CODEWITHSUNDEEP
csocketsserverclient
M. Dennis
M. Dennis

Reputation: 53

Can only connect to Server once with Client in c

I'm writing in C and creating a Server that receives connections from multiple different Clients one at a time. However, after the first connection closes, the server can't be connected to again.

server.c:

#include <stdio.h>
#include <stdlib.h>

#include <sys/socket.h>
#include <sys/types.h>

#include <netinet/in.h>
#include <unistd.h>

int main() {
 while(1) {
  char server_message[256] = "You have reached the server!";

  //Create a socket
  int server_socket;
  server_socket = socket(AF_INET, SOCK_STREAM, 0);

  //Define the server address
  struct sockaddr_in server_address;
  server_address.sin_family = AF_INET;
  server_address.sin_port = htons(9002);
  server_address.sin_addr.s_addr = INADDR_ANY;

  //Bind the socket to the IP and port
  bind(server_socket, (struct sockaddr *) &server_address, 
  sizeof(server_address));

  //Listen for connections
  listen(server_socket, 5);

  //Accept the connection
  int client_socket = accept(server_socket, NULL, NULL);

  //Send message
  send(client_socket, server_message, sizeof(server_message), 0);

  //Close the socket
  close(server_socket);
  }
 return 0;
}

Upvotes: 3

Views: 597

Answers (2)

Iman.B
Iman.B

Reputation: 68

Change the code like this(omitted error checking):

int main() {

  //Create a socket
  int server_socket;
  server_socket = socket(AF_INET, SOCK_STREAM, 0);

  //Define the server address
  struct sockaddr_in server_address;
  server_address.sin_family = AF_INET;
  server_address.sin_port = htons(9002);
  server_address.sin_addr.s_addr = INADDR_ANY;

  //Bind the socket to the IP and port
  bind(server_socket, (struct sockaddr *) &server_address, 
  sizeof(server_address));

  //Listen for connections
  listen(server_socket, 5);

 while(1) {
  char server_message[256] = "You have reached the server!";

   //Accept the connection
   int client_socket = accept(server_socket, NULL, NULL);
   /*check some condition to exit from loop*/

   /*or send client to another thread for parallel programing*/

   //Send message
   send(client_socket, server_message, sizeof(server_message), 0);

   //Close the client socket
   close(client_socket);
  }

  close(server_socket);

 return 0;
}

in this code server after get client must wait the client finished it's job and then try to accept new client, if you want parallel, accept client and data transfer in client, it's better to put client send and receive in another thread.

Upvotes: 0

user207421
user207421

Reputation: 310909

You're looping creating a server socket, accepting one connection, processing it, and then closing your server socket. The last action will throw away all pending connections. Your loop should start immediately after the listen() call and terminate after closing the client socket, and before closing the server socket.

You are also ignoring all errors on socket(), bind(), listen(), accept(), send(), and close(). Don't do that.

Upvotes: 2

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