Linux 2.6.25.20
[linux/fpc-iii.git] / net / ipv6 / ipcomp6.c
blobe3dcfa2f436bade207d6b03711868cd30f5531bf
1 /*
2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
4 * Copyright (C)2003 USAGI/WIDE Project
6 * Author Mitsuru KANDA <mk@linux-ipv6.org>
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.
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.
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
23 * [Memo]
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.
29 * Inbound:
30 * The decompression of IP datagram MUST be done after the reassembly,
31 * AH/ESP processing.
33 #include <linux/module.h>
34 #include <net/ip.h>
35 #include <net/xfrm.h>
36 #include <net/ipcomp.h>
37 #include <asm/semaphore.h>
38 #include <linux/crypto.h>
39 #include <linux/err.h>
40 #include <linux/pfkeyv2.h>
41 #include <linux/random.h>
42 #include <linux/percpu.h>
43 #include <linux/smp.h>
44 #include <linux/list.h>
45 #include <linux/vmalloc.h>
46 #include <linux/rtnetlink.h>
47 #include <net/icmp.h>
48 #include <net/ipv6.h>
49 #include <net/protocol.h>
50 #include <linux/ipv6.h>
51 #include <linux/icmpv6.h>
52 #include <linux/mutex.h>
54 struct ipcomp6_tfms {
55 struct list_head list;
56 struct crypto_comp **tfms;
57 int users;
60 static DEFINE_MUTEX(ipcomp6_resource_mutex);
61 static void **ipcomp6_scratches;
62 static int ipcomp6_scratch_users;
63 static LIST_HEAD(ipcomp6_tfms_list);
65 static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
67 int nexthdr;
68 int err = -ENOMEM;
69 struct ip_comp_hdr *ipch;
70 int plen, dlen;
71 struct ipcomp_data *ipcd = x->data;
72 u8 *start, *scratch;
73 struct crypto_comp *tfm;
74 int cpu;
76 if (skb_linearize_cow(skb))
77 goto out;
79 skb->ip_summed = CHECKSUM_NONE;
81 /* Remove ipcomp header and decompress original payload */
82 ipch = (void *)skb->data;
83 nexthdr = ipch->nexthdr;
85 skb->transport_header = skb->network_header + sizeof(*ipch);
86 __skb_pull(skb, sizeof(*ipch));
88 /* decompression */
89 plen = skb->len;
90 dlen = IPCOMP_SCRATCH_SIZE;
91 start = skb->data;
93 cpu = get_cpu();
94 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
95 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
97 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
98 if (err)
99 goto out_put_cpu;
101 if (dlen < (plen + sizeof(*ipch))) {
102 err = -EINVAL;
103 goto out_put_cpu;
106 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
107 if (err) {
108 goto out_put_cpu;
111 skb->truesize += dlen - plen;
112 __skb_put(skb, dlen - plen);
113 skb_copy_to_linear_data(skb, scratch, dlen);
114 err = nexthdr;
116 out_put_cpu:
117 put_cpu();
118 out:
119 return err;
122 static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
124 int err;
125 struct ip_comp_hdr *ipch;
126 struct ipcomp_data *ipcd = x->data;
127 int plen, dlen;
128 u8 *start, *scratch;
129 struct crypto_comp *tfm;
130 int cpu;
132 /* check whether datagram len is larger than threshold */
133 if (skb->len < ipcd->threshold) {
134 goto out_ok;
137 if (skb_linearize_cow(skb))
138 goto out_ok;
140 /* compression */
141 plen = skb->len;
142 dlen = IPCOMP_SCRATCH_SIZE;
143 start = skb->data;
145 cpu = get_cpu();
146 scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
147 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
149 local_bh_disable();
150 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
151 local_bh_enable();
152 if (err || (dlen + sizeof(*ipch)) >= plen) {
153 put_cpu();
154 goto out_ok;
156 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
157 put_cpu();
158 pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
160 /* insert ipcomp header and replace datagram */
161 ipch = ip_comp_hdr(skb);
162 ipch->nexthdr = *skb_mac_header(skb);
163 ipch->flags = 0;
164 ipch->cpi = htons((u16 )ntohl(x->id.spi));
165 *skb_mac_header(skb) = IPPROTO_COMP;
167 out_ok:
168 skb_push(skb, -skb_network_offset(skb));
170 return 0;
173 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
174 int type, int code, int offset, __be32 info)
176 __be32 spi;
177 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
178 struct ip_comp_hdr *ipcomph =
179 (struct ip_comp_hdr *)(skb->data + offset);
180 struct xfrm_state *x;
182 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
183 return;
185 spi = htonl(ntohs(ipcomph->cpi));
186 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
187 if (!x)
188 return;
190 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
191 spi, NIP6(iph->daddr));
192 xfrm_state_put(x);
195 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
197 struct xfrm_state *t = NULL;
199 t = xfrm_state_alloc();
200 if (!t)
201 goto out;
203 t->id.proto = IPPROTO_IPV6;
204 t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
205 if (!t->id.spi)
206 goto error;
208 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
209 memcpy(&t->sel, &x->sel, sizeof(t->sel));
210 t->props.family = AF_INET6;
211 t->props.mode = x->props.mode;
212 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
214 if (xfrm_init_state(t))
215 goto error;
217 atomic_set(&t->tunnel_users, 1);
219 out:
220 return t;
222 error:
223 t->km.state = XFRM_STATE_DEAD;
224 xfrm_state_put(t);
225 t = NULL;
226 goto out;
229 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
231 int err = 0;
232 struct xfrm_state *t = NULL;
233 __be32 spi;
235 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
236 if (spi)
237 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
238 spi, IPPROTO_IPV6, AF_INET6);
239 if (!t) {
240 t = ipcomp6_tunnel_create(x);
241 if (!t) {
242 err = -EINVAL;
243 goto out;
245 xfrm_state_insert(t);
246 xfrm_state_hold(t);
248 x->tunnel = t;
249 atomic_inc(&t->tunnel_users);
251 out:
252 return err;
255 static void ipcomp6_free_scratches(void)
257 int i;
258 void **scratches;
260 if (--ipcomp6_scratch_users)
261 return;
263 scratches = ipcomp6_scratches;
264 if (!scratches)
265 return;
267 for_each_possible_cpu(i) {
268 void *scratch = *per_cpu_ptr(scratches, i);
270 vfree(scratch);
273 free_percpu(scratches);
276 static void **ipcomp6_alloc_scratches(void)
278 int i;
279 void **scratches;
281 if (ipcomp6_scratch_users++)
282 return ipcomp6_scratches;
284 scratches = alloc_percpu(void *);
285 if (!scratches)
286 return NULL;
288 ipcomp6_scratches = scratches;
290 for_each_possible_cpu(i) {
291 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
292 if (!scratch)
293 return NULL;
294 *per_cpu_ptr(scratches, i) = scratch;
297 return scratches;
300 static void ipcomp6_free_tfms(struct crypto_comp **tfms)
302 struct ipcomp6_tfms *pos;
303 int cpu;
305 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
306 if (pos->tfms == tfms)
307 break;
310 BUG_TRAP(pos);
312 if (--pos->users)
313 return;
315 list_del(&pos->list);
316 kfree(pos);
318 if (!tfms)
319 return;
321 for_each_possible_cpu(cpu) {
322 struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
323 crypto_free_comp(tfm);
325 free_percpu(tfms);
328 static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name)
330 struct ipcomp6_tfms *pos;
331 struct crypto_comp **tfms;
332 int cpu;
334 /* This can be any valid CPU ID so we don't need locking. */
335 cpu = raw_smp_processor_id();
337 list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
338 struct crypto_comp *tfm;
340 tfms = pos->tfms;
341 tfm = *per_cpu_ptr(tfms, cpu);
343 if (!strcmp(crypto_comp_name(tfm), alg_name)) {
344 pos->users++;
345 return tfms;
349 pos = kmalloc(sizeof(*pos), GFP_KERNEL);
350 if (!pos)
351 return NULL;
353 pos->users = 1;
354 INIT_LIST_HEAD(&pos->list);
355 list_add(&pos->list, &ipcomp6_tfms_list);
357 pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
358 if (!tfms)
359 goto error;
361 for_each_possible_cpu(cpu) {
362 struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
363 CRYPTO_ALG_ASYNC);
364 if (IS_ERR(tfm))
365 goto error;
366 *per_cpu_ptr(tfms, cpu) = tfm;
369 return tfms;
371 error:
372 ipcomp6_free_tfms(tfms);
373 return NULL;
376 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
378 if (ipcd->tfms)
379 ipcomp6_free_tfms(ipcd->tfms);
380 ipcomp6_free_scratches();
383 static void ipcomp6_destroy(struct xfrm_state *x)
385 struct ipcomp_data *ipcd = x->data;
386 if (!ipcd)
387 return;
388 xfrm_state_delete_tunnel(x);
389 mutex_lock(&ipcomp6_resource_mutex);
390 ipcomp6_free_data(ipcd);
391 mutex_unlock(&ipcomp6_resource_mutex);
392 kfree(ipcd);
394 xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
397 static int ipcomp6_init_state(struct xfrm_state *x)
399 int err;
400 struct ipcomp_data *ipcd;
401 struct xfrm_algo_desc *calg_desc;
403 err = -EINVAL;
404 if (!x->calg)
405 goto out;
407 if (x->encap)
408 goto out;
410 x->props.header_len = 0;
411 switch (x->props.mode) {
412 case XFRM_MODE_TRANSPORT:
413 break;
414 case XFRM_MODE_TUNNEL:
415 x->props.header_len += sizeof(struct ipv6hdr);
416 break;
417 default:
418 goto out;
421 err = -ENOMEM;
422 ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
423 if (!ipcd)
424 goto out;
426 mutex_lock(&ipcomp6_resource_mutex);
427 if (!ipcomp6_alloc_scratches())
428 goto error;
430 ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
431 if (!ipcd->tfms)
432 goto error;
433 mutex_unlock(&ipcomp6_resource_mutex);
435 if (x->props.mode == XFRM_MODE_TUNNEL) {
436 err = ipcomp6_tunnel_attach(x);
437 if (err)
438 goto error_tunnel;
441 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
442 BUG_ON(!calg_desc);
443 ipcd->threshold = calg_desc->uinfo.comp.threshold;
444 x->data = ipcd;
445 err = 0;
446 out:
447 return err;
448 error_tunnel:
449 mutex_lock(&ipcomp6_resource_mutex);
450 error:
451 ipcomp6_free_data(ipcd);
452 mutex_unlock(&ipcomp6_resource_mutex);
453 kfree(ipcd);
455 goto out;
458 static const struct xfrm_type ipcomp6_type =
460 .description = "IPCOMP6",
461 .owner = THIS_MODULE,
462 .proto = IPPROTO_COMP,
463 .init_state = ipcomp6_init_state,
464 .destructor = ipcomp6_destroy,
465 .input = ipcomp6_input,
466 .output = ipcomp6_output,
467 .hdr_offset = xfrm6_find_1stfragopt,
470 static struct inet6_protocol ipcomp6_protocol =
472 .handler = xfrm6_rcv,
473 .err_handler = ipcomp6_err,
474 .flags = INET6_PROTO_NOPOLICY,
477 static int __init ipcomp6_init(void)
479 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
480 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
481 return -EAGAIN;
483 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
484 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
485 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
486 return -EAGAIN;
488 return 0;
491 static void __exit ipcomp6_fini(void)
493 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
494 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
495 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
496 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
499 module_init(ipcomp6_init);
500 module_exit(ipcomp6_fini);
501 MODULE_LICENSE("GPL");
502 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
503 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
505 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);