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netfilter: ip6tables: add REDIRECT target

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Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Patrick McHardy 2012-08-26 19:14:16 +02:00 committed by Pablo Neira Ayuso
parent b3f644fc82
commit 115e23ac78
3 changed files with 110 additions and 0 deletions
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11
net/ipv6/netfilter/Kconfig
View file

@ -156,6 +156,17 @@ config IP6_NF_TARGET_MASQUERADE
To compile it as a module, choose M here. If unsure, say N.
config IP6_NF_TARGET_REDIRECT
tristate "REDIRECT target support"
depends on NF_NAT_IPV6
help
REDIRECT is a special case of NAT: all incoming connections are
mapped onto the incoming interface's address, causing the packets to
come to the local machine instead of passing through. This is
useful for transparent proxies.
To compile it as a module, choose M here. If unsure, say N.
config IP6_NF_FILTER
tristate "Packet filtering"
default m if NETFILTER_ADVANCED=n

1
net/ipv6/netfilter/Makefile
View file

@ -35,4 +35,5 @@ obj-$(CONFIG_IP6_NF_MATCH_RT) += ip6t_rt.o
# targets
obj-$(CONFIG_IP6_NF_TARGET_MASQUERADE) += ip6t_MASQUERADE.o
obj-$(CONFIG_IP6_NF_TARGET_REDIRECT) += ip6t_REDIRECT.o
obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o

98
net/ipv6/netfilter/ip6t_REDIRECT.c Normal file
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@ -0,0 +1,98 @@
/*
* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
* NAT funded by Astaro.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <net/addrconf.h>
#include <net/netfilter/nf_nat.h>
static const struct in6_addr loopback_addr = IN6ADDR_LOOPBACK_INIT;
static unsigned int
redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct nf_nat_range *range = par->targinfo;
struct nf_nat_range newrange;
struct in6_addr newdst;
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
ct = nf_ct_get(skb, &ctinfo);
if (par->hooknum == NF_INET_LOCAL_OUT)
newdst = loopback_addr;
else {
struct inet6_dev *idev;
struct inet6_ifaddr *ifa;
bool addr = false;
rcu_read_lock();
idev = __in6_dev_get(skb->dev);
if (idev != NULL) {
list_for_each_entry(ifa, &idev->addr_list, if_list) {
newdst = ifa->addr;
addr = true;
break;
}
}
rcu_read_unlock();
if (!addr)
return NF_DROP;
}
newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
newrange.min_addr.in6 = newdst;
newrange.max_addr.in6 = newdst;
newrange.min_proto = range->min_proto;
newrange.max_proto = range->max_proto;
return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
}
static int redirect_tg6_checkentry(const struct xt_tgchk_param *par)
{
const struct nf_nat_range *range = par->targinfo;
if (range->flags & NF_NAT_RANGE_MAP_IPS)
return -EINVAL;
return 0;
}
static struct xt_target redirect_tg6_reg __read_mostly = {
.name = "REDIRECT",
.family = NFPROTO_IPV6,
.checkentry = redirect_tg6_checkentry,
.target = redirect_tg6,
.targetsize = sizeof(struct nf_nat_range),
.table = "nat",
.hooks = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT),
.me = THIS_MODULE,
};
static int __init redirect_tg6_init(void)
{
return xt_register_target(&redirect_tg6_reg);
}
static void __exit redirect_tg6_exit(void)
{
xt_unregister_target(&redirect_tg6_reg);
}
module_init(redirect_tg6_init);
module_exit(redirect_tg6_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Xtables: Connection redirection to localhost");