1 /* $FreeBSD: releng/5.2/sys/netinet/ip_encap.c 115612 2003-06-01 09:20:38Z phk $ */
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>
94 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
95
96 static void encap_add(struct encaptab *);
97 static int mask_match(const struct encaptab *, const struct sockaddr *,
98 const struct sockaddr *);
99 static void encap_fillarg(struct mbuf *, const struct encaptab *);
100
101 #ifndef LIST_HEAD_INITIALIZER
102 /* rely upon BSS initialization */
103 LIST_HEAD(, encaptab) encaptab;
104 #else
105 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
106 #endif
107
108 void
109 encap_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
129 void
130 encap4_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
214 int
215 encap6_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
282 /*lint -sem(encap_add, custodial(1)) */
283 static void
284 encap_add(ep)
285 struct encaptab *ep;
286 {
287
288 LIST_INSERT_HEAD(&encaptab, ep, chain);
289 }
290
291 /*
292 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
293 * length of mask (sm and dm) is assumed to be same as sp/dp.
294 * Return value will be necessary as input (cookie) for encap_detach().
295 */
296 const struct encaptab *
297 encap_attach(af, proto, sp, sm, dp, dm, psw, arg)
298 int af;
299 int proto;
300 const struct sockaddr *sp, *sm;
301 const struct sockaddr *dp, *dm;
302 const struct protosw *psw;
303 void *arg;
304 {
305 struct encaptab *ep;
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 goto fail;
312 }
313 if (sp->sa_len != dp->sa_len) {
314 goto fail;
315 }
316 if (af != sp->sa_family || af != dp->sa_family) {
317 goto fail;
318 }
319
320 /* check if anyone have already attached with exactly same config */
321 LIST_FOREACH(ep, &encaptab, chain) {
322 if (ep->af != af)
323 continue;
324 if (ep->proto != proto)
325 continue;
326 if (ep->src.ss_len != sp->sa_len ||
327 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
328 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
329 continue;
330 if (ep->dst.ss_len != dp->sa_len ||
331 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
332 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
333 continue;
334
335 goto fail;
336 }
337
338 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
339 if (ep == NULL) {
340 goto fail;
341 }
342 bzero(ep, sizeof(*ep));
343
344 ep->af = af;
345 ep->proto = proto;
346 bcopy(sp, &ep->src, sp->sa_len);
347 bcopy(sm, &ep->srcmask, sp->sa_len);
348 bcopy(dp, &ep->dst, dp->sa_len);
349 bcopy(dm, &ep->dstmask, dp->sa_len);
350 ep->psw = psw;
351 ep->arg = arg;
352
353 encap_add(ep);
354
355 splx(s);
356 return ep;
357
358 fail:
359 splx(s);
360 return NULL;
361 }
362
363 const struct encaptab *
364 encap_attach_func(af, proto, func, psw, arg)
365 int af;
366 int proto;
367 int (*func)(const struct mbuf *, int, int, void *);
368 const struct protosw *psw;
369 void *arg;
370 {
371 struct encaptab *ep;
372 int s;
373
374 s = splnet();
375 /* sanity check on args */
376 if (!func)
377 goto fail;
378
379 ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
380 if (ep == NULL)
381 goto fail;
382 bzero(ep, sizeof(*ep));
383
384 ep->af = af;
385 ep->proto = proto;
386 ep->func = func;
387 ep->psw = psw;
388 ep->arg = arg;
389
390 encap_add(ep);
391
392 splx(s);
393 return ep;
394
395 fail:
396 splx(s);
397 return NULL;
398 }
399
400 int
401 encap_detach(cookie)
402 const struct encaptab *cookie;
403 {
404 const struct encaptab *ep = cookie;
405 struct encaptab *p;
406
407 LIST_FOREACH(p, &encaptab, chain) {
408 if (p == ep) {
409 LIST_REMOVE(p, chain);
410 free(p, M_NETADDR); /*XXX*/
411 return 0;
412 }
413 }
414
415 return EINVAL;
416 }
417
418 static int
419 mask_match(ep, sp, dp)
420 const struct encaptab *ep;
421 const struct sockaddr *sp;
422 const struct sockaddr *dp;
423 {
424 struct sockaddr_storage s;
425 struct sockaddr_storage d;
426 int i;
427 const u_int8_t *p, *q;
428 u_int8_t *r;
429 int matchlen;
430
431 if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
432 return 0;
433 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
434 return 0;
435 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
436 return 0;
437
438 matchlen = 0;
439
440 p = (const u_int8_t *)sp;
441 q = (const u_int8_t *)&ep->srcmask;
442 r = (u_int8_t *)&s;
443 for (i = 0 ; i < sp->sa_len; i++) {
444 r[i] = p[i] & q[i];
445 /* XXX estimate */
446 matchlen += (q[i] ? 8 : 0);
447 }
448
449 p = (const u_int8_t *)dp;
450 q = (const u_int8_t *)&ep->dstmask;
451 r = (u_int8_t *)&d;
452 for (i = 0 ; i < dp->sa_len; i++) {
453 r[i] = p[i] & q[i];
454 /* XXX rough estimate */
455 matchlen += (q[i] ? 8 : 0);
456 }
457
458 /* need to overwrite len/family portion as we don't compare them */
459 s.ss_len = sp->sa_len;
460 s.ss_family = sp->sa_family;
461 d.ss_len = dp->sa_len;
462 d.ss_family = dp->sa_family;
463
464 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
465 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
466 return matchlen;
467 } else
468 return 0;
469 }
470
471 static void
472 encap_fillarg(m, ep)
473 struct mbuf *m;
474 const struct encaptab *ep;
475 {
476 struct m_tag *tag;
477
478 tag = m_tag_get(PACKET_TAG_ENCAP, sizeof (void*), M_NOWAIT);
479 if (tag) {
480 *(void**)(tag+1) = ep->arg;
481 m_tag_prepend(m, tag);
482 }
483 }
484
485 void *
486 encap_getarg(m)
487 struct mbuf *m;
488 {
489 void *p = NULL;
490 struct m_tag *tag;
491
492 tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
493 if (tag) {
494 p = *(void**)(tag+1);
495 m_tag_delete(m, tag);
496 }
497 return p;
498 }
Cache object: a8671e2274b18fe4090edc17099f972f
|