# Supports ranges in any number of bytes.

sub parse_ip_mask {
   my ($ip_mask) = @_;
   my @checks;
   foreach (split(/\./, $ip_mask)) {
      if (/\[(\d+)-(\d+)\]/) {
         push(@checks, [ 0+$1, 0+$2 ]);
      } else {
         push(@checks, [ 0+$_, 0+$_ ]);
      }
   }
   return \@checks;
}

sub ip_check {
   my ($ip, $checks) = @_;
   my @ip = split(/\./, $ip);
   my $i;
   for ($i=0; $i<4; $i++) {
      return undef if ($ip[$i] < $checks->[$i][0]);
      return undef if ($ip[$i] > $checks->[$i][1]);
   }
   return 1;
}