#include <stdio.h>	/* standard C i/o facilities */
#include <sys/types.h>	/* system data type definitions */
#include <sys/socket.h> /* socket specific definitions */
#include <netinet/in.h> 
#include <stdlib.h>


void echo( int sd )
{
int len;
char bufin[200],bufout[250];

   while (readline(sd,bufin,100)!=0)
     {
       printf("Received: %s\n",bufin);
       sprintf(bufout,"ECHOING: %s",bufin);
       writeline(sd,bufout);
     }
}


/* Server 

   1. crea un socket
   2. assegna un indirizzo al socket e stampa il numero di porta
   3. metti il socket in modo passivo (listen)
   4. ciclo infinito
	prendi la prossima connessione
	gestisci la connessione (fai l'echo)

*/


main()
{
  int ld,sd;
  struct sockaddr_in skaddr;
  struct sockaddr from;
  int addrlen,length;


/* crea il socket 
       IP protocol family (PF_INET) 
       TCP protocol (SOCK_STREAM)
*/
  
  if ((ld = socket( PF_INET, SOCK_STREAM, 0 )) < 0)
      {
      printf("Problem creating socket\n");
      exit(1);
    }
  
/* 
	stabilisci l'indirizzo del socket:
   address family  AF_INET
   IP address INADDR_ANY (any of our IP addresses)
   il numero di porta e' assegnato dal kernel 
*/

  skaddr.sin_family = AF_INET;
  skaddr.sin_addr.s_addr = INADDR_ANY;
  skaddr.sin_port = 0;

  if (bind(ld, (struct sockaddr *) &skaddr, sizeof(skaddr))<0)
      {
	printf("Problem connecting binding\n");
	exit(0);
      }
  
/* ricava il numero di porta e stampalo */

  length = sizeof( skaddr );
  if (getsockname(ld, (struct sockaddr *) &skaddr, &length)<0)
      {
	printf("Error getsockname\n");
	exit(1);
      }
  
  printf("The port number is %d\n",ntohs(skaddr.sin_port));


/* metti il socket in modo passivo */

  if (listen(ld,5) < 0 )
      {
	printf("Error calling listen\n");
	exit(1);
      }
  

  while (1)
      {
	addrlen=18;
	if ( (sd = accept( ld, &from, &addrlen)) < 0)
	    {
	      printf("Problem with accept call\n");
	      exit(1);
	    }

	printf("Got a connection - processing...\n");
	echo(sd);
	printf("Done with connection\n");
	close(sd);
      }
}