xref: /freebsd/sys/netipsec/ipsec_output.c (revision 3df058ffaf72b8715c9a5a6a4cbaf1eac1910e43)
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/if_var.h>
48 #include <net/pfil.h>
49 #include <net/vnet.h>
50 
51 #include <netinet/in.h>
52 #include <netinet/in_systm.h>
53 #include <netinet/ip.h>
54 #include <netinet/ip_var.h>
55 #include <netinet/in_var.h>
56 #include <netinet/ip_ecn.h>
57 #ifdef INET6
58 #include <netinet6/ip6_ecn.h>
59 #endif
60 
61 #include <netinet/ip6.h>
62 #ifdef INET6
63 #include <netinet6/ip6_var.h>
64 #include <netinet6/scope6_var.h>
65 #endif
66 #include <netinet/in_pcb.h>
67 #ifdef INET6
68 #include <netinet/icmp6.h>
69 #endif
70 
71 #include <netipsec/ipsec.h>
72 #ifdef INET6
73 #include <netipsec/ipsec6.h>
74 #endif
75 #include <netipsec/ah_var.h>
76 #include <netipsec/esp_var.h>
77 #include <netipsec/ipcomp_var.h>
78 
79 #include <netipsec/xform.h>
80 
81 #include <netipsec/key.h>
82 #include <netipsec/keydb.h>
83 #include <netipsec/key_debug.h>
84 
85 #include <machine/in_cksum.h>
86 
87 #ifdef IPSEC_NAT_T
88 #include <netinet/udp.h>
89 #endif
90 
91 #ifdef DEV_ENC
92 #include <net/if_enc.h>
93 #endif
94 
95 
96 int
97 ipsec_process_done(struct mbuf *m, struct ipsecrequest *isr)
98 {
99 	struct tdb_ident *tdbi;
100 	struct m_tag *mtag;
101 	struct secasvar *sav;
102 	struct secasindex *saidx;
103 	int error;
104 
105 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
106 	IPSEC_ASSERT(isr != NULL, ("null ISR"));
107 	IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
108 	sav = isr->sav;
109 	IPSEC_ASSERT(sav != NULL, ("null SA"));
110 	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
111 
112 	saidx = &sav->sah->saidx;
113 	switch (saidx->dst.sa.sa_family) {
114 #ifdef INET
115 	case AF_INET:
116 		/* Fix the header length, for AH processing. */
117 		mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
118 		break;
119 #endif /* INET */
120 #ifdef INET6
121 	case AF_INET6:
122 		/* Fix the header length, for AH processing. */
123 		if (m->m_pkthdr.len < sizeof (struct ip6_hdr)) {
124 			error = ENXIO;
125 			goto bad;
126 		}
127 		if (m->m_pkthdr.len - sizeof (struct ip6_hdr) > IPV6_MAXPACKET) {
128 			/* No jumbogram support. */
129 			error = ENXIO;	/*?*/
130 			goto bad;
131 		}
132 		mtod(m, struct ip6_hdr *)->ip6_plen =
133 			htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
134 		break;
135 #endif /* INET6 */
136 	default:
137 		DPRINTF(("%s: unknown protocol family %u\n", __func__,
138 		    saidx->dst.sa.sa_family));
139 		error = ENXIO;
140 		goto bad;
141 	}
142 
143 	/*
144 	 * Add a record of what we've done or what needs to be done to the
145 	 * packet.
146 	 */
147 	mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE,
148 			sizeof(struct tdb_ident), M_NOWAIT);
149 	if (mtag == NULL) {
150 		DPRINTF(("%s: could not get packet tag\n", __func__));
151 		error = ENOMEM;
152 		goto bad;
153 	}
154 
155 	tdbi = (struct tdb_ident *)(mtag + 1);
156 	tdbi->dst = saidx->dst;
157 	tdbi->proto = saidx->proto;
158 	tdbi->spi = sav->spi;
159 	m_tag_prepend(m, mtag);
160 
161 	key_sa_recordxfer(sav, m);		/* record data transfer */
162 
163 	/*
164 	 * If there's another (bundled) SA to apply, do so.
165 	 * Note that this puts a burden on the kernel stack size.
166 	 * If this is a problem we'll need to introduce a queue
167 	 * to set the packet on so we can unwind the stack before
168 	 * doing further processing.
169 	 *
170 	 * If ipsec[46]_process_packet() will successfully queue
171 	 * the request, we need to take additional reference to SP,
172 	 * because xform callback will release reference.
173 	 */
174 	if (isr->next) {
175 		/* XXX-BZ currently only support same AF bundles. */
176 		switch (saidx->dst.sa.sa_family) {
177 #ifdef INET
178 		case AF_INET:
179 			IPSECSTAT_INC(ips_out_bundlesa);
180 			key_addref(isr->sp);
181 			error = ipsec4_process_packet(m, isr->next);
182 			if (error != 0)
183 				KEY_FREESP(&isr->sp);
184 			return (error);
185 			/* NOTREACHED */
186 #endif
187 #ifdef notyet
188 #ifdef INET6
189 		case AF_INET6:
190 			/* XXX */
191 			IPSEC6STAT_INC(ips_out_bundlesa);
192 			key_addref(isr->sp);
193 			error = ipsec6_process_packet(m, isr->next);
194 			if (error != 0)
195 				KEY_FREESP(&isr->sp);
196 			return (error);
197 			/* NOTREACHED */
198 #endif /* INET6 */
199 #endif
200 		default:
201 			DPRINTF(("%s: unknown protocol family %u\n", __func__,
202 			    saidx->dst.sa.sa_family));
203 			error = ENXIO;
204 			goto bad;
205 		}
206 	}
207 
208 	/*
209 	 * We're done with IPsec processing, transmit the packet using the
210 	 * appropriate network protocol (IP or IPv6).
211 	 */
212 	switch (saidx->dst.sa.sa_family) {
213 #ifdef INET
214 	case AF_INET:
215 #ifdef IPSEC_NAT_T
216 		/*
217 		 * If NAT-T is enabled, now that all IPsec processing is done
218 		 * insert UDP encapsulation header after IP header.
219 		 */
220 		if (sav->natt_type) {
221 			struct ip *ip = mtod(m, struct ip *);
222 			const int hlen = (ip->ip_hl << 2);
223 			int size, off;
224 			struct mbuf *mi;
225 			struct udphdr *udp;
226 
227 			size = sizeof(struct udphdr);
228 			if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
229 				/*
230 				 * draft-ietf-ipsec-nat-t-ike-0[01].txt and
231 				 * draft-ietf-ipsec-udp-encaps-(00/)01.txt,
232 				 * ignoring possible AH mode
233 				 * non-IKE marker + non-ESP marker
234 				 * from draft-ietf-ipsec-udp-encaps-00.txt.
235 				 */
236 				size += sizeof(u_int64_t);
237 			}
238 			mi = m_makespace(m, hlen, size, &off);
239 			if (mi == NULL) {
240 				DPRINTF(("%s: m_makespace for udphdr failed\n",
241 				    __func__));
242 				error = ENOBUFS;
243 				goto bad;
244 			}
245 
246 			udp = (struct udphdr *)(mtod(mi, caddr_t) + off);
247 			if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
248 				udp->uh_sport = htons(UDP_ENCAP_ESPINUDP_PORT);
249 			else
250 				udp->uh_sport =
251 					KEY_PORTFROMSADDR(&sav->sah->saidx.src);
252 			udp->uh_dport = KEY_PORTFROMSADDR(&sav->sah->saidx.dst);
253 			udp->uh_sum = 0;
254 			udp->uh_ulen = htons(m->m_pkthdr.len - hlen);
255 			ip->ip_len = htons(m->m_pkthdr.len);
256 			ip->ip_p = IPPROTO_UDP;
257 
258 			if (sav->natt_type == UDP_ENCAP_ESPINUDP_NON_IKE)
259 				*(u_int64_t *)(udp + 1) = 0;
260 		}
261 #endif /* IPSEC_NAT_T */
262 
263 		return ip_output(m, NULL, NULL, IP_RAWOUTPUT, NULL, NULL);
264 #endif /* INET */
265 #ifdef INET6
266 	case AF_INET6:
267 		/*
268 		 * We don't need massage, IPv6 header fields are always in
269 		 * net endian.
270 		 */
271 		return ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
272 #endif /* INET6 */
273 	}
274 	panic("ipsec_process_done");
275 bad:
276 	m_freem(m);
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(name)	do {		\
290 	if (isr->saidx.proto == IPPROTO_ESP)	\
291 		ESPSTAT_INC(esps_##name);	\
292 	else if (isr->saidx.proto == IPPROTO_AH)\
293 		AHSTAT_INC(ahs_##name);		\
294 	else					\
295 		IPCOMPSTAT_INC(ipcomps_##name);	\
296 } while (0)
297 	struct secasvar *sav;
298 
299 	IPSECREQUEST_LOCK_ASSERT(isr);
300 
301 	IPSEC_ASSERT(af == AF_INET || af == AF_INET6,
302 		("invalid address family %u", af));
303 again:
304 	/*
305 	 * Craft SA index to search for proper SA.  Note that
306 	 * we only fillin unspecified SA peers for transport
307 	 * mode; for tunnel mode they must already be filled in.
308 	 */
309 	*saidx = isr->saidx;
310 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
311 		/* Fillin unspecified SA peers only for transport mode */
312 		if (af == AF_INET) {
313 			struct sockaddr_in *sin;
314 			struct ip *ip = mtod(m, struct ip *);
315 
316 			if (saidx->src.sa.sa_len == 0) {
317 				sin = &saidx->src.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_src;
322 			}
323 			if (saidx->dst.sa.sa_len == 0) {
324 				sin = &saidx->dst.sin;
325 				sin->sin_len = sizeof(*sin);
326 				sin->sin_family = AF_INET;
327 				sin->sin_port = IPSEC_PORT_ANY;
328 				sin->sin_addr = ip->ip_dst;
329 			}
330 		} else {
331 			struct sockaddr_in6 *sin6;
332 			struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
333 
334 			if (saidx->src.sin6.sin6_len == 0) {
335 				sin6 = (struct sockaddr_in6 *)&saidx->src;
336 				sin6->sin6_len = sizeof(*sin6);
337 				sin6->sin6_family = AF_INET6;
338 				sin6->sin6_port = IPSEC_PORT_ANY;
339 				sin6->sin6_addr = ip6->ip6_src;
340 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
341 					/* fix scope id for comparing SPD */
342 					sin6->sin6_addr.s6_addr16[1] = 0;
343 					sin6->sin6_scope_id =
344 					    ntohs(ip6->ip6_src.s6_addr16[1]);
345 				}
346 			}
347 			if (saidx->dst.sin6.sin6_len == 0) {
348 				sin6 = (struct sockaddr_in6 *)&saidx->dst;
349 				sin6->sin6_len = sizeof(*sin6);
350 				sin6->sin6_family = AF_INET6;
351 				sin6->sin6_port = IPSEC_PORT_ANY;
352 				sin6->sin6_addr = ip6->ip6_dst;
353 				if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
354 					/* fix scope id for comparing SPD */
355 					sin6->sin6_addr.s6_addr16[1] = 0;
356 					sin6->sin6_scope_id =
357 					    ntohs(ip6->ip6_dst.s6_addr16[1]);
358 				}
359 			}
360 		}
361 	}
362 
363 	/*
364 	 * Lookup SA and validate it.
365 	 */
366 	*error = key_checkrequest(isr, saidx);
367 	if (*error != 0) {
368 		/*
369 		 * IPsec processing is required, but no SA found.
370 		 * I assume that key_acquire() had been called
371 		 * to get/establish the SA. Here I discard
372 		 * this packet because it is responsibility for
373 		 * upper layer to retransmit the packet.
374 		 */
375 		switch(af) {
376 		case AF_INET:
377 			IPSECSTAT_INC(ips_out_nosa);
378 			break;
379 #ifdef INET6
380 		case AF_INET6:
381 			IPSEC6STAT_INC(ips_out_nosa);
382 			break;
383 #endif
384 		}
385 		goto bad;
386 	}
387 	sav = isr->sav;
388 	if (sav == NULL) {
389 		IPSEC_ASSERT(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
390 			("no SA found, but required; level %u",
391 			ipsec_get_reqlevel(isr)));
392 		IPSECREQUEST_UNLOCK(isr);
393 		isr = isr->next;
394 		/*
395 		 * If isr is NULL, we found a 'use' policy w/o SA.
396 		 * Return w/o error and w/o isr so we can drop out
397 		 * and continue w/o IPsec processing.
398 		 */
399 		if (isr == NULL)
400 			return isr;
401 		IPSECREQUEST_LOCK(isr);
402 		goto again;
403 	}
404 
405 	/*
406 	 * Check system global policy controls.
407 	 */
408 	if ((isr->saidx.proto == IPPROTO_ESP && !V_esp_enable) ||
409 	    (isr->saidx.proto == IPPROTO_AH && !V_ah_enable) ||
410 	    (isr->saidx.proto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
411 		DPRINTF(("%s: IPsec outbound packet dropped due"
412 			" to policy (check your sysctls)\n", __func__));
413 		IPSEC_OSTAT(pdrops);
414 		*error = EHOSTUNREACH;
415 		goto bad;
416 	}
417 
418 	/*
419 	 * Sanity check the SA contents for the caller
420 	 * before they invoke the xform output method.
421 	 */
422 	if (sav->tdb_xform == NULL) {
423 		DPRINTF(("%s: no transform for SA\n", __func__));
424 		IPSEC_OSTAT(noxform);
425 		*error = EHOSTUNREACH;
426 		goto bad;
427 	}
428 	return isr;
429 bad:
430 	IPSEC_ASSERT(*error != 0, ("error return w/ no error code"));
431 	IPSECREQUEST_UNLOCK(isr);
432 	return NULL;
433 #undef IPSEC_OSTAT
434 }
435 
436 static int
437 ipsec_encap(struct mbuf **mp, struct secasindex *saidx)
438 {
439 #ifdef INET6
440 	struct ip6_hdr *ip6;
441 #endif
442 	struct ip *ip;
443 	int setdf;
444 	uint8_t itos, proto;
445 
446 	ip = mtod(*mp, struct ip *);
447 	switch (ip->ip_v) {
448 #ifdef INET
449 	case IPVERSION:
450 		proto = IPPROTO_IPIP;
451 		/*
452 		 * Collect IP_DF state from the inner header
453 		 * and honor system-wide control of how to handle it.
454 		 */
455 		switch (V_ip4_ipsec_dfbit) {
456 		case 0:	/* clear in outer header */
457 		case 1:	/* set in outer header */
458 			setdf = V_ip4_ipsec_dfbit;
459 			break;
460 		default:/* propagate to outer header */
461 			setdf = (ip->ip_off & ntohs(IP_DF)) != 0;
462 		}
463 		itos = ip->ip_tos;
464 		break;
465 #endif
466 #ifdef INET6
467 	case (IPV6_VERSION >> 4):
468 		proto = IPPROTO_IPV6;
469 		ip6 = mtod(*mp, struct ip6_hdr *);
470 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
471 		setdf = V_ip4_ipsec_dfbit ? 1: 0;
472 		/* scoped address handling */
473 		in6_clearscope(&ip6->ip6_src);
474 		in6_clearscope(&ip6->ip6_dst);
475 		break;
476 #endif
477 	default:
478 		return (EAFNOSUPPORT);
479 	}
480 	switch (saidx->dst.sa.sa_family) {
481 #ifdef INET
482 	case AF_INET:
483 		if (saidx->src.sa.sa_family != AF_INET ||
484 		    saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
485 		    saidx->dst.sin.sin_addr.s_addr == INADDR_ANY)
486 			return (EINVAL);
487 		M_PREPEND(*mp, sizeof(struct ip), M_NOWAIT);
488 		if (*mp == NULL)
489 			return (ENOBUFS);
490 		ip = mtod(*mp, struct ip *);
491 		ip->ip_v = IPVERSION;
492 		ip->ip_hl = sizeof(struct ip) >> 2;
493 		ip->ip_p = proto;
494 		ip->ip_len = htons((*mp)->m_pkthdr.len);
495 		ip->ip_ttl = V_ip_defttl;
496 		ip->ip_sum = 0;
497 		ip->ip_off = setdf ? htons(IP_DF): 0;
498 		ip->ip_src = saidx->src.sin.sin_addr;
499 		ip->ip_dst = saidx->dst.sin.sin_addr;
500 		ip_ecn_ingress(V_ip4_ipsec_ecn, &ip->ip_tos, &itos);
501 		ip_fillid(ip);
502 		break;
503 #endif /* INET */
504 #ifdef INET6
505 	case AF_INET6:
506 		if (saidx->src.sa.sa_family != AF_INET6 ||
507 		    IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr) ||
508 		    IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr))
509 			return (EINVAL);
510 		M_PREPEND(*mp, sizeof(struct ip6_hdr), M_NOWAIT);
511 		if (*mp == NULL)
512 			return (ENOBUFS);
513 		ip6 = mtod(*mp, struct ip6_hdr *);
514 		ip6->ip6_flow = 0;
515 		ip6->ip6_vfc = IPV6_VERSION;
516 		ip6->ip6_hlim = V_ip6_defhlim;
517 		ip6->ip6_nxt = proto;
518 		ip6->ip6_dst = saidx->dst.sin6.sin6_addr;
519 		/* For link-local address embed scope zone id */
520 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
521 			ip6->ip6_dst.s6_addr16[1] =
522 			    htons(saidx->dst.sin6.sin6_scope_id & 0xffff);
523 		ip6->ip6_src = saidx->src.sin6.sin6_addr;
524 		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
525 			ip6->ip6_src.s6_addr16[1] =
526 			    htons(saidx->src.sin6.sin6_scope_id & 0xffff);
527 		ip6->ip6_plen = htons((*mp)->m_pkthdr.len - sizeof(*ip6));
528 		ip_ecn_ingress(V_ip6_ipsec_ecn, &proto, &itos);
529 		ip6->ip6_flow |= htonl((uint32_t)proto << 20);
530 		break;
531 #endif /* INET6 */
532 	default:
533 		return (EAFNOSUPPORT);
534 	}
535 	return (0);
536 }
537 
538 #ifdef INET
539 /*
540  * IPsec output logic for IPv4.
541  */
542 int
543 ipsec4_process_packet(struct mbuf *m, struct ipsecrequest *isr)
544 {
545 	char sbuf[INET6_ADDRSTRLEN], dbuf[INET6_ADDRSTRLEN];
546 	union sockaddr_union *dst;
547 	struct secasindex saidx;
548 	struct secasvar *sav;
549 	struct ip *ip;
550 	int error, i, off;
551 
552 	IPSEC_ASSERT(m != NULL, ("null mbuf"));
553 	IPSEC_ASSERT(isr != NULL, ("null isr"));
554 
555 	IPSECREQUEST_LOCK(isr);		/* insure SA contents don't change */
556 
557 	isr = ipsec_nextisr(m, isr, AF_INET, &saidx, &error);
558 	if (isr == NULL) {
559 		if (error != 0)
560 			goto bad;
561 		return EJUSTRETURN;
562 	}
563 
564 	sav = isr->sav;
565 	if (m->m_len < sizeof(struct ip) &&
566 	    (m = m_pullup(m, sizeof (struct ip))) == NULL) {
567 		error = ENOBUFS;
568 		goto bad;
569 	}
570 	ip = mtod(m, struct ip *);
571 	dst = &sav->sah->saidx.dst;
572 #ifdef DEV_ENC
573 	if_inc_counter(encif, IFCOUNTER_OPACKETS, 1);
574 	if_inc_counter(encif, IFCOUNTER_OBYTES, m->m_pkthdr.len);
575 
576 	/* pass the mbuf to enc0 for bpf processing */
577 	ipsec_bpf(m, sav, AF_INET, ENC_OUT|ENC_BEFORE);
578 	/* pass the mbuf to enc0 for packet filtering */
579 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
580 		goto bad;
581 	ip = mtod(m, struct ip *);
582 #endif
583 	/* Do the appropriate encapsulation, if necessary */
584 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
585 	    dst->sa.sa_family != AF_INET ||	    /* PF mismatch */
586 	    (dst->sa.sa_family == AF_INET &&	    /* Proxy */
587 	     dst->sin.sin_addr.s_addr != INADDR_ANY &&
588 	     dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
589 		/* Fix IPv4 header checksum and length */
590 		ip->ip_len = htons(m->m_pkthdr.len);
591 		ip->ip_sum = 0;
592 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
593 		error = ipsec_encap(&m, &sav->sah->saidx);
594 		if (error != 0) {
595 			DPRINTF(("%s: encapsulation for SA %s->%s "
596 			    "SPI 0x%08x failed with error %d\n", __func__,
597 			    ipsec_address(&sav->sah->saidx.src, sbuf,
598 				sizeof(sbuf)),
599 			    ipsec_address(&sav->sah->saidx.dst, dbuf,
600 				sizeof(dbuf)), ntohl(sav->spi), error));
601 			goto bad;
602 		}
603 	}
604 #ifdef DEV_ENC
605 	/* pass the mbuf to enc0 for bpf processing */
606 	ipsec_bpf(m, sav, sav->sah->saidx.dst.sa.sa_family, ENC_OUT|ENC_AFTER);
607 	/* pass the mbuf to enc0 for packet filtering */
608 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
609 		goto bad;
610 #endif
611 
612 	/*
613 	 * Dispatch to the appropriate IPsec transform logic.  The
614 	 * packet will be returned for transmission after crypto
615 	 * processing, etc. are completed.
616 	 *
617 	 * NB: m & sav are ``passed to caller'' who's reponsible for
618 	 *     for reclaiming their resources.
619 	 */
620 	switch(dst->sa.sa_family) {
621 	case AF_INET:
622 		ip = mtod(m, struct ip *);
623 		i = ip->ip_hl << 2;
624 		off = offsetof(struct ip, ip_p);
625 		break;
626 #ifdef INET6
627 	case AF_INET6:
628 		i = sizeof(struct ip6_hdr);
629 		off = offsetof(struct ip6_hdr, ip6_nxt);
630 		break;
631 #endif /* INET6 */
632 	default:
633 		DPRINTF(("%s: unsupported protocol family %u\n",
634 		    __func__, dst->sa.sa_family));
635 		error = EPFNOSUPPORT;
636 		IPSECSTAT_INC(ips_out_inval);
637 		goto bad;
638 	}
639 	error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
640 	IPSECREQUEST_UNLOCK(isr);
641 	return (error);
642 bad:
643 	if (isr)
644 		IPSECREQUEST_UNLOCK(isr);
645 	if (m)
646 		m_freem(m);
647 	return error;
648 }
649 #endif
650 
651 
652 #ifdef INET6
653 static int
654 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa, const struct in6_addr *ia)
655 {
656 	struct in6_addr ia2;
657 
658 	memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
659 	if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr))
660 		ia2.s6_addr16[1] = htons(sa->sin6_scope_id);
661 
662 	return IN6_ARE_ADDR_EQUAL(ia, &ia2);
663 }
664 
665 /*
666  * IPsec output logic for IPv6.
667  */
668 int
669 ipsec6_process_packet(struct mbuf *m, struct ipsecrequest *isr)
670 {
671 	char sbuf[INET6_ADDRSTRLEN], dbuf[INET6_ADDRSTRLEN];
672 	struct secasindex saidx;
673 	struct secasvar *sav;
674 	struct ip6_hdr *ip6;
675 	int error, i, off;
676 	union sockaddr_union *dst;
677 
678 	IPSEC_ASSERT(m != NULL, ("ipsec6_process_packet: null mbuf"));
679 	IPSEC_ASSERT(isr != NULL, ("ipsec6_process_packet: null isr"));
680 
681 	IPSECREQUEST_LOCK(isr);		/* insure SA contents don't change */
682 
683 	isr = ipsec_nextisr(m, isr, AF_INET6, &saidx, &error);
684 	if (isr == NULL) {
685 		if (error != 0)
686 			goto bad;
687 		return EJUSTRETURN;
688 	}
689 	sav = isr->sav;
690 	dst = &sav->sah->saidx.dst;
691 
692 	ip6 = mtod(m, struct ip6_hdr *);
693 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
694 #ifdef DEV_ENC
695 	if_inc_counter(encif, IFCOUNTER_OPACKETS, 1);
696 	if_inc_counter(encif, IFCOUNTER_OBYTES, m->m_pkthdr.len);
697 
698 	/* pass the mbuf to enc0 for bpf processing */
699 	ipsec_bpf(m, isr->sav, AF_INET6, ENC_OUT|ENC_BEFORE);
700 	/* pass the mbuf to enc0 for packet filtering */
701 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_BEFORE)) != 0)
702 		goto bad;
703 	ip6 = mtod(m, struct ip6_hdr *);
704 #endif /* DEV_ENC */
705 
706 	/* Do the appropriate encapsulation, if necessary */
707 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
708 	    dst->sa.sa_family != AF_INET6 ||        /* PF mismatch */
709 	    ((dst->sa.sa_family == AF_INET6) &&
710 	     (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
711 	     (!in6_sa_equal_addrwithscope(&dst->sin6,
712 				  &ip6->ip6_dst)))) {
713 		if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
714 			/* No jumbogram support. */
715 			error = ENXIO;   /*XXX*/
716 			goto bad;
717 		}
718 		error = ipsec_encap(&m, &sav->sah->saidx);
719 		if (error != 0) {
720 			DPRINTF(("%s: encapsulation for SA %s->%s "
721 			    "SPI 0x%08x failed with error %d\n", __func__,
722 			    ipsec_address(&sav->sah->saidx.src, sbuf,
723 				sizeof(sbuf)),
724 			    ipsec_address(&sav->sah->saidx.dst, dbuf,
725 				sizeof(dbuf)), ntohl(sav->spi), error));
726 			goto bad;
727 		}
728 	}
729 
730 #ifdef DEV_ENC
731 	ipsec_bpf(m, isr->sav, dst->sa.sa_family, ENC_OUT|ENC_AFTER);
732 	/* pass the mbuf to enc0 for packet filtering */
733 	if ((error = ipsec_filter(&m, PFIL_OUT, ENC_OUT|ENC_AFTER)) != 0)
734 		goto bad;
735 #endif /* DEV_ENC */
736 
737 	switch(dst->sa.sa_family) {
738 #ifdef INET
739 	case AF_INET:
740 		{
741 		struct ip *ip;
742 		ip = mtod(m, struct ip *);
743 		i = ip->ip_hl << 2;
744 		off = offsetof(struct ip, ip_p);
745 		}
746 		break;
747 #endif /* AF_INET */
748 	case AF_INET6:
749 		i = sizeof(struct ip6_hdr);
750 		off = offsetof(struct ip6_hdr, ip6_nxt);
751 		break;
752 	default:
753 		DPRINTF(("%s: unsupported protocol family %u\n",
754 				 __func__, dst->sa.sa_family));
755 		error = EPFNOSUPPORT;
756 		IPSEC6STAT_INC(ips_out_inval);
757 		goto bad;
758 	}
759 	error = (*sav->tdb_xform->xf_output)(m, isr, NULL, i, off);
760 	IPSECREQUEST_UNLOCK(isr);
761 	return error;
762 bad:
763 
764 	if (isr)
765 		IPSECREQUEST_UNLOCK(isr);
766 	if (m)
767 		m_freem(m);
768 	return error;
769 }
770 #endif /*INET6*/
771