xref: /freebsd/sys/netipsec/ipsec_input.c (revision 85999a0155e389415cc476110fd5614baf543a55)
1 /*	$FreeBSD$	*/
2 /*	$OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $	*/
3 /*-
4  * The authors of this code are John Ioannidis (ji@tla.org),
5  * Angelos D. Keromytis (kermit@csd.uch.gr) and
6  * Niels Provos (provos@physnet.uni-hamburg.de).
7  *
8  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
9  * in November 1995.
10  *
11  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
12  * by Angelos D. Keromytis.
13  *
14  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
15  * and Niels Provos.
16  *
17  * Additional features in 1999 by Angelos D. Keromytis.
18  *
19  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
20  * Angelos D. Keromytis and Niels Provos.
21  * Copyright (c) 2001, Angelos D. Keromytis.
22  *
23  * Permission to use, copy, and modify this software with or without fee
24  * is hereby granted, provided that this entire notice is included in
25  * all copies of any software which is or includes a copy or
26  * modification of this software.
27  * You may use this code under the GNU public license if you so wish. Please
28  * contribute changes back to the authors under this freer than GPL license
29  * so that we may further the use of strong encryption without limitations to
30  * all.
31  *
32  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
33  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
34  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
35  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
36  * PURPOSE.
37  */
38 
39 /*
40  * IPsec input processing.
41  */
42 
43 #include "opt_inet.h"
44 #include "opt_inet6.h"
45 #include "opt_ipsec.h"
46 #include "opt_enc.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/domain.h>
53 #include <sys/protosw.h>
54 #include <sys/socket.h>
55 #include <sys/errno.h>
56 #include <sys/syslog.h>
57 
58 #include <net/if.h>
59 #include <net/route.h>
60 #include <net/netisr.h>
61 
62 #include <netinet/in.h>
63 #include <netinet/in_systm.h>
64 #include <netinet/ip.h>
65 #include <netinet/ip_var.h>
66 #include <netinet/in_var.h>
67 
68 #include <netinet/ip6.h>
69 #ifdef INET6
70 #include <netinet6/ip6_var.h>
71 #endif
72 #include <netinet/in_pcb.h>
73 #ifdef INET6
74 #include <netinet/icmp6.h>
75 #endif
76 
77 #include <netipsec/ipsec.h>
78 #ifdef INET6
79 #include <netipsec/ipsec6.h>
80 #endif
81 #include <netipsec/ah_var.h>
82 #include <netipsec/esp.h>
83 #include <netipsec/esp_var.h>
84 #include <netipsec/ipcomp_var.h>
85 
86 #include <netipsec/key.h>
87 #include <netipsec/keydb.h>
88 
89 #include <netipsec/xform.h>
90 #include <netinet6/ip6protosw.h>
91 
92 #include <machine/in_cksum.h>
93 #include <machine/stdarg.h>
94 
95 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
96 			    (p) == IPPROTO_AH ? (y)++ : (z)++)
97 
98 static void ipsec4_common_ctlinput(int, struct sockaddr *, void *, int);
99 
100 /*
101  * ipsec_common_input gets called when an IPsec-protected packet
102  * is received by IPv4 or IPv6.  It's job is to find the right SA
103  # and call the appropriate transform.  The transform callback
104  * takes care of further processing (like ingress filtering).
105  */
106 static int
107 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
108 {
109 	union sockaddr_union dst_address;
110 	struct secasvar *sav;
111 	u_int32_t spi;
112 	int error;
113 
114 	IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input,
115 		ipcompstat.ipcomps_input);
116 
117 	IPSEC_ASSERT(m != NULL, ("null packet"));
118 
119 	if ((sproto == IPPROTO_ESP && !esp_enable) ||
120 	    (sproto == IPPROTO_AH && !ah_enable) ||
121 	    (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) {
122 		m_freem(m);
123 		IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops,
124 		    ipcompstat.ipcomps_pdrops);
125 		return EOPNOTSUPP;
126 	}
127 
128 	if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
129 		m_freem(m);
130 		IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
131 		    ipcompstat.ipcomps_hdrops);
132 		DPRINTF(("%s: packet too small\n", __func__));
133 		return EINVAL;
134 	}
135 
136 	/* Retrieve the SPI from the relevant IPsec header */
137 	if (sproto == IPPROTO_ESP)
138 		m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
139 	else if (sproto == IPPROTO_AH)
140 		m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
141 		    (caddr_t) &spi);
142 	else if (sproto == IPPROTO_IPCOMP) {
143 		u_int16_t cpi;
144 		m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
145 		    (caddr_t) &cpi);
146 		spi = ntohl(htons(cpi));
147 	}
148 
149 	/*
150 	 * Find the SA and (indirectly) call the appropriate
151 	 * kernel crypto routine. The resulting mbuf chain is a valid
152 	 * IP packet ready to go through input processing.
153 	 */
154 	bzero(&dst_address, sizeof (dst_address));
155 	dst_address.sa.sa_family = af;
156 	switch (af) {
157 #ifdef INET
158 	case AF_INET:
159 		dst_address.sin.sin_len = sizeof(struct sockaddr_in);
160 		m_copydata(m, offsetof(struct ip, ip_dst),
161 		    sizeof(struct in_addr),
162 		    (caddr_t) &dst_address.sin.sin_addr);
163 		break;
164 #endif /* INET */
165 #ifdef INET6
166 	case AF_INET6:
167 		dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
168 		m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
169 		    sizeof(struct in6_addr),
170 		    (caddr_t) &dst_address.sin6.sin6_addr);
171 		break;
172 #endif /* INET6 */
173 	default:
174 		DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
175 		m_freem(m);
176 		IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf,
177 		    ipcompstat.ipcomps_nopf);
178 		return EPFNOSUPPORT;
179 	}
180 
181 	/* NB: only pass dst since key_allocsa follows RFC2401 */
182 	sav = KEY_ALLOCSA(&dst_address, sproto, spi);
183 	if (sav == NULL) {
184 		DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
185 			  __func__, ipsec_address(&dst_address),
186 			  (u_long) ntohl(spi), sproto));
187 		IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb,
188 		    ipcompstat.ipcomps_notdb);
189 		m_freem(m);
190 		return ENOENT;
191 	}
192 
193 	if (sav->tdb_xform == NULL) {
194 		DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
195 			 __func__, ipsec_address(&dst_address),
196 			 (u_long) ntohl(spi), sproto));
197 		IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform,
198 		    ipcompstat.ipcomps_noxform);
199 		KEY_FREESAV(&sav);
200 		m_freem(m);
201 		return ENXIO;
202 	}
203 
204 	/*
205 	 * Call appropriate transform and return -- callback takes care of
206 	 * everything else.
207 	 */
208 	error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
209 	KEY_FREESAV(&sav);
210 	return error;
211 }
212 
213 #ifdef INET
214 /*
215  * Common input handler for IPv4 AH, ESP, and IPCOMP.
216  */
217 int
218 ipsec4_common_input(struct mbuf *m, ...)
219 {
220 	va_list ap;
221 	int off, nxt;
222 
223 	va_start(ap, m);
224 	off = va_arg(ap, int);
225 	nxt = va_arg(ap, int);
226 	va_end(ap);
227 
228 	return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
229 				  AF_INET, nxt);
230 }
231 
232 void
233 ah4_input(struct mbuf *m, int off)
234 {
235 	ipsec4_common_input(m, off, IPPROTO_AH);
236 }
237 void
238 ah4_ctlinput(int cmd, struct sockaddr *sa, void *v)
239 {
240 	if (sa->sa_family == AF_INET &&
241 	    sa->sa_len == sizeof(struct sockaddr_in))
242 		ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_AH);
243 }
244 
245 void
246 esp4_input(struct mbuf *m, int off)
247 {
248 	ipsec4_common_input(m, off, IPPROTO_ESP);
249 }
250 void
251 esp4_ctlinput(int cmd, struct sockaddr *sa, void *v)
252 {
253 	if (sa->sa_family == AF_INET &&
254 	    sa->sa_len == sizeof(struct sockaddr_in))
255 		ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_ESP);
256 }
257 
258 void
259 ipcomp4_input(struct mbuf *m, int off)
260 {
261 	ipsec4_common_input(m, off, IPPROTO_IPCOMP);
262 }
263 
264 /*
265  * IPsec input callback for INET protocols.
266  * This routine is called as the transform callback.
267  * Takes care of filtering and other sanity checks on
268  * the processed packet.
269  */
270 int
271 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
272 			int skip, int protoff, struct m_tag *mt)
273 {
274 	int prot, af, sproto;
275 	struct ip *ip;
276 	struct m_tag *mtag;
277 	struct tdb_ident *tdbi;
278 	struct secasindex *saidx;
279 	int error;
280 #ifdef INET6
281 #ifdef notyet
282 	char ip6buf[INET6_ADDRSTRLEN];
283 #endif
284 #endif
285 
286 	IPSEC_SPLASSERT_SOFTNET(__func__);
287 
288 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
289 	IPSEC_ASSERT(sav != NULL, ("null SA"));
290 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
291 	saidx = &sav->sah->saidx;
292 	af = saidx->dst.sa.sa_family;
293 	IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
294 	sproto = saidx->proto;
295 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
296 		sproto == IPPROTO_IPCOMP,
297 		("unexpected security protocol %u", sproto));
298 
299 	/* Sanity check */
300 	if (m == NULL) {
301 		DPRINTF(("%s: null mbuf", __func__));
302 		IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
303 		    ipcompstat.ipcomps_badkcr);
304 		KEY_FREESAV(&sav);
305 		return EINVAL;
306 	}
307 
308 	if (skip != 0) {
309 		/* Fix IPv4 header */
310 		if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
311 			DPRINTF(("%s: processing failed for SA %s/%08lx\n",
312 			    __func__, ipsec_address(&sav->sah->saidx.dst),
313 			    (u_long) ntohl(sav->spi)));
314 			IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
315 			    ipcompstat.ipcomps_hdrops);
316 			error = ENOBUFS;
317 			goto bad;
318 		}
319 
320 		ip = mtod(m, struct ip *);
321 		ip->ip_len = htons(m->m_pkthdr.len);
322 		ip->ip_off = htons(ip->ip_off);
323 		ip->ip_sum = 0;
324 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
325 	} else {
326 		ip = mtod(m, struct ip *);
327 	}
328 	prot = ip->ip_p;
329 
330 #ifdef notyet
331 	/* IP-in-IP encapsulation */
332 	if (prot == IPPROTO_IPIP) {
333 		struct ip ipn;
334 
335 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
336 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
337 			    ahstat.ahs_hdrops,
338 			    ipcompstat.ipcomps_hdrops);
339 			error = EINVAL;
340 			goto bad;
341 		}
342 		/* ipn will now contain the inner IPv4 header */
343 		m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
344 		    (caddr_t) &ipn);
345 
346 		/* XXX PROXY address isn't recorded in SAH */
347 		/*
348 		 * Check that the inner source address is the same as
349 		 * the proxy address, if available.
350 		 */
351 		if ((saidx->proxy.sa.sa_family == AF_INET &&
352 		    saidx->proxy.sin.sin_addr.s_addr !=
353 		    INADDR_ANY &&
354 		    ipn.ip_src.s_addr !=
355 		    saidx->proxy.sin.sin_addr.s_addr) ||
356 		    (saidx->proxy.sa.sa_family != AF_INET &&
357 			saidx->proxy.sa.sa_family != 0)) {
358 
359 			DPRINTF(("%s: inner source address %s doesn't "
360 			    "correspond to expected proxy source %s, "
361 			    "SA %s/%08lx\n", __func__,
362 			    inet_ntoa4(ipn.ip_src),
363 			    ipsp_address(saidx->proxy),
364 			    ipsp_address(saidx->dst),
365 			    (u_long) ntohl(sav->spi)));
366 
367 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
368 			    ahstat.ahs_pdrops,
369 			    ipcompstat.ipcomps_pdrops);
370 			error = EACCES;
371 			goto bad;
372 		}
373 	}
374 #ifdef INET6
375 	/* IPv6-in-IP encapsulation. */
376 	if (prot == IPPROTO_IPV6) {
377 		struct ip6_hdr ip6n;
378 
379 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
380 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
381 			    ahstat.ahs_hdrops,
382 			    ipcompstat.ipcomps_hdrops);
383 			error = EINVAL;
384 			goto bad;
385 		}
386 		/* ip6n will now contain the inner IPv6 header. */
387 		m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
388 		    (caddr_t) &ip6n);
389 
390 		/*
391 		 * Check that the inner source address is the same as
392 		 * the proxy address, if available.
393 		 */
394 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
395 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
396 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
397 			&saidx->proxy.sin6.sin6_addr)) ||
398 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
399 			saidx->proxy.sa.sa_family != 0)) {
400 
401 			DPRINTF(("%s: inner source address %s doesn't "
402 			    "correspond to expected proxy source %s, "
403 			    "SA %s/%08lx\n", __func__,
404 			    ip6_sprintf(ip6buf, &ip6n.ip6_src),
405 			    ipsec_address(&saidx->proxy),
406 			    ipsec_address(&saidx->dst),
407 			    (u_long) ntohl(sav->spi)));
408 
409 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
410 			    ahstat.ahs_pdrops,
411 			    ipcompstat.ipcomps_pdrops);
412 			error = EACCES;
413 			goto bad;
414 		}
415 	}
416 #endif /* INET6 */
417 #endif /*XXX*/
418 
419 	/*
420 	 * Record what we've done to the packet (under what SA it was
421 	 * processed). If we've been passed an mtag, it means the packet
422 	 * was already processed by an ethernet/crypto combo card and
423 	 * thus has a tag attached with all the right information, but
424 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
425 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
426 	 */
427 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
428 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
429 		    sizeof(struct tdb_ident), M_NOWAIT);
430 		if (mtag == NULL) {
431 			DPRINTF(("%s: failed to get tag\n", __func__));
432 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
433 			    ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
434 			error = ENOMEM;
435 			goto bad;
436 		}
437 
438 		tdbi = (struct tdb_ident *)(mtag + 1);
439 		bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
440 		tdbi->proto = sproto;
441 		tdbi->spi = sav->spi;
442 
443 		m_tag_prepend(m, mtag);
444 	} else {
445 		mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
446 		/* XXX do we need to mark m_flags??? */
447 	}
448 
449 	key_sa_recordxfer(sav, m);		/* record data transfer */
450 
451 #ifdef DEV_ENC
452 	/*
453 	 * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
454 	 * packet later after it has been decapsulated.
455 	 */
456 	ipsec_bpf(m, sav, AF_INET);
457 
458 	if (prot != IPPROTO_IPIP)
459 		if ((error = ipsec_filter(&m, 1)) != 0)
460 			return (error);
461 #endif
462 
463 	/*
464 	 * Re-dispatch via software interrupt.
465 	 */
466 	if ((error = netisr_queue(NETISR_IP, m))) {
467 		IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
468 			    ipcompstat.ipcomps_qfull);
469 
470 		DPRINTF(("%s: queue full; proto %u packet dropped\n",
471 			__func__, sproto));
472 		return error;
473 	}
474 	return 0;
475 bad:
476 	m_freem(m);
477 	return error;
478 }
479 
480 void
481 ipsec4_common_ctlinput(int cmd, struct sockaddr *sa, void *v, int proto)
482 {
483 	/* XXX nothing just yet */
484 }
485 #endif /* INET */
486 
487 #ifdef INET6
488 /* IPv6 AH wrapper. */
489 int
490 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
491 {
492 	int l = 0;
493 	int protoff;
494 	struct ip6_ext ip6e;
495 
496 	if (*offp < sizeof(struct ip6_hdr)) {
497 		DPRINTF(("%s: bad offset %u\n", __func__, *offp));
498 		return IPPROTO_DONE;
499 	} else if (*offp == sizeof(struct ip6_hdr)) {
500 		protoff = offsetof(struct ip6_hdr, ip6_nxt);
501 	} else {
502 		/* Chase down the header chain... */
503 		protoff = sizeof(struct ip6_hdr);
504 
505 		do {
506 			protoff += l;
507 			m_copydata(*mp, protoff, sizeof(ip6e),
508 			    (caddr_t) &ip6e);
509 
510 			if (ip6e.ip6e_nxt == IPPROTO_AH)
511 				l = (ip6e.ip6e_len + 2) << 2;
512 			else
513 				l = (ip6e.ip6e_len + 1) << 3;
514 			IPSEC_ASSERT(l > 0, ("l went zero or negative"));
515 		} while (protoff + l < *offp);
516 
517 		/* Malformed packet check */
518 		if (protoff + l != *offp) {
519 			DPRINTF(("%s: bad packet header chain, protoff %u, "
520 				"l %u, off %u\n", __func__, protoff, l, *offp));
521 			IPSEC_ISTAT(proto, espstat.esps_hdrops,
522 				    ahstat.ahs_hdrops,
523 				    ipcompstat.ipcomps_hdrops);
524 			m_freem(*mp);
525 			*mp = NULL;
526 			return IPPROTO_DONE;
527 		}
528 		protoff += offsetof(struct ip6_ext, ip6e_nxt);
529 	}
530 	(void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
531 	return IPPROTO_DONE;
532 }
533 
534 /*
535  * IPsec input callback, called by the transform callback. Takes care of
536  * filtering and other sanity checks on the processed packet.
537  */
538 int
539 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
540     struct m_tag *mt)
541 {
542 	int prot, af, sproto;
543 	struct ip6_hdr *ip6;
544 	struct m_tag *mtag;
545 	struct tdb_ident *tdbi;
546 	struct secasindex *saidx;
547 	int nxt;
548 	u_int8_t nxt8;
549 	int error, nest;
550 #ifdef notyet
551 	char ip6buf[INET6_ADDRSTRLEN];
552 #endif
553 
554 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
555 	IPSEC_ASSERT(sav != NULL, ("null SA"));
556 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
557 	saidx = &sav->sah->saidx;
558 	af = saidx->dst.sa.sa_family;
559 	IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
560 	sproto = saidx->proto;
561 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
562 		sproto == IPPROTO_IPCOMP,
563 		("unexpected security protocol %u", sproto));
564 
565 	/* Sanity check */
566 	if (m == NULL) {
567 		DPRINTF(("%s: null mbuf", __func__));
568 		IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
569 		    ipcompstat.ipcomps_badkcr);
570 		error = EINVAL;
571 		goto bad;
572 	}
573 
574 	/* Fix IPv6 header */
575 	if (m->m_len < sizeof(struct ip6_hdr) &&
576 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
577 
578 		DPRINTF(("%s: processing failed for SA %s/%08lx\n",
579 		    __func__, ipsec_address(&sav->sah->saidx.dst),
580 		    (u_long) ntohl(sav->spi)));
581 
582 		IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
583 		    ipcompstat.ipcomps_hdrops);
584 		error = EACCES;
585 		goto bad;
586 	}
587 
588 	ip6 = mtod(m, struct ip6_hdr *);
589 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
590 
591 	/* Save protocol */
592 	m_copydata(m, protoff, 1, (unsigned char *) &prot);
593 
594 #ifdef notyet
595 #ifdef INET
596 	/* IP-in-IP encapsulation */
597 	if (prot == IPPROTO_IPIP) {
598 		struct ip ipn;
599 
600 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
601 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
602 			    ahstat.ahs_hdrops,
603 			    ipcompstat.ipcomps_hdrops);
604 			error = EINVAL;
605 			goto bad;
606 		}
607 		/* ipn will now contain the inner IPv4 header */
608 		m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
609 
610 		/*
611 		 * Check that the inner source address is the same as
612 		 * the proxy address, if available.
613 		 */
614 		if ((saidx->proxy.sa.sa_family == AF_INET &&
615 		    saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
616 		    ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
617 		    (saidx->proxy.sa.sa_family != AF_INET &&
618 			saidx->proxy.sa.sa_family != 0)) {
619 
620 			DPRINTF(("%s: inner source address %s doesn't "
621 			    "correspond to expected proxy source %s, "
622 			    "SA %s/%08lx\n", __func__,
623 			    inet_ntoa4(ipn.ip_src),
624 			    ipsec_address(&saidx->proxy),
625 			    ipsec_address(&saidx->dst),
626 			    (u_long) ntohl(sav->spi)));
627 
628 			IPSEC_ISTATsproto, (espstat.esps_pdrops,
629 			    ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
630 			error = EACCES;
631 			goto bad;
632 		}
633 	}
634 #endif /* INET */
635 
636 	/* IPv6-in-IP encapsulation */
637 	if (prot == IPPROTO_IPV6) {
638 		struct ip6_hdr ip6n;
639 
640 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
641 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
642 			    ahstat.ahs_hdrops,
643 			    ipcompstat.ipcomps_hdrops);
644 			error = EINVAL;
645 			goto bad;
646 		}
647 		/* ip6n will now contain the inner IPv6 header. */
648 		m_copydata(m, skip, sizeof(struct ip6_hdr),
649 		    (caddr_t) &ip6n);
650 
651 		/*
652 		 * Check that the inner source address is the same as
653 		 * the proxy address, if available.
654 		 */
655 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
656 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
657 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
658 			&saidx->proxy.sin6.sin6_addr)) ||
659 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
660 			saidx->proxy.sa.sa_family != 0)) {
661 
662 			DPRINTF(("%s: inner source address %s doesn't "
663 			    "correspond to expected proxy source %s, "
664 			    "SA %s/%08lx\n", __func__,
665 			    ip6_sprintf(ip6buf, &ip6n.ip6_src),
666 			    ipsec_address(&saidx->proxy),
667 			    ipsec_address(&saidx->dst),
668 			    (u_long) ntohl(sav->spi)));
669 
670 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
671 			    ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
672 			error = EACCES;
673 			goto bad;
674 		}
675 	}
676 #endif /*XXX*/
677 
678 	/*
679 	 * Record what we've done to the packet (under what SA it was
680 	 * processed). If we've been passed an mtag, it means the packet
681 	 * was already processed by an ethernet/crypto combo card and
682 	 * thus has a tag attached with all the right information, but
683 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
684 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
685 	 */
686 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
687 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
688 		    sizeof(struct tdb_ident), M_NOWAIT);
689 		if (mtag == NULL) {
690 			DPRINTF(("%s: failed to get tag\n", __func__));
691 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
692 			    ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
693 			error = ENOMEM;
694 			goto bad;
695 		}
696 
697 		tdbi = (struct tdb_ident *)(mtag + 1);
698 		bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
699 		tdbi->proto = sproto;
700 		tdbi->spi = sav->spi;
701 
702 		m_tag_prepend(m, mtag);
703 	} else {
704 		if (mt != NULL)
705 			mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
706 		/* XXX do we need to mark m_flags??? */
707 	}
708 
709 	key_sa_recordxfer(sav, m);
710 
711 	/* Retrieve new protocol */
712 	m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
713 
714 	/*
715 	 * See the end of ip6_input for this logic.
716 	 * IPPROTO_IPV[46] case will be processed just like other ones
717 	 */
718 	nest = 0;
719 	nxt = nxt8;
720 	while (nxt != IPPROTO_DONE) {
721 		if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
722 			ip6stat.ip6s_toomanyhdr++;
723 			error = EINVAL;
724 			goto bad;
725 		}
726 
727 		/*
728 		 * Protection against faulty packet - there should be
729 		 * more sanity checks in header chain processing.
730 		 */
731 		if (m->m_pkthdr.len < skip) {
732 			ip6stat.ip6s_tooshort++;
733 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
734 			error = EINVAL;
735 			goto bad;
736 		}
737 		/*
738 		 * Enforce IPsec policy checking if we are seeing last header.
739 		 * note that we do not visit this with protocols with pcb layer
740 		 * code - like udp/tcp/raw ip.
741 		 */
742 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
743 		    ipsec6_in_reject(m, NULL)) {
744 			error = EINVAL;
745 			goto bad;
746 		}
747 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
748 	}
749 	return 0;
750 bad:
751 	if (m)
752 		m_freem(m);
753 	return error;
754 }
755 
756 void
757 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
758 {
759 	if (sa->sa_family != AF_INET6 ||
760 	    sa->sa_len != sizeof(struct sockaddr_in6))
761 		return;
762 	if ((unsigned)cmd >= PRC_NCMDS)
763 		return;
764 
765 	/* if the parameter is from icmp6, decode it. */
766 	if (d !=  NULL) {
767 		struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
768 		struct mbuf *m = ip6cp->ip6c_m;
769 		int off = ip6cp->ip6c_off;
770 
771 		struct ip6ctlparam ip6cp1;
772 
773 		/*
774 		 * Notify the error to all possible sockets via pfctlinput2.
775 		 * Since the upper layer information (such as protocol type,
776 		 * source and destination ports) is embedded in the encrypted
777 		 * data and might have been cut, we can't directly call
778 		 * an upper layer ctlinput function. However, the pcbnotify
779 		 * function will consider source and destination addresses
780 		 * as well as the flow info value, and may be able to find
781 		 * some PCB that should be notified.
782 		 * Although pfctlinput2 will call esp6_ctlinput(), there is
783 		 * no possibility of an infinite loop of function calls,
784 		 * because we don't pass the inner IPv6 header.
785 		 */
786 		bzero(&ip6cp1, sizeof(ip6cp1));
787 		ip6cp1.ip6c_src = ip6cp->ip6c_src;
788 		pfctlinput2(cmd, sa, (void *)&ip6cp1);
789 
790 		/*
791 		 * Then go to special cases that need ESP header information.
792 		 * XXX: We assume that when ip6 is non NULL,
793 		 * M and OFF are valid.
794 		 */
795 
796 		if (cmd == PRC_MSGSIZE) {
797 			struct secasvar *sav;
798 			u_int32_t spi;
799 			int valid;
800 
801 			/* check header length before using m_copydata */
802 			if (m->m_pkthdr.len < off + sizeof (struct esp))
803 				return;
804 			m_copydata(m, off + offsetof(struct esp, esp_spi),
805 				sizeof(u_int32_t), (caddr_t) &spi);
806 			/*
807 			 * Check to see if we have a valid SA corresponding to
808 			 * the address in the ICMP message payload.
809 			 */
810 			sav = KEY_ALLOCSA((union sockaddr_union *)sa,
811 					IPPROTO_ESP, spi);
812 			valid = (sav != NULL);
813 			if (sav)
814 				KEY_FREESAV(&sav);
815 
816 			/* XXX Further validation? */
817 
818 			/*
819 			 * Depending on whether the SA is "valid" and
820 			 * routing table size (mtudisc_{hi,lo}wat), we will:
821 			 * - recalcurate the new MTU and create the
822 			 *   corresponding routing entry, or
823 			 * - ignore the MTU change notification.
824 			 */
825 			icmp6_mtudisc_update(ip6cp, valid);
826 		}
827 	} else {
828 		/* we normally notify any pcb here */
829 	}
830 }
831 #endif /* INET6 */
832