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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/if_var.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>
65 #include <netipsec/ipsec.h>
66 #include <netipsec/xform.h>
67 #include <netipsec/key.h>
69 extern struct protosw inetsw[];
71 static VNET_DEFINE(int, ip4_ipsec_filtertunnel) = 0;
72 #define V_ip4_ipsec_filtertunnel VNET(ip4_ipsec_filtertunnel)
74 SYSCTL_DECL(_net_inet_ipsec);
75 SYSCTL_INT(_net_inet_ipsec, OID_AUTO, filtertunnel,
76 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip4_ipsec_filtertunnel), 0,
77 "If set filter packets from an IPsec tunnel.");
80 * Check if we have to jump over firewall processing for this packet.
81 * Called from ip_input().
82 * 1 = jump over firewall, 0 = packet goes through firewall.
85 ip_ipsec_filtertunnel(struct mbuf *m)
89 * Bypass packet filtering for packets previously handled by IPsec.
91 if (!V_ip4_ipsec_filtertunnel &&
92 m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
98 * Check if this packet has an active SA and needs to be dropped instead
100 * Called from ip_forward().
101 * 1 = drop packet, 0 = forward packet.
104 ip_ipsec_fwd(struct mbuf *m)
107 return (ipsec4_in_reject(m, NULL));
111 * Check if protocol type doesn't have a further header and do IPSEC
112 * decryption or reject right now. Protocols with further headers get
113 * their IPSEC treatment within the protocol specific processing.
114 * Called from ip_input().
115 * 1 = drop packet, 0 = continue processing packet.
118 ip_ipsec_input(struct mbuf *m, int nxt)
121 * enforce IPsec policy checking if we are seeing last header.
122 * note that we do not visit this with protocols with pcb layer
123 * code - like udp/tcp/raw ip.
125 if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) != 0)
126 return (ipsec4_in_reject(m, NULL));
131 * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
132 * Called from ip_forward().
133 * Returns MTU suggestion for ICMP needfrag reply.
136 ip_ipsec_mtu(struct mbuf *m, int mtu)
139 * If the packet is routed over IPsec tunnel, tell the
140 * originator the tunnel MTU.
141 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
144 return (mtu - ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL));
149 * Called from ip_output().
150 * 1 = drop packet, 0 = continue processing packet,
151 * -1 = packet was reinjected and stop processing packet
154 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *error)
156 struct secpolicy *sp;
158 if (!key_havesp(IPSEC_DIR_OUTBOUND))
162 * Check the security policy (SP) for the packet and, if
163 * required, do IPsec-related processing. There are two
164 * cases here; the first time a packet is sent through
165 * it will be untagged and handled by ipsec4_checkpolicy.
166 * If the packet is resubmitted to ip_output (e.g. after
167 * AH, ESP, etc. processing), there will be a tag to bypass
168 * the lookup and related policy checking.
170 if (m_tag_find(*m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) {
174 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, error, inp);
176 * There are four return cases:
177 * sp != NULL apply IPsec policy
178 * sp == NULL, error == 0 no IPsec handling needed
179 * sp == NULL, error == -EINVAL discard packet w/o error
180 * sp == NULL, error != 0 discard packet, report error
184 * Do delayed checksums now because we send before
185 * this is done in the normal processing path.
187 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
188 in_delayed_cksum(*m);
189 (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
192 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP) {
193 struct ip *ip = mtod(*m, struct ip *);
195 sctp_delayed_cksum(*m, (uint32_t)(ip->ip_hl << 2));
196 (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP;
200 /* NB: callee frees mbuf */
201 *error = ipsec4_process_packet(*m, sp->req);
203 if (*error == EJUSTRETURN) {
205 * We had a SP with a level of 'use' and no SA. We
206 * will just continue to process the packet without
207 * IPsec processing and return without error.
213 * Preserve KAME behaviour: ENOENT can be returned
214 * when an SA acquire is in progress. Don't propagate
215 * this to user-level; it confuses applications.
217 * XXX this will go away when the SADB is redone.
219 if (*error == ENOENT)
222 } else { /* sp == NULL */
226 * Hack: -EINVAL is used to signal that a packet
227 * should be silently discarded. This is typically
228 * because we asked key management for an SA and
229 * it was delayed (e.g. kicked up to IKE).
231 if (*error == -EINVAL)
235 /* No IPsec processing for this packet. */