1 /* $NetBSD: ipcomp_output.c,v 1.20.2.1 2007/09/25 00:45:48 xtraeme Exp $ */
2 /* $KAME: ipcomp_output.c,v 1.24 2001/07/26 06:53:18 jinmei 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 <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: ipcomp_output.c,v 1.20.2.1 2007/09/25 00:45:48 xtraeme Exp $");
39
40 #include "opt_inet.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/domain.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
49 #include <sys/errno.h>
50 #include <sys/time.h>
51 #include <sys/kernel.h>
52 #include <sys/syslog.h>
53
54 #include <net/if.h>
55 #include <net/route.h>
56 #include <net/netisr.h>
57 #include <net/zlib.h>
58 #include <machine/cpu.h>
59
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/in_var.h>
63 #include <netinet/ip.h>
64 #include <netinet/ip_var.h>
65 #include <netinet/ip_ecn.h>
66
67 #ifdef INET6
68 #include <netinet/ip6.h>
69 #include <netinet6/ip6_var.h>
70 #endif
71 #include <netinet6/ipcomp.h>
72
73 #include <netinet6/ipsec.h>
74 #include <netkey/key.h>
75 #include <netkey/keydb.h>
76
77 #include <machine/stdarg.h>
78
79 #include <net/net_osdep.h>
80
81 static int ipcomp_output __P((struct mbuf *, u_char *, struct mbuf *,
82 struct ipsecrequest *, int));
83
84 /*
85 * Modify the packet so that the payload is compressed.
86 * The mbuf (m) must start with IPv4 or IPv6 header.
87 * On failure, free the given mbuf and return non-zero.
88 *
89 * on invocation:
90 * m nexthdrp md
91 * v v v
92 * IP ......... payload
93 * during the encryption:
94 * m nexthdrp mprev md
95 * v v v v
96 * IP ............... ipcomp payload
97 * <-----><----->
98 * complen plen
99 * <-> hlen
100 * <-----------------> compoff
101 */
102 static int
103 ipcomp_output(m, nexthdrp, md, isr, af)
104 struct mbuf *m;
105 u_char *nexthdrp;
106 struct mbuf *md;
107 struct ipsecrequest *isr;
108 int af;
109 {
110 struct mbuf *n;
111 struct mbuf *md0;
112 struct mbuf *mcopy;
113 struct mbuf *mprev;
114 struct ipcomp *ipcomp;
115 struct secasvar *sav = isr->sav;
116 const struct ipcomp_algorithm *algo;
117 u_int16_t cpi; /* host order */
118 size_t plen0, plen; /* payload length to be compressed */
119 size_t compoff;
120 int afnumber;
121 int error = 0;
122 struct ipsecstat *stat;
123
124 switch (af) {
125 #ifdef INET
126 case AF_INET:
127 afnumber = 4;
128 stat = &ipsecstat;
129 break;
130 #endif
131 #ifdef INET6
132 case AF_INET6:
133 afnumber = 6;
134 stat = &ipsec6stat;
135 break;
136 #endif
137 default:
138 ipseclog((LOG_ERR, "ipcomp_output: unsupported af %d\n", af));
139 return 0; /* no change at all */
140 }
141
142 /* grab parameters */
143 algo = ipcomp_algorithm_lookup(sav->alg_enc);
144 if ((ntohl(sav->spi) & ~0xffff) != 0 || !algo) {
145 stat->out_inval++;
146 error = EINVAL;
147 goto fail1;
148 }
149 if ((sav->flags & SADB_X_EXT_RAWCPI) == 0)
150 cpi = sav->alg_enc;
151 else
152 cpi = ntohl(sav->spi) & 0xffff;
153
154 /* compute original payload length */
155 plen = 0;
156 for (n = md; n; n = n->m_next)
157 plen += n->m_len;
158
159 /* if the payload is short enough, we don't need to compress */
160 if (plen < algo->minplen)
161 return 0;
162
163 /*
164 * retain the original packet for two purposes:
165 * (1) we need to backout our changes when compression is not necessary.
166 * (2) byte lifetime computation should use the original packet.
167 * see RFC2401 page 23.
168 * compromise two m_copym(). we will be going through every byte of
169 * the payload during compression process anyways.
170 */
171 mcopy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
172 if (mcopy == NULL) {
173 error = ENOBUFS;
174 goto fail1;
175 }
176 md0 = m_copym(md, 0, M_COPYALL, M_NOWAIT);
177 if (md0 == NULL) {
178 error = ENOBUFS;
179 goto fail2;
180 }
181 plen0 = plen;
182
183 /* make the packet over-writable */
184 for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next)
185 ;
186 if (mprev == NULL || mprev->m_next != md) {
187 ipseclog((LOG_DEBUG, "ipcomp%d_output: md is not in chain\n",
188 afnumber));
189 stat->out_inval++;
190 error = EINVAL;
191 goto fail3;
192 }
193 mprev->m_next = NULL;
194 if ((md = ipsec_copypkt(md)) == NULL) {
195 error = ENOBUFS;
196 goto fail3;
197 }
198 mprev->m_next = md;
199
200 /* compress data part */
201 if ((*algo->compress)(m, md, &plen) || mprev->m_next == NULL) {
202 ipseclog((LOG_ERR, "packet compression failure\n"));
203 m = NULL;
204 stat->out_inval++;
205 error = EINVAL;
206 goto fail3;
207 }
208 stat->out_comphist[sav->alg_enc]++;
209 md = mprev->m_next;
210
211 /*
212 * if the packet became bigger, meaningless to use IPComp.
213 * we've only wasted our CPU time.
214 */
215 if (plen0 < plen) {
216 m_freem(md);
217 m_freem(mcopy);
218 mprev->m_next = md0;
219 return 0;
220 }
221
222 /*
223 * no need to backout change beyond here.
224 */
225 m_freem(md0);
226 md0 = NULL;
227
228 m->m_pkthdr.len -= plen0;
229 m->m_pkthdr.len += plen;
230
231 {
232 /*
233 * insert IPComp header.
234 */
235 #ifdef INET
236 struct ip *ip = NULL;
237 #endif
238 #ifdef INET6
239 struct ip6_hdr *ip6 = NULL;
240 #endif
241 size_t hlen = 0; /* ip header len */
242 size_t complen = sizeof(struct ipcomp);
243
244 switch (af) {
245 #ifdef INET
246 case AF_INET:
247 ip = mtod(m, struct ip *);
248 #ifdef _IP_VHL
249 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
250 #else
251 hlen = ip->ip_hl << 2;
252 #endif
253 break;
254 #endif
255 #ifdef INET6
256 case AF_INET6:
257 ip6 = mtod(m, struct ip6_hdr *);
258 hlen = sizeof(*ip6);
259 break;
260 #endif
261 }
262
263 compoff = m->m_pkthdr.len - plen;
264
265 /*
266 * grow the mbuf to accommodate ipcomp header.
267 * before: IP ... payload
268 * after: IP ... ipcomp payload
269 */
270 if (M_LEADINGSPACE(md) < complen) {
271 MGET(n, M_DONTWAIT, MT_DATA);
272 if (!n) {
273 error = ENOBUFS;
274 goto fail2;
275 }
276 n->m_len = complen;
277 mprev->m_next = n;
278 n->m_next = md;
279 m->m_pkthdr.len += complen;
280 ipcomp = mtod(n, struct ipcomp *);
281 } else {
282 md->m_len += complen;
283 md->m_data -= complen;
284 m->m_pkthdr.len += complen;
285 ipcomp = mtod(md, struct ipcomp *);
286 }
287
288 bzero(ipcomp, sizeof(*ipcomp));
289 ipcomp->comp_nxt = *nexthdrp;
290 *nexthdrp = IPPROTO_IPCOMP;
291 ipcomp->comp_cpi = htons(cpi);
292 switch (af) {
293 #ifdef INET
294 case AF_INET:
295 if (compoff + complen + plen < IP_MAXPACKET)
296 ip->ip_len = htons(compoff + complen + plen);
297 else {
298 ipseclog((LOG_ERR,
299 "IPv4 ESP output: size exceeds limit\n"));
300 ipsecstat.out_inval++;
301 error = EMSGSIZE;
302 goto fail2;
303 }
304 break;
305 #endif
306 #ifdef INET6
307 case AF_INET6:
308 /* total packet length will be computed in ip6_output() */
309 break;
310 #endif
311 }
312 }
313
314 if (!m) {
315 ipseclog((LOG_DEBUG,
316 "NULL mbuf after compression in ipcomp%d_output",
317 afnumber));
318 stat->out_inval++;
319 }
320 stat->out_success++;
321
322 /* compute byte lifetime against original packet */
323 key_sa_recordxfer(sav, mcopy);
324 m_freem(mcopy);
325
326 return 0;
327
328 fail3:
329 m_freem(md0);
330 fail2:
331 m_freem(mcopy);
332 fail1:
333 m_freem(m);
334 #if 1
335 return error;
336 #else
337 panic("something bad in ipcomp_output");
338 #endif
339 }
340
341 #ifdef INET
342 int
343 ipcomp4_output(m, isr)
344 struct mbuf *m;
345 struct ipsecrequest *isr;
346 {
347 struct ip *ip;
348 if (m->m_len < sizeof(struct ip)) {
349 ipseclog((LOG_DEBUG, "ipcomp4_output: first mbuf too short\n"));
350 ipsecstat.out_inval++;
351 m_freem(m);
352 return EINVAL;
353 }
354 ip = mtod(m, struct ip *);
355 /* XXX assumes that m->m_next points to payload */
356 return ipcomp_output(m, &ip->ip_p, m->m_next, isr, AF_INET);
357 }
358 #endif /* INET */
359
360 #ifdef INET6
361 int
362 ipcomp6_output(m, nexthdrp, md, isr)
363 struct mbuf *m;
364 u_char *nexthdrp;
365 struct mbuf *md;
366 struct ipsecrequest *isr;
367 {
368 if (m->m_len < sizeof(struct ip6_hdr)) {
369 ipseclog((LOG_DEBUG, "ipcomp6_output: first mbuf too short\n"));
370 ipsec6stat.out_inval++;
371 m_freem(m);
372 return EINVAL;
373 }
374 return ipcomp_output(m, nexthdrp, md, isr, AF_INET6);
375 }
376 #endif /* INET6 */
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