[NAN] Separate ATTACH from IDENTITY_CHANGE callbacks.

Provide separate mechanism to attach with a request for identity
change listener.

(cherry-pick of commit 78e33f277eff5183f4525ce2a699acf2ad848177)

Bug: 31470256
Test: unit tests & integration (sl4a) tests.
Change-Id: I26b3bf4e904f3c3822578185fa55e2de5e63b71b

5 files changed, 113 insertions, 166 deletions

diff --git a/wifi/java/android/net/wifi/nan/ConfigRequest.java b/wifi/java/android/net/wifi/nan/ConfigRequest.java
index 3501ae84283c..bcd79322e563 100644
--- a/wifi/java/android/net/wifi/nan/ConfigRequest.java
+++ b/wifi/java/android/net/wifi/nan/ConfigRequest.java
@@ -16,87 +16,65 @@
 
 package android.net.wifi.nan;
 
-import android.annotation.SystemApi;
 import android.os.Parcel;
 import android.os.Parcelable;
 
 /**
  * Defines a request object to configure a Wi-Fi NAN network. Built using
  * {@link ConfigRequest.Builder}. Configuration is requested using
- * {@link WifiNanManager#attach(android.os.Handler, WifiNanEventCallback)}.
+ * {@link WifiNanManager#attach(android.os.Handler, WifiNanAttachCallback)}.
  * Note that the actual achieved configuration may be different from the
  * requested configuration - since different applications may request different
  * configurations.
  *
- * @hide PROPOSED_NAN_API
+ * @hide
  */
 public final class ConfigRequest implements Parcelable {
     /**
      * Lower range of possible cluster ID.
-     *
-     * @hide
      */
     public static final int CLUSTER_ID_MIN = 0;
 
     /**
      * Upper range of possible cluster ID.
-     *
-     * @hide
      */
     public static final int CLUSTER_ID_MAX = 0xFFFF;
 
     /**
      * Indicates whether 5G band support is requested.
-     *
-     * @hide
      */
     public final boolean mSupport5gBand;
 
     /**
      * Specifies the desired master preference.
-     *
-     * @hide
      */
     public final int mMasterPreference;
 
     /**
      * Specifies the desired lower range of the cluster ID. Must be lower then
      * {@link ConfigRequest#mClusterHigh}.
-     *
-     * @hide
      */
     public final int mClusterLow;
 
     /**
      * Specifies the desired higher range of the cluster ID. Must be higher then
      * {@link ConfigRequest#mClusterLow}.
-     *
-     * @hide
      */
     public final int mClusterHigh;
 
-    /**
-     * Indicates whether we want to get callbacks when our identity is changed.
-     *
-     * @hide
-     */
-    public final boolean mEnableIdentityChangeCallback;
-
     private ConfigRequest(boolean support5gBand, int masterPreference, int clusterLow,
-            int clusterHigh, boolean enableIdentityChangeCallback) {
+            int clusterHigh) {
         mSupport5gBand = support5gBand;
         mMasterPreference = masterPreference;
         mClusterLow = clusterLow;
         mClusterHigh = clusterHigh;
-        mEnableIdentityChangeCallback = enableIdentityChangeCallback;
     }
 
     @Override
     public String toString() {
         return "ConfigRequest [mSupport5gBand=" + mSupport5gBand + ", mMasterPreference="
                 + mMasterPreference + ", mClusterLow=" + mClusterLow + ", mClusterHigh="
-                + mClusterHigh + ", mEnableIdentityChangeCallback=" + mEnableIdentityChangeCallback
-                + "]";
+                + mClusterHigh + "]";
     }
 
     @Override
@@ -110,7 +88,6 @@ public final class ConfigRequest implements Parcelable {
         dest.writeInt(mMasterPreference);
         dest.writeInt(mClusterLow);
         dest.writeInt(mClusterHigh);
-        dest.writeInt(mEnableIdentityChangeCallback ? 1 : 0);
     }
 
     public static final Creator<ConfigRequest> CREATOR = new Creator<ConfigRequest>() {
@@ -125,9 +102,7 @@ public final class ConfigRequest implements Parcelable {
             int masterPreference = in.readInt();
             int clusterLow = in.readInt();
             int clusterHigh = in.readInt();
-            boolean enableIdentityChangeCallback = in.readInt() != 0;
-            return new ConfigRequest(support5gBand, masterPreference, clusterLow, clusterHigh,
-                    enableIdentityChangeCallback);
+            return new ConfigRequest(support5gBand, masterPreference, clusterLow, clusterHigh);
         }
     };
 
@@ -144,43 +119,15 @@ public final class ConfigRequest implements Parcelable {
         ConfigRequest lhs = (ConfigRequest) o;
 
         return mSupport5gBand == lhs.mSupport5gBand && mMasterPreference == lhs.mMasterPreference
-                && mClusterLow == lhs.mClusterLow && mClusterHigh == lhs.mClusterHigh
-                && mEnableIdentityChangeCallback == lhs.mEnableIdentityChangeCallback;
-    }
-
-    /**
-     * Checks for equality of two configuration - but only considering their
-     * on-the-air NAN configuration impact.
-     *
-     * @param o Object to compare to.
-     * @return true if configuration objects have the same on-the-air
-     *         configuration, false otherwise.
-     *
-     * @hide
-     */
-    public boolean equalsOnTheAir(Object o) {
-        if (this == o) {
-            return true;
-        }
-
-        if (!(o instanceof ConfigRequest)) {
-            return false;
-        }
-
-        ConfigRequest lhs = (ConfigRequest) o;
-
-        return mSupport5gBand == lhs.mSupport5gBand && mMasterPreference == lhs.mMasterPreference
                 && mClusterLow == lhs.mClusterLow && mClusterHigh == lhs.mClusterHigh;
     }
 
     /**
-     * Checks whether the configuration's settings which impact on-air behavior are non-default.
-     *
-     * @return true if any of the on-air-impacting settings are non-default.
+     * Checks whether the configuration's settings are non-default.
      *
-     * @hide
+     * @return true if any of the settings are non-default.
      */
-    public boolean isNonDefaultOnTheAir() {
+    public boolean isNonDefault() {
         return mSupport5gBand || mMasterPreference != 0 || mClusterLow != CLUSTER_ID_MIN
                 || mClusterHigh != CLUSTER_ID_MAX;
     }
@@ -193,7 +140,6 @@ public final class ConfigRequest implements Parcelable {
         result = 31 * result + mMasterPreference;
         result = 31 * result + mClusterLow;
         result = 31 * result + mClusterHigh;
-        result = 31 * result + (mEnableIdentityChangeCallback ? 1 : 0);
 
         return result;
     }
@@ -201,8 +147,6 @@ public final class ConfigRequest implements Parcelable {
     /**
      * Verifies that the contents of the ConfigRequest are valid. Otherwise
      * throws an IllegalArgumentException.
-     *
-     * @hide
      */
     public void validate() throws IllegalArgumentException {
         if (mMasterPreference < 0) {
@@ -239,7 +183,6 @@ public final class ConfigRequest implements Parcelable {
         private int mMasterPreference = 0;
         private int mClusterLow = CLUSTER_ID_MIN;
         private int mClusterHigh = CLUSTER_ID_MAX;
-        private boolean mEnableIdentityChangeCallback = false;
 
         /**
          * Specify whether 5G band support is required in this request. Disabled by default.
@@ -248,8 +191,6 @@ public final class ConfigRequest implements Parcelable {
          *
          * @return The builder to facilitate chaining
          *         {@code builder.setXXX(..).setXXX(..)}.
-         *
-         * @hide PROPOSED_NAN_SYSTEM_API
          */
         public Builder setSupport5gBand(boolean support5gBand) {
             mSupport5gBand = support5gBand;
@@ -264,8 +205,6 @@ public final class ConfigRequest implements Parcelable {
          *
          * @return The builder to facilitate chaining
          *         {@code builder.setXXX(..).setXXX(..)}.
-         *
-         * @hide PROPOSED_NAN_SYSTEM_API
          */
         public Builder setMasterPreference(int masterPreference) {
             if (masterPreference < 0) {
@@ -293,8 +232,6 @@ public final class ConfigRequest implements Parcelable {
          *
          * @return The builder to facilitate chaining
          *         {@code builder.setClusterLow(..).setClusterHigh(..)}.
-         *
-         * @hide PROPOSED_NAN_SYSTEM_API
          */
         public Builder setClusterLow(int clusterLow) {
             if (clusterLow < CLUSTER_ID_MIN) {
@@ -320,8 +257,6 @@ public final class ConfigRequest implements Parcelable {
          *
          * @return The builder to facilitate chaining
          *         {@code builder.setClusterLow(..).setClusterHigh(..)}.
-         *
-         * @hide PROPOSED_NAN_SYSTEM_API
          */
         public Builder setClusterHigh(int clusterHigh) {
             if (clusterHigh < CLUSTER_ID_MIN) {
@@ -336,27 +271,6 @@ public final class ConfigRequest implements Parcelable {
         }
 
         /**
-         * Indicate whether or not we want to enable the
-         * {@link WifiNanEventCallback#onIdentityChanged(byte[])} callback. A
-         * device identity is its Discovery MAC address which is randomized at regular intervals.
-         * An application may need to know the MAC address, e.g. when using OOB (out-of-band)
-         * discovery together with NAN connections.
-         * <p>
-         *     The callbacks are disabled by default since it may result in additional wake-ups
-         *     of the host -
-         *     increasing power.
-         *
-         * @param enableIdentityChangeCallback Enable the callback informing
-         *            listener when identity is changed.
-         * @return The builder to facilitate chaining
-         *         {@code builder.setXXX(..).setXXX(..)}.
-         */
-        public Builder setEnableIdentityChangeCallback(boolean enableIdentityChangeCallback) {
-            mEnableIdentityChangeCallback = enableIdentityChangeCallback;
-            return this;
-        }
-
-        /**
          * Build {@link ConfigRequest} given the current requests made on the
          * builder.
          */
@@ -366,8 +280,7 @@ public final class ConfigRequest implements Parcelable {
                         "Invalid argument combination - must have Cluster Low <= Cluster High");
             }
 
-            return new ConfigRequest(mSupport5gBand, mMasterPreference, mClusterLow, mClusterHigh,
-                    mEnableIdentityChangeCallback);
+            return new ConfigRequest(mSupport5gBand, mMasterPreference, mClusterLow, mClusterHigh);
         }
     }
 }
diff --git a/wifi/java/android/net/wifi/nan/IWifiNanManager.aidl b/wifi/java/android/net/wifi/nan/IWifiNanManager.aidl
index 4e1f607e0902..006097df08be 100644
--- a/wifi/java/android/net/wifi/nan/IWifiNanManager.aidl
+++ b/wifi/java/android/net/wifi/nan/IWifiNanManager.aidl
@@ -39,7 +39,7 @@ interface IWifiNanManager
 
     // client API
     void connect(in IBinder binder, in String callingPackage, in IWifiNanEventCallback callback,
-            in ConfigRequest configRequest);
+            in ConfigRequest configRequest, boolean notifyOnIdentityChanged);
     void disconnect(int clientId, in IBinder binder);
 
     void publish(int clientId, in PublishConfig publishConfig,
diff --git a/wifi/java/android/net/wifi/nan/WifiNanEventCallback.java b/wifi/java/android/net/wifi/nan/WifiNanAttachCallback.java
index 9c3acefb690e..aa67823823a9 100644
--- a/wifi/java/android/net/wifi/nan/WifiNanEventCallback.java
+++ b/wifi/java/android/net/wifi/nan/WifiNanAttachCallback.java
@@ -22,14 +22,14 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 
 /**
- * Base class for NAN events callbacks. Should be extended by applications and set when calling
- * {@link WifiNanManager#attach(android.os.Handler, WifiNanEventCallback)}. These are callbacks
+ * Base class for NAN attach callbacks. Should be extended by applications and set when calling
+ * {@link WifiNanManager#attach(android.os.Handler, WifiNanAttachCallback)}. These are callbacks
  * applying to the NAN connection as a whole - not to specific publish or subscribe sessions -
  * for that see {@link WifiNanDiscoverySessionCallback}.
  *
  * @hide PROPOSED_NAN_API
  */
-public class WifiNanEventCallback {
+public class WifiNanAttachCallback {
     /** @hide */
     @IntDef({
             REASON_INVALID_ARGS, REASON_ALREADY_CONNECTED_INCOMPAT_CONFIG, REASON_OTHER
@@ -40,27 +40,27 @@ public class WifiNanEventCallback {
 
     /**
      * Indicates invalid argument in the requested operation. Failure reason flag for
-     * {@link WifiNanEventCallback#onAttachFailed(int)}.
+     * {@link WifiNanAttachCallback#onAttachFailed(int)}.
      */
     public static final int REASON_INVALID_ARGS = 1000;
 
     /**
      * Indicates that a {@link ConfigRequest} passed in
-     * {@link WifiNanManager#attach(android.os.Handler, ConfigRequest, WifiNanEventCallback)}
+     * {@code WifiNanManager#attach(android.os.Handler, ConfigRequest, WifiNanAttachCallback)}
      * couldn't be applied since other connections already exist with an incompatible
-     * configurations. Failure reason flag for {@link WifiNanEventCallback#onAttachFailed(int)}.
+     * configurations. Failure reason flag for {@link WifiNanAttachCallback#onAttachFailed(int)}.
      */
     public static final int REASON_ALREADY_CONNECTED_INCOMPAT_CONFIG = 1001;
 
     /**
      * Indicates an unspecified error occurred during the operation. Failure reason flag for
-     * {@link WifiNanEventCallback#onAttachFailed(int)}.
+     * {@link WifiNanAttachCallback#onAttachFailed(int)}.
      */
     public static final int REASON_OTHER = 1002;
 
     /**
      * Called when NAN attach operation
-     * {@link WifiNanManager#attach(android.os.Handler, WifiNanEventCallback)}
+     * {@link WifiNanManager#attach(android.os.Handler, WifiNanAttachCallback)}
      * is completed and that we can now start discovery sessions or connections.
      *
      * @param session The NAN object on which we can execute further NAN operations - e.g.
@@ -72,7 +72,7 @@ public class WifiNanEventCallback {
 
     /**
      * Called when NAN attach operation
-     * {@link WifiNanManager#attach(android.os.Handler, WifiNanEventCallback)} failed.
+     * {@link WifiNanManager#attach(android.os.Handler, WifiNanAttachCallback)} failed.
      *
      * @param reason Failure reason code, see
      *            {@code WifiNanEventCallback.REASON_*}.
@@ -80,29 +80,4 @@ public class WifiNanEventCallback {
     public void onAttachFailed(@EventReasonCodes int reason) {
         /* empty */
     }
-
-    /**
-     * Called when NAN identity (the MAC address representing our NAN discovery interface) has
-     * changed. Change may be due to device joining a cluster, starting a cluster, or discovery
-     * interface change (addresses are randomized at regular intervals). The implication is that
-     * peers you've been communicating with may no longer recognize you and you need to
-     * re-establish your identity - e.g. by starting a discovery session. This actual MAC address
-     * of the interface may also be useful if the application uses alternative (non-NAN)
-     * discovery but needs to set up a NAN connection. The provided NAN discovery interface MAC
-     * address can then be used in
-     * {@link WifiNanSession#createNetworkSpecifier(int, byte[], byte[])}.
-     * <p>
-     *     This callback is only called if the NAN connection enables it using
-     *     {@link ConfigRequest.Builder#setEnableIdentityChangeCallback(boolean)} in
-     *     {@link WifiNanManager#attach(android.os.Handler, ConfigRequest, WifiNanEventCallback)}
-     *     . It is disabled by default since it may result in additional wake-ups of the host -
-     *     increasing power.
-     *
-     * @param mac The MAC address of the NAN discovery interface. The application must have the
-     * {@link android.Manifest.permission#ACCESS_COARSE_LOCATION} to get the actual MAC address,
-     *            otherwise all 0's will be provided.
-     */
-    public void onIdentityChanged(byte[] mac) {
-        /* empty */
-    }
 }
diff --git a/wifi/java/android/net/wifi/nan/WifiNanIdentityChangedListener.java b/wifi/java/android/net/wifi/nan/WifiNanIdentityChangedListener.java
new file mode 100644
index 000000000000..7cb928fd578c
--- /dev/null
+++ b/wifi/java/android/net/wifi/nan/WifiNanIdentityChangedListener.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.wifi.nan;
+
+/**
+ * Base class for a listener which is called with the MAC address of the NAN interface whenever
+ * it is changed. Change may be due to device joining a cluster, starting a cluster, or discovery
+ * interface change (addresses are randomized at regular intervals). The implication is that
+ * peers you've been communicating with may no longer recognize you and you need to re-establish
+ * your identity - e.g. by starting a discovery session. This actual MAC address of the
+ * interface may also be useful if the application uses alternative (non-NAN) discovery but needs
+ * to set up a NAN connection. The provided NAN discovery interface MAC address can then be used
+ * in {@link WifiNanSession#createNetworkSpecifier(int, byte[], byte[])}.
+ *
+ * @hide PROPOSED_NAN_API
+ */
+public class WifiNanIdentityChangedListener {
+    /**
+     * @param mac The MAC address of the NAN discovery interface. The application must have the
+     * {@link android.Manifest.permission#ACCESS_COARSE_LOCATION} to get the actual MAC address,
+     *            otherwise all 0's will be provided.
+     */
+    public void onIdentityChanged(byte[] mac) {
+        /* empty */
+    }
+}
diff --git a/wifi/java/android/net/wifi/nan/WifiNanManager.java b/wifi/java/android/net/wifi/nan/WifiNanManager.java
index 79bf946ba731..0fb604768c50 100644
--- a/wifi/java/android/net/wifi/nan/WifiNanManager.java
+++ b/wifi/java/android/net/wifi/nan/WifiNanManager.java
@@ -56,11 +56,11 @@ import java.util.Arrays;
  * The class provides access to:
  * <ul>
  * <li>Initialize a NAN cluster (peer-to-peer synchronization). Refer to
- * {@link #attach(Handler, WifiNanEventCallback)}. <li>Create discovery sessions (publish or
- * subscribe sessions). Refer to
+ * {@link #attach(Handler, WifiNanAttachCallback)}.
+ * <li>Create discovery sessions (publish or subscribe sessions). Refer to
  * {@link WifiNanSession#publish(PublishConfig, WifiNanDiscoverySessionCallback)} and
- * {@link WifiNanSession#subscribe(SubscribeConfig, WifiNanDiscoverySessionCallback)}. <li>Create
- * a NAN network specifier to be used with
+ * {@link WifiNanSession#subscribe(SubscribeConfig, WifiNanDiscoverySessionCallback)}.
+ * <li>Create a NAN network specifier to be used with
  * {@link ConnectivityManager#requestNetwork(NetworkRequest, ConnectivityManager.NetworkCallback)}
  * to set-up a NAN connection with a peer. Refer to
  * {@link WifiNanDiscoveryBaseSession#createNetworkSpecifier(int, int, byte[])} and
@@ -73,13 +73,13 @@ import java.util.Arrays;
  *     Note that this broadcast is not sticky - you should register for it and then check the
  *     above API to avoid a race condition.
  * <p>
- *     An application must use {@link #attach(Handler, WifiNanEventCallback)} to initialize a NAN
+ *     An application must use {@link #attach(Handler, WifiNanAttachCallback)} to initialize a NAN
  *     cluster - before making any other NAN operation. NAN cluster membership is a device-wide
  *     operation - the API guarantees that the device is in a cluster or joins a NAN cluster (or
  *     starts one if none can be found). Information about attach success (or failure) are
- *     returned in callbacks of {@link WifiNanEventCallback}. Proceed with NAN discovery or
+ *     returned in callbacks of {@link WifiNanAttachCallback}. Proceed with NAN discovery or
  *     connection setup only after receiving confirmation that NAN attach succeeded -
- *     {@link WifiNanEventCallback#onAttached(WifiNanSession)}. When an application is
+ *     {@link WifiNanAttachCallback#onAttached(WifiNanSession)}. When an application is
  *     finished using NAN it <b>must</b> use the {@link WifiNanSession#destroy()} API
  *     to indicate to the NAN service that the device may detach from the NAN cluster. The
  *     device will actually disable NAN once the last application detaches.
@@ -319,50 +319,67 @@ public class WifiNanManager {
     }
 
     /**
-     * Attach to the Wi-Fi NAN service - enabling the application to create discovery session or
-     * create connection to peers. The device will attach to an existing cluster if it can find
+     * Attach to the Wi-Fi NAN service - enabling the application to create discovery sessions or
+     * create connections to peers. The device will attach to an existing cluster if it can find
      * one or create a new cluster (if it is the first to enable NAN in its vicinity). Results
-     * (e.g. successful attach to a cluster) are provided to the {@code callback} object.
+     * (e.g. successful attach to a cluster) are provided to the {@code attachCallback} object.
      * An application <b>must</b> call {@link WifiNanSession#destroy()} when done with the
      * Wi-Fi NAN object.
      * <p>
      * Note: a NAN cluster is a shared resource - if the device is already attached to a cluster
-     * than this function will simply indicate success immediately.
+     * then this function will simply indicate success immediately using the same {@code
+     * attachCallback}.
      *
      * @param handler The Handler on whose thread to execute all callbacks related to the
      *            attach request - including all sessions opened as part of this
      *            attach. If a null is provided then the application's main thread will be used.
-     * @param callback A callback extended from {@link WifiNanEventCallback}.
+     * @param attachCallback A callback for attach events, extended from
+     * {@link WifiNanAttachCallback}.
      */
-    public void attach(@Nullable Handler handler, @NonNull WifiNanEventCallback callback) {
-        attach(handler, null, callback);
+    public void attach(@Nullable Handler handler, @NonNull WifiNanAttachCallback attachCallback) {
+        attach(handler, null, attachCallback, null);
     }
 
     /**
-     * Attach to the Wi-Fi NAN service - enabling the application to create discovery session or
-     * create connection to peers. The device will attach to an existing cluster if it can find
+     * Attach to the Wi-Fi NAN service - enabling the application to create discovery sessions or
+     * create connections to peers. The device will attach to an existing cluster if it can find
      * one or create a new cluster (if it is the first to enable NAN in its vicinity). Results
-     * (e.g. successful attach to a cluster) are provided to the {@code callback} object.
+     * (e.g. successful attach to a cluster) are provided to the {@code attachCallback} object.
      * An application <b>must</b> call {@link WifiNanSession#destroy()} when done with the
-     * Wi-Fi NAN object. Allows requesting a specific configuration using
-     * {@link ConfigRequest}. If not necessary (default configuration should usually work) use
-     * the {@link #attach(Handler, WifiNanEventCallback)} method instead.
+     * Wi-Fi NAN object.
      * <p>
      * Note: a NAN cluster is a shared resource - if the device is already attached to a cluster
-     * than this function will simply indicate success immediately.
+     * then this function will simply indicate success immediately using the same {@code
+     * attachCallback}.
+     * <p>
+     * This version of the API attaches a listener to receive the MAC address of the NAN interface
+     * on startup and whenever it is updated (it is randomized at regular intervals for privacy).
+     * The application must have the {@link android.Manifest.permission#ACCESS_COARSE_LOCATION}
+     * permission to execute this attach request. Otherwise, use the
+     * {@link #attach(Handler, WifiNanAttachCallback)} version. Note that aside from permission
+     * requirements this listener will wake up the host at regular intervals causing higher power
+     * consumption, do not use it unless the information is necessary (e.g. for OOB discovery).
      *
      * @param handler The Handler on whose thread to execute all callbacks related to the
      *            attach request - including all sessions opened as part of this
      *            attach. If a null is provided then the application's main thread will be used.
-     * @param configRequest The requested NAN configuration.
-     * @param callback A callback extended from {@link WifiNanEventCallback}.
+     * @param attachCallback A callback for attach events, extended from
+     * {@link WifiNanAttachCallback}.
+     * @param identityChangedListener A listener for changed identity.
      */
-    public void attach(@Nullable Handler handler, @Nullable ConfigRequest configRequest,
-            @NonNull WifiNanEventCallback callback) {
+    public void attach(@Nullable Handler handler, @NonNull WifiNanAttachCallback attachCallback,
+            @NonNull WifiNanIdentityChangedListener identityChangedListener) {
+        attach(handler, null, attachCallback, identityChangedListener);
+    }
+
+    /** @hide */
+    public void attach(Handler handler, ConfigRequest configRequest,
+            WifiNanAttachCallback attachCallback,
+            WifiNanIdentityChangedListener identityChangedListener) {
         if (VDBG) {
-            Log.v(TAG,
-                    "attach(): handler=" + handler + ", callback=" + callback + ", configRequest="
-                            + configRequest);
+            Log.v(TAG, "attach(): handler=" + handler + ", callback=" + attachCallback
+                    + ", configRequest=" + configRequest + ", identityChangedListener="
+                    + identityChangedListener);
         }
 
         synchronized (mLock) {
@@ -371,8 +388,9 @@ public class WifiNanManager {
             try {
                 Binder binder = new Binder();
                 mService.connect(binder, mContext.getOpPackageName(),
-                        new WifiNanEventCallbackProxy(this, looper, binder, callback),
-                        configRequest);
+                        new WifiNanEventCallbackProxy(this, looper, binder, attachCallback,
+                                identityChangedListener), configRequest,
+                        identityChangedListener != null);
             } catch (RemoteException e) {
                 throw e.rethrowFromSystemServer();
             }
@@ -648,13 +666,14 @@ public class WifiNanManager {
         }
 
         /**
-         * Constructs a {@link WifiNanEventCallback} using the specified looper.
+         * Constructs a {@link WifiNanAttachCallback} using the specified looper.
          * All callbacks will delivered on the thread of the specified looper.
          *
          * @param looper The looper on which to execute the callbacks.
          */
         WifiNanEventCallbackProxy(WifiNanManager mgr, Looper looper, Binder binder,
-                final WifiNanEventCallback originalCallback) {
+                final WifiNanAttachCallback attachCallback,
+                final WifiNanIdentityChangedListener identityChangedListener) {
             mNanManager = new WeakReference<>(mgr);
             mLooper = looper;
             mBinder = binder;
@@ -675,15 +694,15 @@ public class WifiNanManager {
 
                     switch (msg.what) {
                         case CALLBACK_CONNECT_SUCCESS:
-                            originalCallback.onAttached(
+                            attachCallback.onAttached(
                                     new WifiNanSession(mgr, mBinder, mLooper, msg.arg1));
                             break;
                         case CALLBACK_CONNECT_FAIL:
                             mNanManager.clear();
-                            originalCallback.onAttachFailed(msg.arg1);
+                            attachCallback.onAttachFailed(msg.arg1);
                             break;
                         case CALLBACK_IDENTITY_CHANGED:
-                            originalCallback.onIdentityChanged((byte[]) msg.obj);
+                            identityChangedListener.onIdentityChanged((byte[]) msg.obj);
                             break;
                         case CALLBACK_RANGING_SUCCESS: {
                             RttManager.RttListener listener = getAndRemoveRangingListener(msg.arg1);