xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision 396c556d77189a5c474d35cec6f44a762e310b7d)
1 /*	$FreeBSD$	*/
2 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
3 
4 /*-
5  * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *   notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *   notice, this list of conditions and the following disclaimer in the
15  *   documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *   derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 /* IP payload compression protocol (IPComp), see RFC 2393 */
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/mbuf.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/socket.h>
41 #include <sys/kernel.h>
42 #include <sys/protosw.h>
43 #include <sys/sysctl.h>
44 
45 #include <netinet/in.h>
46 #include <netinet/in_systm.h>
47 #include <netinet/ip.h>
48 #include <netinet/ip_var.h>
49 #include <netinet/ip_encap.h>
50 
51 #include <net/netisr.h>
52 #include <net/vnet.h>
53 
54 #include <netipsec/ipsec.h>
55 #include <netipsec/xform.h>
56 
57 #ifdef INET6
58 #include <netinet/ip6.h>
59 #include <netinet6/ip6_var.h>
60 #include <netipsec/ipsec6.h>
61 #endif
62 
63 #include <netipsec/ipcomp.h>
64 #include <netipsec/ipcomp_var.h>
65 
66 #include <netipsec/key.h>
67 #include <netipsec/key_debug.h>
68 
69 #include <opencrypto/cryptodev.h>
70 #include <opencrypto/deflate.h>
71 #include <opencrypto/xform.h>
72 
73 VNET_DEFINE(int, ipcomp_enable) = 1;
74 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
75 VNET_PCPUSTAT_SYSINIT(ipcompstat);
76 
77 #ifdef VIMAGE
78 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
79 #endif /* VIMAGE */
80 
81 SYSCTL_DECL(_net_inet_ipcomp);
82 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
83 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
84 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
85     struct ipcompstat, ipcompstat,
86     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
87 
88 static int ipcomp_input_cb(struct cryptop *crp);
89 static int ipcomp_output_cb(struct cryptop *crp);
90 
91 /*
92  * RFC 3173 p 2.2. Non-Expansion Policy:
93  * If the total size of a compressed payload and the IPComp header, as
94  * defined in section 3, is not smaller than the size of the original
95  * payload, the IP datagram MUST be sent in the original non-compressed
96  * form.
97  *
98  * When we use IPComp in tunnel mode, for small packets we will receive
99  * encapsulated IP-IP datagrams without any compression and without IPComp
100  * header.
101  */
102 static int
103 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
104 {
105 	struct secasvar *sav;
106 
107 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
108 	if (sav == NULL)
109 		return (0);
110 	key_freesav(&sav);
111 
112 	if (src->sa.sa_family == AF_INET)
113 		return (sizeof(struct in_addr) << 4);
114 	else
115 		return (sizeof(struct in6_addr) << 4);
116 }
117 
118 static int
119 ipcomp_nonexp_input(struct mbuf **mp, int *offp, int proto)
120 {
121 	int isr;
122 
123 	switch (proto) {
124 #ifdef INET
125 	case IPPROTO_IPV4:
126 		isr = NETISR_IP;
127 		break;
128 #endif
129 #ifdef INET6
130 	case IPPROTO_IPV6:
131 		isr = NETISR_IPV6;
132 		break;
133 #endif
134 	default:
135 		IPCOMPSTAT_INC(ipcomps_nopf);
136 		m_freem(*mp);
137 		return (IPPROTO_DONE);
138 	}
139 	m_adj(*mp, *offp);
140 	IPCOMPSTAT_ADD(ipcomps_ibytes, (*mp)->m_pkthdr.len);
141 	IPCOMPSTAT_INC(ipcomps_input);
142 	netisr_dispatch(isr, *mp);
143 	return (IPPROTO_DONE);
144 }
145 
146 /*
147  * ipcomp_init() is called when an CPI is being set up.
148  */
149 static int
150 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
151 {
152 	const struct comp_algo *tcomp;
153 	struct cryptoini cric;
154 
155 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
156 	tcomp = comp_algorithm_lookup(sav->alg_enc);
157 	if (tcomp == NULL) {
158 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
159 			 sav->alg_comp));
160 		return EINVAL;
161 	}
162 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
163 	sav->tdb_xform = xsp;
164 	sav->tdb_compalgxform = tcomp;
165 
166 	/* Initialize crypto session */
167 	bzero(&cric, sizeof (cric));
168 	cric.cri_alg = sav->tdb_compalgxform->type;
169 
170 	return crypto_newsession(&sav->tdb_cryptoid, &cric, V_crypto_support);
171 }
172 
173 /*
174  * ipcomp_zeroize() used when IPCA is deleted
175  */
176 static int
177 ipcomp_zeroize(struct secasvar *sav)
178 {
179 	int err;
180 
181 	err = crypto_freesession(sav->tdb_cryptoid);
182 	sav->tdb_cryptoid = 0;
183 	return err;
184 }
185 
186 /*
187  * ipcomp_input() gets called to uncompress an input packet
188  */
189 static int
190 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
191 {
192 	struct xform_data *xd;
193 	struct cryptodesc *crdc;
194 	struct cryptop *crp;
195 	struct ipcomp *ipcomp;
196 	caddr_t addr;
197 	int error, hlen = IPCOMP_HLENGTH;
198 
199 	/*
200 	 * Check that the next header of the IPComp is not IPComp again, before
201 	 * doing any real work.  Given it is not possible to do double
202 	 * compression it means someone is playing tricks on us.
203 	 */
204 	error = ENOBUFS;
205 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
206 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
207 		DPRINTF(("%s: m_pullup failed\n", __func__));
208 		key_freesav(&sav);
209 		return (error);
210 	}
211 	addr = (caddr_t) mtod(m, struct ip *) + skip;
212 	ipcomp = (struct ipcomp *)addr;
213 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
214 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
215 		DPRINTF(("%s: recursive compression detected\n", __func__));
216 		error = EINVAL;
217 		goto bad;
218 	}
219 
220 	/* Get crypto descriptors */
221 	crp = crypto_getreq(1);
222 	if (crp == NULL) {
223 		DPRINTF(("%s: no crypto descriptors\n", __func__));
224 		IPCOMPSTAT_INC(ipcomps_crypto);
225 		goto bad;
226 	}
227 	/* Get IPsec-specific opaque pointer */
228 	xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
229 	if (xd == NULL) {
230 		DPRINTF(("%s: cannot allocate xform_data\n", __func__));
231 		IPCOMPSTAT_INC(ipcomps_crypto);
232 		crypto_freereq(crp);
233 		goto bad;
234 	}
235 	crdc = crp->crp_desc;
236 
237 	crdc->crd_skip = skip + hlen;
238 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
239 	crdc->crd_inject = skip;
240 
241 	/* Decompression operation */
242 	crdc->crd_alg = sav->tdb_compalgxform->type;
243 
244 
245 	/* Crypto operation descriptor */
246 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
247 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
248 	crp->crp_buf = (caddr_t) m;
249 	crp->crp_callback = ipcomp_input_cb;
250 	crp->crp_opaque = (caddr_t) xd;
251 
252 	/* These are passed as-is to the callback */
253 	xd->sav = sav;
254 	xd->protoff = protoff;
255 	xd->skip = skip;
256 
257 	SECASVAR_LOCK(sav);
258 	crp->crp_sid = xd->cryptoid = sav->tdb_cryptoid;
259 	SECASVAR_UNLOCK(sav);
260 
261 	return crypto_dispatch(crp);
262 bad:
263 	m_freem(m);
264 	key_freesav(&sav);
265 	return (error);
266 }
267 
268 /*
269  * IPComp input callback from the crypto driver.
270  */
271 static int
272 ipcomp_input_cb(struct cryptop *crp)
273 {
274 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
275 	struct cryptodesc *crd;
276 	struct xform_data *xd;
277 	struct mbuf *m;
278 	struct secasvar *sav;
279 	struct secasindex *saidx;
280 	caddr_t addr;
281 	uint64_t cryptoid;
282 	int hlen = IPCOMP_HLENGTH, error, clen;
283 	int skip, protoff;
284 	uint8_t nproto;
285 
286 	crd = crp->crp_desc;
287 
288 	m = (struct mbuf *) crp->crp_buf;
289 	xd = (struct xform_data *) crp->crp_opaque;
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_sid, &cryptoid) != 0)
304 				crypto_freesession(cryptoid);
305 			xd->cryptoid = crp->crp_sid;
306 			return (crypto_dispatch(crp));
307 		}
308 		IPCOMPSTAT_INC(ipcomps_noxform);
309 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
310 		error = crp->crp_etype;
311 		goto bad;
312 	}
313 	/* Shouldn't happen... */
314 	if (m == NULL) {
315 		IPCOMPSTAT_INC(ipcomps_crypto);
316 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
317 		error = EINVAL;
318 		goto bad;
319 	}
320 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
321 
322 	clen = crp->crp_olen;		/* Length of data after processing */
323 
324 	/* Release the crypto descriptors */
325 	free(xd, M_XDATA), xd = NULL;
326 	crypto_freereq(crp), crp = NULL;
327 
328 	/* In case it's not done already, adjust the size of the mbuf chain */
329 	m->m_pkthdr.len = clen + hlen + skip;
330 
331 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
332 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
333 		DPRINTF(("%s: m_pullup failed\n", __func__));
334 		error = EINVAL;				/*XXX*/
335 		goto bad;
336 	}
337 
338 	/* Keep the next protocol field */
339 	addr = (caddr_t) mtod(m, struct ip *) + skip;
340 	nproto = ((struct ipcomp *) addr)->comp_nxt;
341 
342 	/* Remove the IPCOMP header */
343 	error = m_striphdr(m, skip, hlen);
344 	if (error) {
345 		IPCOMPSTAT_INC(ipcomps_hdrops);
346 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
347 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
348 		    (u_long) ntohl(sav->spi)));
349 		goto bad;
350 	}
351 
352 	/* Restore the Next Protocol field */
353 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
354 
355 	switch (saidx->dst.sa.sa_family) {
356 #ifdef INET6
357 	case AF_INET6:
358 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
359 		break;
360 #endif
361 #ifdef INET
362 	case AF_INET:
363 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
364 		break;
365 #endif
366 	default:
367 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
368 		    saidx->dst.sa.sa_family, saidx);
369 	}
370 	return error;
371 bad:
372 	if (sav != NULL)
373 		key_freesav(&sav);
374 	if (m != NULL)
375 		m_freem(m);
376 	if (xd != NULL)
377 		free(xd, M_XDATA);
378 	if (crp != NULL)
379 		crypto_freereq(crp);
380 	return error;
381 }
382 
383 /*
384  * IPComp output routine, called by ipsec[46]_perform_request()
385  */
386 static int
387 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
388     u_int idx, int skip, int protoff)
389 {
390 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
391 	const struct comp_algo *ipcompx;
392 	struct cryptodesc *crdc;
393 	struct cryptop *crp;
394 	struct xform_data *xd;
395 	int error, ralen, maxpacketsize;
396 
397 	IPSEC_ASSERT(sav != NULL, ("null SA"));
398 	ipcompx = sav->tdb_compalgxform;
399 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
400 
401 	/*
402 	 * Do not touch the packet in case our payload to compress
403 	 * is lower than the minimal threshold of the compression
404 	 * alogrithm.  We will just send out the data uncompressed.
405 	 * See RFC 3173, 2.2. Non-Expansion Policy.
406 	 */
407 	if (m->m_pkthdr.len <= ipcompx->minlen) {
408 		IPCOMPSTAT_INC(ipcomps_threshold);
409 		return ipsec_process_done(m, sp, sav, idx);
410 	}
411 
412 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
413 	IPCOMPSTAT_INC(ipcomps_output);
414 
415 	/* Check for maximum packet size violations. */
416 	switch (sav->sah->saidx.dst.sa.sa_family) {
417 #ifdef INET
418 	case AF_INET:
419 		maxpacketsize = IP_MAXPACKET;
420 		break;
421 #endif /* INET */
422 #ifdef INET6
423 	case AF_INET6:
424 		maxpacketsize = IPV6_MAXPACKET;
425 		break;
426 #endif /* INET6 */
427 	default:
428 		IPCOMPSTAT_INC(ipcomps_nopf);
429 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
430 		    "IPCA %s/%08lx\n", __func__,
431 		    sav->sah->saidx.dst.sa.sa_family,
432 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
433 		    (u_long) ntohl(sav->spi)));
434 		error = EPFNOSUPPORT;
435 		goto bad;
436 	}
437 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
438 		IPCOMPSTAT_INC(ipcomps_toobig);
439 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
440 		    "(len %u, max len %u)\n", __func__,
441 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
442 		    (u_long) ntohl(sav->spi),
443 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
444 		error = EMSGSIZE;
445 		goto bad;
446 	}
447 
448 	/* Update the counters */
449 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
450 
451 	m = m_unshare(m, M_NOWAIT);
452 	if (m == NULL) {
453 		IPCOMPSTAT_INC(ipcomps_hdrops);
454 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
455 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
456 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
457 		error = ENOBUFS;
458 		goto bad;
459 	}
460 
461 	/* Ok now, we can pass to the crypto processing. */
462 
463 	/* Get crypto descriptors */
464 	crp = crypto_getreq(1);
465 	if (crp == NULL) {
466 		IPCOMPSTAT_INC(ipcomps_crypto);
467 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
468 		error = ENOBUFS;
469 		goto bad;
470 	}
471 	crdc = crp->crp_desc;
472 
473 	/* Compression descriptor */
474 	crdc->crd_skip = skip;
475 	crdc->crd_len = ralen;
476 	crdc->crd_flags = CRD_F_COMP;
477 	crdc->crd_inject = skip;
478 
479 	/* Compression operation */
480 	crdc->crd_alg = ipcompx->type;
481 
482 	/* IPsec-specific opaque crypto info */
483 	xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
484 	if (xd == NULL) {
485 		IPCOMPSTAT_INC(ipcomps_crypto);
486 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
487 		crypto_freereq(crp);
488 		error = ENOBUFS;
489 		goto bad;
490 	}
491 
492 	xd->sp = sp;
493 	xd->sav = sav;
494 	xd->idx = idx;
495 	xd->skip = skip;
496 	xd->protoff = protoff;
497 
498 	/* Crypto operation descriptor */
499 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
500 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
501 	crp->crp_buf = (caddr_t) m;
502 	crp->crp_callback = ipcomp_output_cb;
503 	crp->crp_opaque = (caddr_t) xd;
504 
505 	SECASVAR_LOCK(sav);
506 	crp->crp_sid = xd->cryptoid = sav->tdb_cryptoid;
507 	SECASVAR_UNLOCK(sav);
508 
509 	return crypto_dispatch(crp);
510 bad:
511 	if (m)
512 		m_freem(m);
513 	key_freesav(&sav);
514 	key_freesp(&sp);
515 	return (error);
516 }
517 
518 /*
519  * IPComp output callback from the crypto driver.
520  */
521 static int
522 ipcomp_output_cb(struct cryptop *crp)
523 {
524 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
525 	struct xform_data *xd;
526 	struct secpolicy *sp;
527 	struct secasvar *sav;
528 	struct mbuf *m;
529 	uint64_t cryptoid;
530 	u_int idx;
531 	int error, skip, protoff;
532 
533 	m = (struct mbuf *) crp->crp_buf;
534 	xd = (struct xform_data *) crp->crp_opaque;
535 	idx = xd->idx;
536 	sp = xd->sp;
537 	sav = xd->sav;
538 	skip = xd->skip;
539 	protoff = xd->protoff;
540 	cryptoid = xd->cryptoid;
541 
542 	/* Check for crypto errors */
543 	if (crp->crp_etype) {
544 		if (crp->crp_etype == EAGAIN) {
545 			/* Reset the session ID */
546 			if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
547 				crypto_freesession(cryptoid);
548 			xd->cryptoid = crp->crp_sid;
549 			return (crypto_dispatch(crp));
550 		}
551 		IPCOMPSTAT_INC(ipcomps_noxform);
552 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
553 		error = crp->crp_etype;
554 		goto bad;
555 	}
556 	/* Shouldn't happen... */
557 	if (m == NULL) {
558 		IPCOMPSTAT_INC(ipcomps_crypto);
559 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
560 		error = EINVAL;
561 		goto bad;
562 	}
563 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
564 
565 	if (crp->crp_ilen - skip > crp->crp_olen) {
566 		struct mbuf *mo;
567 		struct ipcomp *ipcomp;
568 		int roff;
569 		uint8_t prot;
570 
571 		/* Compression helped, inject IPCOMP header. */
572 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
573 		if (mo == NULL) {
574 			IPCOMPSTAT_INC(ipcomps_wrap);
575 			DPRINTF(("%s: IPCOMP header inject failed "
576 			    "for IPCA %s/%08lx\n",
577 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
578 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
579 			error = ENOBUFS;
580 			goto bad;
581 		}
582 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
583 
584 		/* Initialize the IPCOMP header */
585 		/* XXX alignment always correct? */
586 		switch (sav->sah->saidx.dst.sa.sa_family) {
587 #ifdef INET
588 		case AF_INET:
589 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
590 			break;
591 #endif /* INET */
592 #ifdef INET6
593 		case AF_INET6:
594 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
595 			break;
596 #endif
597 		}
598 		ipcomp->comp_flags = 0;
599 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
600 
601 		/* Fix Next Protocol in IPv4/IPv6 header */
602 		prot = IPPROTO_IPCOMP;
603 		m_copyback(m, protoff, sizeof(u_int8_t),
604 		    (u_char *)&prot);
605 
606 		/* Adjust the length in the IP header */
607 		switch (sav->sah->saidx.dst.sa.sa_family) {
608 #ifdef INET
609 		case AF_INET:
610 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
611 			break;
612 #endif /* INET */
613 #ifdef INET6
614 		case AF_INET6:
615 			mtod(m, struct ip6_hdr *)->ip6_plen =
616 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
617 			break;
618 #endif /* INET6 */
619 		default:
620 			IPCOMPSTAT_INC(ipcomps_nopf);
621 			DPRINTF(("%s: unknown/unsupported protocol "
622 			    "family %d, IPCA %s/%08lx\n", __func__,
623 			    sav->sah->saidx.dst.sa.sa_family,
624 			    ipsec_address(&sav->sah->saidx.dst, buf,
625 				sizeof(buf)), (u_long) ntohl(sav->spi)));
626 			error = EPFNOSUPPORT;
627 			goto bad;
628 		}
629 	} else {
630 		/* Compression was useless, we have lost time. */
631 		IPCOMPSTAT_INC(ipcomps_uncompr);
632 		DPRINTF(("%s: compressions was useless %d - %d <= %d\n",
633 		    __func__, crp->crp_ilen, skip, crp->crp_olen));
634 		/* XXX remember state to not compress the next couple
635 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
636 	}
637 
638 	/* Release the crypto descriptor */
639 	free(xd, M_XDATA);
640 	crypto_freereq(crp);
641 
642 	/* NB: m is reclaimed by ipsec_process_done. */
643 	error = ipsec_process_done(m, sp, sav, idx);
644 	return (error);
645 bad:
646 	if (m)
647 		m_freem(m);
648 	free(xd, M_XDATA);
649 	crypto_freereq(crp);
650 	key_freesav(&sav);
651 	key_freesp(&sp);
652 	return (error);
653 }
654 
655 #ifdef INET
656 static const struct encaptab *ipe4_cookie = NULL;
657 extern struct domain inetdomain;
658 static struct protosw ipcomp4_protosw = {
659 	.pr_type =	SOCK_RAW,
660 	.pr_domain =	&inetdomain,
661 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
662 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
663 	.pr_input =	ipcomp_nonexp_input,
664 	.pr_output =	rip_output,
665 	.pr_ctloutput =	rip_ctloutput,
666 	.pr_usrreqs =	&rip_usrreqs
667 };
668 
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 #endif
690 #ifdef INET6
691 static const struct encaptab *ipe6_cookie = NULL;
692 extern struct domain inet6domain;
693 static struct protosw ipcomp6_protosw = {
694 	.pr_type =	SOCK_RAW,
695 	.pr_domain =	&inet6domain,
696 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
697 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
698 	.pr_input =	ipcomp_nonexp_input,
699 	.pr_output =	rip6_output,
700 	.pr_ctloutput =	rip6_ctloutput,
701 	.pr_usrreqs =	&rip6_usrreqs
702 };
703 
704 static int
705 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
706     void *arg __unused)
707 {
708 	union sockaddr_union src, dst;
709 	const struct ip6_hdr *ip6;
710 
711 	if (V_ipcomp_enable == 0)
712 		return (0);
713 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
714 		return (0);
715 	bzero(&src, sizeof(src));
716 	bzero(&dst, sizeof(dst));
717 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
718 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
719 	ip6 = mtod(m, const struct ip6_hdr *);
720 	src.sin6.sin6_addr = ip6->ip6_src;
721 	dst.sin6.sin6_addr = ip6->ip6_dst;
722 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
723 		/* XXX: sa6_recoverscope() */
724 		src.sin6.sin6_scope_id =
725 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
726 		src.sin6.sin6_addr.s6_addr16[1] = 0;
727 	}
728 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
729 		/* XXX: sa6_recoverscope() */
730 		dst.sin6.sin6_scope_id =
731 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
732 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
733 	}
734 	return (ipcomp_encapcheck(&src, &dst));
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 = encap_attach_func(AF_INET, -1,
753 	    ipcomp4_nonexp_encapcheck, &ipcomp4_protosw, NULL);
754 #endif
755 #ifdef INET6
756 	ipe6_cookie = encap_attach_func(AF_INET6, -1,
757 	    ipcomp6_nonexp_encapcheck, &ipcomp6_protosw, NULL);
758 #endif
759 	xform_attach(&ipcomp_xformsw);
760 }
761 
762 static void
763 ipcomp_detach(void)
764 {
765 
766 #ifdef INET
767 	encap_detach(ipe4_cookie);
768 #endif
769 #ifdef INET6
770 	encap_detach(ipe6_cookie);
771 #endif
772 	xform_detach(&ipcomp_xformsw);
773 }
774 
775 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
776     ipcomp_attach, NULL);
777 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
778     ipcomp_detach, NULL);
779