Merge "[SM09] Add helper class to monitor RAT type change per sub" into rvc-dev

1 files changed, 211 insertions, 0 deletions

diff --git a/services/core/java/com/android/server/net/NetworkStatsSubscriptionsMonitor.java b/services/core/java/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
new file mode 100644
index 000000000000..0bdf3f22ee9a
--- /dev/null
+++ b/services/core/java/com/android/server/net/NetworkStatsSubscriptionsMonitor.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2020 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.net;
+
+import static android.net.NetworkTemplate.getCollapsedRatType;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.telephony.Annotation;
+import android.telephony.PhoneStateListener;
+import android.telephony.ServiceState;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
+import android.text.TextUtils;
+import android.util.Log;
+
+import com.android.internal.util.CollectionUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.Executor;
+
+/**
+ * Helper class that watches for events that are triggered per subscription.
+ */
+// TODO (b/152176562): Write tests to verify subscription changes generate corresponding
+//  register/unregister calls.
+public class NetworkStatsSubscriptionsMonitor extends
+        SubscriptionManager.OnSubscriptionsChangedListener {
+
+    /**
+     * Interface that this monitor uses to delegate event handling to NetworkStatsService.
+     */
+    public interface Delegate {
+        /**
+         * Notify that the collapsed RAT type has been changed for any subscription. The method
+         * will also be triggered for any existing sub when start and stop monitoring.
+         *
+         * @param subscriberId IMSI of the subscription.
+         * @param collapsedRatType collapsed RAT type.
+         *                         @see android.net.NetworkTemplate#getCollapsedRatType(int).
+         */
+        void onCollapsedRatTypeChanged(@NonNull String subscriberId,
+                @Annotation.NetworkType int collapsedRatType);
+    }
+    private final Delegate mDelegate;
+
+    /**
+     * Receivers that watches for {@link ServiceState} changes for each subscription, to
+     * monitor the transitioning between Radio Access Technology(RAT) types for each sub.
+     */
+    @NonNull
+    private final CopyOnWriteArrayList<RatTypeListener> mRatListeners =
+            new CopyOnWriteArrayList<>();
+
+    @NonNull
+    private final SubscriptionManager mSubscriptionManager;
+    @NonNull
+    private final TelephonyManager mTeleManager;
+
+    @NonNull
+    private final Executor mExecutor;
+
+    NetworkStatsSubscriptionsMonitor(@NonNull Context context, @NonNull Executor executor,
+            @NonNull Delegate delegate) {
+        super();
+        mSubscriptionManager = (SubscriptionManager) context.getSystemService(
+                Context.TELEPHONY_SUBSCRIPTION_SERVICE);
+        mTeleManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
+        mExecutor = executor;
+        mDelegate = delegate;
+    }
+
+    @Override
+    public void onSubscriptionsChanged() {
+        // Collect active subId list, hidden subId such as opportunistic subscriptions are
+        // also needed to track CBRS.
+        final List<Integer> newSubs = getActiveSubIdList(mSubscriptionManager);
+
+        for (final int subId : newSubs) {
+            final RatTypeListener match = CollectionUtils.find(mRatListeners,
+                    it -> it.mSubId == subId);
+            if (match != null) continue;
+
+            // Create listener for every newly added sub. Also store subscriberId into it to
+            // prevent binder call to telephony when querying RAT.
+            final String subscriberId = mTeleManager.getSubscriberId(subId);
+            if (TextUtils.isEmpty(subscriberId)) {
+                Log.wtf(NetworkStatsService.TAG,
+                        "Empty subscriberId for newly added sub: " + subId);
+            }
+            final RatTypeListener listener =
+                    new RatTypeListener(mExecutor, this, subId, subscriberId);
+            mRatListeners.add(listener);
+
+            // Register listener to the telephony manager that associated with specific sub.
+            mTeleManager.createForSubscriptionId(subId)
+                    .listen(listener, PhoneStateListener.LISTEN_SERVICE_STATE);
+        }
+
+        for (final RatTypeListener listener : new ArrayList<>(mRatListeners)) {
+            // If the new list contains the subId of the listener, keeps it.
+            final Integer match = CollectionUtils.find(newSubs, it -> it == listener.mSubId);
+            if (match != null) continue;
+
+            handleRemoveRatTypeListener(listener);
+        }
+    }
+
+    @NonNull
+    private List<Integer> getActiveSubIdList(@NonNull SubscriptionManager subscriptionManager) {
+        final ArrayList<Integer> ret = new ArrayList<>();
+        final int[] ids = subscriptionManager.getCompleteActiveSubscriptionIdList();
+        for (int id : ids) ret.add(id);
+        return ret;
+    }
+
+    /**
+     * Get a collapsed RatType for the given subscriberId.
+     *
+     * @param subscriberId the target subscriberId
+     * @return collapsed RatType for the given subscriberId
+     */
+    public int getRatTypeForSubscriberId(@NonNull String subscriberId) {
+        final RatTypeListener match = CollectionUtils.find(mRatListeners,
+                it -> TextUtils.equals(subscriberId, it.mSubscriberId));
+        return match != null ? match.mLastCollapsedRatType : TelephonyManager.NETWORK_TYPE_UNKNOWN;
+    }
+
+    /**
+     * Start monitoring events that triggered per subscription.
+     */
+    public void start() {
+        mSubscriptionManager.addOnSubscriptionsChangedListener(mExecutor, this);
+    }
+
+    /**
+     * Unregister subscription changes and all listeners for each subscription.
+     */
+    public void stop() {
+        mSubscriptionManager.removeOnSubscriptionsChangedListener(this);
+
+        for (final RatTypeListener listener : new ArrayList<>(mRatListeners)) {
+            handleRemoveRatTypeListener(listener);
+        }
+    }
+
+    private void handleRemoveRatTypeListener(@NonNull RatTypeListener listener) {
+        mTeleManager.createForSubscriptionId(listener.mSubId)
+                .listen(listener, PhoneStateListener.LISTEN_NONE);
+        mRatListeners.remove(listener);
+
+        // Removal of subscriptions doesn't generate RAT changed event, fire it for every
+        // RatTypeListener.
+        mDelegate.onCollapsedRatTypeChanged(
+                listener.mSubscriberId, TelephonyManager.NETWORK_TYPE_UNKNOWN);
+    }
+
+    static class RatTypeListener extends PhoneStateListener {
+        // Unique id for the subscription. See {@link SubscriptionInfo#getSubscriptionId}.
+        @NonNull
+        private final int mSubId;
+
+        // IMSI to identifying the corresponding network from {@link NetworkState}.
+        // See {@link TelephonyManager#getSubscriberId}.
+        @NonNull
+        private final String mSubscriberId;
+
+        private volatile int mLastCollapsedRatType = TelephonyManager.NETWORK_TYPE_UNKNOWN;
+        @NonNull
+        private final NetworkStatsSubscriptionsMonitor mMonitor;
+
+        RatTypeListener(@NonNull Executor executor,
+                @NonNull NetworkStatsSubscriptionsMonitor monitor, int subId,
+                @NonNull String subscriberId) {
+            super(executor);
+            mSubId = subId;
+            mSubscriberId = subscriberId;
+            mMonitor = monitor;
+        }
+
+        @Override
+        public void onServiceStateChanged(@NonNull ServiceState ss) {
+            final int networkType = ss.getDataNetworkType();
+            final int collapsedRatType = getCollapsedRatType(networkType);
+            if (collapsedRatType == mLastCollapsedRatType) return;
+
+            if (NetworkStatsService.LOGD) {
+                Log.d(NetworkStatsService.TAG, "subtype changed for sub(" + mSubId + "): "
+                        + mLastCollapsedRatType + " -> " + collapsedRatType);
+            }
+            mLastCollapsedRatType = collapsedRatType;
+            mMonitor.mDelegate.onCollapsedRatTypeChanged(mSubscriberId, mLastCollapsedRatType);
+        }
+    }
+}