/*              \                  /
 *     _________))                ((__________
 *    /.-------./\\    \    /    //\.--------.\
 *   //#######//##\\   ))  ((   //##\\########\\
 *  //#######//###((  ((    ))  ))###\\########\\
 * ((#######((#####\\  \\  //  //#####))########))
 *  \##' `###\######\\  \)(/  //######/####' `##/
 *   )'    ``#)'  `##\`->xx<-'/##'  `(#''     `(
 *           (       ``\`..'/''       )
 *                      \""(
 *                       `- )
 *     pscan v2.0        / /       by oz0ne
 *                      ( /\
 *                      /\| \
 *                     (  \
 *                         )
 *                        /
 *                       (
 *               oz0ne7@hushmail.com
 *
 * 
 * pscan is a basic port scanner that prints the number
 * of each open port (within specified range) on the target host. 
 * It can take an ip address or a domain name as its argument.
 *
 * compile: gcc pscan2.c -o pscan
 * usage: ./pscan <ipnumber> | <domainname>
 *
 * Warning: scanning unauthorized hosts is illegal.
 * I take no responsibility for what you choose to do with this tool.
 * This code is free and without warranty
 *
*/

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

#define START_PORT 1
#define END_PORT 1024

void quit(int);
int usage(char *);

int main(int argc, char *argv[])
{
  char *host, **names, **addrs;
  struct hostent *hostinfo;
  struct sockaddr_in address;
  int port, sockfd, len, result;

  struct sigaction act;
  act.sa_handler = quit;
  sigemptyset(&act.sa_mask);
  act.sa_flags = 0;
  sigaction(SIGINT, &act, 0);

  if (argc == 1) {
    usage(argv[0]);
    exit(EXIT_FAILURE);
  }

  else { host = argv[1]; }

  hostinfo = gethostbyname(host);
  if (!hostinfo) {
    fprintf(stderr, "Error: cannot get info for host: %s:\n", host);
    exit(EXIT_FAILURE);
  }

  printf("Results for %s\n", host);
  printf("Name: %s\n", hostinfo -> h_name);
  printf("Aliases:");
  while(*names) {
    printf("%s ", **names);
    names++;
  }
  printf("\n");

  if(hostinfo -> h_addrtype != AF_INET) {
    fprintf(stderr, "Error: Not an IP host!\n");
    exit(EXIT_FAILURE);
  }

  addrs = hostinfo -> h_addr_list;
  while (*addrs) {
    printf(" %s", inet_ntoa(*(struct in_addr *)*addrs));
    addrs++;
  }

  printf("\n");
  printf("Scanning ports %d - %d\n", START_PORT, END_PORT);
  printf("Open ports:\n");

  port = START_PORT;
  while ( port <= END_PORT ) {

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    address.sin_family = AF_INET;
    address.sin_port = htons(port);
    address.sin_addr = *(struct in_addr *)*hostinfo -> h_addr_list;
    len = sizeof(address);

    result = connect(sockfd, (struct sockaddr *)&address, len);

    if (result == -1) { port++; }

    else {
      printf("%d\n", port);
      port++;
    }

    close(sockfd);
  }

  printf("Done.\n");
  exit(EXIT_SUCCESS);
}

void quit(int sig) {
  printf("Process Interupted!!\n");
  printf("Done.\n");
  exit(EXIT_FAILURE);
}

int usage(char *name) {
  printf("pscan v2.0 by oz0ne (oz0ne7@hushmail.com)\n");
  printf("Usage: %s <ipaddress> | <domainname>\n", name);
  return(1);
}