iptable_raw.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
  4 *
  5 * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@netfilter.org>
  6 */
  7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  8#include <linux/module.h>
  9#include <linux/netfilter_ipv4/ip_tables.h>
 10#include <linux/slab.h>
 11#include <net/ip.h>
 12
 13#define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
 14
 15static bool raw_before_defrag __read_mostly;
 16MODULE_PARM_DESC(raw_before_defrag, "Enable raw table before defrag");
 17module_param(raw_before_defrag, bool, 0000);
 18
 19static const struct xt_table packet_raw = {
 20	.name = "raw",
 21	.valid_hooks =  RAW_VALID_HOOKS,
 22	.me = THIS_MODULE,
 23	.af = NFPROTO_IPV4,
 24	.priority = NF_IP_PRI_RAW,
 25};
 26
 27static const struct xt_table packet_raw_before_defrag = {
 28	.name = "raw",
 29	.valid_hooks =  RAW_VALID_HOOKS,
 30	.me = THIS_MODULE,
 31	.af = NFPROTO_IPV4,
 32	.priority = NF_IP_PRI_RAW_BEFORE_DEFRAG,
 33};
 34
 35static struct nf_hook_ops *rawtable_ops __read_mostly;
 36
 37static int iptable_raw_table_init(struct net *net)
 38{
 39	struct ipt_replace *repl;
 40	const struct xt_table *table = &packet_raw;
 41	int ret;
 42
 43	if (raw_before_defrag)
 44		table = &packet_raw_before_defrag;
 45
 46	repl = ipt_alloc_initial_table(table);
 47	if (repl == NULL)
 48		return -ENOMEM;
 49	ret = ipt_register_table(net, table, repl, rawtable_ops);
 50	kfree(repl);
 51	return ret;
 52}
 53
 54static void __net_exit iptable_raw_net_pre_exit(struct net *net)
 55{
 56	ipt_unregister_table_pre_exit(net, "raw");
 57}
 58
 59static void __net_exit iptable_raw_net_exit(struct net *net)
 60{
 61	ipt_unregister_table_exit(net, "raw");
 62}
 63
 64static struct pernet_operations iptable_raw_net_ops = {
 65	.pre_exit = iptable_raw_net_pre_exit,
 66	.exit = iptable_raw_net_exit,
 67};
 68
 69static int __init iptable_raw_init(void)
 70{
 71	int ret;
 72	const struct xt_table *table = &packet_raw;
 73
 74	if (raw_before_defrag) {
 75		table = &packet_raw_before_defrag;
 76
 77		pr_info("Enabling raw table before defrag\n");
 78	}
 79
 80	ret = xt_register_template(table,
 81				   iptable_raw_table_init);
 82	if (ret < 0)
 83		return ret;
 84
 85	rawtable_ops = xt_hook_ops_alloc(table, ipt_do_table);
 86	if (IS_ERR(rawtable_ops)) {
 87		xt_unregister_template(table);
 88		return PTR_ERR(rawtable_ops);
 89	}
 90
 91	ret = register_pernet_subsys(&iptable_raw_net_ops);
 92	if (ret < 0) {
 93		xt_unregister_template(table);
 94		kfree(rawtable_ops);
 95		return ret;
 96	}
 97
 98	return ret;
 99}
100
101static void __exit iptable_raw_fini(void)
102{
103	unregister_pernet_subsys(&iptable_raw_net_ops);
104	kfree(rawtable_ops);
105	xt_unregister_template(&packet_raw);
106}
107
108module_init(iptable_raw_init);
109module_exit(iptable_raw_fini);
110MODULE_LICENSE("GPL");
111MODULE_DESCRIPTION("iptables legacy raw table");