xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision e796cc77c586c2955b2f3940dbf4991b31e8d289)
1 /*	$FreeBSD$	*/
2 /* $OpenBSD: ip_ipcomp.c,v 1.1 2001/07/05 12:08:52 jjbg Exp $ */
3 
4 /*-
5  * SPDX-License-Identifier: BSD-3-Clause
6  *
7  * Copyright (c) 2001 Jean-Jacques Bernard-Gundol (jj@wabbitt.org)
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *   notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *   notice, this list of conditions and the following disclaimer in the
17  *   documentation and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote products
19  *   derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /* IP payload compression protocol (IPComp), see RFC 2393 */
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/mbuf.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/socket.h>
43 #include <sys/kernel.h>
44 #include <sys/protosw.h>
45 #include <sys/sysctl.h>
46 
47 #include <netinet/in.h>
48 #include <netinet/in_systm.h>
49 #include <netinet/ip.h>
50 #include <netinet/ip_var.h>
51 #include <netinet/ip_encap.h>
52 
53 #include <net/netisr.h>
54 #include <net/vnet.h>
55 
56 #include <netipsec/ipsec.h>
57 #include <netipsec/xform.h>
58 
59 #ifdef INET6
60 #include <netinet/ip6.h>
61 #include <netinet6/ip6_var.h>
62 #include <netipsec/ipsec6.h>
63 #endif
64 
65 #include <netipsec/ipcomp.h>
66 #include <netipsec/ipcomp_var.h>
67 
68 #include <netipsec/key.h>
69 #include <netipsec/key_debug.h>
70 
71 #include <opencrypto/cryptodev.h>
72 #include <opencrypto/deflate.h>
73 #include <opencrypto/xform.h>
74 
75 VNET_DEFINE(int, ipcomp_enable) = 1;
76 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
77 VNET_PCPUSTAT_SYSINIT(ipcompstat);
78 
79 #ifdef VIMAGE
80 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
81 #endif /* VIMAGE */
82 
83 SYSCTL_DECL(_net_inet_ipcomp);
84 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
85 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
86 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
87     struct ipcompstat, ipcompstat,
88     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
89 
90 static int ipcomp_input_cb(struct cryptop *crp);
91 static int ipcomp_output_cb(struct cryptop *crp);
92 
93 /*
94  * RFC 3173 p 2.2. Non-Expansion Policy:
95  * If the total size of a compressed payload and the IPComp header, as
96  * defined in section 3, is not smaller than the size of the original
97  * payload, the IP datagram MUST be sent in the original non-compressed
98  * form.
99  *
100  * When we use IPComp in tunnel mode, for small packets we will receive
101  * encapsulated IP-IP datagrams without any compression and without IPComp
102  * header.
103  */
104 static int
105 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
106 {
107 	struct secasvar *sav;
108 
109 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
110 	if (sav == NULL)
111 		return (0);
112 	key_freesav(&sav);
113 
114 	if (src->sa.sa_family == AF_INET)
115 		return (sizeof(struct in_addr) << 4);
116 	else
117 		return (sizeof(struct in6_addr) << 4);
118 }
119 
120 static int
121 ipcomp_nonexp_input(struct mbuf **mp, int *offp, int proto)
122 {
123 	int isr;
124 
125 	switch (proto) {
126 #ifdef INET
127 	case IPPROTO_IPV4:
128 		isr = NETISR_IP;
129 		break;
130 #endif
131 #ifdef INET6
132 	case IPPROTO_IPV6:
133 		isr = NETISR_IPV6;
134 		break;
135 #endif
136 	default:
137 		IPCOMPSTAT_INC(ipcomps_nopf);
138 		m_freem(*mp);
139 		return (IPPROTO_DONE);
140 	}
141 	m_adj(*mp, *offp);
142 	IPCOMPSTAT_ADD(ipcomps_ibytes, (*mp)->m_pkthdr.len);
143 	IPCOMPSTAT_INC(ipcomps_input);
144 	netisr_dispatch(isr, *mp);
145 	return (IPPROTO_DONE);
146 }
147 
148 /*
149  * ipcomp_init() is called when an CPI is being set up.
150  */
151 static int
152 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
153 {
154 	const struct comp_algo *tcomp;
155 	struct cryptoini cric;
156 
157 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
158 	tcomp = comp_algorithm_lookup(sav->alg_enc);
159 	if (tcomp == NULL) {
160 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
161 			 sav->alg_comp));
162 		return EINVAL;
163 	}
164 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
165 	sav->tdb_xform = xsp;
166 	sav->tdb_compalgxform = tcomp;
167 
168 	/* Initialize crypto session */
169 	bzero(&cric, sizeof (cric));
170 	cric.cri_alg = sav->tdb_compalgxform->type;
171 
172 	return crypto_newsession(&sav->tdb_cryptoid, &cric, V_crypto_support);
173 }
174 
175 /*
176  * ipcomp_zeroize() used when IPCA is deleted
177  */
178 static int
179 ipcomp_zeroize(struct secasvar *sav)
180 {
181 	int err;
182 
183 	err = crypto_freesession(sav->tdb_cryptoid);
184 	sav->tdb_cryptoid = 0;
185 	return err;
186 }
187 
188 /*
189  * ipcomp_input() gets called to uncompress an input packet
190  */
191 static int
192 ipcomp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
193 {
194 	struct xform_data *xd;
195 	struct cryptodesc *crdc;
196 	struct cryptop *crp;
197 	struct ipcomp *ipcomp;
198 	caddr_t addr;
199 	int error, hlen = IPCOMP_HLENGTH;
200 
201 	/*
202 	 * Check that the next header of the IPComp is not IPComp again, before
203 	 * doing any real work.  Given it is not possible to do double
204 	 * compression it means someone is playing tricks on us.
205 	 */
206 	error = ENOBUFS;
207 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
208 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
209 		DPRINTF(("%s: m_pullup failed\n", __func__));
210 		key_freesav(&sav);
211 		return (error);
212 	}
213 	addr = (caddr_t) mtod(m, struct ip *) + skip;
214 	ipcomp = (struct ipcomp *)addr;
215 	if (ipcomp->comp_nxt == IPPROTO_IPCOMP) {
216 		IPCOMPSTAT_INC(ipcomps_pdrops);	/* XXX have our own stats? */
217 		DPRINTF(("%s: recursive compression detected\n", __func__));
218 		error = EINVAL;
219 		goto bad;
220 	}
221 
222 	/* Get crypto descriptors */
223 	crp = crypto_getreq(1);
224 	if (crp == NULL) {
225 		DPRINTF(("%s: no crypto descriptors\n", __func__));
226 		IPCOMPSTAT_INC(ipcomps_crypto);
227 		goto bad;
228 	}
229 	/* Get IPsec-specific opaque pointer */
230 	xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
231 	if (xd == NULL) {
232 		DPRINTF(("%s: cannot allocate xform_data\n", __func__));
233 		IPCOMPSTAT_INC(ipcomps_crypto);
234 		crypto_freereq(crp);
235 		goto bad;
236 	}
237 	crdc = crp->crp_desc;
238 
239 	crdc->crd_skip = skip + hlen;
240 	crdc->crd_len = m->m_pkthdr.len - (skip + hlen);
241 	crdc->crd_inject = skip;
242 
243 	/* Decompression operation */
244 	crdc->crd_alg = sav->tdb_compalgxform->type;
245 
246 
247 	/* Crypto operation descriptor */
248 	crp->crp_ilen = m->m_pkthdr.len - (skip + hlen);
249 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
250 	crp->crp_buf = (caddr_t) m;
251 	crp->crp_callback = ipcomp_input_cb;
252 	crp->crp_opaque = (caddr_t) xd;
253 
254 	/* These are passed as-is to the callback */
255 	xd->sav = sav;
256 	xd->protoff = protoff;
257 	xd->skip = skip;
258 	xd->vnet = curvnet;
259 
260 	SECASVAR_LOCK(sav);
261 	crp->crp_sid = xd->cryptoid = sav->tdb_cryptoid;
262 	SECASVAR_UNLOCK(sav);
263 
264 	return crypto_dispatch(crp);
265 bad:
266 	m_freem(m);
267 	key_freesav(&sav);
268 	return (error);
269 }
270 
271 /*
272  * IPComp input callback from the crypto driver.
273  */
274 static int
275 ipcomp_input_cb(struct cryptop *crp)
276 {
277 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
278 	struct xform_data *xd;
279 	struct mbuf *m;
280 	struct secasvar *sav;
281 	struct secasindex *saidx;
282 	caddr_t addr;
283 	uint64_t cryptoid;
284 	int hlen = IPCOMP_HLENGTH, error, clen;
285 	int skip, protoff;
286 	uint8_t nproto;
287 
288 	m = (struct mbuf *) crp->crp_buf;
289 	xd = (struct xform_data *) crp->crp_opaque;
290 	CURVNET_SET(xd->vnet);
291 	sav = xd->sav;
292 	skip = xd->skip;
293 	protoff = xd->protoff;
294 	cryptoid = xd->cryptoid;
295 	saidx = &sav->sah->saidx;
296 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
297 		saidx->dst.sa.sa_family == AF_INET6,
298 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
299 
300 	/* Check for crypto errors */
301 	if (crp->crp_etype) {
302 		if (crp->crp_etype == EAGAIN) {
303 			/* Reset the session ID */
304 			if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
305 				crypto_freesession(cryptoid);
306 			xd->cryptoid = crp->crp_sid;
307 			CURVNET_RESTORE();
308 			return (crypto_dispatch(crp));
309 		}
310 		IPCOMPSTAT_INC(ipcomps_noxform);
311 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
312 		error = crp->crp_etype;
313 		goto bad;
314 	}
315 	/* Shouldn't happen... */
316 	if (m == NULL) {
317 		IPCOMPSTAT_INC(ipcomps_crypto);
318 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
319 		error = EINVAL;
320 		goto bad;
321 	}
322 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
323 
324 	clen = crp->crp_olen;		/* Length of data after processing */
325 
326 	/* Release the crypto descriptors */
327 	free(xd, M_XDATA), xd = NULL;
328 	crypto_freereq(crp), crp = NULL;
329 
330 	/* In case it's not done already, adjust the size of the mbuf chain */
331 	m->m_pkthdr.len = clen + hlen + skip;
332 
333 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
334 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
335 		DPRINTF(("%s: m_pullup failed\n", __func__));
336 		error = EINVAL;				/*XXX*/
337 		goto bad;
338 	}
339 
340 	/* Keep the next protocol field */
341 	addr = (caddr_t) mtod(m, struct ip *) + skip;
342 	nproto = ((struct ipcomp *) addr)->comp_nxt;
343 
344 	/* Remove the IPCOMP header */
345 	error = m_striphdr(m, skip, hlen);
346 	if (error) {
347 		IPCOMPSTAT_INC(ipcomps_hdrops);
348 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
349 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
350 		    (u_long) ntohl(sav->spi)));
351 		goto bad;
352 	}
353 
354 	/* Restore the Next Protocol field */
355 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
356 
357 	switch (saidx->dst.sa.sa_family) {
358 #ifdef INET6
359 	case AF_INET6:
360 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
361 		break;
362 #endif
363 #ifdef INET
364 	case AF_INET:
365 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
366 		break;
367 #endif
368 	default:
369 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
370 		    saidx->dst.sa.sa_family, saidx);
371 	}
372 	CURVNET_RESTORE();
373 	return error;
374 bad:
375 	CURVNET_RESTORE();
376 	if (sav != NULL)
377 		key_freesav(&sav);
378 	if (m != NULL)
379 		m_freem(m);
380 	if (xd != NULL)
381 		free(xd, M_XDATA);
382 	if (crp != NULL)
383 		crypto_freereq(crp);
384 	return error;
385 }
386 
387 /*
388  * IPComp output routine, called by ipsec[46]_perform_request()
389  */
390 static int
391 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
392     u_int idx, int skip, int protoff)
393 {
394 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
395 	const struct comp_algo *ipcompx;
396 	struct cryptodesc *crdc;
397 	struct cryptop *crp;
398 	struct xform_data *xd;
399 	int error, ralen, maxpacketsize;
400 
401 	IPSEC_ASSERT(sav != NULL, ("null SA"));
402 	ipcompx = sav->tdb_compalgxform;
403 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
404 
405 	/*
406 	 * Do not touch the packet in case our payload to compress
407 	 * is lower than the minimal threshold of the compression
408 	 * alogrithm.  We will just send out the data uncompressed.
409 	 * See RFC 3173, 2.2. Non-Expansion Policy.
410 	 */
411 	if (m->m_pkthdr.len <= ipcompx->minlen) {
412 		IPCOMPSTAT_INC(ipcomps_threshold);
413 		return ipsec_process_done(m, sp, sav, idx);
414 	}
415 
416 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
417 	IPCOMPSTAT_INC(ipcomps_output);
418 
419 	/* Check for maximum packet size violations. */
420 	switch (sav->sah->saidx.dst.sa.sa_family) {
421 #ifdef INET
422 	case AF_INET:
423 		maxpacketsize = IP_MAXPACKET;
424 		break;
425 #endif /* INET */
426 #ifdef INET6
427 	case AF_INET6:
428 		maxpacketsize = IPV6_MAXPACKET;
429 		break;
430 #endif /* INET6 */
431 	default:
432 		IPCOMPSTAT_INC(ipcomps_nopf);
433 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
434 		    "IPCA %s/%08lx\n", __func__,
435 		    sav->sah->saidx.dst.sa.sa_family,
436 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
437 		    (u_long) ntohl(sav->spi)));
438 		error = EPFNOSUPPORT;
439 		goto bad;
440 	}
441 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
442 		IPCOMPSTAT_INC(ipcomps_toobig);
443 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
444 		    "(len %u, max len %u)\n", __func__,
445 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
446 		    (u_long) ntohl(sav->spi),
447 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
448 		error = EMSGSIZE;
449 		goto bad;
450 	}
451 
452 	/* Update the counters */
453 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
454 
455 	m = m_unshare(m, M_NOWAIT);
456 	if (m == NULL) {
457 		IPCOMPSTAT_INC(ipcomps_hdrops);
458 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
459 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
460 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
461 		error = ENOBUFS;
462 		goto bad;
463 	}
464 
465 	/* Ok now, we can pass to the crypto processing. */
466 
467 	/* Get crypto descriptors */
468 	crp = crypto_getreq(1);
469 	if (crp == NULL) {
470 		IPCOMPSTAT_INC(ipcomps_crypto);
471 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
472 		error = ENOBUFS;
473 		goto bad;
474 	}
475 	crdc = crp->crp_desc;
476 
477 	/* Compression descriptor */
478 	crdc->crd_skip = skip;
479 	crdc->crd_len = ralen;
480 	crdc->crd_flags = CRD_F_COMP;
481 	crdc->crd_inject = skip;
482 
483 	/* Compression operation */
484 	crdc->crd_alg = ipcompx->type;
485 
486 	/* IPsec-specific opaque crypto info */
487 	xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
488 	if (xd == NULL) {
489 		IPCOMPSTAT_INC(ipcomps_crypto);
490 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
491 		crypto_freereq(crp);
492 		error = ENOBUFS;
493 		goto bad;
494 	}
495 
496 	xd->sp = sp;
497 	xd->sav = sav;
498 	xd->idx = idx;
499 	xd->skip = skip;
500 	xd->protoff = protoff;
501 	xd->vnet = curvnet;
502 
503 	/* Crypto operation descriptor */
504 	crp->crp_ilen = m->m_pkthdr.len;	/* Total input length */
505 	crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
506 	crp->crp_buf = (caddr_t) m;
507 	crp->crp_callback = ipcomp_output_cb;
508 	crp->crp_opaque = (caddr_t) xd;
509 
510 	SECASVAR_LOCK(sav);
511 	crp->crp_sid = xd->cryptoid = sav->tdb_cryptoid;
512 	SECASVAR_UNLOCK(sav);
513 
514 	return crypto_dispatch(crp);
515 bad:
516 	if (m)
517 		m_freem(m);
518 	key_freesav(&sav);
519 	key_freesp(&sp);
520 	return (error);
521 }
522 
523 /*
524  * IPComp output callback from the crypto driver.
525  */
526 static int
527 ipcomp_output_cb(struct cryptop *crp)
528 {
529 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
530 	struct xform_data *xd;
531 	struct secpolicy *sp;
532 	struct secasvar *sav;
533 	struct mbuf *m;
534 	uint64_t cryptoid;
535 	u_int idx;
536 	int error, skip, protoff;
537 
538 	m = (struct mbuf *) crp->crp_buf;
539 	xd = (struct xform_data *) crp->crp_opaque;
540 	CURVNET_SET(xd->vnet);
541 	idx = xd->idx;
542 	sp = xd->sp;
543 	sav = xd->sav;
544 	skip = xd->skip;
545 	protoff = xd->protoff;
546 	cryptoid = xd->cryptoid;
547 
548 	/* Check for crypto errors */
549 	if (crp->crp_etype) {
550 		if (crp->crp_etype == EAGAIN) {
551 			/* Reset the session ID */
552 			if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
553 				crypto_freesession(cryptoid);
554 			xd->cryptoid = crp->crp_sid;
555 			CURVNET_RESTORE();
556 			return (crypto_dispatch(crp));
557 		}
558 		IPCOMPSTAT_INC(ipcomps_noxform);
559 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
560 		error = crp->crp_etype;
561 		goto bad;
562 	}
563 	/* Shouldn't happen... */
564 	if (m == NULL) {
565 		IPCOMPSTAT_INC(ipcomps_crypto);
566 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
567 		error = EINVAL;
568 		goto bad;
569 	}
570 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
571 
572 	if (crp->crp_ilen - skip > crp->crp_olen) {
573 		struct mbuf *mo;
574 		struct ipcomp *ipcomp;
575 		int roff;
576 		uint8_t prot;
577 
578 		/* Compression helped, inject IPCOMP header. */
579 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
580 		if (mo == NULL) {
581 			IPCOMPSTAT_INC(ipcomps_wrap);
582 			DPRINTF(("%s: IPCOMP header inject failed "
583 			    "for IPCA %s/%08lx\n",
584 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
585 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
586 			error = ENOBUFS;
587 			goto bad;
588 		}
589 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
590 
591 		/* Initialize the IPCOMP header */
592 		/* XXX alignment always correct? */
593 		switch (sav->sah->saidx.dst.sa.sa_family) {
594 #ifdef INET
595 		case AF_INET:
596 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
597 			break;
598 #endif /* INET */
599 #ifdef INET6
600 		case AF_INET6:
601 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
602 			break;
603 #endif
604 		}
605 		ipcomp->comp_flags = 0;
606 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
607 
608 		/* Fix Next Protocol in IPv4/IPv6 header */
609 		prot = IPPROTO_IPCOMP;
610 		m_copyback(m, protoff, sizeof(u_int8_t),
611 		    (u_char *)&prot);
612 
613 		/* Adjust the length in the IP header */
614 		switch (sav->sah->saidx.dst.sa.sa_family) {
615 #ifdef INET
616 		case AF_INET:
617 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
618 			break;
619 #endif /* INET */
620 #ifdef INET6
621 		case AF_INET6:
622 			mtod(m, struct ip6_hdr *)->ip6_plen =
623 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
624 			break;
625 #endif /* INET6 */
626 		default:
627 			IPCOMPSTAT_INC(ipcomps_nopf);
628 			DPRINTF(("%s: unknown/unsupported protocol "
629 			    "family %d, IPCA %s/%08lx\n", __func__,
630 			    sav->sah->saidx.dst.sa.sa_family,
631 			    ipsec_address(&sav->sah->saidx.dst, buf,
632 				sizeof(buf)), (u_long) ntohl(sav->spi)));
633 			error = EPFNOSUPPORT;
634 			goto bad;
635 		}
636 	} else {
637 		/* Compression was useless, we have lost time. */
638 		IPCOMPSTAT_INC(ipcomps_uncompr);
639 		DPRINTF(("%s: compressions was useless %d - %d <= %d\n",
640 		    __func__, crp->crp_ilen, skip, crp->crp_olen));
641 		/* XXX remember state to not compress the next couple
642 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
643 	}
644 
645 	/* Release the crypto descriptor */
646 	free(xd, M_XDATA);
647 	crypto_freereq(crp);
648 
649 	/* NB: m is reclaimed by ipsec_process_done. */
650 	error = ipsec_process_done(m, sp, sav, idx);
651 	CURVNET_RESTORE();
652 	return (error);
653 bad:
654 	if (m)
655 		m_freem(m);
656 	CURVNET_RESTORE();
657 	free(xd, M_XDATA);
658 	crypto_freereq(crp);
659 	key_freesav(&sav);
660 	key_freesp(&sp);
661 	return (error);
662 }
663 
664 #ifdef INET
665 static const struct encaptab *ipe4_cookie = NULL;
666 extern struct domain inetdomain;
667 static struct protosw ipcomp4_protosw = {
668 	.pr_type =	SOCK_RAW,
669 	.pr_domain =	&inetdomain,
670 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
671 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
672 	.pr_input =	ipcomp_nonexp_input,
673 	.pr_output =	rip_output,
674 	.pr_ctloutput =	rip_ctloutput,
675 	.pr_usrreqs =	&rip_usrreqs
676 };
677 
678 static int
679 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
680     void *arg __unused)
681 {
682 	union sockaddr_union src, dst;
683 	const struct ip *ip;
684 
685 	if (V_ipcomp_enable == 0)
686 		return (0);
687 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
688 		return (0);
689 	bzero(&src, sizeof(src));
690 	bzero(&dst, sizeof(dst));
691 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
692 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
693 	ip = mtod(m, const struct ip *);
694 	src.sin.sin_addr = ip->ip_src;
695 	dst.sin.sin_addr = ip->ip_dst;
696 	return (ipcomp_encapcheck(&src, &dst));
697 }
698 #endif
699 #ifdef INET6
700 static const struct encaptab *ipe6_cookie = NULL;
701 extern struct domain inet6domain;
702 static struct protosw ipcomp6_protosw = {
703 	.pr_type =	SOCK_RAW,
704 	.pr_domain =	&inet6domain,
705 	.pr_protocol =	0 /* IPPROTO_IPV[46] */,
706 	.pr_flags =	PR_ATOMIC | PR_ADDR | PR_LASTHDR,
707 	.pr_input =	ipcomp_nonexp_input,
708 	.pr_output =	rip6_output,
709 	.pr_ctloutput =	rip6_ctloutput,
710 	.pr_usrreqs =	&rip6_usrreqs
711 };
712 
713 static int
714 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
715     void *arg __unused)
716 {
717 	union sockaddr_union src, dst;
718 	const struct ip6_hdr *ip6;
719 
720 	if (V_ipcomp_enable == 0)
721 		return (0);
722 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
723 		return (0);
724 	bzero(&src, sizeof(src));
725 	bzero(&dst, sizeof(dst));
726 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
727 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
728 	ip6 = mtod(m, const struct ip6_hdr *);
729 	src.sin6.sin6_addr = ip6->ip6_src;
730 	dst.sin6.sin6_addr = ip6->ip6_dst;
731 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
732 		/* XXX: sa6_recoverscope() */
733 		src.sin6.sin6_scope_id =
734 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
735 		src.sin6.sin6_addr.s6_addr16[1] = 0;
736 	}
737 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
738 		/* XXX: sa6_recoverscope() */
739 		dst.sin6.sin6_scope_id =
740 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
741 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
742 	}
743 	return (ipcomp_encapcheck(&src, &dst));
744 }
745 #endif
746 
747 static struct xformsw ipcomp_xformsw = {
748 	.xf_type =	XF_IPCOMP,
749 	.xf_name =	"IPcomp",
750 	.xf_init =	ipcomp_init,
751 	.xf_zeroize =	ipcomp_zeroize,
752 	.xf_input =	ipcomp_input,
753 	.xf_output =	ipcomp_output,
754 };
755 
756 static void
757 ipcomp_attach(void)
758 {
759 
760 #ifdef INET
761 	ipe4_cookie = encap_attach_func(AF_INET, -1,
762 	    ipcomp4_nonexp_encapcheck, &ipcomp4_protosw, NULL);
763 #endif
764 #ifdef INET6
765 	ipe6_cookie = encap_attach_func(AF_INET6, -1,
766 	    ipcomp6_nonexp_encapcheck, &ipcomp6_protosw, NULL);
767 #endif
768 	xform_attach(&ipcomp_xformsw);
769 }
770 
771 static void
772 ipcomp_detach(void)
773 {
774 
775 #ifdef INET
776 	encap_detach(ipe4_cookie);
777 #endif
778 #ifdef INET6
779 	encap_detach(ipe6_cookie);
780 #endif
781 	xform_detach(&ipcomp_xformsw);
782 }
783 
784 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
785     ipcomp_attach, NULL);
786 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
787     ipcomp_detach, NULL);
788