cmd/tailscale/cli: add basic 'down' subcommand

RELNOTE=yes

ipn/backend.go

@@ -144,6 +144,9 @@ type Backend interface {
 	// WantRunning. This may cause the wireguard engine to
 	// reconfigure or stop.
 	SetPrefs(*Prefs)
+	// SetWantRunning is like SetPrefs but sets only the
+	// WantRunning field.
+	SetWantRunning(wantRunning bool)
 	// RequestEngineStatus polls for an update from the wireguard
 	// engine. Only needed if you want to display byte
 	// counts. Connection events are emitted automatically without

ipn/fake_test.go

@@ -79,6 +79,10 @@ func (b *FakeBackend) SetPrefs(new *Prefs) {
 	}
 }
 
+func (b *FakeBackend) SetWantRunning(v bool) {
+	b.SetPrefs(&Prefs{WantRunning: v})
+}
+
 func (b *FakeBackend) RequestEngineStatus() {
 	b.notify(Notify{Engine: &EngineStatus{}})
 }

ipn/ipnstate/ipnstate.go

@@ -90,6 +90,12 @@ type StatusBuilder struct {
 	st     Status
 }
 
+func (sb *StatusBuilder) SetBackendState(v string) {
+	sb.mu.Lock()
+	defer sb.mu.Unlock()
+	sb.st.BackendState = v
+}
+
 func (sb *StatusBuilder) Status() *Status {
 	sb.mu.Lock()
 	defer sb.mu.Unlock()

ipn/local.go

@@ -144,6 +144,8 @@ func (b *LocalBackend) UpdateStatus(sb *ipnstate.StatusBuilder) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
+	sb.SetBackendState(b.state.String())
+
 	// TODO: hostinfo, and its networkinfo
 	// TODO: EngineStatus copy (and deprecate it?)
 	if b.netMap != nil {
@@ -796,6 +798,18 @@ func (b *LocalBackend) shieldsAreUp() bool {
 	return b.prefs.ShieldsUp
 }
 
+func (b *LocalBackend) SetWantRunning(wantRunning bool) {
+	b.mu.Lock()
+	new := b.prefs.Clone()
+	b.mu.Unlock()
+	if new.WantRunning == wantRunning {
+		return
+	}
+	new.WantRunning = wantRunning
+	b.logf("SetWantRunning: %v", wantRunning)
+	b.SetPrefs(new)
+}
+
 // SetPrefs saves new user preferences and propagates them throughout
 // the system. Implements Backend.
 func (b *LocalBackend) SetPrefs(new *Prefs) {

ipn/message.go

@@ -57,6 +57,7 @@ type Command struct {
 	Login                 *oauth2.Token
 	Logout                *NoArgs
 	SetPrefs              *SetPrefsArgs
+	SetWantRunning        *bool
 	RequestEngineStatus   *NoArgs
 	RequestStatus         *NoArgs
 	FakeExpireAfter       *FakeExpireAfterArgs
@@ -144,6 +145,9 @@ func (bs *BackendServer) GotCommand(cmd *Command) error {
 	} else if c := cmd.SetPrefs; c != nil {
 		bs.b.SetPrefs(c.New)
 		return nil
+	} else if c := cmd.SetWantRunning; c != nil {
+		bs.b.SetWantRunning(*c)
+		return nil
 	} else if c := cmd.RequestEngineStatus; c != nil {
 		bs.b.RequestEngineStatus()
 		return nil
@@ -266,6 +270,10 @@ func (bc *BackendClient) Ping(ip string) {
 	bc.send(Command{Ping: &PingArgs{IP: ip}})
 }
 
+func (bc *BackendClient) SetWantRunning(v bool) {
+	bc.send(Command{SetWantRunning: &v})
+}
+
 // MaxMessageSize is the maximum message size, in bytes.
 const MaxMessageSize = 10 << 20