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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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. | |
1ab1457c | 12 | * |
1da177e4 LT |
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. | |
1ab1457c | 17 | * |
1da177e4 LT |
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 | */ | |
1ab1457c | 22 | /* |
1da177e4 LT |
23 | * [Memo] |
24 | * | |
25 | * Outbound: | |
1ab1457c YH |
26 | * The compression of IP datagram MUST be done before AH/ESP processing, |
27 | * fragmentation, and the addition of Hop-by-Hop/Routing header. | |
1da177e4 LT |
28 | * |
29 | * Inbound: | |
1ab1457c | 30 | * The decompression of IP datagram MUST be done after the reassembly, |
1da177e4 LT |
31 | * AH/ESP processing. |
32 | */ | |
1da177e4 LT |
33 | #include <linux/module.h> |
34 | #include <net/ip.h> | |
35 | #include <net/xfrm.h> | |
36 | #include <net/ipcomp.h> | |
37 | #include <asm/scatterlist.h> | |
38 | #include <asm/semaphore.h> | |
39 | #include <linux/crypto.h> | |
40 | #include <linux/pfkeyv2.h> | |
41 | #include <linux/random.h> | |
42 | #include <linux/percpu.h> | |
43 | #include <linux/smp.h> | |
44 | #include <linux/list.h> | |
45 | #include <linux/vmalloc.h> | |
46 | #include <linux/rtnetlink.h> | |
47 | #include <net/icmp.h> | |
48 | #include <net/ipv6.h> | |
14c85021 | 49 | #include <net/protocol.h> |
1da177e4 LT |
50 | #include <linux/ipv6.h> |
51 | #include <linux/icmpv6.h> | |
4a3e2f71 | 52 | #include <linux/mutex.h> |
1da177e4 LT |
53 | |
54 | struct ipcomp6_tfms { | |
55 | struct list_head list; | |
e4d5b79c | 56 | struct crypto_comp **tfms; |
1da177e4 LT |
57 | int users; |
58 | }; | |
59 | ||
4a3e2f71 | 60 | static DEFINE_MUTEX(ipcomp6_resource_mutex); |
1da177e4 LT |
61 | static void **ipcomp6_scratches; |
62 | static int ipcomp6_scratch_users; | |
63 | static LIST_HEAD(ipcomp6_tfms_list); | |
64 | ||
e695633e | 65 | static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 | 66 | { |
364c6bad | 67 | int err = -ENOMEM; |
31a4ab93 | 68 | struct ipv6_comp_hdr *ipch; |
1da177e4 LT |
69 | int plen, dlen; |
70 | struct ipcomp_data *ipcd = x->data; | |
71 | u8 *start, *scratch; | |
e4d5b79c | 72 | struct crypto_comp *tfm; |
1da177e4 LT |
73 | int cpu; |
74 | ||
364c6bad | 75 | if (skb_linearize_cow(skb)) |
1da177e4 | 76 | goto out; |
1da177e4 LT |
77 | |
78 | skb->ip_summed = CHECKSUM_NONE; | |
79 | ||
80 | /* Remove ipcomp header and decompress original payload */ | |
31a4ab93 | 81 | ipch = (void *)skb->data; |
b0e380b1 | 82 | skb->transport_header = skb->network_header + sizeof(*ipch); |
31a4ab93 | 83 | __skb_pull(skb, sizeof(*ipch)); |
1da177e4 LT |
84 | |
85 | /* decompression */ | |
86 | plen = skb->len; | |
87 | dlen = IPCOMP_SCRATCH_SIZE; | |
88 | start = skb->data; | |
89 | ||
90 | cpu = get_cpu(); | |
91 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
92 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
93 | ||
94 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
95 | if (err) { | |
96 | err = -EINVAL; | |
97 | goto out_put_cpu; | |
98 | } | |
99 | ||
100 | if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) { | |
101 | err = -EINVAL; | |
102 | goto out_put_cpu; | |
103 | } | |
104 | ||
105 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
106 | if (err) { | |
107 | goto out_put_cpu; | |
108 | } | |
109 | ||
da952315 HX |
110 | skb->truesize += dlen - plen; |
111 | __skb_put(skb, dlen - plen); | |
27d7ff46 | 112 | skb_copy_to_linear_data(skb, scratch, dlen); |
31a4ab93 | 113 | err = ipch->nexthdr; |
1da177e4 | 114 | |
1da177e4 LT |
115 | out_put_cpu: |
116 | put_cpu(); | |
117 | out: | |
1da177e4 LT |
118 | return err; |
119 | } | |
120 | ||
121 | static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb) | |
122 | { | |
123 | int err; | |
124 | struct ipv6hdr *top_iph; | |
1da177e4 LT |
125 | struct ipv6_comp_hdr *ipch; |
126 | struct ipcomp_data *ipcd = x->data; | |
127 | int plen, dlen; | |
128 | u8 *start, *scratch; | |
e4d5b79c | 129 | struct crypto_comp *tfm; |
1da177e4 | 130 | int cpu; |
ea2ae17d | 131 | int hdr_len = skb_transport_offset(skb); |
1da177e4 LT |
132 | |
133 | /* check whether datagram len is larger than threshold */ | |
134 | if ((skb->len - hdr_len) < ipcd->threshold) { | |
135 | goto out_ok; | |
136 | } | |
137 | ||
364c6bad | 138 | if (skb_linearize_cow(skb)) |
1da177e4 | 139 | goto out_ok; |
1da177e4 LT |
140 | |
141 | /* compression */ | |
142 | plen = skb->len - hdr_len; | |
143 | dlen = IPCOMP_SCRATCH_SIZE; | |
9c70220b | 144 | start = skb_transport_header(skb); |
1da177e4 LT |
145 | |
146 | cpu = get_cpu(); | |
147 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
148 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
149 | ||
150 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
151 | if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) { | |
152 | put_cpu(); | |
153 | goto out_ok; | |
154 | } | |
155 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
156 | put_cpu(); | |
157 | pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr)); | |
158 | ||
159 | /* insert ipcomp header and replace datagram */ | |
160 | top_iph = (struct ipv6hdr *)skb->data; | |
161 | ||
162 | top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); | |
163 | ||
164 | ipch = (struct ipv6_comp_hdr *)start; | |
d56f90a7 | 165 | ipch->nexthdr = *skb_network_header(skb); |
1da177e4 LT |
166 | ipch->flags = 0; |
167 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
d56f90a7 | 168 | *skb_network_header(skb) = IPPROTO_COMP; |
1da177e4 LT |
169 | |
170 | out_ok: | |
171 | return 0; | |
172 | } | |
173 | ||
174 | static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
1ab1457c | 175 | int type, int code, int offset, __be32 info) |
1da177e4 | 176 | { |
a94cfd19 | 177 | __be32 spi; |
1da177e4 LT |
178 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; |
179 | struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset); | |
180 | struct xfrm_state *x; | |
181 | ||
182 | if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) | |
183 | return; | |
184 | ||
4195f814 | 185 | spi = htonl(ntohs(ipcomph->cpi)); |
1da177e4 LT |
186 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6); |
187 | if (!x) | |
188 | return; | |
189 | ||
46b86a2d | 190 | printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n", |
1da177e4 LT |
191 | spi, NIP6(iph->daddr)); |
192 | xfrm_state_put(x); | |
193 | } | |
194 | ||
195 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) | |
196 | { | |
197 | struct xfrm_state *t = NULL; | |
0a69452c | 198 | u8 mode = XFRM_MODE_TUNNEL; |
1da177e4 LT |
199 | |
200 | t = xfrm_state_alloc(); | |
201 | if (!t) | |
202 | goto out; | |
203 | ||
204 | t->id.proto = IPPROTO_IPV6; | |
205 | t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr); | |
6abaaaae HX |
206 | if (!t->id.spi) |
207 | goto error; | |
208 | ||
1da177e4 LT |
209 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); |
210 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
211 | t->props.family = AF_INET6; | |
0a69452c DB |
212 | if (x->props.mode == XFRM_MODE_BEET) |
213 | mode = x->props.mode; | |
214 | t->props.mode = mode; | |
1da177e4 LT |
215 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); |
216 | ||
72cb6962 | 217 | if (xfrm_init_state(t)) |
1da177e4 LT |
218 | goto error; |
219 | ||
1da177e4 LT |
220 | atomic_set(&t->tunnel_users, 1); |
221 | ||
222 | out: | |
223 | return t; | |
224 | ||
225 | error: | |
6abaaaae | 226 | t->km.state = XFRM_STATE_DEAD; |
1da177e4 | 227 | xfrm_state_put(t); |
6abaaaae | 228 | t = NULL; |
1da177e4 LT |
229 | goto out; |
230 | } | |
231 | ||
232 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) | |
233 | { | |
234 | int err = 0; | |
235 | struct xfrm_state *t = NULL; | |
a94cfd19 | 236 | __be32 spi; |
1da177e4 LT |
237 | |
238 | spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); | |
239 | if (spi) | |
240 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, | |
241 | spi, IPPROTO_IPV6, AF_INET6); | |
242 | if (!t) { | |
243 | t = ipcomp6_tunnel_create(x); | |
244 | if (!t) { | |
245 | err = -EINVAL; | |
246 | goto out; | |
247 | } | |
248 | xfrm_state_insert(t); | |
249 | xfrm_state_hold(t); | |
250 | } | |
251 | x->tunnel = t; | |
252 | atomic_inc(&t->tunnel_users); | |
253 | ||
254 | out: | |
255 | return err; | |
256 | } | |
257 | ||
258 | static void ipcomp6_free_scratches(void) | |
259 | { | |
260 | int i; | |
261 | void **scratches; | |
262 | ||
263 | if (--ipcomp6_scratch_users) | |
264 | return; | |
265 | ||
266 | scratches = ipcomp6_scratches; | |
267 | if (!scratches) | |
268 | return; | |
269 | ||
6f912042 | 270 | for_each_possible_cpu(i) { |
1da177e4 | 271 | void *scratch = *per_cpu_ptr(scratches, i); |
2b191bef JJ |
272 | |
273 | vfree(scratch); | |
1da177e4 LT |
274 | } |
275 | ||
276 | free_percpu(scratches); | |
277 | } | |
278 | ||
279 | static void **ipcomp6_alloc_scratches(void) | |
280 | { | |
281 | int i; | |
282 | void **scratches; | |
283 | ||
284 | if (ipcomp6_scratch_users++) | |
285 | return ipcomp6_scratches; | |
286 | ||
287 | scratches = alloc_percpu(void *); | |
288 | if (!scratches) | |
289 | return NULL; | |
290 | ||
291 | ipcomp6_scratches = scratches; | |
292 | ||
6f912042 | 293 | for_each_possible_cpu(i) { |
1da177e4 LT |
294 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
295 | if (!scratch) | |
296 | return NULL; | |
297 | *per_cpu_ptr(scratches, i) = scratch; | |
298 | } | |
299 | ||
300 | return scratches; | |
301 | } | |
302 | ||
e4d5b79c | 303 | static void ipcomp6_free_tfms(struct crypto_comp **tfms) |
1da177e4 LT |
304 | { |
305 | struct ipcomp6_tfms *pos; | |
306 | int cpu; | |
307 | ||
308 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
309 | if (pos->tfms == tfms) | |
310 | break; | |
311 | } | |
312 | ||
313 | BUG_TRAP(pos); | |
314 | ||
315 | if (--pos->users) | |
316 | return; | |
317 | ||
318 | list_del(&pos->list); | |
319 | kfree(pos); | |
320 | ||
321 | if (!tfms) | |
322 | return; | |
323 | ||
6f912042 | 324 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
325 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); |
326 | crypto_free_comp(tfm); | |
1da177e4 LT |
327 | } |
328 | free_percpu(tfms); | |
329 | } | |
330 | ||
e4d5b79c | 331 | static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name) |
1da177e4 LT |
332 | { |
333 | struct ipcomp6_tfms *pos; | |
e4d5b79c | 334 | struct crypto_comp **tfms; |
1da177e4 LT |
335 | int cpu; |
336 | ||
337 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 338 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
339 | |
340 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
e4d5b79c | 341 | struct crypto_comp *tfm; |
1da177e4 LT |
342 | |
343 | tfms = pos->tfms; | |
344 | tfm = *per_cpu_ptr(tfms, cpu); | |
345 | ||
e4d5b79c | 346 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { |
1da177e4 LT |
347 | pos->users++; |
348 | return tfms; | |
349 | } | |
350 | } | |
351 | ||
352 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
353 | if (!pos) | |
354 | return NULL; | |
355 | ||
356 | pos->users = 1; | |
357 | INIT_LIST_HEAD(&pos->list); | |
358 | list_add(&pos->list, &ipcomp6_tfms_list); | |
359 | ||
e4d5b79c | 360 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); |
1da177e4 LT |
361 | if (!tfms) |
362 | goto error; | |
363 | ||
6f912042 | 364 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
365 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0, |
366 | CRYPTO_ALG_ASYNC); | |
1da177e4 LT |
367 | if (!tfm) |
368 | goto error; | |
369 | *per_cpu_ptr(tfms, cpu) = tfm; | |
370 | } | |
371 | ||
372 | return tfms; | |
373 | ||
374 | error: | |
375 | ipcomp6_free_tfms(tfms); | |
376 | return NULL; | |
377 | } | |
378 | ||
379 | static void ipcomp6_free_data(struct ipcomp_data *ipcd) | |
380 | { | |
381 | if (ipcd->tfms) | |
382 | ipcomp6_free_tfms(ipcd->tfms); | |
383 | ipcomp6_free_scratches(); | |
384 | } | |
385 | ||
386 | static void ipcomp6_destroy(struct xfrm_state *x) | |
387 | { | |
388 | struct ipcomp_data *ipcd = x->data; | |
389 | if (!ipcd) | |
390 | return; | |
391 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 392 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 | 393 | ipcomp6_free_data(ipcd); |
4a3e2f71 | 394 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 LT |
395 | kfree(ipcd); |
396 | ||
397 | xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr); | |
398 | } | |
399 | ||
72cb6962 | 400 | static int ipcomp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
401 | { |
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; | |
0c600eda | 414 | ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL); |
1da177e4 LT |
415 | if (!ipcd) |
416 | goto out; | |
417 | ||
1da177e4 | 418 | x->props.header_len = 0; |
7e49e6de | 419 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 | 420 | x->props.header_len += sizeof(struct ipv6hdr); |
1ab1457c | 421 | |
4a3e2f71 | 422 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 LT |
423 | if (!ipcomp6_alloc_scratches()) |
424 | goto error; | |
425 | ||
426 | ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name); | |
427 | if (!ipcd->tfms) | |
428 | goto error; | |
4a3e2f71 | 429 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 | 430 | |
7e49e6de | 431 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
432 | err = ipcomp6_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; | |
442 | out: | |
443 | return err; | |
444 | error_tunnel: | |
4a3e2f71 | 445 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 LT |
446 | error: |
447 | ipcomp6_free_data(ipcd); | |
4a3e2f71 | 448 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 LT |
449 | kfree(ipcd); |
450 | ||
451 | goto out; | |
452 | } | |
453 | ||
1ab1457c | 454 | static struct xfrm_type ipcomp6_type = |
1da177e4 LT |
455 | { |
456 | .description = "IPCOMP6", | |
457 | .owner = THIS_MODULE, | |
458 | .proto = IPPROTO_COMP, | |
459 | .init_state = ipcomp6_init_state, | |
460 | .destructor = ipcomp6_destroy, | |
461 | .input = ipcomp6_input, | |
462 | .output = ipcomp6_output, | |
aee5adb4 | 463 | .hdr_offset = xfrm6_find_1stfragopt, |
1da177e4 LT |
464 | }; |
465 | ||
1ab1457c | 466 | static struct inet6_protocol ipcomp6_protocol = |
1da177e4 LT |
467 | { |
468 | .handler = xfrm6_rcv, | |
469 | .err_handler = ipcomp6_err, | |
470 | .flags = INET6_PROTO_NOPOLICY, | |
471 | }; | |
472 | ||
473 | static int __init ipcomp6_init(void) | |
474 | { | |
475 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { | |
476 | printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); | |
477 | return -EAGAIN; | |
478 | } | |
479 | if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { | |
480 | printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); | |
481 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
482 | return -EAGAIN; | |
483 | } | |
484 | return 0; | |
485 | } | |
486 | ||
487 | static void __exit ipcomp6_fini(void) | |
488 | { | |
1ab1457c | 489 | if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) |
1da177e4 LT |
490 | printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); |
491 | if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) | |
492 | printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); | |
493 | } | |
494 | ||
495 | module_init(ipcomp6_init); | |
496 | module_exit(ipcomp6_fini); | |
497 | MODULE_LICENSE("GPL"); | |
498 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); | |
499 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); | |
500 | ||
d3d6dd3a | 501 | MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); |