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 | */ | |
33 | #include <linux/config.h> | |
34 | #include <linux/module.h> | |
35 | #include <net/ip.h> | |
36 | #include <net/xfrm.h> | |
37 | #include <net/ipcomp.h> | |
38 | #include <asm/scatterlist.h> | |
39 | #include <asm/semaphore.h> | |
40 | #include <linux/crypto.h> | |
41 | #include <linux/pfkeyv2.h> | |
42 | #include <linux/random.h> | |
43 | #include <linux/percpu.h> | |
44 | #include <linux/smp.h> | |
45 | #include <linux/list.h> | |
46 | #include <linux/vmalloc.h> | |
47 | #include <linux/rtnetlink.h> | |
48 | #include <net/icmp.h> | |
49 | #include <net/ipv6.h> | |
14c85021 | 50 | #include <net/protocol.h> |
1da177e4 LT |
51 | #include <linux/ipv6.h> |
52 | #include <linux/icmpv6.h> | |
53 | ||
54 | struct ipcomp6_tfms { | |
55 | struct list_head list; | |
56 | struct crypto_tfm **tfms; | |
57 | int users; | |
58 | }; | |
59 | ||
60 | static DECLARE_MUTEX(ipcomp6_resource_sem); | |
61 | static void **ipcomp6_scratches; | |
62 | static int ipcomp6_scratch_users; | |
63 | static LIST_HEAD(ipcomp6_tfms_list); | |
64 | ||
65 | static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb) | |
66 | { | |
67 | int err = 0; | |
68 | u8 nexthdr = 0; | |
69 | int hdr_len = skb->h.raw - skb->nh.raw; | |
70 | unsigned char *tmp_hdr = NULL; | |
71 | struct ipv6hdr *iph; | |
72 | int plen, dlen; | |
73 | struct ipcomp_data *ipcd = x->data; | |
74 | u8 *start, *scratch; | |
75 | struct crypto_tfm *tfm; | |
76 | int cpu; | |
77 | ||
78 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && | |
79 | skb_linearize(skb, GFP_ATOMIC) != 0) { | |
80 | err = -ENOMEM; | |
81 | goto out; | |
82 | } | |
83 | ||
84 | skb->ip_summed = CHECKSUM_NONE; | |
85 | ||
86 | /* Remove ipcomp header and decompress original payload */ | |
87 | iph = skb->nh.ipv6h; | |
88 | tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC); | |
89 | if (!tmp_hdr) | |
90 | goto out; | |
91 | memcpy(tmp_hdr, iph, hdr_len); | |
92 | nexthdr = *(u8 *)skb->data; | |
93 | skb_pull(skb, sizeof(struct ipv6_comp_hdr)); | |
94 | skb->nh.raw += sizeof(struct ipv6_comp_hdr); | |
95 | memcpy(skb->nh.raw, tmp_hdr, hdr_len); | |
96 | iph = skb->nh.ipv6h; | |
97 | iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr)); | |
98 | skb->h.raw = skb->data; | |
99 | ||
100 | /* decompression */ | |
101 | plen = skb->len; | |
102 | dlen = IPCOMP_SCRATCH_SIZE; | |
103 | start = skb->data; | |
104 | ||
105 | cpu = get_cpu(); | |
106 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
107 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
108 | ||
109 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
110 | if (err) { | |
111 | err = -EINVAL; | |
112 | goto out_put_cpu; | |
113 | } | |
114 | ||
115 | if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) { | |
116 | err = -EINVAL; | |
117 | goto out_put_cpu; | |
118 | } | |
119 | ||
120 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
121 | if (err) { | |
122 | goto out_put_cpu; | |
123 | } | |
124 | ||
125 | skb_put(skb, dlen - plen); | |
126 | memcpy(skb->data, scratch, dlen); | |
127 | ||
128 | iph = skb->nh.ipv6h; | |
129 | iph->payload_len = htons(skb->len); | |
130 | ||
131 | out_put_cpu: | |
132 | put_cpu(); | |
133 | out: | |
a51482bd | 134 | kfree(tmp_hdr); |
1da177e4 LT |
135 | if (err) |
136 | goto error_out; | |
137 | return nexthdr; | |
138 | error_out: | |
139 | return err; | |
140 | } | |
141 | ||
142 | static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb) | |
143 | { | |
144 | int err; | |
145 | struct ipv6hdr *top_iph; | |
146 | int hdr_len; | |
147 | struct ipv6_comp_hdr *ipch; | |
148 | struct ipcomp_data *ipcd = x->data; | |
149 | int plen, dlen; | |
150 | u8 *start, *scratch; | |
151 | struct crypto_tfm *tfm; | |
152 | int cpu; | |
153 | ||
154 | hdr_len = skb->h.raw - skb->data; | |
155 | ||
156 | /* check whether datagram len is larger than threshold */ | |
157 | if ((skb->len - hdr_len) < ipcd->threshold) { | |
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 | /* compression */ | |
167 | plen = skb->len - hdr_len; | |
168 | dlen = IPCOMP_SCRATCH_SIZE; | |
169 | start = skb->h.raw; | |
170 | ||
171 | cpu = get_cpu(); | |
172 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
173 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
174 | ||
175 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); | |
176 | if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) { | |
177 | put_cpu(); | |
178 | goto out_ok; | |
179 | } | |
180 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); | |
181 | put_cpu(); | |
182 | pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr)); | |
183 | ||
184 | /* insert ipcomp header and replace datagram */ | |
185 | top_iph = (struct ipv6hdr *)skb->data; | |
186 | ||
187 | top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); | |
188 | ||
189 | ipch = (struct ipv6_comp_hdr *)start; | |
190 | ipch->nexthdr = *skb->nh.raw; | |
191 | ipch->flags = 0; | |
192 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); | |
193 | *skb->nh.raw = IPPROTO_COMP; | |
194 | ||
195 | out_ok: | |
196 | return 0; | |
197 | } | |
198 | ||
199 | static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
200 | int type, int code, int offset, __u32 info) | |
201 | { | |
202 | u32 spi; | |
203 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; | |
204 | struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset); | |
205 | struct xfrm_state *x; | |
206 | ||
207 | if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) | |
208 | return; | |
209 | ||
210 | spi = ntohl(ntohs(ipcomph->cpi)); | |
211 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6); | |
212 | if (!x) | |
213 | return; | |
214 | ||
46b86a2d | 215 | printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n", |
1da177e4 LT |
216 | spi, NIP6(iph->daddr)); |
217 | xfrm_state_put(x); | |
218 | } | |
219 | ||
220 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) | |
221 | { | |
222 | struct xfrm_state *t = NULL; | |
223 | ||
224 | t = xfrm_state_alloc(); | |
225 | if (!t) | |
226 | goto out; | |
227 | ||
228 | t->id.proto = IPPROTO_IPV6; | |
229 | t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr); | |
230 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); | |
231 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
232 | t->props.family = AF_INET6; | |
233 | t->props.mode = 1; | |
234 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); | |
235 | ||
72cb6962 | 236 | if (xfrm_init_state(t)) |
1da177e4 LT |
237 | goto error; |
238 | ||
1da177e4 LT |
239 | atomic_set(&t->tunnel_users, 1); |
240 | ||
241 | out: | |
242 | return t; | |
243 | ||
244 | error: | |
245 | xfrm_state_put(t); | |
246 | goto out; | |
247 | } | |
248 | ||
249 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) | |
250 | { | |
251 | int err = 0; | |
252 | struct xfrm_state *t = NULL; | |
253 | u32 spi; | |
254 | ||
255 | spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); | |
256 | if (spi) | |
257 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, | |
258 | spi, IPPROTO_IPV6, AF_INET6); | |
259 | if (!t) { | |
260 | t = ipcomp6_tunnel_create(x); | |
261 | if (!t) { | |
262 | err = -EINVAL; | |
263 | goto out; | |
264 | } | |
265 | xfrm_state_insert(t); | |
266 | xfrm_state_hold(t); | |
267 | } | |
268 | x->tunnel = t; | |
269 | atomic_inc(&t->tunnel_users); | |
270 | ||
271 | out: | |
272 | return err; | |
273 | } | |
274 | ||
275 | static void ipcomp6_free_scratches(void) | |
276 | { | |
277 | int i; | |
278 | void **scratches; | |
279 | ||
280 | if (--ipcomp6_scratch_users) | |
281 | return; | |
282 | ||
283 | scratches = ipcomp6_scratches; | |
284 | if (!scratches) | |
285 | return; | |
286 | ||
287 | for_each_cpu(i) { | |
288 | void *scratch = *per_cpu_ptr(scratches, i); | |
2b191bef JJ |
289 | |
290 | vfree(scratch); | |
1da177e4 LT |
291 | } |
292 | ||
293 | free_percpu(scratches); | |
294 | } | |
295 | ||
296 | static void **ipcomp6_alloc_scratches(void) | |
297 | { | |
298 | int i; | |
299 | void **scratches; | |
300 | ||
301 | if (ipcomp6_scratch_users++) | |
302 | return ipcomp6_scratches; | |
303 | ||
304 | scratches = alloc_percpu(void *); | |
305 | if (!scratches) | |
306 | return NULL; | |
307 | ||
308 | ipcomp6_scratches = scratches; | |
309 | ||
310 | for_each_cpu(i) { | |
311 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); | |
312 | if (!scratch) | |
313 | return NULL; | |
314 | *per_cpu_ptr(scratches, i) = scratch; | |
315 | } | |
316 | ||
317 | return scratches; | |
318 | } | |
319 | ||
320 | static void ipcomp6_free_tfms(struct crypto_tfm **tfms) | |
321 | { | |
322 | struct ipcomp6_tfms *pos; | |
323 | int cpu; | |
324 | ||
325 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
326 | if (pos->tfms == tfms) | |
327 | break; | |
328 | } | |
329 | ||
330 | BUG_TRAP(pos); | |
331 | ||
332 | if (--pos->users) | |
333 | return; | |
334 | ||
335 | list_del(&pos->list); | |
336 | kfree(pos); | |
337 | ||
338 | if (!tfms) | |
339 | return; | |
340 | ||
341 | for_each_cpu(cpu) { | |
342 | struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu); | |
573dbd95 | 343 | crypto_free_tfm(tfm); |
1da177e4 LT |
344 | } |
345 | free_percpu(tfms); | |
346 | } | |
347 | ||
348 | static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name) | |
349 | { | |
350 | struct ipcomp6_tfms *pos; | |
351 | struct crypto_tfm **tfms; | |
352 | int cpu; | |
353 | ||
354 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 355 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
356 | |
357 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
358 | struct crypto_tfm *tfm; | |
359 | ||
360 | tfms = pos->tfms; | |
361 | tfm = *per_cpu_ptr(tfms, cpu); | |
362 | ||
363 | if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) { | |
364 | pos->users++; | |
365 | return tfms; | |
366 | } | |
367 | } | |
368 | ||
369 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
370 | if (!pos) | |
371 | return NULL; | |
372 | ||
373 | pos->users = 1; | |
374 | INIT_LIST_HEAD(&pos->list); | |
375 | list_add(&pos->list, &ipcomp6_tfms_list); | |
376 | ||
377 | pos->tfms = tfms = alloc_percpu(struct crypto_tfm *); | |
378 | if (!tfms) | |
379 | goto error; | |
380 | ||
381 | for_each_cpu(cpu) { | |
382 | struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0); | |
383 | if (!tfm) | |
384 | goto error; | |
385 | *per_cpu_ptr(tfms, cpu) = tfm; | |
386 | } | |
387 | ||
388 | return tfms; | |
389 | ||
390 | error: | |
391 | ipcomp6_free_tfms(tfms); | |
392 | return NULL; | |
393 | } | |
394 | ||
395 | static void ipcomp6_free_data(struct ipcomp_data *ipcd) | |
396 | { | |
397 | if (ipcd->tfms) | |
398 | ipcomp6_free_tfms(ipcd->tfms); | |
399 | ipcomp6_free_scratches(); | |
400 | } | |
401 | ||
402 | static void ipcomp6_destroy(struct xfrm_state *x) | |
403 | { | |
404 | struct ipcomp_data *ipcd = x->data; | |
405 | if (!ipcd) | |
406 | return; | |
407 | xfrm_state_delete_tunnel(x); | |
408 | down(&ipcomp6_resource_sem); | |
409 | ipcomp6_free_data(ipcd); | |
410 | up(&ipcomp6_resource_sem); | |
411 | kfree(ipcd); | |
412 | ||
413 | xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr); | |
414 | } | |
415 | ||
72cb6962 | 416 | static int ipcomp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
417 | { |
418 | int err; | |
419 | struct ipcomp_data *ipcd; | |
420 | struct xfrm_algo_desc *calg_desc; | |
421 | ||
422 | err = -EINVAL; | |
423 | if (!x->calg) | |
424 | goto out; | |
425 | ||
426 | if (x->encap) | |
427 | goto out; | |
428 | ||
429 | err = -ENOMEM; | |
430 | ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL); | |
431 | if (!ipcd) | |
432 | goto out; | |
433 | ||
434 | memset(ipcd, 0, sizeof(*ipcd)); | |
435 | x->props.header_len = 0; | |
436 | if (x->props.mode) | |
437 | x->props.header_len += sizeof(struct ipv6hdr); | |
438 | ||
439 | down(&ipcomp6_resource_sem); | |
440 | if (!ipcomp6_alloc_scratches()) | |
441 | goto error; | |
442 | ||
443 | ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name); | |
444 | if (!ipcd->tfms) | |
445 | goto error; | |
446 | up(&ipcomp6_resource_sem); | |
447 | ||
448 | if (x->props.mode) { | |
449 | err = ipcomp6_tunnel_attach(x); | |
450 | if (err) | |
451 | goto error_tunnel; | |
452 | } | |
453 | ||
454 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
455 | BUG_ON(!calg_desc); | |
456 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
457 | x->data = ipcd; | |
458 | err = 0; | |
459 | out: | |
460 | return err; | |
461 | error_tunnel: | |
462 | down(&ipcomp6_resource_sem); | |
463 | error: | |
464 | ipcomp6_free_data(ipcd); | |
465 | up(&ipcomp6_resource_sem); | |
466 | kfree(ipcd); | |
467 | ||
468 | goto out; | |
469 | } | |
470 | ||
471 | static struct xfrm_type ipcomp6_type = | |
472 | { | |
473 | .description = "IPCOMP6", | |
474 | .owner = THIS_MODULE, | |
475 | .proto = IPPROTO_COMP, | |
476 | .init_state = ipcomp6_init_state, | |
477 | .destructor = ipcomp6_destroy, | |
478 | .input = ipcomp6_input, | |
479 | .output = ipcomp6_output, | |
480 | }; | |
481 | ||
482 | static struct inet6_protocol ipcomp6_protocol = | |
483 | { | |
484 | .handler = xfrm6_rcv, | |
485 | .err_handler = ipcomp6_err, | |
486 | .flags = INET6_PROTO_NOPOLICY, | |
487 | }; | |
488 | ||
489 | static int __init ipcomp6_init(void) | |
490 | { | |
491 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { | |
492 | printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); | |
493 | return -EAGAIN; | |
494 | } | |
495 | if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { | |
496 | printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); | |
497 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
498 | return -EAGAIN; | |
499 | } | |
500 | return 0; | |
501 | } | |
502 | ||
503 | static void __exit ipcomp6_fini(void) | |
504 | { | |
505 | if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) | |
506 | printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); | |
507 | if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) | |
508 | printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); | |
509 | } | |
510 | ||
511 | module_init(ipcomp6_init); | |
512 | module_exit(ipcomp6_fini); | |
513 | MODULE_LICENSE("GPL"); | |
514 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); | |
515 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); | |
516 | ||
517 |