xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
1 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
2 
3 /*-
4  * SPDX-License-Identifier: BSD-3-Clause
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 /* IP payload compression protocol (IPComp), see RFC 2393 */
33 #include "opt_inet.h"
34 #include "opt_inet6.h"
35 #include "opt_ipsec.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/mbuf.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/socket.h>
44 #include <sys/kernel.h>
45 #include <sys/protosw.h>
46 #include <sys/sysctl.h>
47 
48 #include <netinet/in.h>
49 #include <netinet/in_systm.h>
50 #include <netinet/ip.h>
51 #include <netinet/ip_var.h>
52 #include <netinet/ip_encap.h>
53 
54 #include <net/netisr.h>
55 #include <net/vnet.h>
56 #include <net/if.h>	/* XXXGL: net_epoch should move out there */
57 #include <net/if_var.h>	/* XXXGL: net_epoch should move out there */
58 
59 #include <netipsec/ipsec.h>
60 #include <netipsec/xform.h>
61 
62 #ifdef INET6
63 #include <netinet/ip6.h>
64 #include <netinet6/ip6_var.h>
65 #include <netipsec/ipsec6.h>
66 #endif
67 
68 #include <netipsec/ipcomp.h>
69 #include <netipsec/ipcomp_var.h>
70 
71 #include <netipsec/key.h>
72 #include <netipsec/key_debug.h>
73 
74 #include <opencrypto/cryptodev.h>
75 #include <opencrypto/deflate.h>
76 #include <opencrypto/xform.h>
77 
78 VNET_DEFINE(int, ipcomp_enable) = 1;
79 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
80 VNET_PCPUSTAT_SYSINIT(ipcompstat);
81 
82 #ifdef VIMAGE
83 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
84 #endif /* VIMAGE */
85 
86 SYSCTL_DECL(_net_inet_ipcomp);
87 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
88 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
89 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
90     struct ipcompstat, ipcompstat,
91     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
92 
93 static MALLOC_DEFINE(M_IPCOMP, "ipcomp", "IPCOMP");
94 
95 static int ipcomp_input_cb(struct cryptop *crp);
96 static int ipcomp_output_cb(struct cryptop *crp);
97 
98 /*
99  * RFC 3173 p 2.2. Non-Expansion Policy:
100  * If the total size of a compressed payload and the IPComp header, as
101  * defined in section 3, is not smaller than the size of the original
102  * payload, the IP datagram MUST be sent in the original non-compressed
103  * form.
104  *
105  * When we use IPComp in tunnel mode, for small packets we will receive
106  * encapsulated IP-IP datagrams without any compression and without IPComp
107  * header.
108  */
109 static int
110 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
111 {
112 	struct secasvar *sav;
113 
114 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
115 	if (sav == NULL)
116 		return (0);
117 	key_freesav(&sav);
118 
119 	if (src->sa.sa_family == AF_INET)
120 		return (sizeof(struct in_addr) << 4);
121 	else
122 		return (sizeof(struct in6_addr) << 4);
123 }
124 
125 static int
126 ipcomp_nonexp_input(struct mbuf *m, int off, int proto, void *arg __unused)
127 {
128 	int isr;
129 
130 	NET_EPOCH_ASSERT();
131 
132 	switch (proto) {
133 #ifdef INET
134 	case IPPROTO_IPV4:
135 		isr = NETISR_IP;
136 		break;
137 #endif
138 #ifdef INET6
139 	case IPPROTO_IPV6:
140 		isr = NETISR_IPV6;
141 		break;
142 #endif
143 	default:
144 		IPCOMPSTAT_INC(ipcomps_nopf);
145 		m_freem(m);
146 		return (IPPROTO_DONE);
147 	}
148 	m_adj(m, off);
149 	IPCOMPSTAT_ADD(ipcomps_ibytes, m->m_pkthdr.len);
150 	IPCOMPSTAT_INC(ipcomps_input);
151 	netisr_dispatch(isr, m);
152 	return (IPPROTO_DONE);
153 }
154 
155 /*
156  * ipcomp_init() is called when an CPI is being set up.
157  */
158 static int
159 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
160 {
161 	const struct comp_algo *tcomp;
162 	struct crypto_session_params csp;
163 
164 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
165 	tcomp = comp_algorithm_lookup(sav->alg_enc);
166 	if (tcomp == NULL) {
167 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
168 			 sav->alg_comp));
169 		return EINVAL;
170 	}
171 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
172 	sav->tdb_xform = xsp;
173 	sav->tdb_compalgxform = tcomp;
174 
175 	/* Initialize crypto session */
176 	memset(&csp, 0, sizeof(csp));
177 	csp.csp_mode = CSP_MODE_COMPRESS;
178 	csp.csp_cipher_alg = sav->tdb_compalgxform->type;
179 
180 	return crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
181 }
182 
183 /*
184  * ipcomp_cleanup() used when IPCA is deleted
185  */
186 static void
187 ipcomp_cleanup(struct secasvar *sav)
188 {
189 
190 	crypto_freesession(sav->tdb_cryptoid);
191 	sav->tdb_cryptoid = NULL;
192 }
193 
194 /*
195  * ipcomp_input() gets called to uncompress an input packet
196  */
197 static int
198 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
199 {
200 	struct xform_data *xd;
201 	struct cryptop *crp;
202 	struct ipcomp *ipcomp;
203 	crypto_session_t cryptoid;
204 	caddr_t addr;
205 	int error, hlen = IPCOMP_HLENGTH;
206 
207 	SECASVAR_RLOCK_TRACKER;
208 
209 	/*
210 	 * Check that the next header of the IPComp is not IPComp again, before
211 	 * doing any real work.  Given it is not possible to do double
212 	 * compression it means someone is playing tricks on us.
213 	 */
214 	error = ENOBUFS;
215 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
216 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
217 		DPRINTF(("%s: m_pullup failed\n", __func__));
218 		key_freesav(&sav);
219 		return (error);
220 	}
221 	addr = (caddr_t) mtod(m, struct ip *) + skip;
222 	ipcomp = (struct ipcomp *)addr;
223 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
224 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
225 		DPRINTF(("%s: recursive compression detected\n", __func__));
226 		error = EINVAL;
227 		goto bad;
228 	}
229 
230 	SECASVAR_RLOCK(sav);
231 	cryptoid = sav->tdb_cryptoid;
232 	SECASVAR_RUNLOCK(sav);
233 
234 	/* Get crypto descriptors */
235 	crp = crypto_getreq(cryptoid, M_NOWAIT);
236 	if (crp == NULL) {
237 		DPRINTF(("%s: no crypto descriptors\n", __func__));
238 		IPCOMPSTAT_INC(ipcomps_crypto);
239 		goto bad;
240 	}
241 	/* Get IPsec-specific opaque pointer */
242 	xd = malloc(sizeof(*xd), M_IPCOMP, M_NOWAIT | M_ZERO);
243 	if (xd == NULL) {
244 		DPRINTF(("%s: cannot allocate xform_data\n", __func__));
245 		IPCOMPSTAT_INC(ipcomps_crypto);
246 		crypto_freereq(crp);
247 		goto bad;
248 	}
249 
250 	/* Decompression operation */
251 	crp->crp_op = CRYPTO_OP_DECOMPRESS;
252 	crp->crp_payload_start = skip + hlen;
253 	crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen);
254 
255 	/* Crypto operation descriptor */
256 	crp->crp_flags = CRYPTO_F_CBIFSYNC;
257 	crypto_use_mbuf(crp, m);
258 	crp->crp_callback = ipcomp_input_cb;
259 	crp->crp_opaque = xd;
260 
261 	/* These are passed as-is to the callback */
262 	xd->sav = sav;
263 	xd->protoff = protoff;
264 	xd->skip = skip;
265 	xd->vnet = curvnet;
266 	xd->cryptoid = cryptoid;
267 
268 	SECASVAR_RLOCK(sav);
269 	crp->crp_session = xd->cryptoid = sav->tdb_cryptoid;
270 	SECASVAR_RUNLOCK(sav);
271 
272 	return crypto_dispatch(crp);
273 bad:
274 	m_freem(m);
275 	key_freesav(&sav);
276 	return (error);
277 }
278 
279 /*
280  * IPComp input callback from the crypto driver.
281  */
282 static int
283 ipcomp_input_cb(struct cryptop *crp)
284 {
285 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
286 	struct xform_data *xd;
287 	struct mbuf *m;
288 	struct secasvar *sav;
289 	struct secasindex *saidx;
290 	caddr_t addr;
291 	crypto_session_t cryptoid;
292 	int hlen = IPCOMP_HLENGTH, error, clen;
293 	int skip, protoff;
294 	uint8_t nproto;
295 
296 	m = crp->crp_buf.cb_mbuf;
297 	xd = crp->crp_opaque;
298 	CURVNET_SET(xd->vnet);
299 	sav = xd->sav;
300 	skip = xd->skip;
301 	protoff = xd->protoff;
302 	cryptoid = xd->cryptoid;
303 	saidx = &sav->sah->saidx;
304 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
305 		saidx->dst.sa.sa_family == AF_INET6,
306 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
307 
308 	/* Check for crypto errors */
309 	if (crp->crp_etype) {
310 		if (crp->crp_etype == EAGAIN) {
311 			/* Reset the session ID */
312 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
313 				crypto_freesession(cryptoid);
314 			xd->cryptoid = crp->crp_session;
315 			CURVNET_RESTORE();
316 			return (crypto_dispatch(crp));
317 		}
318 		IPCOMPSTAT_INC(ipcomps_noxform);
319 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
320 		error = crp->crp_etype;
321 		goto bad;
322 	}
323 	/* Shouldn't happen... */
324 	if (m == NULL) {
325 		IPCOMPSTAT_INC(ipcomps_crypto);
326 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
327 		error = EINVAL;
328 		goto bad;
329 	}
330 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
331 
332 	clen = crp->crp_olen;		/* Length of data after processing */
333 
334 	/* Release the crypto descriptors */
335 	free(xd, M_IPCOMP), xd = NULL;
336 	crypto_freereq(crp), crp = NULL;
337 
338 	/* In case it's not done already, adjust the size of the mbuf chain */
339 	m->m_pkthdr.len = clen + hlen + skip;
340 
341 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
342 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
343 		DPRINTF(("%s: m_pullup failed\n", __func__));
344 		error = EINVAL;				/*XXX*/
345 		goto bad;
346 	}
347 
348 	/* Keep the next protocol field */
349 	addr = (caddr_t) mtod(m, struct ip *) + skip;
350 	nproto = ((struct ipcomp *) addr)->comp_nxt;
351 
352 	/* Remove the IPCOMP header */
353 	error = m_striphdr(m, skip, hlen);
354 	if (error) {
355 		IPCOMPSTAT_INC(ipcomps_hdrops);
356 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
357 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
358 		    (u_long) ntohl(sav->spi)));
359 		goto bad;
360 	}
361 
362 	/* Restore the Next Protocol field */
363 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
364 
365 	switch (saidx->dst.sa.sa_family) {
366 #ifdef INET6
367 	case AF_INET6:
368 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
369 		break;
370 #endif
371 #ifdef INET
372 	case AF_INET:
373 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
374 		break;
375 #endif
376 	default:
377 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
378 		    saidx->dst.sa.sa_family, saidx);
379 	}
380 	CURVNET_RESTORE();
381 	return error;
382 bad:
383 	CURVNET_RESTORE();
384 	if (sav != NULL)
385 		key_freesav(&sav);
386 	if (m != NULL)
387 		m_freem(m);
388 	if (xd != NULL)
389 		free(xd, M_IPCOMP);
390 	if (crp != NULL)
391 		crypto_freereq(crp);
392 	return error;
393 }
394 
395 /*
396  * IPComp output routine, called by ipsec[46]_perform_request()
397  */
398 static int
399 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
400     u_int idx, int skip, int protoff)
401 {
402 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
403 	const struct comp_algo *ipcompx;
404 	struct cryptop *crp;
405 	struct xform_data *xd;
406 	crypto_session_t cryptoid;
407 	int error, ralen, maxpacketsize;
408 
409 	SECASVAR_RLOCK_TRACKER;
410 
411 	IPSEC_ASSERT(sav != NULL, ("null SA"));
412 	ipcompx = sav->tdb_compalgxform;
413 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
414 
415 	/*
416 	 * Do not touch the packet in case our payload to compress
417 	 * is lower than the minimal threshold of the compression
418 	 * alogrithm.  We will just send out the data uncompressed.
419 	 * See RFC 3173, 2.2. Non-Expansion Policy.
420 	 */
421 	if (m->m_pkthdr.len <= ipcompx->minlen) {
422 		IPCOMPSTAT_INC(ipcomps_threshold);
423 		return ipsec_process_done(m, sp, sav, idx);
424 	}
425 
426 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
427 	IPCOMPSTAT_INC(ipcomps_output);
428 
429 	/* Check for maximum packet size violations. */
430 	switch (sav->sah->saidx.dst.sa.sa_family) {
431 #ifdef INET
432 	case AF_INET:
433 		maxpacketsize = IP_MAXPACKET;
434 		break;
435 #endif /* INET */
436 #ifdef INET6
437 	case AF_INET6:
438 		maxpacketsize = IPV6_MAXPACKET;
439 		break;
440 #endif /* INET6 */
441 	default:
442 		IPCOMPSTAT_INC(ipcomps_nopf);
443 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
444 		    "IPCA %s/%08lx\n", __func__,
445 		    sav->sah->saidx.dst.sa.sa_family,
446 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
447 		    (u_long) ntohl(sav->spi)));
448 		error = EPFNOSUPPORT;
449 		goto bad;
450 	}
451 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
452 		IPCOMPSTAT_INC(ipcomps_toobig);
453 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
454 		    "(len %u, max len %u)\n", __func__,
455 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
456 		    (u_long) ntohl(sav->spi),
457 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
458 		error = EMSGSIZE;
459 		goto bad;
460 	}
461 
462 	/* Update the counters */
463 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
464 
465 	m = m_unshare(m, M_NOWAIT);
466 	if (m == NULL) {
467 		IPCOMPSTAT_INC(ipcomps_hdrops);
468 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
469 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
470 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
471 		error = ENOBUFS;
472 		goto bad;
473 	}
474 
475 	/* Ok now, we can pass to the crypto processing. */
476 	SECASVAR_RLOCK(sav);
477 	cryptoid = sav->tdb_cryptoid;
478 	SECASVAR_RUNLOCK(sav);
479 
480 	/* Get crypto descriptors */
481 	crp = crypto_getreq(cryptoid, M_NOWAIT);
482 	if (crp == NULL) {
483 		IPCOMPSTAT_INC(ipcomps_crypto);
484 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
485 		error = ENOBUFS;
486 		goto bad;
487 	}
488 
489 	/* Compression descriptor */
490 	crp->crp_op = CRYPTO_OP_COMPRESS;
491 	crp->crp_payload_start = skip;
492 	crp->crp_payload_length = ralen;
493 
494 	/* IPsec-specific opaque crypto info */
495 	xd =  malloc(sizeof(struct xform_data), M_IPCOMP, M_NOWAIT | M_ZERO);
496 	if (xd == NULL) {
497 		IPCOMPSTAT_INC(ipcomps_crypto);
498 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
499 		crypto_freereq(crp);
500 		error = ENOBUFS;
501 		goto bad;
502 	}
503 
504 	xd->sp = sp;
505 	xd->sav = sav;
506 	xd->idx = idx;
507 	xd->skip = skip;
508 	xd->protoff = protoff;
509 	xd->vnet = curvnet;
510 	xd->cryptoid = cryptoid;
511 
512 	/* Crypto operation descriptor */
513 	crp->crp_flags = CRYPTO_F_CBIFSYNC;
514 	crypto_use_mbuf(crp, m);
515 	crp->crp_callback = ipcomp_output_cb;
516 	crp->crp_opaque = xd;
517 
518 	return crypto_dispatch(crp);
519 bad:
520 	if (m)
521 		m_freem(m);
522 	key_freesav(&sav);
523 	key_freesp(&sp);
524 	return (error);
525 }
526 
527 /*
528  * IPComp output callback from the crypto driver.
529  */
530 static int
531 ipcomp_output_cb(struct cryptop *crp)
532 {
533 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
534 	struct xform_data *xd;
535 	struct secpolicy *sp;
536 	struct secasvar *sav;
537 	struct mbuf *m;
538 	crypto_session_t cryptoid;
539 	u_int idx;
540 	int error, skip, protoff;
541 
542 	m = crp->crp_buf.cb_mbuf;
543 	xd = crp->crp_opaque;
544 	CURVNET_SET(xd->vnet);
545 	idx = xd->idx;
546 	sp = xd->sp;
547 	sav = xd->sav;
548 	skip = xd->skip;
549 	protoff = xd->protoff;
550 	cryptoid = xd->cryptoid;
551 
552 	/* Check for crypto errors */
553 	if (crp->crp_etype) {
554 		if (crp->crp_etype == EAGAIN) {
555 			/* Reset the session ID */
556 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
557 				crypto_freesession(cryptoid);
558 			xd->cryptoid = crp->crp_session;
559 			CURVNET_RESTORE();
560 			return (crypto_dispatch(crp));
561 		}
562 		IPCOMPSTAT_INC(ipcomps_noxform);
563 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
564 		error = crp->crp_etype;
565 		goto bad;
566 	}
567 	/* Shouldn't happen... */
568 	if (m == NULL) {
569 		IPCOMPSTAT_INC(ipcomps_crypto);
570 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
571 		error = EINVAL;
572 		goto bad;
573 	}
574 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
575 
576 	if (crp->crp_payload_length > crp->crp_olen) {
577 		struct mbuf *mo;
578 		struct ipcomp *ipcomp;
579 		int roff;
580 		uint8_t prot;
581 
582 		/* Compression helped, inject IPCOMP header. */
583 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
584 		if (mo == NULL) {
585 			IPCOMPSTAT_INC(ipcomps_wrap);
586 			DPRINTF(("%s: IPCOMP header inject failed "
587 			    "for IPCA %s/%08lx\n",
588 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
589 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
590 			error = ENOBUFS;
591 			goto bad;
592 		}
593 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
594 
595 		/* Initialize the IPCOMP header */
596 		/* XXX alignment always correct? */
597 		switch (sav->sah->saidx.dst.sa.sa_family) {
598 #ifdef INET
599 		case AF_INET:
600 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
601 			break;
602 #endif /* INET */
603 #ifdef INET6
604 		case AF_INET6:
605 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
606 			break;
607 #endif
608 		}
609 		ipcomp->comp_flags = 0;
610 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
611 
612 		/* Fix Next Protocol in IPv4/IPv6 header */
613 		prot = IPPROTO_IPCOMP;
614 		m_copyback(m, protoff, sizeof(u_int8_t),
615 		    (u_char *)&prot);
616 
617 		/* Adjust the length in the IP header */
618 		switch (sav->sah->saidx.dst.sa.sa_family) {
619 #ifdef INET
620 		case AF_INET:
621 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
622 			break;
623 #endif /* INET */
624 #ifdef INET6
625 		case AF_INET6:
626 			mtod(m, struct ip6_hdr *)->ip6_plen =
627 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
628 			break;
629 #endif /* INET6 */
630 		default:
631 			IPCOMPSTAT_INC(ipcomps_nopf);
632 			DPRINTF(("%s: unknown/unsupported protocol "
633 			    "family %d, IPCA %s/%08lx\n", __func__,
634 			    sav->sah->saidx.dst.sa.sa_family,
635 			    ipsec_address(&sav->sah->saidx.dst, buf,
636 				sizeof(buf)), (u_long) ntohl(sav->spi)));
637 			error = EPFNOSUPPORT;
638 			goto bad;
639 		}
640 	} else {
641 		/* Compression was useless, we have lost time. */
642 		IPCOMPSTAT_INC(ipcomps_uncompr);
643 		DPRINTF(("%s: compressions was useless %d <= %d\n",
644 		    __func__, crp->crp_payload_length, crp->crp_olen));
645 		/* XXX remember state to not compress the next couple
646 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
647 	}
648 
649 	/* Release the crypto descriptor */
650 	free(xd, M_IPCOMP);
651 	crypto_freereq(crp);
652 
653 	/* NB: m is reclaimed by ipsec_process_done. */
654 	error = ipsec_process_done(m, sp, sav, idx);
655 	CURVNET_RESTORE();
656 	return (error);
657 bad:
658 	if (m)
659 		m_freem(m);
660 	CURVNET_RESTORE();
661 	free(xd, M_IPCOMP);
662 	crypto_freereq(crp);
663 	key_freesav(&sav);
664 	key_freesp(&sp);
665 	return (error);
666 }
667 
668 #ifdef INET
669 static int
670 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
671     void *arg __unused)
672 {
673 	union sockaddr_union src, dst;
674 	const struct ip *ip;
675 
676 	if (V_ipcomp_enable == 0)
677 		return (0);
678 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
679 		return (0);
680 	bzero(&src, sizeof(src));
681 	bzero(&dst, sizeof(dst));
682 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
683 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
684 	ip = mtod(m, const struct ip *);
685 	src.sin.sin_addr = ip->ip_src;
686 	dst.sin.sin_addr = ip->ip_dst;
687 	return (ipcomp_encapcheck(&src, &dst));
688 }
689 
690 static const struct encaptab *ipe4_cookie = NULL;
691 static const struct encap_config ipv4_encap_cfg = {
692 	.proto = -1,
693 	.min_length = sizeof(struct ip),
694 	.exact_match = sizeof(in_addr_t) << 4,
695 	.check = ipcomp4_nonexp_encapcheck,
696 	.input = ipcomp_nonexp_input
697 };
698 #endif
699 #ifdef INET6
700 static int
701 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
702     void *arg __unused)
703 {
704 	union sockaddr_union src, dst;
705 	const struct ip6_hdr *ip6;
706 
707 	if (V_ipcomp_enable == 0)
708 		return (0);
709 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
710 		return (0);
711 	bzero(&src, sizeof(src));
712 	bzero(&dst, sizeof(dst));
713 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
714 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
715 	ip6 = mtod(m, const struct ip6_hdr *);
716 	src.sin6.sin6_addr = ip6->ip6_src;
717 	dst.sin6.sin6_addr = ip6->ip6_dst;
718 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
719 		/* XXX: sa6_recoverscope() */
720 		src.sin6.sin6_scope_id =
721 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
722 		src.sin6.sin6_addr.s6_addr16[1] = 0;
723 	}
724 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
725 		/* XXX: sa6_recoverscope() */
726 		dst.sin6.sin6_scope_id =
727 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
728 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
729 	}
730 	return (ipcomp_encapcheck(&src, &dst));
731 }
732 
733 static const struct encaptab *ipe6_cookie = NULL;
734 static const struct encap_config ipv6_encap_cfg = {
735 	.proto = -1,
736 	.min_length = sizeof(struct ip6_hdr),
737 	.exact_match = sizeof(struct in6_addr) << 4,
738 	.check = ipcomp6_nonexp_encapcheck,
739 	.input = ipcomp_nonexp_input
740 };
741 #endif
742 
743 static struct xformsw ipcomp_xformsw = {
744 	.xf_type =	XF_IPCOMP,
745 	.xf_name =	"IPcomp",
746 	.xf_init =	ipcomp_init,
747 	.xf_cleanup =	ipcomp_cleanup,
748 	.xf_input =	ipcomp_input,
749 	.xf_output =	ipcomp_output,
750 };
751 
752 static void
753 ipcomp_attach(void)
754 {
755 
756 #ifdef INET
757 	ipe4_cookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
758 #endif
759 #ifdef INET6
760 	ipe6_cookie = ip6_encap_attach(&ipv6_encap_cfg, NULL, M_WAITOK);
761 #endif
762 	xform_attach(&ipcomp_xformsw);
763 }
764 
765 static void
766 ipcomp_detach(void)
767 {
768 
769 #ifdef INET
770 	ip_encap_detach(ipe4_cookie);
771 #endif
772 #ifdef INET6
773 	ip6_encap_detach(ipe6_cookie);
774 #endif
775 	xform_detach(&ipcomp_xformsw);
776 }
777 
778 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
779     ipcomp_attach, NULL);
780 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
781     ipcomp_detach, NULL);
782