windows-server-2003/net/rras/ras/ppp/engine/smevents.c

/********************************************************************/
/**               Copyright(c) 1989 Microsoft Corporation.         **/
/********************************************************************/

//***
//
// Filename:    smevents.c
//
// Description: This module contain the events processing code for the 
//              Finite State Machine for PPP.
//
// History:
//      Oct 25,1993.    NarenG          Created Original version.
//
//

#include <nt.h>
#include <ntrtl.h>
#include <nturtl.h>     // needed for winbase.h

#include <windows.h>    // Win32 base API's
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include <rasauth.h>
#include <raseapif.h>
#include <lmcons.h>
#include <raserror.h>
#include <rasman.h>
#include <rtutils.h>
#include <rasppp.h>
#include <pppcp.h>
#include <ppp.h>
#include <smaction.h>
#include <smevents.h>
#include <receive.h>
#include <auth.h>
#include <callback.h>
#include <lcp.h>
#include <timer.h>
#include <util.h>
#include <worker.h>
#include <bap.h>

static VOID (*ProcessPacket[])( PCB *           pPcb, 
                                DWORD           CpIndex, 
                                CPCB *          pCpCb, 
                                PPP_CONFIG *    pRecvConfig ) = 
{
    NULL,
    ReceiveConfigReq,
    ReceiveConfigAck,
    ReceiveConfigNakRej,
    ReceiveConfigNakRej,
    ReceiveTermReq,
    ReceiveTermAck,
    ReceiveCodeRej,
    NULL,
    ReceiveEchoReq,
    ReceiveEchoReply,
    ReceiveDiscardReq,
    ReceiveIdentification,
    ReceiveTimeRemaining 
};


/************************************************************************/
/*                      E V E N T   P R O C E S S I N G                 */
/************************************************************************/


//**
//
// Call:        FsmUp
//
// Returns:     none.
//
// Description: This is called after a Line Up event occurs.
//
VOID
FsmUp(
    IN PCB *  pPcb,
    IN DWORD  CpIndex
)
{
    CPCB * pCpCb = GetPointerToCPCB( pPcb, CpIndex );

    if ( pCpCb == NULL )
    {
        return;
    }

    PppLog( 2, "FsmUp event received for protocol %x on port %d",
                CpTable[CpIndex].CpInfo.Protocol, pPcb->hPort );

    if ( CpIndex == LCP_INDEX )
    {
        pPcb->PppPhase = PPP_LCP;
    }

    switch( pCpCb->State )
    {

    case FSM_INITIAL:

        pCpCb->State = FSM_CLOSED;

        break;

    case FSM_STARTING:

        InitRestartCounters( pPcb, pCpCb );

        if ( !FsmSendConfigReq( pPcb, CpIndex, FALSE ) )
        {
            //
            // If we couldn't even send the first configure request, we mark
            // this protocol as NOT CONFIGURABLE so that we protocol reject
            // this layer. We need to do this since FsmClose will not send
            // a terminate request in this state (as per the PPP FSM) and we
            // want to terminate this layer gracefully instead of simply
            // dropping all the clients packets and having the client
            // timeout.
            //

            pCpCb->fConfigurable = FALSE;

            return;
        }

        pCpCb->State = FSM_REQ_SENT;

        break;

    default:

        //
        // Already started 
        //

        PPP_ASSERT( pCpCb->State < 10 );

        PppLog( 2, "Illegal transition -> FsmUp received while in %s state",
                   FsmStates[pCpCb->State] );

        break;
    }
}

//**
//
// Call:        FsmOpen
//
// Returns:     None.
//
// Description: This is called after an Open event occurs.
//
VOID
FsmOpen(
    IN PCB *  pPcb,
    IN DWORD  CpIndex
)
{
    CPCB * pCpCb = GetPointerToCPCB( pPcb, CpIndex );

    if ( pCpCb == NULL )
    {
        return;
    }

    PppLog( 2,  "FsmOpen event received for protocol %x on port %d",
                CpTable[CpIndex].CpInfo.Protocol, pPcb->hPort );

    switch( pCpCb->State )
    {

    case FSM_INITIAL:

        if ( !FsmThisLayerStarted( pPcb, CpIndex ) )
            return;

        pCpCb->State = FSM_STARTING;

        break;

    case FSM_STARTING:
    case FSM_REQ_SENT:
    case FSM_ACK_RCVD:
    case FSM_ACK_SENT:

        break;

    case FSM_CLOSING:

        pCpCb->State = FSM_STOPPING;

        //
        // Fallthru
        //

    case FSM_OPENED:
    case FSM_STOPPED:
    case FSM_STOPPING:

        //
        // Restart option not implemented.
        //
        // FsmDown( pPcb, CpIndex );
        // FsmUp( pPcb, CpIndex );
        //

        break;

    case FSM_CLOSED:

        InitRestartCounters( pPcb, pCpCb );

        if ( !FsmSendConfigReq( pPcb, CpIndex, FALSE ) )
            return;

        pCpCb->State = FSM_REQ_SENT;

        break;

    default:

        PPP_ASSERT( pCpCb->State < 10 );

        PppLog( 2, "Illegal transition->FsmOpen received while in %s state",
                   FsmStates[pCpCb->State] );
        break;
    }
}

//**
//
// Call:        FsmDown
//
// Returns:     None.
//
// Description: Will get called after the physical line goes down.
//
VOID
FsmDown(
    IN PCB *    pPcb,
    IN DWORD    CpIndex
)
{
    CPCB *  pCpCb = GetPointerToCPCB( pPcb, CpIndex );

    if ( pCpCb == NULL )
    {
        return;
    }

    PppLog( 2, "FsmDown event received for protocol %x on port %d",
                CpTable[CpIndex].CpInfo.Protocol, pPcb->hPort );

    RemoveFromTimerQ( pPcb->dwPortId,
                      pCpCb->LastId,
                      CpTable[CpIndex].CpInfo.Protocol,
                      FALSE,
                      TIMER_EVENT_TIMEOUT );

    switch( pCpCb->State )
    {

    case FSM_CLOSED:
    case FSM_CLOSING:

        if ( !FsmReset( pPcb, CpIndex ) )
            return;

        pCpCb->State = FSM_INITIAL;

        break;

    case FSM_OPENED:

        if ( !FsmThisLayerDown( pPcb, CpIndex ) )
            return;

        //
        // Fallthru
        //

    case FSM_REQ_SENT:
    case FSM_ACK_RCVD:
    case FSM_ACK_SENT:
    case FSM_STOPPING:

        if ( !FsmReset( pPcb, CpIndex ) )
            return;

        pCpCb->State = FSM_STARTING;

        break;

    case FSM_STOPPED:

        if ( !FsmThisLayerStarted( pPcb, CpIndex ) )
            return;

        if ( !FsmReset( pPcb, CpIndex ) )
            return;

        pCpCb->State = FSM_STARTING;

        break;

    case FSM_STARTING:
    case FSM_INITIAL:
    default:

        PPP_ASSERT( pCpCb->State < 10 );

        PppLog( 2, "Illegal transition->FsmDown received while in %s state",
                   FsmStates[pCpCb->State] );
        break;
    }

    if ( CpIndex == LCP_INDEX )
    {
        pPcb->PppPhase = PPP_LCP;
    }
}

//**
//
// Call:        FsmClose
//
// Returns:     None.
//
// Description: Will get called when a close connection is requested.
//              NOTE: Call FsmThisLayerFinished in the states where we do
//                    not have to send a Term Req. and wait for a Term Ack. 
//                    This is done so that it is guaranteed that 
//                    FsmThisLayerFinished is called in ALL states. We need
//                    to do this since all processing of failures is done in
//                    the FsmThisLayerFinished call.
//                    
VOID
FsmClose(
    IN PCB * pPcb,
    IN DWORD CpIndex
)
{
    CPCB * pCpCb = GetPointerToCPCB( pPcb, CpIndex );

    if ( pCpCb == NULL )
    {
        return;
    }

    PppLog( 2, "FsmClose event received for protocol %x on port %d",
                CpTable[CpIndex].CpInfo.Protocol, pPcb->hPort );

    if ( CpIndex == LCP_INDEX )
    {
        pPcb->PppPhase = PPP_LCP;
    }

    //
    // We are closing this layer so remove any items from the timer Q
    //

    RemoveFromTimerQ( pPcb->dwPortId,
                      pCpCb->LastId,
                      CpTable[CpIndex].CpInfo.Protocol,
                      FALSE,
                      TIMER_EVENT_TIMEOUT );

    switch ( pCpCb->State ) 
    {

    case FSM_STARTING:

        pCpCb->State = FSM_INITIAL;

        if ( !FsmThisLayerFinished( pPcb, CpIndex, FALSE ) )
            return;

        break;

    case FSM_STOPPED:

        pCpCb->State = FSM_CLOSED;

        if ( !FsmThisLayerFinished( pPcb, CpIndex, FALSE ) )
            return;

        break;

    case FSM_STOPPING:

        pCpCb->State = FSM_CLOSING;

        if ( !FsmThisLayerFinished( pPcb, CpIndex, FALSE ) )
            return;

        break;

    case FSM_REQ_SENT:
    case FSM_OPENED:

        if ( !FsmThisLayerDown( pPcb, CpIndex ) )
            return;

        //
        // Fallthru 
        //

    case FSM_ACK_RCVD:
    case FSM_ACK_SENT:

        InitRestartCounters( pPcb, pCpCb );

        //
        // May not be able to do this because the link may be down.
        //

        FsmSendTermReq( pPcb, CpIndex );

        pCpCb->State = FSM_CLOSING;

        break;

    case FSM_CLOSING:
    case FSM_CLOSED:
    case FSM_INITIAL:

        if ( !FsmThisLayerFinished( pPcb, CpIndex, FALSE ) )
            return;

        //
        // nothing to do 
        //

        break;

    default:

        PPP_ASSERT( pCpCb->State < 10 );

        PppLog( 2,"Illegal transition->FsmClose received while in %s state",
                   FsmStates[pCpCb->State] );
        break;

    }
}

//**
//
// Call:        FsmTimeout
//
// Returns:     None
//
// Description: Called to process a timeout while waiting for reply 
//              from remote host.
//
VOID
FsmTimeout(
    IN PCB *    pPcb,
    IN DWORD    CpIndex,
    IN DWORD    Id,
    IN BOOL     fAuthenticator
)
{
    CPCB *      pCpCb  = GetPointerToCPCB( pPcb, CpIndex );
    LCPCB *     pLcpCb = (LCPCB*)(pPcb->LcpCb.pWorkBuf);

    if ( pCpCb == NULL )
    {
        //
        // If we got a timeout for an authentication CB that is no longer
        // active, we just ignore it.
        //

        return;
    }

    PppLog( 2, 
        "Recv timeout event received for portid=%d,Id=%d,Protocol=%x,fAuth=%d",
         pPcb->dwPortId, Id, CpTable[CpIndex].CpInfo.Protocol, fAuthenticator );

    // 
    // If we are authenticating we use the ConfigRetryCount
    //

    if ( CpIndex == GetCpIndexFromProtocol( fAuthenticator
                                                ? pLcpCb->Local.Work.AP
                                                : pLcpCb->Remote.Work.AP ) )
    {
        if ( pPcb->PppPhase == PPP_AP )
        {
            pCpCb = ( fAuthenticator ) 
                        ? &(pPcb->AuthenticatorCb) 
                        : &(pPcb->AuthenticateeCb);

            //
            // Silently discard timeouts for packets with Id < pPcb->LastId
            //

            if ( Id < pCpCb->LastId )
            {
                return;
            }

            if ( pCpCb->ConfigRetryCount > 0 ) 
            {
                (pCpCb->ConfigRetryCount)--;

                ApWork( pPcb, CpIndex, NULL, NULL, fAuthenticator );
            }
            else
            {
                //
                // If an error has already been set, do not change it.
                //

                if ( pPcb->LcpCb.dwError == NO_ERROR )
                {
                    pPcb->LcpCb.dwError = ERROR_PPP_TIMEOUT;
                }

                NotifyCallerOfFailure( pPcb, pPcb->LcpCb.dwError );
            }
        }

        return;
    } 
    else if ( CpIndex == GetCpIndexFromProtocol( PPP_CBCP_PROTOCOL ) )
    {
        if ( pPcb->PppPhase == PPP_NEGOTIATING_CALLBACK )
        {
            //
            // Silently discard timeouts for packets with Id < pPcb->LastId
            //

            if ( Id < pCpCb->LastId )
            {
                return;
            }

            if ( pCpCb->ConfigRetryCount > 0 ) 
            {
                (pCpCb->ConfigRetryCount)--;

                CbWork( pPcb, CpIndex, NULL, NULL );
            }
            else
            {
                //
                // If an error has already been set, do not change it.
                //

                if ( pPcb->LcpCb.dwError == NO_ERROR )
                {
                    pPcb->LcpCb.dwError = ERROR_PPP_TIMEOUT;
                }

                NotifyCallerOfFailure( pPcb, pPcb->LcpCb.dwError );
            }
        }
    }

    //
    // Silently discard timeouts for packets with Id < pPcb->LastId
    //

    if ( Id < pCpCb->LastId )
    {
        return;
    }

    switch( pCpCb->State ) 
    {

    case FSM_REQ_SENT:
    case FSM_ACK_RCVD:
    case FSM_ACK_SENT:

        if ( pCpCb->ConfigRetryCount > 0 ) 
        {
            (pCpCb->ConfigRetryCount)--;

            //
            // If we have not received any PPP frames from the server yet.
            //

            if ( ( CpIndex == LCP_INDEX ) && 
                 ( pPcb->LcpCb.dwError == ERROR_PPP_NO_RESPONSE ) &&
                 ( !(pPcb->fFlags & PCBFLAG_IS_SERVER) ) )
            {
                NotifyCaller( pPcb, PPPMSG_Progress, NULL );
            }

            // If the RestartTimer value is less then the configured 
            // restart timer value, then bump it up by one second.
            //

            if ( pPcb->RestartTimer < PppConfigInfo.DefRestartTimer )
            {
                (pPcb->RestartTimer)++;
            }

            if ( !FsmSendConfigReq( pPcb, CpIndex, TRUE ) ) 
                return;

            if ( pCpCb->State != FSM_ACK_SENT  )
                pCpCb->State = FSM_REQ_SENT;
        } 
        else 
        {
            PppLog( 1, "Request retry exceeded" );

            //
            // If the LCP layer exceeded its retry count
            //

            if ( pCpCb->dwError == NO_ERROR )
            {
                pCpCb->dwError = ERROR_PPP_TIMEOUT;
            }

            if ( !FsmThisLayerFinished( pPcb, CpIndex, TRUE ) )
                return;

            pCpCb->State = FSM_STOPPED;
        }

        break;

    case FSM_CLOSING:
    case FSM_STOPPING:

        if ( pCpCb->TermRetryCount > 0 ) 
        {
            (pCpCb->TermRetryCount)--;

            FsmSendTermReq( pPcb, CpIndex );
        } 
        else 
        {
            PppLog( 1, "Terminate retry exceeded" );

            if ( pCpCb->dwError == NO_ERROR )
            {
                pCpCb->dwError = ERROR_PPP_TIMEOUT;
            }

            if ( !FsmThisLayerFinished( pPcb, CpIndex, TRUE ) )
                return;

            pCpCb->State = ( pCpCb->State == FSM_CLOSING ) ? FSM_CLOSED 
                                                           : FSM_STOPPED;
        }

        break;

    case FSM_OPENED:
    case FSM_INITIAL:
    case FSM_STARTING:
    case FSM_CLOSED:
    case FSM_STOPPED:
    default:

        PPP_ASSERT( pCpCb->State < 10 );

        PppLog( 2, "Illegal transition->FsmTimeout rcvd while in %s state",
                   FsmStates[pCpCb->State] );
        break;
    }
}

//**
//
// Call:        FsmReceive
//
// Returns:     None
//
// Description: Called when a PPP packet is received. Will process the 
//              incomming packet.
//
VOID
FsmReceive(
    IN PCB *        pPcb,
    IN PPP_PACKET * pPacket,
    IN DWORD        dwPacketLength
)
{
    DWORD        dwProtocol;
    DWORD        CpIndex;
    PPP_CONFIG * pRecvConfig;
    CPCB *       pCpCb;
    DWORD        dwLength;
    LCPCB *      pLcpCb         = (LCPCB*)(pPcb->LcpCb.pWorkBuf);
    
    LogPPPPacket( TRUE, pPcb, pPacket, dwPacketLength );
	
    //
    // Validate length of packet
    //

    if ( dwPacketLength < ( PPP_PACKET_HDR_LEN + PPP_CONFIG_HDR_LEN ) ) 
    {
        PppLog( 1, "Silently discarding badly formed packet" );

        return;
    }

    dwProtocol = WireToHostFormat16( pPacket->Protocol );

    CpIndex = GetCpIndexFromProtocol( dwProtocol );

    switch( pPcb->PppPhase )
    {
    case PPP_NEGOTIATING_CALLBACK:

        //
        // Silently discard any packet other than LCP and Authentication 
        // and callback  packets if we are in the callback phase
        //

        if ( CpIndex == GetCpIndexFromProtocol( PPP_CBCP_PROTOCOL ) ) 
            break;

        //
        // Fallthru
        //

    case PPP_AP:

        //
        // Silently discard any packet other than LCP and Authentication 
        // packets if we are in the authentication phase
        //

        if ( CpIndex == GetCpIndexFromProtocol( pLcpCb->Local.Work.AP ) )
            break;

        if ( CpIndex == GetCpIndexFromProtocol( pLcpCb->Remote.Work.AP ) )
            break;

        //
        // If we are the authenticatee being authenticated by EAP, then if we
        // receive an NCP packet we should assume success. We do this by
        // generating a fake EAP_SUCCESS message and send it to the 
        // authenticatee. 
        //

        if (   ( pLcpCb->Remote.Work.AP == PPP_EAP_PROTOCOL )
            && ( pPcb->PppPhase == PPP_AP ) )
        {
            PPPAP_INPUT  ApInput;

            switch( dwProtocol ) 
            {
            case PPP_CBCP_PROTOCOL:
            case PPP_IPCP_PROTOCOL:
            case PPP_ATCP_PROTOCOL:
            case PPP_IPXCP_PROTOCOL:
            case PPP_NBFCP_PROTOCOL:
            case PPP_CCP_PROTOCOL:
            case PPP_BACP_PROTOCOL:

                PppLog( 1,"Received and NCP or CBCP packet before EAP success");

                ZeroMemory( &ApInput, sizeof( ApInput ) );

                ApInput.fSuccessPacketReceived = TRUE;

                CpIndex = GetCpIndexFromProtocol( PPP_EAP_PROTOCOL );

                if ( pPcb->AuthenticateeCb.LastId != (DWORD)-1 )
                {
                    RemoveFromTimerQ(
                          pPcb->dwPortId,
                          pPcb->AuthenticateeCb.LastId,
                          pLcpCb->Remote.Work.AP,
                          FALSE,
                          TIMER_EVENT_TIMEOUT );
                }

                ApWork( pPcb, CpIndex, NULL, &ApInput, FALSE );

                //
                // PppPhase will now be one of PPP_LCP (if ApWork failed),
                // PPP_NCP, or PPP_NEGOTIATING_CALLBACK. We will not call
                // this function recursively again.
                //
            
                //
                // Now process the NCP we received if we have passed 
                // authentication
                //

                if ( ( pPcb->PppPhase == PPP_NCP ) || 
                     ( pPcb->PppPhase == PPP_NEGOTIATING_CALLBACK ) )
                {
                    FsmReceive( pPcb, pPacket, dwPacketLength );
                }

                return;

            default:
        
                break;
            }
        }
             
        //
        // Fallthru
        //

    case PPP_LCP:

        //
        // Silently discard any packet other than LCP if we are in the
        // LCP or termination or authentication phases
        //

        if ( CpIndex != LCP_INDEX )
        {
            PppLog( 1, "Non-LCP packet received when LCP is not opened");
            PppLog( 1, "Packet being silently discarded" );

            return;
        }

        break;

    case PPP_NCP:

        //
        // We do not recognize this protocol
        //

        if ( CpIndex == (DWORD)-1 )
        {
            if ( dwProtocol == PPP_BAP_PROTOCOL )
            {
                CpIndex = GetCpIndexFromProtocol( PPP_BACP_PROTOCOL );

                if (CpIndex != (DWORD)-1)
                {
                    pCpCb = GetPointerToCPCB( pPcb, CpIndex );

                    if ( pCpCb->State == FSM_OPENED )
                    {
                        BapEventReceive( pPcb->pBcb, pPacket, dwPacketLength );
                        return;
                    }
                }

                BapTrace( "BAP packet silently discarded" );
                return;
            }
            
            //
            // If this is a Control Protocol then we reject it, otherwise we
            // we silently discard it.
            // We used to also check if the protocol is less than 0x0000BFFF,
            // but Shiva has proprietary NBFCP with id 0x0000CFEC and we need
            // to protocol reject it.
            //

            if ( dwProtocol >= 0x00008000 ) 
            {
                FsmSendProtocolRej( pPcb, pPacket, dwPacketLength );
            }
            else
            {
                PppLog( 1, "Network-layer packet rcvd."); 
                PppLog( 1, "Packet being silently discarded" );
            }

            return;
        }

        break;

    default:

        PppLog( 1, "Packet received being silently discarded" );
        return;
    }

    pCpCb = GetPointerToCPCB( pPcb, CpIndex );

    pRecvConfig = (PPP_CONFIG*)(pPacket->Information);

    //
    // We received a PPP packet so the remote host does support it
    //

    if ( pPcb->LcpCb.dwError == ERROR_PPP_NO_RESPONSE )
    {
        pPcb->LcpCb.dwError = NO_ERROR;
    }

    //
    // If we received a packet for a protocol that we have but do not
    // wish to configure then we send a configure reject.
    //

    if ( ( pCpCb == NULL ) || !(pCpCb->fConfigurable) )
    {
        FsmSendProtocolRej( pPcb, pPacket, dwPacketLength );

        return;
    }

    dwLength = WireToHostFormat16( pRecvConfig->Length );

    if ( ( dwLength > ( dwPacketLength - PPP_PACKET_HDR_LEN ) ) || 
         ( dwLength < PPP_CONFIG_HDR_LEN ) )
    {
        PppLog( 1,"Silently discarding badly formed packet" );

        return;
    }

    //
    // Not in ProcessPacket table since parameters to this are different.
    //

    if ( ( CpIndex == LCP_INDEX ) && ( pRecvConfig->Code == PROT_REJ ) )
    {
        ReceiveProtocolRej( pPcb, pPacket );

        return;
    }

    //
    // Make sure that the protocol can handle the config code sent.
    //

    if ( ( pRecvConfig->Code == 0 ) ||
         !( pRecvConfig->Code < CpTable[CpIndex].CpInfo.Recognize )  )
    {
        ReceiveUnknownCode( pPcb, CpIndex, pCpCb, pRecvConfig );

        return;
    }

    //
    // If we received an authentication packet. 
    //

    if ( CpIndex == GetCpIndexFromProtocol( pLcpCb->Local.Work.AP ) )
    {
        if ( ApIsAuthenticatorPacket( CpIndex, pRecvConfig->Code ) )
        {
            if ( pPcb->AuthenticatorCb.LastId != (DWORD)-1 ) 
            {
                //
                // If we have just received a packet we have been waiting for
                // then we stop the outstanding timout for it. We let the
                // APs do the Id matching.
                //

                if ( pRecvConfig->Id == pPcb->AuthenticatorCb.LastId )
                {
                    RemoveFromTimerQ( 
                          pPcb->dwPortId,
                          pPcb->AuthenticatorCb.LastId,
                          pLcpCb->Local.Work.AP,
                          TRUE,
                          TIMER_EVENT_TIMEOUT );
                }
            }

            ApWork( pPcb, CpIndex, pRecvConfig, NULL, TRUE );

            return;
        }
        else if ( CpIndex != GetCpIndexFromProtocol( pLcpCb->Remote.Work.AP ) )
        {
            //
            // Silently drop invalid packet, ie. Authenticatee's packet sent 
            // using Authenticater's protocol
            //

            PppLog( 1,
              "Authentication packet received being silently discarded");

            return;
        }
    }

    if ( CpIndex == GetCpIndexFromProtocol( pLcpCb->Remote.Work.AP ) )
    {
        if ( !ApIsAuthenticatorPacket( CpIndex, pRecvConfig->Code ) )
        {
            if ( pPcb->AuthenticateeCb.LastId != (DWORD)-1 )
            {
                //
                // If we have just received a packet we have been waiting for
                // then we stop the outstanding timout for it. We let the
                // APs do the Id matching.
                //

                if ( pRecvConfig->Id == pPcb->AuthenticateeCb.LastId )
                {
                    RemoveFromTimerQ(
                          pPcb->dwPortId,
                          pPcb->AuthenticateeCb.LastId,
                          pLcpCb->Remote.Work.AP,
                          FALSE,
                          TIMER_EVENT_TIMEOUT );
                }
            }

            ApWork( pPcb, CpIndex, pRecvConfig, NULL, FALSE );
        }
        else
        {
            //
            // Silently drop invalid packet, ie. Authenticator's packet sent 
            // using Authenticatee's protocol
            //

            PppLog( 1, 
                    "Authentication packet received being silently discarded");
        }

        return;
    }

    if ( CpIndex == GetCpIndexFromProtocol( PPP_CBCP_PROTOCOL ) ) 
    {
        if ( pCpCb->LastId != (DWORD)-1 )
        {
            //
            // If we have just received a packet we have been waiting for
            // then we stop the outstanding timout for it. We let the
            // CBCP do the Id matching.
            //

            if ( pRecvConfig->Id == pCpCb->LastId )
            {
                RemoveFromTimerQ( 
                          pPcb->dwPortId,
                          pCpCb->LastId, 
                          PPP_CBCP_PROTOCOL,
                          FALSE,
                          TIMER_EVENT_TIMEOUT );
            }
        }
        
        CbWork( pPcb, CpIndex, pRecvConfig, NULL );

    }
    else
    {
        //
        // Any combination of packets allowed here.
        //
		//if this is any packet and not Echo request packet,
		//and if the flag is set then reset the flag.
		if ( pRecvConfig->Code != ECHO_REPLY )
		{
			if ( pPcb->fEchoRequestSend ) pPcb->fEchoRequestSend = 0;
		}
        (*ProcessPacket[pRecvConfig->Code])(pPcb, CpIndex, pCpCb, pRecvConfig);
    }
}