xref: /freebsd-13-stable/sys/netipsec/ipsec_input.c (revision 3bc80996974a61a4223eae4c1ccd47b6ee32a48a)
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 #include "opt_inet.h"
45 #include "opt_inet6.h"
46 #include "opt_ipsec.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/hhook.h>
57 #include <sys/syslog.h>
58 
59 #include <net/if.h>
60 #include <net/if_var.h>
61 #include <net/if_enc.h>
62 #include <net/netisr.h>
63 #include <net/vnet.h>
64 
65 #include <netinet/in.h>
66 #include <netinet/in_systm.h>
67 #include <netinet/ip.h>
68 #include <netinet/ip_var.h>
69 #include <netinet/in_var.h>
70 
71 #include <netinet/ip6.h>
72 #ifdef INET6
73 #include <netinet6/ip6_var.h>
74 #endif
75 #include <netinet/in_pcb.h>
76 #ifdef INET6
77 #include <netinet/icmp6.h>
78 #endif
79 
80 #include <netipsec/ipsec.h>
81 #ifdef INET6
82 #include <netipsec/ipsec6.h>
83 #endif
84 #include <netipsec/ah_var.h>
85 #include <netipsec/esp.h>
86 #include <netipsec/esp_var.h>
87 #include <netipsec/ipcomp_var.h>
88 
89 #include <netipsec/key.h>
90 #include <netipsec/keydb.h>
91 #include <netipsec/key_debug.h>
92 
93 #include <netipsec/xform.h>
94 #include <netinet6/ip6protosw.h>
95 
96 #include <machine/in_cksum.h>
97 #include <machine/stdarg.h>
98 
99 #define	IPSEC_ISTAT(proto, name)	do {	\
100 	if ((proto) == IPPROTO_ESP)		\
101 		ESPSTAT_INC(esps_##name);	\
102 	else if ((proto) == IPPROTO_AH)		\
103 		AHSTAT_INC(ahs_##name);		\
104 	else					\
105 		IPCOMPSTAT_INC(ipcomps_##name);	\
106 } while (0)
107 
108 /*
109  * ipsec_common_input gets called when an IPsec-protected packet
110  * is received by IPv4 or IPv6.  Its job is to find the right SA
111  * and call the appropriate transform.  The transform callback
112  * takes care of further processing (like ingress filtering).
113  */
114 static int
ipsec_common_input(struct mbuf * m,int skip,int protoff,int af,int sproto)115 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
116 {
117 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
118 	union sockaddr_union dst_address;
119 	struct secasvar *sav;
120 	uint32_t spi;
121 	int error;
122 
123 	IPSEC_ISTAT(sproto, input);
124 
125 	IPSEC_ASSERT(m != NULL, ("null packet"));
126 
127 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
128 		sproto == IPPROTO_IPCOMP,
129 		("unexpected security protocol %u", sproto));
130 
131 	if ((sproto == IPPROTO_ESP && !V_esp_enable) ||
132 	    (sproto == IPPROTO_AH && !V_ah_enable) ||
133 	    (sproto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
134 		m_freem(m);
135 		IPSEC_ISTAT(sproto, pdrops);
136 		return EOPNOTSUPP;
137 	}
138 
139 	if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
140 		m_freem(m);
141 		IPSEC_ISTAT(sproto, hdrops);
142 		DPRINTF(("%s: packet too small\n", __func__));
143 		return EINVAL;
144 	}
145 
146 	/* Retrieve the SPI from the relevant IPsec header */
147 	if (sproto == IPPROTO_ESP)
148 		m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
149 	else if (sproto == IPPROTO_AH)
150 		m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
151 		    (caddr_t) &spi);
152 	else if (sproto == IPPROTO_IPCOMP) {
153 		u_int16_t cpi;
154 		m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
155 		    (caddr_t) &cpi);
156 		spi = ntohl(htons(cpi));
157 	}
158 
159 	/*
160 	 * Find the SA and (indirectly) call the appropriate
161 	 * kernel crypto routine. The resulting mbuf chain is a valid
162 	 * IP packet ready to go through input processing.
163 	 */
164 	bzero(&dst_address, sizeof (dst_address));
165 	dst_address.sa.sa_family = af;
166 	switch (af) {
167 #ifdef INET
168 	case AF_INET:
169 		dst_address.sin.sin_len = sizeof(struct sockaddr_in);
170 		m_copydata(m, offsetof(struct ip, ip_dst),
171 		    sizeof(struct in_addr),
172 		    (caddr_t) &dst_address.sin.sin_addr);
173 		break;
174 #endif /* INET */
175 #ifdef INET6
176 	case AF_INET6:
177 		dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
178 		m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
179 		    sizeof(struct in6_addr),
180 		    (caddr_t) &dst_address.sin6.sin6_addr);
181 		/* We keep addresses in SADB without embedded scope id */
182 		if (IN6_IS_SCOPE_LINKLOCAL(&dst_address.sin6.sin6_addr)) {
183 			/* XXX: sa6_recoverscope() */
184 			dst_address.sin6.sin6_scope_id =
185 			    ntohs(dst_address.sin6.sin6_addr.s6_addr16[1]);
186 			dst_address.sin6.sin6_addr.s6_addr16[1] = 0;
187 		}
188 		break;
189 #endif /* INET6 */
190 	default:
191 		DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
192 		m_freem(m);
193 		IPSEC_ISTAT(sproto, nopf);
194 		return EPFNOSUPPORT;
195 	}
196 
197 	/* NB: only pass dst since key_allocsa follows RFC2401 */
198 	sav = key_allocsa(&dst_address, sproto, spi);
199 	if (sav == NULL) {
200 		DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
201 		    __func__, ipsec_address(&dst_address, buf, sizeof(buf)),
202 		    (u_long) ntohl(spi), sproto));
203 		IPSEC_ISTAT(sproto, notdb);
204 		m_freem(m);
205 		return ENOENT;
206 	}
207 
208 	if (sav->tdb_xform == NULL) {
209 		DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
210 		    __func__, ipsec_address(&dst_address, buf, sizeof(buf)),
211 		    (u_long) ntohl(spi), sproto));
212 		IPSEC_ISTAT(sproto, noxform);
213 		key_freesav(&sav);
214 		m_freem(m);
215 		return ENXIO;
216 	}
217 
218 	/*
219 	 * Call appropriate transform and return -- callback takes care of
220 	 * everything else.
221 	 */
222 	error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
223 	return (error);
224 }
225 
226 #ifdef INET
227 extern struct protosw inetsw[];
228 
229 /*
230  * IPSEC_INPUT() method implementation for IPv4.
231  *  0 - Permitted by inbound security policy for further processing.
232  *  EACCES - Forbidden by inbound security policy.
233  *  EINPROGRESS - consumed by IPsec.
234  */
235 int
ipsec4_input(struct mbuf * m,int offset,int proto)236 ipsec4_input(struct mbuf *m, int offset, int proto)
237 {
238 
239 	switch (proto) {
240 	case IPPROTO_AH:
241 	case IPPROTO_ESP:
242 	case IPPROTO_IPCOMP:
243 		/* Do inbound IPsec processing for AH/ESP/IPCOMP */
244 		ipsec_common_input(m, offset,
245 		    offsetof(struct ip, ip_p), AF_INET, proto);
246 		return (EINPROGRESS); /* mbuf consumed by IPsec */
247 	default:
248 		/*
249 		 * Protocols with further headers get their IPsec treatment
250 		 * within the protocol specific processing.
251 		 */
252 		if ((inetsw[ip_protox[proto]].pr_flags & PR_LASTHDR) == 0)
253 			return (0);
254 		/* FALLTHROUGH */
255 	};
256 	/*
257 	 * Enforce IPsec policy checking if we are seeing last header.
258 	 */
259 	if (ipsec4_in_reject(m, NULL) != 0) {
260 		/* Forbidden by inbound security policy */
261 		m_freem(m);
262 		return (EACCES);
263 	}
264 	return (0);
265 }
266 
267 /*
268  * IPsec input callback for INET protocols.
269  * This routine is called as the transform callback.
270  * Takes care of filtering and other sanity checks on
271  * the processed packet.
272  */
273 int
ipsec4_common_input_cb(struct mbuf * m,struct secasvar * sav,int skip,int protoff)274 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip,
275     int protoff)
276 {
277 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
278 	struct epoch_tracker et;
279 	struct ipsec_ctx_data ctx;
280 	struct xform_history *xh;
281 	struct secasindex *saidx;
282 	struct m_tag *mtag;
283 	struct ip *ip;
284 	int error, prot, af, sproto, isr_prot;
285 
286 	IPSEC_ASSERT(sav != NULL, ("null SA"));
287 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
288 	saidx = &sav->sah->saidx;
289 	af = saidx->dst.sa.sa_family;
290 	IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
291 	sproto = saidx->proto;
292 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
293 		sproto == IPPROTO_IPCOMP,
294 		("unexpected security protocol %u", sproto));
295 
296 	if (skip != 0) {
297 		/*
298 		 * Fix IPv4 header
299 		 */
300 		if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
301 			DPRINTF(("%s: processing failed for SA %s/%08lx\n",
302 			    __func__, ipsec_address(&sav->sah->saidx.dst,
303 			    buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
304 			IPSEC_ISTAT(sproto, hdrops);
305 			error = ENOBUFS;
306 			goto bad_noepoch;
307 		}
308 
309 		ip = mtod(m, struct ip *);
310 		ip->ip_len = htons(m->m_pkthdr.len);
311 		ip->ip_sum = 0;
312 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
313 	} else {
314 		ip = mtod(m, struct ip *);
315 	}
316 	prot = ip->ip_p;
317 	/*
318 	 * Check that we have NAT-T enabled and apply transport mode
319 	 * decapsulation NAT procedure (RFC3948).
320 	 * Do this before invoking into the PFIL.
321 	 */
322 	if (sav->natt != NULL &&
323 	    (prot == IPPROTO_UDP || prot == IPPROTO_TCP))
324 		udp_ipsec_adjust_cksum(m, sav, prot, skip);
325 
326 	/*
327 	 * Needed for ipsec_run_hooks and netisr_queue_src
328 	 */
329 	NET_EPOCH_ENTER(et);
330 
331 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, AF_INET, IPSEC_ENC_BEFORE);
332 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
333 		goto bad;
334 	ip = mtod(m, struct ip *);	/* update pointer */
335 
336 	/* IP-in-IP encapsulation */
337 	if (prot == IPPROTO_IPIP &&
338 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
339 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
340 			IPSEC_ISTAT(sproto, hdrops);
341 			error = EINVAL;
342 			goto bad;
343 		}
344 		/* enc0: strip outer IPv4 header */
345 		m_striphdr(m, 0, ip->ip_hl << 2);
346 	}
347 #ifdef INET6
348 	/* IPv6-in-IP encapsulation. */
349 	else if (prot == IPPROTO_IPV6 &&
350 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
351 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
352 			IPSEC_ISTAT(sproto, hdrops);
353 			error = EINVAL;
354 			goto bad;
355 		}
356 		/* enc0: strip IPv4 header, keep IPv6 header only */
357 		m_striphdr(m, 0, ip->ip_hl << 2);
358 	}
359 #endif /* INET6 */
360 	else if (prot != IPPROTO_IPV6 && saidx->mode == IPSEC_MODE_ANY) {
361 		/*
362 		 * When mode is wildcard, inner protocol is IPv6 and
363 		 * we have no INET6 support - drop this packet a bit later.
364 		 * In other cases we assume transport mode. Set prot to
365 		 * correctly choose netisr.
366 		 */
367 		prot = IPPROTO_IPIP;
368 	}
369 
370 	/*
371 	 * Record what we've done to the packet (under what SA it was
372 	 * processed).
373 	 */
374 	if (sproto != IPPROTO_IPCOMP) {
375 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
376 		    sizeof(struct xform_history), M_NOWAIT);
377 		if (mtag == NULL) {
378 			DPRINTF(("%s: failed to get tag\n", __func__));
379 			IPSEC_ISTAT(sproto, hdrops);
380 			error = ENOMEM;
381 			goto bad;
382 		}
383 
384 		xh = (struct xform_history *)(mtag + 1);
385 		bcopy(&saidx->dst, &xh->dst, saidx->dst.sa.sa_len);
386 		xh->spi = sav->spi;
387 		xh->proto = sproto;
388 		xh->mode = saidx->mode;
389 		m_tag_prepend(m, mtag);
390 	}
391 
392 	key_sa_recordxfer(sav, m);		/* record data transfer */
393 
394 	/*
395 	 * In transport mode requeue decrypted mbuf back to IPv4 protocol
396 	 * handler. This is necessary to correctly expose rcvif.
397 	 */
398 	if (saidx->mode == IPSEC_MODE_TRANSPORT)
399 		prot = IPPROTO_IPIP;
400 	/*
401 	 * Re-dispatch via software interrupt.
402 	 */
403 	switch (prot) {
404 	case IPPROTO_IPIP:
405 		isr_prot = NETISR_IP;
406 		af = AF_INET;
407 		break;
408 #ifdef INET6
409 	case IPPROTO_IPV6:
410 		isr_prot = NETISR_IPV6;
411 		af = AF_INET6;
412 		break;
413 #endif
414 	default:
415 		DPRINTF(("%s: cannot handle inner ip proto %d\n",
416 			    __func__, prot));
417 		IPSEC_ISTAT(sproto, nopf);
418 		error = EPFNOSUPPORT;
419 		goto bad;
420 	}
421 
422 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_AFTER);
423 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
424 		goto bad;
425 
426 	/* Handle virtual tunneling interfaces */
427 	if (saidx->mode == IPSEC_MODE_TUNNEL)
428 		error = ipsec_if_input(m, sav, af);
429 	if (error == 0) {
430 		error = netisr_queue_src(isr_prot, (uintptr_t)sav->spi, m);
431 		if (error) {
432 			IPSEC_ISTAT(sproto, qfull);
433 			DPRINTF(("%s: queue full; proto %u packet dropped\n",
434 			    __func__, sproto));
435 		}
436 	}
437 	NET_EPOCH_EXIT(et);
438 	key_freesav(&sav);
439 	return (error);
440 bad:
441 	NET_EPOCH_EXIT(et);
442 bad_noepoch:
443 	key_freesav(&sav);
444 	if (m != NULL)
445 		m_freem(m);
446 	return (error);
447 }
448 #endif /* INET */
449 
450 #ifdef INET6
451 /*
452  * IPSEC_INPUT() method implementation for IPv6.
453  *  0 - Permitted by inbound security policy for further processing.
454  *  EACCES - Forbidden by inbound security policy.
455  *  EINPROGRESS - consumed by IPsec.
456  */
457 int
ipsec6_input(struct mbuf * m,int offset,int proto)458 ipsec6_input(struct mbuf *m, int offset, int proto)
459 {
460 
461 	switch (proto) {
462 	case IPPROTO_AH:
463 	case IPPROTO_ESP:
464 	case IPPROTO_IPCOMP:
465 		/* Do inbound IPsec processing for AH/ESP/IPCOMP */
466 		ipsec_common_input(m, offset,
467 		    offsetof(struct ip6_hdr, ip6_nxt), AF_INET6, proto);
468 		return (EINPROGRESS); /* mbuf consumed by IPsec */
469 	default:
470 		/*
471 		 * Protocols with further headers get their IPsec treatment
472 		 * within the protocol specific processing.
473 		 */
474 		if ((inet6sw[ip6_protox[proto]].pr_flags & PR_LASTHDR) == 0)
475 			return (0);
476 		/* FALLTHROUGH */
477 	};
478 	/*
479 	 * Enforce IPsec policy checking if we are seeing last header.
480 	 */
481 	if (ipsec6_in_reject(m, NULL) != 0) {
482 		/* Forbidden by inbound security policy */
483 		m_freem(m);
484 		return (EACCES);
485 	}
486 	return (0);
487 }
488 
489 /*
490  * IPsec input callback, called by the transform callback. Takes care of
491  * filtering and other sanity checks on the processed packet.
492  */
493 int
ipsec6_common_input_cb(struct mbuf * m,struct secasvar * sav,int skip,int protoff)494 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip,
495     int protoff)
496 {
497 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
498 	struct epoch_tracker et;
499 	struct ipsec_ctx_data ctx;
500 	struct xform_history *xh;
501 	struct secasindex *saidx;
502 	struct ip6_hdr *ip6;
503 	struct m_tag *mtag;
504 	int prot, af, sproto;
505 	int nxt, isr_prot;
506 	int error, nest;
507 	uint8_t nxt8;
508 
509 	IPSEC_ASSERT(sav != NULL, ("null SA"));
510 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
511 	saidx = &sav->sah->saidx;
512 	af = saidx->dst.sa.sa_family;
513 	IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
514 	sproto = saidx->proto;
515 	IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
516 		sproto == IPPROTO_IPCOMP,
517 		("unexpected security protocol %u", sproto));
518 
519 	NET_EPOCH_ENTER(et);
520 
521 	/* Fix IPv6 header */
522 	if (m->m_len < sizeof(struct ip6_hdr) &&
523 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
524 		DPRINTF(("%s: processing failed for SA %s/%08lx\n",
525 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
526 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
527 
528 		IPSEC_ISTAT(sproto, hdrops);
529 		error = EACCES;
530 		goto bad;
531 	}
532 
533 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_BEFORE);
534 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
535 		goto bad;
536 
537 	ip6 = mtod(m, struct ip6_hdr *);
538 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
539 
540 	/* Save protocol */
541 	m_copydata(m, protoff, 1, &nxt8);
542 	prot = nxt8;
543 
544 	/* IPv6-in-IP encapsulation */
545 	if (prot == IPPROTO_IPV6 &&
546 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
547 		if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
548 			IPSEC_ISTAT(sproto, hdrops);
549 			error = EINVAL;
550 			goto bad;
551 		}
552 		/* ip6n will now contain the inner IPv6 header. */
553 		m_striphdr(m, 0, skip);
554 		skip = 0;
555 	}
556 #ifdef INET
557 	/* IP-in-IP encapsulation */
558 	else if (prot == IPPROTO_IPIP &&
559 	    saidx->mode != IPSEC_MODE_TRANSPORT) {
560 		if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
561 			IPSEC_ISTAT(sproto, hdrops);
562 			error = EINVAL;
563 			goto bad;
564 		}
565 		/* ipn will now contain the inner IPv4 header */
566 		m_striphdr(m, 0, skip);
567 		skip = 0;
568 	}
569 #endif /* INET */
570 	else {
571 		prot = IPPROTO_IPV6; /* for correct BPF processing */
572 	}
573 
574 	/*
575 	 * Record what we've done to the packet (under what SA it was
576 	 * processed).
577 	 */
578 	if (sproto != IPPROTO_IPCOMP) {
579 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
580 		    sizeof(struct xform_history), M_NOWAIT);
581 		if (mtag == NULL) {
582 			DPRINTF(("%s: failed to get tag\n", __func__));
583 			IPSEC_ISTAT(sproto, hdrops);
584 			error = ENOMEM;
585 			goto bad;
586 		}
587 
588 		xh = (struct xform_history *)(mtag + 1);
589 		bcopy(&saidx->dst, &xh->dst, saidx->dst.sa.sa_len);
590 		xh->spi = sav->spi;
591 		xh->proto = sproto;
592 		xh->mode = saidx->mode;
593 		m_tag_prepend(m, mtag);
594 	}
595 
596 	key_sa_recordxfer(sav, m);
597 
598 #ifdef INET
599 	if (prot == IPPROTO_IPIP)
600 		af = AF_INET;
601 	else
602 #endif
603 		af = AF_INET6;
604 	IPSEC_INIT_CTX(&ctx, &m, NULL, sav, af, IPSEC_ENC_AFTER);
605 	if ((error = ipsec_run_hhooks(&ctx, HHOOK_TYPE_IPSEC_IN)) != 0)
606 		goto bad;
607 	if (skip == 0) {
608 		/*
609 		 * We stripped outer IPv6 header.
610 		 * Now we should requeue decrypted packet via netisr.
611 		 */
612 		switch (prot) {
613 #ifdef INET
614 		case IPPROTO_IPIP:
615 			isr_prot = NETISR_IP;
616 			break;
617 #endif
618 		case IPPROTO_IPV6:
619 			isr_prot = NETISR_IPV6;
620 			break;
621 		default:
622 			DPRINTF(("%s: cannot handle inner ip proto %d\n",
623 			    __func__, prot));
624 			IPSEC_ISTAT(sproto, nopf);
625 			error = EPFNOSUPPORT;
626 			goto bad;
627 		}
628 		/* Handle virtual tunneling interfaces */
629 		if (saidx->mode == IPSEC_MODE_TUNNEL)
630 			error = ipsec_if_input(m, sav, af);
631 		if (error == 0) {
632 			error = netisr_queue_src(isr_prot,
633 			    (uintptr_t)sav->spi, m);
634 			if (error) {
635 				IPSEC_ISTAT(sproto, qfull);
636 				DPRINTF(("%s: queue full; proto %u packet"
637 				    " dropped\n", __func__, sproto));
638 			}
639 		}
640 		NET_EPOCH_EXIT(et);
641 		key_freesav(&sav);
642 		return (error);
643 	}
644 	/*
645 	 * See the end of ip6_input for this logic.
646 	 * IPPROTO_IPV[46] case will be processed just like other ones
647 	 */
648 	nest = 0;
649 	nxt = nxt8;
650 	while (nxt != IPPROTO_DONE) {
651 		if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
652 			IP6STAT_INC(ip6s_toomanyhdr);
653 			error = EINVAL;
654 			goto bad;
655 		}
656 
657 		/*
658 		 * Protection against faulty packet - there should be
659 		 * more sanity checks in header chain processing.
660 		 */
661 		if (m->m_pkthdr.len < skip) {
662 			IP6STAT_INC(ip6s_tooshort);
663 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
664 			error = EINVAL;
665 			goto bad;
666 		}
667 		/*
668 		 * Enforce IPsec policy checking if we are seeing last header.
669 		 * note that we do not visit this with protocols with pcb layer
670 		 * code - like udp/tcp/raw ip.
671 		 */
672 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
673 		    ipsec6_in_reject(m, NULL)) {
674 			error = EINVAL;
675 			goto bad;
676 		}
677 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
678 	}
679 	NET_EPOCH_EXIT(et);
680 	key_freesav(&sav);
681 	return (0);
682 bad:
683 	NET_EPOCH_EXIT(et);
684 	key_freesav(&sav);
685 	if (m)
686 		m_freem(m);
687 	return (error);
688 }
689 #endif /* INET6 */
690