/*

* Copyright (c) 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: 

*

*/

#include "cdnspacket.h"

CDnsPacket::CDnsPacket(const TDes8& aPacketPtr): iPtr(aPacketPtr.Ptr()),iDataLength(aPacketPtr.Size()),

           iMaxLength(aPacketPtr.MaxSize())

	{	

	}

CDnsPacket* CDnsPacket::NewL(const TDes8& aPacketPtr)

	{

	CDnsPacket* self =  new (ELeave) CDnsPacket( aPacketPtr );	

	CleanupStack::PushL(self);

	self->ConstructL();

	CleanupStack::Pop(self);

	return self;

	}	

CDnsPacket::~CDnsPacket()

	{	

	}

void CDnsPacket::ConstructL()

	{

	iIndex = 0;

	}

TUint8 CDnsPacket::GetCharL()

	{

	__OOB(iIndex,iDataLength)

	TUint8 val = *(iPtr+iIndex);

	iIndex += sizeof(TUint8);		

	return val;

	}

TUint16 CDnsPacket::GetInt16L()

	{

	__OOB(iIndex,iDataLength)

	TUint16 val = BigEndian::Get16(iPtr+iIndex);

	iIndex += sizeof(TUint16);		

	return val;

	}

TUint32 CDnsPacket::GetInt32L()

	{

	__OOB(iIndex,iDataLength)

	TUint32 val = BigEndian::Get32(iPtr+iIndex);

	iIndex += sizeof(TUint32);		

	return val;

	}

const TDnsHeader& CDnsPacket::GetHeaderL()

	{

	iHeader.SetId(GetInt16L());

	iHeader.SetFlags(GetInt16L());

	iHeader.SetQueryCount(GetInt16L());

	iHeader.SetAnswerCount(GetInt16L());

	iHeader.SetAuthorityNSCount(GetInt16L());

	iHeader.SetAdditionalRCount(GetInt16L());

	return iHeader;

	}

void CDnsPacket::GetDomainNameL(TDes8& aName)

	{	

	TInt labelLen = GetCharL();

	RBuf8 label;

	TInt isStartingWithPointer = labelLen & KPointerBit;

	if(isStartingWithPointer)

	    {

		TUint16 pointerOffset = labelLen & KPointerOffsetBit;

		__OOB(pointerOffset,iDataLength)

		pointerOffset = (pointerOffset << 8) + GetCharL();

		GetDomainNameAtIndexL(aName, pointerOffset);			

	    }

	else

		{

		while(labelLen)

			{			

			TInt isPointer = labelLen & KPointerBit;			

			if(isPointer)

				{

				TUint16 pointerOffset = labelLen & KPointerOffsetBit;

				__OOB(pointerOffset,iDataLength)

				pointerOffset = (pointerOffset << 8) + GetCharL();

				label.CreateL(KMaxDNSNameLength);

				GetStringAtIndexL(label,pointerOffset);		

				}

			else

				{

				label.CreateL(labelLen);

				GetStringL(label,labelLen);

				}			

			aName.Append(label);

            if(aName[aName.Size()-1]!='.')

                aName.Append(KDot);

			label.Close();

			if(isPointer )

				{

				break;

				}

			else

				{

				labelLen = GetCharL();		

				}			

			}

		}		

	}

void CDnsPacket::GetRdDomainNameL(TDes8& aDomainName,TUint aLength)

	{	

	TInt labelLen = GetCharL();

	aLength--;

	RBuf8 label;

	TInt isStartingWithPointer = labelLen & KPointerBit;

	while(aLength)

		{		

		TInt isPointer = labelLen & KPointerBit;	

		if(isPointer)

			{

			TUint16 pointerOffset = labelLen & KPointerOffsetBit;

			__OOB(pointerOffset,iDataLength)

			pointerOffset = (pointerOffset << 8) + GetCharL();

			aLength--;

			label.CreateL(KMaxLabelLength);

			if(isStartingWithPointer )  

				{

				GetDomainNameAtIndexL(aDomainName, pointerOffset);

				}

			else

				{

				GetDomainNameAtIndexL(label, pointerOffset);

				//GetStringAtIndexL(label, pointerOffset);				

				}

			}

		else

			{

			label.CreateL(labelLen);

			GetStringL(label,labelLen);

			aLength-=labelLen;

			}

		aDomainName.Append(label);

		label.Close();

		if(isStartingWithPointer)

			{

			break;

			}

		else

			{

			if(aLength )

				{

				labelLen = GetCharL();

				aLength--;

                if(aDomainName[aDomainName.Size()-1]!='.')

                    aDomainName.Append(KDot);

				}

			}

		}

	}

void CDnsPacket::GetStringL(TDes8& aString, TUint16 aLength)	

	{

	__OOB(iIndex,iDataLength)

	aString.Copy(iPtr+iIndex,aLength);

	iIndex+= aLength;

	}

void CDnsPacket::GetDomainNameAtIndexL(TDes8& aDomainName, TUint aOffset)

	{

	__OOB(aOffset,iDataLength)

	TUint8 labelLen = *(iPtr + aOffset);

	RBuf8 label;

	TInt isPointer;

	TUint16 pointerOffset;

	TInt isStartingWithPointer = labelLen & KPointerBit;

	TUint8 ptrPos;

	if(isStartingWithPointer)

		{

		pointerOffset = labelLen & KPointerOffsetBit;

		__OOB(aOffset,iDataLength)

		aOffset++;

		ptrPos = *(iPtr + aOffset);

		pointerOffset = (pointerOffset << 8) + ptrPos;		

		GetDomainNameAtIndexL(aDomainName, pointerOffset);

		}

	else

		{

		while(labelLen)		

			{

			label.CreateL(KMaxLabelLength);

			GetStringAtIndexL(label, aOffset);

			aDomainName.Append(label);

            if(aDomainName[aDomainName.Size()-1]!='.')

                aDomainName.Append(KDot);

			__OOB(aOffset,iDataLength)

			aOffset++; // increment by one byte for length field

			aOffset += labelLen;

			label.Close();	

			labelLen = 	*(iPtr + aOffset);

			isPointer = labelLen & KPointerBit;

			if(isPointer)

				{

				pointerOffset = labelLen & KPointerOffsetBit;

				__OOB(aOffset,iDataLength)

				aOffset++;

				ptrPos = *(iPtr + aOffset);

				pointerOffset = (pointerOffset << 8) + ptrPos;			

				label.CreateL(KMaxLabelLength);

				GetStringAtIndexL(label, pointerOffset);				

				aDomainName.Append(label);

				if(aDomainName[aDomainName.Size()-1]!='.')

				    aDomainName.Append(KDot);

				label.Close();

				break;

				}

			}

		}	

	}

void CDnsPacket::GetStringAtIndexL(TDes8& aLabel, TUint aOffset)

	{

	__OOB(aOffset,iDataLength)

	TUint8 labelLen = *(iPtr + aOffset);

	if(labelLen & KPointerBit)		// recursive pointers

		{

		TUint16 pointerOffset = labelLen & KPointerOffsetBit;

		pointerOffset = (pointerOffset << 8) + GetCharL();

		GetStringAtIndexL(aLabel, pointerOffset);

		}

	else

		{

		aLabel.Copy(iPtr+aOffset+1, labelLen);			

		}

	}