CallMeMaybeVia reception and endpoint allocation have been collapsed to
a single event channel. discoInfo caching for active relay handshakes
is now implemented, and the handshake implementation is starting to
take shape.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
The event loop removes the need for growing locking complexities and
synchronization. Now we simply use channels. The event loop only runs
while there is active work to do.
relayManager remains no-op inside magicsock for the time being.
endpoints are never 'relayCapable' and therefore endpoint & Conn will
not feed CallMeMaybeVia or allocation events into it.
A number of relayManager events remain unimplemented, e.g.
CallMeMaybeVia reception and relay handshaking.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
