TCP socket connection fail when webserver is active

[michelekorell]

Hello

Now i'm using mqx 4_0_2, with cw10.4. When i try to connect with a PC to the tcp socket on a twr-k60f120m with a webserver active the connection works only the half of the time. When i deactivate the embedded webserver it's work great.

I have searched on differents discussion on this forum and after trying to augment the tcp socket connection limits the problem doesn't disappear.

Here is the code that get the incoming socket connection:

//Block here until they are socket activity
sockSet[0] = mySocket->listenSock;
sockSet[1] = mySocket->sock;
sock = RTCS_selectset(sockSet, 2, 0);

if(sock ==mySocket->listenSock)
{
 ...
 //Test incoming connection
 if(mySocket->sock == 0)
 {
  mySocket->sock = accept(mySocket->listenSock, &mySocket->remoteAddr, &mySocket->remoteAddrLen);
  ...
}
...
}

I don't know if they are any error in these connection logic or if are something to activate in the user_config to run the webserver and a socket connection together.

UPDATE:

When the connection doesn't work, in the RTCS socket summary i see that my socket is connected and it appear a socket with ground state. When the task work well, the socket in ground state doesn't appear.

Any one can help me?

Thanks

[michelekorell · Accepted solution]

Workaround found:

when i wait for activity and my socket is not connected I call the accept() function that block until the connection of a client. Then I wait on RTCS_selectset() to get activity on my target socket. When socket is closed I return on accept() function. If new activity on listen socket is detected i do nothing.

if(mySocket->socket == 0)
{
     mySocket->sock = accept(mySocket->listenSock, &mySocket->remoteAddr, &mySocket->remoteAddrLen); 
...
}

...

sock = RTCS_selectset(sockSet, 2, 0);

if(sock == mySocket->sock)
{
     length = recv(sock, mySocket->receiveBuffer, mySocket->receiveBufferSize, 0);
...
}
else if(sock == RTCS_SOCKET_ERROR)
{
//Handle error
...
}
else
{
//Handle other socket activity
}

[Martin_]

From your description, it seems like accept() creates a new socket OK, but subsequent processing leads to an error. Accept() may return RTCS_SOCKET_ERROR and then you can call RTCS_geterror() on the listening socket to determine the cause. Errors are listed in rtcs_err.h.

[michelekorell]

Hello, thanks for the quick reply.

I have added somes debug message and I notice that when the connection doesnt work, the task is blocked into the accept(...).

here are the complete code of accept function:

if (mySocket->sock == 0)
{
  printf("\nAccept new socket\n");
  mySocket->sock = accept(mySocket->listenSock, &mySocket->remoteAddr, &mySocket->remoteAddrLen);
  printf("\nAccept new socket on: %d\n",mySocket->sock);

  if (mySocket->sock == RTCS_SOCKET_ERROR)
  {
    printf("\naccept() failed, error 0x%lx", RTCS_geterror(mySocket->listenSock));
    if (shutdown(mySocket->sock, FLAG_CLOSE_TX) != RTCS_OK)
    {
      printf("\nfailed shutdown socket (sock == 0)"); //, buf);
    }
    else
    {
      printf("\nDISCONNECTED");
      mySocket->sock = 0;
    }
    //continue;
  }
  // Send back a quote:
  printf("\nCONNECTED");
}

If the client disconnect and connect the task continue to work. Now I try to debug around the task execution.