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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. | |
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 | */ | |
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; |
1da177e4 | 68 | struct ipv6hdr *iph; |
31a4ab93 | 69 | struct ipv6_comp_hdr *ipch; |
1da177e4 LT |
70 | int plen, dlen; |
71 | struct ipcomp_data *ipcd = x->data; | |
72 | u8 *start, *scratch; | |
e4d5b79c | 73 | struct crypto_comp *tfm; |
1da177e4 LT |
74 | int cpu; |
75 | ||
364c6bad | 76 | if (skb_linearize_cow(skb)) |
1da177e4 | 77 | goto out; |
1da177e4 LT |
78 | |
79 | skb->ip_summed = CHECKSUM_NONE; | |
80 | ||
81 | /* Remove ipcomp header and decompress original payload */ | |
82 | iph = skb->nh.ipv6h; | |
31a4ab93 HX |
83 | ipch = (void *)skb->data; |
84 | skb->h.raw = skb->nh.raw + sizeof(*ipch); | |
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); | |
97 | if (err) { | |
98 | err = -EINVAL; | |
99 | goto out_put_cpu; | |
100 | } | |
101 | ||
102 | if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) { | |
103 | err = -EINVAL; | |
104 | goto out_put_cpu; | |
105 | } | |
106 | ||
107 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
108 | if (err) { | |
109 | goto out_put_cpu; | |
110 | } | |
111 | ||
da952315 HX |
112 | skb->truesize += dlen - plen; |
113 | __skb_put(skb, dlen - plen); | |
1da177e4 | 114 | memcpy(skb->data, scratch, dlen); |
31a4ab93 | 115 | err = ipch->nexthdr; |
1da177e4 | 116 | |
1da177e4 LT |
117 | out_put_cpu: |
118 | put_cpu(); | |
119 | out: | |
1da177e4 LT |
120 | return err; |
121 | } | |
122 | ||
123 | static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb) | |
124 | { | |
125 | int err; | |
126 | struct ipv6hdr *top_iph; | |
127 | int hdr_len; | |
128 | struct ipv6_comp_hdr *ipch; | |
129 | struct ipcomp_data *ipcd = x->data; | |
130 | int plen, dlen; | |
131 | u8 *start, *scratch; | |
e4d5b79c | 132 | struct crypto_comp *tfm; |
1da177e4 LT |
133 | int cpu; |
134 | ||
135 | hdr_len = skb->h.raw - skb->data; | |
136 | ||
137 | /* check whether datagram len is larger than threshold */ | |
138 | if ((skb->len - hdr_len) < ipcd->threshold) { | |
139 | goto out_ok; | |
140 | } | |
141 | ||
364c6bad | 142 | if (skb_linearize_cow(skb)) |
1da177e4 | 143 | goto out_ok; |
1da177e4 LT |
144 | |
145 | /* compression */ | |
146 | plen = skb->len - hdr_len; | |
147 | dlen = IPCOMP_SCRATCH_SIZE; | |
148 | start = skb->h.raw; | |
149 | ||
150 | cpu = get_cpu(); | |
151 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
152 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
153 | ||
154 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
155 | if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) { | |
156 | put_cpu(); | |
157 | goto out_ok; | |
158 | } | |
159 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
160 | put_cpu(); | |
161 | pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr)); | |
162 | ||
163 | /* insert ipcomp header and replace datagram */ | |
164 | top_iph = (struct ipv6hdr *)skb->data; | |
165 | ||
166 | top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); | |
167 | ||
168 | ipch = (struct ipv6_comp_hdr *)start; | |
169 | ipch->nexthdr = *skb->nh.raw; | |
170 | ipch->flags = 0; | |
171 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
172 | *skb->nh.raw = IPPROTO_COMP; | |
173 | ||
174 | out_ok: | |
175 | return 0; | |
176 | } | |
177 | ||
178 | static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
04ce6909 | 179 | int type, int code, int offset, __be32 info) |
1da177e4 | 180 | { |
a94cfd19 | 181 | __be32 spi; |
1da177e4 LT |
182 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; |
183 | struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset); | |
184 | struct xfrm_state *x; | |
185 | ||
186 | if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) | |
187 | return; | |
188 | ||
4195f814 | 189 | spi = htonl(ntohs(ipcomph->cpi)); |
1da177e4 LT |
190 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6); |
191 | if (!x) | |
192 | return; | |
193 | ||
46b86a2d | 194 | printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n", |
1da177e4 LT |
195 | spi, NIP6(iph->daddr)); |
196 | xfrm_state_put(x); | |
197 | } | |
198 | ||
199 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) | |
200 | { | |
201 | struct xfrm_state *t = NULL; | |
0a69452c | 202 | u8 mode = XFRM_MODE_TUNNEL; |
1da177e4 LT |
203 | |
204 | t = xfrm_state_alloc(); | |
205 | if (!t) | |
206 | goto out; | |
207 | ||
208 | t->id.proto = IPPROTO_IPV6; | |
209 | t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr); | |
6abaaaae HX |
210 | if (!t->id.spi) |
211 | goto error; | |
212 | ||
1da177e4 LT |
213 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); |
214 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
215 | t->props.family = AF_INET6; | |
0a69452c DB |
216 | if (x->props.mode == XFRM_MODE_BEET) |
217 | mode = x->props.mode; | |
218 | t->props.mode = mode; | |
1da177e4 LT |
219 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); |
220 | ||
72cb6962 | 221 | if (xfrm_init_state(t)) |
1da177e4 LT |
222 | goto error; |
223 | ||
1da177e4 LT |
224 | atomic_set(&t->tunnel_users, 1); |
225 | ||
226 | out: | |
227 | return t; | |
228 | ||
229 | error: | |
6abaaaae | 230 | t->km.state = XFRM_STATE_DEAD; |
1da177e4 | 231 | xfrm_state_put(t); |
6abaaaae | 232 | t = NULL; |
1da177e4 LT |
233 | goto out; |
234 | } | |
235 | ||
236 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) | |
237 | { | |
238 | int err = 0; | |
239 | struct xfrm_state *t = NULL; | |
a94cfd19 | 240 | __be32 spi; |
1da177e4 LT |
241 | |
242 | spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); | |
243 | if (spi) | |
244 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, | |
245 | spi, IPPROTO_IPV6, AF_INET6); | |
246 | if (!t) { | |
247 | t = ipcomp6_tunnel_create(x); | |
248 | if (!t) { | |
249 | err = -EINVAL; | |
250 | goto out; | |
251 | } | |
252 | xfrm_state_insert(t); | |
253 | xfrm_state_hold(t); | |
254 | } | |
255 | x->tunnel = t; | |
256 | atomic_inc(&t->tunnel_users); | |
257 | ||
258 | out: | |
259 | return err; | |
260 | } | |
261 | ||
262 | static void ipcomp6_free_scratches(void) | |
263 | { | |
264 | int i; | |
265 | void **scratches; | |
266 | ||
267 | if (--ipcomp6_scratch_users) | |
268 | return; | |
269 | ||
270 | scratches = ipcomp6_scratches; | |
271 | if (!scratches) | |
272 | return; | |
273 | ||
6f912042 | 274 | for_each_possible_cpu(i) { |
1da177e4 | 275 | void *scratch = *per_cpu_ptr(scratches, i); |
2b191bef JJ |
276 | |
277 | vfree(scratch); | |
1da177e4 LT |
278 | } |
279 | ||
280 | free_percpu(scratches); | |
281 | } | |
282 | ||
283 | static void **ipcomp6_alloc_scratches(void) | |
284 | { | |
285 | int i; | |
286 | void **scratches; | |
287 | ||
288 | if (ipcomp6_scratch_users++) | |
289 | return ipcomp6_scratches; | |
290 | ||
291 | scratches = alloc_percpu(void *); | |
292 | if (!scratches) | |
293 | return NULL; | |
294 | ||
295 | ipcomp6_scratches = scratches; | |
296 | ||
6f912042 | 297 | for_each_possible_cpu(i) { |
1da177e4 LT |
298 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
299 | if (!scratch) | |
300 | return NULL; | |
301 | *per_cpu_ptr(scratches, i) = scratch; | |
302 | } | |
303 | ||
304 | return scratches; | |
305 | } | |
306 | ||
e4d5b79c | 307 | static void ipcomp6_free_tfms(struct crypto_comp **tfms) |
1da177e4 LT |
308 | { |
309 | struct ipcomp6_tfms *pos; | |
310 | int cpu; | |
311 | ||
312 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
313 | if (pos->tfms == tfms) | |
314 | break; | |
315 | } | |
316 | ||
317 | BUG_TRAP(pos); | |
318 | ||
319 | if (--pos->users) | |
320 | return; | |
321 | ||
322 | list_del(&pos->list); | |
323 | kfree(pos); | |
324 | ||
325 | if (!tfms) | |
326 | return; | |
327 | ||
6f912042 | 328 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
329 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); |
330 | crypto_free_comp(tfm); | |
1da177e4 LT |
331 | } |
332 | free_percpu(tfms); | |
333 | } | |
334 | ||
e4d5b79c | 335 | static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name) |
1da177e4 LT |
336 | { |
337 | struct ipcomp6_tfms *pos; | |
e4d5b79c | 338 | struct crypto_comp **tfms; |
1da177e4 LT |
339 | int cpu; |
340 | ||
341 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 342 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
343 | |
344 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
e4d5b79c | 345 | struct crypto_comp *tfm; |
1da177e4 LT |
346 | |
347 | tfms = pos->tfms; | |
348 | tfm = *per_cpu_ptr(tfms, cpu); | |
349 | ||
e4d5b79c | 350 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { |
1da177e4 LT |
351 | pos->users++; |
352 | return tfms; | |
353 | } | |
354 | } | |
355 | ||
356 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
357 | if (!pos) | |
358 | return NULL; | |
359 | ||
360 | pos->users = 1; | |
361 | INIT_LIST_HEAD(&pos->list); | |
362 | list_add(&pos->list, &ipcomp6_tfms_list); | |
363 | ||
e4d5b79c | 364 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); |
1da177e4 LT |
365 | if (!tfms) |
366 | goto error; | |
367 | ||
6f912042 | 368 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
369 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0, |
370 | CRYPTO_ALG_ASYNC); | |
1da177e4 LT |
371 | if (!tfm) |
372 | goto error; | |
373 | *per_cpu_ptr(tfms, cpu) = tfm; | |
374 | } | |
375 | ||
376 | return tfms; | |
377 | ||
378 | error: | |
379 | ipcomp6_free_tfms(tfms); | |
380 | return NULL; | |
381 | } | |
382 | ||
383 | static void ipcomp6_free_data(struct ipcomp_data *ipcd) | |
384 | { | |
385 | if (ipcd->tfms) | |
386 | ipcomp6_free_tfms(ipcd->tfms); | |
387 | ipcomp6_free_scratches(); | |
388 | } | |
389 | ||
390 | static void ipcomp6_destroy(struct xfrm_state *x) | |
391 | { | |
392 | struct ipcomp_data *ipcd = x->data; | |
393 | if (!ipcd) | |
394 | return; | |
395 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 396 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 | 397 | ipcomp6_free_data(ipcd); |
4a3e2f71 | 398 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 LT |
399 | kfree(ipcd); |
400 | ||
401 | xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr); | |
402 | } | |
403 | ||
72cb6962 | 404 | static int ipcomp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
405 | { |
406 | int err; | |
407 | struct ipcomp_data *ipcd; | |
408 | struct xfrm_algo_desc *calg_desc; | |
409 | ||
410 | err = -EINVAL; | |
411 | if (!x->calg) | |
412 | goto out; | |
413 | ||
414 | if (x->encap) | |
415 | goto out; | |
416 | ||
417 | err = -ENOMEM; | |
0c600eda | 418 | ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL); |
1da177e4 LT |
419 | if (!ipcd) |
420 | goto out; | |
421 | ||
1da177e4 | 422 | x->props.header_len = 0; |
7e49e6de | 423 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
424 | x->props.header_len += sizeof(struct ipv6hdr); |
425 | ||
4a3e2f71 | 426 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 LT |
427 | if (!ipcomp6_alloc_scratches()) |
428 | goto error; | |
429 | ||
430 | ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name); | |
431 | if (!ipcd->tfms) | |
432 | goto error; | |
4a3e2f71 | 433 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 | 434 | |
7e49e6de | 435 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
436 | err = ipcomp6_tunnel_attach(x); |
437 | if (err) | |
438 | goto error_tunnel; | |
439 | } | |
440 | ||
441 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
442 | BUG_ON(!calg_desc); | |
443 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
444 | x->data = ipcd; | |
445 | err = 0; | |
446 | out: | |
447 | return err; | |
448 | error_tunnel: | |
4a3e2f71 | 449 | mutex_lock(&ipcomp6_resource_mutex); |
1da177e4 LT |
450 | error: |
451 | ipcomp6_free_data(ipcd); | |
4a3e2f71 | 452 | mutex_unlock(&ipcomp6_resource_mutex); |
1da177e4 LT |
453 | kfree(ipcd); |
454 | ||
455 | goto out; | |
456 | } | |
457 | ||
458 | static struct xfrm_type ipcomp6_type = | |
459 | { | |
460 | .description = "IPCOMP6", | |
461 | .owner = THIS_MODULE, | |
462 | .proto = IPPROTO_COMP, | |
463 | .init_state = ipcomp6_init_state, | |
464 | .destructor = ipcomp6_destroy, | |
465 | .input = ipcomp6_input, | |
466 | .output = ipcomp6_output, | |
aee5adb4 | 467 | .hdr_offset = xfrm6_find_1stfragopt, |
1da177e4 LT |
468 | }; |
469 | ||
470 | static struct inet6_protocol ipcomp6_protocol = | |
471 | { | |
472 | .handler = xfrm6_rcv, | |
473 | .err_handler = ipcomp6_err, | |
474 | .flags = INET6_PROTO_NOPOLICY, | |
475 | }; | |
476 | ||
477 | static int __init ipcomp6_init(void) | |
478 | { | |
479 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { | |
480 | printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); | |
481 | return -EAGAIN; | |
482 | } | |
483 | if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { | |
484 | printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); | |
485 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
486 | return -EAGAIN; | |
487 | } | |
488 | return 0; | |
489 | } | |
490 | ||
491 | static void __exit ipcomp6_fini(void) | |
492 | { | |
493 | if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) | |
494 | printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); | |
495 | if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) | |
496 | printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); | |
497 | } | |
498 | ||
499 | module_init(ipcomp6_init); | |
500 | module_exit(ipcomp6_fini); | |
501 | MODULE_LICENSE("GPL"); | |
502 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); | |
503 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); | |
504 | ||
505 |