xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision 1a498d2e689f9e8220e2ad64b018eb1f0d11127e)
1 /*	$FreeBSD$	*/
2 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
3 
4 /*-
5  * SPDX-License-Identifier: BSD-3-Clause
6  *
7  * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *   notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *   notice, this list of conditions and the following disclaimer in the
17  *   documentation and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote products
19  *   derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /* IP payload compression protocol (IPComp), see RFC 2393 */
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/mbuf.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/socket.h>
43 #include <sys/kernel.h>
44 #include <sys/protosw.h>
45 #include <sys/sysctl.h>
46 
47 #include <netinet/in.h>
48 #include <netinet/in_systm.h>
49 #include <netinet/ip.h>
50 #include <netinet/ip_var.h>
51 #include <netinet/ip_encap.h>
52 
53 #include <net/netisr.h>
54 #include <net/vnet.h>
55 
56 #include <netipsec/ipsec.h>
57 #include <netipsec/xform.h>
58 
59 #ifdef INET6
60 #include <netinet/ip6.h>
61 #include <netinet6/ip6_var.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 <opencrypto/cryptodev.h>
72 #include <opencrypto/deflate.h>
73 #include <opencrypto/xform.h>
74 
75 VNET_DEFINE(int, ipcomp_enable) = 1;
76 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
77 VNET_PCPUSTAT_SYSINIT(ipcompstat);
78 
79 #ifdef VIMAGE
80 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
81 #endif /* VIMAGE */
82 
83 SYSCTL_DECL(_net_inet_ipcomp);
84 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
85 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
86 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
87     struct ipcompstat, ipcompstat,
88     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
89 
90 static int ipcomp_input_cb(struct cryptop *crp);
91 static int ipcomp_output_cb(struct cryptop *crp);
92 
93 /*
94  * RFC 3173 p 2.2. Non-Expansion Policy:
95  * If the total size of a compressed payload and the IPComp header, as
96  * defined in section 3, is not smaller than the size of the original
97  * payload, the IP datagram MUST be sent in the original non-compressed
98  * form.
99  *
100  * When we use IPComp in tunnel mode, for small packets we will receive
101  * encapsulated IP-IP datagrams without any compression and without IPComp
102  * header.
103  */
104 static int
105 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
106 {
107 	struct secasvar *sav;
108 
109 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
110 	if (sav == NULL)
111 		return (0);
112 	key_freesav(&sav);
113 
114 	if (src->sa.sa_family == AF_INET)
115 		return (sizeof(struct in_addr) << 4);
116 	else
117 		return (sizeof(struct in6_addr) << 4);
118 }
119 
120 static int
121 ipcomp_nonexp_input(struct mbuf *m, int off, int proto, void *arg __unused)
122 {
123 	int isr;
124 
125 	switch (proto) {
126 #ifdef INET
127 	case IPPROTO_IPV4:
128 		isr = NETISR_IP;
129 		break;
130 #endif
131 #ifdef INET6
132 	case IPPROTO_IPV6:
133 		isr = NETISR_IPV6;
134 		break;
135 #endif
136 	default:
137 		IPCOMPSTAT_INC(ipcomps_nopf);
138 		m_freem(m);
139 		return (IPPROTO_DONE);
140 	}
141 	m_adj(m, off);
142 	IPCOMPSTAT_ADD(ipcomps_ibytes, m->m_pkthdr.len);
143 	IPCOMPSTAT_INC(ipcomps_input);
144 	netisr_dispatch(isr, m);
145 	return (IPPROTO_DONE);
146 }
147 
148 /*
149  * ipcomp_init() is called when an CPI is being set up.
150  */
151 static int
152 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
153 {
154 	const struct comp_algo *tcomp;
155 	struct cryptoini cric;
156 
157 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
158 	tcomp = comp_algorithm_lookup(sav->alg_enc);
159 	if (tcomp == NULL) {
160 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
161 			 sav->alg_comp));
162 		return EINVAL;
163 	}
164 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
165 	sav->tdb_xform = xsp;
166 	sav->tdb_compalgxform = tcomp;
167 
168 	/* Initialize crypto session */
169 	bzero(&cric, sizeof (cric));
170 	cric.cri_alg = sav->tdb_compalgxform->type;
171 
172 	return crypto_newsession(&sav->tdb_cryptoid, &cric, V_crypto_support);
173 }
174 
175 /*
176  * ipcomp_zeroize() used when IPCA is deleted
177  */
178 static int
179 ipcomp_zeroize(struct secasvar *sav)
180 {
181 
182 	crypto_freesession(sav->tdb_cryptoid);
183 	sav->tdb_cryptoid = NULL;
184 	return 0;
185 }
186 
187 /*
188  * ipcomp_input() gets called to uncompress an input packet
189  */
190 static int
191 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
192 {
193 	struct xform_data *xd;
194 	struct cryptodesc *crdc;
195 	struct cryptop *crp;
196 	struct ipcomp *ipcomp;
197 	caddr_t addr;
198 	int error, hlen = IPCOMP_HLENGTH;
199 
200 	/*
201 	 * Check that the next header of the IPComp is not IPComp again, before
202 	 * doing any real work.  Given it is not possible to do double
203 	 * compression it means someone is playing tricks on us.
204 	 */
205 	error = ENOBUFS;
206 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
207 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
208 		DPRINTF(("%s: m_pullup failed\n", __func__));
209 		key_freesav(&sav);
210 		return (error);
211 	}
212 	addr = (caddr_t) mtod(m, struct ip *) + skip;
213 	ipcomp = (struct ipcomp *)addr;
214 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
215 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
216 		DPRINTF(("%s: recursive compression detected\n", __func__));
217 		error = EINVAL;
218 		goto bad;
219 	}
220 
221 	/* Get crypto descriptors */
222 	crp = crypto_getreq(1);
223 	if (crp == NULL) {
224 		DPRINTF(("%s: no crypto descriptors\n", __func__));
225 		IPCOMPSTAT_INC(ipcomps_crypto);
226 		goto bad;
227 	}
228 	/* Get IPsec-specific opaque pointer */
229 	xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
230 	if (xd == NULL) {
231 		DPRINTF(("%s: cannot allocate xform_data\n", __func__));
232 		IPCOMPSTAT_INC(ipcomps_crypto);
233 		crypto_freereq(crp);
234 		goto bad;
235 	}
236 	crdc = crp->crp_desc;
237 
238 	crdc->crd_skip = skip + hlen;
239 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
240 	crdc->crd_inject = skip;
241 
242 	/* Decompression operation */
243 	crdc->crd_alg = sav->tdb_compalgxform->type;
244 
245 
246 	/* Crypto operation descriptor */
247 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
248 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
249 	crp->crp_buf = (caddr_t) m;
250 	crp->crp_callback = ipcomp_input_cb;
251 	crp->crp_opaque = (caddr_t) xd;
252 
253 	/* These are passed as-is to the callback */
254 	xd->sav = sav;
255 	xd->protoff = protoff;
256 	xd->skip = skip;
257 	xd->vnet = curvnet;
258 
259 	SECASVAR_LOCK(sav);
260 	crp->crp_session = xd->cryptoid = sav->tdb_cryptoid;
261 	SECASVAR_UNLOCK(sav);
262 
263 	return crypto_dispatch(crp);
264 bad:
265 	m_freem(m);
266 	key_freesav(&sav);
267 	return (error);
268 }
269 
270 /*
271  * IPComp input callback from the crypto driver.
272  */
273 static int
274 ipcomp_input_cb(struct cryptop *crp)
275 {
276 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
277 	struct xform_data *xd;
278 	struct mbuf *m;
279 	struct secasvar *sav;
280 	struct secasindex *saidx;
281 	caddr_t addr;
282 	crypto_session_t cryptoid;
283 	int hlen = IPCOMP_HLENGTH, error, clen;
284 	int skip, protoff;
285 	uint8_t nproto;
286 
287 	m = (struct mbuf *) crp->crp_buf;
288 	xd = (struct xform_data *) crp->crp_opaque;
289 	CURVNET_SET(xd->vnet);
290 	sav = xd->sav;
291 	skip = xd->skip;
292 	protoff = xd->protoff;
293 	cryptoid = xd->cryptoid;
294 	saidx = &sav->sah->saidx;
295 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
296 		saidx->dst.sa.sa_family == AF_INET6,
297 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
298 
299 	/* Check for crypto errors */
300 	if (crp->crp_etype) {
301 		if (crp->crp_etype == EAGAIN) {
302 			/* Reset the session ID */
303 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
304 				crypto_freesession(cryptoid);
305 			xd->cryptoid = crp->crp_session;
306 			CURVNET_RESTORE();
307 			return (crypto_dispatch(crp));
308 		}
309 		IPCOMPSTAT_INC(ipcomps_noxform);
310 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
311 		error = crp->crp_etype;
312 		goto bad;
313 	}
314 	/* Shouldn't happen... */
315 	if (m == NULL) {
316 		IPCOMPSTAT_INC(ipcomps_crypto);
317 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
318 		error = EINVAL;
319 		goto bad;
320 	}
321 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
322 
323 	clen = crp->crp_olen;		/* Length of data after processing */
324 
325 	/* Release the crypto descriptors */
326 	free(xd, M_XDATA), xd = NULL;
327 	crypto_freereq(crp), crp = NULL;
328 
329 	/* In case it's not done already, adjust the size of the mbuf chain */
330 	m->m_pkthdr.len = clen + hlen + skip;
331 
332 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
333 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
334 		DPRINTF(("%s: m_pullup failed\n", __func__));
335 		error = EINVAL;				/*XXX*/
336 		goto bad;
337 	}
338 
339 	/* Keep the next protocol field */
340 	addr = (caddr_t) mtod(m, struct ip *) + skip;
341 	nproto = ((struct ipcomp *) addr)->comp_nxt;
342 
343 	/* Remove the IPCOMP header */
344 	error = m_striphdr(m, skip, hlen);
345 	if (error) {
346 		IPCOMPSTAT_INC(ipcomps_hdrops);
347 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
348 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
349 		    (u_long) ntohl(sav->spi)));
350 		goto bad;
351 	}
352 
353 	/* Restore the Next Protocol field */
354 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
355 
356 	switch (saidx->dst.sa.sa_family) {
357 #ifdef INET6
358 	case AF_INET6:
359 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
360 		break;
361 #endif
362 #ifdef INET
363 	case AF_INET:
364 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
365 		break;
366 #endif
367 	default:
368 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
369 		    saidx->dst.sa.sa_family, saidx);
370 	}
371 	CURVNET_RESTORE();
372 	return error;
373 bad:
374 	CURVNET_RESTORE();
375 	if (sav != NULL)
376 		key_freesav(&sav);
377 	if (m != NULL)
378 		m_freem(m);
379 	if (xd != NULL)
380 		free(xd, M_XDATA);
381 	if (crp != NULL)
382 		crypto_freereq(crp);
383 	return error;
384 }
385 
386 /*
387  * IPComp output routine, called by ipsec[46]_perform_request()
388  */
389 static int
390 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
391     u_int idx, int skip, int protoff)
392 {
393 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
394 	const struct comp_algo *ipcompx;
395 	struct cryptodesc *crdc;
396 	struct cryptop *crp;
397 	struct xform_data *xd;
398 	int error, ralen, maxpacketsize;
399 
400 	IPSEC_ASSERT(sav != NULL, ("null SA"));
401 	ipcompx = sav->tdb_compalgxform;
402 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
403 
404 	/*
405 	 * Do not touch the packet in case our payload to compress
406 	 * is lower than the minimal threshold of the compression
407 	 * alogrithm.  We will just send out the data uncompressed.
408 	 * See RFC 3173, 2.2. Non-Expansion Policy.
409 	 */
410 	if (m->m_pkthdr.len <= ipcompx->minlen) {
411 		IPCOMPSTAT_INC(ipcomps_threshold);
412 		return ipsec_process_done(m, sp, sav, idx);
413 	}
414 
415 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
416 	IPCOMPSTAT_INC(ipcomps_output);
417 
418 	/* Check for maximum packet size violations. */
419 	switch (sav->sah->saidx.dst.sa.sa_family) {
420 #ifdef INET
421 	case AF_INET:
422 		maxpacketsize = IP_MAXPACKET;
423 		break;
424 #endif /* INET */
425 #ifdef INET6
426 	case AF_INET6:
427 		maxpacketsize = IPV6_MAXPACKET;
428 		break;
429 #endif /* INET6 */
430 	default:
431 		IPCOMPSTAT_INC(ipcomps_nopf);
432 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
433 		    "IPCA %s/%08lx\n", __func__,
434 		    sav->sah->saidx.dst.sa.sa_family,
435 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
436 		    (u_long) ntohl(sav->spi)));
437 		error = EPFNOSUPPORT;
438 		goto bad;
439 	}
440 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
441 		IPCOMPSTAT_INC(ipcomps_toobig);
442 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
443 		    "(len %u, max len %u)\n", __func__,
444 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
445 		    (u_long) ntohl(sav->spi),
446 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
447 		error = EMSGSIZE;
448 		goto bad;
449 	}
450 
451 	/* Update the counters */
452 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
453 
454 	m = m_unshare(m, M_NOWAIT);
455 	if (m == NULL) {
456 		IPCOMPSTAT_INC(ipcomps_hdrops);
457 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
458 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
459 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
460 		error = ENOBUFS;
461 		goto bad;
462 	}
463 
464 	/* Ok now, we can pass to the crypto processing. */
465 
466 	/* Get crypto descriptors */
467 	crp = crypto_getreq(1);
468 	if (crp == NULL) {
469 		IPCOMPSTAT_INC(ipcomps_crypto);
470 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
471 		error = ENOBUFS;
472 		goto bad;
473 	}
474 	crdc = crp->crp_desc;
475 
476 	/* Compression descriptor */
477 	crdc->crd_skip = skip;
478 	crdc->crd_len = ralen;
479 	crdc->crd_flags = CRD_F_COMP;
480 	crdc->crd_inject = skip;
481 
482 	/* Compression operation */
483 	crdc->crd_alg = ipcompx->type;
484 
485 	/* IPsec-specific opaque crypto info */
486 	xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
487 	if (xd == NULL) {
488 		IPCOMPSTAT_INC(ipcomps_crypto);
489 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
490 		crypto_freereq(crp);
491 		error = ENOBUFS;
492 		goto bad;
493 	}
494 
495 	xd->sp = sp;
496 	xd->sav = sav;
497 	xd->idx = idx;
498 	xd->skip = skip;
499 	xd->protoff = protoff;
500 	xd->vnet = curvnet;
501 
502 	/* Crypto operation descriptor */
503 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
504 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
505 	crp->crp_buf = (caddr_t) m;
506 	crp->crp_callback = ipcomp_output_cb;
507 	crp->crp_opaque = (caddr_t) xd;
508 
509 	SECASVAR_LOCK(sav);
510 	crp->crp_session = xd->cryptoid = sav->tdb_cryptoid;
511 	SECASVAR_UNLOCK(sav);
512 
513 	return crypto_dispatch(crp);
514 bad:
515 	if (m)
516 		m_freem(m);
517 	key_freesav(&sav);
518 	key_freesp(&sp);
519 	return (error);
520 }
521 
522 /*
523  * IPComp output callback from the crypto driver.
524  */
525 static int
526 ipcomp_output_cb(struct cryptop *crp)
527 {
528 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
529 	struct xform_data *xd;
530 	struct secpolicy *sp;
531 	struct secasvar *sav;
532 	struct mbuf *m;
533 	crypto_session_t cryptoid;
534 	u_int idx;
535 	int error, skip, protoff;
536 
537 	m = (struct mbuf *) crp->crp_buf;
538 	xd = (struct xform_data *) crp->crp_opaque;
539 	CURVNET_SET(xd->vnet);
540 	idx = xd->idx;
541 	sp = xd->sp;
542 	sav = xd->sav;
543 	skip = xd->skip;
544 	protoff = xd->protoff;
545 	cryptoid = xd->cryptoid;
546 
547 	/* Check for crypto errors */
548 	if (crp->crp_etype) {
549 		if (crp->crp_etype == EAGAIN) {
550 			/* Reset the session ID */
551 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
552 				crypto_freesession(cryptoid);
553 			xd->cryptoid = crp->crp_session;
554 			CURVNET_RESTORE();
555 			return (crypto_dispatch(crp));
556 		}
557 		IPCOMPSTAT_INC(ipcomps_noxform);
558 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
559 		error = crp->crp_etype;
560 		goto bad;
561 	}
562 	/* Shouldn't happen... */
563 	if (m == NULL) {
564 		IPCOMPSTAT_INC(ipcomps_crypto);
565 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
566 		error = EINVAL;
567 		goto bad;
568 	}
569 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
570 
571 	if (crp->crp_ilen - skip > crp->crp_olen) {
572 		struct mbuf *mo;
573 		struct ipcomp *ipcomp;
574 		int roff;
575 		uint8_t prot;
576 
577 		/* Compression helped, inject IPCOMP header. */
578 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
579 		if (mo == NULL) {
580 			IPCOMPSTAT_INC(ipcomps_wrap);
581 			DPRINTF(("%s: IPCOMP header inject failed "
582 			    "for IPCA %s/%08lx\n",
583 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
584 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
585 			error = ENOBUFS;
586 			goto bad;
587 		}
588 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + 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 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
606 
607 		/* Fix Next Protocol in IPv4/IPv6 header */
608 		prot = IPPROTO_IPCOMP;
609 		m_copyback(m, protoff, sizeof(u_int8_t),
610 		    (u_char *)&prot);
611 
612 		/* Adjust the length in the IP header */
613 		switch (sav->sah->saidx.dst.sa.sa_family) {
614 #ifdef INET
615 		case AF_INET:
616 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
617 			break;
618 #endif /* INET */
619 #ifdef INET6
620 		case AF_INET6:
621 			mtod(m, struct ip6_hdr *)->ip6_plen =
622 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
623 			break;
624 #endif /* INET6 */
625 		default:
626 			IPCOMPSTAT_INC(ipcomps_nopf);
627 			DPRINTF(("%s: unknown/unsupported protocol "
628 			    "family %d, IPCA %s/%08lx\n", __func__,
629 			    sav->sah->saidx.dst.sa.sa_family,
630 			    ipsec_address(&sav->sah->saidx.dst, buf,
631 				sizeof(buf)), (u_long) ntohl(sav->spi)));
632 			error = EPFNOSUPPORT;
633 			goto bad;
634 		}
635 	} else {
636 		/* Compression was useless, we have lost time. */
637 		IPCOMPSTAT_INC(ipcomps_uncompr);
638 		DPRINTF(("%s: compressions was useless %d - %d <= %d\n",
639 		    __func__, crp->crp_ilen, skip, crp->crp_olen));
640 		/* XXX remember state to not compress the next couple
641 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
642 	}
643 
644 	/* Release the crypto descriptor */
645 	free(xd, M_XDATA);
646 	crypto_freereq(crp);
647 
648 	/* NB: m is reclaimed by ipsec_process_done. */
649 	error = ipsec_process_done(m, sp, sav, idx);
650 	CURVNET_RESTORE();
651 	return (error);
652 bad:
653 	if (m)
654 		m_freem(m);
655 	CURVNET_RESTORE();
656 	free(xd, M_XDATA);
657 	crypto_freereq(crp);
658 	key_freesav(&sav);
659 	key_freesp(&sp);
660 	return (error);
661 }
662 
663 #ifdef INET
664 static int
665 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
666     void *arg __unused)
667 {
668 	union sockaddr_union src, dst;
669 	const struct ip *ip;
670 
671 	if (V_ipcomp_enable == 0)
672 		return (0);
673 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
674 		return (0);
675 	bzero(&src, sizeof(src));
676 	bzero(&dst, sizeof(dst));
677 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
678 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
679 	ip = mtod(m, const struct ip *);
680 	src.sin.sin_addr = ip->ip_src;
681 	dst.sin.sin_addr = ip->ip_dst;
682 	return (ipcomp_encapcheck(&src, &dst));
683 }
684 
685 static const struct encaptab *ipe4_cookie = NULL;
686 static const struct encap_config ipv4_encap_cfg = {
687 	.proto = -1,
688 	.min_length = sizeof(struct ip),
689 	.exact_match = sizeof(in_addr_t) << 4,
690 	.check = ipcomp4_nonexp_encapcheck,
691 	.input = ipcomp_nonexp_input
692 };
693 #endif
694 #ifdef INET6
695 static int
696 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
697     void *arg __unused)
698 {
699 	union sockaddr_union src, dst;
700 	const struct ip6_hdr *ip6;
701 
702 	if (V_ipcomp_enable == 0)
703 		return (0);
704 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
705 		return (0);
706 	bzero(&src, sizeof(src));
707 	bzero(&dst, sizeof(dst));
708 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
709 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
710 	ip6 = mtod(m, const struct ip6_hdr *);
711 	src.sin6.sin6_addr = ip6->ip6_src;
712 	dst.sin6.sin6_addr = ip6->ip6_dst;
713 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
714 		/* XXX: sa6_recoverscope() */
715 		src.sin6.sin6_scope_id =
716 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
717 		src.sin6.sin6_addr.s6_addr16[1] = 0;
718 	}
719 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
720 		/* XXX: sa6_recoverscope() */
721 		dst.sin6.sin6_scope_id =
722 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
723 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
724 	}
725 	return (ipcomp_encapcheck(&src, &dst));
726 }
727 
728 static const struct encaptab *ipe6_cookie = NULL;
729 static const struct encap_config ipv6_encap_cfg = {
730 	.proto = -1,
731 	.min_length = sizeof(struct ip6_hdr),
732 	.exact_match = sizeof(struct in6_addr) << 4,
733 	.check = ipcomp6_nonexp_encapcheck,
734 	.input = ipcomp_nonexp_input
735 };
736 #endif
737 
738 static struct xformsw ipcomp_xformsw = {
739 	.xf_type =	XF_IPCOMP,
740 	.xf_name =	"IPcomp",
741 	.xf_init =	ipcomp_init,
742 	.xf_zeroize =	ipcomp_zeroize,
743 	.xf_input =	ipcomp_input,
744 	.xf_output =	ipcomp_output,
745 };
746 
747 static void
748 ipcomp_attach(void)
749 {
750 
751 #ifdef INET
752 	ipe4_cookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
753 #endif
754 #ifdef INET6
755 	ipe6_cookie = ip6_encap_attach(&ipv6_encap_cfg, NULL, M_WAITOK);
756 #endif
757 	xform_attach(&ipcomp_xformsw);
758 }
759 
760 static void
761 ipcomp_detach(void)
762 {
763 
764 #ifdef INET
765 	ip_encap_detach(ipe4_cookie);
766 #endif
767 #ifdef INET6
768 	ip6_encap_detach(ipe6_cookie);
769 #endif
770 	xform_detach(&ipcomp_xformsw);
771 }
772 
773 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
774     ipcomp_attach, NULL);
775 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
776     ipcomp_detach, NULL);
777