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Diffstat (limited to '')
-rw-r--r-- | net/ipv4/netfilter/iptable_filter.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c new file mode 100644 index 000000000..b9062f455 --- /dev/null +++ b/net/ipv4/netfilter/iptable_filter.c @@ -0,0 +1,110 @@ +// 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 const struct xt_table packet_filter = { + .name = "filter", + .valid_hooks = FILTER_VALID_HOOKS, + .me = THIS_MODULE, + .af = NFPROTO_IPV4, + .priority = NF_IP_PRI_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 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 (!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 = xt_register_template(&packet_filter, + iptable_filter_table_init); + + if (ret < 0) + return ret; + + filter_ops = xt_hook_ops_alloc(&packet_filter, ipt_do_table); + if (IS_ERR(filter_ops)) { + xt_unregister_template(&packet_filter); + return PTR_ERR(filter_ops); + } + + ret = register_pernet_subsys(&iptable_filter_net_ops); + if (ret < 0) { + xt_unregister_template(&packet_filter); + kfree(filter_ops); + return ret; + } + + return 0; +} + +static void __exit iptable_filter_fini(void) +{ + unregister_pernet_subsys(&iptable_filter_net_ops); + xt_unregister_template(&packet_filter); + kfree(filter_ops); +} + +module_init(iptable_filter_init); +module_exit(iptable_filter_fini); |