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.
Beginnings of a solution to #12297
Doesn't cover disco or definitively display whether we successfully connected to DERP, but shows some checklist diagnostics for connecting to an agent.
For this first PR, I just added it to `coder ping` to see how we like it, but could be incorporated into `coder ssh` _et al._ after a timeout.
```
$ coder ping dogfood2
p2p connection established in 147ms
pong from dogfood2 p2p via 95.217.xxx.yyy:42631 in 147ms
pong from dogfood2 p2p via 95.217.xxx.yyy:42631 in 140ms
pong from dogfood2 p2p via 95.217.xxx.yyy:42631 in 140ms
✔ preferred DERP region 999 (Council Bluffs, Iowa)
✔ sent local data to Coder networking coodinator
✔ received remote agent data from Coder networking coordinator
preferred DERP 10013 (Europe Fly.io (Paris))
endpoints: 95.217.xxx.yyy:42631, 95.217.xxx.yyy:37576, 172.17.0.1:37576, 172.20.0.10:37576
✔ Wireguard handshake 11s ago
```
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.
adds setAllPeersLost to the configMaps subcomponent of tailnet.Conn --- we'll call this when we disconnect from a coordinator so we'll eventually clean up peers if they disconnect while we are retrying the coordinator connection (or we don't succeed in reconnecting to the coordinator).
Adds a nodeUpdater component, which serves a similar role to configMaps, but tracks information from tailscale going out to the coordinator as node updates. This first PR just handles netInfo, subsequent PRs will
handle DERP forced websockets, endpoints, and addresses.
Work in progress on a subcomponent of the Conn which will handle configuring the wireguard engine on changes. I've implemented setAddresses as the simplest case and added unit tests of the reconfiguration loop.
Besides making the code easier to test and understand, the goal is for this component to handle disconnect and loss updates about peers, and thereby, implement the v2 Tailnet API.
Further PRs will handle peer updates, status updates, and net info updates.
Then, after the subcomponent is implemented and tested, I will refactor Conn to use it instead of the current monolithic architecture.
Colin Adler
Spike Curtis