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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> | |
c9bdd4b5 | 16 | #include <net/ip.h> |
1da177e4 LT |
17 | |
18 | MODULE_LICENSE("GPL"); | |
19 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
20 | MODULE_DESCRIPTION("iptables filter table"); | |
21 | ||
6e23ae2a PM |
22 | #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \ |
23 | (1 << NF_INET_FORWARD) | \ | |
24 | (1 << NF_INET_LOCAL_OUT)) | |
1da177e4 | 25 | |
35aad0ff | 26 | static const struct xt_table packet_filter = { |
1da177e4 LT |
27 | .name = "filter", |
28 | .valid_hooks = FILTER_VALID_HOOKS, | |
2e4e6a17 | 29 | .me = THIS_MODULE, |
f88e6a8a | 30 | .af = NFPROTO_IPV4, |
2b95efe7 | 31 | .priority = NF_IP_PRI_FILTER, |
1da177e4 LT |
32 | }; |
33 | ||
666953df | 34 | static unsigned int |
737535c5 JE |
35 | iptable_filter_hook(unsigned int hook, struct sk_buff *skb, |
36 | const struct net_device *in, const struct net_device *out, | |
37 | int (*okfn)(struct sk_buff *)) | |
666953df | 38 | { |
2b21e051 | 39 | const struct net *net; |
666953df | 40 | |
2b21e051 JE |
41 | if (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. */ | |
45 | return NF_ACCEPT; | |
1da177e4 | 46 | |
2b21e051 JE |
47 | net = dev_net((in != NULL) ? in : out); |
48 | return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_filter); | |
1da177e4 LT |
49 | } |
50 | ||
2b95efe7 | 51 | static struct nf_hook_ops *filter_ops __read_mostly; |
1da177e4 LT |
52 | |
53 | /* Default to forward because I got too much mail already. */ | |
54 | static int forward = NF_ACCEPT; | |
55 | module_param(forward, bool, 0000); | |
56 | ||
9335f047 AD |
57 | static int __net_init iptable_filter_net_init(struct net *net) |
58 | { | |
e3eaa991 JE |
59 | struct ipt_replace *repl; |
60 | ||
61 | repl = ipt_alloc_initial_table(&packet_filter); | |
62 | if (repl == NULL) | |
63 | return -ENOMEM; | |
64 | /* Entry 1 is the FORWARD hook */ | |
65 | ((struct ipt_standard *)repl->entries)[1].target.verdict = | |
66 | -forward - 1; | |
67 | ||
9335f047 | 68 | net->ipv4.iptable_filter = |
e3eaa991 JE |
69 | ipt_register_table(net, &packet_filter, repl); |
70 | kfree(repl); | |
9335f047 AD |
71 | if (IS_ERR(net->ipv4.iptable_filter)) |
72 | return PTR_ERR(net->ipv4.iptable_filter); | |
73 | return 0; | |
74 | } | |
75 | ||
76 | static void __net_exit iptable_filter_net_exit(struct net *net) | |
77 | { | |
f54e9367 | 78 | ipt_unregister_table(net, net->ipv4.iptable_filter); |
9335f047 AD |
79 | } |
80 | ||
81 | static struct pernet_operations iptable_filter_net_ops = { | |
82 | .init = iptable_filter_net_init, | |
83 | .exit = iptable_filter_net_exit, | |
84 | }; | |
85 | ||
65b4b4e8 | 86 | static int __init iptable_filter_init(void) |
1da177e4 LT |
87 | { |
88 | int ret; | |
89 | ||
90 | if (forward < 0 || forward > NF_MAX_VERDICT) { | |
91 | printk("iptables forward must be 0 or 1\n"); | |
92 | return -EINVAL; | |
93 | } | |
94 | ||
9335f047 AD |
95 | ret = register_pernet_subsys(&iptable_filter_net_ops); |
96 | if (ret < 0) | |
97 | return ret; | |
1da177e4 LT |
98 | |
99 | /* Register hooks */ | |
2b95efe7 JE |
100 | filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook); |
101 | if (IS_ERR(filter_ops)) { | |
102 | ret = PTR_ERR(filter_ops); | |
1da177e4 | 103 | goto cleanup_table; |
2b95efe7 | 104 | } |
1da177e4 | 105 | |
1da177e4 LT |
106 | return ret; |
107 | ||
1da177e4 | 108 | cleanup_table: |
9335f047 | 109 | unregister_pernet_subsys(&iptable_filter_net_ops); |
1da177e4 LT |
110 | return ret; |
111 | } | |
112 | ||
65b4b4e8 | 113 | static void __exit iptable_filter_fini(void) |
1da177e4 | 114 | { |
2b95efe7 | 115 | xt_hook_unlink(&packet_filter, filter_ops); |
9335f047 | 116 | unregister_pernet_subsys(&iptable_filter_net_ops); |
1da177e4 LT |
117 | } |
118 | ||
65b4b4e8 AM |
119 | module_init(iptable_filter_init); |
120 | module_exit(iptable_filter_fini); |