/*

* Copyright (c) 2005 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:    implementation

*

*/

#include "tsrtpstreaminstatelatebind.h"

#include "msrtpstreamincontext.h"

#include "msrtpcryptohandlercontext.h"

#include "msrtpcryptohandlercontextrtp.h"

#include "msrtpcryptohandlercontextrtcp.h"

#include "srtputils.h"

// ----------------------------------------------------------------------------

// TSRTPStreamInStateLateBind::TSRTPStreamInStateLateBind

// ----------------------------------------------------------------------------

//

TSRTPStreamInStateLateBind::TSRTPStreamInStateLateBind(

    MSRTPStreamInContext& aStreamContext,

    MSRTPCryptoHandlerContextRTP& aCryptoHandlerRTPContext,

    MSRTPCryptoHandlerContextRTCP& aCryptoHandlerRTCPContext)

    : TSRTPStreamInStateBase(aStreamContext,

                            aCryptoHandlerRTPContext, 

                            aCryptoHandlerRTCPContext)

    {

    }

// ----------------------------------------------------------------------------

// TSRTPStreamInStateLateBind::DoUnprotectSrtpL

// ----------------------------------------------------------------------------

//		

HBufC8* TSRTPStreamInStateLateBind::DoUnprotectSrtpL(const TDesC8& aPacket)

    {

    SRTP_DEBUG_DETAIL( "TSRTPStreamInStateLateBind::DoUnprotectSrtpL ENTRY");

   	SRTP_DEBUG_TINT_VALUE( "Encrypted PacketLength is", aPacket.Length() );                 

    // first initialize current encrypted RTP packet..

    iCryptoHandlerRTPContext.InitializeEncryptedPacketL(aPacket);    

    // for the first RTP packet, we need to set 

    // receiver s_l value to current sequence number, see RFC

    iCryptoHandlerRTPContext.SetReceiver_s_l();

    // Step 2 (in RFC 3711, section 3.3):

    // count the packet index i

    iCryptoHandlerRTPContext.CountReceiverPacketIndexL();

  	SRTP_DEBUG_DETAIL( "CheckMasterKeyIdentifier" );

    // check MKI if it is used

    iCryptoHandlerRTPContext.CheckMasterKeyIdentifierL();

   	SRTP_DEBUG_DETAIL( "DeriveSessionKeysL" );

    // derive session keys..

    iCryptoHandlerRTPContext.DeriveSessionKeysL();

    // do the replay protection, based on sender packetIndex 

    //note that in RCC mode, it set packet index as sender one

    iCryptoHandlerRTPContext.ReplayProtectionL();

    SRTP_DEBUG_DETAIL( "AuthenticateL" );

    // do the authentication (integrity check)

    iCryptoHandlerRTPContext.AuthenticateL();

    /*

    if "error in authentication"

        "clear Crypto Handler"

        go to the uninitialized state

    iStreamContext.ChangeRTPState(MSRTPStreamInContext::ESRTPStreamInUninitialized);    

    */

  	SRTP_DEBUG_DETAIL( "DecryptL" );

     // step 6 decrypt..

    HBufC8* decryptedPacket = iCryptoHandlerRTPContext.DecryptL();

    // Step 7, conditional update s_l and ROC values..

    // (in RFC 3711, section 3.3):         

    iCryptoHandlerRTPContext.Update_s_l_and_RocL();

    iCryptoHandlerRTPContext.AddReplayIndex(); 

    // first RTP packet successfully decrypted..

    // session keys derived etc..

    // we can go to normal state

    SRTP_DEBUG_DETAIL( "ChangeStreamIn State to Normal" );

    iStreamContext.ChangeRTPState(MSRTPStreamInContext::ESRTPStreamInNormal);

    SRTP_DEBUG_TINT_VALUE( "the decrypted packet Length is", decryptedPacket->Length());            

    SRTP_DEBUG_DETAIL( "TSRTPStreamInStateLateBind::DoUnprotectSrtpL EXIT");

    // return decrypted RTP packet

    return decryptedPacket;    

    }

// ----------------------------------------------------------------------------

// TSRTPStreamInStateLateBind::DoUnprotectSrtcpL

// ----------------------------------------------------------------------------

//		

HBufC8* TSRTPStreamInStateLateBind::DoUnprotectSrtcpL(const TDesC8& aPacket)

    {

     // first initialize current encrypted RTP packet..

    iCryptoHandlerRTCPContext.InitializeEncryptedPacketL(aPacket);    

    //(in RFC 3711, section 3.4):

    // count the packet index i

    iCryptoHandlerRTCPContext.ReceiverPacketIndexL();

    // check MKI if it is used

    iCryptoHandlerRTCPContext.CheckMasterKeyIdentifierL();

    // derive session keys..

    iCryptoHandlerRTCPContext.DeriveSessionKeysL();

    // do the replay protection 

    iCryptoHandlerRTCPContext.ReplayProtectionL();

    // do the authentication (integrity check)

    iCryptoHandlerRTCPContext.AuthenticateL();

     // decrypt..

    HBufC8* decryptedPacket = iCryptoHandlerRTCPContext.DecryptL();

    iCryptoHandlerRTCPContext.AddReplayIndex(); 

    // first RTP packet successfully decrypted..

    // session keys derived etc..

    // we can go to normal state

    iStreamContext.ChangeRTCPState(MSRTPStreamInContext::ESRTPStreamInNormal);

    // return decrypted RTP packet

    return decryptedPacket;    

    }