My UDP socket is bind()ing to port 53 (DNS). Does UDP have a TIME_WAIT state or is using SO_REUSEADDR pointless on UDP sockets?
UDP doesn't have connections, so there's nothing analogous to TIME_WAIT. You don't need to use SO_REUSEADDR.
If you're listening on a broadcast or multicast address, you might need to use SO_REUSEPORT, so that if there are multiple listeners on the same machine they don't conflict. However, from what I can tell, this doesn't exist on Linux.