[NETFILTER]: Clean up Makefile
[linux-2.6] / net / ipv6 / ipcomp6.c
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/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/pfkeyv2.h>
40 #include <linux/random.h>
41 #include <linux/percpu.h>
42 #include <linux/smp.h>
43 #include <linux/list.h>
44 #include <linux/vmalloc.h>
45 #include <linux/rtnetlink.h>
46 #include <net/icmp.h>
47 #include <net/ipv6.h>
48 #include <net/protocol.h>
49 #include <linux/ipv6.h>
50 #include <linux/icmpv6.h>
51 #include <linux/mutex.h>
52
53 struct ipcomp6_tfms {
54         struct list_head list;
55         struct crypto_comp **tfms;
56         int users;
57 };
58
59 static DEFINE_MUTEX(ipcomp6_resource_mutex);
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 sk_buff *skb)
65 {
66         int err = -ENOMEM;
67         struct ip_comp_hdr *ipch;
68         int plen, dlen;
69         struct ipcomp_data *ipcd = x->data;
70         u8 *start, *scratch;
71         struct crypto_comp *tfm;
72         int cpu;
73
74         if (skb_linearize_cow(skb))
75                 goto out;
76
77         skb->ip_summed = CHECKSUM_NONE;
78
79         /* Remove ipcomp header and decompress original payload */
80         ipch = (void *)skb->data;
81         skb->transport_header = skb->network_header + sizeof(*ipch);
82         __skb_pull(skb, sizeof(*ipch));
83
84         /* decompression */
85         plen = skb->len;
86         dlen = IPCOMP_SCRATCH_SIZE;
87         start = skb->data;
88
89         cpu = get_cpu();
90         scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
91         tfm = *per_cpu_ptr(ipcd->tfms, cpu);
92
93         err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
94         if (err)
95                 goto out_put_cpu;
96
97         if (dlen < (plen + sizeof(*ipch))) {
98                 err = -EINVAL;
99                 goto out_put_cpu;
100         }
101
102         err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
103         if (err) {
104                 goto out_put_cpu;
105         }
106
107         skb->truesize += dlen - plen;
108         __skb_put(skb, dlen - plen);
109         skb_copy_to_linear_data(skb, scratch, dlen);
110         err = ipch->nexthdr;
111
112 out_put_cpu:
113         put_cpu();
114 out:
115         return err;
116 }
117
118 static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
119 {
120         int err;
121         struct ip_comp_hdr *ipch;
122         struct ipcomp_data *ipcd = x->data;
123         int plen, dlen;
124         u8 *start, *scratch;
125         struct crypto_comp *tfm;
126         int cpu;
127
128         /* check whether datagram len is larger than threshold */
129         if (skb->len < ipcd->threshold) {
130                 goto out_ok;
131         }
132
133         if (skb_linearize_cow(skb))
134                 goto out_ok;
135
136         /* compression */
137         plen = skb->len;
138         dlen = IPCOMP_SCRATCH_SIZE;
139         start = skb->data;
140
141         cpu = get_cpu();
142         scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
143         tfm = *per_cpu_ptr(ipcd->tfms, cpu);
144
145         err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
146         if (err || (dlen + sizeof(*ipch)) >= plen) {
147                 put_cpu();
148                 goto out_ok;
149         }
150         memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
151         put_cpu();
152         pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
153
154         /* insert ipcomp header and replace datagram */
155         ipch = ip_comp_hdr(skb);
156         ipch->nexthdr = *skb_mac_header(skb);
157         ipch->flags = 0;
158         ipch->cpi = htons((u16 )ntohl(x->id.spi));
159         *skb_mac_header(skb) = IPPROTO_COMP;
160
161 out_ok:
162         skb_push(skb, -skb_network_offset(skb));
163
164         return 0;
165 }
166
167 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
168                                 int type, int code, int offset, __be32 info)
169 {
170         __be32 spi;
171         struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
172         struct ip_comp_hdr *ipcomph =
173                 (struct ip_comp_hdr *)(skb->data + offset);
174         struct xfrm_state *x;
175
176         if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
177                 return;
178
179         spi = htonl(ntohs(ipcomph->cpi));
180         x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
181         if (!x)
182                 return;
183
184         printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
185                         spi, NIP6(iph->daddr));
186         xfrm_state_put(x);
187 }
188
189 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
190 {
191         struct xfrm_state *t = NULL;
192         u8 mode = XFRM_MODE_TUNNEL;
193
194         t = xfrm_state_alloc();
195         if (!t)
196                 goto out;
197
198         t->id.proto = IPPROTO_IPV6;
199         t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
200         if (!t->id.spi)
201                 goto error;
202
203         memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
204         memcpy(&t->sel, &x->sel, sizeof(t->sel));
205         t->props.family = AF_INET6;
206         if (x->props.mode == XFRM_MODE_BEET)
207                 mode = x->props.mode;
208         t->props.mode = mode;
209         memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
210
211         if (xfrm_init_state(t))
212                 goto error;
213
214         atomic_set(&t->tunnel_users, 1);
215
216 out:
217         return t;
218
219 error:
220         t->km.state = XFRM_STATE_DEAD;
221         xfrm_state_put(t);
222         t = NULL;
223         goto out;
224 }
225
226 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
227 {
228         int err = 0;
229         struct xfrm_state *t = NULL;
230         __be32 spi;
231
232         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
233         if (spi)
234                 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
235                                               spi, IPPROTO_IPV6, AF_INET6);
236         if (!t) {
237                 t = ipcomp6_tunnel_create(x);
238                 if (!t) {
239                         err = -EINVAL;
240                         goto out;
241                 }
242                 xfrm_state_insert(t);
243                 xfrm_state_hold(t);
244         }
245         x->tunnel = t;
246         atomic_inc(&t->tunnel_users);
247
248 out:
249         return err;
250 }
251
252 static void ipcomp6_free_scratches(void)
253 {
254         int i;
255         void **scratches;
256
257         if (--ipcomp6_scratch_users)
258                 return;
259
260         scratches = ipcomp6_scratches;
261         if (!scratches)
262                 return;
263
264         for_each_possible_cpu(i) {
265                 void *scratch = *per_cpu_ptr(scratches, i);
266
267                 vfree(scratch);
268         }
269
270         free_percpu(scratches);
271 }
272
273 static void **ipcomp6_alloc_scratches(void)
274 {
275         int i;
276         void **scratches;
277
278         if (ipcomp6_scratch_users++)
279                 return ipcomp6_scratches;
280
281         scratches = alloc_percpu(void *);
282         if (!scratches)
283                 return NULL;
284
285         ipcomp6_scratches = scratches;
286
287         for_each_possible_cpu(i) {
288                 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
289                 if (!scratch)
290                         return NULL;
291                 *per_cpu_ptr(scratches, i) = scratch;
292         }
293
294         return scratches;
295 }
296
297 static void ipcomp6_free_tfms(struct crypto_comp **tfms)
298 {
299         struct ipcomp6_tfms *pos;
300         int cpu;
301
302         list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
303                 if (pos->tfms == tfms)
304                         break;
305         }
306
307         BUG_TRAP(pos);
308
309         if (--pos->users)
310                 return;
311
312         list_del(&pos->list);
313         kfree(pos);
314
315         if (!tfms)
316                 return;
317
318         for_each_possible_cpu(cpu) {
319                 struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
320                 crypto_free_comp(tfm);
321         }
322         free_percpu(tfms);
323 }
324
325 static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name)
326 {
327         struct ipcomp6_tfms *pos;
328         struct crypto_comp **tfms;
329         int cpu;
330
331         /* This can be any valid CPU ID so we don't need locking. */
332         cpu = raw_smp_processor_id();
333
334         list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
335                 struct crypto_comp *tfm;
336
337                 tfms = pos->tfms;
338                 tfm = *per_cpu_ptr(tfms, cpu);
339
340                 if (!strcmp(crypto_comp_name(tfm), alg_name)) {
341                         pos->users++;
342                         return tfms;
343                 }
344         }
345
346         pos = kmalloc(sizeof(*pos), GFP_KERNEL);
347         if (!pos)
348                 return NULL;
349
350         pos->users = 1;
351         INIT_LIST_HEAD(&pos->list);
352         list_add(&pos->list, &ipcomp6_tfms_list);
353
354         pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
355         if (!tfms)
356                 goto error;
357
358         for_each_possible_cpu(cpu) {
359                 struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
360                                                             CRYPTO_ALG_ASYNC);
361                 if (!tfm)
362                         goto error;
363                 *per_cpu_ptr(tfms, cpu) = tfm;
364         }
365
366         return tfms;
367
368 error:
369         ipcomp6_free_tfms(tfms);
370         return NULL;
371 }
372
373 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
374 {
375         if (ipcd->tfms)
376                 ipcomp6_free_tfms(ipcd->tfms);
377         ipcomp6_free_scratches();
378 }
379
380 static void ipcomp6_destroy(struct xfrm_state *x)
381 {
382         struct ipcomp_data *ipcd = x->data;
383         if (!ipcd)
384                 return;
385         xfrm_state_delete_tunnel(x);
386         mutex_lock(&ipcomp6_resource_mutex);
387         ipcomp6_free_data(ipcd);
388         mutex_unlock(&ipcomp6_resource_mutex);
389         kfree(ipcd);
390
391         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
392 }
393
394 static int ipcomp6_init_state(struct xfrm_state *x)
395 {
396         int err;
397         struct ipcomp_data *ipcd;
398         struct xfrm_algo_desc *calg_desc;
399
400         err = -EINVAL;
401         if (!x->calg)
402                 goto out;
403
404         if (x->encap)
405                 goto out;
406
407         err = -ENOMEM;
408         ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
409         if (!ipcd)
410                 goto out;
411
412         x->props.header_len = 0;
413         switch (x->props.mode) {
414         case XFRM_MODE_BEET:
415         case XFRM_MODE_TRANSPORT:
416                 break;
417         case XFRM_MODE_TUNNEL:
418                 x->props.header_len += sizeof(struct ipv6hdr);
419         default:
420                 goto error;
421         }
422
423         mutex_lock(&ipcomp6_resource_mutex);
424         if (!ipcomp6_alloc_scratches())
425                 goto error;
426
427         ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
428         if (!ipcd->tfms)
429                 goto error;
430         mutex_unlock(&ipcomp6_resource_mutex);
431
432         if (x->props.mode == XFRM_MODE_TUNNEL) {
433                 err = ipcomp6_tunnel_attach(x);
434                 if (err)
435                         goto error_tunnel;
436         }
437
438         calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
439         BUG_ON(!calg_desc);
440         ipcd->threshold = calg_desc->uinfo.comp.threshold;
441         x->data = ipcd;
442         err = 0;
443 out:
444         return err;
445 error_tunnel:
446         mutex_lock(&ipcomp6_resource_mutex);
447 error:
448         ipcomp6_free_data(ipcd);
449         mutex_unlock(&ipcomp6_resource_mutex);
450         kfree(ipcd);
451
452         goto out;
453 }
454
455 static struct xfrm_type ipcomp6_type =
456 {
457         .description    = "IPCOMP6",
458         .owner          = THIS_MODULE,
459         .proto          = IPPROTO_COMP,
460         .init_state     = ipcomp6_init_state,
461         .destructor     = ipcomp6_destroy,
462         .input          = ipcomp6_input,
463         .output         = ipcomp6_output,
464         .hdr_offset     = xfrm6_find_1stfragopt,
465 };
466
467 static struct inet6_protocol ipcomp6_protocol =
468 {
469         .handler        = xfrm6_rcv,
470         .err_handler    = ipcomp6_err,
471         .flags          = INET6_PROTO_NOPOLICY,
472 };
473
474 static int __init ipcomp6_init(void)
475 {
476         if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
477                 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
478                 return -EAGAIN;
479         }
480         if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
481                 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
482                 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
483                 return -EAGAIN;
484         }
485         return 0;
486 }
487
488 static void __exit ipcomp6_fini(void)
489 {
490         if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
491                 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
492         if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
493                 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
494 }
495
496 module_init(ipcomp6_init);
497 module_exit(ipcomp6_fini);
498 MODULE_LICENSE("GPL");
499 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
500 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
501
502 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);