dnspython and DNS over TLS

[rthalley]

dnspython should support DNS-over-TLS (TCP). It would probably also be good to support DNS over HTTPS. DNS-over-DTLS (UDP) is probably not needed at this time.

[pspacek]

FYI here is how we added DNS-over-TLS on top of existing DNS-over-TCP: https://gitlab.labs.nic.cz/knot/respdiff/blob/master/respdiff/sendrecv.py#L198

[rthalley]

Cool

[filips123]

@pspacek @rthalley Can this be added directly in DNSPython?

Support for DNS-over-TLS, DNS-over-HTTPS and DNSCrypt would be really needed and very useful.

[filips123]

I'm now working on DNS-over-HTTPS support. I will probably create PR next week.

[nicki-krizek]

Am I correct in assuming DoT/DoH support should be added to both dns.query and dns.resolver?

If so, I wonder what the proper API for dns.resolver.Resolver should look like. The current query() takes tcp as argument, but when using tls or https, there will probably be additional context needed. To me it seems like the protocol along with some context should be a separate object to future-proof any upcoming API changes in 2.0 to allow for future extension (e.g. QUIC).

[filips123]

@tomaskrizek I will create PR for DNS over HTTPS later today. Update: I created #393.

[rthalley]

This was done.