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Commit e8c548fd authored by Benedict Wong's avatar Benedict Wong
Browse files

Ensure VcnGatewayConnection#isQuitting never gets unset after being set 

This change ensures that the VcnGatewayConnection can never abort a
quitting command; specifically, if a non-quitting disconnect request is
processed after a quitting disconnect request, the isQuitting value MUST
continue to stay set (as true).

Failure to OR the values results in orphaned VcnGatewayConnection(s),
and the VCN network thrashing.

Additionally reduce verbosity of local logs, to ensure it better
captures failures and logWtf(s)

Bug: 192776413
Test: atest FrameworksVcnTests
Change-Id: Iec8dae701838794261957609bae4e270eaa9cdc7
parent 9ffdbe8b

services/core/java/com/android/server/VcnManagementService.java

+3 −4
Original line number Diff line number Diff line
@@ -520,12 +520,14 @@ public class VcnManagementService extends IVcnManagementService.Stub { 


    @GuardedBy("mLock")

    private void stopVcnLocked(@NonNull ParcelUuid uuidToTeardown) {

        final Vcn vcnToTeardown = mVcns.remove(uuidToTeardown);

        // Remove in 2 steps. Make sure teardownAsync is triggered before removing from the map.

        final Vcn vcnToTeardown = mVcns.get(uuidToTeardown);

        if (vcnToTeardown == null) {

            return;

        }



        vcnToTeardown.teardownAsynchronously();

        mVcns.remove(uuidToTeardown);



        // Now that the VCN is removed, notify all registered listeners to refresh their

        // UnderlyingNetworkPolicy.
@@ -1011,18 +1013,15 @@ public class VcnManagementService extends IVcnManagementService.Stub { 
    private void logVdbg(String msg) {

        if (VDBG) {

            Slog.v(TAG, msg);

            LOCAL_LOG.log(TAG + " VDBG: " + msg);

        }

    }



    private void logDbg(String msg) {

        Slog.d(TAG, msg);

        LOCAL_LOG.log(TAG + " DBG: " + msg);

    }



    private void logDbg(String msg, Throwable tr) {

        Slog.d(TAG, msg, tr);

        LOCAL_LOG.log(TAG + " DBG: " + msg + tr);

    }



    private void logErr(String msg) {

services/core/java/com/android/server/vcn/Vcn.java

+0 −3
Original line number Diff line number Diff line
@@ -528,18 +528,15 @@ public class Vcn extends Handler { 
    private void logVdbg(String msg) {

        if (VDBG) {

            Slog.v(TAG, getLogPrefix() + msg);

            LOCAL_LOG.log(getLogPrefix() + "VDBG: " + msg);

        }

    }



    private void logDbg(String msg) {

        Slog.d(TAG, getLogPrefix() + msg);

        LOCAL_LOG.log(getLogPrefix() + "DBG: " + msg);

    }



    private void logDbg(String msg, Throwable tr) {

        Slog.d(TAG, getLogPrefix() + msg, tr);

        LOCAL_LOG.log(getLogPrefix() + "DBG: " + msg + tr);

    }



    private void logErr(String msg) {

services/core/java/com/android/server/vcn/VcnGatewayConnection.java

+23 −15
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ import com.android.server.vcn.UnderlyingNetworkTracker.UnderlyingNetworkTrackerC 
import com.android.server.vcn.Vcn.VcnGatewayStatusCallback;

import com.android.server.vcn.util.LogUtils;

import com.android.server.vcn.util.MtuUtils;

import com.android.server.vcn.util.OneWayBoolean;



import java.io.IOException;

import java.net.Inet4Address;
@@ -551,8 +552,13 @@ public class VcnGatewayConnection extends StateMachine { 
     * <p>This variable is false for the lifecycle of the VcnGatewayConnection, until a command to

     * teardown has been received. This may be flipped due to events such as the Network becoming

     * unwanted, the owning VCN entering safe mode, or an irrecoverable internal failure.

     *

     * <p>WARNING: Assignments to this MUST ALWAYS (except for testing) use the or operator ("|="),

     * otherwise the flag may be flipped back to false after having been set to true. This could

     * lead to a case where the Vcn parent instance has commanded a teardown, but a spurious

     * non-quitting disconnect request could flip this back to true.

     */

    private boolean mIsQuitting = false;

    private OneWayBoolean mIsQuitting = new OneWayBoolean();



    /**

     * Whether the VcnGatewayConnection is in safe mode.
@@ -794,7 +800,7 @@ public class VcnGatewayConnection extends StateMachine { 
    private void acquireWakeLock() {

        mVcnContext.ensureRunningOnLooperThread();



        if (!mIsQuitting) {

        if (!mIsQuitting.getValue()) {

            mWakeLock.acquire();



            logVdbg("Wakelock acquired: " + mWakeLock);
@@ -1297,7 +1303,9 @@ public class VcnGatewayConnection extends StateMachine { 
            // TODO(b/180526152): notify VcnStatusCallback for Network loss



            logDbg("Tearing down. Cause: " + info.reason);

            mIsQuitting = info.shouldQuit;

            if (info.shouldQuit) {

                mIsQuitting.setTrue();

            }



            teardownNetwork();
@@ -1341,7 +1349,7 @@ public class VcnGatewayConnection extends StateMachine { 
    private class DisconnectedState extends BaseState {

        @Override

        protected void enterState() {

            if (mIsQuitting) {

            if (mIsQuitting.getValue()) {

                quitNow(); // Ignore all queued events; cleanup is complete.

            }
@@ -1365,7 +1373,7 @@ public class VcnGatewayConnection extends StateMachine { 
                    break;

                case EVENT_DISCONNECT_REQUESTED:

                    if (((EventDisconnectRequestedInfo) msg.obj).shouldQuit) {

                        mIsQuitting = true;

                        mIsQuitting.setTrue();



                        quitNow();

                    }
@@ -1451,7 +1459,10 @@ public class VcnGatewayConnection extends StateMachine { 
                    break;

                case EVENT_DISCONNECT_REQUESTED:

                    EventDisconnectRequestedInfo info = ((EventDisconnectRequestedInfo) msg.obj);

                    mIsQuitting = info.shouldQuit;

                    if (info.shouldQuit) {

                        mIsQuitting.setTrue();

                    }



                    teardownNetwork();



                    if (info.reason.equals(DISCONNECT_REASON_UNDERLYING_NETWORK_LOST)) {
@@ -1467,7 +1478,7 @@ public class VcnGatewayConnection extends StateMachine { 
                case EVENT_SESSION_CLOSED:

                    mIkeSession = null;



                    if (!mIsQuitting && mUnderlying != null) {

                    if (!mIsQuitting.getValue() && mUnderlying != null) {

                        transitionTo(mSkipRetryTimeout ? mConnectingState : mRetryTimeoutState);

                    } else {

                        teardownNetwork();
@@ -1626,7 +1637,7 @@ public class VcnGatewayConnection extends StateMachine { 
                                teardownAsynchronously();

                            } /* networkUnwantedCallback */,

                            (status) -> {

                                if (mIsQuitting) {

                                if (mIsQuitting.getValue()) {

                                    return; // Ignore; VcnGatewayConnection quitting or already quit

                                }
@@ -2180,18 +2191,15 @@ public class VcnGatewayConnection extends StateMachine { 
    private void logVdbg(String msg) {

        if (VDBG) {

            Slog.v(TAG, getLogPrefix() + msg);

            LOCAL_LOG.log(getLogPrefix() + "VDBG: " + msg);

        }

    }



    private void logDbg(String msg) {

        Slog.d(TAG, getLogPrefix() + msg);

        LOCAL_LOG.log(getLogPrefix() + "DBG: " + msg);

    }



    private void logDbg(String msg, Throwable tr) {

        Slog.d(TAG, getLogPrefix() + msg, tr);

        LOCAL_LOG.log(getLogPrefix() + "DBG: " + msg + tr);

    }



    private void logWarn(String msg) {
@@ -2238,7 +2246,7 @@ public class VcnGatewayConnection extends StateMachine { 
                        + (getCurrentState() == null

                                ? null

                                : getCurrentState().getClass().getSimpleName()));

        pw.println("mIsQuitting: " + mIsQuitting);

        pw.println("mIsQuitting: " + mIsQuitting.getValue());

        pw.println("mIsInSafeMode: " + mIsInSafeMode);

        pw.println("mCurrentToken: " + mCurrentToken);

        pw.println("mFailedAttempts: " + mFailedAttempts);
@@ -2275,12 +2283,12 @@ public class VcnGatewayConnection extends StateMachine { 


    @VisibleForTesting(visibility = Visibility.PRIVATE)

    boolean isQuitting() {

        return mIsQuitting;

        return mIsQuitting.getValue();

    }



    @VisibleForTesting(visibility = Visibility.PRIVATE)

    void setIsQuitting(boolean isQuitting) {

        mIsQuitting = isQuitting;

    void setQuitting() {

        mIsQuitting.setTrue();

    }



    @VisibleForTesting(visibility = Visibility.PRIVATE)

services/core/java/com/android/server/vcn/util/OneWayBoolean.java

0 → 100644
+39 −0
Original line number Diff line number Diff line 
/*

 * 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.vcn.util;



/**

 * OneWayBoolean is an abstraction for a boolean that MUST only ever be flipped from false to true

 *

 * <p>This class allows the providing of a guarantee that a flag will never be flipped back after

 * being set.

 *

 * @hide

 */

public class OneWayBoolean {

    private boolean mValue = false;



    /** Get boolean value. */

    public boolean getValue() {

        return mValue;

    }



    /** Sets the value to true. */

    public void setTrue() {

        mValue = true;

    }

}

tests/vcn/java/com/android/server/vcn/VcnGatewayConnectionConnectedStateTest.java

+4 −0
Original line number Diff line number Diff line
@@ -578,6 +578,10 @@ public class VcnGatewayConnectionConnectedStateTest extends VcnGatewayConnection 
        mGatewayConnection.teardownAsynchronously();

        mTestLooper.dispatchAll();



        // Verify that sending a non-quitting disconnect request does not unset the isQuitting flag

        mGatewayConnection.sendDisconnectRequestedAndAcquireWakelock("TEST", false);

        mTestLooper.dispatchAll();



        assertEquals(mGatewayConnection.mDisconnectingState, mGatewayConnection.getCurrentState());

        assertTrue(mGatewayConnection.isQuitting());

    }