xref: /netbsd-src/sys/netipsec/xform_ah.c (revision 1897181a7231d5fc7ab48994d1447fcbc4e13a49)
1 /*	$NetBSD: xform_ah.c,v 1.34 2012/01/10 20:01:57 drochner Exp $	*/
2 /*	$FreeBSD: src/sys/netipsec/xform_ah.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $	*/
3 /*	$OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */
4 /*
5  * The authors of this code are John Ioannidis (ji@tla.org),
6  * Angelos D. Keromytis (kermit@csd.uch.gr) and
7  * Niels Provos (provos@physnet.uni-hamburg.de).
8  *
9  * The original version of this code was written by John Ioannidis
10  * for BSD/OS in Athens, Greece, in November 1995.
11  *
12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
13  * by Angelos D. Keromytis.
14  *
15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
16  * and Niels Provos.
17  *
18  * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist.
19  *
20  * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
21  * Angelos D. Keromytis and Niels Provos.
22  * Copyright (c) 1999 Niklas Hallqvist.
23  * Copyright (c) 2001 Angelos D. Keromytis.
24  *
25  * Permission to use, copy, and modify this software with or without fee
26  * is hereby granted, provided that this entire notice is included in
27  * all copies of any software which is or includes a copy or
28  * modification of this software.
29  * You may use this code under the GNU public license if you so wish. Please
30  * contribute changes back to the authors under this freer than GPL license
31  * so that we may further the use of strong encryption without limitations to
32  * all.
33  *
34  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
35  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
36  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
37  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
38  * PURPOSE.
39  */
40 
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: xform_ah.c,v 1.34 2012/01/10 20:01:57 drochner Exp $");
43 
44 #include "opt_inet.h"
45 #ifdef __FreeBSD__
46 #include "opt_inet6.h"
47 #endif
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/mbuf.h>
52 #include <sys/socket.h>
53 #include <sys/syslog.h>
54 #include <sys/kernel.h>
55 #include <sys/sysctl.h>
56 #include <sys/socketvar.h> /* for softnet_lock */
57 
58 #include <net/if.h>
59 
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/ip.h>
63 #include <netinet/ip_ecn.h>
64 #include <netinet/ip6.h>
65 
66 #include <net/route.h>
67 #include <netipsec/ipsec.h>
68 #include <netipsec/ipsec_private.h>
69 #include <netipsec/ah.h>
70 #include <netipsec/ah_var.h>
71 #include <netipsec/xform.h>
72 
73 #ifdef INET6
74 #include <netinet6/ip6_var.h>
75 #include <netinet6/scope6_var.h>
76 #include <netipsec/ipsec6.h>
77 #  ifdef __FreeBSD__
78 #  include <netinet6/ip6_ecn.h>
79 #  endif
80 #endif
81 
82 #include <netipsec/key.h>
83 #include <netipsec/key_debug.h>
84 #include <netipsec/ipsec_osdep.h>
85 
86 #include <opencrypto/cryptodev.h>
87 
88 /*
89  * Return header size in bytes.  The old protocol did not support
90  * the replay counter; the new protocol always includes the counter.
91  */
92 #define HDRSIZE(sav) \
93 	(((sav)->flags & SADB_X_EXT_OLD) ? \
94 		sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
95 /*
96  * Return authenticator size in bytes.  The old protocol is known
97  * to use a fixed 16-byte authenticator.  The new algorithm gets
98  * this size from the xform but is (currently) always 12.
99  */
100 #define	AUTHSIZE(sav) \
101 	((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize)
102 
103 percpu_t *ahstat_percpu;
104 
105 int	ah_enable = 1;			/* control flow of packets with AH */
106 int	ip4_ah_cleartos = 1;		/* clear ip_tos when doing AH calc */
107 
108 #ifdef __FreeBSD__
109 SYSCTL_DECL(_net_inet_ah);
110 SYSCTL_INT(_net_inet_ah, OID_AUTO,
111 	ah_enable,	CTLFLAG_RW,	&ah_enable,	0, "");
112 SYSCTL_INT(_net_inet_ah, OID_AUTO,
113 	ah_cleartos,	CTLFLAG_RW,	&ip4_ah_cleartos,	0, "");
114 SYSCTL_STRUCT(_net_inet_ah, IPSECCTL_STATS,
115 	stats,		CTLFLAG_RD,	&ahstat,	ahstat, "");
116 
117 #endif /* __FreeBSD__ */
118 
119 static unsigned char ipseczeroes[256];	/* larger than an ip6 extension hdr */
120 
121 static int ah_input_cb(struct cryptop*);
122 static int ah_output_cb(struct cryptop*);
123 
124 /*
125  * NB: this is public for use by the PF_KEY support.
126  */
127 const struct auth_hash *
128 ah_algorithm_lookup(int alg)
129 {
130 	if (alg >= AH_ALG_MAX)
131 		return NULL;
132 	switch (alg) {
133 	case SADB_X_AALG_NULL:
134 		return &auth_hash_null;
135 	case SADB_AALG_MD5HMAC:
136 		return &auth_hash_hmac_md5_96;
137 	case SADB_AALG_SHA1HMAC:
138 		return &auth_hash_hmac_sha1_96;
139 	case SADB_X_AALG_RIPEMD160HMAC:
140 		return &auth_hash_hmac_ripemd_160_96;
141 	case SADB_X_AALG_MD5:
142 		return &auth_hash_key_md5;
143 	case SADB_X_AALG_SHA:
144 		return &auth_hash_key_sha1;
145 	case SADB_X_AALG_SHA2_256:
146 		return &auth_hash_hmac_sha2_256;
147 	case SADB_X_AALG_SHA2_384:
148 		return &auth_hash_hmac_sha2_384;
149 	case SADB_X_AALG_SHA2_512:
150 		return &auth_hash_hmac_sha2_512;
151 	case SADB_X_AALG_AES_XCBC_MAC:
152 		return &auth_hash_aes_xcbc_mac_96;
153 	}
154 	return NULL;
155 }
156 
157 size_t
158 ah_hdrsiz(const struct secasvar *sav)
159 {
160 	size_t size;
161 
162 	if (sav != NULL) {
163 		int authsize;
164 		IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
165 			("ah_hdrsiz: null xform"));
166 		/*XXX not right for null algorithm--does it matter??*/
167 		authsize = AUTHSIZE(sav);
168 		size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav);
169 	} else {
170 		/* default guess */
171 		size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
172 	}
173 	return size;
174 }
175 
176 /*
177  * NB: public for use by esp_init.
178  */
179 int
180 ah_init0(struct secasvar *sav, const struct xformsw *xsp,
181 	 struct cryptoini *cria)
182 {
183 	const struct auth_hash *thash;
184 	int keylen;
185 
186 	thash = ah_algorithm_lookup(sav->alg_auth);
187 	if (thash == NULL) {
188 		DPRINTF(("ah_init: unsupported authentication algorithm %u\n",
189 			sav->alg_auth));
190 		return EINVAL;
191 	}
192 	/*
193 	 * Verify the replay state block allocation is consistent with
194 	 * the protocol type.  We check here so we can make assumptions
195 	 * later during protocol processing.
196 	 */
197 	/* NB: replay state is setup elsewhere (sigh) */
198 	if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
199 		DPRINTF(("ah_init: replay state block inconsistency, "
200 			"%s algorithm %s replay state\n",
201 			(sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
202 			sav->replay == NULL ? "without" : "with"));
203 		return EINVAL;
204 	}
205 	if (sav->key_auth == NULL) {
206 		DPRINTF(("ah_init: no authentication key for %s "
207 			"algorithm\n", thash->name));
208 		return EINVAL;
209 	}
210 	keylen = _KEYLEN(sav->key_auth);
211 	if (keylen != thash->keysize && thash->keysize != 0) {
212 		DPRINTF(("ah_init: invalid keylength %d, algorithm "
213 			 "%s requires keysize %d\n",
214 			 keylen, thash->name, thash->keysize));
215 		return EINVAL;
216 	}
217 
218 	sav->tdb_xform = xsp;
219 	sav->tdb_authalgxform = thash;
220 
221 	/* Initialize crypto session. */
222 	memset(cria, 0, sizeof (*cria));
223 	cria->cri_alg = sav->tdb_authalgxform->type;
224 	cria->cri_klen = _KEYBITS(sav->key_auth);
225 	cria->cri_key = _KEYBUF(sav->key_auth);
226 
227 	return 0;
228 }
229 
230 /*
231  * ah_init() is called when an SPI is being set up.
232  */
233 static int
234 ah_init(struct secasvar *sav, const struct xformsw *xsp)
235 {
236 	struct cryptoini cria;
237 	int error;
238 
239 	error = ah_init0(sav, xsp, &cria);
240 	if (!error)
241 		error = crypto_newsession(&sav->tdb_cryptoid,
242 					   &cria, crypto_support);
243 	return error;
244 }
245 
246 /*
247  * Paranoia.
248  *
249  * NB: public for use by esp_zeroize (XXX).
250  */
251 int
252 ah_zeroize(struct secasvar *sav)
253 {
254 	int err;
255 
256 	if (sav->key_auth)
257 		memset(_KEYBUF(sav->key_auth), 0, _KEYLEN(sav->key_auth));
258 
259 	err = crypto_freesession(sav->tdb_cryptoid);
260 	sav->tdb_cryptoid = 0;
261 	sav->tdb_authalgxform = NULL;
262 	sav->tdb_xform = NULL;
263 	return err;
264 }
265 
266 /*
267  * Massage IPv4/IPv6 headers for AH processing.
268  */
269 static int
270 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
271 {
272 	struct mbuf *m = *m0;
273 	unsigned char *ptr;
274 	int off, count;
275 
276 #ifdef INET
277 	struct ip *ip;
278 #endif /* INET */
279 
280 #ifdef INET6
281 	struct ip6_ext *ip6e;
282 	struct ip6_hdr ip6;
283 	int alloc, ad, nxt;
284 #endif /* INET6 */
285 
286 	switch (proto) {
287 #ifdef INET
288 	case AF_INET:
289 		/*
290 		 * This is the least painful way of dealing with IPv4 header
291 		 * and option processing -- just make sure they're in
292 		 * contiguous memory.
293 		 */
294 		*m0 = m = m_pullup(m, skip);
295 		if (m == NULL) {
296 			DPRINTF(("ah_massage_headers: m_pullup failed\n"));
297 			return ENOBUFS;
298 		}
299 
300 		/* Fix the IP header */
301 		ip = mtod(m, struct ip *);
302 		if (ip4_ah_cleartos)
303 			ip->ip_tos = 0;
304 		ip->ip_ttl = 0;
305 		ip->ip_sum = 0;
306 		ip->ip_off = htons(ntohs(ip->ip_off) & ip4_ah_offsetmask);
307 
308 		/*
309 		 * On FreeBSD, ip_off and ip_len assumed in host endian;
310 		 * they are converted (if necessary) by ip_input().
311 		 * On NetBSD, ip_off and ip_len are in network byte order.
312 		 * They must be massaged back to network byte order
313 		 * before verifying the  HMAC. Moreover, on FreeBSD,
314 		 * we should add `skip' back into the massaged ip_len
315 		 * (presumably ip_input() deducted it before we got here?)
316 		 * whereas on NetBSD, we should not.
317 		 */
318 #ifdef __FreeBSD__
319   #define TOHOST(x) (x)
320 #else
321   #define TOHOST(x) (ntohs(x))
322 #endif
323 		if (!out) {
324 			u_int16_t inlen = TOHOST(ip->ip_len);
325 
326 #ifdef __FreeBSD__
327 			ip->ip_len = htons(inlen + skip);
328 #else  /*!__FreeBSD__ */
329 			ip->ip_len = htons(inlen);
330 #endif /*!__FreeBSD__ */
331 			DPRINTF(("ip len: skip %d, "
332 				 "in %d host %d: new: raw %d host %d\n",
333 				 skip,
334 				 inlen, TOHOST(inlen),
335 				 ip->ip_len, ntohs(ip->ip_len)));
336 
337 
338 			if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
339 				ip->ip_off  &= IP_OFF_CONVERT(IP_DF);
340 			else
341 				ip->ip_off = 0;
342 		} else {
343 			if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
344 				ip->ip_off &= IP_OFF_CONVERT(IP_DF);
345 			else
346 				ip->ip_off = 0;
347 		}
348 
349 		ptr = mtod(m, unsigned char *) + sizeof(struct ip);
350 
351 		/* IPv4 option processing */
352 		for (off = sizeof(struct ip); off < skip;) {
353 			if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
354 			    off + 1 < skip)
355 				;
356 			else {
357 				DPRINTF(("ah_massage_headers: illegal IPv4 "
358 				    "option length for option %d\n",
359 				    ptr[off]));
360 
361 				m_freem(m);
362 				return EINVAL;
363 			}
364 
365 			switch (ptr[off]) {
366 			case IPOPT_EOL:
367 				off = skip;  /* End the loop. */
368 				break;
369 
370 			case IPOPT_NOP:
371 				off++;
372 				break;
373 
374 			case IPOPT_SECURITY:	/* 0x82 */
375 			case 0x85:	/* Extended security. */
376 			case 0x86:	/* Commercial security. */
377 			case 0x94:	/* Router alert */
378 			case 0x95:	/* RFC1770 */
379 				/* Sanity check for option length. */
380 				if (ptr[off + 1] < 2) {
381 					DPRINTF(("ah_massage_headers: "
382 					    "illegal IPv4 option length for "
383 					    "option %d\n", ptr[off]));
384 
385 					m_freem(m);
386 					return EINVAL;
387 				}
388 
389 				off += ptr[off + 1];
390 				break;
391 
392 			case IPOPT_LSRR:
393 			case IPOPT_SSRR:
394 				/* Sanity check for option length. */
395 				if (ptr[off + 1] < 2) {
396 					DPRINTF(("ah_massage_headers: "
397 					    "illegal IPv4 option length for "
398 					    "option %d\n", ptr[off]));
399 
400 					m_freem(m);
401 					return EINVAL;
402 				}
403 
404 				/*
405 				 * On output, if we have either of the
406 				 * source routing options, we should
407 				 * swap the destination address of the
408 				 * IP header with the last address
409 				 * specified in the option, as that is
410 				 * what the destination's IP header
411 				 * will look like.
412 				 */
413 				if (out)
414 					bcopy(ptr + off + ptr[off + 1] -
415 					    sizeof(struct in_addr),
416 					    &(ip->ip_dst), sizeof(struct in_addr));
417 
418 				/* Fall through */
419 			default:
420 				/* Sanity check for option length. */
421 				if (ptr[off + 1] < 2) {
422 					DPRINTF(("ah_massage_headers: "
423 					    "illegal IPv4 option length for "
424 					    "option %d\n", ptr[off]));
425 					m_freem(m);
426 					return EINVAL;
427 				}
428 
429 				/* Zeroize all other options. */
430 				count = ptr[off + 1];
431 				memcpy(ptr, ipseczeroes, count);
432 				off += count;
433 				break;
434 			}
435 
436 			/* Sanity check. */
437 			if (off > skip)	{
438 				DPRINTF(("ah_massage_headers(): malformed "
439 				    "IPv4 options header\n"));
440 
441 				m_freem(m);
442 				return EINVAL;
443 			}
444 		}
445 
446 		break;
447 #endif /* INET */
448 
449 #ifdef INET6
450 	case AF_INET6:  /* Ugly... */
451 		/* Copy and "cook" the IPv6 header. */
452 		m_copydata(m, 0, sizeof(ip6), &ip6);
453 
454 		/* We don't do IPv6 Jumbograms. */
455 		if (ip6.ip6_plen == 0) {
456 			DPRINTF(("ah_massage_headers: unsupported IPv6 jumbogram\n"));
457 			m_freem(m);
458 			return EMSGSIZE;
459 		}
460 
461 		ip6.ip6_flow = 0;
462 		ip6.ip6_hlim = 0;
463 		ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
464 		ip6.ip6_vfc |= IPV6_VERSION;
465 
466 		/* Scoped address handling. */
467 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
468 			ip6.ip6_src.s6_addr16[1] = 0;
469 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
470 			ip6.ip6_dst.s6_addr16[1] = 0;
471 
472 		/* Done with IPv6 header. */
473 		m_copyback(m, 0, sizeof(struct ip6_hdr), &ip6);
474 
475 		/* Let's deal with the remaining headers (if any). */
476 		if (skip - sizeof(struct ip6_hdr) > 0) {
477 			if (m->m_len <= skip) {
478 				ptr = (unsigned char *) malloc(
479 				    skip - sizeof(struct ip6_hdr),
480 				    M_XDATA, M_NOWAIT);
481 				if (ptr == NULL) {
482 					DPRINTF(("ah_massage_headers: failed "
483 					    "to allocate memory for IPv6 "
484 					    "headers\n"));
485 					m_freem(m);
486 					return ENOBUFS;
487 				}
488 
489 				/*
490 				 * Copy all the protocol headers after
491 				 * the IPv6 header.
492 				 */
493 				m_copydata(m, sizeof(struct ip6_hdr),
494 				    skip - sizeof(struct ip6_hdr), ptr);
495 				alloc = 1;
496 			} else {
497 				/* No need to allocate memory. */
498 				ptr = mtod(m, unsigned char *) +
499 				    sizeof(struct ip6_hdr);
500 				alloc = 0;
501 			}
502 		} else
503 			break;
504 
505 		nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
506 
507 		for (off = 0; off < skip - sizeof(struct ip6_hdr);)
508 			switch (nxt) {
509 			case IPPROTO_HOPOPTS:
510 			case IPPROTO_DSTOPTS:
511 				ip6e = (struct ip6_ext *) (ptr + off);
512 
513 				/*
514 				 * Process the mutable/immutable
515 				 * options -- borrows heavily from the
516 				 * KAME code.
517 				 */
518 				for (count = off + sizeof(struct ip6_ext);
519 				     count < off + ((ip6e->ip6e_len + 1) << 3);) {
520 					if (ptr[count] == IP6OPT_PAD1) {
521 						count++;
522 						continue; /* Skip padding. */
523 					}
524 
525 					/* Sanity check. */
526 					if (count > off +
527 					    ((ip6e->ip6e_len + 1) << 3)) {
528 						m_freem(m);
529 
530 						/* Free, if we allocated. */
531 						if (alloc)
532 							free(ptr, M_XDATA);
533 						return EINVAL;
534 					}
535 
536 					ad = ptr[count + 1];
537 
538 					/* If mutable option, zeroize. */
539 					if (ptr[count] & IP6OPT_MUTABLE)
540 						memcpy(ptr + count, ipseczeroes,
541 						    ptr[count + 1]);
542 
543 					count += ad;
544 
545 					/* Sanity check. */
546 					if (count >
547 					    skip - sizeof(struct ip6_hdr)) {
548 						m_freem(m);
549 
550 						/* Free, if we allocated. */
551 						if (alloc)
552 							free(ptr, M_XDATA);
553 						return EINVAL;
554 					}
555 				}
556 
557 				/* Advance. */
558 				off += ((ip6e->ip6e_len + 1) << 3);
559 				nxt = ip6e->ip6e_nxt;
560 				break;
561 
562 			case IPPROTO_ROUTING:
563 				/*
564 				 * Always include routing headers in
565 				 * computation.
566 				 */
567 				{
568 					struct ip6_rthdr *rh;
569 
570 					ip6e = (struct ip6_ext *) (ptr + off);
571 					rh = (struct ip6_rthdr *)(ptr + off);
572 					/*
573 					 * must adjust content to make it look like
574 					 * its final form (as seen at the final
575 					 * destination).
576 					 * we only know how to massage type 0 routing
577 					 * header.
578 					 */
579 					if (out && rh->ip6r_type == IPV6_RTHDR_TYPE_0) {
580 						struct ip6_rthdr0 *rh0;
581 						struct in6_addr *addr, finaldst;
582 						int i;
583 
584 						rh0 = (struct ip6_rthdr0 *)rh;
585 						addr = (struct in6_addr *)(rh0 + 1);
586 
587 						for (i = 0; i < rh0->ip6r0_segleft; i++)
588 							in6_clearscope(&addr[i]);
589 
590 						finaldst = addr[rh0->ip6r0_segleft - 1];
591 						memmove(&addr[1], &addr[0],
592 							sizeof(struct in6_addr) *
593 							(rh0->ip6r0_segleft - 1));
594 
595 						m_copydata(m, 0, sizeof(ip6), &ip6);
596 						addr[0] = ip6.ip6_dst;
597 						ip6.ip6_dst = finaldst;
598 						m_copyback(m, 0, sizeof(ip6), &ip6);
599 
600 						rh0->ip6r0_segleft = 0;
601 					}
602 
603 					/* advance */
604 					off += ((ip6e->ip6e_len + 1) << 3);
605 					nxt = ip6e->ip6e_nxt;
606 					break;
607 				}
608 
609 			default:
610 				DPRINTF(("ah_massage_headers: unexpected "
611 				    "IPv6 header type %d", off));
612 				if (alloc)
613 					free(ptr, M_XDATA);
614 				m_freem(m);
615 				return EINVAL;
616 			}
617 
618 		/* Copyback and free, if we allocated. */
619 		if (alloc) {
620 			m_copyback(m, sizeof(struct ip6_hdr),
621 			    skip - sizeof(struct ip6_hdr), ptr);
622 			free(ptr, M_XDATA);
623 		}
624 
625 		break;
626 #endif /* INET6 */
627 	}
628 
629 	return 0;
630 }
631 
632 /*
633  * ah_input() gets called to verify that an input packet
634  * passes authentication.
635  */
636 static int
637 ah_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff)
638 {
639 	const struct auth_hash *ahx;
640 	struct tdb_ident *tdbi;
641 	struct tdb_crypto *tc;
642 	struct m_tag *mtag;
643 	struct newah *ah;
644 	int hl, rplen, authsize;
645 
646 	struct cryptodesc *crda;
647 	struct cryptop *crp;
648 
649 	IPSEC_SPLASSERT_SOFTNET("ah_input");
650 
651 	IPSEC_ASSERT(sav != NULL, ("ah_input: null SA"));
652 	IPSEC_ASSERT(sav->key_auth != NULL,
653 		("ah_input: null authentication key"));
654 	IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
655 		("ah_input: null authentication xform"));
656 
657 	/* Figure out header size. */
658 	rplen = HDRSIZE(sav);
659 
660 	/* XXX don't pullup, just copy header */
661 	IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
662 	if (ah == NULL) {
663 		DPRINTF(("ah_input: cannot pullup header\n"));
664 		AH_STATINC(AH_STAT_HDROPS);	/*XXX*/
665 		m_freem(m);
666 		return ENOBUFS;
667 	}
668 
669 	/* Check replay window, if applicable. */
670 	if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) {
671 		AH_STATINC(AH_STAT_REPLAY);
672 		DPRINTF(("ah_input: packet replay failure: %s\n",
673 			  ipsec_logsastr(sav)));
674 		m_freem(m);
675 		return ENOBUFS;
676 	}
677 
678 	/* Verify AH header length. */
679 	hl = ah->ah_len * sizeof (u_int32_t);
680 	ahx = sav->tdb_authalgxform;
681 	authsize = AUTHSIZE(sav);
682 	if (hl != authsize + rplen - sizeof (struct ah)) {
683 		DPRINTF(("ah_input: bad authenticator length %u (expecting %lu)"
684 			" for packet in SA %s/%08lx\n",
685 			hl, (u_long) (authsize + rplen - sizeof (struct ah)),
686 			ipsec_address(&sav->sah->saidx.dst),
687 			(u_long) ntohl(sav->spi)));
688 		AH_STATINC(AH_STAT_BADAUTHL);
689 		m_freem(m);
690 		return EACCES;
691 	}
692 	AH_STATADD(AH_STAT_IBYTES, m->m_pkthdr.len - skip - hl);
693 	DPRINTF(("ah_input skip %d poff %d\n"
694 		 "len: hl %d authsize %d rpl %d expect %ld\n",
695 		 skip, protoff,
696 		 hl, authsize, rplen,
697 		 (long)(authsize + rplen - sizeof(struct ah))));
698 
699 	/* Get crypto descriptors. */
700 	crp = crypto_getreq(1);
701 	if (crp == NULL) {
702 		DPRINTF(("ah_input: failed to acquire crypto descriptor\n"));
703 		AH_STATINC(AH_STAT_CRYPTO);
704 		m_freem(m);
705 		return ENOBUFS;
706 	}
707 
708 	crda = crp->crp_desc;
709 	IPSEC_ASSERT(crda != NULL, ("ah_input: null crypto descriptor"));
710 
711 	crda->crd_skip = 0;
712 	crda->crd_len = m->m_pkthdr.len;
713 	crda->crd_inject = skip + rplen;
714 
715 	/* Authentication operation. */
716 	crda->crd_alg = ahx->type;
717 	crda->crd_key = _KEYBUF(sav->key_auth);
718 	crda->crd_klen = _KEYBITS(sav->key_auth);
719 
720 	/* Find out if we've already done crypto. */
721 	for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
722 	     mtag != NULL;
723 	     mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
724 		tdbi = (struct tdb_ident *) (mtag + 1);
725 		if (tdbi->proto == sav->sah->saidx.proto &&
726 		    tdbi->spi == sav->spi &&
727 		    !memcmp(&tdbi->dst, &sav->sah->saidx.dst,
728 			  sizeof (union sockaddr_union)))
729 			break;
730 	}
731 
732 	/* Allocate IPsec-specific opaque crypto info. */
733 	if (mtag == NULL) {
734 		tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) +
735 			skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO);
736 	} else {
737 		/* Hash verification has already been done successfully. */
738 		tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto),
739 						    M_XDATA, M_NOWAIT|M_ZERO);
740 	}
741 	if (tc == NULL) {
742 		DPRINTF(("ah_input: failed to allocate tdb_crypto\n"));
743 		AH_STATINC(AH_STAT_CRYPTO);
744 		crypto_freereq(crp);
745 		m_freem(m);
746 		return ENOBUFS;
747 	}
748 
749 	/* Only save information if crypto processing is needed. */
750 	if (mtag == NULL) {
751 		int error;
752 
753 		/*
754 		 * Save the authenticator, the skipped portion of the packet,
755 		 * and the AH header.
756 		 */
757 		m_copydata(m, 0, skip + rplen + authsize, (tc + 1));
758 
759 		{
760 			u_int8_t *pppp = ((char *)(tc+1))+skip+rplen;
761 			DPRINTF(("ah_input: zeroing %d bytes of authent " \
762 		    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
763 				 authsize,
764 				 pppp[0], pppp[1], pppp[2], pppp[3],
765 				 pppp[4], pppp[5], pppp[6], pppp[7],
766 				 pppp[8], pppp[9], pppp[10], pppp[11]));
767 		}
768 
769 		/* Zeroize the authenticator on the packet. */
770 		m_copyback(m, skip + rplen, authsize, ipseczeroes);
771 
772 		/* "Massage" the packet headers for crypto processing. */
773 		error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
774 		    skip, ahx->type, 0);
775 		if (error != 0) {
776 			/* NB: mbuf is free'd by ah_massage_headers */
777 			AH_STATINC(AH_STAT_HDROPS);
778 			free(tc, M_XDATA);
779 			crypto_freereq(crp);
780 			return error;
781 		}
782 	}
783 
784 	/* Crypto operation descriptor. */
785 	crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
786 	crp->crp_flags = CRYPTO_F_IMBUF;
787 	crp->crp_buf = m;
788 	crp->crp_callback = ah_input_cb;
789 	crp->crp_sid = sav->tdb_cryptoid;
790 	crp->crp_opaque = tc;
791 
792 	/* These are passed as-is to the callback. */
793 	tc->tc_spi = sav->spi;
794 	tc->tc_dst = sav->sah->saidx.dst;
795 	tc->tc_proto = sav->sah->saidx.proto;
796 	tc->tc_nxt = ah->ah_nxt;
797 	tc->tc_protoff = protoff;
798 	tc->tc_skip = skip;
799 	tc->tc_ptr = mtag; /* Save the mtag we've identified. */
800 
801 	DPRINTF(("ah: hash over %d bytes, skip %d: "
802 		 "crda len %d skip %d inject %d\n",
803 		 crp->crp_ilen, tc->tc_skip,
804 		 crda->crd_len, crda->crd_skip, crda->crd_inject));
805 
806 	if (mtag == NULL)
807 		return crypto_dispatch(crp);
808 	else
809 		return ah_input_cb(crp);
810 }
811 
812 #ifdef INET6
813 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {		     \
814 	if (saidx->dst.sa.sa_family == AF_INET6) {			     \
815 		error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
816 	} else {							     \
817 		error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
818 	}								     \
819 } while (0)
820 #else
821 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)		     \
822 	(error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
823 #endif
824 
825 /*
826  * AH input callback from the crypto driver.
827  */
828 static int
829 ah_input_cb(struct cryptop *crp)
830 {
831 	int rplen, error, skip, protoff;
832 	unsigned char calc[AH_ALEN_MAX];
833 	struct mbuf *m;
834 	struct cryptodesc *crd;
835 	const struct auth_hash *ahx;
836 	struct tdb_crypto *tc;
837 	struct m_tag *mtag;
838 	struct secasvar *sav;
839 	struct secasindex *saidx;
840 	u_int8_t nxt;
841 	char *ptr;
842 	int s, authsize;
843 	u_int16_t dport = 0;
844 	u_int16_t sport = 0;
845 #ifdef IPSEC_NAT_T
846 	struct m_tag * tag = NULL;
847 #endif
848 
849 	crd = crp->crp_desc;
850 
851 	tc = (struct tdb_crypto *) crp->crp_opaque;
852 	IPSEC_ASSERT(tc != NULL, ("ah_input_cb: null opaque crypto data area!"));
853 	skip = tc->tc_skip;
854 	nxt = tc->tc_nxt;
855 	protoff = tc->tc_protoff;
856 	mtag = (struct m_tag *) tc->tc_ptr;
857 	m = (struct mbuf *) crp->crp_buf;
858 
859 
860 #ifdef IPSEC_NAT_T
861 	/* find the source port for NAT-T */
862 	if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) {
863 		sport = ((u_int16_t *)(tag + 1))[0];
864 		dport = ((u_int16_t *)(tag + 1))[1];
865 	}
866 #endif
867 
868 	s = splsoftnet();
869 	mutex_enter(softnet_lock);
870 
871 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport);
872 	if (sav == NULL) {
873 		AH_STATINC(AH_STAT_NOTDB);
874 		DPRINTF(("ah_input_cb: SA expired while in crypto\n"));
875 		error = ENOBUFS;		/*XXX*/
876 		goto bad;
877 	}
878 
879 	saidx = &sav->sah->saidx;
880 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
881 		saidx->dst.sa.sa_family == AF_INET6,
882 		("ah_input_cb: unexpected protocol family %u",
883 		 saidx->dst.sa.sa_family));
884 
885 	ahx = sav->tdb_authalgxform;
886 
887 	/* Check for crypto errors. */
888 	if (crp->crp_etype) {
889 		if (sav->tdb_cryptoid != 0)
890 			sav->tdb_cryptoid = crp->crp_sid;
891 
892 		if (crp->crp_etype == EAGAIN) {
893 			mutex_exit(softnet_lock);
894 			splx(s);
895 			return crypto_dispatch(crp);
896 		}
897 
898 		AH_STATINC(AH_STAT_NOXFORM);
899 		DPRINTF(("ah_input_cb: crypto error %d\n", crp->crp_etype));
900 		error = crp->crp_etype;
901 		goto bad;
902 	} else {
903 		AH_STATINC(AH_STAT_HIST + sav->alg_auth);
904 		crypto_freereq(crp);		/* No longer needed. */
905 		crp = NULL;
906 	}
907 
908 	/* Shouldn't happen... */
909 	if (m == NULL) {
910 		AH_STATINC(AH_STAT_CRYPTO);
911 		DPRINTF(("ah_input_cb: bogus returned buffer from crypto\n"));
912 		error = EINVAL;
913 		goto bad;
914 	}
915 
916 	/* Figure out header size. */
917 	rplen = HDRSIZE(sav);
918 	authsize = AUTHSIZE(sav);
919 
920 	if (ipsec_debug)
921 	  memset(calc, 0, sizeof(calc));
922 
923 	/* Copy authenticator off the packet. */
924 	m_copydata(m, skip + rplen, authsize, calc);
925 
926 	/*
927 	 * If we have an mtag, we don't need to verify the authenticator --
928 	 * it has been verified by an IPsec-aware NIC.
929 	 */
930 	if (mtag == NULL) {
931 		ptr = (char *) (tc + 1);
932 
933 		/* Verify authenticator. */
934 		if (memcmp(ptr + skip + rplen, calc, authsize)) {
935 			u_int8_t *pppp = ptr + skip+rplen;
936 			DPRINTF(("ah_input: authentication hash mismatch " \
937 			    "over %d bytes " \
938 			    "for packet in SA %s/%08lx:\n" \
939 		    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \
940 		    "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n",
941 			    authsize,
942 			    ipsec_address(&saidx->dst),
943 			    (u_long) ntohl(sav->spi),
944 				 calc[0], calc[1], calc[2], calc[3],
945 				 calc[4], calc[5], calc[6], calc[7],
946 				 calc[8], calc[9], calc[10], calc[11],
947 				 pppp[0], pppp[1], pppp[2], pppp[3],
948 				 pppp[4], pppp[5], pppp[6], pppp[7],
949 				 pppp[8], pppp[9], pppp[10], pppp[11]
950 				 ));
951 			AH_STATINC(AH_STAT_BADAUTH);
952 			error = EACCES;
953 			goto bad;
954 		}
955 
956 		/* Fix the Next Protocol field. */
957 		((u_int8_t *) ptr)[protoff] = nxt;
958 
959 		/* Copyback the saved (uncooked) network headers. */
960 		m_copyback(m, 0, skip, ptr);
961 	} else {
962 		/* Fix the Next Protocol field. */
963 		m_copyback(m, protoff, sizeof(u_int8_t), &nxt);
964 	}
965 
966 	free(tc, M_XDATA), tc = NULL;			/* No longer needed */
967 
968 	/*
969 	 * Header is now authenticated.
970 	 */
971 	m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
972 
973 	/*
974 	 * Update replay sequence number, if appropriate.
975 	 */
976 	if (sav->replay) {
977 		u_int32_t seq;
978 
979 		m_copydata(m, skip + offsetof(struct newah, ah_seq),
980 			   sizeof (seq), &seq);
981 		if (ipsec_updatereplay(ntohl(seq), sav)) {
982 			AH_STATINC(AH_STAT_REPLAY);
983 			error = ENOBUFS;			/*XXX as above*/
984 			goto bad;
985 		}
986 	}
987 
988 	/*
989 	 * Remove the AH header and authenticator from the mbuf.
990 	 */
991 	error = m_striphdr(m, skip, rplen + authsize);
992 	if (error) {
993 		DPRINTF(("ah_input_cb: mangled mbuf chain for SA %s/%08lx\n",
994 		    ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
995 
996 		AH_STATINC(AH_STAT_HDROPS);
997 		goto bad;
998 	}
999 
1000 	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
1001 
1002 	KEY_FREESAV(&sav);
1003 	mutex_exit(softnet_lock);
1004 	splx(s);
1005 	return error;
1006 bad:
1007 	if (sav)
1008 		KEY_FREESAV(&sav);
1009 	mutex_exit(softnet_lock);
1010 	splx(s);
1011 	if (m != NULL)
1012 		m_freem(m);
1013 	if (tc != NULL)
1014 		free(tc, M_XDATA);
1015 	if (crp != NULL)
1016 		crypto_freereq(crp);
1017 	return error;
1018 }
1019 
1020 /*
1021  * AH output routine, called by ipsec[46]_process_packet().
1022  */
1023 static int
1024 ah_output(
1025     struct mbuf *m,
1026     struct ipsecrequest *isr,
1027     struct mbuf **mp,
1028     int skip,
1029     int protoff
1030 )
1031 {
1032 	const struct secasvar *sav;
1033 	const struct auth_hash *ahx;
1034 	struct cryptodesc *crda;
1035 	struct tdb_crypto *tc;
1036 	struct mbuf *mi;
1037 	struct cryptop *crp;
1038 	u_int16_t iplen;
1039 	int error, rplen, authsize, maxpacketsize, roff;
1040 	u_int8_t prot;
1041 	struct newah *ah;
1042 
1043 	IPSEC_SPLASSERT_SOFTNET("ah_output");
1044 
1045 	sav = isr->sav;
1046 	IPSEC_ASSERT(sav != NULL, ("ah_output: null SA"));
1047 	ahx = sav->tdb_authalgxform;
1048 	IPSEC_ASSERT(ahx != NULL, ("ah_output: null authentication xform"));
1049 
1050 	AH_STATINC(AH_STAT_OUTPUT);
1051 
1052 	/* Figure out header size. */
1053 	rplen = HDRSIZE(sav);
1054 
1055 	/* Check for maximum packet size violations. */
1056 	switch (sav->sah->saidx.dst.sa.sa_family) {
1057 #ifdef INET
1058 	case AF_INET:
1059 		maxpacketsize = IP_MAXPACKET;
1060 		break;
1061 #endif /* INET */
1062 #ifdef INET6
1063 	case AF_INET6:
1064 		maxpacketsize = IPV6_MAXPACKET;
1065 		break;
1066 #endif /* INET6 */
1067 	default:
1068 		DPRINTF(("ah_output: unknown/unsupported protocol "
1069 		    "family %u, SA %s/%08lx\n",
1070 		    sav->sah->saidx.dst.sa.sa_family,
1071 		    ipsec_address(&sav->sah->saidx.dst),
1072 		    (u_long) ntohl(sav->spi)));
1073 		AH_STATINC(AH_STAT_NOPF);
1074 		error = EPFNOSUPPORT;
1075 		goto bad;
1076 	}
1077 	authsize = AUTHSIZE(sav);
1078 	if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) {
1079 		DPRINTF(("ah_output: packet in SA %s/%08lx got too big "
1080 		    "(len %u, max len %u)\n",
1081 		    ipsec_address(&sav->sah->saidx.dst),
1082 		    (u_long) ntohl(sav->spi),
1083 		    rplen + authsize + m->m_pkthdr.len, maxpacketsize));
1084 		AH_STATINC(AH_STAT_TOOBIG);
1085 		error = EMSGSIZE;
1086 		goto bad;
1087 	}
1088 
1089 	/* Update the counters. */
1090 	AH_STATADD(AH_STAT_OBYTES, m->m_pkthdr.len - skip);
1091 
1092 	m = m_clone(m);
1093 	if (m == NULL) {
1094 		DPRINTF(("ah_output: cannot clone mbuf chain, SA %s/%08lx\n",
1095 		    ipsec_address(&sav->sah->saidx.dst),
1096 		    (u_long) ntohl(sav->spi)));
1097 		AH_STATINC(AH_STAT_HDROPS);
1098 		error = ENOBUFS;
1099 		goto bad;
1100 	}
1101 
1102 	/* Inject AH header. */
1103 	mi = m_makespace(m, skip, rplen + authsize, &roff);
1104 	if (mi == NULL) {
1105 		DPRINTF(("ah_output: failed to inject %u byte AH header for SA "
1106 		    "%s/%08lx\n",
1107 		    rplen + authsize,
1108 		    ipsec_address(&sav->sah->saidx.dst),
1109 		    (u_long) ntohl(sav->spi)));
1110 		AH_STATINC(AH_STAT_HDROPS);	/*XXX differs from openbsd */
1111 		error = ENOBUFS;
1112 		goto bad;
1113 	}
1114 
1115 	/*
1116 	 * The AH header is guaranteed by m_makespace() to be in
1117 	 * contiguous memory, at roff bytes offset into the returned mbuf.
1118 	 */
1119 	ah = (struct newah *)(mtod(mi, char *) + roff);
1120 
1121 	/* Initialize the AH header. */
1122 	m_copydata(m, protoff, sizeof(u_int8_t), &ah->ah_nxt);
1123 	ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t);
1124 	ah->ah_reserve = 0;
1125 	ah->ah_spi = sav->spi;
1126 
1127 	/* Zeroize authenticator. */
1128 	m_copyback(m, skip + rplen, authsize, ipseczeroes);
1129 
1130 	/* Insert packet replay counter, as requested.  */
1131 	if (sav->replay) {
1132 		if (sav->replay->count == ~0 &&
1133 		    (sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
1134 			DPRINTF(("ah_output: replay counter wrapped for SA "
1135 				"%s/%08lx\n",
1136 				ipsec_address(&sav->sah->saidx.dst),
1137 				(u_long) ntohl(sav->spi)));
1138 			AH_STATINC(AH_STAT_WRAP);
1139 			error = EINVAL;
1140 			goto bad;
1141 		}
1142 #ifdef IPSEC_DEBUG
1143 		/* Emulate replay attack when ipsec_replay is TRUE. */
1144 		if (!ipsec_replay)
1145 #endif
1146 			sav->replay->count++;
1147 		ah->ah_seq = htonl(sav->replay->count);
1148 	}
1149 
1150 	/* Get crypto descriptors. */
1151 	crp = crypto_getreq(1);
1152 	if (crp == NULL) {
1153 		DPRINTF(("ah_output: failed to acquire crypto descriptors\n"));
1154 		AH_STATINC(AH_STAT_CRYPTO);
1155 		error = ENOBUFS;
1156 		goto bad;
1157 	}
1158 
1159 	crda = crp->crp_desc;
1160 
1161 	crda->crd_skip = 0;
1162 	crda->crd_inject = skip + rplen;
1163 	crda->crd_len = m->m_pkthdr.len;
1164 
1165 	/* Authentication operation. */
1166 	crda->crd_alg = ahx->type;
1167 	crda->crd_key = _KEYBUF(sav->key_auth);
1168 	crda->crd_klen = _KEYBITS(sav->key_auth);
1169 
1170 	/* Allocate IPsec-specific opaque crypto info. */
1171 	tc = (struct tdb_crypto *) malloc(
1172 		sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO);
1173 	if (tc == NULL) {
1174 		crypto_freereq(crp);
1175 		DPRINTF(("ah_output: failed to allocate tdb_crypto\n"));
1176 		AH_STATINC(AH_STAT_CRYPTO);
1177 		error = ENOBUFS;
1178 		goto bad;
1179 	}
1180 
1181 	/* Save the skipped portion of the packet. */
1182 	m_copydata(m, 0, skip, (tc + 1));
1183 
1184 	/*
1185 	 * Fix IP header length on the header used for
1186 	 * authentication. We don't need to fix the original
1187 	 * header length as it will be fixed by our caller.
1188 	 */
1189 	switch (sav->sah->saidx.dst.sa.sa_family) {
1190 #ifdef INET
1191 	case AF_INET:
1192 		bcopy(((char *)(tc + 1)) +
1193 		    offsetof(struct ip, ip_len),
1194 		    &iplen, sizeof(u_int16_t));
1195 		iplen = htons(ntohs(iplen) + rplen + authsize);
1196 		m_copyback(m, offsetof(struct ip, ip_len),
1197 		    sizeof(u_int16_t), &iplen);
1198 		break;
1199 #endif /* INET */
1200 
1201 #ifdef INET6
1202 	case AF_INET6:
1203 		bcopy(((char *)(tc + 1)) +
1204 		    offsetof(struct ip6_hdr, ip6_plen),
1205 		    &iplen, sizeof(u_int16_t));
1206 		iplen = htons(ntohs(iplen) + rplen + authsize);
1207 		m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
1208 		    sizeof(u_int16_t), &iplen);
1209 		break;
1210 #endif /* INET6 */
1211 	}
1212 
1213 	/* Fix the Next Header field in saved header. */
1214 	((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH;
1215 
1216 	/* Update the Next Protocol field in the IP header. */
1217 	prot = IPPROTO_AH;
1218 	m_copyback(m, protoff, sizeof(u_int8_t), &prot);
1219 
1220 	/* "Massage" the packet headers for crypto processing. */
1221 	error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
1222 			skip, ahx->type, 1);
1223 	if (error != 0) {
1224 		m = NULL;	/* mbuf was free'd by ah_massage_headers. */
1225 		free(tc, M_XDATA);
1226 		crypto_freereq(crp);
1227 		goto bad;
1228 	}
1229 
1230 	/* Crypto operation descriptor. */
1231 	crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
1232 	crp->crp_flags = CRYPTO_F_IMBUF;
1233 	crp->crp_buf = m;
1234 	crp->crp_callback = ah_output_cb;
1235 	crp->crp_sid = sav->tdb_cryptoid;
1236 	crp->crp_opaque = tc;
1237 
1238 	/* These are passed as-is to the callback. */
1239 	tc->tc_isr = isr;
1240 	tc->tc_spi = sav->spi;
1241 	tc->tc_dst = sav->sah->saidx.dst;
1242 	tc->tc_proto = sav->sah->saidx.proto;
1243 	tc->tc_skip = skip;
1244 	tc->tc_protoff = protoff;
1245 
1246 	return crypto_dispatch(crp);
1247 bad:
1248 	if (m)
1249 		m_freem(m);
1250 	return (error);
1251 }
1252 
1253 /*
1254  * AH output callback from the crypto driver.
1255  */
1256 static int
1257 ah_output_cb(struct cryptop *crp)
1258 {
1259 	int skip, protoff, error;
1260 	struct tdb_crypto *tc;
1261 	struct ipsecrequest *isr;
1262 	struct secasvar *sav;
1263 	struct mbuf *m;
1264 	void *ptr;
1265 	int s, err;
1266 
1267 	tc = (struct tdb_crypto *) crp->crp_opaque;
1268 	IPSEC_ASSERT(tc != NULL, ("ah_output_cb: null opaque data area!"));
1269 	skip = tc->tc_skip;
1270 	protoff = tc->tc_protoff;
1271 	ptr = (tc + 1);
1272 	m = (struct mbuf *) crp->crp_buf;
1273 
1274 	s = splsoftnet();
1275 	mutex_enter(softnet_lock);
1276 
1277 	isr = tc->tc_isr;
1278 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0);
1279 	if (sav == NULL) {
1280 		AH_STATINC(AH_STAT_NOTDB);
1281 		DPRINTF(("ah_output_cb: SA expired while in crypto\n"));
1282 		error = ENOBUFS;		/*XXX*/
1283 		goto bad;
1284 	}
1285 	IPSEC_ASSERT(isr->sav == sav, ("ah_output_cb: SA changed\n"));
1286 
1287 	/* Check for crypto errors. */
1288 	if (crp->crp_etype) {
1289 		if (sav->tdb_cryptoid != 0)
1290 			sav->tdb_cryptoid = crp->crp_sid;
1291 
1292 		if (crp->crp_etype == EAGAIN) {
1293 			KEY_FREESAV(&sav);
1294 			mutex_exit(softnet_lock);
1295 			splx(s);
1296 			return crypto_dispatch(crp);
1297 		}
1298 
1299 		AH_STATINC(AH_STAT_NOXFORM);
1300 		DPRINTF(("ah_output_cb: crypto error %d\n", crp->crp_etype));
1301 		error = crp->crp_etype;
1302 		goto bad;
1303 	}
1304 
1305 	/* Shouldn't happen... */
1306 	if (m == NULL) {
1307 		AH_STATINC(AH_STAT_CRYPTO);
1308 		DPRINTF(("ah_output_cb: bogus returned buffer from crypto\n"));
1309 		error = EINVAL;
1310 		goto bad;
1311 	}
1312 	AH_STATINC(AH_STAT_HIST + sav->alg_auth);
1313 
1314 	/*
1315 	 * Copy original headers (with the new protocol number) back
1316 	 * in place.
1317 	 */
1318 	m_copyback(m, 0, skip, ptr);
1319 
1320 	/* No longer needed. */
1321 	free(tc, M_XDATA);
1322 	crypto_freereq(crp);
1323 
1324 #ifdef IPSEC_DEBUG
1325 	/* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
1326 	if (ipsec_integrity) {
1327 		int alen;
1328 
1329 		/*
1330 		 * Corrupt HMAC if we want to test integrity verification of
1331 		 * the other side.
1332 		 */
1333 		alen = AUTHSIZE(sav);
1334 		m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes);
1335 	}
1336 #endif
1337 
1338 	/* NB: m is reclaimed by ipsec_process_done. */
1339 	err = ipsec_process_done(m, isr);
1340 	KEY_FREESAV(&sav);
1341 	mutex_exit(softnet_lock);
1342 	splx(s);
1343 	return err;
1344 bad:
1345 	if (sav)
1346 		KEY_FREESAV(&sav);
1347 	mutex_exit(softnet_lock);
1348 	splx(s);
1349 	if (m)
1350 		m_freem(m);
1351 	free(tc, M_XDATA);
1352 	crypto_freereq(crp);
1353 	return error;
1354 }
1355 
1356 static struct xformsw ah_xformsw = {
1357 	XF_AH,		XFT_AUTH,	"IPsec AH",
1358 	ah_init,	ah_zeroize,	ah_input,	ah_output,
1359 	NULL,
1360 };
1361 
1362 INITFN void
1363 ah_attach(void)
1364 {
1365 	ahstat_percpu = percpu_alloc(sizeof(uint64_t) * AH_NSTATS);
1366 	xform_register(&ah_xformsw);
1367 }
1368 
1369 #ifdef __FreeBSD__
1370 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
1371 #endif
1372