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
|
/* iptables module to match on related connections */
/*
* (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se>
*
* 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.
*
* 19 Mar 2002 Harald Welte <laforge@gnumonks.org>:
* - Port to newnat infrastructure
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
#include <linux/netfilter_ipv4/ip_conntrack.h>
#include <linux/netfilter_ipv4/ip_conntrack_core.h>
#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
#else
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_helper.h>
#endif
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_helper.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>");
MODULE_DESCRIPTION("iptables helper match module");
MODULE_ALIAS("ipt_helper");
MODULE_ALIAS("ip6t_helper");
#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif
#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
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_helper_info *info = matchinfo;
struct ip_conntrack *ct;
enum ip_conntrack_info ctinfo;
int ret = info->invert;
ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
if (!ct) {
DEBUGP("xt_helper: Eek! invalid conntrack?\n");
return ret;
}
if (!ct->master) {
DEBUGP("xt_helper: conntrack %p has no master\n", ct);
return ret;
}
read_lock_bh(&ip_conntrack_lock);
if (!ct->master->helper) {
DEBUGP("xt_helper: master ct %p has no helper\n",
exp->expectant);
goto out_unlock;
}
DEBUGP("master's name = %s , info->name = %s\n",
ct->master->helper->name, info->name);
if (info->name[0] == '\0')
ret ^= 1;
else
ret ^= !strncmp(ct->master->helper->name, info->name,
strlen(ct->master->helper->name));
out_unlock:
read_unlock_bh(&ip_conntrack_lock);
return ret;
}
#else /* CONFIG_IP_NF_CONNTRACK */
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_helper_info *info = matchinfo;
struct nf_conn *ct;
struct nf_conn_help *master_help;
enum ip_conntrack_info ctinfo;
int ret = info->invert;
ct = nf_ct_get((struct sk_buff *)skb, &ctinfo);
if (!ct) {
DEBUGP("xt_helper: Eek! invalid conntrack?\n");
return ret;
}
if (!ct->master) {
DEBUGP("xt_helper: conntrack %p has no master\n", ct);
return ret;
}
read_lock_bh(&nf_conntrack_lock);
master_help = nfct_help(ct->master);
if (!master_help || !master_help->helper) {
DEBUGP("xt_helper: master ct %p has no helper\n",
exp->expectant);
goto out_unlock;
}
DEBUGP("master's name = %s , info->name = %s\n",
ct->master->helper->name, info->name);
if (info->name[0] == '\0')
ret ^= 1;
else
ret ^= !strncmp(master_help->helper->name, info->name,
strlen(master_help->helper->name));
out_unlock:
read_unlock_bh(&nf_conntrack_lock);
return ret;
}
#endif
static int check(const char *tablename,
const void *inf,
const struct xt_match *match,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
struct xt_helper_info *info = matchinfo;
#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
info->name[29] = '\0';
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 helper_match = {
.name = "helper",
.match = match,
.matchsize = sizeof(struct xt_helper_info),
.checkentry = check,
.destroy = destroy,
.family = AF_INET,
.me = THIS_MODULE,
};
static struct xt_match helper6_match = {
.name = "helper",
.match = match,
.matchsize = sizeof(struct xt_helper_info),
.checkentry = check,
.destroy = destroy,
.family = AF_INET6,
.me = THIS_MODULE,
};
static int __init xt_helper_init(void)
{
int ret;
need_conntrack();
ret = xt_register_match(&helper_match);
if (ret < 0)
return ret;
ret = xt_register_match(&helper6_match);
if (ret < 0)
xt_unregister_match(&helper_match);
return ret;
}
static void __exit xt_helper_fini(void)
{
xt_unregister_match(&helper_match);
xt_unregister_match(&helper6_match);
}
module_init(xt_helper_init);
module_exit(xt_helper_fini);
|
