porttcp.c

freemodbus-v1-1-1-0.zip v1.1.1版本的代码 支持多个平台

/*
 * FreeModbus Libary: Win32 Port
 * Copyright (C) 2006 Christian Walter <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * File: $Id: porttcp.c,v 1.2 2006/06/26 19:24:07 wolti Exp $
 */

/*
 * Design Notes:
 *
 * The xMBPortTCPInit function allocates a socket and binds the socket to
 * all available interfaces ( bind with INADDR_ANY ). In addition it
 * creates an array of event objects which is used to check the state of
 * the clients. On event object is used to handle new connections or
 * closed ones. The other objects are used on a per client basis for
 * processing.
 */

#include <stdio.h>
#include "winsock2.h"

#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbport.h"

/* ----------------------- MBAP Header --------------------------------------*/
#define MB_TCP_UID          6
#define MB_TCP_LEN          4
#define MB_TCP_FUNC         7

/* ----------------------- Defines  -----------------------------------------*/
#define MB_TCP_DEFAULT_PORT 502 /* TCP listening port. */
#define MB_TCP_POOL_TIMEOUT 50  /* pool timeout for event waiting. */
#define MB_TCP_READ_TIMEOUT 1000        /* Maximum timeout to wait for packets. */
#define MB_TCP_READ_CYCLE   100 /* Time between checking for new data. */

#define MB_TCP_DEBUG        1   /* Set to 1 for additional debug output. */

#define MB_TCP_BUF_SIZE     ( 256 + 7 ) /* Must hold a complete Modbus TCP frame. */

#define EV_CONNECTION       0
#define EV_CLIENT           1
#define EV_NEVENTS          EV_CLIENT + 1

/* ----------------------- Static variables ---------------------------------*/
SOCKET          xListenSocket;
SOCKET          xClientSocket;
WSAEVENT        xEvents[EV_NEVENTS];

static UCHAR    aucTCPBuf[MB_TCP_BUF_SIZE];
static USHORT   usTCPBufPos;
static USHORT   usTCPFrameBytesLeft;

/* ----------------------- External functions -------------------------------*/
TCHAR          *WsaError2String( DWORD dwError );

/* ----------------------- Static functions ---------------------------------*/
BOOL            prvMBTCPPortAddressToString( SOCKET xSocket, LPTSTR szAddr, USHORT usBufSize );
LPTSTR          prvMBTCPPortFrameToString( UCHAR * pucFrame, USHORT usFrameLen );
static BOOL     prvbMBPortAcceptClient( void );
static void     prvvMBPortReleaseClient( void );
static BOOL     prvMBTCPGetFrame( void );

/* ----------------------- Begin implementation -----------------------------*/

BOOL
xMBTCPPortInit( USHORT usTCPPort )
{
    BOOL            bOkay = FALSE;
    USHORT          usPort;
    SOCKADDR_IN     xService;
    WSADATA         wsaData;

    int             i;

    if( WSAStartup( MAKEWORD( 2, 2 ), &wsaData ) != 0 )
    {
        return FALSE;
    }

    if( usTCPPort == 0 )
    {
        usPort = MB_TCP_DEFAULT_PORT;
    }
    else
    {
        usPort = ( USHORT ) usTCPPort;
    }

    xService.sin_family = AF_INET;
    xService.sin_port = htons( usPort );
    xService.sin_addr.s_addr = INADDR_ANY;

    xClientSocket = INVALID_SOCKET;
    for( i = 0; i < EV_NEVENTS; i++ )
    {
        if( ( xEvents[i] = WSACreateEvent(  ) ) == WSA_INVALID_EVENT )
            break;
    }
    if( i != EV_NEVENTS )
    {
        vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't create event objects: %s\r\n" ),
                    WsaError2String( WSAGetLastError(  ) ) );
    }
    else if( ( xListenSocket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP ) ) == INVALID_SOCKET )
    {
        vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't create socket: %s\r\n" ),
                    WsaError2String( WSAGetLastError(  ) ) );
    }
    else if( bind( xListenSocket, ( SOCKADDR * ) & xService, sizeof( xService ) ) == SOCKET_ERROR )
    {
        vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't bind on socket: %s\r\n" ),
                    WsaError2String( WSAGetLastError(  ) ) );
    }
    else if( listen( xListenSocket, 5 ) == SOCKET_ERROR )
    {
        vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't listen on socket: %s\r\n" ),
                    WsaError2String( WSAGetLastError(  ) ) );
    }
    else if( WSAEventSelect( xListenSocket, xEvents[EV_CONNECTION], FD_ACCEPT ) == SOCKET_ERROR )
    {
        vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't enable events on socket: %s\r\n" ),
                    WsaError2String( WSAGetLastError(  ) ) );
    }
    else
    {
        vMBPortLog( MB_LOG_INFO, _T( "TCP-POLL" ), _T( "Modbus TCP server listening on %S:%d\r\n" ),
                    inet_ntoa( xService.sin_addr ), ntohs( xService.sin_port ) );
        bOkay = TRUE;
    }

    /* Perform cleanup on error. */
    if( bOkay != TRUE )
    {
        for( i = 0; i < EV_NEVENTS; i++ )
        {
            if( xEvents[i] != WSA_INVALID_EVENT )
                WSACloseEvent( xEvents[i] );
        }
        if( xListenSocket != SOCKET_ERROR )
            closesocket( xListenSocket );
    }

    return bOkay;
}

void
vMBTCPPortClose(  )
{
    int             i;

    /* Release all event handlers. */
    for( i = 0; i < EV_NEVENTS; i++ )
    {
        if( xEvents[i] != WSA_INVALID_EVENT )
            WSACloseEvent( xEvents[ i ] );
    }
    /* Close all client sockets. */
    if( xClientSocket != SOCKET_ERROR )
    {
        prvvMBPortReleaseClient(  );
    }
    /* Close the listener socket. */
    if( xListenSocket != SOCKET_ERROR )
    {
        closesocket( xListenSocket );
    }
    ( void )WSACleanup(  );
}

void
vMBTCPPortDisable( void )
{
    /* Close all client sockets. */
    if( xClientSocket != SOCKET_ERROR )
    {
        prvvMBPortReleaseClient(  );
    }
}

/*! \ingroup port_win32tcp
 *
 * \brief Pool the listening socket and currently connected Modbus TCP clients
 *   for new events.
 * \internal
 *
 * This function checks if new clients want to connect or if already connected 
 * clients are sending requests. If a new client is connected and there are 
 * still client slots left (The current implementation supports only one)
 * then the connection is accepted and an event object for the new client
 * socket is activated (See prvbMBPortAcceptClient() ).
 * Events for already existing clients in \c FD_READ and \c FD_CLOSE. In case of
 * an \c FD_CLOSE the client connection is released (See prvvMBPortReleaseClient() ).
 * In case of an \c FD_READ command the existing data is read from the client
 * and if a complete frame has been received the Modbus Stack is notified.
 *
 * \return FALSE in case of an internal I/O error. For example if the internal
 *   event objects are in an invalid state. Note that this does not include any 
 *   client errors. In all other cases returns TRUE.
 */
BOOL
xMBPortTCPPool( void )
{

    BOOL            bOkay = TRUE;
    DWORD           dwWaitResult;
    WSANETWORKEVENTS xNetworkEvents;
    int             iEventNr;
    int             iRes;

    dwWaitResult = WSAWaitForMultipleEvents( EV_NEVENTS, xEvents, FALSE,
                                             MB_TCP_POOL_TIMEOUT, FALSE );

    /* Do nothing because only the timeout has expired. */
    if( ( dwWaitResult == WAIT_IO_COMPLETION ) || ( dwWaitResult == WSA_WAIT_TIMEOUT ) )
    {
    }
    /* Waiting for events failed. */
    else if( dwWaitResult == WSA_WAIT_FAILED )
    {
        vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't wait for network events: %s" ),
                    WsaError2String( WSAGetLastError(  ) ) );
        bOkay = FALSE;
    }
    /* A event occured on one of the sockets */
    else
    {
        /* Get the event number for the result of the wait operation. */
        iEventNr = dwWaitResult - WSA_WAIT_EVENT_0;

        /* A client wants to connect. */
        if( iEventNr == EV_CONNECTION )
        {
            if( MB_TCP_DEBUG )
            {
                vMBPortLog( MB_LOG_DEBUG, _T( "TCP-POLL" ), _T( "got EV_CONNECTION event\r\n" ) );
            }

            /* Get additional event information from the socket. In addition the event
             * object is reseted. 
             */
            iRes = WSAEnumNetworkEvents( xListenSocket, xEvents[iEventNr], &xNetworkEvents );
            if( iRes == SOCKET_ERROR )
            {
                vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't get event list: %S\r\n" ),
                            WsaError2String( WSAGetLastError(  ) ) );
            }
            else if( xNetworkEvents.lNetworkEvents & FD_ACCEPT )
            {
                /* A new connection from a client. Accept it. */
                ( void )prvbMBPortAcceptClient(  );
            }
        }

        /* An already connected client has new data or the connection has 
         * been closed. */
        else if( iEventNr == EV_CLIENT )
        {
            if( MB_TCP_DEBUG )
            {
                vMBPortLog( MB_LOG_DEBUG, _T( "TCP-POLL" ), _T( "got EV_CLIENT event\r\n" ) );
            }

            iRes = WSAEnumNetworkEvents( xClientSocket, xEvents[iEventNr], &xNetworkEvents );
            if( iRes == SOCKET_ERROR )
            {
                vMBPortLog( MB_LOG_ERROR, _T( "TCP-POLL" ), _T( "can't get event list: %s\r\n" ),
                            WsaError2String( WSAGetLastError(  ) ) );
            }
            else if( xNetworkEvents.lNetworkEvents & FD_READ )
            {
                if( MB_TCP_DEBUG )