08f9abbdf1d75c40deb73561541b065384fda13b
[linux-2.6.git] / net / ipv6 / xfrm6_tunnel.c
1 /*
2  * Copyright (C)2003,2004 USAGI/WIDE Project
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  * 
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  * 
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17  *
18  * Authors      Mitsuru KANDA  <mk@linux-ipv6.org>
19  *              YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
20  *
21  * Based on net/ipv4/xfrm4_tunnel.c
22  *
23  */
24 #include <linux/config.h>
25 #include <linux/module.h>
26 #include <linux/xfrm.h>
27 #include <linux/list.h>
28 #include <net/ip.h>
29 #include <net/xfrm.h>
30 #include <net/ipv6.h>
31 #include <net/protocol.h>
32 #include <linux/ipv6.h>
33 #include <linux/icmpv6.h>
34 #include <linux/mutex.h>
35
36 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
37 # define X6TDEBUG       3
38 #else
39 # define X6TDEBUG       1
40 #endif
41
42 #define X6TPRINTK(fmt, args...)         printk(fmt, ## args)
43 #define X6TNOPRINTK(fmt, args...)       do { ; } while(0)
44
45 #if X6TDEBUG >= 1
46 # define X6TPRINTK1     X6TPRINTK
47 #else
48 # define X6TPRINTK1     X6TNOPRINTK
49 #endif
50
51 #if X6TDEBUG >= 3
52 # define X6TPRINTK3     X6TPRINTK
53 #else
54 # define X6TPRINTK3     X6TNOPRINTK
55 #endif
56
57 /*
58  * xfrm_tunnel_spi things are for allocating unique id ("spi") 
59  * per xfrm_address_t.
60  */
61 struct xfrm6_tunnel_spi {
62         struct hlist_node list_byaddr;
63         struct hlist_node list_byspi;
64         xfrm_address_t addr;
65         u32 spi;
66         atomic_t refcnt;
67 #ifdef XFRM6_TUNNEL_SPI_MAGIC
68         u32 magic;
69 #endif
70 };
71
72 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
73 # define XFRM6_TUNNEL_SPI_MAGIC 0xdeadbeef
74 #endif
75
76 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
77
78 static u32 xfrm6_tunnel_spi;
79
80 #define XFRM6_TUNNEL_SPI_MIN    1
81 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
82
83 static kmem_cache_t *xfrm6_tunnel_spi_kmem __read_mostly;
84
85 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
86 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
87
88 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
89 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
90
91 #ifdef XFRM6_TUNNEL_SPI_MAGIC
92 static int x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
93                              const char *name)
94 {
95         if (unlikely(x6spi->magic != XFRM6_TUNNEL_SPI_MAGIC)) {
96                 X6TPRINTK3(KERN_DEBUG "%s(): x6spi object "
97                                       "at %p has corrupted magic %08x "
98                                       "(should be %08x)\n",
99                            name, x6spi, x6spi->magic, XFRM6_TUNNEL_SPI_MAGIC);
100                 return -1;
101         }
102         return 0;
103 }
104 #else
105 static int inline x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
106                                     const char *name)
107 {
108         return 0;
109 }
110 #endif
111
112 #define X6SPI_CHECK_MAGIC(x6spi) x6spi_check_magic((x6spi), __FUNCTION__)
113
114
115 static unsigned inline xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
116 {
117         unsigned h;
118
119         X6TPRINTK3(KERN_DEBUG "%s(addr=%p)\n", __FUNCTION__, addr);
120
121         h = addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3];
122         h ^= h >> 16;
123         h ^= h >> 8;
124         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
125
126         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, h);
127
128         return h;
129 }
130
131 static unsigned inline xfrm6_tunnel_spi_hash_byspi(u32 spi)
132 {
133         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
134 }
135
136
137 static int xfrm6_tunnel_spi_init(void)
138 {
139         int i;
140
141         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
142
143         xfrm6_tunnel_spi = 0;
144         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
145                                                   sizeof(struct xfrm6_tunnel_spi),
146                                                   0, SLAB_HWCACHE_ALIGN,
147                                                   NULL, NULL);
148         if (!xfrm6_tunnel_spi_kmem) {
149                 X6TPRINTK1(KERN_ERR
150                            "%s(): failed to allocate xfrm6_tunnel_spi_kmem\n",
151                            __FUNCTION__);
152                 return -ENOMEM;
153         }
154
155         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
156                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
157         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
158                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
159         return 0;
160 }
161
162 static void xfrm6_tunnel_spi_fini(void)
163 {
164         int i;
165
166         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
167
168         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
169                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
170                         goto err;
171         }
172         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
173                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
174                         goto err;
175         }
176         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
177         xfrm6_tunnel_spi_kmem = NULL;
178         return;
179 err:
180         X6TPRINTK1(KERN_ERR "%s(): table is not empty\n", __FUNCTION__);
181         return;
182 }
183
184 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
185 {
186         struct xfrm6_tunnel_spi *x6spi;
187         struct hlist_node *pos;
188
189         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
190
191         hlist_for_each_entry(x6spi, pos,
192                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
193                              list_byaddr) {
194                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
195                         X6SPI_CHECK_MAGIC(x6spi);
196                         X6TPRINTK3(KERN_DEBUG "%s() = %p(%u)\n", __FUNCTION__, x6spi, x6spi->spi);
197                         return x6spi;
198                 }
199         }
200
201         X6TPRINTK3(KERN_DEBUG "%s() = NULL(0)\n", __FUNCTION__);
202         return NULL;
203 }
204
205 u32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
206 {
207         struct xfrm6_tunnel_spi *x6spi;
208         u32 spi;
209
210         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
211
212         read_lock_bh(&xfrm6_tunnel_spi_lock);
213         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
214         spi = x6spi ? x6spi->spi : 0;
215         read_unlock_bh(&xfrm6_tunnel_spi_lock);
216         return spi;
217 }
218
219 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
220
221 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
222 {
223         u32 spi;
224         struct xfrm6_tunnel_spi *x6spi;
225         struct hlist_node *pos;
226         unsigned index;
227
228         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
229
230         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
231             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
232                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
233         else
234                 xfrm6_tunnel_spi++;
235
236         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
237                 index = xfrm6_tunnel_spi_hash_byspi(spi);
238                 hlist_for_each_entry(x6spi, pos, 
239                                      &xfrm6_tunnel_spi_byspi[index], 
240                                      list_byspi) {
241                         if (x6spi->spi == spi)
242                                 goto try_next_1;
243                 }
244                 xfrm6_tunnel_spi = spi;
245                 goto alloc_spi;
246 try_next_1:;
247         }
248         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
249                 index = xfrm6_tunnel_spi_hash_byspi(spi);
250                 hlist_for_each_entry(x6spi, pos, 
251                                      &xfrm6_tunnel_spi_byspi[index], 
252                                      list_byspi) {
253                         if (x6spi->spi == spi)
254                                 goto try_next_2;
255                 }
256                 xfrm6_tunnel_spi = spi;
257                 goto alloc_spi;
258 try_next_2:;
259         }
260         spi = 0;
261         goto out;
262 alloc_spi:
263         X6TPRINTK3(KERN_DEBUG "%s(): allocate new spi for " NIP6_FMT "\n",
264                               __FUNCTION__, 
265                               NIP6(*(struct in6_addr *)saddr));
266         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, SLAB_ATOMIC);
267         if (!x6spi) {
268                 X6TPRINTK1(KERN_ERR "%s(): kmem_cache_alloc() failed\n", 
269                            __FUNCTION__);
270                 goto out;
271         }
272 #ifdef XFRM6_TUNNEL_SPI_MAGIC
273         x6spi->magic = XFRM6_TUNNEL_SPI_MAGIC;
274 #endif
275         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
276         x6spi->spi = spi;
277         atomic_set(&x6spi->refcnt, 1);
278
279         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
280
281         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
282         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
283         X6SPI_CHECK_MAGIC(x6spi);
284 out:
285         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
286         return spi;
287 }
288
289 u32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
290 {
291         struct xfrm6_tunnel_spi *x6spi;
292         u32 spi;
293
294         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
295
296         write_lock_bh(&xfrm6_tunnel_spi_lock);
297         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
298         if (x6spi) {
299                 atomic_inc(&x6spi->refcnt);
300                 spi = x6spi->spi;
301         } else
302                 spi = __xfrm6_tunnel_alloc_spi(saddr);
303         write_unlock_bh(&xfrm6_tunnel_spi_lock);
304
305         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
306
307         return spi;
308 }
309
310 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
311
312 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
313 {
314         struct xfrm6_tunnel_spi *x6spi;
315         struct hlist_node *pos, *n;
316
317         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
318
319         write_lock_bh(&xfrm6_tunnel_spi_lock);
320
321         hlist_for_each_entry_safe(x6spi, pos, n, 
322                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
323                                   list_byaddr)
324         {
325                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
326                         X6TPRINTK3(KERN_DEBUG "%s(): x6spi object for " NIP6_FMT 
327                                               " found at %p\n",
328                                    __FUNCTION__, 
329                                    NIP6(*(struct in6_addr *)saddr),
330                                    x6spi);
331                         X6SPI_CHECK_MAGIC(x6spi);
332                         if (atomic_dec_and_test(&x6spi->refcnt)) {
333                                 hlist_del(&x6spi->list_byaddr);
334                                 hlist_del(&x6spi->list_byspi);
335                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
336                                 break;
337                         }
338                 }
339         }
340         write_unlock_bh(&xfrm6_tunnel_spi_lock);
341 }
342
343 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
344
345 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
346 {
347         struct ipv6hdr *top_iph;
348
349         top_iph = (struct ipv6hdr *)skb->data;
350         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
351
352         return 0;
353 }
354
355 static int xfrm6_tunnel_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
356 {
357         return 0;
358 }
359
360 static struct xfrm6_tunnel *xfrm6_tunnel_handler;
361 static DEFINE_MUTEX(xfrm6_tunnel_mutex);
362
363 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler)
364 {
365         int ret;
366
367         mutex_lock(&xfrm6_tunnel_mutex);
368         ret = 0;
369         if (xfrm6_tunnel_handler != NULL)
370                 ret = -EINVAL;
371         if (!ret)
372                 xfrm6_tunnel_handler = handler;
373         mutex_unlock(&xfrm6_tunnel_mutex);
374
375         return ret;
376 }
377
378 EXPORT_SYMBOL(xfrm6_tunnel_register);
379
380 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler)
381 {
382         int ret;
383
384         mutex_lock(&xfrm6_tunnel_mutex);
385         ret = 0;
386         if (xfrm6_tunnel_handler != handler)
387                 ret = -EINVAL;
388         if (!ret)
389                 xfrm6_tunnel_handler = NULL;
390         mutex_unlock(&xfrm6_tunnel_mutex);
391
392         synchronize_net();
393
394         return ret;
395 }
396
397 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
398
399 static int xfrm6_tunnel_rcv(struct sk_buff **pskb)
400 {
401         struct sk_buff *skb = *pskb;
402         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
403         struct ipv6hdr *iph = skb->nh.ipv6h;
404         u32 spi;
405
406         /* device-like_ip6ip6_handler() */
407         if (handler && handler->handler(pskb) == 0)
408                 return 0;
409
410         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
411         return xfrm6_rcv_spi(pskb, spi);
412 }
413
414 static void xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
415                              int type, int code, int offset, __u32 info)
416 {
417         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
418
419         /* call here first for device-like ip6ip6 err handling */
420         if (handler) {
421                 handler->err_handler(skb, opt, type, code, offset, info);
422                 return;
423         }
424
425         /* xfrm6_tunnel native err handling */
426         switch (type) {
427         case ICMPV6_DEST_UNREACH: 
428                 switch (code) {
429                 case ICMPV6_NOROUTE: 
430                 case ICMPV6_ADM_PROHIBITED:
431                 case ICMPV6_NOT_NEIGHBOUR:
432                 case ICMPV6_ADDR_UNREACH:
433                 case ICMPV6_PORT_UNREACH:
434                 default:
435                         X6TPRINTK3(KERN_DEBUG
436                                    "xfrm6_tunnel: Destination Unreach.\n");
437                         break;
438                 }
439                 break;
440         case ICMPV6_PKT_TOOBIG:
441                         X6TPRINTK3(KERN_DEBUG 
442                                    "xfrm6_tunnel: Packet Too Big.\n");
443                 break;
444         case ICMPV6_TIME_EXCEED:
445                 switch (code) {
446                 case ICMPV6_EXC_HOPLIMIT:
447                         X6TPRINTK3(KERN_DEBUG
448                                    "xfrm6_tunnel: Too small Hoplimit.\n");
449                         break;
450                 case ICMPV6_EXC_FRAGTIME:
451                 default: 
452                         break;
453                 }
454                 break;
455         case ICMPV6_PARAMPROB:
456                 switch (code) {
457                 case ICMPV6_HDR_FIELD: break;
458                 case ICMPV6_UNK_NEXTHDR: break;
459                 case ICMPV6_UNK_OPTION: break;
460                 }
461                 break;
462         default:
463                 break;
464         }
465         return;
466 }
467
468 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
469 {
470         if (!x->props.mode)
471                 return -EINVAL;
472
473         if (x->encap)
474                 return -EINVAL;
475
476         x->props.header_len = sizeof(struct ipv6hdr);
477
478         return 0;
479 }
480
481 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
482 {
483         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
484 }
485
486 static struct xfrm_type xfrm6_tunnel_type = {
487         .description    = "IP6IP6",
488         .owner          = THIS_MODULE,
489         .proto          = IPPROTO_IPV6,
490         .init_state     = xfrm6_tunnel_init_state,
491         .destructor     = xfrm6_tunnel_destroy,
492         .input          = xfrm6_tunnel_input,
493         .output         = xfrm6_tunnel_output,
494 };
495
496 static struct inet6_protocol xfrm6_tunnel_protocol = {
497         .handler        = xfrm6_tunnel_rcv,
498         .err_handler    = xfrm6_tunnel_err, 
499         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
500 };
501
502 static int __init xfrm6_tunnel_init(void)
503 {
504         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
505
506         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
507                 X6TPRINTK1(KERN_ERR
508                            "xfrm6_tunnel init: can't add xfrm type\n");
509                 return -EAGAIN;
510         }
511         if (inet6_add_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0) {
512                 X6TPRINTK1(KERN_ERR
513                            "xfrm6_tunnel init(): can't add protocol\n");
514                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
515                 return -EAGAIN;
516         }
517         if (xfrm6_tunnel_spi_init() < 0) {
518                 X6TPRINTK1(KERN_ERR
519                            "xfrm6_tunnel init: failed to initialize spi\n");
520                 inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6);
521                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
522                 return -EAGAIN;
523         }
524         return 0;
525 }
526
527 static void __exit xfrm6_tunnel_fini(void)
528 {
529         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
530
531         xfrm6_tunnel_spi_fini();
532         if (inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0)
533                 X6TPRINTK1(KERN_ERR 
534                            "xfrm6_tunnel close: can't remove protocol\n");
535         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
536                 X6TPRINTK1(KERN_ERR
537                            "xfrm6_tunnel close: can't remove xfrm type\n");
538 }
539
540 module_init(xfrm6_tunnel_init);
541 module_exit(xfrm6_tunnel_fini);
542 MODULE_LICENSE("GPL");