[IPSEC]: Get nexthdr from caller in xfrm6_rcv_spi
[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/module.h>
25 #include <linux/xfrm.h>
26 #include <linux/list.h>
27 #include <net/ip.h>
28 #include <net/xfrm.h>
29 #include <net/ipv6.h>
30 #include <linux/ipv6.h>
31 #include <linux/icmpv6.h>
32 #include <linux/mutex.h>
33
34 /*
35  * xfrm_tunnel_spi things are for allocating unique id ("spi")
36  * per xfrm_address_t.
37  */
38 struct xfrm6_tunnel_spi {
39         struct hlist_node list_byaddr;
40         struct hlist_node list_byspi;
41         xfrm_address_t addr;
42         u32 spi;
43         atomic_t refcnt;
44 };
45
46 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
47
48 static u32 xfrm6_tunnel_spi;
49
50 #define XFRM6_TUNNEL_SPI_MIN    1
51 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
52
53 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
54
55 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
56 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
57
58 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
59 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
60
61 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
62 {
63         unsigned h;
64
65         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
66         h ^= h >> 16;
67         h ^= h >> 8;
68         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
69
70         return h;
71 }
72
73 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
74 {
75         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
76 }
77
78
79 static int xfrm6_tunnel_spi_init(void)
80 {
81         int i;
82
83         xfrm6_tunnel_spi = 0;
84         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
85                                                   sizeof(struct xfrm6_tunnel_spi),
86                                                   0, SLAB_HWCACHE_ALIGN,
87                                                   NULL);
88         if (!xfrm6_tunnel_spi_kmem)
89                 return -ENOMEM;
90
91         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
92                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
93         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
94                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
95         return 0;
96 }
97
98 static void xfrm6_tunnel_spi_fini(void)
99 {
100         int i;
101
102         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
103                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
104                         return;
105         }
106         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
107                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
108                         return;
109         }
110         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
111         xfrm6_tunnel_spi_kmem = NULL;
112 }
113
114 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
115 {
116         struct xfrm6_tunnel_spi *x6spi;
117         struct hlist_node *pos;
118
119         hlist_for_each_entry(x6spi, pos,
120                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
121                              list_byaddr) {
122                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
123                         return x6spi;
124         }
125
126         return NULL;
127 }
128
129 __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
130 {
131         struct xfrm6_tunnel_spi *x6spi;
132         u32 spi;
133
134         read_lock_bh(&xfrm6_tunnel_spi_lock);
135         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
136         spi = x6spi ? x6spi->spi : 0;
137         read_unlock_bh(&xfrm6_tunnel_spi_lock);
138         return htonl(spi);
139 }
140
141 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
142
143 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
144 {
145         u32 spi;
146         struct xfrm6_tunnel_spi *x6spi;
147         struct hlist_node *pos;
148         unsigned index;
149
150         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
151             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
152                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
153         else
154                 xfrm6_tunnel_spi++;
155
156         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
157                 index = xfrm6_tunnel_spi_hash_byspi(spi);
158                 hlist_for_each_entry(x6spi, pos,
159                                      &xfrm6_tunnel_spi_byspi[index],
160                                      list_byspi) {
161                         if (x6spi->spi == spi)
162                                 goto try_next_1;
163                 }
164                 xfrm6_tunnel_spi = spi;
165                 goto alloc_spi;
166 try_next_1:;
167         }
168         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
169                 index = xfrm6_tunnel_spi_hash_byspi(spi);
170                 hlist_for_each_entry(x6spi, pos,
171                                      &xfrm6_tunnel_spi_byspi[index],
172                                      list_byspi) {
173                         if (x6spi->spi == spi)
174                                 goto try_next_2;
175                 }
176                 xfrm6_tunnel_spi = spi;
177                 goto alloc_spi;
178 try_next_2:;
179         }
180         spi = 0;
181         goto out;
182 alloc_spi:
183         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
184         if (!x6spi)
185                 goto out;
186
187         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
188         x6spi->spi = spi;
189         atomic_set(&x6spi->refcnt, 1);
190
191         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
192
193         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
194         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
195 out:
196         return spi;
197 }
198
199 __be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
200 {
201         struct xfrm6_tunnel_spi *x6spi;
202         u32 spi;
203
204         write_lock_bh(&xfrm6_tunnel_spi_lock);
205         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
206         if (x6spi) {
207                 atomic_inc(&x6spi->refcnt);
208                 spi = x6spi->spi;
209         } else
210                 spi = __xfrm6_tunnel_alloc_spi(saddr);
211         write_unlock_bh(&xfrm6_tunnel_spi_lock);
212
213         return htonl(spi);
214 }
215
216 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
217
218 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
219 {
220         struct xfrm6_tunnel_spi *x6spi;
221         struct hlist_node *pos, *n;
222
223         write_lock_bh(&xfrm6_tunnel_spi_lock);
224
225         hlist_for_each_entry_safe(x6spi, pos, n,
226                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
227                                   list_byaddr)
228         {
229                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
230                         if (atomic_dec_and_test(&x6spi->refcnt)) {
231                                 hlist_del(&x6spi->list_byaddr);
232                                 hlist_del(&x6spi->list_byspi);
233                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
234                                 break;
235                         }
236                 }
237         }
238         write_unlock_bh(&xfrm6_tunnel_spi_lock);
239 }
240
241 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
242
243 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
244 {
245         skb_push(skb, -skb_network_offset(skb));
246         return 0;
247 }
248
249 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
250 {
251         return skb_network_header(skb)[IP6CB(skb)->nhoff];
252 }
253
254 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
255 {
256         struct ipv6hdr *iph = ipv6_hdr(skb);
257         __be32 spi;
258
259         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
260         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
261 }
262
263 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
264                             int type, int code, int offset, __be32 info)
265 {
266         /* xfrm6_tunnel native err handling */
267         switch (type) {
268         case ICMPV6_DEST_UNREACH:
269                 switch (code) {
270                 case ICMPV6_NOROUTE:
271                 case ICMPV6_ADM_PROHIBITED:
272                 case ICMPV6_NOT_NEIGHBOUR:
273                 case ICMPV6_ADDR_UNREACH:
274                 case ICMPV6_PORT_UNREACH:
275                 default:
276                         break;
277                 }
278                 break;
279         case ICMPV6_PKT_TOOBIG:
280                 break;
281         case ICMPV6_TIME_EXCEED:
282                 switch (code) {
283                 case ICMPV6_EXC_HOPLIMIT:
284                         break;
285                 case ICMPV6_EXC_FRAGTIME:
286                 default:
287                         break;
288                 }
289                 break;
290         case ICMPV6_PARAMPROB:
291                 switch (code) {
292                 case ICMPV6_HDR_FIELD: break;
293                 case ICMPV6_UNK_NEXTHDR: break;
294                 case ICMPV6_UNK_OPTION: break;
295                 }
296                 break;
297         default:
298                 break;
299         }
300
301         return 0;
302 }
303
304 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
305 {
306         if (x->props.mode != XFRM_MODE_TUNNEL)
307                 return -EINVAL;
308
309         if (x->encap)
310                 return -EINVAL;
311
312         x->props.header_len = sizeof(struct ipv6hdr);
313
314         return 0;
315 }
316
317 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
318 {
319         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
320 }
321
322 static struct xfrm_type xfrm6_tunnel_type = {
323         .description    = "IP6IP6",
324         .owner          = THIS_MODULE,
325         .proto          = IPPROTO_IPV6,
326         .init_state     = xfrm6_tunnel_init_state,
327         .destructor     = xfrm6_tunnel_destroy,
328         .input          = xfrm6_tunnel_input,
329         .output         = xfrm6_tunnel_output,
330 };
331
332 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
333         .handler        = xfrm6_tunnel_rcv,
334         .err_handler    = xfrm6_tunnel_err,
335         .priority       = 2,
336 };
337
338 static struct xfrm6_tunnel xfrm46_tunnel_handler = {
339         .handler        = xfrm6_tunnel_rcv,
340         .err_handler    = xfrm6_tunnel_err,
341         .priority       = 2,
342 };
343
344 static int __init xfrm6_tunnel_init(void)
345 {
346         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0)
347                 return -EAGAIN;
348
349         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6)) {
350                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
351                 return -EAGAIN;
352         }
353         if (xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET)) {
354                 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
355                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
356                 return -EAGAIN;
357         }
358         if (xfrm6_tunnel_spi_init() < 0) {
359                 xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
360                 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
361                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
362                 return -EAGAIN;
363         }
364         return 0;
365 }
366
367 static void __exit xfrm6_tunnel_fini(void)
368 {
369         xfrm6_tunnel_spi_fini();
370         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
371         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
372         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
373 }
374
375 module_init(xfrm6_tunnel_init);
376 module_exit(xfrm6_tunnel_fini);
377 MODULE_LICENSE("GPL");
378 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);