blob: 135383ef538f5a33573d745d17962237af3ae082 [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>
50#include <linux/ipv6.h>
51#include <linux/icmpv6.h>
52
53struct ipcomp6_tfms {
54 struct list_head list;
55 struct crypto_tfm **tfms;
56 int users;
57};
58
59static DECLARE_MUTEX(ipcomp6_resource_sem);
60static void **ipcomp6_scratches;
61static int ipcomp6_scratch_users;
62static LIST_HEAD(ipcomp6_tfms_list);
63
64static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
65{
66 int err = 0;
67 u8 nexthdr = 0;
68 int hdr_len = skb->h.raw - skb->nh.raw;
69 unsigned char *tmp_hdr = NULL;
70 struct ipv6hdr *iph;
71 int plen, dlen;
72 struct ipcomp_data *ipcd = x->data;
73 u8 *start, *scratch;
74 struct crypto_tfm *tfm;
75 int cpu;
76
77 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
78 skb_linearize(skb, GFP_ATOMIC) != 0) {
79 err = -ENOMEM;
80 goto out;
81 }
82
83 skb->ip_summed = CHECKSUM_NONE;
84
85 /* Remove ipcomp header and decompress original payload */
86 iph = skb->nh.ipv6h;
87 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
88 if (!tmp_hdr)
89 goto out;
90 memcpy(tmp_hdr, iph, hdr_len);
91 nexthdr = *(u8 *)skb->data;
92 skb_pull(skb, sizeof(struct ipv6_comp_hdr));
93 skb->nh.raw += sizeof(struct ipv6_comp_hdr);
94 memcpy(skb->nh.raw, tmp_hdr, hdr_len);
95 iph = skb->nh.ipv6h;
96 iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
97 skb->h.raw = skb->data;
98
99 /* decompression */
100 plen = skb->len;
101 dlen = IPCOMP_SCRATCH_SIZE;
102 start = skb->data;
103
104 cpu = get_cpu();
105 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
106 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
107
108 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
109 if (err) {
110 err = -EINVAL;
111 goto out_put_cpu;
112 }
113
114 if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
115 err = -EINVAL;
116 goto out_put_cpu;
117 }
118
119 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
120 if (err) {
121 goto out_put_cpu;
122 }
123
124 skb_put(skb, dlen - plen);
125 memcpy(skb->data, scratch, dlen);
126
127 iph = skb->nh.ipv6h;
128 iph->payload_len = htons(skb->len);
129
130out_put_cpu:
131 put_cpu();
132out:
133 if (tmp_hdr)
134 kfree(tmp_hdr);
135 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
215 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/"
216 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
217 spi, NIP6(iph->daddr));
218 xfrm_state_put(x);
219}
220
221static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
222{
223 struct xfrm_state *t = NULL;
224
225 t = xfrm_state_alloc();
226 if (!t)
227 goto out;
228
229 t->id.proto = IPPROTO_IPV6;
230 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
231 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
232 memcpy(&t->sel, &x->sel, sizeof(t->sel));
233 t->props.family = AF_INET6;
234 t->props.mode = 1;
235 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
236
Herbert Xu72cb6962005-06-20 13:18:08 -0700237 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 goto error;
239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 atomic_set(&t->tunnel_users, 1);
241
242out:
243 return t;
244
245error:
246 xfrm_state_put(t);
247 goto out;
248}
249
250static int ipcomp6_tunnel_attach(struct xfrm_state *x)
251{
252 int err = 0;
253 struct xfrm_state *t = NULL;
254 u32 spi;
255
256 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
257 if (spi)
258 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
259 spi, IPPROTO_IPV6, AF_INET6);
260 if (!t) {
261 t = ipcomp6_tunnel_create(x);
262 if (!t) {
263 err = -EINVAL;
264 goto out;
265 }
266 xfrm_state_insert(t);
267 xfrm_state_hold(t);
268 }
269 x->tunnel = t;
270 atomic_inc(&t->tunnel_users);
271
272out:
273 return err;
274}
275
276static void ipcomp6_free_scratches(void)
277{
278 int i;
279 void **scratches;
280
281 if (--ipcomp6_scratch_users)
282 return;
283
284 scratches = ipcomp6_scratches;
285 if (!scratches)
286 return;
287
288 for_each_cpu(i) {
289 void *scratch = *per_cpu_ptr(scratches, i);
290 if (scratch)
291 vfree(scratch);
292 }
293
294 free_percpu(scratches);
295}
296
297static void **ipcomp6_alloc_scratches(void)
298{
299 int i;
300 void **scratches;
301
302 if (ipcomp6_scratch_users++)
303 return ipcomp6_scratches;
304
305 scratches = alloc_percpu(void *);
306 if (!scratches)
307 return NULL;
308
309 ipcomp6_scratches = scratches;
310
311 for_each_cpu(i) {
312 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
313 if (!scratch)
314 return NULL;
315 *per_cpu_ptr(scratches, i) = scratch;
316 }
317
318 return scratches;
319}
320
321static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
322{
323 struct ipcomp6_tfms *pos;
324 int cpu;
325
326 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
327 if (pos->tfms == tfms)
328 break;
329 }
330
331 BUG_TRAP(pos);
332
333 if (--pos->users)
334 return;
335
336 list_del(&pos->list);
337 kfree(pos);
338
339 if (!tfms)
340 return;
341
342 for_each_cpu(cpu) {
343 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
344 if (tfm)
345 crypto_free_tfm(tfm);
346 }
347 free_percpu(tfms);
348}
349
350static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
351{
352 struct ipcomp6_tfms *pos;
353 struct crypto_tfm **tfms;
354 int cpu;
355
356 /* This can be any valid CPU ID so we don't need locking. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700357 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358
359 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
360 struct crypto_tfm *tfm;
361
362 tfms = pos->tfms;
363 tfm = *per_cpu_ptr(tfms, cpu);
364
365 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
366 pos->users++;
367 return tfms;
368 }
369 }
370
371 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
372 if (!pos)
373 return NULL;
374
375 pos->users = 1;
376 INIT_LIST_HEAD(&pos->list);
377 list_add(&pos->list, &ipcomp6_tfms_list);
378
379 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
380 if (!tfms)
381 goto error;
382
383 for_each_cpu(cpu) {
384 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
385 if (!tfm)
386 goto error;
387 *per_cpu_ptr(tfms, cpu) = tfm;
388 }
389
390 return tfms;
391
392error:
393 ipcomp6_free_tfms(tfms);
394 return NULL;
395}
396
397static void ipcomp6_free_data(struct ipcomp_data *ipcd)
398{
399 if (ipcd->tfms)
400 ipcomp6_free_tfms(ipcd->tfms);
401 ipcomp6_free_scratches();
402}
403
404static void ipcomp6_destroy(struct xfrm_state *x)
405{
406 struct ipcomp_data *ipcd = x->data;
407 if (!ipcd)
408 return;
409 xfrm_state_delete_tunnel(x);
410 down(&ipcomp6_resource_sem);
411 ipcomp6_free_data(ipcd);
412 up(&ipcomp6_resource_sem);
413 kfree(ipcd);
414
415 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
416}
417
Herbert Xu72cb6962005-06-20 13:18:08 -0700418static int ipcomp6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419{
420 int err;
421 struct ipcomp_data *ipcd;
422 struct xfrm_algo_desc *calg_desc;
423
424 err = -EINVAL;
425 if (!x->calg)
426 goto out;
427
428 if (x->encap)
429 goto out;
430
431 err = -ENOMEM;
432 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
433 if (!ipcd)
434 goto out;
435
436 memset(ipcd, 0, sizeof(*ipcd));
437 x->props.header_len = 0;
438 if (x->props.mode)
439 x->props.header_len += sizeof(struct ipv6hdr);
440
441 down(&ipcomp6_resource_sem);
442 if (!ipcomp6_alloc_scratches())
443 goto error;
444
445 ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
446 if (!ipcd->tfms)
447 goto error;
448 up(&ipcomp6_resource_sem);
449
450 if (x->props.mode) {
451 err = ipcomp6_tunnel_attach(x);
452 if (err)
453 goto error_tunnel;
454 }
455
456 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
457 BUG_ON(!calg_desc);
458 ipcd->threshold = calg_desc->uinfo.comp.threshold;
459 x->data = ipcd;
460 err = 0;
461out:
462 return err;
463error_tunnel:
464 down(&ipcomp6_resource_sem);
465error:
466 ipcomp6_free_data(ipcd);
467 up(&ipcomp6_resource_sem);
468 kfree(ipcd);
469
470 goto out;
471}
472
473static struct xfrm_type ipcomp6_type =
474{
475 .description = "IPCOMP6",
476 .owner = THIS_MODULE,
477 .proto = IPPROTO_COMP,
478 .init_state = ipcomp6_init_state,
479 .destructor = ipcomp6_destroy,
480 .input = ipcomp6_input,
481 .output = ipcomp6_output,
482};
483
484static struct inet6_protocol ipcomp6_protocol =
485{
486 .handler = xfrm6_rcv,
487 .err_handler = ipcomp6_err,
488 .flags = INET6_PROTO_NOPOLICY,
489};
490
491static int __init ipcomp6_init(void)
492{
493 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
494 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
495 return -EAGAIN;
496 }
497 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
498 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
499 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
500 return -EAGAIN;
501 }
502 return 0;
503}
504
505static void __exit ipcomp6_fini(void)
506{
507 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
508 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
509 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
510 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
511}
512
513module_init(ipcomp6_init);
514module_exit(ipcomp6_fini);
515MODULE_LICENSE("GPL");
516MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
517MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
518
519