xref: /freebsd/sys/netipsec/ipsec_output.c (revision 2b743a9e9ddc6736208dc8ca1ce06ce64ad20a19)
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/route.h>
48 
49 #include <netinet/in.h>
50 #include <netinet/in_systm.h>
51 #include <netinet/ip.h>
52 #include <netinet/ip_var.h>
53 #include <netinet/in_var.h>
54 #include <netinet/ip_ecn.h>
55 #ifdef INET6
56 #include <netinet6/ip6_ecn.h>
57 #endif
58 
59 #include <netinet/ip6.h>
60 #ifdef INET6
61 #include <netinet6/ip6_var.h>
62 #endif
63 #include <netinet/in_pcb.h>
64 #ifdef INET6
65 #include <netinet/icmp6.h>
66 #endif
67 
68 #include <netipsec/ipsec.h>
69 #ifdef INET6
70 #include <netipsec/ipsec6.h>
71 #endif
72 #include <netipsec/ah_var.h>
73 #include <netipsec/esp_var.h>
74 #include <netipsec/ipcomp_var.h>
75 
76 #include <netipsec/xform.h>
77 
78 #include <netipsec/key.h>
79 #include <netipsec/keydb.h>
80 #include <netipsec/key_debug.h>
81 
82 #include <machine/in_cksum.h>
83 
84 int
85 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
86 {
87 	struct tdb_ident *tdbi;
88 	struct m_tag *mtag;
89 	struct secasvar *sav;
90 	struct secasindex *saidx;
91 	int error;
92 
93 	IPSEC_SPLASSERT_SOFTNET(__func__);
94 
95 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
96 	IPSEC_ASSERT(isr != NULL, ("null ISR"));
97 	sav = isr->sav;
98 	IPSEC_ASSERT(sav != NULL, ("null SA"));
99 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
100 
101 	saidx = &sav->sah->saidx;
102 	switch (saidx->dst.sa.sa_family) {
103 #ifdef INET
104 	case AF_INET:
105 		/* Fix the header length, for AH processing. */
106 		mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
107 		break;
108 #endif /* INET */
109 #ifdef INET6
110 	case AF_INET6:
111 		/* Fix the header length, for AH processing. */
112 		if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
113 			error = ENXIO;
114 			goto bad;
115 		}
116 		if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
117 			/* No jumbogram support. */
118 			error = ENXIO;	/*?*/
119 			goto bad;
120 		}
121 		mtod(m, struct ip6_hdr *)->ip6_plen =
122 			htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
123 		break;
124 #endif /* INET6 */
125 	default:
126 		DPRINTF(("%s: unknown protocol family %u\n", __func__,
127 		    saidx->dst.sa.sa_family));
128 		error = ENXIO;
129 		goto bad;
130 	}
131 
132 	/*
133 	 * Add a record of what we've done or what needs to be done to the
134 	 * packet.
135 	 */
136 	mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
137 			sizeof(struct tdb_ident), M_NOWAIT);
138 	if (mtag == NULL) {
139 		DPRINTF(("%s: could not get packet tag\n", __func__));
140 		error = ENOMEM;
141 		goto bad;
142 	}
143 
144 	tdbi = (struct tdb_ident *)(mtag + 1);
145 	tdbi->dst = saidx->dst;
146 	tdbi->proto = saidx->proto;
147 	tdbi->spi = sav->spi;
148 	m_tag_prepend(m, mtag);
149 
150 	/*
151 	 * If there's another (bundled) SA to apply, do so.
152 	 * Note that this puts a burden on the kernel stack size.
153 	 * If this is a problem we'll need to introduce a queue
154 	 * to set the packet on so we can unwind the stack before
155 	 * doing further processing.
156 	 */
157 	if (isr->next) {
158 		newipsecstat.ips_out_bundlesa++;
159 		return ipsec4_process_packet(m, isr->next, 0, 0);
160 	}
161 	key_sa_recordxfer(sav, m);		/* record data transfer */
162 
163 	/*
164 	 * We're done with IPsec processing, transmit the packet using the
165 	 * appropriate network protocol (IP or IPv6). SPD lookup will be
166 	 * performed again there.
167 	 */
168 	switch (saidx->dst.sa.sa_family) {
169 #ifdef INET
170 	struct ip *ip;
171 	case AF_INET:
172 		ip = mtod(m, struct ip *);
173 		ip->ip_len = ntohs(ip->ip_len);
174 		ip->ip_off = ntohs(ip->ip_off);
175 
176 		return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
177 #endif /* INET */
178 #ifdef INET6
179 	case AF_INET6:
180 		/*
181 		 * We don't need massage, IPv6 header fields are always in
182 		 * net endian.
183 		 */
184 		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
185 #endif /* INET6 */
186 	}
187 	panic("ipsec_process_done");
188 bad:
189 	m_freem(m);
190 	KEY_FREESAV(&sav);
191 	return (error);
192 }
193 
194 static struct ipsecrequest *
195 ipsec_nextisr(
196 	struct mbuf *m,
197 	struct ipsecrequest *isr,
198 	int af,
199 	struct secasindex *saidx,
200 	int *error
201 )
202 {
203 #define IPSEC_OSTAT(x,y,z) (isr->saidx.proto == IPPROTO_ESP ? (x)++ : \
204 			    isr->saidx.proto == IPPROTO_AH ? (y)++ : (z)++)
205 	struct secasvar *sav;
206 
207 	IPSEC_SPLASSERT_SOFTNET(__func__);
208 	IPSECREQUEST_LOCK_ASSERT(isr);
209 
210 	IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
211 		("invalid address family %u", af));
212 again:
213 	/*
214 	 * Craft SA index to search for proper SA.  Note that
215 	 * we only fillin unspecified SA peers for transport
216 	 * mode; for tunnel mode they must already be filled in.
217 	 */
218 	*saidx = isr->saidx;
219 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
220 		/* Fillin unspecified SA peers only for transport mode */
221 		if (af == AF_INET) {
222 			struct sockaddr_in *sin;
223 			struct ip *ip = mtod(m, struct ip *);
224 
225 			if (saidx->src.sa.sa_len == 0) {
226 				sin = &saidx->src.sin;
227 				sin->sin_len = sizeof(*sin);
228 				sin->sin_family = AF_INET;
229 				sin->sin_port = IPSEC_PORT_ANY;
230 				sin->sin_addr = ip->ip_src;
231 			}
232 			if (saidx->dst.sa.sa_len == 0) {
233 				sin = &saidx->dst.sin;
234 				sin->sin_len = sizeof(*sin);
235 				sin->sin_family = AF_INET;
236 				sin->sin_port = IPSEC_PORT_ANY;
237 				sin->sin_addr = ip->ip_dst;
238 			}
239 		} else {
240 			struct sockaddr_in6 *sin6;
241 			struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
242 
243 			if (saidx->src.sin6.sin6_len == 0) {
244 				sin6 = (struct sockaddr_in6 *)&saidx->src;
245 				sin6->sin6_len = sizeof(*sin6);
246 				sin6->sin6_family = AF_INET6;
247 				sin6->sin6_port = IPSEC_PORT_ANY;
248 				sin6->sin6_addr = ip6->ip6_src;
249 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
250 					/* fix scope id for comparing SPD */
251 					sin6->sin6_addr.s6_addr16[1] = 0;
252 					sin6->sin6_scope_id =
253 					    ntohs(ip6->ip6_src.s6_addr16[1]);
254 				}
255 			}
256 			if (saidx->dst.sin6.sin6_len == 0) {
257 				sin6 = (struct sockaddr_in6 *)&saidx->dst;
258 				sin6->sin6_len = sizeof(*sin6);
259 				sin6->sin6_family = AF_INET6;
260 				sin6->sin6_port = IPSEC_PORT_ANY;
261 				sin6->sin6_addr = ip6->ip6_dst;
262 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
263 					/* fix scope id for comparing SPD */
264 					sin6->sin6_addr.s6_addr16[1] = 0;
265 					sin6->sin6_scope_id =
266 					    ntohs(ip6->ip6_dst.s6_addr16[1]);
267 				}
268 			}
269 		}
270 	}
271 
272 	/*
273 	 * Lookup SA and validate it.
274 	 */
275 	*error = key_checkrequest(isr, saidx);
276 	if (*error != 0) {
277 		/*
278 		 * IPsec processing is required, but no SA found.
279 		 * I assume that key_acquire() had been called
280 		 * to get/establish the SA. Here I discard
281 		 * this packet because it is responsibility for
282 		 * upper layer to retransmit the packet.
283 		 */
284 		newipsecstat.ips_out_nosa++;
285 		goto bad;
286 	}
287 	sav = isr->sav;
288 	if (sav == NULL) {		/* XXX valid return */
289 		IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
290 			("no SA found, but required; level %u",
291 			ipsec_get_reqlevel(isr)));
292 		IPSECREQUEST_UNLOCK(isr);
293 		isr = isr->next;
294 		if (isr == NULL) {
295 			/*XXXstatistic??*/
296 			*error = EINVAL;		/*XXX*/
297 			return isr;
298 		}
299 		IPSECREQUEST_LOCK(isr);
300 		goto again;
301 	}
302 
303 	/*
304 	 * Check system global policy controls.
305 	 */
306 	if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
307 	    (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
308 	    (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
309 		DPRINTF(("%s: IPsec outbound packet dropped due"
310 			" to policy (check your sysctls)\n", __func__));
311 		IPSEC_OSTAT(espstat.esps_pdrops, ahstat.ahs_pdrops,
312 		    ipcompstat.ipcomps_pdrops);
313 		*error = EHOSTUNREACH;
314 		goto bad;
315 	}
316 
317 	/*
318 	 * Sanity check the SA contents for the caller
319 	 * before they invoke the xform output method.
320 	 */
321 	if (sav->tdb_xform == NULL) {
322 		DPRINTF(("%s: no transform for SA\n", __func__));
323 		IPSEC_OSTAT(espstat.esps_noxform, ahstat.ahs_noxform,
324 		    ipcompstat.ipcomps_noxform);
325 		*error = EHOSTUNREACH;
326 		goto bad;
327 	}
328 	return isr;
329 bad:
330 	IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
331 	IPSECREQUEST_UNLOCK(isr);
332 	return NULL;
333 #undef IPSEC_OSTAT
334 }
335 
336 #ifdef INET
337 /*
338  * IPsec output logic for IPv4.
339  */
340 int
341 ipsec4_process_packet(
342 	struct mbuf *m,
343 	struct ipsecrequest *isr,
344 	int flags,
345 	int tunalready)
346 {
347 	struct secasindex saidx;
348 	struct secasvar *sav;
349 	struct ip *ip;
350 	int error, i, off;
351 
352 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
353 	IPSEC_ASSERT(isr != NULL, ("null isr"));
354 
355 	IPSECREQUEST_LOCK(isr);		/* insure SA contents don't change */
356 
357 	isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
358 	if (isr == NULL)
359 		goto bad;
360 
361 	sav = isr->sav;
362 
363 #ifdef DEV_ENC
364 	/* pass the mbuf to enc0 for packet filtering */
365 	if ((error = ipsec_filter(&m, 2)) != 0)
366 		goto bad;
367 #endif
368 
369 	if (!tunalready) {
370 		union sockaddr_union *dst = &sav->sah->saidx.dst;
371 		int setdf;
372 
373 		/*
374 		 * Collect IP_DF state from the outer header.
375 		 */
376 		if (dst->sa.sa_family == AF_INET) {
377 			if (m->m_len < sizeof (struct ip) &&
378 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
379 				error = ENOBUFS;
380 				goto bad;
381 			}
382 			ip = mtod(m, struct ip *);
383 			/* Honor system-wide control of how to handle IP_DF */
384 			switch (ip4_ipsec_dfbit) {
385 			case 0:			/* clear in outer header */
386 			case 1:			/* set in outer header */
387 				setdf = ip4_ipsec_dfbit;
388 				break;
389 			default:		/* propagate to outer header */
390 				setdf = ntohs(ip->ip_off & IP_DF);
391 				break;
392 			}
393 		} else {
394 			ip = NULL;		/* keep compiler happy */
395 			setdf = 0;
396 		}
397 		/* Do the appropriate encapsulation, if necessary */
398 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
399 		    dst->sa.sa_family != AF_INET ||	    /* PF mismatch */
400 #if 0
401 		    (sav->flags & SADB_X_SAFLAGS_TUNNEL) || /* Tunnel requ'd */
402 		    sav->tdb_xform->xf_type == XF_IP4 ||    /* ditto */
403 #endif
404 		    (dst->sa.sa_family == AF_INET &&	    /* Proxy */
405 		     dst->sin.sin_addr.s_addr != INADDR_ANY &&
406 		     dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
407 			struct mbuf *mp;
408 
409 			/* Fix IPv4 header checksum and length */
410 			if (m->m_len < sizeof (struct ip) &&
411 			    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
412 				error = ENOBUFS;
413 				goto bad;
414 			}
415 			ip = mtod(m, struct ip *);
416 			ip->ip_len = htons(m->m_pkthdr.len);
417 			ip->ip_sum = 0;
418 #ifdef _IP_VHL
419 			if (ip->ip_vhl == IP_VHL_BORING)
420 				ip->ip_sum = in_cksum_hdr(ip);
421 			else
422 				ip->ip_sum = in_cksum(m,
423 					_IP_VHL_HL(ip->ip_vhl) << 2);
424 #else
425 			ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
426 #endif
427 
428 			/* Encapsulate the packet */
429 			error = ipip_output(m, isr, &mp, 0, 0);
430 			if (mp == NULL && !error) {
431 				/* Should never happen. */
432 				DPRINTF(("%s: ipip_output returns no mbuf and "
433 					"no error!", __func__));
434 				error = EFAULT;
435 			}
436 			if (error) {
437 				if (mp) {
438 					/* XXX: Should never happen! */
439 					m_freem(mp);
440 				}
441 				m = NULL; /* ipip_output() already freed it */
442 				goto bad;
443 			}
444 			m = mp, mp = NULL;
445 			/*
446 			 * ipip_output clears IP_DF in the new header.  If
447 			 * we need to propagate IP_DF from the outer header,
448 			 * then we have to do it here.
449 			 *
450 			 * XXX shouldn't assume what ipip_output does.
451 			 */
452 			if (dst->sa.sa_family == AF_INET && setdf) {
453 				if (m->m_len < sizeof (struct ip) &&
454 				    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
455 					error = ENOBUFS;
456 					goto bad;
457 				}
458 				ip = mtod(m, struct ip *);
459 				ip->ip_off = ntohs(ip->ip_off);
460 				ip->ip_off |= IP_DF;
461 				ip->ip_off = htons(ip->ip_off);
462 			}
463 		}
464 	}
465 
466 #ifdef DEV_ENC
467 	/* pass the mbuf to enc0 for bpf processing */
468 	ipsec_bpf(m, sav, AF_INET);
469 #endif
470 
471 	/*
472 	 * Dispatch to the appropriate IPsec transform logic.  The
473 	 * packet will be returned for transmission after crypto
474 	 * processing, etc. are completed.  For encapsulation we
475 	 * bypass this call because of the explicit call done above
476 	 * (necessary to deal with IP_DF handling for IPv4).
477 	 *
478 	 * NB: m & sav are ``passed to caller'' who's reponsible for
479 	 *     for reclaiming their resources.
480 	 */
481 	if (sav->tdb_xform->xf_type != XF_IP4) {
482 		ip = mtod(m, struct ip *);
483 		i = ip->ip_hl << 2;
484 		off = offsetof(struct ip, ip_p);
485 		error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
486 	} else {
487 		error = ipsec_process_done(m, isr);
488 	}
489 	IPSECREQUEST_UNLOCK(isr);
490 	return error;
491 bad:
492 	if (isr)
493 		IPSECREQUEST_UNLOCK(isr);
494 	if (m)
495 		m_freem(m);
496 	return error;
497 }
498 #endif
499 
500 #ifdef INET6
501 /*
502  * Chop IP6 header from the payload.
503  */
504 static struct mbuf *
505 ipsec6_splithdr(struct mbuf *m)
506 {
507 	struct mbuf *mh;
508 	struct ip6_hdr *ip6;
509 	int hlen;
510 
511 	IPSEC_ASSERT(m->m_len >= sizeof (struct ip6_hdr),
512 		("first mbuf too short, len %u", m->m_len));
513 	ip6 = mtod(m, struct ip6_hdr *);
514 	hlen = sizeof(struct ip6_hdr);
515 	if (m->m_len > hlen) {
516 		MGETHDR(mh, M_DONTWAIT, MT_DATA);
517 		if (!mh) {
518 			m_freem(m);
519 			return NULL;
520 		}
521 		M_MOVE_PKTHDR(mh, m);
522 		MH_ALIGN(mh, hlen);
523 		m->m_len -= hlen;
524 		m->m_data += hlen;
525 		mh->m_next = m;
526 		m = mh;
527 		m->m_len = hlen;
528 		bcopy((caddr_t)ip6, mtod(m, caddr_t), hlen);
529 	} else if (m->m_len < hlen) {
530 		m = m_pullup(m, hlen);
531 		if (!m)
532 			return NULL;
533 	}
534 	return m;
535 }
536 
537 /*
538  * IPsec output logic for IPv6, transport mode.
539  */
540 int
541 ipsec6_output_trans(
542 	struct ipsec_output_state *state,
543 	u_char *nexthdrp,
544 	struct mbuf *mprev,
545 	struct secpolicy *sp,
546 	int flags,
547 	int *tun)
548 {
549 	struct ipsecrequest *isr;
550 	struct secasindex saidx;
551 	int error = 0;
552 	struct mbuf *m;
553 
554 	IPSEC_ASSERT(state != NULL, ("null state"));
555 	IPSEC_ASSERT(state->m != NULL, ("null m"));
556 	IPSEC_ASSERT(nexthdrp != NULL, ("null nexthdrp"));
557 	IPSEC_ASSERT(mprev != NULL, ("null mprev"));
558 	IPSEC_ASSERT(sp != NULL, ("null sp"));
559 	IPSEC_ASSERT(tun != NULL, ("null tun"));
560 
561 	KEYDEBUG(KEYDEBUG_IPSEC_DATA,
562 		printf("%s: applyed SP\n", __func__);
563 		kdebug_secpolicy(sp));
564 
565 	isr = sp->req;
566 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
567 		/* the rest will be handled by ipsec6_output_tunnel() */
568 		*tun = 1;		/* need tunnel-mode processing */
569 		return 0;
570 	}
571 
572 	*tun = 0;
573 	m = state->m;
574 
575 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
576 	if (isr == NULL) {
577 #ifdef notdef
578 		/* XXX should notification be done for all errors ? */
579 		/*
580 		 * Notify the fact that the packet is discarded
581 		 * to ourselves. I believe this is better than
582 		 * just silently discarding. (jinmei@kame.net)
583 		 * XXX: should we restrict the error to TCP packets?
584 		 * XXX: should we directly notify sockets via
585 		 *      pfctlinputs?
586 		 */
587 		icmp6_error(m, ICMP6_DST_UNREACH,
588 			    ICMP6_DST_UNREACH_ADMIN, 0);
589 		m = NULL;	/* NB: icmp6_error frees mbuf */
590 #endif
591 		goto bad;
592 	}
593 
594 	return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
595 		sizeof (struct ip6_hdr),
596 		offsetof(struct ip6_hdr, ip6_nxt));
597 bad:
598 	if (m)
599 		m_freem(m);
600 	state->m = NULL;
601 	return error;
602 }
603 
604 static int
605 ipsec6_encapsulate(struct mbuf *m, struct secasvar *sav)
606 {
607 	struct ip6_hdr *oip6;
608 	struct ip6_hdr *ip6;
609 	size_t plen;
610 
611 	/* can't tunnel between different AFs */
612 	if (sav->sah->saidx.src.sa.sa_family != AF_INET6 ||
613 	    sav->sah->saidx.dst.sa.sa_family != AF_INET6) {
614 		m_freem(m);
615 		return EINVAL;
616 	}
617 	IPSEC_ASSERT(m->m_len != sizeof (struct ip6_hdr),
618 		("mbuf wrong size; len %u", m->m_len));
619 
620 
621 	/*
622 	 * grow the mbuf to accomodate the new IPv6 header.
623 	 */
624 	plen = m->m_pkthdr.len;
625 	if (M_LEADINGSPACE(m->m_next) < sizeof(struct ip6_hdr)) {
626 		struct mbuf *n;
627 		MGET(n, M_DONTWAIT, MT_DATA);
628 		if (!n) {
629 			m_freem(m);
630 			return ENOBUFS;
631 		}
632 		n->m_len = sizeof(struct ip6_hdr);
633 		n->m_next = m->m_next;
634 		m->m_next = n;
635 		m->m_pkthdr.len += sizeof(struct ip6_hdr);
636 		oip6 = mtod(n, struct ip6_hdr *);
637 	} else {
638 		m->m_next->m_len += sizeof(struct ip6_hdr);
639 		m->m_next->m_data -= sizeof(struct ip6_hdr);
640 		m->m_pkthdr.len += sizeof(struct ip6_hdr);
641 		oip6 = mtod(m->m_next, struct ip6_hdr *);
642 	}
643 	ip6 = mtod(m, struct ip6_hdr *);
644 	bcopy((caddr_t)ip6, (caddr_t)oip6, sizeof(struct ip6_hdr));
645 
646 	/* Fake link-local scope-class addresses */
647 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_src))
648 		oip6->ip6_src.s6_addr16[1] = 0;
649 	if (IN6_IS_SCOPE_LINKLOCAL(&oip6->ip6_dst))
650 		oip6->ip6_dst.s6_addr16[1] = 0;
651 
652 	/* construct new IPv6 header. see RFC 2401 5.1.2.2 */
653 	/* ECN consideration. */
654 	ip6_ecn_ingress(ip6_ipsec_ecn, &ip6->ip6_flow, &oip6->ip6_flow);
655 	if (plen < IPV6_MAXPACKET - sizeof(struct ip6_hdr))
656 		ip6->ip6_plen = htons(plen);
657 	else {
658 		/* ip6->ip6_plen will be updated in ip6_output() */
659 	}
660 	ip6->ip6_nxt = IPPROTO_IPV6;
661 	sav->sah->saidx.src.sin6.sin6_addr = ip6->ip6_src;
662 	sav->sah->saidx.dst.sin6.sin6_addr = ip6->ip6_dst;
663 	ip6->ip6_hlim = IPV6_DEFHLIM;
664 
665 	/* XXX Should ip6_src be updated later ? */
666 
667 	return 0;
668 }
669 
670 /*
671  * IPsec output logic for IPv6, tunnel mode.
672  */
673 int
674 ipsec6_output_tunnel(struct ipsec_output_state *state, struct secpolicy *sp, int flags)
675 {
676 	struct ip6_hdr *ip6;
677 	struct ipsecrequest *isr;
678 	struct secasindex saidx;
679 	int error;
680 	struct sockaddr_in6* dst6;
681 	struct mbuf *m;
682 
683 	IPSEC_ASSERT(state != NULL, ("null state"));
684 	IPSEC_ASSERT(state->m != NULL, ("null m"));
685 	IPSEC_ASSERT(sp != NULL, ("null sp"));
686 
687 	KEYDEBUG(KEYDEBUG_IPSEC_DATA,
688 		printf("%s: applyed SP\n", __func__);
689 		kdebug_secpolicy(sp));
690 
691 	m = state->m;
692 	/*
693 	 * transport mode ipsec (before the 1st tunnel mode) is already
694 	 * processed by ipsec6_output_trans().
695 	 */
696 	for (isr = sp->req; isr; isr = isr->next) {
697 		if (isr->saidx.mode == IPSEC_MODE_TUNNEL)
698 			break;
699 	}
700 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
701 	if (isr == NULL)
702 		goto bad;
703 
704 	/*
705 	 * There may be the case that SA status will be changed when
706 	 * we are refering to one. So calling splsoftnet().
707 	 */
708 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL) {
709 		/*
710 		 * build IPsec tunnel.
711 		 */
712 		/* XXX should be processed with other familiy */
713 		if (isr->sav->sah->saidx.src.sa.sa_family != AF_INET6) {
714 			ipseclog((LOG_ERR, "%s: family mismatched between "
715 			    "inner and outer, spi=%u\n", __func__,
716 			    ntohl(isr->sav->spi)));
717 			newipsecstat.ips_out_inval++;
718 			error = EAFNOSUPPORT;
719 			goto bad;
720 		}
721 
722 		m = ipsec6_splithdr(m);
723 		if (!m) {
724 			newipsecstat.ips_out_nomem++;
725 			error = ENOMEM;
726 			goto bad;
727 		}
728 		error = ipsec6_encapsulate(m, isr->sav);
729 		if (error) {
730 			m = NULL;
731 			goto bad;
732 		}
733 		ip6 = mtod(m, struct ip6_hdr *);
734 
735 		state->ro = &isr->sav->sah->sa_route;
736 		state->dst = (struct sockaddr *)&state->ro->ro_dst;
737 		dst6 = (struct sockaddr_in6 *)state->dst;
738 		if (state->ro->ro_rt
739 		 && ((state->ro->ro_rt->rt_flags & RTF_UP) == 0
740 		  || !IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr, &ip6->ip6_dst))) {
741 			RTFREE(state->ro->ro_rt);
742 			state->ro->ro_rt = NULL;
743 		}
744 		if (state->ro->ro_rt == 0) {
745 			bzero(dst6, sizeof(*dst6));
746 			dst6->sin6_family = AF_INET6;
747 			dst6->sin6_len = sizeof(*dst6);
748 			dst6->sin6_addr = ip6->ip6_dst;
749 			rtalloc(state->ro);
750 		}
751 		if (state->ro->ro_rt == 0) {
752 			ip6stat.ip6s_noroute++;
753 			newipsecstat.ips_out_noroute++;
754 			error = EHOSTUNREACH;
755 			goto bad;
756 		}
757 
758 		/* adjust state->dst if tunnel endpoint is offlink */
759 		if (state->ro->ro_rt->rt_flags & RTF_GATEWAY) {
760 			state->dst = (struct sockaddr *)state->ro->ro_rt->rt_gateway;
761 			dst6 = (struct sockaddr_in6 *)state->dst;
762 		}
763 	}
764 
765 	m = ipsec6_splithdr(m);
766 	if (!m) {
767 		newipsecstat.ips_out_nomem++;
768 		error = ENOMEM;
769 		goto bad;
770 	}
771 	ip6 = mtod(m, struct ip6_hdr *);
772 	return (*isr->sav->tdb_xform->xf_output)(m, isr, NULL,
773 		sizeof (struct ip6_hdr),
774 		offsetof(struct ip6_hdr, ip6_nxt));
775 bad:
776 	if (m)
777 		m_freem(m);
778 	state->m = NULL;
779 	return error;
780 }
781 #endif /*INET6*/
782