Commit a0ca215a authored by Masahide NAKAMURA's avatar Masahide NAKAMURA Committed by David S. Miller
Browse files

[NETFILTER]: ip6_tables: support MH match 



This introduces match for Mobility Header (MH) described by Mobile IPv6
specification (RFC3775). User can specify the MH type or its range to be
matched.

Signed-off-by: default avatarMasahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: default avatarYasuyuki Kozakai <kozakai@linux-ipv6.org>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e60a13e0

include/linux/netfilter_ipv6/ip6t_mh.h

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#ifndef _IP6T_MH_H

#define _IP6T_MH_H



/* MH matching stuff */

struct ip6t_mh

{

	u_int8_t types[2];	/* MH type range */

	u_int8_t invflags;	/* Inverse flags */

};



/* Values for "invflags" field in struct ip6t_mh. */

#define IP6T_MH_INV_TYPE	0x01	/* Invert the sense of type. */

#define IP6T_MH_INV_MASK	0x01	/* All possible flags. */



#endif /*_IP6T_MH_H*/

net/ipv6/netfilter/Kconfig

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@@ -114,6 +114,14 @@ config IP6_NF_MATCH_AH 


	  To compile it as a module, choose M here.  If unsure, say N.



config IP6_NF_MATCH_MH

	tristate "MH match support"

	depends on IP6_NF_IPTABLES

	help

	  This module allows one to match MH packets.



	  To compile it as a module, choose M here.  If unsure, say N.



config IP6_NF_MATCH_EUI64

	tristate "EUI64 address check"

	depends on IP6_NF_IPTABLES

net/ipv6/netfilter/Makefile

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@@ -19,6 +19,7 @@ obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o 
obj-$(CONFIG_IP6_NF_RAW) += ip6table_raw.o

obj-$(CONFIG_IP6_NF_MATCH_HL) += ip6t_hl.o

obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o

obj-$(CONFIG_IP6_NF_MATCH_MH) += ip6t_mh.o



# objects for l3 independent conntrack

nf_conntrack_ipv6-objs  :=  nf_conntrack_l3proto_ipv6.o nf_conntrack_proto_icmpv6.o nf_conntrack_reasm.o

net/ipv6/netfilter/ip6t_mh.c

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/*

 * Copyright (C)2006 USAGI/WIDE Project

 *

 * 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.

 *

 * Author:

 *	Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>

 *

 * Based on net/netfilter/xt_tcpudp.c

 *

 */

#include <linux/types.h>

#include <linux/module.h>

#include <net/ip.h>

#include <linux/ipv6.h>

#include <net/ipv6.h>

#include <net/mip6.h>



#include <linux/netfilter/x_tables.h>

#include <linux/netfilter_ipv6/ip6t_mh.h>



MODULE_DESCRIPTION("ip6t_tables match for MH");

MODULE_LICENSE("GPL");



#ifdef DEBUG_IP_FIREWALL_USER

#define duprintf(format, args...) printk(format , ## args)

#else

#define duprintf(format, args...)

#endif



/* Returns 1 if the type is matched by the range, 0 otherwise */

static inline int

type_match(u_int8_t min, u_int8_t max, u_int8_t type, int invert)

{

	int ret;



	ret = (type >= min && type <= max) ^ invert;

	return ret;

}



static int

match(const struct sk_buff *skb,

	 const struct net_device *in,

	 const struct net_device *out,

	 const struct xt_match *match,

	 const void *matchinfo,

	 int offset,

	 unsigned int protoff,

	 int *hotdrop)

{

	struct ip6_mh _mh, *mh;

	const struct ip6t_mh *mhinfo = matchinfo;



	/* Must not be a fragment. */

	if (offset)

		return 0;



	mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);

	if (mh == NULL) {

		/* We've been asked to examine this packet, and we

		   can't.  Hence, no choice but to drop. */

		duprintf("Dropping evil MH tinygram.\n");

		*hotdrop = 1;

		return 0;

	}



	return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,

			  !!(mhinfo->invflags & IP6T_MH_INV_TYPE));

}



/* Called when user tries to insert an entry of this type. */

static int

mh_checkentry(const char *tablename,

	      const void *entry,

	      const struct xt_match *match,

	      void *matchinfo,

	      unsigned int hook_mask)

{

	const struct ip6t_mh *mhinfo = matchinfo;



	/* Must specify no unknown invflags */

	return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);

}



static struct xt_match mh_match = {

	.name		= "mh",

	.family		= AF_INET6,

	.checkentry	= mh_checkentry,

	.match		= match,

	.matchsize	= sizeof(struct ip6t_mh),

	.proto		= IPPROTO_MH,

	.me		= THIS_MODULE,

};



static int __init ip6t_mh_init(void)

{

	return xt_register_match(&mh_match);

}



static void __exit ip6t_mh_fini(void)

{

	xt_unregister_match(&mh_match);

}



module_init(ip6t_mh_init);

module_exit(ip6t_mh_fini);