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.
11 #include <linux/module.h>
12 #include <linux/netfilter_ipv4/ip_tables.h>
13 #include <linux/netdevice.h>
14 #include <linux/skbuff.h>
16 #include <net/route.h>
20 MODULE_LICENSE("GPL");
21 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
22 MODULE_DESCRIPTION("iptables mangle table");
24 #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
25 (1 << NF_INET_LOCAL_IN) | \
26 (1 << NF_INET_FORWARD) | \
27 (1 << NF_INET_LOCAL_OUT) | \
28 (1 << NF_INET_POST_ROUTING))
30 /* Ouch - five different hooks? Maybe this should be a config option..... -- BC */
33 struct ipt_replace repl;
34 struct ipt_standard entries[5];
35 struct ipt_error term;
36 } initial_table __net_initdata = {
39 .valid_hooks = MANGLE_VALID_HOOKS,
41 .size = sizeof(struct ipt_standard) * 5 + sizeof(struct ipt_error),
43 [NF_INET_PRE_ROUTING] = 0,
44 [NF_INET_LOCAL_IN] = sizeof(struct ipt_standard),
45 [NF_INET_FORWARD] = sizeof(struct ipt_standard) * 2,
46 [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 3,
47 [NF_INET_POST_ROUTING] = sizeof(struct ipt_standard) * 4,
50 [NF_INET_PRE_ROUTING] = 0,
51 [NF_INET_LOCAL_IN] = sizeof(struct ipt_standard),
52 [NF_INET_FORWARD] = sizeof(struct ipt_standard) * 2,
53 [NF_INET_LOCAL_OUT] = sizeof(struct ipt_standard) * 3,
54 [NF_INET_POST_ROUTING] = sizeof(struct ipt_standard) * 4,
58 IPT_STANDARD_INIT(NF_ACCEPT), /* PRE_ROUTING */
59 IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */
60 IPT_STANDARD_INIT(NF_ACCEPT), /* FORWARD */
61 IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */
62 IPT_STANDARD_INIT(NF_ACCEPT), /* POST_ROUTING */
64 .term = IPT_ERROR_INIT, /* ERROR */
67 static const struct xt_table packet_mangler = {
69 .valid_hooks = MANGLE_VALID_HOOKS,
72 .priority = NF_IP_PRI_MANGLE,
76 ipt_local_hook(unsigned int hook,
78 const struct net_device *in,
79 const struct net_device *out,
80 int (*okfn)(struct sk_buff *))
83 const struct iphdr *iph;
88 /* root is playing with raw sockets. */
89 if (skb->len < sizeof(struct iphdr) ||
90 ip_hdrlen(skb) < sizeof(struct iphdr))
93 /* Save things which could affect route */
100 ret = ipt_do_table(skb, hook, in, out,
101 dev_net(out)->ipv4.iptable_mangle);
102 /* Reroute for ANY change. */
103 if (ret != NF_DROP && ret != NF_STOLEN && ret != NF_QUEUE) {
106 if (iph->saddr != saddr ||
107 iph->daddr != daddr ||
110 if (ip_route_me_harder(skb, RTN_UNSPEC))
117 /* The work comes in here from netfilter.c. */
119 iptable_mangle_hook(unsigned int hook,
121 const struct net_device *in,
122 const struct net_device *out,
123 int (*okfn)(struct sk_buff *))
125 if (hook == NF_INET_LOCAL_OUT)
126 return ipt_local_hook(hook, skb, in, out, okfn);
128 /* PREROUTING/INPUT/FORWARD: */
129 return ipt_do_table(skb, hook, in, out,
130 dev_net(in)->ipv4.iptable_mangle);
133 static struct nf_hook_ops *mangle_ops __read_mostly;
135 static int __net_init iptable_mangle_net_init(struct net *net)
138 net->ipv4.iptable_mangle =
139 ipt_register_table(net, &packet_mangler, &initial_table.repl);
140 if (IS_ERR(net->ipv4.iptable_mangle))
141 return PTR_ERR(net->ipv4.iptable_mangle);
145 static void __net_exit iptable_mangle_net_exit(struct net *net)
147 ipt_unregister_table(net, net->ipv4.iptable_mangle);
150 static struct pernet_operations iptable_mangle_net_ops = {
151 .init = iptable_mangle_net_init,
152 .exit = iptable_mangle_net_exit,
155 static int __init iptable_mangle_init(void)
159 ret = register_pernet_subsys(&iptable_mangle_net_ops);
164 mangle_ops = xt_hook_link(&packet_mangler, iptable_mangle_hook);
165 if (IS_ERR(mangle_ops)) {
166 ret = PTR_ERR(mangle_ops);
173 unregister_pernet_subsys(&iptable_mangle_net_ops);
177 static void __exit iptable_mangle_fini(void)
179 xt_hook_unlink(&packet_mangler, mangle_ops);
180 unregister_pernet_subsys(&iptable_mangle_net_ops);
183 module_init(iptable_mangle_init);
184 module_exit(iptable_mangle_fini);