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 LT |
16 | #include <linux/module.h> |
17 | #include <asm/scatterlist.h> | |
18 | #include <asm/semaphore.h> | |
19 | #include <linux/crypto.h> | |
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 | { | |
46 | int err, plen, dlen; | |
1da177e4 LT |
47 | struct ipcomp_data *ipcd = x->data; |
48 | u8 *start, *scratch; | |
e4d5b79c | 49 | struct crypto_comp *tfm; |
1da177e4 | 50 | int cpu; |
e905a9ed | 51 | |
1da177e4 LT |
52 | plen = skb->len; |
53 | dlen = IPCOMP_SCRATCH_SIZE; | |
54 | start = skb->data; | |
55 | ||
56 | cpu = get_cpu(); | |
57 | scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
58 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
59 | ||
60 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
61 | if (err) | |
62 | goto out; | |
63 | ||
64 | if (dlen < (plen + sizeof(struct ip_comp_hdr))) { | |
65 | err = -EINVAL; | |
66 | goto out; | |
67 | } | |
68 | ||
69 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
70 | if (err) | |
71 | goto out; | |
e905a9ed | 72 | |
da952315 HX |
73 | skb->truesize += dlen - plen; |
74 | __skb_put(skb, dlen - plen); | |
1da177e4 | 75 | memcpy(skb->data, scratch, dlen); |
e905a9ed | 76 | out: |
1da177e4 LT |
77 | put_cpu(); |
78 | return err; | |
79 | } | |
80 | ||
e695633e | 81 | static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 | 82 | { |
364c6bad | 83 | int err = -ENOMEM; |
1da177e4 | 84 | struct iphdr *iph; |
31a4ab93 | 85 | struct ip_comp_hdr *ipch; |
1da177e4 | 86 | |
364c6bad | 87 | if (skb_linearize_cow(skb)) |
e905a9ed | 88 | goto out; |
1da177e4 LT |
89 | |
90 | skb->ip_summed = CHECKSUM_NONE; | |
91 | ||
e905a9ed | 92 | /* Remove ipcomp header and decompress original payload */ |
1da177e4 | 93 | iph = skb->nh.iph; |
31a4ab93 HX |
94 | ipch = (void *)skb->data; |
95 | iph->protocol = ipch->nexthdr; | |
96 | skb->h.raw = skb->nh.raw + sizeof(*ipch); | |
97 | __skb_pull(skb, sizeof(*ipch)); | |
1da177e4 LT |
98 | err = ipcomp_decompress(x, skb); |
99 | ||
e905a9ed | 100 | out: |
1da177e4 LT |
101 | return err; |
102 | } | |
103 | ||
104 | static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) | |
105 | { | |
106 | int err, plen, dlen, ihlen; | |
107 | struct iphdr *iph = skb->nh.iph; | |
108 | struct ipcomp_data *ipcd = x->data; | |
109 | u8 *start, *scratch; | |
e4d5b79c | 110 | struct crypto_comp *tfm; |
1da177e4 | 111 | int cpu; |
e905a9ed | 112 | |
1da177e4 LT |
113 | ihlen = iph->ihl * 4; |
114 | plen = skb->len - ihlen; | |
115 | dlen = IPCOMP_SCRATCH_SIZE; | |
116 | start = skb->data + ihlen; | |
117 | ||
118 | cpu = get_cpu(); | |
119 | scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
120 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
121 | ||
122 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
123 | if (err) | |
124 | goto out; | |
125 | ||
126 | if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) { | |
127 | err = -EMSGSIZE; | |
128 | goto out; | |
129 | } | |
e905a9ed | 130 | |
1da177e4 LT |
131 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); |
132 | put_cpu(); | |
133 | ||
134 | pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr)); | |
135 | return 0; | |
e905a9ed YH |
136 | |
137 | out: | |
1da177e4 LT |
138 | put_cpu(); |
139 | return err; | |
140 | } | |
141 | ||
142 | static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb) | |
143 | { | |
144 | int err; | |
145 | struct iphdr *iph; | |
146 | struct ip_comp_hdr *ipch; | |
147 | struct ipcomp_data *ipcd = x->data; | |
148 | int hdr_len = 0; | |
149 | ||
150 | iph = skb->nh.iph; | |
151 | iph->tot_len = htons(skb->len); | |
152 | hdr_len = iph->ihl * 4; | |
153 | if ((skb->len - hdr_len) < ipcd->threshold) { | |
154 | /* Don't bother compressing */ | |
155 | goto out_ok; | |
156 | } | |
157 | ||
364c6bad | 158 | if (skb_linearize_cow(skb)) |
1da177e4 | 159 | goto out_ok; |
e905a9ed | 160 | |
1da177e4 LT |
161 | err = ipcomp_compress(x, skb); |
162 | iph = skb->nh.iph; | |
163 | ||
164 | if (err) { | |
165 | goto out_ok; | |
166 | } | |
167 | ||
168 | /* Install ipcomp header, convert into ipcomp datagram. */ | |
169 | iph->tot_len = htons(skb->len); | |
170 | ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4); | |
171 | ipch->nexthdr = iph->protocol; | |
172 | ipch->flags = 0; | |
173 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
174 | iph->protocol = IPPROTO_COMP; | |
175 | ip_send_check(iph); | |
176 | return 0; | |
177 | ||
178 | out_ok: | |
7e49e6de | 179 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
180 | ip_send_check(iph); |
181 | return 0; | |
182 | } | |
183 | ||
184 | static void ipcomp4_err(struct sk_buff *skb, u32 info) | |
185 | { | |
a94cfd19 | 186 | __be32 spi; |
1da177e4 LT |
187 | struct iphdr *iph = (struct iphdr *)skb->data; |
188 | struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); | |
189 | struct xfrm_state *x; | |
190 | ||
191 | if (skb->h.icmph->type != ICMP_DEST_UNREACH || | |
192 | skb->h.icmph->code != ICMP_FRAG_NEEDED) | |
193 | return; | |
194 | ||
4195f814 | 195 | spi = htonl(ntohs(ipch->cpi)); |
1da177e4 | 196 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, |
e905a9ed | 197 | spi, IPPROTO_COMP, AF_INET); |
1da177e4 LT |
198 | if (!x) |
199 | return; | |
64ce2073 PM |
200 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n", |
201 | spi, NIPQUAD(iph->daddr)); | |
1da177e4 LT |
202 | xfrm_state_put(x); |
203 | } | |
204 | ||
e905a9ed | 205 | /* We always hold one tunnel user reference to indicate a tunnel */ |
1da177e4 LT |
206 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) |
207 | { | |
208 | struct xfrm_state *t; | |
0a69452c | 209 | u8 mode = XFRM_MODE_TUNNEL; |
e905a9ed | 210 | |
1da177e4 LT |
211 | t = xfrm_state_alloc(); |
212 | if (t == NULL) | |
213 | goto out; | |
214 | ||
215 | t->id.proto = IPPROTO_IPIP; | |
216 | t->id.spi = x->props.saddr.a4; | |
217 | t->id.daddr.a4 = x->id.daddr.a4; | |
218 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
219 | t->props.family = AF_INET; | |
0a69452c DB |
220 | if (x->props.mode == XFRM_MODE_BEET) |
221 | mode = x->props.mode; | |
222 | t->props.mode = mode; | |
1da177e4 LT |
223 | t->props.saddr.a4 = x->props.saddr.a4; |
224 | t->props.flags = x->props.flags; | |
72cb6962 HX |
225 | |
226 | if (xfrm_init_state(t)) | |
1da177e4 LT |
227 | goto error; |
228 | ||
1da177e4 LT |
229 | atomic_set(&t->tunnel_users, 1); |
230 | out: | |
231 | return t; | |
232 | ||
233 | error: | |
234 | t->km.state = XFRM_STATE_DEAD; | |
235 | xfrm_state_put(t); | |
236 | t = NULL; | |
237 | goto out; | |
238 | } | |
239 | ||
240 | /* | |
4a3e2f71 | 241 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
242 | * always incremented on success. |
243 | */ | |
244 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
245 | { | |
246 | int err = 0; | |
247 | struct xfrm_state *t; | |
248 | ||
249 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4, | |
e905a9ed | 250 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); |
1da177e4 LT |
251 | if (!t) { |
252 | t = ipcomp_tunnel_create(x); | |
253 | if (!t) { | |
254 | err = -EINVAL; | |
255 | goto out; | |
256 | } | |
257 | xfrm_state_insert(t); | |
258 | xfrm_state_hold(t); | |
259 | } | |
260 | x->tunnel = t; | |
261 | atomic_inc(&t->tunnel_users); | |
262 | out: | |
263 | return err; | |
264 | } | |
265 | ||
266 | static void ipcomp_free_scratches(void) | |
267 | { | |
268 | int i; | |
269 | void **scratches; | |
270 | ||
271 | if (--ipcomp_scratch_users) | |
272 | return; | |
273 | ||
274 | scratches = ipcomp_scratches; | |
275 | if (!scratches) | |
276 | return; | |
277 | ||
63903ca6 JJ |
278 | for_each_possible_cpu(i) |
279 | vfree(*per_cpu_ptr(scratches, i)); | |
1da177e4 LT |
280 | |
281 | free_percpu(scratches); | |
282 | } | |
283 | ||
284 | static void **ipcomp_alloc_scratches(void) | |
285 | { | |
286 | int i; | |
287 | void **scratches; | |
288 | ||
289 | if (ipcomp_scratch_users++) | |
290 | return ipcomp_scratches; | |
291 | ||
292 | scratches = alloc_percpu(void *); | |
293 | if (!scratches) | |
294 | return NULL; | |
295 | ||
296 | ipcomp_scratches = scratches; | |
297 | ||
6f912042 | 298 | for_each_possible_cpu(i) { |
1da177e4 LT |
299 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
300 | if (!scratch) | |
301 | return NULL; | |
302 | *per_cpu_ptr(scratches, i) = scratch; | |
303 | } | |
304 | ||
305 | return scratches; | |
306 | } | |
307 | ||
e4d5b79c | 308 | static void ipcomp_free_tfms(struct crypto_comp **tfms) |
1da177e4 LT |
309 | { |
310 | struct ipcomp_tfms *pos; | |
311 | int cpu; | |
312 | ||
313 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
314 | if (pos->tfms == tfms) | |
315 | break; | |
316 | } | |
317 | ||
318 | BUG_TRAP(pos); | |
319 | ||
320 | if (--pos->users) | |
321 | return; | |
322 | ||
323 | list_del(&pos->list); | |
324 | kfree(pos); | |
325 | ||
326 | if (!tfms) | |
327 | return; | |
328 | ||
6f912042 | 329 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
330 | struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu); |
331 | crypto_free_comp(tfm); | |
1da177e4 LT |
332 | } |
333 | free_percpu(tfms); | |
334 | } | |
335 | ||
e4d5b79c | 336 | static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name) |
1da177e4 LT |
337 | { |
338 | struct ipcomp_tfms *pos; | |
e4d5b79c | 339 | struct crypto_comp **tfms; |
1da177e4 LT |
340 | int cpu; |
341 | ||
342 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 343 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
344 | |
345 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
e4d5b79c | 346 | struct crypto_comp *tfm; |
1da177e4 LT |
347 | |
348 | tfms = pos->tfms; | |
349 | tfm = *per_cpu_ptr(tfms, cpu); | |
350 | ||
e4d5b79c | 351 | if (!strcmp(crypto_comp_name(tfm), alg_name)) { |
1da177e4 LT |
352 | pos->users++; |
353 | return tfms; | |
354 | } | |
355 | } | |
356 | ||
357 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
358 | if (!pos) | |
359 | return NULL; | |
360 | ||
361 | pos->users = 1; | |
362 | INIT_LIST_HEAD(&pos->list); | |
363 | list_add(&pos->list, &ipcomp_tfms_list); | |
364 | ||
e4d5b79c | 365 | pos->tfms = tfms = alloc_percpu(struct crypto_comp *); |
1da177e4 LT |
366 | if (!tfms) |
367 | goto error; | |
368 | ||
6f912042 | 369 | for_each_possible_cpu(cpu) { |
e4d5b79c HX |
370 | struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0, |
371 | CRYPTO_ALG_ASYNC); | |
1da177e4 LT |
372 | if (!tfm) |
373 | goto error; | |
374 | *per_cpu_ptr(tfms, cpu) = tfm; | |
375 | } | |
376 | ||
377 | return tfms; | |
378 | ||
379 | error: | |
380 | ipcomp_free_tfms(tfms); | |
381 | return NULL; | |
382 | } | |
383 | ||
384 | static void ipcomp_free_data(struct ipcomp_data *ipcd) | |
385 | { | |
386 | if (ipcd->tfms) | |
387 | ipcomp_free_tfms(ipcd->tfms); | |
388 | ipcomp_free_scratches(); | |
389 | } | |
390 | ||
391 | static void ipcomp_destroy(struct xfrm_state *x) | |
392 | { | |
393 | struct ipcomp_data *ipcd = x->data; | |
394 | if (!ipcd) | |
395 | return; | |
396 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 397 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 | 398 | ipcomp_free_data(ipcd); |
4a3e2f71 | 399 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
400 | kfree(ipcd); |
401 | } | |
402 | ||
72cb6962 | 403 | static int ipcomp_init_state(struct xfrm_state *x) |
1da177e4 LT |
404 | { |
405 | int err; | |
406 | struct ipcomp_data *ipcd; | |
407 | struct xfrm_algo_desc *calg_desc; | |
408 | ||
409 | err = -EINVAL; | |
410 | if (!x->calg) | |
411 | goto out; | |
412 | ||
413 | if (x->encap) | |
414 | goto out; | |
415 | ||
416 | err = -ENOMEM; | |
0da974f4 | 417 | ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL); |
1da177e4 LT |
418 | if (!ipcd) |
419 | goto out; | |
420 | ||
1da177e4 | 421 | x->props.header_len = 0; |
7e49e6de | 422 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
423 | x->props.header_len += sizeof(struct iphdr); |
424 | ||
4a3e2f71 | 425 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
426 | if (!ipcomp_alloc_scratches()) |
427 | goto error; | |
428 | ||
429 | ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name); | |
430 | if (!ipcd->tfms) | |
431 | goto error; | |
4a3e2f71 | 432 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 | 433 | |
7e49e6de | 434 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
435 | err = ipcomp_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 | ||
448 | error_tunnel: | |
4a3e2f71 | 449 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
450 | error: |
451 | ipcomp_free_data(ipcd); | |
4a3e2f71 | 452 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
453 | kfree(ipcd); |
454 | goto out; | |
455 | } | |
456 | ||
457 | static struct xfrm_type ipcomp_type = { | |
458 | .description = "IPCOMP4", | |
459 | .owner = THIS_MODULE, | |
460 | .proto = IPPROTO_COMP, | |
461 | .init_state = ipcomp_init_state, | |
462 | .destructor = ipcomp_destroy, | |
463 | .input = ipcomp_input, | |
464 | .output = ipcomp_output | |
465 | }; | |
466 | ||
467 | static struct net_protocol ipcomp4_protocol = { | |
468 | .handler = xfrm4_rcv, | |
469 | .err_handler = ipcomp4_err, | |
470 | .no_policy = 1, | |
471 | }; | |
472 | ||
473 | static int __init ipcomp4_init(void) | |
474 | { | |
475 | if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { | |
476 | printk(KERN_INFO "ipcomp init: can't add xfrm type\n"); | |
477 | return -EAGAIN; | |
478 | } | |
479 | if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) { | |
480 | printk(KERN_INFO "ipcomp init: can't add protocol\n"); | |
481 | xfrm_unregister_type(&ipcomp_type, AF_INET); | |
482 | return -EAGAIN; | |
483 | } | |
484 | return 0; | |
485 | } | |
486 | ||
487 | static void __exit ipcomp4_fini(void) | |
488 | { | |
489 | if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) | |
490 | printk(KERN_INFO "ip ipcomp close: can't remove protocol\n"); | |
491 | if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0) | |
492 | printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n"); | |
493 | } | |
494 | ||
495 | module_init(ipcomp4_init); | |
496 | module_exit(ipcomp4_fini); | |
497 | ||
498 | MODULE_LICENSE("GPL"); | |
499 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173"); | |
500 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
501 |