#!/usr/bin/perl
# name:    Ping Scan
# author:  Matt Rankin
# purpose: Scans IP subnets for reachable hosts because I forgot to check
#          http://netflow.latrobe.edu.au/ before going home for the weekend
#          to find hosts for the City Campus.
# details: pings a single IP address or scans from x.x.x.1-254 in random order
#          and suppresses output of failed pings. On successful ping, it then
#          attempts a ping -R and finally a traceroute. If all succeed, pscan
#          writes the output and exits.
# usage:   pscan {ip} 

my $ip = shift;
my @range = ( 1 .. 254 );

if( $ip =~ m/^(:?\d{1,3}\.){2}\d{1,3}$/ ){
   &ping( $ip, \@range ) while( @range );
}elsif( $ip =~ m/^(:?\d{1,3}\.){3}\d{1,3}$/ ){
   &ping( $ip );
}else{
   print( STDERR "You did it wrong!\n" );
   exit( 1 );
}
exit( 0 );

# =============================== subroutines ================================

sub ping( $$ ){
   my $addr = shift; 
   if( @_ ){
      my $range = shift;
      my $index = int( rand( scalar( @$range ) -1 ) );
      $addr .= '.' . splice( @$range, $index, 1 );
   }
   print( STDERR "Pinging $addr ");
   if( defined $range ){
      print( STDERR scalar( @$range ) . " remaining ) " );
   }
   my $result;
   my @output = `ping -c 1 $addr`;
   unless( &fail( \@output ) ){
      print( STDERR "." );
      $result = join( '', @output ) . "\n";
      @output = `ping -R -c 1 $addr`;
      unless( &fail( \@output ) ){
         print( STDERR "." );
         $result .= join( '', @output ) . "\n";
         @output = `traceroute -m 20 -w 2 $addr`;
         unless( &fail( \@output ) ){
            print( STDERR "Success!\n" );
            $result .= join( '', @output );
            print( $result );
            exit( 0 );
         } else { print( STDERR "\n" ); }
      } else { print( STDERR "\n" ); }
   } else { print( STDERR "\n" ); }
   sleep( 1 ) if( defined $range );
}

sub fail( $ ){
   my $str = shift;
   foreach( @$str ){
      return 1 if( m/(:?100% packet loss)|(:?wrong total length)|(:?\* \* \*)/i );
   }
}