validate_response(
resp,id,qname,qtype,sent_0x20_name) ->ok,err
Validate a decoded DNS response against the original query
Checks that the response matches the query we sent: ID match, a question
section with matching qtype and name. If sent_0x20_name is non-nil,
the response name is verified against the 0x20-encoded original
(case-preserving); otherwise a case-insensitive name comparison is used.