1 /* $FreeBSD: releng/6.0/sys/netinet6/ipcomp_output.c 139826 2005-01-07 02:30:35Z imp $ */
2 /* $KAME: ipcomp_output.c,v 1.25 2002/06/09 14:44:00 itojun Exp $ */
3
4 /*-
5 * Copyright (C) 1999 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * RFC2393 IP payload compression protocol (IPComp).
35 */
36
37 #include "opt_inet.h"
38 #include "opt_inet6.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/malloc.h>
43 #include <sys/mbuf.h>
44 #include <sys/domain.h>
45 #include <sys/protosw.h>
46 #include <sys/socket.h>
47 #include <sys/errno.h>
48 #include <sys/time.h>
49 #include <sys/syslog.h>
50
51 #include <net/if.h>
52 #include <net/route.h>
53 #include <net/netisr.h>
54 #include <net/zlib.h>
55 #include <machine/cpu.h>
56
57 #include <netinet/in.h>
58 #include <netinet/in_systm.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/ip_ecn.h>
63
64 #ifdef INET6
65 #include <netinet/ip6.h>
66 #include <netinet6/ip6_var.h>
67 #endif
68 #include <netinet6/ipcomp.h>
69 #ifdef INET6
70 #include <netinet6/ipcomp6.h>
71 #endif
72
73 #include <netinet6/ipsec.h>
74 #ifdef INET6
75 #include <netinet6/ipsec6.h>
76 #endif
77 #include <netkey/key.h>
78 #include <netkey/keydb.h>
79
80 #include <machine/stdarg.h>
81
82 #include <net/net_osdep.h>
83
84 static int ipcomp_output __P((struct mbuf *, u_char *, struct mbuf *,
85 struct ipsecrequest *, int));
86
87 /*
88 * Modify the packet so that the payload is compressed.
89 * The mbuf (m) must start with IPv4 or IPv6 header.
90 * On failure, free the given mbuf and return non-zero.
91 *
92 * on invocation:
93 * m nexthdrp md
94 * v v v
95 * IP ......... payload
96 * during the encryption:
97 * m nexthdrp mprev md
98 * v v v v
99 * IP ............... ipcomp payload
100 * <-----><----->
101 * complen plen
102 * <-> hlen
103 * <-----------------> compoff
104 */
105 static int
106 ipcomp_output(m, nexthdrp, md, isr, af)
107 struct mbuf *m;
108 u_char *nexthdrp;
109 struct mbuf *md;
110 struct ipsecrequest *isr;
111 int af;
112 {
113 struct mbuf *n;
114 struct mbuf *md0;
115 struct mbuf *mcopy;
116 struct mbuf *mprev;
117 struct ipcomp *ipcomp;
118 struct secasvar *sav = isr->sav;
119 const struct ipcomp_algorithm *algo;
120 u_int16_t cpi; /* host order */
121 size_t plen0, plen; /* payload length to be compressed */
122 size_t compoff;
123 int afnumber;
124 int error = 0;
125 struct ipsecstat *stat;
126
127 switch (af) {
128 #ifdef INET
129 case AF_INET:
130 afnumber = 4;
131 stat = &ipsecstat;
132 break;
133 #endif
134 #ifdef INET6
135 case AF_INET6:
136 afnumber = 6;
137 stat = &ipsec6stat;
138 break;
139 #endif
140 default:
141 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
142 return 0; /* no change at all */
143 }
144
145 /* grab parameters */
146 algo = ipcomp_algorithm_lookup(sav->alg_enc);
147 if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
148 stat->out_inval++;
149 m_freem(m);
150 return EINVAL;
151 }
152 if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
153 cpi = sav->alg_enc;
154 else
155 cpi = ntohl(sav->spi) & 0xffff;
156
157 /* compute original payload length */
158 plen = 0;
159 for (n = md; n; n = n->m_next)
160 plen += n->m_len;
161
162 /* if the payload is short enough, we don't need to compress */
163 if (plen < algo->minplen)
164 return 0;
165
166 /*
167 * retain the original packet for two purposes:
168 * (1) we need to backout our changes when compression is not necessary.
169 * (2) byte lifetime computation should use the original packet.
170 * see RFC2401 page 23.
171 * compromise two m_copym(). we will be going through every byte of
172 * the payload during compression process anyways.
173 */
174 mcopy = m_copym(m, 0, M_COPYALL, M_DONTWAIT);
175 if (mcopy == NULL) {
176 error = ENOBUFS;
177 return 0;
178 }
179 md0 = m_copym(md, 0, M_COPYALL, M_DONTWAIT);
180 if (md0 == NULL) {
181 m_freem(mcopy);
182 error = ENOBUFS;
183 return 0;
184 }
185 plen0 = plen;
186
187 /* make the packet over-writable */
188 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
189 ;
190 if (mprev == NULL || mprev->m_next != md) {
191 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
192 afnumber));
193 stat->out_inval++;
194 m_freem(m);
195 m_freem(md0);
196 m_freem(mcopy);
197 return EINVAL;
198 }
199 mprev->m_next = NULL;
200 if ((md = ipsec_copypkt(md)) == NULL) {
201 m_freem(m);
202 m_freem(md0);
203 m_freem(mcopy);
204 error = ENOBUFS;
205 goto fail;
206 }
207 mprev->m_next = md;
208
209 /* compress data part */
210 if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
211 ipseclog((LOG_ERR, "packet compression failure\n"));
212 m = NULL;
213 m_freem(md0);
214 m_freem(mcopy);
215 stat->out_inval++;
216 error = EINVAL;
217 goto fail;
218 }
219 stat->out_comphist[sav->alg_enc]++;
220 md = mprev->m_next;
221
222 /*
223 * if the packet became bigger, meaningless to use IPComp.
224 * we've only wasted our cpu time.
225 */
226 if (plen0 < plen) {
227 m_freem(md);
228 m_freem(mcopy);
229 mprev->m_next = md0;
230 return 0;
231 }
232
233 /*
234 * no need to backout change beyond here.
235 */
236 m_freem(md0);
237 md0 = NULL;
238
239 m->m_pkthdr.len -= plen0;
240 m->m_pkthdr.len += plen;
241
242 {
243 /*
244 * insert IPComp header.
245 */
246 #ifdef INET
247 struct ip *ip = NULL;
248 #endif
249 #ifdef INET6
250 struct ip6_hdr *ip6 = NULL;
251 #endif
252 size_t hlen = 0; /* ip header len */
253 size_t complen = sizeof(struct ipcomp);
254
255 switch (af) {
256 #ifdef INET
257 case AF_INET:
258 ip = mtod(m, struct ip *);
259 #ifdef _IP_VHL
260 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
261 #else
262 hlen = ip->ip_hl << 2;
263 #endif
264 break;
265 #endif
266 #ifdef INET6
267 case AF_INET6:
268 ip6 = mtod(m, struct ip6_hdr *);
269 hlen = sizeof(*ip6);
270 break;
271 #endif
272 }
273
274 compoff = m->m_pkthdr.len - plen;
275
276 /*
277 * grow the mbuf to accomodate ipcomp header.
278 * before: IP ... payload
279 * after: IP ... ipcomp payload
280 */
281 if (M_LEADINGSPACE(md) < complen) {
282 MGET(n, M_DONTWAIT, MT_DATA);
283 if (!n) {
284 m_freem(m);
285 error = ENOBUFS;
286 goto fail;
287 }
288 n->m_len = complen;
289 mprev->m_next = n;
290 n->m_next = md;
291 m->m_pkthdr.len += complen;
292 ipcomp = mtod(n, struct ipcomp *);
293 } else {
294 md->m_len += complen;
295 md->m_data -= complen;
296 m->m_pkthdr.len += complen;
297 ipcomp = mtod(md, struct ipcomp *);
298 }
299
300 bzero(ipcomp, sizeof(*ipcomp));
301 ipcomp->comp_nxt = *nexthdrp;
302 *nexthdrp = IPPROTO_IPCOMP;
303 ipcomp->comp_cpi = htons(cpi);
304 switch (af) {
305 #ifdef INET
306 case AF_INET:
307 if (compoff + complen + plen < IP_MAXPACKET)
308 ip->ip_len = htons(compoff + complen + plen);
309 else {
310 ipseclog((LOG_ERR,
311 "IPv4 ESP output: size exceeds limit\n"));
312 ipsecstat.out_inval++;
313 m_freem(m);
314 error = EMSGSIZE;
315 goto fail;
316 }
317 break;
318 #endif
319 #ifdef INET6
320 case AF_INET6:
321 /* total packet length will be computed in ip6_output() */
322 break;
323 #endif
324 }
325 }
326
327 if (!m) {
328 ipseclog((LOG_DEBUG,
329 "NULL mbuf after compression in ipcomp%d_output",
330 afnumber));
331 stat->out_inval++;
332 }
333 stat->out_success++;
334
335 /* compute byte lifetime against original packet */
336 key_sa_recordxfer(sav, mcopy);
337 m_freem(mcopy);
338
339 return 0;
340
341 fail:
342 #if 1
343 return error;
344 #else
345 panic("something bad in ipcomp_output");
346 #endif
347 }
348
349 #ifdef INET
350 int
351 ipcomp4_output(m, isr)
352 struct mbuf *m;
353 struct ipsecrequest *isr;
354 {
355 struct ip *ip;
356 if (m->m_len < sizeof(struct ip)) {
357 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
358 ipsecstat.out_inval++;
359 m_freem(m);
360 return 0;
361 }
362 ip = mtod(m, struct ip *);
363 /* XXX assumes that m->m_next points to payload */
364 return ipcomp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
365 }
366 #endif /* INET */
367
368 #ifdef INET6
369 int
370 ipcomp6_output(m, nexthdrp, md, isr)
371 struct mbuf *m;
372 u_char *nexthdrp;
373 struct mbuf *md;
374 struct ipsecrequest *isr;
375 {
376 if (m->m_len < sizeof(struct ip6_hdr)) {
377 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
378 ipsec6stat.out_inval++;
379 m_freem(m);
380 return 0;
381 }
382 return ipcomp_output(m, nexthdrp, md, isr, AF_INET6);
383 }
384 #endif /* INET6 */
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