sub ipto32bit {
#
# Convert a dotted quad c.d.e.f to a single unsigned 32bit number.
#
    my ($ip, $c, $d, $e, $f);
    $ip = shift;
    ($c,$d,$e,$f) = split(/\./,$ip);
    return ($c << 24) + ($d << 16) + ($e << 8) + $f;
}