xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision 09a53ad8f1318c5daae6cfb19d97f4f6459f0013)
1 /*	$FreeBSD$	*/
2 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
3 
4 /*-
5  * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *   notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *   notice, this list of conditions and the following disclaimer in the
15  *   documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *   derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 /* IP payload compression protocol (IPComp), see RFC 2393 */
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/mbuf.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/rwlock.h>
41 #include <sys/socket.h>
42 #include <sys/kernel.h>
43 #include <sys/protosw.h>
44 #include <sys/sysctl.h>
45 
46 #include <netinet/in.h>
47 #include <netinet/in_systm.h>
48 #include <netinet/ip.h>
49 #include <netinet/ip_var.h>
50 #include <netinet/ip_encap.h>
51 
52 #include <net/netisr.h>
53 #include <net/vnet.h>
54 
55 #include <netipsec/ipsec.h>
56 #include <netipsec/xform.h>
57 
58 #ifdef INET6
59 #include <netinet/ip6.h>
60 #include <netinet6/ip6_var.h>
61 #include <netipsec/ipsec6.h>
62 #endif
63 
64 #include <netipsec/ipcomp.h>
65 #include <netipsec/ipcomp_var.h>
66 
67 #include <netipsec/key.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 struct comp_algo *
92 ipcomp_algorithm_lookup(int alg)
93 {
94 	if (alg >= IPCOMP_ALG_MAX)
95 		return NULL;
96 	switch (alg) {
97 	case SADB_X_CALG_DEFLATE:
98 		return &comp_algo_deflate;
99 	}
100 	return NULL;
101 }
102 
103 /*
104  * RFC 3173 p 2.2. Non-Expansion Policy:
105  * If the total size of a compressed payload and the IPComp header, as
106  * defined in section 3, is not smaller than the size of the original
107  * payload, the IP datagram MUST be sent in the original non-compressed
108  * form.
109  *
110  * When we use IPComp in tunnel mode, for small packets we will receive
111  * encapsulated IP-IP datagrams without any compression and without IPComp
112  * header.
113  */
114 static int
115 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
116 {
117 	struct secasvar *sav;
118 
119 	sav = KEY_ALLOCSA_TUNNEL(src, dst, IPPROTO_IPCOMP);
120 	if (sav == NULL)
121 		return (0);
122 	KEY_FREESAV(&sav);
123 
124 	if (src->sa.sa_family == AF_INET)
125 		return (sizeof(struct in_addr) << 4);
126 	else
127 		return (sizeof(struct in6_addr) << 4);
128 }
129 
130 static int
131 ipcomp_nonexp_input(struct mbuf **mp, int *offp, int proto)
132 {
133 	int isr;
134 
135 	switch (proto) {
136 #ifdef INET
137 	case IPPROTO_IPV4:
138 		isr = NETISR_IP;
139 		break;
140 #endif
141 #ifdef INET6
142 	case IPPROTO_IPV6:
143 		isr = NETISR_IPV6;
144 		break;
145 #endif
146 	default:
147 		IPCOMPSTAT_INC(ipcomps_nopf);
148 		m_freem(*mp);
149 		return (IPPROTO_DONE);
150 	}
151 	m_adj(*mp, *offp);
152 	IPCOMPSTAT_ADD(ipcomps_ibytes, (*mp)->m_pkthdr.len);
153 	IPCOMPSTAT_INC(ipcomps_input);
154 	netisr_dispatch(isr, *mp);
155 	return (IPPROTO_DONE);
156 }
157 
158 /*
159  * ipcomp_init() is called when an CPI is being set up.
160  */
161 static int
162 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
163 {
164 	struct comp_algo *tcomp;
165 	struct cryptoini cric;
166 
167 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
168 	tcomp = ipcomp_algorithm_lookup(sav->alg_enc);
169 	if (tcomp == NULL) {
170 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
171 			 sav->alg_comp));
172 		return EINVAL;
173 	}
174 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
175 	sav->tdb_xform = xsp;
176 	sav->tdb_compalgxform = tcomp;
177 
178 	/* Initialize crypto session */
179 	bzero(&cric, sizeof (cric));
180 	cric.cri_alg = sav->tdb_compalgxform->type;
181 
182 	return crypto_newsession(&sav->tdb_cryptoid, &cric, V_crypto_support);
183 }
184 
185 /*
186  * ipcomp_zeroize() used when IPCA is deleted
187  */
188 static int
189 ipcomp_zeroize(struct secasvar *sav)
190 {
191 	int err;
192 
193 	err = crypto_freesession(sav->tdb_cryptoid);
194 	sav->tdb_cryptoid = 0;
195 	return err;
196 }
197 
198 /*
199  * ipcomp_input() gets called to uncompress an input packet
200  */
201 static int
202 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
203 {
204 	struct tdb_crypto *tc;
205 	struct cryptodesc *crdc;
206 	struct cryptop *crp;
207 	struct ipcomp *ipcomp;
208 	caddr_t addr;
209 	int hlen = IPCOMP_HLENGTH;
210 
211 	/*
212 	 * Check that the next header of the IPComp is not IPComp again, before
213 	 * doing any real work.  Given it is not possible to do double
214 	 * compression it means someone is playing tricks on us.
215 	 */
216 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
217 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
218 		DPRINTF(("%s: m_pullup failed\n", __func__));
219 		return (ENOBUFS);
220 	}
221 	addr = (caddr_t) mtod(m, struct ip *) + skip;
222 	ipcomp = (struct ipcomp *)addr;
223 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
224 		m_freem(m);
225 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
226 		DPRINTF(("%s: recursive compression detected\n", __func__));
227 		return (EINVAL);
228 	}
229 
230 	/* Get crypto descriptors */
231 	crp = crypto_getreq(1);
232 	if (crp == NULL) {
233 		m_freem(m);
234 		DPRINTF(("%s: no crypto descriptors\n", __func__));
235 		IPCOMPSTAT_INC(ipcomps_crypto);
236 		return ENOBUFS;
237 	}
238 	/* Get IPsec-specific opaque pointer */
239 	tc = (struct tdb_crypto *) malloc(sizeof (*tc), M_XDATA, M_NOWAIT|M_ZERO);
240 	if (tc == NULL) {
241 		m_freem(m);
242 		crypto_freereq(crp);
243 		DPRINTF(("%s: cannot allocate tdb_crypto\n", __func__));
244 		IPCOMPSTAT_INC(ipcomps_crypto);
245 		return ENOBUFS;
246 	}
247 	crdc = crp->crp_desc;
248 
249 	crdc->crd_skip = skip + hlen;
250 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
251 	crdc->crd_inject = skip;
252 
253 	tc->tc_ptr = 0;
254 
255 	/* Decompression operation */
256 	crdc->crd_alg = sav->tdb_compalgxform->type;
257 
258 	/* Crypto operation descriptor */
259 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
260 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
261 	crp->crp_buf = (caddr_t) m;
262 	crp->crp_callback = ipcomp_input_cb;
263 	crp->crp_sid = sav->tdb_cryptoid;
264 	crp->crp_opaque = (caddr_t) tc;
265 
266 	/* These are passed as-is to the callback */
267 	tc->tc_spi = sav->spi;
268 	tc->tc_dst = sav->sah->saidx.dst;
269 	tc->tc_proto = sav->sah->saidx.proto;
270 	tc->tc_protoff = protoff;
271 	tc->tc_skip = skip;
272 	KEY_ADDREFSA(sav);
273 	tc->tc_sav = sav;
274 
275 	return crypto_dispatch(crp);
276 }
277 
278 /*
279  * IPComp input callback from the crypto driver.
280  */
281 static int
282 ipcomp_input_cb(struct cryptop *crp)
283 {
284 	char buf[INET6_ADDRSTRLEN];
285 	struct cryptodesc *crd;
286 	struct tdb_crypto *tc;
287 	int skip, protoff;
288 	struct mbuf *m;
289 	struct secasvar *sav;
290 	struct secasindex *saidx;
291 	int hlen = IPCOMP_HLENGTH, error, clen;
292 	u_int8_t nproto;
293 	caddr_t addr;
294 
295 	crd = crp->crp_desc;
296 
297 	tc = (struct tdb_crypto *) crp->crp_opaque;
298 	IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
299 	skip = tc->tc_skip;
300 	protoff = tc->tc_protoff;
301 	m = (struct mbuf *) crp->crp_buf;
302 
303 	sav = tc->tc_sav;
304 	IPSEC_ASSERT(sav != NULL, ("null SA!"));
305 
306 	saidx = &sav->sah->saidx;
307 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
308 		saidx->dst.sa.sa_family == AF_INET6,
309 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
310 
311 	/* Check for crypto errors */
312 	if (crp->crp_etype) {
313 		/* Reset the session ID */
314 		if (sav->tdb_cryptoid != 0)
315 			sav->tdb_cryptoid = crp->crp_sid;
316 
317 		if (crp->crp_etype == EAGAIN) {
318 			return crypto_dispatch(crp);
319 		}
320 		IPCOMPSTAT_INC(ipcomps_noxform);
321 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
322 		error = crp->crp_etype;
323 		goto bad;
324 	}
325 	/* Shouldn't happen... */
326 	if (m == NULL) {
327 		IPCOMPSTAT_INC(ipcomps_crypto);
328 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
329 		error = EINVAL;
330 		goto bad;
331 	}
332 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
333 
334 	clen = crp->crp_olen;		/* Length of data after processing */
335 
336 	/* Release the crypto descriptors */
337 	free(tc, M_XDATA), tc = NULL;
338 	crypto_freereq(crp), crp = NULL;
339 
340 	/* In case it's not done already, adjust the size of the mbuf chain */
341 	m->m_pkthdr.len = clen + hlen + skip;
342 
343 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
344 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
345 		DPRINTF(("%s: m_pullup failed\n", __func__));
346 		error = EINVAL;				/*XXX*/
347 		goto bad;
348 	}
349 
350 	/* Keep the next protocol field */
351 	addr = (caddr_t) mtod(m, struct ip *) + skip;
352 	nproto = ((struct ipcomp *) addr)->comp_nxt;
353 
354 	/* Remove the IPCOMP header */
355 	error = m_striphdr(m, skip, hlen);
356 	if (error) {
357 		IPCOMPSTAT_INC(ipcomps_hdrops);
358 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
359 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
360 		    (u_long) ntohl(sav->spi)));
361 		goto bad;
362 	}
363 
364 	/* Restore the Next Protocol field */
365 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
366 
367 	switch (saidx->dst.sa.sa_family) {
368 #ifdef INET6
369 	case AF_INET6:
370 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
371 		break;
372 #endif
373 #ifdef INET
374 	case AF_INET:
375 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
376 		break;
377 #endif
378 	default:
379 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
380 		    saidx->dst.sa.sa_family, saidx);
381 	}
382 
383 	KEY_FREESAV(&sav);
384 	return error;
385 bad:
386 	if (sav)
387 		KEY_FREESAV(&sav);
388 	if (m)
389 		m_freem(m);
390 	if (tc != NULL)
391 		free(tc, M_XDATA);
392 	if (crp)
393 		crypto_freereq(crp);
394 	return error;
395 }
396 
397 /*
398  * IPComp output routine, called by ipsec[46]_process_packet()
399  */
400 static int
401 ipcomp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
402     int skip, int protoff)
403 {
404 	char buf[INET6_ADDRSTRLEN];
405 	struct secasvar *sav;
406 	struct comp_algo *ipcompx;
407 	int error, ralen, maxpacketsize;
408 	struct cryptodesc *crdc;
409 	struct cryptop *crp;
410 	struct tdb_crypto *tc;
411 
412 	sav = isr->sav;
413 	IPSEC_ASSERT(sav != NULL, ("null SA"));
414 	ipcompx = sav->tdb_compalgxform;
415 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
416 
417 	/*
418 	 * Do not touch the packet in case our payload to compress
419 	 * is lower than the minimal threshold of the compression
420 	 * alogrithm.  We will just send out the data uncompressed.
421 	 * See RFC 3173, 2.2. Non-Expansion Policy.
422 	 */
423 	if (m->m_pkthdr.len <= ipcompx->minlen) {
424 		IPCOMPSTAT_INC(ipcomps_threshold);
425 		return ipsec_process_done(m, isr);
426 	}
427 
428 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
429 	IPCOMPSTAT_INC(ipcomps_output);
430 
431 	/* Check for maximum packet size violations. */
432 	switch (sav->sah->saidx.dst.sa.sa_family) {
433 #ifdef INET
434 	case AF_INET:
435 		maxpacketsize = IP_MAXPACKET;
436 		break;
437 #endif /* INET */
438 #ifdef INET6
439 	case AF_INET6:
440 		maxpacketsize = IPV6_MAXPACKET;
441 		break;
442 #endif /* INET6 */
443 	default:
444 		IPCOMPSTAT_INC(ipcomps_nopf);
445 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
446 		    "IPCA %s/%08lx\n", __func__,
447 		    sav->sah->saidx.dst.sa.sa_family,
448 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
449 		    (u_long) ntohl(sav->spi)));
450 		error = EPFNOSUPPORT;
451 		goto bad;
452 	}
453 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
454 		IPCOMPSTAT_INC(ipcomps_toobig);
455 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
456 		    "(len %u, max len %u)\n", __func__,
457 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
458 		    (u_long) ntohl(sav->spi),
459 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
460 		error = EMSGSIZE;
461 		goto bad;
462 	}
463 
464 	/* Update the counters */
465 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
466 
467 	m = m_unshare(m, M_NOWAIT);
468 	if (m == NULL) {
469 		IPCOMPSTAT_INC(ipcomps_hdrops);
470 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
471 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
472 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
473 		error = ENOBUFS;
474 		goto bad;
475 	}
476 
477 	/* Ok now, we can pass to the crypto processing. */
478 
479 	/* Get crypto descriptors */
480 	crp = crypto_getreq(1);
481 	if (crp == NULL) {
482 		IPCOMPSTAT_INC(ipcomps_crypto);
483 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
484 		error = ENOBUFS;
485 		goto bad;
486 	}
487 	crdc = crp->crp_desc;
488 
489 	/* Compression descriptor */
490 	crdc->crd_skip = skip;
491 	crdc->crd_len = ralen;
492 	crdc->crd_flags = CRD_F_COMP;
493 	crdc->crd_inject = skip;
494 
495 	/* Compression operation */
496 	crdc->crd_alg = ipcompx->type;
497 
498 	/* IPsec-specific opaque crypto info */
499 	tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
500 		M_XDATA, M_NOWAIT|M_ZERO);
501 	if (tc == NULL) {
502 		IPCOMPSTAT_INC(ipcomps_crypto);
503 		DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
504 		crypto_freereq(crp);
505 		error = ENOBUFS;
506 		goto bad;
507 	}
508 
509 	key_addref(isr->sp);
510 	tc->tc_isr = isr;
511 	KEY_ADDREFSA(sav);
512 	tc->tc_sav = sav;
513 	tc->tc_spi = sav->spi;
514 	tc->tc_dst = sav->sah->saidx.dst;
515 	tc->tc_proto = sav->sah->saidx.proto;
516 	tc->tc_protoff = protoff;
517 	tc->tc_skip = skip;
518 
519 	/* Crypto operation descriptor */
520 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
521 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
522 	crp->crp_buf = (caddr_t) m;
523 	crp->crp_callback = ipcomp_output_cb;
524 	crp->crp_opaque = (caddr_t) tc;
525 	crp->crp_sid = sav->tdb_cryptoid;
526 
527 	return crypto_dispatch(crp);
528 bad:
529 	if (m)
530 		m_freem(m);
531 	return (error);
532 }
533 
534 /*
535  * IPComp output callback from the crypto driver.
536  */
537 static int
538 ipcomp_output_cb(struct cryptop *crp)
539 {
540 	char buf[INET6_ADDRSTRLEN];
541 	struct tdb_crypto *tc;
542 	struct ipsecrequest *isr;
543 	struct secasvar *sav;
544 	struct mbuf *m;
545 	int error, skip;
546 
547 	tc = (struct tdb_crypto *) crp->crp_opaque;
548 	IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
549 	m = (struct mbuf *) crp->crp_buf;
550 	skip = tc->tc_skip;
551 
552 	isr = tc->tc_isr;
553 	IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
554 	IPSECREQUEST_LOCK(isr);
555 	sav = tc->tc_sav;
556 	/* With the isr lock released SA pointer can be updated. */
557 	if (sav != isr->sav) {
558 		IPCOMPSTAT_INC(ipcomps_notdb);
559 		DPRINTF(("%s: SA expired while in crypto\n", __func__));
560 		error = ENOBUFS;		/*XXX*/
561 		goto bad;
562 	}
563 
564 	/* Check for crypto errors */
565 	if (crp->crp_etype) {
566 		/* Reset the session ID */
567 		if (sav->tdb_cryptoid != 0)
568 			sav->tdb_cryptoid = crp->crp_sid;
569 
570 		if (crp->crp_etype == EAGAIN) {
571 			IPSECREQUEST_UNLOCK(isr);
572 			return crypto_dispatch(crp);
573 		}
574 		IPCOMPSTAT_INC(ipcomps_noxform);
575 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
576 		error = crp->crp_etype;
577 		goto bad;
578 	}
579 	/* Shouldn't happen... */
580 	if (m == NULL) {
581 		IPCOMPSTAT_INC(ipcomps_crypto);
582 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
583 		error = EINVAL;
584 		goto bad;
585 	}
586 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
587 
588 	if (crp->crp_ilen - skip > crp->crp_olen) {
589 		struct mbuf *mo;
590 		struct ipcomp *ipcomp;
591 		int roff;
592 		uint8_t prot;
593 
594 		/* Compression helped, inject IPCOMP header. */
595 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
596 		if (mo == NULL) {
597 			IPCOMPSTAT_INC(ipcomps_wrap);
598 			DPRINTF(("%s: IPCOMP header inject failed for IPCA %s/%08lx\n",
599 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
600 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
601 			error = ENOBUFS;
602 			goto bad;
603 		}
604 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
605 
606 		/* Initialize the IPCOMP header */
607 		/* XXX alignment always correct? */
608 		switch (sav->sah->saidx.dst.sa.sa_family) {
609 #ifdef INET
610 		case AF_INET:
611 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
612 			break;
613 #endif /* INET */
614 #ifdef INET6
615 		case AF_INET6:
616 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
617 			break;
618 #endif
619 		}
620 		ipcomp->comp_flags = 0;
621 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
622 
623 		/* Fix Next Protocol in IPv4/IPv6 header */
624 		prot = IPPROTO_IPCOMP;
625 		m_copyback(m, tc->tc_protoff, sizeof(u_int8_t),
626 		    (u_char *)&prot);
627 
628 		/* Adjust the length in the IP header */
629 		switch (sav->sah->saidx.dst.sa.sa_family) {
630 #ifdef INET
631 		case AF_INET:
632 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
633 			break;
634 #endif /* INET */
635 #ifdef INET6
636 		case AF_INET6:
637 			mtod(m, struct ip6_hdr *)->ip6_plen =
638 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
639 			break;
640 #endif /* INET6 */
641 		default:
642 			IPCOMPSTAT_INC(ipcomps_nopf);
643 			DPRINTF(("%s: unknown/unsupported protocol "
644 			    "family %d, IPCA %s/%08lx\n", __func__,
645 			    sav->sah->saidx.dst.sa.sa_family,
646 			    ipsec_address(&sav->sah->saidx.dst, buf,
647 				sizeof(buf)), (u_long) ntohl(sav->spi)));
648 			error = EPFNOSUPPORT;
649 			goto bad;
650 		}
651 	} else {
652 		/* Compression was useless, we have lost time. */
653 		IPCOMPSTAT_INC(ipcomps_uncompr);
654 		DPRINTF(("%s: compressions was useless %d - %d <= %d\n",
655 		    __func__, crp->crp_ilen, skip, crp->crp_olen));
656 		/* XXX remember state to not compress the next couple
657 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
658 	}
659 
660 	/* Release the crypto descriptor */
661 	free(tc, M_XDATA);
662 	crypto_freereq(crp);
663 
664 	/* NB: m is reclaimed by ipsec_process_done. */
665 	error = ipsec_process_done(m, isr);
666 	KEY_FREESAV(&sav);
667 	IPSECREQUEST_UNLOCK(isr);
668 	KEY_FREESP(&isr->sp);
669 	return (error);
670 bad:
671 	if (sav)
672 		KEY_FREESAV(&sav);
673 	IPSECREQUEST_UNLOCK(isr);
674 	KEY_FREESP(&isr->sp);
675 	if (m)
676 		m_freem(m);
677 	free(tc, M_XDATA);
678 	crypto_freereq(crp);
679 	return (error);
680 }
681 
682 static struct xformsw ipcomp_xformsw = {
683 	XF_IPCOMP,		XFT_COMP,		"IPcomp",
684 	ipcomp_init,		ipcomp_zeroize,		ipcomp_input,
685 	ipcomp_output
686 };
687 
688 #ifdef INET
689 static const struct encaptab *ipe4_cookie = NULL;
690 extern struct domain inetdomain;
691 static struct protosw ipcomp4_protosw = {
692 	.pr_type =	SOCK_RAW,
693 	.pr_domain =	&inetdomain,
694 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
695 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
696 	.pr_input =	ipcomp_nonexp_input,
697 	.pr_output =	rip_output,
698 	.pr_ctloutput =	rip_ctloutput,
699 	.pr_usrreqs =	&rip_usrreqs
700 };
701 
702 static int
703 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
704     void *arg __unused)
705 {
706 	union sockaddr_union src, dst;
707 	const struct ip *ip;
708 
709 	if (V_ipcomp_enable == 0)
710 		return (0);
711 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
712 		return (0);
713 	bzero(&src, sizeof(src));
714 	bzero(&dst, sizeof(dst));
715 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
716 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
717 	ip = mtod(m, const struct ip *);
718 	src.sin.sin_addr = ip->ip_src;
719 	dst.sin.sin_addr = ip->ip_dst;
720 	return (ipcomp_encapcheck(&src, &dst));
721 }
722 #endif
723 #ifdef INET6
724 static const struct encaptab *ipe6_cookie = NULL;
725 extern struct domain inet6domain;
726 static struct protosw ipcomp6_protosw = {
727 	.pr_type =	SOCK_RAW,
728 	.pr_domain =	&inet6domain,
729 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
730 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
731 	.pr_input =	ipcomp_nonexp_input,
732 	.pr_output =	rip6_output,
733 	.pr_ctloutput =	rip6_ctloutput,
734 	.pr_usrreqs =	&rip6_usrreqs
735 };
736 
737 static int
738 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
739     void *arg __unused)
740 {
741 	union sockaddr_union src, dst;
742 	const struct ip6_hdr *ip6;
743 
744 	if (V_ipcomp_enable == 0)
745 		return (0);
746 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
747 		return (0);
748 	bzero(&src, sizeof(src));
749 	bzero(&dst, sizeof(dst));
750 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
751 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
752 	ip6 = mtod(m, const struct ip6_hdr *);
753 	src.sin6.sin6_addr = ip6->ip6_src;
754 	dst.sin6.sin6_addr = ip6->ip6_dst;
755 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
756 		/* XXX: sa6_recoverscope() */
757 		src.sin6.sin6_scope_id =
758 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
759 		src.sin6.sin6_addr.s6_addr16[1] = 0;
760 	}
761 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
762 		/* XXX: sa6_recoverscope() */
763 		dst.sin6.sin6_scope_id =
764 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
765 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
766 	}
767 	return (ipcomp_encapcheck(&src, &dst));
768 }
769 #endif
770 
771 static void
772 ipcomp_attach(void)
773 {
774 
775 #ifdef INET
776 	ipe4_cookie = encap_attach_func(AF_INET, -1,
777 	    ipcomp4_nonexp_encapcheck, &ipcomp4_protosw, NULL);
778 #endif
779 #ifdef INET6
780 	ipe6_cookie = encap_attach_func(AF_INET6, -1,
781 	    ipcomp6_nonexp_encapcheck, &ipcomp6_protosw, NULL);
782 #endif
783 	xform_register(&ipcomp_xformsw);
784 }
785 
786 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
787     ipcomp_attach, NULL);
788