xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision 6f63e88c0166ed3e5f2805a9e667c7d24d304cf1)
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 #include <net/if.h>	/* XXXGL: net_epoch should move out there */
56 #include <net/if_var.h>	/* XXXGL: net_epoch should move out there */
57 
58 #include <netipsec/ipsec.h>
59 #include <netipsec/xform.h>
60 
61 #ifdef INET6
62 #include <netinet/ip6.h>
63 #include <netinet6/ip6_var.h>
64 #include <netipsec/ipsec6.h>
65 #endif
66 
67 #include <netipsec/ipcomp.h>
68 #include <netipsec/ipcomp_var.h>
69 
70 #include <netipsec/key.h>
71 #include <netipsec/key_debug.h>
72 
73 #include <opencrypto/cryptodev.h>
74 #include <opencrypto/deflate.h>
75 #include <opencrypto/xform.h>
76 
77 VNET_DEFINE(int, ipcomp_enable) = 1;
78 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
79 VNET_PCPUSTAT_SYSINIT(ipcompstat);
80 
81 #ifdef VIMAGE
82 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
83 #endif /* VIMAGE */
84 
85 SYSCTL_DECL(_net_inet_ipcomp);
86 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
87 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
88 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
89     struct ipcompstat, ipcompstat,
90     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
91 
92 static int ipcomp_input_cb(struct cryptop *crp);
93 static int ipcomp_output_cb(struct cryptop *crp);
94 
95 /*
96  * RFC 3173 p 2.2. Non-Expansion Policy:
97  * If the total size of a compressed payload and the IPComp header, as
98  * defined in section 3, is not smaller than the size of the original
99  * payload, the IP datagram MUST be sent in the original non-compressed
100  * form.
101  *
102  * When we use IPComp in tunnel mode, for small packets we will receive
103  * encapsulated IP-IP datagrams without any compression and without IPComp
104  * header.
105  */
106 static int
107 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
108 {
109 	struct secasvar *sav;
110 
111 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
112 	if (sav == NULL)
113 		return (0);
114 	key_freesav(&sav);
115 
116 	if (src->sa.sa_family == AF_INET)
117 		return (sizeof(struct in_addr) << 4);
118 	else
119 		return (sizeof(struct in6_addr) << 4);
120 }
121 
122 static int
123 ipcomp_nonexp_input(struct mbuf *m, int off, int proto, void *arg __unused)
124 {
125 	int isr;
126 
127 	NET_EPOCH_ASSERT();
128 
129 	switch (proto) {
130 #ifdef INET
131 	case IPPROTO_IPV4:
132 		isr = NETISR_IP;
133 		break;
134 #endif
135 #ifdef INET6
136 	case IPPROTO_IPV6:
137 		isr = NETISR_IPV6;
138 		break;
139 #endif
140 	default:
141 		IPCOMPSTAT_INC(ipcomps_nopf);
142 		m_freem(m);
143 		return (IPPROTO_DONE);
144 	}
145 	m_adj(m, off);
146 	IPCOMPSTAT_ADD(ipcomps_ibytes, m->m_pkthdr.len);
147 	IPCOMPSTAT_INC(ipcomps_input);
148 	netisr_dispatch(isr, m);
149 	return (IPPROTO_DONE);
150 }
151 
152 /*
153  * ipcomp_init() is called when an CPI is being set up.
154  */
155 static int
156 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
157 {
158 	const struct comp_algo *tcomp;
159 	struct crypto_session_params csp;
160 
161 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
162 	tcomp = comp_algorithm_lookup(sav->alg_enc);
163 	if (tcomp == NULL) {
164 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
165 			 sav->alg_comp));
166 		return EINVAL;
167 	}
168 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
169 	sav->tdb_xform = xsp;
170 	sav->tdb_compalgxform = tcomp;
171 
172 	/* Initialize crypto session */
173 	memset(&csp, 0, sizeof(csp));
174 	csp.csp_mode = CSP_MODE_COMPRESS;
175 	csp.csp_cipher_alg = sav->tdb_compalgxform->type;
176 
177 	return crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
178 }
179 
180 /*
181  * ipcomp_zeroize() used when IPCA is deleted
182  */
183 static int
184 ipcomp_zeroize(struct secasvar *sav)
185 {
186 
187 	crypto_freesession(sav->tdb_cryptoid);
188 	sav->tdb_cryptoid = NULL;
189 	return 0;
190 }
191 
192 /*
193  * ipcomp_input() gets called to uncompress an input packet
194  */
195 static int
196 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
197 {
198 	struct xform_data *xd;
199 	struct cryptop *crp;
200 	struct ipcomp *ipcomp;
201 	crypto_session_t cryptoid;
202 	caddr_t addr;
203 	int error, hlen = IPCOMP_HLENGTH;
204 
205 	/*
206 	 * Check that the next header of the IPComp is not IPComp again, before
207 	 * doing any real work.  Given it is not possible to do double
208 	 * compression it means someone is playing tricks on us.
209 	 */
210 	error = ENOBUFS;
211 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
212 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
213 		DPRINTF(("%s: m_pullup failed\n", __func__));
214 		key_freesav(&sav);
215 		return (error);
216 	}
217 	addr = (caddr_t) mtod(m, struct ip *) + skip;
218 	ipcomp = (struct ipcomp *)addr;
219 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
220 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
221 		DPRINTF(("%s: recursive compression detected\n", __func__));
222 		error = EINVAL;
223 		goto bad;
224 	}
225 
226 	SECASVAR_LOCK(sav);
227 	cryptoid = sav->tdb_cryptoid;
228 	SECASVAR_UNLOCK(sav);
229 
230 	/* Get crypto descriptors */
231 	crp = crypto_getreq(cryptoid, M_NOWAIT);
232 	if (crp == NULL) {
233 		DPRINTF(("%s: no crypto descriptors\n", __func__));
234 		IPCOMPSTAT_INC(ipcomps_crypto);
235 		goto bad;
236 	}
237 	/* Get IPsec-specific opaque pointer */
238 	xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
239 	if (xd == NULL) {
240 		DPRINTF(("%s: cannot allocate xform_data\n", __func__));
241 		IPCOMPSTAT_INC(ipcomps_crypto);
242 		crypto_freereq(crp);
243 		goto bad;
244 	}
245 
246 	/* Decompression operation */
247 	crp->crp_op = CRYPTO_OP_DECOMPRESS;
248 	crp->crp_payload_start = skip + hlen;
249 	crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen);
250 
251 	/* Crypto operation descriptor */
252 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
253 	crp->crp_flags = CRYPTO_F_CBIFSYNC;
254 	crp->crp_mbuf = m;
255 	crp->crp_buf_type = CRYPTO_BUF_MBUF;
256 	crp->crp_callback = ipcomp_input_cb;
257 	crp->crp_opaque = xd;
258 
259 	/* These are passed as-is to the callback */
260 	xd->sav = sav;
261 	xd->protoff = protoff;
262 	xd->skip = skip;
263 	xd->vnet = curvnet;
264 	xd->cryptoid = cryptoid;
265 
266 	SECASVAR_LOCK(sav);
267 	crp->crp_session = xd->cryptoid = sav->tdb_cryptoid;
268 	SECASVAR_UNLOCK(sav);
269 
270 	return crypto_dispatch(crp);
271 bad:
272 	m_freem(m);
273 	key_freesav(&sav);
274 	return (error);
275 }
276 
277 /*
278  * IPComp input callback from the crypto driver.
279  */
280 static int
281 ipcomp_input_cb(struct cryptop *crp)
282 {
283 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
284 	struct xform_data *xd;
285 	struct mbuf *m;
286 	struct secasvar *sav;
287 	struct secasindex *saidx;
288 	caddr_t addr;
289 	crypto_session_t cryptoid;
290 	int hlen = IPCOMP_HLENGTH, error, clen;
291 	int skip, protoff;
292 	uint8_t nproto;
293 
294 	m = crp->crp_mbuf;
295 	xd = crp->crp_opaque;
296 	CURVNET_SET(xd->vnet);
297 	sav = xd->sav;
298 	skip = xd->skip;
299 	protoff = xd->protoff;
300 	cryptoid = xd->cryptoid;
301 	saidx = &sav->sah->saidx;
302 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
303 		saidx->dst.sa.sa_family == AF_INET6,
304 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
305 
306 	/* Check for crypto errors */
307 	if (crp->crp_etype) {
308 		if (crp->crp_etype == EAGAIN) {
309 			/* Reset the session ID */
310 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
311 				crypto_freesession(cryptoid);
312 			xd->cryptoid = crp->crp_session;
313 			CURVNET_RESTORE();
314 			return (crypto_dispatch(crp));
315 		}
316 		IPCOMPSTAT_INC(ipcomps_noxform);
317 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
318 		error = crp->crp_etype;
319 		goto bad;
320 	}
321 	/* Shouldn't happen... */
322 	if (m == NULL) {
323 		IPCOMPSTAT_INC(ipcomps_crypto);
324 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
325 		error = EINVAL;
326 		goto bad;
327 	}
328 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
329 
330 	clen = crp->crp_olen;		/* Length of data after processing */
331 
332 	/* Release the crypto descriptors */
333 	free(xd, M_XDATA), xd = NULL;
334 	crypto_freereq(crp), crp = NULL;
335 
336 	/* In case it's not done already, adjust the size of the mbuf chain */
337 	m->m_pkthdr.len = clen + hlen + skip;
338 
339 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
340 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
341 		DPRINTF(("%s: m_pullup failed\n", __func__));
342 		error = EINVAL;				/*XXX*/
343 		goto bad;
344 	}
345 
346 	/* Keep the next protocol field */
347 	addr = (caddr_t) mtod(m, struct ip *) + skip;
348 	nproto = ((struct ipcomp *) addr)->comp_nxt;
349 
350 	/* Remove the IPCOMP header */
351 	error = m_striphdr(m, skip, hlen);
352 	if (error) {
353 		IPCOMPSTAT_INC(ipcomps_hdrops);
354 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
355 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
356 		    (u_long) ntohl(sav->spi)));
357 		goto bad;
358 	}
359 
360 	/* Restore the Next Protocol field */
361 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
362 
363 	switch (saidx->dst.sa.sa_family) {
364 #ifdef INET6
365 	case AF_INET6:
366 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
367 		break;
368 #endif
369 #ifdef INET
370 	case AF_INET:
371 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
372 		break;
373 #endif
374 	default:
375 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
376 		    saidx->dst.sa.sa_family, saidx);
377 	}
378 	CURVNET_RESTORE();
379 	return error;
380 bad:
381 	CURVNET_RESTORE();
382 	if (sav != NULL)
383 		key_freesav(&sav);
384 	if (m != NULL)
385 		m_freem(m);
386 	if (xd != NULL)
387 		free(xd, M_XDATA);
388 	if (crp != NULL)
389 		crypto_freereq(crp);
390 	return error;
391 }
392 
393 /*
394  * IPComp output routine, called by ipsec[46]_perform_request()
395  */
396 static int
397 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
398     u_int idx, int skip, int protoff)
399 {
400 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
401 	const struct comp_algo *ipcompx;
402 	struct cryptop *crp;
403 	struct xform_data *xd;
404 	crypto_session_t cryptoid;
405 	int error, ralen, maxpacketsize;
406 
407 	IPSEC_ASSERT(sav != NULL, ("null SA"));
408 	ipcompx = sav->tdb_compalgxform;
409 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
410 
411 	/*
412 	 * Do not touch the packet in case our payload to compress
413 	 * is lower than the minimal threshold of the compression
414 	 * alogrithm.  We will just send out the data uncompressed.
415 	 * See RFC 3173, 2.2. Non-Expansion Policy.
416 	 */
417 	if (m->m_pkthdr.len <= ipcompx->minlen) {
418 		IPCOMPSTAT_INC(ipcomps_threshold);
419 		return ipsec_process_done(m, sp, sav, idx);
420 	}
421 
422 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
423 	IPCOMPSTAT_INC(ipcomps_output);
424 
425 	/* Check for maximum packet size violations. */
426 	switch (sav->sah->saidx.dst.sa.sa_family) {
427 #ifdef INET
428 	case AF_INET:
429 		maxpacketsize = IP_MAXPACKET;
430 		break;
431 #endif /* INET */
432 #ifdef INET6
433 	case AF_INET6:
434 		maxpacketsize = IPV6_MAXPACKET;
435 		break;
436 #endif /* INET6 */
437 	default:
438 		IPCOMPSTAT_INC(ipcomps_nopf);
439 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
440 		    "IPCA %s/%08lx\n", __func__,
441 		    sav->sah->saidx.dst.sa.sa_family,
442 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
443 		    (u_long) ntohl(sav->spi)));
444 		error = EPFNOSUPPORT;
445 		goto bad;
446 	}
447 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
448 		IPCOMPSTAT_INC(ipcomps_toobig);
449 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
450 		    "(len %u, max len %u)\n", __func__,
451 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
452 		    (u_long) ntohl(sav->spi),
453 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
454 		error = EMSGSIZE;
455 		goto bad;
456 	}
457 
458 	/* Update the counters */
459 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
460 
461 	m = m_unshare(m, M_NOWAIT);
462 	if (m == NULL) {
463 		IPCOMPSTAT_INC(ipcomps_hdrops);
464 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
465 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
466 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
467 		error = ENOBUFS;
468 		goto bad;
469 	}
470 
471 	/* Ok now, we can pass to the crypto processing. */
472 	SECASVAR_LOCK(sav);
473 	cryptoid = sav->tdb_cryptoid;
474 	SECASVAR_UNLOCK(sav);
475 
476 	/* Get crypto descriptors */
477 	crp = crypto_getreq(cryptoid, M_NOWAIT);
478 	if (crp == NULL) {
479 		IPCOMPSTAT_INC(ipcomps_crypto);
480 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
481 		error = ENOBUFS;
482 		goto bad;
483 	}
484 
485 	/* Compression descriptor */
486 	crp->crp_op = CRYPTO_OP_COMPRESS;
487 	crp->crp_payload_start = skip;
488 	crp->crp_payload_length = ralen;
489 
490 	/* IPsec-specific opaque crypto info */
491 	xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
492 	if (xd == NULL) {
493 		IPCOMPSTAT_INC(ipcomps_crypto);
494 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
495 		crypto_freereq(crp);
496 		error = ENOBUFS;
497 		goto bad;
498 	}
499 
500 	xd->sp = sp;
501 	xd->sav = sav;
502 	xd->idx = idx;
503 	xd->skip = skip;
504 	xd->protoff = protoff;
505 	xd->vnet = curvnet;
506 	xd->cryptoid = cryptoid;
507 
508 	/* Crypto operation descriptor */
509 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
510 	crp->crp_flags = CRYPTO_F_CBIFSYNC;
511 	crp->crp_mbuf = m;
512 	crp->crp_buf_type = CRYPTO_BUF_MBUF;
513 	crp->crp_callback = ipcomp_output_cb;
514 	crp->crp_opaque = xd;
515 
516 	return crypto_dispatch(crp);
517 bad:
518 	if (m)
519 		m_freem(m);
520 	key_freesav(&sav);
521 	key_freesp(&sp);
522 	return (error);
523 }
524 
525 /*
526  * IPComp output callback from the crypto driver.
527  */
528 static int
529 ipcomp_output_cb(struct cryptop *crp)
530 {
531 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
532 	struct xform_data *xd;
533 	struct secpolicy *sp;
534 	struct secasvar *sav;
535 	struct mbuf *m;
536 	crypto_session_t cryptoid;
537 	u_int idx;
538 	int error, skip, protoff;
539 
540 	m = crp->crp_mbuf;
541 	xd = crp->crp_opaque;
542 	CURVNET_SET(xd->vnet);
543 	idx = xd->idx;
544 	sp = xd->sp;
545 	sav = xd->sav;
546 	skip = xd->skip;
547 	protoff = xd->protoff;
548 	cryptoid = xd->cryptoid;
549 
550 	/* Check for crypto errors */
551 	if (crp->crp_etype) {
552 		if (crp->crp_etype == EAGAIN) {
553 			/* Reset the session ID */
554 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
555 				crypto_freesession(cryptoid);
556 			xd->cryptoid = crp->crp_session;
557 			CURVNET_RESTORE();
558 			return (crypto_dispatch(crp));
559 		}
560 		IPCOMPSTAT_INC(ipcomps_noxform);
561 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
562 		error = crp->crp_etype;
563 		goto bad;
564 	}
565 	/* Shouldn't happen... */
566 	if (m == NULL) {
567 		IPCOMPSTAT_INC(ipcomps_crypto);
568 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
569 		error = EINVAL;
570 		goto bad;
571 	}
572 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
573 
574 	if (crp->crp_payload_length > crp->crp_olen) {
575 		struct mbuf *mo;
576 		struct ipcomp *ipcomp;
577 		int roff;
578 		uint8_t prot;
579 
580 		/* Compression helped, inject IPCOMP header. */
581 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
582 		if (mo == NULL) {
583 			IPCOMPSTAT_INC(ipcomps_wrap);
584 			DPRINTF(("%s: IPCOMP header inject failed "
585 			    "for IPCA %s/%08lx\n",
586 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
587 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
588 			error = ENOBUFS;
589 			goto bad;
590 		}
591 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
592 
593 		/* Initialize the IPCOMP header */
594 		/* XXX alignment always correct? */
595 		switch (sav->sah->saidx.dst.sa.sa_family) {
596 #ifdef INET
597 		case AF_INET:
598 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
599 			break;
600 #endif /* INET */
601 #ifdef INET6
602 		case AF_INET6:
603 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
604 			break;
605 #endif
606 		}
607 		ipcomp->comp_flags = 0;
608 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
609 
610 		/* Fix Next Protocol in IPv4/IPv6 header */
611 		prot = IPPROTO_IPCOMP;
612 		m_copyback(m, protoff, sizeof(u_int8_t),
613 		    (u_char *)&prot);
614 
615 		/* Adjust the length in the IP header */
616 		switch (sav->sah->saidx.dst.sa.sa_family) {
617 #ifdef INET
618 		case AF_INET:
619 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
620 			break;
621 #endif /* INET */
622 #ifdef INET6
623 		case AF_INET6:
624 			mtod(m, struct ip6_hdr *)->ip6_plen =
625 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
626 			break;
627 #endif /* INET6 */
628 		default:
629 			IPCOMPSTAT_INC(ipcomps_nopf);
630 			DPRINTF(("%s: unknown/unsupported protocol "
631 			    "family %d, IPCA %s/%08lx\n", __func__,
632 			    sav->sah->saidx.dst.sa.sa_family,
633 			    ipsec_address(&sav->sah->saidx.dst, buf,
634 				sizeof(buf)), (u_long) ntohl(sav->spi)));
635 			error = EPFNOSUPPORT;
636 			goto bad;
637 		}
638 	} else {
639 		/* Compression was useless, we have lost time. */
640 		IPCOMPSTAT_INC(ipcomps_uncompr);
641 		DPRINTF(("%s: compressions was useless %d <= %d\n",
642 		    __func__, crp->crp_payload_length, crp->crp_olen));
643 		/* XXX remember state to not compress the next couple
644 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
645 	}
646 
647 	/* Release the crypto descriptor */
648 	free(xd, M_XDATA);
649 	crypto_freereq(crp);
650 
651 	/* NB: m is reclaimed by ipsec_process_done. */
652 	error = ipsec_process_done(m, sp, sav, idx);
653 	CURVNET_RESTORE();
654 	return (error);
655 bad:
656 	if (m)
657 		m_freem(m);
658 	CURVNET_RESTORE();
659 	free(xd, M_XDATA);
660 	crypto_freereq(crp);
661 	key_freesav(&sav);
662 	key_freesp(&sp);
663 	return (error);
664 }
665 
666 #ifdef INET
667 static int
668 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
669     void *arg __unused)
670 {
671 	union sockaddr_union src, dst;
672 	const struct ip *ip;
673 
674 	if (V_ipcomp_enable == 0)
675 		return (0);
676 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
677 		return (0);
678 	bzero(&src, sizeof(src));
679 	bzero(&dst, sizeof(dst));
680 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
681 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
682 	ip = mtod(m, const struct ip *);
683 	src.sin.sin_addr = ip->ip_src;
684 	dst.sin.sin_addr = ip->ip_dst;
685 	return (ipcomp_encapcheck(&src, &dst));
686 }
687 
688 static const struct encaptab *ipe4_cookie = NULL;
689 static const struct encap_config ipv4_encap_cfg = {
690 	.proto = -1,
691 	.min_length = sizeof(struct ip),
692 	.exact_match = sizeof(in_addr_t) << 4,
693 	.check = ipcomp4_nonexp_encapcheck,
694 	.input = ipcomp_nonexp_input
695 };
696 #endif
697 #ifdef INET6
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 
731 static const struct encaptab *ipe6_cookie = NULL;
732 static const struct encap_config ipv6_encap_cfg = {
733 	.proto = -1,
734 	.min_length = sizeof(struct ip6_hdr),
735 	.exact_match = sizeof(struct in6_addr) << 4,
736 	.check = ipcomp6_nonexp_encapcheck,
737 	.input = ipcomp_nonexp_input
738 };
739 #endif
740 
741 static struct xformsw ipcomp_xformsw = {
742 	.xf_type =	XF_IPCOMP,
743 	.xf_name =	"IPcomp",
744 	.xf_init =	ipcomp_init,
745 	.xf_zeroize =	ipcomp_zeroize,
746 	.xf_input =	ipcomp_input,
747 	.xf_output =	ipcomp_output,
748 };
749 
750 static void
751 ipcomp_attach(void)
752 {
753 
754 #ifdef INET
755 	ipe4_cookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
756 #endif
757 #ifdef INET6
758 	ipe6_cookie = ip6_encap_attach(&ipv6_encap_cfg, NULL, M_WAITOK);
759 #endif
760 	xform_attach(&ipcomp_xformsw);
761 }
762 
763 static void
764 ipcomp_detach(void)
765 {
766 
767 #ifdef INET
768 	ip_encap_detach(ipe4_cookie);
769 #endif
770 #ifdef INET6
771 	ip6_encap_detach(ipe6_cookie);
772 #endif
773 	xform_detach(&ipcomp_xformsw);
774 }
775 
776 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
777     ipcomp_attach, NULL);
778 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
779     ipcomp_detach, NULL);
780