| /* (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 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 unsigned int iptable_nat_do_chain(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct nf_hook_state *state, |
| struct nf_conn *ct) |
| { |
| struct net *net = nf_ct_net(ct); |
| |
| return ipt_do_table(skb, ops->hooknum, state, net->ipv4.nat_table); |
| } |
| |
| static unsigned int iptable_nat_ipv4_fn(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct nf_hook_state *state) |
| { |
| return nf_nat_ipv4_fn(ops, skb, state, iptable_nat_do_chain); |
| } |
| |
| static unsigned int iptable_nat_ipv4_in(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct nf_hook_state *state) |
| { |
| return nf_nat_ipv4_in(ops, skb, state, iptable_nat_do_chain); |
| } |
| |
| static unsigned int iptable_nat_ipv4_out(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct nf_hook_state *state) |
| { |
| return nf_nat_ipv4_out(ops, skb, state, iptable_nat_do_chain); |
| } |
| |
| static unsigned int iptable_nat_ipv4_local_fn(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct nf_hook_state *state) |
| { |
| return nf_nat_ipv4_local_fn(ops, 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, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_PRE_ROUTING, |
| .priority = NF_IP_PRI_NAT_DST, |
| }, |
| /* After packet filtering, change source */ |
| { |
| .hook = iptable_nat_ipv4_out, |
| .owner = THIS_MODULE, |
| .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, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_LOCAL_OUT, |
| .priority = NF_IP_PRI_NAT_DST, |
| }, |
| /* After packet filtering, change source */ |
| { |
| .hook = iptable_nat_ipv4_fn, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_LOCAL_IN, |
| .priority = NF_IP_PRI_NAT_SRC, |
| }, |
| }; |
| |
| static int __net_init iptable_nat_net_init(struct net *net) |
| { |
| struct ipt_replace *repl; |
| |
| repl = ipt_alloc_initial_table(&nf_nat_ipv4_table); |
| if (repl == NULL) |
| return -ENOMEM; |
| net->ipv4.nat_table = ipt_register_table(net, &nf_nat_ipv4_table, repl); |
| kfree(repl); |
| return PTR_ERR_OR_ZERO(net->ipv4.nat_table); |
| } |
| |
| static void __net_exit iptable_nat_net_exit(struct net *net) |
| { |
| ipt_unregister_table(net, net->ipv4.nat_table); |
| } |
| |
| static struct pernet_operations iptable_nat_net_ops = { |
| .init = iptable_nat_net_init, |
| .exit = iptable_nat_net_exit, |
| }; |
| |
| static int __init iptable_nat_init(void) |
| { |
| int err; |
| |
| err = register_pernet_subsys(&iptable_nat_net_ops); |
| if (err < 0) |
| goto err1; |
| |
| err = nf_register_hooks(nf_nat_ipv4_ops, ARRAY_SIZE(nf_nat_ipv4_ops)); |
| if (err < 0) |
| goto err2; |
| return 0; |
| |
| err2: |
| unregister_pernet_subsys(&iptable_nat_net_ops); |
| err1: |
| return err; |
| } |
| |
| static void __exit iptable_nat_exit(void) |
| { |
| nf_unregister_hooks(nf_nat_ipv4_ops, ARRAY_SIZE(nf_nat_ipv4_ops)); |
| unregister_pernet_subsys(&iptable_nat_net_ops); |
| } |
| |
| module_init(iptable_nat_init); |
| module_exit(iptable_nat_exit); |
| |
| MODULE_LICENSE("GPL"); |