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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> | |
fe0b9294 | 27 | #include <net/netfilter/nf_conntrack_compat.h> |
1da177e4 LT |
28 | |
29 | MODULE_LICENSE("GPL"); | |
30 | MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>"); | |
31 | MODULE_DESCRIPTION("iptables helper match module"); | |
2e4e6a17 HW |
32 | MODULE_ALIAS("ipt_helper"); |
33 | MODULE_ALIAS("ip6t_helper"); | |
1da177e4 LT |
34 | |
35 | #if 0 | |
36 | #define DEBUGP printk | |
37 | #else | |
38 | #define DEBUGP(format, args...) | |
39 | #endif | |
40 | ||
9fb9cbb1 | 41 | #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) |
1da177e4 LT |
42 | static int |
43 | match(const struct sk_buff *skb, | |
44 | const struct net_device *in, | |
45 | const struct net_device *out, | |
c4986734 | 46 | const struct xt_match *match, |
1da177e4 LT |
47 | const void *matchinfo, |
48 | int offset, | |
2e4e6a17 | 49 | unsigned int protoff, |
1da177e4 LT |
50 | int *hotdrop) |
51 | { | |
2e4e6a17 | 52 | const struct xt_helper_info *info = matchinfo; |
1da177e4 LT |
53 | struct ip_conntrack *ct; |
54 | enum ip_conntrack_info ctinfo; | |
55 | int ret = info->invert; | |
601e68e1 | 56 | |
1da177e4 LT |
57 | ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo); |
58 | if (!ct) { | |
2e4e6a17 | 59 | DEBUGP("xt_helper: Eek! invalid conntrack?\n"); |
1da177e4 LT |
60 | return ret; |
61 | } | |
62 | ||
63 | if (!ct->master) { | |
2e4e6a17 | 64 | DEBUGP("xt_helper: conntrack %p has no master\n", ct); |
1da177e4 LT |
65 | return ret; |
66 | } | |
67 | ||
e45b1be8 | 68 | read_lock_bh(&ip_conntrack_lock); |
1da177e4 | 69 | if (!ct->master->helper) { |
601e68e1 | 70 | DEBUGP("xt_helper: master ct %p has no helper\n", |
1da177e4 LT |
71 | exp->expectant); |
72 | goto out_unlock; | |
73 | } | |
74 | ||
601e68e1 | 75 | DEBUGP("master's name = %s , info->name = %s\n", |
1da177e4 LT |
76 | ct->master->helper->name, info->name); |
77 | ||
78 | if (info->name[0] == '\0') | |
79 | ret ^= 1; | |
80 | else | |
601e68e1 YH |
81 | ret ^= !strncmp(ct->master->helper->name, info->name, |
82 | strlen(ct->master->helper->name)); | |
1da177e4 | 83 | out_unlock: |
e45b1be8 | 84 | read_unlock_bh(&ip_conntrack_lock); |
1da177e4 LT |
85 | return ret; |
86 | } | |
87 | ||
9fb9cbb1 YK |
88 | #else /* CONFIG_IP_NF_CONNTRACK */ |
89 | ||
90 | static int | |
91 | match(const struct sk_buff *skb, | |
92 | const struct net_device *in, | |
93 | const struct net_device *out, | |
c4986734 | 94 | const struct xt_match *match, |
9fb9cbb1 YK |
95 | const void *matchinfo, |
96 | int offset, | |
2e4e6a17 | 97 | unsigned int protoff, |
9fb9cbb1 YK |
98 | int *hotdrop) |
99 | { | |
2e4e6a17 | 100 | const struct xt_helper_info *info = matchinfo; |
9fb9cbb1 | 101 | struct nf_conn *ct; |
dc808fe2 | 102 | struct nf_conn_help *master_help; |
9fb9cbb1 YK |
103 | enum ip_conntrack_info ctinfo; |
104 | int ret = info->invert; | |
601e68e1 | 105 | |
9fb9cbb1 YK |
106 | ct = nf_ct_get((struct sk_buff *)skb, &ctinfo); |
107 | if (!ct) { | |
2e4e6a17 | 108 | DEBUGP("xt_helper: Eek! invalid conntrack?\n"); |
9fb9cbb1 YK |
109 | return ret; |
110 | } | |
111 | ||
112 | if (!ct->master) { | |
2e4e6a17 | 113 | DEBUGP("xt_helper: conntrack %p has no master\n", ct); |
9fb9cbb1 YK |
114 | return ret; |
115 | } | |
116 | ||
117 | read_lock_bh(&nf_conntrack_lock); | |
dc808fe2 HW |
118 | master_help = nfct_help(ct->master); |
119 | if (!master_help || !master_help->helper) { | |
601e68e1 | 120 | DEBUGP("xt_helper: master ct %p has no helper\n", |
9fb9cbb1 YK |
121 | exp->expectant); |
122 | goto out_unlock; | |
123 | } | |
124 | ||
601e68e1 | 125 | DEBUGP("master's name = %s , info->name = %s\n", |
9fb9cbb1 YK |
126 | ct->master->helper->name, info->name); |
127 | ||
128 | if (info->name[0] == '\0') | |
129 | ret ^= 1; | |
130 | else | |
dc808fe2 | 131 | ret ^= !strncmp(master_help->helper->name, info->name, |
601e68e1 | 132 | strlen(master_help->helper->name)); |
9fb9cbb1 YK |
133 | out_unlock: |
134 | read_unlock_bh(&nf_conntrack_lock); | |
135 | return ret; | |
136 | } | |
137 | #endif | |
138 | ||
1da177e4 | 139 | static int check(const char *tablename, |
2e4e6a17 | 140 | const void *inf, |
c4986734 | 141 | const struct xt_match *match, |
1da177e4 | 142 | void *matchinfo, |
1da177e4 LT |
143 | unsigned int hook_mask) |
144 | { | |
2e4e6a17 | 145 | struct xt_helper_info *info = matchinfo; |
1da177e4 | 146 | |
b9f78f9f | 147 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { |
fe0b9294 | 148 | printk(KERN_WARNING "can't load conntrack support for " |
b9f78f9f PNA |
149 | "proto=%d\n", match->family); |
150 | return 0; | |
151 | } | |
1da177e4 | 152 | info->name[29] = '\0'; |
1da177e4 LT |
153 | return 1; |
154 | } | |
155 | ||
b9f78f9f | 156 | static void |
efa74165 | 157 | destroy(const struct xt_match *match, void *matchinfo) |
b9f78f9f | 158 | { |
b9f78f9f | 159 | nf_ct_l3proto_module_put(match->family); |
b9f78f9f PNA |
160 | } |
161 | ||
4470bbc7 PM |
162 | static struct xt_match xt_helper_match[] = { |
163 | { | |
164 | .name = "helper", | |
165 | .family = AF_INET, | |
166 | .checkentry = check, | |
167 | .match = match, | |
168 | .destroy = destroy, | |
169 | .matchsize = sizeof(struct xt_helper_info), | |
170 | .me = THIS_MODULE, | |
171 | }, | |
172 | { | |
173 | .name = "helper", | |
174 | .family = AF_INET6, | |
175 | .checkentry = check, | |
176 | .match = match, | |
177 | .destroy = destroy, | |
178 | .matchsize = sizeof(struct xt_helper_info), | |
179 | .me = THIS_MODULE, | |
180 | }, | |
1da177e4 LT |
181 | }; |
182 | ||
65b4b4e8 | 183 | static int __init xt_helper_init(void) |
1da177e4 | 184 | { |
4470bbc7 PM |
185 | return xt_register_matches(xt_helper_match, |
186 | ARRAY_SIZE(xt_helper_match)); | |
1da177e4 LT |
187 | } |
188 | ||
65b4b4e8 | 189 | static void __exit xt_helper_fini(void) |
1da177e4 | 190 | { |
4470bbc7 | 191 | xt_unregister_matches(xt_helper_match, ARRAY_SIZE(xt_helper_match)); |
1da177e4 LT |
192 | } |
193 | ||
65b4b4e8 AM |
194 | module_init(xt_helper_init); |
195 | module_exit(xt_helper_fini); | |
1da177e4 | 196 |