 if (error == EJUSTRETURN) {
294 /*
295 * We had a SP with a level of 'use' and no SA. We
296 * will just continue to process the packet without
297 * IPsec processing.
298 */
299 error = 0;
300 goto skip_ipsec;
301 }
302
303 if (error) {
304 /* mbuf is already reclaimed in ipsec6_process_packet. */
305 switch (error) {
306 case EHOSTUNREACH:
307 case ENETUNREACH:
308 case EMSGSIZE:
309 case ENOBUFS:
310 case ENOMEM:
311 break;
312 default:
313 printf("ip6_output (ipsec): error code %d\n", error);
314 /* FALLTHROUGH */
315 case ENOENT:
316 /* don't show these error codes to the user */
317 break;
318 }
319 IP6STAT_INC(ip6s_cantforward);
320 if (mcopy) {
321#if 0
322 /* XXX: what icmp ? */
323#else
324 m_freem(mcopy);
325#endif
326 }
327 return;
328 } else {
329 /*
330 * In the FAST IPSec case we have already
331 * re-injected the packet and it has been freed
332 * by the ipsec_done() function. So, just clean
333 * up after ourselves.
334 */
335 m = NULL;
336 goto freecopy;
337 }
338 }
339skip_ipsec:
340#endif
341again:
342 bzero(&rin6, sizeof(struct route_in6));
343 dst = (struct sockaddr_in6 *)&rin6.ro_dst;
344 dst->sin6_len = sizeof(struct sockaddr_in6);
345 dst->sin6_family = AF_INET6;
346 dst->sin6_addr = ip6->ip6_dst;
347again2:
348 rin6.ro_rt = in6_rtalloc1((struct sockaddr *)dst, 0, 0, M_GETFIB(m));
349 if (rin6.ro_rt != NULL)
350 RT_UNLOCK(rin6.ro_rt);
351 else {
352 IP6STAT_INC(ip6s_noroute);
353 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
354 if (mcopy) {
355 icmp6_error(mcopy, ICMP6_DST_UNREACH,
356 ICMP6_DST_UNREACH_NOROUTE, 0);
357 }
358 goto bad;
359 }
360 rt = rin6.ro_rt;
361
362 /*
363 * Source scope check: if a packet can't be delivered to its
364 * destination for the reason that the destination is beyond the scope
365 * of the source address, discard the packet and return an icmp6
366 * destination unreachable error with Code 2 (beyond scope of source
367 * address). We use a local copy of ip6_src, since in6_setscope()
368 * will possibly modify its first argument.
369 * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1]
370 */
371 src_in6 = ip6->ip6_src;
372 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) {
373 /* XXX: this should not happen */
374 IP6STAT_INC(ip6s_cantforward);
375 IP6STAT_INC(ip6s_badscope);
376 goto bad;
377 }
378 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) {
379 IP6STAT_INC(ip6s_cantforward);
380 IP6STAT_INC(ip6s_badscope);
381 goto bad;
382 }
383 if (inzone != outzone) {
384 IP6STAT_INC(ip6s_cantforward);
385 IP6STAT_INC(ip6s_badscope);
386 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
387
388 if (V_ip6_log_time + V_ip6_log_interval < time_uptime) {
389 V_ip6_log_time = time_uptime;
390 log(LOG_DEBUG,
391 "cannot forward "
392 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
393 ip6_sprintf(ip6bufs, &ip6->ip6_src),
394 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
395 ip6->ip6_nxt,
396 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
397 }
398 if (mcopy)
399 icmp6_error(mcopy, ICMP6_DST_UNREACH,
400 ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
401 goto bad;
402 }
403
404 /*
405 * Destination scope check: if a packet is going to break the scope
406 * zone of packet's destination address, discard it. This case should
407 * usually be prevented by appropriately-configured routing table, but
408 * we need an explicit check because we may mistakenly forward the
409 * packet to a different zone by (e.g.) a default route.
410 */
411 dst_in6 = ip6->ip6_dst;
412 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
413 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
414 inzone != outzone) {
415 IP6STAT_INC(ip6s_cantforward);
416 IP6STAT_INC(ip6s_badscope);
417 goto bad;
418 }
419
420 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
421 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
422 if (mcopy) {
423 u_long mtu;
424#ifdef IPSEC
425 struct secpolicy *sp;
426 int ipsecerror;
427 size_t ipsechdrsiz;
428#endif /* IPSEC */
429
430 mtu = IN6_LINKMTU(rt->rt_ifp);
431#ifdef IPSEC
432 /*
433 * When we do IPsec tunnel ingress, we need to play
434 * with the link value (decrement IPsec header size
435 * from mtu value). The code is much simpler than v4
436 * case, as we have the outgoing interface for
437 * encapsulated packet as "rt->rt_ifp".
438 */
439 sp = ipsec_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
440 IP_FORWARDING, &ipsecerror);
441 if (sp) {
442 ipsechdrsiz = ipsec_hdrsiz(mcopy,
443 IPSEC_DIR_OUTBOUND, NULL);
444 if (ipsechdrsiz < mtu)
445 mtu -= ipsechdrsiz;
446 }
447
448 /*
449 * if mtu becomes less than minimum MTU,
450 * tell minimum MTU (and I'll need to fragment it).
451 */
452 if (mtu < IPV6_MMTU)
453 mtu = IPV6_MMTU;
454#endif /* IPSEC */
455 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
456 }
457 goto bad;
458 }
459
460 if (rt->rt_flags & RTF_GATEWAY)
461 dst = (struct sockaddr_in6 *)rt->rt_gateway;
462
463 /*
464 * If we are to forward the packet using the same interface
465 * as one we got the packet from, perhaps we should send a redirect
466 * to sender to shortcut a hop.
467 * Only send redirect if source is sending directly to us,
468 * and if packet was not source routed (or has any options).
469 * Also, don't send redirect if forwarding using a route
470 * modified by a redirect.
471 */
472 if (V_ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
473 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
474 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
475 /*
476 * If the incoming interface is equal to the outgoing
477 * one, and the link attached to the interface is
478 * point-to-point, then it will be highly probable
479 * that a routing loop occurs. Thus, we immediately
480 * drop the packet and send an ICMPv6 error message.
481 *
482 * type/code is based on suggestion by Rich Draves.
483 * not sure if it is the best pick.
484 */
485 icmp6_error(mcopy, ICMP6_DST_UNREACH,
486 ICMP6_DST_UNREACH_ADDR, 0);
487 goto bad;
488 }
489 type = ND_REDIRECT;
490 }
491
492 /*
493 * Fake scoped addresses. Note that even link-local source or
494 * destinaion can appear, if the originating node just sends the
495 * packet to us (without address resolution for the destination).
496 * Since both icmp6_error and icmp6_redirect_output fill the embedded
497 * link identifiers, we can do this stuff after making a copy for
498 * returning an error.
499 */
500 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
501 /*
502 * See corresponding comments in ip6_output.
503 * XXX: but is it possible that ip6_forward() sends a packet
504 * to a loopback interface? I don't think so, and thus
505 * I bark here. (jinmei@kame.net)
506 * XXX: it is common to route invalid packets to loopback.
507 * also, the codepath will be visited on use of ::1 in
508 * rthdr. (itojun)
509 */
510#if 1
511 if (0)
512#else
513 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
514#endif
515 {
516 printf("ip6_forward: outgoing interface is loopback. "
517 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
518 ip6_sprintf(ip6bufs, &ip6->ip6_src),
519 ip6_sprintf(ip6bufd, &ip6->ip6_dst),
520 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
521 if_name(rt->rt_ifp));
522 }
523
524 /* we can just use rcvif in forwarding. */
525 origifp = m->m_pkthdr.rcvif;
526 }
527 else
528 origifp = rt->rt_ifp;
529 /*
530 * clear embedded scope identifiers if necessary.
531 * in6_clearscope will touch the addresses only when necessary.
532 */
533 in6_clearscope(&ip6->ip6_src);
534 in6_clearscope(&ip6->ip6_dst);
535
536 /* Jump over all PFIL processing if hooks are not active. */
537 if (!PFIL_HOOKED(&V_inet6_pfil_hook))
538 goto pass;
539
540 odst = ip6->ip6_dst;
541 /* Run through list of hooks for output packets. */
542 error = pfil_run_hooks(&V_inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT, NULL);
543 if (error != 0 || m == NULL)
544 goto freecopy; /* consumed by filter */
545 ip6 = mtod(m, struct ip6_hdr *);
546
547 /* See if destination IP address was changed by packet filter. */
548 if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst)) {
549 m->m_flags |= M_SKIP_FIREWALL;
550 /* If destination is now ourself drop to ip6_input(). */
551 if (in6_localip(&ip6->ip6_dst)) {
552 m->m_flags |= M_FASTFWD_OURS;
553 if (m->m_pkthdr.rcvif == NULL)
554 m->m_pkthdr.rcvif = V_loif;
555 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
556 m->m_pkthdr.csum_flags |=
557 CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
558 m->m_pkthdr.csum_data = 0xffff;
559 }
560#ifdef SCTP
561 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
562 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
563#endif
564 error = netisr_queue(NETISR_IPV6, m);
565 goto out;
566 } else
567 goto again; /* Redo the routing table lookup. */
568 }
569
570 /* See if local, if yes, send it to netisr. */
571 if (m->m_flags & M_FASTFWD_OURS) {
572 if (m->m_pkthdr.rcvif == NULL)
573 m->m_pkthdr.rcvif = V_loif;
574 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
575 m->m_pkthdr.csum_flags |=
576 CSUM_DATA_VALID_IPV6 | CSUM_PSEUDO_HDR;
577 m->m_pkthdr.csum_data = 0xffff;
578 }
579#ifdef SCTP
580 if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6)
581 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID;
582#endif
583 error = netisr_queue(NETISR_IPV6, m);
584 goto out;
585 }
586 /* Or forward to some other address? */
587 if ((m->m_flags & M_IP6_NEXTHOP) &&
588 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) {
589 dst = (struct sockaddr_in6 *)&rin6.ro_dst;
590 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in6));
591 m->m_flags |= M_SKIP_FIREWALL;
592 m->m_flags &= ~M_IP6_NEXTHOP;
593 m_tag_delete(m, fwd_tag);
594 goto again2;
595 }
596
597pass:
598 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
599 if (error) {
600 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
601 IP6STAT_INC(ip6s_cantforward);
602 } else {
603 IP6STAT_INC(ip6s_forward);
604 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
605 if (type)
606 IP6STAT_INC(ip6s_redirectsent);
607 else {
608 if (mcopy)
609 goto freecopy;
610 }
611 }
612
613 if (mcopy == NULL)
614 goto out;
615 switch (error) {
616 case 0:
617 if (type == ND_REDIRECT) {
618 icmp6_redirect_output(mcopy, rt);
619 goto out;
620 }
621 goto freecopy;
622
623 case EMSGSIZE:
624 /* xxx MTU is constant in PPP? */
625 goto freecopy;
626
627 case ENOBUFS:
628 /* Tell source to slow down like source quench in IP? */
629 goto freecopy;
630
631 case ENETUNREACH: /* shouldn't happen, checked above */
632 case EHOSTUNREACH:
633 case ENETDOWN:
634 case EHOSTDOWN:
635 default:
636 type = ICMP6_DST_UNREACH;
637 code = ICMP6_DST_UNREACH_ADDR;
638 break;
639 }
640 icmp6_error(mcopy, type, code, 0);
641 goto out;
642
643 freecopy:
644 m_freem(mcopy);
645 goto out;
646bad:
647 m_freem(m);
648out:
649 if (rt != NULL)
650 RTFREE(rt);
651}
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