ip6table_filter.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
  4 *
  5 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  6 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
  7 */
  8
  9#include <linux/module.h>
 10#include <linux/moduleparam.h>
 11#include <linux/netfilter_ipv6/ip6_tables.h>
 12#include <linux/slab.h>
 13
 14MODULE_LICENSE("GPL");
 15MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 16MODULE_DESCRIPTION("ip6tables filter table");
 17
 18#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
 19			    (1 << NF_INET_FORWARD) | \
 20			    (1 << NF_INET_LOCAL_OUT))
 21
 22static const struct xt_table packet_filter = {
 23	.name		= "filter",
 24	.valid_hooks	= FILTER_VALID_HOOKS,
 25	.me		= THIS_MODULE,
 26	.af		= NFPROTO_IPV6,
 27	.priority	= NF_IP6_PRI_FILTER,
 28};
 29
 30static struct nf_hook_ops *filter_ops __read_mostly;
 31
 32/* Default to forward because I got too much mail already. */
 33static bool forward = true;
 34module_param(forward, bool, 0000);
 35
 36static int ip6table_filter_table_init(struct net *net)
 37{
 38	struct ip6t_replace *repl;
 39	int err;
 40
 41	repl = ip6t_alloc_initial_table(&packet_filter);
 42	if (repl == NULL)
 43		return -ENOMEM;
 44	/* Entry 1 is the FORWARD hook */
 45	((struct ip6t_standard *)repl->entries)[1].target.verdict =
 46		forward ? -NF_ACCEPT - 1 : NF_DROP - 1;
 47
 48	err = ip6t_register_table(net, &packet_filter, repl, filter_ops);
 49	kfree(repl);
 50	return err;
 51}
 52
 53static int __net_init ip6table_filter_net_init(struct net *net)
 54{
 55	if (!forward)
 56		return ip6table_filter_table_init(net);
 57
 58	return 0;
 59}
 60
 61static void __net_exit ip6table_filter_net_pre_exit(struct net *net)
 62{
 63	ip6t_unregister_table_pre_exit(net, "filter");
 64}
 65
 66static void __net_exit ip6table_filter_net_exit(struct net *net)
 67{
 68	ip6t_unregister_table_exit(net, "filter");
 69}
 70
 71static struct pernet_operations ip6table_filter_net_ops = {
 72	.init = ip6table_filter_net_init,
 73	.pre_exit = ip6table_filter_net_pre_exit,
 74	.exit = ip6table_filter_net_exit,
 75};
 76
 77static int __init ip6table_filter_init(void)
 78{
 79	int ret = xt_register_template(&packet_filter,
 80					ip6table_filter_table_init);
 81
 82	if (ret < 0)
 83		return ret;
 84
 85	filter_ops = xt_hook_ops_alloc(&packet_filter, ip6t_do_table);
 86	if (IS_ERR(filter_ops)) {
 87		xt_unregister_template(&packet_filter);
 88		return PTR_ERR(filter_ops);
 89	}
 90
 91	ret = register_pernet_subsys(&ip6table_filter_net_ops);
 92	if (ret < 0) {
 93		xt_unregister_template(&packet_filter);
 94		kfree(filter_ops);
 95		return ret;
 96	}
 97
 98	return ret;
 99}
100
101static void __exit ip6table_filter_fini(void)
102{
103	unregister_pernet_subsys(&ip6table_filter_net_ops);
104	xt_unregister_template(&packet_filter);
105	kfree(filter_ops);
106}
107
108module_init(ip6table_filter_init);
109module_exit(ip6table_filter_fini);