123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178 |
- /*
- * 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>
- 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
- = { { "filter", FILTER_VALID_HOOKS, 4,
- sizeof(struct ipt_standard) * 3 + sizeof(struct ipt_error),
- { [NF_IP_LOCAL_IN] = 0,
- [NF_IP_FORWARD] = sizeof(struct ipt_standard),
- [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 2 },
- { [NF_IP_LOCAL_IN] = 0,
- [NF_IP_FORWARD] = sizeof(struct ipt_standard),
- [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 2 },
- 0, NULL, { } },
- {
- /* LOCAL_IN */
- { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
- 0,
- sizeof(struct ipt_entry),
- sizeof(struct ipt_standard),
- 0, { 0, 0 }, { } },
- { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
- -NF_ACCEPT - 1 } },
- /* FORWARD */
- { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
- 0,
- sizeof(struct ipt_entry),
- sizeof(struct ipt_standard),
- 0, { 0, 0 }, { } },
- { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
- -NF_ACCEPT - 1 } },
- /* LOCAL_OUT */
- { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
- 0,
- sizeof(struct ipt_entry),
- sizeof(struct ipt_standard),
- 0, { 0, 0 }, { } },
- { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } },
- -NF_ACCEPT - 1 } }
- },
- /* ERROR */
- { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 },
- 0,
- sizeof(struct ipt_entry),
- sizeof(struct ipt_error),
- 0, { 0, 0 }, { } },
- { { { { IPT_ALIGN(sizeof(struct ipt_error_target)), IPT_ERROR_TARGET } },
- { } },
- "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)
- || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
- if (net_ratelimit())
- printk("ipt_hook: happy cracking.\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);
|