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
|
/* Kernel module to match connection tracking information. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.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/module.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_compat.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_state.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
MODULE_ALIAS("ipt_state");
MODULE_ALIAS("ip6t_state");
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
const struct xt_state_info *sinfo = matchinfo;
enum ip_conntrack_info ctinfo;
unsigned int statebit;
if (nf_ct_is_untracked(skb))
statebit = XT_STATE_UNTRACKED;
else if (!nf_ct_get_ctinfo(skb, &ctinfo))
statebit = XT_STATE_INVALID;
else
statebit = XT_STATE_BIT(ctinfo);
return (sinfo->statemask & statebit);
}
static int check(const char *tablename,
const void *inf,
const struct xt_match *match,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
if (nf_ct_l3proto_try_module_get(match->family) < 0) {
printk(KERN_WARNING "can't load nf_conntrack support for "
"proto=%d\n", match->family);
return 0;
}
#endif
return 1;
}
static void
destroy(const struct xt_match *match, void *matchinfo, unsigned int matchsize)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
nf_ct_l3proto_module_put(match->family);
#endif
}
static struct xt_match state_match = {
.name = "state",
.match = match,
.checkentry = check,
.destroy = destroy,
.matchsize = sizeof(struct xt_state_info),
.family = AF_INET,
.me = THIS_MODULE,
};
static struct xt_match state6_match = {
.name = "state",
.match = match,
.checkentry = check,
.destroy = destroy,
.matchsize = sizeof(struct xt_state_info),
.family = AF_INET6,
.me = THIS_MODULE,
};
static int __init xt_state_init(void)
{
int ret;
need_conntrack();
ret = xt_register_match(&state_match);
if (ret < 0)
return ret;
ret = xt_register_match(&state6_match);
if (ret < 0)
xt_unregister_match(&state_match);
return ret;
}
static void __exit xt_state_fini(void)
{
xt_unregister_match(&state_match);
xt_unregister_match(&state6_match);
}
module_init(xt_state_init);
module_exit(xt_state_fini);
|
