/*

* Copyright (c) 2005-2009 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: 

* Class CIkev2NatT implements NAT Traversal functionality specified in IKEv2.

*

*/

#include <in_sock.h>

#include "ikev2natt.h"

#include "ikev2SAdata.h"

#include "ikev2payloads.h"

#include "ikev2const.h"

#include "ikecrypto.h"

CIkev2NatT* CIkev2NatT::NewL(const TInetAddr& aSourceAddr, const TInetAddr& aDestinationAddr, TUint16 aPort, 

                             const TDesC8& aInitiatorSpi, const TDesC8& aResponderSpi)

{

    CIkev2NatT* self = new (ELeave)CIkev2NatT();

	CleanupStack::PushL(self);		

	self->ConstructL(aSourceAddr, aDestinationAddr, aPort, aInitiatorSpi, aResponderSpi);

	CleanupStack::Pop(self);			

    return self;

}

void CIkev2NatT::ConstructL(const TInetAddr& aSourceAddr, const TInetAddr& aDestinationAddr, TUint16 aPort, 

                            const TDesC8& aInitiatorSpi, const TDesC8& aResponderSpi)

{

	iSrcNotify = GenerateNatDetectionHashL(aInitiatorSpi, aResponderSpi,

                                           aSourceAddr, aPort);

	iDstNotify = GenerateNatDetectionHashL(aInitiatorSpi, aResponderSpi,

                                           aDestinationAddr, aPort);

}

TUint32 CIkev2NatT::CheckPeerNotifysL(const CArrayFixFlat<TNotifPayloadIkev2*>& aNotifys, 

                                      const TInetAddr& aLocalAddr, const  TInetAddr& aRemoteAddr, TUint16 aPort, 

									  const TDesC8& aInitiatorSpi, const TDesC8& aResponderSpi, TBool& aSupported)

{    

  //

  // Check does there exists NAT_DETECTION_SOURCE_IP and NAT_DETECTION_DESTINATION_IP

  // Notify payload. If found compare payload data to local end NAT

  // traversal data as follows:

  // -- NAT_DETECTION_SOURCE_IP Notifys are examined against local Notify

  //    payload iDstIdentiy data: If no match found

  //    ==> Peer is behind  NAT

  // -- NAT_DETECTION_DESTINATION_IP Notify is examined against local Notify

  //    payload iSrcIdentiy data: If no match found

  //    ==> Local end behind NAT

  //

    aSupported = EFalse;

	TInt Count = aNotifys.Count();

	CIkev2NatT* RefObj = CIkev2NatT::NewL(aLocalAddr, aRemoteAddr, aPort, 

                                          aInitiatorSpi, aResponderSpi);

	TNotifPayloadIkev2* PeerNotify;

	TUint32 PeerLth;

	TBool SrcMatch   = EFalse;

	TBool DstMatch   = EFalse;	

    TUint32 NatFlags = 0;

    TInt i = 0;

	while ( i < Count )

	{

		PeerNotify = aNotifys.At(i);

		if ( (PeerNotify->GetMsgType() == NAT_DETECTION_SOURCE_IP) && !SrcMatch )

		{

			NatFlags |= REMOTE_END_NAT;

			PeerLth = TPayloadIkev2::Cast(PeerNotify)->GetLength() - (TUint32)(PeerNotify->Size() + PeerNotify->GetSPISize());

			const TPtrC8 peerNotify(PeerNotify->NotifData(), PeerLth);

			if ( RefObj->DestinNofify().Compare(peerNotify) == 0)

			{

				SrcMatch  = ETrue;

				NatFlags &= ~REMOTE_END_NAT;

			}	

		}

		else if ( (PeerNotify->GetMsgType() == NAT_DETECTION_DESTINATION_IP) && !DstMatch )

		{

			aSupported = ETrue;						

			NatFlags  |= LOCAL_END_NAT;

			PeerLth = TPayloadIkev2::Cast(PeerNotify)->GetLength() - (TUint32)(PeerNotify->Size() + PeerNotify->GetSPISize()); 

			const TPtrC8 peerNotify(PeerNotify->NotifData(), PeerLth);

			if ( RefObj->SourceNofify().Compare(peerNotify) == 0 )

			{

				DstMatch  = ETrue;							

				NatFlags &= ~LOCAL_END_NAT;

			}	

		}			

	    i ++;

    }

	delete RefObj;	

    return NatFlags;     

}

HBufC8* CIkev2NatT::GenerateNatDetectionHashL(const TDesC8& aInitiatorSpi, const TDesC8& aResponderSpi,

                                              TInetAddr aIpAddress, TUint16 aPort ) const

{

    __ASSERT_DEBUG( aInitiatorSpi.Length() == IKEV2_SPI_SIZE, User::Invariant());

    __ASSERT_DEBUG( aResponderSpi.Length() == IKEV2_SPI_SIZE, User::Invariant());

    //

    //  Calculate HASH = SHA1(SPIS | IP | Port) both for local- and remote IP address/port

    //

    TBuf8<64> hashInData;  

    hashInData.Append(aInitiatorSpi);

    hashInData.Append(aResponderSpi);

    if ( aIpAddress.Family() == KAfInet )

    {

        TUint32 ipv4addr = ByteOrder::Swap32(aIpAddress.Address());//Put in network order

        hashInData.Append(reinterpret_cast<TUint8*>(&ipv4addr), sizeof(ipv4addr));

    }   

    else

    {

        if ( aIpAddress.IsV4Mapped() )

        {           

           aIpAddress.ConvertToV4();  // IPv4 format

           TUint32 ipv4addr = ByteOrder::Swap32(aIpAddress.Address());//Put in network order           

           hashInData.Append(reinterpret_cast<TUint8*>(&ipv4addr), sizeof(ipv4addr));

        }   

        else

        {

           const TUint8* addr = &aIpAddress.Ip6Address().u.iAddr8[0];  //Address in a bytestream

           hashInData.Append(addr, 16);

        }   

    }

    aPort = ByteOrder::Swap16(aPort);

    hashInData.Append(reinterpret_cast<TUint8*>(&aPort), sizeof(aPort));

    return IkeCrypto::PrfL(hashInData, PRF_HMAC_SHA1);

}