1/*-
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. 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 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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 * $FreeBSD: head/sys/netinet6/ip6_ipsec.c 171732 2007-08-05 16:16:15Z bz $
30 */
31
32#include "opt_ipsec.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/mac.h>
38#include <sys/malloc.h>
39#include <sys/mbuf.h>
40#include <sys/protosw.h>
41#include <sys/socket.h>
42#include <sys/socketvar.h>
43#include <sys/sysctl.h>
44
45#include <net/if.h>
46#include <net/route.h>
47
48#include <netinet/in.h>
49#include <netinet/in_systm.h>
50#include <netinet/in_var.h>
51#include <netinet/ip.h>
52#include <netinet/in_pcb.h>
53#include <netinet/ip_var.h>
54#include <netinet/ip_options.h>
55
56#include <machine/in_cksum.h>
57
58#ifdef IPSEC
59#include <netipsec/ipsec.h>
60#include <netipsec/ipsec6.h>
61#include <netipsec/xform.h>
62#include <netipsec/key.h>
63#ifdef IPSEC_DEBUG
64#include <netipsec/key_debug.h>
65#else
66#define KEYDEBUG(lev,arg)
67#endif
68#endif /*IPSEC*/
69
70#include <netinet6/ip6_ipsec.h>
71
72extern struct protosw inet6sw[];
73
74/*
75 * Check if we have to jump over firewall processing for this packet.
76 * Called from ip_input().
77 * 1 = jump over firewall, 0 = packet goes through firewall.
78 */
79int
80ip6_ipsec_filtertunnel(struct mbuf *m)
81{
82#if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
83 /*
84 * Bypass packet filtering for packets from a tunnel.
85 */
86 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
87 return 1;
88#endif
89 return 0;
90}
91
92/*
93 * Check if this packet has an active SA and needs to be dropped instead
94 * of forwarded.
95 * Called from ip_input().
96 * 1 = drop packet, 0 = forward packet.
97 */
98int
99ip6_ipsec_fwd(struct mbuf *m)
100{
101#ifdef IPSEC
102 struct m_tag *mtag;
103 struct tdb_ident *tdbi;
104 struct secpolicy *sp;
105 int s, error;
106 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
107 s = splnet();
108 if (mtag != NULL) {
109 tdbi = (struct tdb_ident *)(mtag + 1);
110 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
111 } else {
112 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
113 IP_FORWARDING, &error);
114 }
115 if (sp == NULL) { /* NB: can happen if error */
116 splx(s);
117 /*XXX error stat???*/
118 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
119 return 1;
120 }
121
122 /*
123 * Check security policy against packet attributes.
124 */
125 error = ipsec_in_reject(sp, m);
126 KEY_FREESP(&sp);
127 splx(s);
128 if (error) {
129 ipstat.ips_cantforward++;
130 return 1;
131 }
132#endif /* IPSEC */
133 return 0;
134}
135
136/*
137 * Check if protocol type doesn't have a further header and do IPSEC
138 * decryption or reject right now. Protocols with further headers get
139 * their IPSEC treatment within the protocol specific processing.
140 * Called from ip_input().
141 * 1 = drop packet, 0 = continue processing packet.
142 */
143int
144ip6_ipsec_input(struct mbuf *m, int nxt)
145{
146#ifdef IPSEC
147 struct m_tag *mtag;
148 struct tdb_ident *tdbi;
149 struct secpolicy *sp;
150 int s, error;
151 /*
152 * enforce IPsec policy checking if we are seeing last header.
153 * note that we do not visit this with protocols with pcb layer
154 * code - like udp/tcp/raw ip.
155 */
156 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
157 ipsec6_in_reject(m, NULL)) {
158
159 /*
160 * Check if the packet has already had IPsec processing
161 * done. If so, then just pass it along. This tag gets
162 * set during AH, ESP, etc. input handling, before the
163 * packet is returned to the ip input queue for delivery.
164 */
165 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
166 s = splnet();
167 if (mtag != NULL) {
168 tdbi = (struct tdb_ident *)(mtag + 1);
169 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
170 } else {
171 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
172 IP_FORWARDING, &error);
173 }
174 if (sp != NULL) {
175 /*
176 * Check security policy against packet attributes.
177 */
178 error = ipsec_in_reject(sp, m);
179 KEY_FREESP(&sp);
180 } else {
181 /* XXX error stat??? */
182 error = EINVAL;
183 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
184 return 1;
185 }
186 splx(s);
187 if (error)
188 return 1;
189 }
190#endif /* IPSEC */
191 return 0;
192}
193
194/*
195 * Called from ip6_output().
196 * 1 = drop packet, 0 = continue processing packet,
197 * -1 = packet was reinjected and stop processing packet
198 */
199
200int
201ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
202 struct ifnet **ifp, struct secpolicy **sp)
203{
204#ifdef IPSEC
205 struct tdb_ident *tdbi;
206 struct m_tag *mtag;
207 /* XXX int s; */
208 if (sp == NULL)
209 return 1;
210 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
211 if (mtag != NULL) {
212 tdbi = (struct tdb_ident *)(mtag + 1);
213 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
214 if (*sp == NULL)
215 *error = -EINVAL; /* force silent drop */
216 m_tag_delete(*m, mtag);
217 } else {
218 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
219 error, inp);
220 }
221
222 /*
223 * There are four return cases:
224 * sp != NULL apply IPsec policy
225 * sp == NULL, error == 0 no IPsec handling needed
226 * sp == NULL, error == -EINVAL discard packet w/o error
227 * sp == NULL, error != 0 discard packet, report error
228 */
229 if (*sp != NULL) {
230 /* Loop detection, check if ipsec processing already done */
231 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request"));
232 for (mtag = m_tag_first(*m); mtag != NULL;
233 mtag = m_tag_next(*m, mtag)) {
234 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
235 continue;
236 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
237 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
238 continue;
239 /*
240 * Check if policy has an SA associated with it.
241 * This can happen when an SP has yet to acquire
242 * an SA; e.g. on first reference. If it occurs,
243 * then we let ipsec4_process_packet do its thing.
244 */
245 if ((*sp)->req->sav == NULL)
246 break;
247 tdbi = (struct tdb_ident *)(mtag + 1);
248 if (tdbi->spi == (*sp)->req->sav->spi &&
249 tdbi->proto == (*sp)->req->sav->sah->saidx.proto &&
250 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst,
251 sizeof (union sockaddr_union)) == 0) {
252 /*
253 * No IPsec processing is needed, free
254 * reference to SP.
255 *
256 * NB: null pointer to avoid free at
257 * done: below.
258 */
259 KEY_FREESP(sp), sp = NULL;
260 /* XXX splx(s); */
261 goto done;
262 }
263 }
264
265 /*
266 * Do delayed checksums now because we send before
267 * this is done in the normal processing path.
268 */
269 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
270 in_delayed_cksum(*m);
271 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
272 }
273
274 /*
275 * Preserve KAME behaviour: ENOENT can be returned
276 * when an SA acquire is in progress. Don't propagate
277 * this to user-level; it confuses applications.
278 *
279 * XXX this will go away when the SADB is redone.
280 */
281 if (*error == ENOENT)
282 *error = 0;
283 goto do_ipsec;
284 } else { /* sp == NULL */
285 if (*error != 0) {
286 /*
287 * Hack: -EINVAL is used to signal that a packet
288 * should be silently discarded. This is typically
289 * because we asked key management for an SA and
290 * it was delayed (e.g. kicked up to IKE).
291 */
292 if (*error == -EINVAL)
293 *error = 0;
294 goto bad;
295 } else {
296 /* No IPsec processing for this packet. */
297 }
298 }
299done:
300 if (sp != NULL)
301 if (*sp != NULL)
302 KEY_FREESP(sp);
303 return 0;
304do_ipsec:
305 return -1;
306bad:
307 if (sp != NULL)
308 if (*sp != NULL)
309 KEY_FREESP(sp);
310 return 1;
311#endif /* IPSEC */
312 return 0;
313}
314
315/*
316 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
317 * Called from ip_forward().
318 * Returns MTU suggestion for ICMP needfrag reply.
319 */
320int
321ip6_ipsec_mtu(struct mbuf *m)
322{
323 int mtu = 0;
324 /*
325 * If the packet is routed over IPsec tunnel, tell the
326 * originator the tunnel MTU.
327 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
328 * XXX quickhack!!!
329 */
330 struct secpolicy *sp = NULL;
331 int ipsecerror;
332 int ipsechdr;
333 struct route *ro;
334#ifdef IPSEC
335 sp = ipsec_getpolicybyaddr(m,
336 IPSEC_DIR_OUTBOUND,
337 IP_FORWARDING,
338 &ipsecerror);
339#endif /* IPSEC */
340 if (sp != NULL) {
341 /* count IPsec header size */
342 ipsechdr = ipsec4_hdrsiz(m,
343 IPSEC_DIR_OUTBOUND,
344 NULL);
345
346 /*
347 * find the correct route for outer IPv4
348 * header, compute tunnel MTU.
349 */
350 if (sp->req != NULL &&
351 sp->req->sav != NULL &&
352 sp->req->sav->sah != NULL) {
353 ro = &sp->req->sav->sah->sa_route;
354 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
355 mtu =
356 ro->ro_rt->rt_rmx.rmx_mtu ?
357 ro->ro_rt->rt_rmx.rmx_mtu :
358 ro->ro_rt->rt_ifp->if_mtu;
359 mtu -= ipsechdr;
360 }
361 }
362#ifdef IPSEC
363 KEY_FREESP(&sp);
364#endif /* IPSEC */
365 }
366 return mtu;
367}
368
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. 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 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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 * $FreeBSD: head/sys/netinet6/ip6_ipsec.c 171732 2007-08-05 16:16:15Z bz $
30 */
31
32#include "opt_ipsec.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/kernel.h>
37#include <sys/mac.h>
38#include <sys/malloc.h>
39#include <sys/mbuf.h>
40#include <sys/protosw.h>
41#include <sys/socket.h>
42#include <sys/socketvar.h>
43#include <sys/sysctl.h>
44
45#include <net/if.h>
46#include <net/route.h>
47
48#include <netinet/in.h>
49#include <netinet/in_systm.h>
50#include <netinet/in_var.h>
51#include <netinet/ip.h>
52#include <netinet/in_pcb.h>
53#include <netinet/ip_var.h>
54#include <netinet/ip_options.h>
55
56#include <machine/in_cksum.h>
57
58#ifdef IPSEC
59#include <netipsec/ipsec.h>
60#include <netipsec/ipsec6.h>
61#include <netipsec/xform.h>
62#include <netipsec/key.h>
63#ifdef IPSEC_DEBUG
64#include <netipsec/key_debug.h>
65#else
66#define KEYDEBUG(lev,arg)
67#endif
68#endif /*IPSEC*/
69
70#include <netinet6/ip6_ipsec.h>
71
72extern struct protosw inet6sw[];
73
74/*
75 * Check if we have to jump over firewall processing for this packet.
76 * Called from ip_input().
77 * 1 = jump over firewall, 0 = packet goes through firewall.
78 */
79int
80ip6_ipsec_filtertunnel(struct mbuf *m)
81{
82#if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
83 /*
84 * Bypass packet filtering for packets from a tunnel.
85 */
86 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
87 return 1;
88#endif
89 return 0;
90}
91
92/*
93 * Check if this packet has an active SA and needs to be dropped instead
94 * of forwarded.
95 * Called from ip_input().
96 * 1 = drop packet, 0 = forward packet.
97 */
98int
99ip6_ipsec_fwd(struct mbuf *m)
100{
101#ifdef IPSEC
102 struct m_tag *mtag;
103 struct tdb_ident *tdbi;
104 struct secpolicy *sp;
105 int s, error;
106 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
107 s = splnet();
108 if (mtag != NULL) {
109 tdbi = (struct tdb_ident *)(mtag + 1);
110 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
111 } else {
112 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
113 IP_FORWARDING, &error);
114 }
115 if (sp == NULL) { /* NB: can happen if error */
116 splx(s);
117 /*XXX error stat???*/
118 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
119 return 1;
120 }
121
122 /*
123 * Check security policy against packet attributes.
124 */
125 error = ipsec_in_reject(sp, m);
126 KEY_FREESP(&sp);
127 splx(s);
128 if (error) {
129 ipstat.ips_cantforward++;
130 return 1;
131 }
132#endif /* IPSEC */
133 return 0;
134}
135
136/*
137 * Check if protocol type doesn't have a further header and do IPSEC
138 * decryption or reject right now. Protocols with further headers get
139 * their IPSEC treatment within the protocol specific processing.
140 * Called from ip_input().
141 * 1 = drop packet, 0 = continue processing packet.
142 */
143int
144ip6_ipsec_input(struct mbuf *m, int nxt)
145{
146#ifdef IPSEC
147 struct m_tag *mtag;
148 struct tdb_ident *tdbi;
149 struct secpolicy *sp;
150 int s, error;
151 /*
152 * enforce IPsec policy checking if we are seeing last header.
153 * note that we do not visit this with protocols with pcb layer
154 * code - like udp/tcp/raw ip.
155 */
156 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
157 ipsec6_in_reject(m, NULL)) {
158
159 /*
160 * Check if the packet has already had IPsec processing
161 * done. If so, then just pass it along. This tag gets
162 * set during AH, ESP, etc. input handling, before the
163 * packet is returned to the ip input queue for delivery.
164 */
165 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
166 s = splnet();
167 if (mtag != NULL) {
168 tdbi = (struct tdb_ident *)(mtag + 1);
169 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
170 } else {
171 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
172 IP_FORWARDING, &error);
173 }
174 if (sp != NULL) {
175 /*
176 * Check security policy against packet attributes.
177 */
178 error = ipsec_in_reject(sp, m);
179 KEY_FREESP(&sp);
180 } else {
181 /* XXX error stat??? */
182 error = EINVAL;
183 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
184 return 1;
185 }
186 splx(s);
187 if (error)
188 return 1;
189 }
190#endif /* IPSEC */
191 return 0;
192}
193
194/*
195 * Called from ip6_output().
196 * 1 = drop packet, 0 = continue processing packet,
197 * -1 = packet was reinjected and stop processing packet
198 */
199
200int
201ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
202 struct ifnet **ifp, struct secpolicy **sp)
203{
204#ifdef IPSEC
205 struct tdb_ident *tdbi;
206 struct m_tag *mtag;
207 /* XXX int s; */
208 if (sp == NULL)
209 return 1;
210 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
211 if (mtag != NULL) {
212 tdbi = (struct tdb_ident *)(mtag + 1);
213 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
214 if (*sp == NULL)
215 *error = -EINVAL; /* force silent drop */
216 m_tag_delete(*m, mtag);
217 } else {
218 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
219 error, inp);
220 }
221
222 /*
223 * There are four return cases:
224 * sp != NULL apply IPsec policy
225 * sp == NULL, error == 0 no IPsec handling needed
226 * sp == NULL, error == -EINVAL discard packet w/o error
227 * sp == NULL, error != 0 discard packet, report error
228 */
229 if (*sp != NULL) {
230 /* Loop detection, check if ipsec processing already done */
231 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request"));
232 for (mtag = m_tag_first(*m); mtag != NULL;
233 mtag = m_tag_next(*m, mtag)) {
234 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
235 continue;
236 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
237 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
238 continue;
239 /*
240 * Check if policy has an SA associated with it.
241 * This can happen when an SP has yet to acquire
242 * an SA; e.g. on first reference. If it occurs,
243 * then we let ipsec4_process_packet do its thing.
244 */
245 if ((*sp)->req->sav == NULL)
246 break;
247 tdbi = (struct tdb_ident *)(mtag + 1);
248 if (tdbi->spi == (*sp)->req->sav->spi &&
249 tdbi->proto == (*sp)->req->sav->sah->saidx.proto &&
250 bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst,
251 sizeof (union sockaddr_union)) == 0) {
252 /*
253 * No IPsec processing is needed, free
254 * reference to SP.
255 *
256 * NB: null pointer to avoid free at
257 * done: below.
258 */
259 KEY_FREESP(sp), sp = NULL;
260 /* XXX splx(s); */
261 goto done;
262 }
263 }
264
265 /*
266 * Do delayed checksums now because we send before
267 * this is done in the normal processing path.
268 */
269 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
270 in_delayed_cksum(*m);
271 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
272 }
273
274 /*
275 * Preserve KAME behaviour: ENOENT can be returned
276 * when an SA acquire is in progress. Don't propagate
277 * this to user-level; it confuses applications.
278 *
279 * XXX this will go away when the SADB is redone.
280 */
281 if (*error == ENOENT)
282 *error = 0;
283 goto do_ipsec;
284 } else { /* sp == NULL */
285 if (*error != 0) {
286 /*
287 * Hack: -EINVAL is used to signal that a packet
288 * should be silently discarded. This is typically
289 * because we asked key management for an SA and
290 * it was delayed (e.g. kicked up to IKE).
291 */
292 if (*error == -EINVAL)
293 *error = 0;
294 goto bad;
295 } else {
296 /* No IPsec processing for this packet. */
297 }
298 }
299done:
300 if (sp != NULL)
301 if (*sp != NULL)
302 KEY_FREESP(sp);
303 return 0;
304do_ipsec:
305 return -1;
306bad:
307 if (sp != NULL)
308 if (*sp != NULL)
309 KEY_FREESP(sp);
310 return 1;
311#endif /* IPSEC */
312 return 0;
313}
314
315/*
316 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
317 * Called from ip_forward().
318 * Returns MTU suggestion for ICMP needfrag reply.
319 */
320int
321ip6_ipsec_mtu(struct mbuf *m)
322{
323 int mtu = 0;
324 /*
325 * If the packet is routed over IPsec tunnel, tell the
326 * originator the tunnel MTU.
327 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
328 * XXX quickhack!!!
329 */
330 struct secpolicy *sp = NULL;
331 int ipsecerror;
332 int ipsechdr;
333 struct route *ro;
334#ifdef IPSEC
335 sp = ipsec_getpolicybyaddr(m,
336 IPSEC_DIR_OUTBOUND,
337 IP_FORWARDING,
338 &ipsecerror);
339#endif /* IPSEC */
340 if (sp != NULL) {
341 /* count IPsec header size */
342 ipsechdr = ipsec4_hdrsiz(m,
343 IPSEC_DIR_OUTBOUND,
344 NULL);
345
346 /*
347 * find the correct route for outer IPv4
348 * header, compute tunnel MTU.
349 */
350 if (sp->req != NULL &&
351 sp->req->sav != NULL &&
352 sp->req->sav->sah != NULL) {
353 ro = &sp->req->sav->sah->sa_route;
354 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
355 mtu =
356 ro->ro_rt->rt_rmx.rmx_mtu ?
357 ro->ro_rt->rt_rmx.rmx_mtu :
358 ro->ro_rt->rt_ifp->if_mtu;
359 mtu -= ipsechdr;
360 }
361 }
362#ifdef IPSEC
363 KEY_FREESP(&sp);
364#endif /* IPSEC */
365 }
366 return mtu;
367}
368