From 95470c3448f0a9d9eb98906fe24ccc1c5df1bbab Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@tailscale.com>
Date: Thu, 1 Apr 2021 23:04:23 -0700
Subject: [PATCH] net/dns: remove Cleanup manager parameter.

It's only use to skip some optional initialization during cleanup,
but that work is very minor anyway, and about to change drastically.

Signed-off-by: David Anderson <danderson@tailscale.com>
---
 net/dns/config.go        |  3 ---
 net/dns/manager.go       |  1 -
 net/dns/manager_linux.go | 12 ++----------
 net/dns/noop.go          | 17 -----------------
 4 files changed, 2 insertions(+), 31 deletions(-)
 delete mode 100644 net/dns/noop.go

diff --git a/net/dns/config.go b/net/dns/config.go
index e89eda86e..884d9284c 100644
--- a/net/dns/config.go
+++ b/net/dns/config.go
@@ -63,7 +63,4 @@ type ManagerConfig struct {
 	Logf logger.Logf
 	// InterfaceName is the name of the interface with which DNS settings should be associated.
 	InterfaceName string
-	// Cleanup indicates that the manager is created for cleanup only.
-	// A no-op manager will be instantiated if the system needs no cleanup.
-	Cleanup bool
 }
diff --git a/net/dns/manager.go b/net/dns/manager.go
index 6e6d4cd92..60a790bb0 100644
--- a/net/dns/manager.go
+++ b/net/dns/manager.go
@@ -94,7 +94,6 @@ func Cleanup(logf logger.Logf, interfaceName string) {
 	mconfig := ManagerConfig{
 		Logf:          logf,
 		InterfaceName: interfaceName,
-		Cleanup:       true,
 	}
 	dns := NewManager(mconfig)
 	if err := dns.Down(); err != nil {
diff --git a/net/dns/manager_linux.go b/net/dns/manager_linux.go
index 6f995d4bf..51841219c 100644
--- a/net/dns/manager_linux.go
+++ b/net/dns/manager_linux.go
@@ -7,17 +7,9 @@
 func newManager(mconfig ManagerConfig) managerImpl {
 	switch {
 	case isResolvedActive():
-		if mconfig.Cleanup {
-			return newNoopManager(mconfig)
-		} else {
-			return newResolvedManager(mconfig)
-		}
+		return newResolvedManager(mconfig)
 	case isNMActive():
-		if mconfig.Cleanup {
-			return newNoopManager(mconfig)
-		} else {
-			return newNMManager(mconfig)
-		}
+		return newNMManager(mconfig)
 	case isResolvconfActive():
 		return newResolvconfManager(mconfig)
 	default:
diff --git a/net/dns/noop.go b/net/dns/noop.go
deleted file mode 100644
index 35c07a232..000000000
--- a/net/dns/noop.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright (c) 2020 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.
-
-package dns
-
-type noopManager struct{}
-
-// Up implements managerImpl.
-func (m noopManager) Up(Config) error { return nil }
-
-// Down implements managerImpl.
-func (m noopManager) Down() error { return nil }
-
-func newNoopManager(mconfig ManagerConfig) managerImpl {
-	return noopManager{}
-}