blob: a2860e35efd7d68ee67d3839e4b064aa6f3a574e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
3 *
4 * Copyright (C)2003 USAGI/WIDE Project
5 *
6 * Author Mitsuru KANDA <mk@linux-ipv6.org>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22/*
23 * [Memo]
24 *
25 * Outbound:
26 * The compression of IP datagram MUST be done before AH/ESP processing,
27 * fragmentation, and the addition of Hop-by-Hop/Routing header.
28 *
29 * Inbound:
30 * The decompression of IP datagram MUST be done after the reassembly,
31 * AH/ESP processing.
32 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <linux/module.h>
34#include <net/ip.h>
35#include <net/xfrm.h>
36#include <net/ipcomp.h>
37#include <asm/scatterlist.h>
38#include <asm/semaphore.h>
39#include <linux/crypto.h>
40#include <linux/pfkeyv2.h>
41#include <linux/random.h>
42#include <linux/percpu.h>
43#include <linux/smp.h>
44#include <linux/list.h>
45#include <linux/vmalloc.h>
46#include <linux/rtnetlink.h>
47#include <net/icmp.h>
48#include <net/ipv6.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020049#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#include <linux/ipv6.h>
51#include <linux/icmpv6.h>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080052#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54struct ipcomp6_tfms {
55 struct list_head list;
Herbert Xue4d5b792006-08-26 18:12:40 +100056 struct crypto_comp **tfms;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 int users;
58};
59
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080060static DEFINE_MUTEX(ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061static void **ipcomp6_scratches;
62static int ipcomp6_scratch_users;
63static LIST_HEAD(ipcomp6_tfms_list);
64
Herbert Xue6956332006-04-01 00:52:46 -080065static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066{
Herbert Xu364c6ba2006-06-09 16:10:40 -070067 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 struct ipv6hdr *iph;
Herbert Xu31a4ab92006-05-27 23:06:13 -070069 struct ipv6_comp_hdr *ipch;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 int plen, dlen;
71 struct ipcomp_data *ipcd = x->data;
72 u8 *start, *scratch;
Herbert Xue4d5b792006-08-26 18:12:40 +100073 struct crypto_comp *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 int cpu;
75
Herbert Xu364c6ba2006-06-09 16:10:40 -070076 if (skb_linearize_cow(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79 skb->ip_summed = CHECKSUM_NONE;
80
81 /* Remove ipcomp header and decompress original payload */
82 iph = skb->nh.ipv6h;
Herbert Xu31a4ab92006-05-27 23:06:13 -070083 ipch = (void *)skb->data;
84 skb->h.raw = skb->nh.raw + sizeof(*ipch);
85 __skb_pull(skb, sizeof(*ipch));
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87 /* decompression */
88 plen = skb->len;
89 dlen = IPCOMP_SCRATCH_SIZE;
90 start = skb->data;
91
92 cpu = get_cpu();
93 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
94 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
95
96 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
97 if (err) {
98 err = -EINVAL;
99 goto out_put_cpu;
100 }
101
102 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
103 err = -EINVAL;
104 goto out_put_cpu;
105 }
106
107 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
108 if (err) {
109 goto out_put_cpu;
110 }
111
Herbert Xuda952312006-07-11 13:50:09 -0700112 skb->truesize += dlen - plen;
113 __skb_put(skb, dlen - plen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 memcpy(skb->data, scratch, dlen);
Herbert Xu31a4ab92006-05-27 23:06:13 -0700115 err = ipch->nexthdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117out_put_cpu:
118 put_cpu();
119out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 return err;
121}
122
123static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
124{
125 int err;
126 struct ipv6hdr *top_iph;
127 int hdr_len;
128 struct ipv6_comp_hdr *ipch;
129 struct ipcomp_data *ipcd = x->data;
130 int plen, dlen;
131 u8 *start, *scratch;
Herbert Xue4d5b792006-08-26 18:12:40 +1000132 struct crypto_comp *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 int cpu;
134
135 hdr_len = skb->h.raw - skb->data;
136
137 /* check whether datagram len is larger than threshold */
138 if ((skb->len - hdr_len) < ipcd->threshold) {
139 goto out_ok;
140 }
141
Herbert Xu364c6ba2006-06-09 16:10:40 -0700142 if (skb_linearize_cow(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 goto out_ok;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145 /* compression */
146 plen = skb->len - hdr_len;
147 dlen = IPCOMP_SCRATCH_SIZE;
148 start = skb->h.raw;
149
150 cpu = get_cpu();
151 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
152 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
153
154 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
155 if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
156 put_cpu();
157 goto out_ok;
158 }
159 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
160 put_cpu();
161 pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
162
163 /* insert ipcomp header and replace datagram */
164 top_iph = (struct ipv6hdr *)skb->data;
165
166 top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
167
168 ipch = (struct ipv6_comp_hdr *)start;
169 ipch->nexthdr = *skb->nh.raw;
170 ipch->flags = 0;
171 ipch->cpi = htons((u16 )ntohl(x->id.spi));
172 *skb->nh.raw = IPPROTO_COMP;
173
174out_ok:
175 return 0;
176}
177
178static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
179 int type, int code, int offset, __u32 info)
180{
Al Viroa94cfd12006-09-27 18:47:24 -0700181 __be32 spi;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
183 struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
184 struct xfrm_state *x;
185
186 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
187 return;
188
Alexey Dobriyan4195f812006-05-22 16:53:22 -0700189 spi = htonl(ntohs(ipcomph->cpi));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
191 if (!x)
192 return;
193
Joe Perches46b86a22006-01-13 14:29:07 -0800194 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 spi, NIP6(iph->daddr));
196 xfrm_state_put(x);
197}
198
199static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
200{
201 struct xfrm_state *t = NULL;
202
203 t = xfrm_state_alloc();
204 if (!t)
205 goto out;
206
207 t->id.proto = IPPROTO_IPV6;
208 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
Herbert Xu6abaaaa2006-03-26 17:37:54 -0800209 if (!t->id.spi)
210 goto error;
211
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
213 memcpy(&t->sel, &x->sel, sizeof(t->sel));
214 t->props.family = AF_INET6;
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700215 t->props.mode = XFRM_MODE_TUNNEL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
217
Herbert Xu72cb6962005-06-20 13:18:08 -0700218 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 goto error;
220
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 atomic_set(&t->tunnel_users, 1);
222
223out:
224 return t;
225
226error:
Herbert Xu6abaaaa2006-03-26 17:37:54 -0800227 t->km.state = XFRM_STATE_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 xfrm_state_put(t);
Herbert Xu6abaaaa2006-03-26 17:37:54 -0800229 t = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 goto out;
231}
232
233static int ipcomp6_tunnel_attach(struct xfrm_state *x)
234{
235 int err = 0;
236 struct xfrm_state *t = NULL;
Al Viroa94cfd12006-09-27 18:47:24 -0700237 __be32 spi;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
239 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
240 if (spi)
241 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
242 spi, IPPROTO_IPV6, AF_INET6);
243 if (!t) {
244 t = ipcomp6_tunnel_create(x);
245 if (!t) {
246 err = -EINVAL;
247 goto out;
248 }
249 xfrm_state_insert(t);
250 xfrm_state_hold(t);
251 }
252 x->tunnel = t;
253 atomic_inc(&t->tunnel_users);
254
255out:
256 return err;
257}
258
259static void ipcomp6_free_scratches(void)
260{
261 int i;
262 void **scratches;
263
264 if (--ipcomp6_scratch_users)
265 return;
266
267 scratches = ipcomp6_scratches;
268 if (!scratches)
269 return;
270
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700271 for_each_possible_cpu(i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 void *scratch = *per_cpu_ptr(scratches, i);
Jesper Juhl2b191be2006-03-20 17:46:29 -0800273
274 vfree(scratch);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 }
276
277 free_percpu(scratches);
278}
279
280static void **ipcomp6_alloc_scratches(void)
281{
282 int i;
283 void **scratches;
284
285 if (ipcomp6_scratch_users++)
286 return ipcomp6_scratches;
287
288 scratches = alloc_percpu(void *);
289 if (!scratches)
290 return NULL;
291
292 ipcomp6_scratches = scratches;
293
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700294 for_each_possible_cpu(i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
296 if (!scratch)
297 return NULL;
298 *per_cpu_ptr(scratches, i) = scratch;
299 }
300
301 return scratches;
302}
303
Herbert Xue4d5b792006-08-26 18:12:40 +1000304static void ipcomp6_free_tfms(struct crypto_comp **tfms)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305{
306 struct ipcomp6_tfms *pos;
307 int cpu;
308
309 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
310 if (pos->tfms == tfms)
311 break;
312 }
313
314 BUG_TRAP(pos);
315
316 if (--pos->users)
317 return;
318
319 list_del(&pos->list);
320 kfree(pos);
321
322 if (!tfms)
323 return;
324
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700325 for_each_possible_cpu(cpu) {
Herbert Xue4d5b792006-08-26 18:12:40 +1000326 struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
327 crypto_free_comp(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 }
329 free_percpu(tfms);
330}
331
Herbert Xue4d5b792006-08-26 18:12:40 +1000332static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333{
334 struct ipcomp6_tfms *pos;
Herbert Xue4d5b792006-08-26 18:12:40 +1000335 struct crypto_comp **tfms;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 int cpu;
337
338 /* This can be any valid CPU ID so we don't need locking. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700339 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
341 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
Herbert Xue4d5b792006-08-26 18:12:40 +1000342 struct crypto_comp *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
344 tfms = pos->tfms;
345 tfm = *per_cpu_ptr(tfms, cpu);
346
Herbert Xue4d5b792006-08-26 18:12:40 +1000347 if (!strcmp(crypto_comp_name(tfm), alg_name)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 pos->users++;
349 return tfms;
350 }
351 }
352
353 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
354 if (!pos)
355 return NULL;
356
357 pos->users = 1;
358 INIT_LIST_HEAD(&pos->list);
359 list_add(&pos->list, &ipcomp6_tfms_list);
360
Herbert Xue4d5b792006-08-26 18:12:40 +1000361 pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 if (!tfms)
363 goto error;
364
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700365 for_each_possible_cpu(cpu) {
Herbert Xue4d5b792006-08-26 18:12:40 +1000366 struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
367 CRYPTO_ALG_ASYNC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 if (!tfm)
369 goto error;
370 *per_cpu_ptr(tfms, cpu) = tfm;
371 }
372
373 return tfms;
374
375error:
376 ipcomp6_free_tfms(tfms);
377 return NULL;
378}
379
380static void ipcomp6_free_data(struct ipcomp_data *ipcd)
381{
382 if (ipcd->tfms)
383 ipcomp6_free_tfms(ipcd->tfms);
384 ipcomp6_free_scratches();
385}
386
387static void ipcomp6_destroy(struct xfrm_state *x)
388{
389 struct ipcomp_data *ipcd = x->data;
390 if (!ipcd)
391 return;
392 xfrm_state_delete_tunnel(x);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800393 mutex_lock(&ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 ipcomp6_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800395 mutex_unlock(&ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 kfree(ipcd);
397
398 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
399}
400
Herbert Xu72cb6962005-06-20 13:18:08 -0700401static int ipcomp6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402{
403 int err;
404 struct ipcomp_data *ipcd;
405 struct xfrm_algo_desc *calg_desc;
406
407 err = -EINVAL;
408 if (!x->calg)
409 goto out;
410
411 if (x->encap)
412 goto out;
413
414 err = -ENOMEM;
Ingo Oeser0c600ed2006-03-20 23:01:32 -0800415 ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 if (!ipcd)
417 goto out;
418
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 x->props.header_len = 0;
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700420 if (x->props.mode == XFRM_MODE_TUNNEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 x->props.header_len += sizeof(struct ipv6hdr);
422
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800423 mutex_lock(&ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 if (!ipcomp6_alloc_scratches())
425 goto error;
426
427 ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
428 if (!ipcd->tfms)
429 goto error;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800430 mutex_unlock(&ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700432 if (x->props.mode == XFRM_MODE_TUNNEL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 err = ipcomp6_tunnel_attach(x);
434 if (err)
435 goto error_tunnel;
436 }
437
438 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
439 BUG_ON(!calg_desc);
440 ipcd->threshold = calg_desc->uinfo.comp.threshold;
441 x->data = ipcd;
442 err = 0;
443out:
444 return err;
445error_tunnel:
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800446 mutex_lock(&ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447error:
448 ipcomp6_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800449 mutex_unlock(&ipcomp6_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 kfree(ipcd);
451
452 goto out;
453}
454
455static struct xfrm_type ipcomp6_type =
456{
457 .description = "IPCOMP6",
458 .owner = THIS_MODULE,
459 .proto = IPPROTO_COMP,
460 .init_state = ipcomp6_init_state,
461 .destructor = ipcomp6_destroy,
462 .input = ipcomp6_input,
463 .output = ipcomp6_output,
Masahide NAKAMURAaee5adb2006-08-23 17:57:28 -0700464 .hdr_offset = xfrm6_find_1stfragopt,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465};
466
467static struct inet6_protocol ipcomp6_protocol =
468{
469 .handler = xfrm6_rcv,
470 .err_handler = ipcomp6_err,
471 .flags = INET6_PROTO_NOPOLICY,
472};
473
474static int __init ipcomp6_init(void)
475{
476 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
477 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
478 return -EAGAIN;
479 }
480 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
481 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
482 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
483 return -EAGAIN;
484 }
485 return 0;
486}
487
488static void __exit ipcomp6_fini(void)
489{
490 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
491 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
492 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
493 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
494}
495
496module_init(ipcomp6_init);
497module_exit(ipcomp6_fini);
498MODULE_LICENSE("GPL");
499MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
500MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
501
502