#!/usr/bin/perl -w





use strict;


use Net::Ping;








my $source_file = (shift || "/tmp/ping_list.txt");


my $good_out = "/tmp/good_ips.txt";


my $bad_out  = "/tmp/bad_ips.txt";


my %pid_to_host;


my %host_result;


my @hosts;





$|++;





open(GOOD,">$good_out")


    or die "Cannot open output file $good_out: $!\n";


open(BAD,">$bad_out")


    or die "Cannot open output file $bad_out: $!\n";


open(IPS,"$source_file") 


    or die "Cannot open source file $source_file: $!\n";





for (<IPS>)


{


    chomp;


    s/  *//;


    s/\cM//;


    if ($_ =~ m/^\d+\.\d+\.\d+\.\d+$/) 


    {


      push(@hosts,$_);


    }


    else 


    {


      print  BAD "$_ : NOT A VALID IP ADDRESS\n";


    }


}








for (@hosts)


{


      wait_for_a_kid() if keys %pid_to_host > 50;


      if ( my $pid = fork ) {


        # parent 


        $pid_to_host{$pid} = $_;


      } else { 


        # child


        exit !ping_a_host($_);


      }


}





1 while wait_for_a_kid();


for (sort keys %host_result)


{


      print GOOD "$_\n" if ($host_result{$_});


      print BAD "$_\n" if (!$host_result{$_});


}








sub ping_a_host


{


      my $host = shift;


      my $p    = Net::Ping->new('tcp',5);


      $p->ping($host) ? 1 : 0;


}





sub wait_for_a_kid


{


      my $pid = wait;


      return 0 if $pid < 0;


      my $host = delete $pid_to_host{$pid}


        or warn("Why did I see $pid ($?)\n"), next;


      $host_result{$host} = $? ? 0 : 1;


      1;


}