Merge "Creating interface name to index tracking for Bpf Maps." into main
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
index 2f9c3bc..0a66f01 100644
--- a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
@@ -37,7 +37,6 @@
 import android.os.Process;
 import android.os.RemoteException;
 import android.os.ResultReceiver;
-import android.text.TextUtils;
 import android.util.ArrayMap;
 import android.util.ArraySet;
 import android.util.Log;
@@ -1259,44 +1258,6 @@
             return sj.toString();
         }
 
-        @SuppressLint("UnflaggedApi")
-        private static boolean supportsInterfaceName(int tetheringType) {
-            // TODO: Check the interface name for TETHERING_WIFI and TETHERING_WIFI_P2P once
-            //       they're actually used.
-            // Suppress lint for TETHERING_VIRTUAL since this method is only used internally.
-            return tetheringType == TETHERING_VIRTUAL;
-        }
-
-        private static boolean supportsConcurrentConnectivityScopes(int tetheringType) {
-            // Currently, only WIFI supports simultaneous local and global connectivity.
-            // This can't happen for REQUEST_TYPE_EXPLICIT requests, because
-            // TetheringRequest.Builder will not allow building an explicit TetheringRequest
-            // with TETHERING_WIFI and CONNECTIVITY_SCOPE_LOCAL, but when local-only hotspot
-            // is running, there is a REQUEST_TYPE_IMPLICIT request in the serving request list.
-            return tetheringType == TETHERING_WIFI;
-        }
-
-        /**
-         * Returns true if the other TetheringRequest "fuzzy" matches this one. This is used
-         * internally to match tracked requests with external requests from API calls, and to reject
-         * additional requests that the link layer has no capacity for.
-         * @hide
-         */
-        public boolean fuzzyMatches(final TetheringRequest other) {
-            if (other == null) return false;
-            final int type = getTetheringType();
-            if (type != other.getTetheringType()) return false;
-            if (supportsInterfaceName(type)
-                    && !TextUtils.equals(getInterfaceName(), other.getInterfaceName())) {
-                return false;
-            }
-            if (supportsConcurrentConnectivityScopes(type)
-                    && getConnectivityScope() != other.getConnectivityScope()) {
-                return false;
-            }
-            return true;
-        }
-
         /**
          * @hide
          */
@@ -1318,8 +1279,6 @@
         public boolean equalsIgnoreUidPackage(TetheringRequest otherRequest) {
             TetheringRequestParcel parcel = getParcel();
             TetheringRequestParcel otherParcel = otherRequest.getParcel();
-            // Note: Changes here should also be reflected in fuzzyMatches(TetheringRequest) when
-            //       appropriate.
             return parcel.requestType == otherParcel.requestType
                     && parcel.tetheringType == otherParcel.tetheringType
                     && Objects.equals(parcel.localIPv4Address, otherParcel.localIPv4Address)
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 70a3442..d0ba431 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -415,6 +415,12 @@
         return mIpv4PrefixRequest;
     }
 
+    /** The TetheringRequest the IpServer started with. */
+    @Nullable
+    public TetheringRequest getTetheringRequest() {
+        return mTetheringRequest;
+    }
+
     /**
      * Get the latest list of DHCP leases that was reported. Must be called on the IpServer looper
      * thread.
diff --git a/Tethering/src/com/android/networkstack/tethering/RequestTracker.java b/Tethering/src/com/android/networkstack/tethering/RequestTracker.java
index 9c61716..3ebe4f7 100644
--- a/Tethering/src/com/android/networkstack/tethering/RequestTracker.java
+++ b/Tethering/src/com/android/networkstack/tethering/RequestTracker.java
@@ -19,8 +19,6 @@
 import static com.android.networkstack.tethering.util.TetheringUtils.createPlaceholderRequest;
 
 import android.net.TetheringManager.TetheringRequest;
-import android.net.ip.IpServer;
-import android.util.ArrayMap;
 import android.util.Log;
 
 import androidx.annotation.NonNull;
@@ -30,7 +28,6 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
 
 /**
  * Helper class to keep track of tethering requests.
@@ -39,17 +36,29 @@
  *    layer to start.
  * 2) When the link layer is up, use {@link #getOrCreatePendingRequest(int)} to get a request to
  *    start IP serving with.
- * 3) Remove pending request with {@link #removePendingRequest(TetheringRequest)}.
+ * 3) Remove all pending requests with {@link #removeAllPendingRequests(int)}.
  * Note: This class is not thread-safe.
+ * TODO: Add the pending IIntResultListeners at the same time as the pending requests, and
+ *       call them when we get the tether result.
+ * TODO: Add support for multiple Bluetooth requests before the PAN service connects instead of
+ *       using a separate mPendingPanRequestListeners.
+ * TODO: Add support for fuzzy-matched requests.
  */
 public class RequestTracker {
     private static final String TAG = RequestTracker.class.getSimpleName();
 
-    @NonNull
-    private final boolean mUseFuzzyMatching;
+    private class PendingRequest {
+        @NonNull
+        private final TetheringRequest mTetheringRequest;
 
-    public RequestTracker(boolean useFuzzyMatching) {
-        mUseFuzzyMatching = useFuzzyMatching;
+        private PendingRequest(@NonNull TetheringRequest tetheringRequest) {
+            mTetheringRequest = tetheringRequest;
+        }
+
+        @NonNull
+        TetheringRequest getTetheringRequest() {
+            return mTetheringRequest;
+        }
     }
 
     public enum AddResult {
@@ -60,51 +69,24 @@
         /**
          * Failure indicating that the request could not be added due to a request of the same type
          * with conflicting parameters already pending. If so, we must stop tethering for the
-         * pending request before trying to add the result again. Only returned on V-.
+         * pending request before trying to add the result again.
          */
-        FAILURE_DUPLICATE_REQUEST_RESTART,
-        /**
-         * Failure indicating that the request could not be added due to a fuzzy-matched request
-         * already pending or serving. Only returned on B+.
-         */
-        FAILURE_DUPLICATE_REQUEST_ERROR,
+        FAILURE_CONFLICTING_PENDING_REQUEST
     }
 
     /**
-     * List of pending requests added by {@link #addPendingRequest(TetheringRequest)}
-     * There can be only one per type, since we remove every request of the
-     * same type when we add a request.
+     * List of pending requests added by {@link #addPendingRequest(TetheringRequest)}. There can be
+     * only one per type, since we remove every request of the same type when we add a request.
      */
-    private final List<TetheringRequest> mPendingRequests = new ArrayList<>();
-    /**
-     * List of serving requests added by
-     * {@link #promoteRequestToServing(IpServer, TetheringRequest)}.
-     */
-    private final Map<IpServer, TetheringRequest> mServingRequests = new ArrayMap<>();
+    private final List<PendingRequest> mPendingRequests = new ArrayList<>();
 
     @VisibleForTesting
     List<TetheringRequest> getPendingTetheringRequests() {
-        return new ArrayList<>(mPendingRequests);
-    }
-
-    /**
-     * Adds a pending request or fails with FAILURE_CONFLICTING_REQUEST_FAIL if the request
-     * fuzzy-matches an existing request (either pending or serving).
-     */
-    public AddResult addPendingRequestFuzzyMatched(@NonNull final TetheringRequest newRequest) {
-        List<TetheringRequest> existingRequests = new ArrayList<>();
-        existingRequests.addAll(mServingRequests.values());
-        existingRequests.addAll(mPendingRequests);
-        for (TetheringRequest request : existingRequests) {
-            if (request.fuzzyMatches(newRequest)) {
-                Log.i(TAG, "Cannot add pending request due to existing fuzzy-matched "
-                        + "request: " + request);
-                return AddResult.FAILURE_DUPLICATE_REQUEST_ERROR;
-            }
+        List<TetheringRequest> requests = new ArrayList<>();
+        for (PendingRequest pendingRequest : mPendingRequests) {
+            requests.add(pendingRequest.getTetheringRequest());
         }
-
-        mPendingRequests.add(newRequest);
-        return AddResult.SUCCESS;
+        return requests;
     }
 
     /**
@@ -113,12 +95,9 @@
      * layer comes up. The result of the add operation will be returned as an AddResult code.
      */
     public AddResult addPendingRequest(@NonNull final TetheringRequest newRequest) {
-        if (mUseFuzzyMatching) {
-            return addPendingRequestFuzzyMatched(newRequest);
-        }
-
         // Check the existing requests to see if it is OK to add the new request.
-        for (TetheringRequest existingRequest : mPendingRequests) {
+        for (PendingRequest request : mPendingRequests) {
+            TetheringRequest existingRequest = request.getTetheringRequest();
             if (existingRequest.getTetheringType() != newRequest.getTetheringType()) {
                 continue;
             }
@@ -126,7 +105,7 @@
             // Can't add request if there's a request of the same type with different
             // parameters.
             if (!existingRequest.equalsIgnoreUidPackage(newRequest)) {
-                return AddResult.FAILURE_DUPLICATE_REQUEST_RESTART;
+                return AddResult.FAILURE_CONFLICTING_PENDING_REQUEST;
             }
         }
 
@@ -134,7 +113,7 @@
         // conflicting parameters above, so these would have been equivalent anyway (except for
         // UID).
         removeAllPendingRequests(newRequest.getTetheringType());
-        mPendingRequests.add(newRequest);
+        mPendingRequests.add(new PendingRequest(newRequest));
         return AddResult.SUCCESS;
     }
 
@@ -166,8 +145,10 @@
      */
     @Nullable
     public TetheringRequest getNextPendingRequest(int type) {
-        for (TetheringRequest request : mPendingRequests) {
-            if (request.getTetheringType() == type) return request;
+        for (PendingRequest pendingRequest : mPendingRequests) {
+            TetheringRequest tetheringRequest =
+                    pendingRequest.getTetheringRequest();
+            if (tetheringRequest.getTetheringType() == type) return tetheringRequest;
         }
         return null;
     }
@@ -177,83 +158,7 @@
      *
      * @param type Tethering type
      */
-    public void removeAllPendingRequests(final int type) {
-        mPendingRequests.removeIf(r -> r.getTetheringType() == type);
-    }
-
-    /**
-     * Removes a specific pending request.
-     *
-     * Note: For V-, this will be the same as removeAllPendingRequests to align with historical
-     * behavior.
-     *
-     * @param request Request to be removed
-     */
-    public void removePendingRequest(@NonNull TetheringRequest request) {
-        if (!mUseFuzzyMatching) {
-            // Remove all requests of the same type to match the historical behavior.
-            removeAllPendingRequests(request.getTetheringType());
-            return;
-        }
-
-        mPendingRequests.removeIf(r -> r.equals(request));
-    }
-
-    /**
-     * Removes a tethering request from the pending list and promotes it to serving with the
-     * IpServer that is using it.
-     * Note: If mUseFuzzyMatching is false, then the request will be removed from the pending list,
-     * but it will not be added to serving list.
-     */
-    public void promoteRequestToServing(@NonNull final IpServer ipServer,
-            @NonNull final TetheringRequest tetheringRequest) {
-        removePendingRequest(tetheringRequest);
-        if (!mUseFuzzyMatching) return;
-        mServingRequests.put(ipServer, tetheringRequest);
-    }
-
-
-    /**
-     * Returns the serving request tied to the given IpServer, or null if there is none.
-     * Note: If mUseFuzzyMatching is false, then this will always return null.
-     */
-    @Nullable
-    public TetheringRequest getServingRequest(@NonNull final IpServer ipServer) {
-        return mServingRequests.get(ipServer);
-    }
-
-    /**
-     * Removes the serving request tied to the given IpServer.
-     * Note: If mUseFuzzyMatching is false, then this is a no-op since serving requests are unused
-     * for that configuration.
-     */
-    public void removeServingRequest(@NonNull final IpServer ipServer) {
-        mServingRequests.remove(ipServer);
-    }
-
-    /**
-     * Removes all serving requests of the given tethering type.
-     *
-     * @param type Tethering type
-     */
-    public void removeAllServingRequests(final int type) {
-        mServingRequests.entrySet().removeIf(e -> e.getValue().getTetheringType() == type);
-    }
-
-    /**
-     * Returns an existing (pending or serving) request that fuzzy matches the given request.
-     * Optionally specify matchUid to only return requests with the same uid.
-     */
-    public TetheringRequest findFuzzyMatchedRequest(
-            @NonNull final TetheringRequest tetheringRequest, boolean matchUid) {
-        List<TetheringRequest> allRequests = new ArrayList<>();
-        allRequests.addAll(getPendingTetheringRequests());
-        allRequests.addAll(mServingRequests.values());
-        for (TetheringRequest request : allRequests) {
-            if (!request.fuzzyMatches(tetheringRequest)) continue;
-            if (matchUid && tetheringRequest.getUid() != request.getUid()) continue;
-            return request;
-        }
-        return null;
+    public void removeAllPendingRequests(int type) {
+        mPendingRequests.removeIf(r -> r.getTetheringRequest().getTetheringType() == type);
     }
 }
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 59f05ed..1a26658 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -43,7 +43,6 @@
 import static android.net.TetheringManager.TETHERING_WIFI_P2P;
 import static android.net.TetheringManager.TETHERING_WIGIG;
 import static android.net.TetheringManager.TETHER_ERROR_BLUETOOTH_SERVICE_PENDING;
-import static android.net.TetheringManager.TETHER_ERROR_DUPLICATE_REQUEST;
 import static android.net.TetheringManager.TETHER_ERROR_INTERNAL_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_SERVICE_UNAVAIL;
@@ -68,8 +67,6 @@
 import static android.telephony.CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED;
 import static android.telephony.SubscriptionManager.INVALID_SUBSCRIPTION_ID;
 
-import static com.android.networkstack.tethering.RequestTracker.AddResult.FAILURE_DUPLICATE_REQUEST_ERROR;
-import static com.android.networkstack.tethering.RequestTracker.AddResult.FAILURE_DUPLICATE_REQUEST_RESTART;
 import static com.android.networkstack.tethering.TetheringConfiguration.TETHER_FORCE_USB_FUNCTIONS;
 import static com.android.networkstack.tethering.TetheringNotificationUpdater.DOWNSTREAM_NONE;
 import static com.android.networkstack.tethering.UpstreamNetworkMonitor.isCellular;
@@ -312,7 +309,7 @@
         mLooper = mDeps.makeTetheringLooper();
         mNotificationUpdater = mDeps.makeNotificationUpdater(mContext, mLooper);
         mTetheringMetrics = mDeps.makeTetheringMetrics(mContext);
-        mRequestTracker = new RequestTracker(isTetheringWithSoftApConfigEnabled());
+        mRequestTracker = new RequestTracker();
 
         mTetherStates = new ArrayMap<>();
         mConnectedClientsTracker = new ConnectedClientsTracker();
@@ -463,7 +460,6 @@
         return mSettingsObserver;
     }
 
-    // TODO: Replace with SdkLevel.isAtLeastB() once the feature is fully implemented.
     boolean isTetheringWithSoftApConfigEnabled() {
         return SdkLevel.isAtLeastB() && Flags.tetheringWithSoftApConfig();
     }
@@ -708,16 +704,9 @@
             RequestTracker.AddResult result = mRequestTracker.addPendingRequest(request);
             // If tethering is already pending with a conflicting request, stop tethering before
             // starting.
-            if (result == FAILURE_DUPLICATE_REQUEST_RESTART) {
+            if (result == RequestTracker.AddResult.FAILURE_CONFLICTING_PENDING_REQUEST) {
                 stopTetheringInternal(type); // Also removes the request from the tracker.
                 mRequestTracker.addPendingRequest(request);
-            } else if (result == FAILURE_DUPLICATE_REQUEST_ERROR) {
-                // Reject any fuzzy matched request.
-                // TODO: Add a CTS test to verify back-to-back start/stop calls succeed. This must
-                // be for a non-Wifi type, since Wifi will reject the start calls if it hasn't
-                // brought down the SoftAP yet.
-                sendTetherResult(listener, TETHER_ERROR_DUPLICATE_REQUEST);
-                return;
             }
 
             if (request.isExemptFromEntitlementCheck()) {
@@ -737,28 +726,39 @@
         });
     }
 
+    private boolean isTetheringTypePendingOrServing(final int type) {
+        if (mRequestTracker.getNextPendingRequest(type) != null) return true;
+        for (TetherState state : mTetherStates.values()) {
+            // TODO: isCurrentlyServing only starts returning true once the IpServer has processed
+            // the CMD_TETHER_REQUESTED. Ensure that we consider the request to be serving even when
+            // that has not happened yet.
+            if (state.isCurrentlyServing() && state.ipServer.interfaceType() == type) return true;
+        }
+        return false;
+    }
+
     void stopTetheringRequest(@NonNull final TetheringRequest request,
             @NonNull final IIntResultListener listener) {
         if (!isTetheringWithSoftApConfigEnabled()) return;
-        final boolean hasNetworkSettings = hasCallingPermission(NETWORK_SETTINGS);
         mHandler.post(() -> {
-            if (mRequestTracker.findFuzzyMatchedRequest(request, !hasNetworkSettings) != null) {
-                final int type = request.getTetheringType();
+            final int type = request.getTetheringType();
+            if (isTetheringTypePendingOrServing(type)) {
                 stopTetheringInternal(type);
-                // TODO: We should send the success result after the waiting for tethering to
-                //       actually stop.
-                sendTetherResult(listener, TETHER_ERROR_NO_ERROR);
+                try {
+                    listener.onResult(TETHER_ERROR_NO_ERROR);
+                } catch (RemoteException ignored) { }
                 return;
             }
 
             // Request doesn't match any active requests, ignore.
-            sendTetherResult(listener, TETHER_ERROR_UNKNOWN_REQUEST);
+            try {
+                listener.onResult(TETHER_ERROR_UNKNOWN_REQUEST);
+            } catch (RemoteException ignored) { }
         });
     }
 
     void stopTetheringInternal(int type) {
         mRequestTracker.removeAllPendingRequests(type);
-        mRequestTracker.removeAllServingRequests(type);
 
         // Using a placeholder here is ok since none of the disable APIs use the request for
         // anything. We simply need the tethering type to know which link layer to poke for removal.
@@ -802,25 +802,21 @@
         // The result of Bluetooth tethering will be sent after the pan service connects.
         if (result == TETHER_ERROR_BLUETOOTH_SERVICE_PENDING) return;
 
-        sendTetherResultAndRemoveOnError(request, listener, result);
+        sendTetherResult(listener, result, type);
     }
 
-    private void sendTetherResult(final IIntResultListener listener, final int result) {
+    private void sendTetherResult(final IIntResultListener listener, final int result,
+            final int type) {
         if (listener != null) {
             try {
                 listener.onResult(result);
-            } catch (RemoteException e) {
-            }
+            } catch (RemoteException e) { }
         }
-    }
 
-    private void sendTetherResultAndRemoveOnError(TetheringRequest request,
-            final IIntResultListener listener, final int result) {
-        sendTetherResult(listener, result);
-
+        // If changing tethering fail, remove corresponding request
+        // no matter who trigger the start/stop.
         if (result != TETHER_ERROR_NO_ERROR) {
-            mRequestTracker.removePendingRequest(request);
-            final int type = request.getTetheringType();
+            mRequestTracker.removeAllPendingRequests(type);
             mTetheringMetrics.updateErrorCode(type, result);
             mTetheringMetrics.sendReport(type);
         }
@@ -866,7 +862,8 @@
             // the service just to stop tethering since tethering is not started. Just remove
             // any pending request to enable tethering, and notify them that they have failed.
             if (mPendingPanRequestListener != null) {
-                sendTetherResult(mPendingPanRequestListener, TETHER_ERROR_SERVICE_UNAVAIL);
+                sendTetherResult(mPendingPanRequestListener, TETHER_ERROR_SERVICE_UNAVAIL,
+                        TETHERING_BLUETOOTH);
             }
             mPendingPanRequestListener = null;
             return TETHER_ERROR_NO_ERROR;
@@ -907,10 +904,7 @@
                 if (mPendingPanRequestListener != null) {
                     final int result = setBluetoothTetheringSettings(mBluetoothPan,
                             true /* enable */);
-                    sendTetherResultAndRemoveOnError(
-                            mRequestTracker.getOrCreatePendingRequest(TETHERING_BLUETOOTH),
-                            mPendingPanRequestListener,
-                            result);
+                    sendTetherResult(mPendingPanRequestListener, result, TETHERING_BLUETOOTH);
                 }
                 mPendingPanRequestListener = null;
             });
@@ -924,10 +918,8 @@
                 mIsConnected = false;
 
                 if (mPendingPanRequestListener != null) {
-                    sendTetherResultAndRemoveOnError(
-                            mRequestTracker.getOrCreatePendingRequest(TETHERING_BLUETOOTH),
-                            mPendingPanRequestListener,
-                            TETHER_ERROR_SERVICE_UNAVAIL);
+                    sendTetherResult(mPendingPanRequestListener, TETHER_ERROR_SERVICE_UNAVAIL,
+                            TETHERING_BLUETOOTH);
                 }
                 mPendingPanRequestListener = null;
                 mBluetoothIfaceRequest = null;
@@ -1101,7 +1093,9 @@
         final int type = ifaceNameToType(iface);
         if (type == TETHERING_INVALID) {
             Log.e(TAG, "Ignoring call to legacy tether for unknown iface " + iface);
-            sendTetherResult(listener, TETHER_ERROR_UNKNOWN_IFACE);
+            try {
+                listener.onResult(TETHER_ERROR_UNKNOWN_IFACE);
+            } catch (RemoteException e) { }
         }
 
         TetheringRequest request = mRequestTracker.getNextPendingRequest(type);
@@ -1138,7 +1132,9 @@
                 // Do nothing
                 break;
         }
-        sendTetherResult(listener, result);
+        try {
+            listener.onResult(result);
+        } catch (RemoteException e) { }
     }
 
     /**
@@ -1171,9 +1167,11 @@
             Log.e(TAG, "Tried to Tether an unavailable iface: " + iface + ", ignoring");
             return TETHER_ERROR_UNAVAIL_IFACE;
         }
-        mRequestTracker.promoteRequestToServing(tetherState.ipServer, request);
         // NOTE: If a CMD_TETHER_REQUESTED message is already in the IpServer's queue but not yet
         // processed, this will be a no-op and it will not return an error.
+        //
+        // This code cannot race with untether() because they both run on the handler thread.
+        mRequestTracker.removeAllPendingRequests(request.getTetheringType());
         tetherState.ipServer.enable(request);
         if (request.getRequestType() == REQUEST_TYPE_PLACEHOLDER) {
             TerribleErrorLog.logTerribleError(TetheringStatsLog::write,
@@ -1193,7 +1191,10 @@
             return;
         }
         mHandler.post(() -> {
-            sendTetherResult(listener, legacyUntetherInternal(iface));
+            try {
+                listener.onResult(legacyUntetherInternal(iface));
+            } catch (RemoteException e) {
+            }
         });
     }
 
@@ -1208,7 +1209,7 @@
             Log.e(TAG, "Tried to untether an inactive iface :" + iface + ", ignoring");
             return TETHER_ERROR_UNAVAIL_IFACE;
         }
-        ensureIpServerUnwanted(tetherState.ipServer);
+        tetherState.ipServer.unwanted();
         return TETHER_ERROR_NO_ERROR;
     }
 
@@ -1288,12 +1289,7 @@
             final TetherState tetherState = mTetherStates.valueAt(i);
             final int type = tetherState.ipServer.interfaceType();
             final String iface = mTetherStates.keyAt(i);
-            // Note: serving requests are only populated on B+. B+ also uses the sync state
-            // machine by default. This ensures that the serving request is (correctly) populated
-            // after the IpServer enters the available state and before it enters the serving
-            // state.
-            final TetheringRequest request =
-                    mRequestTracker.getServingRequest(tetherState.ipServer);
+            final TetheringRequest request = tetherState.ipServer.getTetheringRequest();
             final boolean includeSoftApConfig = request != null && cookie != null
                     && (cookie.uid == request.getUid() || cookie.hasSystemPrivilege);
             final TetheringInterface tetheringIface = new TetheringInterface(type, iface,
@@ -1615,7 +1611,7 @@
 
     private void disableWifiIpServingCommon(int tetheringType, String ifname) {
         if (!TextUtils.isEmpty(ifname) && mTetherStates.containsKey(ifname)) {
-            ensureIpServerUnwanted(mTetherStates.get(ifname).ipServer);
+            mTetherStates.get(ifname).ipServer.unwanted();
             return;
         }
 
@@ -1632,7 +1628,7 @@
         for (int i = 0; i < mTetherStates.size(); i++) {
             final IpServer ipServer = mTetherStates.valueAt(i).ipServer;
             if (ipServer.interfaceType() == tetheringType) {
-                ensureIpServerUnwanted(ipServer);
+                ipServer.unwanted();
                 return;
             }
         }
@@ -1779,7 +1775,9 @@
 
     void setUsbTethering(boolean enable, IIntResultListener listener) {
         mHandler.post(() -> {
-            sendTetherResult(listener, setUsbTethering(enable));
+            try {
+                listener.onResult(setUsbTethering(enable));
+            } catch (RemoteException e) { }
         });
     }
 
@@ -2906,9 +2904,6 @@
                 tetherState.lastState = state;
                 tetherState.lastError = lastError;
             } else {
-                // Note: Even if an IpServer exists for this iface, it may be different from "who"
-                // if a new IpServer fills the gap before the IpServer.STATE_UNAVAILABLE transition.
-                // TODO: remove this comment once the sync state machine is enabled everywhere.
                 if (DBG) Log.d(TAG, "got notification from stale iface " + iface);
             }
 
@@ -2923,19 +2918,7 @@
             int which;
             switch (state) {
                 case IpServer.STATE_UNAVAILABLE:
-                    which = TetherMainSM.EVENT_IFACE_SERVING_STATE_INACTIVE;
-                    break;
                 case IpServer.STATE_AVAILABLE:
-                    if (lastError != TETHER_ERROR_NO_ERROR) {
-                        // IpServer transitioned from an enabled state (STATE_TETHERED or
-                        // STATE_LOCAL_ONLY) back to STATE_AVAILABLE due to an error, so make sure
-                        // we remove the serving request from RequestTracker.
-                        // TODO: don't continue to use IpServers after they have hit an error, and
-                        // instead move them to STATE_UNAVAILABLE. This code can then
-                        // unconditionally remove the serving request whenever the IpServer enters
-                        // STATE_UNAVAILABLE.
-                        mRequestTracker.removeServingRequest(who);
-                    }
                     which = TetherMainSM.EVENT_IFACE_SERVING_STATE_INACTIVE;
                     break;
                 case IpServer.STATE_TETHERED:
@@ -3031,18 +3014,11 @@
         final TetherState tetherState = mTetherStates.get(iface);
         if (tetherState == null) return;
 
-        mRequestTracker.removeServingRequest(tetherState.ipServer);
         tetherState.ipServer.stop();
         mLog.i("removing IpServer for: " + iface);
         mTetherStates.remove(iface);
     }
 
-    private void ensureIpServerUnwanted(final IpServer ipServer) {
-        mLog.i("unrequesting IpServer: " + ipServer);
-        mRequestTracker.removeServingRequest(ipServer);
-        ipServer.unwanted();
-    }
-
     private static String[] copy(String[] strarray) {
         return Arrays.copyOf(strarray, strarray.length);
     }
@@ -3050,7 +3026,9 @@
     void setPreferTestNetworks(final boolean prefer, IIntResultListener listener) {
         mHandler.post(() -> {
             mUpstreamNetworkMonitor.setPreferTestNetworks(prefer);
-            sendTetherResult(listener, TETHER_ERROR_NO_ERROR);
+            try {
+                listener.onResult(TETHER_ERROR_NO_ERROR);
+            } catch (RemoteException e) { }
         });
     }
 
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/RequestTrackerTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/RequestTrackerTest.java
index 086f2d2..e00e9f0 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/RequestTrackerTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/RequestTrackerTest.java
@@ -18,22 +18,19 @@
 
 import static android.net.TetheringManager.TETHERING_USB;
 import static android.net.TetheringManager.TETHERING_WIFI;
-import static android.net.TetheringManager.TETHERING_VIRTUAL;
 
 import static com.android.networkstack.tethering.util.TetheringUtils.createPlaceholderRequest;
 
 import static com.google.common.truth.Truth.assertThat;
 
-import static org.mockito.Mockito.mock;
-
 import android.net.TetheringManager.TetheringRequest;
-import android.net.ip.IpServer;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.filters.SmallTest;
 
 import com.android.networkstack.tethering.RequestTracker.AddResult;
 
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -42,10 +39,13 @@
 public class RequestTrackerTest {
     private RequestTracker mRequestTracker;
 
+    @Before
+    public void setUp() {
+        mRequestTracker = new RequestTracker();
+    }
+
     @Test
     public void testNoRequestsAdded_noPendingRequests() {
-        mRequestTracker = new RequestTracker(false);
-
         assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isNull();
         assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI))
                 .isEqualTo(createPlaceholderRequest(TETHERING_WIFI));
@@ -53,7 +53,6 @@
 
     @Test
     public void testAddRequest_successResultAndBecomesNextPending() {
-        mRequestTracker = new RequestTracker(false);
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
 
         final AddResult result = mRequestTracker.addPendingRequest(request);
@@ -65,7 +64,6 @@
 
     @Test
     public void testAddRequest_equalRequestExists_successResultAndBecomesNextPending() {
-        mRequestTracker = new RequestTracker(false);
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
         mRequestTracker.addPendingRequest(request);
 
@@ -79,7 +77,6 @@
 
     @Test
     public void testAddRequest_equalButDifferentUidRequest_successResultAndBecomesNextPending() {
-        mRequestTracker = new RequestTracker(false);
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
         request.setUid(1000);
         request.setPackageName("package");
@@ -97,8 +94,7 @@
     }
 
     @Test
-    public void testAddRequest_conflictingPendingRequest_returnsFailureConflictingRequestRestart() {
-        mRequestTracker = new RequestTracker(false);
+    public void testAddConflictingRequest_returnsFailureConflictingPendingRequest() {
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
         final TetheringRequest conflictingRequest = new TetheringRequest.Builder(TETHERING_WIFI)
                 .setExemptFromEntitlementCheck(true).build();
@@ -106,139 +102,13 @@
 
         final AddResult result = mRequestTracker.addPendingRequest(conflictingRequest);
 
-        assertThat(result).isEqualTo(AddResult.FAILURE_DUPLICATE_REQUEST_RESTART);
+        assertThat(result).isEqualTo(AddResult.FAILURE_CONFLICTING_PENDING_REQUEST);
         assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isEqualTo(request);
         assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI)).isEqualTo(request);
     }
 
     @Test
-    public void testAddRequest_noExistingRequestsFuzzyMatching_returnsSuccess() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-
-        final AddResult result = mRequestTracker.addPendingRequest(request);
-
-        assertThat(result).isEqualTo(AddResult.SUCCESS);
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isEqualTo(request);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI)).isEqualTo(request);
-    }
-
-    @Test
-    public void testAddRequest_conflictingPendingRequestFuzzyMatching_returnsFailure() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        final TetheringRequest conflictingRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setExemptFromEntitlementCheck(true).build();
-        mRequestTracker.addPendingRequest(request);
-
-        final AddResult result = mRequestTracker.addPendingRequest(conflictingRequest);
-
-        assertThat(result).isEqualTo(AddResult.FAILURE_DUPLICATE_REQUEST_ERROR);
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isEqualTo(request);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI)).isEqualTo(request);
-    }
-
-    @Test
-    public void testAddRequest_conflictingServingRequestFuzzyMatching_returnsFailure() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        final TetheringRequest conflictingRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setExemptFromEntitlementCheck(true).build();
-        mRequestTracker.promoteRequestToServing(mock(IpServer.class), request);
-
-        final AddResult result = mRequestTracker.addPendingRequest(conflictingRequest);
-
-        assertThat(result).isEqualTo(AddResult.FAILURE_DUPLICATE_REQUEST_ERROR);
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isNull();
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI))
-                .isEqualTo(createPlaceholderRequest(TETHERING_WIFI));
-    }
-
-    @Test
-    public void testAddRequest_nonMatchingPendingRequestFuzzyMatching_returnsSuccess() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_VIRTUAL).build();
-        final TetheringRequest nonFuzzyMatched = new TetheringRequest.Builder(TETHERING_VIRTUAL)
-                .setInterfaceName("iface")
-                .build();
-        mRequestTracker.addPendingRequest(request);
-
-        final AddResult result = mRequestTracker.addPendingRequest(nonFuzzyMatched);
-
-        assertThat(result).isEqualTo(AddResult.SUCCESS);
-        // Next request is still the first, but verify RequestTracker contains the second request by
-        // seeing if it rejects anything matching the second request
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_VIRTUAL)).isEqualTo(request);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_VIRTUAL))
-                .isEqualTo(request);
-        assertThat(mRequestTracker.addPendingRequestFuzzyMatched(nonFuzzyMatched))
-                .isEqualTo(AddResult.FAILURE_DUPLICATE_REQUEST_ERROR);
-    }
-
-    @Test
-    public void testAddRequest_nonMatchingServingRequestFuzzyMatching_returnsSuccess() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_VIRTUAL).build();
-        final TetheringRequest nonFuzzyMatched = new TetheringRequest.Builder(TETHERING_VIRTUAL)
-                .setInterfaceName("iface")
-                .build();
-        mRequestTracker.promoteRequestToServing(mock(IpServer.class), request);
-
-        final AddResult result = mRequestTracker.addPendingRequest(nonFuzzyMatched);
-
-        assertThat(result).isEqualTo(AddResult.SUCCESS);
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_VIRTUAL))
-                .isEqualTo(nonFuzzyMatched);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_VIRTUAL))
-                .isEqualTo(nonFuzzyMatched);
-    }
-
-    @Test
-    public void testRemovePendingRequest_removesAllPendingRequestsOfType() {
-        mRequestTracker = new RequestTracker(false);
-        final TetheringRequest request1 = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        request1.setUid(1000);
-        request1.setPackageName("package");
-        mRequestTracker.addPendingRequest(request1);
-        final TetheringRequest request2 = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        request2.setUid(2000);
-        request2.setPackageName("package2");
-
-        mRequestTracker.removePendingRequest(request2);
-
-        // Verify request1 isn't pending even though we tried to remove a different request
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isNull();
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI))
-                .isEqualTo(createPlaceholderRequest(TETHERING_WIFI));
-    }
-
-    @Test
-    public void testRemovePendingRequest_fuzzyMatching_onlyTheEqualRequestIsRemoved() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request1 = new TetheringRequest.Builder(TETHERING_VIRTUAL).build();
-        final TetheringRequest request2 = new TetheringRequest.Builder(TETHERING_VIRTUAL)
-                .setInterfaceName("iface")
-                .build();
-        mRequestTracker.addPendingRequest(request1);
-        mRequestTracker.addPendingRequest(request2);
-
-        mRequestTracker.removePendingRequest(request2);
-
-        // Verify request1 is still pending.
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_VIRTUAL)).isEqualTo(request1);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_VIRTUAL))
-                .isEqualTo(request1);
-        assertThat(mRequestTracker.addPendingRequestFuzzyMatched(request1))
-                .isEqualTo(AddResult.FAILURE_DUPLICATE_REQUEST_ERROR);
-        // Verify we've removed request2 by checking if it can be added back without
-        // FAILURE_CONFLICTING_REQUEST_FAIL.
-        assertThat(mRequestTracker.addPendingRequestFuzzyMatched(request2))
-                .isEqualTo(AddResult.SUCCESS);
-    }
-
-    @Test
     public void testRemoveAllPendingRequests_noPendingRequestsLeft() {
-        mRequestTracker = new RequestTracker(false);
         final TetheringRequest firstRequest = new TetheringRequest.Builder(TETHERING_WIFI).build();
         firstRequest.setUid(1000);
         firstRequest.setPackageName("package");
@@ -257,7 +127,6 @@
 
     @Test
     public void testRemoveAllPendingRequests_differentTypeExists_doesNotRemoveDifferentType() {
-        mRequestTracker = new RequestTracker(false);
         final TetheringRequest differentType = new TetheringRequest.Builder(TETHERING_USB).build();
         mRequestTracker.addPendingRequest(differentType);
 
@@ -267,61 +136,4 @@
         assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_USB))
                 .isEqualTo(differentType);
     }
-
-    @Test
-    public void testPromoteRequestToServing_requestIsntPendingAnymore() {
-        mRequestTracker = new RequestTracker(false);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        mRequestTracker.addPendingRequest(request);
-
-        mRequestTracker.promoteRequestToServing(mock(IpServer.class), request);
-
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isNull();
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI))
-                .isEqualTo(createPlaceholderRequest(TETHERING_WIFI));
-    }
-
-    @Test
-    public void testPromoteRequestToServing_fuzzyMatching_requestIsntPendingAnymore() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        mRequestTracker.addPendingRequest(request);
-
-        mRequestTracker.promoteRequestToServing(mock(IpServer.class), request);
-
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isNull();
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI))
-                .isEqualTo(createPlaceholderRequest(TETHERING_WIFI));
-    }
-
-    @Test
-    public void testRemoveServingRequest_fuzzyMatching_requestCanBeAddedAgain() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        mRequestTracker.addPendingRequest(request);
-        IpServer ipServer = mock(IpServer.class);
-        mRequestTracker.promoteRequestToServing(ipServer, request);
-
-        mRequestTracker.removeServingRequest(ipServer);
-
-        AddResult result = mRequestTracker.addPendingRequest(request);
-        assertThat(result).isEqualTo(AddResult.SUCCESS);
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isEqualTo(request);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI)).isEqualTo(request);
-    }
-
-    @Test
-    public void testRemoveAllServingRequests_fuzzyMatching_requestCanBeAddedAgain() {
-        mRequestTracker = new RequestTracker(true);
-        final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
-        mRequestTracker.addPendingRequest(request);
-        mRequestTracker.promoteRequestToServing(mock(IpServer.class), request);
-
-        mRequestTracker.removeAllServingRequests(TETHERING_WIFI);
-
-        AddResult result = mRequestTracker.addPendingRequest(request);
-        assertThat(result).isEqualTo(AddResult.SUCCESS);
-        assertThat(mRequestTracker.getNextPendingRequest(TETHERING_WIFI)).isEqualTo(request);
-        assertThat(mRequestTracker.getOrCreatePendingRequest(TETHERING_WIFI)).isEqualTo(request);
-    }
 }
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
index 8ecaec9..2a22c6d 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -50,18 +50,15 @@
 import static android.net.TetheringManager.TETHERING_VIRTUAL;
 import static android.net.TetheringManager.TETHERING_WIFI;
 import static android.net.TetheringManager.TETHERING_WIFI_P2P;
-import static android.net.TetheringManager.TETHER_ERROR_DUPLICATE_REQUEST;
 import static android.net.TetheringManager.TETHER_ERROR_IFACE_CFG_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_INTERNAL_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
 import static android.net.TetheringManager.TETHER_ERROR_SERVICE_UNAVAIL;
 import static android.net.TetheringManager.TETHER_ERROR_UNKNOWN_IFACE;
-import static android.net.TetheringManager.TETHER_ERROR_UNKNOWN_REQUEST;
 import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_FAILED;
 import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_STARTED;
 import static android.net.TetheringManager.TETHER_HARDWARE_OFFLOAD_STOPPED;
 import static android.net.dhcp.IDhcpServer.STATUS_SUCCESS;
-import static android.net.dhcp.IDhcpServer.STATUS_UNKNOWN_ERROR;
 import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_INTERFACE_NAME;
 import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_MODE;
 import static android.net.wifi.WifiManager.EXTRA_WIFI_AP_STATE;
@@ -96,7 +93,6 @@
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
-import static org.junit.Assume.assumeFalse;
 import static org.junit.Assume.assumeTrue;
 import static org.mockito.ArgumentMatchers.argThat;
 import static org.mockito.ArgumentMatchers.notNull;
@@ -201,7 +197,6 @@
 import com.android.internal.util.test.BroadcastInterceptingContext;
 import com.android.internal.util.test.FakeSettingsProvider;
 import com.android.modules.utils.build.SdkLevel;
-import com.android.net.flags.Flags;
 import com.android.net.module.util.CollectionUtils;
 import com.android.net.module.util.InterfaceParams;
 import com.android.net.module.util.PrivateAddressCoordinator;
@@ -313,7 +308,8 @@
     @Mock private TetheringMetrics mTetheringMetrics;
     @Mock private PrivateAddressCoordinator.Dependencies mPrivateAddressCoordinatorDependencies;
 
-    private MockIpServerDependencies mIpServerDependencies;
+    private final MockIpServerDependencies mIpServerDependencies =
+            spy(new MockIpServerDependencies());
     private final MockTetheringDependencies mTetheringDependencies =
             new MockTetheringDependencies();
 
@@ -400,9 +396,6 @@
     }
 
     public class MockIpServerDependencies extends IpServer.Dependencies {
-
-        private int mOnDhcpServerCreatedResult = STATUS_SUCCESS;
-
         @Override
         public DadProxy getDadProxy(
                 Handler handler, InterfaceParams ifParams) {
@@ -444,7 +437,7 @@
                 DhcpServerCallbacks cb) {
             new Thread(() -> {
                 try {
-                    cb.onDhcpServerCreated(mOnDhcpServerCreatedResult, mDhcpServer);
+                    cb.onDhcpServerCreated(STATUS_SUCCESS, mDhcpServer);
                 } catch (RemoteException e) {
                     fail(e.getMessage());
                 }
@@ -455,10 +448,6 @@
                 IpNeighborMonitor.NeighborEventConsumer c) {
             return mIpNeighborMonitor;
         }
-
-        public void setOnDhcpServerCreatedResult(final int result) {
-            mOnDhcpServerCreatedResult = result;
-        }
     }
 
     public class MockTetheringDependencies extends TetheringDependencies {
@@ -719,7 +708,6 @@
 
         when(mPackageManager.hasSystemFeature(PackageManager.FEATURE_WIFI)).thenReturn(true);
         when(mPackageManager.hasSystemFeature(PackageManager.FEATURE_WIFI_DIRECT)).thenReturn(true);
-        mIpServerDependencies = spy(new MockIpServerDependencies());
     }
 
     // In order to interact with syncSM from the test, tethering must be created in test thread.
@@ -2437,7 +2425,7 @@
 
     @Test
     public void testSoftApConfigInTetheringEventCallback() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
+        assumeTrue(SdkLevel.isAtLeastV());
         when(mContext.checkCallingOrSelfPermission(NETWORK_SETTINGS))
                 .thenReturn(PERMISSION_DENIED);
         when(mContext.checkCallingOrSelfPermission(NETWORK_STACK))
@@ -2494,12 +2482,14 @@
         // Enable wifi tethering
         mBinderCallingUid = TEST_CALLER_UID;
         mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, null);
-        mLooper.dispatchAll();
         mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
         mLooper.dispatchAll();
-        // Netd "up" event should not trigger a state change callback in B+.
-        callback.assertNoStateChangeCallback();
+        if (SdkLevel.isAtLeastB()) {
+            // Starting in B, ignore the interfaceStatusChanged
+            callback.assertNoStateChangeCallback();
+        }
         sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
+        mLooper.dispatchAll();
         // Verify we see  Available -> Tethered states
         assertArrayEquals(new TetheringInterface[] {wifiIfaceWithoutConfig},
                 callback.pollTetherStatesChanged().availableList);
@@ -2517,15 +2507,20 @@
         callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STARTED);
 
         // Disable wifi tethering
-        mTethering.stopTethering(TETHERING_WIFI);
         mLooper.dispatchAll();
-        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME,
+        mTethering.stopTethering(TETHERING_WIFI);
+        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED);
+        if (isAtLeastT()) {
+            // After T, tethering doesn't support WIFI_AP_STATE_DISABLED with null interface name.
+            callback.assertNoStateChangeCallback();
+            sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME,
                     IFACE_IP_MODE_TETHERED);
-        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithoutConfig},
+        }
+        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithConfig},
                 callback.pollTetherStatesChanged().availableList);
         assertArrayEquals(new TetheringInterface[] {wifiIfaceWithoutConfig},
                 differentCallback.pollTetherStatesChanged().availableList);
-        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithoutConfig},
+        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithConfig},
                 settingsCallback.pollTetherStatesChanged().availableList);
         mLooper.dispatchAll();
         callback.expectUpstreamChanged(NULL_NETWORK);
@@ -2533,332 +2528,6 @@
         callback.assertNoCallback();
     }
 
-    private boolean isTetheringWithSoftApConfigEnabled() {
-        return SdkLevel.isAtLeastB() && Flags.tetheringWithSoftApConfig();
-    }
-
-    @Test
-    public void testFuzzyMatchedWifiCannotBeAdded() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        initTetheringOnTestThread();
-        TestTetheringEventCallback callback = new TestTetheringEventCallback();
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder().setWifiSsid(
-                WifiSsid.fromBytes("SoftApConfig".getBytes(StandardCharsets.UTF_8))).build();
-        final TetheringInterface wifiIfaceWithoutConfig = new TetheringInterface(
-                TETHERING_WIFI, TEST_WLAN_IFNAME, null);
-        final TetheringInterface wifiIfaceWithConfig = new TetheringInterface(
-                TETHERING_WIFI, TEST_WLAN_IFNAME, softApConfig);
-
-        // Register callback before running any tethering.
-        mTethering.registerTetheringEventCallback(callback);
-        mLooper.dispatchAll();
-        callback.expectTetheredClientChanged(Collections.emptyList());
-        callback.expectUpstreamChanged(NULL_NETWORK);
-        callback.expectConfigurationChanged(
-                mTethering.getTetheringConfiguration().toStableParcelable());
-        assertTetherStatesNotNullButEmpty(callback.pollTetherStatesChanged());
-        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STOPPED);
-        UpstreamNetworkState upstreamState = buildMobileDualStackUpstreamState();
-        initTetheringUpstream(upstreamState);
-
-        // Start wifi tethering but don't trigger the link layer event yet.
-        mBinderCallingUid = TEST_CALLER_UID;
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        tetheringRequest.setUid(TEST_CALLER_UID);
-        ResultListener successListener = new ResultListener(TETHER_ERROR_NO_ERROR);
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener);
-        mLooper.dispatchAll();
-        successListener.assertHasResult();
-
-        // Try starting wifi tethering with various fuzzy-matching requests and verify we get
-        // TETHER_ERROR_DUPLICATE_REQUEST.
-
-        // Different static IP addresses
-        final TetheringRequest differentIpAddr = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig)
-                .setStaticIpv4Addresses(new LinkAddress("192.168.0.123/24"),
-                        new LinkAddress("192.168.0.42/24"))
-                .build();
-        differentIpAddr.setUid(TEST_CALLER_UID);
-        ResultListener differentIpAddrListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(differentIpAddr, TEST_CALLER_PKG, differentIpAddrListener);
-        mLooper.dispatchAll();
-        verify(mWifiManager, times(1)).startTetheredHotspot(any());
-        verify(mWifiManager, never()).stopSoftAp();
-        differentIpAddrListener.assertHasResult();
-
-        // Different UID
-        final TetheringRequest differentUid = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        differentUid.setUid(TEST_CALLER_UID + 1);
-        ResultListener differentUidListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(differentUid, TEST_CALLER_PKG, differentUidListener);
-        mLooper.dispatchAll();
-        differentUidListener.assertHasResult();
-        verify(mWifiManager, times(1)).startTetheredHotspot(any());
-        verify(mWifiManager, never()).stopSoftAp();
-
-        // Mock the link layer event to start IP serving and verify we still get
-        // TETHER_ERROR_DUPLICATE_REQUEST even though the request is no longer pending and is
-        // already serving.
-        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
-        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithoutConfig},
-                callback.pollTetherStatesChanged().availableList);
-        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithConfig},
-                callback.pollTetherStatesChanged().tetheredList);
-        callback.expectUpstreamChanged(upstreamState.network);
-        callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STARTED);
-        differentIpAddrListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        differentUidListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(differentIpAddr, TEST_CALLER_PKG, differentIpAddrListener);
-        mTethering.startTethering(differentUid, TEST_CALLER_PKG, differentUidListener);
-        mLooper.dispatchAll();
-        differentIpAddrListener.assertHasResult();
-        differentUidListener.assertHasResult();
-        verify(mWifiManager, times(1)).startTetheredHotspot(any());
-        verify(mWifiManager, never()).stopSoftAp();
-    }
-
-    @Test
-    public void testFuzzyMatchedWifiCanBeAddedAfterIpServerStopped() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-        initTetheringOnTestThread();
-
-        // Start wifi tethering and mock the ap state change.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder().setWifiSsid(
-                WifiSsid.fromBytes("SoftApConfig".getBytes(StandardCharsets.UTF_8))).build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        ResultListener successListener = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener);
-        mLooper.dispatchAll();
-        successListener.assertHasResult();
-        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
-
-        // Starting wifi again will cause TETHER_ERROR_DUPLICATE_REQUEST
-        ResultListener failureListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, failureListener);
-        mLooper.dispatchAll();
-        failureListener.assertHasResult();
-
-        // Trigger Netd callback to stop the IpServer
-        mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, false);
-
-        // We should be able to request the same Wifi again
-        ResultListener successListener2 = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener2);
-        mLooper.dispatchAll();
-        successListener2.assertHasResult();
-    }
-
-    @Test
-    public void testFuzzyMatchedWifiCanBeAddedAfterIpServerUnwanted() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-        initTetheringOnTestThread();
-
-        // Start wifi tethering and mock the ap state change.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder().setWifiSsid(
-                WifiSsid.fromBytes("SoftApConfig".getBytes(StandardCharsets.UTF_8))).build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        ResultListener successListener = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener);
-        mLooper.dispatchAll();
-        successListener.assertHasResult();
-        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
-
-        // Starting wifi again will cause TETHER_ERROR_DUPLICATE_REQUEST
-        ResultListener failureListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, failureListener);
-        mLooper.dispatchAll();
-        failureListener.assertHasResult();
-
-        // Trigger wifi ap state change to tell IpServer it's unwanted.
-        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
-
-        // We should be able to request the same Wifi again
-        ResultListener successListener2 = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener2);
-        mLooper.dispatchAll();
-        successListener2.assertHasResult();
-    }
-
-    @Test
-    public void testFuzzyMatchedWifiCanBeAddedAfterIpServerError() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-        initTetheringOnTestThread();
-
-        // Set up the DHCP server to fail creation.
-        mIpServerDependencies.setOnDhcpServerCreatedResult(STATUS_UNKNOWN_ERROR);
-
-        // Start wifi tethering and mock the ap state change.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder().setWifiSsid(
-                WifiSsid.fromBytes("SoftApConfig".getBytes(StandardCharsets.UTF_8))).build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        ResultListener successListener = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener);
-        mLooper.dispatchAll();
-        successListener.assertHasResult();
-        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
-
-        // We should be able to request the same Wifi again since the DHCP server transitioned the
-        // IpServer back to InitialState.
-        ResultListener successListener2 = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener2);
-        mLooper.dispatchAll();
-        successListener2.assertHasResult();
-    }
-
-    @Test
-    public void testFuzzyMatchedWifiCanBeAddedAfterStoppingPendingRequest() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-        initTetheringOnTestThread();
-
-        // Start wifi tethering but keep the request pending by not sending the ap state change.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder().setWifiSsid(
-                WifiSsid.fromBytes("SoftApConfig".getBytes(StandardCharsets.UTF_8))).build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        ResultListener successListener = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener);
-        mLooper.dispatchAll();
-        successListener.assertHasResult();
-
-        // Starting wifi again will cause TETHER_ERROR_DUPLICATE_REQUEST
-        ResultListener failureListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, failureListener);
-        mLooper.dispatchAll();
-        failureListener.assertHasResult();
-
-        // Stop Wifi tethering.
-        mTethering.stopTethering(TETHERING_WIFI);
-
-        // We should be able to request the same Wifi again
-        ResultListener successListener2 = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener2);
-        mLooper.dispatchAll();
-        successListener2.assertHasResult();
-    }
-
-    @Test
-    public void testFuzzyMatchedWifiCanBeAddedAfterStoppingServingRequest() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-        initTetheringOnTestThread();
-
-        // Start wifi tethering and mock the ap state change.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder().setWifiSsid(
-                WifiSsid.fromBytes("SoftApConfig".getBytes(StandardCharsets.UTF_8))).build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        ResultListener successListener = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener);
-        mLooper.dispatchAll();
-        successListener.assertHasResult();
-        sendWifiApStateChanged(WIFI_AP_STATE_ENABLED, TEST_WLAN_IFNAME, IFACE_IP_MODE_TETHERED);
-
-        // Starting wifi again will cause TETHER_ERROR_DUPLICATE_REQUEST
-        ResultListener failureListener = new ResultListener(TETHER_ERROR_DUPLICATE_REQUEST);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, failureListener);
-        mLooper.dispatchAll();
-        failureListener.assertHasResult();
-
-        // Stop Wifi tethering.
-        mTethering.stopTethering(TETHERING_WIFI);
-
-        // We should be able to request the same Wifi again
-        ResultListener successListener2 = new ResultListener(TETHER_ERROR_NO_ERROR);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, successListener2);
-        mLooper.dispatchAll();
-        successListener2.assertHasResult();
-    }
-
-    @Test
-    public void testStopTetheringWithMatchingRequest() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        when(mContext.checkCallingOrSelfPermission(NETWORK_SETTINGS)).thenReturn(PERMISSION_DENIED);
-        initTetheringOnTestThread();
-        UpstreamNetworkState upstreamState = buildMobileDualStackUpstreamState();
-        initTetheringUpstream(upstreamState);
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-
-        // Enable wifi tethering.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder()
-                .setSsid("SoftApConfig")
-                .build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        tetheringRequest.setUid(TEST_CALLER_UID);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, null);
-        mLooper.dispatchAll();
-
-        // Stop tethering with non-matching config. Should fail with TETHER_ERROR_UNKNOWN_REQUEST.
-        SoftApConfiguration softApConfig2 = new SoftApConfiguration.Builder()
-                .setSsid("SoftApConfig2")
-                .build();
-        IIntResultListener differentConfigListener = mock(IIntResultListener.class);
-        mTethering.stopTetheringRequest(new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig2).build(), differentConfigListener);
-        mLooper.dispatchAll();
-        verify(differentConfigListener).onResult(eq(TETHER_ERROR_UNKNOWN_REQUEST));
-        verify(mWifiManager, never()).stopSoftAp();
-
-        // Stop tethering with non-matching UID. Should fail with TETHER_ERROR_UNKNOWN_REQUEST.
-        final TetheringRequest nonMatchingUid = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        IIntResultListener nonMatchingUidListener = mock(IIntResultListener.class);
-        nonMatchingUid.setUid(TEST_CALLER_UID_2);
-        mTethering.stopTetheringRequest(nonMatchingUid, nonMatchingUidListener);
-        mLooper.dispatchAll();
-        verify(nonMatchingUidListener).onResult(eq(TETHER_ERROR_UNKNOWN_REQUEST));
-        verify(mWifiManager, never()).stopSoftAp();
-
-        // Stop tethering with matching request. Should succeed now.
-        IIntResultListener matchingListener = mock(IIntResultListener.class);
-        mTethering.stopTetheringRequest(tetheringRequest, matchingListener);
-        mLooper.dispatchAll();
-        verify(matchingListener).onResult(eq(TETHER_ERROR_NO_ERROR));
-        verify(mWifiManager).stopSoftAp();
-    }
-
-    @Test
-    public void testStopTetheringWithSettingsPermission() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        initTetheringOnTestThread();
-        UpstreamNetworkState upstreamState = buildMobileDualStackUpstreamState();
-        initTetheringUpstream(upstreamState);
-        when(mWifiManager.startTetheredHotspot(null)).thenReturn(true);
-
-        // Enable wifi tethering.
-        SoftApConfiguration softApConfig = new SoftApConfiguration.Builder()
-                .setSsid("SoftApConfig")
-                .build();
-        final TetheringRequest tetheringRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        tetheringRequest.setUid(TEST_CALLER_UID);
-        mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, null);
-        mLooper.dispatchAll();
-
-        // Stop tethering with non-matching UID and Settings permission. Should succeed.
-        final TetheringRequest nonMatchingUid = new TetheringRequest.Builder(TETHERING_WIFI)
-                .setSoftApConfiguration(softApConfig).build();
-        IIntResultListener nonMatchingUidListener = mock(IIntResultListener.class);
-        nonMatchingUid.setUid(TEST_CALLER_UID_2);
-        when(mContext.checkCallingOrSelfPermission(NETWORK_SETTINGS))
-                .thenReturn(PERMISSION_GRANTED);
-        mTethering.stopTetheringRequest(nonMatchingUid, nonMatchingUidListener);
-        mLooper.dispatchAll();
-        verify(nonMatchingUidListener).onResult(eq(TETHER_ERROR_NO_ERROR));
-        verify(mWifiManager).stopSoftAp();
-    }
-
     @Test
     public void testReportFailCallbackIfOffloadNotSupported() throws Exception {
         initTetheringOnTestThread();
@@ -3125,8 +2794,7 @@
     }
 
     @Test
-    public void testMultipleStartTetheringLegacy() throws Exception {
-        assumeFalse(isTetheringWithSoftApConfigEnabled());
+    public void testMultipleStartTethering() throws Exception {
         initTetheringOnTestThread();
         final LinkAddress serverLinkAddr = new LinkAddress("192.168.20.1/24");
         final LinkAddress clientLinkAddr = new LinkAddress("192.168.20.42/24");
@@ -3907,7 +3575,6 @@
     @Test
     public void testStartBluetoothTetheringFailsWhenTheresAnExistingRequestWaitingForPanService()
             throws Exception {
-        assumeFalse(isTetheringWithSoftApConfigEnabled());
         initTetheringOnTestThread();
 
         mockBluetoothSettings(true /* bluetoothOn */, true /* tetheringOn */);
diff --git a/staticlibs/testutils/host/python/apf_utils.py b/staticlibs/testutils/host/python/apf_utils.py
index 49ffad6..c2ad18e 100644
--- a/staticlibs/testutils/host/python/apf_utils.py
+++ b/staticlibs/testutils/host/python/apf_utils.py
@@ -18,6 +18,7 @@
 from mobly.controllers import android_device
 from mobly.controllers.android_device_lib.adb import AdbError
 from net_tests_utils.host.python import adb_utils, assert_utils
+import functools
 
 
 class PatternNotFoundException(Exception):
@@ -400,6 +401,20 @@
       f" {expected_version}",
   )
 
+def at_least_B():
+  def decorator(test_function):
+    @functools.wraps(test_function)
+    def wrapper(self, *args, **kwargs):
+      asserts.abort_class_if(
+        (not hasattr(self, 'client')) or (not hasattr(self.client, 'isAtLeastB')),
+        "client device is not B+"
+      )
+
+      asserts.abort_class_if(not self.client.isAtLeastB(), "not B+")
+      return test_function(self, *args, **kwargs)
+    return wrapper
+  return decorator
+
 class AdbOutputHandler:
   def __init__(self, ad, cmd):
     self._ad = ad
diff --git a/staticlibs/testutils/host/python/multi_devices_test_base.py b/staticlibs/testutils/host/python/multi_devices_test_base.py
index 677329a..72bac0c 100644
--- a/staticlibs/testutils/host/python/multi_devices_test_base.py
+++ b/staticlibs/testutils/host/python/multi_devices_test_base.py
@@ -53,3 +53,4 @@
         raise_on_exception=True,
     )
     self.client = self.clientDevice.connectivity_multi_devices_snippet
+    self.server = self.serverDevice.connectivity_multi_devices_snippet
diff --git a/tests/cts/multidevices/Android.bp b/tests/cts/multidevices/Android.bp
index c730b86..00fb934 100644
--- a/tests/cts/multidevices/Android.bp
+++ b/tests/cts/multidevices/Android.bp
@@ -29,6 +29,7 @@
     libs: [
         "absl-py",
         "mobly",
+        "scapy",
         "net-tests-utils-host-python-common",
     ],
     test_suites: [
diff --git a/tests/cts/multidevices/apfv6_test.py b/tests/cts/multidevices/apfv6_test.py
index fc732d2..61f1bfc 100644
--- a/tests/cts/multidevices/apfv6_test.py
+++ b/tests/cts/multidevices/apfv6_test.py
@@ -13,6 +13,8 @@
 #  limitations under the License.
 
 from mobly import asserts
+from scapy.layers.inet import IP, ICMP
+from scapy.layers.l2 import Ether
 from net_tests_utils.host.python import apf_test_base, apf_utils, adb_utils, assert_utils, packet_utils
 
 APFV6_VERSION = 6000
@@ -82,3 +84,18 @@
         self.send_packet_and_expect_reply_received(
             arp_request, "DROPPED_ARP_REQUEST_REPLIED", arp_reply
         )
+
+    @apf_utils.at_least_B()
+    def test_ipv4_icmp_echo_request_offload(self):
+        eth = Ether(src=self.server_mac_address, dst=self.client_mac_address)
+        ip = IP(src=self.server_ipv4_addresses[0], dst=self.client_ipv4_addresses[0])
+        icmp = ICMP(id=1, seq=123)
+        echo_request = bytes(eth/ip/icmp/b"hello").hex()
+
+        eth = Ether(src=self.client_mac_address, dst=self.server_mac_address)
+        ip = IP(src=self.client_ipv4_addresses[0], dst=self.server_ipv4_addresses[0])
+        icmp = ICMP(type=0, id=1, seq=123)
+        expected_echo_reply = bytes(eth/ip/icmp/b"hello").hex()
+        self.send_packet_and_expect_reply_received(
+            echo_request, "DROPPED_IPV4_PING_REQUEST_REPLIED", expected_echo_reply
+        )
\ No newline at end of file
diff --git a/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt b/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
index 252052e..e1c6bf1 100644
--- a/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
+++ b/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
@@ -33,6 +33,8 @@
 import android.net.wifi.WifiInfo
 import android.net.wifi.WifiManager
 import android.net.wifi.WifiSsid
+import android.os.Build.VERSION.CODENAME
+import android.os.Build.VERSION.SDK_INT
 import androidx.test.platform.app.InstrumentationRegistry
 import com.android.compatibility.common.util.PropertyUtil
 import com.android.modules.utils.build.SdkLevel
@@ -62,6 +64,17 @@
         cbHelper.unregisterAll()
     }
 
+    private fun isAtLeastPreReleaseCodename(codeName: String): Boolean {
+        // Special case "REL", which means the build is not a pre-release build.
+        if ("REL".equals(CODENAME)) {
+            return false
+        }
+
+        // Otherwise lexically compare them. Return true if the build codename is equal to or
+        // greater than the requested codename.
+        return CODENAME.compareTo(codeName) >= 0
+    }
+
     @Rpc(description = "Check whether the device has wifi feature.")
     fun hasWifiFeature() = pm.hasSystemFeature(FEATURE_WIFI)
 
@@ -77,6 +90,11 @@
     @Rpc(description = "Return whether the Sdk level is at least V.")
     fun isAtLeastV() = SdkLevel.isAtLeastV()
 
+    @Rpc(description = "Check whether the device is at least B.")
+    fun isAtLeastB(): Boolean {
+        return SDK_INT >= 36 || (SDK_INT == 35 && isAtLeastPreReleaseCodename("Baklava"))
+    }
+
     @Rpc(description = "Return the API level that the VSR requirement must be fulfilled.")
     fun getVsrApiLevel() = PropertyUtil.getVsrApiLevel()
 
diff --git a/tests/cts/tethering/src/android/tethering/cts/TetheringManagerTest.java b/tests/cts/tethering/src/android/tethering/cts/TetheringManagerTest.java
index ed6107b..e645f67 100644
--- a/tests/cts/tethering/src/android/tethering/cts/TetheringManagerTest.java
+++ b/tests/cts/tethering/src/android/tethering/cts/TetheringManagerTest.java
@@ -32,7 +32,6 @@
 import static android.net.TetheringManager.TETHERING_VIRTUAL;
 import static android.net.TetheringManager.TETHERING_WIFI;
 import static android.net.TetheringManager.TETHERING_WIFI_P2P;
-import static android.net.TetheringManager.TETHER_ERROR_DUPLICATE_REQUEST;
 import static android.net.TetheringManager.TETHER_ERROR_ENTITLEMENT_UNKNOWN;
 import static android.net.TetheringManager.TETHER_ERROR_NO_CHANGE_TETHERING_PERMISSION;
 import static android.net.TetheringManager.TETHER_ERROR_NO_ERROR;
@@ -235,30 +234,6 @@
 
     }
 
-    @Test
-    public void testStartTetheringDuplicateRequestRejected() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        final TestTetheringEventCallback tetherEventCallback =
-                mCtsTetheringUtils.registerTetheringEventCallback();
-        try {
-            tetherEventCallback.assumeWifiTetheringSupported(mContext);
-            tetherEventCallback.expectNoTetheringActive();
-
-            final String[] wifiRegexs = mTM.getTetherableWifiRegexs();
-            mCtsTetheringUtils.startWifiTethering(tetherEventCallback);
-            mTetherChangeReceiver.expectTethering(true /* active */, wifiRegexs);
-
-            final StartTetheringCallback startTetheringCallback = new StartTetheringCallback();
-            runAsShell(TETHER_PRIVILEGED, () -> {
-                mTM.startTethering(new TetheringRequest.Builder(TETHERING_WIFI).build(),
-                        c -> c.run() /* executor */, startTetheringCallback);
-                startTetheringCallback.expectTetheringFailed(TETHER_ERROR_DUPLICATE_REQUEST);
-            });
-        } finally {
-            mCtsTetheringUtils.unregisterTetheringEventCallback(tetherEventCallback);
-        }
-    }
-
     private SoftApConfiguration createSoftApConfiguration(@NonNull String ssid) {
         SoftApConfiguration config;
         if (SdkLevel.isAtLeastT()) {
@@ -405,20 +380,17 @@
             tetherEventCallback.assumeWifiTetheringSupported(mContext);
             tetherEventCallback.expectNoTetheringActive();
 
-            SoftApConfiguration softApConfig = isTetheringWithSoftApConfigEnabled()
-                    ? createSoftApConfiguration("SSID") : null;
+            SoftApConfiguration softApConfig = createSoftApConfiguration("SSID");
             final TetheringInterface tetheredIface =
                     mCtsTetheringUtils.startWifiTethering(tetherEventCallback, softApConfig);
 
             assertNotNull(tetheredIface);
-            if  (isTetheringWithSoftApConfigEnabled()) {
-                assertEquals(softApConfig, tetheredIface.getSoftApConfiguration());
-            }
+            assertEquals(softApConfig, tetheredIface.getSoftApConfiguration());
+            final String wifiTetheringIface = tetheredIface.getInterface();
 
             mCtsTetheringUtils.stopWifiTethering(tetherEventCallback);
 
             if (!SdkLevel.isAtLeastB()) {
-                final String wifiTetheringIface = tetheredIface.getInterface();
                 try {
                     final int ret = runAsShell(TETHER_PRIVILEGED,
                             () -> mTM.tether(wifiTetheringIface));
@@ -483,73 +455,25 @@
     }
 
     @Test
-    public void testStopTetheringRequestNoMatchFailure() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        final TestTetheringEventCallback tetherEventCallback =
-                mCtsTetheringUtils.registerTetheringEventCallback();
-        try {
-            final StartTetheringCallback startTetheringCallback = new StartTetheringCallback();
-            mTM.startTethering(new TetheringRequest.Builder(TETHERING_VIRTUAL).build(),
-                    c -> c.run(), startTetheringCallback);
-
-            // Stopping a non-matching request should have no effect
-            TetheringRequest nonMatchingRequest = new TetheringRequest.Builder(TETHERING_VIRTUAL)
-                    .setInterfaceName("iface")
-                    .build();
-            mCtsTetheringUtils.stopTethering(nonMatchingRequest, false /* success */);
-        } finally {
-            mCtsTetheringUtils.unregisterTetheringEventCallback(tetherEventCallback);
-        }
-    }
-
-    @Test
-    public void testStopTetheringRequestMatchSuccess() throws Exception {
+    public void testStopTetheringRequest() throws Exception {
         assumeTrue(isTetheringWithSoftApConfigEnabled());
         final TestTetheringEventCallback tetherEventCallback =
                 mCtsTetheringUtils.registerTetheringEventCallback();
         try {
             tetherEventCallback.assumeWifiTetheringSupported(mContext);
 
-            SoftApConfiguration softApConfig = new SoftApConfiguration.Builder()
-                    .setWifiSsid(WifiSsid.fromBytes("This is one config"
-                            .getBytes(StandardCharsets.UTF_8))).build();
-            mCtsTetheringUtils.startWifiTethering(tetherEventCallback, softApConfig);
+            // stopTethering without any tethering active should fail.
+            TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
+            mCtsTetheringUtils.stopTethering(request, false /* expectSuccess */);
 
-            // Stopping the active request should stop tethering.
-            TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI)
-                    .setSoftApConfiguration(softApConfig)
-                    .build();
-            mCtsTetheringUtils.stopTethering(request, true /* success */);
+            // Start wifi tethering
+            mCtsTetheringUtils.startWifiTethering(tetherEventCallback);
+
+            // stopTethering should succeed now that there's a request.
+            mCtsTetheringUtils.stopTethering(request, true /* expectSuccess */);
             tetherEventCallback.expectNoTetheringActive();
         } finally {
-            mCtsTetheringUtils.unregisterTetheringEventCallback(tetherEventCallback);
-        }
-    }
-
-    @Test
-    public void testStopTetheringRequestFuzzyMatchSuccess() throws Exception {
-        assumeTrue(isTetheringWithSoftApConfigEnabled());
-        final TestTetheringEventCallback tetherEventCallback =
-                mCtsTetheringUtils.registerTetheringEventCallback();
-        try {
-            tetherEventCallback.assumeWifiTetheringSupported(mContext);
-
-            SoftApConfiguration softApConfig = new SoftApConfiguration.Builder()
-                    .setWifiSsid(WifiSsid.fromBytes("This is one config"
-                            .getBytes(StandardCharsets.UTF_8))).build();
-            mCtsTetheringUtils.startWifiTethering(tetherEventCallback, softApConfig);
-
-            // Stopping with a fuzzy matching request should stop tethering.
-            final LinkAddress localAddr = new LinkAddress("192.168.24.5/24");
-            final LinkAddress clientAddr = new LinkAddress("192.168.24.100/24");
-            TetheringRequest fuzzyMatchingRequest = new TetheringRequest.Builder(TETHERING_WIFI)
-                    .setSoftApConfiguration(softApConfig)
-                    .setShouldShowEntitlementUi(true)
-                    .setStaticIpv4Addresses(localAddr, clientAddr)
-                    .build();
-            mCtsTetheringUtils.stopTethering(fuzzyMatchingRequest, true /* success */);
-            tetherEventCallback.expectNoTetheringActive();
-        } finally {
+            mCtsTetheringUtils.stopAllTethering();
             mCtsTetheringUtils.unregisterTetheringEventCallback(tetherEventCallback);
         }
     }