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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_compat.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 int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
const struct xt_state_info *sinfo = matchinfo;
enum ip_conntrack_info ctinfo;
unsigned int statebit;
if (nf_ct_is_untracked(skb))
statebit = XT_STATE_UNTRACKED;
else if (!nf_ct_get_ctinfo(skb, &ctinfo))
statebit = XT_STATE_INVALID;
else
statebit = XT_STATE_BIT(ctinfo);
return (sinfo->statemask & statebit);
}
static int check(const char *tablename,
const void *inf,
const struct xt_match *match,
void *matchinfo,
unsigned int hook_mask)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
if (nf_ct_l3proto_try_module_get(match->family) < 0) {
printk(KERN_WARNING "can't load nf_conntrack support for "
"proto=%d\n", match->family);
return 0;
}
#endif
return 1;
}
static void
destroy(const struct xt_match *match, void *matchinfo)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
nf_ct_l3proto_module_put(match->family);
#endif
}
static struct xt_match xt_state_match[] = {
{
.name = "state",
.family = AF_INET,
.checkentry = check,
.match = match,
.destroy = destroy,
.matchsize = sizeof(struct xt_state_info),
.me = THIS_MODULE,
},
{
.name = "state",
.family = AF_INET6,
.checkentry = check,
.match = match,
.destroy = destroy,
.matchsize = sizeof(struct xt_state_info),
.me = THIS_MODULE,
},
};
static int __init xt_state_init(void)
{
need_conntrack();
return xt_register_matches(xt_state_match, ARRAY_SIZE(xt_state_match));
}
static void __exit xt_state_fini(void)
{
xt_unregister_matches(xt_state_match, ARRAY_SIZE(xt_state_match));
}
module_init(xt_state_init);
module_exit(xt_state_fini);
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