xref: /freebsd/sys/netipsec/xform_ipcomp.c (revision cfd6422a5217410fbd66f7a7a8a64d9d85e61229)
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 #include "opt_ipsec.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/socket.h>
44 #include <sys/kernel.h>
45 #include <sys/protosw.h>
46 #include <sys/sysctl.h>
47 
48 #include <netinet/in.h>
49 #include <netinet/in_systm.h>
50 #include <netinet/ip.h>
51 #include <netinet/ip_var.h>
52 #include <netinet/ip_encap.h>
53 
54 #include <net/netisr.h>
55 #include <net/vnet.h>
56 #include <net/if.h>	/* XXXGL: net_epoch should move out there */
57 #include <net/if_var.h>	/* XXXGL: net_epoch should move out there */
58 
59 #include <netipsec/ipsec.h>
60 #include <netipsec/xform.h>
61 
62 #ifdef INET6
63 #include <netinet/ip6.h>
64 #include <netinet6/ip6_var.h>
65 #include <netipsec/ipsec6.h>
66 #endif
67 
68 #include <netipsec/ipcomp.h>
69 #include <netipsec/ipcomp_var.h>
70 
71 #include <netipsec/key.h>
72 #include <netipsec/key_debug.h>
73 
74 #include <opencrypto/cryptodev.h>
75 #include <opencrypto/deflate.h>
76 #include <opencrypto/xform.h>
77 
78 VNET_DEFINE(int, ipcomp_enable) = 1;
79 VNET_PCPUSTAT_DEFINE(struct ipcompstat, ipcompstat);
80 VNET_PCPUSTAT_SYSINIT(ipcompstat);
81 
82 #ifdef VIMAGE
83 VNET_PCPUSTAT_SYSUNINIT(ipcompstat);
84 #endif /* VIMAGE */
85 
86 SYSCTL_DECL(_net_inet_ipcomp);
87 SYSCTL_INT(_net_inet_ipcomp, OID_AUTO, ipcomp_enable,
88 	CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ipcomp_enable), 0, "");
89 SYSCTL_VNET_PCPUSTAT(_net_inet_ipcomp, IPSECCTL_STATS, stats,
90     struct ipcompstat, ipcompstat,
91     "IPCOMP statistics (struct ipcompstat, netipsec/ipcomp_var.h");
92 
93 static int ipcomp_input_cb(struct cryptop *crp);
94 static int ipcomp_output_cb(struct cryptop *crp);
95 
96 /*
97  * RFC 3173 p 2.2. Non-Expansion Policy:
98  * If the total size of a compressed payload and the IPComp header, as
99  * defined in section 3, is not smaller than the size of the original
100  * payload, the IP datagram MUST be sent in the original non-compressed
101  * form.
102  *
103  * When we use IPComp in tunnel mode, for small packets we will receive
104  * encapsulated IP-IP datagrams without any compression and without IPComp
105  * header.
106  */
107 static int
108 ipcomp_encapcheck(union sockaddr_union *src, union sockaddr_union *dst)
109 {
110 	struct secasvar *sav;
111 
112 	sav = key_allocsa_tunnel(src, dst, IPPROTO_IPCOMP);
113 	if (sav == NULL)
114 		return (0);
115 	key_freesav(&sav);
116 
117 	if (src->sa.sa_family == AF_INET)
118 		return (sizeof(struct in_addr) << 4);
119 	else
120 		return (sizeof(struct in6_addr) << 4);
121 }
122 
123 static int
124 ipcomp_nonexp_input(struct mbuf *m, int off, int proto, void *arg __unused)
125 {
126 	int isr;
127 
128 	NET_EPOCH_ASSERT();
129 
130 	switch (proto) {
131 #ifdef INET
132 	case IPPROTO_IPV4:
133 		isr = NETISR_IP;
134 		break;
135 #endif
136 #ifdef INET6
137 	case IPPROTO_IPV6:
138 		isr = NETISR_IPV6;
139 		break;
140 #endif
141 	default:
142 		IPCOMPSTAT_INC(ipcomps_nopf);
143 		m_freem(m);
144 		return (IPPROTO_DONE);
145 	}
146 	m_adj(m, off);
147 	IPCOMPSTAT_ADD(ipcomps_ibytes, m->m_pkthdr.len);
148 	IPCOMPSTAT_INC(ipcomps_input);
149 	netisr_dispatch(isr, m);
150 	return (IPPROTO_DONE);
151 }
152 
153 /*
154  * ipcomp_init() is called when an CPI is being set up.
155  */
156 static int
157 ipcomp_init(struct secasvar *sav, struct xformsw *xsp)
158 {
159 	const struct comp_algo *tcomp;
160 	struct crypto_session_params csp;
161 
162 	/* NB: algorithm really comes in alg_enc and not alg_comp! */
163 	tcomp = comp_algorithm_lookup(sav->alg_enc);
164 	if (tcomp == NULL) {
165 		DPRINTF(("%s: unsupported compression algorithm %d\n", __func__,
166 			 sav->alg_comp));
167 		return EINVAL;
168 	}
169 	sav->alg_comp = sav->alg_enc;		/* set for doing histogram */
170 	sav->tdb_xform = xsp;
171 	sav->tdb_compalgxform = tcomp;
172 
173 	/* Initialize crypto session */
174 	memset(&csp, 0, sizeof(csp));
175 	csp.csp_mode = CSP_MODE_COMPRESS;
176 	csp.csp_cipher_alg = sav->tdb_compalgxform->type;
177 
178 	return crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
179 }
180 
181 /*
182  * ipcomp_cleanup() used when IPCA is deleted
183  */
184 static void
185 ipcomp_cleanup(struct secasvar *sav)
186 {
187 
188 	crypto_freesession(sav->tdb_cryptoid);
189 	sav->tdb_cryptoid = NULL;
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_flags = CRYPTO_F_CBIFSYNC;
253 	crypto_use_mbuf(crp, m);
254 	crp->crp_callback = ipcomp_input_cb;
255 	crp->crp_opaque = xd;
256 
257 	/* These are passed as-is to the callback */
258 	xd->sav = sav;
259 	xd->protoff = protoff;
260 	xd->skip = skip;
261 	xd->vnet = curvnet;
262 	xd->cryptoid = cryptoid;
263 
264 	SECASVAR_LOCK(sav);
265 	crp->crp_session = xd->cryptoid = sav->tdb_cryptoid;
266 	SECASVAR_UNLOCK(sav);
267 
268 	return crypto_dispatch(crp);
269 bad:
270 	m_freem(m);
271 	key_freesav(&sav);
272 	return (error);
273 }
274 
275 /*
276  * IPComp input callback from the crypto driver.
277  */
278 static int
279 ipcomp_input_cb(struct cryptop *crp)
280 {
281 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
282 	struct xform_data *xd;
283 	struct mbuf *m;
284 	struct secasvar *sav;
285 	struct secasindex *saidx;
286 	caddr_t addr;
287 	crypto_session_t cryptoid;
288 	int hlen = IPCOMP_HLENGTH, error, clen;
289 	int skip, protoff;
290 	uint8_t nproto;
291 
292 	m = crp->crp_buf.cb_mbuf;
293 	xd = crp->crp_opaque;
294 	CURVNET_SET(xd->vnet);
295 	sav = xd->sav;
296 	skip = xd->skip;
297 	protoff = xd->protoff;
298 	cryptoid = xd->cryptoid;
299 	saidx = &sav->sah->saidx;
300 	IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
301 		saidx->dst.sa.sa_family == AF_INET6,
302 		("unexpected protocol family %u", saidx->dst.sa.sa_family));
303 
304 	/* Check for crypto errors */
305 	if (crp->crp_etype) {
306 		if (crp->crp_etype == EAGAIN) {
307 			/* Reset the session ID */
308 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
309 				crypto_freesession(cryptoid);
310 			xd->cryptoid = crp->crp_session;
311 			CURVNET_RESTORE();
312 			return (crypto_dispatch(crp));
313 		}
314 		IPCOMPSTAT_INC(ipcomps_noxform);
315 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
316 		error = crp->crp_etype;
317 		goto bad;
318 	}
319 	/* Shouldn't happen... */
320 	if (m == NULL) {
321 		IPCOMPSTAT_INC(ipcomps_crypto);
322 		DPRINTF(("%s: null mbuf returned from crypto\n", __func__));
323 		error = EINVAL;
324 		goto bad;
325 	}
326 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
327 
328 	clen = crp->crp_olen;		/* Length of data after processing */
329 
330 	/* Release the crypto descriptors */
331 	free(xd, M_XDATA), xd = NULL;
332 	crypto_freereq(crp), crp = NULL;
333 
334 	/* In case it's not done already, adjust the size of the mbuf chain */
335 	m->m_pkthdr.len = clen + hlen + skip;
336 
337 	if (m->m_len < skip + hlen && (m = m_pullup(m, skip + hlen)) == NULL) {
338 		IPCOMPSTAT_INC(ipcomps_hdrops);		/*XXX*/
339 		DPRINTF(("%s: m_pullup failed\n", __func__));
340 		error = EINVAL;				/*XXX*/
341 		goto bad;
342 	}
343 
344 	/* Keep the next protocol field */
345 	addr = (caddr_t) mtod(m, struct ip *) + skip;
346 	nproto = ((struct ipcomp *) addr)->comp_nxt;
347 
348 	/* Remove the IPCOMP header */
349 	error = m_striphdr(m, skip, hlen);
350 	if (error) {
351 		IPCOMPSTAT_INC(ipcomps_hdrops);
352 		DPRINTF(("%s: bad mbuf chain, IPCA %s/%08lx\n", __func__,
353 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
354 		    (u_long) ntohl(sav->spi)));
355 		goto bad;
356 	}
357 
358 	/* Restore the Next Protocol field */
359 	m_copyback(m, protoff, sizeof (u_int8_t), (u_int8_t *) &nproto);
360 
361 	switch (saidx->dst.sa.sa_family) {
362 #ifdef INET6
363 	case AF_INET6:
364 		error = ipsec6_common_input_cb(m, sav, skip, protoff);
365 		break;
366 #endif
367 #ifdef INET
368 	case AF_INET:
369 		error = ipsec4_common_input_cb(m, sav, skip, protoff);
370 		break;
371 #endif
372 	default:
373 		panic("%s: Unexpected address family: %d saidx=%p", __func__,
374 		    saidx->dst.sa.sa_family, saidx);
375 	}
376 	CURVNET_RESTORE();
377 	return error;
378 bad:
379 	CURVNET_RESTORE();
380 	if (sav != NULL)
381 		key_freesav(&sav);
382 	if (m != NULL)
383 		m_freem(m);
384 	if (xd != NULL)
385 		free(xd, M_XDATA);
386 	if (crp != NULL)
387 		crypto_freereq(crp);
388 	return error;
389 }
390 
391 /*
392  * IPComp output routine, called by ipsec[46]_perform_request()
393  */
394 static int
395 ipcomp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
396     u_int idx, int skip, int protoff)
397 {
398 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
399 	const struct comp_algo *ipcompx;
400 	struct cryptop *crp;
401 	struct xform_data *xd;
402 	crypto_session_t cryptoid;
403 	int error, ralen, maxpacketsize;
404 
405 	IPSEC_ASSERT(sav != NULL, ("null SA"));
406 	ipcompx = sav->tdb_compalgxform;
407 	IPSEC_ASSERT(ipcompx != NULL, ("null compression xform"));
408 
409 	/*
410 	 * Do not touch the packet in case our payload to compress
411 	 * is lower than the minimal threshold of the compression
412 	 * alogrithm.  We will just send out the data uncompressed.
413 	 * See RFC 3173, 2.2. Non-Expansion Policy.
414 	 */
415 	if (m->m_pkthdr.len <= ipcompx->minlen) {
416 		IPCOMPSTAT_INC(ipcomps_threshold);
417 		return ipsec_process_done(m, sp, sav, idx);
418 	}
419 
420 	ralen = m->m_pkthdr.len - skip;	/* Raw payload length before comp. */
421 	IPCOMPSTAT_INC(ipcomps_output);
422 
423 	/* Check for maximum packet size violations. */
424 	switch (sav->sah->saidx.dst.sa.sa_family) {
425 #ifdef INET
426 	case AF_INET:
427 		maxpacketsize = IP_MAXPACKET;
428 		break;
429 #endif /* INET */
430 #ifdef INET6
431 	case AF_INET6:
432 		maxpacketsize = IPV6_MAXPACKET;
433 		break;
434 #endif /* INET6 */
435 	default:
436 		IPCOMPSTAT_INC(ipcomps_nopf);
437 		DPRINTF(("%s: unknown/unsupported protocol family %d, "
438 		    "IPCA %s/%08lx\n", __func__,
439 		    sav->sah->saidx.dst.sa.sa_family,
440 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
441 		    (u_long) ntohl(sav->spi)));
442 		error = EPFNOSUPPORT;
443 		goto bad;
444 	}
445 	if (ralen + skip + IPCOMP_HLENGTH > maxpacketsize) {
446 		IPCOMPSTAT_INC(ipcomps_toobig);
447 		DPRINTF(("%s: packet in IPCA %s/%08lx got too big "
448 		    "(len %u, max len %u)\n", __func__,
449 		    ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
450 		    (u_long) ntohl(sav->spi),
451 		    ralen + skip + IPCOMP_HLENGTH, maxpacketsize));
452 		error = EMSGSIZE;
453 		goto bad;
454 	}
455 
456 	/* Update the counters */
457 	IPCOMPSTAT_ADD(ipcomps_obytes, m->m_pkthdr.len - skip);
458 
459 	m = m_unshare(m, M_NOWAIT);
460 	if (m == NULL) {
461 		IPCOMPSTAT_INC(ipcomps_hdrops);
462 		DPRINTF(("%s: cannot clone mbuf chain, IPCA %s/%08lx\n",
463 		    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
464 		    sizeof(buf)), (u_long) ntohl(sav->spi)));
465 		error = ENOBUFS;
466 		goto bad;
467 	}
468 
469 	/* Ok now, we can pass to the crypto processing. */
470 	SECASVAR_LOCK(sav);
471 	cryptoid = sav->tdb_cryptoid;
472 	SECASVAR_UNLOCK(sav);
473 
474 	/* Get crypto descriptors */
475 	crp = crypto_getreq(cryptoid, M_NOWAIT);
476 	if (crp == NULL) {
477 		IPCOMPSTAT_INC(ipcomps_crypto);
478 		DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__));
479 		error = ENOBUFS;
480 		goto bad;
481 	}
482 
483 	/* Compression descriptor */
484 	crp->crp_op = CRYPTO_OP_COMPRESS;
485 	crp->crp_payload_start = skip;
486 	crp->crp_payload_length = ralen;
487 
488 	/* IPsec-specific opaque crypto info */
489 	xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
490 	if (xd == NULL) {
491 		IPCOMPSTAT_INC(ipcomps_crypto);
492 		DPRINTF(("%s: failed to allocate xform_data\n", __func__));
493 		crypto_freereq(crp);
494 		error = ENOBUFS;
495 		goto bad;
496 	}
497 
498 	xd->sp = sp;
499 	xd->sav = sav;
500 	xd->idx = idx;
501 	xd->skip = skip;
502 	xd->protoff = protoff;
503 	xd->vnet = curvnet;
504 	xd->cryptoid = cryptoid;
505 
506 	/* Crypto operation descriptor */
507 	crp->crp_flags = CRYPTO_F_CBIFSYNC;
508 	crypto_use_mbuf(crp, m);
509 	crp->crp_callback = ipcomp_output_cb;
510 	crp->crp_opaque = xd;
511 
512 	return crypto_dispatch(crp);
513 bad:
514 	if (m)
515 		m_freem(m);
516 	key_freesav(&sav);
517 	key_freesp(&sp);
518 	return (error);
519 }
520 
521 /*
522  * IPComp output callback from the crypto driver.
523  */
524 static int
525 ipcomp_output_cb(struct cryptop *crp)
526 {
527 	IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
528 	struct xform_data *xd;
529 	struct secpolicy *sp;
530 	struct secasvar *sav;
531 	struct mbuf *m;
532 	crypto_session_t cryptoid;
533 	u_int idx;
534 	int error, skip, protoff;
535 
536 	m = crp->crp_buf.cb_mbuf;
537 	xd = crp->crp_opaque;
538 	CURVNET_SET(xd->vnet);
539 	idx = xd->idx;
540 	sp = xd->sp;
541 	sav = xd->sav;
542 	skip = xd->skip;
543 	protoff = xd->protoff;
544 	cryptoid = xd->cryptoid;
545 
546 	/* Check for crypto errors */
547 	if (crp->crp_etype) {
548 		if (crp->crp_etype == EAGAIN) {
549 			/* Reset the session ID */
550 			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
551 				crypto_freesession(cryptoid);
552 			xd->cryptoid = crp->crp_session;
553 			CURVNET_RESTORE();
554 			return (crypto_dispatch(crp));
555 		}
556 		IPCOMPSTAT_INC(ipcomps_noxform);
557 		DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
558 		error = crp->crp_etype;
559 		goto bad;
560 	}
561 	/* Shouldn't happen... */
562 	if (m == NULL) {
563 		IPCOMPSTAT_INC(ipcomps_crypto);
564 		DPRINTF(("%s: bogus return buffer from crypto\n", __func__));
565 		error = EINVAL;
566 		goto bad;
567 	}
568 	IPCOMPSTAT_INC(ipcomps_hist[sav->alg_comp]);
569 
570 	if (crp->crp_payload_length > crp->crp_olen) {
571 		struct mbuf *mo;
572 		struct ipcomp *ipcomp;
573 		int roff;
574 		uint8_t prot;
575 
576 		/* Compression helped, inject IPCOMP header. */
577 		mo = m_makespace(m, skip, IPCOMP_HLENGTH, &roff);
578 		if (mo == NULL) {
579 			IPCOMPSTAT_INC(ipcomps_wrap);
580 			DPRINTF(("%s: IPCOMP header inject failed "
581 			    "for IPCA %s/%08lx\n",
582 			    __func__, ipsec_address(&sav->sah->saidx.dst, buf,
583 			    sizeof(buf)), (u_long) ntohl(sav->spi)));
584 			error = ENOBUFS;
585 			goto bad;
586 		}
587 		ipcomp = (struct ipcomp *)(mtod(mo, caddr_t) + roff);
588 
589 		/* Initialize the IPCOMP header */
590 		/* XXX alignment always correct? */
591 		switch (sav->sah->saidx.dst.sa.sa_family) {
592 #ifdef INET
593 		case AF_INET:
594 			ipcomp->comp_nxt = mtod(m, struct ip *)->ip_p;
595 			break;
596 #endif /* INET */
597 #ifdef INET6
598 		case AF_INET6:
599 			ipcomp->comp_nxt = mtod(m, struct ip6_hdr *)->ip6_nxt;
600 			break;
601 #endif
602 		}
603 		ipcomp->comp_flags = 0;
604 		ipcomp->comp_cpi = htons((u_int16_t) ntohl(sav->spi));
605 
606 		/* Fix Next Protocol in IPv4/IPv6 header */
607 		prot = IPPROTO_IPCOMP;
608 		m_copyback(m, protoff, sizeof(u_int8_t),
609 		    (u_char *)&prot);
610 
611 		/* Adjust the length in the IP header */
612 		switch (sav->sah->saidx.dst.sa.sa_family) {
613 #ifdef INET
614 		case AF_INET:
615 			mtod(m, struct ip *)->ip_len = htons(m->m_pkthdr.len);
616 			break;
617 #endif /* INET */
618 #ifdef INET6
619 		case AF_INET6:
620 			mtod(m, struct ip6_hdr *)->ip6_plen =
621 				htons(m->m_pkthdr.len) - sizeof(struct ip6_hdr);
622 			break;
623 #endif /* INET6 */
624 		default:
625 			IPCOMPSTAT_INC(ipcomps_nopf);
626 			DPRINTF(("%s: unknown/unsupported protocol "
627 			    "family %d, IPCA %s/%08lx\n", __func__,
628 			    sav->sah->saidx.dst.sa.sa_family,
629 			    ipsec_address(&sav->sah->saidx.dst, buf,
630 				sizeof(buf)), (u_long) ntohl(sav->spi)));
631 			error = EPFNOSUPPORT;
632 			goto bad;
633 		}
634 	} else {
635 		/* Compression was useless, we have lost time. */
636 		IPCOMPSTAT_INC(ipcomps_uncompr);
637 		DPRINTF(("%s: compressions was useless %d <= %d\n",
638 		    __func__, crp->crp_payload_length, crp->crp_olen));
639 		/* XXX remember state to not compress the next couple
640 		 *     of packets, RFC 3173, 2.2. Non-Expansion Policy */
641 	}
642 
643 	/* Release the crypto descriptor */
644 	free(xd, M_XDATA);
645 	crypto_freereq(crp);
646 
647 	/* NB: m is reclaimed by ipsec_process_done. */
648 	error = ipsec_process_done(m, sp, sav, idx);
649 	CURVNET_RESTORE();
650 	return (error);
651 bad:
652 	if (m)
653 		m_freem(m);
654 	CURVNET_RESTORE();
655 	free(xd, M_XDATA);
656 	crypto_freereq(crp);
657 	key_freesav(&sav);
658 	key_freesp(&sp);
659 	return (error);
660 }
661 
662 #ifdef INET
663 static int
664 ipcomp4_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
665     void *arg __unused)
666 {
667 	union sockaddr_union src, dst;
668 	const struct ip *ip;
669 
670 	if (V_ipcomp_enable == 0)
671 		return (0);
672 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
673 		return (0);
674 	bzero(&src, sizeof(src));
675 	bzero(&dst, sizeof(dst));
676 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
677 	src.sin.sin_len = dst.sin.sin_len = sizeof(struct sockaddr_in);
678 	ip = mtod(m, const struct ip *);
679 	src.sin.sin_addr = ip->ip_src;
680 	dst.sin.sin_addr = ip->ip_dst;
681 	return (ipcomp_encapcheck(&src, &dst));
682 }
683 
684 static const struct encaptab *ipe4_cookie = NULL;
685 static const struct encap_config ipv4_encap_cfg = {
686 	.proto = -1,
687 	.min_length = sizeof(struct ip),
688 	.exact_match = sizeof(in_addr_t) << 4,
689 	.check = ipcomp4_nonexp_encapcheck,
690 	.input = ipcomp_nonexp_input
691 };
692 #endif
693 #ifdef INET6
694 static int
695 ipcomp6_nonexp_encapcheck(const struct mbuf *m, int off, int proto,
696     void *arg __unused)
697 {
698 	union sockaddr_union src, dst;
699 	const struct ip6_hdr *ip6;
700 
701 	if (V_ipcomp_enable == 0)
702 		return (0);
703 	if (proto != IPPROTO_IPV4 && proto != IPPROTO_IPV6)
704 		return (0);
705 	bzero(&src, sizeof(src));
706 	bzero(&dst, sizeof(dst));
707 	src.sa.sa_family = dst.sa.sa_family = AF_INET;
708 	src.sin6.sin6_len = dst.sin6.sin6_len = sizeof(struct sockaddr_in6);
709 	ip6 = mtod(m, const struct ip6_hdr *);
710 	src.sin6.sin6_addr = ip6->ip6_src;
711 	dst.sin6.sin6_addr = ip6->ip6_dst;
712 	if (IN6_IS_SCOPE_LINKLOCAL(&src.sin6.sin6_addr)) {
713 		/* XXX: sa6_recoverscope() */
714 		src.sin6.sin6_scope_id =
715 		    ntohs(src.sin6.sin6_addr.s6_addr16[1]);
716 		src.sin6.sin6_addr.s6_addr16[1] = 0;
717 	}
718 	if (IN6_IS_SCOPE_LINKLOCAL(&dst.sin6.sin6_addr)) {
719 		/* XXX: sa6_recoverscope() */
720 		dst.sin6.sin6_scope_id =
721 		    ntohs(dst.sin6.sin6_addr.s6_addr16[1]);
722 		dst.sin6.sin6_addr.s6_addr16[1] = 0;
723 	}
724 	return (ipcomp_encapcheck(&src, &dst));
725 }
726 
727 static const struct encaptab *ipe6_cookie = NULL;
728 static const struct encap_config ipv6_encap_cfg = {
729 	.proto = -1,
730 	.min_length = sizeof(struct ip6_hdr),
731 	.exact_match = sizeof(struct in6_addr) << 4,
732 	.check = ipcomp6_nonexp_encapcheck,
733 	.input = ipcomp_nonexp_input
734 };
735 #endif
736 
737 static struct xformsw ipcomp_xformsw = {
738 	.xf_type =	XF_IPCOMP,
739 	.xf_name =	"IPcomp",
740 	.xf_init =	ipcomp_init,
741 	.xf_cleanup =	ipcomp_cleanup,
742 	.xf_input =	ipcomp_input,
743 	.xf_output =	ipcomp_output,
744 };
745 
746 static void
747 ipcomp_attach(void)
748 {
749 
750 #ifdef INET
751 	ipe4_cookie = ip_encap_attach(&ipv4_encap_cfg, NULL, M_WAITOK);
752 #endif
753 #ifdef INET6
754 	ipe6_cookie = ip6_encap_attach(&ipv6_encap_cfg, NULL, M_WAITOK);
755 #endif
756 	xform_attach(&ipcomp_xformsw);
757 }
758 
759 static void
760 ipcomp_detach(void)
761 {
762 
763 #ifdef INET
764 	ip_encap_detach(ipe4_cookie);
765 #endif
766 #ifdef INET6
767 	ip6_encap_detach(ipe6_cookie);
768 #endif
769 	xform_detach(&ipcomp_xformsw);
770 }
771 
772 SYSINIT(ipcomp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
773     ipcomp_attach, NULL);
774 SYSUNINIT(ipcomp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
775     ipcomp_detach, NULL);
776