blob: d511a884dad07504fb73aeb5bf134086aff3c152 [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 */
33#include <linux/config.h>
34#include <linux/module.h>
35#include <net/ip.h>
36#include <net/xfrm.h>
37#include <net/ipcomp.h>
38#include <asm/scatterlist.h>
39#include <asm/semaphore.h>
40#include <linux/crypto.h>
41#include <linux/pfkeyv2.h>
42#include <linux/random.h>
43#include <linux/percpu.h>
44#include <linux/smp.h>
45#include <linux/list.h>
46#include <linux/vmalloc.h>
47#include <linux/rtnetlink.h>
48#include <net/icmp.h>
49#include <net/ipv6.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020050#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051#include <linux/ipv6.h>
52#include <linux/icmpv6.h>
53
54struct ipcomp6_tfms {
55 struct list_head list;
56 struct crypto_tfm **tfms;
57 int users;
58};
59
60static DECLARE_MUTEX(ipcomp6_resource_sem);
61static void **ipcomp6_scratches;
62static int ipcomp6_scratch_users;
63static LIST_HEAD(ipcomp6_tfms_list);
64
65static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
66{
67 int err = 0;
68 u8 nexthdr = 0;
69 int hdr_len = skb->h.raw - skb->nh.raw;
70 unsigned char *tmp_hdr = NULL;
71 struct ipv6hdr *iph;
72 int plen, dlen;
73 struct ipcomp_data *ipcd = x->data;
74 u8 *start, *scratch;
75 struct crypto_tfm *tfm;
76 int cpu;
77
78 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
79 skb_linearize(skb, GFP_ATOMIC) != 0) {
80 err = -ENOMEM;
81 goto out;
82 }
83
84 skb->ip_summed = CHECKSUM_NONE;
85
86 /* Remove ipcomp header and decompress original payload */
87 iph = skb->nh.ipv6h;
88 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
89 if (!tmp_hdr)
90 goto out;
91 memcpy(tmp_hdr, iph, hdr_len);
92 nexthdr = *(u8 *)skb->data;
93 skb_pull(skb, sizeof(struct ipv6_comp_hdr));
94 skb->nh.raw += sizeof(struct ipv6_comp_hdr);
95 memcpy(skb->nh.raw, tmp_hdr, hdr_len);
96 iph = skb->nh.ipv6h;
97 iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
98 skb->h.raw = skb->data;
99
100 /* decompression */
101 plen = skb->len;
102 dlen = IPCOMP_SCRATCH_SIZE;
103 start = skb->data;
104
105 cpu = get_cpu();
106 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
107 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
108
109 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
110 if (err) {
111 err = -EINVAL;
112 goto out_put_cpu;
113 }
114
115 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
116 err = -EINVAL;
117 goto out_put_cpu;
118 }
119
120 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
121 if (err) {
122 goto out_put_cpu;
123 }
124
125 skb_put(skb, dlen - plen);
126 memcpy(skb->data, scratch, dlen);
127
128 iph = skb->nh.ipv6h;
129 iph->payload_len = htons(skb->len);
130
131out_put_cpu:
132 put_cpu();
133out:
Jesper Juhla51482b2005-11-08 09:41:34 -0800134 kfree(tmp_hdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 if (err)
136 goto error_out;
137 return nexthdr;
138error_out:
139 return err;
140}
141
142static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
143{
144 int err;
145 struct ipv6hdr *top_iph;
146 int hdr_len;
147 struct ipv6_comp_hdr *ipch;
148 struct ipcomp_data *ipcd = x->data;
149 int plen, dlen;
150 u8 *start, *scratch;
151 struct crypto_tfm *tfm;
152 int cpu;
153
154 hdr_len = skb->h.raw - skb->data;
155
156 /* check whether datagram len is larger than threshold */
157 if ((skb->len - hdr_len) < ipcd->threshold) {
158 goto out_ok;
159 }
160
161 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
162 skb_linearize(skb, GFP_ATOMIC) != 0) {
163 goto out_ok;
164 }
165
166 /* compression */
167 plen = skb->len - hdr_len;
168 dlen = IPCOMP_SCRATCH_SIZE;
169 start = skb->h.raw;
170
171 cpu = get_cpu();
172 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
173 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
174
175 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
176 if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
177 put_cpu();
178 goto out_ok;
179 }
180 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
181 put_cpu();
182 pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
183
184 /* insert ipcomp header and replace datagram */
185 top_iph = (struct ipv6hdr *)skb->data;
186
187 top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
188
189 ipch = (struct ipv6_comp_hdr *)start;
190 ipch->nexthdr = *skb->nh.raw;
191 ipch->flags = 0;
192 ipch->cpi = htons((u16 )ntohl(x->id.spi));
193 *skb->nh.raw = IPPROTO_COMP;
194
195out_ok:
196 return 0;
197}
198
199static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
200 int type, int code, int offset, __u32 info)
201{
202 u32 spi;
203 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
204 struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
205 struct xfrm_state *x;
206
207 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
208 return;
209
210 spi = ntohl(ntohs(ipcomph->cpi));
211 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
212 if (!x)
213 return;
214
Joe Perches46b86a22006-01-13 14:29:07 -0800215 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 spi, NIP6(iph->daddr));
217 xfrm_state_put(x);
218}
219
220static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
221{
222 struct xfrm_state *t = NULL;
223
224 t = xfrm_state_alloc();
225 if (!t)
226 goto out;
227
228 t->id.proto = IPPROTO_IPV6;
229 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
230 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
231 memcpy(&t->sel, &x->sel, sizeof(t->sel));
232 t->props.family = AF_INET6;
233 t->props.mode = 1;
234 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
235
Herbert Xu72cb6962005-06-20 13:18:08 -0700236 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 goto error;
238
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 atomic_set(&t->tunnel_users, 1);
240
241out:
242 return t;
243
244error:
245 xfrm_state_put(t);
246 goto out;
247}
248
249static int ipcomp6_tunnel_attach(struct xfrm_state *x)
250{
251 int err = 0;
252 struct xfrm_state *t = NULL;
253 u32 spi;
254
255 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
256 if (spi)
257 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
258 spi, IPPROTO_IPV6, AF_INET6);
259 if (!t) {
260 t = ipcomp6_tunnel_create(x);
261 if (!t) {
262 err = -EINVAL;
263 goto out;
264 }
265 xfrm_state_insert(t);
266 xfrm_state_hold(t);
267 }
268 x->tunnel = t;
269 atomic_inc(&t->tunnel_users);
270
271out:
272 return err;
273}
274
275static void ipcomp6_free_scratches(void)
276{
277 int i;
278 void **scratches;
279
280 if (--ipcomp6_scratch_users)
281 return;
282
283 scratches = ipcomp6_scratches;
284 if (!scratches)
285 return;
286
287 for_each_cpu(i) {
288 void *scratch = *per_cpu_ptr(scratches, i);
289 if (scratch)
290 vfree(scratch);
291 }
292
293 free_percpu(scratches);
294}
295
296static void **ipcomp6_alloc_scratches(void)
297{
298 int i;
299 void **scratches;
300
301 if (ipcomp6_scratch_users++)
302 return ipcomp6_scratches;
303
304 scratches = alloc_percpu(void *);
305 if (!scratches)
306 return NULL;
307
308 ipcomp6_scratches = scratches;
309
310 for_each_cpu(i) {
311 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
312 if (!scratch)
313 return NULL;
314 *per_cpu_ptr(scratches, i) = scratch;
315 }
316
317 return scratches;
318}
319
320static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
321{
322 struct ipcomp6_tfms *pos;
323 int cpu;
324
325 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
326 if (pos->tfms == tfms)
327 break;
328 }
329
330 BUG_TRAP(pos);
331
332 if (--pos->users)
333 return;
334
335 list_del(&pos->list);
336 kfree(pos);
337
338 if (!tfms)
339 return;
340
341 for_each_cpu(cpu) {
342 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700343 crypto_free_tfm(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 }
345 free_percpu(tfms);
346}
347
348static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
349{
350 struct ipcomp6_tfms *pos;
351 struct crypto_tfm **tfms;
352 int cpu;
353
354 /* This can be any valid CPU ID so we don't need locking. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700355 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
357 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
358 struct crypto_tfm *tfm;
359
360 tfms = pos->tfms;
361 tfm = *per_cpu_ptr(tfms, cpu);
362
363 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
364 pos->users++;
365 return tfms;
366 }
367 }
368
369 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
370 if (!pos)
371 return NULL;
372
373 pos->users = 1;
374 INIT_LIST_HEAD(&pos->list);
375 list_add(&pos->list, &ipcomp6_tfms_list);
376
377 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
378 if (!tfms)
379 goto error;
380
381 for_each_cpu(cpu) {
382 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
383 if (!tfm)
384 goto error;
385 *per_cpu_ptr(tfms, cpu) = tfm;
386 }
387
388 return tfms;
389
390error:
391 ipcomp6_free_tfms(tfms);
392 return NULL;
393}
394
395static void ipcomp6_free_data(struct ipcomp_data *ipcd)
396{
397 if (ipcd->tfms)
398 ipcomp6_free_tfms(ipcd->tfms);
399 ipcomp6_free_scratches();
400}
401
402static void ipcomp6_destroy(struct xfrm_state *x)
403{
404 struct ipcomp_data *ipcd = x->data;
405 if (!ipcd)
406 return;
407 xfrm_state_delete_tunnel(x);
408 down(&ipcomp6_resource_sem);
409 ipcomp6_free_data(ipcd);
410 up(&ipcomp6_resource_sem);
411 kfree(ipcd);
412
413 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
414}
415
Herbert Xu72cb6962005-06-20 13:18:08 -0700416static int ipcomp6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417{
418 int err;
419 struct ipcomp_data *ipcd;
420 struct xfrm_algo_desc *calg_desc;
421
422 err = -EINVAL;
423 if (!x->calg)
424 goto out;
425
426 if (x->encap)
427 goto out;
428
429 err = -ENOMEM;
430 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
431 if (!ipcd)
432 goto out;
433
434 memset(ipcd, 0, sizeof(*ipcd));
435 x->props.header_len = 0;
436 if (x->props.mode)
437 x->props.header_len += sizeof(struct ipv6hdr);
438
439 down(&ipcomp6_resource_sem);
440 if (!ipcomp6_alloc_scratches())
441 goto error;
442
443 ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
444 if (!ipcd->tfms)
445 goto error;
446 up(&ipcomp6_resource_sem);
447
448 if (x->props.mode) {
449 err = ipcomp6_tunnel_attach(x);
450 if (err)
451 goto error_tunnel;
452 }
453
454 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
455 BUG_ON(!calg_desc);
456 ipcd->threshold = calg_desc->uinfo.comp.threshold;
457 x->data = ipcd;
458 err = 0;
459out:
460 return err;
461error_tunnel:
462 down(&ipcomp6_resource_sem);
463error:
464 ipcomp6_free_data(ipcd);
465 up(&ipcomp6_resource_sem);
466 kfree(ipcd);
467
468 goto out;
469}
470
471static struct xfrm_type ipcomp6_type =
472{
473 .description = "IPCOMP6",
474 .owner = THIS_MODULE,
475 .proto = IPPROTO_COMP,
476 .init_state = ipcomp6_init_state,
477 .destructor = ipcomp6_destroy,
478 .input = ipcomp6_input,
479 .output = ipcomp6_output,
480};
481
482static struct inet6_protocol ipcomp6_protocol =
483{
484 .handler = xfrm6_rcv,
485 .err_handler = ipcomp6_err,
486 .flags = INET6_PROTO_NOPOLICY,
487};
488
489static int __init ipcomp6_init(void)
490{
491 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
492 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
493 return -EAGAIN;
494 }
495 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
496 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
497 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
498 return -EAGAIN;
499 }
500 return 0;
501}
502
503static void __exit ipcomp6_fini(void)
504{
505 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
506 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
507 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
508 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
509}
510
511module_init(ipcomp6_init);
512module_exit(ipcomp6_fini);
513MODULE_LICENSE("GPL");
514MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
515MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
516
517