tailscale/wgengine/magicsock/debugknobs.go

// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build !ios && !js
// +build !ios,!js

package magicsock

import (
	"tailscale.com/envknob"
)

const linkDebug = true

// Various debugging and experimental tweakables, set by environment
// variable.
var (
	// debugDisco prints verbose logs of active discovery events as
	// they happen.
	debugDisco = envknob.RegisterBool("TS_DEBUG_DISCO")
	// debugOmitLocalAddresses removes all local interface addresses
	// from magicsock's discovered local endpoints. Used in some tests.
	debugOmitLocalAddresses = envknob.RegisterBool("TS_DEBUG_OMIT_LOCAL_ADDRS")
	// debugUseDerpRoute temporarily (2020-03-22) controls whether DERP
	// reverse routing is enabled (Issue 150).
	debugUseDerpRoute = envknob.RegisterOptBool("TS_DEBUG_ENABLE_DERP_ROUTE")
	// logDerpVerbose logs all received DERP packets, including their
	// full payload.
	logDerpVerbose = envknob.RegisterBool("TS_DEBUG_DERP")
	// debugReSTUNStopOnIdle unconditionally enables the "shut down
	// STUN if magicsock is idle" behavior that normally only triggers
	// on mobile devices, lowers the shutdown interval, and logs more
	// verbosely about idle measurements.
	debugReSTUNStopOnIdle = envknob.RegisterBool("TS_DEBUG_RESTUN_STOP_ON_IDLE")
	// debugAlwaysDERP disables the use of UDP, forcing all peer communication over DERP.
	debugAlwaysDERP = envknob.RegisterBool("TS_DEBUG_ALWAYS_USE_DERP")
	// debugEnableSilentDisco disables the use of heartbeatTimer on the endpoint struct
	// and attempts to handle disco silently. See issue #540 for details.
	debugEnableSilentDisco = envknob.RegisterBool("TS_DEBUG_ENABLE_SILENT_DISCO")
)

// inTest reports whether the running program is a test that set the
// IN_TS_TEST environment variable.
//
// Unlike the other debug tweakables above, this one needs to be
// checked every time at runtime, because tests set this after program
// startup.
func inTest() bool { return envknob.Bool("IN_TS_TEST") }