[INET]: Introduce tunnel4/tunnel6
[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 <linux/ipv6.h>
32 #include <linux/icmpv6.h>
33 #include <linux/mutex.h>
34
35 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
36 # define X6TDEBUG       3
37 #else
38 # define X6TDEBUG       1
39 #endif
40
41 #define X6TPRINTK(fmt, args...)         printk(fmt, ## args)
42 #define X6TNOPRINTK(fmt, args...)       do { ; } while(0)
43
44 #if X6TDEBUG >= 1
45 # define X6TPRINTK1     X6TPRINTK
46 #else
47 # define X6TPRINTK1     X6TNOPRINTK
48 #endif
49
50 #if X6TDEBUG >= 3
51 # define X6TPRINTK3     X6TPRINTK
52 #else
53 # define X6TPRINTK3     X6TNOPRINTK
54 #endif
55
56 /*
57  * xfrm_tunnel_spi things are for allocating unique id ("spi") 
58  * per xfrm_address_t.
59  */
60 struct xfrm6_tunnel_spi {
61         struct hlist_node list_byaddr;
62         struct hlist_node list_byspi;
63         xfrm_address_t addr;
64         u32 spi;
65         atomic_t refcnt;
66 #ifdef XFRM6_TUNNEL_SPI_MAGIC
67         u32 magic;
68 #endif
69 };
70
71 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
72 # define XFRM6_TUNNEL_SPI_MAGIC 0xdeadbeef
73 #endif
74
75 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
76
77 static u32 xfrm6_tunnel_spi;
78
79 #define XFRM6_TUNNEL_SPI_MIN    1
80 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
81
82 static kmem_cache_t *xfrm6_tunnel_spi_kmem __read_mostly;
83
84 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
85 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
86
87 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
88 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
89
90 #ifdef XFRM6_TUNNEL_SPI_MAGIC
91 static int x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
92                              const char *name)
93 {
94         if (unlikely(x6spi->magic != XFRM6_TUNNEL_SPI_MAGIC)) {
95                 X6TPRINTK3(KERN_DEBUG "%s(): x6spi object "
96                                       "at %p has corrupted magic %08x "
97                                       "(should be %08x)\n",
98                            name, x6spi, x6spi->magic, XFRM6_TUNNEL_SPI_MAGIC);
99                 return -1;
100         }
101         return 0;
102 }
103 #else
104 static int inline x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
105                                     const char *name)
106 {
107         return 0;
108 }
109 #endif
110
111 #define X6SPI_CHECK_MAGIC(x6spi) x6spi_check_magic((x6spi), __FUNCTION__)
112
113
114 static unsigned inline xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
115 {
116         unsigned h;
117
118         X6TPRINTK3(KERN_DEBUG "%s(addr=%p)\n", __FUNCTION__, addr);
119
120         h = addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3];
121         h ^= h >> 16;
122         h ^= h >> 8;
123         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
124
125         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, h);
126
127         return h;
128 }
129
130 static unsigned inline xfrm6_tunnel_spi_hash_byspi(u32 spi)
131 {
132         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
133 }
134
135
136 static int xfrm6_tunnel_spi_init(void)
137 {
138         int i;
139
140         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
141
142         xfrm6_tunnel_spi = 0;
143         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
144                                                   sizeof(struct xfrm6_tunnel_spi),
145                                                   0, SLAB_HWCACHE_ALIGN,
146                                                   NULL, NULL);
147         if (!xfrm6_tunnel_spi_kmem) {
148                 X6TPRINTK1(KERN_ERR
149                            "%s(): failed to allocate xfrm6_tunnel_spi_kmem\n",
150                            __FUNCTION__);
151                 return -ENOMEM;
152         }
153
154         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
155                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
156         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
157                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
158         return 0;
159 }
160
161 static void xfrm6_tunnel_spi_fini(void)
162 {
163         int i;
164
165         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
166
167         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
168                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
169                         goto err;
170         }
171         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
172                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
173                         goto err;
174         }
175         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
176         xfrm6_tunnel_spi_kmem = NULL;
177         return;
178 err:
179         X6TPRINTK1(KERN_ERR "%s(): table is not empty\n", __FUNCTION__);
180         return;
181 }
182
183 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
184 {
185         struct xfrm6_tunnel_spi *x6spi;
186         struct hlist_node *pos;
187
188         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
189
190         hlist_for_each_entry(x6spi, pos,
191                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
192                              list_byaddr) {
193                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
194                         X6SPI_CHECK_MAGIC(x6spi);
195                         X6TPRINTK3(KERN_DEBUG "%s() = %p(%u)\n", __FUNCTION__, x6spi, x6spi->spi);
196                         return x6spi;
197                 }
198         }
199
200         X6TPRINTK3(KERN_DEBUG "%s() = NULL(0)\n", __FUNCTION__);
201         return NULL;
202 }
203
204 u32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
205 {
206         struct xfrm6_tunnel_spi *x6spi;
207         u32 spi;
208
209         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
210
211         read_lock_bh(&xfrm6_tunnel_spi_lock);
212         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
213         spi = x6spi ? x6spi->spi : 0;
214         read_unlock_bh(&xfrm6_tunnel_spi_lock);
215         return spi;
216 }
217
218 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
219
220 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
221 {
222         u32 spi;
223         struct xfrm6_tunnel_spi *x6spi;
224         struct hlist_node *pos;
225         unsigned index;
226
227         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
228
229         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
230             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
231                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
232         else
233                 xfrm6_tunnel_spi++;
234
235         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
236                 index = xfrm6_tunnel_spi_hash_byspi(spi);
237                 hlist_for_each_entry(x6spi, pos, 
238                                      &xfrm6_tunnel_spi_byspi[index], 
239                                      list_byspi) {
240                         if (x6spi->spi == spi)
241                                 goto try_next_1;
242                 }
243                 xfrm6_tunnel_spi = spi;
244                 goto alloc_spi;
245 try_next_1:;
246         }
247         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
248                 index = xfrm6_tunnel_spi_hash_byspi(spi);
249                 hlist_for_each_entry(x6spi, pos, 
250                                      &xfrm6_tunnel_spi_byspi[index], 
251                                      list_byspi) {
252                         if (x6spi->spi == spi)
253                                 goto try_next_2;
254                 }
255                 xfrm6_tunnel_spi = spi;
256                 goto alloc_spi;
257 try_next_2:;
258         }
259         spi = 0;
260         goto out;
261 alloc_spi:
262         X6TPRINTK3(KERN_DEBUG "%s(): allocate new spi for " NIP6_FMT "\n",
263                               __FUNCTION__, 
264                               NIP6(*(struct in6_addr *)saddr));
265         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, SLAB_ATOMIC);
266         if (!x6spi) {
267                 X6TPRINTK1(KERN_ERR "%s(): kmem_cache_alloc() failed\n", 
268                            __FUNCTION__);
269                 goto out;
270         }
271 #ifdef XFRM6_TUNNEL_SPI_MAGIC
272         x6spi->magic = XFRM6_TUNNEL_SPI_MAGIC;
273 #endif
274         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
275         x6spi->spi = spi;
276         atomic_set(&x6spi->refcnt, 1);
277
278         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
279
280         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
281         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
282         X6SPI_CHECK_MAGIC(x6spi);
283 out:
284         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
285         return spi;
286 }
287
288 u32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
289 {
290         struct xfrm6_tunnel_spi *x6spi;
291         u32 spi;
292
293         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
294
295         write_lock_bh(&xfrm6_tunnel_spi_lock);
296         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
297         if (x6spi) {
298                 atomic_inc(&x6spi->refcnt);
299                 spi = x6spi->spi;
300         } else
301                 spi = __xfrm6_tunnel_alloc_spi(saddr);
302         write_unlock_bh(&xfrm6_tunnel_spi_lock);
303
304         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
305
306         return spi;
307 }
308
309 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
310
311 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
312 {
313         struct xfrm6_tunnel_spi *x6spi;
314         struct hlist_node *pos, *n;
315
316         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
317
318         write_lock_bh(&xfrm6_tunnel_spi_lock);
319
320         hlist_for_each_entry_safe(x6spi, pos, n, 
321                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
322                                   list_byaddr)
323         {
324                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
325                         X6TPRINTK3(KERN_DEBUG "%s(): x6spi object for " NIP6_FMT 
326                                               " found at %p\n",
327                                    __FUNCTION__, 
328                                    NIP6(*(struct in6_addr *)saddr),
329                                    x6spi);
330                         X6SPI_CHECK_MAGIC(x6spi);
331                         if (atomic_dec_and_test(&x6spi->refcnt)) {
332                                 hlist_del(&x6spi->list_byaddr);
333                                 hlist_del(&x6spi->list_byspi);
334                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
335                                 break;
336                         }
337                 }
338         }
339         write_unlock_bh(&xfrm6_tunnel_spi_lock);
340 }
341
342 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
343
344 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
345 {
346         struct ipv6hdr *top_iph;
347
348         top_iph = (struct ipv6hdr *)skb->data;
349         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
350
351         return 0;
352 }
353
354 static int xfrm6_tunnel_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
355 {
356         return 0;
357 }
358
359 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
360 {
361         struct ipv6hdr *iph = skb->nh.ipv6h;
362         u32 spi;
363
364         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
365         return xfrm6_rcv_spi(skb, spi);
366 }
367
368 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
369                             int type, int code, int offset, __u32 info)
370 {
371         /* xfrm6_tunnel native err handling */
372         switch (type) {
373         case ICMPV6_DEST_UNREACH: 
374                 switch (code) {
375                 case ICMPV6_NOROUTE: 
376                 case ICMPV6_ADM_PROHIBITED:
377                 case ICMPV6_NOT_NEIGHBOUR:
378                 case ICMPV6_ADDR_UNREACH:
379                 case ICMPV6_PORT_UNREACH:
380                 default:
381                         X6TPRINTK3(KERN_DEBUG
382                                    "xfrm6_tunnel: Destination Unreach.\n");
383                         break;
384                 }
385                 break;
386         case ICMPV6_PKT_TOOBIG:
387                         X6TPRINTK3(KERN_DEBUG 
388                                    "xfrm6_tunnel: Packet Too Big.\n");
389                 break;
390         case ICMPV6_TIME_EXCEED:
391                 switch (code) {
392                 case ICMPV6_EXC_HOPLIMIT:
393                         X6TPRINTK3(KERN_DEBUG
394                                    "xfrm6_tunnel: Too small Hoplimit.\n");
395                         break;
396                 case ICMPV6_EXC_FRAGTIME:
397                 default: 
398                         break;
399                 }
400                 break;
401         case ICMPV6_PARAMPROB:
402                 switch (code) {
403                 case ICMPV6_HDR_FIELD: break;
404                 case ICMPV6_UNK_NEXTHDR: break;
405                 case ICMPV6_UNK_OPTION: break;
406                 }
407                 break;
408         default:
409                 break;
410         }
411
412         return 0;
413 }
414
415 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
416 {
417         if (!x->props.mode)
418                 return -EINVAL;
419
420         if (x->encap)
421                 return -EINVAL;
422
423         x->props.header_len = sizeof(struct ipv6hdr);
424
425         return 0;
426 }
427
428 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
429 {
430         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
431 }
432
433 static struct xfrm_type xfrm6_tunnel_type = {
434         .description    = "IP6IP6",
435         .owner          = THIS_MODULE,
436         .proto          = IPPROTO_IPV6,
437         .init_state     = xfrm6_tunnel_init_state,
438         .destructor     = xfrm6_tunnel_destroy,
439         .input          = xfrm6_tunnel_input,
440         .output         = xfrm6_tunnel_output,
441 };
442
443 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
444         .handler        = xfrm6_tunnel_rcv,
445         .err_handler    = xfrm6_tunnel_err,
446         .priority       = 2,
447 };
448
449 static int __init xfrm6_tunnel_init(void)
450 {
451         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
452
453         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
454                 X6TPRINTK1(KERN_ERR
455                            "xfrm6_tunnel init: can't add xfrm type\n");
456                 return -EAGAIN;
457         }
458         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler)) {
459                 X6TPRINTK1(KERN_ERR
460                            "xfrm6_tunnel init(): can't add handler\n");
461                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
462                 return -EAGAIN;
463         }
464         if (xfrm6_tunnel_spi_init() < 0) {
465                 X6TPRINTK1(KERN_ERR
466                            "xfrm6_tunnel init: failed to initialize spi\n");
467                 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler);
468                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
469                 return -EAGAIN;
470         }
471         return 0;
472 }
473
474 static void __exit xfrm6_tunnel_fini(void)
475 {
476         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
477
478         xfrm6_tunnel_spi_fini();
479         if (xfrm6_tunnel_deregister(&xfrm6_tunnel_handler))
480                 X6TPRINTK1(KERN_ERR 
481                            "xfrm6_tunnel close: can't remove handler\n");
482         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
483                 X6TPRINTK1(KERN_ERR
484                            "xfrm6_tunnel close: can't remove xfrm type\n");
485 }
486
487 module_init(xfrm6_tunnel_init);
488 module_exit(xfrm6_tunnel_fini);
489 MODULE_LICENSE("GPL");