/*

* Copyright (c) 2006-2007 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:   

*

*/

#ifndef CNATFWUNSAFTCPRELAYPACKET_H

#define CNATFWUNSAFTCPRELAYPACKET_H

#include <e32base.h>

/**

* A class for UNSAF TCP relay packets

*

*  @lib natfwunsafprotocols.lib

*  @since S60 3.2

*/

class CNATFWUNSAFTcpRelayPacket : public CBase

    {

public: // Enumerations

    enum TFrame // draft-ietf-behave-turn-02

        {

        EFrameTypeOffset     = 0,

        EFrameLengthOffset   = 2,

        EFrameTypePrefixMask = 0xff00,

        EFrameSize           = 4

        };

    enum TRelayType

        {

        EFrameTypeStun       = 0x02,

        EFrameTypeData       = 0x03,

        };

public: // Constructors and destructor

    /**

    * Creates a CNATFWUNSAFTcpRelayPacket instance

    * @param aData Data to be relayed

    * @param aType Type of relay (STUN/DATA)

    * @return A new instance of CNATFWUNSAFTcpRelayPacket

    */

    IMPORT_C static CNATFWUNSAFTcpRelayPacket*

                NewL(const TDesC8& aData, const TRelayType aType);

    /**

    * Creates a CNATFWUNSAFTcpRelayPacket instance

    * @param aData Data to be relayed

    * @param aType Type of relay (STUN/DATA)

    * @return A new instance of CNATFWUNSAFTcpRelayPacket

    */

    IMPORT_C static CNATFWUNSAFTcpRelayPacket*

                NewLC(const TDesC8& aData, const TRelayType aType);

    /**

    * Creates a CNATFWUNSAFTcpRelayPacket instance.

    * @param aData Data to be relayed

    * @param aType Type of relay (STUN/DATA)

    * @return A new instance of CNATFWUNSAFTcpRelayPacket

    *       ownership is transferred.

    */

    static CNATFWUNSAFTcpRelayPacket*

        CreateL(const TDesC8& aData, const TRelayType aType);

    /**

    * Destructor, deletes the resources of CNATFWUNSAFTcpRelayPacket.

    */

    virtual ~CNATFWUNSAFTcpRelayPacket();

public: // New functions

    /**

    * Encodes a relay packet

    * @return The encoded UNSAF TCP relay packet. The ownership is

    *         transferred.

    */

    IMPORT_C CBufBase* EncodeL() const;

    /**

    * Returns the relayed data

    * @return relayed data

    */

    IMPORT_C const TDesC8& Data() const;

    /**

    * Returns the relay type

    * @return relay type

    */

    IMPORT_C TRelayType Type() const;

    /**

    * Retrieves the UNSAF TCP relay packet length from a UNSAF TCP relay

    * packet header.

    * @param aNATFWUNSAFTcpRelayPacket a UNSAF TCP relay packet

    * @return KErrNotFound if length field cannot be parsed.

    *         Otherwise the value of the length field.

    */

    static TInt RelayLength(const TDesC8& aNATFWUNSAFTcpRelayPacket);

    /**

    * Writes the length field into WUNSAF TCP relay packet header.

    * @param aNATFWUNSAFTcpRelayPacket Encoded UNSAF TCP relay packet

    *        whose length is to be calculated and written.

    */

    static void SetRelayLength(CBufBase& aNATFWUNSAFTcpRelayPacket);

    /**

    * Writes the length field into NATFWUNSAF TCP relay packet header.

    * @param aNATFWUNSAFTcpRelayPacket Encoded UNSAF TCP relay packet whose

    *        length is to be set.

    * @param aLength Value to write into the length field.

    */

    static void SetRelayLength(CBufBase& aNATFWUNSAFTcpRelayPacket,

        TInt aLength);

protected: // Constructors

    CNATFWUNSAFTcpRelayPacket();

    /**

    * Second phase constructor.

    * @param aData data to be relayed

    * @param aType type of relay (STUN/DATA)

    */

    void ConstructL(const TDesC8& aData, const TRelayType aType);

private:

    /**

    * Encodes the UNSAF TCP relay packet header.

    * @return The encoded UNSAF relay packet header. The ownership is

    *         transferred.

    */

    CBufBase* EncodeRelayHeaderLC() const;

    /**

    * Checks that the length of relayed data is valid

    * @param aLength Length of the relayed data

    * @leave KErrCorrupt If the length is invalid

    */

    void CheckLengthL(TInt aLength) const;

private: // Data

    //Relayed data, owned

    HBufC8* iData;

    //Relay type

    TRelayType iType;

private:

    enum TValueDataGranularity

        {

        //The length of iValue has to be a multiple of 4

        EGranularity = 4

        };

    };

#endif // CNATFWUNSAFTCPRELAYPACKET_H