commit 7e93ce5a766064e8dd4fa247ca0cce225bfd9940
author Suharsh Sivakumar <suharshs@google.com> Thu May 07 17:46:13 2015 -0700
committer Suharsh Sivakumar <suharshs@google.com> Thu May 07 17:46:15 2015 -0700
tree 797c47bc539096ac1e813b30bcd41da6d1b6c1a3
parent fe9b3e9447c5f3d1a9c337d9ebc3bb2e85de8fb2

ref: Add resolver to rpc.RegisterProtocol.

When dialing some of our protocols we get a net.Conn with a different
(protocol,address) pair than what we asked for. E.g. anything that
does DNS resolution will convert the host portion of the address into
an IP address.

This is annoying, because many times we want to use the (protocol,address)
pair as a cache key; i.e. it's used as a VIF cache key. Since the resolved
(protocol,address) is only available after calling the dialer, we
currently waste resources by actually dialing the address, only to
discover the resolved address is already in our cache, and closing the
dialed connection.

This change introduces a Resolver func to rpc.RegisterProtocol that can
be used to perform the DNS lookup without creating a real connection.
For protocols that do not have a resolution step, it is just the identity
function.

closes vanadium/issues#431

MultiPart: 2/2

Change-Id: If9c0de686ea89598fb424fa0f09de91c320a1161