// Copyright (c) 1997-2009 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

 @internalComponent 

*/

#if !defined(__PPPLRD_H__)

#define __PPPLRD_H__

#include <nifutl.h>

//SPECS//

// The specs I got for LRD are:

// · LCP echo/reply packet are used to ensure the link quality.

// The link will be closed if 4 out of 5 echo reply pairs fail 

// i.e. server does not answer. LCP echo packet is sent after 

// every 10 seconds.

// So we just create a timer with a 10 secs period.

// On every tick 

// - Check it got an answer to the previous echo

// - If the link is open send another echo. 

//

// lrd functionnality can be tweaked through ppp.ini

// entries are:

// [lrd]

// PPPEnableLRD = 0:disabled/1:enabled

// PPPLRDPeriod = (a value between min period and max period)

_LIT(LRDSECTIONNAME,"lrd");

_LIT(LRDENTRYNAME_ENABLE,"PPPEnableLRD");

const TInt KPppLrdDefaultEnabledMode = 0;

_LIT(LRDENTRYNAME_PERIOD,"PPPLRDPeriod");

const TInt KPppLrdTimerPriority = 10;

const TInt KPppLrdDefaultTimerPeriod = 10; // 10 secs by default

const TInt KPppLrdTimerPeriodMax = 60; // 60 secs 

// Why would anybody want more than 60?

const TInt KPppLrdTimerPeriodMin = 03; // really small period 

// stops the ppp stack from working

// Nile spec says:

// Fails if 4 out of 5 (most recent) tries fail

// the way we detect that is by keeping track of our tries

// in a shift register associated with a counter 

// which keeps track of the number of bits in it.

// On each period, shift the register left (update bit counter)

// set the rightmost bit if we got an echo reply (update bit counter)

// Check the bit counter and see it has not dropped below KMaxNFailure

const TUint KSampleWidth = 5;

const TUint	KMaxNFailure = 4;

const TUint KShiftRegisterWidth = (1<<KSampleWidth)-1;

const TUint KBitOverflow = 1<<KSampleWidth;

class CPppLcp;

NONSHARABLE_CLASS(CPppLrd) : public MTimer 

	{

public:

	CPppLrd(CPppLcp*);

	virtual ~CPppLrd();

	static CPppLrd* NewL(CPppLcp*);

	void ConstructL();

	void StartTimer();

	void StopTimer();

	void ResetTimer();

	void RecvEchoReply(TUint8);

	void EnableOrDisableTimer(TBool aEnable);

private:

// MTimer upcall

	void TimerComplete(TInt aStatus);

	void ReadIniFileL();

	TBool	iPppLrdEnabled;

	TBool	iLastEchoAck;

	TUint8	iEchoReqFrameIdentifier;

	TInt	iLrdPeriod;

	TUint	iBitCount;

	TUint	iShiftRegister;

	CPppLcp*	iPppLcp;

	};

#endif