diff --git a/Tethering/common/TetheringLib/jarjar-rules.txt b/Tethering/common/TetheringLib/jarjar-rules.txt
index 35e0f88..1403bba 100644
--- a/Tethering/common/TetheringLib/jarjar-rules.txt
+++ b/Tethering/common/TetheringLib/jarjar-rules.txt
@@ -1 +1,2 @@
 rule android.annotation.** com.android.networkstack.tethering.annotation.@1
+rule com.android.internal.annotations.** com.android.networkstack.tethering.annotation.@1
\ No newline at end of file
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
index 8dacecc..53a358f 100644
--- a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
@@ -30,6 +30,9 @@
 import android.util.ArrayMap;
 import android.util.Log;
 
+import com.android.internal.annotations.GuardedBy;
+
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -37,6 +40,7 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.Executor;
+import java.util.function.Supplier;
 
 /**
  * This class provides the APIs to control the tethering service.
@@ -50,17 +54,23 @@
 public class TetheringManager {
     private static final String TAG = TetheringManager.class.getSimpleName();
     private static final int DEFAULT_TIMEOUT_MS = 60_000;
+    private static final long CONNECTOR_POLL_INTERVAL_MILLIS = 200L;
 
-    private static TetheringManager sInstance;
+    @GuardedBy("mConnectorWaitQueue")
+    @Nullable
+    private ITetheringConnector mConnector;
+    @GuardedBy("mConnectorWaitQueue")
+    @NonNull
+    private final List<ConnectorConsumer> mConnectorWaitQueue = new ArrayList<>();
+    private final Supplier<IBinder> mConnectorSupplier;
 
-    private final ITetheringConnector mConnector;
     private final TetheringCallbackInternal mCallback;
     private final Context mContext;
     private final ArrayMap<TetheringEventCallback, ITetheringEventCallback>
             mTetheringEventCallbacks = new ArrayMap<>();
 
-    private TetheringConfigurationParcel mTetheringConfiguration;
-    private TetherStatesParcel mTetherStatesParcel;
+    private volatile TetheringConfigurationParcel mTetheringConfiguration;
+    private volatile TetherStatesParcel mTetherStatesParcel;
 
     /**
      * Broadcast Action: A tetherable connection has come or gone.
@@ -130,6 +140,18 @@
      */
     public static final int TETHERING_WIFI_P2P = 3;
 
+    /**
+     * Ncm local tethering type.
+     * @see #startTethering(TetheringRequest, Executor, StartTetheringCallback)
+     */
+    public static final int TETHERING_NCM = 4;
+
+    /**
+     * Ethernet tethering type.
+     * @see #startTethering(TetheringRequest, Executor, StartTetheringCallback)
+     */
+    public static final int TETHERING_ETHERNET = 5;
+
     public static final int TETHER_ERROR_NO_ERROR           = 0;
     public static final int TETHER_ERROR_UNKNOWN_IFACE      = 1;
     public static final int TETHER_ERROR_SERVICE_UNAVAIL    = 2;
@@ -150,29 +172,139 @@
     /**
      * Create a TetheringManager object for interacting with the tethering service.
      *
+     * @param context Context for the manager.
+     * @param connectorSupplier Supplier for the manager connector; may return null while the
+     *                          service is not connected.
      * {@hide}
      */
-    public TetheringManager(@NonNull final Context context, @NonNull final IBinder service) {
+    public TetheringManager(@NonNull final Context context,
+            @NonNull Supplier<IBinder> connectorSupplier) {
         mContext = context;
-        mConnector = ITetheringConnector.Stub.asInterface(service);
         mCallback = new TetheringCallbackInternal();
+        mConnectorSupplier = connectorSupplier;
 
         final String pkgName = mContext.getOpPackageName();
+
+        final IBinder connector = mConnectorSupplier.get();
+        // If the connector is available on start, do not start a polling thread. This introduces
+        // differences in the thread that sends the oneway binder calls to the service between the
+        // first few seconds after boot and later, but it avoids always having differences between
+        // the first usage of TetheringManager from a process and subsequent usages (so the
+        // difference is only on boot). On boot binder calls may be queued until the service comes
+        // up and be sent from a worker thread; later, they are always sent from the caller thread.
+        // Considering that it's just oneway binder calls, and ordering is preserved, this seems
+        // better than inconsistent behavior persisting after boot.
+        if (connector != null) {
+            mConnector = ITetheringConnector.Stub.asInterface(connector);
+        } else {
+            startPollingForConnector();
+        }
+
         Log.i(TAG, "registerTetheringEventCallback:" + pkgName);
+        getConnector(c -> c.registerTetheringEventCallback(mCallback, pkgName));
+    }
+
+    private void startPollingForConnector() {
+        new Thread(() -> {
+            while (true) {
+                try {
+                    Thread.sleep(200);
+                } catch (InterruptedException e) {
+                    // Not much to do here, the system needs to wait for the connector
+                }
+
+                final IBinder connector = mConnectorSupplier.get();
+                if (connector != null) {
+                    onTetheringConnected(ITetheringConnector.Stub.asInterface(connector));
+                    return;
+                }
+            }
+        }).start();
+    }
+
+    private interface ConnectorConsumer {
+        void onConnectorAvailable(ITetheringConnector connector) throws RemoteException;
+    }
+
+    private void onTetheringConnected(ITetheringConnector connector) {
+        // Process the connector wait queue in order, including any items that are added
+        // while processing.
+        //
+        // 1. Copy the queue to a local variable under lock.
+        // 2. Drain the local queue with the lock released (otherwise, enqueuing future commands
+        //    would block on the lock).
+        // 3. Acquire the lock again. If any new tasks were queued during step 2, goto 1.
+        //    If not, set mConnector to non-null so future tasks are run immediately, not queued.
+        //
+        // For this to work, all calls to the tethering service must use getConnector(), which
+        // ensures that tasks are added to the queue with the lock held.
+        //
+        // Once mConnector is set to non-null, it will never be null again. If the network stack
+        // process crashes, no recovery is possible.
+        // TODO: evaluate whether it is possible to recover from network stack process crashes
+        // (though in most cases the system will have crashed when the network stack process
+        // crashes).
+        do {
+            final List<ConnectorConsumer> localWaitQueue;
+            synchronized (mConnectorWaitQueue) {
+                localWaitQueue = new ArrayList<>(mConnectorWaitQueue);
+                mConnectorWaitQueue.clear();
+            }
+
+            // Allow more tasks to be added at the end without blocking while draining the queue.
+            for (ConnectorConsumer task : localWaitQueue) {
+                try {
+                    task.onConnectorAvailable(connector);
+                } catch (RemoteException e) {
+                    // Most likely the network stack process crashed, which is likely to crash the
+                    // system. Keep processing other requests but report the error loudly.
+                    Log.wtf(TAG, "Error processing request for the tethering connector", e);
+                }
+            }
+
+            synchronized (mConnectorWaitQueue) {
+                if (mConnectorWaitQueue.size() == 0) {
+                    mConnector = connector;
+                    return;
+                }
+            }
+        } while (true);
+    }
+
+    /**
+     * Asynchronously get the ITetheringConnector to execute some operation.
+     *
+     * <p>If the connector is already available, the operation will be executed on the caller's
+     * thread. Otherwise it will be queued and executed on a worker thread. The operation should be
+     * limited to performing oneway binder calls to minimize differences due to threading.
+     */
+    private void getConnector(ConnectorConsumer consumer) {
+        final ITetheringConnector connector;
+        synchronized (mConnectorWaitQueue) {
+            connector = mConnector;
+            if (connector == null) {
+                mConnectorWaitQueue.add(consumer);
+                return;
+            }
+        }
+
         try {
-            mConnector.registerTetheringEventCallback(mCallback, pkgName);
+            consumer.onConnectorAvailable(connector);
         } catch (RemoteException e) {
             throw new IllegalStateException(e);
         }
     }
 
     private interface RequestHelper {
-        void runRequest(IIntResultListener listener);
+        void runRequest(ITetheringConnector connector, IIntResultListener listener);
     }
 
+    // Used to dispatch legacy ConnectivityManager methods that expect tethering to be able to
+    // return results and perform operations synchronously.
+    // TODO: remove once there are no callers of these legacy methods.
     private class RequestDispatcher {
         private final ConditionVariable mWaiting;
-        public int mRemoteResult;
+        public volatile int mRemoteResult;
 
         private final IIntResultListener mListener = new IIntResultListener.Stub() {
                 @Override
@@ -187,7 +319,7 @@
         }
 
         int waitForResult(final RequestHelper request) {
-            request.runRequest(mListener);
+            getConnector(c -> request.runRequest(c, mListener));
             if (!mWaiting.block(DEFAULT_TIMEOUT_MS)) {
                 throw new IllegalStateException("Callback timeout");
             }
@@ -210,7 +342,7 @@
     }
 
     private class TetheringCallbackInternal extends ITetheringEventCallback.Stub {
-        private int mError = TETHER_ERROR_NO_ERROR;
+        private volatile int mError = TETHER_ERROR_NO_ERROR;
         private final ConditionVariable mWaitForCallback = new ConditionVariable();
 
         @Override
@@ -268,9 +400,9 @@
         Log.i(TAG, "tether caller:" + callerPkg);
         final RequestDispatcher dispatcher = new RequestDispatcher();
 
-        return dispatcher.waitForResult(listener -> {
+        return dispatcher.waitForResult((connector, listener) -> {
             try {
-                mConnector.tether(iface, callerPkg, listener);
+                connector.tether(iface, callerPkg, listener);
             } catch (RemoteException e) {
                 throw new IllegalStateException(e);
             }
@@ -292,9 +424,9 @@
 
         final RequestDispatcher dispatcher = new RequestDispatcher();
 
-        return dispatcher.waitForResult(listener -> {
+        return dispatcher.waitForResult((connector, listener) -> {
             try {
-                mConnector.untether(iface, callerPkg, listener);
+                connector.untether(iface, callerPkg, listener);
             } catch (RemoteException e) {
                 throw new IllegalStateException(e);
             }
@@ -318,9 +450,9 @@
 
         final RequestDispatcher dispatcher = new RequestDispatcher();
 
-        return dispatcher.waitForResult(listener -> {
+        return dispatcher.waitForResult((connector, listener) -> {
             try {
-                mConnector.setUsbTethering(enable, callerPkg, listener);
+                connector.setUsbTethering(enable, callerPkg, listener);
             } catch (RemoteException e) {
                 throw new IllegalStateException(e);
             }
@@ -455,11 +587,7 @@
                 });
             }
         };
-        try {
-            mConnector.startTethering(request.getParcel(), callerPkg, listener);
-        } catch (RemoteException e) {
-            throw new IllegalStateException(e);
-        }
+        getConnector(c -> c.startTethering(request.getParcel(), callerPkg, listener));
     }
 
     /**
@@ -497,15 +625,15 @@
         final String callerPkg = mContext.getOpPackageName();
         Log.i(TAG, "stopTethering caller:" + callerPkg);
 
-        final RequestDispatcher dispatcher = new RequestDispatcher();
-
-        dispatcher.waitForResult(listener -> {
-            try {
-                mConnector.stopTethering(type, callerPkg, listener);
-            } catch (RemoteException e) {
-                throw new IllegalStateException(e);
+        getConnector(c -> c.stopTethering(type, callerPkg, new IIntResultListener.Stub() {
+            @Override
+            public void onResult(int resultCode) {
+                // TODO: provide an API to obtain result
+                // This has never been possible as stopTethering has always been void and never
+                // taken a callback object. The only indication that callers have is if the call
+                // results in a TETHER_STATE_CHANGE broadcast.
             }
-        });
+        }));
     }
 
     /**
@@ -579,12 +707,8 @@
         final String callerPkg = mContext.getOpPackageName();
         Log.i(TAG, "getLatestTetheringEntitlementResult caller:" + callerPkg);
 
-        try {
-            mConnector.requestLatestTetheringEntitlementResult(type, receiver, showEntitlementUi,
-                    callerPkg);
-        } catch (RemoteException e) {
-            throw new IllegalStateException(e);
-        }
+        getConnector(c -> c.requestLatestTetheringEntitlementResult(
+                type, receiver, showEntitlementUi, callerPkg));
     }
 
     /**
@@ -820,11 +944,7 @@
                     });
                 }
             };
-            try {
-                mConnector.registerTetheringEventCallback(remoteCallback, callerPkg);
-            } catch (RemoteException e) {
-                throw new IllegalStateException(e);
-            }
+            getConnector(c -> c.registerTetheringEventCallback(remoteCallback, callerPkg));
             mTetheringEventCallbacks.put(callback, remoteCallback);
         }
     }
@@ -848,11 +968,8 @@
             if (remoteCallback == null) {
                 throw new IllegalArgumentException("callback was not registered.");
             }
-            try {
-                mConnector.unregisterTetheringEventCallback(remoteCallback, callerPkg);
-            } catch (RemoteException e) {
-                throw new IllegalStateException(e);
-            }
+
+            getConnector(c -> c.unregisterTetheringEventCallback(remoteCallback, callerPkg));
         }
     }
 
@@ -990,9 +1107,9 @@
         final String callerPkg = mContext.getOpPackageName();
 
         final RequestDispatcher dispatcher = new RequestDispatcher();
-        final int ret = dispatcher.waitForResult(listener -> {
+        final int ret = dispatcher.waitForResult((connector, listener) -> {
             try {
-                mConnector.isTetheringSupported(callerPkg, listener);
+                connector.isTetheringSupported(callerPkg, listener);
             } catch (RemoteException e) {
                 throw new IllegalStateException(e);
             }
@@ -1015,13 +1132,14 @@
         final String callerPkg = mContext.getOpPackageName();
         Log.i(TAG, "stopAllTethering caller:" + callerPkg);
 
-        final RequestDispatcher dispatcher = new RequestDispatcher();
-        dispatcher.waitForResult(listener -> {
-            try {
-                mConnector.stopAllTethering(callerPkg, listener);
-            } catch (RemoteException e) {
-                throw new IllegalStateException(e);
+        getConnector(c -> c.stopAllTethering(callerPkg, new IIntResultListener.Stub() {
+            @Override
+            public void onResult(int resultCode) {
+                // TODO: add an API parameter to send result to caller.
+                // This has never been possible as stopAllTethering has always been void and never
+                // taken a callback object. The only indication that callers have is if the call
+                // results in a TETHER_STATE_CHANGE broadcast.
             }
-        });
+        }));
     }
 }
diff --git a/Tethering/res/values/config.xml b/Tethering/res/values/config.xml
index 6fa1f77..379cd18 100644
--- a/Tethering/res/values/config.xml
+++ b/Tethering/res/values/config.xml
@@ -29,6 +29,12 @@
     </string-array>
 
     <!-- List of regexpressions describing the interface (if any) that represent tetherable
+         NCM interfaces.  If the device doesn't want to support tethering over NCM this should
+         be empty. -->
+    <string-array translatable="false" name="config_tether_ncm_regexs">
+    </string-array>
+
+    <!-- List of regexpressions describing the interface (if any) that represent tetherable
          Wifi interfaces.  If the device doesn't want to support tethering over Wifi this
          should be empty.  An example would be "softap.*" -->
     <string-array translatable="false" name="config_tether_wifi_regexs">
diff --git a/Tethering/res/values/overlayable.xml b/Tethering/res/values/overlayable.xml
index e089d9d..fe025c7 100644
--- a/Tethering/res/values/overlayable.xml
+++ b/Tethering/res/values/overlayable.xml
@@ -17,6 +17,7 @@
     <overlayable name="TetheringConfig">
         <policy type="product|system|vendor">
             <item type="array" name="config_tether_usb_regexs"/>
+            <item type="array" name="config_tether_ncm_regexs" />
             <item type="array" name="config_tether_wifi_regexs"/>
             <item type="array" name="config_tether_wifi_p2p_regexs"/>
             <item type="array" name="config_tether_bluetooth_regexs"/>
diff --git a/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java b/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java
index 7c41377..9fda125 100644
--- a/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java
+++ b/Tethering/src/android/net/dhcp/DhcpServerCallbacks.java
@@ -28,4 +28,9 @@
     public int getInterfaceVersion() {
         return IDhcpServerCallbacks.VERSION;
     }
+
+    @Override
+    public String getInterfaceHash() {
+        return IDhcpServerCallbacks.HASH;
+    }
 }
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 0491ad7..f39e7af 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -93,6 +93,8 @@
     private static final int WIFI_HOST_IFACE_PREFIX_LENGTH = 24;
     private static final String WIFI_P2P_IFACE_ADDR = "192.168.49.1";
     private static final int WIFI_P2P_IFACE_PREFIX_LENGTH = 24;
+    private static final String ETHERNET_IFACE_ADDR = "192.168.50.1";
+    private static final int ETHERNET_IFACE_PREFIX_LENGTH = 24;
 
     // TODO: have PanService use some visible version of this constant
     private static final String BLUETOOTH_IFACE_ADDR = "192.168.44.1";
@@ -299,6 +301,11 @@
         public int getInterfaceVersion() {
             return this.VERSION;
         }
+
+        @Override
+        public String getInterfaceHash() {
+            return this.HASH;
+        }
     }
 
     private class DhcpServerCallbacksImpl extends DhcpServerCallbacks {
@@ -416,7 +423,8 @@
         final Inet4Address srvAddr;
         int prefixLen = 0;
         try {
-            if (mInterfaceType == TetheringManager.TETHERING_USB) {
+            if (mInterfaceType == TetheringManager.TETHERING_USB
+                    || mInterfaceType == TetheringManager.TETHERING_NCM) {
                 srvAddr = (Inet4Address) parseNumericAddress(USB_NEAR_IFACE_ADDR);
                 prefixLen = USB_PREFIX_LENGTH;
             } else if (mInterfaceType == TetheringManager.TETHERING_WIFI) {
@@ -425,6 +433,10 @@
             } else if (mInterfaceType == TetheringManager.TETHERING_WIFI_P2P) {
                 srvAddr = (Inet4Address) parseNumericAddress(WIFI_P2P_IFACE_ADDR);
                 prefixLen = WIFI_P2P_IFACE_PREFIX_LENGTH;
+            } else if (mInterfaceType == TetheringManager.TETHERING_ETHERNET) {
+                // TODO: randomize address for tethering too, similarly to wifi
+                srvAddr = (Inet4Address) parseNumericAddress(ETHERNET_IFACE_ADDR);
+                prefixLen = ETHERNET_IFACE_PREFIX_LENGTH;
             } else {
                 // BT configures the interface elsewhere: only start DHCP.
                 // TODO: make all tethering types behave the same way, and delete the bluetooth
diff --git a/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java b/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java
index 3218c0b..b1ffdb0 100644
--- a/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java
+++ b/Tethering/src/android/net/util/BaseNetdUnsolicitedEventListener.java
@@ -67,4 +67,9 @@
     public int getInterfaceVersion() {
         return INetdUnsolicitedEventListener.VERSION;
     }
+
+    @Override
+    public String getInterfaceHash() {
+        return INetdUnsolicitedEventListener.HASH;
+    }
 }
diff --git a/Tethering/src/com/android/server/connectivity/tethering/Tethering.java b/Tethering/src/com/android/server/connectivity/tethering/Tethering.java
index ce6a43f..5b35bb6 100644
--- a/Tethering/src/com/android/server/connectivity/tethering/Tethering.java
+++ b/Tethering/src/com/android/server/connectivity/tethering/Tethering.java
@@ -19,6 +19,7 @@
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.hardware.usb.UsbManager.USB_CONFIGURED;
 import static android.hardware.usb.UsbManager.USB_CONNECTED;
+import static android.hardware.usb.UsbManager.USB_FUNCTION_NCM;
 import static android.hardware.usb.UsbManager.USB_FUNCTION_RNDIS;
 import static android.net.ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
@@ -29,7 +30,9 @@
 import static android.net.TetheringManager.EXTRA_AVAILABLE_TETHER;
 import static android.net.TetheringManager.EXTRA_ERRORED_TETHER;
 import static android.net.TetheringManager.TETHERING_BLUETOOTH;
+import static android.net.TetheringManager.TETHERING_ETHERNET;
 import static android.net.TetheringManager.TETHERING_INVALID;
+import static android.net.TetheringManager.TETHERING_NCM;
 import static android.net.TetheringManager.TETHERING_USB;
 import static android.net.TetheringManager.TETHERING_WIFI;
 import static android.net.TetheringManager.TETHERING_WIFI_P2P;
@@ -66,6 +69,7 @@
 import android.content.res.Resources;
 import android.hardware.usb.UsbManager;
 import android.net.ConnectivityManager;
+import android.net.EthernetManager;
 import android.net.IIntResultListener;
 import android.net.INetd;
 import android.net.ITetheringEventCallback;
@@ -110,6 +114,7 @@
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.IndentingPrintWriter;
 import com.android.internal.util.MessageUtils;
@@ -212,6 +217,13 @@
     private boolean mDataSaverEnabled = false;
     private String mWifiP2pTetherInterface = null;
 
+    @GuardedBy("mPublicSync")
+    private EthernetManager.TetheredInterfaceRequest mEthernetIfaceRequest;
+    @GuardedBy("mPublicSync")
+    private String mConfiguredEthernetIface;
+    @GuardedBy("mPublicSync")
+    private EthernetCallback mEthernetCallback;
+
     public Tethering(TetheringDependencies deps) {
         mLog.mark("Tethering.constructed");
         mDeps = deps;
@@ -408,6 +420,8 @@
             return TETHERING_USB;
         } else if (cfg.isBluetooth(iface)) {
             return TETHERING_BLUETOOTH;
+        } else if (cfg.isNcm(iface)) {
+            return TETHERING_NCM;
         }
         return TETHERING_INVALID;
     }
@@ -456,6 +470,14 @@
             case TETHERING_BLUETOOTH:
                 setBluetoothTethering(enable, listener);
                 break;
+            case TETHERING_NCM:
+                result = setNcmTethering(enable);
+                sendTetherResult(listener, result);
+                break;
+            case TETHERING_ETHERNET:
+                result = setEthernetTethering(enable);
+                sendTetherResult(listener, result);
+                break;
             default:
                 Log.w(TAG, "Invalid tether type.");
                 sendTetherResult(listener, TETHER_ERROR_UNKNOWN_IFACE);
@@ -532,6 +554,57 @@
         }, BluetoothProfile.PAN);
     }
 
+    private int setEthernetTethering(final boolean enable) {
+        final EthernetManager em = (EthernetManager) mContext.getSystemService(
+                Context.ETHERNET_SERVICE);
+        synchronized (mPublicSync) {
+            if (enable) {
+                mEthernetCallback = new EthernetCallback();
+                mEthernetIfaceRequest = em.requestTetheredInterface(mEthernetCallback);
+            } else {
+                if (mConfiguredEthernetIface != null) {
+                    stopEthernetTetheringLocked();
+                    mEthernetIfaceRequest.release();
+                }
+                mEthernetCallback = null;
+            }
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
+    private void stopEthernetTetheringLocked() {
+        if (mConfiguredEthernetIface == null) return;
+        changeInterfaceState(mConfiguredEthernetIface, IpServer.STATE_AVAILABLE);
+        stopTrackingInterfaceLocked(mConfiguredEthernetIface);
+        mConfiguredEthernetIface = null;
+    }
+
+    private class EthernetCallback implements EthernetManager.TetheredInterfaceCallback {
+        @Override
+        public void onAvailable(String iface) {
+            synchronized (mPublicSync) {
+                if (this != mEthernetCallback) {
+                    // Ethernet callback arrived after Ethernet tethering stopped. Ignore.
+                    return;
+                }
+                maybeTrackNewInterfaceLocked(iface, TETHERING_ETHERNET);
+                changeInterfaceState(iface, IpServer.STATE_TETHERED);
+                mConfiguredEthernetIface = iface;
+            }
+        }
+
+        @Override
+        public void onUnavailable() {
+            synchronized (mPublicSync) {
+                if (this != mEthernetCallback) {
+                    // onAvailable called after stopping Ethernet tethering.
+                    return;
+                }
+                stopEthernetTetheringLocked();
+            }
+        }
+    }
+
     int tether(String iface) {
         return tether(iface, IpServer.STATE_TETHERED);
     }
@@ -582,6 +655,7 @@
         stopTethering(TETHERING_WIFI_P2P);
         stopTethering(TETHERING_USB);
         stopTethering(TETHERING_BLUETOOTH);
+        stopTethering(TETHERING_ETHERNET);
     }
 
     int getLastTetherError(String iface) {
@@ -805,6 +879,7 @@
             final boolean usbConnected = intent.getBooleanExtra(USB_CONNECTED, false);
             final boolean usbConfigured = intent.getBooleanExtra(USB_CONFIGURED, false);
             final boolean rndisEnabled = intent.getBooleanExtra(USB_FUNCTION_RNDIS, false);
+            final boolean ncmEnabled = intent.getBooleanExtra(USB_FUNCTION_NCM, false);
 
             mLog.log(String.format("USB bcast connected:%s configured:%s rndis:%s",
                     usbConnected, usbConfigured, rndisEnabled));
@@ -832,6 +907,8 @@
                 } else if (usbConfigured && rndisEnabled) {
                     // Tether if rndis is enabled and usb is configured.
                     tetherMatchingInterfaces(IpServer.STATE_TETHERED, TETHERING_USB);
+                } else if (usbConnected && ncmEnabled) {
+                    tetherMatchingInterfaces(IpServer.STATE_LOCAL_ONLY, TETHERING_NCM);
                 }
                 mRndisEnabled = usbConfigured && rndisEnabled;
             }
@@ -1133,6 +1210,16 @@
         return TETHER_ERROR_NO_ERROR;
     }
 
+    private int setNcmTethering(boolean enable) {
+        if (VDBG) Log.d(TAG, "setNcmTethering(" + enable + ")");
+        UsbManager usbManager = (UsbManager) mContext.getSystemService(Context.USB_SERVICE);
+        synchronized (mPublicSync) {
+            usbManager.setCurrentFunctions(enable ? UsbManager.FUNCTION_NCM
+                    : UsbManager.FUNCTION_NONE);
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
     // TODO review API - figure out how to delete these entirely.
     String[] getTetheredIfaces() {
         ArrayList<String> list = new ArrayList<String>();
diff --git a/Tethering/src/com/android/server/connectivity/tethering/TetheringConfiguration.java b/Tethering/src/com/android/server/connectivity/tethering/TetheringConfiguration.java
index 068c346..7e9e26f 100644
--- a/Tethering/src/com/android/server/connectivity/tethering/TetheringConfiguration.java
+++ b/Tethering/src/com/android/server/connectivity/tethering/TetheringConfiguration.java
@@ -83,6 +83,7 @@
     public final String[] tetherableWifiRegexs;
     public final String[] tetherableWifiP2pRegexs;
     public final String[] tetherableBluetoothRegexs;
+    public final String[] tetherableNcmRegexs;
     public final boolean isDunRequired;
     public final boolean chooseUpstreamAutomatically;
     public final Collection<Integer> preferredUpstreamIfaceTypes;
@@ -103,6 +104,7 @@
         Resources res = getResources(ctx, activeDataSubId);
 
         tetherableUsbRegexs = getResourceStringArray(res, R.array.config_tether_usb_regexs);
+        tetherableNcmRegexs = getResourceStringArray(res, R.array.config_tether_ncm_regexs);
         // TODO: Evaluate deleting this altogether now that Wi-Fi always passes
         // us an interface name. Careful consideration needs to be given to
         // implications for Settings and for provisioning checks.
@@ -156,6 +158,11 @@
         return matchesDownstreamRegexs(iface, tetherableBluetoothRegexs);
     }
 
+    /** Check if interface is ncm */
+    public boolean isNcm(String iface) {
+        return matchesDownstreamRegexs(iface, tetherableNcmRegexs);
+    }
+
     /** Check whether no ui entitlement application is available.*/
     public boolean hasMobileHotspotProvisionApp() {
         return !TextUtils.isEmpty(provisioningAppNoUi);
@@ -170,6 +177,7 @@
         dumpStringArray(pw, "tetherableWifiRegexs", tetherableWifiRegexs);
         dumpStringArray(pw, "tetherableWifiP2pRegexs", tetherableWifiP2pRegexs);
         dumpStringArray(pw, "tetherableBluetoothRegexs", tetherableBluetoothRegexs);
+        dumpStringArray(pw, "tetherableNcmRegexs", tetherableNcmRegexs);
 
         pw.print("isDunRequired: ");
         pw.println(isDunRequired);
diff --git a/Tethering/tests/unit/Android.bp b/Tethering/tests/unit/Android.bp
index 53782fe..13174c5 100644
--- a/Tethering/tests/unit/Android.bp
+++ b/Tethering/tests/unit/Android.bp
@@ -19,6 +19,7 @@
     certificate: "platform",
     srcs: [
         "src/**/*.java",
+        "src/**/*.kt",
     ],
     test_suites: [
         "device-tests",
diff --git a/Tethering/tests/unit/AndroidManifest.xml b/Tethering/tests/unit/AndroidManifest.xml
index 0a1cdd3..530bc07 100644
--- a/Tethering/tests/unit/AndroidManifest.xml
+++ b/Tethering/tests/unit/AndroidManifest.xml
@@ -16,6 +16,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="com.android.networkstack.tethering.tests.unit">
 
+    <uses-permission android:name="android.permission.TETHER_PRIVILEGED"/>
+
     <application android:debuggable="true">
         <uses-library android:name="android.test.runner" />
     </application>
diff --git a/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
index e6a5521..e7c3e55 100644
--- a/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/server/connectivity/tethering/TetheringTest.java
@@ -18,6 +18,7 @@
 
 import static android.hardware.usb.UsbManager.USB_CONFIGURED;
 import static android.hardware.usb.UsbManager.USB_CONNECTED;
+import static android.hardware.usb.UsbManager.USB_FUNCTION_NCM;
 import static android.hardware.usb.UsbManager.USB_FUNCTION_RNDIS;
 import static android.net.ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED;
 import static android.net.ConnectivityManager.RESTRICT_BACKGROUND_STATUS_DISABLED;
@@ -27,6 +28,7 @@
 import static android.net.TetheringManager.EXTRA_ACTIVE_LOCAL_ONLY;
 import static android.net.TetheringManager.EXTRA_ACTIVE_TETHER;
 import static android.net.TetheringManager.EXTRA_AVAILABLE_TETHER;
+import static android.net.TetheringManager.TETHERING_NCM;
 import static android.net.TetheringManager.TETHERING_USB;
 import static android.net.TetheringManager.TETHERING_WIFI;
 import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
@@ -151,6 +153,7 @@
     private static final String TEST_USB_IFNAME = "test_rndis0";
     private static final String TEST_WLAN_IFNAME = "test_wlan0";
     private static final String TEST_P2P_IFNAME = "test_p2p-p2p0-0";
+    private static final String TEST_NCM_IFNAME = "test_ncm0";
     private static final String TETHERING_NAME = "Tethering";
 
     private static final int DHCPSERVER_START_TIMEOUT_MS = 1000;
@@ -252,9 +255,11 @@
                     ifName.equals(TEST_USB_IFNAME)
                             || ifName.equals(TEST_WLAN_IFNAME)
                             || ifName.equals(TEST_MOBILE_IFNAME)
-                            || ifName.equals(TEST_P2P_IFNAME));
+                            || ifName.equals(TEST_P2P_IFNAME)
+                            || ifName.equals(TEST_NCM_IFNAME));
             final String[] ifaces = new String[] {
-                    TEST_USB_IFNAME, TEST_WLAN_IFNAME, TEST_MOBILE_IFNAME, TEST_P2P_IFNAME};
+                    TEST_USB_IFNAME, TEST_WLAN_IFNAME, TEST_MOBILE_IFNAME, TEST_P2P_IFNAME,
+                    TEST_NCM_IFNAME};
             return new InterfaceParams(ifName, ArrayUtils.indexOf(ifaces, ifName) + IFINDEX_OFFSET,
                     MacAddress.ALL_ZEROS_ADDRESS);
         }
@@ -428,13 +433,16 @@
                 .thenReturn(new String[]{ "test_p2p-p2p\\d-.*" });
         when(mResources.getStringArray(R.array.config_tether_bluetooth_regexs))
                 .thenReturn(new String[0]);
+        when(mResources.getStringArray(R.array.config_tether_ncm_regexs))
+                .thenReturn(new String[] { "test_ncm\\d" });
         when(mResources.getIntArray(R.array.config_tether_upstream_types)).thenReturn(new int[0]);
         when(mResources.getBoolean(R.bool.config_tether_upstream_automatic)).thenReturn(false);
         when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
                 false);
         when(mNetd.interfaceGetList())
                 .thenReturn(new String[] {
-                        TEST_MOBILE_IFNAME, TEST_WLAN_IFNAME, TEST_USB_IFNAME, TEST_P2P_IFNAME});
+                        TEST_MOBILE_IFNAME, TEST_WLAN_IFNAME, TEST_USB_IFNAME, TEST_P2P_IFNAME,
+                        TEST_NCM_IFNAME});
         when(mResources.getString(R.string.config_wifi_tether_enable)).thenReturn("");
         mInterfaceConfiguration = new InterfaceConfigurationParcel();
         mInterfaceConfiguration.flags = new String[0];
@@ -524,11 +532,16 @@
                 P2P_RECEIVER_PERMISSIONS_FOR_BROADCAST);
     }
 
-    private void sendUsbBroadcast(boolean connected, boolean configured, boolean rndisFunction) {
+    private void sendUsbBroadcast(boolean connected, boolean configured, boolean function,
+            int type) {
         final Intent intent = new Intent(UsbManager.ACTION_USB_STATE);
         intent.putExtra(USB_CONNECTED, connected);
         intent.putExtra(USB_CONFIGURED, configured);
-        intent.putExtra(USB_FUNCTION_RNDIS, rndisFunction);
+        if (type == TETHERING_USB) {
+            intent.putExtra(USB_FUNCTION_RNDIS, function);
+        } else {
+            intent.putExtra(USB_FUNCTION_NCM, function);
+        }
         mServiceContext.sendStickyBroadcastAsUser(intent, UserHandle.ALL);
     }
 
@@ -578,6 +591,15 @@
         verifyNoMoreInteractions(mWifiManager);
     }
 
+    private void prepareNcmTethering() {
+        // Emulate startTethering(TETHERING_NCM) called
+        mTethering.startTethering(createTetheringRquestParcel(TETHERING_NCM), null);
+        mLooper.dispatchAll();
+        verify(mUsbManager, times(1)).setCurrentFunctions(UsbManager.FUNCTION_NCM);
+
+        mTethering.interfaceStatusChanged(TEST_NCM_IFNAME, true);
+    }
+
     private void prepareUsbTethering(UpstreamNetworkState upstreamState) {
         when(mUpstreamNetworkMonitor.getCurrentPreferredUpstream()).thenReturn(upstreamState);
         when(mUpstreamNetworkMonitor.selectPreferredUpstreamType(any()))
@@ -600,7 +622,7 @@
         verifyNoMoreInteractions(mNetd);
 
         // Pretend we then receive USB configured broadcast.
-        sendUsbBroadcast(true, true, true);
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
         mLooper.dispatchAll();
         // Now we should see the start of tethering mechanics (in this case:
         // tetherMatchingInterfaces() which starts by fetching all interfaces).
@@ -691,7 +713,7 @@
 
     private void runUsbTethering(UpstreamNetworkState upstreamState) {
         prepareUsbTethering(upstreamState);
-        sendUsbBroadcast(true, true, true);
+        sendUsbBroadcast(true, true, true, TETHERING_USB);
         mLooper.dispatchAll();
     }
 
@@ -814,6 +836,29 @@
         verify(mUpstreamNetworkMonitor, times(1)).setCurrentUpstream(upstreamState.network);
     }
 
+    private void runNcmTethering() {
+        prepareNcmTethering();
+        sendUsbBroadcast(true, true, true, TETHERING_NCM);
+        mLooper.dispatchAll();
+    }
+
+    @Test
+    public void workingNcmTethering() throws Exception {
+        runNcmTethering();
+
+        verify(mDhcpServer, timeout(DHCPSERVER_START_TIMEOUT_MS).times(1)).start(any());
+    }
+
+    @Test
+    public void workingNcmTethering_LegacyDhcp() {
+        when(mResources.getBoolean(R.bool.config_tether_enable_legacy_dhcp_server)).thenReturn(
+                true);
+        sendConfigurationChanged();
+        runNcmTethering();
+
+        verify(mIpServerDependencies, never()).makeDhcpServer(any(), any(), any());
+    }
+
     @Test
     public void workingLocalOnlyHotspotEnrichedApBroadcastWithIfaceChanged() throws Exception {
         workingLocalOnlyHotspotEnrichedApBroadcast(true);