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 | 141 | void *matchinfo, |
1da177e4 LT |
142 | unsigned int hook_mask) |
143 | { | |
2e4e6a17 | 144 | struct xt_helper_info *info = matchinfo; |
1da177e4 | 145 | |
b9f78f9f PNA |
146 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
147 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { | |
148 | printk(KERN_WARNING "can't load nf_conntrack support for " | |
149 | "proto=%d\n", match->family); | |
150 | return 0; | |
151 | } | |
152 | #endif | |
1da177e4 | 153 | info->name[29] = '\0'; |
1da177e4 LT |
154 | return 1; |
155 | } | |
156 | ||
b9f78f9f | 157 | static void |
efa74165 | 158 | destroy(const struct xt_match *match, void *matchinfo) |
b9f78f9f PNA |
159 | { |
160 | #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) | |
161 | nf_ct_l3proto_module_put(match->family); | |
162 | #endif | |
163 | } | |
164 | ||
4470bbc7 PM |
165 | static struct xt_match xt_helper_match[] = { |
166 | { | |
167 | .name = "helper", | |
168 | .family = AF_INET, | |
169 | .checkentry = check, | |
170 | .match = match, | |
171 | .destroy = destroy, | |
172 | .matchsize = sizeof(struct xt_helper_info), | |
173 | .me = THIS_MODULE, | |
174 | }, | |
175 | { | |
176 | .name = "helper", | |
177 | .family = AF_INET6, | |
178 | .checkentry = check, | |
179 | .match = match, | |
180 | .destroy = destroy, | |
181 | .matchsize = sizeof(struct xt_helper_info), | |
182 | .me = THIS_MODULE, | |
183 | }, | |
1da177e4 LT |
184 | }; |
185 | ||
65b4b4e8 | 186 | static int __init xt_helper_init(void) |
1da177e4 | 187 | { |
2e4e6a17 | 188 | need_conntrack(); |
4470bbc7 PM |
189 | return xt_register_matches(xt_helper_match, |
190 | ARRAY_SIZE(xt_helper_match)); | |
1da177e4 LT |
191 | } |
192 | ||
65b4b4e8 | 193 | static void __exit xt_helper_fini(void) |
1da177e4 | 194 | { |
4470bbc7 | 195 | xt_unregister_matches(xt_helper_match, ARRAY_SIZE(xt_helper_match)); |
1da177e4 LT |
196 | } |
197 | ||
65b4b4e8 AM |
198 | module_init(xt_helper_init); |
199 | module_exit(xt_helper_fini); | |
1da177e4 | 200 |