1 /* iptables module to match on related connections */
3 * (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se>
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.
9 * 19 Mar 2002 Harald Welte <laforge@gnumonks.org>:
10 * - Port to newnat infrastructure
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/netfilter.h>
16 #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
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>
21 #include <net/netfilter/nf_conntrack.h>
22 #include <net/netfilter/nf_conntrack_core.h>
23 #include <net/netfilter/nf_conntrack_helper.h>
25 #include <linux/netfilter/x_tables.h>
26 #include <linux/netfilter/xt_helper.h>
28 MODULE_LICENSE("GPL");
29 MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>");
30 MODULE_DESCRIPTION("iptables helper match module");
31 MODULE_ALIAS("ipt_helper");
32 MODULE_ALIAS("ip6t_helper");
37 #define DEBUGP(format, args...)
40 #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
42 match(const struct sk_buff *skb,
43 const struct net_device *in,
44 const struct net_device *out,
45 const struct xt_match *match,
46 const void *matchinfo,
51 const struct xt_helper_info *info = matchinfo;
52 struct ip_conntrack *ct;
53 enum ip_conntrack_info ctinfo;
54 int ret = info->invert;
56 ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
58 DEBUGP("xt_helper: Eek! invalid conntrack?\n");
63 DEBUGP("xt_helper: conntrack %p has no master\n", ct);
67 read_lock_bh(&ip_conntrack_lock);
68 if (!ct->master->helper) {
69 DEBUGP("xt_helper: master ct %p has no helper\n",
74 DEBUGP("master's name = %s , info->name = %s\n",
75 ct->master->helper->name, info->name);
77 if (info->name[0] == '\0')
80 ret ^= !strncmp(ct->master->helper->name, info->name,
81 strlen(ct->master->helper->name));
83 read_unlock_bh(&ip_conntrack_lock);
87 #else /* CONFIG_IP_NF_CONNTRACK */
90 match(const struct sk_buff *skb,
91 const struct net_device *in,
92 const struct net_device *out,
93 const struct xt_match *match,
94 const void *matchinfo,
99 const struct xt_helper_info *info = matchinfo;
101 struct nf_conn_help *master_help;
102 enum ip_conntrack_info ctinfo;
103 int ret = info->invert;
105 ct = nf_ct_get((struct sk_buff *)skb, &ctinfo);
107 DEBUGP("xt_helper: Eek! invalid conntrack?\n");
112 DEBUGP("xt_helper: conntrack %p has no master\n", ct);
116 read_lock_bh(&nf_conntrack_lock);
117 master_help = nfct_help(ct->master);
118 if (!master_help || !master_help->helper) {
119 DEBUGP("xt_helper: master ct %p has no helper\n",
124 DEBUGP("master's name = %s , info->name = %s\n",
125 ct->master->helper->name, info->name);
127 if (info->name[0] == '\0')
130 ret ^= !strncmp(master_help->helper->name, info->name,
131 strlen(master_help->helper->name));
133 read_unlock_bh(&nf_conntrack_lock);
138 static int check(const char *tablename,
140 const struct xt_match *match,
142 unsigned int matchsize,
143 unsigned int hook_mask)
145 struct xt_helper_info *info = matchinfo;
147 info->name[29] = '\0';
151 static struct xt_match helper_match = {
154 .matchsize = sizeof(struct xt_helper_info),
158 static struct xt_match helper6_match = {
161 .matchsize = sizeof(struct xt_helper_info),
166 static int __init init(void)
171 ret = xt_register_match(AF_INET, &helper_match);
175 ret = xt_register_match(AF_INET6, &helper6_match);
177 xt_unregister_match(AF_INET, &helper_match);
182 static void __exit fini(void)
184 xt_unregister_match(AF_INET, &helper_match);
185 xt_unregister_match(AF_INET6, &helper6_match);