// PPPLRD.H
//
// Copyright (c) 1997-1999 Symbian Ltd.  All rights reserved.
//

#if !defined(__PPPLRD_H__)
#define __PPPLRD_H__

#if !defined(__E32BASE_H__)
#include <e32base.h>
#endif
#if !defined(__E32DEF_H__)
#include <e32def.h>
#endif
#include <es_prot.h>
#include <es_mbuf.h>

#include "pppsock.h"
#include "nifman.h"

#include "nifmbuf.h"
#include "nifutl.h"

#include "pppcomp.h"
#include "f32file.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");// Disable plain text authentication
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 CPppLrd : public MTimer 
	{
	public:
		CPppLrd(CPppLcp*);
		virtual ~CPppLrd();
		static CPppLrd* NewL(CPppLcp*);
		void ConstructL();
		void StartTimer();
		void StopTimer();
		void ResetTimer();
		void RecvEchoReply(TUint8);
	private:
	// MTimer upcall
	void TimerComplete(TInt aStatus);
	void ReadIniFileL();
	TBool	iPppLrdEnabled;
	TBool	iLastEchoAck;
	TUint8	iEchoReqFrameIdentifier;
	TInt	iLrdPeriod;
	TUint	iBitCount;
	TUint	iShiftRegister;
	CPppLcp*	iPppLcp;
	};
#endif