/*

* Copyright (c) 2004 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:    Provides class for authentication with HMAC-SHA1 algorithm.

*

*/

#include "srtpauthentication_hmac_sha1.h" 

#include "srtpaesctrcrypto.h"

#include "hash.h"

#include "srtpdef.h"

#include "srtputils.h"

#define DES_AS_8_BIT(str) (TPtrC8((TText8*)((str).Ptr()), (str).Size()))

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

// CSRTPAuthentication_HMAC_SHA1::NewL

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

//

CSRTPAuthentication_HMAC_SHA1* CSRTPAuthentication_HMAC_SHA1::NewL()

    {

    CSRTPAuthentication_HMAC_SHA1* self = CSRTPAuthentication_HMAC_SHA1::NewLC();

    CleanupStack::Pop(self);

    return self;    

    }

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

// CSRTPAuthentication_HMAC_SHA1::NewLC

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

//

CSRTPAuthentication_HMAC_SHA1* CSRTPAuthentication_HMAC_SHA1::NewLC()

    {

    CSRTPAuthentication_HMAC_SHA1* self = new( ELeave ) CSRTPAuthentication_HMAC_SHA1();

    CleanupStack::PushL( self );

    self->ConstructL();

    return self;

    }

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

// SRTPAuthentication_HMAC_SHA1::AuthenticateL

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

//

HBufC8* CSRTPAuthentication_HMAC_SHA1::AuthenticateL(TUint aBitLength,

                                                    const TDesC8& aKey, 

                                                    const TDesC8& aAuthPortion,

                                                    const TDesC8& aRoc)

    {        

    SRTP_DEBUG_DETAIL( "CSRTPAuthentication_HMAC_SHA1::AuthenticateL Entry" );

    TBuf8<20> buf;    

    if (aBitLength != KSRTPAuthTagLength80 && aBitLength != KSRTPAuthTagLength32)

        {

        SRTP_DEBUG_TUINT_VALUE( "aBitLength is not valid", aBitLength );

        User::Leave(KErrArgument);

        }

    // reserve size for 160 bit tag which seems to be the default        

	HBufC8* result = HBufC8::NewL(20);  

	TPtr8 ptrOutputBuff = result->Des();	

    CleanupStack::PushL(result);

    CSHA1* sha1 = CSHA1::NewL(); 

    CleanupStack::PushL(sha1);

    CHMAC *hmac = CHMAC::NewL(aKey, sha1);        

    CleanupStack::Pop(sha1);

    CleanupStack::Pop(result);

    SRTP_DEBUG_TINT_VALUE( "HMAC INPUT and INPUT Length is ", aAuthPortion.Length() );

    SRTP_DEBUG_TINT_VALUE( "HMAC INPUT and INPUT Size is ", aAuthPortion.Size());     

    SRTP_DEBUG_PACKET ( DES_AS_8_BIT(aAuthPortion) );    

    if(aRoc.Length())

    	{

  		hmac->Update(DES_AS_8_BIT(aAuthPortion));

    	buf.Copy(hmac->Final(DES_AS_8_BIT(aRoc))); 	

    	}

    else

    	{

    	buf.Copy(hmac->Final(DES_AS_8_BIT(aAuthPortion)));

    	}

    *result = buf;    

    ptrOutputBuff.SetLength(aBitLength/8);

    delete hmac;

   	SRTP_DEBUG_DETAIL( "HMAC caculated Authentication tag");

    SRTP_DEBUG_PACKET( *result );    

    SRTP_DEBUG_DETAIL( "CSRTPAuthentication_HMAC_SHA1::AuthenticateL Exit" );

    return result;            

    }

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

// CSRTPAuthentication_HMAC_SHA1::ConstructL

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

//

void CSRTPAuthentication_HMAC_SHA1::ConstructL()

    {    

    }

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

// CSRTPAuthentication_HMAC_SHA1::~CSRTPAuthentication_HMAC_SHA1

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

//

CSRTPAuthentication_HMAC_SHA1::~CSRTPAuthentication_HMAC_SHA1()

    {    

    }

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

// CSRTPAuthentication_HMAC_SHA1::CSRTPAuthentication_HMAC_SHA1

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

//

CSRTPAuthentication_HMAC_SHA1::CSRTPAuthentication_HMAC_SHA1()

    {    

    }