// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

/**

 @file DHCPUnicastTranslator.cpp

 @internalComponent

*/

#include <in_chk.h>

#include <in_sock.h>

#include <in_bind.h>

#include "in6_opt.h"

#include <udp_hdr.h>

#include "DHCPUnicastTranslator.h"

#include "HookLog.h"

#include "ipeventlistener.h"

CDHCPUnicastTranslator::CDHCPUnicastTranslator(CProtocolInet6Binder& aParent):

	iParent(aParent)

	{

	}

CDHCPUnicastTranslator::~CDHCPUnicastTranslator()

	{

//	iParent.Unbind(this, 0);

	}

void CDHCPUnicastTranslator::FillIdentification(TServerProtocolDesc& anEntry)

/**

 * Fills in an existing protocol description structure with details of this protocol.

 *

 * @param aProtocolDesc: reference to the structure to be filled in

 */

	{

	anEntry.iName=_S("dhcpunicasttranslator");

	anEntry.iAddrFamily=KAfInet;

	anEntry.iSockType=0;

	anEntry.iProtocol=1; // not in a family so doesn't really matter

	anEntry.iVersion=TVersion(1, 0, 0);

	anEntry.iByteOrder=EBigEndian;

	anEntry.iServiceInfo=0;

	anEntry.iNamingServices=0;

	anEntry.iSecurity=0;

	anEntry.iMessageSize=0;

	anEntry.iServiceTypeInfo=0;

	anEntry.iNumSockets=0;

	}

void CDHCPUnicastTranslator::Identify(TServerProtocolDesc* aProtocolDesc) const

/**

 * Fills in an existing protocol description structure with details of this protocol.

 *

 * @param aProtocolDesc: pointer to the structure to be filled in

 */

	{

	FillIdentification(*aProtocolDesc);

	}

/**

 * Incoming packet

 */

TInt CDHCPUnicastTranslator::ApplyL(RMBufHookPacket& aPacket, RMBufRecvInfo& aInfo)

	{

	LOG	(

		_LIT(KHookNotifyStr,"CDHCPUnicastTranslator::ApplyL hit with protocol: %d");

		HookLog::Printf( KHookNotifyStr , aInfo.iProtocol );

		)

	/** Fix for INC079832 - DHCP must be able to receive unicast replies from

	 *   DHCP server (to an address that hasn't been set yet! chicken and egg).

	 *

	 *  Without this, a DHCP reply unicast to an address which isn't yet assigned

	 *   to the inbound interface will be dropped.

	 *

	 *  So we need to detect BOOTP packets which are about to be dropped. This is

	 *   done by installing this object as a "forwarding hook".

	 *

	 *  DHCP packets are detected as follows:

	 *   - packet is UDP

	 *   - UDP destination port is 0x0044

	 *

	 *  Modification is performed by setting dest address to broadcast address

	 *   (and updating checksum)

	 *

	 *  Then we return KIp6Hook_DONE (which signals to the stack to re-inject

	 *   the packet into the incoming data path).

	 *

	 *  Note: this trick isn't needed for IPv6 as link-local unicast is always

	 *   possible before network/global address has been assigned.

	 */

    if (aInfo.iVersion != 4 || aInfo.iProtocol != KProtocolInetUdp)

        return KIp6Hook_PASS;    // Only interested in IPv4 and UDP.

    TInetAddr&  dst = TInetAddr::Cast(aInfo.iDstAddr);

    if (!dst.IsUnicast())

        return KIp6Hook_PASS;    // Only the unicast case really needs fixing

    // Need to examine the UDP header

    TInet6Packet<TInet6HeaderUDP> udp(aPacket, aInfo.iOffset);

    if (udp.iHdr == NULL)

        return KIp6Hook_PASS;    // Oops, short packet, let someone else worry about it.

    // To cause least distruption, one could try to check that this really is

    // DCHP address configuration message with packet destination address

    // matching the offered address inside DCHP message (but this would need

    // more extensive packet snooping here)    

#ifndef _DEBUG

    if (udp.iHdr->DstPort() == 68)

#else

	if (udp.iHdr->DstPort() == 68 || udp.iHdr->DstPort() == 127 || udp.iHdr->DstPort() == 119 || udp.iHdr->DstPort() == 125

	#ifdef SYMBIAN_NETWORKING_DHCP_MSG_HEADERS

	|| udp.iHdr->DstPort() == 92 || udp.iHdr->DstPort() == 99

	#endif//SYMBIAN_NETWORKING_DHCP_MSG_HEADERS	

	)	// debug mode, src port 127, 119, 125, 91, 98

#endif

        {

        static const TIp6Addr broadcast = {{{0,0,0,0,0,0,0,0,0,0,0xff,0xff,255,255,255,255}}};

        dst.SetAddress(broadcast);

        udp.iHdr->SetChecksum(0);    // Either this or recompute the UDP checksum for broadcast address.

        return KIp6Hook_DONE;

        }

    return KIp6Hook_PASS;

	}