Simon LawandGitHub
2fbd30824b
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>
93 lines
2.4 KiB
Go
93 lines
2.4 KiB
Go
// Copyright (c) Tailscale Inc & contributors
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// SPDX-License-Identifier: BSD-3-Clause
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// Package routecheck registers support for RouteCheck,
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// which checks the reachability of overlapping routers.
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//
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// When there are multiple network paths to an IP address, it is being routed by
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// overlapping routers. The client uses reachability to pick between those
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// paths: either sticking with an active WireGuard session or choosing from the
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// peers that it has determined it can reach. It doesn’t need reachability for
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// IP addresses that have only one network path, since it can naively attempt to
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// establish a WireGuard session.
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package routecheck
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import (
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"fmt"
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"tailscale.com/ipn/ipnext"
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"tailscale.com/net/routecheck"
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"tailscale.com/types/logger"
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"tailscale.com/types/netmap"
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)
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// FeatureName is the name of the feature implemented by this package.
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// It is also the [extension] name and the log prefix.
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const featureName = "routecheck"
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func init() {
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ipnext.RegisterExtension(featureName, func(logf logger.Logf, b ipnext.SafeBackend) (ipnext.Extension, error) {
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return &Extension{
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logf: logger.WithPrefix(logf, featureName+": "),
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backend: b,
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}, nil
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})
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}
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// Extension implements the [ipnext.Extension] interface.
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type Extension struct {
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Client *routecheck.Client
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logf logger.Logf
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backend ipnext.SafeBackend
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nb nodeBackender
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nm routecheck.NetMapper
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}
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var _ ipnext.Extension = new(Extension)
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// Name implements the [ipnext.Extension.Name] interface method.
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func (e *Extension) Name() string {
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return featureName
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}
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// Init implements the [ipnext.Extension.Init] interface method.
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func (e *Extension) Init(h ipnext.Host) error {
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if routecheck.DebugForceClientSideReachabilityRoutecheck().EqualBool(false) {
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return ipnext.SkipExtension
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}
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e.nb = nodeBackender{h}
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nm, ok := e.backend.(routecheck.NetMapper)
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if !ok {
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return fmt.Errorf("backend %T does not implement routecheck.NetMapper", e.backend)
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}
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e.nm = nm
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pinger := e.backend.Sys().Engine.Get()
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c, err := routecheck.NewClient(e.logf, e.nb, e.nm, pinger)
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if err != nil {
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return err
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}
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e.Client = c
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h.Hooks().OnNetMapToggle.Add(e.onNetMapToggle)
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return nil
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}
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// Shutdown implements the [ipnext.Extension.Shutdown] interface method.
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func (e *Extension) Shutdown() error {
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err := e.Client.Close()
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return err
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}
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func (e *Extension) onNetMapToggle(nm *netmap.NetworkMap) {
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if nm == nil {
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return
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}
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e.Client.NotifyNetMapAvailable(nm)
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}
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