Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * IP Payload Compression Protocol (IPComp) - RFC3173. | |
3 | * | |
4 | * Copyright (c) 2003 James Morris <jmorris@intercode.com.au> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License as published by the Free | |
e905a9ed | 8 | * Software Foundation; either version 2 of the License, or (at your option) |
1da177e4 LT |
9 | * any later version. |
10 | * | |
11 | * Todo: | |
12 | * - Tunable compression parameters. | |
13 | * - Compression stats. | |
14 | * - Adaptive compression. | |
15 | */ | |
1da177e4 | 16 | #include <linux/module.h> |
1da177e4 LT |
17 | #include <asm/semaphore.h> |
18 | #include <linux/crypto.h> | |
4999f362 | 19 | #include <linux/err.h> |
1da177e4 LT |
20 | #include <linux/pfkeyv2.h> |
21 | #include <linux/percpu.h> | |
22 | #include <linux/smp.h> | |
23 | #include <linux/list.h> | |
24 | #include <linux/vmalloc.h> | |
25 | #include <linux/rtnetlink.h> | |
4a3e2f71 | 26 | #include <linux/mutex.h> |
1da177e4 LT |
27 | #include <net/ip.h> |
28 | #include <net/xfrm.h> | |
29 | #include <net/icmp.h> | |
30 | #include <net/ipcomp.h> | |
14c85021 | 31 | #include <net/protocol.h> |
1da177e4 LT |
32 | |
33 | struct ipcomp_tfms { | |
34 | struct list_head list; | |
e4d5b79c | 35 | struct crypto_comp **tfms; |
1da177e4 LT |
36 | int users; |
37 | }; | |
38 | ||
4a3e2f71 | 39 | static DEFINE_MUTEX(ipcomp_resource_mutex); |
1da177e4 LT |
40 | static void **ipcomp_scratches; |
41 | static int ipcomp_scratch_users; | |
42 | static LIST_HEAD(ipcomp_tfms_list); | |
43 | ||
44 | static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb) | |
45 | { | |
1da177e4 | 46 | struct ipcomp_data *ipcd = x->data; |
eddc9ec5 ACM |
47 | const int plen = skb->len; |
48 | int dlen = IPCOMP_SCRATCH_SIZE; | |
49 | const u8 *start = skb->data; | |
50 | const int cpu = get_cpu(); | |
51 | u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
52 | struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
53 | int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
e905a9ed | 54 | |
1da177e4 LT |
55 | if (err) |
56 | goto out; | |
57 | ||
58 | if (dlen < (plen + sizeof(struct ip_comp_hdr))) { | |
59 | err = -EINVAL; | |
60 | goto out; | |
61 | } | |
62 | ||
63 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
64 | if (err) | |
65 | goto out; | |
e905a9ed | 66 | |
da952315 HX |
67 | skb->truesize += dlen - plen; |
68 | __skb_put(skb, dlen - plen); | |
27d7ff46 | 69 | skb_copy_to_linear_data(skb, scratch, dlen); |
e905a9ed | 70 | out: |
1da177e4 LT |
71 | put_cpu(); |
72 | return err; | |
73 | } | |
74 | ||
e695633e | 75 | static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 | 76 | { |
2614fa59 | 77 | int nexthdr; |
364c6bad | 78 | int err = -ENOMEM; |
31a4ab93 | 79 | struct ip_comp_hdr *ipch; |
1da177e4 | 80 | |
364c6bad | 81 | if (skb_linearize_cow(skb)) |
e905a9ed | 82 | goto out; |
1da177e4 LT |
83 | |
84 | skb->ip_summed = CHECKSUM_NONE; | |
85 | ||
e905a9ed | 86 | /* Remove ipcomp header and decompress original payload */ |
31a4ab93 | 87 | ipch = (void *)skb->data; |
2614fa59 HX |
88 | nexthdr = ipch->nexthdr; |
89 | ||
b0e380b1 | 90 | skb->transport_header = skb->network_header + sizeof(*ipch); |
31a4ab93 | 91 | __skb_pull(skb, sizeof(*ipch)); |
1da177e4 | 92 | err = ipcomp_decompress(x, skb); |
631a6698 HX |
93 | if (err) |
94 | goto out; | |
95 | ||
2614fa59 | 96 | err = nexthdr; |
1da177e4 | 97 | |
e905a9ed | 98 | out: |
1da177e4 LT |
99 | return err; |
100 | } | |
101 | ||
102 | static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) | |
103 | { | |
1da177e4 | 104 | struct ipcomp_data *ipcd = x->data; |
ceb1eec8 | 105 | const int plen = skb->len; |
eddc9ec5 | 106 | int dlen = IPCOMP_SCRATCH_SIZE; |
ceb1eec8 | 107 | u8 *start = skb->data; |
eddc9ec5 ACM |
108 | const int cpu = get_cpu(); |
109 | u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
110 | struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
111 | int err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
1da177e4 | 112 | |
1da177e4 LT |
113 | if (err) |
114 | goto out; | |
115 | ||
116 | if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) { | |
117 | err = -EMSGSIZE; | |
118 | goto out; | |
119 | } | |
e905a9ed | 120 | |
1da177e4 LT |
121 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); |
122 | put_cpu(); | |
123 | ||
ceb1eec8 | 124 | pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr)); |
1da177e4 | 125 | return 0; |
e905a9ed YH |
126 | |
127 | out: | |
1da177e4 LT |
128 | put_cpu(); |
129 | return err; | |
130 | } | |
131 | ||
132 | static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb) | |
133 | { | |
134 | int err; | |
1da177e4 LT |
135 | struct ip_comp_hdr *ipch; |
136 | struct ipcomp_data *ipcd = x->data; | |
1da177e4 | 137 | |
ceb1eec8 | 138 | if (skb->len < ipcd->threshold) { |
1da177e4 LT |
139 | /* Don't bother compressing */ |
140 | goto out_ok; | |
141 | } | |
142 | ||
364c6bad | 143 | if (skb_linearize_cow(skb)) |
1da177e4 | 144 | goto out_ok; |
e905a9ed | 145 | |
1da177e4 | 146 | err = ipcomp_compress(x, skb); |
1da177e4 LT |
147 | |
148 | if (err) { | |
149 | goto out_ok; | |
150 | } | |
151 | ||
152 | /* Install ipcomp header, convert into ipcomp datagram. */ | |
87bdc48d | 153 | ipch = ip_comp_hdr(skb); |
37fedd3a | 154 | ipch->nexthdr = *skb_mac_header(skb); |
1da177e4 LT |
155 | ipch->flags = 0; |
156 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
37fedd3a | 157 | *skb_mac_header(skb) = IPPROTO_COMP; |
1da177e4 | 158 | out_ok: |
ceb1eec8 | 159 | skb_push(skb, -skb_network_offset(skb)); |
1da177e4 LT |
160 | return 0; |
161 | } | |
162 | ||
163 | static void ipcomp4_err(struct sk_buff *skb, u32 info) | |
164 | { | |
a94cfd19 | 165 | __be32 spi; |
1da177e4 LT |
166 | struct iphdr *iph = (struct iphdr *)skb->data; |
167 | struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); | |
168 | struct xfrm_state *x; | |
169 | ||
88c7664f ACM |
170 | if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH || |
171 | icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) | |
1da177e4 LT |
172 | return; |
173 | ||
4195f814 | 174 | spi = htonl(ntohs(ipch->cpi)); |
1da177e4 | 175 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, |
e905a9ed | 176 | spi, IPPROTO_COMP, AF_INET); |
1da177e4 LT |
177 | if (!x) |
178 | return; | |
64ce2073 PM |
179 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n", |
180 | spi, NIPQUAD(iph->daddr)); | |
1da177e4 LT |
181 | xfrm_state_put(x); |
182 | } | |
183 | ||
e905a9ed | 184 | /* We always hold one tunnel user reference to indicate a tunnel */ |
1da177e4 LT |
185 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) |
186 | { | |
187 | struct xfrm_state *t; | |
e905a9ed | 188 | |
1da177e4 LT |
189 | t = xfrm_state_alloc(); |
190 | if (t == NULL) | |
191 | goto out; | |
192 | ||
193 | t->id.proto = IPPROTO_IPIP; | |
194 | t->id.spi = x->props.saddr.a4; | |
195 | t->id.daddr.a4 = x->id.daddr.a4; | |
196 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
197 | t->props.family = AF_INET; | |
e40b3286 | 198 | t->props.mode = x->props.mode; |
1da177e4 LT |
199 | t->props.saddr.a4 = x->props.saddr.a4; |
200 | t->props.flags = x->props.flags; | |
72cb6962 HX |
201 | |
202 | if (xfrm_init_state(t)) | |
1da177e4 LT |
203 | goto error; |
204 | ||
1da177e4 LT |
205 | atomic_set(&t->tunnel_users, 1); |
206 | out: | |
207 | return t; | |
208 | ||
209 | error: | |
210 | t->km.state = XFRM_STATE_DEAD; | |
211 | xfrm_state_put(t); | |
212 | t = NULL; | |
213 | goto out; | |
214 | } | |
215 | ||
216 | /* | |
4a3e2f71 | 217 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
218 | * always incremented on success. |
219 | */ | |
220 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
221 | { | |
222 | int err = 0; | |
223 | struct xfrm_state *t; | |
224 | ||
225 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4, | |
e905a9ed | 226 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); |
1da177e4 LT |
227 | if (!t) { |
228 | t = ipcomp_tunnel_create(x); | |
229 | if (!t) { | |
230 | err = -EINVAL; | |
231 | goto out; | |
232 | } | |
233 | xfrm_state_insert(t); | |
234 | xfrm_state_hold(t); | |
235 | } | |
236 | x->tunnel = t; | |
237 | atomic_inc(&t->tunnel_users); | |
238 | out: | |
239 | return err; | |
240 | } | |
241 | ||
242 | static void ipcomp_free_scratches(void) | |
243 | { | |
244 | int i; | |
245 | void **scratches; | |
246 | ||
247 | if (--ipcomp_scratch_users) | |
248 | return; | |
249 | ||
250 | scratches = ipcomp_scratches; | |
251 | if (!scratches) | |
252 | return; | |
253 | ||
63903ca6 JJ |
254 | for_each_possible_cpu(i) |
255 | vfree(*per_cpu_ptr(scratches, i)); | |
1da177e4 LT |
256 | |
257 | free_percpu(scratches); | |
258 | } | |
259 | ||
260 | static void **ipcomp_alloc_scratches(void) | |
261 | { | |
262 | int i; | |
263 | void **scratches; | |
264 | ||
265 | if (ipcomp_scratch_users++) | |
266 | return ipcomp_scratches; | |
267 | ||
268 | scratches = alloc_percpu(void *); | |
269 | if (!scratches) | |
270 | return NULL; | |
271 | ||
272 | ipcomp_scratches = scratches; | |
273 | ||
6f912042 | 274 | for_each_possible_cpu(i) { |
1da177e4 LT |
275 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
276 | if (!scratch) | |
277 | return NULL; | |
278 | *per_cpu_ptr(scratches, i) = scratch; | |
279 | } | |
280 | ||
281 | return scratches; | |
282 | } | |
283 | ||
e4d5b79c | 284 | static void ipcomp_free_tfms(struct crypto_comp **tfms) |
1da177e4 LT |
285 | { |
286 | struct ipcomp_tfms *pos; | |
287 | int cpu; | |
288 | ||
289 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
290 | if (pos->tfms == tfms) | |
291 | break; | |
292 | } | |
293 | ||
294 | BUG_TRAP(pos); | |
295 | ||
296 | if (--pos->users) | |
297 | return; | |
298 | ||
299 | list_del(&pos->list); | |
300 | kfree(pos); | |
301 | ||
302 | if (!tfms) | |
303 | return; | |
304 | ||
6f912042 | 305 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
306 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); |
307 | crypto_free_comp(tfm); | |
1da177e4 LT |
308 | } |
309 | free_percpu(tfms); | |
310 | } | |
311 | ||
e4d5b79c | 312 | static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name) |
1da177e4 LT |
313 | { |
314 | struct ipcomp_tfms *pos; | |
e4d5b79c | 315 | struct crypto_comp **tfms; |
1da177e4 LT |
316 | int cpu; |
317 | ||
318 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 319 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
320 | |
321 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
e4d5b79c | 322 | struct crypto_comp *tfm; |
1da177e4 LT |
323 | |
324 | tfms = pos->tfms; | |
325 | tfm = *per_cpu_ptr(tfms, cpu); | |
326 | ||
e4d5b79c | 327 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { |
1da177e4 LT |
328 | pos->users++; |
329 | return tfms; | |
330 | } | |
331 | } | |
332 | ||
333 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
334 | if (!pos) | |
335 | return NULL; | |
336 | ||
337 | pos->users = 1; | |
338 | INIT_LIST_HEAD(&pos->list); | |
339 | list_add(&pos->list, &ipcomp_tfms_list); | |
340 | ||
e4d5b79c | 341 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); |
1da177e4 LT |
342 | if (!tfms) |
343 | goto error; | |
344 | ||
6f912042 | 345 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
346 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0, |
347 | CRYPTO_ALG_ASYNC); | |
4999f362 | 348 | if (IS_ERR(tfm)) |
1da177e4 LT |
349 | goto error; |
350 | *per_cpu_ptr(tfms, cpu) = tfm; | |
351 | } | |
352 | ||
353 | return tfms; | |
354 | ||
355 | error: | |
356 | ipcomp_free_tfms(tfms); | |
357 | return NULL; | |
358 | } | |
359 | ||
360 | static void ipcomp_free_data(struct ipcomp_data *ipcd) | |
361 | { | |
362 | if (ipcd->tfms) | |
363 | ipcomp_free_tfms(ipcd->tfms); | |
364 | ipcomp_free_scratches(); | |
365 | } | |
366 | ||
367 | static void ipcomp_destroy(struct xfrm_state *x) | |
368 | { | |
369 | struct ipcomp_data *ipcd = x->data; | |
370 | if (!ipcd) | |
371 | return; | |
372 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 373 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 | 374 | ipcomp_free_data(ipcd); |
4a3e2f71 | 375 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
376 | kfree(ipcd); |
377 | } | |
378 | ||
72cb6962 | 379 | static int ipcomp_init_state(struct xfrm_state *x) |
1da177e4 LT |
380 | { |
381 | int err; | |
382 | struct ipcomp_data *ipcd; | |
383 | struct xfrm_algo_desc *calg_desc; | |
384 | ||
385 | err = -EINVAL; | |
386 | if (!x->calg) | |
387 | goto out; | |
388 | ||
389 | if (x->encap) | |
390 | goto out; | |
391 | ||
e40b3286 HX |
392 | x->props.header_len = 0; |
393 | switch (x->props.mode) { | |
394 | case XFRM_MODE_TRANSPORT: | |
395 | break; | |
396 | case XFRM_MODE_TUNNEL: | |
397 | x->props.header_len += sizeof(struct iphdr); | |
398 | break; | |
399 | default: | |
400 | goto out; | |
401 | } | |
402 | ||
1da177e4 | 403 | err = -ENOMEM; |
0da974f4 | 404 | ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL); |
1da177e4 LT |
405 | if (!ipcd) |
406 | goto out; | |
407 | ||
4a3e2f71 | 408 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
409 | if (!ipcomp_alloc_scratches()) |
410 | goto error; | |
411 | ||
412 | ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name); | |
413 | if (!ipcd->tfms) | |
414 | goto error; | |
4a3e2f71 | 415 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 | 416 | |
7e49e6de | 417 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
418 | err = ipcomp_tunnel_attach(x); |
419 | if (err) | |
420 | goto error_tunnel; | |
421 | } | |
422 | ||
423 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
424 | BUG_ON(!calg_desc); | |
425 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
426 | x->data = ipcd; | |
427 | err = 0; | |
428 | out: | |
429 | return err; | |
430 | ||
431 | error_tunnel: | |
4a3e2f71 | 432 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
433 | error: |
434 | ipcomp_free_data(ipcd); | |
4a3e2f71 | 435 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
436 | kfree(ipcd); |
437 | goto out; | |
438 | } | |
439 | ||
440 | static struct xfrm_type ipcomp_type = { | |
441 | .description = "IPCOMP4", | |
442 | .owner = THIS_MODULE, | |
443 | .proto = IPPROTO_COMP, | |
444 | .init_state = ipcomp_init_state, | |
445 | .destructor = ipcomp_destroy, | |
446 | .input = ipcomp_input, | |
447 | .output = ipcomp_output | |
448 | }; | |
449 | ||
450 | static struct net_protocol ipcomp4_protocol = { | |
451 | .handler = xfrm4_rcv, | |
452 | .err_handler = ipcomp4_err, | |
453 | .no_policy = 1, | |
454 | }; | |
455 | ||
456 | static int __init ipcomp4_init(void) | |
457 | { | |
458 | if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { | |
459 | printk(KERN_INFO "ipcomp init: can't add xfrm type\n"); | |
460 | return -EAGAIN; | |
461 | } | |
462 | if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) { | |
463 | printk(KERN_INFO "ipcomp init: can't add protocol\n"); | |
464 | xfrm_unregister_type(&ipcomp_type, AF_INET); | |
465 | return -EAGAIN; | |
466 | } | |
467 | return 0; | |
468 | } | |
469 | ||
470 | static void __exit ipcomp4_fini(void) | |
471 | { | |
472 | if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) | |
473 | printk(KERN_INFO "ip ipcomp close: can't remove protocol\n"); | |
474 | if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0) | |
475 | printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n"); | |
476 | } | |
477 | ||
478 | module_init(ipcomp4_init); | |
479 | module_exit(ipcomp4_fini); | |
480 | ||
481 | MODULE_LICENSE("GPL"); | |
482 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173"); | |
483 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
484 | ||
d3d6dd3a | 485 | MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP); |