Parsing truncated DNS responses can produce 3 different errors

[saethlin]

There are apparently DNS servers which return responses that are truncated, but do not set the truncated bit. This results in one of these three errors, depending on where the truncation occurs:

ProtoError { kind: Msg("rdata length too large for remaining bytes, need: 46 remain: 2") }
ProtoError { kind: Message("buffer exhausted") }
ProtoError { kind: Message("unexpected end of input reached") }

It would be nice if these were all the same type so that software could react to this situation. Unfortunately I don't know that this is visible in the resolver, and I haven't (yet?) noticed any such responses coming from public DNS servers.

[bluejekyll]

Is this related at all to your testing? #1384

[saethlin]

I don't think it's related. Our application in this case is purely passive; we're trying trying to parse DNS traffic which is observed by a network sensor, and not necessarily produced by trust-dns.