Add USD characterstics

Flag: android.net.wifi.flags.usd
Bug: 340878198
Test: atest FrameworksWifiApiTests
Change-Id: Ia4395af58ae5042279b6316fc4c437a96a4c3d6a

6 files changed, 223 insertions, 0 deletions

diff --git a/framework/aidl-export/android/net/wifi/usd/Characteristics.aidl b/framework/aidl-export/android/net/wifi/usd/Characteristics.aidl
new file mode 100644
index 0000000000..818426bda2
--- /dev/null
+++ b/framework/aidl-export/android/net/wifi/usd/Characteristics.aidl
@@ -0,0 +1,19 @@
+/**
+ * Copyright (c) 2024, 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.usd;
+
+parcelable Characteristics;
diff --git a/framework/api/system-current.txt b/framework/api/system-current.txt
index 7ea49964ff..e37b7f8404 100644
--- a/framework/api/system-current.txt
+++ b/framework/api/system-current.txt
@@ -1847,6 +1847,17 @@ package android.net.wifi.twt {
 
 package android.net.wifi.usd {
 
+  @FlaggedApi("android.net.wifi.flags.usd") public final class Characteristics implements android.os.Parcelable {
+    method public int describeContents();
+    method public int getMaxMatchFilterLength();
+    method public int getMaxNumberOfPublishSessions();
+    method public int getMaxNumberOfSubscribeSessions();
+    method public int getMaxServiceNameLength();
+    method public int getMaxServiceSpecificInfoLength();
+    method public void writeToParcel(@NonNull android.os.Parcel, int);
+    field @NonNull public static final android.os.Parcelable.Creator<android.net.wifi.usd.Characteristics> CREATOR;
+  }
+
   @FlaggedApi("android.net.wifi.flags.usd") public abstract class Config {
     method @NonNull public java.util.List<byte[]> getRxMatchFilter();
     method @NonNull public byte[] getServiceName();
@@ -1907,6 +1918,7 @@ package android.net.wifi.usd {
   }
 
   @FlaggedApi("android.net.wifi.flags.usd") public class UsdManager {
+    method @Nullable @RequiresPermission(android.Manifest.permission.MANAGE_WIFI_NETWORK_SELECTION) public android.net.wifi.usd.Characteristics getCharacteristics();
     method @RequiresPermission(android.Manifest.permission.MANAGE_WIFI_NETWORK_SELECTION) public boolean isPublisherAvailable();
     method @RequiresPermission(android.Manifest.permission.MANAGE_WIFI_NETWORK_SELECTION) public boolean isPublisherSupported();
     method @RequiresPermission(android.Manifest.permission.MANAGE_WIFI_NETWORK_SELECTION) public boolean isSubscriberAvailable();
diff --git a/framework/java/android/net/wifi/usd/Characteristics.java b/framework/java/android/net/wifi/usd/Characteristics.java
new file mode 100644
index 0000000000..3467eeeaab
--- /dev/null
+++ b/framework/java/android/net/wifi/usd/Characteristics.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2024 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.usd;
+
+import android.annotation.FlaggedApi;
+import android.annotation.SystemApi;
+import android.net.wifi.flags.Flags;
+import android.os.Bundle;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import androidx.annotation.NonNull;
+
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.function.Consumer;
+
+/**
+ * The characteristics of the USD implementation.
+ *
+ * @hide
+ */
+@SystemApi
+@FlaggedApi(Flags.FLAG_USD)
+public final class Characteristics implements Parcelable {
+    private final Bundle mCharacteristics;
+    /** @hide */
+    public static final String KEY_MAX_SERVICE_NAME_LENGTH = "key_max_service_name_length";
+    /** @hide */
+    public static final String KEY_MAX_SERVICE_SPECIFIC_INFO_LENGTH =
+            "key_max_service_specific_info_length";
+    /** @hide */
+    public static final String KEY_MAX_MATCH_FILTER_LENGTH = "key_max_match_filter_length";
+    /** @hide */
+    public static final String KEY_MAX_NUM_PUBLISH_SESSIONS = "key_max_num_publish_session";
+    /** @hide */
+    public static final String KEY_MAX_NUM_SUBSCRIBE_SESSIONS = "key_max_num_subscribe_session";
+
+
+    /** @hide : should not be created by apps */
+    public Characteristics(Bundle characteristics) {
+        mCharacteristics = characteristics;
+    }
+
+    private Characteristics(@NonNull Parcel in) {
+        mCharacteristics = in.readBundle(getClass().getClassLoader());
+    }
+
+    @NonNull
+    public static final Creator<Characteristics> CREATOR = new Creator<Characteristics>() {
+        @Override
+        public Characteristics createFromParcel(Parcel in) {
+            return new Characteristics(in);
+        }
+
+        @Override
+        public Characteristics[] newArray(int size) {
+            return new Characteristics[size];
+        }
+    };
+
+    /**
+     * Returns the maximum string length that can be used to specify a USD service name.
+     *
+     * @return A positive integer, maximum string length of USD service name.
+     */
+    public int getMaxServiceNameLength() {
+        return mCharacteristics.getInt(KEY_MAX_SERVICE_NAME_LENGTH);
+    }
+
+    /**
+     * Returns the maximum length of byte array that can be used to specify a service specific
+     * information field: the arbitrary load used in discovery or the message length of USD
+     * message exchange. Restricts the parameters of the
+     * {@link PublishConfig.Builder#setServiceSpecificInfo(byte[])},
+     * {@link SubscribeConfig.Builder#setServiceSpecificInfo(byte[])},
+     * {@link PublishSession#sendMessage(int, byte[], Executor, Consumer)}  and
+     * {@link SubscribeSession#sendMessage(int, byte[], Executor, Consumer)}
+     * variants.
+     *
+     * @return A positive integer, maximum length of byte array for USD messaging.
+     */
+    public int getMaxServiceSpecificInfoLength() {
+        return mCharacteristics.getInt(KEY_MAX_SERVICE_SPECIFIC_INFO_LENGTH);
+    }
+
+    /**
+     * Returns the maximum length of byte array that can be used to specify a USD match filter.
+     * Restricts the parameters of the
+     * {@link PublishConfig.Builder#setTxMatchFilter(List)},
+     * {@link PublishConfig.Builder#setRxMatchFilter(List)},
+     * {@link SubscribeConfig.Builder#setTxMatchFilter(List)} and
+     * {@link SubscribeConfig.Builder#setRxMatchFilter(List)}
+     *
+     * @return A positive integer, maximum length of byte array for USD discovery match filter.
+     */
+    public int getMaxMatchFilterLength() {
+        return mCharacteristics.getInt(KEY_MAX_MATCH_FILTER_LENGTH);
+    }
+
+    /**
+     * Returns the maximum number of publish sessions supported by USD
+     *
+     * @return A positive integer
+     */
+    public int getMaxNumberOfPublishSessions() {
+        return mCharacteristics.getInt(KEY_MAX_NUM_PUBLISH_SESSIONS);
+    }
+
+    /**
+     * Returns the maximum number of subscribe sessions supported by USD
+     *
+     * @return A positive integer
+     */
+    public int getMaxNumberOfSubscribeSessions() {
+        return mCharacteristics.getInt(KEY_MAX_NUM_SUBSCRIBE_SESSIONS);
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    /**
+     * Flatten this object in to a Parcel.
+     *
+     * @param dest  The Parcel in which the object should be written.
+     * @param flags Additional flags about how the object should be written.
+     *              May be 0 or {@link #PARCELABLE_WRITE_RETURN_VALUE}.
+     */
+    @Override
+    public void writeToParcel(@NonNull Parcel dest, int flags) {
+        dest.writeBundle(mCharacteristics);
+    }
+}
diff --git a/framework/java/android/net/wifi/usd/IUsdManager.aidl b/framework/java/android/net/wifi/usd/IUsdManager.aidl
index 4d0ed3da3e..625f9b805d 100644
--- a/framework/java/android/net/wifi/usd/IUsdManager.aidl
+++ b/framework/java/android/net/wifi/usd/IUsdManager.aidl
@@ -16,6 +16,7 @@
 
 package android.net.wifi.usd;
 
+import android.net.wifi.usd.Characteristics;
 import android.net.wifi.usd.IAvailabilityCallback;
 
 /**
@@ -30,4 +31,5 @@ interface IUsdManager {
     boolean isPublisherAvailable();
     void registerAvailabilityCallback(IAvailabilityCallback callback);
     void unregisterAvailabilityCallback(IAvailabilityCallback callback);
+    Characteristics getCharacteristics();
 }
diff --git a/framework/java/android/net/wifi/usd/UsdManager.java b/framework/java/android/net/wifi/usd/UsdManager.java
index bcb23a2d28..a2e4217376 100644
--- a/framework/java/android/net/wifi/usd/UsdManager.java
+++ b/framework/java/android/net/wifi/usd/UsdManager.java
@@ -21,6 +21,7 @@ import static android.Manifest.permission.MANAGE_WIFI_NETWORK_SELECTION;
 import android.annotation.CallbackExecutor;
 import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.RequiresApi;
 import android.annotation.RequiresPermission;
 import android.annotation.SystemApi;
@@ -255,4 +256,23 @@ public class UsdManager {
             }
         }
     }
+
+    /**
+     * Gets the characteristics of USD: a set of parameters which specify limitations on
+     * configurations, e.g. maximum service name length.
+     *
+     * @return An object specifying the configuration limitation of USD. Return {@code null} if
+     * USD feature is not supported.
+     */
+    @RequiresPermission(MANAGE_WIFI_NETWORK_SELECTION)
+    public @Nullable Characteristics getCharacteristics() {
+        if (!Environment.isSdkAtLeastB()) {
+            throw new UnsupportedOperationException();
+        }
+        try {
+            return mService.getCharacteristics();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
 }
diff --git a/service/java/com/android/server/wifi/usd/UsdServiceImpl.java b/service/java/com/android/server/wifi/usd/UsdServiceImpl.java
index 2bbaa5a536..e0d340045f 100644
--- a/service/java/com/android/server/wifi/usd/UsdServiceImpl.java
+++ b/service/java/com/android/server/wifi/usd/UsdServiceImpl.java
@@ -18,10 +18,12 @@ package com.android.server.wifi.usd;
 
 import android.annotation.NonNull;
 import android.content.Context;
+import android.net.wifi.usd.Characteristics;
 import android.net.wifi.usd.IAvailabilityCallback;
 import android.net.wifi.usd.IUsdManager;
 import android.net.wifi.usd.UsdManager;
 import android.os.Binder;
+import android.os.Bundle;
 import android.util.Log;
 
 import com.android.server.wifi.RunnerHandler;
@@ -146,4 +148,23 @@ public class UsdServiceImpl extends IUsdManager.Stub {
             throw new SecurityException("App not allowed to use USD (uid = " + uid + ")");
         }
     }
+
+    /**
+     * See {@link UsdManager#getCharacteristics()}
+     */
+    @Override
+    public Characteristics getCharacteristics() {
+        int uid = getMockableCallingUid();
+        if (!mWifiPermissionsUtil.checkManageWifiNetworkSelectionPermission(uid)) {
+            throw new SecurityException("App not allowed to use USD (uid = " + uid + ")");
+        }
+
+        Bundle bundle = new Bundle();
+        bundle.putInt(Characteristics.KEY_MAX_NUM_SUBSCRIBE_SESSIONS, 0);
+        bundle.putInt(Characteristics.KEY_MAX_NUM_SUBSCRIBE_SESSIONS, 0);
+        bundle.putInt(Characteristics.KEY_MAX_SERVICE_SPECIFIC_INFO_LENGTH, 0);
+        bundle.putInt(Characteristics.KEY_MAX_MATCH_FILTER_LENGTH, 0);
+        bundle.putInt(Characteristics.KEY_MAX_SERVICE_NAME_LENGTH, 0);
+        return new Characteristics(bundle);
+    }
 }