diff --git a/service/src/com/android/server/connectivity/PermissionMonitor.java b/service/src/com/android/server/connectivity/PermissionMonitor.java
index 0c883be..f596c4a 100755
--- a/service/src/com/android/server/connectivity/PermissionMonitor.java
+++ b/service/src/com/android/server/connectivity/PermissionMonitor.java
@@ -74,7 +74,6 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.Set;
 
 /**
@@ -86,8 +85,6 @@
 public class PermissionMonitor {
     private static final String TAG = "PermissionMonitor";
     private static final boolean DBG = true;
-    protected static final Boolean SYSTEM = Boolean.TRUE;
-    protected static final Boolean NETWORK = Boolean.FALSE;
     private static final int VERSION_Q = Build.VERSION_CODES.Q;
 
     private final PackageManager mPackageManager;
@@ -102,7 +99,7 @@
 
     // Keys are appIds. Values are true for SYSTEM permission and false for NETWORK permission.
     @GuardedBy("this")
-    private final Map<Integer, Boolean> mApps = new HashMap<>();
+    private final SparseIntArray mApps = new SparseIntArray();
 
     // Keys are active non-bypassable and fully-routed VPN's interface name, Values are uid ranges
     // for apps under the VPN
@@ -194,6 +191,23 @@
         mContext = context;
     }
 
+    private int getPackageNetdNetworkPermission(@NonNull final PackageInfo app) {
+        if (hasRestrictedNetworkPermission(app)) {
+            return PERMISSION_SYSTEM;
+        }
+        if (hasNetworkPermission(app)) {
+            return PERMISSION_NETWORK;
+        }
+        return PERMISSION_NONE;
+    }
+
+    static boolean isHigherNetworkPermission(final int targetPermission,
+            final int currentPermission) {
+        // This is relied on strict order of network permissions (SYSTEM > NETWORK > NONE), and it
+        // is enforced in tests.
+        return targetPermission > currentPermission;
+    }
+
     // Intended to be called only once at startup, after the system is ready. Installs a broadcast
     // receiver to monitor ongoing UID changes, so this shouldn't/needn't be called again.
     public synchronized void startMonitoring() {
@@ -247,16 +261,9 @@
             final int appId = UserHandle.getAppId(uid);
             mAllApps.add(appId);
 
-            boolean hasNetworkPermission = hasNetworkPermission(app);
-            boolean hasRestrictedPermission = hasRestrictedNetworkPermission(app);
-
-            if (hasNetworkPermission || hasRestrictedPermission) {
-                final Boolean permission = mApps.get(appId);
-                // If multiple packages share a UID (cf: android:sharedUserId) and ask for different
-                // permissions, don't downgrade (i.e., if it's already SYSTEM, leave it as is).
-                if (permission == null || permission == NETWORK) {
-                    mApps.put(appId, hasRestrictedPermission);
-                }
+            final int permission = getPackageNetdNetworkPermission(app);
+            if (isHigherNetworkPermission(permission, mApps.get(appId, PERMISSION_NONE))) {
+                mApps.put(appId, permission);
             }
 
             //TODO: unify the management of the permissions into one codepath.
@@ -353,25 +360,29 @@
         // networks. mApps contains the result of checks for both hasNetworkPermission and
         // hasRestrictedNetworkPermission. If uid is in the mApps list that means uid has one of
         // permissions at least.
-        return mApps.containsKey(UserHandle.getAppId(uid));
+        return mApps.get(UserHandle.getAppId(uid), PERMISSION_NONE) != PERMISSION_NONE;
     }
 
     /**
      * Returns whether the given uid has permission to use restricted networks.
      */
     public synchronized boolean hasRestrictedNetworksPermission(int uid) {
-        return Boolean.TRUE.equals(mApps.get(UserHandle.getAppId(uid)));
+        return PERMISSION_SYSTEM == mApps.get(UserHandle.getAppId(uid), PERMISSION_NONE);
     }
 
-    private void update(Set<UserHandle> users, Map<Integer, Boolean> apps, boolean add) {
+    private void update(Set<UserHandle> users, SparseIntArray apps, boolean add) {
         List<Integer> network = new ArrayList<>();
         List<Integer> system = new ArrayList<>();
-        for (Entry<Integer, Boolean> app : apps.entrySet()) {
-            List<Integer> list = app.getValue() ? system : network;
+        for (int i = 0; i < apps.size(); i++) {
+            final int permission = apps.valueAt(i);
+            if (PERMISSION_NONE == permission) {
+                continue; // Normally NONE is not stored in this map, but just in case
+            }
+            List<Integer> list = (PERMISSION_SYSTEM == permission) ? system : network;
             for (UserHandle user : users) {
                 if (user == null) continue;
 
-                list.add(user.getUid(app.getKey()));
+                list.add(user.getUid(apps.keyAt(i)));
             }
         }
         try {
@@ -396,10 +407,7 @@
      */
     public synchronized void onUserAdded(@NonNull UserHandle user) {
         mUsers.add(user);
-
-        Set<UserHandle> users = new HashSet<>();
-        users.add(user);
-        update(users, mApps, true);
+        update(Set.of(user), mApps, true);
     }
 
     /**
@@ -411,10 +419,7 @@
      */
     public synchronized void onUserRemoved(@NonNull UserHandle user) {
         mUsers.remove(user);
-
-        Set<UserHandle> users = new HashSet<>();
-        users.add(user);
-        update(users, mApps, false);
+        update(Set.of(user), mApps, false);
     }
 
     /**
@@ -426,17 +431,16 @@
      *             permission.
      */
     @VisibleForTesting
-    protected Boolean highestPermissionForUid(Boolean currentPermission, String name) {
-        if (currentPermission == SYSTEM) {
+    protected int highestPermissionForUid(int currentPermission, String name) {
+        if (currentPermission == PERMISSION_SYSTEM) {
             return currentPermission;
         }
         try {
             final PackageInfo app = mPackageManager.getPackageInfo(name,
                     GET_PERMISSIONS | MATCH_ANY_USER);
-            final boolean isNetwork = hasNetworkPermission(app);
-            final boolean hasRestrictedPermission = hasRestrictedNetworkPermission(app);
-            if (isNetwork || hasRestrictedPermission) {
-                currentPermission = hasRestrictedPermission;
+            final int permission = getPackageNetdNetworkPermission(app);
+            if (isHigherNetworkPermission(permission, currentPermission)) {
+                return permission;
             }
         } catch (NameNotFoundException e) {
             // App not found.
@@ -465,6 +469,17 @@
         return permission;
     }
 
+    private synchronized void updateVpnUid(int uid, boolean add) {
+        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
+            if (UidRange.containsUid(vpn.getValue(), uid)) {
+                final Set<Integer> changedUids = new HashSet<>();
+                changedUids.add(uid);
+                removeBypassingUids(changedUids, -1 /* vpnAppUid */);
+                updateVpnUidsInterfaceRules(vpn.getKey(), changedUids, add);
+            }
+        }
+    }
+
     /**
      * Called when a package is added.
      *
@@ -479,38 +494,32 @@
 
         // If multiple packages share a UID (cf: android:sharedUserId) and ask for different
         // permissions, don't downgrade (i.e., if it's already SYSTEM, leave it as is).
-        final Boolean permission = highestPermissionForUid(mApps.get(appId), packageName);
-        if (permission != mApps.get(appId)) {
+        final int currentPermission = mApps.get(appId, PERMISSION_NONE);
+        final int permission = highestPermissionForUid(currentPermission, packageName);
+        if (permission != currentPermission) {
             mApps.put(appId, permission);
 
-            Map<Integer, Boolean> apps = new HashMap<>();
+            SparseIntArray apps = new SparseIntArray();
             apps.put(appId, permission);
             update(mUsers, apps, true);
         }
 
         // If the newly-installed package falls within some VPN's uid range, update Netd with it.
-        // This needs to happen after the mApps update above, since removeBypassingUids() depends
-        // on mApps to check if the package can bypass VPN.
-        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
-            if (UidRange.containsUid(vpn.getValue(), uid)) {
-                final Set<Integer> changedUids = new HashSet<>();
-                changedUids.add(uid);
-                removeBypassingUids(changedUids, /* vpnAppUid */ -1);
-                updateVpnUids(vpn.getKey(), changedUids, true);
-            }
-        }
+        // This needs to happen after the mApps update above, since removeBypassingUids() in
+        // updateVpnUid() depends on mApps to check if the package can bypass VPN.
+        updateVpnUid(uid, true /* add */);
         mAllApps.add(appId);
     }
 
-    private Boolean highestUidNetworkPermission(int uid) {
-        Boolean permission = null;
+    private int highestUidNetworkPermission(int uid) {
+        int permission = PERMISSION_NONE;
         final String[] packages = mPackageManager.getPackagesForUid(uid);
         if (!CollectionUtils.isEmpty(packages)) {
             for (String name : packages) {
                 // If multiple packages have the same UID, give the UID all permissions that
                 // any package in that UID has.
                 permission = highestPermissionForUid(permission, name);
-                if (permission == SYSTEM) {
+                if (permission == PERMISSION_SYSTEM) {
                     break;
                 }
             }
@@ -531,40 +540,32 @@
         sendPackagePermissionsForAppId(appId, getPermissionForUid(uid));
 
         // If the newly-removed package falls within some VPN's uid range, update Netd with it.
-        // This needs to happen before the mApps update below, since removeBypassingUids() depends
-        // on mApps to check if the package can bypass VPN.
-        for (Map.Entry<String, Set<UidRange>> vpn : mVpnUidRanges.entrySet()) {
-            if (UidRange.containsUid(vpn.getValue(), uid)) {
-                final Set<Integer> changedUids = new HashSet<>();
-                changedUids.add(uid);
-                removeBypassingUids(changedUids, /* vpnAppUid */ -1);
-                updateVpnUids(vpn.getKey(), changedUids, false);
-            }
-        }
+        // This needs to happen before the mApps update below, since removeBypassingUids() in
+        // updateVpnUid() depends on mApps to check if the package can bypass VPN.
+        updateVpnUid(uid, false /* add */);
         // If the package has been removed from all users on the device, clear it form mAllApps.
         if (mPackageManager.getNameForUid(uid) == null) {
             mAllApps.remove(appId);
         }
 
-        Map<Integer, Boolean> apps = new HashMap<>();
-        final Boolean permission = highestUidNetworkPermission(uid);
-        if (permission == SYSTEM) {
+        final int permission = highestUidNetworkPermission(uid);
+        if (permission == PERMISSION_SYSTEM) {
             // An app with this UID still has the SYSTEM permission.
             // Therefore, this UID must already have the SYSTEM permission.
             // Nothing to do.
             return;
         }
+        // If the permissions of this UID have not changed, do nothing.
+        if (permission == mApps.get(appId, PERMISSION_NONE)) return;
 
-        if (permission == mApps.get(appId)) {
-            // The permissions of this UID have not changed. Nothing to do.
-            return;
-        } else if (permission != null) {
+        final SparseIntArray apps = new SparseIntArray();
+        if (permission != PERMISSION_NONE) {
             mApps.put(appId, permission);
             apps.put(appId, permission);
             update(mUsers, apps, true);
         } else {
-            mApps.remove(appId);
-            apps.put(appId, NETWORK);  // doesn't matter which permission we pick here
+            mApps.delete(appId);
+            apps.put(appId, PERMISSION_NETWORK);  // doesn't matter which permission we pick here
             update(mUsers, apps, false);
         }
     }
@@ -611,7 +612,7 @@
         // but that's safe.
         final Set<Integer> changedUids = intersectUids(rangesToAdd, mAllApps);
         removeBypassingUids(changedUids, vpnAppUid);
-        updateVpnUids(iface, changedUids, true);
+        updateVpnUidsInterfaceRules(iface, changedUids, true /* add */);
         if (mVpnUidRanges.containsKey(iface)) {
             mVpnUidRanges.get(iface).addAll(rangesToAdd);
         } else {
@@ -632,7 +633,7 @@
         // ranges and update Netd about them.
         final Set<Integer> changedUids = intersectUids(rangesToRemove, mAllApps);
         removeBypassingUids(changedUids, vpnAppUid);
-        updateVpnUids(iface, changedUids, false);
+        updateVpnUidsInterfaceRules(iface, changedUids, false /* add */);
         Set<UidRange> existingRanges = mVpnUidRanges.getOrDefault(iface, null);
         if (existingRanges == null) {
             loge("Attempt to remove unknown vpn uid Range iface = " + iface);
@@ -671,7 +672,7 @@
     /**
      * Remove all apps which can elect to bypass the VPN from the list of uids
      *
-     * An app can elect to bypass the VPN if it hold SYSTEM permission, or if its the active VPN
+     * An app can elect to bypass the VPN if it holds SYSTEM permission, or if it's the active VPN
      * app itself.
      *
      * @param uids The list of uids to operate on
@@ -679,7 +680,8 @@
      */
     private void removeBypassingUids(Set<Integer> uids, int vpnAppUid) {
         uids.remove(vpnAppUid);
-        uids.removeIf(uid -> mApps.getOrDefault(UserHandle.getAppId(uid), NETWORK) == SYSTEM);
+        uids.removeIf(uid ->
+                mApps.get(UserHandle.getAppId(uid), PERMISSION_NONE) == PERMISSION_SYSTEM);
     }
 
     /**
@@ -693,7 +695,7 @@
      * @param add {@code true} if the uids are to be added to the interface, {@code false} if they
      *        are to be removed from the interface.
      */
-    private void updateVpnUids(String iface, Set<Integer> uids, boolean add) {
+    private void updateVpnUidsInterfaceRules(String iface, Set<Integer> uids, boolean add) {
         if (uids.size() == 0) {
             return;
         }
@@ -811,17 +813,18 @@
         updateUidsAllowedOnRestrictedNetworks(mDeps.getUidsAllowedOnRestrictedNetworks(mContext));
         uidsToUpdate.addAll(mUidsAllowedOnRestrictedNetworks);
 
-        final Map<Integer, Boolean> updatedUids = new HashMap<>();
-        final Map<Integer, Boolean> removedUids = new HashMap<>();
+        final SparseIntArray updatedUids = new SparseIntArray();
+        final SparseIntArray removedUids = new SparseIntArray();
 
         // Step2. For each uid to update, find out its new permission.
         for (Integer uid : uidsToUpdate) {
-            final Boolean permission = highestUidNetworkPermission(uid);
+            final int permission = highestUidNetworkPermission(uid);
 
             final int appId = UserHandle.getAppId(uid);
-            if (null == permission) {
-                removedUids.put(appId, NETWORK); // Doesn't matter which permission is set here.
-                mApps.remove(appId);
+            if (PERMISSION_NONE == permission) {
+                // Doesn't matter which permission is set here.
+                removedUids.put(appId, PERMISSION_NETWORK);
+                mApps.delete(appId);
             } else {
                 updatedUids.put(appId, permission);
                 mApps.put(appId, permission);
diff --git a/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java b/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
index b7b3e29..ecda338 100644
--- a/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/PermissionMonitorTest.java
@@ -32,6 +32,7 @@
 import static android.content.pm.PackageManager.MATCH_ANY_USER;
 import static android.net.ConnectivitySettingsManager.UIDS_ALLOWED_ON_RESTRICTED_NETWORKS;
 import static android.net.INetd.PERMISSION_INTERNET;
+import static android.net.INetd.PERMISSION_NETWORK;
 import static android.net.INetd.PERMISSION_NONE;
 import static android.net.INetd.PERMISSION_SYSTEM;
 import static android.net.INetd.PERMISSION_UNINSTALLED;
@@ -39,8 +40,7 @@
 import static android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK;
 import static android.os.Process.SYSTEM_UID;
 
-import static com.android.server.connectivity.PermissionMonitor.NETWORK;
-import static com.android.server.connectivity.PermissionMonitor.SYSTEM;
+import static com.android.server.connectivity.PermissionMonitor.isHigherNetworkPermission;
 
 import static junit.framework.Assert.fail;
 
@@ -102,7 +102,6 @@
 
 import java.lang.reflect.Array;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Set;
 
@@ -152,7 +151,7 @@
         MockitoAnnotations.initMocks(this);
         when(mContext.getPackageManager()).thenReturn(mPackageManager);
         when(mContext.getSystemService(eq(Context.USER_SERVICE))).thenReturn(mUserManager);
-        when(mUserManager.getUserHandles(eq(true))).thenReturn(List.of(MOCK_USER1, MOCK_USER2));
+        doReturn(List.of(MOCK_USER1)).when(mUserManager).getUserHandles(eq(true));
         when(mContext.getSystemServiceName(SystemConfigManager.class))
                 .thenReturn(Context.SYSTEM_CONFIG_SERVICE);
         when(mContext.getSystemService(Context.SYSTEM_CONFIG_SERVICE))
@@ -173,8 +172,7 @@
         mPermissionMonitor = new PermissionMonitor(mContext, mNetdService, mDeps);
         mNetdMonitor = new NetdMonitor(mNetdService);
 
-        when(mPackageManager.getInstalledPackages(anyInt())).thenReturn(/* empty app list */ null);
-        mPermissionMonitor.startMonitoring();
+        doReturn(List.of()).when(mPackageManager).getInstalledPackages(anyInt());
     }
 
     private boolean hasRestrictedNetworkPermission(String partition, int targetSdkVersion,
@@ -506,21 +504,22 @@
     }
 
     private class NetdMonitor {
-        private final HashMap<Integer, Boolean> mUidsNetworkPermission = new HashMap<>();
-        private final HashMap<Integer, Integer> mAppIdsTrafficPermission = new HashMap<>();
+        private final SparseIntArray mUidsNetworkPermission = new SparseIntArray();
+        private final SparseIntArray mAppIdsTrafficPermission = new SparseIntArray();
+        private static final int DOES_NOT_EXIST = -2;
 
         NetdMonitor(INetd mockNetd) throws Exception {
             // Add hook to verify and track result of networkSetPermission.
             doAnswer((InvocationOnMock invocation) -> {
                 final Object[] args = invocation.getArguments();
-                final Boolean isSystem = args[0].equals(PERMISSION_SYSTEM);
+                final int permission = (int) args[0];
                 for (final int uid : (int[]) args[1]) {
                     // TODO: Currently, permission monitor will send duplicate commands for each uid
                     // corresponding to each user. Need to fix that and uncomment below test.
                     // if (mApps.containsKey(uid) && mApps.get(uid) == isSystem) {
                     //     fail("uid " + uid + " is already set to " + isSystem);
                     // }
-                    mUidsNetworkPermission.put(uid, isSystem);
+                    mUidsNetworkPermission.put(uid, permission);
                 }
                 return null;
             }).when(mockNetd).networkSetPermissionForUser(anyInt(), any(int[].class));
@@ -534,7 +533,7 @@
                     // if (!mApps.containsKey(uid)) {
                     //     fail("uid " + uid + " does not exist.");
                     // }
-                    mUidsNetworkPermission.remove(uid);
+                    mUidsNetworkPermission.delete(uid);
                 }
                 return null;
             }).when(mockNetd).networkClearPermissionForUser(any(int[].class));
@@ -550,11 +549,11 @@
             }).when(mockNetd).trafficSetNetPermForUids(anyInt(), any(int[].class));
         }
 
-        public void expectNetworkPerm(Boolean permission, UserHandle[] users, int... appIds) {
+        public void expectNetworkPerm(int permission, UserHandle[] users, int... appIds) {
             for (final UserHandle user : users) {
                 for (final int appId : appIds) {
                     final int uid = user.getUid(appId);
-                    if (!mUidsNetworkPermission.containsKey(uid)) {
+                    if (mUidsNetworkPermission.get(uid, DOES_NOT_EXIST) == DOES_NOT_EXIST) {
                         fail("uid " + uid + " does not exist.");
                     }
                     if (mUidsNetworkPermission.get(uid) != permission) {
@@ -568,7 +567,7 @@
             for (final UserHandle user : users) {
                 for (final int appId : appIds) {
                     final int uid = user.getUid(appId);
-                    if (mUidsNetworkPermission.containsKey(uid)) {
+                    if (mUidsNetworkPermission.get(uid, DOES_NOT_EXIST) != DOES_NOT_EXIST) {
                         fail("uid " + uid + " has listed permissions, expected none.");
                     }
                 }
@@ -577,7 +576,7 @@
 
         public void expectTrafficPerm(int permission, int... appIds) {
             for (final int appId : appIds) {
-                if (!mAppIdsTrafficPermission.containsKey(appId)) {
+                if (mAppIdsTrafficPermission.get(appId, DOES_NOT_EXIST) == DOES_NOT_EXIST) {
                     fail("appId " + appId + " does not exist.");
                 }
                 if (mAppIdsTrafficPermission.get(appId) != permission) {
@@ -599,17 +598,21 @@
         buildAndMockPackageInfoWithPermissions(SYSTEM_PACKAGE2, SYSTEM_APP_UID1,
                 CHANGE_NETWORK_STATE);
 
-        // Add SYSTEM_PACKAGE2, expect only have network permission.
+        // Add user MOCK_USER1.
         mPermissionMonitor.onUserAdded(MOCK_USER1);
+        // Add SYSTEM_PACKAGE2, expect only have network permission.
         addPackageForUsers(new UserHandle[]{MOCK_USER1}, SYSTEM_PACKAGE2, SYSTEM_APPID1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, SYSTEM_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                SYSTEM_APPID1);
 
         // Add SYSTEM_PACKAGE1, expect permission upgrade.
         addPackageForUsers(new UserHandle[]{MOCK_USER1}, SYSTEM_PACKAGE1, SYSTEM_APPID1);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, SYSTEM_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                SYSTEM_APPID1);
 
+        // Add user MOCK_USER2.
         mPermissionMonitor.onUserAdded(MOCK_USER2);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_APPID1);
 
         // Remove SYSTEM_PACKAGE2, expect keep system permission.
@@ -619,19 +622,19 @@
                 .thenReturn(new String[]{SYSTEM_PACKAGE1});
         removePackageForUsers(new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_PACKAGE2, SYSTEM_APPID1);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_APPID1);
 
         // Add SYSTEM_PACKAGE2, expect keep system permission.
         addPackageForUsers(new UserHandle[]{MOCK_USER1, MOCK_USER2}, SYSTEM_PACKAGE2,
                 SYSTEM_APPID1);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_APPID1);
 
         addPackageForUsers(new UserHandle[]{MOCK_USER1, MOCK_USER2}, MOCK_PACKAGE1, MOCK_APPID1);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_APPID1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 MOCK_APPID1);
 
         // Remove MOCK_PACKAGE1, expect no permission left for all user.
@@ -647,11 +650,12 @@
                 .thenReturn(new String[]{SYSTEM_PACKAGE2});
         removePackageForUsers(new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_PACKAGE1, SYSTEM_APPID1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 SYSTEM_APPID1);
 
         mPermissionMonitor.onUserRemoved(MOCK_USER1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER2}, SYSTEM_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER2},
+                SYSTEM_APPID1);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, SYSTEM_APPID1);
 
         // Remove all packages, expect no permission left.
@@ -866,7 +870,6 @@
 
     @Test
     public void testUpdateUidPermissionsFromSystemConfig() throws Exception {
-        when(mPackageManager.getInstalledPackages(anyInt())).thenReturn(List.of());
         when(mSystemConfigManager.getSystemPermissionUids(eq(INTERNET)))
                 .thenReturn(new int[]{ MOCK_UID1, MOCK_UID2 });
         when(mSystemConfigManager.getSystemPermissionUids(eq(UPDATE_DEVICE_STATS)))
@@ -894,6 +897,7 @@
 
     @Test
     public void testIntentReceiver() throws Exception {
+        mPermissionMonitor.startMonitoring();
         final BroadcastReceiver receiver = expectBroadcastReceiver(
                 Intent.ACTION_PACKAGE_ADDED, Intent.ACTION_PACKAGE_REMOVED);
 
@@ -925,10 +929,10 @@
 
     @Test
     public void testUidsAllowedOnRestrictedNetworksChanged() throws Exception {
+        mPermissionMonitor.startMonitoring();
         final ContentObserver contentObserver = expectRegisterContentObserver(
                 Settings.Global.getUriFor(UIDS_ALLOWED_ON_RESTRICTED_NETWORKS));
 
-        mPermissionMonitor.onUserAdded(MOCK_USER1);
         // Prepare PackageInfo for MOCK_PACKAGE1 and MOCK_PACKAGE2
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE1, MOCK_UID1);
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE2, MOCK_UID2);
@@ -937,14 +941,16 @@
         // should have SYSTEM permission.
         when(mDeps.getUidsAllowedOnRestrictedNetworks(any())).thenReturn(Set.of(MOCK_UID1));
         contentObserver.onChange(true /* selfChange */);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, MOCK_APPID2);
 
         // MOCK_UID2 is listed in setting that allow to use restricted networks, MOCK_UID2
         // should have SYSTEM permission but MOCK_UID1 should revoke permission.
         when(mDeps.getUidsAllowedOnRestrictedNetworks(any())).thenReturn(Set.of(MOCK_UID2));
         contentObserver.onChange(true /* selfChange */);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID2);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID2);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
 
         // No uid lists in setting, should revoke permission from all uids.
@@ -955,27 +961,30 @@
 
     @Test
     public void testUidsAllowedOnRestrictedNetworksChangedWithSharedUid() throws Exception {
+        mPermissionMonitor.startMonitoring();
         final ContentObserver contentObserver = expectRegisterContentObserver(
                 Settings.Global.getUriFor(UIDS_ALLOWED_ON_RESTRICTED_NETWORKS));
 
-        mPermissionMonitor.onUserAdded(MOCK_USER1);
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE1, MOCK_UID1, CHANGE_NETWORK_STATE);
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE2, MOCK_UID1);
 
         // MOCK_PACKAGE1 have CHANGE_NETWORK_STATE, MOCK_UID1 should have NETWORK permission.
         addPackageForUsers(new UserHandle[]{MOCK_USER1}, MOCK_PACKAGE1, MOCK_APPID1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
 
         // MOCK_UID1 is listed in setting that allow to use restricted networks, MOCK_UID1
         // should upgrade to SYSTEM permission.
         when(mDeps.getUidsAllowedOnRestrictedNetworks(any())).thenReturn(Set.of(MOCK_UID1));
         contentObserver.onChange(true /* selfChange */);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
 
         // No app lists in setting, MOCK_UID1 should downgrade to NETWORK permission.
         when(mDeps.getUidsAllowedOnRestrictedNetworks(any())).thenReturn(Set.of());
         contentObserver.onChange(true /* selfChange */);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
 
         // MOCK_PACKAGE1 removed, should revoke permission from MOCK_UID1.
         when(mPackageManager.getPackagesForUid(MOCK_UID1)).thenReturn(new String[]{MOCK_PACKAGE2});
@@ -985,11 +994,10 @@
 
     @Test
     public void testUidsAllowedOnRestrictedNetworksChangedWithMultipleUsers() throws Exception {
+        mPermissionMonitor.startMonitoring();
         final ContentObserver contentObserver = expectRegisterContentObserver(
                 Settings.Global.getUriFor(UIDS_ALLOWED_ON_RESTRICTED_NETWORKS));
 
-        // One user MOCK_USER1
-        mPermissionMonitor.onUserAdded(MOCK_USER1);
         // Prepare PackageInfo for MOCK_PACKAGE1 and MOCK_PACKAGE2.
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE1, MOCK_UID1);
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE2, MOCK_UID2);
@@ -998,14 +1006,15 @@
         // should have SYSTEM permission and MOCK_UID2 has no permissions.
         when(mDeps.getUidsAllowedOnRestrictedNetworks(any())).thenReturn(Set.of(MOCK_UID1));
         contentObserver.onChange(true /* selfChange */);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, MOCK_APPID2);
 
         // Add user MOCK_USER2.
         mPermissionMonitor.onUserAdded(MOCK_USER2);
         // MOCK_APPID1 in both users should all have SYSTEM permission and MOCK_APPID2 has no
         // permissions in either user.
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 MOCK_APPID1);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1, MOCK_USER2}, MOCK_APPID2);
 
@@ -1014,13 +1023,14 @@
         // user.
         when(mDeps.getUidsAllowedOnRestrictedNetworks(any())).thenReturn(Set.of(MOCK_UID2));
         contentObserver.onChange(true /* selfChange */);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1, MOCK_USER2},
                 MOCK_APPID2);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1, MOCK_USER2}, MOCK_APPID1);
 
         // Remove user MOCK_USER1
         mPermissionMonitor.onUserRemoved(MOCK_USER1);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER2}, MOCK_APPID2);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER2},
+                MOCK_APPID2);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER2}, MOCK_APPID1);
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, MOCK_APPID2);
 
@@ -1032,12 +1042,8 @@
 
     @Test
     public void testOnExternalApplicationsAvailable() throws Exception {
-        final BroadcastReceiver receiver = expectBroadcastReceiver(
-                Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
-
         // Initial the permission state. MOCK_PACKAGE1 and MOCK_PACKAGE2 are installed on external
         // and have different uids. There has no permission for both uids.
-        when(mUserManager.getUserHandles(eq(true))).thenReturn(List.of(MOCK_USER1));
         when(mPackageManager.getInstalledPackages(eq(GET_PERMISSIONS | MATCH_ANY_USER))).thenReturn(
                 List.of(buildPackageInfo(MOCK_PACKAGE1, MOCK_UID1),
                         buildPackageInfo(MOCK_PACKAGE2, MOCK_UID2)));
@@ -1045,6 +1051,8 @@
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, MOCK_APPID1, MOCK_APPID2);
         mNetdMonitor.expectTrafficPerm(PERMISSION_NONE, MOCK_APPID1, MOCK_APPID2);
 
+        final BroadcastReceiver receiver = expectBroadcastReceiver(
+                Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
         // Verify receiving EXTERNAL_APPLICATIONS_AVAILABLE intent and update permission to netd.
         final Intent externalIntent = new Intent(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
         externalIntent.putExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST,
@@ -1054,8 +1062,10 @@
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE2, MOCK_UID2, CHANGE_NETWORK_STATE,
                 UPDATE_DEVICE_STATS);
         receiver.onReceive(mContext, externalIntent);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, MOCK_APPID2);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID2);
         mNetdMonitor.expectTrafficPerm(PERMISSION_INTERNET, MOCK_APPID1);
         mNetdMonitor.expectTrafficPerm(PERMISSION_UPDATE_DEVICE_STATS, MOCK_APPID2);
     }
@@ -1063,12 +1073,10 @@
     @Test
     public void testOnExternalApplicationsAvailable_AppsNotRegisteredOnStartMonitoring()
             throws Exception {
+        mPermissionMonitor.startMonitoring();
         final BroadcastReceiver receiver = expectBroadcastReceiver(
                 Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
 
-        // One user MOCK_USER1
-        mPermissionMonitor.onUserAdded(MOCK_USER1);
-
         // Initial the permission state. MOCK_PACKAGE1 and MOCK_PACKAGE2 are installed on external
         // and have different uids. There has no permission for both uids.
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE1, MOCK_UID1,
@@ -1081,8 +1089,10 @@
         externalIntent.putExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST,
                 new String[] { MOCK_PACKAGE1 , MOCK_PACKAGE2});
         receiver.onReceive(mContext, externalIntent);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, MOCK_APPID2);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID2);
         mNetdMonitor.expectTrafficPerm(PERMISSION_INTERNET, MOCK_APPID1);
         mNetdMonitor.expectTrafficPerm(PERMISSION_UPDATE_DEVICE_STATS, MOCK_APPID2);
     }
@@ -1090,12 +1100,8 @@
     @Test
     public void testOnExternalApplicationsAvailableWithSharedUid()
             throws Exception {
-        final BroadcastReceiver receiver = expectBroadcastReceiver(
-                Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
-
         // Initial the permission state. MOCK_PACKAGE1 and MOCK_PACKAGE2 are installed on external
         // storage and shared on MOCK_UID1. There has no permission for MOCK_UID1.
-        when(mUserManager.getUserHandles(eq(true))).thenReturn(List.of(MOCK_USER1));
         when(mPackageManager.getInstalledPackages(eq(GET_PERMISSIONS | MATCH_ANY_USER))).thenReturn(
                 List.of(buildPackageInfo(MOCK_PACKAGE1, MOCK_UID1),
                         buildPackageInfo(MOCK_PACKAGE2, MOCK_UID1)));
@@ -1103,34 +1109,36 @@
         mNetdMonitor.expectNoNetworkPerm(new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
         mNetdMonitor.expectTrafficPerm(PERMISSION_NONE, MOCK_APPID1);
 
+        final BroadcastReceiver receiver = expectBroadcastReceiver(
+                Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
         // Verify receiving EXTERNAL_APPLICATIONS_AVAILABLE intent and update permission to netd.
         final Intent externalIntent = new Intent(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
         externalIntent.putExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST, new String[] {MOCK_PACKAGE1});
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE1, MOCK_UID1, CHANGE_NETWORK_STATE);
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE2, MOCK_UID1, UPDATE_DEVICE_STATS);
         receiver.onReceive(mContext, externalIntent);
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
         mNetdMonitor.expectTrafficPerm(PERMISSION_UPDATE_DEVICE_STATS, MOCK_APPID1);
     }
 
     @Test
     public void testOnExternalApplicationsAvailableWithSharedUid_DifferentStorage()
             throws Exception {
-        final BroadcastReceiver receiver = expectBroadcastReceiver(
-                Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
-
         // Initial the permission state. MOCK_PACKAGE1 is installed on external storage and
         // MOCK_PACKAGE2 is installed on device. These two packages are shared on MOCK_UID1.
         // MOCK_UID1 has NETWORK and INTERNET permissions.
-        when(mUserManager.getUserHandles(eq(true))).thenReturn(List.of(MOCK_USER1));
         when(mPackageManager.getInstalledPackages(eq(GET_PERMISSIONS | MATCH_ANY_USER))).thenReturn(
                 List.of(buildPackageInfo(MOCK_PACKAGE1, MOCK_UID1),
                         buildPackageInfo(MOCK_PACKAGE2, MOCK_UID1, CHANGE_NETWORK_STATE,
                                 INTERNET)));
         mPermissionMonitor.startMonitoring();
-        mNetdMonitor.expectNetworkPerm(NETWORK, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_NETWORK, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
         mNetdMonitor.expectTrafficPerm(PERMISSION_INTERNET, MOCK_APPID1);
 
+        final BroadcastReceiver receiver = expectBroadcastReceiver(
+                Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
         // Verify receiving EXTERNAL_APPLICATIONS_AVAILABLE intent and update permission to netd.
         final Intent externalIntent = new Intent(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
         externalIntent.putExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST, new String[] {MOCK_PACKAGE1});
@@ -1139,7 +1147,21 @@
         buildAndMockPackageInfoWithPermissions(MOCK_PACKAGE2, MOCK_UID1, CHANGE_NETWORK_STATE,
                 INTERNET);
         receiver.onReceive(mContext, externalIntent);
-        mNetdMonitor.expectNetworkPerm(SYSTEM, new UserHandle[]{MOCK_USER1}, MOCK_APPID1);
+        mNetdMonitor.expectNetworkPerm(PERMISSION_SYSTEM, new UserHandle[]{MOCK_USER1},
+                MOCK_APPID1);
         mNetdMonitor.expectTrafficPerm(PERMISSION_TRAFFIC_ALL, MOCK_APPID1);
     }
+
+    @Test
+    public void testIsHigherNetworkPermission() {
+        assertFalse(isHigherNetworkPermission(PERMISSION_NONE, PERMISSION_NONE));
+        assertFalse(isHigherNetworkPermission(PERMISSION_NONE, PERMISSION_NETWORK));
+        assertFalse(isHigherNetworkPermission(PERMISSION_NONE, PERMISSION_SYSTEM));
+        assertTrue(isHigherNetworkPermission(PERMISSION_NETWORK, PERMISSION_NONE));
+        assertFalse(isHigherNetworkPermission(PERMISSION_NETWORK, PERMISSION_NETWORK));
+        assertFalse(isHigherNetworkPermission(PERMISSION_NETWORK, PERMISSION_SYSTEM));
+        assertTrue(isHigherNetworkPermission(PERMISSION_SYSTEM, PERMISSION_NONE));
+        assertTrue(isHigherNetworkPermission(PERMISSION_SYSTEM, PERMISSION_NETWORK));
+        assertFalse(isHigherNetworkPermission(PERMISSION_SYSTEM, PERMISSION_SYSTEM));
+    }
 }