xform_ipip.c revision 240233 
1/*	$FreeBSD: head/sys/netipsec/xform_ipip.c 240233 2012-09-08 06:41:54Z glebius $	*/
2/*	$OpenBSD: ip_ipip.c,v 1.25 2002/06/10 18:04:55 itojun Exp $ */
3/*-
4 * The authors of this code are John Ioannidis (ji@tla.org),
5 * Angelos D. Keromytis (kermit@csd.uch.gr) and
6 * Niels Provos (provos@physnet.uni-hamburg.de).
7 *
8 * The original version of this code was written by John Ioannidis
9 * for BSD/OS in Athens, Greece, in November 1995.
10 *
11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
12 * by Angelos D. Keromytis.
13 *
14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
15 * and Niels Provos.
16 *
17 * Additional features in 1999 by Angelos D. Keromytis.
18 *
19 * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
20 * Angelos D. Keromytis and Niels Provos.
21 * Copyright (c) 2001, Angelos D. Keromytis.
22 *
23 * Permission to use, copy, and modify this software with or without fee
24 * is hereby granted, provided that this entire notice is included in
25 * all copies of any software which is or includes a copy or
26 * modification of this software.
27 * You may use this code under the GNU public license if you so wish. Please
28 * contribute changes back to the authors under this freer than GPL license
29 * so that we may further the use of strong encryption without limitations to
30 * all.
31 *
32 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
33 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
34 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
35 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
36 * PURPOSE.
37 */
38
39/*
40 * IP-inside-IP processing
41 */
42#include "opt_inet.h"
43#include "opt_inet6.h"
44#include "opt_enc.h"
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/mbuf.h>
49#include <sys/socket.h>
50#include <sys/kernel.h>
51#include <sys/protosw.h>
52#include <sys/sysctl.h>
53
54#include <net/if.h>
55#include <net/pfil.h>
56#include <net/route.h>
57#include <net/netisr.h>
58#include <net/vnet.h>
59
60#include <netinet/in.h>
61#include <netinet/in_systm.h>
62#include <netinet/in_var.h>
63#include <netinet/ip.h>
64#include <netinet/ip_ecn.h>
65#include <netinet/ip_var.h>
66#include <netinet/ip_encap.h>
67#ifdef MROUTING
68#include <netinet/ip_mroute.h>
69#endif
70
71#include <netipsec/ipsec.h>
72#include <netipsec/xform.h>
73
74#include <netipsec/ipip_var.h>
75
76#ifdef INET6
77#include <netinet/ip6.h>
78#include <netipsec/ipsec6.h>
79#include <netinet6/ip6_ecn.h>
80#include <netinet6/in6_var.h>
81#include <netinet6/ip6protosw.h>
82#endif
83
84#include <netipsec/key.h>
85#include <netipsec/key_debug.h>
86
87#include <machine/stdarg.h>
88
89/*
90 * We can control the acceptance of IP4 packets by altering the sysctl
91 * net.inet.ipip.allow value.  Zero means drop them, all else is acceptance.
92 */
93VNET_DEFINE(int, ipip_allow) = 0;
94VNET_DEFINE(struct ipipstat, ipipstat);
95
96SYSCTL_DECL(_net_inet_ipip);
97SYSCTL_VNET_INT(_net_inet_ipip, OID_AUTO,
98	ipip_allow,	CTLFLAG_RW,	&VNET_NAME(ipip_allow),	0, "");
99SYSCTL_VNET_STRUCT(_net_inet_ipip, IPSECCTL_STATS,
100	stats,		CTLFLAG_RD,	&VNET_NAME(ipipstat),	ipipstat, "");
101
102/* XXX IPCOMP */
103#define	M_IPSEC	(M_AUTHIPHDR|M_AUTHIPDGM|M_DECRYPTED)
104
105static void _ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp);
106
107#ifdef INET6
108/*
109 * Really only a wrapper for ipip_input(), for use with IPv6.
110 */
111int
112ip4_input6(struct mbuf **m, int *offp, int proto)
113{
114#if 0
115	/* If we do not accept IP-in-IP explicitly, drop.  */
116	if (!V_ipip_allow && ((*m)->m_flags & M_IPSEC) == 0) {
117		DPRINTF(("%s: dropped due to policy\n", __func__));
118		V_ipipstat.ipips_pdrops++;
119		m_freem(*m);
120		return IPPROTO_DONE;
121	}
122#endif
123	_ipip_input(*m, *offp, NULL);
124	return IPPROTO_DONE;
125}
126#endif /* INET6 */
127
128#ifdef INET
129/*
130 * Really only a wrapper for ipip_input(), for use with IPv4.
131 */
132void
133ip4_input(struct mbuf *m, int off)
134{
135#if 0
136	/* If we do not accept IP-in-IP explicitly, drop.  */
137	if (!V_ipip_allow && (m->m_flags & M_IPSEC) == 0) {
138		DPRINTF(("%s: dropped due to policy\n", __func__));
139		V_ipipstat.ipips_pdrops++;
140		m_freem(m);
141		return;
142	}
143#endif
144	_ipip_input(m, off, NULL);
145}
146#endif /* INET */
147
148/*
149 * ipip_input gets called when we receive an IP{46} encapsulated packet,
150 * either because we got it at a real interface, or because AH or ESP
151 * were being used in tunnel mode (in which case the rcvif element will
152 * contain the address of the encX interface associated with the tunnel.
153 */
154
155static void
156_ipip_input(struct mbuf *m, int iphlen, struct ifnet *gifp)
157{
158#ifdef INET
159	register struct sockaddr_in *sin;
160#endif
161	register struct ifnet *ifp;
162	register struct ifaddr *ifa;
163	struct ip *ipo;
164#ifdef INET6
165	register struct sockaddr_in6 *sin6;
166	struct ip6_hdr *ip6 = NULL;
167	u_int8_t itos;
168#endif
169	u_int8_t nxt;
170	int isr;
171	u_int8_t otos;
172	u_int8_t v;
173	int hlen;
174
175	V_ipipstat.ipips_ipackets++;
176
177	m_copydata(m, 0, 1, &v);
178
179	switch (v >> 4) {
180#ifdef INET
181        case 4:
182		hlen = sizeof(struct ip);
183		break;
184#endif /* INET */
185#ifdef INET6
186        case 6:
187		hlen = sizeof(struct ip6_hdr);
188		break;
189#endif
190        default:
191		V_ipipstat.ipips_family++;
192		m_freem(m);
193		return /* EAFNOSUPPORT */;
194	}
195
196	/* Bring the IP header in the first mbuf, if not there already */
197	if (m->m_len < hlen) {
198		if ((m = m_pullup(m, hlen)) == NULL) {
199			DPRINTF(("%s: m_pullup (1) failed\n", __func__));
200			V_ipipstat.ipips_hdrops++;
201			return;
202		}
203	}
204
205	ipo = mtod(m, struct ip *);
206
207#ifdef MROUTING
208	if (ipo->ip_v == IPVERSION && ipo->ip_p == IPPROTO_IPV4) {
209		if (IN_MULTICAST(((struct ip *)((char *) ipo + iphlen))->ip_dst.s_addr)) {
210			ipip_mroute_input (m, iphlen);
211			return;
212		}
213	}
214#endif /* MROUTING */
215
216	/* Keep outer ecn field. */
217	switch (v >> 4) {
218#ifdef INET
219	case 4:
220		otos = ipo->ip_tos;
221		break;
222#endif /* INET */
223#ifdef INET6
224	case 6:
225		otos = (ntohl(mtod(m, struct ip6_hdr *)->ip6_flow) >> 20) & 0xff;
226		break;
227#endif
228	default:
229		panic("ipip_input: unknown ip version %u (outer)", v>>4);
230	}
231
232	/* Remove outer IP header */
233	m_adj(m, iphlen);
234
235	/* Sanity check */
236	if (m->m_pkthdr.len < sizeof(struct ip))  {
237		V_ipipstat.ipips_hdrops++;
238		m_freem(m);
239		return;
240	}
241
242	m_copydata(m, 0, 1, &v);
243
244	switch (v >> 4) {
245#ifdef INET
246        case 4:
247		hlen = sizeof(struct ip);
248		break;
249#endif /* INET */
250
251#ifdef INET6
252        case 6:
253		hlen = sizeof(struct ip6_hdr);
254		break;
255#endif
256	default:
257		V_ipipstat.ipips_family++;
258		m_freem(m);
259		return; /* EAFNOSUPPORT */
260	}
261
262	/*
263	 * Bring the inner IP header in the first mbuf, if not there already.
264	 */
265	if (m->m_len < hlen) {
266		if ((m = m_pullup(m, hlen)) == NULL) {
267			DPRINTF(("%s: m_pullup (2) failed\n", __func__));
268			V_ipipstat.ipips_hdrops++;
269			return;
270		}
271	}
272
273	/*
274	 * RFC 1853 specifies that the inner TTL should not be touched on
275	 * decapsulation. There's no reason this comment should be here, but
276	 * this is as good as any a position.
277	 */
278
279	/* Some sanity checks in the inner IP header */
280	switch (v >> 4) {
281#ifdef INET
282    	case 4:
283                ipo = mtod(m, struct ip *);
284                nxt = ipo->ip_p;
285		ip_ecn_egress(V_ip4_ipsec_ecn, &otos, &ipo->ip_tos);
286                break;
287#endif /* INET */
288#ifdef INET6
289    	case 6:
290                ip6 = (struct ip6_hdr *) ipo;
291                nxt = ip6->ip6_nxt;
292		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
293		ip_ecn_egress(V_ip6_ipsec_ecn, &otos, &itos);
294		ip6->ip6_flow &= ~htonl(0xff << 20);
295		ip6->ip6_flow |= htonl((u_int32_t) itos << 20);
296                break;
297#endif
298	default:
299		panic("ipip_input: unknown ip version %u (inner)", v>>4);
300	}
301
302	/* Check for local address spoofing. */
303	if ((m->m_pkthdr.rcvif == NULL ||
304	    !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) &&
305	    V_ipip_allow != 2) {
306	    	IFNET_RLOCK_NOSLEEP();
307		TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
308			TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
309#ifdef INET
310				if (ipo) {
311					if (ifa->ifa_addr->sa_family !=
312					    AF_INET)
313						continue;
314
315					sin = (struct sockaddr_in *) ifa->ifa_addr;
316
317					if (sin->sin_addr.s_addr ==
318					    ipo->ip_src.s_addr)	{
319						V_ipipstat.ipips_spoof++;
320						m_freem(m);
321						IFNET_RUNLOCK_NOSLEEP();
322						return;
323					}
324				}
325#endif /* INET */
326
327#ifdef INET6
328				if (ip6) {
329					if (ifa->ifa_addr->sa_family !=
330					    AF_INET6)
331						continue;
332
333					sin6 = (struct sockaddr_in6 *) ifa->ifa_addr;
334
335					if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr, &ip6->ip6_src)) {
336						V_ipipstat.ipips_spoof++;
337						m_freem(m);
338						IFNET_RUNLOCK_NOSLEEP();
339						return;
340					}
341
342				}
343#endif /* INET6 */
344			}
345		}
346		IFNET_RUNLOCK_NOSLEEP();
347	}
348
349	/* Statistics */
350	V_ipipstat.ipips_ibytes += m->m_pkthdr.len - iphlen;
351
352#ifdef DEV_ENC
353	switch (v >> 4) {
354#ifdef INET
355	case 4:
356		ipsec_bpf(m, NULL, AF_INET, ENC_IN|ENC_AFTER);
357		break;
358#endif
359#ifdef INET6
360	case 6:
361		ipsec_bpf(m, NULL, AF_INET6, ENC_IN|ENC_AFTER);
362		break;
363#endif
364	default:
365		panic("%s: bogus ip version %u", __func__, v>>4);
366	}
367	/* pass the mbuf to enc0 for packet filtering */
368	if (ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_AFTER) != 0)
369		return;
370#endif
371
372	/*
373	 * Interface pointer stays the same; if no IPsec processing has
374	 * been done (or will be done), this will point to a normal
375	 * interface. Otherwise, it'll point to an enc interface, which
376	 * will allow a packet filter to distinguish between secure and
377	 * untrusted packets.
378	 */
379
380	switch (v >> 4) {
381#ifdef INET
382	case 4:
383		isr = NETISR_IP;
384		break;
385#endif
386#ifdef INET6
387	case 6:
388		isr = NETISR_IPV6;
389		break;
390#endif
391	default:
392		panic("%s: bogus ip version %u", __func__, v>>4);
393	}
394
395	if (netisr_queue(isr, m)) {	/* (0) on success. */
396		V_ipipstat.ipips_qfull++;
397		DPRINTF(("%s: packet dropped because of full queue\n",
398			__func__));
399	}
400}
401
402int
403ipip_output(
404	struct mbuf *m,
405	struct ipsecrequest *isr,
406	struct mbuf **mp,
407	int skip,
408	int protoff
409)
410{
411	struct secasvar *sav;
412	u_int8_t tp, otos;
413	struct secasindex *saidx;
414	int error;
415#if defined(INET) || defined(INET6)
416	u_int8_t itos;
417#endif
418#ifdef INET
419	struct ip *ipo;
420#endif /* INET */
421#ifdef INET6
422	struct ip6_hdr *ip6, *ip6o;
423#endif /* INET6 */
424
425	sav = isr->sav;
426	IPSEC_ASSERT(sav != NULL, ("null SA"));
427	IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
428
429	/* XXX Deal with empty TDB source/destination addresses. */
430
431	m_copydata(m, 0, 1, &tp);
432	tp = (tp >> 4) & 0xff;  /* Get the IP version number. */
433
434	saidx = &sav->sah->saidx;
435	switch (saidx->dst.sa.sa_family) {
436#ifdef INET
437	case AF_INET:
438		if (saidx->src.sa.sa_family != AF_INET ||
439		    saidx->src.sin.sin_addr.s_addr == INADDR_ANY ||
440		    saidx->dst.sin.sin_addr.s_addr == INADDR_ANY) {
441			DPRINTF(("%s: unspecified tunnel endpoint "
442			    "address in SA %s/%08lx\n", __func__,
443			    ipsec_address(&saidx->dst),
444			    (u_long) ntohl(sav->spi)));
445			V_ipipstat.ipips_unspec++;
446			error = EINVAL;
447			goto bad;
448		}
449
450		M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
451		if (m == 0) {
452			DPRINTF(("%s: M_PREPEND failed\n", __func__));
453			V_ipipstat.ipips_hdrops++;
454			error = ENOBUFS;
455			goto bad;
456		}
457
458		ipo = mtod(m, struct ip *);
459
460		ipo->ip_v = IPVERSION;
461		ipo->ip_hl = 5;
462		ipo->ip_len = htons(m->m_pkthdr.len);
463		ipo->ip_ttl = V_ip_defttl;
464		ipo->ip_sum = 0;
465		ipo->ip_src = saidx->src.sin.sin_addr;
466		ipo->ip_dst = saidx->dst.sin.sin_addr;
467
468		ipo->ip_id = ip_newid();
469
470		/* If the inner protocol is IP... */
471		switch (tp) {
472		case IPVERSION:
473			/* Save ECN notification */
474			m_copydata(m, sizeof(struct ip) +
475			    offsetof(struct ip, ip_tos),
476			    sizeof(u_int8_t), (caddr_t) &itos);
477
478			ipo->ip_p = IPPROTO_IPIP;
479
480			/*
481			 * We should be keeping tunnel soft-state and
482			 * send back ICMPs if needed.
483			 */
484			m_copydata(m, sizeof(struct ip) +
485			    offsetof(struct ip, ip_off),
486			    sizeof(u_int16_t), (caddr_t) &ipo->ip_off);
487			ipo->ip_off = ntohs(ipo->ip_off);
488			ipo->ip_off &= ~(IP_DF | IP_MF | IP_OFFMASK);
489			ipo->ip_off = htons(ipo->ip_off);
490			break;
491#ifdef INET6
492		case (IPV6_VERSION >> 4):
493		{
494			u_int32_t itos32;
495
496			/* Save ECN notification. */
497			m_copydata(m, sizeof(struct ip) +
498			    offsetof(struct ip6_hdr, ip6_flow),
499			    sizeof(u_int32_t), (caddr_t) &itos32);
500			itos = ntohl(itos32) >> 20;
501			ipo->ip_p = IPPROTO_IPV6;
502			ipo->ip_off = 0;
503			break;
504		}
505#endif /* INET6 */
506		default:
507			goto nofamily;
508		}
509
510		otos = 0;
511		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
512		ipo->ip_tos = otos;
513		break;
514#endif /* INET */
515
516#ifdef INET6
517	case AF_INET6:
518		if (IN6_IS_ADDR_UNSPECIFIED(&saidx->dst.sin6.sin6_addr) ||
519		    saidx->src.sa.sa_family != AF_INET6 ||
520		    IN6_IS_ADDR_UNSPECIFIED(&saidx->src.sin6.sin6_addr)) {
521			DPRINTF(("%s: unspecified tunnel endpoint "
522			    "address in SA %s/%08lx\n", __func__,
523			    ipsec_address(&saidx->dst),
524			    (u_long) ntohl(sav->spi)));
525			V_ipipstat.ipips_unspec++;
526			error = ENOBUFS;
527			goto bad;
528		}
529
530		/* scoped address handling */
531		ip6 = mtod(m, struct ip6_hdr *);
532		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_src))
533			ip6->ip6_src.s6_addr16[1] = 0;
534		if (IN6_IS_SCOPE_LINKLOCAL(&ip6->ip6_dst))
535			ip6->ip6_dst.s6_addr16[1] = 0;
536
537		M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
538		if (m == 0) {
539			DPRINTF(("%s: M_PREPEND failed\n", __func__));
540			V_ipipstat.ipips_hdrops++;
541			error = ENOBUFS;
542			goto bad;
543		}
544
545		/* Initialize IPv6 header */
546		ip6o = mtod(m, struct ip6_hdr *);
547		ip6o->ip6_flow = 0;
548		ip6o->ip6_vfc &= ~IPV6_VERSION_MASK;
549		ip6o->ip6_vfc |= IPV6_VERSION;
550		ip6o->ip6_plen = htons(m->m_pkthdr.len);
551		ip6o->ip6_hlim = V_ip_defttl;
552		ip6o->ip6_dst = saidx->dst.sin6.sin6_addr;
553		ip6o->ip6_src = saidx->src.sin6.sin6_addr;
554
555		switch (tp) {
556#ifdef INET
557		case IPVERSION:
558			/* Save ECN notification */
559			m_copydata(m, sizeof(struct ip6_hdr) +
560			    offsetof(struct ip, ip_tos), sizeof(u_int8_t),
561			    (caddr_t) &itos);
562
563			/* This is really IPVERSION. */
564			ip6o->ip6_nxt = IPPROTO_IPIP;
565			break;
566#endif /* INET */
567		case (IPV6_VERSION >> 4):
568		{
569			u_int32_t itos32;
570
571			/* Save ECN notification. */
572			m_copydata(m, sizeof(struct ip6_hdr) +
573			    offsetof(struct ip6_hdr, ip6_flow),
574			    sizeof(u_int32_t), (caddr_t) &itos32);
575			itos = ntohl(itos32) >> 20;
576
577			ip6o->ip6_nxt = IPPROTO_IPV6;
578		}
579		default:
580			goto nofamily;
581		}
582
583		otos = 0;
584		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
585		ip6o->ip6_flow |= htonl((u_int32_t) otos << 20);
586		break;
587#endif /* INET6 */
588
589	default:
590nofamily:
591		DPRINTF(("%s: unsupported protocol family %u\n", __func__,
592		    saidx->dst.sa.sa_family));
593		V_ipipstat.ipips_family++;
594		error = EAFNOSUPPORT;		/* XXX diffs from openbsd */
595		goto bad;
596	}
597
598	V_ipipstat.ipips_opackets++;
599	*mp = m;
600
601#ifdef INET
602	if (saidx->dst.sa.sa_family == AF_INET) {
603#if 0
604		if (sav->tdb_xform->xf_type == XF_IP4)
605			tdb->tdb_cur_bytes +=
606			    m->m_pkthdr.len - sizeof(struct ip);
607#endif
608		V_ipipstat.ipips_obytes += m->m_pkthdr.len - sizeof(struct ip);
609	}
610#endif /* INET */
611
612#ifdef INET6
613	if (saidx->dst.sa.sa_family == AF_INET6) {
614#if 0
615		if (sav->tdb_xform->xf_type == XF_IP4)
616			tdb->tdb_cur_bytes +=
617			    m->m_pkthdr.len - sizeof(struct ip6_hdr);
618#endif
619		V_ipipstat.ipips_obytes +=
620		    m->m_pkthdr.len - sizeof(struct ip6_hdr);
621	}
622#endif /* INET6 */
623
624	return 0;
625bad:
626	if (m)
627		m_freem(m);
628	*mp = NULL;
629	return (error);
630}
631
632#ifdef IPSEC
633#if defined(INET) || defined(INET6)
634static int
635ipe4_init(struct secasvar *sav, struct xformsw *xsp)
636{
637	sav->tdb_xform = xsp;
638	return 0;
639}
640
641static int
642ipe4_zeroize(struct secasvar *sav)
643{
644	sav->tdb_xform = NULL;
645	return 0;
646}
647
648static int
649ipe4_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
650{
651	/* This is a rather serious mistake, so no conditional printing. */
652	printf("%s: should never be called\n", __func__);
653	if (m)
654		m_freem(m);
655	return EOPNOTSUPP;
656}
657
658static struct xformsw ipe4_xformsw = {
659	XF_IP4,		0,		"IPv4 Simple Encapsulation",
660	ipe4_init,	ipe4_zeroize,	ipe4_input,	ipip_output,
661};
662
663extern struct domain inetdomain;
664#endif /* INET || INET6 */
665#ifdef INET
666static struct protosw ipe4_protosw = {
667	.pr_type =	SOCK_RAW,
668	.pr_domain =	&inetdomain,
669	.pr_protocol =	IPPROTO_IPV4,
670	.pr_flags =	PR_ATOMIC|PR_ADDR|PR_LASTHDR,
671	.pr_input =	ip4_input,
672	.pr_ctloutput =	rip_ctloutput,
673	.pr_usrreqs =	&rip_usrreqs
674};
675#endif /* INET */
676#if defined(INET6) && defined(INET)
677static struct ip6protosw ipe6_protosw = {
678	.pr_type =	SOCK_RAW,
679	.pr_domain =	&inetdomain,
680	.pr_protocol =	IPPROTO_IPV6,
681	.pr_flags =	PR_ATOMIC|PR_ADDR|PR_LASTHDR,
682	.pr_input =	ip4_input6,
683	.pr_ctloutput =	rip_ctloutput,
684	.pr_usrreqs =	&rip_usrreqs
685};
686#endif /* INET6 && INET */
687
688#ifdef INET
689/*
690 * Check the encapsulated packet to see if we want it
691 */
692static int
693ipe4_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
694{
695	/*
696	 * Only take packets coming from IPSEC tunnels; the rest
697	 * must be handled by the gif tunnel code.  Note that we
698	 * also return a minimum priority when we want the packet
699	 * so any explicit gif tunnels take precedence.
700	 */
701	return ((m->m_flags & M_IPSEC) != 0 ? 1 : 0);
702}
703#endif /* INET */
704
705static void
706ipe4_attach(void)
707{
708
709	xform_register(&ipe4_xformsw);
710	/* attach to encapsulation framework */
711	/* XXX save return cookie for detach on module remove */
712#ifdef INET
713	(void) encap_attach_func(AF_INET, -1,
714		ipe4_encapcheck, &ipe4_protosw, NULL);
715#endif
716#if defined(INET6) && defined(INET)
717	(void) encap_attach_func(AF_INET6, -1,
718		ipe4_encapcheck, (struct protosw *)&ipe6_protosw, NULL);
719#endif
720}
721SYSINIT(ipe4_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ipe4_attach, NULL);
722#endif	/* IPSEC */
723