Add multipath preference, background status API

Add APIs for getMultipathPreference and getRestrictBackgroundStatus.
Both are used by Connectivity to back the external
ConnectivityManager.getRestrictBackgroundStatus, and
ConnectivityManager.getMultipathPreference APIs.

Test: atest CtsNetTestCases
      atest ConnectivityServiceTests
      atest NetworkPolicyManagerServiceTest
Bug: 176289731
Change-Id: I8a03162b2f6691086bb64e75ffd354cdfca7f86a

7 files changed, 63 insertions, 18 deletions

diff --git a/core/api/module-lib-current.txt b/core/api/module-lib-current.txt
index 76e1ade70c66..42892a5f3ad9 100644
--- a/core/api/module-lib-current.txt
+++ b/core/api/module-lib-current.txt
@@ -193,6 +193,8 @@ package android.net {
 
   public class NetworkPolicyManager {
     method @NonNull public static String blockedReasonsToString(int);
+    method @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public int getMultipathPreference(@NonNull android.net.Network);
+    method @RequiresPermission(android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK) public int getRestrictBackgroundStatus(int);
     method public static boolean isUidBlocked(int, boolean);
     method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public void registerNetworkPolicyCallback(@Nullable java.util.concurrent.Executor, @NonNull android.net.NetworkPolicyManager.NetworkPolicyCallback);
     method @RequiresPermission(android.Manifest.permission.OBSERVE_NETWORK_POLICY) public void unregisterNetworkPolicyCallback(@NonNull android.net.NetworkPolicyManager.NetworkPolicyCallback);
diff --git a/core/java/android/net/INetworkPolicyManager.aidl b/core/java/android/net/INetworkPolicyManager.aidl
index 9bf791ba33e0..171c6a2c6a19 100644
--- a/core/java/android/net/INetworkPolicyManager.aidl
+++ b/core/java/android/net/INetworkPolicyManager.aidl
@@ -62,6 +62,7 @@ interface INetworkPolicyManager {
         3 - enabled
     */
     int getRestrictBackgroundByCaller();
+    int getRestrictBackgroundStatus(int uid);
 
     void setDeviceIdleMode(boolean enabled);
     void setWifiMeteredOverride(String networkId, int meteredOverride);
diff --git a/core/java/android/net/NetworkPolicyManager.java b/core/java/android/net/NetworkPolicyManager.java
index 0070796db410..78ad781158a2 100644
--- a/core/java/android/net/NetworkPolicyManager.java
+++ b/core/java/android/net/NetworkPolicyManager.java
@@ -529,6 +529,26 @@ public class NetworkPolicyManager {
     }
 
     /**
+     * Determines if an UID is subject to metered network restrictions while running in background.
+     *
+     * @param uid The UID whose status needs to be checked.
+     * @return {@link ConnectivityManager#RESTRICT_BACKGROUND_STATUS_DISABLED},
+     *         {@link ConnectivityManager##RESTRICT_BACKGROUND_STATUS_ENABLED},
+     *         or {@link ConnectivityManager##RESTRICT_BACKGROUND_STATUS_WHITELISTED} to denote
+     *         the current status of the UID.
+     * @hide
+     */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
+    public int getRestrictBackgroundStatus(int uid) {
+        try {
+            return mService.getRestrictBackgroundStatus(uid);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
      * Override connections to be temporarily marked as either unmetered or congested,
      * along with automatic timeouts if desired.
      *
@@ -663,11 +683,15 @@ public class NetworkPolicyManager {
     }
 
     /**
-     * Get multipath preference for the given network.
+     * Gets a hint on whether it is desirable to use multipath data transfer on the given network.
+     *
+     * @return One of the ConnectivityManager.MULTIPATH_PREFERENCE_* constants.
      *
      * @hide
      */
-    public int getMultipathPreference(Network network) {
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    @RequiresPermission(NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK)
+    public int getMultipathPreference(@NonNull Network network) {
         try {
             return mService.getMultipathPreference(network);
         } catch (RemoteException e) {
diff --git a/packages/Connectivity/framework/src/android/net/ConnectivityManager.java b/packages/Connectivity/framework/src/android/net/ConnectivityManager.java
index ba5eb1090dbf..ace029161cb0 100644
--- a/packages/Connectivity/framework/src/android/net/ConnectivityManager.java
+++ b/packages/Connectivity/framework/src/android/net/ConnectivityManager.java
@@ -62,7 +62,6 @@ import android.os.PersistableBundle;
 import android.os.Process;
 import android.os.RemoteException;
 import android.os.ResultReceiver;
-import android.os.ServiceManager;
 import android.os.ServiceSpecificException;
 import android.os.UserHandle;
 import android.provider.Settings;
@@ -842,7 +841,6 @@ public class ConnectivityManager {
 
     private final Context mContext;
 
-    private INetworkPolicyManager mNPManager;
     private final TetheringManager mTetheringManager;
 
     /**
@@ -4764,17 +4762,6 @@ public class ConnectivityManager {
     public @interface RestrictBackgroundStatus {
     }
 
-    private INetworkPolicyManager getNetworkPolicyManager() {
-        synchronized (this) {
-            if (mNPManager != null) {
-                return mNPManager;
-            }
-            mNPManager = INetworkPolicyManager.Stub.asInterface(ServiceManager
-                    .getService(Context.NETWORK_POLICY_SERVICE));
-            return mNPManager;
-        }
-    }
-
     /**
      * Determines if the calling application is subject to metered network restrictions while
      * running on background.
@@ -4785,7 +4772,7 @@ public class ConnectivityManager {
      */
     public @RestrictBackgroundStatus int getRestrictBackgroundStatus() {
         try {
-            return getNetworkPolicyManager().getRestrictBackgroundByCaller();
+            return mService.getRestrictBackgroundStatusByCaller();
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         }
diff --git a/packages/Connectivity/framework/src/android/net/IConnectivityManager.aidl b/packages/Connectivity/framework/src/android/net/IConnectivityManager.aidl
index d83cc163b53f..98f3d40c0b07 100644
--- a/packages/Connectivity/framework/src/android/net/IConnectivityManager.aidl
+++ b/packages/Connectivity/framework/src/android/net/IConnectivityManager.aidl
@@ -220,4 +220,6 @@ interface IConnectivityManager
 
     void setProfileNetworkPreference(in UserHandle profile, int preference,
             in IOnCompleteListener listener);
+
+    int getRestrictBackgroundStatusByCaller();
 }
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 6f0007b429ac..86083917096d 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -106,6 +106,7 @@ import android.net.ConnectivityDiagnosticsManager.ConnectivityReport;
 import android.net.ConnectivityDiagnosticsManager.DataStallReport;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.NetworkCallback;
+import android.net.ConnectivityManager.RestrictBackgroundStatus;
 import android.net.ConnectivitySettingsManager;
 import android.net.DataStallReportParcelable;
 import android.net.DnsResolverServiceManager;
@@ -1997,6 +1998,18 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
     }
 
+    @Override
+    public @RestrictBackgroundStatus int getRestrictBackgroundStatusByCaller() {
+        enforceAccessPermission();
+        final int callerUid = Binder.getCallingUid();
+        final long token = Binder.clearCallingIdentity();
+        try {
+            return mPolicyManager.getRestrictBackgroundStatus(callerUid);
+        } finally {
+            Binder.restoreCallingIdentity(token);
+        }
+    }
+
     // TODO: Consider delete this function or turn it into a no-op method.
     @Override
     public NetworkState[] getAllNetworkState() {
@@ -4402,7 +4415,13 @@ public class ConnectivityService extends IConnectivityManager.Stub
         final NetworkPolicyManager netPolicyManager =
                  mContext.getSystemService(NetworkPolicyManager.class);
 
-        final int networkPreference = netPolicyManager.getMultipathPreference(network);
+        final long token = Binder.clearCallingIdentity();
+        final int networkPreference;
+        try {
+            networkPreference = netPolicyManager.getMultipathPreference(network);
+        } finally {
+            Binder.restoreCallingIdentity(token);
+        }
         if (networkPreference != 0) {
             return networkPreference;
         }
diff --git a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
index 735381873c05..0fa6283cb59a 100644
--- a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
+++ b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
@@ -263,6 +263,7 @@ import com.android.internal.util.IndentingPrintWriter;
 import com.android.internal.util.StatLogger;
 import com.android.internal.util.XmlUtils;
 import com.android.net.module.util.NetworkIdentityUtils;
+import com.android.net.module.util.PermissionUtils;
 import com.android.server.EventLogTags;
 import com.android.server.LocalServices;
 import com.android.server.ServiceThread;
@@ -3109,8 +3110,16 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
     @Override
     public int getRestrictBackgroundByCaller() {
         mContext.enforceCallingOrSelfPermission(ACCESS_NETWORK_STATE, TAG);
-        final int uid = Binder.getCallingUid();
+        return getRestrictBackgroundStatusInternal(Binder.getCallingUid());
+    }
+
+    @Override
+    public int getRestrictBackgroundStatus(int uid) {
+        PermissionUtils.enforceNetworkStackPermission(mContext);
+        return getRestrictBackgroundStatusInternal(uid);
+    }
 
+    private int getRestrictBackgroundStatusInternal(int uid) {
         synchronized (mUidRulesFirstLock) {
             // Must clear identity because getUidPolicy() is restricted to system.
             final long token = Binder.clearCallingIdentity();
@@ -3579,6 +3588,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub {
      * Get multipath preference value for the given network.
      */
     public int getMultipathPreference(Network network) {
+        PermissionUtils.enforceNetworkStackPermission(mContext);
         final Integer preference = mMultipathPolicyTracker.getMultipathPreference(network);
         if (preference != null) {
             return preference;