[NET]: Use NIP6_FMT in kernel.h
[linux-2.6.git] / 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/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 <net/protocol.h>
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:
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/" NIP6_FMT "\n",
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
236         if (xfrm_init_state(t))
237                 goto error;
238
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);
289                 if (scratch)
290                         vfree(scratch);
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);
343                 crypto_free_tfm(tfm);
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. */
355         cpu = raw_smp_processor_id();
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
416 static int ipcomp6_init_state(struct xfrm_state *x)
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