xref: /netbsd-src/sys/netipsec/ipsec_output.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: ipsec_output.c,v 1.24 2007/12/09 18:27:39 degroote Exp $	*/
2 
3 /*-
4  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD: /repoman/r/ncvs/src/sys/netipsec/ipsec_output.c,v 1.3.2.2 2003/03/28 20:32:53 sam Exp $
29  */
30 
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: ipsec_output.c,v 1.24 2007/12/09 18:27:39 degroote Exp $");
33 
34 /*
35  * IPsec output processing.
36  */
37 #include "opt_inet.h"
38 #ifdef __FreeBSD__
39 #include "opt_inet6.h"
40 #endif
41 #include "opt_ipsec.h"
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/mbuf.h>
46 #include <sys/domain.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
49 #include <sys/errno.h>
50 #include <sys/syslog.h>
51 
52 #include <net/if.h>
53 #include <net/route.h>
54 
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/ip_var.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip_ecn.h>
61 #ifdef INET6
62 #  ifdef __FreeBSD__
63 #  include <netinet6/ip6_ecn.h>
64 #  endif
65 #endif
66 
67 #include <netinet/ip6.h>
68 #ifdef INET6
69 #include <netinet6/ip6_var.h>
70 #endif
71 #include <netinet/in_pcb.h>
72 #ifdef INET6
73 #include <netinet/icmp6.h>
74 #endif
75 #ifdef IPSEC_NAT_T
76 #include <netinet/udp.h>
77 #endif
78 
79 #include <netipsec/ipsec.h>
80 #include <netipsec/ipsec_var.h>
81 #ifdef INET6
82 #include <netipsec/ipsec6.h>
83 #endif
84 #include <netipsec/ah_var.h>
85 #include <netipsec/esp_var.h>
86 #include <netipsec/ipcomp_var.h>
87 
88 #include <netipsec/xform.h>
89 
90 #include <netipsec/key.h>
91 #include <netipsec/keydb.h>
92 #include <netipsec/key_debug.h>
93 #include <netipsec/ipsec_osdep.h>
94 
95 #include <net/net_osdep.h>		/* ovbcopy() in ipsec6_encapsulate() */
96 
97 int
98 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
99 {
100 	struct tdb_ident *tdbi;
101 	struct m_tag *mtag;
102 	struct secasvar *sav;
103 	struct secasindex *saidx;
104 	int error;
105 #ifdef INET
106 	struct ip * ip;
107 #endif /* INET */
108 #ifdef INET6
109 	struct ip6_hdr * ip6;
110 #endif /* INET6 */
111 #ifdef IPSEC_NAT_T
112 	struct mbuf * mo;
113 	struct udphdr *udp = NULL;
114 	uint64_t * data = NULL;
115 	int hlen, roff;
116 #endif /* IPSEC_NAT_T */
117 
118 	IPSEC_SPLASSERT_SOFTNET("ipsec_process_done");
119 
120 	IPSEC_ASSERT(m != NULL, ("ipsec_process_done: null mbuf"));
121 	IPSEC_ASSERT(isr != NULL, ("ipsec_process_done: null ISR"));
122 	sav = isr->sav;
123 	IPSEC_ASSERT(sav != NULL, ("ipsec_process_done: null SA"));
124 	IPSEC_ASSERT(sav->sah != NULL, ("ipsec_process_done: null SAH"));
125 
126 	saidx = &sav->sah->saidx;
127 
128 #ifdef IPSEC_NAT_T
129 	if(sav->natt_type != 0) {
130 		ip = mtod(m, struct ip *);
131 
132 		hlen = sizeof(struct udphdr);
133 		if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
134 			hlen += sizeof(uint64_t);
135 
136 		mo = m_makespace(m, sizeof(struct ip), hlen, &roff);
137 		if (mo == NULL) {
138 			DPRINTF(("ipsec_process_done : failed to inject"
139 				 "%u byte UDP for SA %s/%08lx\n",
140 					 hlen, ipsec_address(&saidx->dst),
141 					 (u_long) ntohl(sav->spi)));
142 			error = ENOBUFS;
143 			goto bad;
144 		}
145 
146 		udp = (struct udphdr*) (mtod(mo, char*) + roff);
147 		data = (uint64_t*) (udp + 1);
148 
149 		if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
150 			*data = 0; /* NON-IKE Marker */
151 
152 		if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
153 			udp->uh_sport = htons(UDP_ENCAP_ESPINUDP_PORT);
154 		else
155 			udp->uh_sport = key_portfromsaddr(&saidx->src);
156 
157 		udp->uh_dport = key_portfromsaddr(&saidx->dst);
158 		udp->uh_sum = 0;
159        	udp->uh_ulen = htons(m->m_pkthdr.len - (ip->ip_hl << 2));
160 	}
161 #endif /* IPSEC_NAT_T */
162 
163 	switch (saidx->dst.sa.sa_family) {
164 #ifdef INET
165 	case AF_INET:
166 		/* Fix the header length, for AH processing. */
167 		ip = mtod(m, struct ip *);
168 		ip->ip_len = htons(m->m_pkthdr.len);
169 #ifdef IPSEC_NAT_T
170 		if (sav->natt_type != 0)
171 			ip->ip_p = IPPROTO_UDP;
172 #endif /* IPSEC_NAT_T */
173 		break;
174 #endif /* INET */
175 #ifdef INET6
176 	case AF_INET6:
177 		/* Fix the header length, for AH processing. */
178 		if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
179 			error = ENXIO;
180 			goto bad;
181 		}
182 		if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
183 			/* No jumbogram support. */
184 			error = ENXIO;	/*?*/
185 			goto bad;
186 		}
187 		ip6 = mtod(m, struct ip6_hdr *);
188 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
189 #ifdef IPSEC_NAT_T
190 		if (sav->natt_type != 0)
191 			ip6->ip6_nxt = IPPROTO_UDP;
192 #endif /* IPSEC_NAT_T */
193 		break;
194 #endif /* INET6 */
195 	default:
196 		DPRINTF(("ipsec_process_done: unknown protocol family %u\n",
197 		    saidx->dst.sa.sa_family));
198 		error = ENXIO;
199 		goto bad;
200 	}
201 
202 	/*
203 	 * Add a record of what we've done or what needs to be done to the
204 	 * packet.
205 	 */
206 	mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
207 			sizeof(struct tdb_ident), M_NOWAIT);
208 	if (mtag == NULL) {
209 		DPRINTF(("ipsec_process_done: could not get packet tag\n"));
210 		error = ENOMEM;
211 		goto bad;
212 	}
213 
214 	tdbi = (struct tdb_ident *)(mtag + 1);
215 	tdbi->dst = saidx->dst;
216 	tdbi->proto = saidx->proto;
217 	tdbi->spi = sav->spi;
218 	m_tag_prepend(m, mtag);
219 
220 	/*
221 	 * If there's another (bundled) SA to apply, do so.
222 	 * Note that this puts a burden on the kernel stack size.
223 	 * If this is a problem we'll need to introduce a queue
224 	 * to set the packet on so we can unwind the stack before
225 	 * doing further processing.
226 	 */
227 	if (isr->next) {
228 		newipsecstat.ips_out_bundlesa++;
229         switch ( saidx->dst.sa.sa_family ) {
230 #ifdef INET
231         case AF_INET:
232 			return ipsec4_process_packet(m, isr->next, 0,0);
233 #endif /* INET */
234 #ifdef INET6
235 		case AF_INET6:
236         	return ipsec6_process_packet(m,isr->next);
237 #endif /* INET6 */
238 		default :
239 			DPRINTF(("ipsec_process_done: unknown protocol family %u\n",
240                                saidx->dst.sa.sa_family));
241 			error = ENXIO;
242 			goto bad;
243         }
244 	}
245 
246 	/*
247 	 * We're done with IPsec processing, transmit the packet using the
248 	 * appropriate network protocol (IP or IPv6). SPD lookup will be
249 	 * performed again there.
250 	 */
251 	switch (saidx->dst.sa.sa_family) {
252 #ifdef INET
253 	case AF_INET:
254 		ip = mtod(m, struct ip *);
255 #ifdef __FreeBSD__
256 		/* FreeBSD ip_output() expects ip_len, ip_off in host endian */
257 		ip->ip_len = ntohs(ip->ip_len);
258 		ip->ip_off = ntohs(ip->ip_off);
259 #endif /* __FreeBSD_ */
260 		return ip_output(m, NULL, NULL, IP_RAWOUTPUT,
261 		    (struct ip_moptions *)NULL, (struct socket *)NULL);
262 
263 #endif /* INET */
264 #ifdef INET6
265 	case AF_INET6:
266 		/*
267 		 * We don't need massage, IPv6 header fields are always in
268 		 * net endian.
269 		 */
270 		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
271 #endif /* INET6 */
272 	}
273 	panic("ipsec_process_done");
274 bad:
275 	m_freem(m);
276 	KEY_FREESAV(&sav);
277 	return (error);
278 }
279 
280 static struct ipsecrequest *
281 ipsec_nextisr(
282 	struct mbuf *m,
283 	struct ipsecrequest *isr,
284 	int af,
285 	struct secasindex *saidx,
286 	int *error
287 )
288 {
289 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
290 			    isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
291 	struct secasvar *sav;
292 
293 	IPSEC_SPLASSERT_SOFTNET("ipsec_nextisr");
294 	IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
295 		("ipsec_nextisr: invalid address family %u", af));
296 again:
297 	/*
298 	 * Craft SA index to search for proper SA.  Note that
299 	 * we only fillin unspecified SA peers for transport
300 	 * mode; for tunnel mode they must already be filled in.
301 	 */
302 	*saidx = isr->saidx;
303 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
304 		/* Fillin unspecified SA peers only for transport mode */
305 		if (af == AF_INET) {
306 			struct sockaddr_in *sin;
307 			struct ip *ip = mtod(m, struct ip *);
308 
309 			if (saidx->src.sa.sa_len == 0) {
310 				sin = &saidx->src.sin;
311 				sin->sin_len = sizeof(*sin);
312 				sin->sin_family = AF_INET;
313 				sin->sin_port = IPSEC_PORT_ANY;
314 				sin->sin_addr = ip->ip_src;
315 			}
316 			if (saidx->dst.sa.sa_len == 0) {
317 				sin = &saidx->dst.sin;
318 				sin->sin_len = sizeof(*sin);
319 				sin->sin_family = AF_INET;
320 				sin->sin_port = IPSEC_PORT_ANY;
321 				sin->sin_addr = ip->ip_dst;
322 			}
323 		} else {
324 			struct sockaddr_in6 *sin6;
325 			struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
326 
327 			if (saidx->src.sin6.sin6_len == 0) {
328 				sin6 = (struct sockaddr_in6 *)&saidx->src;
329 				sin6->sin6_len = sizeof(*sin6);
330 				sin6->sin6_family = AF_INET6;
331 				sin6->sin6_port = IPSEC_PORT_ANY;
332 				sin6->sin6_addr = ip6->ip6_src;
333 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
334 					/* fix scope id for comparing SPD */
335 					sin6->sin6_addr.s6_addr16[1] = 0;
336 					sin6->sin6_scope_id =
337 					    ntohs(ip6->ip6_src.s6_addr16[1]);
338 				}
339 			}
340 			if (saidx->dst.sin6.sin6_len == 0) {
341 				sin6 = (struct sockaddr_in6 *)&saidx->dst;
342 				sin6->sin6_len = sizeof(*sin6);
343 				sin6->sin6_family = AF_INET6;
344 				sin6->sin6_port = IPSEC_PORT_ANY;
345 				sin6->sin6_addr = ip6->ip6_dst;
346 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
347 					/* fix scope id for comparing SPD */
348 					sin6->sin6_addr.s6_addr16[1] = 0;
349 					sin6->sin6_scope_id =
350 					    ntohs(ip6->ip6_dst.s6_addr16[1]);
351 				}
352 			}
353 		}
354 	}
355 
356 	/*
357 	 * Lookup SA and validate it.
358 	 */
359 	*error = key_checkrequest(isr, saidx);
360 	if (*error != 0) {
361 		/*
362 		 * IPsec processing is required, but no SA found.
363 		 * I assume that key_acquire() had been called
364 		 * to get/establish the SA. Here I discard
365 		 * this packet because it is responsibility for
366 		 * upper layer to retransmit the packet.
367 		 */
368 		newipsecstat.ips_out_nosa++;
369 		goto bad;
370 	}
371 	sav = isr->sav;
372 	if (sav == NULL) {		/* XXX valid return */
373 		IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
374 			("ipsec_nextisr: no SA found, but required; level %u",
375 			ipsec_get_reqlevel(isr)));
376 		isr = isr->next;
377 		if (isr == NULL) {
378 			/*XXXstatistic??*/
379 			*error = EINVAL;		/*XXX*/
380 			return isr;
381 		}
382 		goto again;
383 	}
384 
385 	/*
386 	 * Check system global policy controls.
387 	 */
388 	if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
389 	    (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
390 	    (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
391 		DPRINTF(("ipsec_nextisr: IPsec outbound packet dropped due"
392 			" to policy (check your sysctls)\n"));
393 		IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
394 		    ipcompstat.ipcomps_pdrops);
395 		*error = EHOSTUNREACH;
396 		goto bad;
397 	}
398 
399 	/*
400 	 * Sanity check the SA contents for the caller
401 	 * before they invoke the xform output method.
402 	 */
403 	if (sav->tdb_xform == NULL) {
404 		DPRINTF(("ipsec_nextisr: no transform for SA\n"));
405 		IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
406 		    ipcompstat.ipcomps_noxform);
407 		*error = EHOSTUNREACH;
408 		goto bad;
409 	}
410 	return isr;
411 bad:
412 	IPSEC_ASSERT(*error != 0, ("ipsec_nextisr: error return w/ no error code"));
413 	return NULL;
414 #undef IPSEC_OSTAT
415 }
416 
417 #ifdef INET
418 /*
419  * IPsec output logic for IPv4.
420  */
421 int
422 ipsec4_process_packet(
423     struct mbuf *m,
424     struct ipsecrequest *isr,
425     int flags,
426     int tunalready
427 )
428 {
429 	struct secasindex saidx;
430 	struct secasvar *sav;
431 	struct ip *ip;
432 	int s, error, i, off;
433 
434 	IPSEC_ASSERT(m != NULL, ("ipsec4_process_packet: null mbuf"));
435 	IPSEC_ASSERT(isr != NULL, ("ipsec4_process_packet: null isr"));
436 
437 	s = splsoftnet();			/* insure SA contents don't change */
438 
439 	isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
440 	if (isr == NULL)
441 		goto bad;
442 
443 	sav = isr->sav;
444 	if (!tunalready) {
445 		union sockaddr_union *dst = &sav->sah->saidx.dst;
446 		int setdf;
447 
448 		/*
449 		 * Collect IP_DF state from the outer header.
450 		 */
451 		if (dst->sa.sa_family == AF_INET) {
452 			if (m->m_len < sizeof (struct ip) &&
453 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
454 				error = ENOBUFS;
455 				goto bad;
456 			}
457 			ip = mtod(m, struct ip *);
458 			/* Honor system-wide control of how to handle IP_DF */
459 			switch (ip4_ipsec_dfbit) {
460 			case 0:			/* clear in outer header */
461 			case 1:			/* set in outer header */
462 				setdf = ip4_ipsec_dfbit;
463 				break;
464 			default:		/* propagate to outer header */
465 				setdf = ip->ip_off;
466 #ifndef __FreeBSD__
467 		/* On FreeBSD, ip_off and ip_len assumed in host endian. */
468 				setdf = ntohs(setdf);
469 #endif
470 				setdf = htons(setdf & IP_DF);
471 				break;
472 			}
473 		} else {
474 			ip = NULL;		/* keep compiler happy */
475 			setdf = 0;
476 		}
477 		/* Do the appropriate encapsulation, if necessary */
478 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
479 		    dst->sa.sa_family != AF_INET ||	    /* PF mismatch */
480 #if 0
481 		    (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
482 		    sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
483 #endif
484 		    (dst->sa.sa_family == AF_INET &&	    /* Proxy */
485 		     dst->sin.sin_addr.s_addr != INADDR_ANY &&
486 		     dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
487 			struct mbuf *mp;
488 
489 			/* Fix IPv4 header checksum and length */
490 			if (m->m_len < sizeof (struct ip) &&
491 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
492 				error = ENOBUFS;
493 				goto bad;
494 			}
495 			ip = mtod(m, struct ip *);
496 			ip->ip_len = htons(m->m_pkthdr.len);
497 			ip->ip_sum = 0;
498 			ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
499 
500 			/* Encapsulate the packet */
501 			error = ipip_output(m, isr, &mp, 0, 0);
502 			if (mp == NULL && !error) {
503 				/* Should never happen. */
504 				DPRINTF(("ipsec4_process_packet: ipip_output "
505 					"returns no mbuf and no error!"));
506 				error = EFAULT;
507 			}
508 			if (error) {
509 				if (mp) {
510 					/* XXX: Should never happen! */
511 					m_freem(mp);
512 				}
513 				m = NULL; /* ipip_output() already freed it */
514 				goto bad;
515 			}
516 			m = mp, mp = NULL;
517 			/*
518 			 * ipip_output clears IP_DF in the new header.  If
519 			 * we need to propagate IP_DF from the outer header,
520 			 * then we have to do it here.
521 			 *
522 			 * XXX shouldn't assume what ipip_output does.
523 			 */
524 			if (dst->sa.sa_family == AF_INET && setdf) {
525 				if (m->m_len < sizeof (struct ip) &&
526 				    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
527 					error = ENOBUFS;
528 					goto bad;
529 				}
530 				ip = mtod(m, struct ip *);
531 				ip->ip_off |= IP_OFF_CONVERT(IP_DF);
532 			}
533 		}
534 	}
535 
536 	/*
537 	 * Dispatch to the appropriate IPsec transform logic.  The
538 	 * packet will be returned for transmission after crypto
539 	 * processing, etc. are completed.  For encapsulation we
540 	 * bypass this call because of the explicit call done above
541 	 * (necessary to deal with IP_DF handling for IPv4).
542 	 *
543 	 * NB: m & sav are ``passed to caller'' who's reponsible for
544 	 *     for reclaiming their resources.
545 	 */
546 	if (sav->tdb_xform->xf_type != XF_IP4) {
547 		ip = mtod(m, struct ip *);
548 		i = ip->ip_hl << 2;
549 		off = offsetof(struct ip, ip_p);
550 		error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
551 	} else {
552 		error = ipsec_process_done(m, isr);
553 	}
554 	splx(s);
555 	return error;
556 bad:
557 	splx(s);
558 	if (m)
559 		m_freem(m);
560 	return error;
561 }
562 #endif
563 
564 #ifdef INET6
565 int
566 ipsec6_process_packet(
567 	struct mbuf *m,
568  	struct ipsecrequest *isr
569     )
570 {
571 	struct secasindex saidx;
572 	struct secasvar *sav;
573 	struct ip6_hdr *ip6;
574 	int s, error, i, off;
575 
576 	IPSEC_ASSERT(m != NULL, ("ipsec6_process_packet: null mbuf"));
577 	IPSEC_ASSERT(isr != NULL, ("ipsec6_process_packet: null isr"));
578 
579 	s = splsoftnet();   /* insure SA contents don't change */
580 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
581 	if (isr == NULL) {
582 		// XXX Should we send a notification ?
583 		goto bad;
584 	}
585 
586 	sav = isr->sav;
587 	if (sav->tdb_xform->xf_type != XF_IP4) {
588 		i = sizeof(struct ip6_hdr);
589 		off = offsetof(struct ip6_hdr, ip6_nxt);
590 		error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
591        } else {
592 		union sockaddr_union *dst = &sav->sah->saidx.dst;
593 
594         ip6 = mtod(m, struct ip6_hdr *);
595 
596 		/* Do the appropriate encapsulation, if necessary */
597 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
598                dst->sa.sa_family != AF_INET6 ||        /* PF mismatch */
599             ((dst->sa.sa_family == AF_INET6) &&
600                 (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
601                 (!IN6_ARE_ADDR_EQUAL(&dst->sin6.sin6_addr,
602                 &ip6->ip6_dst)))
603             )
604 		{
605 			struct mbuf *mp;
606             /* Fix IPv6 header payload length. */
607             if (m->m_len < sizeof(struct ip6_hdr))
608                 if ((m = m_pullup(m,sizeof(struct ip6_hdr))) == NULL)
609                    return ENOBUFS;
610 
611             if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
612                 /* No jumbogram support. */
613                 m_freem(m);
614                 return ENXIO;   /*XXX*/
615             }
616             ip6 = mtod(m, struct ip6_hdr *);
617             ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
618 
619 			/* Encapsulate the packet */
620 			error = ipip_output(m, isr, &mp, 0, 0);
621 			if (mp == NULL && !error) {
622 				/* Should never happen. */
623 				DPRINTF(("ipsec6_process_packet: ipip_output "
624 						 "returns no mbuf and no error!"));
625 				 error = EFAULT;
626 			}
627 
628 			if (error) {
629 				if (mp) {
630 					/* XXX: Should never happen! */
631 					m_freem(mp);
632 				}
633 				m = NULL; /* ipip_output() already freed it */
634 				goto bad;
635 			}
636 
637 			m = mp;
638 			mp = NULL;
639 		}
640 
641 		error = ipsec_process_done(m,isr);
642 		}
643 		splx(s);
644 		return error;
645 bad:
646 	splx(s);
647 	if (m)
648 		m_freem(m);
649 	return error;
650 }
651 #endif /*INET6*/
652