2 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
4 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
5 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/netfilter_ipv4/ip_tables.h>
16 #include <linux/slab.h>
19 MODULE_LICENSE("GPL");
20 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
21 MODULE_DESCRIPTION("iptables filter table");
23 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
24 (1 << NF_INET_FORWARD) | \
25 (1 << NF_INET_LOCAL_OUT))
27 static const struct xt_table packet_filter = {
29 .valid_hooks = FILTER_VALID_HOOKS,
32 .priority = NF_IP_PRI_FILTER,
36 iptable_filter_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
37 const struct nf_hook_state *state)
39 if (ops->hooknum == NF_INET_LOCAL_OUT &&
40 (skb->len < sizeof(struct iphdr) ||
41 ip_hdrlen(skb) < sizeof(struct iphdr)))
42 /* root is playing with raw sockets. */
45 return ipt_do_table(skb, ops->hooknum, state,
46 state->net->ipv4.iptable_filter);
49 static struct nf_hook_ops *filter_ops __read_mostly;
51 /* Default to forward because I got too much mail already. */
52 static bool forward = true;
53 module_param(forward, bool, 0000);
55 static int __net_init iptable_filter_net_init(struct net *net)
57 struct ipt_replace *repl;
59 repl = ipt_alloc_initial_table(&packet_filter);
62 /* Entry 1 is the FORWARD hook */
63 ((struct ipt_standard *)repl->entries)[1].target.verdict =
64 forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
66 net->ipv4.iptable_filter =
67 ipt_register_table(net, &packet_filter, repl);
69 return PTR_ERR_OR_ZERO(net->ipv4.iptable_filter);
72 static void __net_exit iptable_filter_net_exit(struct net *net)
74 ipt_unregister_table(net, net->ipv4.iptable_filter);
77 static struct pernet_operations iptable_filter_net_ops = {
78 .init = iptable_filter_net_init,
79 .exit = iptable_filter_net_exit,
82 static int __init iptable_filter_init(void)
86 ret = register_pernet_subsys(&iptable_filter_net_ops);
91 filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook);
92 if (IS_ERR(filter_ops)) {
93 ret = PTR_ERR(filter_ops);
94 unregister_pernet_subsys(&iptable_filter_net_ops);
100 static void __exit iptable_filter_fini(void)
102 xt_hook_unlink(&packet_filter, filter_ops);
103 unregister_pernet_subsys(&iptable_filter_net_ops);
106 module_init(iptable_filter_init);
107 module_exit(iptable_filter_fini);