serv.c

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

/* portul folosit */
#define PORT 2021

/* codul de eroare returnat de anumite apeluri */
extern int errno;

int main ()
{
  struct sockaddr_in server;    // structura folosita de server
  struct sockaddr_in from;
  char msg[100];        //mesajul primit de la client
  char msgrasp[100]=" ";        //mesaj de raspuns pentru client
  int sd;           //descriptorul de socket

  /* crearea unui socket */
  sd = socket (AF_INET, SOCK_STREAM, 0);


  /* pregatirea structurilor de date */
  bzero (&server, sizeof (server));
  bzero (&from, sizeof (from));

  /* umplem structura folosita de server */
  /* stabilirea familiei de socket-uri */
    server.sin_family = AF_INET;
  /* acceptam orice adresa */
    server.sin_addr.s_addr = htonl (INADDR_ANY);
  /* utilizam un port utilizator */
    server.sin_port = htons (PORT);

  /* atasam socketul */
  bind (sd, (struct sockaddr *) &server, sizeof (struct sockaddr));


  /* punem serverul sa asculte daca vin clienti sa se conecteze */
  listen (sd, 5);


  /* servim in mod iterativ clientii... */
  while (1)
    {
      int client1,client2,ceva1,ceva2;
      int length = sizeof (from);

      printf ("[server]Asteptam la portul %d...\n",PORT);
      fflush (stdout);

      /* acceptam un client (stare blocanta pina la realizarea conexiunii) */
      client1 = accept (sd, (struct sockaddr *) &from, &length);
      printf ("[server] Clientul 1 conectat...\n");
      fflush (stdout);
      client2 = accept (sd, (struct sockaddr *) &from, &length);
      printf ("[server] Clientul 2 conectat...\n");
      fflush (stdout);


      /* s-a realizat conexiunea, se astepta mesajul */

      /* citirea mesajului */
      read (client1, &ceva1, sizeof(int));
            printf ("[server]Mesajul 1 a fost receptionat...%s\n", msg);
      read (client2, &ceva2, sizeof(int));

      printf ("[server]Mesajul 2 a fost receptionat...%s\n", msg);

      /* returnam mesajul clientului */
      write (client1, &ceva2, sizeof(int));
      write (client2, &ceva1, sizeof(int));

      close (client1);
      close (client2);
    }               /* while */
}               /* main */