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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 int ip4_ipsec_filtertunnel;
79 * Check if we have to jump over firewall processing for this packet.
80 * Called from ip_input().
81 * 1 = jump over firewall, 0 = packet goes through firewall.
84 ip_ipsec_filtertunnel(struct mbuf *m)
87 INIT_VNET_IPSEC(curvnet);
90 * Bypass packet filtering for packets from a tunnel.
92 if (!V_ip4_ipsec_filtertunnel &&
93 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
100 * Check if this packet has an active SA and needs to be dropped instead
102 * Called from ip_input().
103 * 1 = drop packet, 0 = forward packet.
106 ip_ipsec_fwd(struct mbuf *m)
109 INIT_VNET_INET(curvnet);
110 INIT_VNET_IPSEC(curvnet);
112 struct tdb_ident *tdbi;
113 struct secpolicy *sp;
116 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
119 tdbi = (struct tdb_ident *)(mtag + 1);
120 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
122 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
123 IP_FORWARDING, &error);
125 if (sp == NULL) { /* NB: can happen if error */
127 /*XXX error stat???*/
128 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
133 * Check security policy against packet attributes.
135 error = ipsec_in_reject(sp, m);
139 IPSTAT_INC(ips_cantforward);
147 * Check if protocol type doesn't have a further header and do IPSEC
148 * decryption or reject right now. Protocols with further headers get
149 * their IPSEC treatment within the protocol specific processing.
150 * Called from ip_input().
151 * 1 = drop packet, 0 = continue processing packet.
154 ip_ipsec_input(struct mbuf *m)
156 struct ip *ip = mtod(m, struct ip *);
158 INIT_VNET_IPSEC(curvnet);
160 struct tdb_ident *tdbi;
161 struct secpolicy *sp;
164 * enforce IPsec policy checking if we are seeing last header.
165 * note that we do not visit this with protocols with pcb layer
166 * code - like udp/tcp/raw ip.
168 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
170 * Check if the packet has already had IPsec processing
171 * done. If so, then just pass it along. This tag gets
172 * set during AH, ESP, etc. input handling, before the
173 * packet is returned to the ip input queue for delivery.
175 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
178 tdbi = (struct tdb_ident *)(mtag + 1);
179 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
181 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
182 IP_FORWARDING, &error);
186 * Check security policy against packet attributes.
188 error = ipsec_in_reject(sp, m);
191 /* XXX error stat??? */
193 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
205 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
206 * Called from ip_forward().
207 * Returns MTU suggestion for ICMP needfrag reply.
210 ip_ipsec_mtu(struct mbuf *m, int mtu)
213 * If the packet is routed over IPsec tunnel, tell the
214 * originator the tunnel MTU.
215 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
218 struct secpolicy *sp = NULL;
222 sp = ipsec_getpolicybyaddr(m,
227 /* count IPsec header size */
228 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
231 * find the correct route for outer IPv4
232 * header, compute tunnel MTU.
234 if (sp->req != NULL &&
235 sp->req->sav != NULL &&
236 sp->req->sav->sah != NULL) {
237 ro = &sp->req->sav->sah->sa_route;
238 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
240 ro->ro_rt->rt_rmx.rmx_mtu ?
241 ro->ro_rt->rt_rmx.rmx_mtu :
242 ro->ro_rt->rt_ifp->if_mtu;
253 * Called from ip_output().
254 * 1 = drop packet, 0 = continue processing packet,
255 * -1 = packet was reinjected and stop processing packet
258 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
259 struct route **ro, struct route *iproute, struct sockaddr_in **dst,
260 struct in_ifaddr **ia, struct ifnet **ifp)
263 struct secpolicy *sp = NULL;
264 struct ip *ip = mtod(*m, struct ip *);
265 struct tdb_ident *tdbi;
269 * Check the security policy (SP) for the packet and, if
270 * required, do IPsec-related processing. There are two
271 * cases here; the first time a packet is sent through
272 * it will be untagged and handled by ipsec4_checkpolicy.
273 * If the packet is resubmitted to ip_output (e.g. after
274 * AH, ESP, etc. processing), there will be a tag to bypass
275 * the lookup and related policy checking.
277 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
280 tdbi = (struct tdb_ident *)(mtag + 1);
281 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
283 *error = -EINVAL; /* force silent drop */
284 m_tag_delete(*m, mtag);
286 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
290 * There are four return cases:
291 * sp != NULL apply IPsec policy
292 * sp == NULL, error == 0 no IPsec handling needed
293 * sp == NULL, error == -EINVAL discard packet w/o error
294 * sp == NULL, error != 0 discard packet, report error
297 /* Loop detection, check if ipsec processing already done */
298 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
299 for (mtag = m_tag_first(*m); mtag != NULL;
300 mtag = m_tag_next(*m, mtag)) {
301 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
303 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
304 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
307 * Check if policy has an SA associated with it.
308 * This can happen when an SP has yet to acquire
309 * an SA; e.g. on first reference. If it occurs,
310 * then we let ipsec4_process_packet do its thing.
312 if (sp->req->sav == NULL)
314 tdbi = (struct tdb_ident *)(mtag + 1);
315 if (tdbi->spi == sp->req->sav->spi &&
316 tdbi->proto == sp->req->sav->sah->saidx.proto &&
317 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
318 sizeof (union sockaddr_union)) == 0) {
320 * No IPsec processing is needed, free
323 * NB: null pointer to avoid free at
326 KEY_FREESP(&sp), sp = NULL;
333 * Do delayed checksums now because we send before
334 * this is done in the normal processing path.
336 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
337 in_delayed_cksum(*m);
338 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
341 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
342 sctp_delayed_cksum(*m);
343 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
346 ip->ip_len = htons(ip->ip_len);
347 ip->ip_off = htons(ip->ip_off);
349 /* NB: callee frees mbuf */
350 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
351 if (*error == EJUSTRETURN) {
353 * We had a SP with a level of 'use' and no SA. We
354 * will just continue to process the packet without
355 * IPsec processing and return without error.
358 ip->ip_len = ntohs(ip->ip_len);
359 ip->ip_off = ntohs(ip->ip_off);
363 * Preserve KAME behaviour: ENOENT can be returned
364 * when an SA acquire is in progress. Don't propagate
365 * this to user-level; it confuses applications.
367 * XXX this will go away when the SADB is redone.
369 if (*error == ENOENT)
373 } else { /* sp == NULL */
378 * Hack: -EINVAL is used to signal that a packet
379 * should be silently discarded. This is typically
380 * because we asked key management for an SA and
381 * it was delayed (e.g. kicked up to IKE).
383 if (*error == -EINVAL)
387 /* No IPsec processing for this packet. */
391 * If deferred crypto processing is needed, check that
392 * the interface supports it.
394 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
395 if (mtag != NULL && ifp != NULL &&
396 ((*ifp)->if_capenable & IFCAP_IPSEC) == 0) {
397 /* notify IPsec to do its own crypto */
398 ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
399 *error = EHOSTUNREACH;