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)) | |
1da177e4 | 26 | |
35aad0ff | 27 | static const struct xt_table packet_filter = { |
1da177e4 LT |
28 | .name = "filter", |
29 | .valid_hooks = FILTER_VALID_HOOKS, | |
2e4e6a17 | 30 | .me = THIS_MODULE, |
f88e6a8a | 31 | .af = NFPROTO_IPV4, |
2b95efe7 | 32 | .priority = NF_IP_PRI_FILTER, |
1da177e4 LT |
33 | }; |
34 | ||
666953df | 35 | static unsigned int |
795aa6ef | 36 | iptable_filter_hook(const struct nf_hook_ops *ops, struct sk_buff *skb, |
238e54c9 | 37 | const struct nf_hook_state *state) |
666953df | 38 | { |
2b21e051 | 39 | const struct net *net; |
666953df | 40 | |
795aa6ef | 41 | if (ops->hooknum == 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 | |
238e54c9 DM |
47 | net = dev_net(state->in ? state->in : state->out); |
48 | return ipt_do_table(skb, ops->hooknum, state->in, state->out, | |
795aa6ef | 49 | net->ipv4.iptable_filter); |
1da177e4 LT |
50 | } |
51 | ||
2b95efe7 | 52 | static struct nf_hook_ops *filter_ops __read_mostly; |
1da177e4 LT |
53 | |
54 | /* Default to forward because I got too much mail already. */ | |
523f610e | 55 | static bool forward = true; |
1da177e4 LT |
56 | module_param(forward, bool, 0000); |
57 | ||
9335f047 AD |
58 | static int __net_init iptable_filter_net_init(struct net *net) |
59 | { | |
e3eaa991 JE |
60 | struct ipt_replace *repl; |
61 | ||
62 | repl = ipt_alloc_initial_table(&packet_filter); | |
63 | if (repl == NULL) | |
64 | return -ENOMEM; | |
65 | /* Entry 1 is the FORWARD hook */ | |
66 | ((struct ipt_standard *)repl->entries)[1].target.verdict = | |
523f610e | 67 | forward ? -NF_ACCEPT - 1 : -NF_DROP - 1; |
e3eaa991 | 68 | |
9335f047 | 69 | net->ipv4.iptable_filter = |
e3eaa991 JE |
70 | ipt_register_table(net, &packet_filter, repl); |
71 | kfree(repl); | |
8c6ffba0 | 72 | return PTR_ERR_OR_ZERO(net->ipv4.iptable_filter); |
9335f047 AD |
73 | } |
74 | ||
75 | static void __net_exit iptable_filter_net_exit(struct net *net) | |
76 | { | |
f54e9367 | 77 | ipt_unregister_table(net, net->ipv4.iptable_filter); |
9335f047 AD |
78 | } |
79 | ||
80 | static struct pernet_operations iptable_filter_net_ops = { | |
81 | .init = iptable_filter_net_init, | |
82 | .exit = iptable_filter_net_exit, | |
83 | }; | |
84 | ||
65b4b4e8 | 85 | static int __init iptable_filter_init(void) |
1da177e4 LT |
86 | { |
87 | int ret; | |
88 | ||
9335f047 AD |
89 | ret = register_pernet_subsys(&iptable_filter_net_ops); |
90 | if (ret < 0) | |
91 | return ret; | |
1da177e4 LT |
92 | |
93 | /* Register hooks */ | |
2b95efe7 JE |
94 | filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook); |
95 | if (IS_ERR(filter_ops)) { | |
96 | ret = PTR_ERR(filter_ops); | |
90efbed1 | 97 | unregister_pernet_subsys(&iptable_filter_net_ops); |
2b95efe7 | 98 | } |
1da177e4 | 99 | |
1da177e4 | 100 | return ret; |
1da177e4 LT |
101 | } |
102 | ||
65b4b4e8 | 103 | static void __exit iptable_filter_fini(void) |
1da177e4 | 104 | { |
2b95efe7 | 105 | xt_hook_unlink(&packet_filter, filter_ops); |
9335f047 | 106 | unregister_pernet_subsys(&iptable_filter_net_ops); |
1da177e4 LT |
107 | } |
108 | ||
65b4b4e8 AM |
109 | module_init(iptable_filter_init); |
110 | module_exit(iptable_filter_fini); |