[Revert^2] Reject TetheringRequests that fuzzy-match existing ones am: 8b29d287f5

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3543706

Change-Id: I6ac631f6cb393f406eb7c89036062480e29e40c1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

Tethering/common/TetheringLib/src/android/net/TetheringManager.java

@@ -37,6 +37,7 @@ import android.os.Parcelable;
 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;
@@ -1258,6 +1259,44 @@ public class TetheringManager {
             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
          */
@@ -1279,6 +1318,8 @@ public class TetheringManager {
         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)

Tethering/src/android/net/ip/IpServer.java

@@ -415,12 +415,6 @@ public class IpServer extends StateMachineShim {
         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.

Tethering/src/com/android/networkstack/tethering/RequestTracker.java

@@ -19,6 +19,8 @@ package com.android.networkstack.tethering;
 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;
@@ -28,6 +30,7 @@ import com.android.internal.annotations.VisibleForTesting;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Helper class to keep track of tethering requests.
@@ -36,29 +39,17 @@ import java.util.List;
  *    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 all pending requests with {@link #removeAllPendingRequests(int)}.
+ * 3) Remove pending request with {@link #removePendingRequest(TetheringRequest)}.
  * 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();
 
-    private class PendingRequest {
+    @NonNull
-        @NonNull
+    private final boolean mUseFuzzyMatching;
-        private final TetheringRequest mTetheringRequest;
 
-        private PendingRequest(@NonNull TetheringRequest tetheringRequest) {
+    public RequestTracker(boolean useFuzzyMatching) {
-            mTetheringRequest = tetheringRequest;
+        mUseFuzzyMatching = useFuzzyMatching;
-        }
-
-        @NonNull
-        TetheringRequest getTetheringRequest() {
-            return mTetheringRequest;
-        }
     }
 
     public enum AddResult {
@@ -69,24 +60,51 @@ public class RequestTracker {
         /**
          * 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.
+         * pending request before trying to add the result again. Only returned on V-.
          */
-        FAILURE_CONFLICTING_PENDING_REQUEST
+        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,
     }
 
     /**
-     * List of pending requests added by {@link #addPendingRequest(TetheringRequest)}. There can be
+     * List of pending requests added by {@link #addPendingRequest(TetheringRequest)}
-     * only one per type, since we remove every request of the same type when we add a request.
+     * There can be only one per type, since we remove every request of the
+     * same type when we add a request.
      */
-    private final List<PendingRequest> mPendingRequests = new ArrayList<>();
+    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<>();
 
     @VisibleForTesting
     List<TetheringRequest> getPendingTetheringRequests() {
-        List<TetheringRequest> requests = new ArrayList<>();
+        return new ArrayList<>(mPendingRequests);
-        for (PendingRequest pendingRequest : mPendingRequests) {
+    }
-            requests.add(pendingRequest.getTetheringRequest());
+
+    /**
+     * 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;
+            }
         }
-        return requests;
+
+        mPendingRequests.add(newRequest);
+        return AddResult.SUCCESS;
     }
 
     /**
@@ -95,9 +113,12 @@ public class RequestTracker {
      * 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 (PendingRequest request : mPendingRequests) {
+        for (TetheringRequest existingRequest : mPendingRequests) {
-            TetheringRequest existingRequest = request.getTetheringRequest();
             if (existingRequest.getTetheringType() != newRequest.getTetheringType()) {
                 continue;
             }
@@ -105,7 +126,7 @@ public class RequestTracker {
             // Can't add request if there's a request of the same type with different
             // parameters.
             if (!existingRequest.equalsIgnoreUidPackage(newRequest)) {
-                return AddResult.FAILURE_CONFLICTING_PENDING_REQUEST;
+                return AddResult.FAILURE_DUPLICATE_REQUEST_RESTART;
             }
         }
 
@@ -113,7 +134,7 @@ public class RequestTracker {
         // conflicting parameters above, so these would have been equivalent anyway (except for
         // UID).
         removeAllPendingRequests(newRequest.getTetheringType());
-        mPendingRequests.add(new PendingRequest(newRequest));
+        mPendingRequests.add(newRequest);
         return AddResult.SUCCESS;
     }
 
@@ -145,10 +166,8 @@ public class RequestTracker {
      */
     @Nullable
     public TetheringRequest getNextPendingRequest(int type) {
-        for (PendingRequest pendingRequest : mPendingRequests) {
+        for (TetheringRequest request : mPendingRequests) {
-            TetheringRequest tetheringRequest =
+            if (request.getTetheringType() == type) return request;
-                    pendingRequest.getTetheringRequest();
-            if (tetheringRequest.getTetheringType() == type) return tetheringRequest;
         }
         return null;
     }
@@ -158,7 +177,66 @@ public class RequestTracker {
      *
      * @param type Tethering type
      */
-    public void removeAllPendingRequests(int type) {
+    public void removeAllPendingRequests(final int type) {
-        mPendingRequests.removeIf(r -> r.getTetheringRequest().getTetheringType() == 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);
     }
 }

Tethering/src/com/android/networkstack/tethering/Tethering.java

@@ -43,6 +43,7 @@ import static android.net.TetheringManager.TETHERING_WIFI;
 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;
@@ -67,6 +68,8 @@ import static android.net.wifi.WifiManager.WIFI_AP_STATE_DISABLED;
 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;
@@ -309,7 +312,7 @@ public class Tethering {
         mLooper = mDeps.makeTetheringLooper();
         mNotificationUpdater = mDeps.makeNotificationUpdater(mContext, mLooper);
         mTetheringMetrics = mDeps.makeTetheringMetrics(mContext);
-        mRequestTracker = new RequestTracker();
+        mRequestTracker = new RequestTracker(isTetheringWithSoftApConfigEnabled());
 
         mTetherStates = new ArrayMap<>();
         mConnectedClientsTracker = new ConnectedClientsTracker();
@@ -460,6 +463,7 @@ public class Tethering {
         return mSettingsObserver;
     }
 
+    // TODO: Replace with SdkLevel.isAtLeastB() once the feature is fully implemented.
     boolean isTetheringWithSoftApConfigEnabled() {
         return SdkLevel.isAtLeastB() && Flags.tetheringWithSoftApConfig();
     }
@@ -704,9 +708,16 @@ public class Tethering {
             RequestTracker.AddResult result = mRequestTracker.addPendingRequest(request);
             // If tethering is already pending with a conflicting request, stop tethering before
             // starting.
-            if (result == RequestTracker.AddResult.FAILURE_CONFLICTING_PENDING_REQUEST) {
+            if (result == FAILURE_DUPLICATE_REQUEST_RESTART) {
                 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()) {
@@ -731,7 +742,8 @@ public class Tethering {
         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.
+            // that has not happened yet. This already works if the sync state machine is enabled
+            // (which includes all B+ devices).
             if (state.isCurrentlyServing() && state.ipServer.interfaceType() == type) return true;
         }
         return false;
@@ -742,23 +754,24 @@ public class Tethering {
         if (!isTetheringWithSoftApConfigEnabled()) return;
         mHandler.post(() -> {
             final int type = request.getTetheringType();
+            // TODO: when fuzzy-matching is enabled, check whether any pending request
+            // fuzzy-matches this request instead of just checking the type.
             if (isTetheringTypePendingOrServing(type)) {
                 stopTetheringInternal(type);
-                try {
+                // TODO: We should send the success result after the waiting for tethering to
-                    listener.onResult(TETHER_ERROR_NO_ERROR);
+                //       actually stop.
-                } catch (RemoteException ignored) { }
+                sendTetherResult(listener, TETHER_ERROR_NO_ERROR);
                 return;
             }
 
             // Request doesn't match any active requests, ignore.
-            try {
+            sendTetherResult(listener, TETHER_ERROR_UNKNOWN_REQUEST);
-                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.
@@ -802,21 +815,25 @@ public class Tethering {
         // The result of Bluetooth tethering will be sent after the pan service connects.
         if (result == TETHER_ERROR_BLUETOOTH_SERVICE_PENDING) return;
 
-        sendTetherResult(listener, result, type);
+        sendTetherResultAndRemoveOnError(request, listener, result);
     }
 
-    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.removeAllPendingRequests(type);
+            mRequestTracker.removePendingRequest(request);
+            final int type = request.getTetheringType();
             mTetheringMetrics.updateErrorCode(type, result);
             mTetheringMetrics.sendReport(type);
         }
@@ -862,8 +879,7 @@ public class Tethering {
             // 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;
@@ -904,7 +920,10 @@ public class Tethering {
                 if (mPendingPanRequestListener != null) {
                     final int result = setBluetoothTetheringSettings(mBluetoothPan,
                             true /* enable */);
-                    sendTetherResult(mPendingPanRequestListener, result, TETHERING_BLUETOOTH);
+                    sendTetherResultAndRemoveOnError(
+                            mRequestTracker.getOrCreatePendingRequest(TETHERING_BLUETOOTH),
+                            mPendingPanRequestListener,
+                            result);
                 }
                 mPendingPanRequestListener = null;
             });
@@ -918,8 +937,10 @@ public class Tethering {
                 mIsConnected = false;
 
                 if (mPendingPanRequestListener != null) {
-                    sendTetherResult(mPendingPanRequestListener, TETHER_ERROR_SERVICE_UNAVAIL,
+                    sendTetherResultAndRemoveOnError(
-                            TETHERING_BLUETOOTH);
+                            mRequestTracker.getOrCreatePendingRequest(TETHERING_BLUETOOTH),
+                            mPendingPanRequestListener,
+                            TETHER_ERROR_SERVICE_UNAVAIL);
                 }
                 mPendingPanRequestListener = null;
                 mBluetoothIfaceRequest = null;
@@ -1093,9 +1114,7 @@ public class Tethering {
         final int type = ifaceNameToType(iface);
         if (type == TETHERING_INVALID) {
             Log.e(TAG, "Ignoring call to legacy tether for unknown iface " + iface);
-            try {
+            sendTetherResult(listener, TETHER_ERROR_UNKNOWN_IFACE);
-                listener.onResult(TETHER_ERROR_UNKNOWN_IFACE);
-            } catch (RemoteException e) { }
         }
 
         TetheringRequest request = mRequestTracker.getNextPendingRequest(type);
@@ -1132,9 +1151,7 @@ public class Tethering {
                 // Do nothing
                 break;
         }
-        try {
+        sendTetherResult(listener, result);
-            listener.onResult(result);
-        } catch (RemoteException e) { }
     }
 
     /**
@@ -1167,11 +1184,9 @@ public class Tethering {
             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,
@@ -1191,10 +1206,7 @@ public class Tethering {
             return;
         }
         mHandler.post(() -> {
-            try {
+            sendTetherResult(listener, legacyUntetherInternal(iface));
-                listener.onResult(legacyUntetherInternal(iface));
-            } catch (RemoteException e) {
-            }
         });
     }
 
@@ -1209,7 +1221,7 @@ public class Tethering {
             Log.e(TAG, "Tried to untether an inactive iface :" + iface + ", ignoring");
             return TETHER_ERROR_UNAVAIL_IFACE;
         }
-        tetherState.ipServer.unwanted();
+        ensureIpServerUnwanted(tetherState.ipServer);
         return TETHER_ERROR_NO_ERROR;
     }
 
@@ -1289,7 +1301,12 @@ public class Tethering {
             final TetherState tetherState = mTetherStates.valueAt(i);
             final int type = tetherState.ipServer.interfaceType();
             final String iface = mTetherStates.keyAt(i);
-            final TetheringRequest request = tetherState.ipServer.getTetheringRequest();
+            // 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 boolean includeSoftApConfig = request != null && cookie != null
                     && (cookie.uid == request.getUid() || cookie.hasSystemPrivilege);
             final TetheringInterface tetheringIface = new TetheringInterface(type, iface,
@@ -1611,7 +1628,7 @@ public class Tethering {
 
     private void disableWifiIpServingCommon(int tetheringType, String ifname) {
         if (!TextUtils.isEmpty(ifname) && mTetherStates.containsKey(ifname)) {
-            mTetherStates.get(ifname).ipServer.unwanted();
+            ensureIpServerUnwanted(mTetherStates.get(ifname).ipServer);
             return;
         }
 
@@ -1628,7 +1645,7 @@ public class Tethering {
         for (int i = 0; i < mTetherStates.size(); i++) {
             final IpServer ipServer = mTetherStates.valueAt(i).ipServer;
             if (ipServer.interfaceType() == tetheringType) {
-                ipServer.unwanted();
+                ensureIpServerUnwanted(ipServer);
                 return;
             }
         }
@@ -1775,9 +1792,7 @@ public class Tethering {
 
     void setUsbTethering(boolean enable, IIntResultListener listener) {
         mHandler.post(() -> {
-            try {
+            sendTetherResult(listener, setUsbTethering(enable));
-                listener.onResult(setUsbTethering(enable));
-            } catch (RemoteException e) { }
         });
     }
 
@@ -2904,6 +2919,9 @@ public class Tethering {
                 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);
             }
 
@@ -2918,7 +2936,19 @@ public class Tethering {
             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:
@@ -3014,11 +3044,18 @@ public class Tethering {
         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);
     }
@@ -3026,9 +3063,7 @@ public class Tethering {
     void setPreferTestNetworks(final boolean prefer, IIntResultListener listener) {
         mHandler.post(() -> {
             mUpstreamNetworkMonitor.setPreferTestNetworks(prefer);
-            try {
+            sendTetherResult(listener, TETHER_ERROR_NO_ERROR);
-                listener.onResult(TETHER_ERROR_NO_ERROR);
-            } catch (RemoteException e) { }
         });
     }
 

Tethering/tests/unit/src/com/android/networkstack/tethering/RequestTrackerTest.java

@@ -18,19 +18,22 @@ package com.android.networkstack.tethering;
 
 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;
 
@@ -39,13 +42,10 @@ import org.junit.runner.RunWith;
 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));
@@ -53,6 +53,7 @@ public class RequestTrackerTest {
 
     @Test
     public void testAddRequest_successResultAndBecomesNextPending() {
+        mRequestTracker = new RequestTracker(false);
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
 
         final AddResult result = mRequestTracker.addPendingRequest(request);
@@ -64,6 +65,7 @@ public class RequestTrackerTest {
 
     @Test
     public void testAddRequest_equalRequestExists_successResultAndBecomesNextPending() {
+        mRequestTracker = new RequestTracker(false);
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
         mRequestTracker.addPendingRequest(request);
 
@@ -77,6 +79,7 @@ public class RequestTrackerTest {
 
     @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");
@@ -94,7 +97,8 @@ public class RequestTrackerTest {
     }
 
     @Test
-    public void testAddConflictingRequest_returnsFailureConflictingPendingRequest() {
+    public void testAddRequest_conflictingPendingRequest_returnsFailureConflictingRequestRestart() {
+        mRequestTracker = new RequestTracker(false);
         final TetheringRequest request = new TetheringRequest.Builder(TETHERING_WIFI).build();
         final TetheringRequest conflictingRequest = new TetheringRequest.Builder(TETHERING_WIFI)
                 .setExemptFromEntitlementCheck(true).build();
@@ -102,13 +106,139 @@ public class RequestTrackerTest {
 
         final AddResult result = mRequestTracker.addPendingRequest(conflictingRequest);
 
-        assertThat(result).isEqualTo(AddResult.FAILURE_CONFLICTING_PENDING_REQUEST);
+        assertThat(result).isEqualTo(AddResult.FAILURE_DUPLICATE_REQUEST_RESTART);
         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");
@@ -127,6 +257,7 @@ public class RequestTrackerTest {
 
     @Test
     public void testRemoveAllPendingRequests_differentTypeExists_doesNotRemoveDifferentType() {
+        mRequestTracker = new RequestTracker(false);
         final TetheringRequest differentType = new TetheringRequest.Builder(TETHERING_USB).build();
         mRequestTracker.addPendingRequest(differentType);
 
@@ -136,4 +267,61 @@ public class RequestTrackerTest {
         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);
+    }
 }

Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java

@@ -50,6 +50,7 @@ import static android.net.TetheringManager.TETHERING_USB;
 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;
@@ -59,6 +60,7 @@ 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;
@@ -93,6 +95,7 @@ import static org.junit.Assert.assertNotNull;
 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;
@@ -197,6 +200,7 @@ import androidx.test.runner.AndroidJUnit4;
 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;
@@ -308,8 +312,7 @@ public class TetheringTest {
     @Mock private TetheringMetrics mTetheringMetrics;
     @Mock private PrivateAddressCoordinator.Dependencies mPrivateAddressCoordinatorDependencies;
 
-    private final MockIpServerDependencies mIpServerDependencies =
+    private MockIpServerDependencies mIpServerDependencies;
-            spy(new MockIpServerDependencies());
     private final MockTetheringDependencies mTetheringDependencies =
             new MockTetheringDependencies();
 
@@ -396,6 +399,9 @@ public class TetheringTest {
     }
 
     public class MockIpServerDependencies extends IpServer.Dependencies {
+
+        private int mOnDhcpServerCreatedResult = STATUS_SUCCESS;
+
         @Override
         public DadProxy getDadProxy(
                 Handler handler, InterfaceParams ifParams) {
@@ -437,7 +443,7 @@ public class TetheringTest {
                 DhcpServerCallbacks cb) {
             new Thread(() -> {
                 try {
-                    cb.onDhcpServerCreated(STATUS_SUCCESS, mDhcpServer);
+                    cb.onDhcpServerCreated(mOnDhcpServerCreatedResult, mDhcpServer);
                 } catch (RemoteException e) {
                     fail(e.getMessage());
                 }
@@ -448,6 +454,10 @@ public class TetheringTest {
                 IpNeighborMonitor.NeighborEventConsumer c) {
             return mIpNeighborMonitor;
         }
+
+        public void setOnDhcpServerCreatedResult(final int result) {
+            mOnDhcpServerCreatedResult = result;
+        }
     }
 
     public class MockTetheringDependencies extends TetheringDependencies {
@@ -708,6 +718,7 @@ public class TetheringTest {
 
         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.
@@ -2425,7 +2436,7 @@ public class TetheringTest {
 
     @Test
     public void testSoftApConfigInTetheringEventCallback() throws Exception {
-        assumeTrue(SdkLevel.isAtLeastV());
+        assumeTrue(isTetheringWithSoftApConfigEnabled());
         when(mContext.checkCallingOrSelfPermission(NETWORK_SETTINGS))
                 .thenReturn(PERMISSION_DENIED);
         when(mContext.checkCallingOrSelfPermission(NETWORK_STACK))
@@ -2482,14 +2493,12 @@ public class TetheringTest {
         // Enable wifi tethering
         mBinderCallingUid = TEST_CALLER_UID;
         mTethering.startTethering(tetheringRequest, TEST_CALLER_PKG, null);
+        mLooper.dispatchAll();
         mTethering.interfaceStatusChanged(TEST_WLAN_IFNAME, true);
         mLooper.dispatchAll();
-        if (SdkLevel.isAtLeastB()) {
+        // Netd "up" event should not trigger a state change callback in B+.
-            // Starting in B, ignore the interfaceStatusChanged
+        callback.assertNoStateChangeCallback();
-            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);
@@ -2507,20 +2516,15 @@ public class TetheringTest {
         callback.expectOffloadStatusChanged(TETHER_HARDWARE_OFFLOAD_STARTED);
 
         // Disable wifi tethering
-        mLooper.dispatchAll();
         mTethering.stopTethering(TETHERING_WIFI);
-        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED);
+        mLooper.dispatchAll();
-        if (isAtLeastT()) {
+        sendWifiApStateChanged(WIFI_AP_STATE_DISABLED, TEST_WLAN_IFNAME,
-            // 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[] {wifiIfaceWithConfig},
+        assertArrayEquals(new TetheringInterface[] {wifiIfaceWithoutConfig},
                 settingsCallback.pollTetherStatesChanged().availableList);
         mLooper.dispatchAll();
         callback.expectUpstreamChanged(NULL_NETWORK);
@@ -2528,6 +2532,253 @@ public class TetheringTest {
         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 testReportFailCallbackIfOffloadNotSupported() throws Exception {
         initTetheringOnTestThread();
@@ -2794,7 +3045,8 @@ public class TetheringTest {
     }
 
     @Test
-    public void testMultipleStartTethering() throws Exception {
+    public void testMultipleStartTetheringLegacy() throws Exception {
+        assumeFalse(isTetheringWithSoftApConfigEnabled());
         initTetheringOnTestThread();
         final LinkAddress serverLinkAddr = new LinkAddress("192.168.20.1/24");
         final LinkAddress clientLinkAddr = new LinkAddress("192.168.20.42/24");
@@ -3575,6 +3827,7 @@ public class TetheringTest {
     @Test
     public void testStartBluetoothTetheringFailsWhenTheresAnExistingRequestWaitingForPanService()
             throws Exception {
+        assumeFalse(isTetheringWithSoftApConfigEnabled());
         initTetheringOnTestThread();
 
         mockBluetoothSettings(true /* bluetoothOn */, true /* tetheringOn */);

tests/cts/tethering/src/android/tethering/cts/TetheringManagerTest.java

@@ -32,6 +32,7 @@ import static android.net.TetheringManager.TETHERING_USB;
 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;
@@ -234,6 +235,30 @@ public class TetheringManagerTest {
 
     }
 
+    @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()) {
@@ -380,17 +405,20 @@ public class TetheringManagerTest {
             tetherEventCallback.assumeWifiTetheringSupported(mContext);
             tetherEventCallback.expectNoTetheringActive();
 
-            SoftApConfiguration softApConfig = createSoftApConfiguration("SSID");
+            SoftApConfiguration softApConfig = isTetheringWithSoftApConfigEnabled()
+                    ? createSoftApConfiguration("SSID") : null;
             final TetheringInterface tetheredIface =
                     mCtsTetheringUtils.startWifiTethering(tetherEventCallback, softApConfig);
 
             assertNotNull(tetheredIface);
-            assertEquals(softApConfig, tetheredIface.getSoftApConfiguration());
+            if  (isTetheringWithSoftApConfigEnabled()) {
-            final String wifiTetheringIface = tetheredIface.getInterface();
+                assertEquals(softApConfig, tetheredIface.getSoftApConfiguration());
+            }
 
             mCtsTetheringUtils.stopWifiTethering(tetherEventCallback);
 
             if (!SdkLevel.isAtLeastB()) {
+                final String wifiTetheringIface = tetheredIface.getInterface();
                 try {
                     final int ret = runAsShell(TETHER_PRIVILEGED,
                             () -> mTM.tether(wifiTetheringIface));