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Commit aac396d6 authored by Nathan Harold's avatar Nathan Harold
Browse files

Fix NPE in LinkBandwidthEstimator 

Rearrange the null check protections and make
a number of small safety and readability improvements
to reduce the changes of another bug like this.

Bug: 270831206
Test: atest LinkBandwidthEstimatorTest #regression-test

Merged-In: Ib4f37db0cd5a5ca83e8fea10a8e76d902d1065d4
Change-Id: Ib4f37db0cd5a5ca83e8fea10a8e76d902d1065d4
parent df088874

src/java/com/android/internal/telephony/data/LinkBandwidthEstimator.java

+36 −24
Original line number Original line Diff line number Diff line
@@ -41,12 +41,14 @@ import android.telephony.CellIdentityLte; 
import android.telephony.CellIdentityNr;

import android.telephony.CellIdentityNr;

import android.telephony.CellIdentityTdscdma;

import android.telephony.CellIdentityTdscdma;

import android.telephony.CellIdentityWcdma;

import android.telephony.CellIdentityWcdma;

import android.telephony.CellInfo;

import android.telephony.ModemActivityInfo;

import android.telephony.ModemActivityInfo;

import android.telephony.NetworkRegistrationInfo;

import android.telephony.NetworkRegistrationInfo;

import android.telephony.ServiceState;

import android.telephony.ServiceState;

import android.telephony.SignalStrength;

import android.telephony.SignalStrength;

import android.telephony.TelephonyCallback;

import android.telephony.TelephonyCallback;

import android.telephony.TelephonyManager;

import android.telephony.TelephonyManager;

import android.text.TextUtils;

import android.util.ArrayMap;

import android.util.ArrayMap;

import android.util.ArraySet;

import android.util.ArraySet;

import android.util.LocalLog;

import android.util.LocalLog;
@@ -95,6 +97,9 @@ public class LinkBandwidthEstimator extends Handler { 
    @VisibleForTesting

    @VisibleForTesting

    static final int MSG_DATA_REG_STATE_OR_RAT_CHANGED = 9;

    static final int MSG_DATA_REG_STATE_OR_RAT_CHANGED = 9;





    @VisibleForTesting

    static final int UNKNOWN_TAC = CellInfo.UNAVAILABLE;



    // TODO: move the following parameters to xml file

    // TODO: move the following parameters to xml file

    private static final int TRAFFIC_STATS_POLL_INTERVAL_MS = 1_000;

    private static final int TRAFFIC_STATS_POLL_INTERVAL_MS = 1_000;

    private static final int MODEM_POLL_MIN_INTERVAL_MS = 5_000;

    private static final int MODEM_POLL_MIN_INTERVAL_MS = 5_000;
@@ -178,7 +183,7 @@ public class LinkBandwidthEstimator extends Handler { 
    private int mSignalLevel;

    private int mSignalLevel;

    private int mDataRat = TelephonyManager.NETWORK_TYPE_UNKNOWN;

    private int mDataRat = TelephonyManager.NETWORK_TYPE_UNKNOWN;

    private int mTac;

    private int mTac;

    private String mPlmn = UNKNOWN_PLMN;

    @NonNull private String mPlmn = UNKNOWN_PLMN;

    private NetworkCapabilities mNetworkCapabilities;

    private NetworkCapabilities mNetworkCapabilities;

    private NetworkBandwidth mPlaceholderNetwork;

    private NetworkBandwidth mPlaceholderNetwork;

    private long mFilterUpdateTimeMs;

    private long mFilterUpdateTimeMs;
@@ -1029,22 +1034,28 @@ public class LinkBandwidthEstimator extends Handler { 
    }

    }





    private boolean updateDataRatCellIdentityBandwidth() {

    private boolean updateDataRatCellIdentityBandwidth() {

        boolean updatedPlmn = false;

        final ServiceState ss = mPhone.getServiceState();

        CellIdentity cellIdentity = mPhone.getCurrentCellIdentity();

        final CellIdentity cellIdentity = mPhone.getCurrentCellIdentity();

        mTac = getTac(cellIdentity);



        boolean hasChanged = false;

        String plmn;

        String plmn;





        if (mPhone.getServiceState().getOperatorNumeric() != null) {

        // Why does updating the TAC not result in hasChanged == true?

            plmn = mPhone.getServiceState().getOperatorNumeric();

        // Legacy behavior is currently being preserved for now, but it might very

        } else {

        // well be incorrect. The TAC is part of the network key. This is very fishy.

            if (cellIdentity.getPlmn() != null) {

        mTac = getTac(cellIdentity);



        /* ss should always be non-null */

        if (!TextUtils.isEmpty(ss.getOperatorNumeric())) {

            plmn = ss.getOperatorNumeric();

        } else if (cellIdentity != null && !TextUtils.isEmpty(cellIdentity.getPlmn())) {

            plmn = cellIdentity.getPlmn();

            plmn = cellIdentity.getPlmn();

        } else {

        } else {

            plmn = UNKNOWN_PLMN;

            plmn = UNKNOWN_PLMN;

        }

        }

        }



        if (mPlmn == null || !plmn.equals(mPlmn)) {

        if (!mPlmn.equals(plmn)) {

            updatedPlmn = true;

            hasChanged = true;

            mPlmn = plmn;

            mPlmn = plmn;

        }

        }
@@ -1053,20 +1064,19 @@ public class LinkBandwidthEstimator extends Handler { 
        if (nri != null) {

        if (nri != null) {

            int dataRat = nri.getAccessNetworkTechnology();

            int dataRat = nri.getAccessNetworkTechnology();

            if (dataRat != mDataRat) {

            if (dataRat != mDataRat) {

                updatedRat = true;

                hasChanged = true;

                mDataRat = dataRat;

                mDataRat = dataRat;

                updateStaticBwValue(mDataRat);

                updateStaticBwValue(mDataRat);

                updateByteCountThr();

                updateByteCountThr();

            }

            }

        }

        }





        boolean updatedPlmnOrRat = updatedPlmn || updatedRat;

        if (hasChanged) {

        if (updatedPlmnOrRat) {

            resetBandwidthFilter();

            resetBandwidthFilter();

            updateTxRxBandwidthFilterSendToDataConnection();

            updateTxRxBandwidthFilterSendToDataConnection();

            mLastPlmnOrRatChangeTimeMs = mTelephonyFacade.getElapsedSinceBootMillis();

            mLastPlmnOrRatChangeTimeMs = mTelephonyFacade.getElapsedSinceBootMillis();

        }

        }

        return updatedPlmnOrRat;

        return hasChanged;

    }

    }





    private int getTac(@NonNull CellIdentity cellIdentity) {

    private int getTac(@NonNull CellIdentity cellIdentity) {
@@ -1085,7 +1095,7 @@ public class LinkBandwidthEstimator extends Handler { 
        if (cellIdentity instanceof CellIdentityGsm) {

        if (cellIdentity instanceof CellIdentityGsm) {

            return ((CellIdentityGsm) cellIdentity).getLac();

            return ((CellIdentityGsm) cellIdentity).getLac();

        }

        }

        return 0;

        return UNKNOWN_TAC;

    }

    }





    private class TelephonyCallbackImpl extends TelephonyCallback implements

    private class TelephonyCallbackImpl extends TelephonyCallback implements
@@ -1110,16 +1120,17 @@ public class LinkBandwidthEstimator extends Handler { 
        mLocalLog.log(msg);

        mLocalLog.log(msg);

    }

    }





    @VisibleForTesting

    static final int UNKNOWN_TAC = -1;

    // Map with NetworkKey as the key and NetworkBandwidth as the value.

    // Map with NetworkKey as the key and NetworkBandwidth as the value.

    // NetworkKey is specified by the PLMN, data RAT and TAC of network.

    // NetworkKey is specified by the PLMN, data RAT and TAC of network.

    // NetworkBandwidth represents the bandwidth related stats of each network.

    // NetworkBandwidth represents the bandwidth related stats of each network.

    private final Map<NetworkKey, NetworkBandwidth> mNetworkMap = new ArrayMap<>();

    private final Map<NetworkKey, NetworkBandwidth> mNetworkMap = new ArrayMap<>();



    private static class NetworkKey {

    private static class NetworkKey {



        private final String mPlmn;

        private final String mPlmn;

        private final String mDataRat;

        private final String mDataRat;

        private final int mTac;

        private final int mTac;



        NetworkKey(String plmn, int tac, String dataRat) {

        NetworkKey(String plmn, int tac, String dataRat) {

            mPlmn = plmn;

            mPlmn = plmn;

            mTac = tac;

            mTac = tac;
@@ -1156,15 +1167,15 @@ public class LinkBandwidthEstimator extends Handler { 
    }

    }





    @NonNull

    @NonNull

    private NetworkBandwidth lookupNetwork(String plmn, String dataRat) {

    private NetworkBandwidth lookupNetwork(@NonNull String plmn, String dataRat) {

        return lookupNetwork(plmn, UNKNOWN_TAC, dataRat);

        return lookupNetwork(plmn, UNKNOWN_TAC, dataRat);

    }

    }





    /** Look up NetworkBandwidth and create a new one if it doesn't exist */

    /** Look up NetworkBandwidth and create a new one if it doesn't exist */

    @VisibleForTesting

    @VisibleForTesting

    @NonNull

    @NonNull

    public NetworkBandwidth lookupNetwork(String plmn, int tac, String dataRat) {

    public NetworkBandwidth lookupNetwork(@NonNull String plmn, int tac, String dataRat) {

        if (plmn == null || dataRat.equals(

        if (dataRat.equals(

                TelephonyManager.getNetworkTypeName(TelephonyManager.NETWORK_TYPE_UNKNOWN))) {

                TelephonyManager.getNetworkTypeName(TelephonyManager.NETWORK_TYPE_UNKNOWN))) {

            return mPlaceholderNetwork;

            return mPlaceholderNetwork;

        }

        }
@@ -1180,7 +1191,9 @@ public class LinkBandwidthEstimator extends Handler { 
    /** A class holding link bandwidth related stats */

    /** A class holding link bandwidth related stats */

    @VisibleForTesting

    @VisibleForTesting

    public class NetworkBandwidth {

    public class NetworkBandwidth {



        private final String mKey;

        private final String mKey;



        NetworkBandwidth(String key) {

        NetworkBandwidth(String key) {

            mKey = key;

            mKey = key;

        }

        }
@@ -1276,5 +1289,4 @@ public class LinkBandwidthEstimator extends Handler { 
        pw.println();

        pw.println();

        pw.flush();

        pw.flush();

    }

    }



}
 
}