xref: /netbsd/sys/netipsec/xform_ipcomp.c (revision 6550d01e)
1 /*	$NetBSD: xform_ipcomp.c,v 1.20 2010/09/21 13:41:18 degroote Exp $	*/
2 /*	$FreeBSD: src/sys/netipsec/xform_ipcomp.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $	*/
3 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
4 
5 /*
6  * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
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  *
12  * 1. Redistributions of source code must retain the above copyright
13  *   notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *   notice, this list of conditions and the following disclaimer in the
16  *   documentation and/or other materials provided with the distribution.
17  * 3. The name of the author may not be used to endorse or promote products
18  *   derived from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: xform_ipcomp.c,v 1.20 2010/09/21 13:41:18 degroote Exp $");
34 
35 /* IP payload compression protocol (IPComp), see RFC 2393 */
36 #include "opt_inet.h"
37 #ifdef __FreeBSD__
38 #include "opt_inet6.h"
39 #endif
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/mbuf.h>
44 #include <sys/socket.h>
45 #include <sys/kernel.h>
46 #include <sys/protosw.h>
47 #include <sys/sysctl.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 
54 #include <net/route.h>
55 #include <netipsec/ipsec.h>
56 #include <netipsec/ipsec_private.h>
57 #include <netipsec/xform.h>
58 
59 #ifdef INET6
60 #include <netinet/ip6.h>
61 #include <netipsec/ipsec6.h>
62 #endif
63 
64 #include <netipsec/ipcomp.h>
65 #include <netipsec/ipcomp_var.h>
66 
67 #include <netipsec/key.h>
68 #include <netipsec/key_debug.h>
69 
70 #include <netipsec/ipsec_osdep.h>
71 
72 #include <opencrypto/cryptodev.h>
73 #include <opencrypto/deflate.h>
74 #include <opencrypto/xform.h>
75 
76 percpu_t *ipcompstat_percpu;
77 
78 int	ipcomp_enable = 1;
79 
80 #ifdef __FreeBSD__
81 SYSCTL_DECL(_net_inet_ipcomp);
82 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO,
83 	ipcomp_enable,	CTLFLAG_RW,	&ipcomp_enable,	0, "");
84 SYSCTL_STRUCT(_net_inet_ipcomp, IPSECCTL_STATS,
85 	stats,		CTLFLAG_RD,	&ipcompstat,	ipcompstat, "");
86 #endif /* __FreeBSD__ */
87 
88 static int ipcomp_input_cb(struct cryptop *crp);
89 static int ipcomp_output_cb(struct cryptop *crp);
90 
91 struct comp_algo *
92 ipcomp_algorithm_lookup(int alg)
93 {
94 	if (alg >= IPCOMP_ALG_MAX)
95 		return NULL;
96 	switch (alg) {
97 	case SADB_X_CALG_DEFLATE:
98 		return &comp_algo_deflate;
99 	}
100 	return NULL;
101 }
102 
103 /*
104  * ipcomp_init() is called when an CPI is being set up.
105  */
106 static int
107 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
108 {
109 	struct comp_algo *tcomp;
110 	struct cryptoini cric;
111 	int ses;
112 
113 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
114 	tcomp = ipcomp_algorithm_lookup(sav->alg_enc);
115 	if (tcomp == NULL) {
116 		DPRINTF(("ipcomp_init: unsupported compression algorithm %d\n",
117 			 sav->alg_comp));
118 		return EINVAL;
119 	}
120 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
121 	sav->tdb_xform = xsp;
122 	sav->tdb_compalgxform = tcomp;
123 
124 	/* Initialize crypto session */
125 	memset(&cric, 0, sizeof (cric));
126 	cric.cri_alg = sav->tdb_compalgxform->type;
127 
128 	mutex_spin_enter(&crypto_mtx);
129 	ses = crypto_newsession(&sav->tdb_cryptoid, &cric, crypto_support);
130 	mutex_spin_exit(&crypto_mtx);
131 	return ses;
132 }
133 
134 /*
135  * ipcomp_zeroize() used when IPCA is deleted
136  */
137 static int
138 ipcomp_zeroize(struct secasvar *sav)
139 {
140 	int err;
141 
142 	mutex_spin_enter(&crypto_mtx);
143 	err = crypto_freesession(sav->tdb_cryptoid);
144 	mutex_spin_exit(&crypto_mtx);
145 	sav->tdb_cryptoid = 0;
146 	return err;
147 }
148 
149 /*
150  * ipcomp_input() gets called to uncompress an input packet
151  */
152 static int
153 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
154 {
155 	struct tdb_crypto *tc;
156 	struct cryptodesc *crdc;
157 	struct cryptop *crp;
158 	int hlen = IPCOMP_HLENGTH;
159 
160 	IPSEC_SPLASSERT_SOFTNET("ipcomp_input");
161 
162 	/* Get crypto descriptors */
163 	crp = crypto_getreq(1);
164 	if (crp == NULL) {
165 		m_freem(m);
166 		DPRINTF(("ipcomp_input: no crypto descriptors\n"));
167 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
168 		return ENOBUFS;
169 	}
170 	/* Get IPsec-specific opaque pointer */
171 	tc = (struct tdb_crypto *) malloc(sizeof (*tc), M_XDATA, M_NOWAIT|M_ZERO);
172 	if (tc == NULL) {
173 		m_freem(m);
174 		crypto_freereq(crp);
175 		DPRINTF(("ipcomp_input: cannot allocate tdb_crypto\n"));
176 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
177 		return ENOBUFS;
178 	}
179 	crdc = crp->crp_desc;
180 
181 	crdc->crd_skip = skip + hlen;
182 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
183 	crdc->crd_inject = skip;
184 
185 	tc->tc_ptr = 0;
186 
187 	/* Decompression operation */
188 	crdc->crd_alg = sav->tdb_compalgxform->type;
189 
190 	/* Crypto operation descriptor */
191 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
192 	crp->crp_flags = CRYPTO_F_IMBUF;
193 	crp->crp_buf = m;
194 	crp->crp_callback = ipcomp_input_cb;
195 	crp->crp_sid = sav->tdb_cryptoid;
196 	crp->crp_opaque = tc;
197 
198 	/* These are passed as-is to the callback */
199 	tc->tc_spi = sav->spi;
200 	tc->tc_dst = sav->sah->saidx.dst;
201 	tc->tc_proto = sav->sah->saidx.proto;
202 	tc->tc_protoff = protoff;
203 	tc->tc_skip = skip;
204 
205 	return crypto_dispatch(crp);
206 }
207 
208 #ifdef INET6
209 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {		     \
210 	if (saidx->dst.sa.sa_family == AF_INET6) {			     \
211 		error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
212 	} else {							     \
213 		error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
214 	}								     \
215 } while (0)
216 #else
217 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)		     \
218 	(error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
219 #endif
220 
221 /*
222  * IPComp input callback from the crypto driver.
223  */
224 static int
225 ipcomp_input_cb(struct cryptop *crp)
226 {
227 	struct cryptodesc *crd;
228 	struct tdb_crypto *tc;
229 	int skip, protoff;
230 	struct mtag *mtag;
231 	struct mbuf *m;
232 	struct secasvar *sav;
233 	struct secasindex *saidx;
234 	int s, hlen = IPCOMP_HLENGTH, error, clen;
235 	u_int8_t nproto;
236 	void *addr;
237 	u_int16_t dport = 0;
238 	u_int16_t sport = 0;
239 #ifdef IPSEC_NAT_T
240 	struct m_tag * tag = NULL;
241 #endif
242 
243 	crd = crp->crp_desc;
244 
245 	tc = (struct tdb_crypto *) crp->crp_opaque;
246 	IPSEC_ASSERT(tc != NULL, ("ipcomp_input_cb: null opaque crypto data area!"));
247 	skip = tc->tc_skip;
248 	protoff = tc->tc_protoff;
249 	mtag = (struct mtag *) tc->tc_ptr;
250 	m = (struct mbuf *) crp->crp_buf;
251 
252 #ifdef IPSEC_NAT_T
253 	/* find the source port for NAT-T */
254 	if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) {
255 		sport = ((u_int16_t *)(tag + 1))[0];
256 		dport = ((u_int16_t *)(tag + 1))[1];
257 	}
258 #endif
259 
260 	s = splsoftnet();
261 
262 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport);
263 	if (sav == NULL) {
264 		IPCOMP_STATINC(IPCOMP_STAT_NOTDB);
265 		DPRINTF(("ipcomp_input_cb: SA expired while in crypto\n"));
266 		error = ENOBUFS;		/*XXX*/
267 		goto bad;
268 	}
269 
270 	saidx = &sav->sah->saidx;
271 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
272 		saidx->dst.sa.sa_family == AF_INET6,
273 		("ah_input_cb: unexpected protocol family %u",
274 		 saidx->dst.sa.sa_family));
275 
276 	/* Check for crypto errors */
277 	if (crp->crp_etype) {
278 		/* Reset the session ID */
279 		if (sav->tdb_cryptoid != 0)
280 			sav->tdb_cryptoid = crp->crp_sid;
281 
282 		if (crp->crp_etype == EAGAIN) {
283 			KEY_FREESAV(&sav);
284 			splx(s);
285 			return crypto_dispatch(crp);
286 		}
287 
288 		IPCOMP_STATINC(IPCOMP_STAT_NOXFORM);
289 		DPRINTF(("ipcomp_input_cb: crypto error %d\n", crp->crp_etype));
290 		error = crp->crp_etype;
291 		goto bad;
292 	}
293 	/* Shouldn't happen... */
294 	if (m == NULL) {
295 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
296 		DPRINTF(("ipcomp_input_cb: null mbuf returned from crypto\n"));
297 		error = EINVAL;
298 		goto bad;
299 	}
300 	IPCOMP_STATINC(IPCOMP_STAT_HIST + sav->alg_comp);
301 
302 	/* Update the counters */
303 	IPCOMP_STATADD(IPCOMP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen);
304 
305 
306 	clen = crp->crp_olen;		/* Length of data after processing */
307 
308 	/* Release the crypto descriptors */
309 	free(tc, M_XDATA), tc = NULL;
310 	crypto_freereq(crp), crp = NULL;
311 
312 	/* In case it's not done already, adjust the size of the mbuf chain */
313 	m->m_pkthdr.len = clen + hlen + skip;
314 
315 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == 0) {
316 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);	/*XXX*/
317 		DPRINTF(("ipcomp_input_cb: m_pullup failed\n"));
318 		error = EINVAL;				/*XXX*/
319 		goto bad;
320 	}
321 
322 	/* Keep the next protocol field */
323 	addr = (uint8_t*) mtod(m, struct ip *) + skip;
324 	nproto = ((struct ipcomp *) addr)->comp_nxt;
325 
326 	/* Remove the IPCOMP header */
327 	error = m_striphdr(m, skip, hlen);
328 	if (error) {
329 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
330 		DPRINTF(("ipcomp_input_cb: bad mbuf chain, IPCA %s/%08lx\n",
331 			 ipsec_address(&sav->sah->saidx.dst),
332 			 (u_long) ntohl(sav->spi)));
333 		goto bad;
334 	}
335 
336 	/* Restore the Next Protocol field */
337 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
338 
339 	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, NULL);
340 
341 	KEY_FREESAV(&sav);
342 	splx(s);
343 	return error;
344 bad:
345 	if (sav)
346 		KEY_FREESAV(&sav);
347 	splx(s);
348 	if (m)
349 		m_freem(m);
350 	if (tc != NULL)
351 		free(tc, M_XDATA);
352 	if (crp)
353 		crypto_freereq(crp);
354 	return error;
355 }
356 
357 /*
358  * IPComp output routine, called by ipsec[46]_process_packet()
359  */
360 static int
361 ipcomp_output(
362     struct mbuf *m,
363     struct ipsecrequest *isr,
364     struct mbuf **mp,
365     int skip,
366     int protoff
367 )
368 {
369 	struct secasvar *sav;
370 	struct comp_algo *ipcompx;
371 	int error, ralen, hlen, maxpacketsize;
372 	struct cryptodesc *crdc;
373 	struct cryptop *crp;
374 	struct tdb_crypto *tc;
375 
376 	IPSEC_SPLASSERT_SOFTNET("ipcomp_output");
377 	sav = isr->sav;
378 	IPSEC_ASSERT(sav != NULL, ("ipcomp_output: null SA"));
379 	ipcompx = sav->tdb_compalgxform;
380 	IPSEC_ASSERT(ipcompx != NULL, ("ipcomp_output: null compression xform"));
381 
382 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
383 
384     /* Don't process the packet if it is too short */
385 	if (ralen < ipcompx->minlen) {
386 		IPCOMP_STATINC(IPCOMP_STAT_MINLEN);
387 		return ipsec_process_done(m,isr);
388 	}
389 
390 	hlen = IPCOMP_HLENGTH;
391 
392 	IPCOMP_STATINC(IPCOMP_STAT_OUTPUT);
393 
394 	/* Check for maximum packet size violations. */
395 	switch (sav->sah->saidx.dst.sa.sa_family) {
396 #ifdef INET
397 	case AF_INET:
398 		maxpacketsize =  IP_MAXPACKET;
399 		break;
400 #endif /* INET */
401 #ifdef INET6
402 	case AF_INET6:
403 		maxpacketsize =  IPV6_MAXPACKET;
404 		break;
405 #endif /* INET6 */
406 	default:
407 		IPCOMP_STATINC(IPCOMP_STAT_NOPF);
408 		DPRINTF(("ipcomp_output: unknown/unsupported protocol family %d"
409 		    ", IPCA %s/%08lx\n",
410 		    sav->sah->saidx.dst.sa.sa_family,
411 		    ipsec_address(&sav->sah->saidx.dst),
412 		    (u_long) ntohl(sav->spi)));
413 		error = EPFNOSUPPORT;
414 		goto bad;
415 	}
416 	if (skip + hlen + ralen > maxpacketsize) {
417 		IPCOMP_STATINC(IPCOMP_STAT_TOOBIG);
418 		DPRINTF(("ipcomp_output: packet in IPCA %s/%08lx got too big "
419 		    "(len %u, max len %u)\n",
420 		    ipsec_address(&sav->sah->saidx.dst),
421 		    (u_long) ntohl(sav->spi),
422 		    skip + hlen + ralen, maxpacketsize));
423 		error = EMSGSIZE;
424 		goto bad;
425 	}
426 
427 	/* Update the counters */
428 	IPCOMP_STATADD(IPCOMP_STAT_OBYTES, m->m_pkthdr.len - skip);
429 
430 	m = m_clone(m);
431 	if (m == NULL) {
432 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
433 		DPRINTF(("ipcomp_output: cannot clone mbuf chain, IPCA %s/%08lx\n",
434 		    ipsec_address(&sav->sah->saidx.dst),
435 		    (u_long) ntohl(sav->spi)));
436 		error = ENOBUFS;
437 		goto bad;
438 	}
439 
440 	/* Ok now, we can pass to the crypto processing */
441 
442 	/* Get crypto descriptors */
443 	crp = crypto_getreq(1);
444 	if (crp == NULL) {
445 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
446 		DPRINTF(("ipcomp_output: failed to acquire crypto descriptor\n"));
447 		error = ENOBUFS;
448 		goto bad;
449 	}
450 	crdc = crp->crp_desc;
451 
452 	/* Compression descriptor */
453 	crdc->crd_skip = skip;
454 	crdc->crd_len = m->m_pkthdr.len - skip;
455 	crdc->crd_flags = CRD_F_COMP;
456 	crdc->crd_inject = skip;
457 
458 	/* Compression operation */
459 	crdc->crd_alg = ipcompx->type;
460 
461 	/* IPsec-specific opaque crypto info */
462 	tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
463 		M_XDATA, M_NOWAIT|M_ZERO);
464 	if (tc == NULL) {
465 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
466 		DPRINTF(("ipcomp_output: failed to allocate tdb_crypto\n"));
467 		crypto_freereq(crp);
468 		error = ENOBUFS;
469 		goto bad;
470 	}
471 
472 	tc->tc_isr = isr;
473 	tc->tc_spi = sav->spi;
474 	tc->tc_dst = sav->sah->saidx.dst;
475 	tc->tc_proto = sav->sah->saidx.proto;
476 	tc->tc_skip = skip;
477 	tc->tc_protoff = protoff;
478 
479 	/* Crypto operation descriptor */
480 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
481 	crp->crp_flags = CRYPTO_F_IMBUF;
482 	crp->crp_buf = m;
483 	crp->crp_callback = ipcomp_output_cb;
484 	crp->crp_opaque = tc;
485 	crp->crp_sid = sav->tdb_cryptoid;
486 
487 	return crypto_dispatch(crp);
488 bad:
489 	if (m)
490 		m_freem(m);
491 	return (error);
492 }
493 
494 /*
495  * IPComp output callback from the crypto driver.
496  */
497 static int
498 ipcomp_output_cb(struct cryptop *crp)
499 {
500 	struct tdb_crypto *tc;
501 	struct ipsecrequest *isr;
502 	struct secasvar *sav;
503 	struct mbuf *m, *mo;
504 	int s, error, skip, rlen, roff;
505 	u_int8_t prot;
506 	u_int16_t cpi;
507 	struct ipcomp * ipcomp;
508 
509 
510 	tc = (struct tdb_crypto *) crp->crp_opaque;
511 	IPSEC_ASSERT(tc != NULL, ("ipcomp_output_cb: null opaque data area!"));
512 	m = (struct mbuf *) crp->crp_buf;
513 	skip = tc->tc_skip;
514 	rlen = crp->crp_ilen - skip;
515 
516 	s = splsoftnet();
517 
518 	isr = tc->tc_isr;
519 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0);
520 	if (sav == NULL) {
521 		IPCOMP_STATINC(IPCOMP_STAT_NOTDB);
522 		DPRINTF(("ipcomp_output_cb: SA expired while in crypto\n"));
523 		error = ENOBUFS;		/*XXX*/
524 		goto bad;
525 	}
526 	IPSEC_ASSERT(isr->sav == sav, ("ipcomp_output_cb: SA changed\n"));
527 
528 	/* Check for crypto errors */
529 	if (crp->crp_etype) {
530 		/* Reset session ID */
531 		if (sav->tdb_cryptoid != 0)
532 			sav->tdb_cryptoid = crp->crp_sid;
533 
534 		if (crp->crp_etype == EAGAIN) {
535 			KEY_FREESAV(&sav);
536 			splx(s);
537 			return crypto_dispatch(crp);
538 		}
539 		IPCOMP_STATINC(IPCOMP_STAT_NOXFORM);
540 		DPRINTF(("ipcomp_output_cb: crypto error %d\n", crp->crp_etype));
541 		error = crp->crp_etype;
542 		goto bad;
543 	}
544 	/* Shouldn't happen... */
545 	if (m == NULL) {
546 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
547 		DPRINTF(("ipcomp_output_cb: bogus return buffer from crypto\n"));
548 		error = EINVAL;
549 		goto bad;
550 	}
551 	IPCOMP_STATINC(IPCOMP_STAT_HIST + sav->alg_comp);
552 
553 	if (rlen > crp->crp_olen) {
554 		/* Inject IPCOMP header */
555 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
556 		if (mo == NULL) {
557 			IPCOMP_STATINC(IPCOMP_STAT_WRAP);
558 			DPRINTF(("ipcomp_output: failed to inject IPCOMP header for "
559 					 "IPCA %s/%08lx\n",
560 						ipsec_address(&sav->sah->saidx.dst),
561 						(u_long) ntohl(sav->spi)));
562 			error = ENOBUFS;
563 			goto bad;
564 		}
565 		ipcomp = (struct ipcomp *)(mtod(mo, char *) + roff);
566 
567 		/* Initialize the IPCOMP header */
568 		/* XXX alignment always correct? */
569 		switch (sav->sah->saidx.dst.sa.sa_family) {
570 #ifdef INET
571 		case AF_INET:
572 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
573 			 break;
574 #endif /* INET */
575 #ifdef INET6
576 		case AF_INET6:
577 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
578 		break;
579 #endif
580 		}
581 		ipcomp->comp_flags = 0;
582 
583 		if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
584 			 cpi = sav->alg_enc;
585 		else
586 			cpi = ntohl(sav->spi) & 0xffff;
587 		ipcomp->comp_cpi = htons(cpi);
588 
589 		/* Fix Next Protocol in IPv4/IPv6 header */
590 		prot = IPPROTO_IPCOMP;
591 		m_copyback(m, tc->tc_protoff, sizeof(u_int8_t), (u_char *)&prot);
592 
593 		/* Adjust the length in the IP header */
594 		switch (sav->sah->saidx.dst.sa.sa_family) {
595 #ifdef INET
596 		case AF_INET:
597 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
598 			break;
599 #endif /* INET */
600 #ifdef INET6
601 		case AF_INET6:
602 			mtod(m, struct ip6_hdr *)->ip6_plen =
603 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
604 			break;
605 #endif /* INET6 */
606 		default:
607 			IPCOMP_STATINC(IPCOMP_STAT_NOPF);
608 			DPRINTF(("ipcomp_output: unknown/unsupported protocol "
609 			    "family %d, IPCA %s/%08lx\n",
610 			    sav->sah->saidx.dst.sa.sa_family,
611 			    ipsec_address(&sav->sah->saidx.dst),
612 			    (u_long) ntohl(sav->spi)));
613 			error = EPFNOSUPPORT;
614 			goto bad;
615 		}
616 	} else {
617 		/* compression was useless, we have lost time */
618 		IPCOMP_STATINC(IPCOMP_STAT_USELESS);
619 		DPRINTF(("ipcomp_output_cb: compression was useless : initial size was %d"
620 				   	"and compressed size is %d\n", rlen, crp->crp_olen));
621 	}
622 
623 
624 	/* Release the crypto descriptor */
625 	free(tc, M_XDATA);
626 	crypto_freereq(crp);
627 
628 	/* NB: m is reclaimed by ipsec_process_done. */
629 	error = ipsec_process_done(m, isr);
630 	KEY_FREESAV(&sav);
631 	splx(s);
632 	return error;
633 bad:
634 	if (sav)
635 		KEY_FREESAV(&sav);
636 	splx(s);
637 	if (m)
638 		m_freem(m);
639 	free(tc, M_XDATA);
640 	crypto_freereq(crp);
641 	return error;
642 }
643 
644 static struct xformsw ipcomp_xformsw = {
645 	XF_IPCOMP,		XFT_COMP,		"IPcomp",
646 	ipcomp_init,		ipcomp_zeroize,		ipcomp_input,
647 	ipcomp_output,
648 	NULL,
649 };
650 
651 INITFN void
652 ipcomp_attach(void)
653 {
654 	ipcompstat_percpu = percpu_alloc(sizeof(uint64_t) * IPCOMP_NSTATS);
655 	xform_register(&ipcomp_xformsw);
656 }
657 
658 #ifdef __FreeBSD__
659 SYSINIT(ipcomp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, ipcomp_attach, NULL)
660 #endif /* __FreeBSD__ */
661