Sadly the size of these can only be determined by parsing the entire packet.
It looks like this:
1 1 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | | QName / / +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QType | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QClass | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+