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Commit f79a34d8 authored by Erik Kline's avatar Erik Kline
Browse files

Flatten the transitions to tethering and hotspot. 

The previous version could trigger a Log.wtf() if an error occured within
ServingState.enter() that caused a transition while a tranistion was
already in flight.

Test: as follows
    - build
    - flashed
    - booted
    - "runtest frameworks-net" passes
Bug: 31466854

Change-Id: I66a47caf22e39ab4ad7f4ddd60940e9fe1580729
parent 24299f5b

services/core/java/com/android/server/connectivity/tethering/TetherInterfaceStateMachine.java

+34 −12
Original line number Diff line number Diff line
@@ -78,7 +78,6 @@ public class TetherInterfaceStateMachine extends StateMachine { 
    public static final int CMD_IPV6_TETHER_UPDATE          = BASE_IFACE + 13;



    private final State mInitialState;

    private final State mServingState;

    private final State mLocalHotspotState;

    private final State mTetheredState;

    private final State mUnavailableState;
@@ -107,14 +106,12 @@ public class TetherInterfaceStateMachine extends StateMachine { 
        mLastError = ConnectivityManager.TETHER_ERROR_NO_ERROR;



        mInitialState = new InitialState();

        mServingState = new ServingState();

        mLocalHotspotState = new LocalHotspotState();

        mTetheredState = new TetheredState();

        mUnavailableState = new UnavailableState();

        addState(mInitialState);

        addState(mServingState);

            addState(mLocalHotspotState, mServingState);

            addState(mTetheredState, mServingState);

        addState(mLocalHotspotState);

        addState(mTetheredState);

        addState(mUnavailableState);



        setInitialState(mInitialState);
@@ -222,12 +219,11 @@ public class TetherInterfaceStateMachine extends StateMachine { 
        }

    }



    class ServingState extends State {

    class BaseServingState extends State {

        @Override

        public void enter() {

            if (!configureIfaceIp(true)) {

                mLastError = ConnectivityManager.TETHER_ERROR_IFACE_CFG_ERROR;

                transitionTo(mInitialState);

                return;

            }
@@ -236,12 +232,13 @@ public class TetherInterfaceStateMachine extends StateMachine { 
            } catch (Exception e) {

                Log.e(TAG, "Error Tethering: " + e.toString());

                mLastError = ConnectivityManager.TETHER_ERROR_TETHER_IFACE_ERROR;

                transitionTo(mInitialState);

                return;

            }



            if (!mIPv6TetherSvc.start()) {

                Log.e(TAG, "Failed to start IPv6TetheringInterfaceServices");

                // TODO: Make this a fatal error once Bluetooth IPv6 is sorted.

                return;

            }

        }
@@ -254,9 +251,9 @@ public class TetherInterfaceStateMachine extends StateMachine { 


            try {

                mNMService.untetherInterface(mIfaceName);

            } catch (Exception ee) {

            } catch (Exception e) {

                mLastError = ConnectivityManager.TETHER_ERROR_UNTETHER_IFACE_ERROR;

                Log.e(TAG, "Failed to untether interface: " + ee.toString());

                Log.e(TAG, "Failed to untether interface: " + e.toString());

            }



            configureIfaceIp(false);
@@ -293,15 +290,27 @@ public class TetherInterfaceStateMachine extends StateMachine { 
        }

    }



    class LocalHotspotState extends State {

    // Handling errors in BaseServingState.enter() by transitioning is

    // problematic because transitioning during a multi-state jump yields

    // a Log.wtf(). Ultimately, there should be only one ServingState,

    // and forwarding and NAT rules should be handled by a coordinating

    // functional element outside of TetherInterfaceStateMachine.

    class LocalHotspotState extends BaseServingState {

        @Override

        public void enter() {

            super.enter();

            if (mLastError != ConnectivityManager.TETHER_ERROR_NO_ERROR) {

                transitionTo(mInitialState);

            }



            if (DBG) Log.d(TAG, "Local hotspot " + mIfaceName);

            sendInterfaceState(IControlsTethering.STATE_LOCAL_HOTSPOT);

        }



        @Override

        public boolean processMessage(Message message) {

            if (super.processMessage(message)) return true;



            maybeLogMessage(this, message.what);

            switch (message.what) {

                case CMD_TETHER_REQUESTED:
@@ -317,9 +326,19 @@ public class TetherInterfaceStateMachine extends StateMachine { 
        }

    }



    class TetheredState extends State {

    // Handling errors in BaseServingState.enter() by transitioning is

    // problematic because transitioning during a multi-state jump yields

    // a Log.wtf(). Ultimately, there should be only one ServingState,

    // and forwarding and NAT rules should be handled by a coordinating

    // functional element outside of TetherInterfaceStateMachine.

    class TetheredState extends BaseServingState {

        @Override

        public void enter() {

            super.enter();

            if (mLastError != ConnectivityManager.TETHER_ERROR_NO_ERROR) {

                transitionTo(mInitialState);

            }



            if (DBG) Log.d(TAG, "Tethered " + mIfaceName);

            sendInterfaceState(IControlsTethering.STATE_TETHERED);

        }
@@ -327,6 +346,7 @@ public class TetherInterfaceStateMachine extends StateMachine { 
        @Override

        public void exit() {

            cleanupUpstream();

            super.exit();

        }



        private void cleanupUpstream() {
@@ -361,6 +381,8 @@ public class TetherInterfaceStateMachine extends StateMachine { 


        @Override

        public boolean processMessage(Message message) {

            if (super.processMessage(message)) return true;



            maybeLogMessage(this, message.what);

            boolean retValue = true;

            switch (message.what) {