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Commit | Line | Data |
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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 | |
8 | * Software Foundation; either version 2 of the License, or (at your option) | |
9 | * any later version. | |
10 | * | |
11 | * Todo: | |
12 | * - Tunable compression parameters. | |
13 | * - Compression stats. | |
14 | * - Adaptive compression. | |
15 | */ | |
16 | #include <linux/config.h> | |
17 | #include <linux/module.h> | |
18 | #include <asm/scatterlist.h> | |
19 | #include <asm/semaphore.h> | |
20 | #include <linux/crypto.h> | |
21 | #include <linux/pfkeyv2.h> | |
22 | #include <linux/percpu.h> | |
23 | #include <linux/smp.h> | |
24 | #include <linux/list.h> | |
25 | #include <linux/vmalloc.h> | |
26 | #include <linux/rtnetlink.h> | |
4a3e2f71 | 27 | #include <linux/mutex.h> |
1da177e4 LT |
28 | #include <net/ip.h> |
29 | #include <net/xfrm.h> | |
30 | #include <net/icmp.h> | |
31 | #include <net/ipcomp.h> | |
14c85021 | 32 | #include <net/protocol.h> |
1da177e4 LT |
33 | |
34 | struct ipcomp_tfms { | |
35 | struct list_head list; | |
36 | struct crypto_tfm **tfms; | |
37 | int users; | |
38 | }; | |
39 | ||
4a3e2f71 | 40 | static DEFINE_MUTEX(ipcomp_resource_mutex); |
1da177e4 LT |
41 | static void **ipcomp_scratches; |
42 | static int ipcomp_scratch_users; | |
43 | static LIST_HEAD(ipcomp_tfms_list); | |
44 | ||
45 | static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb) | |
46 | { | |
47 | int err, plen, dlen; | |
1da177e4 LT |
48 | struct ipcomp_data *ipcd = x->data; |
49 | u8 *start, *scratch; | |
50 | struct crypto_tfm *tfm; | |
51 | int cpu; | |
52 | ||
53 | plen = skb->len; | |
54 | dlen = IPCOMP_SCRATCH_SIZE; | |
55 | start = skb->data; | |
56 | ||
57 | cpu = get_cpu(); | |
58 | scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
59 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
60 | ||
61 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
62 | if (err) | |
63 | goto out; | |
64 | ||
65 | if (dlen < (plen + sizeof(struct ip_comp_hdr))) { | |
66 | err = -EINVAL; | |
67 | goto out; | |
68 | } | |
69 | ||
70 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
71 | if (err) | |
72 | goto out; | |
73 | ||
74 | skb_put(skb, dlen - plen); | |
75 | memcpy(skb->data, scratch, dlen); | |
1da177e4 LT |
76 | out: |
77 | put_cpu(); | |
78 | return err; | |
79 | } | |
80 | ||
e695633e | 81 | static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 | 82 | { |
1da177e4 LT |
83 | int err = 0; |
84 | struct iphdr *iph; | |
31a4ab93 | 85 | struct ip_comp_hdr *ipch; |
1da177e4 LT |
86 | |
87 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && | |
88 | skb_linearize(skb, GFP_ATOMIC) != 0) { | |
89 | err = -ENOMEM; | |
90 | goto out; | |
91 | } | |
92 | ||
93 | skb->ip_summed = CHECKSUM_NONE; | |
94 | ||
95 | /* Remove ipcomp header and decompress original payload */ | |
96 | iph = skb->nh.iph; | |
31a4ab93 HX |
97 | ipch = (void *)skb->data; |
98 | iph->protocol = ipch->nexthdr; | |
99 | skb->h.raw = skb->nh.raw + sizeof(*ipch); | |
100 | __skb_pull(skb, sizeof(*ipch)); | |
1da177e4 LT |
101 | err = ipcomp_decompress(x, skb); |
102 | ||
103 | out: | |
104 | return err; | |
105 | } | |
106 | ||
107 | static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) | |
108 | { | |
109 | int err, plen, dlen, ihlen; | |
110 | struct iphdr *iph = skb->nh.iph; | |
111 | struct ipcomp_data *ipcd = x->data; | |
112 | u8 *start, *scratch; | |
113 | struct crypto_tfm *tfm; | |
114 | int cpu; | |
115 | ||
116 | ihlen = iph->ihl * 4; | |
117 | plen = skb->len - ihlen; | |
118 | dlen = IPCOMP_SCRATCH_SIZE; | |
119 | start = skb->data + ihlen; | |
120 | ||
121 | cpu = get_cpu(); | |
122 | scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
123 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
124 | ||
125 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
126 | if (err) | |
127 | goto out; | |
128 | ||
129 | if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) { | |
130 | err = -EMSGSIZE; | |
131 | goto out; | |
132 | } | |
133 | ||
134 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
135 | put_cpu(); | |
136 | ||
137 | pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr)); | |
138 | return 0; | |
139 | ||
140 | out: | |
141 | put_cpu(); | |
142 | return err; | |
143 | } | |
144 | ||
145 | static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb) | |
146 | { | |
147 | int err; | |
148 | struct iphdr *iph; | |
149 | struct ip_comp_hdr *ipch; | |
150 | struct ipcomp_data *ipcd = x->data; | |
151 | int hdr_len = 0; | |
152 | ||
153 | iph = skb->nh.iph; | |
154 | iph->tot_len = htons(skb->len); | |
155 | hdr_len = iph->ihl * 4; | |
156 | if ((skb->len - hdr_len) < ipcd->threshold) { | |
157 | /* Don't bother compressing */ | |
158 | goto out_ok; | |
159 | } | |
160 | ||
161 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && | |
162 | skb_linearize(skb, GFP_ATOMIC) != 0) { | |
163 | goto out_ok; | |
164 | } | |
165 | ||
166 | err = ipcomp_compress(x, skb); | |
167 | iph = skb->nh.iph; | |
168 | ||
169 | if (err) { | |
170 | goto out_ok; | |
171 | } | |
172 | ||
173 | /* Install ipcomp header, convert into ipcomp datagram. */ | |
174 | iph->tot_len = htons(skb->len); | |
175 | ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4); | |
176 | ipch->nexthdr = iph->protocol; | |
177 | ipch->flags = 0; | |
178 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
179 | iph->protocol = IPPROTO_COMP; | |
180 | ip_send_check(iph); | |
181 | return 0; | |
182 | ||
183 | out_ok: | |
184 | if (x->props.mode) | |
185 | ip_send_check(iph); | |
186 | return 0; | |
187 | } | |
188 | ||
189 | static void ipcomp4_err(struct sk_buff *skb, u32 info) | |
190 | { | |
191 | u32 spi; | |
192 | struct iphdr *iph = (struct iphdr *)skb->data; | |
193 | struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); | |
194 | struct xfrm_state *x; | |
195 | ||
196 | if (skb->h.icmph->type != ICMP_DEST_UNREACH || | |
197 | skb->h.icmph->code != ICMP_FRAG_NEEDED) | |
198 | return; | |
199 | ||
4195f814 | 200 | spi = htonl(ntohs(ipch->cpi)); |
1da177e4 LT |
201 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, |
202 | spi, IPPROTO_COMP, AF_INET); | |
203 | if (!x) | |
204 | return; | |
64ce2073 PM |
205 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n", |
206 | spi, NIPQUAD(iph->daddr)); | |
1da177e4 LT |
207 | xfrm_state_put(x); |
208 | } | |
209 | ||
210 | /* We always hold one tunnel user reference to indicate a tunnel */ | |
211 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) | |
212 | { | |
213 | struct xfrm_state *t; | |
214 | ||
215 | t = xfrm_state_alloc(); | |
216 | if (t == NULL) | |
217 | goto out; | |
218 | ||
219 | t->id.proto = IPPROTO_IPIP; | |
220 | t->id.spi = x->props.saddr.a4; | |
221 | t->id.daddr.a4 = x->id.daddr.a4; | |
222 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
223 | t->props.family = AF_INET; | |
224 | t->props.mode = 1; | |
225 | t->props.saddr.a4 = x->props.saddr.a4; | |
226 | t->props.flags = x->props.flags; | |
72cb6962 HX |
227 | |
228 | if (xfrm_init_state(t)) | |
1da177e4 LT |
229 | goto error; |
230 | ||
1da177e4 LT |
231 | atomic_set(&t->tunnel_users, 1); |
232 | out: | |
233 | return t; | |
234 | ||
235 | error: | |
236 | t->km.state = XFRM_STATE_DEAD; | |
237 | xfrm_state_put(t); | |
238 | t = NULL; | |
239 | goto out; | |
240 | } | |
241 | ||
242 | /* | |
4a3e2f71 | 243 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
244 | * always incremented on success. |
245 | */ | |
246 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
247 | { | |
248 | int err = 0; | |
249 | struct xfrm_state *t; | |
250 | ||
251 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4, | |
252 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); | |
253 | if (!t) { | |
254 | t = ipcomp_tunnel_create(x); | |
255 | if (!t) { | |
256 | err = -EINVAL; | |
257 | goto out; | |
258 | } | |
259 | xfrm_state_insert(t); | |
260 | xfrm_state_hold(t); | |
261 | } | |
262 | x->tunnel = t; | |
263 | atomic_inc(&t->tunnel_users); | |
264 | out: | |
265 | return err; | |
266 | } | |
267 | ||
268 | static void ipcomp_free_scratches(void) | |
269 | { | |
270 | int i; | |
271 | void **scratches; | |
272 | ||
273 | if (--ipcomp_scratch_users) | |
274 | return; | |
275 | ||
276 | scratches = ipcomp_scratches; | |
277 | if (!scratches) | |
278 | return; | |
279 | ||
63903ca6 JJ |
280 | for_each_possible_cpu(i) |
281 | vfree(*per_cpu_ptr(scratches, i)); | |
1da177e4 LT |
282 | |
283 | free_percpu(scratches); | |
284 | } | |
285 | ||
286 | static void **ipcomp_alloc_scratches(void) | |
287 | { | |
288 | int i; | |
289 | void **scratches; | |
290 | ||
291 | if (ipcomp_scratch_users++) | |
292 | return ipcomp_scratches; | |
293 | ||
294 | scratches = alloc_percpu(void *); | |
295 | if (!scratches) | |
296 | return NULL; | |
297 | ||
298 | ipcomp_scratches = scratches; | |
299 | ||
6f912042 | 300 | for_each_possible_cpu(i) { |
1da177e4 LT |
301 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
302 | if (!scratch) | |
303 | return NULL; | |
304 | *per_cpu_ptr(scratches, i) = scratch; | |
305 | } | |
306 | ||
307 | return scratches; | |
308 | } | |
309 | ||
310 | static void ipcomp_free_tfms(struct crypto_tfm **tfms) | |
311 | { | |
312 | struct ipcomp_tfms *pos; | |
313 | int cpu; | |
314 | ||
315 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
316 | if (pos->tfms == tfms) | |
317 | break; | |
318 | } | |
319 | ||
320 | BUG_TRAP(pos); | |
321 | ||
322 | if (--pos->users) | |
323 | return; | |
324 | ||
325 | list_del(&pos->list); | |
326 | kfree(pos); | |
327 | ||
328 | if (!tfms) | |
329 | return; | |
330 | ||
6f912042 | 331 | for_each_possible_cpu(cpu) { |
1da177e4 | 332 | struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu); |
573dbd95 | 333 | crypto_free_tfm(tfm); |
1da177e4 LT |
334 | } |
335 | free_percpu(tfms); | |
336 | } | |
337 | ||
338 | static struct crypto_tfm **ipcomp_alloc_tfms(const char *alg_name) | |
339 | { | |
340 | struct ipcomp_tfms *pos; | |
341 | struct crypto_tfm **tfms; | |
342 | int cpu; | |
343 | ||
344 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 345 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
346 | |
347 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
348 | struct crypto_tfm *tfm; | |
349 | ||
350 | tfms = pos->tfms; | |
351 | tfm = *per_cpu_ptr(tfms, cpu); | |
352 | ||
353 | if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) { | |
354 | pos->users++; | |
355 | return tfms; | |
356 | } | |
357 | } | |
358 | ||
359 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
360 | if (!pos) | |
361 | return NULL; | |
362 | ||
363 | pos->users = 1; | |
364 | INIT_LIST_HEAD(&pos->list); | |
365 | list_add(&pos->list, &ipcomp_tfms_list); | |
366 | ||
367 | pos->tfms = tfms = alloc_percpu(struct crypto_tfm *); | |
368 | if (!tfms) | |
369 | goto error; | |
370 | ||
6f912042 | 371 | for_each_possible_cpu(cpu) { |
1da177e4 LT |
372 | struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0); |
373 | if (!tfm) | |
374 | goto error; | |
375 | *per_cpu_ptr(tfms, cpu) = tfm; | |
376 | } | |
377 | ||
378 | return tfms; | |
379 | ||
380 | error: | |
381 | ipcomp_free_tfms(tfms); | |
382 | return NULL; | |
383 | } | |
384 | ||
385 | static void ipcomp_free_data(struct ipcomp_data *ipcd) | |
386 | { | |
387 | if (ipcd->tfms) | |
388 | ipcomp_free_tfms(ipcd->tfms); | |
389 | ipcomp_free_scratches(); | |
390 | } | |
391 | ||
392 | static void ipcomp_destroy(struct xfrm_state *x) | |
393 | { | |
394 | struct ipcomp_data *ipcd = x->data; | |
395 | if (!ipcd) | |
396 | return; | |
397 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 398 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 | 399 | ipcomp_free_data(ipcd); |
4a3e2f71 | 400 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
401 | kfree(ipcd); |
402 | } | |
403 | ||
72cb6962 | 404 | static int ipcomp_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; | |
418 | ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL); | |
419 | if (!ipcd) | |
420 | goto out; | |
421 | ||
422 | memset(ipcd, 0, sizeof(*ipcd)); | |
423 | x->props.header_len = 0; | |
424 | if (x->props.mode) | |
425 | x->props.header_len += sizeof(struct iphdr); | |
426 | ||
4a3e2f71 | 427 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
428 | if (!ipcomp_alloc_scratches()) |
429 | goto error; | |
430 | ||
431 | ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name); | |
432 | if (!ipcd->tfms) | |
433 | goto error; | |
4a3e2f71 | 434 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
435 | |
436 | if (x->props.mode) { | |
437 | err = ipcomp_tunnel_attach(x); | |
438 | if (err) | |
439 | goto error_tunnel; | |
440 | } | |
441 | ||
442 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
443 | BUG_ON(!calg_desc); | |
444 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
445 | x->data = ipcd; | |
446 | err = 0; | |
447 | out: | |
448 | return err; | |
449 | ||
450 | error_tunnel: | |
4a3e2f71 | 451 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
452 | error: |
453 | ipcomp_free_data(ipcd); | |
4a3e2f71 | 454 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
455 | kfree(ipcd); |
456 | goto out; | |
457 | } | |
458 | ||
459 | static struct xfrm_type ipcomp_type = { | |
460 | .description = "IPCOMP4", | |
461 | .owner = THIS_MODULE, | |
462 | .proto = IPPROTO_COMP, | |
463 | .init_state = ipcomp_init_state, | |
464 | .destructor = ipcomp_destroy, | |
465 | .input = ipcomp_input, | |
466 | .output = ipcomp_output | |
467 | }; | |
468 | ||
469 | static struct net_protocol ipcomp4_protocol = { | |
470 | .handler = xfrm4_rcv, | |
471 | .err_handler = ipcomp4_err, | |
472 | .no_policy = 1, | |
473 | }; | |
474 | ||
475 | static int __init ipcomp4_init(void) | |
476 | { | |
477 | if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { | |
478 | printk(KERN_INFO "ipcomp init: can't add xfrm type\n"); | |
479 | return -EAGAIN; | |
480 | } | |
481 | if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) { | |
482 | printk(KERN_INFO "ipcomp init: can't add protocol\n"); | |
483 | xfrm_unregister_type(&ipcomp_type, AF_INET); | |
484 | return -EAGAIN; | |
485 | } | |
486 | return 0; | |
487 | } | |
488 | ||
489 | static void __exit ipcomp4_fini(void) | |
490 | { | |
491 | if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) | |
492 | printk(KERN_INFO "ip ipcomp close: can't remove protocol\n"); | |
493 | if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0) | |
494 | printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n"); | |
495 | } | |
496 | ||
497 | module_init(ipcomp4_init); | |
498 | module_exit(ipcomp4_fini); | |
499 | ||
500 | MODULE_LICENSE("GPL"); | |
501 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173"); | |
502 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
503 |