//dnsproxyqryhandler.h

/*

* Copyright (c) 2008-2009 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

* @internalTechnology

*

*/

#ifndef DNS_PROXYQRYHANDLER_H

#define DNS_PROXYQRYHANDLER_H

#include <in_sock.h>

#include <timeout.h>

#include "dns_hdr.h"

//forward declaration

class CDnsProxyEngine;

class CDnsProxyListener;

class TQueryContext;

class CDnsServerConfig;

/*

 * This enum represents the state of query handler active object.

 * @internalTechnology

 * */ 

 enum TStatus

	{

	EInit,       // This is the initial state of an active object once sendto is called

	EComplete    // This is the response waiting state which means receive is pending

	};

class CDnsProxyQueryHandler:public CActive

	{

/*

 * This class sends global query to available uplinks at given time

 * receives response and sends the same back to the querying host using

 * local writer.

 * This class is derived from CActive

 * @internalTechnology

 * */

	public:

		//two phase construction

		static CDnsProxyQueryHandler* NewL(CDnsProxyEngine& aEngine, CDnsProxyListener& aListener);

		//destructor

		~CDnsProxyQueryHandler();

	public:

		//Invoked when request compltes

		void RunL();

		//Method to cancel outstanding request of the active object

		void DoCancel();

		//this will be invoked whenever RunL function leaves

		TInt RunError(TInt aErr);

		void BindRandomPort();

		void SendQuery(TInetAddr& aServerAddress);

		void ProcessQueryL();

		void SetQueryContext(TQueryContext* aQueryContext);

		void RunReader();

		void CancelTimer(); 

		TBool GetQHandlerState();

		void SetQHandlerState(TBool aQueryHandlerStatus);

		// A callback method when the timeout expires

		void TimeoutL(const TTime &aNow);

		// Request a call to Timeout after specified time (seconds)

		void SetTimer(TUint aTimeout);

	protected:

		//constructor

		CDnsProxyQueryHandler(CDnsProxyEngine& aEngine, CDnsProxyListener& aListener);

	private:

		// Process Any pending Query

		void ProcessNextQueryL();

		//Set the state of AO

		void SetActiveObjectState(TStatus aState);

		//Get the state of AO

		TStatus GetActiveObjectState();

		//Reset the Query Handler

		void QueryDone();

		//Reset server count

		void ResetServerCount();

		//Reset timeout count

		void ResetTimerCount();

		//Reset timeout count

		void ResetSockActiveStatus();

		//send DNS server failure to the host if the uplink is not available.

		void SendDnsFailureL();

		//Activate the socket

		void ActivateSocketL();

		//Deactivate the socket

		void DeActivateSocket();

	public:

		RTimeout iTimeout;	           // Timer

	private:	

		CDnsProxyEngine& iProxyEngine; // Instance of control class

		CDnsProxyListener& iListener;  // Instance of listener class

		RSocket iSocket;               // Outbound socket

		TBool iActiveStatus;           // Status of the socket 

		TBool iQueryHandlerStatus;     // Status of QueryHandler

		TInt iServerCount;             // Number of servers available

		TInt iCurServer;               // Current server in use

		TInt iTimerCount;              // This is current retry count

		TInt iRetryCount;              // This is maximum possible retries

		TQueryContext* iQueryContext;  // Current Query context under processing

		CDnsServerConfig* iProxyServer;// External DNS server configuration  

		TBuf8<KDnsMaxMessage> iReply;  // DNS reply 

		TSockAddr iFrom;               // Query Source

		TInetAddr iServerAddress;      // Current DNS server address

		TUint32 iCurrentUplink;        // Current Uplink in Use

		TStatus iSocketStatus;         // Active object state

	};

inline void CDnsProxyQueryHandler::ResetServerCount()

/**

 *  Reset server count

 *  @internalTechnology

 * */

	{ 

	iCurServer = 0; 

	}

inline void CDnsProxyQueryHandler::ResetTimerCount()

/**

 *  Reset timeout count

 *  @internalTechnology

 * */

	{

	iTimerCount = 0; 

	}

inline void CDnsProxyQueryHandler::ResetSockActiveStatus()

/**

 *  Reset socket active status

 *  @internalTechnology

 * */

	{ 

	iActiveStatus = EFalse; 

	}

#endif /*DNS_PROXYQRYHANDLER_H*/