xref: /netbsd-src/sys/netinet/ip_encap.c (revision 404fbe5fb94ca1e054339640cabb2801ce52dd30)
1 /*	$KAME: ip_encap.c,v 1.73 2001/10/02 08:30:58 itojun Exp $	*/
2 
3 /*
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 /*
32  * My grandfather said that there's a devil inside tunnelling technology...
33  *
34  * We have surprisingly many protocols that want packets with IP protocol
35  * #4 or #41.  Here's a list of protocols that want protocol #41:
36  *	RFC1933 configured tunnel
37  *	RFC1933 automatic tunnel
38  *	RFC2401 IPsec tunnel
39  *	RFC2473 IPv6 generic packet tunnelling
40  *	RFC2529 6over4 tunnel
41  *	RFC3056 6to4 tunnel
42  *	isatap tunnel
43  *	mobile-ip6 (uses RFC2473)
44  * Here's a list of protocol that want protocol #4:
45  *	RFC1853 IPv4-in-IPv4 tunnelling
46  *	RFC2003 IPv4 encapsulation within IPv4
47  *	RFC2344 reverse tunnelling for mobile-ip4
48  *	RFC2401 IPsec tunnel
49  * Well, what can I say.  They impose different en/decapsulation mechanism
50  * from each other, so they need separate protocol handler.  The only one
51  * we can easily determine by protocol # is IPsec, which always has
52  * AH/ESP/IPComp header right after outer IP header.
53  *
54  * So, clearly good old protosw does not work for protocol #4 and #41.
55  * The code will let you match protocol via src/dst address pair.
56  */
57 /* XXX is M_NETADDR correct? */
58 
59 /*
60  * With USE_RADIX the code will use radix table for tunnel lookup, for
61  * tunnels registered with encap_attach() with a addr/mask pair.
62  * Faster on machines with thousands of tunnel registerations (= interfaces).
63  *
64  * The code assumes that radix table code can handle non-continuous netmask,
65  * as it will pass radix table memory region with (src + dst) sockaddr pair.
66  *
67  * FreeBSD is excluded here as they make max_keylen a static variable, and
68  * thus forbid definition of radix table other than proper domains.
69  *
70  * !!!!!!!
71  * !!NOTE: dom_maxrtkey assumes USE_RADIX is defined.
72  * !!!!!!!
73  */
74 #define USE_RADIX
75 
76 #include <sys/cdefs.h>
77 __KERNEL_RCSID(0, "$NetBSD: ip_encap.c,v 1.33 2008/11/25 18:28:05 pooka Exp $");
78 
79 #include "opt_mrouting.h"
80 #include "opt_inet.h"
81 
82 #include <sys/param.h>
83 #include <sys/systm.h>
84 #include <sys/socket.h>
85 #include <sys/sockio.h>
86 #include <sys/mbuf.h>
87 #include <sys/errno.h>
88 #include <sys/protosw.h>
89 #include <sys/queue.h>
90 
91 #include <net/if.h>
92 #include <net/route.h>
93 
94 #include <netinet/in.h>
95 #include <netinet/in_systm.h>
96 #include <netinet/ip.h>
97 #include <netinet/ip_var.h>
98 #include <netinet/ip_encap.h>
99 #ifdef MROUTING
100 #include <netinet/ip_mroute.h>
101 #endif /* MROUTING */
102 
103 #ifdef INET6
104 #include <netinet/ip6.h>
105 #include <netinet6/ip6_var.h>
106 #include <netinet6/ip6protosw.h>
107 #include <netinet6/in6_var.h>
108 #include <netinet6/in6_pcb.h>
109 #include <netinet/icmp6.h>
110 #endif
111 
112 #include <machine/stdarg.h>
113 
114 #include <net/net_osdep.h>
115 
116 enum direction { INBOUND, OUTBOUND };
117 
118 #ifdef INET
119 static struct encaptab *encap4_lookup(struct mbuf *, int, int, enum direction);
120 #endif
121 #ifdef INET6
122 static struct encaptab *encap6_lookup(struct mbuf *, int, int, enum direction);
123 #endif
124 static int encap_add(struct encaptab *);
125 static int encap_remove(struct encaptab *);
126 static int encap_afcheck(int, const struct sockaddr *, const struct sockaddr *);
127 #ifdef USE_RADIX
128 static struct radix_node_head *encap_rnh(int);
129 static int mask_matchlen(const struct sockaddr *);
130 #endif
131 #ifndef USE_RADIX
132 static int mask_match(const struct encaptab *, const struct sockaddr *,
133 		const struct sockaddr *);
134 #endif
135 static void encap_fillarg(struct mbuf *, const struct encaptab *);
136 
137 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
138 
139 #ifdef USE_RADIX
140 extern int max_keylen;	/* radix.c */
141 struct radix_node_head *encap_head[2];	/* 0 for AF_INET, 1 for AF_INET6 */
142 #endif
143 
144 void
145 encap_init(void)
146 {
147 	static int initialized = 0;
148 
149 	if (initialized)
150 		return;
151 	initialized++;
152 #if 0
153 	/*
154 	 * we cannot use LIST_INIT() here, since drivers may want to call
155 	 * encap_attach(), on driver attach.  encap_init() will be called
156 	 * on AF_INET{,6} initialization, which happens after driver
157 	 * initialization - using LIST_INIT() here can nuke encap_attach()
158 	 * from drivers.
159 	 */
160 	LIST_INIT(&encaptab);
161 #endif
162 
163 #ifdef USE_RADIX
164 	/*
165 	 * initialize radix lookup table.
166 	 * max_keylen initialization happen in the rn_init().
167 	 */
168 	rn_init();
169 	rn_inithead((void *)&encap_head[0], sizeof(struct sockaddr_pack) << 3);
170 #ifdef INET6
171 	rn_inithead((void *)&encap_head[1], sizeof(struct sockaddr_pack) << 3);
172 #endif
173 #endif
174 }
175 
176 #ifdef INET
177 static struct encaptab *
178 encap4_lookup(struct mbuf *m, int off, int proto, enum direction dir)
179 {
180 	struct ip *ip;
181 	struct ip_pack4 pack;
182 	struct encaptab *ep, *match;
183 	int prio, matchprio;
184 #ifdef USE_RADIX
185 	struct radix_node_head *rnh = encap_rnh(AF_INET);
186 	struct radix_node *rn;
187 #endif
188 
189 #ifdef DIAGNOSTIC
190 	if (m->m_len < sizeof(*ip))
191 		panic("encap4_lookup");
192 #endif
193 	ip = mtod(m, struct ip *);
194 
195 	bzero(&pack, sizeof(pack));
196 	pack.p.sp_len = sizeof(pack);
197 	pack.mine.sin_family = pack.yours.sin_family = AF_INET;
198 	pack.mine.sin_len = pack.yours.sin_len = sizeof(struct sockaddr_in);
199 	if (dir == INBOUND) {
200 		pack.mine.sin_addr = ip->ip_dst;
201 		pack.yours.sin_addr = ip->ip_src;
202 	} else {
203 		pack.mine.sin_addr = ip->ip_src;
204 		pack.yours.sin_addr = ip->ip_dst;
205 	}
206 
207 	match = NULL;
208 	matchprio = 0;
209 
210 #ifdef USE_RADIX
211 	rn = rnh->rnh_matchaddr((void *)&pack, rnh);
212 	if (rn && (rn->rn_flags & RNF_ROOT) == 0) {
213 		match = (struct encaptab *)rn;
214 		matchprio = mask_matchlen(match->srcmask) +
215 		    mask_matchlen(match->dstmask);
216 	}
217 #endif
218 
219 	LIST_FOREACH(ep, &encaptab, chain) {
220 		if (ep->af != AF_INET)
221 			continue;
222 		if (ep->proto >= 0 && ep->proto != proto)
223 			continue;
224 		if (ep->func)
225 			prio = (*ep->func)(m, off, proto, ep->arg);
226 		else {
227 #ifdef USE_RADIX
228 			continue;
229 #else
230 			prio = mask_match(ep, (struct sockaddr *)&pack.mine,
231 			    (struct sockaddr *)&pack.yours);
232 #endif
233 		}
234 
235 		/*
236 		 * We prioritize the matches by using bit length of the
237 		 * matches.  mask_match() and user-supplied matching function
238 		 * should return the bit length of the matches (for example,
239 		 * if both src/dst are matched for IPv4, 64 should be returned).
240 		 * 0 or negative return value means "it did not match".
241 		 *
242 		 * The question is, since we have two "mask" portion, we
243 		 * cannot really define total order between entries.
244 		 * For example, which of these should be preferred?
245 		 * mask_match() returns 48 (32 + 16) for both of them.
246 		 *	src=3ffe::/16, dst=3ffe:501::/32
247 		 *	src=3ffe:501::/32, dst=3ffe::/16
248 		 *
249 		 * We need to loop through all the possible candidates
250 		 * to get the best match - the search takes O(n) for
251 		 * n attachments (i.e. interfaces).
252 		 *
253 		 * For radix-based lookup, I guess source takes precedence.
254 		 * See rn_{refines,lexobetter} for the correct answer.
255 		 */
256 		if (prio <= 0)
257 			continue;
258 		if (prio > matchprio) {
259 			matchprio = prio;
260 			match = ep;
261 		}
262 	}
263 
264 	return match;
265 #undef s
266 #undef d
267 }
268 
269 void
270 encap4_input(struct mbuf *m, ...)
271 {
272 	int off, proto;
273 	va_list ap;
274 	const struct protosw *psw;
275 	struct encaptab *match;
276 
277 	va_start(ap, m);
278 	off = va_arg(ap, int);
279 	proto = va_arg(ap, int);
280 	va_end(ap);
281 
282 	match = encap4_lookup(m, off, proto, INBOUND);
283 
284 	if (match) {
285 		/* found a match, "match" has the best one */
286 		psw = match->psw;
287 		if (psw && psw->pr_input) {
288 			encap_fillarg(m, match);
289 			(*psw->pr_input)(m, off, proto);
290 		} else
291 			m_freem(m);
292 		return;
293 	}
294 
295 	/* last resort: inject to raw socket */
296 	rip_input(m, off, proto);
297 }
298 #endif
299 
300 #ifdef INET6
301 static struct encaptab *
302 encap6_lookup(struct mbuf *m, int off, int proto, enum direction dir)
303 {
304 	struct ip6_hdr *ip6;
305 	struct ip_pack6 pack;
306 	int prio, matchprio;
307 	struct encaptab *ep, *match;
308 #ifdef USE_RADIX
309 	struct radix_node_head *rnh = encap_rnh(AF_INET6);
310 	struct radix_node *rn;
311 #endif
312 
313 #ifdef DIAGNOSTIC
314 	if (m->m_len < sizeof(*ip6))
315 		panic("encap6_lookup");
316 #endif
317 	ip6 = mtod(m, struct ip6_hdr *);
318 
319 	bzero(&pack, sizeof(pack));
320 	pack.p.sp_len = sizeof(pack);
321 	pack.mine.sin6_family = pack.yours.sin6_family = AF_INET6;
322 	pack.mine.sin6_len = pack.yours.sin6_len = sizeof(struct sockaddr_in6);
323 	if (dir == INBOUND) {
324 		pack.mine.sin6_addr = ip6->ip6_dst;
325 		pack.yours.sin6_addr = ip6->ip6_src;
326 	} else {
327 		pack.mine.sin6_addr = ip6->ip6_src;
328 		pack.yours.sin6_addr = ip6->ip6_dst;
329 	}
330 
331 	match = NULL;
332 	matchprio = 0;
333 
334 #ifdef USE_RADIX
335 	rn = rnh->rnh_matchaddr((void *)&pack, rnh);
336 	if (rn && (rn->rn_flags & RNF_ROOT) == 0) {
337 		match = (struct encaptab *)rn;
338 		matchprio = mask_matchlen(match->srcmask) +
339 		    mask_matchlen(match->dstmask);
340 	}
341 #endif
342 
343 	LIST_FOREACH(ep, &encaptab, chain) {
344 		if (ep->af != AF_INET6)
345 			continue;
346 		if (ep->proto >= 0 && ep->proto != proto)
347 			continue;
348 		if (ep->func)
349 			prio = (*ep->func)(m, off, proto, ep->arg);
350 		else {
351 #ifdef USE_RADIX
352 			continue;
353 #else
354 			prio = mask_match(ep, (struct sockaddr *)&pack.mine,
355 			    (struct sockaddr *)&pack.yours);
356 #endif
357 		}
358 
359 		/* see encap4_lookup() for issues here */
360 		if (prio <= 0)
361 			continue;
362 		if (prio > matchprio) {
363 			matchprio = prio;
364 			match = ep;
365 		}
366 	}
367 
368 	return match;
369 #undef s
370 #undef d
371 }
372 
373 int
374 encap6_input(struct mbuf **mp, int *offp, int proto)
375 {
376 	struct mbuf *m = *mp;
377 	const struct ip6protosw *psw;
378 	struct encaptab *match;
379 
380 	match = encap6_lookup(m, *offp, proto, INBOUND);
381 
382 	if (match) {
383 		/* found a match */
384 		psw = (const struct ip6protosw *)match->psw;
385 		if (psw && psw->pr_input) {
386 			encap_fillarg(m, match);
387 			return (*psw->pr_input)(mp, offp, proto);
388 		} else {
389 			m_freem(m);
390 			return IPPROTO_DONE;
391 		}
392 	}
393 
394 	/* last resort: inject to raw socket */
395 	return rip6_input(mp, offp, proto);
396 }
397 #endif
398 
399 static int
400 encap_add(struct encaptab *ep)
401 {
402 #ifdef USE_RADIX
403 	struct radix_node_head *rnh = encap_rnh(ep->af);
404 #endif
405 	int error = 0;
406 
407 	LIST_INSERT_HEAD(&encaptab, ep, chain);
408 #ifdef USE_RADIX
409 	if (!ep->func && rnh) {
410 		if (!rnh->rnh_addaddr((void *)ep->addrpack,
411 		    (void *)ep->maskpack, rnh, ep->nodes)) {
412 			error = EEXIST;
413 			goto fail;
414 		}
415 	}
416 #endif
417 	return error;
418 
419  fail:
420 	LIST_REMOVE(ep, chain);
421 	return error;
422 }
423 
424 static int
425 encap_remove(struct encaptab *ep)
426 {
427 #ifdef USE_RADIX
428 	struct radix_node_head *rnh = encap_rnh(ep->af);
429 #endif
430 	int error = 0;
431 
432 	LIST_REMOVE(ep, chain);
433 #ifdef USE_RADIX
434 	if (!ep->func && rnh) {
435 		if (!rnh->rnh_deladdr((void *)ep->addrpack,
436 		    (void *)ep->maskpack, rnh))
437 			error = ESRCH;
438 	}
439 #endif
440 	return error;
441 }
442 
443 static int
444 encap_afcheck(int af, const struct sockaddr *sp, const struct sockaddr *dp)
445 {
446 	if (sp && dp) {
447 		if (sp->sa_len != dp->sa_len)
448 			return EINVAL;
449 		if (af != sp->sa_family || af != dp->sa_family)
450 			return EINVAL;
451 	} else if (!sp && !dp)
452 		;
453 	else
454 		return EINVAL;
455 
456 	switch (af) {
457 	case AF_INET:
458 		if (sp && sp->sa_len != sizeof(struct sockaddr_in))
459 			return EINVAL;
460 		if (dp && dp->sa_len != sizeof(struct sockaddr_in))
461 			return EINVAL;
462 		break;
463 #ifdef INET6
464 	case AF_INET6:
465 		if (sp && sp->sa_len != sizeof(struct sockaddr_in6))
466 			return EINVAL;
467 		if (dp && dp->sa_len != sizeof(struct sockaddr_in6))
468 			return EINVAL;
469 		break;
470 #endif
471 	default:
472 		return EAFNOSUPPORT;
473 	}
474 
475 	return 0;
476 }
477 
478 /*
479  * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
480  * length of mask (sm and dm) is assumed to be same as sp/dp.
481  * Return value will be necessary as input (cookie) for encap_detach().
482  */
483 const struct encaptab *
484 encap_attach(int af, int proto,
485     const struct sockaddr *sp, const struct sockaddr *sm,
486     const struct sockaddr *dp, const struct sockaddr *dm,
487     const struct protosw *psw, void *arg)
488 {
489 	struct encaptab *ep;
490 	int error;
491 	int s;
492 	size_t l;
493 	struct ip_pack4 *pack4;
494 #ifdef INET6
495 	struct ip_pack6 *pack6;
496 #endif
497 
498 	s = splsoftnet();
499 	/* sanity check on args */
500 	error = encap_afcheck(af, sp, dp);
501 	if (error)
502 		goto fail;
503 
504 	/* check if anyone have already attached with exactly same config */
505 	LIST_FOREACH(ep, &encaptab, chain) {
506 		if (ep->af != af)
507 			continue;
508 		if (ep->proto != proto)
509 			continue;
510 		if (ep->func)
511 			continue;
512 #ifdef DIAGNOSTIC
513 		if (!ep->src || !ep->dst || !ep->srcmask || !ep->dstmask)
514 			panic("null pointers in encaptab");
515 #endif
516 		if (ep->src->sa_len != sp->sa_len ||
517 		    bcmp(ep->src, sp, sp->sa_len) != 0 ||
518 		    bcmp(ep->srcmask, sm, sp->sa_len) != 0)
519 			continue;
520 		if (ep->dst->sa_len != dp->sa_len ||
521 		    bcmp(ep->dst, dp, dp->sa_len) != 0 ||
522 		    bcmp(ep->dstmask, dm, dp->sa_len) != 0)
523 			continue;
524 
525 		error = EEXIST;
526 		goto fail;
527 	}
528 
529 	switch (af) {
530 	case AF_INET:
531 		l = sizeof(*pack4);
532 		break;
533 #ifdef INET6
534 	case AF_INET6:
535 		l = sizeof(*pack6);
536 		break;
537 #endif
538 	default:
539 		goto fail;
540 	}
541 
542 	/* M_NETADDR ok? */
543 	ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT|M_ZERO);
544 	if (ep == NULL) {
545 		error = ENOBUFS;
546 		goto fail;
547 	}
548 	ep->addrpack = malloc(l, M_NETADDR, M_NOWAIT|M_ZERO);
549 	if (ep->addrpack == NULL) {
550 		error = ENOBUFS;
551 		goto gc;
552 	}
553 	ep->maskpack = malloc(l, M_NETADDR, M_NOWAIT|M_ZERO);
554 	if (ep->maskpack == NULL) {
555 		error = ENOBUFS;
556 		goto gc;
557 	}
558 
559 	ep->af = af;
560 	ep->proto = proto;
561 	ep->addrpack->sa_len = l & 0xff;
562 	ep->maskpack->sa_len = l & 0xff;
563 	switch (af) {
564 	case AF_INET:
565 		pack4 = (struct ip_pack4 *)ep->addrpack;
566 		ep->src = (struct sockaddr *)&pack4->mine;
567 		ep->dst = (struct sockaddr *)&pack4->yours;
568 		pack4 = (struct ip_pack4 *)ep->maskpack;
569 		ep->srcmask = (struct sockaddr *)&pack4->mine;
570 		ep->dstmask = (struct sockaddr *)&pack4->yours;
571 		break;
572 #ifdef INET6
573 	case AF_INET6:
574 		pack6 = (struct ip_pack6 *)ep->addrpack;
575 		ep->src = (struct sockaddr *)&pack6->mine;
576 		ep->dst = (struct sockaddr *)&pack6->yours;
577 		pack6 = (struct ip_pack6 *)ep->maskpack;
578 		ep->srcmask = (struct sockaddr *)&pack6->mine;
579 		ep->dstmask = (struct sockaddr *)&pack6->yours;
580 		break;
581 #endif
582 	}
583 
584 	bcopy(sp, ep->src, sp->sa_len);
585 	bcopy(sm, ep->srcmask, sp->sa_len);
586 	bcopy(dp, ep->dst, dp->sa_len);
587 	bcopy(dm, ep->dstmask, dp->sa_len);
588 	ep->psw = psw;
589 	ep->arg = arg;
590 
591 	error = encap_add(ep);
592 	if (error)
593 		goto gc;
594 
595 	error = 0;
596 	splx(s);
597 	return ep;
598 
599 gc:
600 	if (ep->addrpack)
601 		free(ep->addrpack, M_NETADDR);
602 	if (ep->maskpack)
603 		free(ep->maskpack, M_NETADDR);
604 	if (ep)
605 		free(ep, M_NETADDR);
606 fail:
607 	splx(s);
608 	return NULL;
609 }
610 
611 const struct encaptab *
612 encap_attach_func(int af, int proto,
613     int (*func)(struct mbuf *, int, int, void *),
614     const struct protosw *psw, void *arg)
615 {
616 	struct encaptab *ep;
617 	int error;
618 	int s;
619 
620 	s = splsoftnet();
621 	/* sanity check on args */
622 	if (!func) {
623 		error = EINVAL;
624 		goto fail;
625 	}
626 
627 	error = encap_afcheck(af, NULL, NULL);
628 	if (error)
629 		goto fail;
630 
631 	ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT);	/*XXX*/
632 	if (ep == NULL) {
633 		error = ENOBUFS;
634 		goto fail;
635 	}
636 	bzero(ep, sizeof(*ep));
637 
638 	ep->af = af;
639 	ep->proto = proto;
640 	ep->func = func;
641 	ep->psw = psw;
642 	ep->arg = arg;
643 
644 	error = encap_add(ep);
645 	if (error)
646 		goto fail;
647 
648 	error = 0;
649 	splx(s);
650 	return ep;
651 
652 fail:
653 	splx(s);
654 	return NULL;
655 }
656 
657 /* XXX encap4_ctlinput() is necessary if we set DF=1 on outer IPv4 header */
658 
659 #ifdef INET6
660 void *
661 encap6_ctlinput(int cmd, const struct sockaddr *sa, void *d0)
662 {
663 	void *d = d0;
664 	struct ip6_hdr *ip6;
665 	struct mbuf *m;
666 	int off;
667 	struct ip6ctlparam *ip6cp = NULL;
668 	int nxt;
669 	struct encaptab *ep;
670 	const struct ip6protosw *psw;
671 
672 	if (sa->sa_family != AF_INET6 ||
673 	    sa->sa_len != sizeof(struct sockaddr_in6))
674 		return NULL;
675 
676 	if ((unsigned)cmd >= PRC_NCMDS)
677 		return NULL;
678 	if (cmd == PRC_HOSTDEAD)
679 		d = NULL;
680 	else if (cmd == PRC_MSGSIZE)
681 		; /* special code is present, see below */
682 	else if (inet6ctlerrmap[cmd] == 0)
683 		return NULL;
684 
685 	/* if the parameter is from icmp6, decode it. */
686 	if (d != NULL) {
687 		ip6cp = (struct ip6ctlparam *)d;
688 		m = ip6cp->ip6c_m;
689 		ip6 = ip6cp->ip6c_ip6;
690 		off = ip6cp->ip6c_off;
691 		nxt = ip6cp->ip6c_nxt;
692 
693 		if (ip6 && cmd == PRC_MSGSIZE) {
694 			int valid = 0;
695 			struct encaptab *match;
696 
697 			/*
698 		 	* Check to see if we have a valid encap configuration.
699 		 	*/
700 			match = encap6_lookup(m, off, nxt, OUTBOUND);
701 			if (match)
702 				valid++;
703 
704 			/*
705 		 	* Depending on the value of "valid" and routing table
706 		 	* size (mtudisc_{hi,lo}wat), we will:
707 		 	* - recalcurate the new MTU and create the
708 		 	*   corresponding routing entry, or
709 		 	* - ignore the MTU change notification.
710 		 	*/
711 			icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
712 		}
713 	} else {
714 		m = NULL;
715 		ip6 = NULL;
716 		nxt = -1;
717 	}
718 
719 	/* inform all listeners */
720 	LIST_FOREACH(ep, &encaptab, chain) {
721 		if (ep->af != AF_INET6)
722 			continue;
723 		if (ep->proto >= 0 && ep->proto != nxt)
724 			continue;
725 
726 		/* should optimize by looking at address pairs */
727 
728 		/* XXX need to pass ep->arg or ep itself to listeners */
729 		psw = (const struct ip6protosw *)ep->psw;
730 		if (psw && psw->pr_ctlinput)
731 			(*psw->pr_ctlinput)(cmd, sa, d);
732 	}
733 
734 	rip6_ctlinput(cmd, sa, d0);
735 	return NULL;
736 }
737 #endif
738 
739 int
740 encap_detach(const struct encaptab *cookie)
741 {
742 	const struct encaptab *ep = cookie;
743 	struct encaptab *p;
744 	int error;
745 
746 	LIST_FOREACH(p, &encaptab, chain) {
747 		if (p == ep) {
748 			error = encap_remove(p);
749 			if (error)
750 				return error;
751 			if (!ep->func) {
752 				free(p->addrpack, M_NETADDR);
753 				free(p->maskpack, M_NETADDR);
754 			}
755 			free(p, M_NETADDR);	/*XXX*/
756 			return 0;
757 		}
758 	}
759 
760 	return ENOENT;
761 }
762 
763 #ifdef USE_RADIX
764 static struct radix_node_head *
765 encap_rnh(int af)
766 {
767 
768 	switch (af) {
769 	case AF_INET:
770 		return encap_head[0];
771 #ifdef INET6
772 	case AF_INET6:
773 		return encap_head[1];
774 #endif
775 	default:
776 		return NULL;
777 	}
778 }
779 
780 static int
781 mask_matchlen(const struct sockaddr *sa)
782 {
783 	const char *p, *ep;
784 	int l;
785 
786 	p = (const char *)sa;
787 	ep = p + sa->sa_len;
788 	p += 2;	/* sa_len + sa_family */
789 
790 	l = 0;
791 	while (p < ep) {
792 		l += (*p ? 8 : 0);	/* estimate */
793 		p++;
794 	}
795 	return l;
796 }
797 #endif
798 
799 #ifndef USE_RADIX
800 static int
801 mask_match(const struct encaptab *ep,
802 	   const struct sockaddr *sp,
803 	   const struct sockaddr *dp)
804 {
805 	struct sockaddr_storage s;
806 	struct sockaddr_storage d;
807 	int i;
808 	const u_int8_t *p, *q;
809 	u_int8_t *r;
810 	int matchlen;
811 
812 #ifdef DIAGNOSTIC
813 	if (ep->func)
814 		panic("wrong encaptab passed to mask_match");
815 #endif
816 	if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d))
817 		return 0;
818 	if (sp->sa_family != ep->af || dp->sa_family != ep->af)
819 		return 0;
820 	if (sp->sa_len != ep->src->sa_len || dp->sa_len != ep->dst->sa_len)
821 		return 0;
822 
823 	matchlen = 0;
824 
825 	p = (const u_int8_t *)sp;
826 	q = (const u_int8_t *)ep->srcmask;
827 	r = (u_int8_t *)&s;
828 	for (i = 0 ; i < sp->sa_len; i++) {
829 		r[i] = p[i] & q[i];
830 		/* XXX estimate */
831 		matchlen += (q[i] ? 8 : 0);
832 	}
833 
834 	p = (const u_int8_t *)dp;
835 	q = (const u_int8_t *)ep->dstmask;
836 	r = (u_int8_t *)&d;
837 	for (i = 0 ; i < dp->sa_len; i++) {
838 		r[i] = p[i] & q[i];
839 		/* XXX rough estimate */
840 		matchlen += (q[i] ? 8 : 0);
841 	}
842 
843 	/* need to overwrite len/family portion as we don't compare them */
844 	s.ss_len = sp->sa_len;
845 	s.ss_family = sp->sa_family;
846 	d.ss_len = dp->sa_len;
847 	d.ss_family = dp->sa_family;
848 
849 	if (bcmp(&s, ep->src, ep->src->sa_len) == 0 &&
850 	    bcmp(&d, ep->dst, ep->dst->sa_len) == 0) {
851 		return matchlen;
852 	} else
853 		return 0;
854 }
855 #endif
856 
857 static void
858 encap_fillarg(struct mbuf *m, const struct encaptab *ep)
859 {
860 	struct m_tag *mtag;
861 
862 	mtag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), M_NOWAIT);
863 	if (mtag) {
864 		*(void **)(mtag + 1) = ep->arg;
865 		m_tag_prepend(m, mtag);
866 	}
867 }
868 
869 void *
870 encap_getarg(struct mbuf *m)
871 {
872 	void *p;
873 	struct m_tag *mtag;
874 
875 	p = NULL;
876 	mtag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
877 	if (mtag != NULL) {
878 		p = *(void **)(mtag + 1);
879 		m_tag_delete(m, mtag);
880 	}
881 	return p;
882 }
883