xt_REDIRECT.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
*
* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
* NAT funded by Astaro.
*/
#include <linux/if.h>
#include <linux/inetdevice.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/types.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <net/addrconf.h>
#include <net/checksum.h>
#include <net/protocol.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_redirect.h>
static unsigned int
redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
return nf_nat_redirect_ipv6(skb, par->targinfo, xt_hooknum(par));
}
static int redirect_tg6_checkentry(const struct xt_tgchk_param *par)
{
const struct nf_nat_range2 *range = par->targinfo;
if (range->flags & NF_NAT_RANGE_MAP_IPS)
return -EINVAL;
return nf_ct_netns_get(par->net, par->family);
}
static void redirect_tg_destroy(const struct xt_tgdtor_param *par)
{
nf_ct_netns_put(par->net, par->family);
}
static int redirect_tg4_check(const struct xt_tgchk_param *par)
{
const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) {
pr_debug("bad MAP_IPS.\n");
return -EINVAL;
}
if (mr->rangesize != 1) {
pr_debug("bad rangesize %u.\n", mr->rangesize);
return -EINVAL;
}
return nf_ct_netns_get(par->net, par->family);
}
static unsigned int
redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
struct nf_nat_range2 range = {
.flags = mr->range[0].flags,
.min_proto = mr->range[0].min,
.max_proto = mr->range[0].max,
};
return nf_nat_redirect_ipv4(skb, &range, xt_hooknum(par));
}
static struct xt_target redirect_tg_reg[] __read_mostly = {
{
.name = "REDIRECT",
.family = NFPROTO_IPV6,
.revision = 0,
.table = "nat",
.checkentry = redirect_tg6_checkentry,
.destroy = redirect_tg_destroy,
.target = redirect_tg6,
.targetsize = sizeof(struct nf_nat_range),
.hooks = (1 << NF_INET_PRE_ROUTING) |
(1 << NF_INET_LOCAL_OUT),
.me = THIS_MODULE,
},
{
.name = "REDIRECT",
.family = NFPROTO_IPV4,
.revision = 0,
.table = "nat",
.target = redirect_tg4,
.checkentry = redirect_tg4_check,
.destroy = redirect_tg_destroy,
.targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
.hooks = (1 << NF_INET_PRE_ROUTING) |
(1 << NF_INET_LOCAL_OUT),
.me = THIS_MODULE,
},
};
static int __init redirect_tg_init(void)
{
return xt_register_targets(redirect_tg_reg,
ARRAY_SIZE(redirect_tg_reg));
}
static void __exit redirect_tg_exit(void)
{
xt_unregister_targets(redirect_tg_reg, ARRAY_SIZE(redirect_tg_reg));
}
module_init(redirect_tg_init);
module_exit(redirect_tg_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Xtables: Connection redirection to localhost");
MODULE_ALIAS("ip6t_REDIRECT");
MODULE_ALIAS("ipt_REDIRECT");