Phonet: basic net namespace support
[linux-3.10.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_l4proto *
78 nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
79 {
80         struct nf_conntrack_l4proto *p;
81
82         rcu_read_lock();
83         p = __nf_ct_l4proto_find(l3proto, l4proto);
84         if (!try_module_get(p->me))
85                 p = &nf_conntrack_l4proto_generic;
86         rcu_read_unlock();
87
88         return p;
89 }
90 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
91
92 void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
93 {
94         module_put(p->me);
95 }
96 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
97
98 struct nf_conntrack_l3proto *
99 nf_ct_l3proto_find_get(u_int16_t l3proto)
100 {
101         struct nf_conntrack_l3proto *p;
102
103         rcu_read_lock();
104         p = __nf_ct_l3proto_find(l3proto);
105         if (!try_module_get(p->me))
106                 p = &nf_conntrack_l3proto_generic;
107         rcu_read_unlock();
108
109         return p;
110 }
111 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
112
113 void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
114 {
115         module_put(p->me);
116 }
117 EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
118
119 int
120 nf_ct_l3proto_try_module_get(unsigned short l3proto)
121 {
122         int ret;
123         struct nf_conntrack_l3proto *p;
124
125 retry:  p = nf_ct_l3proto_find_get(l3proto);
126         if (p == &nf_conntrack_l3proto_generic) {
127                 ret = request_module("nf_conntrack-%d", l3proto);
128                 if (!ret)
129                         goto retry;
130
131                 return -EPROTOTYPE;
132         }
133
134         return 0;
135 }
136 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
137
138 void nf_ct_l3proto_module_put(unsigned short l3proto)
139 {
140         struct nf_conntrack_l3proto *p;
141
142         /* rcu_read_lock not necessary since the caller holds a reference */
143         p = __nf_ct_l3proto_find(l3proto);
144         module_put(p->me);
145 }
146 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
147
148 static int kill_l3proto(struct nf_conn *i, void *data)
149 {
150         return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
151 }
152
153 static int kill_l4proto(struct nf_conn *i, void *data)
154 {
155         struct nf_conntrack_l4proto *l4proto;
156         l4proto = (struct nf_conntrack_l4proto *)data;
157         return nf_ct_protonum(i) == l4proto->l4proto &&
158                nf_ct_l3num(i) == l4proto->l3proto;
159 }
160
161 static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
162 {
163         int err = 0;
164
165 #ifdef CONFIG_SYSCTL
166         if (l3proto->ctl_table != NULL) {
167                 err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
168                                             l3proto->ctl_table_path,
169                                             l3proto->ctl_table, NULL);
170         }
171 #endif
172         return err;
173 }
174
175 static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
176 {
177 #ifdef CONFIG_SYSCTL
178         if (l3proto->ctl_table_header != NULL)
179                 nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
180                                         l3proto->ctl_table, NULL);
181 #endif
182 }
183
184 int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
185 {
186         int ret = 0;
187
188         if (proto->l3proto >= AF_MAX)
189                 return -EBUSY;
190
191         mutex_lock(&nf_ct_proto_mutex);
192         if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
193                 ret = -EBUSY;
194                 goto out_unlock;
195         }
196
197         ret = nf_ct_l3proto_register_sysctl(proto);
198         if (ret < 0)
199                 goto out_unlock;
200
201         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
202
203 out_unlock:
204         mutex_unlock(&nf_ct_proto_mutex);
205         return ret;
206 }
207 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
208
209 void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
210 {
211         struct net *net;
212
213         BUG_ON(proto->l3proto >= AF_MAX);
214
215         mutex_lock(&nf_ct_proto_mutex);
216         BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
217         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
218                            &nf_conntrack_l3proto_generic);
219         nf_ct_l3proto_unregister_sysctl(proto);
220         mutex_unlock(&nf_ct_proto_mutex);
221
222         synchronize_rcu();
223
224         /* Remove all contrack entries for this protocol */
225         rtnl_lock();
226         for_each_net(net)
227                 nf_ct_iterate_cleanup(net, kill_l3proto, proto);
228         rtnl_unlock();
229 }
230 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
231
232 static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
233 {
234         int err = 0;
235
236 #ifdef CONFIG_SYSCTL
237         if (l4proto->ctl_table != NULL) {
238                 err = nf_ct_register_sysctl(l4proto->ctl_table_header,
239                                             nf_net_netfilter_sysctl_path,
240                                             l4proto->ctl_table,
241                                             l4proto->ctl_table_users);
242                 if (err < 0)
243                         goto out;
244         }
245 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
246         if (l4proto->ctl_compat_table != NULL) {
247                 err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
248                                             nf_net_ipv4_netfilter_sysctl_path,
249                                             l4proto->ctl_compat_table, NULL);
250                 if (err == 0)
251                         goto out;
252                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
253                                         l4proto->ctl_table,
254                                         l4proto->ctl_table_users);
255         }
256 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
257 out:
258 #endif /* CONFIG_SYSCTL */
259         return err;
260 }
261
262 static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
263 {
264 #ifdef CONFIG_SYSCTL
265         if (l4proto->ctl_table_header != NULL &&
266             *l4proto->ctl_table_header != NULL)
267                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
268                                         l4proto->ctl_table,
269                                         l4proto->ctl_table_users);
270 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
271         if (l4proto->ctl_compat_table_header != NULL)
272                 nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
273                                         l4proto->ctl_compat_table, NULL);
274 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
275 #endif /* CONFIG_SYSCTL */
276 }
277
278 /* FIXME: Allow NULL functions and sub in pointers to generic for
279    them. --RR */
280 int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
281 {
282         int ret = 0;
283
284         if (l4proto->l3proto >= PF_MAX)
285                 return -EBUSY;
286
287         mutex_lock(&nf_ct_proto_mutex);
288         if (!nf_ct_protos[l4proto->l3proto]) {
289                 /* l3proto may be loaded latter. */
290                 struct nf_conntrack_l4proto **proto_array;
291                 int i;
292
293                 proto_array = kmalloc(MAX_NF_CT_PROTO *
294                                       sizeof(struct nf_conntrack_l4proto *),
295                                       GFP_KERNEL);
296                 if (proto_array == NULL) {
297                         ret = -ENOMEM;
298                         goto out_unlock;
299                 }
300
301                 for (i = 0; i < MAX_NF_CT_PROTO; i++)
302                         proto_array[i] = &nf_conntrack_l4proto_generic;
303                 nf_ct_protos[l4proto->l3proto] = proto_array;
304         } else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] !=
305                                         &nf_conntrack_l4proto_generic) {
306                 ret = -EBUSY;
307                 goto out_unlock;
308         }
309
310         ret = nf_ct_l4proto_register_sysctl(l4proto);
311         if (ret < 0)
312                 goto out_unlock;
313
314         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
315                            l4proto);
316
317 out_unlock:
318         mutex_unlock(&nf_ct_proto_mutex);
319         return ret;
320 }
321 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
322
323 void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
324 {
325         struct net *net;
326
327         BUG_ON(l4proto->l3proto >= PF_MAX);
328
329         mutex_lock(&nf_ct_proto_mutex);
330         BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
331         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
332                            &nf_conntrack_l4proto_generic);
333         nf_ct_l4proto_unregister_sysctl(l4proto);
334         mutex_unlock(&nf_ct_proto_mutex);
335
336         synchronize_rcu();
337
338         /* Remove all contrack entries for this protocol */
339         rtnl_lock();
340         for_each_net(net)
341                 nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
342         rtnl_unlock();
343 }
344 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);
345
346 int nf_conntrack_proto_init(void)
347 {
348         unsigned int i;
349         int err;
350
351         err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
352         if (err < 0)
353                 return err;
354
355         for (i = 0; i < AF_MAX; i++)
356                 rcu_assign_pointer(nf_ct_l3protos[i],
357                                    &nf_conntrack_l3proto_generic);
358         return 0;
359 }
360
361 void nf_conntrack_proto_fini(void)
362 {
363         unsigned int i;
364
365         nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);
366
367         /* free l3proto protocol tables */
368         for (i = 0; i < PF_MAX; i++)
369                 kfree(nf_ct_protos[i]);
370 }