Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x. | |
3 | * | |
4 | * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling | |
5 | * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> | |
6 | * | |
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. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/netfilter_ipv4/ip_tables.h> | |
5a0e3ad6 | 16 | #include <linux/slab.h> |
c9bdd4b5 | 17 | #include <net/ip.h> |
1da177e4 LT |
18 | |
19 | MODULE_LICENSE("GPL"); | |
20 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
21 | MODULE_DESCRIPTION("iptables filter table"); | |
22 | ||
6e23ae2a PM |
23 | #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \ |
24 | (1 << NF_INET_FORWARD) | \ | |
25 | (1 << NF_INET_LOCAL_OUT)) | |
b9e69e12 | 26 | static int __net_init iptable_filter_table_init(struct net *net); |
1da177e4 | 27 | |
35aad0ff | 28 | static const struct xt_table packet_filter = { |
1da177e4 LT |
29 | .name = "filter", |
30 | .valid_hooks = FILTER_VALID_HOOKS, | |
2e4e6a17 | 31 | .me = THIS_MODULE, |
f88e6a8a | 32 | .af = NFPROTO_IPV4, |
2b95efe7 | 33 | .priority = NF_IP_PRI_FILTER, |
b9e69e12 | 34 | .table_init = iptable_filter_table_init, |
1da177e4 LT |
35 | }; |
36 | ||
666953df | 37 | static unsigned int |
06198b34 | 38 | iptable_filter_hook(void *priv, struct sk_buff *skb, |
238e54c9 | 39 | const struct nf_hook_state *state) |
666953df | 40 | { |
6cb8ff3f | 41 | if (state->hook == NF_INET_LOCAL_OUT && |
2b21e051 JE |
42 | (skb->len < sizeof(struct iphdr) || |
43 | ip_hdrlen(skb) < sizeof(struct iphdr))) | |
44 | /* root is playing with raw sockets. */ | |
45 | return NF_ACCEPT; | |
1da177e4 | 46 | |
6cb8ff3f | 47 | return ipt_do_table(skb, state, state->net->ipv4.iptable_filter); |
1da177e4 LT |
48 | } |
49 | ||
2b95efe7 | 50 | static struct nf_hook_ops *filter_ops __read_mostly; |
1da177e4 LT |
51 | |
52 | /* Default to forward because I got too much mail already. */ | |
b9e69e12 | 53 | static bool forward __read_mostly = true; |
1da177e4 LT |
54 | module_param(forward, bool, 0000); |
55 | ||
b9e69e12 | 56 | static int __net_init iptable_filter_table_init(struct net *net) |
9335f047 | 57 | { |
e3eaa991 | 58 | struct ipt_replace *repl; |
a67dd266 | 59 | int err; |
e3eaa991 | 60 | |
b9e69e12 FW |
61 | if (net->ipv4.iptable_filter) |
62 | return 0; | |
63 | ||
e3eaa991 JE |
64 | repl = ipt_alloc_initial_table(&packet_filter); |
65 | if (repl == NULL) | |
66 | return -ENOMEM; | |
67 | /* Entry 1 is the FORWARD hook */ | |
68 | ((struct ipt_standard *)repl->entries)[1].target.verdict = | |
523f610e | 69 | forward ? -NF_ACCEPT - 1 : -NF_DROP - 1; |
e3eaa991 | 70 | |
a67dd266 FW |
71 | err = ipt_register_table(net, &packet_filter, repl, filter_ops, |
72 | &net->ipv4.iptable_filter); | |
e3eaa991 | 73 | kfree(repl); |
a67dd266 | 74 | return err; |
9335f047 AD |
75 | } |
76 | ||
b9e69e12 FW |
77 | static int __net_init iptable_filter_net_init(struct net *net) |
78 | { | |
79 | if (net == &init_net || !forward) | |
80 | return iptable_filter_table_init(net); | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
9335f047 AD |
85 | static void __net_exit iptable_filter_net_exit(struct net *net) |
86 | { | |
b9e69e12 FW |
87 | if (!net->ipv4.iptable_filter) |
88 | return; | |
a67dd266 | 89 | ipt_unregister_table(net, net->ipv4.iptable_filter, filter_ops); |
b9e69e12 | 90 | net->ipv4.iptable_filter = NULL; |
9335f047 AD |
91 | } |
92 | ||
93 | static struct pernet_operations iptable_filter_net_ops = { | |
94 | .init = iptable_filter_net_init, | |
95 | .exit = iptable_filter_net_exit, | |
96 | }; | |
97 | ||
65b4b4e8 | 98 | static int __init iptable_filter_init(void) |
1da177e4 LT |
99 | { |
100 | int ret; | |
101 | ||
b9e69e12 FW |
102 | filter_ops = xt_hook_ops_alloc(&packet_filter, iptable_filter_hook); |
103 | if (IS_ERR(filter_ops)) | |
104 | return PTR_ERR(filter_ops); | |
105 | ||
9335f047 AD |
106 | ret = register_pernet_subsys(&iptable_filter_net_ops); |
107 | if (ret < 0) | |
b9e69e12 | 108 | kfree(filter_ops); |
1da177e4 | 109 | |
1da177e4 | 110 | return ret; |
1da177e4 LT |
111 | } |
112 | ||
65b4b4e8 | 113 | static void __exit iptable_filter_fini(void) |
1da177e4 | 114 | { |
9335f047 | 115 | unregister_pernet_subsys(&iptable_filter_net_ops); |
b9e69e12 | 116 | kfree(filter_ops); |
1da177e4 LT |
117 | } |
118 | ||
65b4b4e8 AM |
119 | module_init(iptable_filter_init); |
120 | module_exit(iptable_filter_fini); |