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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>
- 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)
- {
- return ipt_do_table(skb, state, state->net->ipv4.nat_table);
- }
- static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
- {
- .hook = iptable_nat_do_chain,
- .pf = NFPROTO_IPV4,
- .hooknum = NF_INET_PRE_ROUTING,
- .priority = NF_IP_PRI_NAT_DST,
- },
- {
- .hook = iptable_nat_do_chain,
- .pf = NFPROTO_IPV4,
- .hooknum = NF_INET_POST_ROUTING,
- .priority = NF_IP_PRI_NAT_SRC,
- },
- {
- .hook = iptable_nat_do_chain,
- .pf = NFPROTO_IPV4,
- .hooknum = NF_INET_LOCAL_OUT,
- .priority = NF_IP_PRI_NAT_DST,
- },
- {
- .hook = iptable_nat_do_chain,
- .pf = NFPROTO_IPV4,
- .hooknum = NF_INET_LOCAL_IN,
- .priority = NF_IP_PRI_NAT_SRC,
- },
- };
- static int ipt_nat_register_lookups(struct net *net)
- {
- int i, ret;
- for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
- ret = nf_nat_ipv4_register_fn(net, &nf_nat_ipv4_ops[i]);
- if (ret) {
- while (i)
- nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[--i]);
- return ret;
- }
- }
- return 0;
- }
- static void ipt_nat_unregister_lookups(struct net *net)
- {
- int i;
- for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
- nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[i]);
- }
- 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,
- NULL, &net->ipv4.nat_table);
- if (ret < 0) {
- kfree(repl);
- return ret;
- }
- ret = ipt_nat_register_lookups(net);
- if (ret < 0) {
- ipt_unregister_table(net, net->ipv4.nat_table, NULL);
- net->ipv4.nat_table = NULL;
- }
- kfree(repl);
- return ret;
- }
- static void __net_exit iptable_nat_net_pre_exit(struct net *net)
- {
- if (net->ipv4.nat_table)
- ipt_nat_unregister_lookups(net);
- }
- static void __net_exit iptable_nat_net_exit(struct net *net)
- {
- if (!net->ipv4.nat_table)
- return;
- ipt_unregister_table_exit(net, net->ipv4.nat_table);
- net->ipv4.nat_table = NULL;
- }
- static struct pernet_operations iptable_nat_net_ops = {
- .pre_exit = iptable_nat_net_pre_exit,
- .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");
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