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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> | |
1da177e4 | 37 | #include <linux/crypto.h> |
4999f362 | 38 | #include <linux/err.h> |
1da177e4 LT |
39 | #include <linux/pfkeyv2.h> |
40 | #include <linux/random.h> | |
41 | #include <linux/percpu.h> | |
42 | #include <linux/smp.h> | |
43 | #include <linux/list.h> | |
44 | #include <linux/vmalloc.h> | |
45 | #include <linux/rtnetlink.h> | |
46 | #include <net/icmp.h> | |
47 | #include <net/ipv6.h> | |
14c85021 | 48 | #include <net/protocol.h> |
1da177e4 LT |
49 | #include <linux/ipv6.h> |
50 | #include <linux/icmpv6.h> | |
4a3e2f71 | 51 | #include <linux/mutex.h> |
1da177e4 LT |
52 | |
53 | struct ipcomp6_tfms { | |
54 | struct list_head list; | |
e4d5b79c | 55 | struct crypto_comp **tfms; |
1da177e4 LT |
56 | int users; |
57 | }; | |
58 | ||
4a3e2f71 | 59 | static DEFINE_MUTEX(ipcomp6_resource_mutex); |
1da177e4 LT |
60 | static void **ipcomp6_scratches; |
61 | static int ipcomp6_scratch_users; | |
62 | static LIST_HEAD(ipcomp6_tfms_list); | |
63 | ||
e695633e | 64 | static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 | 65 | { |
2614fa59 | 66 | int nexthdr; |
364c6bad | 67 | int err = -ENOMEM; |
87bdc48d | 68 | struct ip_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; |
2614fa59 HX |
82 | nexthdr = ipch->nexthdr; |
83 | ||
b0e380b1 | 84 | skb->transport_header = skb->network_header + sizeof(*ipch); |
31a4ab93 | 85 | __skb_pull(skb, sizeof(*ipch)); |
1da177e4 LT |
86 | |
87 | /* decompression */ | |
88 | plen = skb->len; | |
89 | dlen = IPCOMP_SCRATCH_SIZE; | |
90 | start = skb->data; | |
91 | ||
92 | cpu = get_cpu(); | |
93 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
94 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
95 | ||
96 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
87bdc48d | 97 | if (err) |
1da177e4 | 98 | goto out_put_cpu; |
1da177e4 | 99 | |
87bdc48d | 100 | if (dlen < (plen + sizeof(*ipch))) { |
1da177e4 LT |
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); |
2614fa59 | 113 | err = 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; | |
87bdc48d | 124 | struct ip_comp_hdr *ipch; |
1da177e4 LT |
125 | struct ipcomp_data *ipcd = x->data; |
126 | int plen, dlen; | |
127 | u8 *start, *scratch; | |
e4d5b79c | 128 | struct crypto_comp *tfm; |
1da177e4 | 129 | int cpu; |
1da177e4 LT |
130 | |
131 | /* check whether datagram len is larger than threshold */ | |
ceb1eec8 | 132 | if (skb->len < ipcd->threshold) { |
1da177e4 LT |
133 | goto out_ok; |
134 | } | |
135 | ||
364c6bad | 136 | if (skb_linearize_cow(skb)) |
1da177e4 | 137 | goto out_ok; |
1da177e4 LT |
138 | |
139 | /* compression */ | |
ceb1eec8 | 140 | plen = skb->len; |
1da177e4 | 141 | dlen = IPCOMP_SCRATCH_SIZE; |
ceb1eec8 | 142 | start = skb->data; |
1da177e4 LT |
143 | |
144 | cpu = get_cpu(); | |
145 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
146 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
147 | ||
21e43188 | 148 | local_bh_disable(); |
1da177e4 | 149 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); |
21e43188 | 150 | local_bh_enable(); |
87bdc48d | 151 | if (err || (dlen + sizeof(*ipch)) >= plen) { |
1da177e4 LT |
152 | put_cpu(); |
153 | goto out_ok; | |
154 | } | |
155 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
156 | put_cpu(); | |
ceb1eec8 | 157 | pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr)); |
1da177e4 LT |
158 | |
159 | /* insert ipcomp header and replace datagram */ | |
87bdc48d | 160 | ipch = ip_comp_hdr(skb); |
007f0211 | 161 | ipch->nexthdr = *skb_mac_header(skb); |
1da177e4 LT |
162 | ipch->flags = 0; |
163 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
007f0211 | 164 | *skb_mac_header(skb) = IPPROTO_COMP; |
1da177e4 LT |
165 | |
166 | out_ok: | |
ceb1eec8 HX |
167 | skb_push(skb, -skb_network_offset(skb)); |
168 | ||
1da177e4 LT |
169 | return 0; |
170 | } | |
171 | ||
172 | static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
1ab1457c | 173 | int type, int code, int offset, __be32 info) |
1da177e4 | 174 | { |
a94cfd19 | 175 | __be32 spi; |
1da177e4 | 176 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; |
87bdc48d HX |
177 | struct ip_comp_hdr *ipcomph = |
178 | (struct ip_comp_hdr *)(skb->data + offset); | |
1da177e4 LT |
179 | struct xfrm_state *x; |
180 | ||
181 | if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) | |
182 | return; | |
183 | ||
4195f814 | 184 | spi = htonl(ntohs(ipcomph->cpi)); |
1da177e4 LT |
185 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6); |
186 | if (!x) | |
187 | return; | |
188 | ||
46b86a2d | 189 | printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n", |
1da177e4 LT |
190 | spi, NIP6(iph->daddr)); |
191 | xfrm_state_put(x); | |
192 | } | |
193 | ||
194 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) | |
195 | { | |
196 | struct xfrm_state *t = NULL; | |
197 | ||
198 | t = xfrm_state_alloc(); | |
199 | if (!t) | |
200 | goto out; | |
201 | ||
202 | t->id.proto = IPPROTO_IPV6; | |
203 | t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr); | |
6abaaaae HX |
204 | if (!t->id.spi) |
205 | goto error; | |
206 | ||
1da177e4 LT |
207 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); |
208 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
209 | t->props.family = AF_INET6; | |
e40b3286 | 210 | t->props.mode = x->props.mode; |
1da177e4 LT |
211 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); |
212 | ||
72cb6962 | 213 | if (xfrm_init_state(t)) |
1da177e4 LT |
214 | goto error; |
215 | ||
1da177e4 LT |
216 | atomic_set(&t->tunnel_users, 1); |
217 | ||
218 | out: | |
219 | return t; | |
220 | ||
221 | error: | |
6abaaaae | 222 | t->km.state = XFRM_STATE_DEAD; |
1da177e4 | 223 | xfrm_state_put(t); |
6abaaaae | 224 | t = NULL; |
1da177e4 LT |
225 | goto out; |
226 | } | |
227 | ||
228 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) | |
229 | { | |
230 | int err = 0; | |
231 | struct xfrm_state *t = NULL; | |
a94cfd19 | 232 | __be32 spi; |
1da177e4 LT |
233 | |
234 | spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); | |
235 | if (spi) | |
236 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, | |
237 | spi, IPPROTO_IPV6, AF_INET6); | |
238 | if (!t) { | |
239 | t = ipcomp6_tunnel_create(x); | |
240 | if (!t) { | |
241 | err = -EINVAL; | |
242 | goto out; | |
243 | } | |
244 | xfrm_state_insert(t); | |
245 | xfrm_state_hold(t); | |
246 | } | |
247 | x->tunnel = t; | |
248 | atomic_inc(&t->tunnel_users); | |
249 | ||
250 | out: | |
251 | return err; | |
252 | } | |
253 | ||
254 | static void ipcomp6_free_scratches(void) | |
255 | { | |
256 | int i; | |
257 | void **scratches; | |
258 | ||
259 | if (--ipcomp6_scratch_users) | |
260 | return; | |
261 | ||
262 | scratches = ipcomp6_scratches; | |
263 | if (!scratches) | |
264 | return; | |
265 | ||
6f912042 | 266 | for_each_possible_cpu(i) { |
1da177e4 | 267 | void *scratch = *per_cpu_ptr(scratches, i); |
2b191bef JJ |
268 | |
269 | vfree(scratch); | |
1da177e4 LT |
270 | } |
271 | ||
272 | free_percpu(scratches); | |
273 | } | |
274 | ||
275 | static void **ipcomp6_alloc_scratches(void) | |
276 | { | |
277 | int i; | |
278 | void **scratches; | |
279 | ||
280 | if (ipcomp6_scratch_users++) | |
281 | return ipcomp6_scratches; | |
282 | ||
283 | scratches = alloc_percpu(void *); | |
284 | if (!scratches) | |
285 | return NULL; | |
286 | ||
287 | ipcomp6_scratches = scratches; | |
288 | ||
6f912042 | 289 | for_each_possible_cpu(i) { |
1da177e4 LT |
290 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
291 | if (!scratch) | |
292 | return NULL; | |
293 | *per_cpu_ptr(scratches, i) = scratch; | |
294 | } | |
295 | ||
296 | return scratches; | |
297 | } | |
298 | ||
e4d5b79c | 299 | static void ipcomp6_free_tfms(struct crypto_comp **tfms) |
1da177e4 LT |
300 | { |
301 | struct ipcomp6_tfms *pos; | |
302 | int cpu; | |
303 | ||
304 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
305 | if (pos->tfms == tfms) | |
306 | break; | |
307 | } | |
308 | ||
309 | BUG_TRAP(pos); | |
310 | ||
311 | if (--pos->users) | |
312 | return; | |
313 | ||
314 | list_del(&pos->list); | |
315 | kfree(pos); | |
316 | ||
317 | if (!tfms) | |
318 | return; | |
319 | ||
6f912042 | 320 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
321 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); |
322 | crypto_free_comp(tfm); | |
1da177e4 LT |
323 | } |
324 | free_percpu(tfms); | |
325 | } | |
326 | ||
e4d5b79c | 327 | static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name) |
1da177e4 LT |
328 | { |
329 | struct ipcomp6_tfms *pos; | |
e4d5b79c | 330 | struct crypto_comp **tfms; |
1da177e4 LT |
331 | int cpu; |
332 | ||
333 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 334 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
335 | |
336 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
e4d5b79c | 337 | struct crypto_comp *tfm; |
1da177e4 LT |
338 | |
339 | tfms = pos->tfms; | |
340 | tfm = *per_cpu_ptr(tfms, cpu); | |
341 | ||
e4d5b79c | 342 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { |
1da177e4 LT |
343 | pos->users++; |
344 | return tfms; | |
345 | } | |
346 | } | |
347 | ||
348 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
349 | if (!pos) | |
350 | return NULL; | |
351 | ||
352 | pos->users = 1; | |
353 | INIT_LIST_HEAD(&pos->list); | |
354 | list_add(&pos->list, &ipcomp6_tfms_list); | |
355 | ||
e4d5b79c | 356 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); |
1da177e4 LT |
357 | if (!tfms) |
358 | goto error; | |
359 | ||
6f912042 | 360 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
361 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0, |
362 | CRYPTO_ALG_ASYNC); | |
4999f362 | 363 | if (IS_ERR(tfm)) |
1da177e4 LT |
364 | goto error; |
365 | *per_cpu_ptr(tfms, cpu) = tfm; | |
366 | } | |
367 | ||
368 | return tfms; | |
369 | ||
370 | error: | |
371 | ipcomp6_free_tfms(tfms); | |
372 | return NULL; | |
373 | } | |
374 | ||
375 | static void ipcomp6_free_data(struct ipcomp_data *ipcd) | |
376 | { | |
377 | if (ipcd->tfms) | |
378 | ipcomp6_free_tfms(ipcd->tfms); | |
379 | ipcomp6_free_scratches(); | |
380 | } | |
381 | ||
382 | static void ipcomp6_destroy(struct xfrm_state *x) | |
383 | { | |
384 | struct ipcomp_data *ipcd = x->data; | |
385 | if (!ipcd) | |
386 | return; | |
387 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 388 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 | 389 | ipcomp6_free_data(ipcd); |
4a3e2f71 | 390 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 LT |
391 | kfree(ipcd); |
392 | ||
393 | xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr); | |
394 | } | |
395 | ||
72cb6962 | 396 | static int ipcomp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
397 | { |
398 | int err; | |
399 | struct ipcomp_data *ipcd; | |
400 | struct xfrm_algo_desc *calg_desc; | |
401 | ||
402 | err = -EINVAL; | |
403 | if (!x->calg) | |
404 | goto out; | |
405 | ||
406 | if (x->encap) | |
407 | goto out; | |
408 | ||
1da177e4 | 409 | x->props.header_len = 0; |
ca68145f | 410 | switch (x->props.mode) { |
ca68145f HX |
411 | case XFRM_MODE_TRANSPORT: |
412 | break; | |
413 | case XFRM_MODE_TUNNEL: | |
1da177e4 | 414 | x->props.header_len += sizeof(struct ipv6hdr); |
e40b3286 | 415 | break; |
ca68145f | 416 | default: |
e40b3286 | 417 | goto out; |
ca68145f | 418 | } |
1ab1457c | 419 | |
e40b3286 HX |
420 | err = -ENOMEM; |
421 | ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL); | |
422 | if (!ipcd) | |
423 | goto out; | |
424 | ||
4a3e2f71 | 425 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 LT |
426 | if (!ipcomp6_alloc_scratches()) |
427 | goto error; | |
428 | ||
429 | ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name); | |
430 | if (!ipcd->tfms) | |
431 | goto error; | |
4a3e2f71 | 432 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 | 433 | |
7e49e6de | 434 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
435 | err = ipcomp6_tunnel_attach(x); |
436 | if (err) | |
437 | goto error_tunnel; | |
438 | } | |
439 | ||
440 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
441 | BUG_ON(!calg_desc); | |
442 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
443 | x->data = ipcd; | |
444 | err = 0; | |
445 | out: | |
446 | return err; | |
447 | error_tunnel: | |
4a3e2f71 | 448 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 LT |
449 | error: |
450 | ipcomp6_free_data(ipcd); | |
4a3e2f71 | 451 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 LT |
452 | kfree(ipcd); |
453 | ||
454 | goto out; | |
455 | } | |
456 | ||
533cb5b0 | 457 | static const struct xfrm_type ipcomp6_type = |
1da177e4 LT |
458 | { |
459 | .description = "IPCOMP6", | |
460 | .owner = THIS_MODULE, | |
461 | .proto = IPPROTO_COMP, | |
462 | .init_state = ipcomp6_init_state, | |
463 | .destructor = ipcomp6_destroy, | |
464 | .input = ipcomp6_input, | |
465 | .output = ipcomp6_output, | |
aee5adb4 | 466 | .hdr_offset = xfrm6_find_1stfragopt, |
1da177e4 LT |
467 | }; |
468 | ||
1ab1457c | 469 | static struct inet6_protocol ipcomp6_protocol = |
1da177e4 LT |
470 | { |
471 | .handler = xfrm6_rcv, | |
472 | .err_handler = ipcomp6_err, | |
473 | .flags = INET6_PROTO_NOPOLICY, | |
474 | }; | |
475 | ||
476 | static int __init ipcomp6_init(void) | |
477 | { | |
478 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { | |
479 | printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); | |
480 | return -EAGAIN; | |
481 | } | |
482 | if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { | |
483 | printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); | |
484 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
485 | return -EAGAIN; | |
486 | } | |
487 | return 0; | |
488 | } | |
489 | ||
490 | static void __exit ipcomp6_fini(void) | |
491 | { | |
1ab1457c | 492 | if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) |
1da177e4 LT |
493 | printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); |
494 | if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) | |
495 | printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); | |
496 | } | |
497 | ||
498 | module_init(ipcomp6_init); | |
499 | module_exit(ipcomp6_fini); | |
500 | MODULE_LICENSE("GPL"); | |
501 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); | |
502 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); | |
503 | ||
d3d6dd3a | 504 | MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); |