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Commit e9105f1b authored by Arturo Borrero's avatar Arturo Borrero Committed by Pablo Neira Ayuso
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netfilter: nf_tables: add new expression nft_redir 



This new expression provides NAT in the redirect flavour, which is to
redirect packets to local machine.

Signed-off-by: default avatarArturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 9de920ed

include/net/netfilter/nft_redir.h

0 → 100644
+21 −0
Original line number Diff line number Diff line 
#ifndef _NFT_REDIR_H_

#define _NFT_REDIR_H_



struct nft_redir {

	enum nft_registers	sreg_proto_min:8;

	enum nft_registers	sreg_proto_max:8;

	u16			flags;

};



extern const struct nla_policy nft_redir_policy[];



int nft_redir_init(const struct nft_ctx *ctx,

		   const struct nft_expr *expr,

		   const struct nlattr * const tb[]);



int nft_redir_dump(struct sk_buff *skb, const struct nft_expr *expr);



int nft_redir_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,

		       const struct nft_data **data);



#endif /* _NFT_REDIR_H_ */

include/uapi/linux/netfilter/nf_tables.h

+16 −0
Original line number Diff line number Diff line
@@ -837,6 +837,22 @@ enum nft_masq_attributes { 
};

#define NFTA_MASQ_MAX		(__NFTA_MASQ_MAX - 1)



/**

 * enum nft_redir_attributes - nf_tables redirect expression netlink attributes

 *

 * @NFTA_REDIR_REG_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)

 * @NFTA_REDIR_REG_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)

 * @NFTA_REDIR_FLAGS: NAT flags (see NF_NAT_RANGE_* in linux/netfilter/nf_nat.h) (NLA_U32)

 */

enum nft_redir_attributes {

	NFTA_REDIR_UNSPEC,

	NFTA_REDIR_REG_PROTO_MIN,

	NFTA_REDIR_REG_PROTO_MAX,

	NFTA_REDIR_FLAGS,

	__NFTA_REDIR_MAX

};

#define NFTA_REDIR_MAX		(__NFTA_REDIR_MAX - 1)



/**

 * enum nft_gen_attributes - nf_tables ruleset generation attributes

 *

net/ipv4/netfilter/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -119,6 +119,15 @@ config NFT_MASQ_IPV4 
	  This is the expression that provides IPv4 masquerading support for

	  nf_tables.



config NFT_REDIR_IPV4

	tristate "IPv4 redirect support for nf_tables"

	depends on NF_TABLES_IPV4

	depends on NFT_REDIR

	select NF_NAT_REDIRECT_IPV4

	help

	  This is the expression that provides IPv4 redirect support for

	  nf_tables.



config NF_NAT_SNMP_BASIC

	tristate "Basic SNMP-ALG support"

	depends on NF_CONNTRACK_SNMP

net/ipv4/netfilter/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV4) += nft_chain_route_ipv4.o 
obj-$(CONFIG_NFT_CHAIN_NAT_IPV4) += nft_chain_nat_ipv4.o

obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_ipv4.o

obj-$(CONFIG_NFT_MASQ_IPV4) += nft_masq_ipv4.o

obj-$(CONFIG_NFT_REDIR_IPV4) += nft_redir_ipv4.o

obj-$(CONFIG_NF_TABLES_ARP) += nf_tables_arp.o



# generic IP tables

net/ipv4/netfilter/nft_redir_ipv4.c

0 → 100644
+77 −0
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/*

 * Copyright (c) 2014 Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>

 *

 * 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.

 */



#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/netlink.h>

#include <linux/netfilter.h>

#include <linux/netfilter/nf_tables.h>

#include <net/netfilter/nf_tables.h>

#include <net/netfilter/nf_nat.h>

#include <net/netfilter/ipv4/nf_nat_redirect.h>

#include <net/netfilter/nft_redir.h>



static void nft_redir_ipv4_eval(const struct nft_expr *expr,

				struct nft_data data[NFT_REG_MAX + 1],

				const struct nft_pktinfo *pkt)

{

	struct nft_redir *priv = nft_expr_priv(expr);

	struct nf_nat_ipv4_multi_range_compat mr;

	unsigned int verdict;



	memset(&mr, 0, sizeof(mr));

	if (priv->sreg_proto_min) {

		mr.range[0].min.all = (__force __be16)

					data[priv->sreg_proto_min].data[0];

		mr.range[0].max.all = (__force __be16)

					data[priv->sreg_proto_max].data[0];

		mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;

	}



	mr.range[0].flags |= priv->flags;



	verdict = nf_nat_redirect_ipv4(pkt->skb, &mr, pkt->ops->hooknum);

	data[NFT_REG_VERDICT].verdict = verdict;

}



static struct nft_expr_type nft_redir_ipv4_type;

static const struct nft_expr_ops nft_redir_ipv4_ops = {

	.type		= &nft_redir_ipv4_type,

	.size		= NFT_EXPR_SIZE(sizeof(struct nft_redir)),

	.eval		= nft_redir_ipv4_eval,

	.init		= nft_redir_init,

	.dump		= nft_redir_dump,

	.validate	= nft_redir_validate,

};



static struct nft_expr_type nft_redir_ipv4_type __read_mostly = {

	.family		= NFPROTO_IPV4,

	.name		= "redir",

	.ops		= &nft_redir_ipv4_ops,

	.policy		= nft_redir_policy,

	.maxattr	= NFTA_REDIR_MAX,

	.owner		= THIS_MODULE,

};



static int __init nft_redir_ipv4_module_init(void)

{

	return nft_register_expr(&nft_redir_ipv4_type);

}



static void __exit nft_redir_ipv4_module_exit(void)

{

	nft_unregister_expr(&nft_redir_ipv4_type);

}



module_init(nft_redir_ipv4_module_init);

module_exit(nft_redir_ipv4_module_exit);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");

MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "redir");