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Commit 502061f8 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
Browse files

netfilter: nf_tables: add packet duplication to the netdev family 



You can use this to duplicate packets and inject them at the egress path
of the specified interface. This duplication allows you to inspect
traffic from the dummy or any other interface dedicated to this purpose.

Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent c7862a5f

include/net/netfilter/nf_dup_netdev.h

0 → 100644
+6 −0
Original line number Diff line number Diff line 
#ifndef _NF_DUP_NETDEV_H_

#define _NF_DUP_NETDEV_H_



void nf_dup_netdev_egress(const struct nft_pktinfo *pkt, int oif);



#endif

net/netfilter/Kconfig

+16 −0
Original line number Diff line number Diff line
@@ -563,6 +563,22 @@ config NFT_COMPAT 
	  x_tables match/target extensions over the nf_tables

	  framework.



if NF_TABLES_NETDEV



config NF_DUP_NETDEV

	tristate "Netfilter packet duplication support"

	help

	  This option enables the generic packet duplication infrastructure

	  for Netfilter.



config NFT_DUP_NETDEV

	tristate "Netfilter nf_tables netdev packet duplication support"

	select NF_DUP_NETDEV

	help

	  This option enables packet duplication for the "netdev" family.



endif # NF_TABLES_NETDEV



endif # NF_TABLES



config NETFILTER_XTABLES

net/netfilter/Makefile

+6 −0
Original line number Diff line number Diff line
@@ -66,6 +66,9 @@ obj-$(CONFIG_NF_NAT_TFTP) += nf_nat_tftp.o 
# SYNPROXY

obj-$(CONFIG_NETFILTER_SYNPROXY) += nf_synproxy_core.o



# generic packet duplication from netdev family

obj-$(CONFIG_NF_DUP_NETDEV)	+= nf_dup_netdev.o



# nf_tables

nf_tables-objs += nf_tables_core.o nf_tables_api.o nf_tables_trace.o

nf_tables-objs += nft_immediate.o nft_cmp.o nft_lookup.o nft_dynset.o
@@ -90,6 +93,9 @@ obj-$(CONFIG_NFT_LOG) += nft_log.o 
obj-$(CONFIG_NFT_MASQ)		+= nft_masq.o

obj-$(CONFIG_NFT_REDIR)		+= nft_redir.o



# nf_tables netdev

obj-$(CONFIG_NFT_DUP_NETDEV)	+= nft_dup_netdev.o



# generic X tables 

obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o

net/netfilter/nf_dup_netdev.c

0 → 100644
+40 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>

 *

 * 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>



void nf_dup_netdev_egress(const struct nft_pktinfo *pkt, int oif)

{

	struct net_device *dev;

	struct sk_buff *skb;



	dev = dev_get_by_index_rcu(pkt->net, oif);

	if (dev == NULL)

		return;



	skb = skb_clone(pkt->skb, GFP_ATOMIC);

	if (skb == NULL)

		return;



	if (skb_mac_header_was_set(skb))

		skb_push(skb, skb->mac_len);



	skb->dev = dev;

	skb_sender_cpu_clear(skb);

	dev_queue_xmit(skb);

}

EXPORT_SYMBOL_GPL(nf_dup_netdev_egress);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");

net/netfilter/nft_dup_netdev.c

0 → 100644
+97 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>

 *

 * 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_dup_netdev.h>



struct nft_dup_netdev {

	enum nft_registers	sreg_dev:8;

};



static void nft_dup_netdev_eval(const struct nft_expr *expr,

				struct nft_regs *regs,

				const struct nft_pktinfo *pkt)

{

	struct nft_dup_netdev *priv = nft_expr_priv(expr);

	int oif = regs->data[priv->sreg_dev];



	nf_dup_netdev_egress(pkt, oif);

}



static const struct nla_policy nft_dup_netdev_policy[NFTA_DUP_MAX + 1] = {

	[NFTA_DUP_SREG_DEV]	= { .type = NLA_U32 },

};



static int nft_dup_netdev_init(const struct nft_ctx *ctx,

			       const struct nft_expr *expr,

			       const struct nlattr * const tb[])

{

	struct nft_dup_netdev *priv = nft_expr_priv(expr);



	if (tb[NFTA_DUP_SREG_DEV] == NULL)

		return -EINVAL;



	priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);

	return nft_validate_register_load(priv->sreg_dev, sizeof(int));

}



static const struct nft_expr_ops nft_dup_netdev_ingress_ops;



static int nft_dup_netdev_dump(struct sk_buff *skb, const struct nft_expr *expr)

{

	struct nft_dup_netdev *priv = nft_expr_priv(expr);



	if (nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))

		goto nla_put_failure;



	return 0;



nla_put_failure:

	return -1;

}



static struct nft_expr_type nft_dup_netdev_type;

static const struct nft_expr_ops nft_dup_netdev_ops = {

	.type		= &nft_dup_netdev_type,

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

	.eval		= nft_dup_netdev_eval,

	.init		= nft_dup_netdev_init,

	.dump		= nft_dup_netdev_dump,

};



static struct nft_expr_type nft_dup_netdev_type __read_mostly = {

	.family		= NFPROTO_NETDEV,

	.name		= "dup",

	.ops		= &nft_dup_netdev_ops,

	.policy		= nft_dup_netdev_policy,

	.maxattr	= NFTA_DUP_MAX,

	.owner		= THIS_MODULE,

};



static int __init nft_dup_netdev_module_init(void)

{

	return nft_register_expr(&nft_dup_netdev_type);

}



static void __exit nft_dup_netdev_module_exit(void)

{

	nft_unregister_expr(&nft_dup_netdev_type);

}



module_init(nft_dup_netdev_module_init);

module_exit(nft_dup_netdev_module_exit);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");

MODULE_ALIAS_NFT_AF_EXPR(5, "dup");