--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/linklayerprotocols/pppnif/INC/PPPLRD.H	Tue Jan 26 15:23:49 2010 +0200
@@ -0,0 +1,94 @@
+// 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