// Copyright (c) 2004-2009 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_hdr.h - TCP protocol header structure

// Defines the basic classes for accessing the header structures within TCP packets.

//

/**

 @file tcp_hdr.h 

 @ingroup ip_packet_formats

 @publishedAll

 @released

*/

#ifndef __TCP_HDR_H__

#define __TCP_HDR_H__

#include <e32std.h>

#include "in_hdr.h"

#include "sbque.h"

/**

* @addtogroup ip_packet_formats

* @{

*/

//

// TInet6HeaderTCP

//

//	*NOTE*

//		TInet6HeaderTCP declares for maximum length TCP header

//		(64	bytes). A valid TCP packet can be shorter and failing

//		to map full 64 bytes from a packet is not an error condition.

//

/** @name TCP Header length constants

* @{

*/

const TInt KTcpMinHeaderLength = 20;

const TInt KTcpMaxHeaderLength = 60;

const TInt KTcpMaxOptionLength = 40;

/** @} */

/** @name TCP control flags

* @{

*/

const TUint8 KTcpCtlFIN = 1;

const TUint8 KTcpCtlSYN = 2;

const TUint8 KTcpCtlRST = 4;

const TUint8 KTcpCtlPSH = 8;

const TUint8 KTcpCtlACK = 16;

const TUint8 KTcpCtlURG = 32;

const TUint8 KTcpCtlECE = 0x40;

const TUint8 KTcpCtlCWR = 0x80;

/** @} */

/** @name TCP options

* @{

*/

const TUint8 KTcpOptEnd		=  0;

const TUint8 KTcpOptNop		=  1;

const TUint8 KTcpOptMSS		=  2;

const TUint8 KTcpOptWScale	=  3;

const TUint8 KTcpOptSackOk	=  4;

const TUint8 KTcpOptSack	=  5;

const TUint8 KTcpOptTimeStamps  =  8;

const TUint8 KTcpOptCount	=  9;

const TUint8 KTcpOptMinLen[] =  {1,  1,  4,  3,  2,  6,  2,  2, 10};

const TUint8 KTcpOptMaxLen[] =  {1,  1,  4,  3,  2, 36, 40, 40, 10};

const TUint32 KTcpOptAlignFlag = 0x00000001;

/** @} */

class TTcpOptions

/** TCP Options Header.

@publishedAll

@released

*/

	{

public:

  	inline TTcpOptions()			      { Init(); }

  	IMPORT_C void Init();

  	IMPORT_C TInt Length() const;

  	inline TBool Error() const		  { return iError; }

  	inline void ClearError()		      { iError = EFalse; }

  	inline TInt MSS() const		      { return iMSS; }

  	inline void SetMSS(TInt aMSS)		  { iMSS = aMSS; }

  	inline void ClearMSS()		      { iMSS = -1; }

  	inline TBool TimeStamps() const	  { return iTimeStamps; }

  	inline TBool TimeStamps(TUint32& aTsVal, TUint32& aTsEcr) const

    	{

      	aTsVal = iTsVal;

      	aTsEcr = iTsEcr;

      	return iTimeStamps;

    	}

  	inline void SetTimeStamps(TUint32 aTsVal, TUint32 aTsEcr)

    	{

      	iTsVal = aTsVal;

      	iTsEcr = aTsEcr;

      	iTimeStamps = ETrue;

    	}

  	inline void ClearTimeStamps()		  { iTimeStamps = EFalse; }

  	inline TBool SackOk() const		  { return iSackOk; }

  	inline void SetSackOk()		      { iSackOk = ETrue; }

  	inline void ClearSackOk()		      { iSackOk = EFalse; }

  	inline void SuppressSack(TBool aBool=ETrue) { iSuppressSack = aBool; }

  	inline SequenceBlockQueue& SackBlocks()     { return iBlocks; }

  	inline TInt Unknown() const		  { return iUnknown; }

  	inline void ClearUnknown()		  { iUnknown = 0; }

  	// Query window scale option from TCP header options.

  	// Wscale == 1 means scale factor 1, i.e. shift count of 0 is used in TCP option.

  	// Wscale == 0 means that wscale option is not used in TCP header.

  	inline TUint WindowScale() const		{ return iWscale; }

  	inline void SetWindowScale(TUint8 aWscale)	{ iWscale = aWscale; }

  	/**

  	If set, each option will be aligned to 32-bit longword boundaries with Nop padding.

  	By default the Nop padding is not applied.

  	@param aAlignNop	ETrue if option alignment should be applied. 

	*/

  	inline void SetAlignOpt(TBool aAlignOpt) 

  		{ 

  		if(aAlignOpt) 

  			iFlags |= KTcpOptAlignFlag; 

  		else 

  			iFlags &= ~KTcpOptAlignFlag;

  		}

private:

  	friend class TInet6HeaderTCP;

  	IMPORT_C TBool ProcessOptions(const TUint8 *aPtr, TUint aLen);

  	IMPORT_C TUint OutputOptions(TUint8 *aPtr, TUint aMaxLen);

  	void CheckOptAlignment(TUint8* aPtr, TUint& aI, TUint aNumBytes);

  	inline TInt AlignedLength(TInt aLength) const

  	/**

  	Calculate the actual space requirement for option with given length.

  	Takes optional 32-bit alignment into account.

  	*/

  		{ if (iFlags & KTcpOptAlignFlag) return (aLength + 3) & ~3; else return aLength; }

  	TInt	              iMSS;

  	TInt	              iUnknown;

  	TUint32             iTsVal;

  	TUint32             iTsEcr;

  	SequenceBlockQueue  iBlocks;

  	TBool	              iError;

  	TBool	              iTimeStamps;

  	TBool	              iSackOk;

  	TBool               iSuppressSack;

  	TUint				iWscale;	//< Window scale option [RFC 1323].

  	TUint32				iFlags;	//< ETrue if options are to be aligned.

	};

class TInet6HeaderTCP

/**  TCP segment header.

@verbatim

Extract from RFC-793

    0                   1                   2                   3

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |          Source Port          |       Destination Port        |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                        Sequence Number                        |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                    Acknowledgment Number                      |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |  Data |           |U|A|P|R|S|F|                               |

   | Offset| Reserved  |R|C|S|S|Y|I|            Window             |

   |       |           |G|K|H|T|N|N|                               |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |           Checksum            |         Urgent Pointer        |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                    Options                    |    Padding    |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                             data                              |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

@endverbatim

@publishedAll

@released

*/

	{

public:

	//

	// Basic

	//

	inline static TInt MinHeaderLength() {return KTcpMinHeaderLength; }

	inline static TInt MaxHeaderLength() {return KTcpMaxHeaderLength; }

	inline TUint8 *EndPtr() {return i + HeaderLength();}

	//

	// Access, Get TCP field values from the packet

	//

	inline TUint SrcPort() const

		{

		return (i[0] << 8) + i[1];

		}

	inline TUint DstPort() const

		{

		return (i[2] << 8) + i[3];

		}

	inline TTcpSeqNum Sequence() const

		{

		return (i[4] << 24) | (i[5] << 16) | (i[6] << 8) | i[7];

		}

	inline TTcpSeqNum Acknowledgment() const

		{

		return (i[8] << 24) | (i[9] << 16) | (i[10] << 8) | i[11];

		}

	inline TInt HeaderLength() const

		{

		// Return TCP Header Length in bytes (including options and padding)

		return (i[12] >> 2) & (0xF << 2);

		}

	//

	// A testing method for each individual Control Bit is provided

	// (It remains to be seen whether this is useful or not). Note

	// also that the result of the AND is returned, not 0 and 1.

	//

	inline TInt FIN() const

		{

		return i[13] & KTcpCtlFIN;

		}

	inline TInt SYN() const

		{

		return i[13] & KTcpCtlSYN;

		}

	inline TInt RST() const

		{

		return i[13] & KTcpCtlRST;

		}

	inline TInt PSH() const

		{

		return i[13] & KTcpCtlPSH;

		}

	inline TInt ACK() const

		{

		return i[13] & KTcpCtlACK;

		}

	inline TInt URG() const

		{

		return i[13] & KTcpCtlURG;

		}

	// ECN Echo flag [RFC 3168].

	inline TInt ECE() const

		{

		return i[13] & KTcpCtlECE;

		}

	// ECN: Congestion Window Reduced [RFC 3168].

	inline TInt CWR() const

		{

		return i[13] & KTcpCtlCWR;

		}	

	// A method to access all of the above as is. Note that this

	// also returns the reserved unspecified bits. Value can be

	// non-zero, even if none of the above is set. However, it only

	// returns unspecified bits from the 13th byte, not any from 12th!

	inline TUint8 Control() const

		{

		return i[13];

		}

	//

	inline TUint Window() const

		{

		return (i[14] << 8) + i[15];

		}

	inline TUint Checksum() const

		{

		// Checksum is used in network byte order

		return *((TUint16 *)&i[16]);

		}

	inline TUint Urgent() const

		{

		return (i[18] << 8) + i[19];

		}

	inline TBool Options(TTcpOptions& aOptions) const

		{

		return aOptions.ProcessOptions(i + KTcpMinHeaderLength, HeaderLength() - KTcpMinHeaderLength);

		}

	//Backwards compatibility, mainly for IPRotor.

	inline TPtr8 Options() const

		{

		TInt len = HeaderLength() - 20;

		return TPtr8((TUint8 *)&i[20], len, len);

		}

	//

	// Build, Set TCP field value to the packet

	//

	inline void SetSrcPort(TUint aPort)

		{

		i[0] = (TUint8)(aPort >> 8);

		i[1] = (TUint8)aPort;

		}

	inline void SetDstPort(TUint aPort)

		{

		i[2] = (TUint8)(aPort >> 8);

		i[3] = (TUint8)aPort;

		}

	inline void SetSequence(TTcpSeqNum aSeq)

		{

		i[7] = (TUint8)aSeq.Uint32();

		i[6] = (TUint8)(aSeq.Uint32() >> 8);

		i[5] = (TUint8)(aSeq.Uint32() >> 16);

		i[4] = (TUint8)(aSeq.Uint32() >> 24);

		}

	inline void SetAcknowledgment(TTcpSeqNum aAck)

		{

		i[11] = (TUint8)aAck.Uint32();

		i[10] = (TUint8)(aAck.Uint32() >> 8);

		i[9] = (TUint8)(aAck.Uint32() >> 16);

		i[8] = (TUint8)(aAck.Uint32() >> 24);

		}

	inline void SetHeaderLength(TUint aLength)

		{

		// *NOTE* A very low level function, no sanity

		// checks on value, no rounding up. Value is just

		// truncated and shifted to the proper position

		// (all other bits of this byte should always

		// be zero!)

		i[12] = (TUint8)((aLength >> 2) <<4);

		}

	//

	// A set method for each individual Control Bit is provided

	// (It remains to be seen whether this is sensible or not).

	//

	inline void SetFIN()

		{

		i[13] |= KTcpCtlFIN;

		}

	inline void SetSYN()

		{

		i[13] |= KTcpCtlSYN;

		}

	inline void SetRST()

		{

		i[13] |= KTcpCtlRST;

		}

	inline void SetPSH()

		{

		i[13] |= KTcpCtlPSH;

		}

	inline void SetACK()

		{

		i[13] |= KTcpCtlACK;

		}

	inline void SetURG()

		{

		i[13] |= KTcpCtlURG;

		}

	// Set ECN Echo flag [RFC 3168].

	inline void SetECE()

		{

		i[13] |= KTcpCtlECE;

		}

	// Set ECN Congestion Window Reduced [RFC 3168].

	inline void SetCWR()

		{

		i[13] |= KTcpCtlCWR;

		}

	//

	// Note: does not touch the unused control bits at 12th byte!!!

	//

	inline void SetControl(TUint8 aFlags)

		{

		i[13] = aFlags;

		}

	//

	inline void SetWindow(TUint aWin)

		{

		i[15] = (TUint8)aWin;

		i[14] = (TUint8)(aWin >> 8);

		}

	inline void SetChecksum(TUint aSum)

		{

		// Checksum is used in network byte order

		*((TUint16 *)&i[16]) = (TUint16)aSum;

		}

	inline void SetUrgent(TUint aOff)

		{

		i[19] = (TUint8)aOff;

		i[18] = (TUint8)(aOff >> 8);

		}

	inline TInt SetOptions(TTcpOptions& aOptions)

		{

		TInt optLen = aOptions.OutputOptions(i + KTcpMinHeaderLength, KTcpMaxOptionLength);

		SetHeaderLength(KTcpMinHeaderLength + optLen);

		return optLen;

		}

protected:

	TUint8 i[KTcpMaxHeaderLength];

	};

/** @} */

#endif