/*
  Pscan v1.0 - Simple UNIX based TCP port scanner
  Tested on Redhat Linux 7.2
  
  ++ Scans all 65535 TCP ports on a 100 Mbps Ethernet LAN in just 15 seconds !!
  
  Compile: gcc -o Pscan Pscan.c

  (c) 2002 by Benny T. <allegro16@hotmail.com>

*/


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

void Usage();


void main(int argc,char *argv[])
{
  int i,dots=0;
  int sock,portcount;
  struct sockaddr_in sain;

  if(argc!=4) {
    Usage();
    exit(0);
  }
  for(i=0;i<strlen(argv[1]);i++) {
    if(argv[1][i]=='.') {
      dots++;
    }
  }
  if(dots!=3) {
    printf("Invalid IP address\n");
    Usage();
    exit(0); 
  }
  if(atoi(argv[2]) > 65535 || atoi(argv[3]) > 65535) {
    printf("Invalid port number\n");
    Usage();
    exit(0);
  }
  sock = socket(AF_INET,SOCK_STREAM,0);
  if(sock<0) {
    printf("Error creating socket\n");
    exit(0);
  }
  portcount = 0;
  printf("Scanning host ");
  printf(argv[1]);
  printf(".....\n\n");
  sain.sin_family=AF_INET;
  sain.sin_addr.s_addr=inet_addr((char *)argv[1]);
  for(i=atoi(argv[2]);i<=atoi(argv[3]);i++) {
    sain.sin_port=htons(i);
    if(connect(sock,(struct sockaddr *)&sain,sizeof(sain))==0) { 
      portcount++;
      printf("Port ");
      printf("%d",i);
      printf(" open\n");
      close(sock);
      sock = socket(AF_INET,SOCK_STREAM,0);
      if(sock<0) {
        printf("Error creating socket\n");
        exit(0);
      }
    }
  }
  printf("\n");
  printf("%d%s",portcount, " TCP port(s) open\n");
  close(sock);

}

void Usage() 
{
  printf("\nPscan v1.0 - Simple UNIX based TCP port scanner\n");
  printf("(c) 2002 by Benny T. <mailto:allegro16@hotmail.com>\n");
  printf("Usage: Pscan <IP address> <From port> <To port>\n\n");
}