// SPDX-License-Identifier: GPL-2.0-only
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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* (C) 2011 Patrick McHardy <kaber@trash.net>
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*/
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#include <linux/module.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/ip.h>
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#include <net/ip.h>
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#include <net/netfilter/nf_nat.h>
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static int __net_init iptable_nat_table_init(struct net *net);
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static const struct xt_table nf_nat_ipv4_table = {
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.name = "nat",
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.valid_hooks = (1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_POST_ROUTING) |
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(1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_LOCAL_IN),
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.me = THIS_MODULE,
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.af = NFPROTO_IPV4,
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.table_init = iptable_nat_table_init,
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};
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static unsigned int iptable_nat_do_chain(void *priv,
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struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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return ipt_do_table(skb, state, state->net->ipv4.nat_table);
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}
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static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
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{
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.hook = iptable_nat_do_chain,
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.pf = NFPROTO_IPV4,
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.hooknum = NF_INET_PRE_ROUTING,
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.priority = NF_IP_PRI_NAT_DST,
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},
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{
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.hook = iptable_nat_do_chain,
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.pf = NFPROTO_IPV4,
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.hooknum = NF_INET_POST_ROUTING,
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.priority = NF_IP_PRI_NAT_SRC,
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},
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{
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.hook = iptable_nat_do_chain,
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.pf = NFPROTO_IPV4,
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.hooknum = NF_INET_LOCAL_OUT,
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.priority = NF_IP_PRI_NAT_DST,
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},
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{
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.hook = iptable_nat_do_chain,
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.pf = NFPROTO_IPV4,
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.hooknum = NF_INET_LOCAL_IN,
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.priority = NF_IP_PRI_NAT_SRC,
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},
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};
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static int ipt_nat_register_lookups(struct net *net)
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{
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int i, ret;
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for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
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ret = nf_nat_ipv4_register_fn(net, &nf_nat_ipv4_ops[i]);
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if (ret) {
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while (i)
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nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[--i]);
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return ret;
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}
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}
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return 0;
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}
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static void ipt_nat_unregister_lookups(struct net *net)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
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nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[i]);
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}
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static int __net_init iptable_nat_table_init(struct net *net)
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{
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struct ipt_replace *repl;
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int ret;
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if (net->ipv4.nat_table)
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return 0;
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repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
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if (repl == NULL)
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return -ENOMEM;
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ret = ipt_register_table(net, &nf_nat_ipv4_table, repl,
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NULL, &net->ipv4.nat_table);
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if (ret < 0) {
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kfree(repl);
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return ret;
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}
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ret = ipt_nat_register_lookups(net);
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if (ret < 0) {
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ipt_unregister_table(net, net->ipv4.nat_table, NULL);
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net->ipv4.nat_table = NULL;
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}
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kfree(repl);
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return ret;
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}
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static void __net_exit iptable_nat_net_pre_exit(struct net *net)
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{
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if (net->ipv4.nat_table)
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ipt_nat_unregister_lookups(net);
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}
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static void __net_exit iptable_nat_net_exit(struct net *net)
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{
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if (!net->ipv4.nat_table)
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return;
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ipt_unregister_table_exit(net, net->ipv4.nat_table);
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net->ipv4.nat_table = NULL;
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}
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static struct pernet_operations iptable_nat_net_ops = {
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.pre_exit = iptable_nat_net_pre_exit,
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.exit = iptable_nat_net_exit,
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};
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static int __init iptable_nat_init(void)
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{
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int ret = register_pernet_subsys(&iptable_nat_net_ops);
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if (ret)
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return ret;
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ret = iptable_nat_table_init(&init_net);
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if (ret)
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unregister_pernet_subsys(&iptable_nat_net_ops);
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return ret;
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}
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static void __exit iptable_nat_exit(void)
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{
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unregister_pernet_subsys(&iptable_nat_net_ops);
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}
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module_init(iptable_nat_init);
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module_exit(iptable_nat_exit);
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MODULE_LICENSE("GPL");
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