netns xfrm: xfrm6_tunnel in netns
[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/rculist.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 #include <net/netns/generic.h>
34
35 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
36 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
37
38 #define XFRM6_TUNNEL_SPI_MIN    1
39 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
40
41 struct xfrm6_tunnel_net {
42         struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
43         struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
44         u32 spi;
45 };
46
47 static int xfrm6_tunnel_net_id __read_mostly;
48 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
49 {
50         return net_generic(net, xfrm6_tunnel_net_id);
51 }
52
53 /*
54  * xfrm_tunnel_spi things are for allocating unique id ("spi")
55  * per xfrm_address_t.
56  */
57 struct xfrm6_tunnel_spi {
58         struct hlist_node       list_byaddr;
59         struct hlist_node       list_byspi;
60         xfrm_address_t          addr;
61         u32                     spi;
62         atomic_t                refcnt;
63         struct rcu_head         rcu_head;
64 };
65
66 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
67
68 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
69
70 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
71 {
72         unsigned h;
73
74         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
75         h ^= h >> 16;
76         h ^= h >> 8;
77         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
78
79         return h;
80 }
81
82 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
83 {
84         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
85 }
86
87
88 static int __init xfrm6_tunnel_spi_init(void)
89 {
90         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
91                                                   sizeof(struct xfrm6_tunnel_spi),
92                                                   0, SLAB_HWCACHE_ALIGN,
93                                                   NULL);
94         if (!xfrm6_tunnel_spi_kmem)
95                 return -ENOMEM;
96         return 0;
97 }
98
99 static void xfrm6_tunnel_spi_fini(void)
100 {
101         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
102 }
103
104 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
105 {
106         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
107         struct xfrm6_tunnel_spi *x6spi;
108         struct hlist_node *pos;
109
110         hlist_for_each_entry_rcu(x6spi, pos,
111                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
112                              list_byaddr) {
113                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
114                         return x6spi;
115         }
116
117         return NULL;
118 }
119
120 __be32 xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
121 {
122         struct xfrm6_tunnel_spi *x6spi;
123         u32 spi;
124
125         rcu_read_lock_bh();
126         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
127         spi = x6spi ? x6spi->spi : 0;
128         rcu_read_unlock_bh();
129         return htonl(spi);
130 }
131
132 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
133
134 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
135 {
136         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
137         struct xfrm6_tunnel_spi *x6spi;
138         int index = xfrm6_tunnel_spi_hash_byspi(spi);
139         struct hlist_node *pos;
140
141         hlist_for_each_entry(x6spi, pos,
142                              &xfrm6_tn->spi_byspi[index],
143                              list_byspi) {
144                 if (x6spi->spi == spi)
145                         return -1;
146         }
147         return index;
148 }
149
150 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
151 {
152         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
153         u32 spi;
154         struct xfrm6_tunnel_spi *x6spi;
155         int index;
156
157         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
158             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
159                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
160         else
161                 xfrm6_tn->spi++;
162
163         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
164                 index = __xfrm6_tunnel_spi_check(net, spi);
165                 if (index >= 0)
166                         goto alloc_spi;
167         }
168         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
169                 index = __xfrm6_tunnel_spi_check(net, spi);
170                 if (index >= 0)
171                         goto alloc_spi;
172         }
173         spi = 0;
174         goto out;
175 alloc_spi:
176         xfrm6_tn->spi = spi;
177         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
178         if (!x6spi)
179                 goto out;
180
181         INIT_RCU_HEAD(&x6spi->rcu_head);
182         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
183         x6spi->spi = spi;
184         atomic_set(&x6spi->refcnt, 1);
185
186         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
187
188         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
189         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
190 out:
191         return spi;
192 }
193
194 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
195 {
196         struct xfrm6_tunnel_spi *x6spi;
197         u32 spi;
198
199         spin_lock_bh(&xfrm6_tunnel_spi_lock);
200         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
201         if (x6spi) {
202                 atomic_inc(&x6spi->refcnt);
203                 spi = x6spi->spi;
204         } else
205                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
206         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
207
208         return htonl(spi);
209 }
210
211 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
212
213 static void x6spi_destroy_rcu(struct rcu_head *head)
214 {
215         kmem_cache_free(xfrm6_tunnel_spi_kmem,
216                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
217 }
218
219 void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
220 {
221         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
222         struct xfrm6_tunnel_spi *x6spi;
223         struct hlist_node *pos, *n;
224
225         spin_lock_bh(&xfrm6_tunnel_spi_lock);
226
227         hlist_for_each_entry_safe(x6spi, pos, n,
228                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
229                                   list_byaddr)
230         {
231                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
232                         if (atomic_dec_and_test(&x6spi->refcnt)) {
233                                 hlist_del_rcu(&x6spi->list_byaddr);
234                                 hlist_del_rcu(&x6spi->list_byspi);
235                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
236                                 break;
237                         }
238                 }
239         }
240         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
241 }
242
243 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
244
245 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
246 {
247         skb_push(skb, -skb_network_offset(skb));
248         return 0;
249 }
250
251 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
252 {
253         return skb_network_header(skb)[IP6CB(skb)->nhoff];
254 }
255
256 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
257 {
258         struct net *net = dev_net(skb->dev);
259         struct ipv6hdr *iph = ipv6_hdr(skb);
260         __be32 spi;
261
262         spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&iph->saddr);
263         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
264 }
265
266 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
267                             u8 type, u8 code, int offset, __be32 info)
268 {
269         /* xfrm6_tunnel native err handling */
270         switch (type) {
271         case ICMPV6_DEST_UNREACH:
272                 switch (code) {
273                 case ICMPV6_NOROUTE:
274                 case ICMPV6_ADM_PROHIBITED:
275                 case ICMPV6_NOT_NEIGHBOUR:
276                 case ICMPV6_ADDR_UNREACH:
277                 case ICMPV6_PORT_UNREACH:
278                 default:
279                         break;
280                 }
281                 break;
282         case ICMPV6_PKT_TOOBIG:
283                 break;
284         case ICMPV6_TIME_EXCEED:
285                 switch (code) {
286                 case ICMPV6_EXC_HOPLIMIT:
287                         break;
288                 case ICMPV6_EXC_FRAGTIME:
289                 default:
290                         break;
291                 }
292                 break;
293         case ICMPV6_PARAMPROB:
294                 switch (code) {
295                 case ICMPV6_HDR_FIELD: break;
296                 case ICMPV6_UNK_NEXTHDR: break;
297                 case ICMPV6_UNK_OPTION: break;
298                 }
299                 break;
300         default:
301                 break;
302         }
303
304         return 0;
305 }
306
307 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
308 {
309         if (x->props.mode != XFRM_MODE_TUNNEL)
310                 return -EINVAL;
311
312         if (x->encap)
313                 return -EINVAL;
314
315         x->props.header_len = sizeof(struct ipv6hdr);
316
317         return 0;
318 }
319
320 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
321 {
322         struct net *net = xs_net(x);
323
324         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
325 }
326
327 static const struct xfrm_type xfrm6_tunnel_type = {
328         .description    = "IP6IP6",
329         .owner          = THIS_MODULE,
330         .proto          = IPPROTO_IPV6,
331         .init_state     = xfrm6_tunnel_init_state,
332         .destructor     = xfrm6_tunnel_destroy,
333         .input          = xfrm6_tunnel_input,
334         .output         = xfrm6_tunnel_output,
335 };
336
337 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
338         .handler        = xfrm6_tunnel_rcv,
339         .err_handler    = xfrm6_tunnel_err,
340         .priority       = 2,
341 };
342
343 static struct xfrm6_tunnel xfrm46_tunnel_handler = {
344         .handler        = xfrm6_tunnel_rcv,
345         .err_handler    = xfrm6_tunnel_err,
346         .priority       = 2,
347 };
348
349 static int __net_init xfrm6_tunnel_net_init(struct net *net)
350 {
351         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
352         unsigned int i;
353
354         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
355                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
356         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
357                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
358         xfrm6_tn->spi = 0;
359
360         return 0;
361 }
362
363 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
364 {
365 }
366
367 static struct pernet_operations xfrm6_tunnel_net_ops = {
368         .init   = xfrm6_tunnel_net_init,
369         .exit   = xfrm6_tunnel_net_exit,
370         .id     = &xfrm6_tunnel_net_id,
371         .size   = sizeof(struct xfrm6_tunnel_net),
372 };
373
374 static int __init xfrm6_tunnel_init(void)
375 {
376         int rv;
377
378         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
379         if (rv < 0)
380                 goto err;
381         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
382         if (rv < 0)
383                 goto unreg;
384         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
385         if (rv < 0)
386                 goto dereg6;
387         rv = xfrm6_tunnel_spi_init();
388         if (rv < 0)
389                 goto dereg46;
390         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
391         if (rv < 0)
392                 goto deregspi;
393         return 0;
394
395 deregspi:
396         xfrm6_tunnel_spi_fini();
397 dereg46:
398         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
399 dereg6:
400         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
401 unreg:
402         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
403 err:
404         return rv;
405 }
406
407 static void __exit xfrm6_tunnel_fini(void)
408 {
409         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
410         xfrm6_tunnel_spi_fini();
411         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
412         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
413         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
414 }
415
416 module_init(xfrm6_tunnel_init);
417 module_exit(xfrm6_tunnel_fini);
418 MODULE_LICENSE("GPL");
419 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);