Merge tag 'mmc-merge-for-3.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...
[pandora-kernel.git] / net / netfilter / nf_conntrack_proto.c
1 /* L3/L4 protocol support for nf_conntrack. */
2
3 /* (C) 1999-2001 Paul `Rusty' Russell
4  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
5  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11
12 #include <linux/types.h>
13 #include <linux/netfilter.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/mutex.h>
17 #include <linux/vmalloc.h>
18 #include <linux/stddef.h>
19 #include <linux/err.h>
20 #include <linux/percpu.h>
21 #include <linux/notifier.h>
22 #include <linux/kernel.h>
23 #include <linux/netdevice.h>
24 #include <linux/rtnetlink.h>
25
26 #include <net/netfilter/nf_conntrack.h>
27 #include <net/netfilter/nf_conntrack_l3proto.h>
28 #include <net/netfilter/nf_conntrack_l4proto.h>
29 #include <net/netfilter/nf_conntrack_core.h>
30
31 static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly;
32 struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly;
33 EXPORT_SYMBOL_GPL(nf_ct_l3protos);
34
35 static DEFINE_MUTEX(nf_ct_proto_mutex);
36
37 #ifdef CONFIG_SYSCTL
38 static int
39 nf_ct_register_sysctl(struct ctl_table_header **header, const char *path,
40                       struct ctl_table *table, unsigned int *users)
41 {
42         if (*header == NULL) {
43                 *header = register_net_sysctl(&init_net, path, table);
44                 if (*header == NULL)
45                         return -ENOMEM;
46         }
47         if (users != NULL)
48                 (*users)++;
49         return 0;
50 }
51
52 static void
53 nf_ct_unregister_sysctl(struct ctl_table_header **header,
54                         struct ctl_table *table, unsigned int *users)
55 {
56         if (users != NULL && --*users > 0)
57                 return;
58
59         unregister_net_sysctl_table(*header);
60         *header = NULL;
61 }
62 #endif
63
64 struct nf_conntrack_l4proto *
65 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
66 {
67         if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
68                 return &nf_conntrack_l4proto_generic;
69
70         return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
71 }
72 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
73
74 /* this is guaranteed to always return a valid protocol helper, since
75  * it falls back to generic_protocol */
76 struct nf_conntrack_l3proto *
77 nf_ct_l3proto_find_get(u_int16_t l3proto)
78 {
79         struct nf_conntrack_l3proto *p;
80
81         rcu_read_lock();
82         p = __nf_ct_l3proto_find(l3proto);
83         if (!try_module_get(p->me))
84                 p = &nf_conntrack_l3proto_generic;
85         rcu_read_unlock();
86
87         return p;
88 }
89 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
90
91 void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
92 {
93         module_put(p->me);
94 }
95 EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
96
97 int
98 nf_ct_l3proto_try_module_get(unsigned short l3proto)
99 {
100         int ret;
101         struct nf_conntrack_l3proto *p;
102
103 retry:  p = nf_ct_l3proto_find_get(l3proto);
104         if (p == &nf_conntrack_l3proto_generic) {
105                 ret = request_module("nf_conntrack-%d", l3proto);
106                 if (!ret)
107                         goto retry;
108
109                 return -EPROTOTYPE;
110         }
111
112         return 0;
113 }
114 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
115
116 void nf_ct_l3proto_module_put(unsigned short l3proto)
117 {
118         struct nf_conntrack_l3proto *p;
119
120         /* rcu_read_lock not necessary since the caller holds a reference, but
121          * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find()
122          */
123         rcu_read_lock();
124         p = __nf_ct_l3proto_find(l3proto);
125         module_put(p->me);
126         rcu_read_unlock();
127 }
128 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
129
130 struct nf_conntrack_l4proto *
131 nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num)
132 {
133         struct nf_conntrack_l4proto *p;
134
135         rcu_read_lock();
136         p = __nf_ct_l4proto_find(l3num, l4num);
137         if (!try_module_get(p->me))
138                 p = &nf_conntrack_l4proto_generic;
139         rcu_read_unlock();
140
141         return p;
142 }
143 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
144
145 void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
146 {
147         module_put(p->me);
148 }
149 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
150
151 static int kill_l3proto(struct nf_conn *i, void *data)
152 {
153         return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
154 }
155
156 static int kill_l4proto(struct nf_conn *i, void *data)
157 {
158         struct nf_conntrack_l4proto *l4proto;
159         l4proto = (struct nf_conntrack_l4proto *)data;
160         return nf_ct_protonum(i) == l4proto->l4proto &&
161                nf_ct_l3num(i) == l4proto->l3proto;
162 }
163
164 static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
165 {
166         int err = 0;
167
168 #ifdef CONFIG_SYSCTL
169         if (l3proto->ctl_table != NULL) {
170                 err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
171                                             l3proto->ctl_table_path,
172                                             l3proto->ctl_table, NULL);
173         }
174 #endif
175         return err;
176 }
177
178 static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
179 {
180 #ifdef CONFIG_SYSCTL
181         if (l3proto->ctl_table_header != NULL)
182                 nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
183                                         l3proto->ctl_table, NULL);
184 #endif
185 }
186
187 int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
188 {
189         int ret = 0;
190         struct nf_conntrack_l3proto *old;
191
192         if (proto->l3proto >= AF_MAX)
193                 return -EBUSY;
194
195         if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
196                 return -EINVAL;
197
198         mutex_lock(&nf_ct_proto_mutex);
199         old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
200                                         lockdep_is_held(&nf_ct_proto_mutex));
201         if (old != &nf_conntrack_l3proto_generic) {
202                 ret = -EBUSY;
203                 goto out_unlock;
204         }
205
206         ret = nf_ct_l3proto_register_sysctl(proto);
207         if (ret < 0)
208                 goto out_unlock;
209
210         if (proto->nlattr_tuple_size)
211                 proto->nla_size = 3 * proto->nlattr_tuple_size();
212
213         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
214
215 out_unlock:
216         mutex_unlock(&nf_ct_proto_mutex);
217         return ret;
218 }
219 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
220
221 void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
222 {
223         struct net *net;
224
225         BUG_ON(proto->l3proto >= AF_MAX);
226
227         mutex_lock(&nf_ct_proto_mutex);
228         BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
229                                          lockdep_is_held(&nf_ct_proto_mutex)
230                                          ) != proto);
231         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
232                            &nf_conntrack_l3proto_generic);
233         nf_ct_l3proto_unregister_sysctl(proto);
234         mutex_unlock(&nf_ct_proto_mutex);
235
236         synchronize_rcu();
237
238         /* Remove all contrack entries for this protocol */
239         rtnl_lock();
240         for_each_net(net)
241                 nf_ct_iterate_cleanup(net, kill_l3proto, proto);
242         rtnl_unlock();
243 }
244 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
245
246 static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
247 {
248         int err = 0;
249
250 #ifdef CONFIG_SYSCTL
251         if (l4proto->ctl_table != NULL) {
252                 err = nf_ct_register_sysctl(l4proto->ctl_table_header,
253                                             "net/netfilter",
254                                             l4proto->ctl_table,
255                                             l4proto->ctl_table_users);
256                 if (err < 0)
257                         goto out;
258         }
259 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
260         if (l4proto->ctl_compat_table != NULL) {
261                 err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
262                                             "net/ipv4/netfilter",
263                                             l4proto->ctl_compat_table, NULL);
264                 if (err == 0)
265                         goto out;
266                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
267                                         l4proto->ctl_table,
268                                         l4proto->ctl_table_users);
269         }
270 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
271 out:
272 #endif /* CONFIG_SYSCTL */
273         return err;
274 }
275
276 static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
277 {
278 #ifdef CONFIG_SYSCTL
279         if (l4proto->ctl_table_header != NULL &&
280             *l4proto->ctl_table_header != NULL)
281                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
282                                         l4proto->ctl_table,
283                                         l4proto->ctl_table_users);
284 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
285         if (l4proto->ctl_compat_table_header != NULL)
286                 nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
287                                         l4proto->ctl_compat_table, NULL);
288 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
289 #endif /* CONFIG_SYSCTL */
290 }
291
292 /* FIXME: Allow NULL functions and sub in pointers to generic for
293    them. --RR */
294 int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
295 {
296         int ret = 0;
297
298         if (l4proto->l3proto >= PF_MAX)
299                 return -EBUSY;
300
301         if ((l4proto->to_nlattr && !l4proto->nlattr_size)
302                 || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
303                 return -EINVAL;
304
305         mutex_lock(&nf_ct_proto_mutex);
306         if (!nf_ct_protos[l4proto->l3proto]) {
307                 /* l3proto may be loaded latter. */
308                 struct nf_conntrack_l4proto __rcu **proto_array;
309                 int i;
310
311                 proto_array = kmalloc(MAX_NF_CT_PROTO *
312                                       sizeof(struct nf_conntrack_l4proto *),
313                                       GFP_KERNEL);
314                 if (proto_array == NULL) {
315                         ret = -ENOMEM;
316                         goto out_unlock;
317                 }
318
319                 for (i = 0; i < MAX_NF_CT_PROTO; i++)
320                         RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic);
321
322                 /* Before making proto_array visible to lockless readers,
323                  * we must make sure its content is committed to memory.
324                  */
325                 smp_wmb();
326
327                 nf_ct_protos[l4proto->l3proto] = proto_array;
328         } else if (rcu_dereference_protected(
329                         nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
330                         lockdep_is_held(&nf_ct_proto_mutex)
331                         ) != &nf_conntrack_l4proto_generic) {
332                 ret = -EBUSY;
333                 goto out_unlock;
334         }
335
336         ret = nf_ct_l4proto_register_sysctl(l4proto);
337         if (ret < 0)
338                 goto out_unlock;
339
340         l4proto->nla_size = 0;
341         if (l4proto->nlattr_size)
342                 l4proto->nla_size += l4proto->nlattr_size();
343         if (l4proto->nlattr_tuple_size)
344                 l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();
345
346         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
347                            l4proto);
348
349 out_unlock:
350         mutex_unlock(&nf_ct_proto_mutex);
351         return ret;
352 }
353 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
354
355 void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
356 {
357         struct net *net;
358
359         BUG_ON(l4proto->l3proto >= PF_MAX);
360
361         mutex_lock(&nf_ct_proto_mutex);
362         BUG_ON(rcu_dereference_protected(
363                         nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
364                         lockdep_is_held(&nf_ct_proto_mutex)
365                         ) != l4proto);
366         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
367                            &nf_conntrack_l4proto_generic);
368         nf_ct_l4proto_unregister_sysctl(l4proto);
369         mutex_unlock(&nf_ct_proto_mutex);
370
371         synchronize_rcu();
372
373         /* Remove all contrack entries for this protocol */
374         rtnl_lock();
375         for_each_net(net)
376                 nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
377         rtnl_unlock();
378 }
379 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);
380
381 int nf_conntrack_proto_init(void)
382 {
383         unsigned int i;
384         int err;
385
386         err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
387         if (err < 0)
388                 return err;
389
390         for (i = 0; i < AF_MAX; i++)
391                 rcu_assign_pointer(nf_ct_l3protos[i],
392                                    &nf_conntrack_l3proto_generic);
393         return 0;
394 }
395
396 void nf_conntrack_proto_fini(void)
397 {
398         unsigned int i;
399
400         nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);
401
402         /* free l3proto protocol tables */
403         for (i = 0; i < PF_MAX; i++)
404                 kfree(nf_ct_protos[i]);
405 }