blob: c95020f7c81e38a2bdb0672fc7ecf5660c2f78d6 [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
84static int ipcomp_input(struct xfrm_state *x,
85 struct xfrm_decap_state *decap, struct sk_buff *skb)
86{
87 u8 nexthdr;
88 int err = 0;
89 struct iphdr *iph;
90 union {
91 struct iphdr iph;
92 char buf[60];
93 } tmp_iph;
94
95
96 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
97 skb_linearize(skb, GFP_ATOMIC) != 0) {
98 err = -ENOMEM;
99 goto out;
100 }
101
102 skb->ip_summed = CHECKSUM_NONE;
103
104 /* Remove ipcomp header and decompress original payload */
105 iph = skb->nh.iph;
106 memcpy(&tmp_iph, iph, iph->ihl * 4);
107 nexthdr = *(u8 *)skb->data;
108 skb_pull(skb, sizeof(struct ip_comp_hdr));
109 skb->nh.raw += sizeof(struct ip_comp_hdr);
110 memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
111 iph = skb->nh.iph;
112 iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr));
113 iph->protocol = nexthdr;
114 skb->h.raw = skb->data;
115 err = ipcomp_decompress(x, skb);
116
117out:
118 return err;
119}
120
121static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
122{
123 int err, plen, dlen, ihlen;
124 struct iphdr *iph = skb->nh.iph;
125 struct ipcomp_data *ipcd = x->data;
126 u8 *start, *scratch;
127 struct crypto_tfm *tfm;
128 int cpu;
129
130 ihlen = iph->ihl * 4;
131 plen = skb->len - ihlen;
132 dlen = IPCOMP_SCRATCH_SIZE;
133 start = skb->data + ihlen;
134
135 cpu = get_cpu();
136 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
137 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
138
139 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
140 if (err)
141 goto out;
142
143 if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
144 err = -EMSGSIZE;
145 goto out;
146 }
147
148 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
149 put_cpu();
150
151 pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
152 return 0;
153
154out:
155 put_cpu();
156 return err;
157}
158
159static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
160{
161 int err;
162 struct iphdr *iph;
163 struct ip_comp_hdr *ipch;
164 struct ipcomp_data *ipcd = x->data;
165 int hdr_len = 0;
166
167 iph = skb->nh.iph;
168 iph->tot_len = htons(skb->len);
169 hdr_len = iph->ihl * 4;
170 if ((skb->len - hdr_len) < ipcd->threshold) {
171 /* Don't bother compressing */
172 goto out_ok;
173 }
174
175 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
176 skb_linearize(skb, GFP_ATOMIC) != 0) {
177 goto out_ok;
178 }
179
180 err = ipcomp_compress(x, skb);
181 iph = skb->nh.iph;
182
183 if (err) {
184 goto out_ok;
185 }
186
187 /* Install ipcomp header, convert into ipcomp datagram. */
188 iph->tot_len = htons(skb->len);
189 ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
190 ipch->nexthdr = iph->protocol;
191 ipch->flags = 0;
192 ipch->cpi = htons((u16 )ntohl(x->id.spi));
193 iph->protocol = IPPROTO_COMP;
194 ip_send_check(iph);
195 return 0;
196
197out_ok:
198 if (x->props.mode)
199 ip_send_check(iph);
200 return 0;
201}
202
203static void ipcomp4_err(struct sk_buff *skb, u32 info)
204{
205 u32 spi;
206 struct iphdr *iph = (struct iphdr *)skb->data;
207 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
208 struct xfrm_state *x;
209
210 if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
211 skb->h.icmph->code != ICMP_FRAG_NEEDED)
212 return;
213
214 spi = ntohl(ntohs(ipch->cpi));
215 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
216 spi, IPPROTO_COMP, AF_INET);
217 if (!x)
218 return;
Patrick McHardy64ce2072005-08-09 20:50:53 -0700219 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
220 spi, NIPQUAD(iph->daddr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 xfrm_state_put(x);
222}
223
224/* We always hold one tunnel user reference to indicate a tunnel */
225static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
226{
227 struct xfrm_state *t;
228
229 t = xfrm_state_alloc();
230 if (t == NULL)
231 goto out;
232
233 t->id.proto = IPPROTO_IPIP;
234 t->id.spi = x->props.saddr.a4;
235 t->id.daddr.a4 = x->id.daddr.a4;
236 memcpy(&t->sel, &x->sel, sizeof(t->sel));
237 t->props.family = AF_INET;
238 t->props.mode = 1;
239 t->props.saddr.a4 = x->props.saddr.a4;
240 t->props.flags = x->props.flags;
Herbert Xu72cb6962005-06-20 13:18:08 -0700241
242 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 goto error;
244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 atomic_set(&t->tunnel_users, 1);
246out:
247 return t;
248
249error:
250 t->km.state = XFRM_STATE_DEAD;
251 xfrm_state_put(t);
252 t = NULL;
253 goto out;
254}
255
256/*
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800257 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 * always incremented on success.
259 */
260static int ipcomp_tunnel_attach(struct xfrm_state *x)
261{
262 int err = 0;
263 struct xfrm_state *t;
264
265 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
266 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
267 if (!t) {
268 t = ipcomp_tunnel_create(x);
269 if (!t) {
270 err = -EINVAL;
271 goto out;
272 }
273 xfrm_state_insert(t);
274 xfrm_state_hold(t);
275 }
276 x->tunnel = t;
277 atomic_inc(&t->tunnel_users);
278out:
279 return err;
280}
281
282static void ipcomp_free_scratches(void)
283{
284 int i;
285 void **scratches;
286
287 if (--ipcomp_scratch_users)
288 return;
289
290 scratches = ipcomp_scratches;
291 if (!scratches)
292 return;
293
294 for_each_cpu(i) {
295 void *scratch = *per_cpu_ptr(scratches, i);
296 if (scratch)
297 vfree(scratch);
298 }
299
300 free_percpu(scratches);
301}
302
303static void **ipcomp_alloc_scratches(void)
304{
305 int i;
306 void **scratches;
307
308 if (ipcomp_scratch_users++)
309 return ipcomp_scratches;
310
311 scratches = alloc_percpu(void *);
312 if (!scratches)
313 return NULL;
314
315 ipcomp_scratches = scratches;
316
317 for_each_cpu(i) {
318 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
319 if (!scratch)
320 return NULL;
321 *per_cpu_ptr(scratches, i) = scratch;
322 }
323
324 return scratches;
325}
326
327static void ipcomp_free_tfms(struct crypto_tfm **tfms)
328{
329 struct ipcomp_tfms *pos;
330 int cpu;
331
332 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
333 if (pos->tfms == tfms)
334 break;
335 }
336
337 BUG_TRAP(pos);
338
339 if (--pos->users)
340 return;
341
342 list_del(&pos->list);
343 kfree(pos);
344
345 if (!tfms)
346 return;
347
348 for_each_cpu(cpu) {
349 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700350 crypto_free_tfm(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 }
352 free_percpu(tfms);
353}
354
355static struct crypto_tfm **ipcomp_alloc_tfms(const char *alg_name)
356{
357 struct ipcomp_tfms *pos;
358 struct crypto_tfm **tfms;
359 int cpu;
360
361 /* This can be any valid CPU ID so we don't need locking. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700362 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
364 list_for_each_entry(pos, &ipcomp_tfms_list, list) {
365 struct crypto_tfm *tfm;
366
367 tfms = pos->tfms;
368 tfm = *per_cpu_ptr(tfms, cpu);
369
370 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
371 pos->users++;
372 return tfms;
373 }
374 }
375
376 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
377 if (!pos)
378 return NULL;
379
380 pos->users = 1;
381 INIT_LIST_HEAD(&pos->list);
382 list_add(&pos->list, &ipcomp_tfms_list);
383
384 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
385 if (!tfms)
386 goto error;
387
388 for_each_cpu(cpu) {
389 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
390 if (!tfm)
391 goto error;
392 *per_cpu_ptr(tfms, cpu) = tfm;
393 }
394
395 return tfms;
396
397error:
398 ipcomp_free_tfms(tfms);
399 return NULL;
400}
401
402static void ipcomp_free_data(struct ipcomp_data *ipcd)
403{
404 if (ipcd->tfms)
405 ipcomp_free_tfms(ipcd->tfms);
406 ipcomp_free_scratches();
407}
408
409static void ipcomp_destroy(struct xfrm_state *x)
410{
411 struct ipcomp_data *ipcd = x->data;
412 if (!ipcd)
413 return;
414 xfrm_state_delete_tunnel(x);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800415 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 ipcomp_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800417 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 kfree(ipcd);
419}
420
Herbert Xu72cb6962005-06-20 13:18:08 -0700421static int ipcomp_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422{
423 int err;
424 struct ipcomp_data *ipcd;
425 struct xfrm_algo_desc *calg_desc;
426
427 err = -EINVAL;
428 if (!x->calg)
429 goto out;
430
431 if (x->encap)
432 goto out;
433
434 err = -ENOMEM;
435 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
436 if (!ipcd)
437 goto out;
438
439 memset(ipcd, 0, sizeof(*ipcd));
440 x->props.header_len = 0;
441 if (x->props.mode)
442 x->props.header_len += sizeof(struct iphdr);
443
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800444 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 if (!ipcomp_alloc_scratches())
446 goto error;
447
448 ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
449 if (!ipcd->tfms)
450 goto error;
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800451 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
453 if (x->props.mode) {
454 err = ipcomp_tunnel_attach(x);
455 if (err)
456 goto error_tunnel;
457 }
458
459 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
460 BUG_ON(!calg_desc);
461 ipcd->threshold = calg_desc->uinfo.comp.threshold;
462 x->data = ipcd;
463 err = 0;
464out:
465 return err;
466
467error_tunnel:
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800468 mutex_lock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469error:
470 ipcomp_free_data(ipcd);
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -0800471 mutex_unlock(&ipcomp_resource_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 kfree(ipcd);
473 goto out;
474}
475
476static struct xfrm_type ipcomp_type = {
477 .description = "IPCOMP4",
478 .owner = THIS_MODULE,
479 .proto = IPPROTO_COMP,
480 .init_state = ipcomp_init_state,
481 .destructor = ipcomp_destroy,
482 .input = ipcomp_input,
483 .output = ipcomp_output
484};
485
486static struct net_protocol ipcomp4_protocol = {
487 .handler = xfrm4_rcv,
488 .err_handler = ipcomp4_err,
489 .no_policy = 1,
490};
491
492static int __init ipcomp4_init(void)
493{
494 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
495 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
496 return -EAGAIN;
497 }
498 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
499 printk(KERN_INFO "ipcomp init: can't add protocol\n");
500 xfrm_unregister_type(&ipcomp_type, AF_INET);
501 return -EAGAIN;
502 }
503 return 0;
504}
505
506static void __exit ipcomp4_fini(void)
507{
508 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
509 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
510 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
511 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
512}
513
514module_init(ipcomp4_init);
515module_exit(ipcomp4_fini);
516
517MODULE_LICENSE("GPL");
518MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
519MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
520