xref: /freebsd/sys/netipsec/ipsec_input.c (revision 4b2eaea43fec8e8792be611dea204071a10b655a)
1 /*	$FreeBSD$	*/
2 /*	$KAME: ipsec.c,v 1.103 2001/05/24 07:14:18 sakane Exp $	*/
3 
4 /*
5  * IPsec input processing.
6  */
7 
8 #include "opt_inet.h"
9 #include "opt_inet6.h"
10 #include "opt_ipsec.h"
11 
12 #include <sys/param.h>
13 #include <sys/systm.h>
14 #include <sys/malloc.h>
15 #include <sys/mbuf.h>
16 #include <sys/domain.h>
17 #include <sys/protosw.h>
18 #include <sys/socket.h>
19 #include <sys/errno.h>
20 #include <sys/syslog.h>
21 
22 #include <net/if.h>
23 #include <net/route.h>
24 #include <net/netisr.h>
25 
26 #include <netinet/in.h>
27 #include <netinet/in_systm.h>
28 #include <netinet/ip.h>
29 #include <netinet/ip_var.h>
30 #include <netinet/in_var.h>
31 
32 #include <netinet/ip6.h>
33 #ifdef INET6
34 #include <netinet6/ip6_var.h>
35 #endif
36 #include <netinet/in_pcb.h>
37 #ifdef INET6
38 #include <netinet/icmp6.h>
39 #endif
40 
41 #include <netipsec/ipsec.h>
42 #ifdef INET6
43 #include <netipsec/ipsec6.h>
44 #endif
45 #include <netipsec/ah_var.h>
46 #include <netipsec/esp.h>
47 #include <netipsec/esp_var.h>
48 #include <netipsec/ipcomp_var.h>
49 
50 #include <netipsec/key.h>
51 #include <netipsec/keydb.h>
52 
53 #include <netipsec/xform.h>
54 #include <netinet6/ip6protosw.h>
55 
56 #include <machine/in_cksum.h>
57 #include <machine/stdarg.h>
58 
59 #include <net/net_osdep.h>
60 
61 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
62 			    (p) == IPPROTO_AH ? (y)++ : (z)++)
63 
64 /*
65  * ipsec_common_input gets called when an IPsec-protected packet
66  * is received by IPv4 or IPv6.  It's job is to find the right SA
67  # and call the appropriate transform.  The transform callback
68  * takes care of further processing (like ingress filtering).
69  */
70 static int
71 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
72 {
73 	union sockaddr_union dst_address;
74 	struct secasvar *sav;
75 	u_int32_t spi;
76 	int s, error;
77 
78 	IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input,
79 		ipcompstat.ipcomps_input);
80 
81 	KASSERT(m != NULL, ("ipsec_common_input: null packet"));
82 
83 	if ((sproto == IPPROTO_ESP && !esp_enable) ||
84 	    (sproto == IPPROTO_AH && !ah_enable) ||
85 	    (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) {
86 		m_freem(m);
87 		IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops,
88 		    ipcompstat.ipcomps_pdrops);
89 		return EOPNOTSUPP;
90 	}
91 
92 	if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
93 		m_freem(m);
94 		IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
95 		    ipcompstat.ipcomps_hdrops);
96 		DPRINTF(("ipsec_common_input: packet too small\n"));
97 		return EINVAL;
98 	}
99 
100 	/* Retrieve the SPI from the relevant IPsec header */
101 	if (sproto == IPPROTO_ESP)
102 		m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
103 	else if (sproto == IPPROTO_AH)
104 		m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
105 		    (caddr_t) &spi);
106 	else if (sproto == IPPROTO_IPCOMP) {
107 		u_int16_t cpi;
108 		m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
109 		    (caddr_t) &cpi);
110 		spi = ntohl(htons(cpi));
111 	}
112 
113 	/*
114 	 * Find the SA and (indirectly) call the appropriate
115 	 * kernel crypto routine. The resulting mbuf chain is a valid
116 	 * IP packet ready to go through input processing.
117 	 */
118 	bzero(&dst_address, sizeof (dst_address));
119 	dst_address.sa.sa_family = af;
120 	switch (af) {
121 #ifdef INET
122 	case AF_INET:
123 		dst_address.sin.sin_len = sizeof(struct sockaddr_in);
124 		m_copydata(m, offsetof(struct ip, ip_dst),
125 		    sizeof(struct in_addr),
126 		    (caddr_t) &dst_address.sin.sin_addr);
127 		break;
128 #endif /* INET */
129 #ifdef INET6
130 	case AF_INET6:
131 		dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
132 		m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
133 		    sizeof(struct in6_addr),
134 		    (caddr_t) &dst_address.sin6.sin6_addr);
135 		break;
136 #endif /* INET6 */
137 	default:
138 		DPRINTF(("ipsec_common_input: unsupported protocol "
139 			"family %u\n", af));
140 		m_freem(m);
141 		IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf,
142 		    ipcompstat.ipcomps_nopf);
143 		return EPFNOSUPPORT;
144 	}
145 
146 	s = splnet();
147 
148 	/* NB: only pass dst since key_allocsa follows RFC2401 */
149 	sav = KEY_ALLOCSA(&dst_address, sproto, spi);
150 	if (sav == NULL) {
151 		DPRINTF(("ipsec_common_input: no key association found for"
152 			  " SA %s/%08lx/%u\n",
153 			  ipsec_address(&dst_address),
154 			  (u_long) ntohl(spi), sproto));
155 		IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb,
156 		    ipcompstat.ipcomps_notdb);
157 		splx(s);
158 		m_freem(m);
159 		return ENOENT;
160 	}
161 
162 	if (sav->tdb_xform == NULL) {
163 		DPRINTF(("ipsec_common_input: attempted to use uninitialized"
164 			 " SA %s/%08lx/%u\n",
165 			 ipsec_address(&dst_address),
166 			 (u_long) ntohl(spi), sproto));
167 		IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform,
168 		    ipcompstat.ipcomps_noxform);
169 		KEY_FREESAV(&sav);
170 		splx(s);
171 		m_freem(m);
172 		return ENXIO;
173 	}
174 
175 	/*
176 	 * Call appropriate transform and return -- callback takes care of
177 	 * everything else.
178 	 */
179 	error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
180 	KEY_FREESAV(&sav);
181 	splx(s);
182 	return error;
183 }
184 
185 #ifdef INET
186 /*
187  * Common input handler for IPv4 AH, ESP, and IPCOMP.
188  */
189 int
190 ipsec4_common_input(struct mbuf *m, ...)
191 {
192 	va_list ap;
193 	int off, nxt;
194 
195 	va_start(ap, m);
196 	off = va_arg(ap, int);
197 	nxt = va_arg(ap, int);
198 	va_end(ap);
199 
200 	return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
201 				  AF_INET, nxt);
202 }
203 
204 void
205 ah4_input(struct mbuf *m, int off)
206 {
207 	ipsec4_common_input(m, off, IPPROTO_AH);
208 }
209 
210 void
211 esp4_input(struct mbuf *m, int off)
212 {
213 	ipsec4_common_input(m, off, IPPROTO_ESP);
214 }
215 
216 void
217 ipcomp4_input(struct mbuf *m, int off)
218 {
219 	ipsec4_common_input(m, off, IPPROTO_IPCOMP);
220 }
221 
222 /*
223  * IPsec input callback for INET protocols.
224  * This routine is called as the transform callback.
225  * Takes care of filtering and other sanity checks on
226  * the processed packet.
227  */
228 int
229 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
230 			int skip, int protoff, struct m_tag *mt)
231 {
232 	int prot, af, sproto;
233 	struct ip *ip;
234 	struct m_tag *mtag;
235 	struct tdb_ident *tdbi;
236 	struct secasindex *saidx;
237 	int error;
238 
239 #if 0
240 	SPLASSERT(net, "ipsec4_common_input_cb");
241 #endif
242 
243 	KASSERT(m != NULL, ("ipsec4_common_input_cb: null mbuf"));
244 	KASSERT(sav != NULL, ("ipsec4_common_input_cb: null SA"));
245 	KASSERT(sav->sah != NULL, ("ipsec4_common_input_cb: null SAH"));
246 	saidx = &sav->sah->saidx;
247 	af = saidx->dst.sa.sa_family;
248 	KASSERT(af == AF_INET, ("ipsec4_common_input_cb: unexpected af %u",af));
249 	sproto = saidx->proto;
250 	KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
251 		sproto == IPPROTO_IPCOMP,
252 		("ipsec4_common_input_cb: unexpected security protocol %u",
253 		sproto));
254 
255 	/* Sanity check */
256 	if (m == NULL) {
257 		DPRINTF(("ipsec4_common_input_cb: null mbuf"));
258 		IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
259 		    ipcompstat.ipcomps_badkcr);
260 		KEY_FREESAV(&sav);
261 		return EINVAL;
262 	}
263 
264 	if (skip != 0) {
265 		/* Fix IPv4 header */
266 		if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
267 			DPRINTF(("ipsec4_common_input_cb: processing failed "
268 			    "for SA %s/%08lx\n",
269 			    ipsec_address(&sav->sah->saidx.dst),
270 			    (u_long) ntohl(sav->spi)));
271 			IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
272 			    ipcompstat.ipcomps_hdrops);
273 			error = ENOBUFS;
274 			goto bad;
275 		}
276 
277 		ip = mtod(m, struct ip *);
278 		ip->ip_len = htons(m->m_pkthdr.len);
279 		ip->ip_off = htons(ip->ip_off);
280 		ip->ip_sum = 0;
281 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
282 	} else {
283 		ip = mtod(m, struct ip *);
284 	}
285 	prot = ip->ip_p;
286 
287 	/* IP-in-IP encapsulation */
288 	if (prot == IPPROTO_IPIP) {
289 		struct ip ipn;
290 
291 		/* ipn will now contain the inner IPv4 header */
292 		m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
293 		    (caddr_t) &ipn);
294 
295 #ifdef notyet
296 		/* XXX PROXY address isn't recorded in SAH */
297 		/*
298 		 * Check that the inner source address is the same as
299 		 * the proxy address, if available.
300 		 */
301 		if ((saidx->proxy.sa.sa_family == AF_INET &&
302 		    saidx->proxy.sin.sin_addr.s_addr !=
303 		    INADDR_ANY &&
304 		    ipn.ip_src.s_addr !=
305 		    saidx->proxy.sin.sin_addr.s_addr) ||
306 		    (saidx->proxy.sa.sa_family != AF_INET &&
307 			saidx->proxy.sa.sa_family != 0)) {
308 
309 			DPRINTF(("ipsec4_common_input_cb: inner "
310 			    "source address %s doesn't correspond to "
311 			    "expected proxy source %s, SA %s/%08lx\n",
312 			    inet_ntoa4(ipn.ip_src),
313 			    ipsp_address(saidx->proxy),
314 			    ipsp_address(saidx->dst),
315 			    (u_long) ntohl(sav->spi)));
316 
317 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
318 			    ahstat.ahs_pdrops,
319 			    ipcompstat.ipcomps_pdrops);
320 			error = EACCES;
321 			goto bad;
322 		}
323 #endif /*XXX*/
324 	}
325 #if INET6
326 	/* IPv6-in-IP encapsulation. */
327 	if (prot == IPPROTO_IPV6) {
328 		struct ip6_hdr ip6n;
329 
330 		/* ip6n will now contain the inner IPv6 header. */
331 		m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
332 		    (caddr_t) &ip6n);
333 
334 #ifdef notyet
335 		/*
336 		 * Check that the inner source address is the same as
337 		 * the proxy address, if available.
338 		 */
339 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
340 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
341 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
342 			&saidx->proxy.sin6.sin6_addr)) ||
343 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
344 			saidx->proxy.sa.sa_family != 0)) {
345 
346 			DPRINTF(("ipsec4_common_input_cb: inner "
347 			    "source address %s doesn't correspond to "
348 			    "expected proxy source %s, SA %s/%08lx\n",
349 			    ip6_sprintf(&ip6n.ip6_src),
350 			    ipsec_address(&saidx->proxy),
351 			    ipsec_address(&saidx->dst),
352 			    (u_long) ntohl(sav->spi)));
353 
354 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
355 			    ahstat.ahs_pdrops,
356 			    ipcompstat.ipcomps_pdrops);
357 			error = EACCES;
358 			goto bad;
359 		}
360 #endif /*XXX*/
361 	}
362 #endif /* INET6 */
363 
364 	/*
365 	 * Record what we've done to the packet (under what SA it was
366 	 * processed). If we've been passed an mtag, it means the packet
367 	 * was already processed by an ethernet/crypto combo card and
368 	 * thus has a tag attached with all the right information, but
369 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
370 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
371 	 */
372 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
373 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
374 		    sizeof(struct tdb_ident), M_NOWAIT);
375 		if (mtag == NULL) {
376 			DPRINTF(("ipsec4_common_input_cb: failed to get tag\n"));
377 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
378 			    ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
379 			error = ENOMEM;
380 			goto bad;
381 		}
382 
383 		tdbi = (struct tdb_ident *)(mtag + 1);
384 		bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
385 		tdbi->proto = sproto;
386 		tdbi->spi = sav->spi;
387 
388 		m_tag_prepend(m, mtag);
389 	} else {
390 		mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
391 		/* XXX do we need to mark m_flags??? */
392 	}
393 
394 	key_sa_recordxfer(sav, m);		/* record data transfer */
395 
396 	/*
397 	 * Re-dispatch via software interrupt.
398 	 */
399 	if (!IF_HANDOFF(&ipintrq, m, NULL)) {
400 		IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
401 			    ipcompstat.ipcomps_qfull);
402 
403 		DPRINTF(("ipsec4_common_input_cb: queue full; "
404 			"proto %u packet dropped\n", sproto));
405 		return ENOBUFS;
406 	}
407 	schednetisr(NETISR_IP);
408 	return 0;
409 bad:
410 	m_freem(m);
411 	return error;
412 }
413 #endif /* INET */
414 
415 #ifdef INET6
416 /* IPv6 AH wrapper. */
417 int
418 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
419 {
420 	int l = 0;
421 	int protoff;
422 	struct ip6_ext ip6e;
423 
424 	if (*offp < sizeof(struct ip6_hdr)) {
425 		DPRINTF(("ipsec6_common_input: bad offset %u\n", *offp));
426 		return IPPROTO_DONE;
427 	} else if (*offp == sizeof(struct ip6_hdr)) {
428 		protoff = offsetof(struct ip6_hdr, ip6_nxt);
429 	} else {
430 		/* Chase down the header chain... */
431 		protoff = sizeof(struct ip6_hdr);
432 
433 		do {
434 			protoff += l;
435 			m_copydata(*mp, protoff, sizeof(ip6e),
436 			    (caddr_t) &ip6e);
437 
438 			if (ip6e.ip6e_nxt == IPPROTO_AH)
439 				l = (ip6e.ip6e_len + 2) << 2;
440 			else
441 				l = (ip6e.ip6e_len + 1) << 3;
442 			KASSERT(l > 0, ("ah6_input: l went zero or negative"));
443 		} while (protoff + l < *offp);
444 
445 		/* Malformed packet check */
446 		if (protoff + l != *offp) {
447 			DPRINTF(("ipsec6_common_input: bad packet header chain, "
448 				"protoff %u, l %u, off %u\n", protoff, l, *offp));
449 			IPSEC_ISTAT(proto, espstat.esps_hdrops,
450 				    ahstat.ahs_hdrops,
451 				    ipcompstat.ipcomps_hdrops);
452 			m_freem(*mp);
453 			*mp = NULL;
454 			return IPPROTO_DONE;
455 		}
456 		protoff += offsetof(struct ip6_ext, ip6e_nxt);
457 	}
458 	(void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
459 	return IPPROTO_DONE;
460 }
461 
462 void
463 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
464 {
465 	if (sa->sa_family != AF_INET6 ||
466 	    sa->sa_len != sizeof(struct sockaddr_in6))
467 		return;
468 	if ((unsigned)cmd >= PRC_NCMDS)
469 		return;
470 
471 	/* if the parameter is from icmp6, decode it. */
472 	if (d !=  NULL) {
473 		struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
474 		struct mbuf *m = ip6cp->ip6c_m;
475 		int off = ip6cp->ip6c_off;
476 
477 		struct ip6ctlparam ip6cp1;
478 
479 		/*
480 		 * Notify the error to all possible sockets via pfctlinput2.
481 		 * Since the upper layer information (such as protocol type,
482 		 * source and destination ports) is embedded in the encrypted
483 		 * data and might have been cut, we can't directly call
484 		 * an upper layer ctlinput function. However, the pcbnotify
485 		 * function will consider source and destination addresses
486 		 * as well as the flow info value, and may be able to find
487 		 * some PCB that should be notified.
488 		 * Although pfctlinput2 will call esp6_ctlinput(), there is
489 		 * no possibility of an infinite loop of function calls,
490 		 * because we don't pass the inner IPv6 header.
491 		 */
492 		bzero(&ip6cp1, sizeof(ip6cp1));
493 		ip6cp1.ip6c_src = ip6cp->ip6c_src;
494 		pfctlinput2(cmd, sa, (void *)&ip6cp1);
495 
496 		/*
497 		 * Then go to special cases that need ESP header information.
498 		 * XXX: We assume that when ip6 is non NULL,
499 		 * M and OFF are valid.
500 		 */
501 
502 		if (cmd == PRC_MSGSIZE) {
503 			struct secasvar *sav;
504 			u_int32_t spi;
505 			int valid;
506 
507 			/* check header length before using m_copydata */
508 			if (m->m_pkthdr.len < off + sizeof (struct esp))
509 				return;
510 			m_copydata(m, off + offsetof(struct esp, esp_spi),
511 				sizeof(u_int32_t), (caddr_t) &spi);
512 			/*
513 			 * Check to see if we have a valid SA corresponding to
514 			 * the address in the ICMP message payload.
515 			 */
516 			sav = KEY_ALLOCSA((union sockaddr_union *)sa,
517 					IPPROTO_ESP, spi);
518 			valid = (sav != NULL);
519 			if (sav)
520 				KEY_FREESAV(&sav);
521 
522 			/* XXX Further validation? */
523 
524 			/*
525 			 * Depending on whether the SA is "valid" and
526 			 * routing table size (mtudisc_{hi,lo}wat), we will:
527 			 * - recalcurate the new MTU and create the
528 			 *   corresponding routing entry, or
529 			 * - ignore the MTU change notification.
530 			 */
531 			icmp6_mtudisc_update(ip6cp, valid);
532 		}
533 	} else {
534 		/* we normally notify any pcb here */
535 	}
536 }
537 
538 /*
539  * IPsec input callback, called by the transform callback. Takes care of
540  * filtering and other sanity checks on the processed packet.
541  */
542 int
543 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
544     struct m_tag *mt)
545 {
546 	int prot, af, sproto;
547 	struct ip6_hdr *ip6;
548 	struct m_tag *mtag;
549 	struct tdb_ident *tdbi;
550 	struct secasindex *saidx;
551 	int nxt;
552 	u_int8_t nxt8;
553 	int error, nest;
554 
555 	KASSERT(m != NULL, ("ipsec6_common_input_cb: null mbuf"));
556 	KASSERT(sav != NULL, ("ipsec6_common_input_cb: null SA"));
557 	KASSERT(sav->sah != NULL, ("ipsec6_common_input_cb: null SAH"));
558 	saidx = &sav->sah->saidx;
559 	af = saidx->dst.sa.sa_family;
560 	KASSERT(af == AF_INET6,
561 		("ipsec6_common_input_cb: unexpected af %u", af));
562 	sproto = saidx->proto;
563 	KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
564 		sproto == IPPROTO_IPCOMP,
565 		("ipsec6_common_input_cb: unexpected security protocol %u",
566 		sproto));
567 
568 	/* Sanity check */
569 	if (m == NULL) {
570 		DPRINTF(("ipsec4_common_input_cb: null mbuf"));
571 		IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
572 		    ipcompstat.ipcomps_badkcr);
573 		error = EINVAL;
574 		goto bad;
575 	}
576 
577 	/* Fix IPv6 header */
578 	if (m->m_len < sizeof(struct ip6_hdr) &&
579 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
580 
581 		DPRINTF(("ipsec_common_input_cb: processing failed "
582 		    "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst),
583 		    (u_long) ntohl(sav->spi)));
584 
585 		IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
586 		    ipcompstat.ipcomps_hdrops);
587 		error = EACCES;
588 		goto bad;
589 	}
590 
591 	ip6 = mtod(m, struct ip6_hdr *);
592 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
593 
594 	/* Save protocol */
595 	m_copydata(m, protoff, 1, (unsigned char *) &prot);
596 
597 #ifdef INET
598 	/* IP-in-IP encapsulation */
599 	if (prot == IPPROTO_IPIP) {
600 		struct ip ipn;
601 
602 		/* ipn will now contain the inner IPv4 header */
603 		m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
604 
605 #ifdef notyet
606 		/*
607 		 * Check that the inner source address is the same as
608 		 * the proxy address, if available.
609 		 */
610 		if ((saidx->proxy.sa.sa_family == AF_INET &&
611 		    saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
612 		    ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
613 		    (saidx->proxy.sa.sa_family != AF_INET &&
614 			saidx->proxy.sa.sa_family != 0)) {
615 
616 			DPRINTF(("ipsec_common_input_cb: inner "
617 			    "source address %s doesn't correspond to "
618 			    "expected proxy source %s, SA %s/%08lx\n",
619 			    inet_ntoa4(ipn.ip_src),
620 			    ipsec_address(&saidx->proxy),
621 			    ipsec_address(&saidx->dst),
622 			    (u_long) ntohl(sav->spi)));
623 
624 			IPSEC_ISTATsproto, (espstat.esps_pdrops,
625 			    ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
626 			error = EACCES;
627 			goto bad;
628 		}
629 #endif /*XXX*/
630 	}
631 #endif /* INET */
632 
633 	/* IPv6-in-IP encapsulation */
634 	if (prot == IPPROTO_IPV6) {
635 		struct ip6_hdr ip6n;
636 
637 		/* ip6n will now contain the inner IPv6 header. */
638 		m_copydata(m, skip, sizeof(struct ip6_hdr),
639 		    (caddr_t) &ip6n);
640 
641 #ifdef notyet
642 		/*
643 		 * Check that the inner source address is the same as
644 		 * the proxy address, if available.
645 		 */
646 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
647 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
648 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
649 			&saidx->proxy.sin6.sin6_addr)) ||
650 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
651 			saidx->proxy.sa.sa_family != 0)) {
652 
653 			DPRINTF(("ipsec_common_input_cb: inner "
654 			    "source address %s doesn't correspond to "
655 			    "expected proxy source %s, SA %s/%08lx\n",
656 			    ip6_sprintf(&ip6n.ip6_src),
657 			    ipsec_address(&saidx->proxy),
658 			    ipsec_address(&saidx->dst),
659 			    (u_long) ntohl(sav->spi)));
660 
661 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
662 			    ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
663 			error = EACCES;
664 			goto bad;
665 		}
666 #endif /*XXX*/
667 	}
668 
669 	/*
670 	 * Record what we've done to the packet (under what SA it was
671 	 * processed). If we've been passed an mtag, it means the packet
672 	 * was already processed by an ethernet/crypto combo card and
673 	 * thus has a tag attached with all the right information, but
674 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
675 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
676 	 */
677 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
678 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
679 		    sizeof(struct tdb_ident), M_NOWAIT);
680 		if (mtag == NULL) {
681 			DPRINTF(("ipsec_common_input_cb: failed to "
682 			    "get tag\n"));
683 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
684 			    ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
685 			error = ENOMEM;
686 			goto bad;
687 		}
688 
689 		tdbi = (struct tdb_ident *)(mtag + 1);
690 		bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
691 		tdbi->proto = sproto;
692 		tdbi->spi = sav->spi;
693 
694 		m_tag_prepend(m, mtag);
695 	} else {
696 		mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
697 		/* XXX do we need to mark m_flags??? */
698 	}
699 
700 	key_sa_recordxfer(sav, m);
701 
702 	/* Retrieve new protocol */
703 	m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
704 
705 	/*
706 	 * See the end of ip6_input for this logic.
707 	 * IPPROTO_IPV[46] case will be processed just like other ones
708 	 */
709 	nest = 0;
710 	nxt = nxt8;
711 	while (nxt != IPPROTO_DONE) {
712 		if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
713 			ip6stat.ip6s_toomanyhdr++;
714 			error = EINVAL;
715 			goto bad;
716 		}
717 
718 		/*
719 		 * Protection against faulty packet - there should be
720 		 * more sanity checks in header chain processing.
721 		 */
722 		if (m->m_pkthdr.len < skip) {
723 			ip6stat.ip6s_tooshort++;
724 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
725 			error = EINVAL;
726 			goto bad;
727 		}
728 		/*
729 		 * Enforce IPsec policy checking if we are seeing last header.
730 		 * note that we do not visit this with protocols with pcb layer
731 		 * code - like udp/tcp/raw ip.
732 		 */
733 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
734 		    ipsec6_in_reject(m, NULL)) {
735 			error = EINVAL;
736 			goto bad;
737 		}
738 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
739 	}
740 	return 0;
741 bad:
742 	if (m)
743 		m_freem(m);
744 	return error;
745 }
746 #endif /* INET6 */
747