Commit | Line | Data |
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1da177e4 LT |
1 | /* iptables module to match on related connections */ |
2 | /* | |
3 | * (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * 19 Mar 2002 Harald Welte <laforge@gnumonks.org>: | |
10 | * - Port to newnat infrastructure | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/netfilter.h> | |
9fb9cbb1 | 16 | #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) |
1da177e4 LT |
17 | #include <linux/netfilter_ipv4/ip_conntrack.h> |
18 | #include <linux/netfilter_ipv4/ip_conntrack_core.h> | |
19 | #include <linux/netfilter_ipv4/ip_conntrack_helper.h> | |
9fb9cbb1 YK |
20 | #else |
21 | #include <net/netfilter/nf_conntrack.h> | |
22 | #include <net/netfilter/nf_conntrack_core.h> | |
23 | #include <net/netfilter/nf_conntrack_helper.h> | |
24 | #endif | |
2e4e6a17 HW |
25 | #include <linux/netfilter/x_tables.h> |
26 | #include <linux/netfilter/xt_helper.h> | |
1da177e4 LT |
27 | |
28 | MODULE_LICENSE("GPL"); | |
29 | MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>"); | |
30 | MODULE_DESCRIPTION("iptables helper match module"); | |
2e4e6a17 HW |
31 | MODULE_ALIAS("ipt_helper"); |
32 | MODULE_ALIAS("ip6t_helper"); | |
1da177e4 LT |
33 | |
34 | #if 0 | |
35 | #define DEBUGP printk | |
36 | #else | |
37 | #define DEBUGP(format, args...) | |
38 | #endif | |
39 | ||
9fb9cbb1 | 40 | #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) |
1da177e4 LT |
41 | static int |
42 | match(const struct sk_buff *skb, | |
43 | const struct net_device *in, | |
44 | const struct net_device *out, | |
c4986734 | 45 | const struct xt_match *match, |
1da177e4 LT |
46 | const void *matchinfo, |
47 | int offset, | |
2e4e6a17 | 48 | unsigned int protoff, |
1da177e4 LT |
49 | int *hotdrop) |
50 | { | |
2e4e6a17 | 51 | const struct xt_helper_info *info = matchinfo; |
1da177e4 LT |
52 | struct ip_conntrack *ct; |
53 | enum ip_conntrack_info ctinfo; | |
54 | int ret = info->invert; | |
55 | ||
56 | ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo); | |
57 | if (!ct) { | |
2e4e6a17 | 58 | DEBUGP("xt_helper: Eek! invalid conntrack?\n"); |
1da177e4 LT |
59 | return ret; |
60 | } | |
61 | ||
62 | if (!ct->master) { | |
2e4e6a17 | 63 | DEBUGP("xt_helper: conntrack %p has no master\n", ct); |
1da177e4 LT |
64 | return ret; |
65 | } | |
66 | ||
e45b1be8 | 67 | read_lock_bh(&ip_conntrack_lock); |
1da177e4 | 68 | if (!ct->master->helper) { |
2e4e6a17 | 69 | DEBUGP("xt_helper: master ct %p has no helper\n", |
1da177e4 LT |
70 | exp->expectant); |
71 | goto out_unlock; | |
72 | } | |
73 | ||
74 | DEBUGP("master's name = %s , info->name = %s\n", | |
75 | ct->master->helper->name, info->name); | |
76 | ||
77 | if (info->name[0] == '\0') | |
78 | ret ^= 1; | |
79 | else | |
80 | ret ^= !strncmp(ct->master->helper->name, info->name, | |
81 | strlen(ct->master->helper->name)); | |
82 | out_unlock: | |
e45b1be8 | 83 | read_unlock_bh(&ip_conntrack_lock); |
1da177e4 LT |
84 | return ret; |
85 | } | |
86 | ||
9fb9cbb1 YK |
87 | #else /* CONFIG_IP_NF_CONNTRACK */ |
88 | ||
89 | static int | |
90 | match(const struct sk_buff *skb, | |
91 | const struct net_device *in, | |
92 | const struct net_device *out, | |
c4986734 | 93 | const struct xt_match *match, |
9fb9cbb1 YK |
94 | const void *matchinfo, |
95 | int offset, | |
2e4e6a17 | 96 | unsigned int protoff, |
9fb9cbb1 YK |
97 | int *hotdrop) |
98 | { | |
2e4e6a17 | 99 | const struct xt_helper_info *info = matchinfo; |
9fb9cbb1 | 100 | struct nf_conn *ct; |
dc808fe2 | 101 | struct nf_conn_help *master_help; |
9fb9cbb1 YK |
102 | enum ip_conntrack_info ctinfo; |
103 | int ret = info->invert; | |
104 | ||
105 | ct = nf_ct_get((struct sk_buff *)skb, &ctinfo); | |
106 | if (!ct) { | |
2e4e6a17 | 107 | DEBUGP("xt_helper: Eek! invalid conntrack?\n"); |
9fb9cbb1 YK |
108 | return ret; |
109 | } | |
110 | ||
111 | if (!ct->master) { | |
2e4e6a17 | 112 | DEBUGP("xt_helper: conntrack %p has no master\n", ct); |
9fb9cbb1 YK |
113 | return ret; |
114 | } | |
115 | ||
116 | read_lock_bh(&nf_conntrack_lock); | |
dc808fe2 HW |
117 | master_help = nfct_help(ct->master); |
118 | if (!master_help || !master_help->helper) { | |
2e4e6a17 | 119 | DEBUGP("xt_helper: master ct %p has no helper\n", |
9fb9cbb1 YK |
120 | exp->expectant); |
121 | goto out_unlock; | |
122 | } | |
123 | ||
124 | DEBUGP("master's name = %s , info->name = %s\n", | |
125 | ct->master->helper->name, info->name); | |
126 | ||
127 | if (info->name[0] == '\0') | |
128 | ret ^= 1; | |
129 | else | |
dc808fe2 HW |
130 | ret ^= !strncmp(master_help->helper->name, info->name, |
131 | strlen(master_help->helper->name)); | |
9fb9cbb1 YK |
132 | out_unlock: |
133 | read_unlock_bh(&nf_conntrack_lock); | |
134 | return ret; | |
135 | } | |
136 | #endif | |
137 | ||
1da177e4 | 138 | static int check(const char *tablename, |
2e4e6a17 | 139 | const void *inf, |
c4986734 | 140 | const struct xt_match *match, |
1da177e4 LT |
141 | void *matchinfo, |
142 | unsigned int matchsize, | |
143 | unsigned int hook_mask) | |
144 | { | |
2e4e6a17 | 145 | struct xt_helper_info *info = matchinfo; |
1da177e4 | 146 | |
b9f78f9f PNA |
147 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
148 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { | |
149 | printk(KERN_WARNING "can't load nf_conntrack support for " | |
150 | "proto=%d\n", match->family); | |
151 | return 0; | |
152 | } | |
153 | #endif | |
1da177e4 | 154 | info->name[29] = '\0'; |
1da177e4 LT |
155 | return 1; |
156 | } | |
157 | ||
b9f78f9f PNA |
158 | static void |
159 | destroy(const struct xt_match *match, void *matchinfo, unsigned int matchsize) | |
160 | { | |
161 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) | |
162 | nf_ct_l3proto_module_put(match->family); | |
163 | #endif | |
164 | } | |
165 | ||
2e4e6a17 HW |
166 | static struct xt_match helper_match = { |
167 | .name = "helper", | |
5d04bff0 PM |
168 | .match = match, |
169 | .matchsize = sizeof(struct xt_helper_info), | |
170 | .checkentry = check, | |
b9f78f9f | 171 | .destroy = destroy, |
a45049c5 | 172 | .family = AF_INET, |
2e4e6a17 HW |
173 | .me = THIS_MODULE, |
174 | }; | |
175 | static struct xt_match helper6_match = { | |
1da177e4 | 176 | .name = "helper", |
5d04bff0 PM |
177 | .match = match, |
178 | .matchsize = sizeof(struct xt_helper_info), | |
179 | .checkentry = check, | |
b9f78f9f | 180 | .destroy = destroy, |
a45049c5 | 181 | .family = AF_INET6, |
1da177e4 LT |
182 | .me = THIS_MODULE, |
183 | }; | |
184 | ||
65b4b4e8 | 185 | static int __init xt_helper_init(void) |
1da177e4 | 186 | { |
2e4e6a17 HW |
187 | int ret; |
188 | need_conntrack(); | |
189 | ||
a45049c5 | 190 | ret = xt_register_match(&helper_match); |
2e4e6a17 HW |
191 | if (ret < 0) |
192 | return ret; | |
193 | ||
a45049c5 | 194 | ret = xt_register_match(&helper6_match); |
2e4e6a17 | 195 | if (ret < 0) |
a45049c5 | 196 | xt_unregister_match(&helper_match); |
2e4e6a17 HW |
197 | |
198 | return ret; | |
1da177e4 LT |
199 | } |
200 | ||
65b4b4e8 | 201 | static void __exit xt_helper_fini(void) |
1da177e4 | 202 | { |
a45049c5 PNA |
203 | xt_unregister_match(&helper_match); |
204 | xt_unregister_match(&helper6_match); | |
1da177e4 LT |
205 | } |
206 | ||
65b4b4e8 AM |
207 | module_init(xt_helper_init); |
208 | module_exit(xt_helper_fini); | |
1da177e4 | 209 |