xref: /netbsd-src/sys/netinet/ip_encap.c (revision f89f6560d453f5e37386cc7938c072d2f528b9fa)
1 /*	$NetBSD: ip_encap.c,v 1.44 2015/04/16 06:50:16 ozaki-r Exp $	*/
2 /*	$KAME: ip_encap.c,v 1.73 2001/10/02 08:30:58 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  *	RFC3056 6to4 tunnel
43  *	isatap tunnel
44  *	mobile-ip6 (uses RFC2473)
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 /*
61  * With USE_RADIX the code will use radix table for tunnel lookup, for
62  * tunnels registered with encap_attach() with a addr/mask pair.
63  * Faster on machines with thousands of tunnel registerations (= interfaces).
64  *
65  * The code assumes that radix table code can handle non-continuous netmask,
66  * as it will pass radix table memory region with (src + dst) sockaddr pair.
67  *
68  * FreeBSD is excluded here as they make max_keylen a static variable, and
69  * thus forbid definition of radix table other than proper domains.
70  *
71  * !!!!!!!
72  * !!NOTE: dom_maxrtkey assumes USE_RADIX is defined.
73  * !!!!!!!
74  */
75 #define USE_RADIX
76 
77 #include <sys/cdefs.h>
78 __KERNEL_RCSID(0, "$NetBSD: ip_encap.c,v 1.44 2015/04/16 06:50:16 ozaki-r Exp $");
79 
80 #include "opt_mrouting.h"
81 #include "opt_inet.h"
82 
83 #include <sys/param.h>
84 #include <sys/systm.h>
85 #include <sys/socket.h>
86 #include <sys/sockio.h>
87 #include <sys/mbuf.h>
88 #include <sys/errno.h>
89 #include <sys/protosw.h>
90 #include <sys/queue.h>
91 
92 #include <net/if.h>
93 #include <net/route.h>
94 
95 #include <netinet/in.h>
96 #include <netinet/in_systm.h>
97 #include <netinet/ip.h>
98 #include <netinet/ip_var.h>
99 #include <netinet/ip_encap.h>
100 #ifdef MROUTING
101 #include <netinet/ip_mroute.h>
102 #endif /* MROUTING */
103 
104 #ifdef INET6
105 #include <netinet/ip6.h>
106 #include <netinet6/ip6_var.h>
107 #include <netinet6/ip6protosw.h>
108 #include <netinet6/in6_var.h>
109 #include <netinet6/in6_pcb.h>
110 #include <netinet/icmp6.h>
111 #endif
112 
113 #include <net/net_osdep.h>
114 
115 enum direction { INBOUND, OUTBOUND };
116 
117 #ifdef INET
118 static struct encaptab *encap4_lookup(struct mbuf *, int, int, enum direction);
119 #endif
120 #ifdef INET6
121 static struct encaptab *encap6_lookup(struct mbuf *, int, int, enum direction);
122 #endif
123 static int encap_add(struct encaptab *);
124 static int encap_remove(struct encaptab *);
125 static int encap_afcheck(int, const struct sockaddr *, const struct sockaddr *);
126 #ifdef USE_RADIX
127 static struct radix_node_head *encap_rnh(int);
128 static int mask_matchlen(const struct sockaddr *);
129 #endif
130 #ifndef USE_RADIX
131 static int mask_match(const struct encaptab *, const struct sockaddr *,
132 		const struct sockaddr *);
133 #endif
134 static void encap_fillarg(struct mbuf *, const struct encaptab *);
135 
136 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
137 
138 #ifdef USE_RADIX
139 extern int max_keylen;	/* radix.c */
140 struct radix_node_head *encap_head[2];	/* 0 for AF_INET, 1 for AF_INET6 */
141 #endif
142 
143 void
144 encap_init(void)
145 {
146 	static int initialized = 0;
147 
148 	if (initialized)
149 		return;
150 	initialized++;
151 #if 0
152 	/*
153 	 * we cannot use LIST_INIT() here, since drivers may want to call
154 	 * encap_attach(), on driver attach.  encap_init() will be called
155 	 * on AF_INET{,6} initialization, which happens after driver
156 	 * initialization - using LIST_INIT() here can nuke encap_attach()
157 	 * from drivers.
158 	 */
159 	LIST_INIT(&encaptab);
160 #endif
161 
162 #ifdef USE_RADIX
163 	/*
164 	 * initialize radix lookup table when the radix subsystem is inited.
165 	 */
166 	rn_delayedinit((void *)&encap_head[0],
167 	    sizeof(struct sockaddr_pack) << 3);
168 #ifdef INET6
169 	rn_delayedinit((void *)&encap_head[1],
170 	    sizeof(struct sockaddr_pack) << 3);
171 #endif
172 #endif
173 }
174 
175 #ifdef INET
176 static struct encaptab *
177 encap4_lookup(struct mbuf *m, int off, int proto, enum direction dir)
178 {
179 	struct ip *ip;
180 	struct ip_pack4 pack;
181 	struct encaptab *ep, *match;
182 	int prio, matchprio;
183 #ifdef USE_RADIX
184 	struct radix_node_head *rnh = encap_rnh(AF_INET);
185 	struct radix_node *rn;
186 #endif
187 
188 	KASSERT(m->m_len >= sizeof(*ip));
189 
190 	ip = mtod(m, struct ip *);
191 
192 	memset(&pack, 0, sizeof(pack));
193 	pack.p.sp_len = sizeof(pack);
194 	pack.mine.sin_family = pack.yours.sin_family = AF_INET;
195 	pack.mine.sin_len = pack.yours.sin_len = sizeof(struct sockaddr_in);
196 	if (dir == INBOUND) {
197 		pack.mine.sin_addr = ip->ip_dst;
198 		pack.yours.sin_addr = ip->ip_src;
199 	} else {
200 		pack.mine.sin_addr = ip->ip_src;
201 		pack.yours.sin_addr = ip->ip_dst;
202 	}
203 
204 	match = NULL;
205 	matchprio = 0;
206 
207 #ifdef USE_RADIX
208 	rn = rnh->rnh_matchaddr((void *)&pack, rnh);
209 	if (rn && (rn->rn_flags & RNF_ROOT) == 0) {
210 		match = (struct encaptab *)rn;
211 		matchprio = mask_matchlen(match->srcmask) +
212 		    mask_matchlen(match->dstmask);
213 	}
214 #endif
215 
216 	LIST_FOREACH(ep, &encaptab, chain) {
217 		if (ep->af != AF_INET)
218 			continue;
219 		if (ep->proto >= 0 && ep->proto != proto)
220 			continue;
221 		if (ep->func)
222 			prio = (*ep->func)(m, off, proto, ep->arg);
223 		else {
224 #ifdef USE_RADIX
225 			continue;
226 #else
227 			prio = mask_match(ep, (struct sockaddr *)&pack.mine,
228 			    (struct sockaddr *)&pack.yours);
229 #endif
230 		}
231 
232 		/*
233 		 * We prioritize the matches by using bit length of the
234 		 * matches.  mask_match() and user-supplied matching function
235 		 * should return the bit length of the matches (for example,
236 		 * if both src/dst are matched for IPv4, 64 should be returned).
237 		 * 0 or negative return value means "it did not match".
238 		 *
239 		 * The question is, since we have two "mask" portion, we
240 		 * cannot really define total order between entries.
241 		 * For example, which of these should be preferred?
242 		 * mask_match() returns 48 (32 + 16) for both of them.
243 		 *	src=3ffe::/16, dst=3ffe:501::/32
244 		 *	src=3ffe:501::/32, dst=3ffe::/16
245 		 *
246 		 * We need to loop through all the possible candidates
247 		 * to get the best match - the search takes O(n) for
248 		 * n attachments (i.e. interfaces).
249 		 *
250 		 * For radix-based lookup, I guess source takes precedence.
251 		 * See rn_{refines,lexobetter} for the correct answer.
252 		 */
253 		if (prio <= 0)
254 			continue;
255 		if (prio > matchprio) {
256 			matchprio = prio;
257 			match = ep;
258 		}
259 	}
260 
261 	return match;
262 }
263 
264 void
265 encap4_input(struct mbuf *m, ...)
266 {
267 	int off, proto;
268 	va_list ap;
269 	const struct protosw *psw;
270 	struct encaptab *match;
271 
272 	va_start(ap, m);
273 	off = va_arg(ap, int);
274 	proto = va_arg(ap, int);
275 	va_end(ap);
276 
277 	match = encap4_lookup(m, off, proto, INBOUND);
278 
279 	if (match) {
280 		/* found a match, "match" has the best one */
281 		psw = match->psw;
282 		if (psw && psw->pr_input) {
283 			encap_fillarg(m, match);
284 			(*psw->pr_input)(m, off, proto);
285 		} else
286 			m_freem(m);
287 		return;
288 	}
289 
290 	/* last resort: inject to raw socket */
291 	rip_input(m, off, proto);
292 }
293 #endif
294 
295 #ifdef INET6
296 static struct encaptab *
297 encap6_lookup(struct mbuf *m, int off, int proto, enum direction dir)
298 {
299 	struct ip6_hdr *ip6;
300 	struct ip_pack6 pack;
301 	int prio, matchprio;
302 	struct encaptab *ep, *match;
303 #ifdef USE_RADIX
304 	struct radix_node_head *rnh = encap_rnh(AF_INET6);
305 	struct radix_node *rn;
306 #endif
307 
308 	KASSERT(m->m_len >= sizeof(*ip6));
309 
310 	ip6 = mtod(m, struct ip6_hdr *);
311 
312 	memset(&pack, 0, sizeof(pack));
313 	pack.p.sp_len = sizeof(pack);
314 	pack.mine.sin6_family = pack.yours.sin6_family = AF_INET6;
315 	pack.mine.sin6_len = pack.yours.sin6_len = sizeof(struct sockaddr_in6);
316 	if (dir == INBOUND) {
317 		pack.mine.sin6_addr = ip6->ip6_dst;
318 		pack.yours.sin6_addr = ip6->ip6_src;
319 	} else {
320 		pack.mine.sin6_addr = ip6->ip6_src;
321 		pack.yours.sin6_addr = ip6->ip6_dst;
322 	}
323 
324 	match = NULL;
325 	matchprio = 0;
326 
327 #ifdef USE_RADIX
328 	rn = rnh->rnh_matchaddr((void *)&pack, rnh);
329 	if (rn && (rn->rn_flags & RNF_ROOT) == 0) {
330 		match = (struct encaptab *)rn;
331 		matchprio = mask_matchlen(match->srcmask) +
332 		    mask_matchlen(match->dstmask);
333 	}
334 #endif
335 
336 	LIST_FOREACH(ep, &encaptab, chain) {
337 		if (ep->af != AF_INET6)
338 			continue;
339 		if (ep->proto >= 0 && ep->proto != proto)
340 			continue;
341 		if (ep->func)
342 			prio = (*ep->func)(m, off, proto, ep->arg);
343 		else {
344 #ifdef USE_RADIX
345 			continue;
346 #else
347 			prio = mask_match(ep, (struct sockaddr *)&pack.mine,
348 			    (struct sockaddr *)&pack.yours);
349 #endif
350 		}
351 
352 		/* see encap4_lookup() for issues here */
353 		if (prio <= 0)
354 			continue;
355 		if (prio > matchprio) {
356 			matchprio = prio;
357 			match = ep;
358 		}
359 	}
360 
361 	return match;
362 }
363 
364 int
365 encap6_input(struct mbuf **mp, int *offp, int proto)
366 {
367 	struct mbuf *m = *mp;
368 	const struct ip6protosw *psw;
369 	struct encaptab *match;
370 
371 	match = encap6_lookup(m, *offp, proto, INBOUND);
372 
373 	if (match) {
374 		/* found a match */
375 		psw = (const struct ip6protosw *)match->psw;
376 		if (psw && psw->pr_input) {
377 			encap_fillarg(m, match);
378 			return (*psw->pr_input)(mp, offp, proto);
379 		} else {
380 			m_freem(m);
381 			return IPPROTO_DONE;
382 		}
383 	}
384 
385 	/* last resort: inject to raw socket */
386 	return rip6_input(mp, offp, proto);
387 }
388 #endif
389 
390 static int
391 encap_add(struct encaptab *ep)
392 {
393 #ifdef USE_RADIX
394 	struct radix_node_head *rnh = encap_rnh(ep->af);
395 #endif
396 	int error = 0;
397 
398 	LIST_INSERT_HEAD(&encaptab, ep, chain);
399 #ifdef USE_RADIX
400 	if (!ep->func && rnh) {
401 		if (!rnh->rnh_addaddr((void *)ep->addrpack,
402 		    (void *)ep->maskpack, rnh, ep->nodes)) {
403 			error = EEXIST;
404 			goto fail;
405 		}
406 	}
407 #endif
408 	return error;
409 
410  fail:
411 	LIST_REMOVE(ep, chain);
412 	return error;
413 }
414 
415 static int
416 encap_remove(struct encaptab *ep)
417 {
418 #ifdef USE_RADIX
419 	struct radix_node_head *rnh = encap_rnh(ep->af);
420 #endif
421 	int error = 0;
422 
423 	LIST_REMOVE(ep, chain);
424 #ifdef USE_RADIX
425 	if (!ep->func && rnh) {
426 		if (!rnh->rnh_deladdr((void *)ep->addrpack,
427 		    (void *)ep->maskpack, rnh))
428 			error = ESRCH;
429 	}
430 #endif
431 	return error;
432 }
433 
434 static int
435 encap_afcheck(int af, const struct sockaddr *sp, const struct sockaddr *dp)
436 {
437 	if (sp && dp) {
438 		if (sp->sa_len != dp->sa_len)
439 			return EINVAL;
440 		if (af != sp->sa_family || af != dp->sa_family)
441 			return EINVAL;
442 	} else if (!sp && !dp)
443 		;
444 	else
445 		return EINVAL;
446 
447 	switch (af) {
448 	case AF_INET:
449 		if (sp && sp->sa_len != sizeof(struct sockaddr_in))
450 			return EINVAL;
451 		if (dp && dp->sa_len != sizeof(struct sockaddr_in))
452 			return EINVAL;
453 		break;
454 #ifdef INET6
455 	case AF_INET6:
456 		if (sp && sp->sa_len != sizeof(struct sockaddr_in6))
457 			return EINVAL;
458 		if (dp && dp->sa_len != sizeof(struct sockaddr_in6))
459 			return EINVAL;
460 		break;
461 #endif
462 	default:
463 		return EAFNOSUPPORT;
464 	}
465 
466 	return 0;
467 }
468 
469 /*
470  * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
471  * length of mask (sm and dm) is assumed to be same as sp/dp.
472  * Return value will be necessary as input (cookie) for encap_detach().
473  */
474 const struct encaptab *
475 encap_attach(int af, int proto,
476     const struct sockaddr *sp, const struct sockaddr *sm,
477     const struct sockaddr *dp, const struct sockaddr *dm,
478     const struct protosw *psw, void *arg)
479 {
480 	struct encaptab *ep;
481 	int error;
482 	int s;
483 	size_t l;
484 	struct ip_pack4 *pack4;
485 #ifdef INET6
486 	struct ip_pack6 *pack6;
487 #endif
488 
489 	s = splsoftnet();
490 	/* sanity check on args */
491 	error = encap_afcheck(af, sp, dp);
492 	if (error)
493 		goto fail;
494 
495 	/* check if anyone have already attached with exactly same config */
496 	LIST_FOREACH(ep, &encaptab, chain) {
497 		if (ep->af != af)
498 			continue;
499 		if (ep->proto != proto)
500 			continue;
501 		if (ep->func)
502 			continue;
503 
504 		KASSERT(ep->src != NULL);
505 		KASSERT(ep->dst != NULL);
506 		KASSERT(ep->srcmask != NULL);
507 		KASSERT(ep->dstmask != NULL);
508 
509 		if (ep->src->sa_len != sp->sa_len ||
510 		    memcmp(ep->src, sp, sp->sa_len) != 0 ||
511 		    memcmp(ep->srcmask, sm, sp->sa_len) != 0)
512 			continue;
513 		if (ep->dst->sa_len != dp->sa_len ||
514 		    memcmp(ep->dst, dp, dp->sa_len) != 0 ||
515 		    memcmp(ep->dstmask, dm, dp->sa_len) != 0)
516 			continue;
517 
518 		error = EEXIST;
519 		goto fail;
520 	}
521 
522 	switch (af) {
523 	case AF_INET:
524 		l = sizeof(*pack4);
525 		break;
526 #ifdef INET6
527 	case AF_INET6:
528 		l = sizeof(*pack6);
529 		break;
530 #endif
531 	default:
532 		goto fail;
533 	}
534 
535 	/* M_NETADDR ok? */
536 	ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT|M_ZERO);
537 	if (ep == NULL) {
538 		error = ENOBUFS;
539 		goto fail;
540 	}
541 	ep->addrpack = malloc(l, M_NETADDR, M_NOWAIT|M_ZERO);
542 	if (ep->addrpack == NULL) {
543 		error = ENOBUFS;
544 		goto gc;
545 	}
546 	ep->maskpack = malloc(l, M_NETADDR, M_NOWAIT|M_ZERO);
547 	if (ep->maskpack == NULL) {
548 		error = ENOBUFS;
549 		goto gc;
550 	}
551 
552 	ep->af = af;
553 	ep->proto = proto;
554 	ep->addrpack->sa_len = l & 0xff;
555 	ep->maskpack->sa_len = l & 0xff;
556 	switch (af) {
557 	case AF_INET:
558 		pack4 = (struct ip_pack4 *)ep->addrpack;
559 		ep->src = (struct sockaddr *)&pack4->mine;
560 		ep->dst = (struct sockaddr *)&pack4->yours;
561 		pack4 = (struct ip_pack4 *)ep->maskpack;
562 		ep->srcmask = (struct sockaddr *)&pack4->mine;
563 		ep->dstmask = (struct sockaddr *)&pack4->yours;
564 		break;
565 #ifdef INET6
566 	case AF_INET6:
567 		pack6 = (struct ip_pack6 *)ep->addrpack;
568 		ep->src = (struct sockaddr *)&pack6->mine;
569 		ep->dst = (struct sockaddr *)&pack6->yours;
570 		pack6 = (struct ip_pack6 *)ep->maskpack;
571 		ep->srcmask = (struct sockaddr *)&pack6->mine;
572 		ep->dstmask = (struct sockaddr *)&pack6->yours;
573 		break;
574 #endif
575 	}
576 
577 	memcpy(ep->src, sp, sp->sa_len);
578 	memcpy(ep->srcmask, sm, sp->sa_len);
579 	memcpy(ep->dst, dp, dp->sa_len);
580 	memcpy(ep->dstmask, dm, dp->sa_len);
581 	ep->psw = psw;
582 	ep->arg = arg;
583 
584 	error = encap_add(ep);
585 	if (error)
586 		goto gc;
587 
588 	error = 0;
589 	splx(s);
590 	return ep;
591 
592 gc:
593 	if (ep->addrpack)
594 		free(ep->addrpack, M_NETADDR);
595 	if (ep->maskpack)
596 		free(ep->maskpack, M_NETADDR);
597 	if (ep)
598 		free(ep, M_NETADDR);
599 fail:
600 	splx(s);
601 	return NULL;
602 }
603 
604 const struct encaptab *
605 encap_attach_func(int af, int proto,
606     int (*func)(struct mbuf *, int, int, void *),
607     const struct protosw *psw, void *arg)
608 {
609 	struct encaptab *ep;
610 	int error;
611 	int s;
612 
613 	s = splsoftnet();
614 	/* sanity check on args */
615 	if (!func) {
616 		error = EINVAL;
617 		goto fail;
618 	}
619 
620 	error = encap_afcheck(af, NULL, NULL);
621 	if (error)
622 		goto fail;
623 
624 	ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT);	/*XXX*/
625 	if (ep == NULL) {
626 		error = ENOBUFS;
627 		goto fail;
628 	}
629 	memset(ep, 0, sizeof(*ep));
630 
631 	ep->af = af;
632 	ep->proto = proto;
633 	ep->func = func;
634 	ep->psw = psw;
635 	ep->arg = arg;
636 
637 	error = encap_add(ep);
638 	if (error)
639 		goto fail;
640 
641 	error = 0;
642 	splx(s);
643 	return ep;
644 
645 fail:
646 	splx(s);
647 	return NULL;
648 }
649 
650 /* XXX encap4_ctlinput() is necessary if we set DF=1 on outer IPv4 header */
651 
652 #ifdef INET6
653 void *
654 encap6_ctlinput(int cmd, const struct sockaddr *sa, void *d0)
655 {
656 	void *d = d0;
657 	struct ip6_hdr *ip6;
658 	struct mbuf *m;
659 	int off;
660 	struct ip6ctlparam *ip6cp = NULL;
661 	int nxt;
662 	struct encaptab *ep;
663 	const struct ip6protosw *psw;
664 
665 	if (sa->sa_family != AF_INET6 ||
666 	    sa->sa_len != sizeof(struct sockaddr_in6))
667 		return NULL;
668 
669 	if ((unsigned)cmd >= PRC_NCMDS)
670 		return NULL;
671 	if (cmd == PRC_HOSTDEAD)
672 		d = NULL;
673 	else if (cmd == PRC_MSGSIZE)
674 		; /* special code is present, see below */
675 	else if (inet6ctlerrmap[cmd] == 0)
676 		return NULL;
677 
678 	/* if the parameter is from icmp6, decode it. */
679 	if (d != NULL) {
680 		ip6cp = (struct ip6ctlparam *)d;
681 		m = ip6cp->ip6c_m;
682 		ip6 = ip6cp->ip6c_ip6;
683 		off = ip6cp->ip6c_off;
684 		nxt = ip6cp->ip6c_nxt;
685 
686 		if (ip6 && cmd == PRC_MSGSIZE) {
687 			int valid = 0;
688 			struct encaptab *match;
689 
690 			/*
691 		 	* Check to see if we have a valid encap configuration.
692 		 	*/
693 			match = encap6_lookup(m, off, nxt, OUTBOUND);
694 			if (match)
695 				valid++;
696 
697 			/*
698 		 	* Depending on the value of "valid" and routing table
699 		 	* size (mtudisc_{hi,lo}wat), we will:
700 		 	* - recalcurate the new MTU and create the
701 		 	*   corresponding routing entry, or
702 		 	* - ignore the MTU change notification.
703 		 	*/
704 			icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
705 		}
706 	} else {
707 		m = NULL;
708 		ip6 = NULL;
709 		nxt = -1;
710 	}
711 
712 	/* inform all listeners */
713 	LIST_FOREACH(ep, &encaptab, chain) {
714 		if (ep->af != AF_INET6)
715 			continue;
716 		if (ep->proto >= 0 && ep->proto != nxt)
717 			continue;
718 
719 		/* should optimize by looking at address pairs */
720 
721 		/* XXX need to pass ep->arg or ep itself to listeners */
722 		psw = (const struct ip6protosw *)ep->psw;
723 		if (psw && psw->pr_ctlinput)
724 			(*psw->pr_ctlinput)(cmd, sa, d);
725 	}
726 
727 	rip6_ctlinput(cmd, sa, d0);
728 	return NULL;
729 }
730 #endif
731 
732 int
733 encap_detach(const struct encaptab *cookie)
734 {
735 	const struct encaptab *ep = cookie;
736 	struct encaptab *p, *np;
737 	int error;
738 
739 	LIST_FOREACH_SAFE(p, &encaptab, chain, np) {
740 		if (p == ep) {
741 			error = encap_remove(p);
742 			if (error)
743 				return error;
744 			if (!ep->func) {
745 				free(p->addrpack, M_NETADDR);
746 				free(p->maskpack, M_NETADDR);
747 			}
748 			free(p, M_NETADDR);	/*XXX*/
749 			return 0;
750 		}
751 	}
752 
753 	return ENOENT;
754 }
755 
756 #ifdef USE_RADIX
757 static struct radix_node_head *
758 encap_rnh(int af)
759 {
760 
761 	switch (af) {
762 	case AF_INET:
763 		return encap_head[0];
764 #ifdef INET6
765 	case AF_INET6:
766 		return encap_head[1];
767 #endif
768 	default:
769 		return NULL;
770 	}
771 }
772 
773 static int
774 mask_matchlen(const struct sockaddr *sa)
775 {
776 	const char *p, *ep;
777 	int l;
778 
779 	p = (const char *)sa;
780 	ep = p + sa->sa_len;
781 	p += 2;	/* sa_len + sa_family */
782 
783 	l = 0;
784 	while (p < ep) {
785 		l += (*p ? 8 : 0);	/* estimate */
786 		p++;
787 	}
788 	return l;
789 }
790 #endif
791 
792 #ifndef USE_RADIX
793 static int
794 mask_match(const struct encaptab *ep,
795 	   const struct sockaddr *sp,
796 	   const struct sockaddr *dp)
797 {
798 	struct sockaddr_storage s;
799 	struct sockaddr_storage d;
800 	int i;
801 	const u_int8_t *p, *q;
802 	u_int8_t *r;
803 	int matchlen;
804 
805 	KASSERTMSG(ep->func == NULL, "wrong encaptab passed to mask_match");
806 
807 	if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
808 		return 0;
809 	if (sp->sa_family != ep->af || dp->sa_family != ep->af)
810 		return 0;
811 	if (sp->sa_len != ep->src->sa_len || dp->sa_len != ep->dst->sa_len)
812 		return 0;
813 
814 	matchlen = 0;
815 
816 	p = (const u_int8_t *)sp;
817 	q = (const u_int8_t *)ep->srcmask;
818 	r = (u_int8_t *)&s;
819 	for (i = 0 ; i < sp->sa_len; i++) {
820 		r[i] = p[i] & q[i];
821 		/* XXX estimate */
822 		matchlen += (q[i] ? 8 : 0);
823 	}
824 
825 	p = (const u_int8_t *)dp;
826 	q = (const u_int8_t *)ep->dstmask;
827 	r = (u_int8_t *)&d;
828 	for (i = 0 ; i < dp->sa_len; i++) {
829 		r[i] = p[i] & q[i];
830 		/* XXX rough estimate */
831 		matchlen += (q[i] ? 8 : 0);
832 	}
833 
834 	/* need to overwrite len/family portion as we don't compare them */
835 	s.ss_len = sp->sa_len;
836 	s.ss_family = sp->sa_family;
837 	d.ss_len = dp->sa_len;
838 	d.ss_family = dp->sa_family;
839 
840 	if (memcmp(&s, ep->src, ep->src->sa_len) == 0 &&
841 	    memcmp(&d, ep->dst, ep->dst->sa_len) == 0) {
842 		return matchlen;
843 	} else
844 		return 0;
845 }
846 #endif
847 
848 static void
849 encap_fillarg(struct mbuf *m, const struct encaptab *ep)
850 {
851 	struct m_tag *mtag;
852 
853 	mtag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), M_NOWAIT);
854 	if (mtag) {
855 		*(void **)(mtag + 1) = ep->arg;
856 		m_tag_prepend(m, mtag);
857 	}
858 }
859 
860 void *
861 encap_getarg(struct mbuf *m)
862 {
863 	void *p;
864 	struct m_tag *mtag;
865 
866 	p = NULL;
867 	mtag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
868 	if (mtag != NULL) {
869 		p = *(void **)(mtag + 1);
870 		m_tag_delete(m, mtag);
871 	}
872 	return p;
873 }
874