cmd/tailscale,com/tailscale/ipn: implement QR sign-in for TV devices

This is a cleand up version of #27.

Fixes tailscale/tailscale#1611

Signed-off-by: Elias Naur <mail@eliasnaur.com>

android/src/main/java/com/tailscale/ipn/App.java

@@ -11,6 +11,7 @@ import android.app.Fragment;
 import android.app.FragmentTransaction;
 import android.app.NotificationChannel;
 import android.app.PendingIntent;
+import android.app.UiModeManager;
 import android.content.BroadcastReceiver;
 import android.content.ContentResolver;
 import android.content.ContentValues;
@@ -21,6 +22,7 @@ import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageInfo;
 import android.content.pm.Signature;
+import android.content.res.Configuration;
 import android.provider.MediaStore;
 import android.provider.Settings;
 import android.net.ConnectivityManager;
@@ -394,4 +396,9 @@ public class App extends Application {
 
             return sb.toString();
         }
+
+	boolean isTV() {
+		UiModeManager mm = (UiModeManager)getSystemService(UI_MODE_SERVICE);
+		return mm.getCurrentModeType() == Configuration.UI_MODE_TYPE_TELEVISION;
+	}
 }

cmd/tailscale/main.go

@@ -871,8 +871,13 @@ func (a *App) runUI() error {
 			ui.runningExit = p.AdvertisesExitNode()
 			ui.exitLAN.Value = p.ExitNodeAllowLANAccess
 			w.Invalidate()
-		case state.browseURL = <-a.browseURLs:
+		case url := <-a.browseURLs:
 			ui.signinType = noSignin
+			if a.isTV() {
+				ui.ShowQRCode(url)
+			} else {
+				state.browseURL = url
+			}
 			w.Invalidate()
 			a.updateState(activity, state)
 		case newState := <-a.netStates:
@@ -948,6 +953,21 @@ func (a *App) runUI() error {
 	}
 }
 
+func (a *App) isTV() bool {
+	var istv bool
+	err := jni.Do(a.jvm, func(env *jni.Env) error {
+		cls := jni.GetObjectClass(env, a.appCtx)
+		m := jni.GetMethodID(env, cls, "isTV", "()Z")
+		b, err := jni.CallBooleanMethod(env, a.appCtx, m)
+		istv = b
+		return err
+	})
+	if err != nil {
+		fatalErr(err)
+	}
+	return istv
+}
+
 // isReleaseSigned reports whether the app is signed with a release
 // signature.
 func (a *App) isReleaseSigned() bool {

cmd/tailscale/ui.go

@@ -25,6 +25,7 @@ import (
 	"gioui.org/unit"
 	"gioui.org/widget"
 	"gioui.org/widget/material"
+	qrcode "github.com/skip2/go-qrcode"
 	"golang.org/x/exp/shiny/materialdesign/icons"
 	"inet.af/netaddr"
 	"tailscale.com/client/tailscale/apitype"
@@ -76,6 +77,11 @@ type UI struct {
 	showDebugMenu bool
 	runningExit   bool // are we an exit node now?
 
+	qr struct {
+		show bool
+		op   paint.ImageOp
+	}
+
 	intro struct {
 		list  layout.List
 		start widget.Clickable
@@ -255,6 +261,8 @@ func (ui *UI) onBack() bool {
 
 func (ui *UI) activeDialog() *bool {
 	switch {
+	case ui.qr.show:
+		return &ui.qr.show
 	case ui.menu.show:
 		return &ui.menu.show
 	case ui.shareDialog.show:
@@ -414,6 +422,9 @@ func (ui *UI) layout(gtx layout.Context, sysIns system.Insets, state *clientStat
 	const numHeaders = 6
 	n := numHeaders + len(state.Peers)
 	needsLogin := state.backend.State == ipn.NeedsLogin
+	if !needsLogin {
+		ui.qr.show = false
+	}
 	rootGtx := gtx
 	if ui.activeDialog() != nil {
 		rootGtx.Queue = nil
@@ -494,9 +505,20 @@ func (ui *UI) layout(gtx layout.Context, sysIns system.Insets, state *clientStat
 		ui.layoutMenu(gtx, sysIns, expiry, exitID != "" || len(state.backend.Exits) > 0)
 	}
 
+	if ui.qr.show {
+		ui.layoutQR(gtx, sysIns)
+	}
+
 	return events
 }
 
+func (ui *UI) layoutQR(gtx layout.Context, sysIns system.Insets) layout.Dimensions {
+	fill{rgb(0x232323)}.Layout(gtx, gtx.Constraints.Max)
+	return layout.Center.Layout(gtx, func(gtx C) D {
+		return drawImage(gtx, ui.qr.op, unit.Dp(300))
+	})
+}
+
 func (ui *UI) FillShareDialog(targets []*apitype.FileTarget, err error) {
 	ui.shareDialog.error = err
 	ui.shareDialog.loaded = true
@@ -527,6 +549,16 @@ func (ui *UI) ShowMessage(msg string) {
 	ui.message.t0 = time.Now()
 }
 
+func (ui *UI) ShowQRCode(url string) {
+	ui.qr.show = true
+	q, err := qrcode.New(url, qrcode.Medium)
+	if err != nil {
+		fatalErr(err)
+		return
+	}
+	ui.qr.op = paint.NewImageOp(q.Image(512))
+}
+
 // Dismiss is a widget that detects pointer presses.
 type Dismiss struct {
 }

go.mod

@@ -6,6 +6,7 @@ require (
 	eliasnaur.com/font v0.0.0-20200617114307-e02d32decb4b
 	gioui.org v0.0.0-20220228171706-79bfd3adbd32
 	gioui.org/cmd v0.0.0-20210925100615-41f3a7e74ee6
+	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	golang.org/x/exp v0.0.0-20210722180016-6781d3edade3
 	golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9
 	golang.zx2c4.com/wireguard v0.0.0-20211116201604-de7c702ace45

go.sum

@@ -369,6 +369,8 @@ github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeV
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
+github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e h1:MRM5ITcdelLK2j1vwZ3Je0FKVCfqOLp5zO6trqMLYs0=
+github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e/go.mod h1:XV66xRDqSt+GTGFMVlhk3ULuV0y9ZmzeVGR4mloJI3M=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
 github.com/smartystreets/goconvey v1.6.4/go.mod h1:syvi0/a8iFYH4r/RixwvyeAJjdLS9QV7WQ/tjFTllLA=
 github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM=