controlknobs

Documentation

Overview

Package controlknobs contains client options configurable from control which can be turned on or off. The ability to turn options on and off is for incrementally adding features in.

Index

• type Knobs
  • func (k *Knobs) AsDebugJSON() map[string]any
  • func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap)

Types

type Knobs

type Knobs struct {
	// DisableUPnP indicates whether to attempt UPnP mapping.
	DisableUPnP atomic.Bool

	// KeepFullWGConfig is whether we should disable the lazy wireguard
	// programming and instead give WireGuard the full netmap always, even for
	// idle peers.
	KeepFullWGConfig atomic.Bool

	// RandomizeClientPort is whether control says we should randomize
	// the client port.
	RandomizeClientPort atomic.Bool

	// OneCGNAT is whether the the node should make one big CGNAT route
	// in the OS rather than one /32 per peer.
	OneCGNAT syncs.AtomicValue[opt.Bool]

	// ForceBackgroundSTUN forces netcheck STUN queries to keep
	// running in magicsock, even when idle.
	ForceBackgroundSTUN atomic.Bool

	// DisableDeltaUpdates is whether the node should not process
	// incremental (delta) netmap updates and should treat all netmap
	// changes as "full" ones as tailscaled did in 1.48.x and earlier.
	DisableDeltaUpdates atomic.Bool

	// PeerMTUEnable is whether the node should do peer path MTU discovery.
	PeerMTUEnable atomic.Bool

	// DisableDNSForwarderTCPRetries is whether the DNS forwarder should
	// skip retrying truncated queries over TCP.
	DisableDNSForwarderTCPRetries atomic.Bool

	// SilentDisco is whether the node should suppress disco heartbeats to its
	// peers.
	SilentDisco atomic.Bool

	// LinuxForceIPTables is whether the node should use iptables for Linux
	// netfiltering, unless overridden by the user.
	LinuxForceIPTables atomic.Bool

	// LinuxForceNfTables is whether the node should use nftables for Linux
	// netfiltering, unless overridden by the user.
	LinuxForceNfTables atomic.Bool

	// SeamlessKeyRenewal is whether to enable the alpha functionality of
	// renewing node keys without breaking connections.
	// http://go/seamless-key-renewal
	SeamlessKeyRenewal atomic.Bool

	// ProbeUDPLifetime is whether the node should probe UDP path lifetime on
	// the tail end of an active direct connection in magicsock.
	ProbeUDPLifetime atomic.Bool

	// AppCStoreRoutes is whether the node should store RouteInfo to StateStore
	// if it's an app connector.
	AppCStoreRoutes atomic.Bool

	// UserDialUseRoutes is whether tsdial.Dialer.UserDial should use routes to determine
	// how to dial the destination address. When true, it also makes the DNS forwarder
	// use UserDial instead of SystemDial when dialing resolvers.
	UserDialUseRoutes atomic.Bool

	// DisableSplitDNSWhenNoCustomResolvers indicates that the node's DNS manager
	// should not adopt a split DNS configuration even though the Config of the
	// resolver only contains routes that do not specify custom resolver(s), hence
	// all DNS queries can be safely sent to the upstream DNS resolver and the
	// node's DNS forwarder doesn't need to handle all DNS traffic.
	// This is for now (2024-06-06) an iOS-specific battery life optimization,
	// and this knob allows us to disable the optimization remotely if needed.
	DisableSplitDNSWhenNoCustomResolvers atomic.Bool

	// DisableLocalDNSOverrideViaNRPT indicates that the node's DNS manager should not
	// create a default (catch-all) Windows NRPT rule when "Override local DNS" is enabled.
	// Without this rule, Windows 8.1 and newer devices issue parallel DNS requests to DNS servers
	// associated with all network adapters, even when "Override local DNS" is enabled and/or
	// a Mullvad exit node is being used, resulting in DNS leaks.
	// We began creating this rule on 2024-06-14, and this knob
	// allows us to disable the new behavior remotely if needed.
	DisableLocalDNSOverrideViaNRPT atomic.Bool

	// DisableCryptorouting indicates that the node should not use the
	// magicsock crypto routing feature.
	DisableCryptorouting atomic.Bool

	// DisableCaptivePortalDetection is whether the node should not perform captive portal detection
	// automatically when the network state changes.
	DisableCaptivePortalDetection atomic.Bool
}

Knobs is the set of knobs that the control plane's coordination server can adjust at runtime.

func (*Knobs) AsDebugJSON

func (k *Knobs) AsDebugJSON() map[string]any

AsDebugJSON returns k as something that can be marshalled with json.Marshal for debug.

func (*Knobs) UpdateFromNodeAttributes

func (k *Knobs) UpdateFromNodeAttributes(capMap tailcfg.NodeCapMap)

UpdateFromNodeAttributes updates k (if non-nil) based on the provided self node attributes (Node.Capabilities).