[NETFILTER]: nf_conntrack: use bool type in struct nf_conntrack_l3proto
[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
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 **nf_ct_protos[PF_MAX] __read_mostly;
32 struct nf_conntrack_l3proto *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, struct ctl_path *path,
40                       struct ctl_table *table, unsigned int *users)
41 {
42         if (*header == NULL) {
43                 *header = register_sysctl_paths(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_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_l4proto *
77 nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
78 {
79         struct nf_conntrack_l4proto *p;
80
81         rcu_read_lock();
82         p = __nf_ct_l4proto_find(l3proto, l4proto);
83         if (!try_module_get(p->me))
84                 p = &nf_conntrack_l4proto_generic;
85         rcu_read_unlock();
86
87         return p;
88 }
89 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
90
91 void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
92 {
93         module_put(p->me);
94 }
95 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
96
97 struct nf_conntrack_l3proto *
98 nf_ct_l3proto_find_get(u_int16_t l3proto)
99 {
100         struct nf_conntrack_l3proto *p;
101
102         rcu_read_lock();
103         p = __nf_ct_l3proto_find(l3proto);
104         if (!try_module_get(p->me))
105                 p = &nf_conntrack_l3proto_generic;
106         rcu_read_unlock();
107
108         return p;
109 }
110 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
111
112 void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
113 {
114         module_put(p->me);
115 }
116 EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
117
118 int
119 nf_ct_l3proto_try_module_get(unsigned short l3proto)
120 {
121         int ret;
122         struct nf_conntrack_l3proto *p;
123
124 retry:  p = nf_ct_l3proto_find_get(l3proto);
125         if (p == &nf_conntrack_l3proto_generic) {
126                 ret = request_module("nf_conntrack-%d", l3proto);
127                 if (!ret)
128                         goto retry;
129
130                 return -EPROTOTYPE;
131         }
132
133         return 0;
134 }
135 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
136
137 void nf_ct_l3proto_module_put(unsigned short l3proto)
138 {
139         struct nf_conntrack_l3proto *p;
140
141         /* rcu_read_lock not necessary since the caller holds a reference */
142         p = __nf_ct_l3proto_find(l3proto);
143         module_put(p->me);
144 }
145 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
146
147 static int kill_l3proto(struct nf_conn *i, void *data)
148 {
149         return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
150 }
151
152 static int kill_l4proto(struct nf_conn *i, void *data)
153 {
154         struct nf_conntrack_l4proto *l4proto;
155         l4proto = (struct nf_conntrack_l4proto *)data;
156         return nf_ct_protonum(i) == l4proto->l4proto &&
157                nf_ct_l3num(i) == l4proto->l3proto;
158 }
159
160 static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
161 {
162         int err = 0;
163
164 #ifdef CONFIG_SYSCTL
165         if (l3proto->ctl_table != NULL) {
166                 err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
167                                             l3proto->ctl_table_path,
168                                             l3proto->ctl_table, NULL);
169         }
170 #endif
171         return err;
172 }
173
174 static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
175 {
176 #ifdef CONFIG_SYSCTL
177         if (l3proto->ctl_table_header != NULL)
178                 nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
179                                         l3proto->ctl_table, NULL);
180 #endif
181 }
182
183 int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
184 {
185         int ret = 0;
186
187         if (proto->l3proto >= AF_MAX)
188                 return -EBUSY;
189
190         mutex_lock(&nf_ct_proto_mutex);
191         if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
192                 ret = -EBUSY;
193                 goto out_unlock;
194         }
195
196         ret = nf_ct_l3proto_register_sysctl(proto);
197         if (ret < 0)
198                 goto out_unlock;
199
200         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
201
202 out_unlock:
203         mutex_unlock(&nf_ct_proto_mutex);
204         return ret;
205 }
206 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
207
208 void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
209 {
210         BUG_ON(proto->l3proto >= AF_MAX);
211
212         mutex_lock(&nf_ct_proto_mutex);
213         BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
214         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
215                            &nf_conntrack_l3proto_generic);
216         nf_ct_l3proto_unregister_sysctl(proto);
217         mutex_unlock(&nf_ct_proto_mutex);
218
219         synchronize_rcu();
220
221         /* Remove all contrack entries for this protocol */
222         nf_ct_iterate_cleanup(kill_l3proto, proto);
223 }
224 EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
225
226 static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
227 {
228         int err = 0;
229
230 #ifdef CONFIG_SYSCTL
231         if (l4proto->ctl_table != NULL) {
232                 err = nf_ct_register_sysctl(l4proto->ctl_table_header,
233                                             nf_net_netfilter_sysctl_path,
234                                             l4proto->ctl_table,
235                                             l4proto->ctl_table_users);
236                 if (err < 0)
237                         goto out;
238         }
239 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
240         if (l4proto->ctl_compat_table != NULL) {
241                 err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
242                                             nf_net_ipv4_netfilter_sysctl_path,
243                                             l4proto->ctl_compat_table, NULL);
244                 if (err == 0)
245                         goto out;
246                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
247                                         l4proto->ctl_table,
248                                         l4proto->ctl_table_users);
249         }
250 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
251 out:
252 #endif /* CONFIG_SYSCTL */
253         return err;
254 }
255
256 static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
257 {
258 #ifdef CONFIG_SYSCTL
259         if (l4proto->ctl_table_header != NULL &&
260             *l4proto->ctl_table_header != NULL)
261                 nf_ct_unregister_sysctl(l4proto->ctl_table_header,
262                                         l4proto->ctl_table,
263                                         l4proto->ctl_table_users);
264 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
265         if (l4proto->ctl_compat_table_header != NULL)
266                 nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
267                                         l4proto->ctl_compat_table, NULL);
268 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
269 #endif /* CONFIG_SYSCTL */
270 }
271
272 /* FIXME: Allow NULL functions and sub in pointers to generic for
273    them. --RR */
274 int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
275 {
276         int ret = 0;
277
278         if (l4proto->l3proto >= PF_MAX)
279                 return -EBUSY;
280
281         mutex_lock(&nf_ct_proto_mutex);
282         if (!nf_ct_protos[l4proto->l3proto]) {
283                 /* l3proto may be loaded latter. */
284                 struct nf_conntrack_l4proto **proto_array;
285                 int i;
286
287                 proto_array = kmalloc(MAX_NF_CT_PROTO *
288                                       sizeof(struct nf_conntrack_l4proto *),
289                                       GFP_KERNEL);
290                 if (proto_array == NULL) {
291                         ret = -ENOMEM;
292                         goto out_unlock;
293                 }
294
295                 for (i = 0; i < MAX_NF_CT_PROTO; i++)
296                         proto_array[i] = &nf_conntrack_l4proto_generic;
297                 nf_ct_protos[l4proto->l3proto] = proto_array;
298         } else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] !=
299                                         &nf_conntrack_l4proto_generic) {
300                 ret = -EBUSY;
301                 goto out_unlock;
302         }
303
304         ret = nf_ct_l4proto_register_sysctl(l4proto);
305         if (ret < 0)
306                 goto out_unlock;
307
308         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
309                            l4proto);
310
311 out_unlock:
312         mutex_unlock(&nf_ct_proto_mutex);
313         return ret;
314 }
315 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
316
317 void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
318 {
319         BUG_ON(l4proto->l3proto >= PF_MAX);
320
321         mutex_lock(&nf_ct_proto_mutex);
322         BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
323         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
324                            &nf_conntrack_l4proto_generic);
325         nf_ct_l4proto_unregister_sysctl(l4proto);
326         mutex_unlock(&nf_ct_proto_mutex);
327
328         synchronize_rcu();
329
330         /* Remove all contrack entries for this protocol */
331         nf_ct_iterate_cleanup(kill_l4proto, l4proto);
332 }
333 EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);
334
335 int nf_conntrack_proto_init(void)
336 {
337         unsigned int i;
338         int err;
339
340         err = nf_ct_l4proto_register_sysctl(&nf_conntrack_l4proto_generic);
341         if (err < 0)
342                 return err;
343
344         for (i = 0; i < AF_MAX; i++)
345                 rcu_assign_pointer(nf_ct_l3protos[i],
346                                    &nf_conntrack_l3proto_generic);
347         return 0;
348 }
349
350 void nf_conntrack_proto_fini(void)
351 {
352         unsigned int i;
353
354         nf_ct_l4proto_unregister_sysctl(&nf_conntrack_l4proto_generic);
355
356         /* free l3proto protocol tables */
357         for (i = 0; i < PF_MAX; i++)
358                 kfree(nf_ct_protos[i]);
359 }