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