// 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:

// Implements the Message sender DHCPIP6 specific access functthat fustions 

// resends messages until max retry or max count has been reached..

// 

//

/**

 @file DHCPIP6MsgSender.cpp

 @internalTechnology

*/

#include "DHCPServer.h"

#include "DHCPIP6MsgSender.h"

#include "DhcpIP6Msg.h"

#include <in_sock.h>

#include <es_sock.h>

/*

the retransmition alg recomended by RFC3315 (DHCPv6). Could be used for DHCPv4 as well

for DHPCv4 doesn't specify anything

   RT for the first message transmission is based on IRT:

      RT = IRT + RAND*IRT

   RT for each subsequent message transmission is based on the previous

   value of RT:

      RT = 2*RTprev + RAND*RTprev

   MRT specifies an upper bound on the value of RT (disregarding the

   randomisation added by the use of RAND).  If MRT has a value of 0,

   there is no upper limit on the value of RT.  Otherwise:

      if (RT > MRT)

     RT = MRT + RAND*MRT

*/

TBool CDHCPIP6MessageSender::SendingContinues() const

/**

  * determines whether to continue the sending

  *

  * 

  * @internalTechnology

  *

  */

	{

	if ( iRetryCount )

		{//EElapsedTime option MUST be the first option in the option part of the message

		//see CDHCPIP6StateMachine::SetMessageHeader fn

		TUint32 elapsedHundrOfSecs = iMicroSecs.Int() / KMicrosecondsInSecs * 100;

		TUint8* elapsedOptionBody = const_cast<TUint8*>(iMsg->Des().Ptr()) + DHCPv6::KDHCPHeaderLength + DHCPv6::KOptionHeaderLength;

		TUint32 current = TBigEndian::GetValue( elapsedOptionBody, DHCPv6::KElapsedTimeOptionLen );

		TBigEndian::SetValue( elapsedOptionBody, DHCPv6::KElapsedTimeOptionLen, current + elapsedHundrOfSecs );

		}

	return iRetryCount < iMaxRetryCount && iRetryDuration < iMaxRetryDuration;

	}

TBool CDHCPIP6MessageSender::CalculateDelay()

/**

  * Calculates the first and the next retransmition time. Returns ETrue is the time calculated

  * is greater than zero.

  *

  * @internalTechnology

  *

  */

    {

    if ( iRetryCount > -1 )

        {

        TInt ms = iMicroSecs.Int();

        ms = iInitialRetryTimeout ? iInitialRetryTimeout : ms + 2*ms + iXid.Rnd( -ms/10, ms/10 );

        if ( ms > iMaxRetryTimeout || ms <= 0 )

            {

            ms = iMaxRetryTimeout + iXid.Rnd( -iMaxRetryTimeout/10, iMaxRetryTimeout/10 );

            }

        iInitialRetryTimeout = 0;

        iMicroSecs = ms;

        }

    else

        {//msg to be send for the first time

        iMicroSecs = iXid.Rnd( 0, iFirstSendDelay );

        }

    return iMicroSecs.Int() > 0;    

    }

void CDHCPIP6MessageSender::SetListener( MMSListener* aMMSListener )

   {

   iMMSListener = aMMSListener;

   }

MMSListener* CDHCPIP6MessageSender::EventListener() const

   {

   return iMMSListener;

   }

void CDHCPIP6MessageSender::SetInitialRetryTimeout( TInt aSeconds )

   {

   iInitialRetryTimeout = KMicrosecondsInSecs * aSeconds;

   }

void CDHCPIP6MessageSender::SetMaxRetryTimeout( TInt aSeconds )

   {

   iMaxRetryTimeout = KMicrosecondsInSecs * aSeconds;

   }

void CDHCPIP6MessageSender::SetMaxRetryCount( TInt aCount )

   {

   iMaxRetryCount = aCount;

   }

void CDHCPIP6MessageSender::SetMaxRetryDuration( TInt aSeconds )

   {

   iMaxRetryDuration = KMicrosecondsInSecs * aSeconds;

   }

void CDHCPIP6MessageSender::SetFirstSendDelay( TInt aSeconds )

   {

   iFirstSendDelay = KMicrosecondsInSecs * aSeconds;

   }