blob: 138a24bc76ad9d215e1e9b836405774adaac02e7 [file] [log] [blame]
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (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.
*/
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_l3proto.h>
static int __net_init iptable_nat_table_init(struct net *net);
static const struct xt_table nf_nat_ipv4_table = {
.name = "nat",
.valid_hooks = (1 << NF_INET_PRE_ROUTING) |
(1 << NF_INET_POST_ROUTING) |
(1 << NF_INET_LOCAL_OUT) |
(1 << NF_INET_LOCAL_IN),
.me = THIS_MODULE,
.af = NFPROTO_IPV4,
.table_init = iptable_nat_table_init,
};
static unsigned int iptable_nat_do_chain(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state,
struct nf_conn *ct)
{
return ipt_do_table(skb, state, state->net->ipv4.nat_table);
}
static unsigned int iptable_nat_ipv4_fn(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
return nf_nat_ipv4_fn(priv, skb, state, iptable_nat_do_chain);
}
static unsigned int iptable_nat_ipv4_in(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
return nf_nat_ipv4_in(priv, skb, state, iptable_nat_do_chain);
}
static unsigned int iptable_nat_ipv4_out(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
return nf_nat_ipv4_out(priv, skb, state, iptable_nat_do_chain);
}
static unsigned int iptable_nat_ipv4_local_fn(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
return nf_nat_ipv4_local_fn(priv, skb, state, iptable_nat_do_chain);
}
static struct nf_hook_ops nf_nat_ipv4_ops[] __read_mostly = {
/* Before packet filtering, change destination */
{
.hook = iptable_nat_ipv4_in,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_PRE_ROUTING,
.priority = NF_IP_PRI_NAT_DST,
},
/* After packet filtering, change source */
{
.hook = iptable_nat_ipv4_out,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_POST_ROUTING,
.priority = NF_IP_PRI_NAT_SRC,
},
/* Before packet filtering, change destination */
{
.hook = iptable_nat_ipv4_local_fn,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_OUT,
.priority = NF_IP_PRI_NAT_DST,
},
/* After packet filtering, change source */
{
.hook = iptable_nat_ipv4_fn,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_IN,
.priority = NF_IP_PRI_NAT_SRC,
},
};
static int __net_init iptable_nat_table_init(struct net *net)
{
struct ipt_replace *repl;
int ret;
if (net->ipv4.nat_table)
return 0;
repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
if (repl == NULL)
return -ENOMEM;
ret = ipt_register_table(net, &nf_nat_ipv4_table, repl,
nf_nat_ipv4_ops, &net->ipv4.nat_table);
kfree(repl);
return ret;
}
static void __net_exit iptable_nat_net_exit(struct net *net)
{
if (!net->ipv4.nat_table)
return;
ipt_unregister_table(net, net->ipv4.nat_table, nf_nat_ipv4_ops);
net->ipv4.nat_table = NULL;
}
static struct pernet_operations iptable_nat_net_ops = {
.exit = iptable_nat_net_exit,
};
static int __init iptable_nat_init(void)
{
int ret = register_pernet_subsys(&iptable_nat_net_ops);
if (ret)
return ret;
ret = iptable_nat_table_init(&init_net);
if (ret)
unregister_pernet_subsys(&iptable_nat_net_ops);
return ret;
}
static void __exit iptable_nat_exit(void)
{
unregister_pernet_subsys(&iptable_nat_net_ops);
}
module_init(iptable_nat_init);
module_exit(iptable_nat_exit);
MODULE_LICENSE("GPL");