When an agent receives a node, it responds with an ACK which is relayed
to the client. After the client receives the ACK, it's allowed to begin
pinging.
Fixes 2 related issues:
1. wsconncache had incorrect logic to test whether to send DERPMap updates, sending if the maps were equivalent, instead of if they were _not equivalent_.
2. configmaps used a bugged check to test equality between DERPMaps, since it contains a map and the map entries are serialized in random order. Instead, we avoid comparing the protobufs and instead depend on the existing function that compares `tailcfg.DERPMap`. This also has the effect of reducing the number of times we convert to and from protobuf.
fixes#10531
Adds a check for `version` on connection to the Agent API websocket endpoint. This is primarily for future-proofing, so that up-level agents get a sensible error if they connect to a back-level Coderd.
It also refactors the location of the `CurrentVersion` variables, to be part of the `proto` packages, since the versions refer to the APIs defined therein.
Refactors our DRPC service definitions slightly.
In the previous version, I inserted the RPCs from the tailnet proto directly into the Agent service. This makes things hard to deal with because DRPC then generates a new set of methods with new interfaces with the `DRPCAgent_` prefixed. Since you can't have a single method that takes different argument types, we couldn't reuse the implementation of those RFCs without a lot of extra classes and pass-thru methods.
Instead, the "right" way to do it is to integrate at the DRPC layer. So, we have two DRPC services available over the Agent websocket, and register them both on the DRPC `mux`.
Since the tailnet proto RPC service is now for both clients and agents, I renamed some things to clarify and shorten.
This PR also removes the `TailnetAPI` implementation from the `agentapi` package, and the next PR in the stack replaces it with the implementation from the `tailnet` package.
re: #10528
Refactors PG Coordinator to work with the Tailnet v2 API, including wrappers for the existing v1 API.
The debug endpoint functions, but doesn't return sensible data, that will be in another stacked PR.
Kayla Washburn-Love
Colin Adler
Cian Johnston
Spike Curtis
Dean Sheather