/*

* Copyright (c) 2008-2009 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:  VPN PFKEY extension data utility

*

*/

#include <in_sock.h>

#include <networking/pfkeyv2.h>

#include <networking/pfkeyext.h>

#include "ikemsgheader.h"

#include "pfkeyextdatautil.h"

// ======== MEMBER FUNCTIONS ========

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

// This static method builds a generic PFKEY API extension data for IPSEC.

// This data contains all parameters needed by the IPSEC to do UDP

// encapsulation/decpsulation for ESP packet. Generic extension data format is

// LID format begining with four bytes extension header. Extension header

// consists two bytes extension length and two bytes  extension ID. LID format

// consists from one byte length, one byte ID and parameter data. 

// Buffer format: HL,HID,LID,LID,...LID

// Generic extension data buffer handling macros are defined in pfkeyext.h

// (common macros with IPSEC)

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

//

void PFKeyExtDataUtil::BuildUdpEncExtensionData( TDes8& aExtData,

                                                 TUint32 aNAT_D_Flags,

                                                 TBool aNATDetected,

                                                 TBool aNokiaNATProbeUsed,

                                                 TUint16 aUdpEncapsPort,

                                                 TUint16 aKeepAliveTimeout,

                                                 const TInetAddr& aDestinAddr,

                                                 const TInetAddr& aOriginalAddr )

    {

    if ( aNAT_D_Flags )

        {

        aUdpEncapsPort = FLOATED_IKE_PORT; // for IETF specified ESP UDP encapsulation

        if ( ( aNAT_D_Flags & LOCAL_END_NAT ) == 0 )

            {

            aKeepAliveTimeout = 0; // Local end is not behind NAT, no keepalive needed

            }

        }

    else

        {

        //

        // Nokia specific NAT traversal info (=ESP UDP tunneling)  

        // If aNATDetected is true connection is over NAT:ted

        // network (=local end behind NAT). UDP encapsulation shall

        // then be done using configured port iEspUdpPort. If that

        // value is undefined default port 9872 shall be used then.

        // If aNATDetected is false and aNokiaNATProbeUsed is true

        // the NAT probe procedure has confirmed that there is no

        // NAT device between. ESP UDP encapsulation port is zeroed

        // then to avoid unnecessary ESP UDP encapsulation.

        // If aNokiaNATProbeUsed is false ESP UDP encapsulation is done

        // without probing, if any aUdpEncapsPort is defined 

        //

        if ( !aNATDetected && aNokiaNATProbeUsed )

            {

            aUdpEncapsPort = 0;

            }

        }   

    if ( aUdpEncapsPort == 0 )

        {

        aExtData.SetLength(0); // No extension data needed

        return;

        }

    TPfkeyGenExtension NatExtension( aExtData, ESP_UDP_ENCAPSULATION_EXT );

    NatExtension.StoreParameter( UDP_ENCAPSULATION_PORT,

                                 2,

                                 (TUint8*)&aUdpEncapsPort );

    if ( aKeepAliveTimeout )

        {

        NatExtension.StoreParameter( NAT_KEEPALIVE_TIMEOUT,

                                     2,

                                     (TUint8*)&aKeepAliveTimeout );

        }

    if ( aNAT_D_Flags & REMOTE_END_NAT )

        {

        NatExtension.StoreParameter( DESTINATION_ADDRESS,

                                     sizeof(TInetAddr),

                                     (TUint8*)&aDestinAddr );

        }

    if ( aOriginalAddr.Family() != KAFUnspec )

        {

        NatExtension.StoreParameter( PEER_ORIGINAL_ADDRESS,

                                     sizeof(TInetAddr),

                                     (TUint8*)&aOriginalAddr );

        }       

    }