Add hidden constants for communicating about local network agents

Test: FrameworksNetTests
Change-Id: Ic490fee6ee70d74acff0a290199b2946817173d0

framework/src/android/net/NetworkCapabilities.java

@@ -453,6 +453,7 @@ public final class NetworkCapabilities implements Parcelable {
             NET_CAPABILITY_MMTEL,
             NET_CAPABILITY_PRIORITIZE_LATENCY,
             NET_CAPABILITY_PRIORITIZE_BANDWIDTH,
+            NET_CAPABILITY_LOCAL_NETWORK,
     })
     public @interface NetCapability { }
 
@@ -714,7 +715,21 @@ public final class NetworkCapabilities implements Parcelable {
      */
     public static final int NET_CAPABILITY_PRIORITIZE_BANDWIDTH = 35;
 
-    private static final int MAX_NET_CAPABILITY = NET_CAPABILITY_PRIORITIZE_BANDWIDTH;
+    /**
+     * This is a local network, e.g. a tethering downstream or a P2P direct network.
+     *
+     * <p>
+     * Note that local networks are not sent to callbacks by default. To receive callbacks about
+     * them, the {@link NetworkRequest} instance must be prepared to see them, either by
+     * adding the capability with {@link NetworkRequest.Builder#addCapability}, by removing
+     * this forbidden capability with {@link NetworkRequest.Builder#removeForbiddenCapability},
+     * or by clearing all capabilites with {@link NetworkRequest.Builder#clearCapabilities()}.
+     * </p>
+     * @hide
+     */
+    public static final int NET_CAPABILITY_LOCAL_NETWORK = 36;
+
+    private static final int MAX_NET_CAPABILITY = NET_CAPABILITY_LOCAL_NETWORK;
 
     // Set all bits up to the MAX_NET_CAPABILITY-th bit
     private static final long ALL_VALID_CAPABILITIES = (2L << MAX_NET_CAPABILITY) - 1;
@@ -859,7 +874,7 @@ public final class NetworkCapabilities implements Parcelable {
     }
 
     /**
-     * Removes (if found) the given forbidden capability from this {@code NetworkCapability}
+     * Removes (if found) the given forbidden capability from this {@link NetworkCapabilities}
      * instance that were added via addForbiddenCapability(int) or setCapabilities(int[], int[]).
      *
      * @param capability the capability to be removed.
@@ -872,6 +887,16 @@ public final class NetworkCapabilities implements Parcelable {
         return this;
     }
 
+    /**
+     * Removes all forbidden capabilities from this {@link NetworkCapabilities} instance.
+     * @return This NetworkCapabilities instance, to facilitate chaining.
+     * @hide
+     */
+    public @NonNull NetworkCapabilities removeAllForbiddenCapabilities() {
+        mForbiddenNetworkCapabilities = 0;
+        return this;
+    }
+
     /**
      * Sets (or clears) the given capability on this {@link NetworkCapabilities}
      * instance.
@@ -1039,11 +1064,12 @@ public final class NetworkCapabilities implements Parcelable {
     }
 
     /**
-     * Check if this NetworkCapabilities has system managed capabilities or not.
+     * Check if this NetworkCapabilities has connectivity-managed capabilities or not.
      * @hide
      */
     public boolean hasConnectivityManagedCapability() {
-        return ((mNetworkCapabilities & CONNECTIVITY_MANAGED_CAPABILITIES) != 0);
+        return (mNetworkCapabilities & CONNECTIVITY_MANAGED_CAPABILITIES) != 0
+                || mForbiddenNetworkCapabilities != 0;
     }
 
     /**
@@ -2523,6 +2549,7 @@ public final class NetworkCapabilities implements Parcelable {
             case NET_CAPABILITY_MMTEL:                return "MMTEL";
             case NET_CAPABILITY_PRIORITIZE_LATENCY:          return "PRIORITIZE_LATENCY";
             case NET_CAPABILITY_PRIORITIZE_BANDWIDTH:        return "PRIORITIZE_BANDWIDTH";
+            case NET_CAPABILITY_LOCAL_NETWORK:        return "LOCAL_NETWORK";
             default:                                  return Integer.toString(capability);
         }
     }

framework/src/android/net/NetworkRequest.java

@@ -20,6 +20,7 @@ import static android.net.NetworkCapabilities.NET_CAPABILITY_CAPTIVE_PORTAL;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_DUN;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_FOREGROUND;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET;
+import static android.net.NetworkCapabilities.NET_CAPABILITY_LOCAL_NETWORK;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_CONGESTED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_METERED;
 import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED;
@@ -283,6 +284,15 @@ public class NetworkRequest implements Parcelable {
                 NET_CAPABILITY_TRUSTED,
                 NET_CAPABILITY_VALIDATED);
 
+        /**
+         * Capabilities that are forbidden by default.
+         * Forbidden capabilities only make sense in NetworkRequest, not for network agents.
+         * Therefore these capabilities are only in NetworkRequest.
+         */
+        private static final int[] DEFAULT_FORBIDDEN_CAPABILITIES = new int[] {
+            NET_CAPABILITY_LOCAL_NETWORK
+        };
+
         private final NetworkCapabilities mNetworkCapabilities;
 
         // A boolean that represents whether the NOT_VCN_MANAGED capability should be deduced when
@@ -298,6 +308,16 @@ public class NetworkRequest implements Parcelable {
             // it for apps that do not have the NETWORK_SETTINGS permission.
             mNetworkCapabilities = new NetworkCapabilities();
             mNetworkCapabilities.setSingleUid(Process.myUid());
+            // Default forbidden capabilities are foremost meant to help with backward
+            // compatibility. When adding new types of network identified by a capability that
+            // might confuse older apps, a default forbidden capability will have apps not see
+            // these networks unless they explicitly ask for it.
+            // If the app called clearCapabilities() it will see everything, but then it
+            // can be argued that it's fair to send them too, since it asked for everything
+            // explicitly.
+            for (final int forbiddenCap : DEFAULT_FORBIDDEN_CAPABILITIES) {
+                mNetworkCapabilities.addForbiddenCapability(forbiddenCap);
+            }
         }
 
         /**

framework/src/android/net/NetworkScore.java

@@ -45,7 +45,8 @@ public final class NetworkScore implements Parcelable {
     @IntDef(value = {
             KEEP_CONNECTED_NONE,
             KEEP_CONNECTED_FOR_HANDOVER,
-            KEEP_CONNECTED_FOR_TEST
+            KEEP_CONNECTED_FOR_TEST,
+            KEEP_CONNECTED_DOWNSTREAM_NETWORK
     })
     public @interface KeepConnectedReason { }
 
@@ -64,6 +65,12 @@ public final class NetworkScore implements Parcelable {
      * @hide
      */
     public static final int KEEP_CONNECTED_FOR_TEST = 2;
+    /**
+     * Keep this network connected even if there is no outstanding request for it, because
+     * it is a downstream network.
+     * @hide
+     */
+    public static final int KEEP_CONNECTED_DOWNSTREAM_NETWORK = 3;
 
     // Agent-managed policies
     // This network should lose to a wifi that has ever been validated