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_nat.c (3708B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* (C) 1999-2001 Paul `Rusty' Russell
      3 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
      4 * (C) 2011 Patrick McHardy <kaber@trash.net>
      5 */
      6
      7#include <linux/module.h>
      8#include <linux/netfilter.h>
      9#include <linux/netfilter_ipv4.h>
     10#include <linux/netfilter_ipv4/ip_tables.h>
     11#include <linux/ip.h>
     12#include <net/ip.h>
     13
     14#include <net/netfilter/nf_nat.h>
     15
     16struct iptable_nat_pernet {
     17	struct nf_hook_ops *nf_nat_ops;
     18};
     19
     20static unsigned int iptable_nat_net_id __read_mostly;
     21
     22static const struct xt_table nf_nat_ipv4_table = {
     23	.name		= "nat",
     24	.valid_hooks	= (1 << NF_INET_PRE_ROUTING) |
     25			  (1 << NF_INET_POST_ROUTING) |
     26			  (1 << NF_INET_LOCAL_OUT) |
     27			  (1 << NF_INET_LOCAL_IN),
     28	.me		= THIS_MODULE,
     29	.af		= NFPROTO_IPV4,
     30};
     31
     32static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
     33	{
     34		.hook		= ipt_do_table,
     35		.pf		= NFPROTO_IPV4,
     36		.hooknum	= NF_INET_PRE_ROUTING,
     37		.priority	= NF_IP_PRI_NAT_DST,
     38	},
     39	{
     40		.hook		= ipt_do_table,
     41		.pf		= NFPROTO_IPV4,
     42		.hooknum	= NF_INET_POST_ROUTING,
     43		.priority	= NF_IP_PRI_NAT_SRC,
     44	},
     45	{
     46		.hook		= ipt_do_table,
     47		.pf		= NFPROTO_IPV4,
     48		.hooknum	= NF_INET_LOCAL_OUT,
     49		.priority	= NF_IP_PRI_NAT_DST,
     50	},
     51	{
     52		.hook		= ipt_do_table,
     53		.pf		= NFPROTO_IPV4,
     54		.hooknum	= NF_INET_LOCAL_IN,
     55		.priority	= NF_IP_PRI_NAT_SRC,
     56	},
     57};
     58
     59static int ipt_nat_register_lookups(struct net *net)
     60{
     61	struct iptable_nat_pernet *xt_nat_net;
     62	struct nf_hook_ops *ops;
     63	struct xt_table *table;
     64	int i, ret;
     65
     66	xt_nat_net = net_generic(net, iptable_nat_net_id);
     67	table = xt_find_table(net, NFPROTO_IPV4, "nat");
     68	if (WARN_ON_ONCE(!table))
     69		return -ENOENT;
     70
     71	ops = kmemdup(nf_nat_ipv4_ops, sizeof(nf_nat_ipv4_ops), GFP_KERNEL);
     72	if (!ops)
     73		return -ENOMEM;
     74
     75	for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
     76		ops[i].priv = table;
     77		ret = nf_nat_ipv4_register_fn(net, &ops[i]);
     78		if (ret) {
     79			while (i)
     80				nf_nat_ipv4_unregister_fn(net, &ops[--i]);
     81
     82			kfree(ops);
     83			return ret;
     84		}
     85	}
     86
     87	xt_nat_net->nf_nat_ops = ops;
     88	return 0;
     89}
     90
     91static void ipt_nat_unregister_lookups(struct net *net)
     92{
     93	struct iptable_nat_pernet *xt_nat_net = net_generic(net, iptable_nat_net_id);
     94	struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops;
     95	int i;
     96
     97	if (!ops)
     98		return;
     99
    100	for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
    101		nf_nat_ipv4_unregister_fn(net, &ops[i]);
    102
    103	kfree(ops);
    104}
    105
    106static int iptable_nat_table_init(struct net *net)
    107{
    108	struct ipt_replace *repl;
    109	int ret;
    110
    111	repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
    112	if (repl == NULL)
    113		return -ENOMEM;
    114
    115	ret = ipt_register_table(net, &nf_nat_ipv4_table, repl, NULL);
    116	if (ret < 0) {
    117		kfree(repl);
    118		return ret;
    119	}
    120
    121	ret = ipt_nat_register_lookups(net);
    122	if (ret < 0)
    123		ipt_unregister_table_exit(net, "nat");
    124
    125	kfree(repl);
    126	return ret;
    127}
    128
    129static void __net_exit iptable_nat_net_pre_exit(struct net *net)
    130{
    131	ipt_nat_unregister_lookups(net);
    132}
    133
    134static void __net_exit iptable_nat_net_exit(struct net *net)
    135{
    136	ipt_unregister_table_exit(net, "nat");
    137}
    138
    139static struct pernet_operations iptable_nat_net_ops = {
    140	.pre_exit = iptable_nat_net_pre_exit,
    141	.exit	= iptable_nat_net_exit,
    142	.id	= &iptable_nat_net_id,
    143	.size	= sizeof(struct iptable_nat_pernet),
    144};
    145
    146static int __init iptable_nat_init(void)
    147{
    148	int ret = xt_register_template(&nf_nat_ipv4_table,
    149				       iptable_nat_table_init);
    150
    151	if (ret < 0)
    152		return ret;
    153
    154	ret = register_pernet_subsys(&iptable_nat_net_ops);
    155	if (ret < 0) {
    156		xt_unregister_template(&nf_nat_ipv4_table);
    157		return ret;
    158	}
    159
    160	return ret;
    161}
    162
    163static void __exit iptable_nat_exit(void)
    164{
    165	unregister_pernet_subsys(&iptable_nat_net_ops);
    166	xt_unregister_template(&nf_nat_ipv4_table);
    167}
    168
    169module_init(iptable_nat_init);
    170module_exit(iptable_nat_exit);
    171
    172MODULE_LICENSE("GPL");