[VCN13] Implement tracking best matching network

This is done by:
  1. In requestNetwork, provide a basic permission check.
  2. rematchNetworksAndRequests: no change, since non listen
     requests will be automatically processed to track
     best satisfying network.
  3. applyNetworkReassignment: no change, since non-request
     will not be sent to factories.

Test: atest ConnectivityServiceTest#testRegisterBestMatchingNetworkCallback_noIssueToFactory
Test: atest ConnectivityServiceTest#testRegisterBestMatchingNetworkCallback_trackBestNetwork
Bug: 175662146
Change-Id: I8cf4ab334df6812d84cdda160e9b72b6f54062af

1 files changed, 97 insertions, 5 deletions

diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index cc58edf80e88..b894b02c0a05 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -1079,6 +1079,10 @@ public class ConnectivityServiceTest {
         public void triggerUnfulfillable(NetworkRequest r) {
             super.releaseRequestAsUnfulfillableByAnyFactory(r);
         }
+
+        public void assertNoRequestChanged() {
+            assertNull(mRequestHistory.poll(0, r -> true));
+        }
     }
 
     private Set<UidRange> uidRangesForUids(int... uids) {
@@ -11121,11 +11125,99 @@ public class ConnectivityServiceTest {
         mCm.unregisterNetworkCallback(cellCb);
     }
 
+    // Cannot be part of MockNetworkFactory since it requires method of the test.
+    private void expectNoRequestChanged(@NonNull MockNetworkFactory factory) {
+        waitForIdle();
+        factory.assertNoRequestChanged();
+    }
+
     @Test
-    public void testRegisterBestMatchingNetworkCallback() throws Exception {
-        final NetworkRequest request = new NetworkRequest.Builder().build();
-        assertThrows(UnsupportedOperationException.class,
-                () -> mCm.registerBestMatchingNetworkCallback(request, new NetworkCallback(),
-                        mCsHandlerThread.getThreadHandler()));
+    public void testRegisterBestMatchingNetworkCallback_noIssueToFactory() throws Exception {
+        // Prepare mock mms factory.
+        final HandlerThread handlerThread = new HandlerThread("MockCellularFactory");
+        handlerThread.start();
+        NetworkCapabilities filter = new NetworkCapabilities()
+                .addTransportType(TRANSPORT_CELLULAR)
+                .addCapability(NET_CAPABILITY_MMS);
+        final MockNetworkFactory testFactory = new MockNetworkFactory(handlerThread.getLooper(),
+                mServiceContext, "testFactory", filter, mCsHandlerThread);
+        testFactory.setScoreFilter(40);
+
+        try {
+            // Register the factory and expect it will see default request, because all requests
+            // are sent to all factories.
+            testFactory.register();
+            testFactory.expectRequestAdd();
+            testFactory.assertRequestCountEquals(1);
+            // The factory won't try to start the network since the default request doesn't
+            // match the filter (no INTERNET capability).
+            assertFalse(testFactory.getMyStartRequested());
+
+            // Register callback for listening best matching network. Verify that the request won't
+            // be sent to factory.
+            final TestNetworkCallback bestMatchingCb = new TestNetworkCallback();
+            mCm.registerBestMatchingNetworkCallback(
+                    new NetworkRequest.Builder().addCapability(NET_CAPABILITY_MMS).build(),
+                    bestMatchingCb, mCsHandlerThread.getThreadHandler());
+            bestMatchingCb.assertNoCallback();
+            expectNoRequestChanged(testFactory);
+            testFactory.assertRequestCountEquals(1);
+            assertFalse(testFactory.getMyStartRequested());
+
+            // Fire a normal mms request, verify the factory will only see the request.
+            final TestNetworkCallback mmsNetworkCallback = new TestNetworkCallback();
+            final NetworkRequest mmsRequest = new NetworkRequest.Builder()
+                    .addCapability(NET_CAPABILITY_MMS).build();
+            mCm.requestNetwork(mmsRequest, mmsNetworkCallback);
+            testFactory.expectRequestAdd();
+            testFactory.assertRequestCountEquals(2);
+            assertTrue(testFactory.getMyStartRequested());
+
+            // Unregister best matching callback, verify factory see no change.
+            mCm.unregisterNetworkCallback(bestMatchingCb);
+            expectNoRequestChanged(testFactory);
+            testFactory.assertRequestCountEquals(2);
+            assertTrue(testFactory.getMyStartRequested());
+        } finally {
+            testFactory.terminate();
+        }
+    }
+
+    @Test
+    public void testRegisterBestMatchingNetworkCallback_trackBestNetwork() throws Exception {
+        final TestNetworkCallback bestMatchingCb = new TestNetworkCallback();
+        mCm.registerBestMatchingNetworkCallback(
+                new NetworkRequest.Builder().addCapability(NET_CAPABILITY_TRUSTED).build(),
+                bestMatchingCb, mCsHandlerThread.getThreadHandler());
+
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+        mCellNetworkAgent.connect(true);
+        bestMatchingCb.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connect(true);
+        bestMatchingCb.expectAvailableDoubleValidatedCallbacks(mWiFiNetworkAgent);
+
+        // Change something on cellular to trigger capabilities changed, since the callback
+        // only cares about the best network, verify it received nothing from cellular.
+        mCellNetworkAgent.addCapability(NET_CAPABILITY_TEMPORARILY_NOT_METERED);
+        bestMatchingCb.assertNoCallback();
+
+        // Make cellular the best network again, verify the callback now tracks cellular.
+        mWiFiNetworkAgent.adjustScore(-50);
+        bestMatchingCb.expectAvailableCallbacksValidated(mCellNetworkAgent);
+
+        // Make cellular temporary non-trusted, which will not satisfying the request.
+        // Verify the callback switch from/to the other network accordingly.
+        mCellNetworkAgent.removeCapability(NET_CAPABILITY_TRUSTED);
+        bestMatchingCb.expectAvailableCallbacksValidated(mWiFiNetworkAgent);
+        mCellNetworkAgent.addCapability(NET_CAPABILITY_TRUSTED);
+        bestMatchingCb.expectAvailableDoubleValidatedCallbacks(mCellNetworkAgent);
+
+        // Verify the callback doesn't care about wifi disconnect.
+        mWiFiNetworkAgent.disconnect();
+        bestMatchingCb.assertNoCallback();
+        mCellNetworkAgent.disconnect();
+        bestMatchingCb.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
     }
 }