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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> | |
50 | #include <linux/ipv6.h> | |
51 | #include <linux/icmpv6.h> | |
52 | ||
53 | struct ipcomp6_tfms { | |
54 | struct list_head list; | |
55 | struct crypto_tfm **tfms; | |
56 | int users; | |
57 | }; | |
58 | ||
59 | static DECLARE_MUTEX(ipcomp6_resource_sem); | |
60 | static void **ipcomp6_scratches; | |
61 | static int ipcomp6_scratch_users; | |
62 | static LIST_HEAD(ipcomp6_tfms_list); | |
63 | ||
64 | static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb) | |
65 | { | |
66 | int err = 0; | |
67 | u8 nexthdr = 0; | |
68 | int hdr_len = skb->h.raw - skb->nh.raw; | |
69 | unsigned char *tmp_hdr = NULL; | |
70 | struct ipv6hdr *iph; | |
71 | int plen, dlen; | |
72 | struct ipcomp_data *ipcd = x->data; | |
73 | u8 *start, *scratch; | |
74 | struct crypto_tfm *tfm; | |
75 | int cpu; | |
76 | ||
77 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && | |
78 | skb_linearize(skb, GFP_ATOMIC) != 0) { | |
79 | err = -ENOMEM; | |
80 | goto out; | |
81 | } | |
82 | ||
83 | skb->ip_summed = CHECKSUM_NONE; | |
84 | ||
85 | /* Remove ipcomp header and decompress original payload */ | |
86 | iph = skb->nh.ipv6h; | |
87 | tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC); | |
88 | if (!tmp_hdr) | |
89 | goto out; | |
90 | memcpy(tmp_hdr, iph, hdr_len); | |
91 | nexthdr = *(u8 *)skb->data; | |
92 | skb_pull(skb, sizeof(struct ipv6_comp_hdr)); | |
93 | skb->nh.raw += sizeof(struct ipv6_comp_hdr); | |
94 | memcpy(skb->nh.raw, tmp_hdr, hdr_len); | |
95 | iph = skb->nh.ipv6h; | |
96 | iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr)); | |
97 | skb->h.raw = skb->data; | |
98 | ||
99 | /* decompression */ | |
100 | plen = skb->len; | |
101 | dlen = IPCOMP_SCRATCH_SIZE; | |
102 | start = skb->data; | |
103 | ||
104 | cpu = get_cpu(); | |
105 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); | |
106 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); | |
107 | ||
108 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); | |
109 | if (err) { | |
110 | err = -EINVAL; | |
111 | goto out_put_cpu; | |
112 | } | |
113 | ||
114 | if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) { | |
115 | err = -EINVAL; | |
116 | goto out_put_cpu; | |
117 | } | |
118 | ||
119 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); | |
120 | if (err) { | |
121 | goto out_put_cpu; | |
122 | } | |
123 | ||
124 | skb_put(skb, dlen - plen); | |
125 | memcpy(skb->data, scratch, dlen); | |
126 | ||
127 | iph = skb->nh.ipv6h; | |
128 | iph->payload_len = htons(skb->len); | |
129 | ||
130 | out_put_cpu: | |
131 | put_cpu(); | |
132 | out: | |
133 | if (tmp_hdr) | |
134 | kfree(tmp_hdr); | |
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 | ||
215 | printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" | |
216 | "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n", | |
217 | spi, NIP6(iph->daddr)); | |
218 | xfrm_state_put(x); | |
219 | } | |
220 | ||
221 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) | |
222 | { | |
223 | struct xfrm_state *t = NULL; | |
224 | ||
225 | t = xfrm_state_alloc(); | |
226 | if (!t) | |
227 | goto out; | |
228 | ||
229 | t->id.proto = IPPROTO_IPV6; | |
230 | t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr); | |
231 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); | |
232 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
233 | t->props.family = AF_INET6; | |
234 | t->props.mode = 1; | |
235 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); | |
236 | ||
72cb6962 | 237 | if (xfrm_init_state(t)) |
1da177e4 LT |
238 | goto error; |
239 | ||
1da177e4 LT |
240 | atomic_set(&t->tunnel_users, 1); |
241 | ||
242 | out: | |
243 | return t; | |
244 | ||
245 | error: | |
246 | xfrm_state_put(t); | |
247 | goto out; | |
248 | } | |
249 | ||
250 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) | |
251 | { | |
252 | int err = 0; | |
253 | struct xfrm_state *t = NULL; | |
254 | u32 spi; | |
255 | ||
256 | spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); | |
257 | if (spi) | |
258 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, | |
259 | spi, IPPROTO_IPV6, AF_INET6); | |
260 | if (!t) { | |
261 | t = ipcomp6_tunnel_create(x); | |
262 | if (!t) { | |
263 | err = -EINVAL; | |
264 | goto out; | |
265 | } | |
266 | xfrm_state_insert(t); | |
267 | xfrm_state_hold(t); | |
268 | } | |
269 | x->tunnel = t; | |
270 | atomic_inc(&t->tunnel_users); | |
271 | ||
272 | out: | |
273 | return err; | |
274 | } | |
275 | ||
276 | static void ipcomp6_free_scratches(void) | |
277 | { | |
278 | int i; | |
279 | void **scratches; | |
280 | ||
281 | if (--ipcomp6_scratch_users) | |
282 | return; | |
283 | ||
284 | scratches = ipcomp6_scratches; | |
285 | if (!scratches) | |
286 | return; | |
287 | ||
288 | for_each_cpu(i) { | |
289 | void *scratch = *per_cpu_ptr(scratches, i); | |
290 | if (scratch) | |
291 | vfree(scratch); | |
292 | } | |
293 | ||
294 | free_percpu(scratches); | |
295 | } | |
296 | ||
297 | static void **ipcomp6_alloc_scratches(void) | |
298 | { | |
299 | int i; | |
300 | void **scratches; | |
301 | ||
302 | if (ipcomp6_scratch_users++) | |
303 | return ipcomp6_scratches; | |
304 | ||
305 | scratches = alloc_percpu(void *); | |
306 | if (!scratches) | |
307 | return NULL; | |
308 | ||
309 | ipcomp6_scratches = scratches; | |
310 | ||
311 | for_each_cpu(i) { | |
312 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); | |
313 | if (!scratch) | |
314 | return NULL; | |
315 | *per_cpu_ptr(scratches, i) = scratch; | |
316 | } | |
317 | ||
318 | return scratches; | |
319 | } | |
320 | ||
321 | static void ipcomp6_free_tfms(struct crypto_tfm **tfms) | |
322 | { | |
323 | struct ipcomp6_tfms *pos; | |
324 | int cpu; | |
325 | ||
326 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
327 | if (pos->tfms == tfms) | |
328 | break; | |
329 | } | |
330 | ||
331 | BUG_TRAP(pos); | |
332 | ||
333 | if (--pos->users) | |
334 | return; | |
335 | ||
336 | list_del(&pos->list); | |
337 | kfree(pos); | |
338 | ||
339 | if (!tfms) | |
340 | return; | |
341 | ||
342 | for_each_cpu(cpu) { | |
343 | struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu); | |
344 | if (tfm) | |
345 | crypto_free_tfm(tfm); | |
346 | } | |
347 | free_percpu(tfms); | |
348 | } | |
349 | ||
350 | static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name) | |
351 | { | |
352 | struct ipcomp6_tfms *pos; | |
353 | struct crypto_tfm **tfms; | |
354 | int cpu; | |
355 | ||
356 | /* This can be any valid CPU ID so we don't need locking. */ | |
6fc8b9e7 | 357 | cpu = raw_smp_processor_id(); |
1da177e4 LT |
358 | |
359 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { | |
360 | struct crypto_tfm *tfm; | |
361 | ||
362 | tfms = pos->tfms; | |
363 | tfm = *per_cpu_ptr(tfms, cpu); | |
364 | ||
365 | if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) { | |
366 | pos->users++; | |
367 | return tfms; | |
368 | } | |
369 | } | |
370 | ||
371 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); | |
372 | if (!pos) | |
373 | return NULL; | |
374 | ||
375 | pos->users = 1; | |
376 | INIT_LIST_HEAD(&pos->list); | |
377 | list_add(&pos->list, &ipcomp6_tfms_list); | |
378 | ||
379 | pos->tfms = tfms = alloc_percpu(struct crypto_tfm *); | |
380 | if (!tfms) | |
381 | goto error; | |
382 | ||
383 | for_each_cpu(cpu) { | |
384 | struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0); | |
385 | if (!tfm) | |
386 | goto error; | |
387 | *per_cpu_ptr(tfms, cpu) = tfm; | |
388 | } | |
389 | ||
390 | return tfms; | |
391 | ||
392 | error: | |
393 | ipcomp6_free_tfms(tfms); | |
394 | return NULL; | |
395 | } | |
396 | ||
397 | static void ipcomp6_free_data(struct ipcomp_data *ipcd) | |
398 | { | |
399 | if (ipcd->tfms) | |
400 | ipcomp6_free_tfms(ipcd->tfms); | |
401 | ipcomp6_free_scratches(); | |
402 | } | |
403 | ||
404 | static void ipcomp6_destroy(struct xfrm_state *x) | |
405 | { | |
406 | struct ipcomp_data *ipcd = x->data; | |
407 | if (!ipcd) | |
408 | return; | |
409 | xfrm_state_delete_tunnel(x); | |
410 | down(&ipcomp6_resource_sem); | |
411 | ipcomp6_free_data(ipcd); | |
412 | up(&ipcomp6_resource_sem); | |
413 | kfree(ipcd); | |
414 | ||
415 | xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr); | |
416 | } | |
417 | ||
72cb6962 | 418 | static int ipcomp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
419 | { |
420 | int err; | |
421 | struct ipcomp_data *ipcd; | |
422 | struct xfrm_algo_desc *calg_desc; | |
423 | ||
424 | err = -EINVAL; | |
425 | if (!x->calg) | |
426 | goto out; | |
427 | ||
428 | if (x->encap) | |
429 | goto out; | |
430 | ||
431 | err = -ENOMEM; | |
432 | ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL); | |
433 | if (!ipcd) | |
434 | goto out; | |
435 | ||
436 | memset(ipcd, 0, sizeof(*ipcd)); | |
437 | x->props.header_len = 0; | |
438 | if (x->props.mode) | |
439 | x->props.header_len += sizeof(struct ipv6hdr); | |
440 | ||
441 | down(&ipcomp6_resource_sem); | |
442 | if (!ipcomp6_alloc_scratches()) | |
443 | goto error; | |
444 | ||
445 | ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name); | |
446 | if (!ipcd->tfms) | |
447 | goto error; | |
448 | up(&ipcomp6_resource_sem); | |
449 | ||
450 | if (x->props.mode) { | |
451 | err = ipcomp6_tunnel_attach(x); | |
452 | if (err) | |
453 | goto error_tunnel; | |
454 | } | |
455 | ||
456 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); | |
457 | BUG_ON(!calg_desc); | |
458 | ipcd->threshold = calg_desc->uinfo.comp.threshold; | |
459 | x->data = ipcd; | |
460 | err = 0; | |
461 | out: | |
462 | return err; | |
463 | error_tunnel: | |
464 | down(&ipcomp6_resource_sem); | |
465 | error: | |
466 | ipcomp6_free_data(ipcd); | |
467 | up(&ipcomp6_resource_sem); | |
468 | kfree(ipcd); | |
469 | ||
470 | goto out; | |
471 | } | |
472 | ||
473 | static struct xfrm_type ipcomp6_type = | |
474 | { | |
475 | .description = "IPCOMP6", | |
476 | .owner = THIS_MODULE, | |
477 | .proto = IPPROTO_COMP, | |
478 | .init_state = ipcomp6_init_state, | |
479 | .destructor = ipcomp6_destroy, | |
480 | .input = ipcomp6_input, | |
481 | .output = ipcomp6_output, | |
482 | }; | |
483 | ||
484 | static struct inet6_protocol ipcomp6_protocol = | |
485 | { | |
486 | .handler = xfrm6_rcv, | |
487 | .err_handler = ipcomp6_err, | |
488 | .flags = INET6_PROTO_NOPOLICY, | |
489 | }; | |
490 | ||
491 | static int __init ipcomp6_init(void) | |
492 | { | |
493 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { | |
494 | printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); | |
495 | return -EAGAIN; | |
496 | } | |
497 | if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { | |
498 | printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); | |
499 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
500 | return -EAGAIN; | |
501 | } | |
502 | return 0; | |
503 | } | |
504 | ||
505 | static void __exit ipcomp6_fini(void) | |
506 | { | |
507 | if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) | |
508 | printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); | |
509 | if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) | |
510 | printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); | |
511 | } | |
512 | ||
513 | module_init(ipcomp6_init); | |
514 | module_exit(ipcomp6_fini); | |
515 | MODULE_LICENSE("GPL"); | |
516 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); | |
517 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); | |
518 | ||
519 |