Active discovery lets us introspect the state of the network stack precisely
enough that it's unnecessary, and dropping the initial DERP packets greatly
slows down tests. Additionally, it's unrealistic since our production network
will never deliver _only_ discovery packets, it'll be all or nothing.
Signed-off-by: David Anderson <danderson@tailscale.com>
For various reasons (mostly during rollouts or config changes on our
side), nodes may end up connecting to a fallback DERP node in a
region, rather than the primary one we tell them about in the DERP
map.
Connecting to the "wrong" node is fine, but it's in our best interest
for all nodes in a domain to connect to the same node, to reduce
intra-region packet forwarding.
This adds a privileged frame type used by the control system that can
kick off a client connection when they're connected to the wrong node
in a region. Then they hopefully reconnect immediately to the correct
location. (If not, we can leave them alone and stop closing them.)
Updates tailscale/corp#372
This lets a trusted DERP client that knows a pre-shared key subscribe
to the connection list. Upon subscribing, they get the current set
of connected public keys, and then all changes over time.
This lets a set of DERP server peers within a region all stay connected to
each other and know which clients are connected to which nodes.
Updates #388
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
When unregistering a replaced client connection, move the
still-connected peers to the current client connecition. Inform
the peers that we've gone only when unregistering the active
client connection.
Signed-off-by: Dmitry Adamushko <da@stablebits.net>
I saw a test flake due to the sender goroutine logging (ultimately to
t.Logf) after the server was closed.
This makes sure the all goroutines are cleaned up before Server.Close
returns.
This is mostly prep for a few future CLs, making sure we always have a
close-on-dead done channel available to select on when doing other
channel operations.
This avoids the server blocking on misbehaving or heavily contended
clients. We attempt to drop from the head of the queue to keep
overall queueing time lower.
Also:
- fixes server->client keepalives, which weren't happening.
- removes read rate-limiter, deferring instead to kernel-level
global limiter/fair queuer.
Signed-off-by: David Anderson <dave@natulte.net>
If Alice attempts to send a packet to Bob and the DERP server
encounters an error on the socket to Bob, we should not disconnect
Alice for that.
Signed-off-by: David Crawshaw <crawshaw@tailscale.com>
I broke an invariant in 11048b8932 (it was even nicely
documented then).
Also clean up the test a bit from while I was debugging it.
Fixes#84
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
