Merge "Add an API hint for metered multipath traffic."

core/java/android/net/ConnectivityManager.java

@@ -3406,6 +3406,75 @@ public class ConnectivityManager {
         }
     }
 
+    /**
+     * It is acceptable to briefly use multipath data to provide seamless connectivity for
+     * time-sensitive user-facing operations when the system default network is temporarily
+     * unresponsive. The amount of data should be limited (less than one megabyte), and the
+     * operation should be infrequent to ensure that data usage is limited.
+     *
+     * An example of such an operation might be a time-sensitive foreground activity, such as a
+     * voice command, that the user is performing while walking out of range of a Wi-Fi network.
+     */
+    public static final int MULTIPATH_PREFERENCE_HANDOVER = 1 << 0;
+
+    /**
+     * It is acceptable to use small amounts of multipath data on an ongoing basis to provide
+     * a backup channel for traffic that is primarily going over another network.
+     *
+     * An example might be maintaining backup connections to peers or servers for the purpose of
+     * fast fallback if the default network is temporarily unresponsive or disconnects. The traffic
+     * on backup paths should be negligible compared to the traffic on the main path.
+     */
+    public static final int MULTIPATH_PREFERENCE_RELIABILITY = 1 << 1;
+
+    /**
+     * It is acceptable to use metered data to improve network latency and performance.
+     */
+    public static final int MULTIPATH_PREFERENCE_PERFORMANCE = 1 << 2;
+
+    /**
+     * Return value to use for unmetered networks. On such networks we currently set all the flags
+     * to true.
+     * @hide
+     */
+    public static final int MULTIPATH_PREFERENCE_UNMETERED =
+            MULTIPATH_PREFERENCE_HANDOVER |
+            MULTIPATH_PREFERENCE_RELIABILITY |
+            MULTIPATH_PREFERENCE_PERFORMANCE;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(flag = true, value = {
+            MULTIPATH_PREFERENCE_HANDOVER,
+            MULTIPATH_PREFERENCE_RELIABILITY,
+            MULTIPATH_PREFERENCE_PERFORMANCE,
+    })
+    public @interface MultipathPreference {
+    }
+
+    /**
+     * Provides a hint to the calling application on whether it is desirable to use the
+     * multinetwork APIs (e.g., {@link Network#openConnection}, {@link Network#bindSocket}, etc.)
+     * for multipath data transfer on this network when it is not the system default network.
+     * Applications desiring to use multipath network protocols should call this method before
+     * each such operation.
+     * <p>
+     * This method requires the caller to hold the permission
+     * {@link android.Manifest.permission#ACCESS_NETWORK_STATE}.
+     *
+     * @param network The network on which the application desires to use multipath data.
+     *                If {@code null}, this method will return the a preference that will generally
+     *                apply to metered networks.
+     * @return a bitwise OR of zero or more of the  {@code MULTIPATH_PREFERENCE_*} constants.
+     */
+    public @MultipathPreference int getMultipathPreference(Network network) {
+        try {
+            return mService.getMultipathPreference(network);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
     /**
      * Resets all connectivity manager settings back to factory defaults.
      * @hide

core/java/android/net/IConnectivityManager.aidl

@@ -161,6 +161,8 @@ interface IConnectivityManager
     void setAcceptUnvalidated(in Network network, boolean accept, boolean always);
     void setAvoidUnvalidated(in Network network);
 
+    int getMultipathPreference(in Network Network);
+
     int getRestoreDefaultNetworkDelay(int networkType);
 
     boolean addVpnAddress(String address, int prefixLength);

services/core/java/com/android/server/ConnectivityService.java

@@ -2838,6 +2838,18 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
     }
 
+    @Override
+    public int getMultipathPreference(Network network) {
+        enforceAccessPermission();
+
+        NetworkAgentInfo nai = getNetworkAgentInfoForNetwork(network);
+        if (nai != null && !nai.networkInfo.isMetered()) {
+            return ConnectivityManager.MULTIPATH_PREFERENCE_UNMETERED;
+        }
+
+        return mMultinetworkPolicyTracker.getMeteredMultipathPreference();
+    }
+
     private class InternalHandler extends Handler {
         public InternalHandler(Looper looper) {
             super(looper);

services/net/java/android/net/util/MultinetworkPolicyTracker.java

@@ -22,6 +22,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.database.ContentObserver;
+import android.net.ConnectivityManager;
 import android.net.Uri;
 import android.os.Handler;
 import android.os.Message;
@@ -29,10 +30,14 @@ import android.os.UserHandle;
 import android.provider.Settings;
 import android.util.Slog;
 
+import java.util.Arrays;
+import java.util.List;
+
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.R;
 
 import static android.provider.Settings.Global.NETWORK_AVOID_BAD_WIFI;
+import static android.provider.Settings.Global.NETWORK_METERED_MULTIPATH_PREFERENCE;
 
 /**
  * A class to encapsulate management of the "Smart Networking" capability of
@@ -57,12 +62,13 @@ public class MultinetworkPolicyTracker {
     private final Context mContext;
     private final Handler mHandler;
     private final Runnable mReevaluateRunnable;
-    private final Uri mAvoidBadWifiUri;
+    private final List<Uri> mSettingsUris;
     private final ContentResolver mResolver;
     private final SettingObserver mSettingObserver;
     private final BroadcastReceiver mBroadcastReceiver;
 
     private volatile boolean mAvoidBadWifi = true;
+    private volatile int mMeteredMultipathPreference;
 
     public MultinetworkPolicyTracker(Context ctx, Handler handler) {
         this(ctx, handler, null);
@@ -72,9 +78,14 @@ public class MultinetworkPolicyTracker {
         mContext = ctx;
         mHandler = handler;
         mReevaluateRunnable = () -> {
-            if (updateAvoidBadWifi() && avoidBadWifiCallback != null) avoidBadWifiCallback.run();
+            if (updateAvoidBadWifi() && avoidBadWifiCallback != null) {
+                avoidBadWifiCallback.run();
+            }
+            updateMeteredMultipathPreference();
         };
-        mAvoidBadWifiUri = Settings.Global.getUriFor(NETWORK_AVOID_BAD_WIFI);
+        mSettingsUris = Arrays.asList(
+            Settings.Global.getUriFor(NETWORK_AVOID_BAD_WIFI),
+            Settings.Global.getUriFor(NETWORK_METERED_MULTIPATH_PREFERENCE));
         mResolver = mContext.getContentResolver();
         mSettingObserver = new SettingObserver();
         mBroadcastReceiver = new BroadcastReceiver() {
@@ -85,10 +96,13 @@ public class MultinetworkPolicyTracker {
         };
 
         updateAvoidBadWifi();
+        updateMeteredMultipathPreference();
     }
 
     public void start() {
-        mResolver.registerContentObserver(mAvoidBadWifiUri, false, mSettingObserver);
+        for (Uri uri : mSettingsUris) {
+            mResolver.registerContentObserver(uri, false, mSettingObserver);
+        }
 
         final IntentFilter intentFilter = new IntentFilter();
         intentFilter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);
@@ -108,6 +122,10 @@ public class MultinetworkPolicyTracker {
         return mAvoidBadWifi;
     }
 
+    public int getMeteredMultipathPreference() {
+        return mMeteredMultipathPreference;
+    }
+
     /**
      * Whether the device or carrier configuration disables avoiding bad wifi by default.
      */
@@ -138,6 +156,23 @@ public class MultinetworkPolicyTracker {
         return mAvoidBadWifi != prev;
     }
 
+    /**
+     * The default (device and carrier-dependent) value for metered multipath preference.
+     */
+    public int configMeteredMultipathPreference() {
+        return mContext.getResources().getInteger(
+                R.integer.config_networkMeteredMultipathPreference);
+    }
+
+    public void updateMeteredMultipathPreference() {
+        String setting = Settings.Global.getString(mResolver, NETWORK_METERED_MULTIPATH_PREFERENCE);
+        try {
+            mMeteredMultipathPreference = Integer.parseInt(setting);
+        } catch (NumberFormatException e) {
+            mMeteredMultipathPreference = configMeteredMultipathPreference();
+        }
+    }
+
     private class SettingObserver extends ContentObserver {
         public SettingObserver() {
             super(null);
@@ -150,7 +185,9 @@ public class MultinetworkPolicyTracker {
 
         @Override
         public void onChange(boolean selfChange, Uri uri) {
-            if (!mAvoidBadWifiUri.equals(uri)) return;
+            if (!mSettingsUris.contains(uri)) {
+                Slog.wtf(TAG, "Unexpected settings observation: " + uri);
+            }
             reevaluate();
         }
     }

tests/net/java/com/android/server/ConnectivityServiceTest.java

@@ -632,6 +632,7 @@ public class ConnectivityServiceTest extends AndroidTestCase {
 
     private class WrappedMultinetworkPolicyTracker extends MultinetworkPolicyTracker {
         public volatile boolean configRestrictsAvoidBadWifi;
+        public volatile int configMeteredMultipathPreference;
 
         public WrappedMultinetworkPolicyTracker(Context c, Handler h, Runnable r) {
             super(c, h, r);
@@ -641,6 +642,11 @@ public class ConnectivityServiceTest extends AndroidTestCase {
         public boolean configRestrictsAvoidBadWifi() {
             return configRestrictsAvoidBadWifi;
         }
+
+        @Override
+        public int configMeteredMultipathPreference() {
+            return configMeteredMultipathPreference;
+        }
     }
 
     private class WrappedConnectivityService extends ConnectivityService {
@@ -2454,6 +2460,26 @@ public class ConnectivityServiceTest extends AndroidTestCase {
         mCm.unregisterNetworkCallback(defaultCallback);
     }
 
+    @SmallTest
+    public void testMeteredMultipathPreferenceSetting() throws Exception {
+        final ContentResolver cr = mServiceContext.getContentResolver();
+        final WrappedMultinetworkPolicyTracker tracker = mService.getMultinetworkPolicyTracker();
+        final String settingName = Settings.Global.NETWORK_METERED_MULTIPATH_PREFERENCE;
+
+        for (int config : Arrays.asList(0, 3, 2)) {
+            for (String setting: Arrays.asList(null, "0", "2", "1")) {
+                tracker.configMeteredMultipathPreference = config;
+                Settings.Global.putString(cr, settingName, setting);
+                tracker.reevaluate();
+                mService.waitForIdle();
+
+                final int expected = (setting != null) ? Integer.parseInt(setting) : config;
+                String msg = String.format("config=%d, setting=%s", config, setting);
+                assertEquals(msg, expected, mCm.getMultipathPreference(null));
+            }
+        }
+    }
+
     /**
      * Validate that a satisfied network request does not trigger onUnavailable() once the
      * time-out period expires.