2/* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include "opt_ip6fw.h"
34#include "opt_inet.h"
35#include "opt_inet6.h"
36#include "opt_ipsec.h"
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/malloc.h>
41#include <sys/mbuf.h>
42#include <sys/domain.h>
43#include <sys/protosw.h>
44#include <sys/socket.h>
45#include <sys/errno.h>
46#include <sys/time.h>
47#include <sys/kernel.h>
48#include <sys/syslog.h>
49
50#include <net/if.h>
51#include <net/route.h>
52#include <net/pfil.h>
53
54#include <netinet/in.h>
55#include <netinet/in_var.h>
56#include <netinet/in_systm.h>
57#include <netinet/ip.h>
58#include <netinet/ip_var.h>
59#include <netinet6/in6_var.h>
60#include <netinet/ip6.h>
61#include <netinet6/ip6_var.h>
62#include <netinet/icmp6.h>
63#include <netinet6/nd6.h>
64
65#include <netinet/in_pcb.h>
66
67#ifdef IPSEC
68#include <netinet6/ipsec.h>
69#ifdef INET6
70#include <netinet6/ipsec6.h>
71#endif
72#include <netkey/key.h>
73#endif /* IPSEC */
74
75#ifdef FAST_IPSEC
76#include <netipsec/ipsec.h>
77#include <netipsec/ipsec6.h>
78#include <netipsec/key.h>
79#define IPSEC
80#endif /* FAST_IPSEC */
81
82#include <netinet6/ip6_fw.h>
83
84#include <net/net_osdep.h>
85
86#include <netinet6/ip6protosw.h>
87
88struct route_in6 ip6_forward_rt;
89
90/*
91 * Forward a packet. If some error occurs return the sender
92 * an icmp packet. Note we can't always generate a meaningful
93 * icmp message because icmp doesn't have a large enough repertoire
94 * of codes and types.
95 *
96 * If not forwarding, just drop the packet. This could be confusing
97 * if ipforwarding was zero but some routing protocol was advancing
98 * us as a gateway to somewhere. However, we must let the routing
99 * protocol deal with that.
100 *
101 */
102
103void
104ip6_forward(m, srcrt)
105 struct mbuf *m;
106 int srcrt;
107{
108 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
109 struct sockaddr_in6 *dst = NULL;
110 struct rtentry *rt = NULL;
111 int error, type = 0, code = 0;
112 struct mbuf *mcopy = NULL;
113 struct ifnet *origifp; /* maybe unnecessary */
114 u_int32_t srczone, dstzone;
115#ifdef IPSEC
116 struct secpolicy *sp = NULL;
117 int ipsecrt = 0;
118#endif
119
120#ifdef IPSEC
121 /*
122 * Check AH/ESP integrity.
123 */
124 /*
125 * Don't increment ip6s_cantforward because this is the check
126 * before forwarding packet actually.
127 */
128 if (ipsec6_in_reject(m, NULL)) {
129#if !defined(FAST_IPSEC)
130 ipsec6stat.in_polvio++;
131#endif
132 m_freem(m);
133 return;
134 }
135#endif /* IPSEC */
136
137 /*
138 * Do not forward packets to multicast destination (should be handled
139 * by ip6_mforward().
140 * Do not forward packets with unspecified source. It was discussed
141 * in July 2000, on the ipngwg mailing list.
142 */
143 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
144 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
145 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
146 ip6stat.ip6s_cantforward++;
147 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
148 if (ip6_log_time + ip6_log_interval < time_second) {
149 ip6_log_time = time_second;
150 log(LOG_DEBUG,
151 "cannot forward "
152 "from %s to %s nxt %d received on %s\n",
153 ip6_sprintf(&ip6->ip6_src),
154 ip6_sprintf(&ip6->ip6_dst),
155 ip6->ip6_nxt,
156 if_name(m->m_pkthdr.rcvif));
157 }
158 m_freem(m);
159 return;
160 }
161
162 if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
163 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
164 icmp6_error(m, ICMP6_TIME_EXCEEDED,
165 ICMP6_TIME_EXCEED_TRANSIT, 0);
166 return;
167 }
168 ip6->ip6_hlim -= IPV6_HLIMDEC;
169
170 /*
171 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
172 * size of IPv6 + ICMPv6 headers) bytes of the packet in case
173 * we need to generate an ICMP6 message to the src.
174 * Thanks to M_EXT, in most cases copy will not occur.
175 *
176 * It is important to save it before IPsec processing as IPsec
177 * processing may modify the mbuf.
178 */
179 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
180
181#ifdef IPSEC
182 /* get a security policy for this packet */
183 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
184 IP_FORWARDING, &error);
185 if (sp == NULL) {
186 ipsec6stat.out_inval++;
187 ip6stat.ip6s_cantforward++;
188 if (mcopy) {
189#if 0
190 /* XXX: what icmp ? */
191#else
192 m_freem(mcopy);
193#endif
194 }
195 m_freem(m);
196 return;
197 }
198
199 error = 0;
200
201 /* check policy */
202 switch (sp->policy) {
203 case IPSEC_POLICY_DISCARD:
204 /*
205 * This packet is just discarded.
206 */
207 ipsec6stat.out_polvio++;
208 ip6stat.ip6s_cantforward++;
209 key_freesp(sp);
210 if (mcopy) {
211#if 0
212 /* XXX: what icmp ? */
213#else
214 m_freem(mcopy);
215#endif
216 }
217 m_freem(m);
218 return;
219
220 case IPSEC_POLICY_BYPASS:
221 case IPSEC_POLICY_NONE:
222 /* no need to do IPsec. */
223 key_freesp(sp);
224 goto skip_ipsec;
225
226 case IPSEC_POLICY_IPSEC:
227 if (sp->req == NULL) {
228 /* XXX should be panic ? */
229 printf("ip6_forward: No IPsec request specified.\n");
230 ip6stat.ip6s_cantforward++;
231 key_freesp(sp);
232 if (mcopy) {
233#if 0
234 /* XXX: what icmp ? */
235#else
236 m_freem(mcopy);
237#endif
238 }
239 m_freem(m);
240 return;
241 }
242 /* do IPsec */
243 break;
244
245 case IPSEC_POLICY_ENTRUST:
246 default:
247 /* should be panic ?? */
248 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
249 key_freesp(sp);
250 goto skip_ipsec;
251 }
252
253 {
254 struct ipsecrequest *isr = NULL;
255 struct ipsec_output_state state;
256
257 /*
258 * when the kernel forwards a packet, it is not proper to apply
259 * IPsec transport mode to the packet is not proper. this check
260 * avoid from this.
261 * at present, if there is even a transport mode SA request in the
262 * security policy, the kernel does not apply IPsec to the packet.
263 * this check is not enough because the following case is valid.
264 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
265 */
266 for (isr = sp->req; isr; isr = isr->next) {
267 if (isr->saidx.mode == IPSEC_MODE_ANY)
268 goto doipsectunnel;
269 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
270 goto doipsectunnel;
271 }
272
273 /*
274 * if there's no need for tunnel mode IPsec, skip.
275 */
276 if (!isr)
277 goto skip_ipsec;
278
279 doipsectunnel:
280 /*
281 * All the extension headers will become inaccessible
282 * (since they can be encrypted).
283 * Don't panic, we need no more updates to extension headers
284 * on inner IPv6 packet (since they are now encapsulated).
285 *
286 * IPv6 [ESP|AH] IPv6 [extension headers] payload
287 */
288 bzero(&state, sizeof(state));
289 state.m = m;
290 state.ro = NULL; /* update at ipsec6_output_tunnel() */
291 state.dst = NULL; /* update at ipsec6_output_tunnel() */
292
293 error = ipsec6_output_tunnel(&state, sp, 0);
294
295 m = state.m;
296 key_freesp(sp);
297
298 if (error) {
299 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
300 switch (error) {
301 case EHOSTUNREACH:
302 case ENETUNREACH:
303 case EMSGSIZE:
304 case ENOBUFS:
305 case ENOMEM:
306 break;
307 default:
308 printf("ip6_output (ipsec): error code %d\n", error);
309 /* FALLTHROUGH */
310 case ENOENT:
311 /* don't show these error codes to the user */
312 break;
313 }
314 ip6stat.ip6s_cantforward++;
315 if (mcopy) {
316#if 0
317 /* XXX: what icmp ? */
318#else
319 m_freem(mcopy);
320#endif
321 }
322 m_freem(m);
323 return;
324 }
325
326 if (ip6 != mtod(m, struct ip6_hdr *)) {
327 /*
328 * now tunnel mode headers are added. we are originating
329 * packet instead of forwarding the packet.
330 */
331 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL,
332 NULL);
333 goto freecopy;
334 }
335
336 /* adjust pointer */
337 dst = (struct sockaddr_in6 *)state.dst;
338 rt = state.ro ? state.ro->ro_rt : NULL;
339 if (dst != NULL && rt != NULL)
340 ipsecrt = 1;
341 }
342 skip_ipsec:
343#endif /* IPSEC */
344
345#ifdef IPSEC
346 if (ipsecrt)
347 goto skip_routing;
348#endif
349
350 dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
351 if (!srcrt) {
352 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */
353 if (ip6_forward_rt.ro_rt == 0 ||
354 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) {
355 if (ip6_forward_rt.ro_rt) {
356 RTFREE(ip6_forward_rt.ro_rt);
357 ip6_forward_rt.ro_rt = 0;
358 }
359
360 /* this probably fails but give it a try again */
361 rtalloc((struct route *)&ip6_forward_rt);
362 }
363
364 if (ip6_forward_rt.ro_rt == 0) {
365 ip6stat.ip6s_noroute++;
366 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
367 if (mcopy) {
368 icmp6_error(mcopy, ICMP6_DST_UNREACH,
369 ICMP6_DST_UNREACH_NOROUTE, 0);
370 }
371 m_freem(m);
372 return;
373 }
374 } else if ((rt = ip6_forward_rt.ro_rt) == 0 ||
375 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) {
376 if (ip6_forward_rt.ro_rt) {
377 RTFREE(ip6_forward_rt.ro_rt);
378 ip6_forward_rt.ro_rt = 0;
379 }
380 bzero(dst, sizeof(*dst));
381 dst->sin6_len = sizeof(struct sockaddr_in6);
382 dst->sin6_family = AF_INET6;
383 dst->sin6_addr = ip6->ip6_dst;
384
385 rtalloc((struct route *)&ip6_forward_rt);
386 if (ip6_forward_rt.ro_rt == 0) {
387 ip6stat.ip6s_noroute++;
388 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
389 if (mcopy) {
390 icmp6_error(mcopy, ICMP6_DST_UNREACH,
391 ICMP6_DST_UNREACH_NOROUTE, 0);
392 }
393 m_freem(m);
394 return;
395 }
396 }
397 rt = ip6_forward_rt.ro_rt;
398#ifdef IPSEC
399 skip_routing:;
400#endif
401
402 /*
403 * Scope check: if a packet can't be delivered to its destination
404 * for the reason that the destination is beyond the scope of the
405 * source address, discard the packet and return an icmp6 destination
406 * unreachable error with Code 2 (beyond scope of source address).
407 * [draft-ietf-ipngwg-icmp-v3-02.txt, Section 3.1]
408 */
409 if (in6_addr2zoneid(m->m_pkthdr.rcvif, &ip6->ip6_src, &srczone) ||
410 in6_addr2zoneid(rt->rt_ifp, &ip6->ip6_src, &dstzone)) {
411 /* XXX: this should not happen */
412 ip6stat.ip6s_cantforward++;
413 ip6stat.ip6s_badscope++;
414 m_freem(m);
415 return;
416 }
417 if (srczone != dstzone
418#ifdef IPSEC
419 && !ipsecrt
420#endif
421 ) {
422 ip6stat.ip6s_cantforward++;
423 ip6stat.ip6s_badscope++;
424 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
425
426 if (ip6_log_time + ip6_log_interval < time_second) {
427 ip6_log_time = time_second;
428 log(LOG_DEBUG,
429 "cannot forward "
430 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
431 ip6_sprintf(&ip6->ip6_src),
432 ip6_sprintf(&ip6->ip6_dst),
433 ip6->ip6_nxt,
434 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
435 }
436 if (mcopy)
437 icmp6_error(mcopy, ICMP6_DST_UNREACH,
438 ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
439 m_freem(m);
440 return;
441 }
442
443 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
444 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
445 if (mcopy) {
446 u_long mtu;
447#ifdef IPSEC
448 struct secpolicy *sp;
449 int ipsecerror;
450 size_t ipsechdrsiz;
451#endif
452
453 mtu = IN6_LINKMTU(rt->rt_ifp);
454#ifdef IPSEC
455 /*
456 * When we do IPsec tunnel ingress, we need to play
457 * with the link value (decrement IPsec header size
458 * from mtu value). The code is much simpler than v4
459 * case, as we have the outgoing interface for
460 * encapsulated packet as "rt->rt_ifp".
461 */
462 sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
463 IP_FORWARDING, &ipsecerror);
464 if (sp) {
465 ipsechdrsiz = ipsec6_hdrsiz(mcopy,
466 IPSEC_DIR_OUTBOUND, NULL);
467 if (ipsechdrsiz < mtu)
468 mtu -= ipsechdrsiz;
469 }
470
471 /*
472 * if mtu becomes less than minimum MTU,
473 * tell minimum MTU (and I'll need to fragment it).
474 */
475 if (mtu < IPV6_MMTU)
476 mtu = IPV6_MMTU;
477#endif
478 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
479 }
480 m_freem(m);
481 return;
482 }
483
484 if (rt->rt_flags & RTF_GATEWAY)
485 dst = (struct sockaddr_in6 *)rt->rt_gateway;
486
487 /*
488 * If we are to forward the packet using the same interface
489 * as one we got the packet from, perhaps we should send a redirect
490 * to sender to shortcut a hop.
491 * Only send redirect if source is sending directly to us,
492 * and if packet was not source routed (or has any options).
493 * Also, don't send redirect if forwarding using a route
494 * modified by a redirect.
495 */
496 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
497#ifdef IPSEC
498 !ipsecrt &&
499#endif
500 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
501 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
502 /*
503 * If the incoming interface is equal to the outgoing
504 * one, and the link attached to the interface is
505 * point-to-point, then it will be highly probable
506 * that a routing loop occurs. Thus, we immediately
507 * drop the packet and send an ICMPv6 error message.
508 *
509 * type/code is based on suggestion by Rich Draves.
510 * not sure if it is the best pick.
511 */
512 icmp6_error(mcopy, ICMP6_DST_UNREACH,
513 ICMP6_DST_UNREACH_ADDR, 0);
514 m_freem(m);
515 return;
516 }
517 type = ND_REDIRECT;
518 }
519
520 /*
521 * Check with the firewall...
522 */
523 if (ip6_fw_enable && ip6_fw_chk_ptr) {
524 u_short port = 0;
525 /* If ipfw says divert, we have to just drop packet */
526 if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) {
527 m_freem(m);
528 goto freecopy;
529 }
530 if (!m)
531 goto freecopy;
532 }
533
534 /*
535 * Fake scoped addresses. Note that even link-local source or
536 * destinaion can appear, if the originating node just sends the
537 * packet to us (without address resolution for the destination).
538 * Since both icmp6_error and icmp6_redirect_output fill the embedded
539 * link identifiers, we can do this stuff after making a copy for
540 * returning an error.
541 */
542 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
543 /*
544 * See corresponding comments in ip6_output.
545 * XXX: but is it possible that ip6_forward() sends a packet
546 * to a loopback interface? I don't think so, and thus
547 * I bark here. (jinmei@kame.net)
548 * XXX: it is common to route invalid packets to loopback.
549 * also, the codepath will be visited on use of ::1 in
550 * rthdr. (itojun)
551 */
552#if 1
553 if (0)
554#else
555 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
556#endif
557 {
558 printf("ip6_forward: outgoing interface is loopback. "
559 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
560 ip6_sprintf(&ip6->ip6_src),
561 ip6_sprintf(&ip6->ip6_dst),
562 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
563 if_name(rt->rt_ifp));
564 }
565
566 /* we can just use rcvif in forwarding. */
567 origifp = m->m_pkthdr.rcvif;
568 }
569 else
570 origifp = rt->rt_ifp;
571 /*
572 * clear embedded scope identifiers if necessary.
573 * in6_clearscope will touch the addresses only when necessary.
574 */
575 in6_clearscope(&ip6->ip6_src);
576 in6_clearscope(&ip6->ip6_dst);
577
578 /* Jump over all PFIL processing if hooks are not active. */
579 if (inet6_pfil_hook.ph_busy_count == -1)
580 goto pass;
581
582 /* Run through list of hooks for output packets. */
| 2/* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include "opt_ip6fw.h"
34#include "opt_inet.h"
35#include "opt_inet6.h"
36#include "opt_ipsec.h"
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/malloc.h>
41#include <sys/mbuf.h>
42#include <sys/domain.h>
43#include <sys/protosw.h>
44#include <sys/socket.h>
45#include <sys/errno.h>
46#include <sys/time.h>
47#include <sys/kernel.h>
48#include <sys/syslog.h>
49
50#include <net/if.h>
51#include <net/route.h>
52#include <net/pfil.h>
53
54#include <netinet/in.h>
55#include <netinet/in_var.h>
56#include <netinet/in_systm.h>
57#include <netinet/ip.h>
58#include <netinet/ip_var.h>
59#include <netinet6/in6_var.h>
60#include <netinet/ip6.h>
61#include <netinet6/ip6_var.h>
62#include <netinet/icmp6.h>
63#include <netinet6/nd6.h>
64
65#include <netinet/in_pcb.h>
66
67#ifdef IPSEC
68#include <netinet6/ipsec.h>
69#ifdef INET6
70#include <netinet6/ipsec6.h>
71#endif
72#include <netkey/key.h>
73#endif /* IPSEC */
74
75#ifdef FAST_IPSEC
76#include <netipsec/ipsec.h>
77#include <netipsec/ipsec6.h>
78#include <netipsec/key.h>
79#define IPSEC
80#endif /* FAST_IPSEC */
81
82#include <netinet6/ip6_fw.h>
83
84#include <net/net_osdep.h>
85
86#include <netinet6/ip6protosw.h>
87
88struct route_in6 ip6_forward_rt;
89
90/*
91 * Forward a packet. If some error occurs return the sender
92 * an icmp packet. Note we can't always generate a meaningful
93 * icmp message because icmp doesn't have a large enough repertoire
94 * of codes and types.
95 *
96 * If not forwarding, just drop the packet. This could be confusing
97 * if ipforwarding was zero but some routing protocol was advancing
98 * us as a gateway to somewhere. However, we must let the routing
99 * protocol deal with that.
100 *
101 */
102
103void
104ip6_forward(m, srcrt)
105 struct mbuf *m;
106 int srcrt;
107{
108 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
109 struct sockaddr_in6 *dst = NULL;
110 struct rtentry *rt = NULL;
111 int error, type = 0, code = 0;
112 struct mbuf *mcopy = NULL;
113 struct ifnet *origifp; /* maybe unnecessary */
114 u_int32_t srczone, dstzone;
115#ifdef IPSEC
116 struct secpolicy *sp = NULL;
117 int ipsecrt = 0;
118#endif
119
120#ifdef IPSEC
121 /*
122 * Check AH/ESP integrity.
123 */
124 /*
125 * Don't increment ip6s_cantforward because this is the check
126 * before forwarding packet actually.
127 */
128 if (ipsec6_in_reject(m, NULL)) {
129#if !defined(FAST_IPSEC)
130 ipsec6stat.in_polvio++;
131#endif
132 m_freem(m);
133 return;
134 }
135#endif /* IPSEC */
136
137 /*
138 * Do not forward packets to multicast destination (should be handled
139 * by ip6_mforward().
140 * Do not forward packets with unspecified source. It was discussed
141 * in July 2000, on the ipngwg mailing list.
142 */
143 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
144 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
145 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
146 ip6stat.ip6s_cantforward++;
147 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
148 if (ip6_log_time + ip6_log_interval < time_second) {
149 ip6_log_time = time_second;
150 log(LOG_DEBUG,
151 "cannot forward "
152 "from %s to %s nxt %d received on %s\n",
153 ip6_sprintf(&ip6->ip6_src),
154 ip6_sprintf(&ip6->ip6_dst),
155 ip6->ip6_nxt,
156 if_name(m->m_pkthdr.rcvif));
157 }
158 m_freem(m);
159 return;
160 }
161
162 if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
163 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
164 icmp6_error(m, ICMP6_TIME_EXCEEDED,
165 ICMP6_TIME_EXCEED_TRANSIT, 0);
166 return;
167 }
168 ip6->ip6_hlim -= IPV6_HLIMDEC;
169
170 /*
171 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
172 * size of IPv6 + ICMPv6 headers) bytes of the packet in case
173 * we need to generate an ICMP6 message to the src.
174 * Thanks to M_EXT, in most cases copy will not occur.
175 *
176 * It is important to save it before IPsec processing as IPsec
177 * processing may modify the mbuf.
178 */
179 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
180
181#ifdef IPSEC
182 /* get a security policy for this packet */
183 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND,
184 IP_FORWARDING, &error);
185 if (sp == NULL) {
186 ipsec6stat.out_inval++;
187 ip6stat.ip6s_cantforward++;
188 if (mcopy) {
189#if 0
190 /* XXX: what icmp ? */
191#else
192 m_freem(mcopy);
193#endif
194 }
195 m_freem(m);
196 return;
197 }
198
199 error = 0;
200
201 /* check policy */
202 switch (sp->policy) {
203 case IPSEC_POLICY_DISCARD:
204 /*
205 * This packet is just discarded.
206 */
207 ipsec6stat.out_polvio++;
208 ip6stat.ip6s_cantforward++;
209 key_freesp(sp);
210 if (mcopy) {
211#if 0
212 /* XXX: what icmp ? */
213#else
214 m_freem(mcopy);
215#endif
216 }
217 m_freem(m);
218 return;
219
220 case IPSEC_POLICY_BYPASS:
221 case IPSEC_POLICY_NONE:
222 /* no need to do IPsec. */
223 key_freesp(sp);
224 goto skip_ipsec;
225
226 case IPSEC_POLICY_IPSEC:
227 if (sp->req == NULL) {
228 /* XXX should be panic ? */
229 printf("ip6_forward: No IPsec request specified.\n");
230 ip6stat.ip6s_cantforward++;
231 key_freesp(sp);
232 if (mcopy) {
233#if 0
234 /* XXX: what icmp ? */
235#else
236 m_freem(mcopy);
237#endif
238 }
239 m_freem(m);
240 return;
241 }
242 /* do IPsec */
243 break;
244
245 case IPSEC_POLICY_ENTRUST:
246 default:
247 /* should be panic ?? */
248 printf("ip6_forward: Invalid policy found. %d\n", sp->policy);
249 key_freesp(sp);
250 goto skip_ipsec;
251 }
252
253 {
254 struct ipsecrequest *isr = NULL;
255 struct ipsec_output_state state;
256
257 /*
258 * when the kernel forwards a packet, it is not proper to apply
259 * IPsec transport mode to the packet is not proper. this check
260 * avoid from this.
261 * at present, if there is even a transport mode SA request in the
262 * security policy, the kernel does not apply IPsec to the packet.
263 * this check is not enough because the following case is valid.
264 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require;
265 */
266 for (isr = sp->req; isr; isr = isr->next) {
267 if (isr->saidx.mode == IPSEC_MODE_ANY)
268 goto doipsectunnel;
269 if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
270 goto doipsectunnel;
271 }
272
273 /*
274 * if there's no need for tunnel mode IPsec, skip.
275 */
276 if (!isr)
277 goto skip_ipsec;
278
279 doipsectunnel:
280 /*
281 * All the extension headers will become inaccessible
282 * (since they can be encrypted).
283 * Don't panic, we need no more updates to extension headers
284 * on inner IPv6 packet (since they are now encapsulated).
285 *
286 * IPv6 [ESP|AH] IPv6 [extension headers] payload
287 */
288 bzero(&state, sizeof(state));
289 state.m = m;
290 state.ro = NULL; /* update at ipsec6_output_tunnel() */
291 state.dst = NULL; /* update at ipsec6_output_tunnel() */
292
293 error = ipsec6_output_tunnel(&state, sp, 0);
294
295 m = state.m;
296 key_freesp(sp);
297
298 if (error) {
299 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
300 switch (error) {
301 case EHOSTUNREACH:
302 case ENETUNREACH:
303 case EMSGSIZE:
304 case ENOBUFS:
305 case ENOMEM:
306 break;
307 default:
308 printf("ip6_output (ipsec): error code %d\n", error);
309 /* FALLTHROUGH */
310 case ENOENT:
311 /* don't show these error codes to the user */
312 break;
313 }
314 ip6stat.ip6s_cantforward++;
315 if (mcopy) {
316#if 0
317 /* XXX: what icmp ? */
318#else
319 m_freem(mcopy);
320#endif
321 }
322 m_freem(m);
323 return;
324 }
325
326 if (ip6 != mtod(m, struct ip6_hdr *)) {
327 /*
328 * now tunnel mode headers are added. we are originating
329 * packet instead of forwarding the packet.
330 */
331 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL,
332 NULL);
333 goto freecopy;
334 }
335
336 /* adjust pointer */
337 dst = (struct sockaddr_in6 *)state.dst;
338 rt = state.ro ? state.ro->ro_rt : NULL;
339 if (dst != NULL && rt != NULL)
340 ipsecrt = 1;
341 }
342 skip_ipsec:
343#endif /* IPSEC */
344
345#ifdef IPSEC
346 if (ipsecrt)
347 goto skip_routing;
348#endif
349
350 dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst;
351 if (!srcrt) {
352 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */
353 if (ip6_forward_rt.ro_rt == 0 ||
354 (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) {
355 if (ip6_forward_rt.ro_rt) {
356 RTFREE(ip6_forward_rt.ro_rt);
357 ip6_forward_rt.ro_rt = 0;
358 }
359
360 /* this probably fails but give it a try again */
361 rtalloc((struct route *)&ip6_forward_rt);
362 }
363
364 if (ip6_forward_rt.ro_rt == 0) {
365 ip6stat.ip6s_noroute++;
366 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
367 if (mcopy) {
368 icmp6_error(mcopy, ICMP6_DST_UNREACH,
369 ICMP6_DST_UNREACH_NOROUTE, 0);
370 }
371 m_freem(m);
372 return;
373 }
374 } else if ((rt = ip6_forward_rt.ro_rt) == 0 ||
375 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) {
376 if (ip6_forward_rt.ro_rt) {
377 RTFREE(ip6_forward_rt.ro_rt);
378 ip6_forward_rt.ro_rt = 0;
379 }
380 bzero(dst, sizeof(*dst));
381 dst->sin6_len = sizeof(struct sockaddr_in6);
382 dst->sin6_family = AF_INET6;
383 dst->sin6_addr = ip6->ip6_dst;
384
385 rtalloc((struct route *)&ip6_forward_rt);
386 if (ip6_forward_rt.ro_rt == 0) {
387 ip6stat.ip6s_noroute++;
388 in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute);
389 if (mcopy) {
390 icmp6_error(mcopy, ICMP6_DST_UNREACH,
391 ICMP6_DST_UNREACH_NOROUTE, 0);
392 }
393 m_freem(m);
394 return;
395 }
396 }
397 rt = ip6_forward_rt.ro_rt;
398#ifdef IPSEC
399 skip_routing:;
400#endif
401
402 /*
403 * Scope check: if a packet can't be delivered to its destination
404 * for the reason that the destination is beyond the scope of the
405 * source address, discard the packet and return an icmp6 destination
406 * unreachable error with Code 2 (beyond scope of source address).
407 * [draft-ietf-ipngwg-icmp-v3-02.txt, Section 3.1]
408 */
409 if (in6_addr2zoneid(m->m_pkthdr.rcvif, &ip6->ip6_src, &srczone) ||
410 in6_addr2zoneid(rt->rt_ifp, &ip6->ip6_src, &dstzone)) {
411 /* XXX: this should not happen */
412 ip6stat.ip6s_cantforward++;
413 ip6stat.ip6s_badscope++;
414 m_freem(m);
415 return;
416 }
417 if (srczone != dstzone
418#ifdef IPSEC
419 && !ipsecrt
420#endif
421 ) {
422 ip6stat.ip6s_cantforward++;
423 ip6stat.ip6s_badscope++;
424 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard);
425
426 if (ip6_log_time + ip6_log_interval < time_second) {
427 ip6_log_time = time_second;
428 log(LOG_DEBUG,
429 "cannot forward "
430 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
431 ip6_sprintf(&ip6->ip6_src),
432 ip6_sprintf(&ip6->ip6_dst),
433 ip6->ip6_nxt,
434 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp));
435 }
436 if (mcopy)
437 icmp6_error(mcopy, ICMP6_DST_UNREACH,
438 ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
439 m_freem(m);
440 return;
441 }
442
443 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
444 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
445 if (mcopy) {
446 u_long mtu;
447#ifdef IPSEC
448 struct secpolicy *sp;
449 int ipsecerror;
450 size_t ipsechdrsiz;
451#endif
452
453 mtu = IN6_LINKMTU(rt->rt_ifp);
454#ifdef IPSEC
455 /*
456 * When we do IPsec tunnel ingress, we need to play
457 * with the link value (decrement IPsec header size
458 * from mtu value). The code is much simpler than v4
459 * case, as we have the outgoing interface for
460 * encapsulated packet as "rt->rt_ifp".
461 */
462 sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND,
463 IP_FORWARDING, &ipsecerror);
464 if (sp) {
465 ipsechdrsiz = ipsec6_hdrsiz(mcopy,
466 IPSEC_DIR_OUTBOUND, NULL);
467 if (ipsechdrsiz < mtu)
468 mtu -= ipsechdrsiz;
469 }
470
471 /*
472 * if mtu becomes less than minimum MTU,
473 * tell minimum MTU (and I'll need to fragment it).
474 */
475 if (mtu < IPV6_MMTU)
476 mtu = IPV6_MMTU;
477#endif
478 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
479 }
480 m_freem(m);
481 return;
482 }
483
484 if (rt->rt_flags & RTF_GATEWAY)
485 dst = (struct sockaddr_in6 *)rt->rt_gateway;
486
487 /*
488 * If we are to forward the packet using the same interface
489 * as one we got the packet from, perhaps we should send a redirect
490 * to sender to shortcut a hop.
491 * Only send redirect if source is sending directly to us,
492 * and if packet was not source routed (or has any options).
493 * Also, don't send redirect if forwarding using a route
494 * modified by a redirect.
495 */
496 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt &&
497#ifdef IPSEC
498 !ipsecrt &&
499#endif
500 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
501 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) {
502 /*
503 * If the incoming interface is equal to the outgoing
504 * one, and the link attached to the interface is
505 * point-to-point, then it will be highly probable
506 * that a routing loop occurs. Thus, we immediately
507 * drop the packet and send an ICMPv6 error message.
508 *
509 * type/code is based on suggestion by Rich Draves.
510 * not sure if it is the best pick.
511 */
512 icmp6_error(mcopy, ICMP6_DST_UNREACH,
513 ICMP6_DST_UNREACH_ADDR, 0);
514 m_freem(m);
515 return;
516 }
517 type = ND_REDIRECT;
518 }
519
520 /*
521 * Check with the firewall...
522 */
523 if (ip6_fw_enable && ip6_fw_chk_ptr) {
524 u_short port = 0;
525 /* If ipfw says divert, we have to just drop packet */
526 if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) {
527 m_freem(m);
528 goto freecopy;
529 }
530 if (!m)
531 goto freecopy;
532 }
533
534 /*
535 * Fake scoped addresses. Note that even link-local source or
536 * destinaion can appear, if the originating node just sends the
537 * packet to us (without address resolution for the destination).
538 * Since both icmp6_error and icmp6_redirect_output fill the embedded
539 * link identifiers, we can do this stuff after making a copy for
540 * returning an error.
541 */
542 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
543 /*
544 * See corresponding comments in ip6_output.
545 * XXX: but is it possible that ip6_forward() sends a packet
546 * to a loopback interface? I don't think so, and thus
547 * I bark here. (jinmei@kame.net)
548 * XXX: it is common to route invalid packets to loopback.
549 * also, the codepath will be visited on use of ::1 in
550 * rthdr. (itojun)
551 */
552#if 1
553 if (0)
554#else
555 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
556#endif
557 {
558 printf("ip6_forward: outgoing interface is loopback. "
559 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
560 ip6_sprintf(&ip6->ip6_src),
561 ip6_sprintf(&ip6->ip6_dst),
562 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
563 if_name(rt->rt_ifp));
564 }
565
566 /* we can just use rcvif in forwarding. */
567 origifp = m->m_pkthdr.rcvif;
568 }
569 else
570 origifp = rt->rt_ifp;
571 /*
572 * clear embedded scope identifiers if necessary.
573 * in6_clearscope will touch the addresses only when necessary.
574 */
575 in6_clearscope(&ip6->ip6_src);
576 in6_clearscope(&ip6->ip6_dst);
577
578 /* Jump over all PFIL processing if hooks are not active. */
579 if (inet6_pfil_hook.ph_busy_count == -1)
580 goto pass;
581
582 /* Run through list of hooks for output packets. */
|