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(void *priv
, struct sk_buff
*skb
,
37 const struct nf_hook_state
*state
)
39 if (state
->hook
== 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
, state
, state
->net
->ipv4
.iptable_filter
);
48 static struct nf_hook_ops
*filter_ops __read_mostly
;
50 /* Default to forward because I got too much mail already. */
51 static bool forward
= true;
52 module_param(forward
, bool, 0000);
54 static int __net_init
iptable_filter_net_init(struct net
*net
)
56 struct ipt_replace
*repl
;
58 repl
= ipt_alloc_initial_table(&packet_filter
);
61 /* Entry 1 is the FORWARD hook */
62 ((struct ipt_standard
*)repl
->entries
)[1].target
.verdict
=
63 forward
? -NF_ACCEPT
- 1 : -NF_DROP
- 1;
65 net
->ipv4
.iptable_filter
=
66 ipt_register_table(net
, &packet_filter
, repl
);
68 return PTR_ERR_OR_ZERO(net
->ipv4
.iptable_filter
);
71 static void __net_exit
iptable_filter_net_exit(struct net
*net
)
73 ipt_unregister_table(net
, net
->ipv4
.iptable_filter
);
76 static struct pernet_operations iptable_filter_net_ops
= {
77 .init
= iptable_filter_net_init
,
78 .exit
= iptable_filter_net_exit
,
81 static int __init
iptable_filter_init(void)
85 ret
= register_pernet_subsys(&iptable_filter_net_ops
);
90 filter_ops
= xt_hook_link(&packet_filter
, iptable_filter_hook
);
91 if (IS_ERR(filter_ops
)) {
92 ret
= PTR_ERR(filter_ops
);
93 unregister_pernet_subsys(&iptable_filter_net_ops
);
99 static void __exit
iptable_filter_fini(void)
101 xt_hook_unlink(&packet_filter
, filter_ops
);
102 unregister_pernet_subsys(&iptable_filter_net_ops
);
105 module_init(iptable_filter_init
);
106 module_exit(iptable_filter_fini
);