1 | /* |
2 | * Copyright (c) 2009-2016 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 |
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13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
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17 | * |
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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> |
97 | extern int ipsec_bypass; |
98 | #endif /* IPSEC */ |
99 | |
100 | #include <net/net_osdep.h> |
101 | |
102 | #if DUMMYNET |
103 | #include <netinet/ip_fw.h> |
104 | #include <netinet/ip_dummynet.h> |
105 | #endif /* DUMMYNET */ |
106 | |
107 | #if PF |
108 | #include <net/pfvar.h> |
109 | #endif /* PF */ |
110 | |
111 | /* |
112 | * Forward a packet. If some error occurs return the sender |
113 | * an icmp packet. Note we can't always generate a meaningful |
114 | * icmp message because icmp doesn't have a large enough repertoire |
115 | * of codes and types. |
116 | * |
117 | * If not forwarding, just drop the packet. This could be confusing |
118 | * if ipforwarding was zero but some routing protocol was advancing |
119 | * us as a gateway to somewhere. However, we must let the routing |
120 | * protocol deal with that. |
121 | * |
122 | */ |
123 | |
124 | struct mbuf * |
125 | ip6_forward(struct mbuf *m, struct route_in6 *ip6forward_rt, |
126 | int srcrt) |
127 | { |
128 | struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); |
129 | struct sockaddr_in6 *dst; |
130 | struct rtentry *rt; |
131 | int error, type = 0, code = 0; |
132 | boolean_t proxy = FALSE; |
133 | struct mbuf *mcopy = NULL; |
134 | struct ifnet *ifp, *rcvifp, *origifp; /* maybe unnecessary */ |
135 | u_int32_t inzone, outzone, len; |
136 | struct in6_addr src_in6, dst_in6; |
137 | uint64_t curtime = net_uptime(); |
138 | #if IPSEC |
139 | struct secpolicy *sp = NULL; |
140 | #endif |
141 | unsigned int ifscope = IFSCOPE_NONE; |
142 | #if PF |
143 | struct pf_mtag *pf_mtag; |
144 | #endif /* PF */ |
145 | |
146 | /* |
147 | * In the prefix proxying case, the route to the proxied node normally |
148 | * gets created by nd6_prproxy_ns_output(), as part of forwarding a |
149 | * NS (NUD/AR) packet to the proxied node. In the event that such |
150 | * packet did not arrive in time before the correct route gets created, |
151 | * ip6_input() would have performed a rtalloc() which most likely will |
152 | * create the wrong cloned route; this route points back to the same |
153 | * interface as the inbound interface, since the parent non-scoped |
154 | * prefix route points there. Therefore we check if that is the case |
155 | * and perform the necessary fixup to get the correct route installed. |
156 | */ |
157 | if (!srcrt && nd6_prproxy && |
158 | (rt = ip6forward_rt->ro_rt) != NULL && (rt->rt_flags & RTF_PROXY)) { |
159 | nd6_proxy_find_fwdroute(m->m_pkthdr.rcvif, ip6forward_rt); |
160 | if ((rt = ip6forward_rt->ro_rt) != NULL) |
161 | ifscope = rt->rt_ifp->if_index; |
162 | } |
163 | |
164 | #if PF |
165 | pf_mtag = pf_find_mtag(m); |
166 | if (pf_mtag != NULL && pf_mtag->pftag_rtableid != IFSCOPE_NONE) |
167 | ifscope = pf_mtag->pftag_rtableid; |
168 | |
169 | /* |
170 | * If the caller provides a route which is on a different interface |
171 | * than the one specified for scoped forwarding, discard the route |
172 | * and do a lookup below. |
173 | */ |
174 | if (ifscope != IFSCOPE_NONE && (rt = ip6forward_rt->ro_rt) != NULL) { |
175 | RT_LOCK(rt); |
176 | if (rt->rt_ifp->if_index != ifscope) { |
177 | RT_UNLOCK(rt); |
178 | ROUTE_RELEASE(ip6forward_rt); |
179 | rt = NULL; |
180 | } else { |
181 | RT_UNLOCK(rt); |
182 | } |
183 | } |
184 | #endif /* PF */ |
185 | |
186 | #if IPSEC |
187 | /* |
188 | * Check AH/ESP integrity. |
189 | */ |
190 | /* |
191 | * Don't increment ip6s_cantforward because this is the check |
192 | * before forwarding packet actually. |
193 | */ |
194 | if (ipsec_bypass == 0) { |
195 | if (ipsec6_in_reject(m, NULL)) { |
196 | IPSEC_STAT_INCREMENT(ipsec6stat.in_polvio); |
197 | m_freem(m); |
198 | return (NULL); |
199 | } |
200 | } |
201 | #endif /*IPSEC*/ |
202 | |
203 | /* |
204 | * Do not forward packets to multicast destination. |
205 | * Do not forward packets with unspecified source. It was discussed |
206 | * in July 2000, on ipngwg mailing list. |
207 | */ |
208 | if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || |
209 | IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || |
210 | IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { |
211 | ip6stat.ip6s_cantforward++; |
212 | /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ |
213 | if (ip6_log_time + ip6_log_interval < curtime) { |
214 | ip6_log_time = curtime; |
215 | log(LOG_DEBUG, |
216 | "cannot forward " |
217 | "from %s to %s nxt %d received on %s\n" , |
218 | ip6_sprintf(&ip6->ip6_src), |
219 | ip6_sprintf(&ip6->ip6_dst), |
220 | ip6->ip6_nxt, |
221 | if_name(m->m_pkthdr.rcvif)); |
222 | } |
223 | m_freem(m); |
224 | return (NULL); |
225 | } |
226 | |
227 | if (ip6->ip6_hlim <= IPV6_HLIMDEC) { |
228 | /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ |
229 | icmp6_error_flag(m, ICMP6_TIME_EXCEEDED, |
230 | ICMP6_TIME_EXCEED_TRANSIT, 0, 0); |
231 | return (NULL); |
232 | } |
233 | |
234 | /* |
235 | * See if the destination is a proxied address, and if so pretend |
236 | * that it's for us. This is mostly to handle NUD probes against |
237 | * the proxied addresses. We filter for ICMPv6 here and will let |
238 | * icmp6_input handle the rest. |
239 | */ |
240 | if (!srcrt && nd6_prproxy) { |
241 | VERIFY(!IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)); |
242 | proxy = nd6_prproxy_isours(m, ip6, ip6forward_rt, ifscope); |
243 | /* |
244 | * Don't update hop limit while proxying; RFC 4389 4.1. |
245 | * Also skip IPsec forwarding path processing as this |
246 | * packet is not to be forwarded. |
247 | */ |
248 | if (proxy) |
249 | goto skip_ipsec; |
250 | } |
251 | |
252 | ip6->ip6_hlim -= IPV6_HLIMDEC; |
253 | |
254 | /* |
255 | * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - |
256 | * size of IPv6 + ICMPv6 headers) bytes of the packet in case |
257 | * we need to generate an ICMP6 message to the src. |
258 | * Thanks to M_EXT, in most cases copy will not occur. |
259 | * |
260 | * It is important to save it before IPsec processing as IPsec |
261 | * processing may modify the mbuf. |
262 | */ |
263 | mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); |
264 | |
265 | #if IPSEC |
266 | if (ipsec_bypass != 0) |
267 | goto skip_ipsec; |
268 | /* get a security policy for this packet */ |
269 | sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, IP_FORWARDING, |
270 | &error); |
271 | if (sp == NULL) { |
272 | IPSEC_STAT_INCREMENT(ipsec6stat.out_inval); |
273 | ip6stat.ip6s_cantforward++; |
274 | if (mcopy) { |
275 | #if 0 |
276 | /* XXX: what icmp ? */ |
277 | #else |
278 | m_freem(mcopy); |
279 | #endif |
280 | } |
281 | m_freem(m); |
282 | return (NULL); |
283 | } |
284 | |
285 | error = 0; |
286 | |
287 | /* check policy */ |
288 | switch (sp->policy) { |
289 | case IPSEC_POLICY_DISCARD: |
290 | case IPSEC_POLICY_GENERATE: |
291 | /* |
292 | * This packet is just discarded. |
293 | */ |
294 | IPSEC_STAT_INCREMENT(ipsec6stat.out_polvio); |
295 | ip6stat.ip6s_cantforward++; |
296 | key_freesp(sp, KEY_SADB_UNLOCKED); |
297 | if (mcopy) { |
298 | #if 0 |
299 | /* XXX: what icmp ? */ |
300 | #else |
301 | m_freem(mcopy); |
302 | #endif |
303 | } |
304 | m_freem(m); |
305 | return (NULL); |
306 | |
307 | case IPSEC_POLICY_BYPASS: |
308 | case IPSEC_POLICY_NONE: |
309 | /* no need to do IPsec. */ |
310 | key_freesp(sp, KEY_SADB_UNLOCKED); |
311 | goto skip_ipsec; |
312 | |
313 | case IPSEC_POLICY_IPSEC: |
314 | if (sp->req == NULL) { |
315 | /* XXX should be panic ? */ |
316 | printf("ip6_forward: No IPsec request specified.\n" ); |
317 | ip6stat.ip6s_cantforward++; |
318 | key_freesp(sp, KEY_SADB_UNLOCKED); |
319 | if (mcopy) { |
320 | #if 0 |
321 | /* XXX: what icmp ? */ |
322 | #else |
323 | m_freem(mcopy); |
324 | #endif |
325 | } |
326 | m_freem(m); |
327 | return (NULL); |
328 | } |
329 | /* do IPsec */ |
330 | break; |
331 | |
332 | case IPSEC_POLICY_ENTRUST: |
333 | default: |
334 | /* should be panic ?? */ |
335 | printf("ip6_forward: Invalid policy found. %d\n" , sp->policy); |
336 | key_freesp(sp, KEY_SADB_UNLOCKED); |
337 | goto skip_ipsec; |
338 | } |
339 | |
340 | { |
341 | struct ipsec_output_state state; |
342 | |
343 | /* |
344 | * All the extension headers will become inaccessible |
345 | * (since they can be encrypted). |
346 | * Don't panic, we need no more updates to extension headers |
347 | * on inner IPv6 packet (since they are now encapsulated). |
348 | * |
349 | * IPv6 [ESP|AH] IPv6 [extension headers] payload |
350 | */ |
351 | bzero(&state, sizeof(state)); |
352 | state.m = m; |
353 | state.dst = NULL; /* update at ipsec6_output_tunnel() */ |
354 | |
355 | error = ipsec6_output_tunnel(&state, sp, 0); |
356 | key_freesp(sp, KEY_SADB_UNLOCKED); |
357 | if (state.tunneled == 4) { |
358 | ROUTE_RELEASE(&state.ro); |
359 | return (NULL); /* packet is gone - sent over IPv4 */ |
360 | } |
361 | |
362 | m = state.m; |
363 | ROUTE_RELEASE(&state.ro); |
364 | |
365 | if (error) { |
366 | /* mbuf is already reclaimed in ipsec6_output_tunnel. */ |
367 | switch (error) { |
368 | case EHOSTUNREACH: |
369 | case ENETUNREACH: |
370 | case EMSGSIZE: |
371 | case ENOBUFS: |
372 | case ENOMEM: |
373 | break; |
374 | default: |
375 | printf("ip6_output (ipsec): error code %d\n" , error); |
376 | /* fall through */ |
377 | case ENOENT: |
378 | /* don't show these error codes to the user */ |
379 | break; |
380 | } |
381 | ip6stat.ip6s_cantforward++; |
382 | if (mcopy) { |
383 | #if 0 |
384 | /* XXX: what icmp ? */ |
385 | #else |
386 | m_freem(mcopy); |
387 | #endif |
388 | } |
389 | m_freem(m); |
390 | return (NULL); |
391 | } |
392 | } |
393 | #endif /* IPSEC */ |
394 | skip_ipsec: |
395 | |
396 | dst = (struct sockaddr_in6 *)&ip6forward_rt->ro_dst; |
397 | if ((rt = ip6forward_rt->ro_rt) != NULL) { |
398 | RT_LOCK(rt); |
399 | /* Take an extra ref for ourselves */ |
400 | RT_ADDREF_LOCKED(rt); |
401 | } |
402 | |
403 | VERIFY(rt == NULL || rt == ip6forward_rt->ro_rt); |
404 | if (!srcrt) { |
405 | /* |
406 | * ip6forward_rt->ro_dst.sin6_addr is equal to ip6->ip6_dst |
407 | */ |
408 | if (ROUTE_UNUSABLE(ip6forward_rt)) { |
409 | if (rt != NULL) { |
410 | /* Release extra ref */ |
411 | RT_REMREF_LOCKED(rt); |
412 | RT_UNLOCK(rt); |
413 | } |
414 | ROUTE_RELEASE(ip6forward_rt); |
415 | |
416 | /* this probably fails but give it a try again */ |
417 | rtalloc_scoped_ign((struct route *)ip6forward_rt, |
418 | RTF_PRCLONING, ifscope); |
419 | if ((rt = ip6forward_rt->ro_rt) != NULL) { |
420 | RT_LOCK(rt); |
421 | /* Take an extra ref for ourselves */ |
422 | RT_ADDREF_LOCKED(rt); |
423 | } |
424 | } |
425 | |
426 | if (rt == NULL) { |
427 | ip6stat.ip6s_noroute++; |
428 | in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); |
429 | if (mcopy) |
430 | icmp6_error(mcopy, ICMP6_DST_UNREACH, |
431 | ICMP6_DST_UNREACH_NOROUTE, 0); |
432 | m_freem(m); |
433 | return (NULL); |
434 | } |
435 | RT_LOCK_ASSERT_HELD(rt); |
436 | } else if (ROUTE_UNUSABLE(ip6forward_rt) || |
437 | !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { |
438 | if (rt != NULL) { |
439 | /* Release extra ref */ |
440 | RT_REMREF_LOCKED(rt); |
441 | RT_UNLOCK(rt); |
442 | } |
443 | ROUTE_RELEASE(ip6forward_rt); |
444 | |
445 | bzero(dst, sizeof(*dst)); |
446 | dst->sin6_len = sizeof(struct sockaddr_in6); |
447 | dst->sin6_family = AF_INET6; |
448 | dst->sin6_addr = ip6->ip6_dst; |
449 | |
450 | rtalloc_scoped_ign((struct route *)ip6forward_rt, |
451 | RTF_PRCLONING, ifscope); |
452 | if ((rt = ip6forward_rt->ro_rt) == NULL) { |
453 | ip6stat.ip6s_noroute++; |
454 | in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); |
455 | if (mcopy) |
456 | icmp6_error(mcopy, ICMP6_DST_UNREACH, |
457 | ICMP6_DST_UNREACH_NOROUTE, 0); |
458 | m_freem(m); |
459 | return (NULL); |
460 | } |
461 | RT_LOCK(rt); |
462 | /* Take an extra ref for ourselves */ |
463 | RT_ADDREF_LOCKED(rt); |
464 | } |
465 | |
466 | /* |
467 | * Source scope check: if a packet can't be delivered to its |
468 | * destination for the reason that the destination is beyond the scope |
469 | * of the source address, discard the packet and return an icmp6 |
470 | * destination unreachable error with Code 2 (beyond scope of source |
471 | * address) unless we are proxying (source address is link local |
472 | * for NUDs.) We use a local copy of ip6_src, since in6_setscope() |
473 | * will possibly modify its first argument. |
474 | * [draft-ietf-ipngwg-icmp-v3-04.txt, Section 3.1] |
475 | */ |
476 | src_in6 = ip6->ip6_src; |
477 | if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { |
478 | RT_REMREF_LOCKED(rt); |
479 | RT_UNLOCK(rt); |
480 | /* XXX: this should not happen */ |
481 | ip6stat.ip6s_cantforward++; |
482 | ip6stat.ip6s_badscope++; |
483 | m_freem(m); |
484 | return (NULL); |
485 | } |
486 | if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { |
487 | RT_REMREF_LOCKED(rt); |
488 | RT_UNLOCK(rt); |
489 | ip6stat.ip6s_cantforward++; |
490 | ip6stat.ip6s_badscope++; |
491 | m_freem(m); |
492 | return (NULL); |
493 | } |
494 | |
495 | if (inzone != outzone && !proxy) { |
496 | ip6stat.ip6s_cantforward++; |
497 | ip6stat.ip6s_badscope++; |
498 | in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); |
499 | |
500 | if (ip6_log_time + ip6_log_interval < curtime) { |
501 | ip6_log_time = curtime; |
502 | log(LOG_DEBUG, |
503 | "cannot forward " |
504 | "src %s, dst %s, nxt %d, rcvif %s, outif %s\n" , |
505 | ip6_sprintf(&ip6->ip6_src), |
506 | ip6_sprintf(&ip6->ip6_dst), |
507 | ip6->ip6_nxt, |
508 | if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); |
509 | } |
510 | /* Release extra ref */ |
511 | RT_REMREF_LOCKED(rt); |
512 | RT_UNLOCK(rt); |
513 | if (mcopy) { |
514 | icmp6_error(mcopy, ICMP6_DST_UNREACH, |
515 | ICMP6_DST_UNREACH_BEYONDSCOPE, 0); |
516 | } |
517 | m_freem(m); |
518 | return (NULL); |
519 | } |
520 | |
521 | /* |
522 | * Destination scope check: if a packet is going to break the scope |
523 | * zone of packet's destination address, discard it. This case should |
524 | * usually be prevented by appropriately-configured routing table, but |
525 | * we need an explicit check because we may mistakenly forward the |
526 | * packet to a different zone by (e.g.) a default route. |
527 | */ |
528 | dst_in6 = ip6->ip6_dst; |
529 | if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || |
530 | in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || |
531 | inzone != outzone) { |
532 | RT_REMREF_LOCKED(rt); |
533 | RT_UNLOCK(rt); |
534 | ip6stat.ip6s_cantforward++; |
535 | ip6stat.ip6s_badscope++; |
536 | m_freem(m); |
537 | return (NULL); |
538 | } |
539 | |
540 | if (m->m_pkthdr.len > rt->rt_ifp->if_mtu) { |
541 | in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); |
542 | if (mcopy) { |
543 | uint32_t mtu; |
544 | #if IPSEC |
545 | struct secpolicy *sp2; |
546 | int ipsecerror; |
547 | size_t ipsechdrsiz; |
548 | #endif |
549 | |
550 | mtu = rt->rt_ifp->if_mtu; |
551 | #if IPSEC |
552 | /* |
553 | * When we do IPsec tunnel ingress, we need to play |
554 | * with the link value (decrement IPsec header size |
555 | * from mtu value). The code is much simpler than v4 |
556 | * case, as we have the outgoing interface for |
557 | * encapsulated packet as "rt->rt_ifp". |
558 | */ |
559 | sp2 = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, |
560 | IP_FORWARDING, &ipsecerror); |
561 | if (sp2) { |
562 | ipsechdrsiz = ipsec6_hdrsiz(mcopy, |
563 | IPSEC_DIR_OUTBOUND, NULL); |
564 | if (ipsechdrsiz < mtu) |
565 | mtu -= ipsechdrsiz; |
566 | key_freesp(sp2, KEY_SADB_UNLOCKED); |
567 | } |
568 | /* |
569 | * if mtu becomes less than minimum MTU, |
570 | * tell minimum MTU (and I'll need to fragment it). |
571 | */ |
572 | if (mtu < IPV6_MMTU) |
573 | mtu = IPV6_MMTU; |
574 | #endif |
575 | /* Release extra ref */ |
576 | RT_REMREF_LOCKED(rt); |
577 | RT_UNLOCK(rt); |
578 | icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); |
579 | } else { |
580 | /* Release extra ref */ |
581 | RT_REMREF_LOCKED(rt); |
582 | RT_UNLOCK(rt); |
583 | } |
584 | m_freem(m); |
585 | return (NULL); |
586 | } |
587 | |
588 | if (rt->rt_flags & RTF_GATEWAY) |
589 | dst = (struct sockaddr_in6 *)(void *)rt->rt_gateway; |
590 | |
591 | /* |
592 | * If we are to forward the packet using the same interface |
593 | * as one we got the packet from, perhaps we should send a redirect |
594 | * to sender to shortcut a hop. |
595 | * Only send redirect if source is sending directly to us, |
596 | * and if packet was not source routed (or has any options). |
597 | * Also, don't send redirect if forwarding using a route |
598 | * modified by a redirect. |
599 | */ |
600 | if (!proxy && |
601 | ip6_sendredirects && rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && |
602 | (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { |
603 | if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { |
604 | /* |
605 | * If the incoming interface is equal to the outgoing |
606 | * one, and the link attached to the interface is |
607 | * point-to-point, then it will be highly probable |
608 | * that a routing loop occurs. Thus, we immediately |
609 | * drop the packet and send an ICMPv6 error message. |
610 | * |
611 | * type/code is based on suggestion by Rich Draves. |
612 | * not sure if it is the best pick. |
613 | */ |
614 | RT_REMREF_LOCKED(rt); /* Release extra ref */ |
615 | RT_UNLOCK(rt); |
616 | icmp6_error(mcopy, ICMP6_DST_UNREACH, |
617 | ICMP6_DST_UNREACH_ADDR, 0); |
618 | m_freem(m); |
619 | return (NULL); |
620 | } |
621 | type = ND_REDIRECT; |
622 | } |
623 | /* |
624 | * Fake scoped addresses. Note that even link-local source or |
625 | * destinaion can appear, if the originating node just sends the |
626 | * packet to us (without address resolution for the destination). |
627 | * Since both icmp6_error and icmp6_redirect_output fill the embedded |
628 | * link identifiers, we can do this stuff after making a copy for |
629 | * returning an error. |
630 | */ |
631 | if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { |
632 | /* |
633 | * See corresponding comments in ip6_output. |
634 | * XXX: but is it possible that ip6_forward() sends a packet |
635 | * to a loopback interface? I don't think so, and thus |
636 | * I bark here. (jinmei@kame.net) |
637 | * XXX: it is common to route invalid packets to loopback. |
638 | * also, the codepath will be visited on use of ::1 in |
639 | * rthdr. (itojun) |
640 | */ |
641 | #if 1 |
642 | if ((0)) |
643 | #else |
644 | if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) |
645 | #endif |
646 | { |
647 | printf("ip6_forward: outgoing interface is loopback. " |
648 | "src %s, dst %s, nxt %d, rcvif %s, outif %s\n" , |
649 | ip6_sprintf(&ip6->ip6_src), |
650 | ip6_sprintf(&ip6->ip6_dst), |
651 | ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), |
652 | if_name(rt->rt_ifp)); |
653 | } |
654 | |
655 | /* we can just use rcvif in forwarding. */ |
656 | origifp = rcvifp = m->m_pkthdr.rcvif; |
657 | } else if (nd6_prproxy) { |
658 | /* |
659 | * In the prefix proxying case, we need to inform nd6_output() |
660 | * about the inbound interface, so that any subsequent NS |
661 | * packets generated by nd6_prproxy_ns_output() will not be |
662 | * sent back to that same interface. |
663 | */ |
664 | origifp = rcvifp = m->m_pkthdr.rcvif; |
665 | } else { |
666 | rcvifp = m->m_pkthdr.rcvif; |
667 | origifp = rt->rt_ifp; |
668 | } |
669 | /* |
670 | * clear embedded scope identifiers if necessary. |
671 | * in6_clearscope will touch the addresses only when necessary. |
672 | */ |
673 | in6_clearscope(&ip6->ip6_src); |
674 | in6_clearscope(&ip6->ip6_dst); |
675 | |
676 | ifp = rt->rt_ifp; |
677 | /* Drop the lock but retain the extra ref */ |
678 | RT_UNLOCK(rt); |
679 | |
680 | /* |
681 | * If this is to be processed locally, let ip6_input have it. |
682 | */ |
683 | if (proxy) { |
684 | VERIFY(m->m_pkthdr.pkt_flags & PKTF_PROXY_DST); |
685 | /* Release extra ref */ |
686 | RT_REMREF(rt); |
687 | if (mcopy != NULL) |
688 | m_freem(mcopy); |
689 | return (m); |
690 | } |
691 | |
692 | /* Mark this packet as being forwarded from another interface */ |
693 | m->m_pkthdr.pkt_flags |= PKTF_FORWARDED; |
694 | |
695 | #if PF |
696 | if (PF_IS_ENABLED) { |
697 | #if DUMMYNET |
698 | struct ip_fw_args args; |
699 | bzero(&args, sizeof(args)); |
700 | |
701 | args.fwa_m = m; |
702 | args.fwa_oif = ifp; |
703 | args.fwa_oflags = 0; |
704 | args.fwa_ro6 = ip6forward_rt; |
705 | args.fwa_ro6_pmtu = ip6forward_rt; |
706 | args.fwa_mtu = rt->rt_ifp->if_mtu; |
707 | args.fwa_dst6 = dst; |
708 | args.fwa_origifp = origifp; |
709 | /* Invoke outbound packet filter */ |
710 | error = pf_af_hook(ifp, NULL, &m, AF_INET6, FALSE, &args); |
711 | #else /* !DUMMYNET */ |
712 | error = pf_af_hook(ifp, NULL, &m, AF_INET6, FALSE, NULL); |
713 | #endif /* !DUMMYNET */ |
714 | if (error != 0 || m == NULL) { |
715 | if (m != NULL) { |
716 | panic("%s: unexpected packet %p\n" , __func__, m); |
717 | /* NOTREACHED */ |
718 | } |
719 | /* Already freed by callee */ |
720 | goto senderr; |
721 | } |
722 | /* |
723 | * We do not use ip6 header again in the code below, |
724 | * however still adding the bit here so that any new |
725 | * code in future doesn't end up working with the |
726 | * wrong pointer |
727 | */ |
728 | ip6 = mtod(m, struct ip6_hdr *); |
729 | } |
730 | #endif /* PF */ |
731 | |
732 | len = m_pktlen(m); |
733 | error = nd6_output(ifp, origifp, m, dst, rt, NULL); |
734 | if (error) { |
735 | in6_ifstat_inc(ifp, ifs6_out_discard); |
736 | ip6stat.ip6s_cantforward++; |
737 | } else { |
738 | /* |
739 | * Increment stats on the source interface; the ones |
740 | * for destination interface has been taken care of |
741 | * during output above by virtue of PKTF_FORWARDED. |
742 | */ |
743 | rcvifp->if_fpackets++; |
744 | rcvifp->if_fbytes += len; |
745 | |
746 | ip6stat.ip6s_forward++; |
747 | in6_ifstat_inc(ifp, ifs6_out_forward); |
748 | if (type) |
749 | ip6stat.ip6s_redirectsent++; |
750 | else { |
751 | if (mcopy) { |
752 | goto freecopy; |
753 | } |
754 | } |
755 | } |
756 | #if PF |
757 | senderr: |
758 | #endif /* PF */ |
759 | if (mcopy == NULL) { |
760 | /* Release extra ref */ |
761 | RT_REMREF(rt); |
762 | return (NULL); |
763 | } |
764 | switch (error) { |
765 | case 0: |
766 | #if 1 |
767 | if (type == ND_REDIRECT) { |
768 | icmp6_redirect_output(mcopy, rt); |
769 | /* Release extra ref */ |
770 | RT_REMREF(rt); |
771 | return (NULL); |
772 | } |
773 | #endif |
774 | goto freecopy; |
775 | |
776 | case EMSGSIZE: |
777 | /* xxx MTU is constant in PPP? */ |
778 | goto freecopy; |
779 | |
780 | case ENOBUFS: |
781 | /* Tell source to slow down like source quench in IP? */ |
782 | goto freecopy; |
783 | |
784 | case ENETUNREACH: /* shouldn't happen, checked above */ |
785 | case EHOSTUNREACH: |
786 | case ENETDOWN: |
787 | case EHOSTDOWN: |
788 | default: |
789 | type = ICMP6_DST_UNREACH; |
790 | code = ICMP6_DST_UNREACH_ADDR; |
791 | break; |
792 | } |
793 | icmp6_error(mcopy, type, code, 0); |
794 | /* Release extra ref */ |
795 | RT_REMREF(rt); |
796 | return (NULL); |
797 | |
798 | freecopy: |
799 | m_freem(mcopy); |
800 | /* Release extra ref */ |
801 | RT_REMREF(rt); |
802 | return (NULL); |
803 | } |
804 | |