Thread: Server socket closes after client disconnection

Hi.

I'm having this simple C code for a server and client. What server does is to send a message to the client when is connected. The thing is that when client disconnects server socket cannot accept new connection and program exits.

SERVER CODE:

Code:

  1 #include <stdlib.h>
  2 #include <stdio.h>
  3 #include <sys/types.h>
  4 #include <sys/socket.h>
  5 #include <netdb.h>
  6 #include <netinet/in.h>
  7 #include <strings.h>
  8 #include <unistd.h>
  9 #include <string.h>
 10 
 11 char MESSAGE[] = "Welcome to Server";
 12 
 13 int main(){
 14     
 15     int server_socket , server_port = 4444, client_socket;
 16     int bind_status, listen_status;
 17     struct sockaddr_in server_address,client_address; 
 18     socklen_t addr_length = sizeof(client_address);
 19 
 20     // Create the socket
 21     server_socket = socket(AF_INET, SOCK_STREAM, 0);
 22 
 23     if(!server_socket){
 24             fprintf(stderr, "[mon] Couldn't create socket\n");
 25             exit(1); 
 26     }
 27     
 28     
 29     // Setup the address structure
 30     bzero(&server_address,sizeof(server_address));
 31     server_address.sin_family = AF_INET;
 32     server_address.sin_addr.s_addr = htonl(INADDR_ANY);
 33     server_address.sin_port = htons(server_port);
 34     
 35     // Bind the socket to the specified port and address
 36     bind_status = bind(server_socket , 
 37                     (struct sockaddr *)&server_address, 
 38                     sizeof(server_address));
 39 
 40     if(bind_status != 0){
 41             fprintf(stderr, "[mon] Failed to bind the socket\n");
 42             close(server_socket);
 43             exit(1);
 44     }
 45 
 46     // Make the socket listen for connections
 47     listen_status = listen(server_socket, 5);
 48 
 49     if(listen_status == -1){
 50             fprintf(stderr, "[mon] Failed to listen\n");
 51             close(server_socket);
 52             exit(1);
 53     }
 54     
 55     while(1){
 56        
 57         bzero(&client_address,sizeof(client_address));
 58         client_socket = accept(server_socket, 
 59                         (struct sockaddr *)&server_socket, 
 60                         &addr_length);
 61 
 62         if(client_socket == -1){
 63                 fprintf(stderr, "Cannot accept connections\n");
 64                 close(server_socket);
 65                 exit(1);
 66         }
 67         
 68         printf("Waiting for clients\n");
 69         
 70         // Send the message to the client
 71         write(client_socket, MESSAGE, strlen(MESSAGE));
 72 
 73         close(client_socket);
 74     }
 75 
 76     close(server_socket);
 77 
 78     return 0;        
 79 }

CLIENT CODE

Code:

1 #include <stdlib.h>
  2 #include <stdio.h>
  3 #include <sys/types.h>
  4 #include <sys/socket.h>
  5 #include <netdb.h>
  6 #include <netinet/in.h>
  7 #include <strings.h>
  8 #include <unistd.h>
  9 #include <string.h>
 10 #include <arpa/inet.h>
 11 
 12 int main(){
 13 
 14     int client_socket , server_port = 4444;
 15     char buffer[256];
 16     struct sockaddr_in server_address ;
 17     socklen_t addr_length = sizeof(server_address);
 18     int connect_status, read_status;
 19 
 20     // Create clients socket
 21     client_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 22 
 23     if(client_socket == -1){
 24         fprintf(stderr, "[mon] Could not create client socket\n");
 25         exit(1);
 26     }
 27 
 28     // Setup the address structure
 29     bzero(&server_address,sizeof(server_address));
 30     server_address.sin_family = AF_INET;
 31     server_address.sin_addr.s_addr = inet_addr("127.0.0.1");
 32     server_address.sin_port = htons(server_port);
 33     
 34     // Connect to the server
 35     connect_status = connect(client_socket,
 36                     (struct sockaddr *)&server_address,
 37                     addr_length);
 38     
 39     if(connect_status != 0){
 40         fprintf(stderr, "[mon] Could not connect to the server\n");
 41         exit(1);
 42     }
 43 
 44     // Get the message from the server
 45     read_status = read(client_socket, buffer, sizeof(buffer));
 46 
 47     if((read_status > 0) && (read_status <= (int)sizeof(buffer)) ){
 48         // Null terminate the received buffer
 49         buffer[read_status] = 0;
 50         printf("%s\n",buffer);
 51     }else
 52         fprintf(stderr, "[mon] Nothing retrieved\n");
 53 
 54     close(client_socket);
 55 
 56     return 0;
 57 }

When I'm running them, server's console returns :

Waiting for clients
Cannot accept connections

Any idea why this is happening ?

Thank you.

You are right. That was the mistake. Thank you very much and sorry for the extra numbers. I ll take it in mind in the next post.