xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
1 /*	$FreeBSD$	*/
2 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
3 
4 /*-
5  * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
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  *
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. The name of the author may not be used to endorse or promote products
17  *   derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 /* IP payload compression protocol (IPComp), see RFC 2393 */
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/mbuf.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/rwlock.h>
41 #include <sys/socket.h>
42 #include <sys/kernel.h>
43 #include <sys/protosw.h>
44 #include <sys/sysctl.h>
45 
46 #include <netinet/in.h>
47 #include <netinet/in_systm.h>
48 #include <netinet/ip.h>
49 #include <netinet/ip_var.h>
50 
51 #include <net/vnet.h>
52 
53 #include <netipsec/ipsec.h>
54 #include <netipsec/xform.h>
55 
56 #ifdef INET6
57 #include <netinet/ip6.h>
58 #include <netipsec/ipsec6.h>
59 #endif
60 
61 #include <netipsec/ipcomp.h>
62 #include <netipsec/ipcomp_var.h>
63 
64 #include <netipsec/key.h>
65 #include <netipsec/key_debug.h>
66 
67 #include <opencrypto/cryptodev.h>
68 #include <opencrypto/deflate.h>
69 #include <opencrypto/xform.h>
70 
71 VNET_DEFINE(int, ipcomp_enable) = 1;
72 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
73 VNET_PCPUSTAT_SYSINIT(ipcompstat);
74 
75 #ifdef VIMAGE
76 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
77 #endif /* VIMAGE */
78 
79 SYSCTL_DECL(_net_inet_ipcomp);
80 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
81 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
82 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
83     struct ipcompstat, ipcompstat,
84     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
85 
86 static int ipcomp_input_cb(struct cryptop *crp);
87 static int ipcomp_output_cb(struct cryptop *crp);
88 
89 struct comp_algo *
90 ipcomp_algorithm_lookup(int alg)
91 {
92 	if (alg >= IPCOMP_ALG_MAX)
93 		return NULL;
94 	switch (alg) {
95 	case SADB_X_CALG_DEFLATE:
96 		return &comp_algo_deflate;
97 	}
98 	return NULL;
99 }
100 
101 /*
102  * ipcomp_init() is called when an CPI is being set up.
103  */
104 static int
105 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
106 {
107 	struct comp_algo *tcomp;
108 	struct cryptoini cric;
109 
110 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
111 	tcomp = ipcomp_algorithm_lookup(sav->alg_enc);
112 	if (tcomp == NULL) {
113 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
114 			 sav->alg_comp));
115 		return EINVAL;
116 	}
117 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
118 	sav->tdb_xform = xsp;
119 	sav->tdb_compalgxform = tcomp;
120 
121 	/* Initialize crypto session */
122 	bzero(&cric, sizeof (cric));
123 	cric.cri_alg = sav->tdb_compalgxform->type;
124 
125 	return crypto_newsession(&sav->tdb_cryptoid, &cric, V_crypto_support);
126 }
127 
128 /*
129  * ipcomp_zeroize() used when IPCA is deleted
130  */
131 static int
132 ipcomp_zeroize(struct secasvar *sav)
133 {
134 	int err;
135 
136 	err = crypto_freesession(sav->tdb_cryptoid);
137 	sav->tdb_cryptoid = 0;
138 	return err;
139 }
140 
141 /*
142  * ipcomp_input() gets called to uncompress an input packet
143  */
144 static int
145 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
146 {
147 	struct tdb_crypto *tc;
148 	struct cryptodesc *crdc;
149 	struct cryptop *crp;
150 	struct ipcomp *ipcomp;
151 	caddr_t addr;
152 	int hlen = IPCOMP_HLENGTH;
153 
154 	/*
155 	 * Check that the next header of the IPComp is not IPComp again, before
156 	 * doing any real work.  Given it is not possible to do double
157 	 * compression it means someone is playing tricks on us.
158 	 */
159 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
160 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
161 		DPRINTF(("%s: m_pullup failed\n", __func__));
162 		return (ENOBUFS);
163 	}
164 	addr = (caddr_t) mtod(m, struct ip *) + skip;
165 	ipcomp = (struct ipcomp *)addr;
166 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
167 		m_freem(m);
168 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
169 		DPRINTF(("%s: recursive compression detected\n", __func__));
170 		return (EINVAL);
171 	}
172 
173 	/* Get crypto descriptors */
174 	crp = crypto_getreq(1);
175 	if (crp == NULL) {
176 		m_freem(m);
177 		DPRINTF(("%s: no crypto descriptors\n", __func__));
178 		IPCOMPSTAT_INC(ipcomps_crypto);
179 		return ENOBUFS;
180 	}
181 	/* Get IPsec-specific opaque pointer */
182 	tc = (struct tdb_crypto *) malloc(sizeof (*tc), M_XDATA, M_NOWAIT|M_ZERO);
183 	if (tc == NULL) {
184 		m_freem(m);
185 		crypto_freereq(crp);
186 		DPRINTF(("%s: cannot allocate tdb_crypto\n", __func__));
187 		IPCOMPSTAT_INC(ipcomps_crypto);
188 		return ENOBUFS;
189 	}
190 	crdc = crp->crp_desc;
191 
192 	crdc->crd_skip = skip + hlen;
193 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
194 	crdc->crd_inject = skip;
195 
196 	tc->tc_ptr = 0;
197 
198 	/* Decompression operation */
199 	crdc->crd_alg = sav->tdb_compalgxform->type;
200 
201 	/* Crypto operation descriptor */
202 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
203 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
204 	crp->crp_buf = (caddr_t) m;
205 	crp->crp_callback = ipcomp_input_cb;
206 	crp->crp_sid = sav->tdb_cryptoid;
207 	crp->crp_opaque = (caddr_t) tc;
208 
209 	/* These are passed as-is to the callback */
210 	tc->tc_spi = sav->spi;
211 	tc->tc_dst = sav->sah->saidx.dst;
212 	tc->tc_proto = sav->sah->saidx.proto;
213 	tc->tc_protoff = protoff;
214 	tc->tc_skip = skip;
215 	KEY_ADDREFSA(sav);
216 	tc->tc_sav = sav;
217 
218 	return crypto_dispatch(crp);
219 }
220 
221 /*
222  * IPComp input callback from the crypto driver.
223  */
224 static int
225 ipcomp_input_cb(struct cryptop *crp)
226 {
227 	char buf[INET6_ADDRSTRLEN];
228 	struct cryptodesc *crd;
229 	struct tdb_crypto *tc;
230 	int skip, protoff;
231 	struct mbuf *m;
232 	struct secasvar *sav;
233 	struct secasindex *saidx;
234 	int hlen = IPCOMP_HLENGTH, error, clen;
235 	u_int8_t nproto;
236 	caddr_t addr;
237 
238 	crd = crp->crp_desc;
239 
240 	tc = (struct tdb_crypto *) crp->crp_opaque;
241 	IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
242 	skip = tc->tc_skip;
243 	protoff = tc->tc_protoff;
244 	m = (struct mbuf *) crp->crp_buf;
245 
246 	sav = tc->tc_sav;
247 	IPSEC_ASSERT(sav != NULL, ("null SA!"));
248 
249 	saidx = &sav->sah->saidx;
250 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
251 		saidx->dst.sa.sa_family == AF_INET6,
252 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
253 
254 	/* Check for crypto errors */
255 	if (crp->crp_etype) {
256 		/* Reset the session ID */
257 		if (sav->tdb_cryptoid != 0)
258 			sav->tdb_cryptoid = crp->crp_sid;
259 
260 		if (crp->crp_etype == EAGAIN) {
261 			return crypto_dispatch(crp);
262 		}
263 		IPCOMPSTAT_INC(ipcomps_noxform);
264 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
265 		error = crp->crp_etype;
266 		goto bad;
267 	}
268 	/* Shouldn't happen... */
269 	if (m == NULL) {
270 		IPCOMPSTAT_INC(ipcomps_crypto);
271 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
272 		error = EINVAL;
273 		goto bad;
274 	}
275 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
276 
277 	clen = crp->crp_olen;		/* Length of data after processing */
278 
279 	/* Release the crypto descriptors */
280 	free(tc, M_XDATA), tc = NULL;
281 	crypto_freereq(crp), crp = NULL;
282 
283 	/* In case it's not done already, adjust the size of the mbuf chain */
284 	m->m_pkthdr.len = clen + hlen + skip;
285 
286 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == 0) {
287 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
288 		DPRINTF(("%s: m_pullup failed\n", __func__));
289 		error = EINVAL;				/*XXX*/
290 		goto bad;
291 	}
292 
293 	/* Keep the next protocol field */
294 	addr = (caddr_t) mtod(m, struct ip *) + skip;
295 	nproto = ((struct ipcomp *) addr)->comp_nxt;
296 
297 	/* Remove the IPCOMP header */
298 	error = m_striphdr(m, skip, hlen);
299 	if (error) {
300 		IPCOMPSTAT_INC(ipcomps_hdrops);
301 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
302 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
303 		    (u_long) ntohl(sav->spi)));
304 		goto bad;
305 	}
306 
307 	/* Restore the Next Protocol field */
308 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
309 
310 	switch (saidx->dst.sa.sa_family) {
311 #ifdef INET6
312 	case AF_INET6:
313 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
314 		break;
315 #endif
316 #ifdef INET
317 	case AF_INET:
318 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
319 		break;
320 #endif
321 	default:
322 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
323 		    saidx->dst.sa.sa_family, saidx);
324 	}
325 
326 	KEY_FREESAV(&sav);
327 	return error;
328 bad:
329 	if (sav)
330 		KEY_FREESAV(&sav);
331 	if (m)
332 		m_freem(m);
333 	if (tc != NULL)
334 		free(tc, M_XDATA);
335 	if (crp)
336 		crypto_freereq(crp);
337 	return error;
338 }
339 
340 /*
341  * IPComp output routine, called by ipsec[46]_process_packet()
342  */
343 static int
344 ipcomp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
345     int skip, int protoff)
346 {
347 	char buf[INET6_ADDRSTRLEN];
348 	struct secasvar *sav;
349 	struct comp_algo *ipcompx;
350 	int error, ralen, maxpacketsize;
351 	struct cryptodesc *crdc;
352 	struct cryptop *crp;
353 	struct tdb_crypto *tc;
354 
355 	sav = isr->sav;
356 	IPSEC_ASSERT(sav != NULL, ("null SA"));
357 	ipcompx = sav->tdb_compalgxform;
358 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
359 
360 	/*
361 	 * Do not touch the packet in case our payload to compress
362 	 * is lower than the minimal threshold of the compression
363 	 * alogrithm.  We will just send out the data uncompressed.
364 	 * See RFC 3173, 2.2. Non-Expansion Policy.
365 	 */
366 	if (m->m_pkthdr.len <= ipcompx->minlen) {
367 		IPCOMPSTAT_INC(ipcomps_threshold);
368 		return ipsec_process_done(m, isr);
369 	}
370 
371 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
372 	IPCOMPSTAT_INC(ipcomps_output);
373 
374 	/* Check for maximum packet size violations. */
375 	switch (sav->sah->saidx.dst.sa.sa_family) {
376 #ifdef INET
377 	case AF_INET:
378 		maxpacketsize = IP_MAXPACKET;
379 		break;
380 #endif /* INET */
381 #ifdef INET6
382 	case AF_INET6:
383 		maxpacketsize = IPV6_MAXPACKET;
384 		break;
385 #endif /* INET6 */
386 	default:
387 		IPCOMPSTAT_INC(ipcomps_nopf);
388 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
389 		    "IPCA %s/%08lx\n", __func__,
390 		    sav->sah->saidx.dst.sa.sa_family,
391 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
392 		    (u_long) ntohl(sav->spi)));
393 		error = EPFNOSUPPORT;
394 		goto bad;
395 	}
396 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
397 		IPCOMPSTAT_INC(ipcomps_toobig);
398 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
399 		    "(len %u, max len %u)\n", __func__,
400 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
401 		    (u_long) ntohl(sav->spi),
402 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
403 		error = EMSGSIZE;
404 		goto bad;
405 	}
406 
407 	/* Update the counters */
408 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
409 
410 	m = m_unshare(m, M_NOWAIT);
411 	if (m == NULL) {
412 		IPCOMPSTAT_INC(ipcomps_hdrops);
413 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
414 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
415 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
416 		error = ENOBUFS;
417 		goto bad;
418 	}
419 
420 	/* Ok now, we can pass to the crypto processing. */
421 
422 	/* Get crypto descriptors */
423 	crp = crypto_getreq(1);
424 	if (crp == NULL) {
425 		IPCOMPSTAT_INC(ipcomps_crypto);
426 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
427 		error = ENOBUFS;
428 		goto bad;
429 	}
430 	crdc = crp->crp_desc;
431 
432 	/* Compression descriptor */
433 	crdc->crd_skip = skip;
434 	crdc->crd_len = ralen;
435 	crdc->crd_flags = CRD_F_COMP;
436 	crdc->crd_inject = skip;
437 
438 	/* Compression operation */
439 	crdc->crd_alg = ipcompx->type;
440 
441 	/* IPsec-specific opaque crypto info */
442 	tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
443 		M_XDATA, M_NOWAIT|M_ZERO);
444 	if (tc == NULL) {
445 		IPCOMPSTAT_INC(ipcomps_crypto);
446 		DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
447 		crypto_freereq(crp);
448 		error = ENOBUFS;
449 		goto bad;
450 	}
451 
452 	tc->tc_isr = isr;
453 	KEY_ADDREFSA(sav);
454 	tc->tc_sav = sav;
455 	tc->tc_spi = sav->spi;
456 	tc->tc_dst = sav->sah->saidx.dst;
457 	tc->tc_proto = sav->sah->saidx.proto;
458 	tc->tc_protoff = protoff;
459 	tc->tc_skip = skip;
460 
461 	/* Crypto operation descriptor */
462 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
463 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
464 	crp->crp_buf = (caddr_t) m;
465 	crp->crp_callback = ipcomp_output_cb;
466 	crp->crp_opaque = (caddr_t) tc;
467 	crp->crp_sid = sav->tdb_cryptoid;
468 
469 	return crypto_dispatch(crp);
470 bad:
471 	if (m)
472 		m_freem(m);
473 	return (error);
474 }
475 
476 /*
477  * IPComp output callback from the crypto driver.
478  */
479 static int
480 ipcomp_output_cb(struct cryptop *crp)
481 {
482 	char buf[INET6_ADDRSTRLEN];
483 	struct tdb_crypto *tc;
484 	struct ipsecrequest *isr;
485 	struct secasvar *sav;
486 	struct mbuf *m;
487 	int error, skip;
488 
489 	tc = (struct tdb_crypto *) crp->crp_opaque;
490 	IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
491 	m = (struct mbuf *) crp->crp_buf;
492 	skip = tc->tc_skip;
493 
494 	isr = tc->tc_isr;
495 	IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
496 	IPSECREQUEST_LOCK(isr);
497 	sav = tc->tc_sav;
498 	/* With the isr lock released SA pointer can be updated. */
499 	if (sav != isr->sav) {
500 		IPCOMPSTAT_INC(ipcomps_notdb);
501 		DPRINTF(("%s: SA expired while in crypto\n", __func__));
502 		error = ENOBUFS;		/*XXX*/
503 		goto bad;
504 	}
505 
506 	/* Check for crypto errors */
507 	if (crp->crp_etype) {
508 		/* Reset the session ID */
509 		if (sav->tdb_cryptoid != 0)
510 			sav->tdb_cryptoid = crp->crp_sid;
511 
512 		if (crp->crp_etype == EAGAIN) {
513 			IPSECREQUEST_UNLOCK(isr);
514 			return crypto_dispatch(crp);
515 		}
516 		IPCOMPSTAT_INC(ipcomps_noxform);
517 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
518 		error = crp->crp_etype;
519 		goto bad;
520 	}
521 	/* Shouldn't happen... */
522 	if (m == NULL) {
523 		IPCOMPSTAT_INC(ipcomps_crypto);
524 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
525 		error = EINVAL;
526 		goto bad;
527 	}
528 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
529 
530 	if (crp->crp_ilen - skip > crp->crp_olen) {
531 		struct mbuf *mo;
532 		struct ipcomp *ipcomp;
533 		int roff;
534 		uint8_t prot;
535 
536 		/* Compression helped, inject IPCOMP header. */
537 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
538 		if (mo == NULL) {
539 			IPCOMPSTAT_INC(ipcomps_wrap);
540 			DPRINTF(("%s: IPCOMP header inject failed for IPCA %s/%08lx\n",
541 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
542 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
543 			error = ENOBUFS;
544 			goto bad;
545 		}
546 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
547 
548 		/* Initialize the IPCOMP header */
549 		/* XXX alignment always correct? */
550 		switch (sav->sah->saidx.dst.sa.sa_family) {
551 #ifdef INET
552 		case AF_INET:
553 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
554 			break;
555 #endif /* INET */
556 #ifdef INET6
557 		case AF_INET6:
558 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
559 			break;
560 #endif
561 		}
562 		ipcomp->comp_flags = 0;
563 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
564 
565 		/* Fix Next Protocol in IPv4/IPv6 header */
566 		prot = IPPROTO_IPCOMP;
567 		m_copyback(m, tc->tc_protoff, sizeof(u_int8_t),
568 		    (u_char *)&prot);
569 
570 		/* Adjust the length in the IP header */
571 		switch (sav->sah->saidx.dst.sa.sa_family) {
572 #ifdef INET
573 		case AF_INET:
574 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
575 			break;
576 #endif /* INET */
577 #ifdef INET6
578 		case AF_INET6:
579 			mtod(m, struct ip6_hdr *)->ip6_plen =
580 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
581 			break;
582 #endif /* INET6 */
583 		default:
584 			IPCOMPSTAT_INC(ipcomps_nopf);
585 			DPRINTF(("%s: unknown/unsupported protocol "
586 			    "family %d, IPCA %s/%08lx\n", __func__,
587 			    sav->sah->saidx.dst.sa.sa_family,
588 			    ipsec_address(&sav->sah->saidx.dst, buf,
589 				sizeof(buf)), (u_long) ntohl(sav->spi)));
590 			error = EPFNOSUPPORT;
591 			goto bad;
592 		}
593 	} else {
594 		/* Compression was useless, we have lost time. */
595 		IPCOMPSTAT_INC(ipcomps_uncompr);
596 		DPRINTF(("%s: compressions was useless %d - %d <= %d\n",
597 		    __func__, crp->crp_ilen, skip, crp->crp_olen));
598 		/* XXX remember state to not compress the next couple
599 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
600 	}
601 
602 	/* Release the crypto descriptor */
603 	free(tc, M_XDATA);
604 	crypto_freereq(crp);
605 
606 	/* NB: m is reclaimed by ipsec_process_done. */
607 	error = ipsec_process_done(m, isr);
608 	KEY_FREESAV(&sav);
609 	IPSECREQUEST_UNLOCK(isr);
610 	KEY_FREESP(&isr->sp);
611 	return (error);
612 bad:
613 	if (sav)
614 		KEY_FREESAV(&sav);
615 	IPSECREQUEST_UNLOCK(isr);
616 	KEY_FREESP(&isr->sp);
617 	if (m)
618 		m_freem(m);
619 	free(tc, M_XDATA);
620 	crypto_freereq(crp);
621 	return (error);
622 }
623 
624 static struct xformsw ipcomp_xformsw = {
625 	XF_IPCOMP,		XFT_COMP,		"IPcomp",
626 	ipcomp_init,		ipcomp_zeroize,		ipcomp_input,
627 	ipcomp_output
628 };
629 
630 static void
631 ipcomp_attach(void)
632 {
633 
634 	xform_register(&ipcomp_xformsw);
635 }
636 
637 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ipcomp_attach, NULL);
638