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/* Kernel module to match connection tracking information. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_compat.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_state.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
MODULE_DESCRIPTION("iptables connection tracking state match module");
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
int *hotdrop)
{
const struct ipt_state_info *sinfo = matchinfo;
enum ip_conntrack_info ctinfo;
unsigned int statebit;
if (nf_ct_is_untracked(skb))
statebit = IPT_STATE_UNTRACKED;
else if (!nf_ct_get_ctinfo(skb, &ctinfo))
statebit = IPT_STATE_INVALID;
else
statebit = IPT_STATE_BIT(ctinfo);
return (sinfo->statemask & statebit);
}
static int check(const char *tablename,
const struct ipt_ip *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
if (matchsize != IPT_ALIGN(sizeof(struct ipt_state_info)))
return 0;
return 1;
}
static struct ipt_match state_match = {
.name = "state",
.match = &match,
.checkentry = &check,
.me = THIS_MODULE,
};
static int __init init(void)
{
need_ip_conntrack();
return ipt_register_match(&state_match);
}
static void __exit fini(void)
{
ipt_unregister_match(&state_match);
}
module_init(init);
module_exit(fini);
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