xref: /netbsd-src/sys/netipsec/xform_ipcomp.c (revision a536ee5124e62c9a0051a252f7833dc8f50f44c9)
1 /*	$NetBSD: xform_ipcomp.c,v 1.29 2012/01/25 20:31:23 drochner 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 1.29 2012/01/25 20:31:23 drochner 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 #include <sys/socketvar.h> /* for softnet_lock */
49 
50 #include <netinet/in.h>
51 #include <netinet/in_systm.h>
52 #include <netinet/ip.h>
53 #include <netinet/ip_var.h>
54 
55 #include <net/route.h>
56 #include <netipsec/ipsec.h>
57 #include <netipsec/ipsec_private.h>
58 #include <netipsec/xform.h>
59 
60 #ifdef INET6
61 #include <netinet/ip6.h>
62 #include <netipsec/ipsec6.h>
63 #endif
64 
65 #include <netipsec/ipcomp.h>
66 #include <netipsec/ipcomp_var.h>
67 
68 #include <netipsec/key.h>
69 #include <netipsec/key_debug.h>
70 
71 #include <netipsec/ipsec_osdep.h>
72 
73 #include <opencrypto/cryptodev.h>
74 #include <opencrypto/deflate.h>
75 #include <opencrypto/xform.h>
76 
77 percpu_t *ipcompstat_percpu;
78 
79 int	ipcomp_enable = 1;
80 
81 #ifdef __FreeBSD__
82 SYSCTL_DECL(_net_inet_ipcomp);
83 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO,
84 	ipcomp_enable,	CTLFLAG_RW,	&ipcomp_enable,	0, "");
85 SYSCTL_STRUCT(_net_inet_ipcomp, IPSECCTL_STATS,
86 	stats,		CTLFLAG_RD,	&ipcompstat,	ipcompstat, "");
87 #endif /* __FreeBSD__ */
88 
89 static int ipcomp_input_cb(struct cryptop *crp);
90 static int ipcomp_output_cb(struct cryptop *crp);
91 
92 const struct comp_algo *
93 ipcomp_algorithm_lookup(int alg)
94 {
95 	if (alg >= IPCOMP_ALG_MAX)
96 		return NULL;
97 	switch (alg) {
98 	case SADB_X_CALG_DEFLATE:
99 		return &comp_algo_deflate_nogrow;
100 	}
101 	return NULL;
102 }
103 
104 /*
105  * ipcomp_init() is called when an CPI is being set up.
106  */
107 static int
108 ipcomp_init(struct secasvar *sav, const struct xformsw *xsp)
109 {
110 	const struct comp_algo *tcomp;
111 	struct cryptoini cric;
112 	int ses;
113 
114 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
115 	tcomp = ipcomp_algorithm_lookup(sav->alg_enc);
116 	if (tcomp == NULL) {
117 		DPRINTF(("ipcomp_init: unsupported compression algorithm %d\n",
118 			 sav->alg_comp));
119 		return EINVAL;
120 	}
121 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
122 	sav->tdb_xform = xsp;
123 	sav->tdb_compalgxform = tcomp;
124 
125 	/* Initialize crypto session */
126 	memset(&cric, 0, sizeof (cric));
127 	cric.cri_alg = sav->tdb_compalgxform->type;
128 
129 	ses = crypto_newsession(&sav->tdb_cryptoid, &cric, crypto_support);
130 	return ses;
131 }
132 
133 /*
134  * ipcomp_zeroize() used when IPCA is deleted
135  */
136 static int
137 ipcomp_zeroize(struct secasvar *sav)
138 {
139 	int err;
140 
141 	err = crypto_freesession(sav->tdb_cryptoid);
142 	sav->tdb_cryptoid = 0;
143 	return err;
144 }
145 
146 /*
147  * ipcomp_input() gets called to uncompress an input packet
148  */
149 static int
150 ipcomp_input(struct mbuf *m, const struct secasvar *sav, int skip, int protoff)
151 {
152 	struct tdb_crypto *tc;
153 	struct cryptodesc *crdc;
154 	struct cryptop *crp;
155 	int error, hlen = IPCOMP_HLENGTH;
156 
157 	IPSEC_SPLASSERT_SOFTNET("ipcomp_input");
158 
159 	/* Get crypto descriptors */
160 	crp = crypto_getreq(1);
161 	if (crp == NULL) {
162 		m_freem(m);
163 		DPRINTF(("ipcomp_input: no crypto descriptors\n"));
164 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
165 		return ENOBUFS;
166 	}
167 	/* Get IPsec-specific opaque pointer */
168 	tc = (struct tdb_crypto *) malloc(sizeof (*tc), M_XDATA, M_NOWAIT|M_ZERO);
169 	if (tc == NULL) {
170 		m_freem(m);
171 		crypto_freereq(crp);
172 		DPRINTF(("ipcomp_input: cannot allocate tdb_crypto\n"));
173 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
174 		return ENOBUFS;
175 	}
176 
177 	error = m_makewritable(&m, 0, m->m_pkthdr.len, M_NOWAIT);
178 	if (error) {
179 		DPRINTF(("ipcomp_input: m_makewritable failed\n"));
180 		m_freem(m);
181 		free(tc, M_XDATA);
182 		crypto_freereq(crp);
183 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
184 		return error;
185 	}
186 
187 	crdc = crp->crp_desc;
188 
189 	crdc->crd_skip = skip + hlen;
190 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
191 	crdc->crd_inject = 0; /* unused */
192 
193 	tc->tc_ptr = 0;
194 
195 	/* Decompression operation */
196 	crdc->crd_alg = sav->tdb_compalgxform->type;
197 
198 	/* Crypto operation descriptor */
199 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
200 	crp->crp_olen = MCLBYTES; /* hint to decompression code */
201 	crp->crp_flags = CRYPTO_F_IMBUF;
202 	crp->crp_buf = m;
203 	crp->crp_callback = ipcomp_input_cb;
204 	crp->crp_sid = sav->tdb_cryptoid;
205 	crp->crp_opaque = tc;
206 
207 	/* These are passed as-is to the callback */
208 	tc->tc_spi = sav->spi;
209 	tc->tc_dst = sav->sah->saidx.dst;
210 	tc->tc_proto = sav->sah->saidx.proto;
211 	tc->tc_protoff = protoff;
212 	tc->tc_skip = skip;
213 
214 	return crypto_dispatch(crp);
215 }
216 
217 #ifdef INET6
218 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {		     \
219 	if (saidx->dst.sa.sa_family == AF_INET6) {			     \
220 		error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
221 	} else {							     \
222 		error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
223 	}								     \
224 } while (0)
225 #else
226 #define	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)		     \
227 	(error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
228 #endif
229 
230 /*
231  * IPComp input callback from the crypto driver.
232  */
233 static int
234 ipcomp_input_cb(struct cryptop *crp)
235 {
236 	struct cryptodesc *crd;
237 	struct tdb_crypto *tc;
238 	int skip, protoff;
239 	struct mtag *mtag;
240 	struct mbuf *m;
241 	struct secasvar *sav;
242 	struct secasindex *saidx;
243 	int s, hlen = IPCOMP_HLENGTH, error, clen;
244 	u_int8_t nproto;
245 	void *addr;
246 	u_int16_t dport = 0;
247 	u_int16_t sport = 0;
248 #ifdef IPSEC_NAT_T
249 	struct m_tag * tag = NULL;
250 #endif
251 
252 	crd = crp->crp_desc;
253 
254 	tc = (struct tdb_crypto *) crp->crp_opaque;
255 	IPSEC_ASSERT(tc != NULL, ("ipcomp_input_cb: null opaque crypto data area!"));
256 	skip = tc->tc_skip;
257 	protoff = tc->tc_protoff;
258 	mtag = (struct mtag *) tc->tc_ptr;
259 	m = (struct mbuf *) crp->crp_buf;
260 
261 #ifdef IPSEC_NAT_T
262 	/* find the source port for NAT-T */
263 	if ((tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL))) {
264 		sport = ((u_int16_t *)(tag + 1))[0];
265 		dport = ((u_int16_t *)(tag + 1))[1];
266 	}
267 #endif
268 
269 	s = splsoftnet();
270 	mutex_enter(softnet_lock);
271 
272 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, sport, dport);
273 	if (sav == NULL) {
274 		IPCOMP_STATINC(IPCOMP_STAT_NOTDB);
275 		DPRINTF(("ipcomp_input_cb: SA expired while in crypto\n"));
276 		error = ENOBUFS;		/*XXX*/
277 		goto bad;
278 	}
279 
280 	saidx = &sav->sah->saidx;
281 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
282 		saidx->dst.sa.sa_family == AF_INET6,
283 		("ipcomp_input_cb: unexpected protocol family %u",
284 		 saidx->dst.sa.sa_family));
285 
286 	/* Check for crypto errors */
287 	if (crp->crp_etype) {
288 		/* Reset the session ID */
289 		if (sav->tdb_cryptoid != 0)
290 			sav->tdb_cryptoid = crp->crp_sid;
291 
292 		if (crp->crp_etype == EAGAIN) {
293 			KEY_FREESAV(&sav);
294 			mutex_exit(softnet_lock);
295 			splx(s);
296 			return crypto_dispatch(crp);
297 		}
298 
299 		IPCOMP_STATINC(IPCOMP_STAT_NOXFORM);
300 		DPRINTF(("ipcomp_input_cb: crypto error %d\n", crp->crp_etype));
301 		error = crp->crp_etype;
302 		goto bad;
303 	}
304 	/* Shouldn't happen... */
305 	if (m == NULL) {
306 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
307 		DPRINTF(("ipcomp_input_cb: null mbuf returned from crypto\n"));
308 		error = EINVAL;
309 		goto bad;
310 	}
311 	IPCOMP_STATINC(IPCOMP_STAT_HIST + sav->alg_comp);
312 
313 	/* Update the counters */
314 	IPCOMP_STATADD(IPCOMP_STAT_IBYTES, m->m_pkthdr.len - skip - hlen);
315 
316 
317 	clen = crp->crp_olen;		/* Length of data after processing */
318 
319 	/* Release the crypto descriptors */
320 	free(tc, M_XDATA), tc = NULL;
321 	crypto_freereq(crp), crp = NULL;
322 
323 	/* In case it's not done already, adjust the size of the mbuf chain */
324 	m->m_pkthdr.len = clen + hlen + skip;
325 
326 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == 0) {
327 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);	/*XXX*/
328 		DPRINTF(("ipcomp_input_cb: m_pullup failed\n"));
329 		error = EINVAL;				/*XXX*/
330 		goto bad;
331 	}
332 
333 	/* Keep the next protocol field */
334 	addr = (uint8_t*) mtod(m, struct ip *) + skip;
335 	nproto = ((struct ipcomp *) addr)->comp_nxt;
336 	if (nproto == IPPROTO_IPCOMP || nproto == IPPROTO_AH || nproto == IPPROTO_ESP) {
337 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
338 		DPRINTF(("ipcomp_input_cb: nested ipcomp, IPCA %s/%08lx\n",
339 			 ipsec_address(&sav->sah->saidx.dst),
340 			 (u_long) ntohl(sav->spi)));
341 		error = EINVAL;
342 		goto bad;
343 	}
344 
345 	/* Remove the IPCOMP header */
346 	error = m_striphdr(m, skip, hlen);
347 	if (error) {
348 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
349 		DPRINTF(("ipcomp_input_cb: bad mbuf chain, IPCA %s/%08lx\n",
350 			 ipsec_address(&sav->sah->saidx.dst),
351 			 (u_long) ntohl(sav->spi)));
352 		goto bad;
353 	}
354 
355 	/* Restore the Next Protocol field */
356 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
357 
358 	IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, NULL);
359 
360 	KEY_FREESAV(&sav);
361 	mutex_exit(softnet_lock);
362 	splx(s);
363 	return error;
364 bad:
365 	if (sav)
366 		KEY_FREESAV(&sav);
367 	mutex_exit(softnet_lock);
368 	splx(s);
369 	if (m)
370 		m_freem(m);
371 	if (tc != NULL)
372 		free(tc, M_XDATA);
373 	if (crp)
374 		crypto_freereq(crp);
375 	return error;
376 }
377 
378 /*
379  * IPComp output routine, called by ipsec[46]_process_packet()
380  */
381 static int
382 ipcomp_output(
383     struct mbuf *m,
384     struct ipsecrequest *isr,
385     struct mbuf **mp,
386     int skip,
387     int protoff
388 )
389 {
390 	const struct secasvar *sav;
391 	const struct comp_algo *ipcompx;
392 	int error, ralen, hlen, maxpacketsize;
393 	struct cryptodesc *crdc;
394 	struct cryptop *crp;
395 	struct tdb_crypto *tc;
396 
397 	IPSEC_SPLASSERT_SOFTNET("ipcomp_output");
398 	sav = isr->sav;
399 	IPSEC_ASSERT(sav != NULL, ("ipcomp_output: null SA"));
400 	ipcompx = sav->tdb_compalgxform;
401 	IPSEC_ASSERT(ipcompx != NULL, ("ipcomp_output: null compression xform"));
402 
403 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
404 
405     /* Don't process the packet if it is too short */
406 	if (ralen < ipcompx->minlen) {
407 		IPCOMP_STATINC(IPCOMP_STAT_MINLEN);
408 		return ipsec_process_done(m,isr);
409 	}
410 
411 	hlen = IPCOMP_HLENGTH;
412 
413 	IPCOMP_STATINC(IPCOMP_STAT_OUTPUT);
414 
415 	/* Check for maximum packet size violations. */
416 	switch (sav->sah->saidx.dst.sa.sa_family) {
417 #ifdef INET
418 	case AF_INET:
419 		maxpacketsize =  IP_MAXPACKET;
420 		break;
421 #endif /* INET */
422 #ifdef INET6
423 	case AF_INET6:
424 		maxpacketsize =  IPV6_MAXPACKET;
425 		break;
426 #endif /* INET6 */
427 	default:
428 		IPCOMP_STATINC(IPCOMP_STAT_NOPF);
429 		DPRINTF(("ipcomp_output: unknown/unsupported protocol family %d"
430 		    ", IPCA %s/%08lx\n",
431 		    sav->sah->saidx.dst.sa.sa_family,
432 		    ipsec_address(&sav->sah->saidx.dst),
433 		    (u_long) ntohl(sav->spi)));
434 		error = EPFNOSUPPORT;
435 		goto bad;
436 	}
437 	if (skip + hlen + ralen > maxpacketsize) {
438 		IPCOMP_STATINC(IPCOMP_STAT_TOOBIG);
439 		DPRINTF(("ipcomp_output: packet in IPCA %s/%08lx got too big "
440 		    "(len %u, max len %u)\n",
441 		    ipsec_address(&sav->sah->saidx.dst),
442 		    (u_long) ntohl(sav->spi),
443 		    skip + hlen + ralen, maxpacketsize));
444 		error = EMSGSIZE;
445 		goto bad;
446 	}
447 
448 	/* Update the counters */
449 	IPCOMP_STATADD(IPCOMP_STAT_OBYTES, m->m_pkthdr.len - skip);
450 
451 	m = m_clone(m);
452 	if (m == NULL) {
453 		IPCOMP_STATINC(IPCOMP_STAT_HDROPS);
454 		DPRINTF(("ipcomp_output: cannot clone mbuf chain, IPCA %s/%08lx\n",
455 		    ipsec_address(&sav->sah->saidx.dst),
456 		    (u_long) ntohl(sav->spi)));
457 		error = ENOBUFS;
458 		goto bad;
459 	}
460 
461 	/* Ok now, we can pass to the crypto processing */
462 
463 	/* Get crypto descriptors */
464 	crp = crypto_getreq(1);
465 	if (crp == NULL) {
466 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
467 		DPRINTF(("ipcomp_output: failed to acquire crypto descriptor\n"));
468 		error = ENOBUFS;
469 		goto bad;
470 	}
471 	crdc = crp->crp_desc;
472 
473 	/* Compression descriptor */
474 	crdc->crd_skip = skip;
475 	crdc->crd_len = m->m_pkthdr.len - skip;
476 	crdc->crd_flags = CRD_F_COMP;
477 	crdc->crd_inject = skip;
478 
479 	/* Compression operation */
480 	crdc->crd_alg = ipcompx->type;
481 
482 	/* IPsec-specific opaque crypto info */
483 	tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
484 		M_XDATA, M_NOWAIT|M_ZERO);
485 	if (tc == NULL) {
486 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
487 		DPRINTF(("ipcomp_output: failed to allocate tdb_crypto\n"));
488 		crypto_freereq(crp);
489 		error = ENOBUFS;
490 		goto bad;
491 	}
492 
493 	tc->tc_isr = isr;
494 	tc->tc_spi = sav->spi;
495 	tc->tc_dst = sav->sah->saidx.dst;
496 	tc->tc_proto = sav->sah->saidx.proto;
497 	tc->tc_skip = skip;
498 	tc->tc_protoff = protoff;
499 
500 	/* Crypto operation descriptor */
501 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
502 	crp->crp_flags = CRYPTO_F_IMBUF;
503 	crp->crp_buf = m;
504 	crp->crp_callback = ipcomp_output_cb;
505 	crp->crp_opaque = tc;
506 	crp->crp_sid = sav->tdb_cryptoid;
507 
508 	return crypto_dispatch(crp);
509 bad:
510 	if (m)
511 		m_freem(m);
512 	return (error);
513 }
514 
515 /*
516  * IPComp output callback from the crypto driver.
517  */
518 static int
519 ipcomp_output_cb(struct cryptop *crp)
520 {
521 	struct tdb_crypto *tc;
522 	struct ipsecrequest *isr;
523 	struct secasvar *sav;
524 	struct mbuf *m, *mo;
525 	int s, error, skip, rlen, roff;
526 	u_int8_t prot;
527 	u_int16_t cpi;
528 	struct ipcomp * ipcomp;
529 
530 
531 	tc = (struct tdb_crypto *) crp->crp_opaque;
532 	IPSEC_ASSERT(tc != NULL, ("ipcomp_output_cb: null opaque data area!"));
533 	m = (struct mbuf *) crp->crp_buf;
534 	skip = tc->tc_skip;
535 	rlen = crp->crp_ilen - skip;
536 
537 	s = splsoftnet();
538 	mutex_enter(softnet_lock);
539 
540 	isr = tc->tc_isr;
541 	sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi, 0, 0);
542 	if (sav == NULL) {
543 		IPCOMP_STATINC(IPCOMP_STAT_NOTDB);
544 		DPRINTF(("ipcomp_output_cb: SA expired while in crypto\n"));
545 		error = ENOBUFS;		/*XXX*/
546 		goto bad;
547 	}
548 	IPSEC_ASSERT(isr->sav == sav, ("ipcomp_output_cb: SA changed\n"));
549 
550 	/* Check for crypto errors */
551 	if (crp->crp_etype) {
552 		/* Reset session ID */
553 		if (sav->tdb_cryptoid != 0)
554 			sav->tdb_cryptoid = crp->crp_sid;
555 
556 		if (crp->crp_etype == EAGAIN) {
557 			KEY_FREESAV(&sav);
558 			mutex_exit(softnet_lock);
559 			splx(s);
560 			return crypto_dispatch(crp);
561 		}
562 		IPCOMP_STATINC(IPCOMP_STAT_NOXFORM);
563 		DPRINTF(("ipcomp_output_cb: crypto error %d\n", crp->crp_etype));
564 		error = crp->crp_etype;
565 		goto bad;
566 	}
567 	/* Shouldn't happen... */
568 	if (m == NULL) {
569 		IPCOMP_STATINC(IPCOMP_STAT_CRYPTO);
570 		DPRINTF(("ipcomp_output_cb: bogus return buffer from crypto\n"));
571 		error = EINVAL;
572 		goto bad;
573 	}
574 	IPCOMP_STATINC(IPCOMP_STAT_HIST + sav->alg_comp);
575 
576 	if (rlen > crp->crp_olen) {
577 		/* Inject IPCOMP header */
578 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
579 		if (mo == NULL) {
580 			IPCOMP_STATINC(IPCOMP_STAT_WRAP);
581 			DPRINTF(("ipcomp_output: failed to inject IPCOMP header for "
582 					 "IPCA %s/%08lx\n",
583 						ipsec_address(&sav->sah->saidx.dst),
584 						(u_long) ntohl(sav->spi)));
585 			error = ENOBUFS;
586 			goto bad;
587 		}
588 		ipcomp = (struct ipcomp *)(mtod(mo, char *) + roff);
589 
590 		/* Initialize the IPCOMP header */
591 		/* XXX alignment always correct? */
592 		switch (sav->sah->saidx.dst.sa.sa_family) {
593 #ifdef INET
594 		case AF_INET:
595 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
596 			 break;
597 #endif /* INET */
598 #ifdef INET6
599 		case AF_INET6:
600 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
601 		break;
602 #endif
603 		}
604 		ipcomp->comp_flags = 0;
605 
606 		if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
607 			 cpi = sav->alg_enc;
608 		else
609 			cpi = ntohl(sav->spi) & 0xffff;
610 		ipcomp->comp_cpi = htons(cpi);
611 
612 		/* Fix Next Protocol in IPv4/IPv6 header */
613 		prot = IPPROTO_IPCOMP;
614 		m_copyback(m, tc->tc_protoff, sizeof(u_int8_t), (u_char *)&prot);
615 
616 		/* Adjust the length in the IP header */
617 		switch (sav->sah->saidx.dst.sa.sa_family) {
618 #ifdef INET
619 		case AF_INET:
620 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
621 			break;
622 #endif /* INET */
623 #ifdef INET6
624 		case AF_INET6:
625 			mtod(m, struct ip6_hdr *)->ip6_plen =
626 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
627 			break;
628 #endif /* INET6 */
629 		default:
630 			IPCOMP_STATINC(IPCOMP_STAT_NOPF);
631 			DPRINTF(("ipcomp_output: unknown/unsupported protocol "
632 			    "family %d, IPCA %s/%08lx\n",
633 			    sav->sah->saidx.dst.sa.sa_family,
634 			    ipsec_address(&sav->sah->saidx.dst),
635 			    (u_long) ntohl(sav->spi)));
636 			error = EPFNOSUPPORT;
637 			goto bad;
638 		}
639 	} else {
640 		/* compression was useless, we have lost time */
641 		IPCOMP_STATINC(IPCOMP_STAT_USELESS);
642 		DPRINTF(("ipcomp_output_cb: compression was useless : initial size was %d"
643 				   	"and compressed size is %d\n", rlen, crp->crp_olen));
644 	}
645 
646 
647 	/* Release the crypto descriptor */
648 	free(tc, M_XDATA);
649 	crypto_freereq(crp);
650 
651 	/* NB: m is reclaimed by ipsec_process_done. */
652 	error = ipsec_process_done(m, isr);
653 	KEY_FREESAV(&sav);
654 	mutex_exit(softnet_lock);
655 	splx(s);
656 	return error;
657 bad:
658 	if (sav)
659 		KEY_FREESAV(&sav);
660 	mutex_exit(softnet_lock);
661 	splx(s);
662 	if (m)
663 		m_freem(m);
664 	free(tc, M_XDATA);
665 	crypto_freereq(crp);
666 	return error;
667 }
668 
669 static struct xformsw ipcomp_xformsw = {
670 	XF_IPCOMP,		XFT_COMP,		"IPcomp",
671 	ipcomp_init,		ipcomp_zeroize,		ipcomp_input,
672 	ipcomp_output,
673 	NULL,
674 };
675 
676 INITFN void
677 ipcomp_attach(void)
678 {
679 	ipcompstat_percpu = percpu_alloc(sizeof(uint64_t) * IPCOMP_NSTATS);
680 	xform_register(&ipcomp_xformsw);
681 }
682 
683 #ifdef __FreeBSD__
684 SYSINIT(ipcomp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, ipcomp_attach, NULL)
685 #endif /* __FreeBSD__ */
686