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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; | |
48 | struct iphdr *iph; | |
49 | struct ipcomp_data *ipcd = x->data; | |
50 | u8 *start, *scratch; | |
51 | struct crypto_tfm *tfm; | |
52 | int cpu; | |
53 | ||
54 | plen = skb->len; | |
55 | dlen = IPCOMP_SCRATCH_SIZE; | |
56 | start = skb->data; | |
57 | ||
58 | cpu = get_cpu(); | |
59 | scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
60 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
61 | ||
62 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
63 | if (err) | |
64 | goto out; | |
65 | ||
66 | if (dlen < (plen + sizeof(struct ip_comp_hdr))) { | |
67 | err = -EINVAL; | |
68 | goto out; | |
69 | } | |
70 | ||
71 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
72 | if (err) | |
73 | goto out; | |
74 | ||
75 | skb_put(skb, dlen - plen); | |
76 | memcpy(skb->data, scratch, dlen); | |
77 | iph = skb->nh.iph; | |
78 | iph->tot_len = htons(dlen + iph->ihl * 4); | |
79 | out: | |
80 | put_cpu(); | |
81 | return err; | |
82 | } | |
83 | ||
e695633e | 84 | static int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 LT |
85 | { |
86 | u8 nexthdr; | |
87 | int err = 0; | |
88 | struct iphdr *iph; | |
89 | union { | |
90 | struct iphdr iph; | |
91 | char buf[60]; | |
92 | } tmp_iph; | |
93 | ||
94 | ||
95 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && | |
96 | skb_linearize(skb, GFP_ATOMIC) != 0) { | |
97 | err = -ENOMEM; | |
98 | goto out; | |
99 | } | |
100 | ||
101 | skb->ip_summed = CHECKSUM_NONE; | |
102 | ||
103 | /* Remove ipcomp header and decompress original payload */ | |
104 | iph = skb->nh.iph; | |
105 | memcpy(&tmp_iph, iph, iph->ihl * 4); | |
106 | nexthdr = *(u8 *)skb->data; | |
107 | skb_pull(skb, sizeof(struct ip_comp_hdr)); | |
108 | skb->nh.raw += sizeof(struct ip_comp_hdr); | |
109 | memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4); | |
110 | iph = skb->nh.iph; | |
111 | iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr)); | |
112 | iph->protocol = nexthdr; | |
113 | skb->h.raw = skb->data; | |
114 | err = ipcomp_decompress(x, skb); | |
115 | ||
116 | out: | |
117 | return err; | |
118 | } | |
119 | ||
120 | static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) | |
121 | { | |
122 | int err, plen, dlen, ihlen; | |
123 | struct iphdr *iph = skb->nh.iph; | |
124 | struct ipcomp_data *ipcd = x->data; | |
125 | u8 *start, *scratch; | |
126 | struct crypto_tfm *tfm; | |
127 | int cpu; | |
128 | ||
129 | ihlen = iph->ihl * 4; | |
130 | plen = skb->len - ihlen; | |
131 | dlen = IPCOMP_SCRATCH_SIZE; | |
132 | start = skb->data + ihlen; | |
133 | ||
134 | cpu = get_cpu(); | |
135 | scratch = *per_cpu_ptr(ipcomp_scratches, cpu); | |
136 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
137 | ||
138 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
139 | if (err) | |
140 | goto out; | |
141 | ||
142 | if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) { | |
143 | err = -EMSGSIZE; | |
144 | goto out; | |
145 | } | |
146 | ||
147 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
148 | put_cpu(); | |
149 | ||
150 | pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr)); | |
151 | return 0; | |
152 | ||
153 | out: | |
154 | put_cpu(); | |
155 | return err; | |
156 | } | |
157 | ||
158 | static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb) | |
159 | { | |
160 | int err; | |
161 | struct iphdr *iph; | |
162 | struct ip_comp_hdr *ipch; | |
163 | struct ipcomp_data *ipcd = x->data; | |
164 | int hdr_len = 0; | |
165 | ||
166 | iph = skb->nh.iph; | |
167 | iph->tot_len = htons(skb->len); | |
168 | hdr_len = iph->ihl * 4; | |
169 | if ((skb->len - hdr_len) < ipcd->threshold) { | |
170 | /* Don't bother compressing */ | |
171 | goto out_ok; | |
172 | } | |
173 | ||
174 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && | |
175 | skb_linearize(skb, GFP_ATOMIC) != 0) { | |
176 | goto out_ok; | |
177 | } | |
178 | ||
179 | err = ipcomp_compress(x, skb); | |
180 | iph = skb->nh.iph; | |
181 | ||
182 | if (err) { | |
183 | goto out_ok; | |
184 | } | |
185 | ||
186 | /* Install ipcomp header, convert into ipcomp datagram. */ | |
187 | iph->tot_len = htons(skb->len); | |
188 | ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4); | |
189 | ipch->nexthdr = iph->protocol; | |
190 | ipch->flags = 0; | |
191 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
192 | iph->protocol = IPPROTO_COMP; | |
193 | ip_send_check(iph); | |
194 | return 0; | |
195 | ||
196 | out_ok: | |
197 | if (x->props.mode) | |
198 | ip_send_check(iph); | |
199 | return 0; | |
200 | } | |
201 | ||
202 | static void ipcomp4_err(struct sk_buff *skb, u32 info) | |
203 | { | |
204 | u32 spi; | |
205 | struct iphdr *iph = (struct iphdr *)skb->data; | |
206 | struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); | |
207 | struct xfrm_state *x; | |
208 | ||
209 | if (skb->h.icmph->type != ICMP_DEST_UNREACH || | |
210 | skb->h.icmph->code != ICMP_FRAG_NEEDED) | |
211 | return; | |
212 | ||
213 | spi = ntohl(ntohs(ipch->cpi)); | |
214 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, | |
215 | spi, IPPROTO_COMP, AF_INET); | |
216 | if (!x) | |
217 | return; | |
64ce2073 PM |
218 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n", |
219 | spi, NIPQUAD(iph->daddr)); | |
1da177e4 LT |
220 | xfrm_state_put(x); |
221 | } | |
222 | ||
223 | /* We always hold one tunnel user reference to indicate a tunnel */ | |
224 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) | |
225 | { | |
226 | struct xfrm_state *t; | |
227 | ||
228 | t = xfrm_state_alloc(); | |
229 | if (t == NULL) | |
230 | goto out; | |
231 | ||
232 | t->id.proto = IPPROTO_IPIP; | |
233 | t->id.spi = x->props.saddr.a4; | |
234 | t->id.daddr.a4 = x->id.daddr.a4; | |
235 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
236 | t->props.family = AF_INET; | |
237 | t->props.mode = 1; | |
238 | t->props.saddr.a4 = x->props.saddr.a4; | |
239 | t->props.flags = x->props.flags; | |
72cb6962 HX |
240 | |
241 | if (xfrm_init_state(t)) | |
1da177e4 LT |
242 | goto error; |
243 | ||
1da177e4 LT |
244 | atomic_set(&t->tunnel_users, 1); |
245 | out: | |
246 | return t; | |
247 | ||
248 | error: | |
249 | t->km.state = XFRM_STATE_DEAD; | |
250 | xfrm_state_put(t); | |
251 | t = NULL; | |
252 | goto out; | |
253 | } | |
254 | ||
255 | /* | |
4a3e2f71 | 256 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
257 | * always incremented on success. |
258 | */ | |
259 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
260 | { | |
261 | int err = 0; | |
262 | struct xfrm_state *t; | |
263 | ||
264 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4, | |
265 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); | |
266 | if (!t) { | |
267 | t = ipcomp_tunnel_create(x); | |
268 | if (!t) { | |
269 | err = -EINVAL; | |
270 | goto out; | |
271 | } | |
272 | xfrm_state_insert(t); | |
273 | xfrm_state_hold(t); | |
274 | } | |
275 | x->tunnel = t; | |
276 | atomic_inc(&t->tunnel_users); | |
277 | out: | |
278 | return err; | |
279 | } | |
280 | ||
281 | static void ipcomp_free_scratches(void) | |
282 | { | |
283 | int i; | |
284 | void **scratches; | |
285 | ||
286 | if (--ipcomp_scratch_users) | |
287 | return; | |
288 | ||
289 | scratches = ipcomp_scratches; | |
290 | if (!scratches) | |
291 | return; | |
292 | ||
6f912042 | 293 | for_each_possible_cpu(i) { |
1da177e4 LT |
294 | void *scratch = *per_cpu_ptr(scratches, i); |
295 | if (scratch) | |
296 | vfree(scratch); | |
297 | } | |
298 | ||
299 | free_percpu(scratches); | |
300 | } | |
301 | ||
302 | static void **ipcomp_alloc_scratches(void) | |
303 | { | |
304 | int i; | |
305 | void **scratches; | |
306 | ||
307 | if (ipcomp_scratch_users++) | |
308 | return ipcomp_scratches; | |
309 | ||
310 | scratches = alloc_percpu(void *); | |
311 | if (!scratches) | |
312 | return NULL; | |
313 | ||
314 | ipcomp_scratches = scratches; | |
315 | ||
6f912042 | 316 | for_each_possible_cpu(i) { |
1da177e4 LT |
317 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
318 | if (!scratch) | |
319 | return NULL; | |
320 | *per_cpu_ptr(scratches, i) = scratch; | |
321 | } | |
322 | ||
323 | return scratches; | |
324 | } | |
325 | ||
326 | static void ipcomp_free_tfms(struct crypto_tfm **tfms) | |
327 | { | |
328 | struct ipcomp_tfms *pos; | |
329 | int cpu; | |
330 | ||
331 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
332 | if (pos->tfms == tfms) | |
333 | break; | |
334 | } | |
335 | ||
336 | BUG_TRAP(pos); | |
337 | ||
338 | if (--pos->users) | |
339 | return; | |
340 | ||
341 | list_del(&pos->list); | |
342 | kfree(pos); | |
343 | ||
344 | if (!tfms) | |
345 | return; | |
346 | ||
6f912042 | 347 | for_each_possible_cpu(cpu) { |
1da177e4 | 348 | struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu); |
573dbd95 | 349 | crypto_free_tfm(tfm); |
1da177e4 LT |
350 | } |
351 | free_percpu(tfms); | |
352 | } | |
353 | ||
354 | static struct crypto_tfm **ipcomp_alloc_tfms(const char *alg_name) | |
355 | { | |
356 | struct ipcomp_tfms *pos; | |
357 | struct crypto_tfm **tfms; | |
358 | int cpu; | |
359 | ||
360 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 361 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
362 | |
363 | list_for_each_entry(pos, &ipcomp_tfms_list, list) { | |
364 | struct crypto_tfm *tfm; | |
365 | ||
366 | tfms = pos->tfms; | |
367 | tfm = *per_cpu_ptr(tfms, cpu); | |
368 | ||
369 | if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) { | |
370 | pos->users++; | |
371 | return tfms; | |
372 | } | |
373 | } | |
374 | ||
375 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
376 | if (!pos) | |
377 | return NULL; | |
378 | ||
379 | pos->users = 1; | |
380 | INIT_LIST_HEAD(&pos->list); | |
381 | list_add(&pos->list, &ipcomp_tfms_list); | |
382 | ||
383 | pos->tfms = tfms = alloc_percpu(struct crypto_tfm *); | |
384 | if (!tfms) | |
385 | goto error; | |
386 | ||
6f912042 | 387 | for_each_possible_cpu(cpu) { |
1da177e4 LT |
388 | struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0); |
389 | if (!tfm) | |
390 | goto error; | |
391 | *per_cpu_ptr(tfms, cpu) = tfm; | |
392 | } | |
393 | ||
394 | return tfms; | |
395 | ||
396 | error: | |
397 | ipcomp_free_tfms(tfms); | |
398 | return NULL; | |
399 | } | |
400 | ||
401 | static void ipcomp_free_data(struct ipcomp_data *ipcd) | |
402 | { | |
403 | if (ipcd->tfms) | |
404 | ipcomp_free_tfms(ipcd->tfms); | |
405 | ipcomp_free_scratches(); | |
406 | } | |
407 | ||
408 | static void ipcomp_destroy(struct xfrm_state *x) | |
409 | { | |
410 | struct ipcomp_data *ipcd = x->data; | |
411 | if (!ipcd) | |
412 | return; | |
413 | xfrm_state_delete_tunnel(x); | |
4a3e2f71 | 414 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 | 415 | ipcomp_free_data(ipcd); |
4a3e2f71 | 416 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
417 | kfree(ipcd); |
418 | } | |
419 | ||
72cb6962 | 420 | static int ipcomp_init_state(struct xfrm_state *x) |
1da177e4 LT |
421 | { |
422 | int err; | |
423 | struct ipcomp_data *ipcd; | |
424 | struct xfrm_algo_desc *calg_desc; | |
425 | ||
426 | err = -EINVAL; | |
427 | if (!x->calg) | |
428 | goto out; | |
429 | ||
430 | if (x->encap) | |
431 | goto out; | |
432 | ||
433 | err = -ENOMEM; | |
434 | ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL); | |
435 | if (!ipcd) | |
436 | goto out; | |
437 | ||
438 | memset(ipcd, 0, sizeof(*ipcd)); | |
439 | x->props.header_len = 0; | |
440 | if (x->props.mode) | |
441 | x->props.header_len += sizeof(struct iphdr); | |
442 | ||
4a3e2f71 | 443 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
444 | if (!ipcomp_alloc_scratches()) |
445 | goto error; | |
446 | ||
447 | ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name); | |
448 | if (!ipcd->tfms) | |
449 | goto error; | |
4a3e2f71 | 450 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
451 | |
452 | if (x->props.mode) { | |
453 | err = ipcomp_tunnel_attach(x); | |
454 | if (err) | |
455 | goto error_tunnel; | |
456 | } | |
457 | ||
458 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
459 | BUG_ON(!calg_desc); | |
460 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
461 | x->data = ipcd; | |
462 | err = 0; | |
463 | out: | |
464 | return err; | |
465 | ||
466 | error_tunnel: | |
4a3e2f71 | 467 | mutex_lock(&ipcomp_resource_mutex); |
1da177e4 LT |
468 | error: |
469 | ipcomp_free_data(ipcd); | |
4a3e2f71 | 470 | mutex_unlock(&ipcomp_resource_mutex); |
1da177e4 LT |
471 | kfree(ipcd); |
472 | goto out; | |
473 | } | |
474 | ||
475 | static struct xfrm_type ipcomp_type = { | |
476 | .description = "IPCOMP4", | |
477 | .owner = THIS_MODULE, | |
478 | .proto = IPPROTO_COMP, | |
479 | .init_state = ipcomp_init_state, | |
480 | .destructor = ipcomp_destroy, | |
481 | .input = ipcomp_input, | |
482 | .output = ipcomp_output | |
483 | }; | |
484 | ||
485 | static struct net_protocol ipcomp4_protocol = { | |
486 | .handler = xfrm4_rcv, | |
487 | .err_handler = ipcomp4_err, | |
488 | .no_policy = 1, | |
489 | }; | |
490 | ||
491 | static int __init ipcomp4_init(void) | |
492 | { | |
493 | if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { | |
494 | printk(KERN_INFO "ipcomp init: can't add xfrm type\n"); | |
495 | return -EAGAIN; | |
496 | } | |
497 | if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) { | |
498 | printk(KERN_INFO "ipcomp init: can't add protocol\n"); | |
499 | xfrm_unregister_type(&ipcomp_type, AF_INET); | |
500 | return -EAGAIN; | |
501 | } | |
502 | return 0; | |
503 | } | |
504 | ||
505 | static void __exit ipcomp4_fini(void) | |
506 | { | |
507 | if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) | |
508 | printk(KERN_INFO "ip ipcomp close: can't remove protocol\n"); | |
509 | if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0) | |
510 | printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n"); | |
511 | } | |
512 | ||
513 | module_init(ipcomp4_init); | |
514 | module_exit(ipcomp4_fini); | |
515 | ||
516 | MODULE_LICENSE("GPL"); | |
517 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173"); | |
518 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); | |
519 |