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/*
* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
*
* 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.
*
* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
* NAT funded by Astaro.
*/
#include <linux/if.h>
#include <linux/inetdevice.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/types.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter/x_tables.h>
#include <net/addrconf.h>
#include <net/checksum.h>
#include <net/protocol.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/ipv4/nf_nat_redirect.h>
unsigned int
nf_nat_redirect_ipv4(struct sk_buff *skb,
const struct nf_nat_ipv4_multi_range_compat *mr,
unsigned int hooknum)
{
struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
__be32 newdst;
struct nf_nat_range newrange;
NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING ||
hooknum == NF_INET_LOCAL_OUT);
ct = nf_ct_get(skb, &ctinfo);
NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
/* Local packets: make them go to loopback */
if (hooknum == NF_INET_LOCAL_OUT) {
newdst = htonl(0x7F000001);
} else {
struct in_device *indev;
struct in_ifaddr *ifa;
newdst = 0;
rcu_read_lock();
indev = __in_dev_get_rcu(skb->dev);
if (indev != NULL) {
ifa = indev->ifa_list;
newdst = ifa->ifa_local;
}
rcu_read_unlock();
if (!newdst)
return NF_DROP;
}
/* Transfer from original range. */
memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
newrange.min_addr.ip = newdst;
newrange.max_addr.ip = newdst;
newrange.min_proto = mr->range[0].min;
newrange.max_proto = mr->range[0].max;
/* Hand modified range to generic setup. */
return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
}
EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv4);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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