xref: /freebsd/sys/netipsec/ipsec_output.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 /*
30  * IPsec output processing.
31  */
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 #include "opt_ipsec.h"
35 #include "opt_enc.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/mbuf.h>
40 #include <sys/domain.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
43 #include <sys/errno.h>
44 #include <sys/syslog.h>
45 
46 #include <net/if.h>
47 #include <net/pfil.h>
48 #include <net/route.h>
49 
50 #include <netinet/in.h>
51 #include <netinet/in_systm.h>
52 #include <netinet/ip.h>
53 #include <netinet/ip_var.h>
54 #include <netinet/in_var.h>
55 #include <netinet/ip_ecn.h>
56 #ifdef INET6
57 #include <netinet6/ip6_ecn.h>
58 #endif
59 
60 #include <netinet/ip6.h>
61 #ifdef INET6
62 #include <netinet6/ip6_var.h>
63 #endif
64 #include <netinet/in_pcb.h>
65 #ifdef INET6
66 #include <netinet/icmp6.h>
67 #endif
68 
69 #include <netipsec/ipsec.h>
70 #ifdef INET6
71 #include <netipsec/ipsec6.h>
72 #endif
73 #include <netipsec/ah_var.h>
74 #include <netipsec/esp_var.h>
75 #include <netipsec/ipcomp_var.h>
76 
77 #include <netipsec/xform.h>
78 
79 #include <netipsec/key.h>
80 #include <netipsec/keydb.h>
81 #include <netipsec/key_debug.h>
82 
83 #include <machine/in_cksum.h>
84 
85 int
86 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
87 {
88 	struct tdb_ident *tdbi;
89 	struct m_tag *mtag;
90 	struct secasvar *sav;
91 	struct secasindex *saidx;
92 	int error;
93 
94 	IPSEC_SPLASSERT_SOFTNET(__func__);
95 
96 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
97 	IPSEC_ASSERT(isr != NULL, ("null ISR"));
98 	sav = isr->sav;
99 	IPSEC_ASSERT(sav != NULL, ("null SA"));
100 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
101 
102 	saidx = &sav->sah->saidx;
103 	switch (saidx->dst.sa.sa_family) {
104 #ifdef INET
105 	case AF_INET:
106 		/* Fix the header length, for AH processing. */
107 		mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
108 		break;
109 #endif /* INET */
110 #ifdef INET6
111 	case AF_INET6:
112 		/* Fix the header length, for AH processing. */
113 		if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
114 			error = ENXIO;
115 			goto bad;
116 		}
117 		if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
118 			/* No jumbogram support. */
119 			error = ENXIO;	/*?*/
120 			goto bad;
121 		}
122 		mtod(m, struct ip6_hdr *)->ip6_plen =
123 			htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
124 		break;
125 #endif /* INET6 */
126 	default:
127 		DPRINTF(("%s: unknown protocol family %u\n", __func__,
128 		    saidx->dst.sa.sa_family));
129 		error = ENXIO;
130 		goto bad;
131 	}
132 
133 	/*
134 	 * Add a record of what we've done or what needs to be done to the
135 	 * packet.
136 	 */
137 	mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
138 			sizeof(struct tdb_ident), M_NOWAIT);
139 	if (mtag == NULL) {
140 		DPRINTF(("%s: could not get packet tag\n", __func__));
141 		error = ENOMEM;
142 		goto bad;
143 	}
144 
145 	tdbi = (struct tdb_ident *)(mtag + 1);
146 	tdbi->dst = saidx->dst;
147 	tdbi->proto = saidx->proto;
148 	tdbi->spi = sav->spi;
149 	m_tag_prepend(m, mtag);
150 
151 	/*
152 	 * If there's another (bundled) SA to apply, do so.
153 	 * Note that this puts a burden on the kernel stack size.
154 	 * If this is a problem we'll need to introduce a queue
155 	 * to set the packet on so we can unwind the stack before
156 	 * doing further processing.
157 	 */
158 	if (isr->next) {
159 		ipsec4stat.ips_out_bundlesa++;
160 		return ipsec4_process_packet(m, isr->next, 0, 0);
161 	}
162 	key_sa_recordxfer(sav, m);		/* record data transfer */
163 
164 	/*
165 	 * We're done with IPsec processing, transmit the packet using the
166 	 * appropriate network protocol (IP or IPv6). SPD lookup will be
167 	 * performed again there.
168 	 */
169 	switch (saidx->dst.sa.sa_family) {
170 #ifdef INET
171 	struct ip *ip;
172 	case AF_INET:
173 		ip = mtod(m, struct ip *);
174 		ip->ip_len = ntohs(ip->ip_len);
175 		ip->ip_off = ntohs(ip->ip_off);
176 
177 		return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
178 #endif /* INET */
179 #ifdef INET6
180 	case AF_INET6:
181 		/*
182 		 * We don't need massage, IPv6 header fields are always in
183 		 * net endian.
184 		 */
185 		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
186 #endif /* INET6 */
187 	}
188 	panic("ipsec_process_done");
189 bad:
190 	m_freem(m);
191 	KEY_FREESAV(&sav);
192 	return (error);
193 }
194 
195 static struct ipsecrequest *
196 ipsec_nextisr(
197 	struct mbuf *m,
198 	struct ipsecrequest *isr,
199 	int af,
200 	struct secasindex *saidx,
201 	int *error
202 )
203 {
204 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
205 			    isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
206 	struct secasvar *sav;
207 
208 	IPSEC_SPLASSERT_SOFTNET(__func__);
209 	IPSECREQUEST_LOCK_ASSERT(isr);
210 
211 	IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
212 		("invalid address family %u", af));
213 again:
214 	/*
215 	 * Craft SA index to search for proper SA.  Note that
216 	 * we only fillin unspecified SA peers for transport
217 	 * mode; for tunnel mode they must already be filled in.
218 	 */
219 	*saidx = isr->saidx;
220 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
221 		/* Fillin unspecified SA peers only for transport mode */
222 		if (af == AF_INET) {
223 			struct sockaddr_in *sin;
224 			struct ip *ip = mtod(m, struct ip *);
225 
226 			if (saidx->src.sa.sa_len == 0) {
227 				sin = &saidx->src.sin;
228 				sin->sin_len = sizeof(*sin);
229 				sin->sin_family = AF_INET;
230 				sin->sin_port = IPSEC_PORT_ANY;
231 				sin->sin_addr = ip->ip_src;
232 			}
233 			if (saidx->dst.sa.sa_len == 0) {
234 				sin = &saidx->dst.sin;
235 				sin->sin_len = sizeof(*sin);
236 				sin->sin_family = AF_INET;
237 				sin->sin_port = IPSEC_PORT_ANY;
238 				sin->sin_addr = ip->ip_dst;
239 			}
240 		} else {
241 			struct sockaddr_in6 *sin6;
242 			struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
243 
244 			if (saidx->src.sin6.sin6_len == 0) {
245 				sin6 = (struct sockaddr_in6 *)&saidx->src;
246 				sin6->sin6_len = sizeof(*sin6);
247 				sin6->sin6_family = AF_INET6;
248 				sin6->sin6_port = IPSEC_PORT_ANY;
249 				sin6->sin6_addr = ip6->ip6_src;
250 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
251 					/* fix scope id for comparing SPD */
252 					sin6->sin6_addr.s6_addr16[1] = 0;
253 					sin6->sin6_scope_id =
254 					    ntohs(ip6->ip6_src.s6_addr16[1]);
255 				}
256 			}
257 			if (saidx->dst.sin6.sin6_len == 0) {
258 				sin6 = (struct sockaddr_in6 *)&saidx->dst;
259 				sin6->sin6_len = sizeof(*sin6);
260 				sin6->sin6_family = AF_INET6;
261 				sin6->sin6_port = IPSEC_PORT_ANY;
262 				sin6->sin6_addr = ip6->ip6_dst;
263 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
264 					/* fix scope id for comparing SPD */
265 					sin6->sin6_addr.s6_addr16[1] = 0;
266 					sin6->sin6_scope_id =
267 					    ntohs(ip6->ip6_dst.s6_addr16[1]);
268 				}
269 			}
270 		}
271 	}
272 
273 	/*
274 	 * Lookup SA and validate it.
275 	 */
276 	*error = key_checkrequest(isr, saidx);
277 	if (*error != 0) {
278 		/*
279 		 * IPsec processing is required, but no SA found.
280 		 * I assume that key_acquire() had been called
281 		 * to get/establish the SA. Here I discard
282 		 * this packet because it is responsibility for
283 		 * upper layer to retransmit the packet.
284 		 */
285 		ipsec4stat.ips_out_nosa++;
286 		goto bad;
287 	}
288 	sav = isr->sav;
289 	if (sav == NULL) {		/* XXX valid return */
290 		IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
291 			("no SA found, but required; level %u",
292 			ipsec_get_reqlevel(isr)));
293 		IPSECREQUEST_UNLOCK(isr);
294 		isr = isr->next;
295 		if (isr == NULL) {
296 			/*XXXstatistic??*/
297 			*error = EINVAL;		/*XXX*/
298 			return isr;
299 		}
300 		IPSECREQUEST_LOCK(isr);
301 		goto again;
302 	}
303 
304 	/*
305 	 * Check system global policy controls.
306 	 */
307 	if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
308 	    (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
309 	    (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
310 		DPRINTF(("%s: IPsec outbound packet dropped due"
311 			" to policy (check your sysctls)\n", __func__));
312 		IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
313 		    ipcompstat.ipcomps_pdrops);
314 		*error = EHOSTUNREACH;
315 		goto bad;
316 	}
317 
318 	/*
319 	 * Sanity check the SA contents for the caller
320 	 * before they invoke the xform output method.
321 	 */
322 	if (sav->tdb_xform == NULL) {
323 		DPRINTF(("%s: no transform for SA\n", __func__));
324 		IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
325 		    ipcompstat.ipcomps_noxform);
326 		*error = EHOSTUNREACH;
327 		goto bad;
328 	}
329 	return isr;
330 bad:
331 	IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
332 	IPSECREQUEST_UNLOCK(isr);
333 	return NULL;
334 #undef IPSEC_OSTAT
335 }
336 
337 #ifdef INET
338 /*
339  * IPsec output logic for IPv4.
340  */
341 int
342 ipsec4_process_packet(
343 	struct mbuf *m,
344 	struct ipsecrequest *isr,
345 	int flags,
346 	int tunalready)
347 {
348 	struct secasindex saidx;
349 	struct secasvar *sav;
350 	struct ip *ip;
351 	int error, i, off;
352 
353 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
354 	IPSEC_ASSERT(isr != NULL, ("null isr"));
355 
356 	IPSECREQUEST_LOCK(isr);		/* insure SA contents don't change */
357 
358 	isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
359 	if (isr == NULL)
360 		goto bad;
361 
362 	sav = isr->sav;
363 
364 #ifdef DEV_ENC
365 	/* pass the mbuf to enc0 for bpf processing */
366 	ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_BEFORE);
367 	/* pass the mbuf to enc0 for packet filtering */
368 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
369 		goto bad;
370 #endif
371 
372 	if (!tunalready) {
373 		union sockaddr_union *dst = &sav->sah->saidx.dst;
374 		int setdf;
375 
376 		/*
377 		 * Collect IP_DF state from the outer header.
378 		 */
379 		if (dst->sa.sa_family == AF_INET) {
380 			if (m->m_len < sizeof (struct ip) &&
381 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
382 				error = ENOBUFS;
383 				goto bad;
384 			}
385 			ip = mtod(m, struct ip *);
386 			/* Honor system-wide control of how to handle IP_DF */
387 			switch (ip4_ipsec_dfbit) {
388 			case 0:			/* clear in outer header */
389 			case 1:			/* set in outer header */
390 				setdf = ip4_ipsec_dfbit;
391 				break;
392 			default:		/* propagate to outer header */
393 				setdf = ntohs(ip->ip_off & IP_DF);
394 				break;
395 			}
396 		} else {
397 			ip = NULL;		/* keep compiler happy */
398 			setdf = 0;
399 		}
400 		/* Do the appropriate encapsulation, if necessary */
401 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
402 		    dst->sa.sa_family != AF_INET ||	    /* PF mismatch */
403 #if 0
404 		    (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
405 		    sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
406 #endif
407 		    (dst->sa.sa_family == AF_INET &&	    /* Proxy */
408 		     dst->sin.sin_addr.s_addr != INADDR_ANY &&
409 		     dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
410 			struct mbuf *mp;
411 
412 			/* Fix IPv4 header checksum and length */
413 			if (m->m_len < sizeof (struct ip) &&
414 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
415 				error = ENOBUFS;
416 				goto bad;
417 			}
418 			ip = mtod(m, struct ip *);
419 			ip->ip_len = htons(m->m_pkthdr.len);
420 			ip->ip_sum = 0;
421 #ifdef _IP_VHL
422 			if (ip->ip_vhl == IP_VHL_BORING)
423 				ip->ip_sum = in_cksum_hdr(ip);
424 			else
425 				ip->ip_sum = in_cksum(m,
426 					_IP_VHL_HL(ip->ip_vhl) << 2);
427 #else
428 			ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
429 #endif
430 
431 			/* Encapsulate the packet */
432 			error = ipip_output(m, isr, &mp, 0, 0);
433 			if (mp == NULL && !error) {
434 				/* Should never happen. */
435 				DPRINTF(("%s: ipip_output returns no mbuf and "
436 					"no error!", __func__));
437 				error = EFAULT;
438 			}
439 			if (error) {
440 				if (mp) {
441 					/* XXX: Should never happen! */
442 					m_freem(mp);
443 				}
444 				m = NULL; /* ipip_output() already freed it */
445 				goto bad;
446 			}
447 			m = mp, mp = NULL;
448 			/*
449 			 * ipip_output clears IP_DF in the new header.  If
450 			 * we need to propagate IP_DF from the outer header,
451 			 * then we have to do it here.
452 			 *
453 			 * XXX shouldn't assume what ipip_output does.
454 			 */
455 			if (dst->sa.sa_family == AF_INET && setdf) {
456 				if (m->m_len < sizeof (struct ip) &&
457 				    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
458 					error = ENOBUFS;
459 					goto bad;
460 				}
461 				ip = mtod(m, struct ip *);
462 				ip->ip_off = ntohs(ip->ip_off);
463 				ip->ip_off |= IP_DF;
464 				ip->ip_off = htons(ip->ip_off);
465 			}
466 		}
467 	}
468 
469 #ifdef DEV_ENC
470 	/* pass the mbuf to enc0 for bpf processing */
471 	ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_AFTER);
472 	/* pass the mbuf to enc0 for packet filtering */
473 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
474 		goto bad;
475 #endif
476 
477 	/*
478 	 * Dispatch to the appropriate IPsec transform logic.  The
479 	 * packet will be returned for transmission after crypto
480 	 * processing, etc. are completed.  For encapsulation we
481 	 * bypass this call because of the explicit call done above
482 	 * (necessary to deal with IP_DF handling for IPv4).
483 	 *
484 	 * NB: m & sav are ``passed to caller'' who's reponsible for
485 	 *     for reclaiming their resources.
486 	 */
487 	if (sav->tdb_xform->xf_type != XF_IP4) {
488 		ip = mtod(m, struct ip *);
489 		i = ip->ip_hl << 2;
490 		off = offsetof(struct ip, ip_p);
491 		error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
492 	} else {
493 		error = ipsec_process_done(m, isr);
494 	}
495 	IPSECREQUEST_UNLOCK(isr);
496 	return error;
497 bad:
498 	if (isr)
499 		IPSECREQUEST_UNLOCK(isr);
500 	if (m)
501 		m_freem(m);
502 	return error;
503 }
504 #endif
505 
506 #ifdef INET6
507 /*
508  * Chop IP6 header from the payload.
509  */
510 static struct mbuf *
511 ipsec6_splithdr(struct mbuf *m)
512 {
513 	struct mbuf *mh;
514 	struct ip6_hdr *ip6;
515 	int hlen;
516 
517 	IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
518 		("first mbuf too short, len %u", m->m_len));
519 	ip6 = mtod(m, struct ip6_hdr *);
520 	hlen = sizeof(struct ip6_hdr);
521 	if (m->m_len > hlen) {
522 		MGETHDR(mh, M_DONTWAIT, MT_DATA);
523 		if (!mh) {
524 			m_freem(m);
525 			return NULL;
526 		}
527 		M_MOVE_PKTHDR(mh, m);
528 		MH_ALIGN(mh, hlen);
529 		m->m_len -= hlen;
530 		m->m_data += hlen;
531 		mh->m_next = m;
532 		m = mh;
533 		m->m_len = hlen;
534 		bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
535 	} else if (m->m_len < hlen) {
536 		m = m_pullup(m, hlen);
537 		if (!m)
538 			return NULL;
539 	}
540 	return m;
541 }
542 
543 /*
544  * IPsec output logic for IPv6, transport mode.
545  */
546 int
547 ipsec6_output_trans(
548 	struct ipsec_output_state *state,
549 	u_char *nexthdrp,
550 	struct mbuf *mprev,
551 	struct secpolicy *sp,
552 	int flags,
553 	int *tun)
554 {
555 	struct ipsecrequest *isr;
556 	struct secasindex saidx;
557 	int error = 0;
558 	struct mbuf *m;
559 
560 	IPSEC_ASSERT(state != NULL, ("null state"));
561 	IPSEC_ASSERT(state->m != NULL, ("null m"));
562 	IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
563 	IPSEC_ASSERT(mprev != NULL, ("null mprev"));
564 	IPSEC_ASSERT(sp != NULL, ("null sp"));
565 	IPSEC_ASSERT(tun != NULL, ("null tun"));
566 
567 	KEYDEBUG(KEYDEBUG_IPSEC_DATA,
568 		printf("%s: applied SP\n", __func__);
569 		kdebug_secpolicy(sp));
570 
571 	isr = sp->req;
572 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
573 		/* the rest will be handled by ipsec6_output_tunnel() */
574 		*tun = 1;		/* need tunnel-mode processing */
575 		return 0;
576 	}
577 
578 	*tun = 0;
579 	m = state->m;
580 
581 	IPSECREQUEST_LOCK(isr);		/* insure SA contents don't change */
582 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
583 	if (isr == NULL) {
584 #ifdef notdef
585 		/* XXX should notification be done for all errors ? */
586 		/*
587 		 * Notify the fact that the packet is discarded
588 		 * to ourselves. I believe this is better than
589 		 * just silently discarding. (jinmei@kame.net)
590 		 * XXX: should we restrict the error to TCP packets?
591 		 * XXX: should we directly notify sockets via
592 		 *      pfctlinputs?
593 		 */
594 		icmp6_error(m, ICMP6_DST_UNREACH,
595 			    ICMP6_DST_UNREACH_ADMIN, 0);
596 		m = NULL;	/* NB: icmp6_error frees mbuf */
597 #endif
598 		goto bad;
599 	}
600 
601 	error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
602 						  sizeof (struct ip6_hdr),
603 						  offsetof(struct ip6_hdr,
604 							   ip6_nxt));
605 	IPSECREQUEST_UNLOCK(isr);
606 	return error;
607 bad:
608 	if (isr)
609 		IPSECREQUEST_UNLOCK(isr);
610 	if (m)
611 		m_freem(m);
612 	state->m = NULL;
613 	return error;
614 }
615 
616 static int
617 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
618 {
619 	struct ip6_hdr *oip6;
620 	struct ip6_hdr *ip6;
621 	size_t plen;
622 
623 	/* can't tunnel between different AFs */
624 	if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
625 	    sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
626 		m_freem(m);
627 		return EINVAL;
628 	}
629 	IPSEC_ASSERT(m->m_len == sizeof (struct ip6_hdr),
630 		("mbuf wrong size; len %u", m->m_len));
631 
632 
633 	/*
634 	 * grow the mbuf to accomodate the new IPv6 header.
635 	 */
636 	plen = m->m_pkthdr.len;
637 	if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
638 		struct mbuf *n;
639 		MGET(n, M_DONTWAIT, MT_DATA);
640 		if (!n) {
641 			m_freem(m);
642 			return ENOBUFS;
643 		}
644 		n->m_len = sizeof(struct ip6_hdr);
645 		n->m_next = m->m_next;
646 		m->m_next = n;
647 		m->m_pkthdr.len += sizeof(struct ip6_hdr);
648 		oip6 = mtod(n, struct ip6_hdr *);
649 	} else {
650 		m->m_next->m_len += sizeof(struct ip6_hdr);
651 		m->m_next->m_data -= sizeof(struct ip6_hdr);
652 		m->m_pkthdr.len += sizeof(struct ip6_hdr);
653 		oip6 = mtod(m->m_next, struct ip6_hdr *);
654 	}
655 	ip6 = mtod(m, struct ip6_hdr *);
656 	bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
657 
658 	/* Fake link-local scope-class addresses */
659 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
660 		oip6->ip6_src.s6_addr16[1] = 0;
661 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
662 		oip6->ip6_dst.s6_addr16[1] = 0;
663 
664 	/* construct new IPv6 header. see RFC 2401 5.1.2.2 */
665 	/* ECN consideration. */
666 	ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
667 	if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
668 		ip6->ip6_plen = htons(plen);
669 	else {
670 		/* ip6->ip6_plen will be updated in ip6_output() */
671 	}
672 	ip6->ip6_nxt = IPPROTO_IPV6;
673 	ip6->ip6_src = sav->sah->saidx.src.sin6.sin6_addr;
674 	ip6->ip6_dst = sav->sah->saidx.dst.sin6.sin6_addr;
675 	ip6->ip6_hlim = IPV6_DEFHLIM;
676 
677 	/* XXX Should ip6_src be updated later ? */
678 
679 	return 0;
680 }
681 
682 /*
683  * IPsec output logic for IPv6, tunnel mode.
684  */
685 int
686 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
687 {
688 	struct ip6_hdr *ip6;
689 	struct ipsecrequest *isr;
690 	struct secasindex saidx;
691 	int error;
692 	struct sockaddr_in6* dst6;
693 	struct mbuf *m;
694 
695 	IPSEC_ASSERT(state != NULL, ("null state"));
696 	IPSEC_ASSERT(state->m != NULL, ("null m"));
697 	IPSEC_ASSERT(sp != NULL, ("null sp"));
698 
699 	KEYDEBUG(KEYDEBUG_IPSEC_DATA,
700 		printf("%s: applied SP\n", __func__);
701 		kdebug_secpolicy(sp));
702 
703 	m = state->m;
704 	/*
705 	 * transport mode ipsec (before the 1st tunnel mode) is already
706 	 * processed by ipsec6_output_trans().
707 	 */
708 	for (isr = sp->req; isr; isr = isr->next) {
709 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
710 			break;
711 	}
712 
713 	IPSECREQUEST_LOCK(isr);		/* insure SA contents don't change */
714 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
715 	if (isr == NULL)
716 		goto bad;
717 
718 #ifdef DEV_ENC
719 	/* pass the mbuf to enc0 for bpf processing */
720 	ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_BEFORE);
721 	/* pass the mbuf to enc0 for packet filtering */
722 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
723 		goto bad;
724 #endif
725 
726 	/*
727 	 * There may be the case that SA status will be changed when
728 	 * we are refering to one. So calling splsoftnet().
729 	 */
730 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
731 		/*
732 		 * build IPsec tunnel.
733 		 */
734 		/* XXX should be processed with other familiy */
735 		if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
736 			ipseclog((LOG_ERR, "%s: family mismatched between "
737 			    "inner and outer, spi=%u\n", __func__,
738 			    ntohl(isr->sav->spi)));
739 			ipsec6stat.ips_out_inval++;
740 			error = EAFNOSUPPORT;
741 			goto bad;
742 		}
743 
744 		m = ipsec6_splithdr(m);
745 		if (!m) {
746 			ipsec6stat.ips_out_nomem++;
747 			error = ENOMEM;
748 			goto bad;
749 		}
750 		error = ipsec6_encapsulate(m, isr->sav);
751 		if (error) {
752 			m = NULL;
753 			goto bad;
754 		}
755 		ip6 = mtod(m, struct ip6_hdr *);
756 
757 		state->ro = &isr->sav->sah->sa_route;
758 		state->dst = (struct sockaddr *)&state->ro->ro_dst;
759 		dst6 = (struct sockaddr_in6 *)state->dst;
760 		if (state->ro->ro_rt
761 		 && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
762 		  || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
763 			RTFREE(state->ro->ro_rt);
764 			state->ro->ro_rt = NULL;
765 		}
766 		if (state->ro->ro_rt == 0) {
767 			bzero(dst6, sizeof(*dst6));
768 			dst6->sin6_family = AF_INET6;
769 			dst6->sin6_len = sizeof(*dst6);
770 			dst6->sin6_addr = ip6->ip6_dst;
771 			rtalloc(state->ro);
772 		}
773 		if (state->ro->ro_rt == 0) {
774 			ip6stat.ip6s_noroute++;
775 			ipsec6stat.ips_out_noroute++;
776 			error = EHOSTUNREACH;
777 			goto bad;
778 		}
779 
780 		/* adjust state->dst if tunnel endpoint is offlink */
781 		if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
782 			state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
783 			dst6 = (struct sockaddr_in6 *)state->dst;
784 		}
785 	}
786 
787 	m = ipsec6_splithdr(m);
788 	if (!m) {
789 		ipsec6stat.ips_out_nomem++;
790 		error = ENOMEM;
791 		goto bad;
792 	}
793 	ip6 = mtod(m, struct ip6_hdr *);
794 
795 #ifdef DEV_ENC
796 	/* pass the mbuf to enc0 for bpf processing */
797 	ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_AFTER);
798 	/* pass the mbuf to enc0 for packet filtering */
799 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
800 		goto bad;
801 #endif
802 
803 	error = (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
804 		sizeof (struct ip6_hdr),
805 		offsetof(struct ip6_hdr, ip6_nxt));
806 	IPSECREQUEST_UNLOCK(isr);
807 	return error;
808 bad:
809 	if (isr)
810 		IPSECREQUEST_UNLOCK(isr);
811 	if (m)
812 		m_freem(m);
813 	state->m = NULL;
814 	return error;
815 }
816 #endif /*INET6*/
817