I'm working on win ce 6 modbus tcp client server, application is developed for a client server communication and it is working fine. now req is my slave device should respond to the diff slave addresses polled by master/client. Can I just change slave id and establish connection or I need to close previous connection and again establish new one
below is the code, which is working fine for one node, if I polled with other node ID then it gives exception. what change it req to communicate with other node simultaneously. My device should be able to communicate with 32 diff nodes on modbus tcp. Shall I create individual threads for each node but how they will communicate on same port? before establishing connection with other node shall I close previous node?
startupServer(int slaveAddr, const TCHAR * const hostName)
{
int result;
int tcpOption;
struct sockaddr_in hostAddress;
if (isStarted())
return (FTALK_ILLEGAL_STATE_ERROR);
if ((slaveAddr < -1) || (slaveAddr > 255))
return (FTALK_ILLEGAL_ARGUMENT_ERROR);
this->slaveAddr = slaveAddr;
#ifdef _WINSOCKAPI_
WSADATA wsaData;
result = WSAStartup(0x0101, &wsaData);
if (result != 0)
return (FTALK_SOCKET_LIB_ERROR);
#endif
listenSocket = socket(PF_INET, SOCK_STREAM, 0);
if (listenSocket == INVALID_SOCKET)
{
shutdownServer();
return (FTALK_OPEN_ERR);
}
#ifdef SO_REUSEADDR
tcpOption = 1; setsockopt(listenSocket, SOL_SOCKET, SO_REUSEADDR,
(char *) &tcpOption, sizeof (tcpOption));
#endif
hostAddress.sin_family = AF_INET;
if ((hostName == NULL) || (hostName[0] == '\0'))
hostAddress.sin_addr.s_addr = htonl(INADDR_ANY);
else
{
hostAddress.sin_addr.s_addr = inet_addr((char *) hostName);
#if !defined(__VXWORKS__) // We don't support host name resolving with VxWorks
if (hostAddress.sin_addr.s_addr == INADDR_NONE)
{
struct hostent *hostInfo;
hostInfo = gethostbyname((char *) hostName);
if (hostInfo == NULL)
return (FTALK_TCPIP_CONNECT_ERR);
hostAddress.sin_addr = *(struct in_addr *) hostInfo->h_addr;
}
#endif
}
hostAddress.sin_port = htons(portNo);
result = bind(listenSocket, (struct sockaddr *) &hostAddress,
sizeof (hostAddress));
if (result == SOCKET_ERROR)
{
shutdownServer();
switch (socketErrno)
{
#ifdef _WINSOCKAPI_
case WSAEACCES:
return (FTALK_PORT_NO_ACCESS);
case WSAEADDRINUSE:
return (FTALK_PORT_ALREADY_BOUND);
case WSAEADDRNOTAVAIL:
default:
return (FTALK_PORT_NOT_AVAIL);
#else
case ENOTCONN: case EACCES:
return (FTALK_PORT_NO_ACCESS);
case EADDRINUSE:
return (FTALK_PORT_ALREADY_BOUND);
case EADDRNOTAVAIL:
default:
return (FTALK_PORT_NOT_AVAIL);
#endif
}
}
result = listen(listenSocket,
((MAX_CONNECTIONS < SOMAXCONN) ? MAX_CONNECTIONS : SOMAXCONN));
if (result == SOCKET_ERROR)
{
shutdownServer();
return (FTALK_LISTEN_FAILED);
}
return (FTALK_SUCCESS);
}
serverLoop()
{
int iReturnCode = (FTALK_SUCCESS);
int result;
int sockIdx;
int recvResult;
int sendResult;
fd_set fdSet;
timeval timeVal;
SOCKET maxFileDes;
int replyCnt;
int tcpOption;
if (!isStarted())
return (FTALK_ILLEGAL_STATE_ERROR);
FD_ZERO (&fdSet);
#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable: 4127)
#endif
FD_SET (listenSocket, &fdSet);
#ifdef _MSC_VER
# pragma warning(pop)
#endif
maxFileDes = listenSocket;
for (sockIdx = 0; sockIdx < MAX_CONNECTIONS; sockIdx++)
{
if (connectionSocketArr[sockIdx] != INVALID_SOCKET)
#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable: 4127)
#endif
FD_SET (connectionSocketArr[sockIdx], &fdSet);
#ifdef _MSC_VER
# pragma warning(pop)
#endif
if (connectionSocketArr[sockIdx] > maxFileDes)
maxFileDes = connectionSocketArr[sockIdx];
}
timeVal.tv_sec = (long) timeOut / 1000L;
timeVal.tv_usec = ((long) timeOut % 1000L) * 1000L;
if (timeOut == 0)
result = select((int) maxFileDes + 1, &fdSet, NULL, NULL, NULL);
else
result = select((int) maxFileDes + 1, &fdSet, NULL, NULL, &timeVal);
if (result == SOCKET_ERROR)
return (FTALK_FILEDES_EXCEEDED);
if (result == 0)
{
TRACELOG1("Slave poll time-out!\n");
dataTablePtr->timeOutHandler();
iReturnCode = (FTALK_REPLY_TIMEOUT_ERROR);
}
if (FD_ISSET (listenSocket, &fdSet))
{
for (sockIdx = 0; sockIdx < MAX_CONNECTIONS; sockIdx++)
{
if (connectionSocketArr[sockIdx] == INVALID_SOCKET)
{
struct sockaddr_in peerAddr;
SOCK_LEN_TYPE peerAddrLen = sizeof(peerAddr);
connectionSocketArr[sockIdx] = accept(listenSocket,
(struct sockaddr *) &peerAddr,
&peerAddrLen);
if (connectionSocketArr[sockIdx] != INVALID_SOCKET)
{
if (!dataTablePtr->validateMasterIpAddr(inet_ntoa(peerAddr.sin_addr)))
{
shutdown(connectionSocketArr[sockIdx], SD_BOTH);
closesocket(connectionSocketArr[sockIdx]);
connectionSocketArr[sockIdx] = INVALID_SOCKET;
TRACELOG2("Connection rejected on slot %d\n", sockIdx);
}
#ifdef TCP_NODELAY
tcpOption = 1; setsockopt(connectionSocketArr[sockIdx],
IPPROTO_TCP, TCP_NODELAY,
(char *) &tcpOption, sizeof (tcpOption));
#endif
#ifdef SO_SNDBUF
tcpOption = MAX_MSG_SIZE;
setsockopt(connectionSocketArr[sockIdx],
SOL_SOCKET, SO_SNDBUF,
(char *) &tcpOption, sizeof (tcpOption));
#endif
#ifdef SO_RCVBUF
tcpOption = MAX_MSG_SIZE;
setsockopt(connectionSocketArr[sockIdx],
SOL_SOCKET, SO_RCVBUF,
(char *) &tcpOption, sizeof (tcpOption));
#endif
#ifdef SO_LINGER
tcpOption = 0; setsockopt(connectionSocketArr[sockIdx],
SOL_SOCKET, SO_LINGER,
(char *) &tcpOption, sizeof (tcpOption));
#endif
TRACELOG2("Connection accepted on slot %d\n", sockIdx);
}
break; }
}
}
for (sockIdx = 0; sockIdx < MAX_CONNECTIONS; sockIdx++)
{
if (connectionSocketArr[sockIdx] != INVALID_SOCKET)
{
if (FD_ISSET (connectionSocketArr[sockIdx], &fdSet))
{
recvResult = recv (connectionSocketArr[sockIdx],
(char *) bufferArr, sizeof (bufferArr), 0);
sendResult = 0;
replyCnt = 0;
if (recvResult >= PREFIX_LEN) {
short dataLen;
dataLen = (short) ((bufferArr[4] << 8) | (bufferArr[5] & 0xFF));
if ((dataLen + PREFIX_LEN) == recvResult)
{
replyCnt = processMessage(&bufferArr[PREFIX_LEN],
recvResult - PREFIX_LEN);
bufferArr[2] = 0; bufferArr[3] = 0; bufferArr[4] = (char) ((replyCnt) >> 8);
bufferArr[5] = (char) ((replyCnt) & 0xFF);
sendResult = send(connectionSocketArr[sockIdx],
(char *) bufferArr,
replyCnt + PREFIX_LEN, 0);
}
}
if ((recvResult < PREFIX_LEN) ||
(sendResult != replyCnt + PREFIX_LEN))
{
shutdown(connectionSocketArr[sockIdx], SD_BOTH);
closesocket(connectionSocketArr[sockIdx]);
connectionSocketArr[sockIdx] = INVALID_SOCKET;
if (recvResult == 0)
TRACELOG2("Disconnected slot %d nicely by other peer.\n",
sockIdx);
else
TRACELOG2("Forced disconnection on slot %d!\n", sockIdx);
}
}
}
}
return iReturnCode;
}
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