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/* Kernel module to match connection tracking information. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2005 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.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_state.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
MODULE_ALIAS("ipt_state");
MODULE_ALIAS("ip6t_state");
static bool
state_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
const struct xt_state_info *sinfo = par->matchinfo;
enum ip_conntrack_info ctinfo;
unsigned int statebit;
if (nf_ct_is_untracked(skb))
statebit = XT_STATE_UNTRACKED;
else if (!nf_ct_get(skb, &ctinfo))
statebit = XT_STATE_INVALID;
else
statebit = XT_STATE_BIT(ctinfo);
return (sinfo->statemask & statebit);
}
static int state_mt_check(const struct xt_mtchk_param *par)
{
int ret;
ret = nf_ct_l3proto_try_module_get(par->family);
if (ret < 0) {
pr_info("cannot load conntrack support for proto=%u\n",
par->family);
return ret;
}
return 0;
}
static void state_mt_destroy(const struct xt_mtdtor_param *par)
{
nf_ct_l3proto_module_put(par->family);
}
static struct xt_match state_mt_reg[] __read_mostly = {
{
.name = "state",
.family = NFPROTO_IPV4,
.checkentry = state_mt_check,
.match = state_mt,
.destroy = state_mt_destroy,
.matchsize = sizeof(struct xt_state_info),
.me = THIS_MODULE,
},
{
.name = "state",
.family = NFPROTO_IPV6,
.checkentry = state_mt_check,
.match = state_mt,
.destroy = state_mt_destroy,
.matchsize = sizeof(struct xt_state_info),
.me = THIS_MODULE,
},
};
static int __init state_mt_init(void)
{
return xt_register_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
}
static void __exit state_mt_exit(void)
{
xt_unregister_matches(state_mt_reg, ARRAY_SIZE(state_mt_reg));
}
module_init(state_mt_init);
module_exit(state_mt_exit);
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