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30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include "opt_ipsec.h"
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/errno.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
43 #include <sys/socketvar.h>
44 #include <sys/sysctl.h>
45 #include <sys/vimage.h>
48 #include <net/route.h>
50 #include <netinet/in.h>
51 #include <netinet/in_systm.h>
52 #include <netinet/in_var.h>
53 #include <netinet/ip.h>
54 #include <netinet/in_pcb.h>
55 #include <netinet/ip_var.h>
56 #include <netinet/ip_options.h>
57 #include <netinet/ip_ipsec.h>
58 #include <netinet/vinet.h>
60 #include <machine/in_cksum.h>
63 #include <netipsec/ipsec.h>
64 #include <netipsec/xform.h>
65 #include <netipsec/key.h>
68 extern struct protosw inetsw[];
71 * Check if we have to jump over firewall processing for this packet.
72 * Called from ip_input().
73 * 1 = jump over firewall, 0 = packet goes through firewall.
76 ip_ipsec_filtertunnel(struct mbuf *m)
78 #if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
80 * Bypass packet filtering for packets from a tunnel.
82 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
89 * Check if this packet has an active SA and needs to be dropped instead
91 * Called from ip_input().
92 * 1 = drop packet, 0 = forward packet.
95 ip_ipsec_fwd(struct mbuf *m)
98 INIT_VNET_INET(curvnet);
99 INIT_VNET_IPSEC(curvnet);
101 struct tdb_ident *tdbi;
102 struct secpolicy *sp;
105 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
108 tdbi = (struct tdb_ident *)(mtag + 1);
109 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
111 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
112 IP_FORWARDING, &error);
114 if (sp == NULL) { /* NB: can happen if error */
116 /*XXX error stat???*/
117 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
122 * Check security policy against packet attributes.
124 error = ipsec_in_reject(sp, m);
128 V_ipstat.ips_cantforward++;
136 * Check if protocol type doesn't have a further header and do IPSEC
137 * decryption or reject right now. Protocols with further headers get
138 * their IPSEC treatment within the protocol specific processing.
139 * Called from ip_input().
140 * 1 = drop packet, 0 = continue processing packet.
143 ip_ipsec_input(struct mbuf *m)
145 struct ip *ip = mtod(m, struct ip *);
147 INIT_VNET_IPSEC(curvnet);
149 struct tdb_ident *tdbi;
150 struct secpolicy *sp;
153 * enforce IPsec policy checking if we are seeing last header.
154 * note that we do not visit this with protocols with pcb layer
155 * code - like udp/tcp/raw ip.
157 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
159 * Check if the packet has already had IPsec processing
160 * done. If so, then just pass it along. This tag gets
161 * set during AH, ESP, etc. input handling, before the
162 * packet is returned to the ip input queue for delivery.
164 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
167 tdbi = (struct tdb_ident *)(mtag + 1);
168 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
170 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
171 IP_FORWARDING, &error);
175 * Check security policy against packet attributes.
177 error = ipsec_in_reject(sp, m);
180 /* XXX error stat??? */
182 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
194 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
195 * Called from ip_forward().
196 * Returns MTU suggestion for ICMP needfrag reply.
199 ip_ipsec_mtu(struct mbuf *m, int mtu)
202 * If the packet is routed over IPsec tunnel, tell the
203 * originator the tunnel MTU.
204 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
207 struct secpolicy *sp = NULL;
211 sp = ipsec_getpolicybyaddr(m,
216 /* count IPsec header size */
217 ipsechdr = ipsec4_hdrsiz(m,
222 * find the correct route for outer IPv4
223 * header, compute tunnel MTU.
225 if (sp->req != NULL &&
226 sp->req->sav != NULL &&
227 sp->req->sav->sah != NULL) {
228 ro = &sp->req->sav->sah->sa_route;
229 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
231 ro->ro_rt->rt_rmx.rmx_mtu ?
232 ro->ro_rt->rt_rmx.rmx_mtu :
233 ro->ro_rt->rt_ifp->if_mtu;
244 * Called from ip_output().
245 * 1 = drop packet, 0 = continue processing packet,
246 * -1 = packet was reinjected and stop processing packet
249 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
250 struct route **ro, struct route *iproute, struct sockaddr_in **dst,
251 struct in_ifaddr **ia, struct ifnet **ifp)
254 struct secpolicy *sp = NULL;
255 struct ip *ip = mtod(*m, struct ip *);
256 struct tdb_ident *tdbi;
260 * Check the security policy (SP) for the packet and, if
261 * required, do IPsec-related processing. There are two
262 * cases here; the first time a packet is sent through
263 * it will be untagged and handled by ipsec4_checkpolicy.
264 * If the packet is resubmitted to ip_output (e.g. after
265 * AH, ESP, etc. processing), there will be a tag to bypass
266 * the lookup and related policy checking.
268 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
271 tdbi = (struct tdb_ident *)(mtag + 1);
272 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
274 *error = -EINVAL; /* force silent drop */
275 m_tag_delete(*m, mtag);
277 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
281 * There are four return cases:
282 * sp != NULL apply IPsec policy
283 * sp == NULL, error == 0 no IPsec handling needed
284 * sp == NULL, error == -EINVAL discard packet w/o error
285 * sp == NULL, error != 0 discard packet, report error
288 /* Loop detection, check if ipsec processing already done */
289 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
290 for (mtag = m_tag_first(*m); mtag != NULL;
291 mtag = m_tag_next(*m, mtag)) {
292 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
294 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
295 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
298 * Check if policy has an SA associated with it.
299 * This can happen when an SP has yet to acquire
300 * an SA; e.g. on first reference. If it occurs,
301 * then we let ipsec4_process_packet do its thing.
303 if (sp->req->sav == NULL)
305 tdbi = (struct tdb_ident *)(mtag + 1);
306 if (tdbi->spi == sp->req->sav->spi &&
307 tdbi->proto == sp->req->sav->sah->saidx.proto &&
308 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
309 sizeof (union sockaddr_union)) == 0) {
311 * No IPsec processing is needed, free
314 * NB: null pointer to avoid free at
317 KEY_FREESP(&sp), sp = NULL;
324 * Do delayed checksums now because we send before
325 * this is done in the normal processing path.
327 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
328 in_delayed_cksum(*m);
329 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
332 ip->ip_len = htons(ip->ip_len);
333 ip->ip_off = htons(ip->ip_off);
335 /* NB: callee frees mbuf */
336 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
337 if (*error == EJUSTRETURN) {
339 * We had a SP with a level of 'use' and no SA. We
340 * will just continue to process the packet without
341 * IPsec processing and return without error.
344 ip->ip_len = ntohs(ip->ip_len);
345 ip->ip_off = ntohs(ip->ip_off);
349 * Preserve KAME behaviour: ENOENT can be returned
350 * when an SA acquire is in progress. Don't propagate
351 * this to user-level; it confuses applications.
353 * XXX this will go away when the SADB is redone.
355 if (*error == ENOENT)
359 } else { /* sp == NULL */
364 * Hack: -EINVAL is used to signal that a packet
365 * should be silently discarded. This is typically
366 * because we asked key management for an SA and
367 * it was delayed (e.g. kicked up to IKE).
369 if (*error == -EINVAL)
373 /* No IPsec processing for this packet. */
377 * If deferred crypto processing is needed, check that
378 * the interface supports it.
380 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
381 if (mtag != NULL && ((*ifp)->if_capenable & IFCAP_IPSEC) == 0) {
382 /* notify IPsec to do its own crypto */
383 ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
384 *error = EHOSTUNREACH;