netfilter: add nf_ipv6_ops hook to fix xt_addrtype with IPv6
[linux-3.10.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/slab.h>
27 #include <linux/rculist.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 #include <net/netns/generic.h>
35
36 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
37 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
38
39 #define XFRM6_TUNNEL_SPI_MIN    1
40 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
41
42 struct xfrm6_tunnel_net {
43         struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
44         struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
45         u32 spi;
46 };
47
48 static int xfrm6_tunnel_net_id __read_mostly;
49 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
50 {
51         return net_generic(net, xfrm6_tunnel_net_id);
52 }
53
54 /*
55  * xfrm_tunnel_spi things are for allocating unique id ("spi")
56  * per xfrm_address_t.
57  */
58 struct xfrm6_tunnel_spi {
59         struct hlist_node       list_byaddr;
60         struct hlist_node       list_byspi;
61         xfrm_address_t          addr;
62         u32                     spi;
63         atomic_t                refcnt;
64         struct rcu_head         rcu_head;
65 };
66
67 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
68
69 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
70
71 static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
72 {
73         unsigned int h;
74
75         h = ipv6_addr_hash((const struct in6_addr *)addr);
76         h ^= h >> 16;
77         h ^= h >> 8;
78         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
79
80         return h;
81 }
82
83 static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
84 {
85         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
86 }
87
88 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
89 {
90         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
91         struct xfrm6_tunnel_spi *x6spi;
92
93         hlist_for_each_entry_rcu(x6spi,
94                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
95                              list_byaddr) {
96                 if (xfrm6_addr_equal(&x6spi->addr, saddr))
97                         return x6spi;
98         }
99
100         return NULL;
101 }
102
103 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
104 {
105         struct xfrm6_tunnel_spi *x6spi;
106         u32 spi;
107
108         rcu_read_lock_bh();
109         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
110         spi = x6spi ? x6spi->spi : 0;
111         rcu_read_unlock_bh();
112         return htonl(spi);
113 }
114
115 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
116
117 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
118 {
119         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
120         struct xfrm6_tunnel_spi *x6spi;
121         int index = xfrm6_tunnel_spi_hash_byspi(spi);
122
123         hlist_for_each_entry(x6spi,
124                              &xfrm6_tn->spi_byspi[index],
125                              list_byspi) {
126                 if (x6spi->spi == spi)
127                         return -1;
128         }
129         return index;
130 }
131
132 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
133 {
134         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
135         u32 spi;
136         struct xfrm6_tunnel_spi *x6spi;
137         int index;
138
139         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
140             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
141                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
142         else
143                 xfrm6_tn->spi++;
144
145         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
146                 index = __xfrm6_tunnel_spi_check(net, spi);
147                 if (index >= 0)
148                         goto alloc_spi;
149         }
150         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
151                 index = __xfrm6_tunnel_spi_check(net, spi);
152                 if (index >= 0)
153                         goto alloc_spi;
154         }
155         spi = 0;
156         goto out;
157 alloc_spi:
158         xfrm6_tn->spi = spi;
159         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
160         if (!x6spi)
161                 goto out;
162
163         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
164         x6spi->spi = spi;
165         atomic_set(&x6spi->refcnt, 1);
166
167         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
168
169         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
170         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
171 out:
172         return spi;
173 }
174
175 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
176 {
177         struct xfrm6_tunnel_spi *x6spi;
178         u32 spi;
179
180         spin_lock_bh(&xfrm6_tunnel_spi_lock);
181         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
182         if (x6spi) {
183                 atomic_inc(&x6spi->refcnt);
184                 spi = x6spi->spi;
185         } else
186                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
187         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
188
189         return htonl(spi);
190 }
191
192 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
193
194 static void x6spi_destroy_rcu(struct rcu_head *head)
195 {
196         kmem_cache_free(xfrm6_tunnel_spi_kmem,
197                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
198 }
199
200 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
201 {
202         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
203         struct xfrm6_tunnel_spi *x6spi;
204         struct hlist_node *n;
205
206         spin_lock_bh(&xfrm6_tunnel_spi_lock);
207
208         hlist_for_each_entry_safe(x6spi, n,
209                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
210                                   list_byaddr)
211         {
212                 if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
213                         if (atomic_dec_and_test(&x6spi->refcnt)) {
214                                 hlist_del_rcu(&x6spi->list_byaddr);
215                                 hlist_del_rcu(&x6spi->list_byspi);
216                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
217                                 break;
218                         }
219                 }
220         }
221         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
222 }
223
224 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
225 {
226         skb_push(skb, -skb_network_offset(skb));
227         return 0;
228 }
229
230 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
231 {
232         return skb_network_header(skb)[IP6CB(skb)->nhoff];
233 }
234
235 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
236 {
237         struct net *net = dev_net(skb->dev);
238         const struct ipv6hdr *iph = ipv6_hdr(skb);
239         __be32 spi;
240
241         spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
242         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi);
243 }
244
245 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
246                             u8 type, u8 code, int offset, __be32 info)
247 {
248         /* xfrm6_tunnel native err handling */
249         switch (type) {
250         case ICMPV6_DEST_UNREACH:
251                 switch (code) {
252                 case ICMPV6_NOROUTE:
253                 case ICMPV6_ADM_PROHIBITED:
254                 case ICMPV6_NOT_NEIGHBOUR:
255                 case ICMPV6_ADDR_UNREACH:
256                 case ICMPV6_PORT_UNREACH:
257                 default:
258                         break;
259                 }
260                 break;
261         case ICMPV6_PKT_TOOBIG:
262                 break;
263         case ICMPV6_TIME_EXCEED:
264                 switch (code) {
265                 case ICMPV6_EXC_HOPLIMIT:
266                         break;
267                 case ICMPV6_EXC_FRAGTIME:
268                 default:
269                         break;
270                 }
271                 break;
272         case ICMPV6_PARAMPROB:
273                 switch (code) {
274                 case ICMPV6_HDR_FIELD: break;
275                 case ICMPV6_UNK_NEXTHDR: break;
276                 case ICMPV6_UNK_OPTION: break;
277                 }
278                 break;
279         default:
280                 break;
281         }
282
283         return 0;
284 }
285
286 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
287 {
288         if (x->props.mode != XFRM_MODE_TUNNEL)
289                 return -EINVAL;
290
291         if (x->encap)
292                 return -EINVAL;
293
294         x->props.header_len = sizeof(struct ipv6hdr);
295
296         return 0;
297 }
298
299 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
300 {
301         struct net *net = xs_net(x);
302
303         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
304 }
305
306 static const struct xfrm_type xfrm6_tunnel_type = {
307         .description    = "IP6IP6",
308         .owner          = THIS_MODULE,
309         .proto          = IPPROTO_IPV6,
310         .init_state     = xfrm6_tunnel_init_state,
311         .destructor     = xfrm6_tunnel_destroy,
312         .input          = xfrm6_tunnel_input,
313         .output         = xfrm6_tunnel_output,
314 };
315
316 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
317         .handler        = xfrm6_tunnel_rcv,
318         .err_handler    = xfrm6_tunnel_err,
319         .priority       = 2,
320 };
321
322 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
323         .handler        = xfrm6_tunnel_rcv,
324         .err_handler    = xfrm6_tunnel_err,
325         .priority       = 2,
326 };
327
328 static int __net_init xfrm6_tunnel_net_init(struct net *net)
329 {
330         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
331         unsigned int i;
332
333         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
334                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
335         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
336                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
337         xfrm6_tn->spi = 0;
338
339         return 0;
340 }
341
342 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
343 {
344 }
345
346 static struct pernet_operations xfrm6_tunnel_net_ops = {
347         .init   = xfrm6_tunnel_net_init,
348         .exit   = xfrm6_tunnel_net_exit,
349         .id     = &xfrm6_tunnel_net_id,
350         .size   = sizeof(struct xfrm6_tunnel_net),
351 };
352
353 static int __init xfrm6_tunnel_init(void)
354 {
355         int rv;
356
357         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
358                                                   sizeof(struct xfrm6_tunnel_spi),
359                                                   0, SLAB_HWCACHE_ALIGN,
360                                                   NULL);
361         if (!xfrm6_tunnel_spi_kmem)
362                 return -ENOMEM;
363         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
364         if (rv < 0)
365                 goto out_pernet;
366         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
367         if (rv < 0)
368                 goto out_type;
369         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
370         if (rv < 0)
371                 goto out_xfrm6;
372         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
373         if (rv < 0)
374                 goto out_xfrm46;
375         return 0;
376
377 out_xfrm46:
378         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
379 out_xfrm6:
380         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
381 out_type:
382         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
383 out_pernet:
384         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
385         return rv;
386 }
387
388 static void __exit xfrm6_tunnel_fini(void)
389 {
390         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
391         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
392         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
393         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
394         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
395 }
396
397 module_init(xfrm6_tunnel_init);
398 module_exit(xfrm6_tunnel_fini);
399 MODULE_LICENSE("GPL");
400 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);