[apple/xnu.git] / bsd / netinet6 / ipcomp_input.c

/*	$FreeBSD: src/sys/netinet6/ipcomp_input.c,v 1.1.2.2 2001/07/03 11:01:54 ume Exp $	*/
/*	$KAME: ipcomp_input.c,v 1.25 2001/03/01 09:12:09 itojun Exp $	*/

/*
 * Copyright (C) 1999 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * RFC2393 IP payload compression protocol (IPComp).
 */


#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/route.h>
#include <libkern/zlib.h>
#include <kern/cpu_number.h>
#include <kern/locks.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_ecn.h>
#include <netinet/kpi_ipfilter_var.h>

#if INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#endif
#include <netinet6/ipcomp.h>
#if INET6
#include <netinet6/ipcomp6.h>
#endif

#include <netinet6/ipsec.h>
#if INET6
#include <netinet6/ipsec6.h>
#endif
#include <netkey/key.h>
#include <netkey/keydb.h>

#include <net/net_osdep.h>
#include <mach/sdt.h>

#define IPLEN_FLIPPED

void
ipcomp4_input(struct mbuf *m, int off)
{
	struct mbuf *md;
	struct ip *ip;
	struct ipcomp *ipcomp;
	const struct ipcomp_algorithm *algo;
	u_int16_t cpi;	/* host order */
	u_int16_t nxt;
	size_t hlen;
	int error;
	size_t newlen, olen;
	struct secasvar *sav = NULL;


	if (m->m_pkthdr.len < off + sizeof(struct ipcomp)) {
		ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
		    "(packet too short)\n"));
		IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
		goto fail;
	}

	md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
	if (!md) {
		m = NULL;	/*already freed*/
		ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
		    "(pulldown failure)\n"));
		IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
		goto fail;
	}
	ipcomp = mtod(md, struct ipcomp *);
	ip = mtod(m, struct ip *);
	nxt = ipcomp->comp_nxt;
#ifdef _IP_VHL
	hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#else
	hlen = ip->ip_hl << 2;
#endif

	cpi = ntohs(ipcomp->comp_cpi);

	if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
		sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src,
			(caddr_t)&ip->ip_dst, IPPROTO_IPCOMP, htonl(cpi));
		if (sav != NULL
		 && (sav->state == SADB_SASTATE_MATURE
		  || sav->state == SADB_SASTATE_DYING)) {
			cpi = sav->alg_enc;	/*XXX*/
			/* other parameters to look at? */
		}
	}
	algo = ipcomp_algorithm_lookup(cpi);
	if (!algo) {
		ipseclog((LOG_WARNING, "IPv4 IPComp input: unknown cpi %u\n",
			cpi));
		IPSEC_STAT_INCREMENT(ipsecstat.in_nosa);
		goto fail;
	}

	/* chop ipcomp header */
	ipcomp = NULL;
	md->m_data += sizeof(struct ipcomp);
	md->m_len -= sizeof(struct ipcomp);
	m->m_pkthdr.len -= sizeof(struct ipcomp);
#ifdef IPLEN_FLIPPED
	ip->ip_len -= sizeof(struct ipcomp);
#else
	ip->ip_len = htons(ntohs(ip->ip_len) - sizeof(struct ipcomp));
#endif

	olen = m->m_pkthdr.len;
	newlen = m->m_pkthdr.len - off;
	error = (*algo->decompress)(m, m->m_next, &newlen);
	if (error != 0) {
		if (error == EINVAL) {
			IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
		} else if (error == ENOBUFS)
			IPSEC_STAT_INCREMENT(ipsecstat.in_nomem);
		m = NULL;
		goto fail;
	}
	IPSEC_STAT_INCREMENT(ipsecstat.in_comphist[cpi]);

	/*
	 * returning decompressed packet onto icmp is meaningless.
	 * mark it decrypted to prevent icmp from attaching original packet.
	 */
	m->m_flags |= M_DECRYPTED;

	m->m_pkthdr.len = off + newlen;
	ip = mtod(m, struct ip *);
    {
	size_t len;
#ifdef IPLEN_FLIPPED
	len = ip->ip_len;
#else
	len = ntohs(ip->ip_len);
#endif
	/*
	 * be careful about underflow.  also, do not assign exact value
	 * as ip_len is manipulated differently on *BSDs.
	 */
	len += m->m_pkthdr.len;
	len -= olen;
	if (len & ~0xffff) {
		/* packet too big after decompress */
		IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
		goto fail;
	}
#ifdef IPLEN_FLIPPED
	ip->ip_len = len & 0xffff;
#else
	ip->ip_len = htons(len & 0xffff);
#endif
	ip->ip_p = nxt;
    }

	if (sav) {
		key_sa_recordxfer(sav, m);
		if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
			IPSEC_STAT_INCREMENT(ipsecstat.in_nomem);
			goto fail;
		}
		key_freesav(sav, KEY_SADB_UNLOCKED);
		sav = NULL;
	}

	if (nxt != IPPROTO_DONE) {
		if ((ip_protox[nxt]->pr_flags & PR_LASTHDR) != 0 &&
		    ipsec4_in_reject(m, NULL)) {
			IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
			goto fail;
		}

		DTRACE_IP6(receive, struct mbuf *, m, struct inpcb *, NULL,
                        struct ip *, ip, struct ifnet *, m->m_pkthdr.rcvif,
                        struct ip *, ip, struct ip6_hdr *, NULL);

		ip_proto_dispatch_in(m, off, nxt, 0);
	} else
		m_freem(m);
	m = NULL;

	IPSEC_STAT_INCREMENT(ipsecstat.in_success);
	return;

fail:
	if (sav)
		key_freesav(sav, KEY_SADB_UNLOCKED);

	if (m)
		m_freem(m);
	return;
}

#if INET6
int
ipcomp6_input(struct mbuf **mp, int *offp, int proto)
{
#pragma unused(proto)
	struct mbuf *m, *md;
	int off;
	struct ip6_hdr *ip6;
	struct ipcomp *ipcomp;
	const struct ipcomp_algorithm *algo;
	u_int16_t cpi;	/* host order */
	u_int16_t nxt;
	int error;
	size_t newlen;
	struct secasvar *sav = NULL;
	char *prvnxtp;

	m = *mp;
	off = *offp;

	md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
	if (!md) {
		m = NULL;	/*already freed*/
		ipseclog((LOG_DEBUG, "IPv6 IPComp input: assumption failed "
		    "(pulldown failure)\n"));
		IPSEC_STAT_INCREMENT(ipsec6stat.in_inval);
		goto fail;
	}
	ipcomp = mtod(md, struct ipcomp *);
	ip6 = mtod(m, struct ip6_hdr *);
	nxt = ipcomp->comp_nxt;

	cpi = ntohs(ipcomp->comp_cpi);

	if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
		sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src,
			(caddr_t)&ip6->ip6_dst, IPPROTO_IPCOMP, htonl(cpi));
		if (sav != NULL
		 && (sav->state == SADB_SASTATE_MATURE
		  || sav->state == SADB_SASTATE_DYING)) {
			cpi = sav->alg_enc;	/*XXX*/
			/* other parameters to look at? */
		}
	}
	algo = ipcomp_algorithm_lookup(cpi);
	if (!algo) {
		ipseclog((LOG_WARNING, "IPv6 IPComp input: unknown cpi %u; "
			"dropping the packet for simplicity\n", cpi));
		IPSEC_STAT_INCREMENT(ipsec6stat.in_nosa);
		goto fail;
	}

	/* chop ipcomp header */
	ipcomp = NULL;
	md->m_data += sizeof(struct ipcomp);
	md->m_len -= sizeof(struct ipcomp);
	m->m_pkthdr.len -= sizeof(struct ipcomp);

	newlen = m->m_pkthdr.len - off;
	error = (*algo->decompress)(m, md, &newlen);
	if (error != 0) {
		if (error == EINVAL) {
			IPSEC_STAT_INCREMENT(ipsec6stat.in_inval);
		} else if (error == ENOBUFS)
			IPSEC_STAT_INCREMENT(ipsec6stat.in_nomem);
		m = NULL;
		goto fail;
	}
	IPSEC_STAT_INCREMENT(ipsec6stat.in_comphist[cpi]);
	m->m_pkthdr.len = off + newlen;

	/*
	 * returning decompressed packet onto icmp is meaningless.
	 * mark it decrypted to prevent icmp from attaching original packet.
	 */
	m->m_flags |= M_DECRYPTED;

	/* update next header field */
	prvnxtp = ip6_get_prevhdr(m, off);
	*prvnxtp = nxt;

	/*
	 * no need to adjust payload length, as all the IPv6 protocols
	 * look at m->m_pkthdr.len
	 */

	if (sav) {
		key_sa_recordxfer(sav, m);
		if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
			IPSEC_STAT_INCREMENT(ipsec6stat.in_nomem);
			goto fail;
		}
		key_freesav(sav, KEY_SADB_UNLOCKED);
		sav = NULL;
	}
	*offp = off;
	*mp = m;
	IPSEC_STAT_INCREMENT(ipsec6stat.in_success);
	return nxt;

fail:
	if (m)
		m_freem(m);
	if (sav)
		key_freesav(sav, KEY_SADB_UNLOCKED);
	return IPPROTO_DONE;
}
#endif /* INET6 */
Commit	Line	Data
9bccf70c A	1	/* $FreeBSD: src/sys/netinet6/ipcomp_input.c,v 1.1.2.2 2001/07/03 11:01:54 ume Exp $ */
9bccf70c A	2	/* $KAME: ipcomp_input.c,v 1.25 2001/03/01 09:12:09 itojun Exp $ */
1c79356b A	3
	4	/*
	5	* Copyright (C) 1999 WIDE Project.
	6	* All rights reserved.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. Neither the name of the project nor the names of its contributors
	17	* may be used to endorse or promote products derived from this software
	18	* without specific prior written permission.
	19	*
	20	* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
	21	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
	24	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	* SUCH DAMAGE.
	31	*/
	32
	33	/*
	34	* RFC2393 IP payload compression protocol (IPComp).
	35	*/
	36
1c79356b A	37
	38	#include <sys/param.h>
	39	#include <sys/systm.h>
	40	#include <sys/malloc.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/time.h>
	47	#include <sys/kernel.h>
	48	#include <sys/syslog.h>
	49
	50	#include <net/if.h>
	51	#include <net/route.h>
2d21ac55	52	#include <libkern/zlib.h>
1c79356b	53	#include <kern/cpu_number.h>
91447636	54	#include <kern/locks.h>
1c79356b A	55
	56	#include <netinet/in.h>
	57	#include <netinet/in_systm.h>
	58	#include <netinet/in_var.h>
	59	#include <netinet/ip.h>
	60	#include <netinet/ip_var.h>
	61	#include <netinet/ip_ecn.h>
2d21ac55	62	#include <netinet/kpi_ipfilter_var.h>
1c79356b A	63
	64	#if INET6
	65	#include <netinet/ip6.h>
	66	#include <netinet6/ip6_var.h>
	67	#endif
	68	#include <netinet6/ipcomp.h>
9bccf70c A	69	#if INET6
	70	#include <netinet6/ipcomp6.h>
	71	#endif
1c79356b A	72
1c79356b A	73	#include <netinet6/ipsec.h>
9bccf70c A	74	#if INET6
	75	#include <netinet6/ipsec6.h>
	76	#endif
1c79356b A	77	#include <netkey/key.h>
1c79356b A	78	#include <netkey/keydb.h>
1c79356b A	79
1c79356b A	80	#include <net/net_osdep.h>
6d2010ae	81	#include <mach/sdt.h>
1c79356b A	82
	83	#define IPLEN_FLIPPED
	84
1c79356b A	85	void
	86	ipcomp4_input(struct mbuf *m, int off)
	87	{
9bccf70c	88	struct mbuf *md;
1c79356b A	89	struct ip *ip;
1c79356b A	90	struct ipcomp *ipcomp;
9bccf70c	91	const struct ipcomp_algorithm *algo;
1c79356b A	92	u_int16_t cpi; /* host order */
	93	u_int16_t nxt;
	94	size_t hlen;
	95	int error;
	96	size_t newlen, olen;
	97	struct secasvar *sav = NULL;
	98
	99
9bccf70c	100	if (m->m_pkthdr.len < off + sizeof(struct ipcomp)) {
1c79356b	101	ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
9bccf70c	102	"(packet too short)\n"));
2d21ac55	103	IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
1c79356b A	104	goto fail;
1c79356b A	105	}
1c79356b	106
9bccf70c	107	md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
cf7d32b8	108	if (!md) {
9bccf70c A	109	m = NULL; /already freed/
	110	ipseclog((LOG_DEBUG, "IPv4 IPComp input: assumption failed "
	111	"(pulldown failure)\n"));
2d21ac55	112	IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
9bccf70c A	113	goto fail;
	114	}
	115	ipcomp = mtod(md, struct ipcomp *);
1c79356b	116	ip = mtod(m, struct ip *);
1c79356b A	117	nxt = ipcomp->comp_nxt;
	118	#ifdef _IP_VHL
	119	hlen = IP_VHL_HL(ip->ip_vhl) << 2;
	120	#else
	121	hlen = ip->ip_hl << 2;
	122	#endif
	123
	124	cpi = ntohs(ipcomp->comp_cpi);
	125
	126	if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
	127	sav = key_allocsa(AF_INET, (caddr_t)&ip->ip_src,
	128	(caddr_t)&ip->ip_dst, IPPROTO_IPCOMP, htonl(cpi));
	129	if (sav != NULL
	130	&& (sav->state == SADB_SASTATE_MATURE
	131	\|\| sav->state == SADB_SASTATE_DYING)) {
	132	cpi = sav->alg_enc; /XXX/
	133	/* other parameters to look at? */
	134	}
	135	}
9bccf70c	136	algo = ipcomp_algorithm_lookup(cpi);
1c79356b A	137	if (!algo) {
	138	ipseclog((LOG_WARNING, "IPv4 IPComp input: unknown cpi %u\n",
	139	cpi));
2d21ac55	140	IPSEC_STAT_INCREMENT(ipsecstat.in_nosa);
1c79356b A	141	goto fail;
	142	}
	143
	144	/* chop ipcomp header */
	145	ipcomp = NULL;
9bccf70c A	146	md->m_data += sizeof(struct ipcomp);
9bccf70c A	147	md->m_len -= sizeof(struct ipcomp);
1c79356b A	148	m->m_pkthdr.len -= sizeof(struct ipcomp);
	149	#ifdef IPLEN_FLIPPED
	150	ip->ip_len -= sizeof(struct ipcomp);
	151	#else
	152	ip->ip_len = htons(ntohs(ip->ip_len) - sizeof(struct ipcomp));
	153	#endif
	154
	155	olen = m->m_pkthdr.len;
	156	newlen = m->m_pkthdr.len - off;
	157	error = (*algo->decompress)(m, m->m_next, &newlen);
	158	if (error != 0) {
2d21ac55 A	159	if (error == EINVAL) {
	160	IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
	161	} else if (error == ENOBUFS)
	162	IPSEC_STAT_INCREMENT(ipsecstat.in_nomem);
1c79356b A	163	m = NULL;
	164	goto fail;
	165	}
2d21ac55	166	IPSEC_STAT_INCREMENT(ipsecstat.in_comphist[cpi]);
1c79356b A	167
	168	/*
	169	* returning decompressed packet onto icmp is meaningless.
	170	* mark it decrypted to prevent icmp from attaching original packet.
	171	*/
	172	m->m_flags \|= M_DECRYPTED;
	173
	174	m->m_pkthdr.len = off + newlen;
	175	ip = mtod(m, struct ip *);
	176	{
	177	size_t len;
	178	#ifdef IPLEN_FLIPPED
	179	len = ip->ip_len;
	180	#else
	181	len = ntohs(ip->ip_len);
	182	#endif
	183	/*
	184	* be careful about underflow. also, do not assign exact value
	185	* as ip_len is manipulated differently on *BSDs.
	186	*/
	187	len += m->m_pkthdr.len;
	188	len -= olen;
	189	if (len & ~0xffff) {
	190	/* packet too big after decompress */
2d21ac55	191	IPSEC_STAT_INCREMENT(ipsecstat.in_inval);
1c79356b A	192	goto fail;
	193	}
	194	#ifdef IPLEN_FLIPPED
	195	ip->ip_len = len & 0xffff;
	196	#else
	197	ip->ip_len = htons(len & 0xffff);
	198	#endif
	199	ip->ip_p = nxt;
	200	}
	201
	202	if (sav) {
	203	key_sa_recordxfer(sav, m);
9bccf70c	204	if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
2d21ac55	205	IPSEC_STAT_INCREMENT(ipsecstat.in_nomem);
9bccf70c A	206	goto fail;
9bccf70c A	207	}
2d21ac55	208	key_freesav(sav, KEY_SADB_UNLOCKED);
1c79356b A	209	sav = NULL;
	210	}
	211
9bccf70c A	212	if (nxt != IPPROTO_DONE) {
	213	if ((ip_protox[nxt]->pr_flags & PR_LASTHDR) != 0 &&
	214	ipsec4_in_reject(m, NULL)) {
2d21ac55	215	IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
9bccf70c A	216	goto fail;
9bccf70c A	217	}
6d2010ae A	218
	219	DTRACE_IP6(receive, struct mbuf , m, struct inpcb , NULL,
	220	struct ip , ip, struct ifnet , m->m_pkthdr.rcvif,
	221	struct ip , ip, struct ip6_hdr , NULL);
	222
91447636	223	ip_proto_dispatch_in(m, off, nxt, 0);
9bccf70c	224	} else
1c79356b A	225	m_freem(m);
	226	m = NULL;
	227
2d21ac55	228	IPSEC_STAT_INCREMENT(ipsecstat.in_success);
1c79356b A	229	return;
	230
	231	fail:
	232	if (sav)
2d21ac55	233	key_freesav(sav, KEY_SADB_UNLOCKED);
91447636	234
1c79356b A	235	if (m)
	236	m_freem(m);
	237	return;
	238	}
1c79356b A	239
	240	#if INET6
	241	int
6d2010ae	242	ipcomp6_input(struct mbuf *mp, int offp, int proto)
1c79356b	243	{
6d2010ae	244	#pragma unused(proto)
1c79356b A	245	struct mbuf m, md;
	246	int off;
	247	struct ip6_hdr *ip6;
1c79356b	248	struct ipcomp *ipcomp;
9bccf70c	249	const struct ipcomp_algorithm *algo;
1c79356b A	250	u_int16_t cpi; /* host order */
	251	u_int16_t nxt;
	252	int error;
	253	size_t newlen;
	254	struct secasvar *sav = NULL;
9bccf70c	255	char *prvnxtp;
1c79356b A	256
	257	m = *mp;
	258	off = *offp;
	259
9bccf70c	260	md = m_pulldown(m, off, sizeof(*ipcomp), NULL);
cf7d32b8	261	if (!md) {
9bccf70c A	262	m = NULL; /already freed/
	263	ipseclog((LOG_DEBUG, "IPv6 IPComp input: assumption failed "
	264	"(pulldown failure)\n"));
2d21ac55	265	IPSEC_STAT_INCREMENT(ipsec6stat.in_inval);
1c79356b A	266	goto fail;
1c79356b A	267	}
9bccf70c	268	ipcomp = mtod(md, struct ipcomp *);
1c79356b	269	ip6 = mtod(m, struct ip6_hdr *);
1c79356b	270	nxt = ipcomp->comp_nxt;
9bccf70c	271
1c79356b A	272	cpi = ntohs(ipcomp->comp_cpi);
	273
	274	if (cpi >= IPCOMP_CPI_NEGOTIATE_MIN) {
	275	sav = key_allocsa(AF_INET6, (caddr_t)&ip6->ip6_src,
	276	(caddr_t)&ip6->ip6_dst, IPPROTO_IPCOMP, htonl(cpi));
	277	if (sav != NULL
	278	&& (sav->state == SADB_SASTATE_MATURE
	279	\|\| sav->state == SADB_SASTATE_DYING)) {
	280	cpi = sav->alg_enc; /XXX/
	281	/* other parameters to look at? */
	282	}
	283	}
9bccf70c	284	algo = ipcomp_algorithm_lookup(cpi);
1c79356b A	285	if (!algo) {
	286	ipseclog((LOG_WARNING, "IPv6 IPComp input: unknown cpi %u; "
	287	"dropping the packet for simplicity\n", cpi));
2d21ac55	288	IPSEC_STAT_INCREMENT(ipsec6stat.in_nosa);
1c79356b A	289	goto fail;
	290	}
	291
9bccf70c A	292	/* chop ipcomp header */
	293	ipcomp = NULL;
	294	md->m_data += sizeof(struct ipcomp);
	295	md->m_len -= sizeof(struct ipcomp);
	296	m->m_pkthdr.len -= sizeof(struct ipcomp);
	297
	298	newlen = m->m_pkthdr.len - off;
1c79356b A	299	error = (*algo->decompress)(m, md, &newlen);
1c79356b A	300	if (error != 0) {
2d21ac55 A	301	if (error == EINVAL) {
	302	IPSEC_STAT_INCREMENT(ipsec6stat.in_inval);
	303	} else if (error == ENOBUFS)
	304	IPSEC_STAT_INCREMENT(ipsec6stat.in_nomem);
1c79356b A	305	m = NULL;
	306	goto fail;
	307	}
2d21ac55	308	IPSEC_STAT_INCREMENT(ipsec6stat.in_comphist[cpi]);
9bccf70c	309	m->m_pkthdr.len = off + newlen;
1c79356b A	310
	311	/*
	312	* returning decompressed packet onto icmp is meaningless.
	313	* mark it decrypted to prevent icmp from attaching original packet.
	314	*/
	315	m->m_flags \|= M_DECRYPTED;
	316
9bccf70c	317	/* update next header field */
1c79356b A	318	prvnxtp = ip6_get_prevhdr(m, off);
1c79356b A	319	*prvnxtp = nxt;
1c79356b	320
9bccf70c A	321	/*
	322	* no need to adjust payload length, as all the IPv6 protocols
	323	* look at m->m_pkthdr.len
	324	*/
1c79356b A	325
	326	if (sav) {
	327	key_sa_recordxfer(sav, m);
9bccf70c	328	if (ipsec_addhist(m, IPPROTO_IPCOMP, (u_int32_t)cpi) != 0) {
2d21ac55	329	IPSEC_STAT_INCREMENT(ipsec6stat.in_nomem);
9bccf70c A	330	goto fail;
9bccf70c A	331	}
2d21ac55	332	key_freesav(sav, KEY_SADB_UNLOCKED);
1c79356b A	333	sav = NULL;
	334	}
	335	*offp = off;
	336	*mp = m;
2d21ac55	337	IPSEC_STAT_INCREMENT(ipsec6stat.in_success);
1c79356b A	338	return nxt;
	339
	340	fail:
	341	if (m)
	342	m_freem(m);
	343	if (sav)
2d21ac55	344	key_freesav(sav, KEY_SADB_UNLOCKED);
1c79356b A	345	return IPPROTO_DONE;
	346	}
	347	#endif /* INET6 */