// Copyright (c) 2006-2009 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:

// tcp.h - TCP protocol for IPv6/IPv4

// TCP protocol class declarations for IPv6/IPv4.

//

/**

 @file tcp.h

 @internalComponent

*/

#ifndef __TCP_H__

#define __TCP_H__

#include "in_trans.h"

#include <ip6_hdr.h>

#include <tcp_hdr.h>

#include <in_chk.h>

#include "frag.h"

#include "inet6log.h"

#include <in6_opt.h>

#ifdef SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

#include <in_sock.h>

#endif //SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

// Define the following macro here. Do NOT use macro statement in mmp file to define this.

//	The macro will be used in source files to confirm the right modifed header file is used.

//	Using macro statement in mmp file disables the trick.

//#define FJ_USE_VARIANT_TIMER

#ifdef FJ_USE_VARIANT_TIMER

#include <FjVariantTimer.h>

#endif

//

// Constants affecting protocol performance

//

const TUint KOneSecondUs      = 1000000;    //< Help for converting longer times to microseconds

const TUint KTcpMaximumWindow = 0x3fffffff;  //< Maximum receive window size

const TUint KTcpMinimumWindow =      1024;  //< Minimum receive window size

const TUint KTcpDefaultRcvWnd = 48 * 1024;  //< Default receive window size

const TUint KTcpDefaultSndWnd = 16 * 1024;  //< Default send window size

const TUint KTcpDefaultMSS    =     65535;  //< By default, MSS is not limited by user

const TUint KTcpStandardMSS   =       536;  //< Internet standard MSS

const TUint KTcpMinimumMSS    =        64;  //< Minimum acceptable MSS.

const TUint KTcpMaxTransmit   =         2;  //< Transmit at most this many segments at one time.

const TUint KTcpMinRTO        =   1000000;  //< us (1s)

const TUint KTcpMaxRTO        =  60000000;  //< us (60s)

const TUint KTcpInitialRTO    =   3000000;  //< us (3s)

const TUint KTcpSrttSmooth    =         8;  //< alpha = 1/8

const TUint KTcpMdevSmooth    =         4;  //< beta  = 1/4

const TUint KTcpRTO_K         =         4;  //< RTO = SRTT = 4 * RTTVAR

const TUint KTcpAckDelay      =    200000;  //< us (200ms)

const TUint KTcpMsl2Delay     =  60000000;  //< us (2x30s)

const TUint KTcpSynRetries    = 5;          //< Maximum retransmit attempts during connect.

const TUint KTcpMaxRetries1   = 3;          //< Maximum retransmit attempts before MTU reduction.

const TUint KTcpMaxRetries2   = 12;	    //< Maximum retransmit attempts during transmission.

const TUint KTcpReordering    = 3;          //< Worst case packet reordering in network.

const TUint KTcpInitialCwnd   = 2;          //< Initial congestion window

const TUint KTcpLtxWindow     = 2;          //< Limited transmit window (2 segments)

const TUint KTcpNumKeepAlives = 8;	    //< Number of keepalive probes before quitting.

const TUint KTcpKeepAliveRxmt = 75;	    //< Interval for retransmitted keepalives (seconds).

const TUint KTcpKeepAliveIntv = 2 * 3600;   //< Default interval between keepalives (seconds => 2 h).

const TUint KTcpKeepAliveTH   = 30;		//< Minimum time between triggered KeepAlives (seconds)

const TInt KTcpFinPersistency = 3;		//< Default for tcp_fin_persistency.

const TInt KTcpMaxLingerTime = 1800;	//< Max Linger Timeout in seconds (= 30 min).

#ifdef SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

const TUint KTcpDefaultRcvMaxWnd = 0x40000; // TCP Receive Max window = 262144

#endif //SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

//

// Maximum number of remembered urgent pointers. If the number of

// separate pending urgent bytes exceeds this number the urgent

// data bytes will start appearing in the received data (as if

// inlined).

//

// Discussion: We use a fairly light-weight method of removing

// out-of-band data from the data stream that involves no extra

// copying. BSD does it the hard way but still sometimes leaves

// droppings in the data stream. So, why bother? Increasing the

// number below reduces the probability of an out-of-band character

// appearing in the data stream. The cost is 4*n bytes state

// variable space. -ML

//

const TInt KTcpUpMax         = 5;

typedef TInet6Checksum<TInet6HeaderTCP> TTcpPacket;

/**

 * TCP timer

 */

#ifdef FJ_USE_VARIANT_TIMER

class CTcpTimer : public DCM::CVariantTimer

#else

class CTcpTimer : public CTimer

#endif

	{

public:

#ifdef FJ_USE_VARIANT_TIMER

	CTcpTimer(TCallBack& aCallBack, TInt aPriority = KInet6DefaultPriority)

    : DCM::CVariantTimer(aPriority), iCallBack(aCallBack.iFunction, aCallBack.iPtr)

#else

  CTcpTimer(TCallBack& aCallBack, TInt aPriority = KInet6DefaultPriority)

		: CTimer(aPriority), iCallBack(aCallBack.iFunction, aCallBack.iPtr)

#endif

		{ CActiveScheduler::Add(this); }

	virtual void RunL() { iCallBack.CallBack(); }

	virtual void InitL() { ConstructL(); }

	void Start(TUint aMicroSeconds)

		{

		if (!IsActive())

			After(aMicroSeconds);

		}

	void Restart(TUint aMicroSeconds)

		{

		if (IsActive())

			Cancel();

		After(aMicroSeconds);

		}

	private:

		TCallBack iCallBack;

	};

/**

 * TCP reassembly queue

 */

class RMBufTcpFrag : public RMBufFrag

	{

public:

	TUint Offset();

	TUint FragmentLength();

	void Join(RMBufChain& aChain);

	};

typedef RMBufFragQ<RMBufTcpFrag> RMBufTcpFragQ;

/**

 * TCP Protocol

 */

class CProtocolTCP6 : public CProtocolInet6Transport

	{

public:

	CProtocolTCP6();

	CProtocolTCP6& operator=(const CProtocolTCP6&);

	virtual ~CProtocolTCP6();

	virtual CServProviderBase *NewSAPL(TUint aProtocol);

	virtual void InitL(TDesC& aTag);

	virtual void StartL();

	virtual void Identify(TServerProtocolDesc *) const;

	//virtual TInt GetOption(TUint level,TUint name,TDes8 &option,CProtocolBase* aSourceProtocol=NULL);

	//virtual TInt SetOption(TUint level, TUint aName,const TDesC8 &option,CProtocolBase* aSourceProtocol=NULL);

	virtual TInt Send(RMBufChain& aPDU,CProtocolBase* aSourceProtocol=NULL);

	virtual void Process(RMBufChain& aPacket, CProtocolBase *aSourceProtocol = NULL);

	static void Describe(TServerProtocolDesc&);

	TUint32 RandomSequence();

	TInt SendControlSegment(RFlowContext *aFlow,

		const TSockAddr& aSrcAddr, const TSockAddr& aDstAddr,

		TUint8 aFlags, TTcpSeqNum aSeq, TTcpSeqNum aAck,

		TUint32 aWnd = 0, TUint32 aUP = 0);

	//

	// TCP Configuration Parameters

	//

	TUint MSS() const               { return iMSS; }

	TUint RecvBuf() const           { return iRecvBuf; }

	TUint SendBuf() const           { return iSendBuf; }

	TUint MinRTO() const            { return iMinRTO; }

	TUint MaxRTO() const            { return iMaxRTO; }

	TUint InitialRTO() const        { return iInitialRTO; }

	TUint SrttSmooth() const        { return iSrttSmooth; }

	TUint MdevSmooth() const        { return iMdevSmooth; }

	TUint RTO_K() const             { return iRTO_K; }

	TUint RTO_G() const             { return iRTO_G; }

	TUint ClockGranularity() const  { return iClockGranularity; }

	TUint AckDelay() const          { return iAckDelay; }

	TUint Msl2Delay() const         { return iMsl2Delay; }

	TUint SynRetries() const        { return iSynRetries; }

	TUint Retries1() const          { return iRetries1; }

	TUint Retries2() const          { return iRetries2; }

	TUint ProbeStyle() const        { return iProbeStyle; }

	TUint InitialCwnd() const       { return iInitialCwnd; }

	TUint LtxWindow() const         { return iLtxWindow; }

	TUint RFC2414() const           { return iRFC2414; }

	TUint Reordering() const        { return iReordering; }

	TUint MaxBurst() const          { return iMaxBurst; }

	TUint TimeStamps() const        { return iTimeStamps; }

	TUint Sack() const              { return iSack; }

	TUint LocalTimeWait() const     { return iLocalTimeWait; }

	TUint StrictNagle() const       { return iStrictNagle; }

	TUint PushAck() const           { return iPushAck; }

	TUint FRTO() const				{ return iFRTO; }

	TUint DSack() const				{ return iSack && iDSack; }

	TUint KeepAliveIntv() const		{ return iKeepAliveIntv; }

	TUint KeepAliveRxmt() const		{ return iKeepAliveRxmt; }

	TUint NumKeepAlives() const		{ return iNumKeepAlives; }

	TUint DstCache() const			{ return iDstCache; }

	TUint Ecn() const				{ return iEcn; }

	TUint FinPersistency() const	{ return iFinPersistency; }

	TUint SpuriousRtoResponse() const { return iSpuriousRtoResponse; }

	TInt WinScale()					{ return iWinScale; }

	TInt AlignOpt() const 			{ return iAlignOpt; }

#ifdef SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

	//Function to set and get receive window

	void SetRecvWin(TUint aRecvWin) { iRecvBuf = aRecvWin;}

	TUint GetRecvWinSize()			{ return iRecvBuf;	 }

	TUint RecvMaxWnd()              { return iTcpMaxRecvWin;}

#endif //SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

#ifdef _LOG

	static void LogPacket(char aDir, RMBufChain& aPacket, RMBufPktInfo *info = 0, TInt aOffset = 0);

#endif

private:

	TUint	iMSS;

	TUint   iRecvBuf;

	TUint   iSendBuf;

	TUint   iMinRTO;

	TUint   iMaxRTO;

	TUint   iInitialRTO;

	TUint   iSrttSmooth;

	TUint   iMdevSmooth;

	TUint   iRTO_G;

	TUint   iRTO_K;

	TUint   iMaxBurst;

	TUint   iAckDelay;

	TUint   iSynRetries;

	TUint   iRetries1;

	TUint   iRetries2;

	TUint   iProbeStyle;

	TUint   iClockGranularity;

	TUint   iMsl2Delay;

	TUint   iInitialCwnd;

	TUint   iLtxWindow;

	TUint   iReordering;

	TUint	iKeepAliveIntv;

	TUint	iKeepAliveRxmt;

	TUint	iNumKeepAlives;

	TUint	iFinPersistency;

	TInt8   iWinScale;		//< value of "tcp_winscale" option: -1 ... 7

	// Flags

	TUint  	iTimeStamps:1;

	TUint  	iSack:1;

	TUint  	iLocalTimeWait:1;

	TUint  	iStrictNagle:1;

	TUint  	iRFC2414:1;

	TUint 	iPushAck:1;

	TUint 	iFRTO:1;

	TUint 	iDSack:1;

	TUint  	iDstCache:1;

	TUint	iAlignOpt:1;	//< Set if TCP options should be aligned using NOP option.

	// Ecn has 3 reasonable settings: 0 = disable, 1 = enable with ECT(1), 2 = enable with ECT(0).

	// Old specification used only ECT(0), so there may be routers out there that only understand

	// ECT(0) but not ECT(1).

	TUint	iEcn:2;

	// 8 possible values should be enough for spurious response alternatives.

	TUint	iSpuriousRtoResponse:3;

	TUint32 iRandomIncrement;

	RMBufAllocator iBufAllocator;

#ifdef SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

	TUint iTcpMaxRecvWin;

#endif //SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

	};

/**

 * TCP Socket Provider.

	*/

class CProviderTCP6 : public CProviderInet6Transport

	{

	friend class CProtocolTCP6;

public:

	CProviderTCP6(CProtocolInet6Base* aProtocol);

	virtual ~CProviderTCP6();

	virtual void InitL();

	virtual void Start();

	virtual TInt GetOption(TUint level,TUint name,TDes8 &anOption) const;

	virtual void Ioctl(TUint level,TUint name,TDes8* anOption);

	virtual void CancelIoctl(TUint aLevel, TUint aName);

	virtual TInt SetOption(TUint level,TUint name, const TDesC8 &anOption);

	virtual TInt SetRemName(TSockAddr &aAddr);

	virtual void Shutdown(TCloseType option);

	virtual void ActiveOpen();

	virtual TInt PassiveOpen(TUint aQueSize);

	virtual void ErrorExpire(TInt aError);

	virtual void CanSend();

	// PRTv1.0 send and receive methods

	virtual TUint Write(const TDesC8 &aDesc,TUint options, TSockAddr* aAddr=NULL);

	virtual void GetData(TDes8 &aDesc,TUint options,TSockAddr *aAddr=NULL);

	// PRTv1.5 send and receive methods

	virtual TInt Write(RMBufChain& aData, TUint aOptions, TSockAddr* anAddr=NULL);

	virtual TInt GetData(RMBufChain& aData, TUint aLength, TUint aOptions, TSockAddr* anAddr=NULL);

	// Parent socket methods

	TInt CreateChild(CProviderTCP6*& aSAP);

	void DetachChild(CProviderTCP6* aSAP);

	TInt CompleteChildConnect(CProviderTCP6* aSAP);

	inline void SetChildDeleted(TBool aDeleted);

	virtual void Process(RMBufChain& aPacket, CProtocolBase *aSourceProtocol = NULL);

	CProtocolTCP6* Protocol() const { return (CProtocolTCP6*)iProtocol; }

	virtual void IcmpError(TInt aError, TUint aOperationMask, TInt aType, TInt aCode,

		const TInetAddr& aSrcAddr, const TInetAddr& aDstAddr, const TInetAddr& aErrAddr);

	inline void LingerTimeout();

	virtual TInt CheckPolicy(const TSecurityPolicy& aPolicy, const char *aDiagnostic);

private:

    RMBufAllocator iBufAllocator;

	// Connection state

	enum TTcpStateEnum

		{

		ETcpInitial      = 0x0001,

		ETcpListen       = 0x0002,

		ETcpSynSent      = 0x0004,

		ETcpSynReceived  = 0x0008,

		ETcpEstablished  = 0x0010,

		ETcpFinWait1     = 0x0020,

		ETcpFinWait2     = 0x0040,

		ETcpCloseWait    = 0x0080,

		ETcpClosing      = 0x0100,

		ETcpLastAck      = 0x0200,

		ETcpTimeWait     = 0x0400,

		ETcpClosed       = 0x0800,

		ETcpConnect      = 0x1000

		} iState;

	//

	//.    Send Window Management

	//

	//      SND.UNA - send unacknowledged

	//      SND.NXT - send next

	//      SND.WND - send window

	//      SND.UP  - send urgent pointer

	//      SND.WL1 - segment sequence number used for last window update

	//      SND.WL2 - segment acknowledgment number used for last window update

	//      ISS     - initial send sequence number

	//

	struct TTcpSendSequence

		{

		TTcpSeqNum UNA;

		TTcpSeqNum NXT;

		TTcpSeqNum WL1;

		TTcpSeqNum WL2;

		TTcpSeqNum UP;

		TUint32    WND;

		} iSND;

	//

	//    Receive Window Management

	//

	//      RCV.NXT - receive next

	//      RCV.WND - receive window

	//      RCV.UP  - receive urgent pointer

	//      IRS     - initial receive sequence number

	//

	struct TTcpRecvSequence

		{

		TTcpSeqNum NXT;

		//TTcpSeqNum UP;

		TUint32    WND;

		} iRCV;

	TTcpSeqNum        iFinSeq;

	// Window updates

	TUint32           iFreeWindow;

	TUint32           iAdvertisedWindow;

	// Retransmission control

	TTcpSeqNum	    iLastAck;

	TTcpSeqNum	    iTransmitSeq;

	TTcpSeqNum	    iRecoverSeq;

	TTcpSeqNum	    iSendHigh;

	TUint		    iDupAcks;

	TUint		    iLastWnd;

	// Queue management

	RMBufAsyncPktQ	iSendQ;

	RMBufAsyncPktQ  iRecvQ;

	RMBufTcpFragQ	iFragQ;

	RMBufSockQ	    iSockOutQ;

	RMBufSockQ	    iSockInQ;

	TUint		    iSockOutQLen;

	TUint		    iSockInQLen;

	TUint		    iSockOutBufSize;

	TUint		    iSockInBufSize;

	TUint			iNewData;

	TUint           iPending;

#ifdef SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

	//Window size for startup case

	TUint32 iTcpMaxRecvWin;

    //New window set by the bearer in case of window shrink

	TUint32 iNewTcpWindow;

	//Size of buffer read by the application from the TCP receive buffer

	//but is not transparent while advertising a new TCP window to the sender.	

	TUint32 iHiddenFreeWindow;

	//  Size of Window Shrink

	TUint32 iShrinkedWindowSize;

	// Window size set by user. This will override the default values for the bearers

	TBool   iWindowSetByUser;

#endif //SYMBIAN_ADAPTIVE_TCP_RECEIVE_WINDOW

	// Maximum Segment Sizes

	TUint           iMSS;   //< Maximum set by user

	TUint		    iSMSS;  //< Send MSS

	TUint		    iRMSS;  //< Receive MSS

	// Asynchronous events

	CAsyncCallBack  *iTransmitter;

	CTcpTimer	    *iDelayAckTimer;

	CTcpTimer	    *iRetransTimer;

	CTcpTimer	    *iLingerTimer;

	// RTT timing

	TTime		    iStartTime;		  //< Time at the beginning of connection.

	TUint32	    	iTimeStamp;		  //< Last time stamp taken

	TTcpSeqNum	    iTimingSeq;

	TUint32	    	iTsRecent;

	// RTO calculation

	TUint32	    iRTO;

	TUint32	    iSRTT;

	TUint32	    iMDEV;

	TUint		iBackoff;

	// Delay spike detection

	TUint32     iLastTimeout;         //< Timestamp of last RTO

	// Keep-Alive triggering

	TUint32		iLastTriggeredKeepAlive; //< Last triggered keep-alive

	// Congestion control

	TUint32	    iCwnd;

	TUint32     iLwnd;

	TUint32	    iSsthresh;

	TTcpSeqNum  iQuenchSeq;           //< Store right window edge at source quench

	TTcpSeqNum	iPartialSeq;

	// TCP options

	TTcpOptions	iOptions;

	// Server socket state

	TUint		    iListenQueueSize;	  //< Listen queue size.

	TUint		    iConnectCount;	  //< Number active connect attempts;

	CProviderTCP6	*iParent;		  //< Parent socket

	CProviderTCP6   **iListenQueue;       //< Array holding pointers to child sockets

	TBool			iChildDeleted;		//< Flag for notifying parent that a child was deleted by SocketServer

	// Urgent data handling

	TTcpSeqNum        iUpArray[KTcpUpMax];

	TInt              iUpIndex;

	TInt              iUpCount;

	// Large peek offset

	TInt              iCopyOutOffset;

	// SACK book keeping

	SequenceBlockQueue  iSacked;

	// FACK book keeping

	TUint32           iRetranData;

	// Needed state information for F-RTO/DCLOR retransmission

	TUint32			iFRTOsent;  //< True, if rto was sent and no acks have yet arrived

	TTcpSeqNum		iRealSendHigh;  //< iSendHigh is not real with SACK

	// -1=linger disabled, >=0 linger enabled with given time in seconds.

	TInt			iLinger;

	// Window scaling factor for the send window, advertised by the other end.

	TUint8			iSndWscale:4;

	// Window scaling factor for receive window, based on ini settings.

	TUint8			iRcvWscale:4;

	TUint iRetryAck;  // to keep count of the ACKs that inform missing segments

	// Flags

	struct TTcpFlags

		{

		// Additional TCP state

		TUint32		iStarted:1;		  //< Protocol has been started

		TUint32	    iFastRetransMode:1;   //< We're in fast retransmit mode