2 * Copyright (C) 2001-2003 by Darren Reed
4 * See the IPFILTER.LICENCE file for details on licencing.
6 * Simple ISAKMP transparent proxy for in-kernel use. For use with the NAT
9 * $Id: ip_ipsec_pxy.c,v 2.20.2.8 2006/07/14 06:12:14 darrenr Exp $
12 #define IPF_IPSEC_PROXY
15 int ippr_ipsec_init __P((void));
16 void ippr_ipsec_fini __P((void));
17 int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *));
18 void ippr_ipsec_del __P((ap_session_t *));
19 int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *));
20 int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
22 static frentry_t ipsecfr;
23 static ipftq_t *ipsecnattqe;
24 static ipftq_t *ipsecstatetqe;
25 static char ipsec_buffer[1500];
27 int ipsec_proxy_init = 0;
28 int ipsec_proxy_ttl = 60;
31 * IPSec application proxy initialization.
35 bzero((char *)&ipsecfr, sizeof(ipsecfr));
37 ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
38 MUTEX_INIT(&ipsecfr.fr_lock, "IPsec proxy rule lock");
41 ipsecnattqe = fr_addtimeoutqueue(&nat_utqe, ipsec_proxy_ttl);
42 if (ipsecnattqe == NULL)
44 ipsecstatetqe = fr_addtimeoutqueue(&ips_utqe, ipsec_proxy_ttl);
45 if (ipsecstatetqe == NULL) {
46 if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
47 fr_freetimeoutqueue(ipsecnattqe);
52 ipsecnattqe->ifq_flags |= IFQF_PROXY;
53 ipsecstatetqe->ifq_flags |= IFQF_PROXY;
55 ipsecfr.fr_age[0] = ipsec_proxy_ttl;
56 ipsecfr.fr_age[1] = ipsec_proxy_ttl;
61 void ippr_ipsec_fini()
63 if (ipsecnattqe != NULL) {
64 if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
65 fr_freetimeoutqueue(ipsecnattqe);
68 if (ipsecstatetqe != NULL) {
69 if (fr_deletetimeoutqueue(ipsecstatetqe) == 0)
70 fr_freetimeoutqueue(ipsecstatetqe);
74 if (ipsec_proxy_init == 1) {
75 MUTEX_DESTROY(&ipsecfr.fr_lock);
82 * Setup for a new IPSEC proxy.
84 int ippr_ipsec_new(fin, aps, nat)
93 int p, off, dlen, ttl;
97 off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
98 bzero(ipsec_buffer, sizeof(ipsec_buffer));
102 dlen = M_LEN(m) - off;
105 COPYDATA(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
107 if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
111 aps->aps_psiz = sizeof(*ipsec);
112 KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
113 if (aps->aps_data == NULL)
116 ipsec = aps->aps_data;
117 bzero((char *)ipsec, sizeof(*ipsec));
120 * Create NAT rule against which the tunnel/transport mapping is
121 * created. This is required because the current NAT rule does not
122 * describe ESP but UDP instead.
124 ipn = &ipsec->ipsc_rule;
125 ttl = IPF_TTLVAL(ipsecnattqe->ifq_ttl);
126 ipn->in_tqehead[0] = fr_addtimeoutqueue(&nat_utqe, ttl);
127 ipn->in_tqehead[1] = fr_addtimeoutqueue(&nat_utqe, ttl);
128 ipn->in_ifps[0] = fin->fin_ifp;
132 ipn->in_nip = ntohl(nat->nat_outip.s_addr);
134 ipn->in_inip = nat->nat_inip.s_addr;
135 ipn->in_inmsk = 0xffffffff;
136 ipn->in_outip = fin->fin_saddr;
137 ipn->in_outmsk = nat->nat_outip.s_addr;
138 ipn->in_srcip = fin->fin_saddr;
139 ipn->in_srcmsk = 0xffffffff;
140 ipn->in_redir = NAT_MAP;
141 bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
142 sizeof(ipn->in_ifnames[0]));
143 ipn->in_p = IPPROTO_ESP;
145 bcopy((char *)fin, (char *)&fi, sizeof(fi));
148 fi.fin_fi.fi_p = IPPROTO_ESP;
149 fi.fin_fr = &ipsecfr;
153 ip->ip_p = IPPROTO_ESP;
154 fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
155 fi.fin_flx |= FI_IGNORE;
158 bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
159 ptr += sizeof(ipsec_cookie_t);
160 bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
162 * The responder cookie should only be non-zero if the initiator
163 * cookie is non-zero. Therefore, it is safe to assume(!) that the
164 * cookies are both set after copying if the responder is non-zero.
166 if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
167 ipsec->ipsc_rckset = 1;
169 ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
170 NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
171 if (ipsec->ipsc_nat != NULL) {
172 (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
173 nat_update(&fi, ipsec->ipsc_nat, ipn);
177 ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
179 if (fi.fin_state != NULL)
180 fr_statederef((ipstate_t **)&fi.fin_state);
188 * For outgoing IKE packets. refresh timeouts for NAT & state entries, if
189 * we can. If they have disappeared, recreate them.
191 int ippr_ipsec_inout(fin, aps, nat)
201 if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
204 if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
207 ipsec = aps->aps_data;
213 if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
214 bcopy((char *)fin, (char *)&fi, sizeof(fi));
217 fi.fin_fi.fi_p = IPPROTO_ESP;
218 fi.fin_fr = &ipsecfr;
221 ip->ip_p = IPPROTO_ESP;
222 fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
223 fi.fin_flx |= FI_IGNORE;
227 * Update NAT timeout/create NAT if missing.
229 if (ipsec->ipsc_nat != NULL)
230 fr_queueback(&ipsec->ipsc_nat->nat_tqe);
232 ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
236 if (ipsec->ipsc_nat != NULL) {
237 (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
238 nat_update(&fi, ipsec->ipsc_nat,
244 * Update state timeout/create state if missing.
246 READ_ENTER(&ipf_state);
247 if (ipsec->ipsc_state != NULL) {
248 fr_queueback(&ipsec->ipsc_state->is_sti);
249 ipsec->ipsc_state->is_die = nat->nat_age;
250 RWLOCK_EXIT(&ipf_state);
252 RWLOCK_EXIT(&ipf_state);
255 ipsec->ipsc_state = fr_addstate(&fi,
258 if (fi.fin_state != NULL)
259 fr_statederef((ipstate_t **)&fi.fin_state);
268 * This extends the NAT matching to be based on the cookies associated with
269 * a session and found at the front of IKE packets. The cookies are always
270 * in the same order (not reversed depending on packet flow direction as with
271 * UDP/TCP port numbers).
273 int ippr_ipsec_match(fin, aps, nat)
283 nat = nat; /* LINT */
285 if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
288 off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
289 ipsec = aps->aps_data;
291 COPYDATA(m, off, sizeof(cookies), (char *)cookies);
293 if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
294 (cookies[1] != ipsec->ipsc_icookie[1]))
297 if (ipsec->ipsc_rckset == 0) {
298 if ((cookies[2]|cookies[3]) == 0) {
301 ipsec->ipsc_rckset = 1;
302 ipsec->ipsc_rcookie[0] = cookies[2];
303 ipsec->ipsc_rcookie[1] = cookies[3];
307 if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
308 (cookies[3] != ipsec->ipsc_rcookie[1]))
315 * clean up after ourselves.
317 void ippr_ipsec_del(aps)
322 ipsec = aps->aps_data;
326 * Don't bother changing any of the NAT structure details,
327 * *_del() is on a callback from aps_free(), from nat_delete()
330 READ_ENTER(&ipf_state);
331 if (ipsec->ipsc_state != NULL) {
332 ipsec->ipsc_state->is_die = fr_ticks + 1;
333 ipsec->ipsc_state->is_me = NULL;
334 fr_queuefront(&ipsec->ipsc_state->is_sti);
336 RWLOCK_EXIT(&ipf_state);
338 ipsec->ipsc_state = NULL;
339 ipsec->ipsc_nat = NULL;