// 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