[NS05] Feed network offer callbacks

The design is very simply expressed :
An offer is needed for a request if and only if that offer
might beat the satisfier for that request.

The implementation of "might beat" is NetworkRanker#mightBeat.

Test: FrameworksNetTests FrameworksWifiTests NetworkStackTests
Bug: 167544279
Merged-In: I3c2563d4ae4e3715d0c6270344ba8f7ef067872f
Merged-In: I0fe911eef2483ecbac48c733d56283b81538690a
Change-Id: I0fe911eef2483ecbac48c733d56283b81538690a
  (cherry-picked from 7b6a33bd50)

framework/api/system-current.txt

@@ -316,9 +316,16 @@ package android.net {
     method public int getProviderId();
     method public void onNetworkRequestWithdrawn(@NonNull android.net.NetworkRequest);
     method public void onNetworkRequested(@NonNull android.net.NetworkRequest, @IntRange(from=0, to=99) int, int);
+    method @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY) public void registerNetworkOffer(@NonNull android.net.NetworkScore, @NonNull android.net.NetworkCapabilities, @NonNull java.util.concurrent.Executor, @NonNull android.net.NetworkProvider.NetworkOfferCallback);
+    method @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY) public void unregisterNetworkOffer(@NonNull android.net.NetworkProvider.NetworkOfferCallback);
     field public static final int ID_NONE = -1; // 0xffffffff
   }
 
+  public static interface NetworkProvider.NetworkOfferCallback {
+    method public void onNetworkNeeded(@NonNull android.net.NetworkRequest);
+    method public void onNetworkUnneeded(@NonNull android.net.NetworkRequest);
+  }
+
   public class NetworkReleasedException extends java.lang.Exception {
   }
 

framework/src/android/net/ConnectivityManager.java

@@ -3360,7 +3360,7 @@ public class ConnectivityManager {
      * @param score The prospective score of the network.
      * @param caps The prospective capabilities of the network.
      * @param callback The callback to call when this offer is needed or unneeded.
-     * @hide
+     * @hide exposed via the NetworkProvider class.
      */
     @RequiresPermission(anyOf = {
             NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
@@ -3383,7 +3383,7 @@ public class ConnectivityManager {
      *
      * @param callback The callback passed at registration time. This must be the same object
      *                 that was passed to {@link #offerNetwork}
-     * @hide
+     * @hide exposed via the NetworkProvider class.
      */
     public void unofferNetwork(@NonNull final INetworkOfferCallback callback) {
         try {

framework/src/android/net/INetworkOfferCallback.aidl

@@ -51,10 +51,8 @@ oneway interface INetworkOfferCallback {
     /**
      * Called when a network for this offer is needed to fulfill this request.
      * @param networkRequest the request to satisfy
-     * @param providerId the ID of the provider currently satisfying
-     *          this request, or NetworkProvider.ID_NONE if none.
      */
-    void onNetworkNeeded(in NetworkRequest networkRequest, int providerId);
+    void onNetworkNeeded(in NetworkRequest networkRequest);
 
     /**
      * Informs the registrant that the offer is no longer valuable to fulfill this request.

framework/src/android/net/NetworkProvider.java

@@ -168,12 +168,16 @@ public class NetworkProvider {
     }
 
     /** @hide */
-    // TODO : make @SystemApi when the impl is complete
+    @SystemApi
     public interface NetworkOfferCallback {
-        /** Called by the system when a network for this offer is needed to satisfy some
+        /**
-         *  networking request. */
+         * Called by the system when a network for this offer is needed to satisfy some
-        void onNetworkNeeded(@NonNull NetworkRequest request, int providerId);
+         * networking request.
-        /** Called by the system when this offer is no longer valuable for this request. */
+         */
+        void onNetworkNeeded(@NonNull NetworkRequest request);
+        /**
+         * Called by the system when this offer is no longer valuable for this request.
+         */
         void onNetworkUnneeded(@NonNull NetworkRequest request);
     }
 
@@ -188,9 +192,8 @@ public class NetworkProvider {
         }
 
         @Override
-        public void onNetworkNeeded(final @NonNull NetworkRequest request,
+        public void onNetworkNeeded(final @NonNull NetworkRequest request) {
-                final int providerId) {
+            mExecutor.execute(() -> callback.onNetworkNeeded(request));
-            mExecutor.execute(() -> callback.onNetworkNeeded(request, providerId));
         }
 
         @Override
@@ -254,8 +257,11 @@ public class NetworkProvider {
      *
      * The capabilities and score act as filters as to what requests the provider will see.
      * They are not promises, but for best performance, the providers should strive to put
-     * as much known information as possible in the offer. For capabilities in particular, it
+     * as much known information as possible in the offer. For the score, it should put as
-     * should put all NetworkAgent-managed capabilities a network may have, even if it doesn't
+     * strong a score as the networks will have, since this will filter what requests the
+     * provider sees – it's not a promise, it only serves to avoid sending requests that
+     * the provider can't ever hope to satisfy better than any current network. For capabilities,
+     * it should put all NetworkAgent-managed capabilities a network may have, even if it doesn't
      * have them at first. This applies to INTERNET, for example ; if a provider thinks the
      * network it can bring up for this offer may offer Internet access it should include the
      * INTERNET bit. It's fine if the brought up network ends up not actually having INTERNET.
@@ -268,9 +274,9 @@ public class NetworkProvider {
      *
      * @hide
      */
-    // TODO : make @SystemApi when the impl is complete
+    @SystemApi
     @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY)
-    public void offerNetwork(@NonNull final NetworkScore score,
+    public void registerNetworkOffer(@NonNull final NetworkScore score,
             @NonNull final NetworkCapabilities caps, @NonNull final Executor executor,
             @NonNull final NetworkOfferCallback callback) {
         // Can't offer a network with a provider that is not yet registered or already unregistered.
@@ -307,9 +313,9 @@ public class NetworkProvider {
      *
      * @hide
      */
-    // TODO : make @SystemApi when the impl is complete
+    @SystemApi
     @RequiresPermission(android.Manifest.permission.NETWORK_FACTORY)
-    public void unofferNetwork(final @NonNull NetworkOfferCallback callback) {
+    public void unregisterNetworkOffer(final @NonNull NetworkOfferCallback callback) {
         final NetworkOfferCallbackProxy proxy = findProxyForCallback(callback);
         if (null == proxy) return;
         mProxies.remove(proxy);

service/src/com/android/server/ConnectivityService.java

@@ -3359,8 +3359,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 nai.lastValidated = valid;
                 nai.everValidated |= valid;
                 updateCapabilities(oldScore, nai, nai.networkCapabilities);
-                // If score has changed, rebroadcast to NetworkProviders. b/17726566
-                if (oldScore != nai.getCurrentScore()) sendUpdatedScoreToFactories(nai);
                 if (valid) {
                     handleFreshlyValidatedNetwork(nai);
                     // Clear NO_INTERNET, PRIVATE_DNS_BROKEN, PARTIAL_CONNECTIVITY and
@@ -3781,9 +3779,12 @@ public class ConnectivityService extends IConnectivityManager.Stub
             if (currentNetwork != null
                     && currentNetwork.network.getNetId() == nai.network.getNetId()) {
                 // uid rules for this network will be removed in destroyNativeNetwork(nai).
+                // TODO : setting the satisfier is in fact the job of the rematch. Teach the
+                // rematch not to keep disconnected agents instead of setting it here ; this
+                // will also allow removing updating the offers below.
                 nri.setSatisfier(null, null);
-                if (request.isRequest()) {
+                for (final NetworkOfferInfo noi : mNetworkOffers) {
-                    sendUpdatedScoreToFactories(request, null);
+                    informOffer(nri, noi.offer, mNetworkRanker);
                 }
 
                 if (mDefaultRequest == nri) {
@@ -3939,16 +3940,13 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
 
         rematchAllNetworksAndRequests();
-        for (final NetworkRequestInfo nri : nris) {
-            // If the nri is satisfied, return as its score has already been sent if needed.
-            if (nri.isBeingSatisfied()) {
-                return;
-            }
 
-            // As this request was not satisfied on rematch and thus never had any scores sent to
+        // Requests that have not been matched to a network will not have been sent to the
-            // the factories, send null now for each request of type REQUEST.
+        // providers, because the old satisfier and the new satisfier are the same (null in this
-            for (final NetworkRequest req : nri.mRequests) {
+        // case). Send these requests to the providers.
-                if (req.isRequest()) sendUpdatedScoreToFactories(req, null);
+        for (final NetworkRequestInfo nri : nris) {
+            for (final NetworkOfferInfo noi : mNetworkOffers) {
+                informOffer(nri, noi.offer, mNetworkRanker);
             }
         }
     }
@@ -4156,7 +4154,15 @@ public class ConnectivityService extends IConnectivityManager.Stub
             }
         }
 
-        cancelNpiRequests(nri);
+        // For all outstanding offers, cancel any of the layers of this NRI that used to be
+        // needed for this offer.
+        for (final NetworkOfferInfo noi : mNetworkOffers) {
+            for (final NetworkRequest req : nri.mRequests) {
+                if (req.isRequest() && noi.offer.neededFor(req)) {
+                    noi.offer.onNetworkUnneeded(req);
+                }
+            }
+        }
     }
 
     private void handleRemoveNetworkRequests(@NonNull final Set<NetworkRequestInfo> nris) {
@@ -4169,20 +4175,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
     }
 
-    private void cancelNpiRequests(@NonNull final NetworkRequestInfo nri) {
-        for (final NetworkRequest req : nri.mRequests) {
-            cancelNpiRequest(req);
-        }
-    }
-
-    private void cancelNpiRequest(@NonNull final NetworkRequest req) {
-        if (req.isRequest()) {
-            for (final NetworkProviderInfo npi : mNetworkProviderInfos.values()) {
-                npi.cancelRequest(req);
-            }
-        }
-    }
-
     private void removeListenRequestFromNetworks(@NonNull final NetworkRequest req) {
         // listens don't have a singular affected Network. Check all networks to see
         // if this listen request applies and remove it.
@@ -4309,7 +4301,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
             nai.networkAgentConfig.acceptPartialConnectivity = accept;
             nai.updateScoreForNetworkAgentConfigUpdate();
             rematchAllNetworksAndRequests();
-            sendUpdatedScoreToFactories(nai);
         }
 
         if (always) {
@@ -4377,7 +4368,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
         if (!nai.avoidUnvalidated) {
             nai.avoidUnvalidated = true;
             rematchAllNetworksAndRequests();
-            sendUpdatedScoreToFactories(nai);
         }
     }
 
@@ -4482,14 +4472,9 @@ public class ConnectivityService extends IConnectivityManager.Stub
         return avoidBadWifi();
     }
 
-
+    // TODO : this function is now useless.
     private void rematchForAvoidBadWifiUpdate() {
         rematchAllNetworksAndRequests();
-        for (NetworkAgentInfo nai: mNetworkAgentInfos) {
-            if (nai.networkCapabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
-                sendUpdatedScoreToFactories(nai);
-            }
-        }
     }
 
     // TODO: Evaluate whether this is of interest to other consumers of
@@ -5514,24 +5499,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
             }
         }
 
-        void sendMessageToNetworkProvider(int what, int arg1, int arg2, Object obj) {
-            try {
-                messenger.send(Message.obtain(null /* handler */, what, arg1, arg2, obj));
-            } catch (RemoteException e) {
-                // Remote process died. Ignore; the death recipient will remove this
-                // NetworkProviderInfo from mNetworkProviderInfos.
-            }
-        }
-
-        void requestNetwork(NetworkRequest request, int score, int servingProviderId) {
-            sendMessageToNetworkProvider(NetworkProvider.CMD_REQUEST_NETWORK, score,
-                            servingProviderId, request);
-        }
-
-        void cancelRequest(NetworkRequest request) {
-            sendMessageToNetworkProvider(NetworkProvider.CMD_CANCEL_REQUEST, 0, 0, request);
-        }
-
         void connect(Context context, Handler handler) {
             try {
                 messenger.getBinder().linkToDeath(mDeathRecipient, 0);
@@ -6240,7 +6207,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
         if (DBG) log("Got NetworkProvider Messenger for " + npi.name);
         mNetworkProviderInfos.put(npi.messenger, npi);
         npi.connect(mContext, mTrackerHandler);
-        sendAllRequestsToProvider(npi);
     }
 
     @Override
@@ -6263,6 +6229,9 @@ public class ConnectivityService extends IConnectivityManager.Stub
     public void offerNetwork(final int providerId,
             @NonNull final NetworkScore score, @NonNull final NetworkCapabilities caps,
             @NonNull final INetworkOfferCallback callback) {
+        Objects.requireNonNull(score);
+        Objects.requireNonNull(caps);
+        Objects.requireNonNull(callback);
         final NetworkOffer offer = new NetworkOffer(
                 FullScore.makeProspectiveScore(score, caps), caps, callback, providerId);
         mHandler.sendMessage(mHandler.obtainMessage(EVENT_REGISTER_NETWORK_OFFER, offer));
@@ -6287,7 +6256,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
                 toRemove.add(noi);
             }
         }
-        for (NetworkOfferInfo noi : toRemove) {
+        for (final NetworkOfferInfo noi : toRemove) {
             handleUnregisterNetworkOffer(noi);
         }
         if (DBG) log("unregisterNetworkProvider for " + npi.name);
@@ -6707,7 +6676,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
             return;
         }
         mNetworkOffers.add(noi);
-        // TODO : send requests to the provider.
+        issueNetworkNeeds(noi);
     }
 
     private void handleUnregisterNetworkOffer(@NonNull final NetworkOfferInfo noi) {
@@ -7482,100 +7451,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
         updateLinkProperties(nai, newLp, new LinkProperties(nai.linkProperties));
     }
 
-    private void sendUpdatedScoreToFactories(NetworkAgentInfo nai) {
-        for (int i = 0; i < nai.numNetworkRequests(); i++) {
-            NetworkRequest nr = nai.requestAt(i);
-            // Don't send listening or track default request to factories. b/17393458
-            if (!nr.isRequest()) continue;
-            sendUpdatedScoreToFactories(nr, nai);
-        }
-    }
-
-    private void sendUpdatedScoreToFactories(
-            @NonNull final NetworkReassignment.RequestReassignment event) {
-        // If a request of type REQUEST is now being satisfied by a new network.
-        if (null != event.mNewNetworkRequest && event.mNewNetworkRequest.isRequest()) {
-            sendUpdatedScoreToFactories(event.mNewNetworkRequest, event.mNewNetwork);
-        }
-
-        // If a previously satisfied request of type REQUEST is no longer being satisfied.
-        if (null != event.mOldNetworkRequest && event.mOldNetworkRequest.isRequest()
-                && event.mOldNetworkRequest != event.mNewNetworkRequest) {
-            sendUpdatedScoreToFactories(event.mOldNetworkRequest, null);
-        }
-
-        cancelMultilayerLowerPriorityNpiRequests(event.mNetworkRequestInfo);
-    }
-
-    /**
-     *  Cancel with all NPIs the given NRI's multilayer requests that are a lower priority than
-     *  its currently satisfied active request.
-     * @param nri the NRI to cancel lower priority requests for.
-     */
-    private void cancelMultilayerLowerPriorityNpiRequests(
-            @NonNull final NetworkRequestInfo nri) {
-        if (!nri.isMultilayerRequest() || null == nri.mActiveRequest) {
-            return;
-        }
-
-        final int indexOfNewRequest = nri.mRequests.indexOf(nri.mActiveRequest);
-        for (int i = indexOfNewRequest + 1; i < nri.mRequests.size(); i++) {
-            cancelNpiRequest(nri.mRequests.get(i));
-        }
-    }
-
-    private void sendUpdatedScoreToFactories(@NonNull NetworkRequest networkRequest,
-            @Nullable NetworkAgentInfo nai) {
-        final int score;
-        final int serial;
-        if (nai != null) {
-            score = nai.getCurrentScore();
-            serial = nai.factorySerialNumber;
-        } else {
-            score = 0;
-            serial = 0;
-        }
-        if (VDBG || DDBG){
-            log("sending new Min Network Score(" + score + "): " + networkRequest.toString());
-        }
-        for (NetworkProviderInfo npi : mNetworkProviderInfos.values()) {
-            npi.requestNetwork(networkRequest, score, serial);
-        }
-    }
-
-    /** Sends all current NetworkRequests to the specified factory. */
-    private void sendAllRequestsToProvider(@NonNull final NetworkProviderInfo npi) {
-        ensureRunningOnConnectivityServiceThread();
-        for (final NetworkRequestInfo nri : getNrisFromGlobalRequests()) {
-            for (final NetworkRequest req : nri.mRequests) {
-                if (!req.isRequest() && nri.getActiveRequest() == req) {
-                    break;
-                }
-                if (!req.isRequest()) {
-                    continue;
-                }
-                // Only set the nai for the request it is satisfying.
-                final NetworkAgentInfo nai =
-                        nri.getActiveRequest() == req ? nri.getSatisfier() : null;
-                final int score;
-                final int serial;
-                if (null != nai) {
-                    score = nai.getCurrentScore();
-                    serial = nai.factorySerialNumber;
-                } else {
-                    score = 0;
-                    serial = NetworkProvider.ID_NONE;
-                }
-                npi.requestNetwork(req, score, serial);
-                // For multilayer requests, don't send lower priority requests if a higher priority
-                // request is already satisfied.
-                if (null != nai) {
-                    break;
-                }
-            }
-        }
-    }
-
     private void sendPendingIntentForRequest(NetworkRequestInfo nri, NetworkAgentInfo networkAgent,
             int notificationType) {
         if (notificationType == ConnectivityManager.CALLBACK_AVAILABLE && !nri.mPendingIntentSent) {
@@ -8067,6 +7942,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
             log(changes.toString()); // Shorter form, only one line of log
         }
         applyNetworkReassignment(changes, now);
+        issueNetworkNeeds();
     }
 
     private void applyNetworkReassignment(@NonNull final NetworkReassignment changes,
@@ -8098,12 +7974,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
         // before LegacyTypeTracker sends legacy broadcasts
         for (final NetworkReassignment.RequestReassignment event :
                 changes.getRequestReassignments()) {
-            // Tell NetworkProviders about the new score, so they can stop
-            // trying to connect if they know they cannot match it.
-            // TODO - this could get expensive if there are a lot of outstanding requests for this
-            // network. Think of a way to reduce this. Push netid->request mapping to each factory?
-            sendUpdatedScoreToFactories(event);
-
             if (null != event.mNewNetwork) {
                 notifyNetworkAvailable(event.mNewNetwork, event.mNetworkRequestInfo);
             } else {
@@ -8240,6 +8110,107 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
     }
 
+    private void issueNetworkNeeds() {
+        ensureRunningOnConnectivityServiceThread();
+        for (final NetworkOfferInfo noi : mNetworkOffers) {
+            issueNetworkNeeds(noi);
+        }
+    }
+
+    private void issueNetworkNeeds(@NonNull final NetworkOfferInfo noi) {
+        ensureRunningOnConnectivityServiceThread();
+        for (final NetworkRequestInfo nri : mNetworkRequests.values()) {
+            informOffer(nri, noi.offer, mNetworkRanker);
+        }
+    }
+
+    /**
+     * Inform a NetworkOffer about any new situation of a request.
+     *
+     * This function handles updates to offers. A number of events may happen that require
+     * updating the registrant for this offer about the situation :
+     * • The offer itself was updated. This may lead the offer to no longer being able
+     *     to satisfy a request or beat a satisfier (and therefore be no longer needed),
+     *     or conversely being strengthened enough to beat the satisfier (and therefore
+     *     start being needed)
+     * • The network satisfying a request changed (including cases where the request
+     *     starts or stops being satisfied). The new network may be a stronger or weaker
+     *     match than the old one, possibly affecting whether the offer is needed.
+     * • The network satisfying a request updated their score. This may lead the offer
+     *     to no longer be able to beat it if the current satisfier got better, or
+     *     conversely start being a good choice if the current satisfier got weaker.
+     *
+     * @param nri The request
+     * @param offer The offer. This may be an updated offer.
+     */
+    private static void informOffer(@NonNull NetworkRequestInfo nri,
+            @NonNull final NetworkOffer offer, @NonNull final NetworkRanker networkRanker) {
+        final NetworkRequest activeRequest = nri.isBeingSatisfied() ? nri.getActiveRequest() : null;
+        final NetworkAgentInfo satisfier = null != activeRequest ? nri.getSatisfier() : null;
+        final FullScore satisfierScore = null != satisfier ? satisfier.getScore() : null;
+
+        // Multi-layer requests have a currently active request, the one being satisfied.
+        // Since the system will try to bring up a better network than is currently satisfying
+        // the request, NetworkProviders need to be told the offers matching the requests *above*
+        // the currently satisfied one are needed, that the ones *below* the satisfied one are
+        // not needed, and the offer is needed for the active request iff the offer can beat
+        // the satisfier.
+        // For non-multilayer requests, the logic above gracefully degenerates to only the
+        // last case.
+        // To achieve this, the loop below will proceed in three steps. In a first phase, inform
+        // providers that the offer is needed for this request, until the active request is found.
+        // In a second phase, deal with the currently active request. In a third phase, inform
+        // the providers that offer is unneeded for the remaining requests.
+
+        // First phase : inform providers of all requests above the active request.
+        int i;
+        for (i = 0; nri.mRequests.size() > i; ++i) {
+            final NetworkRequest request = nri.mRequests.get(i);
+            if (activeRequest == request) break; // Found the active request : go to phase 2
+            if (!request.isRequest()) continue; // Listens/track defaults are never sent to offers
+            // Since this request is higher-priority than the one currently satisfied, if the
+            // offer can satisfy it, the provider should try and bring up the network for sure ;
+            // no need to even ask the ranker – an offer that can satisfy is always better than
+            // no network. Hence tell the provider so unless it already knew.
+            if (request.canBeSatisfiedBy(offer.caps) && !offer.neededFor(request)) {
+                offer.onNetworkNeeded(request);
+            }
+        }
+
+        // Second phase : deal with the active request (if any)
+        if (null != activeRequest && activeRequest.isRequest()) {
+            final boolean oldNeeded = offer.neededFor(activeRequest);
+            // An offer is needed if it is currently served by this provider or if this offer
+            // can beat the current satisfier.
+            final boolean currentlyServing = satisfier != null
+                    && satisfier.factorySerialNumber == offer.providerId;
+            final boolean newNeeded = (currentlyServing
+                    || (activeRequest.canBeSatisfiedBy(offer.caps)
+                            && networkRanker.mightBeat(activeRequest, satisfierScore, offer)));
+            if (newNeeded != oldNeeded) {
+                if (newNeeded) {
+                    offer.onNetworkNeeded(activeRequest);
+                } else {
+                    // The offer used to be able to beat the satisfier. Now it can't.
+                    offer.onNetworkUnneeded(activeRequest);
+                }
+            }
+        }
+
+        // Third phase : inform the providers that the offer isn't needed for any request
+        // below the active one.
+        for (++i /* skip the active request */; nri.mRequests.size() > i; ++i) {
+            final NetworkRequest request = nri.mRequests.get(i);
+            if (!request.isRequest()) continue; // Listens/track defaults are never sent to offers
+            // Since this request is lower-priority than the one currently satisfied, if the
+            // offer can satisfy it, the provider should not try and bring up the network.
+            // Hence tell the provider so unless it already knew.
+            if (offer.neededFor(request)) {
+                offer.onNetworkUnneeded(request);
+            }
+        }
+    }
+
     private void addNetworkToLegacyTypeTracker(@NonNull final NetworkAgentInfo nai) {
         for (int i = 0; i < nai.numNetworkRequests(); i++) {
             NetworkRequest nr = nai.requestAt(i);
@@ -8405,7 +8376,6 @@ public class ConnectivityService extends IConnectivityManager.Stub
         if (VDBG || DDBG) log("updateNetworkScore for " + nai.toShortString() + " to " + score);
         nai.setScore(score);
         rematchAllNetworksAndRequests();
-        sendUpdatedScoreToFactories(nai);
     }
 
     // Notify only this one new request of the current state. Transfer all the

service/src/com/android/server/connectivity/NetworkAgentInfo.java

@@ -893,6 +893,10 @@ public class NetworkAgentInfo implements Comparable<NetworkAgentInfo> {
         return isWifi && !avoidBadWifi && everValidated;
     }
 
+    public FullScore getScore() {
+        return mScore;
+    }
+
     // Get the current score for this Network.  This may be modified from what the
     // NetworkAgent sent, as it has modifiers applied to it.
     public int getCurrentScore() {

service/src/com/android/server/connectivity/NetworkOffer.java

@@ -17,13 +17,14 @@
 package com.android.server.connectivity;
 
 import android.annotation.NonNull;
-import android.annotation.Nullable;
 import android.net.INetworkOfferCallback;
 import android.net.NetworkCapabilities;
 import android.net.NetworkRequest;
+import android.os.RemoteException;
 
+import java.util.HashSet;
 import java.util.Objects;
-
+import java.util.Set;
 
 /**
  * Represents an offer made by a NetworkProvider to create a network if a need arises.
@@ -44,46 +45,86 @@ public class NetworkOffer {
     @NonNull public final NetworkCapabilities caps;
     @NonNull public final INetworkOfferCallback callback;
     @NonNull public final int providerId;
+    // While this could, in principle, be deduced from the old values of the satisfying networks,
+    // doing so would add a lot of complexity and performance penalties. For each request, the
+    // ranker would have to run again to figure out if this offer used to be able to beat the
+    // previous satisfier to know if there is a change in whether this offer is now needed ;
+    // besides, there would be a need to handle an edge case when a new request comes online,
+    // where it's not satisfied before the first rematch, where starting to satisfy a request
+    // should not result in sending unneeded to this offer. This boolean, while requiring that
+    // the offers are only ever manipulated on the CS thread, is by far a simpler and
+    // economical solution.
+    private final Set<NetworkRequest> mCurrentlyNeeded = new HashSet<>();
 
-    private static NetworkCapabilities emptyCaps() {
-        final NetworkCapabilities nc = new NetworkCapabilities();
-        return nc;
-    }
-
-    // Ideally the caps argument would be non-null, but null has historically meant no filter
-    // and telephony passes null. Keep backward compatibility.
     public NetworkOffer(@NonNull final FullScore score,
-            @Nullable final NetworkCapabilities caps,
+            @NonNull final NetworkCapabilities caps,
             @NonNull final INetworkOfferCallback callback,
             @NonNull final int providerId) {
         this.score = Objects.requireNonNull(score);
-        this.caps = null != caps ? caps : emptyCaps();
+        this.caps = Objects.requireNonNull(caps);
         this.callback = Objects.requireNonNull(callback);
         this.providerId = providerId;
     }
 
+    /**
+     * Tell the provider for this offer that the network is needed for a request.
+     * @param request the request for which the offer is needed
+     */
+    public void onNetworkNeeded(@NonNull final NetworkRequest request) {
+        if (mCurrentlyNeeded.contains(request)) {
+            throw new IllegalStateException("Network already needed");
+        }
+        mCurrentlyNeeded.add(request);
+        try {
+            callback.onNetworkNeeded(request);
+        } catch (final RemoteException e) {
+            // The provider is dead. It will be removed by the death recipient.
+        }
+    }
+
+    /**
+     * Tell the provider for this offer that the network is no longer needed for this request.
+     *
+     * onNetworkNeeded will have been called with the same request before.
+     *
+     * @param request the request
+     */
+    public void onNetworkUnneeded(@NonNull final NetworkRequest request) {
+        if (!mCurrentlyNeeded.contains(request)) {
+            throw new IllegalStateException("Network already unneeded");
+        }
+        mCurrentlyNeeded.remove(request);
+        try {
+            callback.onNetworkUnneeded(request);
+        } catch (final RemoteException e) {
+            // The provider is dead. It will be removed by the death recipient.
+        }
+    }
+
+    /**
+     * Returns whether this offer is currently needed for this request.
+     * @param request the request
+     * @return whether the offer is currently considered needed
+     */
+    public boolean neededFor(@NonNull final NetworkRequest request) {
+        return mCurrentlyNeeded.contains(request);
+    }
+
     /**
      * Migrate from, and take over, a previous offer.
      *
      * When an updated offer is sent from a provider, call this method on the new offer, passing
      * the old one, to take over the state.
      *
-     * @param previousOffer
+     * @param previousOffer the previous offer
      */
     public void migrateFrom(@NonNull final NetworkOffer previousOffer) {
         if (!callback.equals(previousOffer.callback)) {
             throw new IllegalArgumentException("Can only migrate from a previous version of"
                     + " the same offer");
         }
-    }
+        mCurrentlyNeeded.clear();
-
+        mCurrentlyNeeded.addAll(previousOffer.mCurrentlyNeeded);
-    /**
-     * Returns whether an offer can satisfy a NetworkRequest, according to its capabilities.
-     * @param request The request to test against.
-     * @return Whether this offer can satisfy the request.
-     */
-    public final boolean canSatisfy(@NonNull final NetworkRequest request) {
-        return request.networkCapabilities.satisfiedByNetworkCapabilities(caps);
     }
 
     @Override

service/src/com/android/server/connectivity/NetworkRanker.java

@@ -18,6 +18,7 @@ package com.android.server.connectivity;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.net.NetworkCapabilities;
 import android.net.NetworkRequest;
 
 import java.util.Collection;
@@ -47,4 +48,41 @@ public class NetworkRanker {
         }
         return bestNetwork;
     }
+
+    /**
+     * Returns whether an offer has a chance to beat a champion network for a request.
+     *
+     * Offers are sent by network providers when they think they might be able to make a network
+     * with the characteristics contained in the offer. If the offer has no chance to beat
+     * the currently best network for a given request, there is no point in the provider spending
+     * power trying to find and bring up such a network.
+     *
+     * Note that having an offer up does not constitute a commitment from the provider part
+     * to be able to bring up a network with these characteristics, or a network at all for
+     * that matter. This is only used to save power by letting providers know when they can't
+     * beat a current champion.
+     *
+     * @param request The request to evaluate against.
+     * @param championScore The currently best network for this request.
+     * @param offer The offer.
+     * @return Whether the offer stands a chance to beat the champion.
+     */
+    public boolean mightBeat(@NonNull final NetworkRequest request,
+            @Nullable final FullScore championScore,
+            @NonNull final NetworkOffer offer) {
+        // If this network can't even satisfy the request then it can't beat anything, not
+        // even an absence of network. It can't satisfy it anyway.
+        if (!request.canBeSatisfiedBy(offer.caps)) return false;
+        // If there is no satisfying network, then this network can beat, because some network
+        // is always better than no network.
+        if (null == championScore) return true;
+        final int offerIntScore;
+        if (offer.caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)) {
+            // If the offer might have Internet access, then it might validate.
+            offerIntScore = offer.score.getLegacyIntAsValidated();
+        } else {
+            offerIntScore = offer.score.getLegacyInt();
+        }
+        return championScore.getLegacyInt() < offerIntScore;
+    }
 }

tests/common/java/android/net/NetworkProviderTest.kt

@@ -198,4 +198,4 @@ class NetworkProviderTest {
         cb.expectCallback<OnUnavailable>() { nr.getNetworkSpecifier() == specifier }
         mCm.unregisterNetworkProvider(provider)
     }
-}
+}

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

@@ -1029,8 +1029,6 @@ public class ConnectivityServiceTest {
      * operations have been processed and test for them.
      */
     private static class MockNetworkFactory extends NetworkFactory {
-        private final ConditionVariable mNetworkStartedCV = new ConditionVariable();
-        private final ConditionVariable mNetworkStoppedCV = new ConditionVariable();
         private final AtomicBoolean mNetworkStarted = new AtomicBoolean(false);
 
         static class RequestEntry {
@@ -1042,11 +1040,8 @@ public class ConnectivityServiceTest {
             }
 
             static final class Add extends RequestEntry {
-                public final int factorySerialNumber;
+                Add(@NonNull final NetworkRequest request) {
-
-                Add(@NonNull final NetworkRequest request, final int factorySerialNumber) {
                     super(request);
-                    this.factorySerialNumber = factorySerialNumber;
                 }
             }
 
@@ -1055,6 +1050,11 @@ public class ConnectivityServiceTest {
                     super(request);
                 }
             }
+
+            @Override
+            public String toString() {
+                return "RequestEntry [ " + getClass().getName() + " : " + request + " ]";
+            }
         }
 
         // History of received requests adds and removes.
@@ -1066,7 +1066,6 @@ public class ConnectivityServiceTest {
             return obj;
         }
 
-
         public RequestEntry.Add expectRequestAdd() {
             return failIfNull((RequestEntry.Add) mRequestHistory.poll(TIMEOUT_MS,
                     it -> it instanceof RequestEntry.Add), "Expected request add");
@@ -1106,40 +1105,28 @@ public class ConnectivityServiceTest {
 
         protected void startNetwork() {
             mNetworkStarted.set(true);
-            mNetworkStartedCV.open();
         }
 
         protected void stopNetwork() {
             mNetworkStarted.set(false);
-            mNetworkStoppedCV.open();
         }
 
         public boolean getMyStartRequested() {
             return mNetworkStarted.get();
         }
 
-        public ConditionVariable getNetworkStartedCV() {
-            mNetworkStartedCV.close();
-            return mNetworkStartedCV;
-        }
-
-        public ConditionVariable getNetworkStoppedCV() {
-            mNetworkStoppedCV.close();
-            return mNetworkStoppedCV;
-        }
 
         @Override
-        protected void handleAddRequest(NetworkRequest request, int score,
+        protected void needNetworkFor(NetworkRequest request) {
-                int factorySerialNumber) {
             mNetworkRequests.put(request.requestId, request);
-            super.handleAddRequest(request, score, factorySerialNumber);
+            super.needNetworkFor(request);
-            mRequestHistory.add(new RequestEntry.Add(request, factorySerialNumber));
+            mRequestHistory.add(new RequestEntry.Add(request));
         }
 
         @Override
-        protected void handleRemoveRequest(NetworkRequest request) {
+        protected void releaseNetworkFor(NetworkRequest request) {
             mNetworkRequests.remove(request.requestId);
-            super.handleRemoveRequest(request);
+            super.releaseNetworkFor(request);
             mRequestHistory.add(new RequestEntry.Remove(request));
         }
 
@@ -3095,25 +3082,23 @@ public class ConnectivityServiceTest {
         handlerThread.start();
         final MockNetworkFactory testFactory = new MockNetworkFactory(handlerThread.getLooper(),
                 mServiceContext, "testFactory", filter, mCsHandlerThread);
-        testFactory.setScoreFilter(40);
+        testFactory.setScoreFilter(45);
-        ConditionVariable cv = testFactory.getNetworkStartedCV();
         testFactory.register();
-        testFactory.expectRequestAdd();
+
-        testFactory.assertRequestCountEquals(1);
+        final NetworkCallback networkCallback;
-        int expectedRequestCount = 1;
-        NetworkCallback networkCallback = null;
-        // For non-INTERNET capabilities we cannot rely on the default request being present, so
-        // add one.
         if (capability != NET_CAPABILITY_INTERNET) {
+            // If the capability passed in argument is part of the default request, then the
+            // factory will see the default request. Otherwise the filter will prevent the
+            // factory from seeing it. In that case, add a request so it can be tested.
             assertFalse(testFactory.getMyStartRequested());
             NetworkRequest request = new NetworkRequest.Builder().addCapability(capability).build();
             networkCallback = new NetworkCallback();
             mCm.requestNetwork(request, networkCallback);
-            expectedRequestCount++;
+        } else {
-            testFactory.expectRequestAdd();
+            networkCallback = null;
         }
-        waitFor(cv);
+        testFactory.expectRequestAdd();
-        testFactory.assertRequestCountEquals(expectedRequestCount);
+        testFactory.assertRequestCountEquals(1);
         assertTrue(testFactory.getMyStartRequested());
 
         // Now bring in a higher scored network.
@@ -3122,20 +3107,45 @@ public class ConnectivityServiceTest {
         // own NetworkRequest during startup, just bump up the score to cancel out the
         // unvalidated penalty.
         testAgent.adjustScore(40);
-        cv = testFactory.getNetworkStoppedCV();
 
-        // When testAgent connects, ConnectivityService will re-send us all current requests with
+        // When testAgent connects, because of its 50 score (50 for cell + 40 adjustment score
-        // the new score. There are expectedRequestCount such requests, and we must wait for all of
+        // - 40 penalty for not being validated), it will beat the testFactory's offer, so
-        // them.
+        // the request will be removed.
         testAgent.connect(false);
         testAgent.addCapability(capability);
-        waitFor(cv);
+        testFactory.expectRequestRemove();
-        testFactory.expectRequestAdds(expectedRequestCount);
+        testFactory.assertRequestCountEquals(0);
-        testFactory.assertRequestCountEquals(expectedRequestCount);
         assertFalse(testFactory.getMyStartRequested());
 
+        // Add a request and make sure it's not sent to the factory, because the agent
+        // is satisfying it better.
+        final NetworkCallback cb = new ConnectivityManager.NetworkCallback();
+        mCm.requestNetwork(new NetworkRequest.Builder().addCapability(capability).build(), cb);
+        expectNoRequestChanged(testFactory);
+        testFactory.assertRequestCountEquals(0);
+        assertFalse(testFactory.getMyStartRequested());
+
+        // Make the test agent weak enough to have the exact same score as the
+        // factory (50 for cell + 40 adjustment -40 validation penalty - 5 adjustment). Make sure
+        // the factory doesn't see the request.
+        testAgent.adjustScore(-5);
+        expectNoRequestChanged(testFactory);
+        assertFalse(testFactory.getMyStartRequested());
+
+        // Make the test agent weak enough to see the two requests (the one that was just sent,
+        // and either the default one or the one sent at the top of this test if the default
+        // won't be seen).
+        testAgent.adjustScore(-45);
+        testFactory.expectRequestAdds(2);
+        testFactory.assertRequestCountEquals(2);
+        assertTrue(testFactory.getMyStartRequested());
+
+        // Now unregister and make sure the request is removed.
+        mCm.unregisterNetworkCallback(cb);
+        testFactory.expectRequestRemove();
+
         // Bring in a bunch of requests.
-        assertEquals(expectedRequestCount, testFactory.getMyRequestCount());
+        assertEquals(1, testFactory.getMyRequestCount());
         ConnectivityManager.NetworkCallback[] networkCallbacks =
                 new ConnectivityManager.NetworkCallback[10];
         for (int i = 0; i< networkCallbacks.length; i++) {
@@ -3145,24 +3155,28 @@ public class ConnectivityServiceTest {
             mCm.requestNetwork(builder.build(), networkCallbacks[i]);
         }
         testFactory.expectRequestAdds(10);
-        testFactory.assertRequestCountEquals(10 + expectedRequestCount);
+        testFactory.assertRequestCountEquals(11); // +1 for the default/test specific request
-        assertFalse(testFactory.getMyStartRequested());
+        assertTrue(testFactory.getMyStartRequested());
 
         // Remove the requests.
         for (int i = 0; i < networkCallbacks.length; i++) {
             mCm.unregisterNetworkCallback(networkCallbacks[i]);
         }
         testFactory.expectRequestRemoves(10);
-        testFactory.assertRequestCountEquals(expectedRequestCount);
+        testFactory.assertRequestCountEquals(1);
+        assertTrue(testFactory.getMyStartRequested());
+
+        // Adjust the agent score up again. Expect the request to be withdrawn.
+        testAgent.adjustScore(50);
+        testFactory.expectRequestRemove();
+        testFactory.assertRequestCountEquals(0);
         assertFalse(testFactory.getMyStartRequested());
 
         // Drop the higher scored network.
-        cv = testFactory.getNetworkStartedCV();
         testAgent.disconnect();
-        waitFor(cv);
+        testFactory.expectRequestAdd();
-        testFactory.expectRequestAdds(expectedRequestCount);
+        testFactory.assertRequestCountEquals(1);
-        testFactory.assertRequestCountEquals(expectedRequestCount);
+        assertEquals(1, testFactory.getMyRequestCount());
-        assertEquals(expectedRequestCount, testFactory.getMyRequestCount());
         assertTrue(testFactory.getMyStartRequested());
 
         testFactory.terminate();
@@ -3194,9 +3208,34 @@ public class ConnectivityServiceTest {
     }
 
     @Test
-    public void testNetworkFactoryUnregister() throws Exception {
+    public void testRegisterIgnoringScore() throws Exception {
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.adjustScore(30); // score = 60 (wifi) + 30 = 90
+        mWiFiNetworkAgent.connect(true /* validated */);
+
+        // Make sure the factory sees the default network
         final NetworkCapabilities filter = new NetworkCapabilities();
-        filter.clearAll();
+        filter.addCapability(NET_CAPABILITY_INTERNET);
+        filter.addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
+        final HandlerThread handlerThread = new HandlerThread("testNetworkFactoryRequests");
+        handlerThread.start();
+        final MockNetworkFactory testFactory = new MockNetworkFactory(handlerThread.getLooper(),
+                mServiceContext, "testFactory", filter, mCsHandlerThread);
+        testFactory.registerIgnoringScore();
+        testFactory.expectRequestAdd();
+
+        mWiFiNetworkAgent.adjustScore(20); // exceed the maximum score
+        expectNoRequestChanged(testFactory); // still seeing the request
+
+        mWiFiNetworkAgent.disconnect();
+    }
+
+    @Test
+    public void testNetworkFactoryUnregister() throws Exception {
+        // Make sure the factory sees the default network
+        final NetworkCapabilities filter = new NetworkCapabilities();
+        filter.addCapability(NET_CAPABILITY_INTERNET);
+        filter.addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
 
         final HandlerThread handlerThread = new HandlerThread("testNetworkFactoryRequests");
         handlerThread.start();
@@ -4455,6 +4494,7 @@ public class ConnectivityServiceTest {
         testFactory.register();
 
         try {
+            // Expect the factory to receive the default network request.
             testFactory.expectRequestAdd();
             testFactory.assertRequestCountEquals(1);
             assertTrue(testFactory.getMyStartRequested());
@@ -4463,25 +4503,44 @@ public class ConnectivityServiceTest {
             mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
             // Score 60 - 40 penalty for not validated yet, then 60 when it validates
             mWiFiNetworkAgent.connect(true);
-            // Default request and mobile always on request
+            // The network connects with a low score, so the offer can still beat it and
-            testFactory.expectRequestAdds(2);
+            // nothing happens. Then the network validates, and the offer with its filter score
+            // of 40 can no longer beat it and the request is removed.
+            testFactory.expectRequestRemove();
+            testFactory.assertRequestCountEquals(0);
+
             assertFalse(testFactory.getMyStartRequested());
 
-            // Turn on mobile data always on. The factory starts looking again.
+            // Turn on mobile data always on. This request will not match the wifi request, so
+            // it will be sent to the test factory whose filters allow to see it.
             setAlwaysOnNetworks(true);
             testFactory.expectRequestAdd();
-            testFactory.assertRequestCountEquals(2);
+            testFactory.assertRequestCountEquals(1);
 
             assertTrue(testFactory.getMyStartRequested());
 
             // Bring up cell data and check that the factory stops looking.
             assertLength(1, mCm.getAllNetworks());
             mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
-            mCellNetworkAgent.connect(true);
+            mCellNetworkAgent.connect(false);
-            cellNetworkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+            cellNetworkCallback.expectAvailableCallbacks(mCellNetworkAgent, false, false, false,
-            testFactory.expectRequestAdds(2); // Unvalidated and validated
+                    TEST_CALLBACK_TIMEOUT_MS);
-            testFactory.assertRequestCountEquals(2);
+            // When cell connects, it will satisfy the "mobile always on request" right away
-            // The cell network outscores the factory filter, so start is not requested.
+            // by virtue of being the only network that can satisfy the request. However, its
+            // score is low (50 - 40 = 10) so the test factory can still hope to beat it.
+            expectNoRequestChanged(testFactory);
+
+            // Next, cell validates. This gives it a score of 50 and the test factory can't
+            // hope to beat that according to its filters. It will see the message that its
+            // offer is now unnecessary.
+            mCellNetworkAgent.setNetworkValid(true);
+            // Need a trigger point to let NetworkMonitor tell ConnectivityService that network is
+            // validated – see testPartialConnectivity.
+            mCm.reportNetworkConnectivity(mCellNetworkAgent.getNetwork(), true);
+            cellNetworkCallback.expectCapabilitiesWith(NET_CAPABILITY_VALIDATED, mCellNetworkAgent);
+            testFactory.expectRequestRemove();
+            testFactory.assertRequestCountEquals(0);
+            // Accordingly, the factory shouldn't be started.
             assertFalse(testFactory.getMyStartRequested());
 
             // Check that cell data stays up.
@@ -4489,10 +4548,27 @@ public class ConnectivityServiceTest {
             verifyActiveNetwork(TRANSPORT_WIFI);
             assertLength(2, mCm.getAllNetworks());
 
-            // Turn off mobile data always on and expect the request to disappear...
+            // Cell disconnects. There is still the "mobile data always on" request outstanding,
-            setAlwaysOnNetworks(false);
+            // and the test factory should see it now that it isn't hopelessly outscored.
-            testFactory.expectRequestRemove();
+            mCellNetworkAgent.disconnect();
+            cellNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
+            assertLength(1, mCm.getAllNetworks());
+            testFactory.expectRequestAdd();
+            testFactory.assertRequestCountEquals(1);
 
+            // Reconnect cell validated, see the request disappear again. Then withdraw the
+            // mobile always on request. This will tear down cell, and there shouldn't be a
+            // blip where the test factory briefly sees the request or anything.
+            mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+            mCellNetworkAgent.connect(true);
+            cellNetworkCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+            assertLength(2, mCm.getAllNetworks());
+            testFactory.expectRequestRemove();
+            testFactory.assertRequestCountEquals(0);
+            setAlwaysOnNetworks(false);
+            expectNoRequestChanged(testFactory);
+            testFactory.assertRequestCountEquals(0);
+            assertFalse(testFactory.getMyStartRequested());
             // ...  and cell data to be torn down after nascent network timeout.
             cellNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent,
                     mService.mNascentDelayMs + TEST_CALLBACK_TIMEOUT_MS);
@@ -4795,7 +4871,8 @@ public class ConnectivityServiceTest {
         handlerThread.start();
         NetworkCapabilities filter = new NetworkCapabilities()
                 .addTransportType(TRANSPORT_WIFI)
-                .addCapability(NET_CAPABILITY_INTERNET);
+                .addCapability(NET_CAPABILITY_INTERNET)
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
         final MockNetworkFactory testFactory = new MockNetworkFactory(handlerThread.getLooper(),
                 mServiceContext, "testFactory", filter, mCsHandlerThread);
         testFactory.setScoreFilter(40);
@@ -4804,32 +4881,43 @@ public class ConnectivityServiceTest {
         testFactory.register();
         testFactory.expectRequestAdd();
 
-        // Now file the test request and expect it.
+        try {
-        mCm.requestNetwork(nr, networkCallback);
+            // Now file the test request and expect it.
-        final NetworkRequest newRequest = testFactory.expectRequestAdd().request;
+            mCm.requestNetwork(nr, networkCallback);
+            final NetworkRequest newRequest = testFactory.expectRequestAdd().request;
 
-        if (preUnregister) {
+            if (preUnregister) {
-            mCm.unregisterNetworkCallback(networkCallback);
+                mCm.unregisterNetworkCallback(networkCallback);
 
-            // Simulate the factory releasing the request as unfulfillable: no-op since
+                // The request has been released : the factory should see it removed
-            // the callback has already been unregistered (but a test that no exceptions are
+                // immediately.
-            // thrown).
+                testFactory.expectRequestRemove();
-            testFactory.triggerUnfulfillable(newRequest);
-        } else {
-            // Simulate the factory releasing the request as unfulfillable and expect onUnavailable!
-            testFactory.triggerUnfulfillable(newRequest);
 
-            networkCallback.expectCallback(CallbackEntry.UNAVAILABLE, (Network) null);
+                // Simulate the factory releasing the request as unfulfillable: no-op since
+                // the callback has already been unregistered (but a test that no exceptions are
+                // thrown).
+                testFactory.triggerUnfulfillable(newRequest);
+            } else {
+                // Simulate the factory releasing the request as unfulfillable and expect
+                // onUnavailable!
+                testFactory.triggerUnfulfillable(newRequest);
 
-            // unregister network callback - a no-op (since already freed by the
+                networkCallback.expectCallback(CallbackEntry.UNAVAILABLE, (Network) null);
-            // on-unavailable), but should not fail or throw exceptions.
+
-            mCm.unregisterNetworkCallback(networkCallback);
+                // Declaring a request unfulfillable releases it automatically.
+                testFactory.expectRequestRemove();
+
+                // unregister network callback - a no-op (since already freed by the
+                // on-unavailable), but should not fail or throw exceptions.
+                mCm.unregisterNetworkCallback(networkCallback);
+
+                // The factory should not see any further removal, as this request has
+                // already been removed.
+            }
+        } finally {
+            testFactory.terminate();
+            handlerThread.quit();
         }
-
-        testFactory.expectRequestRemove();
-
-        testFactory.terminate();
-        handlerThread.quit();
     }
 
     private static class TestKeepaliveCallback extends PacketKeepaliveCallback {
@@ -11588,6 +11676,115 @@ public class ConnectivityServiceTest {
         // default callbacks will be unregistered in tearDown
     }
 
+    @Test
+    public void testNetworkFactoryRequestsWithMultilayerRequest()
+            throws Exception {
+        // First use OEM_PAID preference to create a multi-layer request : 1. listen for
+        // unmetered, 2. request network with cap OEM_PAID, 3, request the default network for
+        // fallback.
+        @OemNetworkPreferences.OemNetworkPreference final int networkPref =
+                OemNetworkPreferences.OEM_NETWORK_PREFERENCE_OEM_PAID;
+        setupMultipleDefaultNetworksForOemNetworkPreferenceCurrentUidTest(networkPref);
+
+        final HandlerThread handlerThread = new HandlerThread("MockFactory");
+        handlerThread.start();
+        NetworkCapabilities internetFilter = new NetworkCapabilities()
+                .addCapability(NET_CAPABILITY_INTERNET)
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED);
+        final MockNetworkFactory internetFactory = new MockNetworkFactory(handlerThread.getLooper(),
+                mServiceContext, "internetFactory", internetFilter, mCsHandlerThread);
+        internetFactory.setScoreFilter(40);
+        internetFactory.register();
+        // Default internet request & 3rd (fallback) request in OEM_PAID NRI. The unmetered request
+        // is never sent to factories (it's a LISTEN, not requestable) and the OEM_PAID request
+        // doesn't match the internetFactory filter.
+        internetFactory.expectRequestAdds(2);
+
+        NetworkCapabilities oemPaidFilter = new NetworkCapabilities()
+                .addCapability(NET_CAPABILITY_INTERNET)
+                .addCapability(NET_CAPABILITY_OEM_PAID)
+                .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
+                .removeCapability(NET_CAPABILITY_NOT_RESTRICTED);
+        final MockNetworkFactory oemPaidFactory = new MockNetworkFactory(handlerThread.getLooper(),
+                mServiceContext, "oemPaidFactory", oemPaidFilter, mCsHandlerThread);
+        oemPaidFactory.setScoreFilter(40);
+        oemPaidFactory.register();
+        oemPaidFactory.expectRequestAdd(); // Because nobody satisfies the request
+
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+        mCellNetworkAgent.connect(true);
+
+        // A network connected that satisfies the default internet request. For the OEM_PAID
+        // preference, this is not as good as an OEM_PAID network, so even if the score of
+        // the network is better than the factory announced, it still should try to bring up
+        // the network.
+        expectNoRequestChanged(oemPaidFactory);
+        oemPaidFactory.assertRequestCountEquals(1);
+        // The internet factory however is outscored, and should lose its requests.
+        internetFactory.expectRequestRemoves(2);
+        internetFactory.assertRequestCountEquals(0);
+
+        final NetworkCapabilities oemPaidNc = new NetworkCapabilities();
+        oemPaidNc.addCapability(NET_CAPABILITY_OEM_PAID);
+        oemPaidNc.removeCapability(NET_CAPABILITY_NOT_RESTRICTED);
+        final TestNetworkAgentWrapper oemPaidAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR,
+                new LinkProperties(), oemPaidNc);
+        oemPaidAgent.connect(true);
+
+        // The oemPaidAgent has score 50 (default for cell) so it beats what the oemPaidFactory can
+        // provide, therefore it loses the request.
+        oemPaidFactory.expectRequestRemove();
+        oemPaidFactory.assertRequestCountEquals(0);
+        expectNoRequestChanged(internetFactory);
+        internetFactory.assertRequestCountEquals(0);
+
+        oemPaidAgent.adjustScore(-30);
+        // Now the that the agent is weak, the oemPaidFactory can beat the existing network for the
+        // OEM_PAID request. The internet factory however can't beat a network that has OEM_PAID
+        // for the preference request, so it doesn't see the request.
+        oemPaidFactory.expectRequestAdd();
+        oemPaidFactory.assertRequestCountEquals(1);
+        expectNoRequestChanged(internetFactory);
+        internetFactory.assertRequestCountEquals(0);
+
+        mCellNetworkAgent.disconnect();
+        // The network satisfying the default internet request has disconnected, so the
+        // internetFactory sees the default request again. However there is a network with OEM_PAID
+        // connected, so the 2nd OEM_PAID req is already satisfied, so the oemPaidFactory doesn't
+        // care about networks that don't have OEM_PAID.
+        expectNoRequestChanged(oemPaidFactory);
+        oemPaidFactory.assertRequestCountEquals(1);
+        internetFactory.expectRequestAdd();
+        internetFactory.assertRequestCountEquals(1);
+
+        // Cell connects again, still with score 50. Back to the previous state.
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+        mCellNetworkAgent.connect(true);
+        expectNoRequestChanged(oemPaidFactory);
+        oemPaidFactory.assertRequestCountEquals(1);
+        internetFactory.expectRequestRemove();
+        internetFactory.assertRequestCountEquals(0);
+
+        // Now WiFi connects and it's unmetered, but it's weaker than cell.
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.addCapability(NET_CAPABILITY_NOT_METERED);
+        mWiFiNetworkAgent.adjustScore(-30); // Not the best Internet network, but unmetered
+        mWiFiNetworkAgent.connect(true);
+
+        // The OEM_PAID preference prefers an unmetered network to an OEM_PAID network, so
+        // the oemPaidFactory can't beat this no matter how high its score.
+        oemPaidFactory.expectRequestRemove();
+        expectNoRequestChanged(internetFactory);
+
+        mCellNetworkAgent.disconnect();
+        // Now that the best internet network (cell, with its 50 score compared to 30 for WiFi
+        // at this point), the default internet request is satisfied by a network worse than
+        // the internetFactory announced, so it gets the request. However, there is still an
+        // unmetered network, so the oemPaidNetworkFactory still can't beat this.
+        expectNoRequestChanged(oemPaidFactory);
+        internetFactory.expectRequestAdd();
+    }
+
     /**
      * Test network priority for OEM_NETWORK_PREFERENCE_OEM_PAID_NO_FALLBACK in the following order:
      * NET_CAPABILITY_NOT_METERED -> NET_CAPABILITY_OEM_PAID
@@ -11909,11 +12106,11 @@ public class ConnectivityServiceTest {
         testFactory.setScoreFilter(40);
 
         try {
-            // Register the factory and expect it will see default request, because all requests
+            // Register the factory. It doesn't see the default request because its filter does
-            // are sent to all factories.
+            // not include INTERNET.
             testFactory.register();
-            testFactory.expectRequestAdd();
+            expectNoRequestChanged(testFactory);
-            testFactory.assertRequestCountEquals(1);
+            testFactory.assertRequestCountEquals(0);
             // The factory won't try to start the network since the default request doesn't
             // match the filter (no INTERNET capability).
             assertFalse(testFactory.getMyStartRequested());
@@ -11926,7 +12123,7 @@ public class ConnectivityServiceTest {
                     bestMatchingCb, mCsHandlerThread.getThreadHandler());
             bestMatchingCb.assertNoCallback();
             expectNoRequestChanged(testFactory);
-            testFactory.assertRequestCountEquals(1);
+            testFactory.assertRequestCountEquals(0);
             assertFalse(testFactory.getMyStartRequested());
 
             // Fire a normal mms request, verify the factory will only see the request.
@@ -11935,13 +12132,13 @@ public class ConnectivityServiceTest {
                     .addCapability(NET_CAPABILITY_MMS).build();
             mCm.requestNetwork(mmsRequest, mmsNetworkCallback);
             testFactory.expectRequestAdd();
-            testFactory.assertRequestCountEquals(2);
+            testFactory.assertRequestCountEquals(1);
             assertTrue(testFactory.getMyStartRequested());
 
             // Unregister best matching callback, verify factory see no change.
             mCm.unregisterNetworkCallback(bestMatchingCb);
             expectNoRequestChanged(testFactory);
-            testFactory.assertRequestCountEquals(2);
+            testFactory.assertRequestCountEquals(1);
             assertTrue(testFactory.getMyStartRequested());
         } finally {
             testFactory.terminate();

tests/unit/java/com/android/server/connectivity/NetworkOfferTest.kt

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.connectivity
+
+import android.net.INetworkOfferCallback
+import android.net.NetworkCapabilities
+import android.net.NetworkRequest
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentMatchers.eq
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.verify
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+const val POLICY_NONE = 0L
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class NetworkOfferTest {
+    val mockCallback = mock(INetworkOfferCallback::class.java)
+
+    @Test
+    fun testOfferNeededUnneeded() {
+        val score = FullScore(50, POLICY_NONE)
+        val offer = NetworkOffer(score, NetworkCapabilities.Builder().build(), mockCallback,
+                1 /* providerId */)
+        val request1 = mock(NetworkRequest::class.java)
+        val request2 = mock(NetworkRequest::class.java)
+        offer.onNetworkNeeded(request1)
+        verify(mockCallback).onNetworkNeeded(eq(request1))
+        assertTrue(offer.neededFor(request1))
+        assertFalse(offer.neededFor(request2))
+
+        offer.onNetworkNeeded(request2)
+        verify(mockCallback).onNetworkNeeded(eq(request2))
+        assertTrue(offer.neededFor(request1))
+        assertTrue(offer.neededFor(request2))
+
+        // Note that the framework never calls onNetworkNeeded multiple times with the same
+        // request without calling onNetworkUnneeded first. It would be incorrect usage and the
+        // behavior would be undefined, so there is nothing to test.
+
+        offer.onNetworkUnneeded(request1)
+        verify(mockCallback).onNetworkUnneeded(eq(request1))
+        assertFalse(offer.neededFor(request1))
+        assertTrue(offer.neededFor(request2))
+
+        offer.onNetworkUnneeded(request2)
+        verify(mockCallback).onNetworkUnneeded(eq(request2))
+        assertFalse(offer.neededFor(request1))
+        assertFalse(offer.neededFor(request2))
+    }
+}