Add a new `--force-probe` flag to `tailscale exit-node suggest` that
waits for a routecheck.Refresh to finish before suggesting an exit
node.
This flag is currently hidden from the help text, but this flag is a
hint to the user that exit-node suggestions are based on routecheck
reachability reports.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
Now that the routecheck subsystem is continuously collecting
reachability reports in the background, we can add a hook to
LocalBackend for fetching its report. That allows
suggestExitNodeUsingTrafficSteering to consult that report when
disqualifying candidates, instead of blocking on an immediate probe.
Exit node suggestions will only consult the report when the
`client-side-reachability` and `client-side-reachability-routecheck`
node attributes are both set on the current node.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
Previously, refreshing the routecheck.Client would probe to generate a
new routecheck.Report, but this method was only wired up to the
LocalAPI and the `tailscale routecheck` command. However, waiting for
a probe to finish before choosing a router would take too long, so we
must keep a regularly updated report to be consulted as necessary.
This patch adds a Start and Close method to the routecheck.Client and
starts it in the background from features/routecheck. To enable this
feature for a given node, set both of the following node attributes:
`client-side-reachability` and `client-side-reachability-routecheck`.
This patch also wires up the RouterTracker.OnRoutersChange hook, which
fires a callback whenever a new network map includes information about
a router node, This signals to the routecheck.Client that it might
need to schedule another probe, if the shape of the routing table has
changed materially.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
This patch adds a new ipnext.NotifyWatcher interface that exposes
ipn.LocalBackend.WatchNotifications so that extensions inside
tailscaled can subscribe to the IPN bus, much like how the GUI
clients subscribe to it through the Local API.
This interface is used by the new feature/routecheck.RouterTracker to
watch for changes in the peer map that affect routers. RouterTracker
uses dead reckoning to incrementally maintain the set of routers. We
do this to avoid looping over the peer map repeatedly. See #17366.
RouterTracker supports two hooks:
- OnNetMapAvailable signals that the initial netmap has been received,
so that the routecheck.Client can wake up goroutines that are
waiting for it.
- OnRoutersChange signals that the set of routers has changed, so that
the routecheck.Client can decide to probe a subset of the routers
instead of all of them. Currently, this optimization hasn’t been
implemented yet.
Updates #17366
Updates #20062
Updates tailscale/corp#33033
Co-authored-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: Simon Law <sfllaw@tailscale.com>
This patch adds a new `client-side-reachability-routecheck` node
attribute to allow admins to selectively enable background routecheck
probing on trial nodes. The current implementation is still
experimental.
It adds the routecheck.IsEnabled helper to check for the new
`client-side-reachability-routecheck` node attribute alongside the
existing `client-side-reachability` node attribute in this node’s self
capabilities. This allows administrators to turn on and off this
feature by editing the policy file.
It adds the `TS_DEBUG_FORCE_CLIENT_SIDE_REACHABILITY_ROUTECHECK`
environment variable which can be set to override the policy file.
When set to `true`, it forcibly enables this feature. And when set to
`false`, it forcibly disables it.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
util/def: add def.Bool and def.Duration default parse helpers
Replace multiple instances of def.Bool and def.Duration with a new util/def
package.
Updates #20018
Co-authored-by: Bobby <boby@codelabs.co.id>
Co-authored-by: Simon Law <sfllaw@tailscale.com>
Signed-off-by: Bobby <boby@codelabs.co.id>
Signed-off-by: Simon Law <sfllaw@tailscale.com>
In order to support a `tailscale routecheck` command, we introduce the
`/localapi/v0/routecheck` endpoint to the local API. This endpoint
returns the most recent report collected by the routecheck client.
If `force=true` is an argument in the query string, then this endpoint
will actively probe before returning the report.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
The routecheck package parallels the netcheck package, where the
former checks routes and routers while the latter checks networks.
Like netcheck, it compiles reports for other systems to consume.
Historically, the client has never known whether a peer is actually
reachable. Most of the time this doesn’t matter, since the client will
want to establish a WireGuard tunnel to any given destination.
However, if the client needs to choose between two or more nodes,
then it should try to choose a node that it can reach.
Suggested exit nodes are one such example, where the client filters
out any nodes that aren’t connected to the control plane. Sometimes an
exit node will get disconnected from the control plane: when the
network between the two is unreliable or when the exit node is too
busy to keep its control connection alive. In these cases, Control
disables the Node.Online flag for the exit node and broadcasts this
across the tailnet. Arguably, the client should never have relied on
this flag, since it only makes sense in the admin console.
This patch implements an initial routecheck client that can probe
every node that your client knows about. You should not ping scan your
visible tailnet, this method is for debugging only.
This patch also introduces a new OnNetMapToggle hook, which fires when
the netmap transitions from nil to non-nil, or vice versa. This
happens either when the client receives its first MapResponse after
connecting to the control plane, or when it clears the netmap while it
is disconnecting. Routecheck uses this to wait for a valid netmap
so it knows which peers to probe.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
RouteCheck, which checks that overlapping routers are reachable, is
enabled by default for both tailscaled and tsnet.
Updates #17366
Updates tailscale/corp#33033
Signed-off-by: Simon Law <sfllaw@tailscale.com>
Simon LawandSimon Law
