blob: 95278b22b669ab895903fe039fa3e7d2e1f56a25 [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 */
16#include <linux/config.h>
17#include <linux/module.h>
18#include <asm/scatterlist.h>
19#include <asm/semaphore.h>
20#include <linux/crypto.h>
21#include <linux/pfkeyv2.h>
22#include <linux/percpu.h>
23#include <linux/smp.h>
24#include <linux/list.h>
25#include <linux/vmalloc.h>
26#include <linux/rtnetlink.h>
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080027#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <net/ip.h>
29#include <net/xfrm.h>
30#include <net/icmp.h>
31#include <net/ipcomp.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020032#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34struct ipcomp_tfms {
35 struct list_head list;
36 struct crypto_tfm **tfms;
37 int users;
38};
39
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080040static DEFINE_MUTEX(ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041static void **ipcomp_scratches;
42static int ipcomp_scratch_users;
43static LIST_HEAD(ipcomp_tfms_list);
44
45static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
46{
47 int err, plen, dlen;
48 struct iphdr *iph;
49 struct ipcomp_data *ipcd = x->data;
50 u8 *start, *scratch;
51 struct crypto_tfm *tfm;
52 int cpu;
53
54 plen = skb->len;
55 dlen = IPCOMP_SCRATCH_SIZE;
56 start = skb->data;
57
58 cpu = get_cpu();
59 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
60 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
61
62 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
63 if (err)
64 goto out;
65
66 if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
67 err = -EINVAL;
68 goto out;
69 }
70
71 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
72 if (err)
73 goto out;
74
75 skb_put(skb, dlen - plen);
76 memcpy(skb->data, scratch, dlen);
77 iph = skb->nh.iph;
78 iph->tot_len = htons(dlen + iph->ihl * 4);
79out:
80 put_cpu();
81 return err;
82}
83
Herbert Xue6956332006-04-01 00:52:46 -080084static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070085{
86 u8 nexthdr;
87 int err = 0;
88 struct iphdr *iph;
89 union {
90 struct iphdr iph;
91 char buf[60];
92 } tmp_iph;
93
94
95 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
96 skb_linearize(skb, GFP_ATOMIC) != 0) {
97 err = -ENOMEM;
98 goto out;
99 }
100
101 skb->ip_summed = CHECKSUM_NONE;
102
103 /* Remove ipcomp header and decompress original payload */
104 iph = skb->nh.iph;
105 memcpy(&tmp_iph, iph, iph->ihl * 4);
106 nexthdr = *(u8 *)skb->data;
107 skb_pull(skb, sizeof(struct ip_comp_hdr));
108 skb->nh.raw += sizeof(struct ip_comp_hdr);
109 memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
110 iph = skb->nh.iph;
111 iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr));
112 iph->protocol = nexthdr;
113 skb->h.raw = skb->data;
114 err = ipcomp_decompress(x, skb);
115
116out:
117 return err;
118}
119
120static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
121{
122 int err, plen, dlen, ihlen;
123 struct iphdr *iph = skb->nh.iph;
124 struct ipcomp_data *ipcd = x->data;
125 u8 *start, *scratch;
126 struct crypto_tfm *tfm;
127 int cpu;
128
129 ihlen = iph->ihl * 4;
130 plen = skb->len - ihlen;
131 dlen = IPCOMP_SCRATCH_SIZE;
132 start = skb->data + ihlen;
133
134 cpu = get_cpu();
135 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
136 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
137
138 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
139 if (err)
140 goto out;
141
142 if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
143 err = -EMSGSIZE;
144 goto out;
145 }
146
147 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
148 put_cpu();
149
150 pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
151 return 0;
152
153out:
154 put_cpu();
155 return err;
156}
157
158static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
159{
160 int err;
161 struct iphdr *iph;
162 struct ip_comp_hdr *ipch;
163 struct ipcomp_data *ipcd = x->data;
164 int hdr_len = 0;
165
166 iph = skb->nh.iph;
167 iph->tot_len = htons(skb->len);
168 hdr_len = iph->ihl * 4;
169 if ((skb->len - hdr_len) < ipcd->threshold) {
170 /* Don't bother compressing */
171 goto out_ok;
172 }
173
174 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
175 skb_linearize(skb, GFP_ATOMIC) != 0) {
176 goto out_ok;
177 }
178
179 err = ipcomp_compress(x, skb);
180 iph = skb->nh.iph;
181
182 if (err) {
183 goto out_ok;
184 }
185
186 /* Install ipcomp header, convert into ipcomp datagram. */
187 iph->tot_len = htons(skb->len);
188 ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
189 ipch->nexthdr = iph->protocol;
190 ipch->flags = 0;
191 ipch->cpi = htons((u16 )ntohl(x->id.spi));
192 iph->protocol = IPPROTO_COMP;
193 ip_send_check(iph);
194 return 0;
195
196out_ok:
197 if (x->props.mode)
198 ip_send_check(iph);
199 return 0;
200}
201
202static void ipcomp4_err(struct sk_buff *skb, u32 info)
203{
204 u32 spi;
205 struct iphdr *iph = (struct iphdr *)skb->data;
206 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
207 struct xfrm_state *x;
208
209 if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
210 skb->h.icmph->code != ICMP_FRAG_NEEDED)
211 return;
212
Alexey Dobriyan4195f812006-05-22 16:53:22 -0700213 spi = htonl(ntohs(ipch->cpi));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
215 spi, IPPROTO_COMP, AF_INET);
216 if (!x)
217 return;
Patrick McHardy64ce2072005-08-09 20:50:53 -0700218 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
219 spi, NIPQUAD(iph->daddr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 xfrm_state_put(x);
221}
222
223/* We always hold one tunnel user reference to indicate a tunnel */
224static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
225{
226 struct xfrm_state *t;
227
228 t = xfrm_state_alloc();
229 if (t == NULL)
230 goto out;
231
232 t->id.proto = IPPROTO_IPIP;
233 t->id.spi = x->props.saddr.a4;
234 t->id.daddr.a4 = x->id.daddr.a4;
235 memcpy(&t->sel, &x->sel, sizeof(t->sel));
236 t->props.family = AF_INET;
237 t->props.mode = 1;
238 t->props.saddr.a4 = x->props.saddr.a4;
239 t->props.flags = x->props.flags;
Herbert Xu72cb6962005-06-20 13:18:08 -0700240
241 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 goto error;
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 atomic_set(&t->tunnel_users, 1);
245out:
246 return t;
247
248error:
249 t->km.state = XFRM_STATE_DEAD;
250 xfrm_state_put(t);
251 t = NULL;
252 goto out;
253}
254
255/*
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800256 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 * always incremented on success.
258 */
259static int ipcomp_tunnel_attach(struct xfrm_state *x)
260{
261 int err = 0;
262 struct xfrm_state *t;
263
264 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
265 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
266 if (!t) {
267 t = ipcomp_tunnel_create(x);
268 if (!t) {
269 err = -EINVAL;
270 goto out;
271 }
272 xfrm_state_insert(t);
273 xfrm_state_hold(t);
274 }
275 x->tunnel = t;
276 atomic_inc(&t->tunnel_users);
277out:
278 return err;
279}
280
281static void ipcomp_free_scratches(void)
282{
283 int i;
284 void **scratches;
285
286 if (--ipcomp_scratch_users)
287 return;
288
289 scratches = ipcomp_scratches;
290 if (!scratches)
291 return;
292
Jesper Juhl63903ca2006-04-18 14:51:44 -0700293 for_each_possible_cpu(i)
294 vfree(*per_cpu_ptr(scratches, i));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
296 free_percpu(scratches);
297}
298
299static void **ipcomp_alloc_scratches(void)
300{
301 int i;
302 void **scratches;
303
304 if (ipcomp_scratch_users++)
305 return ipcomp_scratches;
306
307 scratches = alloc_percpu(void *);
308 if (!scratches)
309 return NULL;
310
311 ipcomp_scratches = scratches;
312
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700313 for_each_possible_cpu(i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
315 if (!scratch)
316 return NULL;
317 *per_cpu_ptr(scratches, i) = scratch;
318 }
319
320 return scratches;
321}
322
323static void ipcomp_free_tfms(struct crypto_tfm **tfms)
324{
325 struct ipcomp_tfms *pos;
326 int cpu;
327
328 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
329 if (pos->tfms == tfms)
330 break;
331 }
332
333 BUG_TRAP(pos);
334
335 if (--pos->users)
336 return;
337
338 list_del(&pos->list);
339 kfree(pos);
340
341 if (!tfms)
342 return;
343
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700344 for_each_possible_cpu(cpu) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700346 crypto_free_tfm(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 }
348 free_percpu(tfms);
349}
350
351static struct crypto_tfm **ipcomp_alloc_tfms(const char *alg_name)
352{
353 struct ipcomp_tfms *pos;
354 struct crypto_tfm **tfms;
355 int cpu;
356
357 /* This can be any valid CPU ID so we don't need locking. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700358 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
360 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
361 struct crypto_tfm *tfm;
362
363 tfms = pos->tfms;
364 tfm = *per_cpu_ptr(tfms, cpu);
365
366 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
367 pos->users++;
368 return tfms;
369 }
370 }
371
372 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
373 if (!pos)
374 return NULL;
375
376 pos->users = 1;
377 INIT_LIST_HEAD(&pos->list);
378 list_add(&pos->list, &ipcomp_tfms_list);
379
380 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
381 if (!tfms)
382 goto error;
383
KAMEZAWA Hiroyuki6f912042006-04-10 22:52:50 -0700384 for_each_possible_cpu(cpu) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
386 if (!tfm)
387 goto error;
388 *per_cpu_ptr(tfms, cpu) = tfm;
389 }
390
391 return tfms;
392
393error:
394 ipcomp_free_tfms(tfms);
395 return NULL;
396}
397
398static void ipcomp_free_data(struct ipcomp_data *ipcd)
399{
400 if (ipcd->tfms)
401 ipcomp_free_tfms(ipcd->tfms);
402 ipcomp_free_scratches();
403}
404
405static void ipcomp_destroy(struct xfrm_state *x)
406{
407 struct ipcomp_data *ipcd = x->data;
408 if (!ipcd)
409 return;
410 xfrm_state_delete_tunnel(x);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800411 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 ipcomp_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800413 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 kfree(ipcd);
415}
416
Herbert Xu72cb6962005-06-20 13:18:08 -0700417static int ipcomp_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418{
419 int err;
420 struct ipcomp_data *ipcd;
421 struct xfrm_algo_desc *calg_desc;
422
423 err = -EINVAL;
424 if (!x->calg)
425 goto out;
426
427 if (x->encap)
428 goto out;
429
430 err = -ENOMEM;
431 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
432 if (!ipcd)
433 goto out;
434
435 memset(ipcd, 0, sizeof(*ipcd));
436 x->props.header_len = 0;
437 if (x->props.mode)
438 x->props.header_len += sizeof(struct iphdr);
439
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800440 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 if (!ipcomp_alloc_scratches())
442 goto error;
443
444 ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
445 if (!ipcd->tfms)
446 goto error;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800447 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448
449 if (x->props.mode) {
450 err = ipcomp_tunnel_attach(x);
451 if (err)
452 goto error_tunnel;
453 }
454
455 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
456 BUG_ON(!calg_desc);
457 ipcd->threshold = calg_desc->uinfo.comp.threshold;
458 x->data = ipcd;
459 err = 0;
460out:
461 return err;
462
463error_tunnel:
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800464 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465error:
466 ipcomp_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800467 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 kfree(ipcd);
469 goto out;
470}
471
472static struct xfrm_type ipcomp_type = {
473 .description = "IPCOMP4",
474 .owner = THIS_MODULE,
475 .proto = IPPROTO_COMP,
476 .init_state = ipcomp_init_state,
477 .destructor = ipcomp_destroy,
478 .input = ipcomp_input,
479 .output = ipcomp_output
480};
481
482static struct net_protocol ipcomp4_protocol = {
483 .handler = xfrm4_rcv,
484 .err_handler = ipcomp4_err,
485 .no_policy = 1,
486};
487
488static int __init ipcomp4_init(void)
489{
490 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
491 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
492 return -EAGAIN;
493 }
494 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
495 printk(KERN_INFO "ipcomp init: can't add protocol\n");
496 xfrm_unregister_type(&ipcomp_type, AF_INET);
497 return -EAGAIN;
498 }
499 return 0;
500}
501
502static void __exit ipcomp4_fini(void)
503{
504 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
505 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
506 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
507 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
508}
509
510module_init(ipcomp4_init);
511module_exit(ipcomp4_fini);
512
513MODULE_LICENSE("GPL");
514MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
515MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
516