157 lines
3.8 KiB
C
157 lines
3.8 KiB
C
/*
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* This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
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*
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* Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
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* Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <net/ip.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
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MODULE_DESCRIPTION("iptables filter table");
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#define FILTER_VALID_HOOKS ((1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) | (1 << NF_IP_LOCAL_OUT))
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static struct
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{
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struct ipt_replace repl;
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struct ipt_standard entries[3];
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struct ipt_error term;
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} initial_table __initdata = {
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.repl = {
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.name = "filter",
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.valid_hooks = FILTER_VALID_HOOKS,
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.num_entries = 4,
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.size = sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
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.hook_entry = {
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[NF_IP_LOCAL_IN] = 0,
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[NF_IP_FORWARD] = sizeof(struct ipt_standard),
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[NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
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},
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.underflow = {
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[NF_IP_LOCAL_IN] = 0,
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[NF_IP_FORWARD] = sizeof(struct ipt_standard),
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[NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 2,
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},
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},
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.entries = {
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IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */
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IPT_STANDARD_INIT(NF_ACCEPT), /* FORWARD */
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IPT_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */
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},
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.term = IPT_ERROR_INIT, /* ERROR */
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};
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static struct xt_table packet_filter = {
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.name = "filter",
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.valid_hooks = FILTER_VALID_HOOKS,
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.lock = RW_LOCK_UNLOCKED,
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.me = THIS_MODULE,
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.af = AF_INET,
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};
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/* The work comes in here from netfilter.c. */
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static unsigned int
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ipt_hook(unsigned int hook,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return ipt_do_table(skb, hook, in, out, &packet_filter);
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}
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static unsigned int
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ipt_local_out_hook(unsigned int hook,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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/* root is playing with raw sockets. */
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if (skb->len < sizeof(struct iphdr) ||
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ip_hdrlen(skb) < sizeof(struct iphdr)) {
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if (net_ratelimit())
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printk("iptable_filter: ignoring short SOCK_RAW "
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"packet.\n");
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return NF_ACCEPT;
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}
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return ipt_do_table(skb, hook, in, out, &packet_filter);
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}
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static struct nf_hook_ops ipt_ops[] = {
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{
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.hook = ipt_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_IP_LOCAL_IN,
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.priority = NF_IP_PRI_FILTER,
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},
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{
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.hook = ipt_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_IP_FORWARD,
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.priority = NF_IP_PRI_FILTER,
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},
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{
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.hook = ipt_local_out_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET,
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.hooknum = NF_IP_LOCAL_OUT,
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.priority = NF_IP_PRI_FILTER,
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},
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};
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/* Default to forward because I got too much mail already. */
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static int forward = NF_ACCEPT;
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module_param(forward, bool, 0000);
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static int __init iptable_filter_init(void)
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{
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int ret;
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if (forward < 0 || forward > NF_MAX_VERDICT) {
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printk("iptables forward must be 0 or 1\n");
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return -EINVAL;
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}
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/* Entry 1 is the FORWARD hook */
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initial_table.entries[1].target.verdict = -forward - 1;
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/* Register table */
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ret = ipt_register_table(&packet_filter, &initial_table.repl);
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if (ret < 0)
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return ret;
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/* Register hooks */
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ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
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if (ret < 0)
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goto cleanup_table;
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return ret;
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cleanup_table:
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ipt_unregister_table(&packet_filter);
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return ret;
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}
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static void __exit iptable_filter_fini(void)
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{
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nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops));
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ipt_unregister_table(&packet_filter);
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}
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module_init(iptable_filter_init);
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module_exit(iptable_filter_fini);
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