164 lines
4.2 KiB
C
164 lines
4.2 KiB
C
/* (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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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#include <net/netfilter/nf_nat_core.h>
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#include <net/netfilter/nf_nat_l3proto.h>
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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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};
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static unsigned int iptable_nat_do_chain(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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struct nf_conn *ct)
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{
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struct net *net = nf_ct_net(ct);
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return ipt_do_table(skb, ops->hooknum, in, out, net->ipv4.nat_table);
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}
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static unsigned int iptable_nat_ipv4_fn(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return nf_nat_ipv4_fn(ops, skb, in, out, iptable_nat_do_chain);
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}
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static unsigned int iptable_nat_ipv4_in(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return nf_nat_ipv4_in(ops, skb, in, out, iptable_nat_do_chain);
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}
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static unsigned int iptable_nat_ipv4_out(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return nf_nat_ipv4_out(ops, skb, in, out, iptable_nat_do_chain);
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}
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static unsigned int iptable_nat_ipv4_local_fn(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return nf_nat_ipv4_local_fn(ops, skb, in, out, iptable_nat_do_chain);
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}
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static struct nf_hook_ops nf_nat_ipv4_ops[] __read_mostly = {
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/* Before packet filtering, change destination */
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{
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.hook = iptable_nat_ipv4_in,
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.owner = THIS_MODULE,
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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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/* After packet filtering, change source */
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{
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.hook = iptable_nat_ipv4_out,
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.owner = THIS_MODULE,
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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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/* Before packet filtering, change destination */
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{
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.hook = iptable_nat_ipv4_local_fn,
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.owner = THIS_MODULE,
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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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/* After packet filtering, change source */
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{
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.hook = iptable_nat_ipv4_fn,
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.owner = THIS_MODULE,
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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 __net_init iptable_nat_net_init(struct net *net)
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{
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struct ipt_replace *repl;
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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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net->ipv4.nat_table = ipt_register_table(net, &nf_nat_ipv4_table, repl);
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kfree(repl);
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return PTR_ERR_OR_ZERO(net->ipv4.nat_table);
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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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ipt_unregister_table(net, net->ipv4.nat_table);
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}
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static struct pernet_operations iptable_nat_net_ops = {
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.init = iptable_nat_net_init,
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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 err;
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err = register_pernet_subsys(&iptable_nat_net_ops);
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if (err < 0)
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goto err1;
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err = nf_register_hooks(nf_nat_ipv4_ops, ARRAY_SIZE(nf_nat_ipv4_ops));
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if (err < 0)
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goto err2;
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return 0;
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err2:
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unregister_pernet_subsys(&iptable_nat_net_ops);
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err1:
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return err;
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}
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static void __exit iptable_nat_exit(void)
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{
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nf_unregister_hooks(nf_nat_ipv4_ops, ARRAY_SIZE(nf_nat_ipv4_ops));
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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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