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/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
*
* 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.
*
* Version: 0.0.7
*
* Thu 21 Mar 2002 Harald Welte <laforge@gnumonks.org>
* - Port to newnat API
*
* This module currently supports DNAT:
* iptables -t nat -A PREROUTING -d x.x.x.x -j DNAT --to-dest x.x.x.y
*
* and SNAT:
* iptables -t nat -A POSTROUTING { -j MASQUERADE , -j SNAT --to-source x.x.x.x }
*
* It has not been tested with
* -j SNAT --to-source x.x.x.x-x.x.x.y since I only have one external ip
* If you do test this please let me know if it works or not.
*
*/
#include <linux/module.h>
#include <linux/netfilter_ipv4.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
#include <linux/netfilter_ipv4/ip_conntrack_tftp.h>
#include <linux/netfilter_ipv4/ip_nat_helper.h>
#include <linux/netfilter_ipv4/ip_nat_rule.h>
#include <linux/moduleparam.h>
MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
MODULE_DESCRIPTION("tftp NAT helper");
MODULE_LICENSE("GPL");
static unsigned int help(struct sk_buff **pskb,
enum ip_conntrack_info ctinfo,
struct ip_conntrack_expect *exp)
{
struct ip_conntrack *ct = exp->master;
exp->saved_proto.udp.port
= ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
exp->dir = IP_CT_DIR_REPLY;
exp->expectfn = ip_nat_follow_master;
if (ip_conntrack_expect_related(exp) != 0)
return NF_DROP;
return NF_ACCEPT;
}
static void __exit ip_nat_tftp_fini(void)
{
rcu_assign_pointer(ip_nat_tftp_hook, NULL);
synchronize_rcu();
}
static int __init ip_nat_tftp_init(void)
{
BUG_ON(rcu_dereference(ip_nat_tftp_hook));
rcu_assign_pointer(ip_nat_tftp_hook, help);
return 0;
}
module_init(ip_nat_tftp_init);
module_exit(ip_nat_tftp_fini);
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