1 /* $FreeBSD: src/sys/netinet6/ip6_forward.c,v 1.4.2.7 2003/01/24 05:11:35 sam Exp $ */
2 /* $DragonFly: src/sys/netinet6/ip6_forward.c,v 1.13 2006/12/22 23:57:53 swildner Exp $ */
3 /* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #include "opt_ip6fw.h"
36 #include "opt_inet6.h"
37 #include "opt_ipsec.h"
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/malloc.h>
43 #include <sys/domain.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/errno.h>
48 #include <sys/kernel.h>
49 #include <sys/syslog.h>
52 #include <net/route.h>
55 #include <netinet/in.h>
56 #include <netinet/in_var.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/ip.h>
59 #include <netinet/ip_var.h>
60 #include <netinet6/in6_var.h>
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet/icmp6.h>
64 #include <netinet6/nd6.h>
66 #include <netinet/in_pcb.h>
69 #include <netinet6/ipsec.h>
71 #include <netinet6/ipsec6.h>
73 #include <netproto/key/key.h>
77 #include <netproto/ipsec/ipsec.h>
78 #include <netproto/ipsec/ipsec6.h>
79 #include <netproto/ipsec/key.h>
81 #endif /* FAST_IPSEC */
83 #include <net/ip6fw/ip6_fw.h>
85 #include <net/net_osdep.h>
87 struct route_in6 ip6_forward_rt
;
90 * Forward a packet. If some error occurs return the sender
91 * an icmp packet. Note we can't always generate a meaningful
92 * icmp message because icmp doesn't have a large enough repertoire
95 * If not forwarding, just drop the packet. This could be confusing
96 * if ipforwarding was zero but some routing protocol was advancing
97 * us as a gateway to somewhere. However, we must let the routing
98 * protocol deal with that.
103 ip6_forward(struct mbuf
*m
, int srcrt
)
105 struct ip6_hdr
*ip6
= mtod(m
, struct ip6_hdr
*);
106 struct sockaddr_in6
*dst
;
108 int error
, type
= 0, code
= 0;
109 struct mbuf
*mcopy
= NULL
;
110 struct ifnet
*origifp
; /* maybe unnecessary */
111 u_int32_t srczone
, dstzone
;
113 struct secpolicy
*sp
= NULL
;
118 * Check AH/ESP integrity.
121 * Don't increment ip6s_cantforward because this is the check
122 * before forwarding packet actually.
124 if (ipsec6_in_reject(m
, NULL
)) {
125 #if !defined(FAST_IPSEC)
126 ipsec6stat
.in_polvio
++;
134 * Do not forward packets to multicast destination (should be handled
136 * Do not forward packets with unspecified source. It was discussed
137 * in July 2000, on the ipngwg mailing list.
139 if ((m
->m_flags
& (M_BCAST
| M_MCAST
)) != 0 ||
140 IN6_IS_ADDR_MULTICAST(&ip6
->ip6_dst
) ||
141 IN6_IS_ADDR_UNSPECIFIED(&ip6
->ip6_src
)) {
142 ip6stat
.ip6s_cantforward
++;
143 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
144 if (ip6_log_time
+ ip6_log_interval
< time_uptime
) {
145 ip6_log_time
= time_uptime
;
148 "from %s to %s nxt %d received on %s\n",
149 ip6_sprintf(&ip6
->ip6_src
),
150 ip6_sprintf(&ip6
->ip6_dst
),
152 if_name(m
->m_pkthdr
.rcvif
));
158 if (ip6
->ip6_hlim
<= IPV6_HLIMDEC
) {
159 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
160 icmp6_error(m
, ICMP6_TIME_EXCEEDED
,
161 ICMP6_TIME_EXCEED_TRANSIT
, 0);
164 ip6
->ip6_hlim
-= IPV6_HLIMDEC
;
167 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
168 * size of IPv6 + ICMPv6 headers) bytes of the packet in case
169 * we need to generate an ICMP6 message to the src.
170 * Thanks to M_EXT, in most cases copy will not occur.
172 * It is important to save it before IPsec processing as IPsec
173 * processing may modify the mbuf.
175 mcopy
= m_copy(m
, 0, imin(m
->m_pkthdr
.len
, ICMPV6_PLD_MAXLEN
));
178 /* get a security policy for this packet */
179 sp
= ipsec6_getpolicybyaddr(m
, IPSEC_DIR_OUTBOUND
, IP_FORWARDING
,
182 ipsec6stat
.out_inval
++;
183 ip6stat
.ip6s_cantforward
++;
186 /* XXX: what icmp ? */
198 switch (sp
->policy
) {
199 case IPSEC_POLICY_DISCARD
:
201 * This packet is just discarded.
203 ipsec6stat
.out_polvio
++;
204 ip6stat
.ip6s_cantforward
++;
208 /* XXX: what icmp ? */
216 case IPSEC_POLICY_BYPASS
:
217 case IPSEC_POLICY_NONE
:
218 /* no need to do IPsec. */
222 case IPSEC_POLICY_IPSEC
:
223 if (sp
->req
== NULL
) {
224 /* XXX should be panic ? */
225 kprintf("ip6_forward: No IPsec request specified.\n");
226 ip6stat
.ip6s_cantforward
++;
230 /* XXX: what icmp ? */
241 case IPSEC_POLICY_ENTRUST
:
243 /* should be panic ?? */
244 kprintf("ip6_forward: Invalid policy found. %d\n", sp
->policy
);
250 struct ipsec_output_state state
;
253 * All the extension headers will become inaccessible
254 * (since they can be encrypted).
255 * Don't panic, we need no more updates to extension headers
256 * on inner IPv6 packet (since they are now encapsulated).
258 * IPv6 [ESP|AH] IPv6 [extension headers] payload
260 bzero(&state
, sizeof(state
));
262 state
.ro
= NULL
; /* update at ipsec6_output_tunnel() */
263 state
.dst
= NULL
; /* update at ipsec6_output_tunnel() */
265 error
= ipsec6_output_tunnel(&state
, sp
, 0);
271 /* mbuf is already reclaimed in ipsec6_output_tunnel. */
280 kprintf("ip6_output (ipsec): error code %d\n", error
);
283 /* don't show these error codes to the user */
286 ip6stat
.ip6s_cantforward
++;
289 /* XXX: what icmp ? */
301 dst
= (struct sockaddr_in6
*)&ip6_forward_rt
.ro_dst
;
303 /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */
304 if (ip6_forward_rt
.ro_rt
== NULL
||
305 !(ip6_forward_rt
.ro_rt
->rt_flags
& RTF_UP
)) {
306 if (ip6_forward_rt
.ro_rt
) {
307 RTFREE(ip6_forward_rt
.ro_rt
);
308 ip6_forward_rt
.ro_rt
= 0;
311 /* this probably fails but give it a try again */
312 rtalloc_ign((struct route
*)&ip6_forward_rt
,
316 if (ip6_forward_rt
.ro_rt
== NULL
) {
317 ip6stat
.ip6s_noroute
++;
318 in6_ifstat_inc(m
->m_pkthdr
.rcvif
, ifs6_in_noroute
);
320 icmp6_error(mcopy
, ICMP6_DST_UNREACH
,
321 ICMP6_DST_UNREACH_NOROUTE
, 0);
326 } else if ((rt
= ip6_forward_rt
.ro_rt
) == NULL
||
327 !IN6_ARE_ADDR_EQUAL(&ip6
->ip6_dst
, &dst
->sin6_addr
)) {
328 if (ip6_forward_rt
.ro_rt
) {
329 RTFREE(ip6_forward_rt
.ro_rt
);
330 ip6_forward_rt
.ro_rt
= 0;
332 bzero(dst
, sizeof(*dst
));
333 dst
->sin6_len
= sizeof(struct sockaddr_in6
);
334 dst
->sin6_family
= AF_INET6
;
335 dst
->sin6_addr
= ip6
->ip6_dst
;
337 rtalloc_ign((struct route
*)&ip6_forward_rt
, RTF_PRCLONING
);
338 if (ip6_forward_rt
.ro_rt
== NULL
) {
339 ip6stat
.ip6s_noroute
++;
340 in6_ifstat_inc(m
->m_pkthdr
.rcvif
, ifs6_in_noroute
);
342 icmp6_error(mcopy
, ICMP6_DST_UNREACH
,
343 ICMP6_DST_UNREACH_NOROUTE
, 0);
349 rt
= ip6_forward_rt
.ro_rt
;
352 * Scope check: if a packet can't be delivered to its destination
353 * for the reason that the destination is beyond the scope of the
354 * source address, discard the packet and return an icmp6 destination
355 * unreachable error with Code 2 (beyond scope of source address).
356 * [draft-ietf-ipngwg-icmp-v3-02.txt, Section 3.1]
358 if (in6_addr2zoneid(m
->m_pkthdr
.rcvif
, &ip6
->ip6_src
, &srczone
) ||
359 in6_addr2zoneid(rt
->rt_ifp
, &ip6
->ip6_src
, &dstzone
) ||
360 srczone
!= dstzone
) {
361 ip6stat
.ip6s_cantforward
++;
362 ip6stat
.ip6s_badscope
++;
363 in6_ifstat_inc(rt
->rt_ifp
, ifs6_in_discard
);
365 if (ip6_log_time
+ ip6_log_interval
< time_uptime
) {
366 ip6_log_time
= time_uptime
;
369 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
370 ip6_sprintf(&ip6
->ip6_src
),
371 ip6_sprintf(&ip6
->ip6_dst
),
373 if_name(m
->m_pkthdr
.rcvif
), if_name(rt
->rt_ifp
));
376 icmp6_error(mcopy
, ICMP6_DST_UNREACH
,
377 ICMP6_DST_UNREACH_BEYONDSCOPE
, 0);
382 if (m
->m_pkthdr
.len
> IN6_LINKMTU(rt
->rt_ifp
)) {
383 in6_ifstat_inc(rt
->rt_ifp
, ifs6_in_toobig
);
387 struct secpolicy
*sp
;
392 mtu
= IN6_LINKMTU(rt
->rt_ifp
);
395 * When we do IPsec tunnel ingress, we need to play
396 * with if_mtu value (decrement IPsec header size
397 * from mtu value). The code is much simpler than v4
398 * case, as we have the outgoing interface for
399 * encapsulated packet as "rt->rt_ifp".
401 sp
= ipsec6_getpolicybyaddr(mcopy
, IPSEC_DIR_OUTBOUND
,
402 IP_FORWARDING
, &ipsecerror
);
404 ipsechdrsiz
= ipsec6_hdrsiz(mcopy
,
405 IPSEC_DIR_OUTBOUND
, NULL
);
406 if (ipsechdrsiz
< mtu
)
411 * if mtu becomes less than minimum MTU,
412 * tell minimum MTU (and I'll need to fragment it).
417 icmp6_error(mcopy
, ICMP6_PACKET_TOO_BIG
, 0, mtu
);
423 if (rt
->rt_flags
& RTF_GATEWAY
)
424 dst
= (struct sockaddr_in6
*)rt
->rt_gateway
;
427 * If we are to forward the packet using the same interface
428 * as one we got the packet from, perhaps we should send a redirect
429 * to sender to shortcut a hop.
430 * Only send redirect if source is sending directly to us,
431 * and if packet was not source routed (or has any options).
432 * Also, don't send redirect if forwarding using a route
433 * modified by a redirect.
435 if (rt
->rt_ifp
== m
->m_pkthdr
.rcvif
&& !srcrt
&&
436 (rt
->rt_flags
& (RTF_DYNAMIC
| RTF_MODIFIED
)) == 0) {
437 if (rt
->rt_ifp
->if_flags
& IFF_POINTOPOINT
) {
439 * If the incoming interface is equal to the outgoing
440 * one, and the link attached to the interface is
441 * point-to-point, then it will be highly probable
442 * that a routing loop occurs. Thus, we immediately
443 * drop the packet and send an ICMPv6 error message.
445 * type/code is based on suggestion by Rich Draves.
446 * not sure if it is the best pick.
448 icmp6_error(mcopy
, ICMP6_DST_UNREACH
,
449 ICMP6_DST_UNREACH_ADDR
, 0);
457 * Check with the firewall...
459 if (ip6_fw_enable
&& ip6_fw_chk_ptr
) {
461 /* If ipfw says divert, we have to just drop packet */
462 if ((*ip6_fw_chk_ptr
)(&ip6
, rt
->rt_ifp
, &port
, &m
)) {
471 * Fake scoped addresses. Note that even link-local source or
472 * destinaion can appear, if the originating node just sends the
473 * packet to us (without address resolution for the destination).
474 * Since both icmp6_error and icmp6_redirect_output fill the embedded
475 * link identifiers, we can do this stuff after making a copy for
476 * returning an error.
478 if (rt
->rt_ifp
->if_flags
& IFF_LOOPBACK
) {
480 * See corresponding comments in ip6_output.
481 * XXX: but is it possible that ip6_forward() sends a packet
482 * to a loopback interface? I don't think so, and thus
483 * I bark here. (jinmei@kame.net)
484 * XXX: it is common to route invalid packets to loopback.
485 * also, the codepath will be visited on use of ::1 in
491 if ((rt
->rt_flags
& (RTF_BLACKHOLE
| RTF_REJECT
)) == 0)
494 kprintf("ip6_forward: outgoing interface is loopback. "
495 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
496 ip6_sprintf(&ip6
->ip6_src
),
497 ip6_sprintf(&ip6
->ip6_dst
),
498 ip6
->ip6_nxt
, if_name(m
->m_pkthdr
.rcvif
),
499 if_name(rt
->rt_ifp
));
502 /* we can just use rcvif in forwarding. */
503 origifp
= m
->m_pkthdr
.rcvif
;
506 origifp
= rt
->rt_ifp
;
508 * clear embedded scope identifiers if necessary.
509 * in6_clearscope will touch the addresses only when necessary.
511 in6_clearscope(&ip6
->ip6_src
);
512 in6_clearscope(&ip6
->ip6_dst
);
515 * Run through list of hooks for output packets.
517 if (pfil_has_hooks(&inet6_pfil_hook
)) {
518 error
= pfil_run_hooks(&inet6_pfil_hook
, &m
, rt
->rt_ifp
,
524 ip6
= mtod(m
, struct ip6_hdr
*);
527 error
= nd6_output(rt
->rt_ifp
, origifp
, m
, dst
, rt
);
529 in6_ifstat_inc(rt
->rt_ifp
, ifs6_out_discard
);
530 ip6stat
.ip6s_cantforward
++;
532 ip6stat
.ip6s_forward
++;
533 in6_ifstat_inc(rt
->rt_ifp
, ifs6_out_forward
);
535 ip6stat
.ip6s_redirectsent
++;
546 if (type
== ND_REDIRECT
) {
547 icmp6_redirect_output(mcopy
, rt
);
553 /* xxx MTU is constant in PPP? */
557 /* Tell source to slow down like source quench in IP? */
560 case ENETUNREACH
: /* shouldn't happen, checked above */
565 type
= ICMP6_DST_UNREACH
;
566 code
= ICMP6_DST_UNREACH_ADDR
;
569 icmp6_error(mcopy
, type
, code
, 0);