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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>
48 #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>
60 #include <netinet/sctp_crc32.h>
63 #include <machine/in_cksum.h>
66 #include <netipsec/ipsec.h>
67 #include <netipsec/xform.h>
68 #include <netipsec/key.h>
71 extern struct protosw inetsw[];
74 #ifdef IPSEC_FILTERTUNNEL
75 static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 1;
77 static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 0;
79 #define V_ip4_ipsec_filtertunnel VNET(ip4_ipsec_filtertunnel)
81 SYSCTL_DECL(_net_inet_ipsec);
82 SYSCTL_VNET_INT(_net_inet_ipsec, OID_AUTO, filtertunnel,
83 CTLFLAG_RW, &VNET_NAME(ip4_ipsec_filtertunnel), 0,
84 "If set filter packets from an IPsec tunnel.");
88 * Check if we have to jump over firewall processing for this packet.
89 * Called from ip_input().
90 * 1 = jump over firewall, 0 = packet goes through firewall.
93 ip_ipsec_filtertunnel(struct mbuf *m)
98 * Bypass packet filtering for packets previously handled by IPsec.
100 if (!V_ip4_ipsec_filtertunnel &&
101 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
108 * Check if this packet has an active SA and needs to be dropped instead
110 * Called from ip_input().
111 * 1 = drop packet, 0 = forward packet.
114 ip_ipsec_fwd(struct mbuf *m)
118 struct tdb_ident *tdbi;
119 struct secpolicy *sp;
122 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
125 tdbi = (struct tdb_ident *)(mtag + 1);
126 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
128 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
129 IP_FORWARDING, &error);
131 if (sp == NULL) { /* NB: can happen if error */
133 /*XXX error stat???*/
134 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
139 * Check security policy against packet attributes.
141 error = ipsec_in_reject(sp, m);
145 IPSTAT_INC(ips_cantforward);
153 * Check if protocol type doesn't have a further header and do IPSEC
154 * decryption or reject right now. Protocols with further headers get
155 * their IPSEC treatment within the protocol specific processing.
156 * Called from ip_input().
157 * 1 = drop packet, 0 = continue processing packet.
160 ip_ipsec_input(struct mbuf *m)
163 struct ip *ip = mtod(m, struct ip *);
165 struct tdb_ident *tdbi;
166 struct secpolicy *sp;
169 * enforce IPsec policy checking if we are seeing last header.
170 * note that we do not visit this with protocols with pcb layer
171 * code - like udp/tcp/raw ip.
173 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
175 * Check if the packet has already had IPsec processing
176 * done. If so, then just pass it along. This tag gets
177 * set during AH, ESP, etc. input handling, before the
178 * packet is returned to the ip input queue for delivery.
180 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
183 tdbi = (struct tdb_ident *)(mtag + 1);
184 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
186 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
187 IP_FORWARDING, &error);
191 * Check security policy against packet attributes.
193 error = ipsec_in_reject(sp, m);
196 /* XXX error stat??? */
198 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
210 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
211 * Called from ip_forward().
212 * Returns MTU suggestion for ICMP needfrag reply.
215 ip_ipsec_mtu(struct mbuf *m, int mtu)
218 * If the packet is routed over IPsec tunnel, tell the
219 * originator the tunnel MTU.
220 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
223 struct secpolicy *sp = NULL;
227 sp = ipsec_getpolicybyaddr(m,
232 /* count IPsec header size */
233 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
236 * find the correct route for outer IPv4
237 * header, compute tunnel MTU.
239 if (sp->req != NULL &&
240 sp->req->sav != NULL &&
241 sp->req->sav->sah != NULL) {
242 ro = &sp->req->sav->sah->route_cache.sa_route;
243 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
245 ro->ro_rt->rt_rmx.rmx_mtu ?
246 ro->ro_rt->rt_rmx.rmx_mtu :
247 ro->ro_rt->rt_ifp->if_mtu;
258 * Called from ip_output().
259 * 1 = drop packet, 0 = continue processing packet,
260 * -1 = packet was reinjected and stop processing packet
263 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
267 struct secpolicy *sp = NULL;
268 struct ip *ip = mtod(*m, struct ip *);
269 struct tdb_ident *tdbi;
273 * Check the security policy (SP) for the packet and, if
274 * required, do IPsec-related processing. There are two
275 * cases here; the first time a packet is sent through
276 * it will be untagged and handled by ipsec4_checkpolicy.
277 * If the packet is resubmitted to ip_output (e.g. after
278 * AH, ESP, etc. processing), there will be a tag to bypass
279 * the lookup and related policy checking.
281 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
284 tdbi = (struct tdb_ident *)(mtag + 1);
285 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
287 *error = -EINVAL; /* force silent drop */
288 m_tag_delete(*m, mtag);
290 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
294 * There are four return cases:
295 * sp != NULL apply IPsec policy
296 * sp == NULL, error == 0 no IPsec handling needed
297 * sp == NULL, error == -EINVAL discard packet w/o error
298 * sp == NULL, error != 0 discard packet, report error
301 /* Loop detection, check if ipsec processing already done */
302 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
303 for (mtag = m_tag_first(*m); mtag != NULL;
304 mtag = m_tag_next(*m, mtag)) {
305 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
307 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
308 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
311 * Check if policy has an SA associated with it.
312 * This can happen when an SP has yet to acquire
313 * an SA; e.g. on first reference. If it occurs,
314 * then we let ipsec4_process_packet do its thing.
316 if (sp->req->sav == NULL)
318 tdbi = (struct tdb_ident *)(mtag + 1);
319 if (tdbi->spi == sp->req->sav->spi &&
320 tdbi->proto == sp->req->sav->sah->saidx.proto &&
321 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
322 sizeof (union sockaddr_union)) == 0) {
324 * No IPsec processing is needed, free
327 * NB: null pointer to avoid free at
330 KEY_FREESP(&sp), sp = NULL;
337 * Do delayed checksums now because we send before
338 * this is done in the normal processing path.
340 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
341 in_delayed_cksum(*m);
342 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
345 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
346 sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2));
347 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
350 ip->ip_len = htons(ip->ip_len);
351 ip->ip_off = htons(ip->ip_off);
353 /* NB: callee frees mbuf */
354 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
355 if (*error == EJUSTRETURN) {
357 * We had a SP with a level of 'use' and no SA. We
358 * will just continue to process the packet without
359 * IPsec processing and return without error.
362 ip->ip_len = ntohs(ip->ip_len);
363 ip->ip_off = ntohs(ip->ip_off);
367 * Preserve KAME behaviour: ENOENT can be returned
368 * when an SA acquire is in progress. Don't propagate
369 * this to user-level; it confuses applications.
371 * XXX this will go away when the SADB is redone.
373 if (*error == ENOENT)
377 } else { /* sp == NULL */
382 * Hack: -EINVAL is used to signal that a packet
383 * should be silently discarded. This is typically
384 * because we asked key management for an SA and
385 * it was delayed (e.g. kicked up to IKE).
387 if (*error == -EINVAL)
391 /* No IPsec processing for this packet. */
395 * If deferred crypto processing is needed, check that
396 * the interface supports it.
398 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
399 if (mtag != NULL && ifp != NULL &&
400 ((*ifp)->if_capenable & IFCAP_IPSEC) == 0) {
401 /* notify IPsec to do its own crypto */
402 ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
403 *error = EHOSTUNREACH;