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Commit b4164998 authored by Jan Engelhardt's avatar Jan Engelhardt Committed by David S. Miller
Browse files

[NETFILTER]: xt_conntrack: add port and direction matching 



Extend the xt_conntrack match revision 1 by port matching (all four
{orig,repl}{src,dst}) and by packet direction matching.

Signed-off-by: default avatarJan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 41d0cded

include/linux/netfilter/xt_conntrack.h

+18 −12
Original line number Diff line number Diff line
@@ -6,9 +6,6 @@ 
#define _XT_CONNTRACK_H



#include <linux/netfilter/nf_conntrack_tuple_common.h>

#ifdef __KERNEL__

#	include <linux/in.h>

#endif



#define XT_CONNTRACK_STATE_BIT(ctinfo) (1 << ((ctinfo)%IP_CT_IS_REPLY+1))

#define XT_CONNTRACK_STATE_INVALID (1 << 0)
@@ -18,14 +15,21 @@ 
#define XT_CONNTRACK_STATE_UNTRACKED (1 << (IP_CT_NUMBER + 3))



/* flags, invflags: */

#define XT_CONNTRACK_STATE	0x01

#define XT_CONNTRACK_PROTO	0x02

#define XT_CONNTRACK_ORIGSRC	0x04

#define XT_CONNTRACK_ORIGDST	0x08

#define XT_CONNTRACK_REPLSRC	0x10

#define XT_CONNTRACK_REPLDST	0x20

#define XT_CONNTRACK_STATUS	0x40

#define XT_CONNTRACK_EXPIRES	0x80

enum {

	XT_CONNTRACK_STATE        = 1 << 0,

	XT_CONNTRACK_PROTO        = 1 << 1,

	XT_CONNTRACK_ORIGSRC      = 1 << 2,

	XT_CONNTRACK_ORIGDST      = 1 << 3,

	XT_CONNTRACK_REPLSRC      = 1 << 4,

	XT_CONNTRACK_REPLDST      = 1 << 5,

	XT_CONNTRACK_STATUS       = 1 << 6,

	XT_CONNTRACK_EXPIRES      = 1 << 7,

	XT_CONNTRACK_ORIGSRC_PORT = 1 << 8,

	XT_CONNTRACK_ORIGDST_PORT = 1 << 9,

	XT_CONNTRACK_REPLSRC_PORT = 1 << 10,

	XT_CONNTRACK_REPLDST_PORT = 1 << 11,

	XT_CONNTRACK_DIRECTION    = 1 << 12,

};



/* This is exposed to userspace, so remains frozen in time. */

struct ip_conntrack_old_tuple
@@ -70,8 +74,10 @@ struct xt_conntrack_mtinfo1 { 
	union nf_inet_addr repldst_addr, repldst_mask;

	u_int32_t expires_min, expires_max;

	u_int16_t l4proto;

	__be16 origsrc_port, origdst_port;

	__be16 replsrc_port, repldst_port;

	u_int16_t match_flags, invert_flags;

	u_int8_t state_mask, status_mask;

	u_int8_t match_flags, invert_flags;

};



#endif /*_XT_CONNTRACK_H*/

net/netfilter/xt_conntrack.c

+45 −5
Original line number Diff line number Diff line
@@ -4,7 +4,6 @@ 
 *

 *	(C) 2001  Marc Boucher (marc@mbsi.ca).

 *	Copyright © CC Computer Consultants GmbH, 2007 - 2008

 *	Jan Engelhardt <jengelh@computergmbh.de>

 *

 *	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
@@ -20,6 +19,7 @@ 


MODULE_LICENSE("GPL");

MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");

MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");

MODULE_DESCRIPTION("Xtables: connection tracking state match");

MODULE_ALIAS("ipt_conntrack");

MODULE_ALIAS("ip6t_conntrack");
@@ -166,6 +166,44 @@ conntrack_mt_repldst(const struct nf_conn *ct, 
	       &info->repldst_addr, &info->repldst_mask, family);

}



static inline bool

ct_proto_port_check(const struct xt_conntrack_mtinfo1 *info,

                    const struct nf_conn *ct)

{

	const struct nf_conntrack_tuple *tuple;



	tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;

	if ((info->match_flags & XT_CONNTRACK_PROTO) &&

	    (tuple->dst.protonum == info->l4proto) ^

	    !(info->invert_flags & XT_CONNTRACK_PROTO))

		return false;



	/* Shortcut to match all recognized protocols by using ->src.all. */

	if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) &&

	    (tuple->src.u.all == info->origsrc_port) ^

	    !(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT))

		return false;



	if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) &&

	    (tuple->dst.u.all == info->origdst_port) ^

	    !(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT))

		return false;



	tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;



	if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) &&

	    (tuple->src.u.all == info->replsrc_port) ^

	    !(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT))

		return false;



	if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) &&

	    (tuple->dst.u.all == info->repldst_port) ^

	    !(info->invert_flags & XT_CONNTRACK_REPLDST_PORT))

		return false;



	return true;

}



static bool

conntrack_mt(const struct sk_buff *skb, const struct net_device *in,

             const struct net_device *out, const struct xt_match *match,
@@ -200,10 +238,9 @@ conntrack_mt(const struct sk_buff *skb, const struct net_device *in, 


	if (ct == NULL)

		return info->match_flags & XT_CONNTRACK_STATE;



	if ((info->match_flags & XT_CONNTRACK_PROTO) &&

	    ((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==

	    info->l4proto) ^ !(info->invert_flags & XT_CONNTRACK_PROTO)))

	if ((info->match_flags & XT_CONNTRACK_DIRECTION) &&

	    (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^

	    !!(info->invert_flags & XT_CONNTRACK_DIRECTION))

		return false;



	if (info->match_flags & XT_CONNTRACK_ORIGSRC)
@@ -226,6 +263,9 @@ conntrack_mt(const struct sk_buff *skb, const struct net_device *in, 
		    !(info->invert_flags & XT_CONNTRACK_REPLDST))

			return false;



	if (!ct_proto_port_check(info, ct))

		return false;



	if ((info->match_flags & XT_CONNTRACK_STATUS) &&

	    (!!(info->status_mask & ct->status) ^

	    !(info->invert_flags & XT_CONNTRACK_STATUS)))