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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);
124 tdbi = (struct tdb_ident *)(mtag + 1);
125 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
127 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
128 IP_FORWARDING, &error);
130 if (sp == NULL) { /* NB: can happen if error */
131 /*XXX error stat???*/
132 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
137 * Check security policy against packet attributes.
139 error = ipsec_in_reject(sp, m);
142 IPSTAT_INC(ips_cantforward);
150 * Check if protocol type doesn't have a further header and do IPSEC
151 * decryption or reject right now. Protocols with further headers get
152 * their IPSEC treatment within the protocol specific processing.
153 * Called from ip_input().
154 * 1 = drop packet, 0 = continue processing packet.
157 ip_ipsec_input(struct mbuf *m)
160 struct ip *ip = mtod(m, struct ip *);
162 struct tdb_ident *tdbi;
163 struct secpolicy *sp;
166 * enforce IPsec policy checking if we are seeing last header.
167 * note that we do not visit this with protocols with pcb layer
168 * code - like udp/tcp/raw ip.
170 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
172 * Check if the packet has already had IPsec processing
173 * done. If so, then just pass it along. This tag gets
174 * set during AH, ESP, etc. input handling, before the
175 * packet is returned to the ip input queue for delivery.
177 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
179 tdbi = (struct tdb_ident *)(mtag + 1);
180 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
182 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
183 IP_FORWARDING, &error);
187 * Check security policy against packet attributes.
189 error = ipsec_in_reject(sp, m);
192 /* XXX error stat??? */
194 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->route_cache.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)
261 struct secpolicy *sp = NULL;
262 struct tdb_ident *tdbi;
265 * Check the security policy (SP) for the packet and, if
266 * required, do IPsec-related processing. There are two
267 * cases here; the first time a packet is sent through
268 * it will be untagged and handled by ipsec4_checkpolicy.
269 * If the packet is resubmitted to ip_output (e.g. after
270 * AH, ESP, etc. processing), there will be a tag to bypass
271 * the lookup and related policy checking.
273 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
275 tdbi = (struct tdb_ident *)(mtag + 1);
276 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
278 *error = -EINVAL; /* force silent drop */
279 m_tag_delete(*m, mtag);
281 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
285 * There are four return cases:
286 * sp != NULL apply IPsec policy
287 * sp == NULL, error == 0 no IPsec handling needed
288 * sp == NULL, error == -EINVAL discard packet w/o error
289 * sp == NULL, error != 0 discard packet, report error
292 /* Loop detection, check if ipsec processing already done */
293 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
294 for (mtag = m_tag_first(*m); mtag != NULL;
295 mtag = m_tag_next(*m, mtag)) {
296 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
298 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
299 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
302 * Check if policy has an SA associated with it.
303 * This can happen when an SP has yet to acquire
304 * an SA; e.g. on first reference. If it occurs,
305 * then we let ipsec4_process_packet do its thing.
307 if (sp->req->sav == NULL)
309 tdbi = (struct tdb_ident *)(mtag + 1);
310 if (tdbi->spi == sp->req->sav->spi &&
311 tdbi->proto == sp->req->sav->sah->saidx.proto &&
312 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
313 sizeof (union sockaddr_union)) == 0) {
315 * No IPsec processing is needed, free
318 * NB: null pointer to avoid free at
321 KEY_FREESP(&sp), sp = NULL;
327 * Do delayed checksums now because we send before
328 * this is done in the normal processing path.
330 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
331 in_delayed_cksum(*m);
332 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
335 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
336 struct ip *ip = mtod(*m, struct ip *);
338 sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2));
339 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
343 /* NB: callee frees mbuf */
344 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
345 if (*error == EJUSTRETURN) {
347 * We had a SP with a level of 'use' and no SA. We
348 * will just continue to process the packet without
349 * IPsec processing and return without error.
355 * Preserve KAME behaviour: ENOENT can be returned
356 * when an SA acquire is in progress. Don't propagate
357 * this to user-level; it confuses applications.
359 * XXX this will go away when the SADB is redone.
361 if (*error == ENOENT)
364 } else { /* sp == NULL */
368 * Hack: -EINVAL is used to signal that a packet
369 * should be silently discarded. This is typically
370 * because we asked key management for an SA and
371 * it was delayed (e.g. kicked up to IKE).
373 if (*error == -EINVAL)
377 /* No IPsec processing for this packet. */