xref: /freebsd/sys/netipsec/ipsec_input.c (revision 2ed3236082a4473c1da8f72c1ebc071a7b54321f)
1 /*	$OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $	*/
2 /*-
3  * The authors of this code are John Ioannidis (ji@tla.org),
4  * Angelos D. Keromytis (kermit@csd.uch.gr) and
5  * Niels Provos (provos@physnet.uni-hamburg.de).
6  *
7  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
8  * in November 1995.
9  *
10  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
11  * by Angelos D. Keromytis.
12  *
13  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
14  * and Niels Provos.
15  *
16  * Additional features in 1999 by Angelos D. Keromytis.
17  *
18  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
19  * Angelos D. Keromytis and Niels Provos.
20  * Copyright (c) 2001, Angelos D. Keromytis.
21  * Copyright (c) 2016 Andrey V. Elsukov <ae@FreeBSD.org>
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 <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45 
46 #include "opt_inet.h"
47 #include "opt_inet6.h"
48 #include "opt_ipsec.h"
49 
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/malloc.h>
53 #include <sys/mbuf.h>
54 #include <sys/domain.h>
55 #include <sys/protosw.h>
56 #include <sys/socket.h>
57 #include <sys/errno.h>
58 #include <sys/hhook.h>
59 #include <sys/syslog.h>
60 
61 #include <net/if.h>
62 #include <net/if_var.h>
63 #include <net/if_enc.h>
64 #include <net/netisr.h>
65 #include <net/vnet.h>
66 
67 #include <netinet/in.h>
68 #include <netinet/in_systm.h>
69 #include <netinet/ip.h>
70 #include <netinet/ip_var.h>
71 #include <netinet/in_var.h>
72 
73 #include <netinet/ip6.h>
74 #ifdef INET6
75 #include <netinet6/ip6_var.h>
76 #endif
77 #include <netinet/in_pcb.h>
78 #ifdef INET6
79 #include <netinet/icmp6.h>
80 #endif
81 
82 #include <netipsec/ipsec.h>
83 #ifdef INET6
84 #include <netipsec/ipsec6.h>
85 #endif
86 #include <netipsec/ah_var.h>
87 #include <netipsec/esp.h>
88 #include <netipsec/esp_var.h>
89 #include <netipsec/ipcomp_var.h>
90 
91 #include <netipsec/key.h>
92 #include <netipsec/keydb.h>
93 #include <netipsec/key_debug.h>
94 
95 #include <netipsec/xform.h>
96 #include <netinet6/ip6protosw.h>
97 
98 #include <machine/in_cksum.h>
99 #include <machine/stdarg.h>
100 
101 #define	IPSEC_ISTAT(proto, name)	do {	\
102 	if ((proto) == IPPROTO_ESP)		\
103 		ESPSTAT_INC(esps_##name);	\
104 	else if ((proto) == IPPROTO_AH)		\
105 		AHSTAT_INC(ahs_##name);		\
106 	else					\
107 		IPCOMPSTAT_INC(ipcomps_##name);	\
108 } while (0)
109 
110 /*
111  * ipsec_common_input gets called when an IPsec-protected packet
112  * is received by IPv4 or IPv6.  Its job is to find the right SA
113  * and call the appropriate transform.  The transform callback
114  * takes care of further processing (like ingress filtering).
115  */
116 static int
117 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
118 {
119 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
120 	union sockaddr_union dst_address;
121 	struct secasvar *sav;
122 	uint32_t spi;
123 	int error;
124 
125 	IPSEC_ISTAT(sproto, input);
126 
127 	IPSEC_ASSERT(m != NULL, ("null packet"));
128 
129 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
130 		sproto == IPPROTO_IPCOMP,
131 		("unexpected security protocol %u", sproto));
132 
133 	if ((sproto == IPPROTO_ESP && !V_esp_enable) ||
134 	    (sproto == IPPROTO_AH && !V_ah_enable) ||
135 	    (sproto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
136 		m_freem(m);
137 		IPSEC_ISTAT(sproto, pdrops);
138 		return EOPNOTSUPP;
139 	}
140 
141 	if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
142 		m_freem(m);
143 		IPSEC_ISTAT(sproto, hdrops);
144 		DPRINTF(("%s: packet too small\n", __func__));
145 		return EINVAL;
146 	}
147 
148 	/* Retrieve the SPI from the relevant IPsec header */
149 	if (sproto == IPPROTO_ESP)
150 		m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
151 	else if (sproto == IPPROTO_AH)
152 		m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
153 		    (caddr_t) &spi);
154 	else if (sproto == IPPROTO_IPCOMP) {
155 		u_int16_t cpi;
156 		m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
157 		    (caddr_t) &cpi);
158 		spi = ntohl(htons(cpi));
159 	}
160 
161 	/*
162 	 * Find the SA and (indirectly) call the appropriate
163 	 * kernel crypto routine. The resulting mbuf chain is a valid
164 	 * IP packet ready to go through input processing.
165 	 */
166 	bzero(&dst_address, sizeof (dst_address));
167 	dst_address.sa.sa_family = af;
168 	switch (af) {
169 #ifdef INET
170 	case AF_INET:
171 		dst_address.sin.sin_len = sizeof(struct sockaddr_in);
172 		m_copydata(m, offsetof(struct ip, ip_dst),
173 		    sizeof(struct in_addr),
174 		    (caddr_t) &dst_address.sin.sin_addr);
175 		break;
176 #endif /* INET */
177 #ifdef INET6
178 	case AF_INET6:
179 		dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
180 		m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
181 		    sizeof(struct in6_addr),
182 		    (caddr_t) &dst_address.sin6.sin6_addr);
183 		/* We keep addresses in SADB without embedded scope id */
184 		if (IN6_IS_SCOPE_LINKLOCAL(&dst_address.sin6.sin6_addr)) {
185 			/* XXX: sa6_recoverscope() */
186 			dst_address.sin6.sin6_scope_id =
187 			    ntohs(dst_address.sin6.sin6_addr.s6_addr16[1]);
188 			dst_address.sin6.sin6_addr.s6_addr16[1] = 0;
189 		}
190 		break;
191 #endif /* INET6 */
192 	default:
193 		DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
194 		m_freem(m);
195 		IPSEC_ISTAT(sproto, nopf);
196 		return EPFNOSUPPORT;
197 	}
198 
199 	/* NB: only pass dst since key_allocsa follows RFC2401 */
200 	sav = key_allocsa(&dst_address, sproto, spi);
201 	if (sav == NULL) {
202 		DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
203 		    __func__, ipsec_address(&dst_address, buf, sizeof(buf)),
204 		    (u_long) ntohl(spi), sproto));
205 		IPSEC_ISTAT(sproto, notdb);
206 		m_freem(m);
207 		return ENOENT;
208 	}
209 
210 	if (sav->tdb_xform == NULL) {
211 		DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
212 		    __func__, ipsec_address(&dst_address, buf, sizeof(buf)),
213 		    (u_long) ntohl(spi), sproto));
214 		IPSEC_ISTAT(sproto, noxform);
215 		key_freesav(&sav);
216 		m_freem(m);
217 		return ENXIO;
218 	}
219 
220 	/*
221 	 * Call appropriate transform and return -- callback takes care of
222 	 * everything else.
223 	 */
224 	error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
225 	return (error);
226 }
227 
228 #ifdef INET
229 extern struct protosw inetsw[];
230 
231 /*
232  * IPSEC_INPUT() method implementation for IPv4.
233  *  0 - Permitted by inbound security policy for further processing.
234  *  EACCES - Forbidden by inbound security policy.
235  *  EINPROGRESS - consumed by IPsec.
236  */
237 int
238 ipsec4_input(struct mbuf *m, int offset, int proto)
239 {
240 
241 	switch (proto) {
242 	case IPPROTO_AH:
243 	case IPPROTO_ESP:
244 	case IPPROTO_IPCOMP:
245 		/* Do inbound IPsec processing for AH/ESP/IPCOMP */
246 		ipsec_common_input(m, offset,
247 		    offsetof(struct ip, ip_p), AF_INET, proto);
248 		return (EINPROGRESS); /* mbuf consumed by IPsec */
249 	default:
250 		/*
251 		 * Protocols with further headers get their IPsec treatment
252 		 * within the protocol specific processing.
253 		 */
254 		if ((inetsw[ip_protox[proto]].pr_flags & PR_LASTHDR) == 0)
255 			return (0);
256 		/* FALLTHROUGH */
257 	};
258 	/*
259 	 * Enforce IPsec policy checking if we are seeing last header.
260 	 */
261 	if (ipsec4_in_reject(m, NULL) != 0) {
262 		/* Forbidden by inbound security policy */
263 		m_freem(m);
264 		return (EACCES);
265 	}
266 	return (0);
267 }
268 
269 /*
270  * IPsec input callback for INET protocols.
271  * This routine is called as the transform callback.
272  * Takes care of filtering and other sanity checks on
273  * the processed packet.
274  */
275 int
276 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip,
277     int protoff)
278 {
279 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
280 	struct epoch_tracker et;
281 	struct ipsec_ctx_data ctx;
282 	struct xform_history *xh;
283 	struct secasindex *saidx;
284 	struct m_tag *mtag;
285 	struct ip *ip;
286 	int error, prot, af, sproto, isr_prot;
287 
288 	IPSEC_ASSERT(sav != NULL, ("null SA"));
289 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
290 	saidx = &sav->sah->saidx;
291 	af = saidx->dst.sa.sa_family;
292 	IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
293 	sproto = saidx->proto;
294 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
295 		sproto == IPPROTO_IPCOMP,
296 		("unexpected security protocol %u", sproto));
297 
298 	if (skip != 0) {
299 		/*
300 		 * Fix IPv4 header
301 		 */
302 		if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
303 			DPRINTF(("%s: processing failed for SA %s/%08lx\n",
304 			    __func__, ipsec_address(&sav->sah->saidx.dst,
305 			    buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
306 			IPSEC_ISTAT(sproto, hdrops);
307 			error = ENOBUFS;
308 			goto bad;
309 		}
310 
311 		ip = mtod(m, struct ip *);
312 		ip->ip_len = htons(m->m_pkthdr.len);
313 		ip->ip_sum = 0;
314 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
315 	} else {
316 		ip = mtod(m, struct ip *);
317 	}
318 	prot = ip->ip_p;
319 	/*
320 	 * Check that we have NAT-T enabled and apply transport mode
321 	 * decapsulation NAT procedure (RFC3948).
322 	 * Do this before invoking into the PFIL.
323 	 */
324 	if (sav->natt != NULL &&
325 	    (prot == IPPROTO_UDP || prot == IPPROTO_TCP))
326 		udp_ipsec_adjust_cksum(m, sav, prot, skip);
327 
328 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, AF_INET, IPSEC_ENC_BEFORE);
329 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
330 		goto bad;
331 	ip = mtod(m, struct ip *);	/* update pointer */
332 
333 	/* IP-in-IP encapsulation */
334 	if (prot == IPPROTO_IPIP &&
335 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
336 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
337 			IPSEC_ISTAT(sproto, hdrops);
338 			error = EINVAL;
339 			goto bad;
340 		}
341 		/* enc0: strip outer IPv4 header */
342 		m_striphdr(m, 0, ip->ip_hl << 2);
343 	}
344 #ifdef INET6
345 	/* IPv6-in-IP encapsulation. */
346 	else if (prot == IPPROTO_IPV6 &&
347 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
348 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
349 			IPSEC_ISTAT(sproto, hdrops);
350 			error = EINVAL;
351 			goto bad;
352 		}
353 		/* enc0: strip IPv4 header, keep IPv6 header only */
354 		m_striphdr(m, 0, ip->ip_hl << 2);
355 	}
356 #endif /* INET6 */
357 	else if (prot != IPPROTO_IPV6 && saidx->mode == IPSEC_MODE_ANY) {
358 		/*
359 		 * When mode is wildcard, inner protocol is IPv6 and
360 		 * we have no INET6 support - drop this packet a bit later.
361 		 * In other cases we assume transport mode. Set prot to
362 		 * correctly choose netisr.
363 		 */
364 		prot = IPPROTO_IPIP;
365 	}
366 
367 	/*
368 	 * Record what we've done to the packet (under what SA it was
369 	 * processed).
370 	 */
371 	if (sproto != IPPROTO_IPCOMP) {
372 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
373 		    sizeof(struct xform_history), M_NOWAIT);
374 		if (mtag == NULL) {
375 			DPRINTF(("%s: failed to get tag\n", __func__));
376 			IPSEC_ISTAT(sproto, hdrops);
377 			error = ENOMEM;
378 			goto bad;
379 		}
380 
381 		xh = (struct xform_history *)(mtag + 1);
382 		bcopy(&saidx->dst, &xh->dst, saidx->dst.sa.sa_len);
383 		xh->spi = sav->spi;
384 		xh->proto = sproto;
385 		xh->mode = saidx->mode;
386 		m_tag_prepend(m, mtag);
387 	}
388 
389 	key_sa_recordxfer(sav, m);		/* record data transfer */
390 
391 	/*
392 	 * In transport mode requeue decrypted mbuf back to IPv4 protocol
393 	 * handler. This is necessary to correctly expose rcvif.
394 	 */
395 	if (saidx->mode == IPSEC_MODE_TRANSPORT)
396 		prot = IPPROTO_IPIP;
397 	/*
398 	 * Re-dispatch via software interrupt.
399 	 */
400 	switch (prot) {
401 	case IPPROTO_IPIP:
402 		isr_prot = NETISR_IP;
403 		af = AF_INET;
404 		break;
405 #ifdef INET6
406 	case IPPROTO_IPV6:
407 		isr_prot = NETISR_IPV6;
408 		af = AF_INET6;
409 		break;
410 #endif
411 	default:
412 		DPRINTF(("%s: cannot handle inner ip proto %d\n",
413 			    __func__, prot));
414 		IPSEC_ISTAT(sproto, nopf);
415 		error = EPFNOSUPPORT;
416 		goto bad;
417 	}
418 
419 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_AFTER);
420 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
421 		goto bad;
422 
423 	/* Handle virtual tunneling interfaces */
424 	if (saidx->mode == IPSEC_MODE_TUNNEL)
425 		error = ipsec_if_input(m, sav, af);
426 	if (error == 0) {
427 		NET_EPOCH_ENTER(et);
428 		error = netisr_queue_src(isr_prot, (uintptr_t)sav->spi, m);
429 		NET_EPOCH_EXIT(et);
430 		if (error) {
431 			IPSEC_ISTAT(sproto, qfull);
432 			DPRINTF(("%s: queue full; proto %u packet dropped\n",
433 			    __func__, sproto));
434 		}
435 	}
436 	key_freesav(&sav);
437 	return (error);
438 bad:
439 	key_freesav(&sav);
440 	if (m != NULL)
441 		m_freem(m);
442 	return (error);
443 }
444 #endif /* INET */
445 
446 #ifdef INET6
447 /*
448  * IPSEC_INPUT() method implementation for IPv6.
449  *  0 - Permitted by inbound security policy for further processing.
450  *  EACCES - Forbidden by inbound security policy.
451  *  EINPROGRESS - consumed by IPsec.
452  */
453 int
454 ipsec6_input(struct mbuf *m, int offset, int proto)
455 {
456 
457 	switch (proto) {
458 	case IPPROTO_AH:
459 	case IPPROTO_ESP:
460 	case IPPROTO_IPCOMP:
461 		/* Do inbound IPsec processing for AH/ESP/IPCOMP */
462 		ipsec_common_input(m, offset,
463 		    offsetof(struct ip6_hdr, ip6_nxt), AF_INET6, proto);
464 		return (EINPROGRESS); /* mbuf consumed by IPsec */
465 	default:
466 		/*
467 		 * Protocols with further headers get their IPsec treatment
468 		 * within the protocol specific processing.
469 		 */
470 		if ((inet6sw[ip6_protox[proto]].pr_flags & PR_LASTHDR) == 0)
471 			return (0);
472 		/* FALLTHROUGH */
473 	};
474 	/*
475 	 * Enforce IPsec policy checking if we are seeing last header.
476 	 */
477 	if (ipsec6_in_reject(m, NULL) != 0) {
478 		/* Forbidden by inbound security policy */
479 		m_freem(m);
480 		return (EACCES);
481 	}
482 	return (0);
483 }
484 
485 /*
486  * IPsec input callback, called by the transform callback. Takes care of
487  * filtering and other sanity checks on the processed packet.
488  */
489 int
490 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip,
491     int protoff)
492 {
493 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
494 	struct epoch_tracker et;
495 	struct ipsec_ctx_data ctx;
496 	struct xform_history *xh;
497 	struct secasindex *saidx;
498 	struct ip6_hdr *ip6;
499 	struct m_tag *mtag;
500 	int prot, af, sproto;
501 	int nxt, isr_prot;
502 	int error, nest;
503 	uint8_t nxt8;
504 
505 	IPSEC_ASSERT(sav != NULL, ("null SA"));
506 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
507 	saidx = &sav->sah->saidx;
508 	af = saidx->dst.sa.sa_family;
509 	IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
510 	sproto = saidx->proto;
511 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
512 		sproto == IPPROTO_IPCOMP,
513 		("unexpected security protocol %u", sproto));
514 
515 	/* Fix IPv6 header */
516 	if (m->m_len < sizeof(struct ip6_hdr) &&
517 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
518 		DPRINTF(("%s: processing failed for SA %s/%08lx\n",
519 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
520 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
521 
522 		IPSEC_ISTAT(sproto, hdrops);
523 		error = EACCES;
524 		goto bad;
525 	}
526 
527 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_BEFORE);
528 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
529 		goto bad;
530 
531 	ip6 = mtod(m, struct ip6_hdr *);
532 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
533 
534 	/* Save protocol */
535 	m_copydata(m, protoff, 1, &nxt8);
536 	prot = nxt8;
537 
538 	/* IPv6-in-IP encapsulation */
539 	if (prot == IPPROTO_IPV6 &&
540 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
541 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
542 			IPSEC_ISTAT(sproto, hdrops);
543 			error = EINVAL;
544 			goto bad;
545 		}
546 		/* ip6n will now contain the inner IPv6 header. */
547 		m_striphdr(m, 0, skip);
548 		skip = 0;
549 	}
550 #ifdef INET
551 	/* IP-in-IP encapsulation */
552 	else if (prot == IPPROTO_IPIP &&
553 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
554 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
555 			IPSEC_ISTAT(sproto, hdrops);
556 			error = EINVAL;
557 			goto bad;
558 		}
559 		/* ipn will now contain the inner IPv4 header */
560 		m_striphdr(m, 0, skip);
561 		skip = 0;
562 	}
563 #endif /* INET */
564 	else {
565 		prot = IPPROTO_IPV6; /* for correct BPF processing */
566 	}
567 
568 	/*
569 	 * Record what we've done to the packet (under what SA it was
570 	 * processed).
571 	 */
572 	if (sproto != IPPROTO_IPCOMP) {
573 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
574 		    sizeof(struct xform_history), M_NOWAIT);
575 		if (mtag == NULL) {
576 			DPRINTF(("%s: failed to get tag\n", __func__));
577 			IPSEC_ISTAT(sproto, hdrops);
578 			error = ENOMEM;
579 			goto bad;
580 		}
581 
582 		xh = (struct xform_history *)(mtag + 1);
583 		bcopy(&saidx->dst, &xh->dst, saidx->dst.sa.sa_len);
584 		xh->spi = sav->spi;
585 		xh->proto = sproto;
586 		xh->mode = saidx->mode;
587 		m_tag_prepend(m, mtag);
588 	}
589 
590 	key_sa_recordxfer(sav, m);
591 
592 #ifdef INET
593 	if (prot == IPPROTO_IPIP)
594 		af = AF_INET;
595 	else
596 #endif
597 		af = AF_INET6;
598 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_AFTER);
599 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
600 		goto bad;
601 	if (skip == 0) {
602 		/*
603 		 * We stripped outer IPv6 header.
604 		 * Now we should requeue decrypted packet via netisr.
605 		 */
606 		switch (prot) {
607 #ifdef INET
608 		case IPPROTO_IPIP:
609 			isr_prot = NETISR_IP;
610 			break;
611 #endif
612 		case IPPROTO_IPV6:
613 			isr_prot = NETISR_IPV6;
614 			break;
615 		default:
616 			DPRINTF(("%s: cannot handle inner ip proto %d\n",
617 			    __func__, prot));
618 			IPSEC_ISTAT(sproto, nopf);
619 			error = EPFNOSUPPORT;
620 			goto bad;
621 		}
622 		/* Handle virtual tunneling interfaces */
623 		if (saidx->mode == IPSEC_MODE_TUNNEL)
624 			error = ipsec_if_input(m, sav, af);
625 		if (error == 0) {
626 			NET_EPOCH_ENTER(et);
627 			error = netisr_queue_src(isr_prot,
628 			    (uintptr_t)sav->spi, m);
629 			NET_EPOCH_EXIT(et);
630 			if (error) {
631 				IPSEC_ISTAT(sproto, qfull);
632 				DPRINTF(("%s: queue full; proto %u packet"
633 				    " dropped\n", __func__, sproto));
634 			}
635 		}
636 		key_freesav(&sav);
637 		return (error);
638 	}
639 	/*
640 	 * See the end of ip6_input for this logic.
641 	 * IPPROTO_IPV[46] case will be processed just like other ones
642 	 */
643 	nest = 0;
644 	nxt = nxt8;
645 	NET_EPOCH_ENTER(et);
646 	while (nxt != IPPROTO_DONE) {
647 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
648 			IP6STAT_INC(ip6s_toomanyhdr);
649 			error = EINVAL;
650 			goto bad_epoch;
651 		}
652 
653 		/*
654 		 * Protection against faulty packet - there should be
655 		 * more sanity checks in header chain processing.
656 		 */
657 		if (m->m_pkthdr.len < skip) {
658 			IP6STAT_INC(ip6s_tooshort);
659 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
660 			error = EINVAL;
661 			goto bad_epoch;
662 		}
663 		/*
664 		 * Enforce IPsec policy checking if we are seeing last header.
665 		 * note that we do not visit this with protocols with pcb layer
666 		 * code - like udp/tcp/raw ip.
667 		 */
668 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
669 		    ipsec6_in_reject(m, NULL)) {
670 			error = EINVAL;
671 			goto bad_epoch;
672 		}
673 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
674 	}
675 	NET_EPOCH_EXIT(et);
676 	key_freesav(&sav);
677 	return (0);
678 bad_epoch:
679 	NET_EPOCH_EXIT(et);
680 bad:
681 	key_freesav(&sav);
682 	if (m)
683 		m_freem(m);
684 	return (error);
685 }
686 #endif /* INET6 */
687