xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision 5e386598a6d77973b93c073080f0cc574edda9e2)
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/socket.h>
41 #include <sys/kernel.h>
42 #include <sys/protosw.h>
43 #include <sys/sysctl.h>
44 
45 #include <netinet/in.h>
46 #include <netinet/in_systm.h>
47 #include <netinet/ip.h>
48 #include <netinet/ip_var.h>
49 #include <netinet/ip_encap.h>
50 
51 #include <net/netisr.h>
52 #include <net/vnet.h>
53 
54 #include <netipsec/ipsec.h>
55 #include <netipsec/xform.h>
56 
57 #ifdef INET6
58 #include <netinet/ip6.h>
59 #include <netinet6/ip6_var.h>
60 #include <netipsec/ipsec6.h>
61 #endif
62 
63 #include <netipsec/ipcomp.h>
64 #include <netipsec/ipcomp_var.h>
65 
66 #include <netipsec/key.h>
67 #include <netipsec/key_debug.h>
68 
69 #include <opencrypto/cryptodev.h>
70 #include <opencrypto/deflate.h>
71 #include <opencrypto/xform.h>
72 
73 VNET_DEFINE(int, ipcomp_enable) = 1;
74 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
75 VNET_PCPUSTAT_SYSINIT(ipcompstat);
76 
77 #ifdef VIMAGE
78 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
79 #endif /* VIMAGE */
80 
81 SYSCTL_DECL(_net_inet_ipcomp);
82 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
83 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
84 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
85     struct ipcompstat, ipcompstat,
86     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
87 
88 static int ipcomp_input_cb(struct cryptop *crp);
89 static int ipcomp_output_cb(struct cryptop *crp);
90 
91 /*
92  * RFC 3173 p 2.2. Non-Expansion Policy:
93  * If the total size of a compressed payload and the IPComp header, as
94  * defined in section 3, is not smaller than the size of the original
95  * payload, the IP datagram MUST be sent in the original non-compressed
96  * form.
97  *
98  * When we use IPComp in tunnel mode, for small packets we will receive
99  * encapsulated IP-IP datagrams without any compression and without IPComp
100  * header.
101  */
102 static int
103 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
104 {
105 	struct secasvar *sav;
106 
107 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
108 	if (sav == NULL)
109 		return (0);
110 	key_freesav(&sav);
111 
112 	if (src->sa.sa_family == AF_INET)
113 		return (sizeof(struct in_addr) << 4);
114 	else
115 		return (sizeof(struct in6_addr) << 4);
116 }
117 
118 static int
119 ipcomp_nonexp_input(struct mbuf **mp, int *offp, int proto)
120 {
121 	int isr;
122 
123 	switch (proto) {
124 #ifdef INET
125 	case IPPROTO_IPV4:
126 		isr = NETISR_IP;
127 		break;
128 #endif
129 #ifdef INET6
130 	case IPPROTO_IPV6:
131 		isr = NETISR_IPV6;
132 		break;
133 #endif
134 	default:
135 		IPCOMPSTAT_INC(ipcomps_nopf);
136 		m_freem(*mp);
137 		return (IPPROTO_DONE);
138 	}
139 	m_adj(*mp, *offp);
140 	IPCOMPSTAT_ADD(ipcomps_ibytes, (*mp)->m_pkthdr.len);
141 	IPCOMPSTAT_INC(ipcomps_input);
142 	netisr_dispatch(isr, *mp);
143 	return (IPPROTO_DONE);
144 }
145 
146 /*
147  * ipcomp_init() is called when an CPI is being set up.
148  */
149 static int
150 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
151 {
152 	const struct comp_algo *tcomp;
153 	struct cryptoini cric;
154 
155 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
156 	tcomp = comp_algorithm_lookup(sav->alg_enc);
157 	if (tcomp == NULL) {
158 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
159 			 sav->alg_comp));
160 		return EINVAL;
161 	}
162 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
163 	sav->tdb_xform = xsp;
164 	sav->tdb_compalgxform = tcomp;
165 
166 	/* Initialize crypto session */
167 	bzero(&cric, sizeof (cric));
168 	cric.cri_alg = sav->tdb_compalgxform->type;
169 
170 	return crypto_newsession(&sav->tdb_cryptoid, &cric, V_crypto_support);
171 }
172 
173 /*
174  * ipcomp_zeroize() used when IPCA is deleted
175  */
176 static int
177 ipcomp_zeroize(struct secasvar *sav)
178 {
179 	int err;
180 
181 	err = crypto_freesession(sav->tdb_cryptoid);
182 	sav->tdb_cryptoid = 0;
183 	return err;
184 }
185 
186 /*
187  * ipcomp_input() gets called to uncompress an input packet
188  */
189 static int
190 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
191 {
192 	struct xform_data *xd;
193 	struct cryptodesc *crdc;
194 	struct cryptop *crp;
195 	struct ipcomp *ipcomp;
196 	caddr_t addr;
197 	int hlen = IPCOMP_HLENGTH;
198 
199 	/*
200 	 * Check that the next header of the IPComp is not IPComp again, before
201 	 * doing any real work.  Given it is not possible to do double
202 	 * compression it means someone is playing tricks on us.
203 	 */
204 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
205 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
206 		DPRINTF(("%s: m_pullup failed\n", __func__));
207 		return (ENOBUFS);
208 	}
209 	addr = (caddr_t) mtod(m, struct ip *) + skip;
210 	ipcomp = (struct ipcomp *)addr;
211 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
212 		m_freem(m);
213 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
214 		DPRINTF(("%s: recursive compression detected\n", __func__));
215 		return (EINVAL);
216 	}
217 
218 	/* Get crypto descriptors */
219 	crp = crypto_getreq(1);
220 	if (crp == NULL) {
221 		m_freem(m);
222 		DPRINTF(("%s: no crypto descriptors\n", __func__));
223 		IPCOMPSTAT_INC(ipcomps_crypto);
224 		return ENOBUFS;
225 	}
226 	/* Get IPsec-specific opaque pointer */
227 	xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
228 	if (xd == NULL) {
229 		DPRINTF(("%s: cannot allocate xform_data\n", __func__));
230 		IPCOMPSTAT_INC(ipcomps_crypto);
231 		crypto_freereq(crp);
232 		m_freem(m);
233 		return ENOBUFS;
234 	}
235 	crdc = crp->crp_desc;
236 
237 	crdc->crd_skip = skip + hlen;
238 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
239 	crdc->crd_inject = skip;
240 
241 	/* Decompression operation */
242 	crdc->crd_alg = sav->tdb_compalgxform->type;
243 
244 
245 	/* Crypto operation descriptor */
246 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
247 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
248 	crp->crp_buf = (caddr_t) m;
249 	crp->crp_callback = ipcomp_input_cb;
250 	crp->crp_opaque = (caddr_t) xd;
251 
252 	/* These are passed as-is to the callback */
253 	xd->sav = sav;
254 	xd->protoff = protoff;
255 	xd->skip = skip;
256 
257 	SECASVAR_LOCK(sav);
258 	crp->crp_sid = xd->cryptoid = sav->tdb_cryptoid;
259 	SECASVAR_UNLOCK(sav);
260 
261 	return crypto_dispatch(crp);
262 }
263 
264 /*
265  * IPComp input callback from the crypto driver.
266  */
267 static int
268 ipcomp_input_cb(struct cryptop *crp)
269 {
270 	char buf[IPSEC_ADDRSTRLEN];
271 	struct cryptodesc *crd;
272 	struct xform_data *xd;
273 	struct mbuf *m;
274 	struct secasvar *sav;
275 	struct secasindex *saidx;
276 	caddr_t addr;
277 	uint64_t cryptoid;
278 	int hlen = IPCOMP_HLENGTH, error, clen;
279 	int skip, protoff;
280 	uint8_t nproto;
281 
282 	crd = crp->crp_desc;
283 
284 	m = (struct mbuf *) crp->crp_buf;
285 	xd = (struct xform_data *) crp->crp_opaque;
286 	sav = xd->sav;
287 	skip = xd->skip;
288 	protoff = xd->protoff;
289 	cryptoid = xd->cryptoid;
290 	saidx = &sav->sah->saidx;
291 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
292 		saidx->dst.sa.sa_family == AF_INET6,
293 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
294 
295 	/* Check for crypto errors */
296 	if (crp->crp_etype) {
297 		if (crp->crp_etype == EAGAIN) {
298 			/* Reset the session ID */
299 			if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
300 				crypto_freesession(cryptoid);
301 			xd->cryptoid = crp->crp_sid;
302 			return (crypto_dispatch(crp));
303 		}
304 		IPCOMPSTAT_INC(ipcomps_noxform);
305 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
306 		error = crp->crp_etype;
307 		goto bad;
308 	}
309 	/* Shouldn't happen... */
310 	if (m == NULL) {
311 		IPCOMPSTAT_INC(ipcomps_crypto);
312 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
313 		error = EINVAL;
314 		goto bad;
315 	}
316 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
317 
318 	clen = crp->crp_olen;		/* Length of data after processing */
319 
320 	/* Release the crypto descriptors */
321 	free(xd, M_XDATA), xd = NULL;
322 	crypto_freereq(crp), crp = NULL;
323 
324 	/* In case it's not done already, adjust the size of the mbuf chain */
325 	m->m_pkthdr.len = clen + hlen + skip;
326 
327 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
328 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
329 		DPRINTF(("%s: m_pullup failed\n", __func__));
330 		error = EINVAL;				/*XXX*/
331 		goto bad;
332 	}
333 
334 	/* Keep the next protocol field */
335 	addr = (caddr_t) mtod(m, struct ip *) + skip;
336 	nproto = ((struct ipcomp *) addr)->comp_nxt;
337 
338 	/* Remove the IPCOMP header */
339 	error = m_striphdr(m, skip, hlen);
340 	if (error) {
341 		IPCOMPSTAT_INC(ipcomps_hdrops);
342 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
343 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
344 		    (u_long) ntohl(sav->spi)));
345 		goto bad;
346 	}
347 
348 	/* Restore the Next Protocol field */
349 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
350 
351 	switch (saidx->dst.sa.sa_family) {
352 #ifdef INET6
353 	case AF_INET6:
354 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
355 		break;
356 #endif
357 #ifdef INET
358 	case AF_INET:
359 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
360 		break;
361 #endif
362 	default:
363 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
364 		    saidx->dst.sa.sa_family, saidx);
365 	}
366 	return error;
367 bad:
368 	if (sav != NULL)
369 		key_freesav(&sav);
370 	if (m != NULL)
371 		m_freem(m);
372 	if (xd != NULL)
373 		free(xd, M_XDATA);
374 	if (crp != NULL)
375 		crypto_freereq(crp);
376 	return error;
377 }
378 
379 /*
380  * IPComp output routine, called by ipsec[46]_perform_request()
381  */
382 static int
383 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
384     u_int idx, int skip, int protoff)
385 {
386 	char buf[IPSEC_ADDRSTRLEN];
387 	const struct comp_algo *ipcompx;
388 	struct cryptodesc *crdc;
389 	struct cryptop *crp;
390 	struct xform_data *xd;
391 	int error, ralen, maxpacketsize;
392 
393 	IPSEC_ASSERT(sav != NULL, ("null SA"));
394 	ipcompx = sav->tdb_compalgxform;
395 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
396 
397 	/*
398 	 * Do not touch the packet in case our payload to compress
399 	 * is lower than the minimal threshold of the compression
400 	 * alogrithm.  We will just send out the data uncompressed.
401 	 * See RFC 3173, 2.2. Non-Expansion Policy.
402 	 */
403 	if (m->m_pkthdr.len <= ipcompx->minlen) {
404 		IPCOMPSTAT_INC(ipcomps_threshold);
405 		return ipsec_process_done(m, sp, sav, idx);
406 	}
407 
408 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
409 	IPCOMPSTAT_INC(ipcomps_output);
410 
411 	/* Check for maximum packet size violations. */
412 	switch (sav->sah->saidx.dst.sa.sa_family) {
413 #ifdef INET
414 	case AF_INET:
415 		maxpacketsize = IP_MAXPACKET;
416 		break;
417 #endif /* INET */
418 #ifdef INET6
419 	case AF_INET6:
420 		maxpacketsize = IPV6_MAXPACKET;
421 		break;
422 #endif /* INET6 */
423 	default:
424 		IPCOMPSTAT_INC(ipcomps_nopf);
425 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
426 		    "IPCA %s/%08lx\n", __func__,
427 		    sav->sah->saidx.dst.sa.sa_family,
428 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
429 		    (u_long) ntohl(sav->spi)));
430 		error = EPFNOSUPPORT;
431 		goto bad;
432 	}
433 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
434 		IPCOMPSTAT_INC(ipcomps_toobig);
435 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
436 		    "(len %u, max len %u)\n", __func__,
437 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
438 		    (u_long) ntohl(sav->spi),
439 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
440 		error = EMSGSIZE;
441 		goto bad;
442 	}
443 
444 	/* Update the counters */
445 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
446 
447 	m = m_unshare(m, M_NOWAIT);
448 	if (m == NULL) {
449 		IPCOMPSTAT_INC(ipcomps_hdrops);
450 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
451 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
452 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
453 		error = ENOBUFS;
454 		goto bad;
455 	}
456 
457 	/* Ok now, we can pass to the crypto processing. */
458 
459 	/* Get crypto descriptors */
460 	crp = crypto_getreq(1);
461 	if (crp == NULL) {
462 		IPCOMPSTAT_INC(ipcomps_crypto);
463 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
464 		error = ENOBUFS;
465 		goto bad;
466 	}
467 	crdc = crp->crp_desc;
468 
469 	/* Compression descriptor */
470 	crdc->crd_skip = skip;
471 	crdc->crd_len = ralen;
472 	crdc->crd_flags = CRD_F_COMP;
473 	crdc->crd_inject = skip;
474 
475 	/* Compression operation */
476 	crdc->crd_alg = ipcompx->type;
477 
478 	/* IPsec-specific opaque crypto info */
479 	xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
480 	if (xd == NULL) {
481 		IPCOMPSTAT_INC(ipcomps_crypto);
482 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
483 		crypto_freereq(crp);
484 		error = ENOBUFS;
485 		goto bad;
486 	}
487 
488 	xd->sp = sp;
489 	xd->sav = sav;
490 	xd->idx = idx;
491 	xd->skip = skip;
492 	xd->protoff = protoff;
493 
494 	/* Crypto operation descriptor */
495 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
496 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
497 	crp->crp_buf = (caddr_t) m;
498 	crp->crp_callback = ipcomp_output_cb;
499 	crp->crp_opaque = (caddr_t) xd;
500 
501 	SECASVAR_LOCK(sav);
502 	crp->crp_sid = xd->cryptoid = sav->tdb_cryptoid;
503 	SECASVAR_UNLOCK(sav);
504 
505 	return crypto_dispatch(crp);
506 bad:
507 	if (m)
508 		m_freem(m);
509 	return (error);
510 }
511 
512 /*
513  * IPComp output callback from the crypto driver.
514  */
515 static int
516 ipcomp_output_cb(struct cryptop *crp)
517 {
518 	char buf[IPSEC_ADDRSTRLEN];
519 	struct xform_data *xd;
520 	struct secpolicy *sp;
521 	struct secasvar *sav;
522 	struct mbuf *m;
523 	uint64_t cryptoid;
524 	u_int idx;
525 	int error, skip, protoff;
526 
527 	m = (struct mbuf *) crp->crp_buf;
528 	xd = (struct xform_data *) crp->crp_opaque;
529 	idx = xd->idx;
530 	sp = xd->sp;
531 	sav = xd->sav;
532 	skip = xd->skip;
533 	protoff = xd->protoff;
534 	cryptoid = xd->cryptoid;
535 
536 	/* Check for crypto errors */
537 	if (crp->crp_etype) {
538 		if (crp->crp_etype == EAGAIN) {
539 			/* Reset the session ID */
540 			if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
541 				crypto_freesession(cryptoid);
542 			xd->cryptoid = crp->crp_sid;
543 			return (crypto_dispatch(crp));
544 		}
545 		IPCOMPSTAT_INC(ipcomps_noxform);
546 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
547 		error = crp->crp_etype;
548 		goto bad;
549 	}
550 	/* Shouldn't happen... */
551 	if (m == NULL) {
552 		IPCOMPSTAT_INC(ipcomps_crypto);
553 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
554 		error = EINVAL;
555 		goto bad;
556 	}
557 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
558 
559 	if (crp->crp_ilen - skip > crp->crp_olen) {
560 		struct mbuf *mo;
561 		struct ipcomp *ipcomp;
562 		int roff;
563 		uint8_t prot;
564 
565 		/* Compression helped, inject IPCOMP header. */
566 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
567 		if (mo == NULL) {
568 			IPCOMPSTAT_INC(ipcomps_wrap);
569 			DPRINTF(("%s: IPCOMP header inject failed "
570 			    "for IPCA %s/%08lx\n",
571 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
572 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
573 			error = ENOBUFS;
574 			goto bad;
575 		}
576 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
577 
578 		/* Initialize the IPCOMP header */
579 		/* XXX alignment always correct? */
580 		switch (sav->sah->saidx.dst.sa.sa_family) {
581 #ifdef INET
582 		case AF_INET:
583 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
584 			break;
585 #endif /* INET */
586 #ifdef INET6
587 		case AF_INET6:
588 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
589 			break;
590 #endif
591 		}
592 		ipcomp->comp_flags = 0;
593 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
594 
595 		/* Fix Next Protocol in IPv4/IPv6 header */
596 		prot = IPPROTO_IPCOMP;
597 		m_copyback(m, protoff, sizeof(u_int8_t),
598 		    (u_char *)&prot);
599 
600 		/* Adjust the length in the IP header */
601 		switch (sav->sah->saidx.dst.sa.sa_family) {
602 #ifdef INET
603 		case AF_INET:
604 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
605 			break;
606 #endif /* INET */
607 #ifdef INET6
608 		case AF_INET6:
609 			mtod(m, struct ip6_hdr *)->ip6_plen =
610 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
611 			break;
612 #endif /* INET6 */
613 		default:
614 			IPCOMPSTAT_INC(ipcomps_nopf);
615 			DPRINTF(("%s: unknown/unsupported protocol "
616 			    "family %d, IPCA %s/%08lx\n", __func__,
617 			    sav->sah->saidx.dst.sa.sa_family,
618 			    ipsec_address(&sav->sah->saidx.dst, buf,
619 				sizeof(buf)), (u_long) ntohl(sav->spi)));
620 			error = EPFNOSUPPORT;
621 			goto bad;
622 		}
623 	} else {
624 		/* Compression was useless, we have lost time. */
625 		IPCOMPSTAT_INC(ipcomps_uncompr);
626 		DPRINTF(("%s: compressions was useless %d - %d <= %d\n",
627 		    __func__, crp->crp_ilen, skip, crp->crp_olen));
628 		/* XXX remember state to not compress the next couple
629 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
630 	}
631 
632 	/* Release the crypto descriptor */
633 	free(xd, M_XDATA);
634 	crypto_freereq(crp);
635 
636 	/* NB: m is reclaimed by ipsec_process_done. */
637 	error = ipsec_process_done(m, sp, sav, idx);
638 	return (error);
639 bad:
640 	if (m)
641 		m_freem(m);
642 	free(xd, M_XDATA);
643 	crypto_freereq(crp);
644 	key_freesav(&sav);
645 	key_freesp(&sp);
646 	return (error);
647 }
648 
649 #ifdef INET
650 static const struct encaptab *ipe4_cookie = NULL;
651 extern struct domain inetdomain;
652 static struct protosw ipcomp4_protosw = {
653 	.pr_type =	SOCK_RAW,
654 	.pr_domain =	&inetdomain,
655 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
656 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
657 	.pr_input =	ipcomp_nonexp_input,
658 	.pr_output =	rip_output,
659 	.pr_ctloutput =	rip_ctloutput,
660 	.pr_usrreqs =	&rip_usrreqs
661 };
662 
663 static int
664 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
665     void *arg __unused)
666 {
667 	union sockaddr_union src, dst;
668 	const struct ip *ip;
669 
670 	if (V_ipcomp_enable == 0)
671 		return (0);
672 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
673 		return (0);
674 	bzero(&src, sizeof(src));
675 	bzero(&dst, sizeof(dst));
676 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
677 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
678 	ip = mtod(m, const struct ip *);
679 	src.sin.sin_addr = ip->ip_src;
680 	dst.sin.sin_addr = ip->ip_dst;
681 	return (ipcomp_encapcheck(&src, &dst));
682 }
683 #endif
684 #ifdef INET6
685 static const struct encaptab *ipe6_cookie = NULL;
686 extern struct domain inet6domain;
687 static struct protosw ipcomp6_protosw = {
688 	.pr_type =	SOCK_RAW,
689 	.pr_domain =	&inet6domain,
690 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
691 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
692 	.pr_input =	ipcomp_nonexp_input,
693 	.pr_output =	rip6_output,
694 	.pr_ctloutput =	rip6_ctloutput,
695 	.pr_usrreqs =	&rip6_usrreqs
696 };
697 
698 static int
699 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
700     void *arg __unused)
701 {
702 	union sockaddr_union src, dst;
703 	const struct ip6_hdr *ip6;
704 
705 	if (V_ipcomp_enable == 0)
706 		return (0);
707 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
708 		return (0);
709 	bzero(&src, sizeof(src));
710 	bzero(&dst, sizeof(dst));
711 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
712 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
713 	ip6 = mtod(m, const struct ip6_hdr *);
714 	src.sin6.sin6_addr = ip6->ip6_src;
715 	dst.sin6.sin6_addr = ip6->ip6_dst;
716 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
717 		/* XXX: sa6_recoverscope() */
718 		src.sin6.sin6_scope_id =
719 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
720 		src.sin6.sin6_addr.s6_addr16[1] = 0;
721 	}
722 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
723 		/* XXX: sa6_recoverscope() */
724 		dst.sin6.sin6_scope_id =
725 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
726 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
727 	}
728 	return (ipcomp_encapcheck(&src, &dst));
729 }
730 #endif
731 
732 static struct xformsw ipcomp_xformsw = {
733 	.xf_type =	XF_IPCOMP,
734 	.xf_name =	"IPcomp",
735 	.xf_init =	ipcomp_init,
736 	.xf_zeroize =	ipcomp_zeroize,
737 	.xf_input =	ipcomp_input,
738 	.xf_output =	ipcomp_output,
739 };
740 
741 static void
742 ipcomp_attach(void)
743 {
744 
745 #ifdef INET
746 	ipe4_cookie = encap_attach_func(AF_INET, -1,
747 	    ipcomp4_nonexp_encapcheck, &ipcomp4_protosw, NULL);
748 #endif
749 #ifdef INET6
750 	ipe6_cookie = encap_attach_func(AF_INET6, -1,
751 	    ipcomp6_nonexp_encapcheck, &ipcomp6_protosw, NULL);
752 #endif
753 	xform_attach(&ipcomp_xformsw);
754 }
755 
756 static void
757 ipcomp_detach(void)
758 {
759 
760 #ifdef INET
761 	encap_detach(ipe4_cookie);
762 #endif
763 #ifdef INET6
764 	encap_detach(ipe6_cookie);
765 #endif
766 	xform_detach(&ipcomp_xformsw);
767 }
768 
769 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
770     ipcomp_attach, NULL);
771 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
772     ipcomp_detach, NULL);
773