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. | |
1da177e4 LT |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/netfilter.h> | |
9fb9cbb1 YK |
13 | #include <net/netfilter/nf_conntrack.h> |
14 | #include <net/netfilter/nf_conntrack_core.h> | |
15 | #include <net/netfilter/nf_conntrack_helper.h> | |
2e4e6a17 HW |
16 | #include <linux/netfilter/x_tables.h> |
17 | #include <linux/netfilter/xt_helper.h> | |
1da177e4 LT |
18 | |
19 | MODULE_LICENSE("GPL"); | |
20 | MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>"); | |
21 | MODULE_DESCRIPTION("iptables helper match module"); | |
2e4e6a17 HW |
22 | MODULE_ALIAS("ipt_helper"); |
23 | MODULE_ALIAS("ip6t_helper"); | |
1da177e4 | 24 | |
1da177e4 | 25 | |
1d93a9cb | 26 | static bool |
9fb9cbb1 YK |
27 | match(const struct sk_buff *skb, |
28 | const struct net_device *in, | |
29 | const struct net_device *out, | |
c4986734 | 30 | const struct xt_match *match, |
9fb9cbb1 YK |
31 | const void *matchinfo, |
32 | int offset, | |
2e4e6a17 | 33 | unsigned int protoff, |
cff533ac | 34 | bool *hotdrop) |
9fb9cbb1 | 35 | { |
2e4e6a17 | 36 | const struct xt_helper_info *info = matchinfo; |
a47362a2 JE |
37 | const struct nf_conn *ct; |
38 | const struct nf_conn_help *master_help; | |
342b7e3c | 39 | const struct nf_conntrack_helper *helper; |
9fb9cbb1 | 40 | enum ip_conntrack_info ctinfo; |
1d93a9cb | 41 | bool ret = info->invert; |
601e68e1 | 42 | |
a47362a2 | 43 | ct = nf_ct_get(skb, &ctinfo); |
342b7e3c | 44 | if (!ct || !ct->master) |
9fb9cbb1 | 45 | return ret; |
9fb9cbb1 | 46 | |
dc808fe2 | 47 | master_help = nfct_help(ct->master); |
342b7e3c PM |
48 | if (!master_help) |
49 | return ret; | |
9fb9cbb1 | 50 | |
342b7e3c PM |
51 | /* rcu_read_lock()ed by nf_hook_slow */ |
52 | helper = rcu_dereference(master_help->helper); | |
53 | if (!helper) | |
54 | return ret; | |
9fb9cbb1 YK |
55 | |
56 | if (info->name[0] == '\0') | |
1d93a9cb | 57 | ret = !ret; |
9fb9cbb1 | 58 | else |
dc808fe2 | 59 | ret ^= !strncmp(master_help->helper->name, info->name, |
601e68e1 | 60 | strlen(master_help->helper->name)); |
9fb9cbb1 YK |
61 | return ret; |
62 | } | |
9fb9cbb1 | 63 | |
ccb79bdc JE |
64 | static bool check(const char *tablename, |
65 | const void *inf, | |
66 | const struct xt_match *match, | |
67 | void *matchinfo, | |
68 | unsigned int hook_mask) | |
1da177e4 | 69 | { |
2e4e6a17 | 70 | struct xt_helper_info *info = matchinfo; |
1da177e4 | 71 | |
b9f78f9f | 72 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { |
fe0b9294 | 73 | printk(KERN_WARNING "can't load conntrack support for " |
b9f78f9f | 74 | "proto=%d\n", match->family); |
ccb79bdc | 75 | return false; |
b9f78f9f | 76 | } |
1da177e4 | 77 | info->name[29] = '\0'; |
ccb79bdc | 78 | return true; |
1da177e4 LT |
79 | } |
80 | ||
b9f78f9f | 81 | static void |
efa74165 | 82 | destroy(const struct xt_match *match, void *matchinfo) |
b9f78f9f | 83 | { |
b9f78f9f | 84 | nf_ct_l3proto_module_put(match->family); |
b9f78f9f PNA |
85 | } |
86 | ||
9f15c530 | 87 | static struct xt_match xt_helper_match[] __read_mostly = { |
4470bbc7 PM |
88 | { |
89 | .name = "helper", | |
90 | .family = AF_INET, | |
91 | .checkentry = check, | |
92 | .match = match, | |
93 | .destroy = destroy, | |
94 | .matchsize = sizeof(struct xt_helper_info), | |
95 | .me = THIS_MODULE, | |
96 | }, | |
97 | { | |
98 | .name = "helper", | |
99 | .family = AF_INET6, | |
100 | .checkentry = check, | |
101 | .match = match, | |
102 | .destroy = destroy, | |
103 | .matchsize = sizeof(struct xt_helper_info), | |
104 | .me = THIS_MODULE, | |
105 | }, | |
1da177e4 LT |
106 | }; |
107 | ||
65b4b4e8 | 108 | static int __init xt_helper_init(void) |
1da177e4 | 109 | { |
4470bbc7 PM |
110 | return xt_register_matches(xt_helper_match, |
111 | ARRAY_SIZE(xt_helper_match)); | |
1da177e4 LT |
112 | } |
113 | ||
65b4b4e8 | 114 | static void __exit xt_helper_fini(void) |
1da177e4 | 115 | { |
4470bbc7 | 116 | xt_unregister_matches(xt_helper_match, ARRAY_SIZE(xt_helper_match)); |
1da177e4 LT |
117 | } |
118 | ||
65b4b4e8 AM |
119 | module_init(xt_helper_init); |
120 | module_exit(xt_helper_fini); | |
1da177e4 | 121 |