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30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include "opt_ipsec.h"
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/errno.h>
39 #include <sys/kernel.h>
40 #include <sys/malloc.h>
42 #include <sys/protosw.h>
43 #include <sys/socket.h>
44 #include <sys/socketvar.h>
45 #include <sys/sysctl.h>
46 #include <sys/vimage.h>
49 #include <net/route.h>
51 #include <netinet/in.h>
52 #include <netinet/in_systm.h>
53 #include <netinet/in_var.h>
54 #include <netinet/ip.h>
55 #include <netinet/in_pcb.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/ip_options.h>
58 #include <netinet/ip_ipsec.h>
59 #include <netinet/vinet.h>
61 #include <netinet/sctp_crc32.h>
64 #include <machine/in_cksum.h>
67 #include <netipsec/ipsec.h>
68 #include <netipsec/xform.h>
69 #include <netipsec/key.h>
72 extern struct protosw inetsw[];
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.
80 ip_ipsec_filtertunnel(struct mbuf *m)
82 #if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
84 * Bypass packet filtering for packets from a tunnel.
86 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
93 * Check if this packet has an active SA and needs to be dropped instead
95 * Called from ip_input().
96 * 1 = drop packet, 0 = forward packet.
99 ip_ipsec_fwd(struct mbuf *m)
102 INIT_VNET_INET(curvnet);
103 INIT_VNET_IPSEC(curvnet);
105 struct tdb_ident *tdbi;
106 struct secpolicy *sp;
109 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
112 tdbi = (struct tdb_ident *)(mtag + 1);
113 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
115 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
116 IP_FORWARDING, &error);
118 if (sp == NULL) { /* NB: can happen if error */
120 /*XXX error stat???*/
121 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
126 * Check security policy against packet attributes.
128 error = ipsec_in_reject(sp, m);
132 IPSTAT_INC(ips_cantforward);
140 * Check if protocol type doesn't have a further header and do IPSEC
141 * decryption or reject right now. Protocols with further headers get
142 * their IPSEC treatment within the protocol specific processing.
143 * Called from ip_input().
144 * 1 = drop packet, 0 = continue processing packet.
147 ip_ipsec_input(struct mbuf *m)
149 struct ip *ip = mtod(m, struct ip *);
151 INIT_VNET_IPSEC(curvnet);
153 struct tdb_ident *tdbi;
154 struct secpolicy *sp;
157 * enforce IPsec policy checking if we are seeing last header.
158 * note that we do not visit this with protocols with pcb layer
159 * code - like udp/tcp/raw ip.
161 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
163 * Check if the packet has already had IPsec processing
164 * done. If so, then just pass it along. This tag gets
165 * set during AH, ESP, etc. input handling, before the
166 * packet is returned to the ip input queue for delivery.
168 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
171 tdbi = (struct tdb_ident *)(mtag + 1);
172 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
174 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
175 IP_FORWARDING, &error);
179 * Check security policy against packet attributes.
181 error = ipsec_in_reject(sp, m);
184 /* XXX error stat??? */
186 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
198 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
199 * Called from ip_forward().
200 * Returns MTU suggestion for ICMP needfrag reply.
203 ip_ipsec_mtu(struct mbuf *m, int mtu)
206 * If the packet is routed over IPsec tunnel, tell the
207 * originator the tunnel MTU.
208 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
211 struct secpolicy *sp = NULL;
215 sp = ipsec_getpolicybyaddr(m,
220 /* count IPsec header size */
221 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
224 * find the correct route for outer IPv4
225 * header, compute tunnel MTU.
227 if (sp->req != NULL &&
228 sp->req->sav != NULL &&
229 sp->req->sav->sah != NULL) {
230 ro = &sp->req->sav->sah->sa_route;
231 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
233 ro->ro_rt->rt_rmx.rmx_mtu ?
234 ro->ro_rt->rt_rmx.rmx_mtu :
235 ro->ro_rt->rt_ifp->if_mtu;
246 * Called from ip_output().
247 * 1 = drop packet, 0 = continue processing packet,
248 * -1 = packet was reinjected and stop processing packet
251 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
252 struct route **ro, struct route *iproute, struct sockaddr_in **dst,
253 struct in_ifaddr **ia, struct ifnet **ifp)
256 struct secpolicy *sp = NULL;
257 struct ip *ip = mtod(*m, struct ip *);
258 struct tdb_ident *tdbi;
262 * Check the security policy (SP) for the packet and, if
263 * required, do IPsec-related processing. There are two
264 * cases here; the first time a packet is sent through
265 * it will be untagged and handled by ipsec4_checkpolicy.
266 * If the packet is resubmitted to ip_output (e.g. after
267 * AH, ESP, etc. processing), there will be a tag to bypass
268 * the lookup and related policy checking.
270 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
273 tdbi = (struct tdb_ident *)(mtag + 1);
274 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
276 *error = -EINVAL; /* force silent drop */
277 m_tag_delete(*m, mtag);
279 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
283 * There are four return cases:
284 * sp != NULL apply IPsec policy
285 * sp == NULL, error == 0 no IPsec handling needed
286 * sp == NULL, error == -EINVAL discard packet w/o error
287 * sp == NULL, error != 0 discard packet, report error
290 /* Loop detection, check if ipsec processing already done */
291 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
292 for (mtag = m_tag_first(*m); mtag != NULL;
293 mtag = m_tag_next(*m, mtag)) {
294 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
296 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
297 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
300 * Check if policy has an SA associated with it.
301 * This can happen when an SP has yet to acquire
302 * an SA; e.g. on first reference. If it occurs,
303 * then we let ipsec4_process_packet do its thing.
305 if (sp->req->sav == NULL)
307 tdbi = (struct tdb_ident *)(mtag + 1);
308 if (tdbi->spi == sp->req->sav->spi &&
309 tdbi->proto == sp->req->sav->sah->saidx.proto &&
310 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
311 sizeof (union sockaddr_union)) == 0) {
313 * No IPsec processing is needed, free
316 * NB: null pointer to avoid free at
319 KEY_FREESP(&sp), sp = NULL;
326 * Do delayed checksums now because we send before
327 * this is done in the normal processing path.
329 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
330 in_delayed_cksum(*m);
331 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
334 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
335 sctp_delayed_cksum(*m);
336 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
339 ip->ip_len = htons(ip->ip_len);
340 ip->ip_off = htons(ip->ip_off);
342 /* NB: callee frees mbuf */
343 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
344 if (*error == EJUSTRETURN) {
346 * We had a SP with a level of 'use' and no SA. We
347 * will just continue to process the packet without
348 * IPsec processing and return without error.
351 ip->ip_len = ntohs(ip->ip_len);
352 ip->ip_off = ntohs(ip->ip_off);
356 * Preserve KAME behaviour: ENOENT can be returned
357 * when an SA acquire is in progress. Don't propagate
358 * this to user-level; it confuses applications.
360 * XXX this will go away when the SADB is redone.
362 if (*error == ENOENT)
366 } else { /* sp == NULL */
371 * Hack: -EINVAL is used to signal that a packet
372 * should be silently discarded. This is typically
373 * because we asked key management for an SA and
374 * it was delayed (e.g. kicked up to IKE).
376 if (*error == -EINVAL)
380 /* No IPsec processing for this packet. */
384 * If deferred crypto processing is needed, check that
385 * the interface supports it.
387 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
388 if (mtag != NULL && ifp != NULL &&
389 ((*ifp)->if_capenable & IFCAP_IPSEC) == 0) {
390 /* notify IPsec to do its own crypto */
391 ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
392 *error = EHOSTUNREACH;