1 /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * Copyright (c) 2018 Andrey V. Elsukov <ae@FreeBSD.org>
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the project nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34 /*
35 * My grandfather said that there's a devil inside tunnelling technology...
36 *
37 * We have surprisingly many protocols that want packets with IP protocol
38 * #4 or #41. Here's a list of protocols that want protocol #41:
39 * RFC1933 configured tunnel
40 * RFC1933 automatic tunnel
41 * RFC2401 IPsec tunnel
42 * RFC2473 IPv6 generic packet tunnelling
43 * RFC2529 6over4 tunnel
44 * mobile-ip6 (uses RFC2473)
45 * RFC3056 6to4 tunnel
46 * isatap tunnel
47 * Here's a list of protocol that want protocol #4:
48 * RFC1853 IPv4-in-IPv4 tunnelling
49 * RFC2003 IPv4 encapsulation within IPv4
50 * RFC2344 reverse tunnelling for mobile-ip4
51 * RFC2401 IPsec tunnel
52 * Well, what can I say. They impose different en/decapsulation mechanism
53 * from each other, so they need separate protocol handler. The only one
54 * we can easily determine by protocol # is IPsec, which always has
55 * AH/ESP/IPComp header right after outer IP header.
56 *
57 * So, clearly good old protosw does not work for protocol #4 and #41.
58 * The code will let you match protocol via src/dst address pair.
59 */
60
61 #include <sys/cdefs.h>
62 __FBSDID("$FreeBSD: releng/12.0/sys/netinet/ip_encap.c 335924 2018-07-04 02:47:16Z mmacy $");
63
64 #include "opt_inet.h"
65 #include "opt_inet6.h"
66
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/kernel.h>
70 #include <sys/lock.h>
71 #include <sys/malloc.h>
72 #include <sys/mutex.h>
73 #include <sys/mbuf.h>
74 #include <sys/errno.h>
75 #include <sys/socket.h>
76
77 #include <net/if.h>
78 #include <net/if_var.h>
79
80 #include <netinet/in.h>
81 #include <netinet/ip_var.h>
82 #include <netinet/ip_encap.h>
83
84 #ifdef INET6
85 #include <netinet6/ip6_var.h>
86 #endif
87
88 static MALLOC_DEFINE(M_NETADDR, "encap_export_host",
89 "Export host address structure");
90
91 struct encaptab {
92 CK_LIST_ENTRY(encaptab) chain;
93 int proto;
94 int min_length;
95 int exact_match;
96 void *arg;
97
98 encap_lookup_t lookup;
99 encap_check_t check;
100 encap_input_t input;
101 };
102
103 CK_LIST_HEAD(encaptab_head, encaptab);
104 #ifdef INET
105 static struct encaptab_head ipv4_encaptab = CK_LIST_HEAD_INITIALIZER();
106 #endif
107 #ifdef INET6
108 static struct encaptab_head ipv6_encaptab = CK_LIST_HEAD_INITIALIZER();
109 #endif
110
111 static struct mtx encapmtx;
112 MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
113 #define ENCAP_WLOCK() mtx_lock(&encapmtx)
114 #define ENCAP_WUNLOCK() mtx_unlock(&encapmtx)
115 #define ENCAP_RLOCK() struct epoch_tracker encap_et; epoch_enter_preempt(net_epoch_preempt, &encap_et)
116 #define ENCAP_RUNLOCK() epoch_exit_preempt(net_epoch_preempt, &encap_et)
117 #define ENCAP_WAIT() epoch_wait_preempt(net_epoch_preempt)
118
119 static struct encaptab *
120 encap_attach(struct encaptab_head *head, const struct encap_config *cfg,
121 void *arg, int mflags)
122 {
123 struct encaptab *ep, *tmp;
124
125 if (cfg == NULL || cfg->input == NULL ||
126 (cfg->check == NULL && cfg->lookup == NULL) ||
127 (cfg->lookup != NULL && cfg->exact_match != ENCAP_DRV_LOOKUP) ||
128 (cfg->exact_match == ENCAP_DRV_LOOKUP && cfg->lookup == NULL))
129 return (NULL);
130
131 ep = malloc(sizeof(*ep), M_NETADDR, mflags);
132 if (ep == NULL)
133 return (NULL);
134
135 ep->proto = cfg->proto;
136 ep->min_length = cfg->min_length;
137 ep->exact_match = cfg->exact_match;
138 ep->arg = arg;
139 ep->lookup = cfg->exact_match == ENCAP_DRV_LOOKUP ? cfg->lookup: NULL;
140 ep->check = cfg->exact_match != ENCAP_DRV_LOOKUP ? cfg->check: NULL;
141 ep->input = cfg->input;
142
143 ENCAP_WLOCK();
144 CK_LIST_FOREACH(tmp, head, chain) {
145 if (tmp->exact_match <= ep->exact_match)
146 break;
147 }
148 if (tmp == NULL)
149 CK_LIST_INSERT_HEAD(head, ep, chain);
150 else
151 CK_LIST_INSERT_BEFORE(tmp, ep, chain);
152 ENCAP_WUNLOCK();
153 return (ep);
154 }
155
156 static int
157 encap_detach(struct encaptab_head *head, const struct encaptab *cookie)
158 {
159 struct encaptab *ep;
160
161 ENCAP_WLOCK();
162 CK_LIST_FOREACH(ep, head, chain) {
163 if (ep == cookie) {
164 CK_LIST_REMOVE(ep, chain);
165 ENCAP_WUNLOCK();
166 ENCAP_WAIT();
167 free(ep, M_NETADDR);
168 return (0);
169 }
170 }
171 ENCAP_WUNLOCK();
172 return (EINVAL);
173 }
174
175 static int
176 encap_input(struct encaptab_head *head, struct mbuf *m, int off, int proto)
177 {
178 struct encaptab *ep, *match;
179 void *arg;
180 int matchprio, ret;
181
182 match = NULL;
183 matchprio = 0;
184
185 ENCAP_RLOCK();
186 CK_LIST_FOREACH(ep, head, chain) {
187 if (ep->proto >= 0 && ep->proto != proto)
188 continue;
189 if (ep->min_length > m->m_pkthdr.len)
190 continue;
191 if (ep->exact_match == ENCAP_DRV_LOOKUP)
192 ret = (*ep->lookup)(m, off, proto, &arg);
193 else
194 ret = (*ep->check)(m, off, proto, ep->arg);
195 if (ret <= 0)
196 continue;
197 if (ret > matchprio) {
198 match = ep;
199 if (ep->exact_match != ENCAP_DRV_LOOKUP)
200 arg = ep->arg;
201 /*
202 * No need to continue the search, we got the
203 * exact match.
204 */
205 if (ret >= ep->exact_match)
206 break;
207 matchprio = ret;
208 }
209 }
210
211 if (match != NULL) {
212 /* found a match, "match" has the best one */
213 ret = (*match->input)(m, off, proto, arg);
214 ENCAP_RUNLOCK();
215 MPASS(ret == IPPROTO_DONE);
216 return (IPPROTO_DONE);
217 }
218 ENCAP_RUNLOCK();
219 return (0);
220 }
221
222 #ifdef INET
223 const struct encaptab *
224 ip_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
225 {
226
227 return (encap_attach(&ipv4_encaptab, cfg, arg, mflags));
228 }
229
230 int
231 ip_encap_detach(const struct encaptab *cookie)
232 {
233
234 return (encap_detach(&ipv4_encaptab, cookie));
235 }
236
237 int
238 encap4_input(struct mbuf **mp, int *offp, int proto)
239 {
240
241 if (encap_input(&ipv4_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
242 return (rip_input(mp, offp, proto));
243 return (IPPROTO_DONE);
244 }
245 #endif /* INET */
246
247 #ifdef INET6
248 const struct encaptab *
249 ip6_encap_attach(const struct encap_config *cfg, void *arg, int mflags)
250 {
251
252 return (encap_attach(&ipv6_encaptab, cfg, arg, mflags));
253 }
254
255 int
256 ip6_encap_detach(const struct encaptab *cookie)
257 {
258
259 return (encap_detach(&ipv6_encaptab, cookie));
260 }
261
262 int
263 encap6_input(struct mbuf **mp, int *offp, int proto)
264 {
265
266 if (encap_input(&ipv6_encaptab, *mp, *offp, proto) != IPPROTO_DONE)
267 return (rip6_input(mp, offp, proto));
268 return (IPPROTO_DONE);
269 }
270 #endif /* INET6 */
Cache object: b2151de64fa9858f648108c0930c333e
|