2/* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32/*
33 * My grandfather said that there's a devil inside tunnelling technology...
34 *
35 * We have surprisingly many protocols that want packets with IP protocol
36 * #4 or #41. Here's a list of protocols that want protocol #41:
37 * RFC1933 configured tunnel
38 * RFC1933 automatic tunnel
39 * RFC2401 IPsec tunnel
40 * RFC2473 IPv6 generic packet tunnelling
41 * RFC2529 6over4 tunnel
42 * mobile-ip6 (uses RFC2473)
43 * RFC3056 6to4 tunnel
44 * isatap tunnel
45 * Here's a list of protocol that want protocol #4:
46 * RFC1853 IPv4-in-IPv4 tunnelling
47 * RFC2003 IPv4 encapsulation within IPv4
48 * RFC2344 reverse tunnelling for mobile-ip4
49 * RFC2401 IPsec tunnel
50 * Well, what can I say. They impose different en/decapsulation mechanism
51 * from each other, so they need separate protocol handler. The only one
52 * we can easily determine by protocol # is IPsec, which always has
53 * AH/ESP/IPComp header right after outer IP header.
54 *
55 * So, clearly good old protosw does not work for protocol #4 and #41.
56 * The code will let you match protocol via src/dst address pair.
57 */
58/* XXX is M_NETADDR correct? */
59
60#include "opt_mrouting.h"
61#include "opt_inet.h"
62#include "opt_inet6.h"
63
64#include <sys/param.h>
65#include <sys/systm.h>
66#include <sys/socket.h>
67#include <sys/sockio.h>
68#include <sys/mbuf.h>
69#include <sys/errno.h>
70#include <sys/protosw.h>
71#include <sys/queue.h>
72
73#include <net/if.h>
74#include <net/route.h>
75
76#include <netinet/in.h>
77#include <netinet/in_systm.h>
78#include <netinet/ip.h>
79#include <netinet/ip_var.h>
80#include <netinet/ip_encap.h>
81
82#ifdef INET6
83#include <netinet/ip6.h>
84#include <netinet6/ip6_var.h>
85#include <netinet6/ip6protosw.h>
86#endif
87
88#include <machine/stdarg.h>
89
90#include <net/net_osdep.h>
91
92#include <sys/kernel.h>
93#include <sys/malloc.h>
94static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
95
96static void encap_add(struct encaptab *);
97static int mask_match(const struct encaptab *, const struct sockaddr *,
98 const struct sockaddr *);
99static void encap_fillarg(struct mbuf *, const struct encaptab *);
100
101#ifndef LIST_HEAD_INITIALIZER
102/* rely upon BSS initialization */
103LIST_HEAD(, encaptab) encaptab;
104#else
105LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
106#endif
107
108void
109encap_init()
110{
111 static int initialized = 0;
112
113 if (initialized)
114 return;
115 initialized++;
116#if 0
117 /*
118 * we cannot use LIST_INIT() here, since drivers may want to call
119 * encap_attach(), on driver attach. encap_init() will be called
120 * on AF_INET{,6} initialization, which happens after driver
121 * initialization - using LIST_INIT() here can nuke encap_attach()
122 * from drivers.
123 */
124 LIST_INIT(&encaptab);
125#endif
126}
127
128#ifdef INET
129void
130encap4_input(m, off)
131 struct mbuf *m;
132 int off;
133{
134 struct ip *ip;
135 int proto;
136 struct sockaddr_in s, d;
137 const struct protosw *psw;
138 struct encaptab *ep, *match;
139 int prio, matchprio;
140
141 ip = mtod(m, struct ip *);
142 proto = ip->ip_p;
143
144 bzero(&s, sizeof(s));
145 s.sin_family = AF_INET;
146 s.sin_len = sizeof(struct sockaddr_in);
147 s.sin_addr = ip->ip_src;
148 bzero(&d, sizeof(d));
149 d.sin_family = AF_INET;
150 d.sin_len = sizeof(struct sockaddr_in);
151 d.sin_addr = ip->ip_dst;
152
153 match = NULL;
154 matchprio = 0;
155 LIST_FOREACH(ep, &encaptab, chain) {
156 if (ep->af != AF_INET)
157 continue;
158 if (ep->proto >= 0 && ep->proto != proto)
159 continue;
160 if (ep->func)
161 prio = (*ep->func)(m, off, proto, ep->arg);
162 else {
163 /*
164 * it's inbound traffic, we need to match in reverse
165 * order
166 */
167 prio = mask_match(ep, (struct sockaddr *)&d,
168 (struct sockaddr *)&s);
169 }
170
171 /*
172 * We prioritize the matches by using bit length of the
173 * matches. mask_match() and user-supplied matching function
174 * should return the bit length of the matches (for example,
175 * if both src/dst are matched for IPv4, 64 should be returned).
176 * 0 or negative return value means "it did not match".
177 *
178 * The question is, since we have two "mask" portion, we
179 * cannot really define total order between entries.
180 * For example, which of these should be preferred?
181 * mask_match() returns 48 (32 + 16) for both of them.
182 * src=3ffe::/16, dst=3ffe:501::/32
183 * src=3ffe:501::/32, dst=3ffe::/16
184 *
185 * We need to loop through all the possible candidates
186 * to get the best match - the search takes O(n) for
187 * n attachments (i.e. interfaces).
188 */
189 if (prio <= 0)
190 continue;
191 if (prio > matchprio) {
192 matchprio = prio;
193 match = ep;
194 }
195 }
196
197 if (match) {
198 /* found a match, "match" has the best one */
199 psw = match->psw;
200 if (psw && psw->pr_input) {
201 encap_fillarg(m, match);
202 (*psw->pr_input)(m, off);
203 } else
204 m_freem(m);
205 return;
206 }
207
208 /* last resort: inject to raw socket */
209 rip_input(m, off);
210}
211#endif
212
213#ifdef INET6
214int
215encap6_input(mp, offp, proto)
216 struct mbuf **mp;
217 int *offp;
218 int proto;
219{
220 struct mbuf *m = *mp;
221 struct ip6_hdr *ip6;
222 struct sockaddr_in6 s, d;
223 const struct ip6protosw *psw;
224 struct encaptab *ep, *match;
225 int prio, matchprio;
226
227 ip6 = mtod(m, struct ip6_hdr *);
228
229 bzero(&s, sizeof(s));
230 s.sin6_family = AF_INET6;
231 s.sin6_len = sizeof(struct sockaddr_in6);
232 s.sin6_addr = ip6->ip6_src;
233 bzero(&d, sizeof(d));
234 d.sin6_family = AF_INET6;
235 d.sin6_len = sizeof(struct sockaddr_in6);
236 d.sin6_addr = ip6->ip6_dst;
237
238 match = NULL;
239 matchprio = 0;
240 LIST_FOREACH(ep, &encaptab, chain) {
241 if (ep->af != AF_INET6)
242 continue;
243 if (ep->proto >= 0 && ep->proto != proto)
244 continue;
245 if (ep->func)
246 prio = (*ep->func)(m, *offp, proto, ep->arg);
247 else {
248 /*
249 * it's inbound traffic, we need to match in reverse
250 * order
251 */
252 prio = mask_match(ep, (struct sockaddr *)&d,
253 (struct sockaddr *)&s);
254 }
255
256 /* see encap4_input() for issues here */
257 if (prio <= 0)
258 continue;
259 if (prio > matchprio) {
260 matchprio = prio;
261 match = ep;
262 }
263 }
264
265 if (match) {
266 /* found a match */
267 psw = (const struct ip6protosw *)match->psw;
268 if (psw && psw->pr_input) {
269 encap_fillarg(m, match);
270 return (*psw->pr_input)(mp, offp, proto);
271 } else {
272 m_freem(m);
273 return IPPROTO_DONE;
274 }
275 }
276
277 /* last resort: inject to raw socket */
278 return rip6_input(mp, offp, proto);
279}
280#endif
281
282static void
283encap_add(ep)
284 struct encaptab *ep;
285{
286
287 LIST_INSERT_HEAD(&encaptab, ep, chain);
288}
289
290/*
291 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
292 * length of mask (sm and dm) is assumed to be same as sp/dp.
293 * Return value will be necessary as input (cookie) for encap_detach().
294 */
295const struct encaptab *
296encap_attach(af, proto, sp, sm, dp, dm, psw, arg)
297 int af;
298 int proto;
299 const struct sockaddr *sp, *sm;
300 const struct sockaddr *dp, *dm;
301 const struct protosw *psw;
302 void *arg;
303{
304 struct encaptab *ep;
305 int error;
306 int s;
307
308 s = splnet();
309 /* sanity check on args */
310 if (sp->sa_len > sizeof(ep->src) || dp->sa_len > sizeof(ep->dst)) {
311 error = EINVAL;
312 goto fail;
313 }
314 if (sp->sa_len != dp->sa_len) {
315 error = EINVAL;
316 goto fail;
317 }
318 if (af != sp->sa_family || af != dp->sa_family) {
319 error = EINVAL;
320 goto fail;
321 }
322
323 /* check if anyone have already attached with exactly same config */
324 LIST_FOREACH(ep, &encaptab, chain) {
325 if (ep->af != af)
326 continue;
327 if (ep->proto != proto)
328 continue;
329 if (ep->src.ss_len != sp->sa_len ||
330 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
331 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
332 continue;
333 if (ep->dst.ss_len != dp->sa_len ||
334 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
335 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
336 continue;
337
338 error = EEXIST;
339 goto fail;
340 }
341
342 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
343 if (ep == NULL) {
344 error = ENOBUFS;
345 goto fail;
346 }
347 bzero(ep, sizeof(*ep));
348
349 ep->af = af;
350 ep->proto = proto;
351 bcopy(sp, &ep->src, sp->sa_len);
352 bcopy(sm, &ep->srcmask, sp->sa_len);
353 bcopy(dp, &ep->dst, dp->sa_len);
354 bcopy(dm, &ep->dstmask, dp->sa_len);
355 ep->psw = psw;
356 ep->arg = arg;
357
358 encap_add(ep);
359
360 error = 0;
361 splx(s);
362 return ep;
363
364fail:
365 splx(s);
366 return NULL;
367}
368
369const struct encaptab *
370encap_attach_func(af, proto, func, psw, arg)
371 int af;
372 int proto;
373 int (*func)(const struct mbuf *, int, int, void *);
374 const struct protosw *psw;
375 void *arg;
376{
377 struct encaptab *ep;
378 int error;
379 int s;
380
381 s = splnet();
382 /* sanity check on args */
383 if (!func) {
384 error = EINVAL;
385 goto fail;
386 }
387
388 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
389 if (ep == NULL) {
390 error = ENOBUFS;
391 goto fail;
392 }
393 bzero(ep, sizeof(*ep));
394
395 ep->af = af;
396 ep->proto = proto;
397 ep->func = func;
398 ep->psw = psw;
399 ep->arg = arg;
400
401 encap_add(ep);
402
403 error = 0;
404 splx(s);
405 return ep;
406
407fail:
408 splx(s);
409 return NULL;
410}
411
412int
413encap_detach(cookie)
414 const struct encaptab *cookie;
415{
416 const struct encaptab *ep = cookie;
417 struct encaptab *p;
418
419 LIST_FOREACH(p, &encaptab, chain) {
420 if (p == ep) {
421 LIST_REMOVE(p, chain);
422 free(p, M_NETADDR); /*XXX*/
423 return 0;
424 }
425 }
426
427 return EINVAL;
428}
429
430static int
431mask_match(ep, sp, dp)
432 const struct encaptab *ep;
433 const struct sockaddr *sp;
434 const struct sockaddr *dp;
435{
436 struct sockaddr_storage s;
437 struct sockaddr_storage d;
438 int i;
439 const u_int8_t *p, *q;
440 u_int8_t *r;
441 int matchlen;
442
443 if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
444 return 0;
445 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
446 return 0;
447 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
448 return 0;
449
450 matchlen = 0;
451
452 p = (const u_int8_t *)sp;
453 q = (const u_int8_t *)&ep->srcmask;
454 r = (u_int8_t *)&s;
455 for (i = 0 ; i < sp->sa_len; i++) {
456 r[i] = p[i] & q[i];
457 /* XXX estimate */
458 matchlen += (q[i] ? 8 : 0);
459 }
460
461 p = (const u_int8_t *)dp;
462 q = (const u_int8_t *)&ep->dstmask;
463 r = (u_int8_t *)&d;
464 for (i = 0 ; i < dp->sa_len; i++) {
465 r[i] = p[i] & q[i];
466 /* XXX rough estimate */
467 matchlen += (q[i] ? 8 : 0);
468 }
469
470 /* need to overwrite len/family portion as we don't compare them */
471 s.ss_len = sp->sa_len;
472 s.ss_family = sp->sa_family;
473 d.ss_len = dp->sa_len;
474 d.ss_family = dp->sa_family;
475
476 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
477 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
478 return matchlen;
479 } else
480 return 0;
481}
482
483static void
484encap_fillarg(m, ep)
485 struct mbuf *m;
486 const struct encaptab *ep;
487{
|