1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
|
/* L3/L4 protocol support for nf_conntrack. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/stddef.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_core.h>
static struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly;
struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly;
EXPORT_SYMBOL_GPL(nf_ct_l3protos);
static DEFINE_MUTEX(nf_ct_proto_mutex);
#ifdef CONFIG_SYSCTL
static int
nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_path *path,
struct ctl_table *table, unsigned int *users)
{
if (*header == NULL) {
*header = register_sysctl_paths(path, table);
if (*header == NULL)
return -ENOMEM;
}
if (users != NULL)
(*users)++;
return 0;
}
static void
nf_ct_unregister_sysctl(struct ctl_table_header **header,
struct ctl_table *table, unsigned int *users)
{
if (users != NULL && --*users > 0)
return;
unregister_sysctl_table(*header);
*header = NULL;
}
#endif
struct nf_conntrack_l4proto *
__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
{
if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
return &nf_conntrack_l4proto_generic;
return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
}
EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
/* this is guaranteed to always return a valid protocol helper, since
* it falls back to generic_protocol */
struct nf_conntrack_l4proto *
nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
{
struct nf_conntrack_l4proto *p;
rcu_read_lock();
p = __nf_ct_l4proto_find(l3proto, l4proto);
if (!try_module_get(p->me))
p = &nf_conntrack_l4proto_generic;
rcu_read_unlock();
return p;
}
EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
{
module_put(p->me);
}
EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
struct nf_conntrack_l3proto *
nf_ct_l3proto_find_get(u_int16_t l3proto)
{
struct nf_conntrack_l3proto *p;
rcu_read_lock();
p = __nf_ct_l3proto_find(l3proto);
if (!try_module_get(p->me))
p = &nf_conntrack_l3proto_generic;
rcu_read_unlock();
return p;
}
EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
{
module_put(p->me);
}
EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
int
nf_ct_l3proto_try_module_get(unsigned short l3proto)
{
int ret;
struct nf_conntrack_l3proto *p;
retry: p = nf_ct_l3proto_find_get(l3proto);
if (p == &nf_conntrack_l3proto_generic) {
ret = request_module("nf_conntrack-%d", l3proto);
if (!ret)
goto retry;
return -EPROTOTYPE;
}
return 0;
}
EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
void nf_ct_l3proto_module_put(unsigned short l3proto)
{
struct nf_conntrack_l3proto *p;
/* rcu_read_lock not necessary since the caller holds a reference */
p = __nf_ct_l3proto_find(l3proto);
module_put(p->me);
}
EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
static int kill_l3proto(struct nf_conn *i, void *data)
{
return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
}
static int kill_l4proto(struct nf_conn *i, void *data)
{
struct nf_conntrack_l4proto *l4proto;
l4proto = (struct nf_conntrack_l4proto *)data;
return nf_ct_protonum(i) == l4proto->l4proto &&
nf_ct_l3num(i) == l4proto->l3proto;
}
static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
{
int err = 0;
#ifdef CONFIG_SYSCTL
if (l3proto->ctl_table != NULL) {
err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
l3proto->ctl_table_path,
l3proto->ctl_table, NULL);
}
#endif
return err;
}
static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
{
#ifdef CONFIG_SYSCTL
if (l3proto->ctl_table_header != NULL)
nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
l3proto->ctl_table, NULL);
#endif
}
int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
{
int ret = 0;
if (proto->l3proto >= AF_MAX)
return -EBUSY;
mutex_lock(&nf_ct_proto_mutex);
if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
ret = -EBUSY;
goto out_unlock;
}
ret = nf_ct_l3proto_register_sysctl(proto);
if (ret < 0)
goto out_unlock;
rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
out_unlock:
mutex_unlock(&nf_ct_proto_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
{
struct net *net;
BUG_ON(proto->l3proto >= AF_MAX);
mutex_lock(&nf_ct_proto_mutex);
BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
&nf_conntrack_l3proto_generic);
nf_ct_l3proto_unregister_sysctl(proto);
mutex_unlock(&nf_ct_proto_mutex);
synchronize_rcu();
/* Remove all contrack entries for this protocol */
rtnl_lock();
for_each_net(net)
nf_ct_iterate_cleanup(net, kill_l3proto, proto);
rtnl_unlock();
}
EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
{
int err = 0;
#ifdef CONFIG_SYSCTL
if (l4proto->ctl_table != NULL) {
err = nf_ct_register_sysctl(l4proto->ctl_table_header,
nf_net_netfilter_sysctl_path,
l4proto->ctl_table,
l4proto->ctl_table_users);
if (err < 0)
goto out;
}
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
if (l4proto->ctl_compat_table != NULL) {
err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
nf_net_ipv4_netfilter_sysctl_path,
l4proto->ctl_compat_table, NULL);
if (err == 0)
goto out;
nf_ct_unregister_sysctl(l4proto->ctl_table_header,
l4proto->ctl_table,
l4proto->ctl_table_users);
}
#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
out:
#endif /* CONFIG_SYSCTL */
return err;
}
static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
{
#ifdef CONFIG_SYSCTL
if (l4proto->ctl_table_header != NULL &&
*l4proto->ctl_table_header != NULL)
nf_ct_unregister_sysctl(l4proto->ctl_table_header,
l4proto->ctl_table,
l4proto->ctl_table_users);
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
if (l4proto->ctl_compat_table_header != NULL)
nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
l4proto->ctl_compat_table, NULL);
#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
#endif /* CONFIG_SYSCTL */
}
/* FIXME: Allow NULL functions and sub in pointers to generic for
them. --RR */
int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
{
int ret = 0;
if (l4proto->l3proto >= PF_MAX)
return -EBUSY;
mutex_lock(&nf_ct_proto_mutex);
if (!nf_ct_protos[l4proto->l3proto]) {
/* l3proto may be loaded latter. */
struct nf_conntrack_l4proto **proto_array;
int i;
proto_array = kmalloc(MAX_NF_CT_PROTO *
sizeof(struct nf_conntrack_l4proto *),
GFP_KERNEL);
if (proto_array == NULL) {
ret = -ENOMEM;
goto out_unlock;
}
for (i = 0; i < MAX_NF_CT_PROTO; i++)
proto_array[i] = &nf_conntrack_l4proto_generic;
nf_ct_protos[l4proto->l3proto] = proto_array;
} else if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto] !=
&
|