netfilter: ip6tables: add REDIRECT target (115e23ac) · Commits · e / devices / android_kernel_teracube_emerald

net/ipv6/netfilter/Kconfig

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		@@ -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

net/ipv6/netfilter/Makefile

+1 −0

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		@@ -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

net/ipv6/netfilter/ip6t_REDIRECT.c

0 → 100644

+98 −0

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		/*
		* 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");