xref: /freebsd/sys/netipsec/ipsec_input.c (revision 81d1ffee089aab2652954909acbe6aadd8a1a72c)
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 (!netisr_queue(NETISR_IP, m)) {
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 	return 0;
408 bad:
409 	m_freem(m);
410 	return error;
411 }
412 #endif /* INET */
413 
414 #ifdef INET6
415 /* IPv6 AH wrapper. */
416 int
417 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
418 {
419 	int l = 0;
420 	int protoff;
421 	struct ip6_ext ip6e;
422 
423 	if (*offp < sizeof(struct ip6_hdr)) {
424 		DPRINTF(("ipsec6_common_input: bad offset %u\n", *offp));
425 		return IPPROTO_DONE;
426 	} else if (*offp == sizeof(struct ip6_hdr)) {
427 		protoff = offsetof(struct ip6_hdr, ip6_nxt);
428 	} else {
429 		/* Chase down the header chain... */
430 		protoff = sizeof(struct ip6_hdr);
431 
432 		do {
433 			protoff += l;
434 			m_copydata(*mp, protoff, sizeof(ip6e),
435 			    (caddr_t) &ip6e);
436 
437 			if (ip6e.ip6e_nxt == IPPROTO_AH)
438 				l = (ip6e.ip6e_len + 2) << 2;
439 			else
440 				l = (ip6e.ip6e_len + 1) << 3;
441 			KASSERT(l > 0, ("ah6_input: l went zero or negative"));
442 		} while (protoff + l < *offp);
443 
444 		/* Malformed packet check */
445 		if (protoff + l != *offp) {
446 			DPRINTF(("ipsec6_common_input: bad packet header chain, "
447 				"protoff %u, l %u, off %u\n", protoff, l, *offp));
448 			IPSEC_ISTAT(proto, espstat.esps_hdrops,
449 				    ahstat.ahs_hdrops,
450 				    ipcompstat.ipcomps_hdrops);
451 			m_freem(*mp);
452 			*mp = NULL;
453 			return IPPROTO_DONE;
454 		}
455 		protoff += offsetof(struct ip6_ext, ip6e_nxt);
456 	}
457 	(void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
458 	return IPPROTO_DONE;
459 }
460 
461 void
462 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
463 {
464 	if (sa->sa_family != AF_INET6 ||
465 	    sa->sa_len != sizeof(struct sockaddr_in6))
466 		return;
467 	if ((unsigned)cmd >= PRC_NCMDS)
468 		return;
469 
470 	/* if the parameter is from icmp6, decode it. */
471 	if (d !=  NULL) {
472 		struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
473 		struct mbuf *m = ip6cp->ip6c_m;
474 		int off = ip6cp->ip6c_off;
475 
476 		struct ip6ctlparam ip6cp1;
477 
478 		/*
479 		 * Notify the error to all possible sockets via pfctlinput2.
480 		 * Since the upper layer information (such as protocol type,
481 		 * source and destination ports) is embedded in the encrypted
482 		 * data and might have been cut, we can't directly call
483 		 * an upper layer ctlinput function. However, the pcbnotify
484 		 * function will consider source and destination addresses
485 		 * as well as the flow info value, and may be able to find
486 		 * some PCB that should be notified.
487 		 * Although pfctlinput2 will call esp6_ctlinput(), there is
488 		 * no possibility of an infinite loop of function calls,
489 		 * because we don't pass the inner IPv6 header.
490 		 */
491 		bzero(&ip6cp1, sizeof(ip6cp1));
492 		ip6cp1.ip6c_src = ip6cp->ip6c_src;
493 		pfctlinput2(cmd, sa, (void *)&ip6cp1);
494 
495 		/*
496 		 * Then go to special cases that need ESP header information.
497 		 * XXX: We assume that when ip6 is non NULL,
498 		 * M and OFF are valid.
499 		 */
500 
501 		if (cmd == PRC_MSGSIZE) {
502 			struct secasvar *sav;
503 			u_int32_t spi;
504 			int valid;
505 
506 			/* check header length before using m_copydata */
507 			if (m->m_pkthdr.len < off + sizeof (struct esp))
508 				return;
509 			m_copydata(m, off + offsetof(struct esp, esp_spi),
510 				sizeof(u_int32_t), (caddr_t) &spi);
511 			/*
512 			 * Check to see if we have a valid SA corresponding to
513 			 * the address in the ICMP message payload.
514 			 */
515 			sav = KEY_ALLOCSA((union sockaddr_union *)sa,
516 					IPPROTO_ESP, spi);
517 			valid = (sav != NULL);
518 			if (sav)
519 				KEY_FREESAV(&sav);
520 
521 			/* XXX Further validation? */
522 
523 			/*
524 			 * Depending on whether the SA is "valid" and
525 			 * routing table size (mtudisc_{hi,lo}wat), we will:
526 			 * - recalcurate the new MTU and create the
527 			 *   corresponding routing entry, or
528 			 * - ignore the MTU change notification.
529 			 */
530 			icmp6_mtudisc_update(ip6cp, valid);
531 		}
532 	} else {
533 		/* we normally notify any pcb here */
534 	}
535 }
536 
537 /*
538  * IPsec input callback, called by the transform callback. Takes care of
539  * filtering and other sanity checks on the processed packet.
540  */
541 int
542 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
543     struct m_tag *mt)
544 {
545 	int prot, af, sproto;
546 	struct ip6_hdr *ip6;
547 	struct m_tag *mtag;
548 	struct tdb_ident *tdbi;
549 	struct secasindex *saidx;
550 	int nxt;
551 	u_int8_t nxt8;
552 	int error, nest;
553 
554 	KASSERT(m != NULL, ("ipsec6_common_input_cb: null mbuf"));
555 	KASSERT(sav != NULL, ("ipsec6_common_input_cb: null SA"));
556 	KASSERT(sav->sah != NULL, ("ipsec6_common_input_cb: null SAH"));
557 	saidx = &sav->sah->saidx;
558 	af = saidx->dst.sa.sa_family;
559 	KASSERT(af == AF_INET6,
560 		("ipsec6_common_input_cb: unexpected af %u", af));
561 	sproto = saidx->proto;
562 	KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
563 		sproto == IPPROTO_IPCOMP,
564 		("ipsec6_common_input_cb: unexpected security protocol %u",
565 		sproto));
566 
567 	/* Sanity check */
568 	if (m == NULL) {
569 		DPRINTF(("ipsec4_common_input_cb: null mbuf"));
570 		IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
571 		    ipcompstat.ipcomps_badkcr);
572 		error = EINVAL;
573 		goto bad;
574 	}
575 
576 	/* Fix IPv6 header */
577 	if (m->m_len < sizeof(struct ip6_hdr) &&
578 	    (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
579 
580 		DPRINTF(("ipsec_common_input_cb: processing failed "
581 		    "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst),
582 		    (u_long) ntohl(sav->spi)));
583 
584 		IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
585 		    ipcompstat.ipcomps_hdrops);
586 		error = EACCES;
587 		goto bad;
588 	}
589 
590 	ip6 = mtod(m, struct ip6_hdr *);
591 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
592 
593 	/* Save protocol */
594 	m_copydata(m, protoff, 1, (unsigned char *) &prot);
595 
596 #ifdef INET
597 	/* IP-in-IP encapsulation */
598 	if (prot == IPPROTO_IPIP) {
599 		struct ip ipn;
600 
601 		/* ipn will now contain the inner IPv4 header */
602 		m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
603 
604 #ifdef notyet
605 		/*
606 		 * Check that the inner source address is the same as
607 		 * the proxy address, if available.
608 		 */
609 		if ((saidx->proxy.sa.sa_family == AF_INET &&
610 		    saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
611 		    ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
612 		    (saidx->proxy.sa.sa_family != AF_INET &&
613 			saidx->proxy.sa.sa_family != 0)) {
614 
615 			DPRINTF(("ipsec_common_input_cb: inner "
616 			    "source address %s doesn't correspond to "
617 			    "expected proxy source %s, SA %s/%08lx\n",
618 			    inet_ntoa4(ipn.ip_src),
619 			    ipsec_address(&saidx->proxy),
620 			    ipsec_address(&saidx->dst),
621 			    (u_long) ntohl(sav->spi)));
622 
623 			IPSEC_ISTATsproto, (espstat.esps_pdrops,
624 			    ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
625 			error = EACCES;
626 			goto bad;
627 		}
628 #endif /*XXX*/
629 	}
630 #endif /* INET */
631 
632 	/* IPv6-in-IP encapsulation */
633 	if (prot == IPPROTO_IPV6) {
634 		struct ip6_hdr ip6n;
635 
636 		/* ip6n will now contain the inner IPv6 header. */
637 		m_copydata(m, skip, sizeof(struct ip6_hdr),
638 		    (caddr_t) &ip6n);
639 
640 #ifdef notyet
641 		/*
642 		 * Check that the inner source address is the same as
643 		 * the proxy address, if available.
644 		 */
645 		if ((saidx->proxy.sa.sa_family == AF_INET6 &&
646 		    !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
647 		    !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
648 			&saidx->proxy.sin6.sin6_addr)) ||
649 		    (saidx->proxy.sa.sa_family != AF_INET6 &&
650 			saidx->proxy.sa.sa_family != 0)) {
651 
652 			DPRINTF(("ipsec_common_input_cb: inner "
653 			    "source address %s doesn't correspond to "
654 			    "expected proxy source %s, SA %s/%08lx\n",
655 			    ip6_sprintf(&ip6n.ip6_src),
656 			    ipsec_address(&saidx->proxy),
657 			    ipsec_address(&saidx->dst),
658 			    (u_long) ntohl(sav->spi)));
659 
660 			IPSEC_ISTAT(sproto, espstat.esps_pdrops,
661 			    ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
662 			error = EACCES;
663 			goto bad;
664 		}
665 #endif /*XXX*/
666 	}
667 
668 	/*
669 	 * Record what we've done to the packet (under what SA it was
670 	 * processed). If we've been passed an mtag, it means the packet
671 	 * was already processed by an ethernet/crypto combo card and
672 	 * thus has a tag attached with all the right information, but
673 	 * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
674 	 * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
675 	 */
676 	if (mt == NULL && sproto != IPPROTO_IPCOMP) {
677 		mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
678 		    sizeof(struct tdb_ident), M_NOWAIT);
679 		if (mtag == NULL) {
680 			DPRINTF(("ipsec_common_input_cb: failed to "
681 			    "get tag\n"));
682 			IPSEC_ISTAT(sproto, espstat.esps_hdrops,
683 			    ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
684 			error = ENOMEM;
685 			goto bad;
686 		}
687 
688 		tdbi = (struct tdb_ident *)(mtag + 1);
689 		bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
690 		tdbi->proto = sproto;
691 		tdbi->spi = sav->spi;
692 
693 		m_tag_prepend(m, mtag);
694 	} else {
695 		mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
696 		/* XXX do we need to mark m_flags??? */
697 	}
698 
699 	key_sa_recordxfer(sav, m);
700 
701 	/* Retrieve new protocol */
702 	m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
703 
704 	/*
705 	 * See the end of ip6_input for this logic.
706 	 * IPPROTO_IPV[46] case will be processed just like other ones
707 	 */
708 	nest = 0;
709 	nxt = nxt8;
710 	while (nxt != IPPROTO_DONE) {
711 		if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
712 			ip6stat.ip6s_toomanyhdr++;
713 			error = EINVAL;
714 			goto bad;
715 		}
716 
717 		/*
718 		 * Protection against faulty packet - there should be
719 		 * more sanity checks in header chain processing.
720 		 */
721 		if (m->m_pkthdr.len < skip) {
722 			ip6stat.ip6s_tooshort++;
723 			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
724 			error = EINVAL;
725 			goto bad;
726 		}
727 		/*
728 		 * Enforce IPsec policy checking if we are seeing last header.
729 		 * note that we do not visit this with protocols with pcb layer
730 		 * code - like udp/tcp/raw ip.
731 		 */
732 		if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
733 		    ipsec6_in_reject(m, NULL)) {
734 			error = EINVAL;
735 			goto bad;
736 		}
737 		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
738 	}
739 	return 0;
740 bad:
741 	if (m)
742 		m_freem(m);
743 	return error;
744 }
745 #endif /* INET6 */
746