SonnyWalkman
commented
11 months ago Hello @tenkavideo and @peterkvt80
I believe the issue lies in the use of this function DieWithError in the TCPClient class immediately terminates the process upon encountering an error, as indicated by the exit(1) call.
I believe this is the reason why Vbit2 is needing a restart after an error occurs because it's dead and unable to listen and establish a new TCP connection.
A more graceful approach might be to handle the error without exiting the entire process, perhaps by issuing a command error dropping the connection. The Handler function is responsible for managing incoming client connections. It reads data from the client socket and processes it. If an the value is <= to zero during data reception (as indicated by recv()returning a negative value), signals TCP connection is disconnect followed by the offending DieWithError function is called, leading to the termination of the Vbit2 process.
Peter,
I recommend a small change to the TCPClient function to handle the error? replace the DieWithError function with a response then drop the connection avoid terminating the entire process.
This approach will enable Vbit2 to simply disconnect the connection.
What tenkavideo is alluding to is an issue with the P command which I can't help with sorry?
The command handler loop in the Handler function may need extra checks against client disconnections and errors. Add additional error handling to manage different types of exceptions or unexpected behaviours from the client side which I haven't looked into? May need to handle malformed requests?
Replace below:-
/** HandleTCPClient
* Commands come in here.
* They need to be accumulated and when we have a complete line, send it to a command interpreter.
*/
void TCPClient::Handler(int clntSocket)
{
char echoBuffer[RCVBUFSIZE]; /* Buffer for echo string */
char response[RCVBUFSIZE];
int recvMsgSize; /* Size of received message */
int i;
clearCmd();
/* Send received string and receive again until end of transmission */
for (recvMsgSize=1;recvMsgSize > 0;) /* zero indicates end of transmission */
{
/* See if there is more data to receive */
if ((recvMsgSize = recv(clntSocket, echoBuffer, RCVBUFSIZE, 0)) < 0)
**DieWithError("recv() failed");**
for (i=0;i<recvMsgSize;i++)
{
addChar(echoBuffer[i], response);
if (*response)
send(clntSocket, response, strlen(response), 0);
}
/* Echo message back to client */
//if (send(clntSocket, echoBuffer, recvMsgSize, 0) != recvMsgSize)
// DieWithError("send() failed");
}
#ifdef WIN32
closesocket(clntSocket);
#else
close(clntSocket); /* Close client socket */
#endif // WIN32
}With:
/** HandleTCPClient
* Commands come in here.
* They need to be accumulated and when we have a complete line, send it to a command interpreter.
* If the connection receives a negation or zero value with just close the socket, keep the client running. #bugfix
*/
void TCPClient::Handler(int clntSocket)
{
char echoBuffer[RCVBUFSIZE];
char response[RCVBUFSIZE];
int recvMsgSize;
clearCmd();
while (true)
{
recvMsgSize = recv(clntSocket, echoBuffer, RCVBUFSIZE, 0);
if (recvMsgSize < 0) {
// Handle the error without exiting the process
// Optionally log the error or send a message back to the client
std::cerr << "Error in receiving data." << std::endl;
break;
}
else if (recvMsgSize == 0) {
// Client has closed the connection
std::cerr << "Client has closed the connection." << std::endl;
break;
}
// Process the received data
for (int i = 0; i < recvMsgSize; i++) {
addChar(echoBuffer[i], response);
if (*response) {
send(clntSocket, response, strlen(response), 0);
}
}
}
#ifdef WIN32
closesocket(clntSocket);
#else
close(clntSocket);
#endif
}
tenkavideo
ZXGuesser
Hello, I'm encountering an issue with Ncat on Windows. Whenever I send a "P310000" command or any other page command, the vbit2 application closes the connection, and it becomes impossible to reconnect until the process is restarted tries on windows 11,telnet,ncat ,putty,windows firewall off teefax demo pages default vbit config, plus connection vars on port 5570
this vbit answer to P310000 command [TCPClient::addChar] finished cmd='7 [PageList::FindPage] Selecting 31000 thx!