blob: 2017d36024d48d61816bd52e82bf67f4c196479d [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IP Payload Compression Protocol (IPComp) - RFC3173.
3 *
4 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 * Todo:
12 * - Tunable compression parameters.
13 * - Compression stats.
14 * - Adaptive compression.
15 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/module.h>
17#include <asm/scatterlist.h>
18#include <asm/semaphore.h>
19#include <linux/crypto.h>
20#include <linux/pfkeyv2.h>
21#include <linux/percpu.h>
22#include <linux/smp.h>
23#include <linux/list.h>
24#include <linux/vmalloc.h>
25#include <linux/rtnetlink.h>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080026#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <net/ip.h>
28#include <net/xfrm.h>
29#include <net/icmp.h>
30#include <net/ipcomp.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020031#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33struct ipcomp_tfms {
34 struct list_head list;
Herbert Xue4d5b792006-08-26 18:12:40 +100035 struct crypto_comp **tfms;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 int users;
37};
38
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080039static DEFINE_MUTEX(ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040static void **ipcomp_scratches;
41static int ipcomp_scratch_users;
42static LIST_HEAD(ipcomp_tfms_list);
43
44static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
45{
46 int err, plen, dlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 struct ipcomp_data *ipcd = x->data;
48 u8 *start, *scratch;
Herbert Xue4d5b792006-08-26 18:12:40 +100049 struct crypto_comp *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 int cpu;
51
52 plen = skb->len;
53 dlen = IPCOMP_SCRATCH_SIZE;
54 start = skb->data;
55
56 cpu = get_cpu();
57 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
58 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
59
60 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
61 if (err)
62 goto out;
63
64 if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
65 err = -EINVAL;
66 goto out;
67 }
68
69 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
70 if (err)
71 goto out;
72
Herbert Xuda952312006-07-11 13:50:09 -070073 skb->truesize += dlen - plen;
74 __skb_put(skb, dlen - plen);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 memcpy(skb->data, scratch, dlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076out:
77 put_cpu();
78 return err;
79}
80
Herbert Xue6956332006-04-01 00:52:46 -080081static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070082{
Herbert Xu364c6ba2006-06-09 16:10:40 -070083 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 struct iphdr *iph;
Herbert Xu31a4ab92006-05-27 23:06:13 -070085 struct ip_comp_hdr *ipch;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Herbert Xu364c6ba2006-06-09 16:10:40 -070087 if (skb_linearize_cow(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
90 skb->ip_summed = CHECKSUM_NONE;
91
92 /* Remove ipcomp header and decompress original payload */
93 iph = skb->nh.iph;
Herbert Xu31a4ab92006-05-27 23:06:13 -070094 ipch = (void *)skb->data;
95 iph->protocol = ipch->nexthdr;
96 skb->h.raw = skb->nh.raw + sizeof(*ipch);
97 __skb_pull(skb, sizeof(*ipch));
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 err = ipcomp_decompress(x, skb);
99
100out:
101 return err;
102}
103
104static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
105{
106 int err, plen, dlen, ihlen;
107 struct iphdr *iph = skb->nh.iph;
108 struct ipcomp_data *ipcd = x->data;
109 u8 *start, *scratch;
Herbert Xue4d5b792006-08-26 18:12:40 +1000110 struct crypto_comp *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 int cpu;
112
113 ihlen = iph->ihl * 4;
114 plen = skb->len - ihlen;
115 dlen = IPCOMP_SCRATCH_SIZE;
116 start = skb->data + ihlen;
117
118 cpu = get_cpu();
119 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
120 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
121
122 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
123 if (err)
124 goto out;
125
126 if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
127 err = -EMSGSIZE;
128 goto out;
129 }
130
131 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
132 put_cpu();
133
134 pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
135 return 0;
136
137out:
138 put_cpu();
139 return err;
140}
141
142static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
143{
144 int err;
145 struct iphdr *iph;
146 struct ip_comp_hdr *ipch;
147 struct ipcomp_data *ipcd = x->data;
148 int hdr_len = 0;
149
150 iph = skb->nh.iph;
151 iph->tot_len = htons(skb->len);
152 hdr_len = iph->ihl * 4;
153 if ((skb->len - hdr_len) < ipcd->threshold) {
154 /* Don't bother compressing */
155 goto out_ok;
156 }
157
Herbert Xu364c6ba2006-06-09 16:10:40 -0700158 if (skb_linearize_cow(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 goto out_ok;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160
161 err = ipcomp_compress(x, skb);
162 iph = skb->nh.iph;
163
164 if (err) {
165 goto out_ok;
166 }
167
168 /* Install ipcomp header, convert into ipcomp datagram. */
169 iph->tot_len = htons(skb->len);
170 ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
171 ipch->nexthdr = iph->protocol;
172 ipch->flags = 0;
173 ipch->cpi = htons((u16 )ntohl(x->id.spi));
174 iph->protocol = IPPROTO_COMP;
175 ip_send_check(iph);
176 return 0;
177
178out_ok:
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700179 if (x->props.mode == XFRM_MODE_TUNNEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 ip_send_check(iph);
181 return 0;
182}
183
184static void ipcomp4_err(struct sk_buff *skb, u32 info)
185{
Al Viroa94cfd12006-09-27 18:47:24 -0700186 __be32 spi;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 struct iphdr *iph = (struct iphdr *)skb->data;
188 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
189 struct xfrm_state *x;
190
191 if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
192 skb->h.icmph->code != ICMP_FRAG_NEEDED)
193 return;
194
Alexey Dobriyan4195f812006-05-22 16:53:22 -0700195 spi = htonl(ntohs(ipch->cpi));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
197 spi, IPPROTO_COMP, AF_INET);
198 if (!x)
199 return;
Patrick McHardy64ce2072005-08-09 20:50:53 -0700200 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
201 spi, NIPQUAD(iph->daddr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 xfrm_state_put(x);
203}
204
205/* We always hold one tunnel user reference to indicate a tunnel */
206static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
207{
208 struct xfrm_state *t;
209
210 t = xfrm_state_alloc();
211 if (t == NULL)
212 goto out;
213
214 t->id.proto = IPPROTO_IPIP;
215 t->id.spi = x->props.saddr.a4;
216 t->id.daddr.a4 = x->id.daddr.a4;
217 memcpy(&t->sel, &x->sel, sizeof(t->sel));
218 t->props.family = AF_INET;
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700219 t->props.mode = XFRM_MODE_TUNNEL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 t->props.saddr.a4 = x->props.saddr.a4;
221 t->props.flags = x->props.flags;
Herbert Xu72cb6962005-06-20 13:18:08 -0700222
223 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 goto error;
225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 atomic_set(&t->tunnel_users, 1);
227out:
228 return t;
229
230error:
231 t->km.state = XFRM_STATE_DEAD;
232 xfrm_state_put(t);
233 t = NULL;
234 goto out;
235}
236
237/*
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800238 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 * always incremented on success.
240 */
241static int ipcomp_tunnel_attach(struct xfrm_state *x)
242{
243 int err = 0;
244 struct xfrm_state *t;
245
246 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
247 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
248 if (!t) {
249 t = ipcomp_tunnel_create(x);
250 if (!t) {
251 err = -EINVAL;
252 goto out;
253 }
254 xfrm_state_insert(t);
255 xfrm_state_hold(t);
256 }
257 x->tunnel = t;
258 atomic_inc(&t->tunnel_users);
259out:
260 return err;
261}
262
263static void ipcomp_free_scratches(void)
264{
265 int i;
266 void **scratches;
267
268 if (--ipcomp_scratch_users)
269 return;
270
271 scratches = ipcomp_scratches;
272 if (!scratches)
273 return;
274
Jesper Juhl63903ca2006-04-18 14:51:44 -0700275 for_each_possible_cpu(i)
276 vfree(*per_cpu_ptr(scratches, i));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
278 free_percpu(scratches);
279}
280
281static void **ipcomp_alloc_scratches(void)
282{
283 int i;
284 void **scratches;
285
286 if (ipcomp_scratch_users++)
287 return ipcomp_scratches;
288
289 scratches = alloc_percpu(void *);
290 if (!scratches)
291 return NULL;
292
293 ipcomp_scratches = scratches;
294
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700295 for_each_possible_cpu(i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
297 if (!scratch)
298 return NULL;
299 *per_cpu_ptr(scratches, i) = scratch;
300 }
301
302 return scratches;
303}
304
Herbert Xue4d5b792006-08-26 18:12:40 +1000305static void ipcomp_free_tfms(struct crypto_comp **tfms)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306{
307 struct ipcomp_tfms *pos;
308 int cpu;
309
310 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
311 if (pos->tfms == tfms)
312 break;
313 }
314
315 BUG_TRAP(pos);
316
317 if (--pos->users)
318 return;
319
320 list_del(&pos->list);
321 kfree(pos);
322
323 if (!tfms)
324 return;
325
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700326 for_each_possible_cpu(cpu) {
Herbert Xue4d5b792006-08-26 18:12:40 +1000327 struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
328 crypto_free_comp(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 }
330 free_percpu(tfms);
331}
332
Herbert Xue4d5b792006-08-26 18:12:40 +1000333static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334{
335 struct ipcomp_tfms *pos;
Herbert Xue4d5b792006-08-26 18:12:40 +1000336 struct crypto_comp **tfms;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 int cpu;
338
339 /* This can be any valid CPU ID so we don't need locking. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700340 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341
342 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
Herbert Xue4d5b792006-08-26 18:12:40 +1000343 struct crypto_comp *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
345 tfms = pos->tfms;
346 tfm = *per_cpu_ptr(tfms, cpu);
347
Herbert Xue4d5b792006-08-26 18:12:40 +1000348 if (!strcmp(crypto_comp_name(tfm), alg_name)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 pos->users++;
350 return tfms;
351 }
352 }
353
354 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
355 if (!pos)
356 return NULL;
357
358 pos->users = 1;
359 INIT_LIST_HEAD(&pos->list);
360 list_add(&pos->list, &ipcomp_tfms_list);
361
Herbert Xue4d5b792006-08-26 18:12:40 +1000362 pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 if (!tfms)
364 goto error;
365
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700366 for_each_possible_cpu(cpu) {
Herbert Xue4d5b792006-08-26 18:12:40 +1000367 struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
368 CRYPTO_ALG_ASYNC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (!tfm)
370 goto error;
371 *per_cpu_ptr(tfms, cpu) = tfm;
372 }
373
374 return tfms;
375
376error:
377 ipcomp_free_tfms(tfms);
378 return NULL;
379}
380
381static void ipcomp_free_data(struct ipcomp_data *ipcd)
382{
383 if (ipcd->tfms)
384 ipcomp_free_tfms(ipcd->tfms);
385 ipcomp_free_scratches();
386}
387
388static void ipcomp_destroy(struct xfrm_state *x)
389{
390 struct ipcomp_data *ipcd = x->data;
391 if (!ipcd)
392 return;
393 xfrm_state_delete_tunnel(x);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800394 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 ipcomp_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800396 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 kfree(ipcd);
398}
399
Herbert Xu72cb6962005-06-20 13:18:08 -0700400static int ipcomp_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401{
402 int err;
403 struct ipcomp_data *ipcd;
404 struct xfrm_algo_desc *calg_desc;
405
406 err = -EINVAL;
407 if (!x->calg)
408 goto out;
409
410 if (x->encap)
411 goto out;
412
413 err = -ENOMEM;
Panagiotis Issaris0da974f2006-07-21 14:51:30 -0700414 ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 if (!ipcd)
416 goto out;
417
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 x->props.header_len = 0;
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700419 if (x->props.mode == XFRM_MODE_TUNNEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 x->props.header_len += sizeof(struct iphdr);
421
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800422 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 if (!ipcomp_alloc_scratches())
424 goto error;
425
426 ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
427 if (!ipcd->tfms)
428 goto error;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800429 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700431 if (x->props.mode == XFRM_MODE_TUNNEL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 err = ipcomp_tunnel_attach(x);
433 if (err)
434 goto error_tunnel;
435 }
436
437 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
438 BUG_ON(!calg_desc);
439 ipcd->threshold = calg_desc->uinfo.comp.threshold;
440 x->data = ipcd;
441 err = 0;
442out:
443 return err;
444
445error_tunnel:
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800446 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447error:
448 ipcomp_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800449 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 kfree(ipcd);
451 goto out;
452}
453
454static struct xfrm_type ipcomp_type = {
455 .description = "IPCOMP4",
456 .owner = THIS_MODULE,
457 .proto = IPPROTO_COMP,
458 .init_state = ipcomp_init_state,
459 .destructor = ipcomp_destroy,
460 .input = ipcomp_input,
461 .output = ipcomp_output
462};
463
464static struct net_protocol ipcomp4_protocol = {
465 .handler = xfrm4_rcv,
466 .err_handler = ipcomp4_err,
467 .no_policy = 1,
468};
469
470static int __init ipcomp4_init(void)
471{
472 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
473 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
474 return -EAGAIN;
475 }
476 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
477 printk(KERN_INFO "ipcomp init: can't add protocol\n");
478 xfrm_unregister_type(&ipcomp_type, AF_INET);
479 return -EAGAIN;
480 }
481 return 0;
482}
483
484static void __exit ipcomp4_fini(void)
485{
486 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
487 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
488 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
489 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
490}
491
492module_init(ipcomp4_init);
493module_exit(ipcomp4_fini);
494
495MODULE_LICENSE("GPL");
496MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
497MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
498