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))
26 static int __net_init
iptable_filter_table_init(struct net
*net
);
28 static const struct xt_table packet_filter
= {
30 .valid_hooks
= FILTER_VALID_HOOKS
,
33 .priority
= NF_IP_PRI_FILTER
,
34 .table_init
= iptable_filter_table_init
,
38 iptable_filter_hook(void *priv
, struct sk_buff
*skb
,
39 const struct nf_hook_state
*state
)
41 if (state
->hook
== NF_INET_LOCAL_OUT
&&
42 (skb
->len
< sizeof(struct iphdr
) ||
43 ip_hdrlen(skb
) < sizeof(struct iphdr
)))
44 /* root is playing with raw sockets. */
47 return ipt_do_table(skb
, state
, state
->net
->ipv4
.iptable_filter
);
50 static struct nf_hook_ops
*filter_ops __read_mostly
;
52 /* Default to forward because I got too much mail already. */
53 static bool forward __read_mostly
= true;
54 module_param(forward
, bool, 0000);
56 static int __net_init
iptable_filter_table_init(struct net
*net
)
58 struct ipt_replace
*repl
;
61 if (net
->ipv4
.iptable_filter
)
64 repl
= ipt_alloc_initial_table(&packet_filter
);
67 /* Entry 1 is the FORWARD hook */
68 ((struct ipt_standard
*)repl
->entries
)[1].target
.verdict
=
69 forward
? -NF_ACCEPT
- 1 : -NF_DROP
- 1;
71 err
= ipt_register_table(net
, &packet_filter
, repl
, filter_ops
,
72 &net
->ipv4
.iptable_filter
);
77 static int __net_init
iptable_filter_net_init(struct net
*net
)
79 if (net
== &init_net
|| !forward
)
80 return iptable_filter_table_init(net
);
85 static void __net_exit
iptable_filter_net_exit(struct net
*net
)
87 if (!net
->ipv4
.iptable_filter
)
89 ipt_unregister_table(net
, net
->ipv4
.iptable_filter
, filter_ops
);
90 net
->ipv4
.iptable_filter
= NULL
;
93 static struct pernet_operations iptable_filter_net_ops
= {
94 .init
= iptable_filter_net_init
,
95 .exit
= iptable_filter_net_exit
,
98 static int __init
iptable_filter_init(void)
102 filter_ops
= xt_hook_ops_alloc(&packet_filter
, iptable_filter_hook
);
103 if (IS_ERR(filter_ops
))
104 return PTR_ERR(filter_ops
);
106 ret
= register_pernet_subsys(&iptable_filter_net_ops
);
113 static void __exit
iptable_filter_fini(void)
115 unregister_pernet_subsys(&iptable_filter_net_ops
);
119 module_init(iptable_filter_init
);
120 module_exit(iptable_filter_fini
);