xfrm6_tunnel: RCU conversion
[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
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         struct rcu_head         rcu_head;
45 };
46
47 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
48
49 static u32 xfrm6_tunnel_spi;
50
51 #define XFRM6_TUNNEL_SPI_MIN    1
52 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
53
54 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
55
56 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
57 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
58
59 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
60 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
61
62 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
63 {
64         unsigned h;
65
66         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
67         h ^= h >> 16;
68         h ^= h >> 8;
69         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
70
71         return h;
72 }
73
74 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
75 {
76         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
77 }
78
79
80 static int xfrm6_tunnel_spi_init(void)
81 {
82         int i;
83
84         xfrm6_tunnel_spi = 0;
85         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
86                                                   sizeof(struct xfrm6_tunnel_spi),
87                                                   0, SLAB_HWCACHE_ALIGN,
88                                                   NULL);
89         if (!xfrm6_tunnel_spi_kmem)
90                 return -ENOMEM;
91
92         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
93                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
94         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
95                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
96         return 0;
97 }
98
99 static void xfrm6_tunnel_spi_fini(void)
100 {
101         int i;
102
103         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
104                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
105                         return;
106         }
107         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
108                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
109                         return;
110         }
111         rcu_barrier();
112         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
113         xfrm6_tunnel_spi_kmem = NULL;
114 }
115
116 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
117 {
118         struct xfrm6_tunnel_spi *x6spi;
119         struct hlist_node *pos;
120
121         hlist_for_each_entry_rcu(x6spi, pos,
122                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
123                              list_byaddr) {
124                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
125                         return x6spi;
126         }
127
128         return NULL;
129 }
130
131 __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
132 {
133         struct xfrm6_tunnel_spi *x6spi;
134         u32 spi;
135
136         rcu_read_lock_bh();
137         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
138         spi = x6spi ? x6spi->spi : 0;
139         rcu_read_unlock_bh();
140         return htonl(spi);
141 }
142
143 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
144
145 static int __xfrm6_tunnel_spi_check(u32 spi)
146 {
147         struct xfrm6_tunnel_spi *x6spi;
148         int index = xfrm6_tunnel_spi_hash_byspi(spi);
149         struct hlist_node *pos;
150
151         hlist_for_each_entry(x6spi, pos,
152                              &xfrm6_tunnel_spi_byspi[index],
153                              list_byspi) {
154                 if (x6spi->spi == spi)
155                         return -1;
156         }
157         return index;
158 }
159
160 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
161 {
162         u32 spi;
163         struct xfrm6_tunnel_spi *x6spi;
164         int index;
165
166         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
167             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
168                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
169         else
170                 xfrm6_tunnel_spi++;
171
172         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
173                 index = __xfrm6_tunnel_spi_check(spi);
174                 if (index >= 0)
175                         goto alloc_spi;
176         }
177         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
178                 index = __xfrm6_tunnel_spi_check(spi);
179                 if (index >= 0)
180                         goto alloc_spi;
181         }
182         spi = 0;
183         goto out;
184 alloc_spi:
185         xfrm6_tunnel_spi = spi;
186         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
187         if (!x6spi)
188                 goto out;
189
190         INIT_RCU_HEAD(&x6spi->rcu_head);
191         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
192         x6spi->spi = spi;
193         atomic_set(&x6spi->refcnt, 1);
194
195         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
196
197         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
198         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
199 out:
200         return spi;
201 }
202
203 __be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
204 {
205         struct xfrm6_tunnel_spi *x6spi;
206         u32 spi;
207
208         spin_lock_bh(&xfrm6_tunnel_spi_lock);
209         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
210         if (x6spi) {
211                 atomic_inc(&x6spi->refcnt);
212                 spi = x6spi->spi;
213         } else
214                 spi = __xfrm6_tunnel_alloc_spi(saddr);
215         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
216
217         return htonl(spi);
218 }
219
220 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
221
222 static void x6spi_destroy_rcu(struct rcu_head *head)
223 {
224         kmem_cache_free(xfrm6_tunnel_spi_kmem,
225                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
226 }
227
228 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
229 {
230         struct xfrm6_tunnel_spi *x6spi;
231         struct hlist_node *pos, *n;
232
233         spin_lock_bh(&xfrm6_tunnel_spi_lock);
234
235         hlist_for_each_entry_safe(x6spi, pos, n,
236                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
237                                   list_byaddr)
238         {
239                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
240                         if (atomic_dec_and_test(&x6spi->refcnt)) {
241                                 hlist_del_rcu(&x6spi->list_byaddr);
242                                 hlist_del_rcu(&x6spi->list_byspi);
243                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
244                                 break;
245                         }
246                 }
247         }
248         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
249 }
250
251 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
252
253 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
254 {
255         skb_push(skb, -skb_network_offset(skb));
256         return 0;
257 }
258
259 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
260 {
261         return skb_network_header(skb)[IP6CB(skb)->nhoff];
262 }
263
264 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
265 {
266         struct ipv6hdr *iph = ipv6_hdr(skb);
267         __be32 spi;
268
269         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
270         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
271 }
272
273 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
274                             u8 type, u8 code, int offset, __be32 info)
275 {
276         /* xfrm6_tunnel native err handling */
277         switch (type) {
278         case ICMPV6_DEST_UNREACH:
279                 switch (code) {
280                 case ICMPV6_NOROUTE:
281                 case ICMPV6_ADM_PROHIBITED:
282                 case ICMPV6_NOT_NEIGHBOUR:
283                 case ICMPV6_ADDR_UNREACH:
284                 case ICMPV6_PORT_UNREACH:
285                 default:
286                         break;
287                 }
288                 break;
289         case ICMPV6_PKT_TOOBIG:
290                 break;
291         case ICMPV6_TIME_EXCEED:
292                 switch (code) {
293                 case ICMPV6_EXC_HOPLIMIT:
294                         break;
295                 case ICMPV6_EXC_FRAGTIME:
296                 default:
297                         break;
298                 }
299                 break;
300         case ICMPV6_PARAMPROB:
301                 switch (code) {
302                 case ICMPV6_HDR_FIELD: break;
303                 case ICMPV6_UNK_NEXTHDR: break;
304                 case ICMPV6_UNK_OPTION: break;
305                 }
306                 break;
307         default:
308                 break;
309         }
310
311         return 0;
312 }
313
314 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
315 {
316         if (x->props.mode != XFRM_MODE_TUNNEL)
317                 return -EINVAL;
318
319         if (x->encap)
320                 return -EINVAL;
321
322         x->props.header_len = sizeof(struct ipv6hdr);
323
324         return 0;
325 }
326
327 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
328 {
329         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
330 }
331
332 static const struct xfrm_type xfrm6_tunnel_type = {
333         .description    = "IP6IP6",
334         .owner          = THIS_MODULE,
335         .proto          = IPPROTO_IPV6,
336         .init_state     = xfrm6_tunnel_init_state,
337         .destructor     = xfrm6_tunnel_destroy,
338         .input          = xfrm6_tunnel_input,
339         .output         = xfrm6_tunnel_output,
340 };
341
342 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
343         .handler        = xfrm6_tunnel_rcv,
344         .err_handler    = xfrm6_tunnel_err,
345         .priority       = 2,
346 };
347
348 static struct xfrm6_tunnel xfrm46_tunnel_handler = {
349         .handler        = xfrm6_tunnel_rcv,
350         .err_handler    = xfrm6_tunnel_err,
351         .priority       = 2,
352 };
353
354 static int __init xfrm6_tunnel_init(void)
355 {
356         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0)
357                 goto err;
358         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6))
359                 goto unreg;
360         if (xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET))
361                 goto dereg6;
362         if (xfrm6_tunnel_spi_init() < 0)
363                 goto dereg46;
364         return 0;
365
366 dereg46:
367         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
368 dereg6:
369         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
370 unreg:
371         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
372 err:
373         return -EAGAIN;
374 }
375
376 static void __exit xfrm6_tunnel_fini(void)
377 {
378         xfrm6_tunnel_spi_fini();
379         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
380         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
381         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
382 }
383
384 module_init(xfrm6_tunnel_init);
385 module_exit(xfrm6_tunnel_fini);
386 MODULE_LICENSE("GPL");
387 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);