Merge "[SM09] Add helper class to monitor RAT type change per sub" am: 64ccb889

/*

 * 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.getActiveAndHiddenSubscriptionIdList();

        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);

        }

    }

}