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// SPDX-License-Identifier: GPL-2.0-only
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2011 Patrick McHardy <kaber@trash.net>
*/
#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>
struct iptable_nat_pernet {
struct nf_hook_ops *nf_nat_ops;
};
static unsigned int iptable_nat_net_id __read_mostly;
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,
};
static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
{
.hook = ipt_do_table,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_PRE_ROUTING,
.priority = NF_IP_PRI_NAT_DST,
},
{
.hook = ipt_do_table,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_POST_ROUTING,
.priority = NF_IP_PRI_NAT_SRC,
},
{
.hook = ipt_do_table,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_OUT,
.priority = NF_IP_PRI_NAT_DST,
},
{
.hook = ipt_do_table,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_IN,
.priority = NF_IP_PRI_NAT_SRC,
},
};
static int ipt_nat_register_lookups(struct net *net)
{
struct iptable_nat_pernet *xt_nat_net;
struct nf_hook_ops *ops;
struct xt_table *table;
int i, ret;
xt_nat_net = net_generic(net, iptable_nat_net_id);
table = xt_find_table(net, NFPROTO_IPV4, "nat");
if (WARN_ON_ONCE(!table))
return -ENOENT;
ops = kmemdup(nf_nat_ipv4_ops, sizeof(nf_nat_ipv4_ops), GFP_KERNEL);
if (!ops)
return -ENOMEM;
for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
ops[i].priv = table;
ret = nf_nat_ipv4_register_fn(net, &ops[i]);
if (ret) {
while (i)
nf_nat_ipv4_unregister_fn(net, &ops[--i]);
kfree(ops);
return ret;
}
}
xt_nat_net->nf_nat_ops = ops;
return 0;
}
static void ipt_nat_unregister_lookups(struct net *net)
{
struct iptable_nat_pernet *xt_nat_net = net_generic(net, iptable_nat_net_id);
struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops;
int i;
if (!ops)
return;
for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
nf_nat_ipv4_unregister_fn(net, &ops[i]);
kfree(ops);
}
static int iptable_nat_table_init(struct net *net)
{
struct ipt_replace *repl;
int ret;
repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
if (repl == NULL)
return -ENOMEM;
ret = ipt_register_table(net, &nf_nat_ipv4_table, repl, NULL);
if (ret < 0) {
kfree(repl);
return ret;
}
ret = ipt_nat_register_lookups(net);
if (ret < 0)
ipt_unregister_table_exit(net, "nat");
kfree(repl);
return ret;
}
static void __net_exit iptable_nat_net_pre_exit(struct net *net)
{
ipt_nat_unregister_lookups(net);
}
static void __net_exit iptable_nat_net_exit(struct net *net)
{
ipt_unregister_table_exit(net, "nat");
}
static struct pernet_operations iptable_nat_net_ops = {
.pre_exit = iptable_nat_net_pre_exit,
.exit = iptable_nat_net_exit,
.id = &iptable_nat_net_id,
.size = sizeof(struct iptable_nat_pernet),
};
static int __init iptable_nat_init(void)
{
int ret = xt_register_template(&nf_nat_ipv4_table,
iptable_nat_table_init);
if (ret < 0)
return ret;
ret = register_pernet_subsys(&iptable_nat_net_ops);
if (ret < 0) {
xt_unregister_template(&nf_nat_ipv4_table);
return ret;
}
return ret;
}
static void __exit iptable_nat_exit(void)
{
unregister_pernet_subsys(&iptable_nat_net_ops);
xt_unregister_template(&nf_nat_ipv4_table);
}
module_init(iptable_nat_init);
module_exit(iptable_nat_exit);
MODULE_LICENSE("GPL");
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