netfilter: don't use INIT_RCU_HEAD()
[linux-2.6.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/mutex.h>
16 #include <linux/skbuff.h>
17 #include <linux/vmalloc.h>
18 #include <linux/stddef.h>
19 #include <linux/err.h>
20 #include <linux/percpu.h>
21 #include <linux/moduleparam.h>
22 #include <linux/notifier.h>
23 #include <linux/kernel.h>
24 #include <linux/netdevice.h>
25 #include <linux/rtnetlink.h>
26
27 #include <net/netfilter/nf_conntrack.h>
28 #include <net/netfilter/nf_conntrack_l3proto.h>
29 #include <net/netfilter/nf_conntrack_l4proto.h>
30 #include <net/netfilter/nf_conntrack_core.h>
31
32 static struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly;
33 struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly;
34 EXPORT_SYMBOL_GPL(nf_ct_l3protos);
35
36 static DEFINE_MUTEX(nf_ct_proto_mutex);
37
38 #ifdef CONFIG_SYSCTL
39 static int
40 nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_path *path,
41                       struct ctl_table *table, unsigned int *users)
42 {
43         if (*header == NULL) {
44                 *header = register_sysctl_paths(path, table);
45                 if (*header == NULL)
46                         return -ENOMEM;
47         }
48         if (users != NULL)
49                 (*users)++;
50         return 0;
51 }
52
53 static void
54 nf_ct_unregister_sysctl(struct ctl_table_header **header,
55                         struct ctl_table *table, unsigned int *users)
56 {
57         if (users != NULL && --*users > 0)
58                 return;
59
60         unregister_sysctl_table(*header);
61         *header = NULL;
62 }
63 #endif
64
65 struct nf_conntrack_l4proto *
66 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
67 {
68         if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
69                 return &nf_conntrack_l4proto_generic;
70
71         return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
72 }
73 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
74
75 /* this is guaranteed to always return a valid protocol helper, since
76  * it falls back to generic_protocol */
77 struct nf_conntrack_l3proto *
78 nf_ct_l3proto_find_get(u_int16_t l3proto)
79 {
80         struct nf_conntrack_l3proto *p;
81
82         rcu_read_lock();
83         p = __nf_ct_l3proto_find(l3proto);
84         if (!try_module_get(p->me))
85                 p = &nf_conntrack_l3proto_generic;
86         rcu_read_unlock();
87
88         return p;
89 }
90 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
91
92 void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
93 {
94         module_put(p->me);
95 }
96 EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
97
98 int
99 nf_ct_l3proto_try_module_get(unsigned short l3proto)
100 {
101         int ret;
102         struct nf_conntrack_l3proto *p;
103
104 retry:  p = nf_ct_l3proto_find_get(l3proto);
105         if (p == &nf_conntrack_l3proto_generic) {
106                 ret = request_module("nf_conntrack-%d", l3proto);
107                 if (!ret)
108                         goto retry;
109
110                 return -EPROTOTYPE;
111         }
112
113         return 0;
114 }
115 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
116
117 void nf_ct_l3proto_module_put(unsigned short l3proto)
118 {
119         struct nf_conntrack_l3proto *p;
120
121         /* rcu_read_lock not necessary since the caller holds a reference */
122         p = __nf_ct_l3proto_find(l3proto);
123         module_put(p->me);
124 }
125 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
126
127 static int kill_l3proto(struct nf_conn *i, void *data)
128 {
129         return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
130 }
131
132 static int kill_l4proto(struct nf_conn *i, void *data)
133 {
134         struct nf_conntrack_l4proto *l4proto;
135         l4proto = (struct nf_conntrack_l4proto *)data;
136         return nf_ct_protonum(i) == l4proto->l4proto &&
137                nf_ct_l3num(i) == l4proto->l3proto;
138 }
139
140 static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
141 {
142         int err = 0;
143
144 #ifdef CONFIG_SYSCTL
145         if (l3proto->ctl_table != NULL) {
146                 err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
147                                             l3proto->ctl_table_path,
148                                             l3proto->ctl_table, NULL);
149         }
150 #endif
151         return err;
152 }
153
154 static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
155 {
156 #ifdef CONFIG_SYSCTL
157         if (l3proto->ctl_table_header != NULL)
158                 nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
159                                         l3proto->ctl_table, NULL);
160 #endif
161 }
162
163 int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
164 {
165         int ret = 0;
166
167         if (proto->l3proto >= AF_MAX)
168                 return -EBUSY;
169
170         if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
171                 return -EINVAL;
172
173         mutex_lock(&nf_ct_proto_mutex);
174         if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
175                 ret = -EBUSY;
176                 goto out_unlock;
177         }
178
179         ret = nf_ct_l3proto_register_sysctl(proto);
180         if (ret < 0)
181                 goto out_unlock;
182
183         if (proto->nlattr_tuple_size)
184                 proto->nla_size = 3 * proto->nlattr_tuple_size();
185
186         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
187
188 out_unlock:
189         mutex_unlock(&nf_ct_proto_mutex);
190         return ret;
191 }
192 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
193
194 void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
195 {
196         struct net *net;
197
198         BUG_ON(proto->l3proto >= AF_MAX);
199
200         mutex_lock(&nf_ct_proto_mutex);
201         BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
202         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
203                            &nf_conntrack_l3proto_generic);
204         nf_ct_l3proto_unregister_sysctl(proto);
205         mutex_unlock(&nf_ct_proto_mutex);
206
207         synchronize_rcu();
208
209         /* Remove all contrack entries for this protocol */
210         rtnl_lock();
211         for_each_net(net)
212                 nf_ct_iterate_cleanup(net, kill_l3proto, proto);
213         rtnl_unlock();
214 }
215 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
216
217 static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
218 {
219         int err = 0;
220
221 #ifdef CONFIG_SYSCTL
222         if (l4proto->ctl_table != NULL) {
223                 err = nf_ct_register_sysctl(l4proto->ctl_table_header,
224                                             nf_net_netfilter_sysctl_path,
225                                             l4proto->ctl_table,
226                                             l4proto->ctl_table_users);
227                 if (err < 0)
228                         goto out;
229         }
230 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
231         if (l4proto->ctl_compat_table != NULL) {
232                 err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
233                                             nf_net_ipv4_netfilter_sysctl_path,
234                                             l4proto->ctl_compat_table, NULL);
235                 if (err == 0)
236                         goto out;
237                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
238                                         l4proto->ctl_table,
239                                         l4proto->ctl_table_users);
240         }
241 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
242 out:
243 #endif /* CONFIG_SYSCTL */
244         return err;
245 }
246
247 static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
248 {
249 #ifdef CONFIG_SYSCTL
250         if (l4proto->ctl_table_header != NULL &&
251             *l4proto->ctl_table_header != NULL)
252                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
253                                         l4proto->ctl_table,
254                                         l4proto->ctl_table_users);
255 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
256         if (l4proto->ctl_compat_table_header != NULL)
257                 nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
258                                         l4proto->ctl_compat_table, NULL);
259 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
260 #endif /* CONFIG_SYSCTL */
261 }
262
263 /* FIXME: Allow NULL functions and sub in pointers to generic for
264    them. --RR */
265 int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
266 {
267         int ret = 0;
268
269         if (l4proto->l3proto >= PF_MAX)
270                 return -EBUSY;
271
272         if ((l4proto->to_nlattr && !l4proto->nlattr_size)
273                 || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
274                 return -EINVAL;
275
276         mutex_lock(&nf_ct_proto_mutex);
277         if (!nf_ct_protos[l4proto->l3proto]) {
278                 /* l3proto may be loaded latter. */
279                 struct nf_conntrack_l4proto **proto_array;
280                 int i;
281
282                 proto_array = kmalloc(MAX_NF_CT_PROTO *
283                                       sizeof(struct nf_conntrack_l4proto *),
284                                       GFP_KERNEL);
285                 if (proto_array == NULL) {
286                         ret = -ENOMEM;
287                         goto out_unlock;
288                 }
289
290                 for (i = 0; i < MAX_NF_CT_PROTO; i++)
291                         proto_array[i] = &nf_conntrack_l4proto_generic;
292                 nf_ct_protos[l4proto->l3proto] = proto_array;
293         } else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] !=
294                                         &nf_conntrack_l4proto_generic) {
295                 ret = -EBUSY;
296                 goto out_unlock;
297         }
298
299         ret = nf_ct_l4proto_register_sysctl(l4proto);
300         if (ret < 0)
301                 goto out_unlock;
302
303         l4proto->nla_size = 0;
304         if (l4proto->nlattr_size)
305                 l4proto->nla_size += l4proto->nlattr_size();
306         if (l4proto->nlattr_tuple_size)
307                 l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();
308
309         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
310                            l4proto);
311
312 out_unlock:
313         mutex_unlock(&nf_ct_proto_mutex);
314         return ret;
315 }
316 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
317
318 void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
319 {
320         struct net *net;
321
322         BUG_ON(l4proto->l3proto >= PF_MAX);
323
324         mutex_lock(&nf_ct_proto_mutex);
325         BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
326         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
327                            &nf_conntrack_l4proto_generic);
328         nf_ct_l4proto_unregister_sysctl(l4proto);
329         mutex_unlock(&nf_ct_proto_mutex);
330
331         synchronize_rcu();
332
333         /* Remove all contrack entries for this protocol */
334         rtnl_lock();
335         for_each_net(net)
336                 nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
337         rtnl_unlock();
338 }
339 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);
340
341 int nf_conntrack_proto_init(void)
342 {
343         unsigned int i;
344         int err;
345
346         err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
347         if (err < 0)
348                 return err;
349
350         for (i = 0; i < AF_MAX; i++)
351                 rcu_assign_pointer(nf_ct_l3protos[i],
352                                    &nf_conntrack_l3proto_generic);
353         return 0;
354 }
355
356 void nf_conntrack_proto_fini(void)
357 {
358         unsigned int i;
359
360         nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);
361
362         /* free l3proto protocol tables */
363         for (i = 0; i < PF_MAX; i++)
364                 kfree(nf_ct_protos[i]);
365 }