| // 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, priv); |
| } |
| |
| 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; |
| |
| 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); |
| 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) |
| { |
| ipt_unregister_table_pre_exit(net, "filter"); |
| } |
| |
| static void __net_exit iptable_filter_net_exit(struct net *net) |
| { |
| ipt_unregister_table_exit(net, "filter"); |
| } |
| |
| 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); |