Get rid of BpfCoordinator#mPollingStarted

Refactor IpServer/BpfCoordinator to remove mPollingStarted, and just
maintain the invariant that "data usage polling and conntrack
monitoring are running iff at least one IpServer is serving".

Test: atest TetheringTests
Bug: 294025403
Change-Id: I55064ee78e1cda12ad76b7c31496d760dcffdd76
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 9e0c970..6c8ff05 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -1141,14 +1141,6 @@
         }
     }
 
-    private void startConntrackMonitoring() {
-        mBpfCoordinator.startMonitoring(this);
-    }
-
-    private void stopConntrackMonitoring() {
-        mBpfCoordinator.stopMonitoring(this);
-    }
-
     abstract class BaseServingState extends State {
         private final int mDesiredInterfaceState;
 
@@ -1158,7 +1150,7 @@
 
         @Override
         public void enter() {
-            startConntrackMonitoring();
+            mBpfCoordinator.addIpServer(IpServer.this);
 
             startServingInterface();
 
@@ -1226,7 +1218,7 @@
             }
 
             stopIPv4();
-            stopConntrackMonitoring();
+            mBpfCoordinator.removeIpServer(IpServer.this);
 
             resetLinkProperties();
 
diff --git a/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java b/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
index 00d9152..2374868 100644
--- a/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
+++ b/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
@@ -189,14 +189,6 @@
     // to make it simpler. See also TetheringConfiguration.
     private final boolean mIsBpfEnabled;
 
-    // Tracks whether BPF tethering is started or not. This is set by tethering before it
-    // starts the first IpServer and is cleared by tethering shortly before the last IpServer
-    // is stopped. Note that rule updates (especially deletions, but sometimes additions as
-    // well) may arrive when this is false. If they do, they must be communicated to netd.
-    // Changes in data limits may also arrive when this is false, and if they do, they must
-    // also be communicated to netd.
-    private boolean mPollingStarted = false;
-
     // Tracking remaining alert quota. Unlike limit quota is subject to interface, the alert
     // quota is interface independent and global for tether offload.
     private long mRemainingAlertQuota = QUOTA_UNLIMITED;
@@ -279,9 +271,6 @@
     private final HashMap<IpServer, HashMap<Inet4Address, ClientInfo>>
             mTetherClients = new HashMap<>();
 
-    // Set for which downstream is monitoring the conntrack netlink message.
-    private final Set<IpServer> mMonitoringIpServers = new HashSet<>();
-
     // Map of upstream interface IPv4 address to interface index.
     // TODO: consider making the key to be unique because the upstream address is not unique. It
     // is okay for now because there have only one upstream generally.
@@ -303,16 +292,19 @@
     @Nullable
     private UpstreamInfo mIpv4UpstreamInfo = null;
 
+    // The IpServers that are currently served by BpfCoordinator.
+    private final ArraySet<IpServer> mServedIpServers = new ArraySet<>();
+
     // Runnable that used by scheduling next polling of stats.
     private final Runnable mScheduledPollingStats = () -> {
         updateForwardedStats();
-        maybeSchedulePollingStats();
+        schedulePollingStats();
     };
 
     // Runnable that used by scheduling next refreshing of conntrack timeout.
     private final Runnable mScheduledConntrackTimeoutUpdate = () -> {
         refreshAllConntrackTimeouts();
-        maybeScheduleConntrackTimeoutUpdate();
+        scheduleConntrackTimeoutUpdate();
     };
 
     // TODO: add BpfMap<TetherDownstream64Key, TetherDownstream64Value> retrieving function.
@@ -504,37 +496,25 @@
     }
 
     /**
-     * Start BPF tethering offload stats polling when the first upstream is started.
+     * Start BPF tethering offload stats and conntrack timeout polling.
      * Note that this can be only called on handler thread.
-     * TODO: Perhaps check BPF support before starting.
-     * TODO: Start the stats polling only if there is any client on the downstream.
      */
-    public void startPolling() {
-        if (mPollingStarted) return;
+    private void startStatsAndConntrackTimeoutPolling() {
+        schedulePollingStats();
+        scheduleConntrackTimeoutUpdate();
 
-        if (!isUsingBpf()) {
-            mLog.i("BPF is not using");
-            return;
-        }
-
-        mPollingStarted = true;
-        maybeSchedulePollingStats();
-        maybeScheduleConntrackTimeoutUpdate();
-
-        mLog.i("Polling started");
+        mLog.i("Polling started.");
     }
 
     /**
-     * Stop BPF tethering offload stats polling.
+     * Stop BPF tethering offload stats and conntrack timeout polling.
      * The data limit cleanup and the tether stats maps cleanup are not implemented here.
      * These cleanups rely on all IpServers calling #removeIpv6DownstreamRule. After the
      * last rule is removed from the upstream, #removeIpv6DownstreamRule does the cleanup
      * functionality.
      * Note that this can be only called on handler thread.
      */
-    public void stopPolling() {
-        if (!mPollingStarted) return;
-
+    private void stopStatsAndConntrackTimeoutPolling() {
         // Stop scheduled polling conntrack timeout.
         if (mHandler.hasCallbacks(mScheduledConntrackTimeoutUpdate)) {
             mHandler.removeCallbacks(mScheduledConntrackTimeoutUpdate);
@@ -544,9 +524,8 @@
             mHandler.removeCallbacks(mScheduledPollingStats);
         }
         updateForwardedStats();
-        mPollingStarted = false;
 
-        mLog.i("Polling stopped");
+        mLog.i("Polling stopped.");
     }
 
     /**
@@ -567,7 +546,6 @@
 
     /**
      * Start conntrack message monitoring.
-     * Note that this can be only called on handler thread.
      *
      * TODO: figure out a better logging for non-interesting conntrack message.
      * For example, the following logging is an IPCTNL_MSG_CT_GET message but looks scary.
@@ -587,45 +565,23 @@
      * +------------------+--------------------------------------------------------+
      * See NetlinkMonitor#handlePacket, NetlinkMessage#parseNfMessage.
      */
-    public void startMonitoring(@NonNull final IpServer ipServer) {
+    private void startConntrackMonitoring() {
         // TODO: Wrap conntrackMonitor starting function into mBpfCoordinatorShim.
-        if (!isUsingBpf() || !mDeps.isAtLeastS()) return;
+        if (!mDeps.isAtLeastS()) return;
 
-        if (mMonitoringIpServers.contains(ipServer)) {
-            Log.wtf(TAG, "The same downstream " + ipServer.interfaceName()
-                    + " should not start monitoring twice.");
-            return;
-        }
-
-        if (mMonitoringIpServers.isEmpty()) {
-            mConntrackMonitor.start();
-            mLog.i("Monitoring started");
-        }
-
-        mMonitoringIpServers.add(ipServer);
+        mConntrackMonitor.start();
+        mLog.i("Conntrack monitoring started.");
     }
 
     /**
      * Stop conntrack event monitoring.
-     * Note that this can be only called on handler thread.
      */
-    public void stopMonitoring(@NonNull final IpServer ipServer) {
+    private void stopConntrackMonitoring() {
         // TODO: Wrap conntrackMonitor stopping function into mBpfCoordinatorShim.
-        if (!isUsingBpf() || !mDeps.isAtLeastS()) return;
-
-        // Ignore stopping monitoring if the monitor has never started for a given IpServer.
-        if (!mMonitoringIpServers.contains(ipServer)) {
-            mLog.e("Ignore stopping monitoring because monitoring has never started for "
-                    + ipServer.interfaceName());
-            return;
-        }
-
-        mMonitoringIpServers.remove(ipServer);
-
-        if (!mMonitoringIpServers.isEmpty()) return;
+        if (!mDeps.isAtLeastS()) return;
 
         mConntrackMonitor.stop();
-        mLog.i("Monitoring stopped");
+        mLog.i("Conntrack monitoring stopped.");
     }
 
     /**
@@ -886,6 +842,46 @@
     }
 
     /**
+     * Register an IpServer (downstream).
+     * Note that this can be only called on handler thread.
+     */
+    public void addIpServer(@NonNull final IpServer ipServer) {
+        if (!isUsingBpf()) return;
+        if (mServedIpServers.contains(ipServer)) {
+            Log.wtf(TAG, "The same downstream " + ipServer.interfaceName()
+                    + " should not add twice.");
+            return;
+        }
+
+        // Start monitoring and polling when the first IpServer is added.
+        if (mServedIpServers.isEmpty()) {
+            startStatsAndConntrackTimeoutPolling();
+            startConntrackMonitoring();
+        }
+        mServedIpServers.add(ipServer);
+    }
+
+    /**
+     * Unregister an IpServer (downstream).
+     * Note that this can be only called on handler thread.
+     */
+    public void removeIpServer(@NonNull final IpServer ipServer) {
+        if (!isUsingBpf()) return;
+        if (!mServedIpServers.contains(ipServer)) {
+            mLog.e("Ignore removing because IpServer has never started for "
+                    + ipServer.interfaceName());
+            return;
+        }
+        mServedIpServers.remove(ipServer);
+
+        // Stop monitoring and polling when the last IpServer is removed.
+        if (mServedIpServers.isEmpty()) {
+            stopStatsAndConntrackTimeoutPolling();
+            stopConntrackMonitoring();
+        }
+    }
+
+    /**
      * Clear all forwarding IPv4 rules for a given client.
      * Note that this can be only called on handler thread.
      */
@@ -1136,7 +1132,7 @@
         // Note that EthernetTetheringTest#isTetherConfigBpfOffloadEnabled relies on
         // "mIsBpfEnabled" to check tethering config via dumpsys. Beware of the change if any.
         pw.println("mIsBpfEnabled: " + mIsBpfEnabled);
-        pw.println("Polling " + (mPollingStarted ? "started" : "not started"));
+        pw.println("Polling " + (mServedIpServers.isEmpty() ? "not started" : "started"));
         pw.println("Stats provider " + (mStatsProvider != null
                 ? "registered" : "not registered"));
         pw.println("Upstream quota: " + mInterfaceQuotas.toString());
@@ -2365,9 +2361,7 @@
         });
     }
 
-    private void maybeSchedulePollingStats() {
-        if (!mPollingStarted) return;
-
+    private void schedulePollingStats() {
         if (mHandler.hasCallbacks(mScheduledPollingStats)) {
             mHandler.removeCallbacks(mScheduledPollingStats);
         }
@@ -2375,9 +2369,7 @@
         mHandler.postDelayed(mScheduledPollingStats, getPollingInterval());
     }
 
-    private void maybeScheduleConntrackTimeoutUpdate() {
-        if (!mPollingStarted) return;
-
+    private void scheduleConntrackTimeoutUpdate() {
         if (mHandler.hasCallbacks(mScheduledConntrackTimeoutUpdate)) {
             mHandler.removeCallbacks(mScheduledConntrackTimeoutUpdate);
         }
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index d85d92f..8e4b3a5 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -2069,9 +2069,6 @@
                     chooseUpstreamType(true);
                     mTryCell = false;
                 }
-
-                // TODO: Check the upstream interface if it is managed by BPF offload.
-                mBpfCoordinator.startPolling();
             }
 
             @Override
@@ -2085,7 +2082,6 @@
                     reportUpstreamChanged(null);
                     mNotificationUpdater.onUpstreamCapabilitiesChanged(null);
                 }
-                mBpfCoordinator.stopPolling();
                 mTetheringMetrics.cleanup();
             }
 
diff --git a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
index a7064e8..316ccd7 100644
--- a/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
+++ b/Tethering/tests/unit/src/android/net/ip/IpServerTest.java
@@ -242,6 +242,7 @@
             throws Exception {
         initStateMachine(interfaceType, usingLegacyDhcp, usingBpfOffload);
         dispatchCommand(IpServer.CMD_TETHER_REQUESTED, STATE_TETHERED);
+        verify(mBpfCoordinator).addIpServer(mIpServer);
         if (upstreamIface != null) {
             InterfaceParams interfaceParams = mDependencies.getInterfaceParams(upstreamIface);
             assertNotNull("missing upstream interface: " + upstreamIface, interfaceParams);
@@ -570,7 +571,7 @@
                 argThat(cfg -> IFACE_NAME.equals(cfg.ifName)));
         inOrder.verify(mAddressCoordinator).releaseDownstream(any());
         inOrder.verify(mBpfCoordinator).tetherOffloadClientClear(mIpServer);
-        inOrder.verify(mBpfCoordinator).stopMonitoring(mIpServer);
+        inOrder.verify(mBpfCoordinator).removeIpServer(mIpServer);
         inOrder.verify(mCallback).updateInterfaceState(
                 mIpServer, STATE_AVAILABLE, TETHER_ERROR_NO_ERROR);
         inOrder.verify(mCallback).updateLinkProperties(
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
index 47ecf58..32c1bd0 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
@@ -664,6 +664,11 @@
 
     @NonNull
     private BpfCoordinator makeBpfCoordinator() throws Exception {
+        return makeBpfCoordinator(true /* addDefaultIpServer */);
+    }
+
+    @NonNull
+    private BpfCoordinator makeBpfCoordinator(boolean addDefaultIpServer) throws Exception {
         // mStatsManager will be invoked twice if BpfCoordinator is created the second time.
         clearInvocations(mStatsManager);
         final BpfCoordinator coordinator = new BpfCoordinator(mDeps);
@@ -681,6 +686,10 @@
         mTetherStatsProviderCb = new TestableNetworkStatsProviderCbBinder();
         mTetherStatsProvider.setProviderCallbackBinder(mTetherStatsProviderCb);
 
+        if (addDefaultIpServer) {
+            coordinator.addIpServer(mIpServer);
+        }
+
         return coordinator;
     }
 
@@ -1056,7 +1065,6 @@
 
         doReturn(usingApiS).when(mDeps).isAtLeastS();
         final BpfCoordinator coordinator = makeBpfCoordinator();
-        coordinator.startPolling();
 
         final String mobileIface = "rmnet_data0";
         final Integer mobileIfIndex = 100;
@@ -1092,7 +1100,6 @@
         setupFunctioningNetdInterface();
 
         final BpfCoordinator coordinator = makeBpfCoordinator();
-        coordinator.startPolling();
 
         final String wlanIface = "wlan0";
         final Integer wlanIfIndex = 100;
@@ -1148,7 +1155,7 @@
         // [3] Stop coordinator.
         // Shutdown the coordinator and clear the invocation history, especially the
         // tetherOffloadGetStats() calls.
-        coordinator.stopPolling();
+        coordinator.removeIpServer(mIpServer);
         clearStatsInvocations();
 
         // Verify the polling update thread stopped.
@@ -1162,7 +1169,6 @@
         setupFunctioningNetdInterface();
 
         final BpfCoordinator coordinator = makeBpfCoordinator();
-        coordinator.startPolling();
 
         final String mobileIface = "rmnet_data0";
         final Integer mobileIfIndex = 100;
@@ -1532,7 +1538,6 @@
         // #makeBpfCoordinator for testing.
         // See #testBpfDisabledbyNoBpfDownstream6Map.
         final BpfCoordinator coordinator = makeBpfCoordinator();
-        coordinator.startPolling();
 
         // The tether stats polling task should not be scheduled.
         mTestLooper.moveTimeForward(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS);
@@ -1753,18 +1758,14 @@
         final BpfCoordinator coordinator = makeBpfCoordinator();
 
         // [1] The default polling interval.
-        coordinator.startPolling();
         assertEquals(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS, coordinator.getPollingInterval());
-        coordinator.stopPolling();
 
         // [2] Expect the invalid polling interval isn't applied. The valid range of interval is
         // DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS..max_long.
         for (final int interval
                 : new int[] {0, 100, DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS - 1}) {
             when(mTetherConfig.getOffloadPollInterval()).thenReturn(interval);
-            coordinator.startPolling();
             assertEquals(DEFAULT_TETHER_OFFLOAD_POLL_INTERVAL_MS, coordinator.getPollingInterval());
-            coordinator.stopPolling();
         }
 
         // [3] Set a specific polling interval which is larger than default value.
@@ -1772,7 +1773,6 @@
         // approximation is used to verify the scheduled time of the polling thread.
         final int pollingInterval = 100_000;
         when(mTetherConfig.getOffloadPollInterval()).thenReturn(pollingInterval);
-        coordinator.startPolling();
 
         // Expect the specific polling interval to be applied.
         assertEquals(pollingInterval, coordinator.getPollingInterval());
@@ -1800,19 +1800,19 @@
     public void testStartStopConntrackMonitoring() throws Exception {
         setupFunctioningNetdInterface();
 
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
 
         // [1] Don't stop monitoring if it has never started.
-        coordinator.stopMonitoring(mIpServer);
+        coordinator.removeIpServer(mIpServer);
         verify(mConntrackMonitor, never()).stop();
 
         // [2] Start monitoring.
-        coordinator.startMonitoring(mIpServer);
+        coordinator.addIpServer(mIpServer);
         verify(mConntrackMonitor).start();
         clearInvocations(mConntrackMonitor);
 
         // [3] Stop monitoring.
-        coordinator.stopMonitoring(mIpServer);
+        coordinator.removeIpServer(mIpServer);
         verify(mConntrackMonitor).stop();
     }
 
@@ -1823,12 +1823,12 @@
     public void testStartStopConntrackMonitoring_R() throws Exception {
         setupFunctioningNetdInterface();
 
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
 
-        coordinator.startMonitoring(mIpServer);
+        coordinator.addIpServer(mIpServer);
         verify(mConntrackMonitor, never()).start();
 
-        coordinator.stopMonitoring(mIpServer);
+        coordinator.removeIpServer(mIpServer);
         verify(mConntrackMonitor, never()).stop();
     }
 
@@ -1837,23 +1837,23 @@
     public void testStartStopConntrackMonitoringWithTwoDownstreamIfaces() throws Exception {
         setupFunctioningNetdInterface();
 
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
 
         // [1] Start monitoring at the first IpServer adding.
-        coordinator.startMonitoring(mIpServer);
+        coordinator.addIpServer(mIpServer);
         verify(mConntrackMonitor).start();
         clearInvocations(mConntrackMonitor);
 
         // [2] Don't start monitoring at the second IpServer adding.
-        coordinator.startMonitoring(mIpServer2);
+        coordinator.addIpServer(mIpServer2);
         verify(mConntrackMonitor, never()).start();
 
         // [3] Don't stop monitoring if any downstream interface exists.
-        coordinator.stopMonitoring(mIpServer2);
+        coordinator.removeIpServer(mIpServer2);
         verify(mConntrackMonitor, never()).stop();
 
         // [4] Stop monitoring if no downstream exists.
-        coordinator.stopMonitoring(mIpServer);
+        coordinator.removeIpServer(mIpServer);
         verify(mConntrackMonitor).stop();
     }
 
@@ -2087,7 +2087,6 @@
                 .startMocking();
         try {
             final BpfCoordinator coordinator = makeBpfCoordinator();
-            coordinator.startPolling();
             bpfMap.insertEntry(tcpKey, tcpValue);
             bpfMap.insertEntry(udpKey, udpValue);
 
@@ -2116,7 +2115,7 @@
             ExtendedMockito.clearInvocations(staticMockMarker(NetlinkUtils.class));
 
             // [3] Don't refresh conntrack timeout if polling stopped.
-            coordinator.stopPolling();
+            coordinator.removeIpServer(mIpServer);
             mTestLooper.moveTimeForward(CONNTRACK_TIMEOUT_UPDATE_INTERVAL_MS);
             waitForIdle();
             ExtendedMockito.verifyNoMoreInteractions(staticMockMarker(NetlinkUtils.class));
@@ -2854,7 +2853,7 @@
     public void addRemoveIpv6ForwardingRules() throws Exception {
         final int myIfindex = DOWNSTREAM_IFINDEX;
         final int notMyIfindex = myIfindex - 1;
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
         final IpServer ipServer = makeAndStartIpServer(DOWNSTREAM_IFACE, coordinator);
 
         resetNetdAndBpfMaps();
@@ -3003,7 +3002,7 @@
 
         // [1] Enable BPF offload.
         // A neighbor that is added or deleted causes the rule to be added or removed.
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
         final IpServer ipServer = makeAndStartIpServer(DOWNSTREAM_IFACE, coordinator);
         resetNetdAndBpfMaps();
 
@@ -3029,7 +3028,7 @@
         // [2] Disable BPF offload.
         // A neighbor that is added or deleted doesn’t cause the rule to be added or removed.
         when(mTetherConfig.isBpfOffloadEnabled()).thenReturn(false);
-        final BpfCoordinator coordinator2 = makeBpfCoordinator();
+        final BpfCoordinator coordinator2 = makeBpfCoordinator(false /* addDefaultIpServer */);
         final IpServer ipServer2 = makeAndStartIpServer(DOWNSTREAM_IFACE, coordinator2);
         verifyNoUpstreamIpv6ForwardingChange(null);
         resetNetdAndBpfMaps();
@@ -3052,7 +3051,7 @@
     @Test
     public void doesNotStartIpNeighborMonitorIfBpfOffloadDisabled() throws Exception {
         when(mTetherConfig.isBpfOffloadEnabled()).thenReturn(false);
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
         final IpServer ipServer = makeAndStartIpServer(DOWNSTREAM_IFACE, coordinator);
 
         // IP neighbor monitor doesn't start if BPF offload is disabled.
@@ -3061,7 +3060,7 @@
 
     @Test
     public void testSkipVirtualNetworkInBpf() throws Exception {
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
         final IpServer ipServer = makeAndStartIpServer(DOWNSTREAM_IFACE, coordinator);
         final LinkProperties v6Only = new LinkProperties();
         v6Only.setInterfaceName(IPSEC_IFACE);
@@ -3079,7 +3078,7 @@
 
     @Test
     public void addRemoveTetherClient() throws Exception {
-        final BpfCoordinator coordinator = makeBpfCoordinator();
+        final BpfCoordinator coordinator = makeBpfCoordinator(false /* addDefaultIpServer */);
         final IpServer ipServer = makeAndStartIpServer(DOWNSTREAM_IFACE, coordinator);
         final int myIfindex = DOWNSTREAM_IFINDEX;
         final int notMyIfindex = myIfindex - 1;