cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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iptable_filter.c (2720B)

      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_ipv4/ip_tables.h>
     12#include <linux/slab.h>
     13#include <net/ip.h>
     14
     15MODULE_LICENSE("GPL");
     16MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
     17MODULE_DESCRIPTION("iptables filter table");
     18
     19#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
     20			    (1 << NF_INET_FORWARD) | \
     21			    (1 << NF_INET_LOCAL_OUT))
     22
     23static const struct xt_table packet_filter = {
     24	.name		= "filter",
     25	.valid_hooks	= FILTER_VALID_HOOKS,
     26	.me		= THIS_MODULE,
     27	.af		= NFPROTO_IPV4,
     28	.priority	= NF_IP_PRI_FILTER,
     29};
     30
     31static struct nf_hook_ops *filter_ops __read_mostly;
     32
     33/* Default to forward because I got too much mail already. */
     34static bool forward __read_mostly = true;
     35module_param(forward, bool, 0000);
     36
     37static int iptable_filter_table_init(struct net *net)
     38{
     39	struct ipt_replace *repl;
     40	int err;
     41
     42	repl = ipt_alloc_initial_table(&packet_filter);
     43	if (repl == NULL)
     44		return -ENOMEM;
     45	/* Entry 1 is the FORWARD hook */
     46	((struct ipt_standard *)repl->entries)[1].target.verdict =
     47		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
     48
     49	err = ipt_register_table(net, &packet_filter, repl, filter_ops);
     50	kfree(repl);
     51	return err;
     52}
     53
     54static int __net_init iptable_filter_net_init(struct net *net)
     55{
     56	if (!forward)
     57		return iptable_filter_table_init(net);
     58
     59	return 0;
     60}
     61
     62static void __net_exit iptable_filter_net_pre_exit(struct net *net)
     63{
     64	ipt_unregister_table_pre_exit(net, "filter");
     65}
     66
     67static void __net_exit iptable_filter_net_exit(struct net *net)
     68{
     69	ipt_unregister_table_exit(net, "filter");
     70}
     71
     72static struct pernet_operations iptable_filter_net_ops = {
     73	.init = iptable_filter_net_init,
     74	.pre_exit = iptable_filter_net_pre_exit,
     75	.exit = iptable_filter_net_exit,
     76};
     77
     78static int __init iptable_filter_init(void)
     79{
     80	int ret = xt_register_template(&packet_filter,
     81				       iptable_filter_table_init);
     82
     83	if (ret < 0)
     84		return ret;
     85
     86	filter_ops = xt_hook_ops_alloc(&packet_filter, ipt_do_table);
     87	if (IS_ERR(filter_ops)) {
     88		xt_unregister_template(&packet_filter);
     89		return PTR_ERR(filter_ops);
     90	}
     91
     92	ret = register_pernet_subsys(&iptable_filter_net_ops);
     93	if (ret < 0) {
     94		xt_unregister_template(&packet_filter);
     95		kfree(filter_ops);
     96		return ret;
     97	}
     98
     99	return 0;
    100}
    101
    102static void __exit iptable_filter_fini(void)
    103{
    104	unregister_pernet_subsys(&iptable_filter_net_ops);
    105	xt_unregister_template(&packet_filter);
    106	kfree(filter_ops);
    107}
    108
    109module_init(iptable_filter_init);
    110module_exit(iptable_filter_fini);