source: liacs/net/as3/src/echod/echod.c

/*  Netlab 2009 - group 1 - assignment 3
 *  Johan IJsveld
 *  Rick van der Zwet
 */
#include <sys/types.h>
#include <netdb.h>
#include <sysexits.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <sys/socket.h>
#include <netinet/ip.h> 
#include <netinet/tcp.h>

#define LISTEN_BACKLOG 0
#define BUF_SIZE 1000


#include <signal.h>


int main() {
  int conn_fd;
  char buf[BUF_SIZE];
  ssize_t recv_size;
  int retno;

  /* Create a tcp/ip socket */
  int mysocket = socket(PF_INET, SOCK_STREAM, 0);
  
  struct sockaddr_in my_addr;
  struct sockaddr_in their_addr;
  int sin_size;

  
  // ip(7) Create listen port, NOTE addresses in byte-order BYTEORDER(3)
  my_addr.sin_family = AF_INET; // By default
  my_addr.sin_port  = htons(12345);
  my_addr.sin_addr.s_addr  = htonl(INADDR_ANY);
  memset(my_addr.sin_zero, '\0', sizeof my_addr.sin_zero);

  // get connected
  retno = bind(mysocket, (struct sockaddr *) &my_addr, sizeof(struct sockaddr_in));
  retno = listen(mysocket, LISTEN_BACKLOG);
  sin_size = sizeof(struct sockaddr_in);

  // Make it a server, e.g. never ending
  while(1) {
    conn_fd = accept(mysocket, (struct sockaddr *)&their_addr, &sin_size);
    if (fork() == 0) {
      // child will help to echo the stuff
      while(1) {
      retno = recv(conn_fd, &buf, BUF_SIZE, 0);
      printf("%s\n", buf);
      if (retno <= 0)
        break; 
      retno = send(conn_fd, &buf, retno, 0);
      if (retno <= 0)
        break; 
      }
      close(conn_fd);
    }
  }
  close(mysocket);
  

return EX_OK;
}