#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>

#define MAXLINE 4096 /*max text line length*/
#define SERV_PORT 3000 /*port*/
#define LISTENQ 8 /*maximum number of client connections*/

int main (int argc, char **argv)
{
 int listenfd, connfd, n;
 pid_t childpid;
 socklen_t clilen;
 char buf[MAXLINE];
 struct sockaddr_in cliaddr, servaddr;

 //Create a socket for the soclet
 //If sockfd<0 there was an error in the creation of the socket
 if ((listenfd = socket (AF_INET, SOCK_STREAM, 0)) <0) {
  perror("Problem in creating the socket");
  exit(2);
 }


 //preparation of the socket address
 servaddr.sin_family = AF_INET;
 servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 servaddr.sin_port = htons(SERV_PORT);

 //bind the socket
 bind (listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));

 //listen to the socket by creating a connection queue, then wait for clients
 listen (listenfd, LISTENQ);

 printf("%s\n","Server running...waiting for connections.");

 for ( ; ; ) {

  clilen = sizeof(cliaddr);
  //accept a connection
  connfd = accept (listenfd, (struct sockaddr *) &cliaddr, &clilen);

  printf("%s\n","Received request...");

  if ( (childpid = fork ()) == 0 ) {//if it’s 0, it’s child process

    printf ("%s\n","Child created for dealing with client requests");

    //close listening socket
    close (listenfd);

    while ( (n = recv(connfd, buf, MAXLINE,0)) > 0)  {
      printf("%s","String received from and resent to the client:");
      puts(buf);
      send(connfd, buf, n, 0);
    }

    if (n < 0)
      printf("%s\n", "Read error");
    exit(0);
  }
 //close socket of the server
 close(connfd);
 
 }

}