response when DNS request goes to PeerAPI DoH
To support feature/conn25 and other extensions or consumers needing to
know which PeerAPI node handled a DNS request, e.g. for app connectors
or exit nodes, and needing extra data from the server that can be
transmitted in the headers.
DNS responses from other upstream resolvers do not get any metadata
populated, even if those servers are DoH.
Add a new Response type in net/dns/resolver that includes the raw
response bytes and the optional metadata, and replace the bare bytes
with it in some places.
Pass this new type to to net/dns.ResponseMapper instead of the bare
bytes to the extensions can see the metadata.
Updates tailscale/corp#46169
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
Michael Ben-Ami
de7245d25b