#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<netdb.h>
#include<fcntl.h>

#define RPORT 30000

int main()
{
  int r;  // random number
  int rn;
  struct sockaddr_in serverinfo;
  struct sockaddr_in clientinfo;
  int sfd, cfd;   // server and client descriptors
  
  // set info for serverinfo struct
  serverinfo.sin_family = AF_INET;
  serverinfo.sin_port = htons(RPORT);
  serverinfo.sin_addr.s_addr = htonl(INADDR_ANY);  //wildcard

  sfd = socket(AF_INET,SOCK_STREAM,0);
  bind(sfd,(struct sockaddr *)&serverinfo,sizeof(serverinfo));
  listen(sfd,16);  // 16 is max size of waiting queue
  
  r = sizeof(clientinfo);
  cfd = accept(sfd,(struct sockaddr *)&clientinfo,&r);
  if (cfd<0) exit(1);

  r = 1;
  rn = htonl(r);
  write(cfd,&rn,4);
  
  close(cfd);
  close(sfd);
  exit(0);
}