// SPDX-License-Identifier: GPL-2.0-only
|
/*
|
* 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>
|
*/
|
|
#include <linux/module.h>
|
#include <linux/moduleparam.h>
|
#include <linux/netfilter_ipv4/ip_tables.h>
|
#include <linux/slab.h>
|
#include <net/ip.h>
|
|
MODULE_LICENSE("GPL");
|
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
|
MODULE_DESCRIPTION("iptables filter table");
|
|
#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
|
(1 << NF_INET_FORWARD) | \
|
(1 << NF_INET_LOCAL_OUT))
|
static int __net_init iptable_filter_table_init(struct net *net);
|
|
static const struct xt_table packet_filter = {
|
.name = "filter",
|
.valid_hooks = FILTER_VALID_HOOKS,
|
.me = THIS_MODULE,
|
.af = NFPROTO_IPV4,
|
.priority = NF_IP_PRI_FILTER,
|
.table_init = iptable_filter_table_init,
|
};
|
|
static unsigned int
|
iptable_filter_hook(void *priv, struct sk_buff *skb,
|
const struct nf_hook_state *state)
|
{
|
return ipt_do_table(skb, state, state->net->ipv4.iptable_filter);
|
}
|
|
static struct nf_hook_ops *filter_ops __read_mostly;
|
|
/* Default to forward because I got too much mail already. */
|
static bool forward __read_mostly = true;
|
module_param(forward, bool, 0000);
|
|
static int __net_init iptable_filter_table_init(struct net *net)
|
{
|
struct ipt_replace *repl;
|
int err;
|
|
if (net->ipv4.iptable_filter)
|
return 0;
|
|
repl = ipt_alloc_initial_table(&packet_filter);
|
if (repl == NULL)
|
return -ENOMEM;
|
/* Entry 1 is the FORWARD hook */
|
((struct ipt_standard *)repl->entries)[1].target.verdict =
|
forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
|
|
err = ipt_register_table(net, &packet_filter, repl, filter_ops,
|
&net->ipv4.iptable_filter);
|
kfree(repl);
|
return err;
|
}
|
|
static int __net_init iptable_filter_net_init(struct net *net)
|
{
|
if (net == &init_net || !forward)
|
return iptable_filter_table_init(net);
|
|
return 0;
|
}
|
|
static void __net_exit iptable_filter_net_pre_exit(struct net *net)
|
{
|
if (net->ipv4.iptable_filter)
|
ipt_unregister_table_pre_exit(net, net->ipv4.iptable_filter,
|
filter_ops);
|
}
|
|
static void __net_exit iptable_filter_net_exit(struct net *net)
|
{
|
if (!net->ipv4.iptable_filter)
|
return;
|
ipt_unregister_table_exit(net, net->ipv4.iptable_filter);
|
net->ipv4.iptable_filter = NULL;
|
}
|
|
static struct pernet_operations iptable_filter_net_ops = {
|
.init = iptable_filter_net_init,
|
.pre_exit = iptable_filter_net_pre_exit,
|
.exit = iptable_filter_net_exit,
|
};
|
|
static int __init iptable_filter_init(void)
|
{
|
int ret;
|
|
filter_ops = xt_hook_ops_alloc(&packet_filter, iptable_filter_hook);
|
if (IS_ERR(filter_ops))
|
return PTR_ERR(filter_ops);
|
|
ret = register_pernet_subsys(&iptable_filter_net_ops);
|
if (ret < 0)
|
kfree(filter_ops);
|
|
return ret;
|
}
|
|
static void __exit iptable_filter_fini(void)
|
{
|
unregister_pernet_subsys(&iptable_filter_net_ops);
|
kfree(filter_ops);
|
}
|
|
module_init(iptable_filter_init);
|
module_exit(iptable_filter_fini);
|
