xref: /netbsd-src/sys/netipsec/ipsec_output.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /*	$NetBSD: ipsec_output.c,v 1.80 2018/05/31 15:06:45 maxv 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: 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 1.80 2018/05/31 15:06:45 maxv Exp $");
33 
34 #if defined(_KERNEL_OPT)
35 #include "opt_inet.h"
36 #include "opt_net_mpsafe.h"
37 #endif
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/mbuf.h>
42 #include <sys/domain.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/errno.h>
46 #include <sys/syslog.h>
47 
48 #include <net/if.h>
49 #include <net/route.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 
58 #include <netinet/ip6.h>
59 #ifdef INET6
60 #include <netinet6/ip6_var.h>
61 #endif
62 #include <netinet/in_pcb.h>
63 #ifdef INET6
64 #include <netinet/icmp6.h>
65 #endif
66 #include <netinet/udp.h>
67 
68 #include <netipsec/ipsec.h>
69 #include <netipsec/ipsec_var.h>
70 #include <netipsec/ipsec_private.h>
71 #ifdef INET6
72 #include <netipsec/ipsec6.h>
73 #endif
74 #include <netipsec/ah_var.h>
75 #include <netipsec/esp_var.h>
76 #include <netipsec/ipcomp_var.h>
77 
78 #include <netipsec/xform.h>
79 
80 #include <netipsec/key.h>
81 #include <netipsec/keydb.h>
82 #include <netipsec/key_debug.h>
83 
84 static percpu_t *ipsec_rtcache_percpu __cacheline_aligned;
85 
86 /*
87  * Add a IPSEC_OUT_DONE tag to mark that we have finished the ipsec processing
88  * It will be used by ip{,6}_output to check if we have already or not
89  * processed this packet.
90  */
91 static int
92 ipsec_register_done(struct mbuf *m, int *error)
93 {
94 	struct m_tag *mtag;
95 
96 	mtag = m_tag_get(PACKET_TAG_IPSEC_OUT_DONE, 0, M_NOWAIT);
97 	if (mtag == NULL) {
98 		IPSECLOG(LOG_DEBUG, "could not get packet tag\n");
99 		*error = ENOMEM;
100 		return -1;
101 	}
102 
103 	m_tag_prepend(m, mtag);
104 	return 0;
105 }
106 
107 static int
108 ipsec_reinject_ipstack(struct mbuf *m, int af)
109 {
110 	int rv = -1;
111 	struct route *ro;
112 
113 	KASSERT(af == AF_INET || af == AF_INET6);
114 
115 	KERNEL_LOCK_UNLESS_NET_MPSAFE();
116 	ro = percpu_getref(ipsec_rtcache_percpu);
117 	switch (af) {
118 #ifdef INET
119 	case AF_INET:
120 		rv = ip_output(m, NULL, ro, IP_RAWOUTPUT|IP_NOIPNEWID,
121 		    NULL, NULL);
122 		break;
123 #endif
124 #ifdef INET6
125 	case AF_INET6:
126 		/*
127 		 * We don't need massage, IPv6 header fields are always in
128 		 * net endian.
129 		 */
130 		rv = ip6_output(m, NULL, ro, 0, NULL, NULL, NULL);
131 		break;
132 #endif
133 	}
134 	percpu_putref(ipsec_rtcache_percpu);
135 	KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
136 
137 	return rv;
138 }
139 
140 int
141 ipsec_process_done(struct mbuf *m, const struct ipsecrequest *isr,
142     struct secasvar *sav)
143 {
144 	struct secasindex *saidx;
145 	int error;
146 #ifdef INET
147 	struct ip *ip;
148 #endif
149 #ifdef INET6
150 	struct ip6_hdr *ip6;
151 #endif
152 	struct mbuf *mo;
153 	struct udphdr *udp = NULL;
154 	int hlen, roff;
155 
156 	KASSERT(m != NULL);
157 	KASSERT(isr != NULL);
158 	KASSERT(sav != NULL);
159 
160 	saidx = &sav->sah->saidx;
161 
162 	if (sav->natt_type != 0) {
163 		ip = mtod(m, struct ip *);
164 
165 		hlen = sizeof(struct udphdr);
166 
167 		mo = m_makespace(m, sizeof(struct ip), hlen, &roff);
168 		if (mo == NULL) {
169 			char buf[IPSEC_ADDRSTRLEN];
170 			IPSECLOG(LOG_DEBUG,
171 			    "failed to inject %u byte UDP for SA %s/%08lx\n",
172 			    hlen, ipsec_address(&saidx->dst, buf, sizeof(buf)),
173 			    (u_long)ntohl(sav->spi));
174 			error = ENOBUFS;
175 			goto bad;
176 		}
177 
178 		udp = (struct udphdr *)(mtod(mo, char *) + roff);
179 		udp->uh_sport = key_portfromsaddr(&saidx->src);
180 		udp->uh_dport = key_portfromsaddr(&saidx->dst);
181 		udp->uh_sum = 0;
182 		udp->uh_ulen = htons(m->m_pkthdr.len - (ip->ip_hl << 2));
183 	}
184 
185 	/*
186 	 * Fix the header length, for AH processing.
187 	 */
188 	switch (saidx->dst.sa.sa_family) {
189 #ifdef INET
190 	case AF_INET:
191 		ip = mtod(m, struct ip *);
192 		ip->ip_len = htons(m->m_pkthdr.len);
193 		if (sav->natt_type != 0)
194 			ip->ip_p = IPPROTO_UDP;
195 		break;
196 #endif
197 #ifdef INET6
198 	case AF_INET6:
199 		if (m->m_pkthdr.len < sizeof(struct ip6_hdr)) {
200 			error = ENXIO;
201 			goto bad;
202 		}
203 		if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
204 			/* No jumbogram support. */
205 			error = ENXIO;	/*?*/
206 			goto bad;
207 		}
208 		ip6 = mtod(m, struct ip6_hdr *);
209 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
210 		if (sav->natt_type != 0)
211 			ip6->ip6_nxt = IPPROTO_UDP;
212 		break;
213 #endif
214 	default:
215 		IPSECLOG(LOG_DEBUG, "unknown protocol family %u\n",
216 		    saidx->dst.sa.sa_family);
217 		error = ENXIO;
218 		goto bad;
219 	}
220 
221 	key_sa_recordxfer(sav, m);
222 
223 	/*
224 	 * If there's another (bundled) SA to apply, do so.
225 	 * Note that this puts a burden on the kernel stack size.
226 	 * If this is a problem we'll need to introduce a queue
227 	 * to set the packet on so we can unwind the stack before
228 	 * doing further processing.
229 	 */
230 	if (isr->next) {
231 		IPSEC_STATINC(IPSEC_STAT_OUT_BUNDLESA);
232 		switch (saidx->dst.sa.sa_family) {
233 #ifdef INET
234 		case AF_INET:
235 			return ipsec4_process_packet(m, isr->next, NULL);
236 #endif
237 #ifdef INET6
238 		case AF_INET6:
239 			return ipsec6_process_packet(m, isr->next);
240 #endif
241 		default:
242 			IPSECLOG(LOG_DEBUG, "unknown protocol family %u\n",
243 			    saidx->dst.sa.sa_family);
244 			error = ENXIO;
245 			goto bad;
246 		}
247 	}
248 
249 	/*
250 	 * We're done with IPsec processing, mark the packet as processed,
251 	 * and transmit it using the appropriate network protocol
252 	 * (IPv4/IPv6).
253 	 */
254 
255 	if (ipsec_register_done(m, &error) < 0)
256 		goto bad;
257 
258 	return ipsec_reinject_ipstack(m, saidx->dst.sa.sa_family);
259 
260 bad:
261 	m_freem(m);
262 	return error;
263 }
264 
265 static void
266 ipsec_fill_saidx_bymbuf(struct secasindex *saidx, const struct mbuf *m,
267     const int af)
268 {
269 
270 	if (af == AF_INET) {
271 		struct sockaddr_in *sin;
272 		struct ip *ip = mtod(m, struct ip *);
273 
274 		if (saidx->src.sa.sa_len == 0) {
275 			sin = &saidx->src.sin;
276 			sin->sin_len = sizeof(*sin);
277 			sin->sin_family = AF_INET;
278 			sin->sin_port = IPSEC_PORT_ANY;
279 			sin->sin_addr = ip->ip_src;
280 		}
281 		if (saidx->dst.sa.sa_len == 0) {
282 			sin = &saidx->dst.sin;
283 			sin->sin_len = sizeof(*sin);
284 			sin->sin_family = AF_INET;
285 			sin->sin_port = IPSEC_PORT_ANY;
286 			sin->sin_addr = ip->ip_dst;
287 		}
288 	} else {
289 		struct sockaddr_in6 *sin6;
290 		struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
291 
292 		if (saidx->src.sin6.sin6_len == 0) {
293 			sin6 = (struct sockaddr_in6 *)&saidx->src;
294 			sin6->sin6_len = sizeof(*sin6);
295 			sin6->sin6_family = AF_INET6;
296 			sin6->sin6_port = IPSEC_PORT_ANY;
297 			sin6->sin6_addr = ip6->ip6_src;
298 			if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src)) {
299 				/* fix scope id for comparing SPD */
300 				sin6->sin6_addr.s6_addr16[1] = 0;
301 				sin6->sin6_scope_id =
302 				    ntohs(ip6->ip6_src.s6_addr16[1]);
303 			}
304 		}
305 		if (saidx->dst.sin6.sin6_len == 0) {
306 			sin6 = (struct sockaddr_in6 *)&saidx->dst;
307 			sin6->sin6_len = sizeof(*sin6);
308 			sin6->sin6_family = AF_INET6;
309 			sin6->sin6_port = IPSEC_PORT_ANY;
310 			sin6->sin6_addr = ip6->ip6_dst;
311 			if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst)) {
312 				/* fix scope id for comparing SPD */
313 				sin6->sin6_addr.s6_addr16[1] = 0;
314 				sin6->sin6_scope_id =
315 				    ntohs(ip6->ip6_dst.s6_addr16[1]);
316 			}
317 		}
318 	}
319 }
320 
321 struct secasvar *
322 ipsec_lookup_sa(const struct ipsecrequest *isr, const struct mbuf *m)
323 {
324 	struct secasindex saidx;
325 
326 	saidx = isr->saidx;
327 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
328 		/* Fillin unspecified SA peers only for transport mode */
329 		ipsec_fill_saidx_bymbuf(&saidx, m, isr->saidx.dst.sa.sa_family);
330 	}
331 
332 	return key_lookup_sa_bysaidx(&saidx);
333 }
334 
335 /*
336  * ipsec_nextisr can return :
337  * - isr == NULL and error != 0 => something is bad : the packet must be
338  *   discarded
339  * - isr == NULL and error == 0 => no more rules to apply, ipsec processing
340  *   is done, reinject it in ip stack
341  * - isr != NULL (error == 0) => we need to apply one rule to the packet
342  */
343 static const struct ipsecrequest *
344 ipsec_nextisr(struct mbuf *m, const struct ipsecrequest *isr, int af,
345     int *error, struct secasvar **ret)
346 {
347 #define	IPSEC_OSTAT(type)						\
348 do {									\
349 	switch (isr->saidx.proto) {					\
350 	case IPPROTO_ESP:						\
351 		ESP_STATINC(ESP_STAT_ ## type);				\
352 		break;							\
353 	case IPPROTO_AH:						\
354 		AH_STATINC(AH_STAT_ ## type);				\
355 		break;							\
356 	default:							\
357 		IPCOMP_STATINC(IPCOMP_STAT_ ## type);			\
358 		break;							\
359 	}								\
360 } while (/*CONSTCOND*/0)
361 
362 	struct secasvar *sav = NULL;
363 	struct secasindex saidx;
364 
365 	KASSERTMSG(af == AF_INET || af == AF_INET6,
366 	    "invalid address family %u", af);
367 again:
368 	/*
369 	 * Craft SA index to search for proper SA.  Note that
370 	 * we only fillin unspecified SA peers for transport
371 	 * mode; for tunnel mode they must already be filled in.
372 	 */
373 	saidx = isr->saidx;
374 	if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) {
375 		/* Fillin unspecified SA peers only for transport mode */
376 		ipsec_fill_saidx_bymbuf(&saidx, m, af);
377 	}
378 
379 	/*
380 	 * Lookup SA and validate it.
381 	 */
382 	*error = key_checkrequest(isr, &saidx, &sav);
383 	if (*error != 0) {
384 		/*
385 		 * IPsec processing is required, but no SA found.
386 		 * I assume that key_acquire() had been called
387 		 * to get/establish the SA. Here I discard
388 		 * this packet because it is responsibility for
389 		 * upper layer to retransmit the packet.
390 		 */
391 		IPSEC_STATINC(IPSEC_STAT_OUT_NOSA);
392 		goto bad;
393 	}
394 	/* sav may be NULL here if we have an USE rule */
395 	if (sav == NULL) {
396 		KASSERTMSG(ipsec_get_reqlevel(isr) == IPSEC_LEVEL_USE,
397 		    "no SA found, but required; level %u",
398 		    ipsec_get_reqlevel(isr));
399 		isr = isr->next;
400 		/*
401 		 * No more rules to apply, return NULL isr and no error.
402 		 * It can happen when the last rules are USE rules.
403 		 */
404 		if (isr == NULL) {
405 			*ret = NULL;
406 			*error = 0;
407 			return isr;
408 		}
409 		goto again;
410 	}
411 
412 	/*
413 	 * Check system global policy controls.
414 	 */
415 	if ((isr->saidx.proto == IPPROTO_ESP && !esp_enable) ||
416 	    (isr->saidx.proto == IPPROTO_AH && !ah_enable) ||
417 	    (isr->saidx.proto == IPPROTO_IPCOMP && !ipcomp_enable)) {
418 		IPSECLOG(LOG_DEBUG, "IPsec outbound packet dropped due"
419 		    " to policy (check your sysctls)\n");
420 		IPSEC_OSTAT(PDROPS);
421 		*error = EHOSTUNREACH;
422 		KEY_SA_UNREF(&sav);
423 		goto bad;
424 	}
425 
426 	/*
427 	 * Sanity check the SA contents for the caller
428 	 * before they invoke the xform output method.
429 	 */
430 	KASSERT(sav->tdb_xform != NULL);
431 	*ret = sav;
432 	return isr;
433 
434 bad:
435 	KASSERTMSG(*error != 0, "error return w/ no error code");
436 	return NULL;
437 #undef IPSEC_OSTAT
438 }
439 
440 #ifdef INET
441 /*
442  * IPsec output logic for IPv4.
443  */
444 int
445 ipsec4_process_packet(struct mbuf *m, const struct ipsecrequest *isr,
446     u_long *mtu)
447 {
448 	struct secasvar *sav = NULL;
449 	struct ip *ip;
450 	int s, error, i, off;
451 	union sockaddr_union *dst;
452 	int setdf;
453 
454 	KASSERT(m != NULL);
455 	KASSERT(m->m_nextpkt == NULL);
456 	KASSERT(isr != NULL);
457 
458 	s = splsoftnet();	/* insure SA contents don't change */
459 
460 	isr = ipsec_nextisr(m, isr, AF_INET, &error, &sav);
461 	if (isr == NULL) {
462 		if (error != 0) {
463 			goto bad;
464 		} else {
465 			if (ipsec_register_done(m, &error) < 0)
466 				goto bad;
467 
468 			splx(s);
469 			return ipsec_reinject_ipstack(m, AF_INET);
470 		}
471 	}
472 	KASSERT(sav != NULL);
473 
474 	if (m->m_len < sizeof(struct ip) &&
475 	    (m = m_pullup(m, sizeof(struct ip))) == NULL) {
476 		error = ENOBUFS;
477 		goto unrefsav;
478 	}
479 
480 	/*
481 	 * Check if we need to handle NAT-T fragmentation.
482 	 */
483 	if (isr == isr->sp->req) { /* Check only if called from ipsec4_output */
484 		KASSERT(mtu != NULL);
485 		ip = mtod(m, struct ip *);
486 		if (!(sav->natt_type & UDP_ENCAP_ESPINUDP)) {
487 			goto noneed;
488 		}
489 		if (ntohs(ip->ip_len) <= sav->esp_frag)
490 			goto noneed;
491 		*mtu = sav->esp_frag;
492 		KEY_SA_UNREF(&sav);
493 		splx(s);
494 		return 0;
495 	}
496 noneed:
497 	dst = &sav->sah->saidx.dst;
498 
499 	/*
500 	 * Collect IP_DF state from the outer header.
501 	 */
502 	if (dst->sa.sa_family == AF_INET) {
503 		ip = mtod(m, struct ip *);
504 		/* Honor system-wide control of how to handle IP_DF */
505 		switch (ip4_ipsec_dfbit) {
506 		case 0:			/* clear in outer header */
507 		case 1:			/* set in outer header */
508 			setdf = ip4_ipsec_dfbit;
509 			break;
510 		default:		/* propagate to outer header */
511 			setdf = ip->ip_off;
512 			setdf = ntohs(setdf);
513 			setdf = htons(setdf & IP_DF);
514 			break;
515 		}
516 	} else {
517 		ip = NULL;		/* keep compiler happy */
518 		setdf = 0;
519 	}
520 
521 	/* Do the appropriate encapsulation, if necessary */
522 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
523 	    dst->sa.sa_family != AF_INET ||	    /* PF mismatch */
524 	    (dst->sa.sa_family == AF_INET &&	    /* Proxy */
525 	     dst->sin.sin_addr.s_addr != INADDR_ANY &&
526 	     dst->sin.sin_addr.s_addr != ip->ip_dst.s_addr)) {
527 		struct mbuf *mp;
528 
529 		/* Fix IPv4 header checksum and length */
530 		ip = mtod(m, struct ip *);
531 		ip->ip_len = htons(m->m_pkthdr.len);
532 		ip->ip_sum = 0;
533 		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
534 
535 		/* Encapsulate the packet */
536 		error = ipip_output(m, sav, &mp);
537 		if (mp == NULL && !error) {
538 			/* Should never happen. */
539 			IPSECLOG(LOG_DEBUG,
540 			    "ipip_output returns no mbuf and no error!");
541 			error = EFAULT;
542 		}
543 		if (error) {
544 			if (mp) {
545 				/* XXX: Should never happen! */
546 				m_freem(mp);
547 			}
548 			m = NULL; /* ipip_output() already freed it */
549 			goto unrefsav;
550 		}
551 		m = mp, mp = NULL;
552 
553 		/*
554 		 * ipip_output clears IP_DF in the new header.  If
555 		 * we need to propagate IP_DF from the outer header,
556 		 * then we have to do it here.
557 		 *
558 		 * XXX shouldn't assume what ipip_output does.
559 		 */
560 		if (dst->sa.sa_family == AF_INET && setdf) {
561 			if (m->m_len < sizeof(struct ip) &&
562 			    (m = m_pullup(m, sizeof(struct ip))) == NULL) {
563 				error = ENOBUFS;
564 				goto unrefsav;
565 			}
566 			ip = mtod(m, struct ip *);
567 			ip->ip_off |= htons(IP_DF);
568 		}
569 	}
570 
571 	/*
572 	 * Dispatch to the appropriate IPsec transform logic.  The
573 	 * packet will be returned for transmission after crypto
574 	 * processing, etc. are completed.  For encapsulation we
575 	 * bypass this call because of the explicit call done above
576 	 * (necessary to deal with IP_DF handling for IPv4).
577 	 *
578 	 * NB: m & sav are ``passed to caller'' who's reponsible for
579 	 *     for reclaiming their resources.
580 	 */
581 	if (sav->tdb_xform->xf_type != XF_IP4) {
582 		if (dst->sa.sa_family == AF_INET) {
583 			ip = mtod(m, struct ip *);
584 			i = ip->ip_hl << 2;
585 			off = offsetof(struct ip, ip_p);
586 		} else {
587 			i = sizeof(struct ip6_hdr);
588 			off = offsetof(struct ip6_hdr, ip6_nxt);
589 		}
590 		error = (*sav->tdb_xform->xf_output)(m, isr, sav, i, off);
591 	} else {
592 		error = ipsec_process_done(m, isr, sav);
593 	}
594 	KEY_SA_UNREF(&sav);
595 	splx(s);
596 	return error;
597 
598 unrefsav:
599 	KEY_SA_UNREF(&sav);
600 bad:
601 	splx(s);
602 	if (m)
603 		m_freem(m);
604 	return error;
605 }
606 #endif
607 
608 #ifdef INET6
609 static int
610 compute_ipsec_pos(struct mbuf *m, int *i, int *off)
611 {
612 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
613 	struct ip6_ext ip6e;
614 	int dstopt = 0;
615 	int nxt;
616 
617 	*i = sizeof(struct ip6_hdr);
618 	*off = offsetof(struct ip6_hdr, ip6_nxt);
619 	nxt = ip6->ip6_nxt;
620 
621 	/*
622 	 * chase mbuf chain to find the appropriate place to
623 	 * put AH/ESP/IPcomp header.
624 	 *     IPv6 hbh dest1 rthdr ah* [esp* dest2 payload]
625 	 */
626 	while (1) {
627 		switch (nxt) {
628 		case IPPROTO_AH:
629 		case IPPROTO_ESP:
630 		case IPPROTO_IPCOMP:
631 			/*
632 			 * We should not skip security header added
633 			 * beforehand.
634 			 */
635 			return 0;
636 
637 		case IPPROTO_HOPOPTS:
638 		case IPPROTO_DSTOPTS:
639 		case IPPROTO_ROUTING:
640 			if (*i + sizeof(ip6e) > m->m_pkthdr.len) {
641 				return EINVAL;
642 			}
643 
644 			/*
645 			 * If we see 2nd destination option header,
646 			 * we should stop there.
647 			 */
648 			if (nxt == IPPROTO_DSTOPTS && dstopt)
649 				return 0;
650 
651 			if (nxt == IPPROTO_DSTOPTS) {
652 				/*
653 				 * Seen 1st or 2nd destination option.
654 				 * next time we see one, it must be 2nd.
655 				 */
656 				dstopt = 1;
657 			} else if (nxt == IPPROTO_ROUTING) {
658 				/*
659 				 * If we see destination option next
660 				 * time, it must be dest2.
661 				 */
662 				dstopt = 2;
663 			}
664 
665 			/* skip this header */
666 			m_copydata(m, *i, sizeof(ip6e), &ip6e);
667 			nxt = ip6e.ip6e_nxt;
668 			*off = *i + offsetof(struct ip6_ext, ip6e_nxt);
669 			*i += (ip6e.ip6e_len + 1) << 3;
670 			if (*i > m->m_pkthdr.len) {
671 				return EINVAL;
672 			}
673 			break;
674 		default:
675 			return 0;
676 		}
677 	}
678 
679 	return 0;
680 }
681 
682 static int
683 in6_sa_equal_addrwithscope(const struct sockaddr_in6 *sa,
684     const struct in6_addr *ia)
685 {
686 	struct in6_addr ia2;
687 
688 	memcpy(&ia2, &sa->sin6_addr, sizeof(ia2));
689 	if (IN6_IS_SCOPE_LINKLOCAL(&sa->sin6_addr))
690 		ia2.s6_addr16[1] = htons(sa->sin6_scope_id);
691 
692 	return IN6_ARE_ADDR_EQUAL(ia, &ia2);
693 }
694 
695 int
696 ipsec6_process_packet(struct mbuf *m, const struct ipsecrequest *isr)
697 {
698 	struct secasvar *sav = NULL;
699 	struct ip6_hdr *ip6;
700 	int s, error, i, off;
701 	union sockaddr_union *dst;
702 
703 	KASSERT(m != NULL);
704 	KASSERT(m->m_nextpkt == NULL);
705 	KASSERT(isr != NULL);
706 
707 	s = splsoftnet();   /* insure SA contents don't change */
708 
709 	isr = ipsec_nextisr(m, isr, AF_INET6, &error, &sav);
710 	if (isr == NULL) {
711 		if (error != 0) {
712 			/* XXX Should we send a notification ? */
713 			goto bad;
714 		} else {
715 			if (ipsec_register_done(m, &error) < 0)
716 				goto bad;
717 
718 			splx(s);
719 			return ipsec_reinject_ipstack(m, AF_INET6);
720 		}
721 	}
722 
723 	KASSERT(sav != NULL);
724 	dst = &sav->sah->saidx.dst;
725 
726 	if (m->m_len < sizeof(struct ip6_hdr)) {
727 		if ((m = m_pullup(m,sizeof(struct ip6_hdr))) == NULL) {
728 			error = ENOBUFS;
729 			goto unrefsav;
730 		}
731 	}
732 	ip6 = mtod(m, struct ip6_hdr *);
733 
734 	/* Do the appropriate encapsulation, if necessary */
735 	if (isr->saidx.mode == IPSEC_MODE_TUNNEL || /* Tunnel requ'd */
736 	    dst->sa.sa_family != AF_INET6 ||        /* AF mismatch */
737 	    ((dst->sa.sa_family == AF_INET6) &&
738 	     (!IN6_IS_ADDR_UNSPECIFIED(&dst->sin6.sin6_addr)) &&
739 	     (!in6_sa_equal_addrwithscope(&dst->sin6, &ip6->ip6_dst)))) {
740 		struct mbuf *mp;
741 
742 		if (m->m_pkthdr.len - sizeof(*ip6) > IPV6_MAXPACKET) {
743 			/* No jumbogram support. */
744 			error = ENXIO;   /*XXX*/
745 			goto unrefsav;
746 		}
747 
748 		/* Fix IPv6 header payload length. */
749 		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
750 
751 		/* Encapsulate the packet */
752 		error = ipip_output(m, sav, &mp);
753 		if (mp == NULL && !error) {
754 			/* Should never happen. */
755 			IPSECLOG(LOG_DEBUG,
756 			    "ipip_output returns no mbuf and no error!");
757 			error = EFAULT;
758 		}
759 
760 		if (error) {
761 			if (mp) {
762 				/* XXX: Should never happen! */
763 				m_freem(mp);
764 			}
765 			m = NULL; /* ipip_output() already freed it */
766 			goto unrefsav;
767 		}
768 
769 		m = mp;
770 		mp = NULL;
771 	}
772 
773 	if (dst->sa.sa_family == AF_INET) {
774 		struct ip *ip;
775 		ip = mtod(m, struct ip *);
776 		i = ip->ip_hl << 2;
777 		off = offsetof(struct ip, ip_p);
778 	} else {
779 		error = compute_ipsec_pos(m, &i, &off);
780 		if (error)
781 			goto unrefsav;
782 	}
783 	error = (*sav->tdb_xform->xf_output)(m, isr, sav, i, off);
784 	KEY_SA_UNREF(&sav);
785 	splx(s);
786 	return error;
787 
788 unrefsav:
789 	KEY_SA_UNREF(&sav);
790 bad:
791 	splx(s);
792 	if (m)
793 		m_freem(m);
794 	return error;
795 }
796 #endif /* INET6 */
797 
798 void
799 ipsec_output_init(void)
800 {
801 
802 	ipsec_rtcache_percpu = percpu_alloc(sizeof(struct route));
803 }
804