#include <stdio.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netdb.h>
#define SA      struct sockaddr

main(int argc, char **argv)
{
   int             sd, psd;
   struct sockaddr_in server;
   struct sockaddr_in from;
   int             fromlen;
   int             length;
   int             pn;
   int             childpid;
   int             index = 0;

   server.sin_family = AF_INET;
   server.sin_addr.s_addr = htonl(INADDR_ANY);
   server.sin_port = htons(0);

   sd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

   if (bind(sd, (SA *) & server, sizeof(server)) < 0) {
      close(sd);
      perror("binding name to stream socket");
      exit(-1);
   }
   length = sizeof(server);
   if (getsockname(sd, (SA *) & server, &length)) {
      perror("getting socket name");
      exit(0);
   }
   printf("Server Port is: %d\n\n", ntohs(server.sin_port));

   listen(sd, 4);
   fromlen = sizeof(from);
   psd = accept(sd, (SA *) & from, &fromlen);
   close(sd);
   for (index = 1; index < 4; index++) {
      childpid = fork();
      if (childpid == 0)
         EchoServe(psd, from, index);
      else
         printf("Process %d pid is %d\n", index, childpid);
   }
   wait();
}

EchoServe(psd, from, id)
   int             psd;
   struct sockaddr_in from;
   int             id;
{
   char            buf[512];
   int             rc;

   for (;;) {
      if ((rc = recv(psd, buf, sizeof(buf), MSG_PEEK)) < 0) {
         perror("peeking stream  message");
         exit(-1);
      }
      if (rc > 0) {
         buf[rc] = NULL;
         printf("Process %d Peeked: %s", id, buf);
         if ((rc = recv(psd, buf, sizeof(buf), 0)) < 0) {
            perror("consume stream  message");
            exit(-1);
         }
         buf[rc] = NULL;
         printf(">> Process %d Consummed: %s\n", id, buf);
         if (send(psd, buf, rc, 0) < 0)
            perror("sending stream message");
      } else {
         printf("Disconnected..\n");
         exit(0);
      }
   }
}