Diff: ModBus/porttcp.cpp

Revision:

0:62be54b8975d

Child:

1:e35ceaa8c758

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ModBus/porttcp.cpp	Tue Mar 13 09:11:49 2012 +0000
@@ -0,0 +1,312 @@
+/*
+ * FreeModbus Libary: mbed Port
+ * Copyright (C) 2006 Christian Walter <wolti@sil.at>
+ *
+ * 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 1.1 2006/08/30 23:18:07 wolti Exp $
+ */
+/* ----------------------- System includes ----------------------------------*/
+#include <stdio.h>
+#include <string.h>
+
+#include "port.h"
+
+/* ----------------------- mbed includes ------------------------------------*/
+#include "mbed.h"
+#include "EthernetNetIf.h"
+#include "TCPSocket.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_BUF_SIZE     ( 256 + 7 ) /* Must hold a complete Modbus TCP frame. */
+
+/* ----------------------- Prototypes ---------------------------------------*/
+void prvvMBPortReleaseClient(  );
+BOOL prvbMBPortAcceptClient(  );
+BOOL prvMBTCPGetFrame(  );
+void onListeningTCPSocketEvent(TCPSocketEvent e);
+void onConnectedTCPSocketEvent(TCPSocketEvent e);
+
+/* ----------------------- Static variables ---------------------------------*/
+static UCHAR    aucTCPBuf[MB_TCP_BUF_SIZE];
+static USHORT   usTCPBufPos;
+static USHORT   usTCPFrameBytesLeft;
+
+static TCPSocket ListeningSock;
+static TCPSocket* pConnectedSock; // for ConnectedSock
+static Host client;
+
+/* ----------------------- Begin implementation -----------------------------*/
+BOOL
+xMBTCPPortInit( USHORT usTCPPort )
+{
+    BOOL            bOkay = FALSE;
+    USHORT          usPort;
+
+    if( usTCPPort == 0 )
+    {
+        usPort = MB_TCP_DEFAULT_PORT;
+    }
+    else
+    {
+        usPort = ( USHORT ) usTCPPort;
+    }
+    pConnectedSock=NULL;
+
+    // Set the callbacks for Listening
+    ListeningSock.setOnEvent(&onListeningTCPSocketEvent); 
+
+    // bind and listen on TCP
+    if( ListeningSock.bind(Host(IpAddr(), usPort)) )
+    {
+        // Failed to bind
+        bOkay = FALSE;
+    }
+    else if( ListeningSock.listen() )
+    {
+        // Failed to listen
+        bOkay = FALSE;
+    }
+    else
+    {
+#ifdef MB_TCP_DEBUG
+        vMBPortLog( MB_LOG_DEBUG, "MBTCP-ACCEPT", "Protocol stack ready.\r\n" );
+#endif
+        bOkay = TRUE;
+    }    
+
+    return bOkay;
+}
+
+void
+vMBTCPPortClose(  )
+{
+    /* Shutdown any open client sockets. */
+    prvvMBPortReleaseClient();
+
+    /* Shutdown or listening socket. */
+    ListeningSock.close();
+
+    /* Release resources for the event queue. */
+//    vMBPortEventClose(  );
+}
+
+void
+vMBTCPPortDisable( void )
+{
+    prvvMBPortReleaseClient( );
+}
+
+BOOL
+xMBTCPPortGetRequest( UCHAR ** ppucMBTCPFrame, USHORT * usTCPLength )
+{
+    *ppucMBTCPFrame = &aucTCPBuf[0];
+    *usTCPLength = usTCPBufPos;
+
+    /* Reset the buffer. */
+    usTCPBufPos = 0;
+    usTCPFrameBytesLeft = MB_TCP_FUNC;
+    return TRUE;
+}
+
+BOOL
+xMBTCPPortSendResponse( const UCHAR * pucMBTCPFrame, USHORT usTCPLength )
+{
+    BOOL            bFrameSent = FALSE;
+
+    if( pConnectedSock )
+    {
+        if(pConnectedSock->send((char *)pucMBTCPFrame, usTCPLength)>=0)
+        {
+            bFrameSent = TRUE;
+            printf("sent %d bytes\n",usTCPLength);
+        }
+        else
+        {
+            /* Drop the connection in case of an write error. */
+            printf("sent error!\n");
+            prvvMBPortReleaseClient( );
+        }
+    }
+    return bFrameSent;
+}
+
+void
+prvvMBPortReleaseClient(  )
+{
+    if(pConnectedSock){
+        IpAddr clientIp = client.getIp();
+#ifdef MB_TCP_DEBUG
+        vMBPortLog( MB_LOG_DEBUG, "MBTCP-CLOSE", "Closed connection to %d.%d.%d.%d.\r\n",
+             clientIp[0], clientIp[1], clientIp[2], clientIp[3]);
+#endif
+        pConnectedSock->close();
+        pConnectedSock=NULL;
+    }
+}
+
+
+BOOL prvbMBPortAcceptClient(  )
+{
+    // Accepts connection from client and gets connected socket.   
+
+    if (ListeningSock.accept(&client, &pConnectedSock)) {
+        return FALSE; //Error in accept, discard connection
+    }
+    // Setup the new socket events
+    pConnectedSock->setOnEvent(&onConnectedTCPSocketEvent);
+    // We can find out from where the connection is coming by looking at the
+    // Host parameter of the accept() method
+    IpAddr clientIp = client.getIp();
+
+#ifdef MB_TCP_DEBUG
+    vMBPortLog( MB_LOG_DEBUG, "MBTCP-ACCEPT", "Accepted new client %d.%d.%d.%d\r\n",
+        clientIp[0], clientIp[1], clientIp[2], clientIp[3]);
+#endif
+
+    usTCPBufPos = 0;
+    usTCPFrameBytesLeft = MB_TCP_FUNC;
+
+    return TRUE;
+}
+
+
+BOOL
+prvMBTCPGetFrame(  )
+{
+    BOOL            bOkay = TRUE;
+    USHORT          usLength;
+    int             iRes;
+    int i;
+    int total=0;
+    int len;
+    char buf[MB_TCP_BUF_SIZE];
+    /* Make sure that we can safely process the next read request. If there
+     * is an overflow drop the client.
+     */
+    
+    if( ( usTCPBufPos + usTCPFrameBytesLeft ) >= MB_TCP_BUF_SIZE )
+    {
+        // buffer overrun
+        return FALSE;
+    }
+
+    /* Though this part is verbose, it doesn't work when data is recieved directly into aucTCPBuf. */
+    while (len = pConnectedSock->recv(&buf[total], MB_TCP_BUF_SIZE-total) ) {
+        total+=len;
+    }
+
+    if(total>0){
+        memcpy((char *)&aucTCPBuf[usTCPBufPos],buf,total);
+        usTCPBufPos+=total;
+        usTCPFrameBytesLeft-=total;
+        prvMBTCPGetFrame();
+    }
+
+    /* If we have received the MBAP header we can analyze it and calculate
+     * the number of bytes left to complete the current request. If complete
+     * notify the protocol stack.
+     */
+    if( usTCPBufPos >= MB_TCP_FUNC )
+    {
+        /* Length is a byte count of Modbus PDU (function code + data) and the
+         * unit identifier. */
+        usLength = aucTCPBuf[MB_TCP_LEN] << 8U;
+        usLength |= aucTCPBuf[MB_TCP_LEN + 1];
+
+        /* Is the frame already complete. */
+        if( usTCPBufPos < ( MB_TCP_UID + usLength ) )
+        {
+            usTCPFrameBytesLeft = usLength + MB_TCP_UID - usTCPBufPos;
+        }
+        /* The frame is complete. */
+        else if( usTCPBufPos == ( MB_TCP_UID + usLength ) )
+        {
+#ifdef MB_TCP_DEBUG
+            prvvMBTCPLogFrame( "MBTCP-RECV", &aucTCPBuf[0], usTCPBufPos );
+#endif
+            ( void )xMBPortEventPost( EV_FRAME_RECEIVED );
+        }
+        else
+        {
+#ifdef MB_TCP_DEBUG
+            vMBPortLog( MB_LOG_DEBUG, "MBTCP-ERROR",
+                            "Received too many bytes! Droping client.[%d>%d]\r\n" ,usTCPBufPos, MB_TCP_UID + usLength);
+#endif
+            /* This should not happen. We can't deal with such a client and
+             * drop the connection for security reasons.
+             */
+            prvvMBPortReleaseClient(  );
+        }
+    }
+    return bOkay;
+}
+
+
+void onListeningTCPSocketEvent(TCPSocketEvent e)
+{
+    switch(e)
+    {
+    case TCPSOCKET_ACCEPT:
+        if(!prvbMBPortAcceptClient())
+        {
+#ifdef MB_TCP_DEBUG
+            vMBPortLog( MB_LOG_DEBUG, "MBTCP-ERROR", "Error with client connection! Droping it.\r\n" );
+#endif
+            ListeningSock.close();
+        }
+        break;
+
+    default:
+#ifdef MB_TCP_DEBUG
+        vMBPortLog( MB_LOG_DEBUG, "MBTCP-ERROR", "Unexpeted condition!.\r\n" );
+#endif
+        ListeningSock.close();
+        break;
+     };
+}
+
+void onConnectedTCPSocketEvent(TCPSocketEvent e)
+{
+    switch(e)
+    {
+    case TCPSOCKET_READABLE:
+        if(!prvMBTCPGetFrame())prvvMBPortReleaseClient();
+        break;
+    case TCPSOCKET_CONNECTED:
+    case TCPSOCKET_WRITEABLE:
+        break;
+
+    case TCPSOCKET_CONTIMEOUT:
+    case TCPSOCKET_CONRST:
+    case TCPSOCKET_CONABRT:
+    case TCPSOCKET_ERROR:
+    case TCPSOCKET_DISCONNECTED:
+        prvvMBPortReleaseClient();
+        break;
+    default:
+        break;
+    }
+}