Merge pull request #26 from tailscale/linkproperties

ui: more robust isConnected check.

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

@@ -26,6 +26,7 @@ import android.provider.Settings;
 import android.net.ConnectivityManager;
 import android.net.LinkProperties;
 import android.net.Network;
+import android.net.NetworkInfo;
 import android.net.NetworkRequest;
 import android.net.Uri;
 import android.net.VpnService;
@@ -98,14 +99,23 @@ public class App extends Application {
 	private void registerNetworkCallback() {
 		ConnectivityManager cMgr = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
 		cMgr.registerNetworkCallback(new NetworkRequest.Builder().build(), new ConnectivityManager.NetworkCallback() {
+			private void reportConnectivityChange() {
+				NetworkInfo active = cMgr.getActiveNetworkInfo();
+				// https://developer.android.com/training/monitoring-device-state/connectivity-status-type
+				boolean isConnected = active != null && active.isConnectedOrConnecting();
+				onConnectivityChanged(isConnected);
+			}
+
 			@Override
 			public void onLost(Network network) {
-				onConnectivityChanged(false);
+				super.onLost(network);
+				this.reportConnectivityChange();
 			}
 
 			@Override
 			public void onLinkPropertiesChanged(Network network, LinkProperties linkProperties) {
-				onConnectivityChanged(true);
+				super.onLinkPropertiesChanged(network, linkProperties);
+				this.reportConnectivityChange();
 			}
 		});
 	}

cmd/tailscale/main.go

@@ -471,6 +471,9 @@ func (a *App) runBackend() error {
 				}
 			}
 		case connected := <-onConnectivityChange:
+			if state.LostInternet != !connected {
+				log.Printf("LostInternet state change: %v -> %v", state.LostInternet, !connected)
+			}
 			state.LostInternet = !connected
 			if b != nil {
 				go b.LinkChange()