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

#define START 1
#define STOP 1024

void main(int argc, char **argv)
{
  int s, port;
  struct hostent *host;
  struct sockaddr_in victim;

  printf("PortScan v1.0 - By darknite[@brigade.dhs.org]\n");
  printf("For his socket-programming article, 1998\n");
  if (argc < 2) {
    printf("Usage: %s <hostname>\n", argv[0]);
    exit(-1);
  }

  host = gethostbyname(argv[1]);
  if (!host) {
    herror(argv[1]);
    exit(-1);
  }

  victim.sin_family = AF_INET;
  victim.sin_addr.s_addr = *(long *) (host->h_addr);

  for (port = START; port <= STOP; port++) {
    victim.sin_port = htons(port);
    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s < 0) {
      printf("Error creating socket.\n");
      exit(-1);
    }

    if (!connect(s, (struct sockaddr *) &victim, sizeof(victim)))
      printf("port: %i\n", port);
    if (close(s)) {
      printf("Error closing socket.\n");
      exit(-1);
    }

  }
}