framework/java/android/bluetooth/BluetoothServerSocket.java - platform/packages/modules/Bluetooth - Git at Google

 /*
  * Copyright (C) 2009 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.bluetooth;

 import android.annotation.NonNull;
 import android.annotation.RequiresNoPermission;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.os.ParcelUuid;
 import android.util.Log;

 import java.io.Closeable;
 import java.io.IOException;

 /**
  * A listening Bluetooth socket.
  *
  * <p>The interface for Bluetooth Sockets is similar to that of TCP sockets: {@link java.net.Socket}
  * and {@link java.net.ServerSocket}. On the server side, use a {@link BluetoothServerSocket} to
  * create a listening server socket. When a connection is accepted by the {@link
  * BluetoothServerSocket}, it will return a new {@link BluetoothSocket} to manage the connection. On
  * the client side, use a single {@link BluetoothSocket} to both initiate an outgoing connection and
  * to manage the connection.
  *
  * <p>For Bluetooth BR/EDR, the most common type of socket is RFCOMM, which is the type supported by
  * the Android APIs. RFCOMM is a connection-oriented, streaming transport over Bluetooth BR/EDR. It
  * is also known as the Serial Port Profile (SPP). To create a listening {@link
  * BluetoothServerSocket} that's ready for incoming Bluetooth BR/EDR connections, use {@link
  * BluetoothAdapter#listenUsingRfcommWithServiceRecord
  * BluetoothAdapter.listenUsingRfcommWithServiceRecord()}.
  *
  * <p>For Bluetooth LE, the socket uses LE Connection-oriented Channel (CoC). LE CoC is a
  * connection-oriented, streaming transport over Bluetooth LE and has a credit-based flow control.
  * Correspondingly, use {@link BluetoothAdapter#listenUsingL2capChannel
  * BluetoothAdapter.listenUsingL2capChannel()} to create a listening {@link BluetoothServerSocket}
  * that's ready for incoming Bluetooth LE CoC connections. For LE CoC, you can use {@link #getPsm()}
  * to get the protocol/service multiplexer (PSM) value that the peer needs to use to connect to your
  * socket.
  *
  * <p>After the listening {@link BluetoothServerSocket} is created, call {@link #accept()} to listen
  * for incoming connection requests. This call will block until a connection is established, at
  * which point, it will return a {@link BluetoothSocket} to manage the connection. Once the {@link
  * BluetoothSocket} is acquired, it's a good idea to call {@link #close()} on the {@link
  * BluetoothServerSocket} when it's no longer needed for accepting connections. Closing the {@link
  * BluetoothServerSocket} will <em>not</em> close the returned {@link BluetoothSocket}.
  *
  * <p>{@link BluetoothServerSocket} is thread safe. In particular, {@link #close} will always
  * immediately abort ongoing operations and close the server socket.
  *
  * <p><div class="special reference">
  *
  * <h3>Developer Guides</h3>
  *
  * <p>For more information about using Bluetooth, read the <a
  * href="{@docRoot}guide/topics/connectivity/bluetooth.html">Bluetooth</a> developer guide. </div>
  *
  * @see BluetoothSocket
  */
 public final class BluetoothServerSocket implements Closeable {
     private static final String TAG = BluetoothServerSocket.class.getSimpleName();

     @UnsupportedAppUsage(
             publicAlternatives = "Use public {@link BluetoothServerSocket} API instead.")
     /*package*/ final BluetoothSocket mSocket;

     private int mChannel;
     private long mSocketCreationTimeMillis = 0;
     private long mSocketCreationLatencyMillis = 0;

     // BluetoothSocket.getConnectionType() will hide LE.
     // Therefore a new variable need to be maintained here.
     private final int mType;

     /**
      * Construct a socket for incoming connections.
      *
      * @param type type of socket
      * @param auth require the remote device to be authenticated
      * @param encrypt require the connection to be encrypted
      * @param port remote port
      * @throws IOException On error, for example Bluetooth not available, or insufficient privileges
      */
     /*package*/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, int port)
             throws IOException {
         mSocketCreationTimeMillis = System.currentTimeMillis();
         mType = type;
         mChannel = port;
         mSocket = new BluetoothSocket(type, auth, encrypt, port, null);
         if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
             mSocket.setExcludeSdp(true);
         }
         mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
     }

     /**
      * Construct a socket for incoming connections.
      *
      * @param type type of socket
      * @param auth require the remote device to be authenticated
      * @param encrypt require the connection to be encrypted
      * @param port remote port
      * @param pitm enforce person-in-the-middle protection for authentication.
      * @param min16DigitPin enforce a minimum length of 16 digits for a sec mode 2 connection
      * @throws IOException On error, for example Bluetooth not available, or insufficient privileges
      */
     /*package*/ BluetoothServerSocket(
             int type, boolean auth, boolean encrypt, int port, boolean pitm, boolean min16DigitPin)
             throws IOException {
         mSocketCreationTimeMillis = System.currentTimeMillis();
         mType = type;
         mChannel = port;
         mSocket = new BluetoothSocket(type, auth, encrypt, port, null, pitm, min16DigitPin);
         if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
             mSocket.setExcludeSdp(true);
         }
         mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
     }

     /**
      * Construct a socket for incoming connections.
      *
      * @param type type of socket
      * @param auth require the remote device to be authenticated
      * @param encrypt require the connection to be encrypted
      * @param uuid uuid
      * @throws IOException On error, for example Bluetooth not available, or insufficient privileges
      */
     /*package*/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, ParcelUuid uuid)
             throws IOException {
         mSocketCreationTimeMillis = System.currentTimeMillis();
         mType = type;
         mSocket = new BluetoothSocket(type, auth, encrypt, -1, uuid);
         // TODO: This is the same as mChannel = -1 - is this intentional?
         mChannel = mSocket.getPort();
         mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
     }

     /**
      * Construct a socket for incoming connections.
      *
      * @param type type of socket
      * @param auth require the remote device to be authenticated
      * @param encrypt require the connection to be encrypted
      * @param port remote port
      * @param uuid uuid
      * @param pitm enforce person-in-the-middle protection for authentication.
      * @param min16DigitPin enforce a minimum length of 16 digits for a sec mode 2 connection
      * @param dataPath data path used for this socket
      * @param socketName user-friendly name for this socket
      * @param hubId ID of the hub to which the end point belongs
      * @param endpointId ID of the endpoint within the hub that is associated with this socket
      * @param maximumPacketSize The maximum size (in bytes) of a single data packet
      * @throws IOException On error, for example Bluetooth not available, or insufficient privileges
      */
     /*package*/ BluetoothServerSocket(
             int type,
             boolean auth,
             boolean encrypt,
             int port,
             ParcelUuid uuid,
             boolean pitm,
             boolean min16DigitPin,
             int dataPath,
             @NonNull String socketName,
             long hubId,
             long endpointId,
             int maximumPacketSize)
             throws IOException {
         mSocketCreationTimeMillis = System.currentTimeMillis();
         mType = type;
         mChannel = port;
         mSocket =
                 new BluetoothSocket(
                         type,
                         auth,
                         encrypt,
                         port,
                         uuid,
                         pitm,
                         min16DigitPin,
                         dataPath,
                         socketName,
                         hubId,
                         endpointId,
                         maximumPacketSize);
         if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
             mSocket.setExcludeSdp(true);
         }
         mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
     }

     /**
      * Block until a connection is established.
      *
      * <p>Returns a connected {@link BluetoothSocket} on successful connection.
      *
      * <p>Once this call returns, it can be called again to accept subsequent incoming connections.
      *
      * <p>{@link #close} can be used to abort this call from another thread.
      *
      * @return a connected {@link BluetoothSocket}
      * @throws IOException on error, for example this call was aborted, or timeout
      */
     @RequiresNoPermission // Permission is checked when creating the socket
     public BluetoothSocket accept() throws IOException {
         return accept(-1);
     }

     /**
      * Block until a connection is established, with timeout.
      *
      * <p>Returns a connected {@link BluetoothSocket} on successful connection.
      *
      * <p>Once this call returns, it can be called again to accept subsequent incoming connections.
      *
      * <p>{@link #close} can be used to abort this call from another thread.
      *
      * @return a connected {@link BluetoothSocket}
      * @throws IOException on error, for example this call was aborted, or timeout
      */
     @RequiresNoPermission // Permission is checked when creating the socket
     public BluetoothSocket accept(int timeout) throws IOException {
         long socketConnectionTime = System.currentTimeMillis();
         BluetoothSocket acceptedSocket = null;
         try {
             acceptedSocket = mSocket.accept(timeout);
             SocketMetrics.logSocketAccept(
                     acceptedSocket,
                     mSocket,
                     mType,
                     mChannel,
                     timeout,
                     SocketMetrics.RESULT_L2CAP_CONN_SUCCESS,
                     mSocketCreationTimeMillis,
                     mSocketCreationLatencyMillis,
                     socketConnectionTime);
             return acceptedSocket;
         } catch (IOException e) {
             SocketMetrics.logSocketAccept(
                     acceptedSocket,
                     mSocket,
                     mType,
                     mChannel,
                     timeout,
                     SocketMetrics.RESULT_L2CAP_CONN_SERVER_FAILURE,
                     mSocketCreationTimeMillis,
                     mSocketCreationLatencyMillis,
                     socketConnectionTime);
             throw e;
         }
     }

     /**
      * Immediately close this socket, and release all associated resources.
      *
      * <p>Causes blocked calls on this socket in other threads to immediately throw an IOException.
      *
      * <p>Closing the {@link BluetoothServerSocket} will <em>not</em> close any {@link
      * BluetoothSocket} received from {@link #accept()}.
      */
     public void close() throws IOException {
         Log.d(TAG, "BluetoothServerSocket:close() called. mChannel=" + mChannel);
         mSocket.close();
     }

     /*package*/ void setServiceName(String serviceName) {
         mSocket.setServiceName(serviceName);
     }

     /**
      * Returns the channel on which this socket is bound.
      *
      * @hide
      */
     @RequiresNoPermission // Permission is checked when creating the socket
     public int getChannel() {
         return mChannel;
     }

     /**
      * Returns the assigned dynamic protocol/service multiplexer (PSM) value for the listening L2CAP
      * Connection-oriented Channel (CoC) server socket. This server socket must be returned by the
      * {@link BluetoothAdapter#listenUsingL2capChannel()} or {@link
      * BluetoothAdapter#listenUsingInsecureL2capChannel()}. The returned value is undefined if this
      * method is called on non-L2CAP server sockets.
      *
      * @return the assigned PSM or LE_PSM value depending on transport
      */
     @RequiresNoPermission // Permission is checked when creating the socket
     public int getPsm() {
         return mChannel;
     }

     /**
      * Sets the channel on which future sockets are bound. Currently used only when a channel is
      * auto generated.
      */
     /*package*/ void setChannel(int newChannel) {
         /* TODO: From a design/architecture perspective this is wrong.
          *       The bind operation should be conducted through this class
          *       and the resulting port should be kept in mChannel, and
          *       not set from BluetoothAdapter. */
         if (mSocket != null) {
             if (mSocket.getPort() != newChannel) {
                 Log.w(
                         TAG,
                         "The port set is different that the underlying port. mSocket.getPort(): "
                                 + mSocket.getPort()
                                 + " requested newChannel: "
                                 + newChannel);
             }
         }
         mChannel = newChannel;
     }

     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append("ServerSocket: Type: ");
         switch (mSocket.getConnectionType()) {
             case BluetoothSocket.TYPE_RFCOMM -> sb.append("TYPE_RFCOMM");
             case BluetoothSocket.TYPE_L2CAP -> sb.append("TYPE_L2CAP");
             case BluetoothSocket.TYPE_LE -> sb.append("TYPE_LE");
             case BluetoothSocket.TYPE_SCO -> sb.append("TYPE_SCO");
             default -> {} // Nothing to do
         }
         sb.append(" Channel: ").append(mChannel);
         return sb.toString();
     }
 }
	/*
	* Copyright (C) 2009 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.bluetooth;

	import android.annotation.NonNull;
	import android.annotation.RequiresNoPermission;
	import android.compat.annotation.UnsupportedAppUsage;
	import android.os.ParcelUuid;
	import android.util.Log;

	import java.io.Closeable;
	import java.io.IOException;

	/**
	* A listening Bluetooth socket.
	*
	* <p>The interface for Bluetooth Sockets is similar to that of TCP sockets: {@link java.net.Socket}
	* and {@link java.net.ServerSocket}. On the server side, use a {@link BluetoothServerSocket} to
	* create a listening server socket. When a connection is accepted by the {@link
	* BluetoothServerSocket}, it will return a new {@link BluetoothSocket} to manage the connection. On
	* the client side, use a single {@link BluetoothSocket} to both initiate an outgoing connection and
	* to manage the connection.
	*
	* <p>For Bluetooth BR/EDR, the most common type of socket is RFCOMM, which is the type supported by
	* the Android APIs. RFCOMM is a connection-oriented, streaming transport over Bluetooth BR/EDR. It
	* is also known as the Serial Port Profile (SPP). To create a listening {@link
	* BluetoothServerSocket} that's ready for incoming Bluetooth BR/EDR connections, use {@link
	* BluetoothAdapter#listenUsingRfcommWithServiceRecord
	* BluetoothAdapter.listenUsingRfcommWithServiceRecord()}.
	*
	* <p>For Bluetooth LE, the socket uses LE Connection-oriented Channel (CoC). LE CoC is a
	* connection-oriented, streaming transport over Bluetooth LE and has a credit-based flow control.
	* Correspondingly, use {@link BluetoothAdapter#listenUsingL2capChannel
	* BluetoothAdapter.listenUsingL2capChannel()} to create a listening {@link BluetoothServerSocket}
	* that's ready for incoming Bluetooth LE CoC connections. For LE CoC, you can use {@link #getPsm()}
	* to get the protocol/service multiplexer (PSM) value that the peer needs to use to connect to your
	* socket.
	*
	* <p>After the listening {@link BluetoothServerSocket} is created, call {@link #accept()} to listen
	* for incoming connection requests. This call will block until a connection is established, at
	* which point, it will return a {@link BluetoothSocket} to manage the connection. Once the {@link
	* BluetoothSocket} is acquired, it's a good idea to call {@link #close()} on the {@link
	* BluetoothServerSocket} when it's no longer needed for accepting connections. Closing the {@link
	* BluetoothServerSocket} will <em>not</em> close the returned {@link BluetoothSocket}.
	*
	* <p>{@link BluetoothServerSocket} is thread safe. In particular, {@link #close} will always
	* immediately abort ongoing operations and close the server socket.
	*
	* <p><div class="special reference">
	*
	* <h3>Developer Guides</h3>
	*
	* <p>For more information about using Bluetooth, read the <a
	* href="{@docRoot}guide/topics/connectivity/bluetooth.html">Bluetooth</a> developer guide. </div>
	*
	* @see BluetoothSocket
	*/
	public final class BluetoothServerSocket implements Closeable {
	private static final String TAG = BluetoothServerSocket.class.getSimpleName();

	@UnsupportedAppUsage(
	publicAlternatives = "Use public {@link BluetoothServerSocket} API instead.")
	/package/ final BluetoothSocket mSocket;

	private int mChannel;
	private long mSocketCreationTimeMillis = 0;
	private long mSocketCreationLatencyMillis = 0;

	// BluetoothSocket.getConnectionType() will hide LE.
	// Therefore a new variable need to be maintained here.
	private final int mType;

	/**
	* Construct a socket for incoming connections.
	*
	* @param type type of socket
	* @param auth require the remote device to be authenticated
	* @param encrypt require the connection to be encrypted
	* @param port remote port
	* @throws IOException On error, for example Bluetooth not available, or insufficient privileges
	*/
	/package/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, int port)
	throws IOException {
	mSocketCreationTimeMillis = System.currentTimeMillis();
	mType = type;
	mChannel = port;
	mSocket = new BluetoothSocket(type, auth, encrypt, port, null);
	if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
	mSocket.setExcludeSdp(true);
	}
	mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
	}

	/**
	* Construct a socket for incoming connections.
	*
	* @param type type of socket
	* @param auth require the remote device to be authenticated
	* @param encrypt require the connection to be encrypted
	* @param port remote port
	* @param pitm enforce person-in-the-middle protection for authentication.
	* @param min16DigitPin enforce a minimum length of 16 digits for a sec mode 2 connection
	* @throws IOException On error, for example Bluetooth not available, or insufficient privileges
	*/
	/package/ BluetoothServerSocket(
	int type, boolean auth, boolean encrypt, int port, boolean pitm, boolean min16DigitPin)
	throws IOException {
	mSocketCreationTimeMillis = System.currentTimeMillis();
	mType = type;
	mChannel = port;
	mSocket = new BluetoothSocket(type, auth, encrypt, port, null, pitm, min16DigitPin);
	if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
	mSocket.setExcludeSdp(true);
	}
	mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
	}

	/**
	* Construct a socket for incoming connections.
	*
	* @param type type of socket
	* @param auth require the remote device to be authenticated
	* @param encrypt require the connection to be encrypted
	* @param uuid uuid
	* @throws IOException On error, for example Bluetooth not available, or insufficient privileges
	*/
	/package/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, ParcelUuid uuid)
	throws IOException {
	mSocketCreationTimeMillis = System.currentTimeMillis();
	mType = type;
	mSocket = new BluetoothSocket(type, auth, encrypt, -1, uuid);
	// TODO: This is the same as mChannel = -1 - is this intentional?
	mChannel = mSocket.getPort();
	mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
	}

	/**
	* Construct a socket for incoming connections.
	*
	* @param type type of socket
	* @param auth require the remote device to be authenticated
	* @param encrypt require the connection to be encrypted
	* @param port remote port
	* @param uuid uuid
	* @param pitm enforce person-in-the-middle protection for authentication.
	* @param min16DigitPin enforce a minimum length of 16 digits for a sec mode 2 connection
	* @param dataPath data path used for this socket
	* @param socketName user-friendly name for this socket
	* @param hubId ID of the hub to which the end point belongs
	* @param endpointId ID of the endpoint within the hub that is associated with this socket
	* @param maximumPacketSize The maximum size (in bytes) of a single data packet
	* @throws IOException On error, for example Bluetooth not available, or insufficient privileges
	*/
	/package/ BluetoothServerSocket(
	int type,
	boolean auth,
	boolean encrypt,
	int port,
	ParcelUuid uuid,
	boolean pitm,
	boolean min16DigitPin,
	int dataPath,
	@NonNull String socketName,
	long hubId,
	long endpointId,
	int maximumPacketSize)
	throws IOException {
	mSocketCreationTimeMillis = System.currentTimeMillis();
	mType = type;
	mChannel = port;
	mSocket =
	new BluetoothSocket(
	type,
	auth,
	encrypt,
	port,
	uuid,
	pitm,
	min16DigitPin,
	dataPath,
	socketName,
	hubId,
	endpointId,
	maximumPacketSize);
	if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
	mSocket.setExcludeSdp(true);
	}
	mSocketCreationLatencyMillis = System.currentTimeMillis() - mSocketCreationTimeMillis;
	}

	/**
	* Block until a connection is established.
	*
	* <p>Returns a connected {@link BluetoothSocket} on successful connection.
	*
	* <p>Once this call returns, it can be called again to accept subsequent incoming connections.
	*
	* <p>{@link #close} can be used to abort this call from another thread.
	*
	* @return a connected {@link BluetoothSocket}
	* @throws IOException on error, for example this call was aborted, or timeout
	*/
	@RequiresNoPermission // Permission is checked when creating the socket
	public BluetoothSocket accept() throws IOException {
	return accept(-1);
	}

	/**
	* Block until a connection is established, with timeout.
	*
	* <p>Returns a connected {@link BluetoothSocket} on successful connection.
	*
	* <p>Once this call returns, it can be called again to accept subsequent incoming connections.
	*
	* <p>{@link #close} can be used to abort this call from another thread.
	*
	* @return a connected {@link BluetoothSocket}
	* @throws IOException on error, for example this call was aborted, or timeout
	*/
	@RequiresNoPermission // Permission is checked when creating the socket
	public BluetoothSocket accept(int timeout) throws IOException {
	long socketConnectionTime = System.currentTimeMillis();
	BluetoothSocket acceptedSocket = null;
	try {
	acceptedSocket = mSocket.accept(timeout);
	SocketMetrics.logSocketAccept(
	acceptedSocket,
	mSocket,
	mType,
	mChannel,
	timeout,
	SocketMetrics.RESULT_L2CAP_CONN_SUCCESS,
	mSocketCreationTimeMillis,
	mSocketCreationLatencyMillis,
	socketConnectionTime);
	return acceptedSocket;
	} catch (IOException e) {
	SocketMetrics.logSocketAccept(
	acceptedSocket,
	mSocket,
	mType,
	mChannel,
	timeout,
	SocketMetrics.RESULT_L2CAP_CONN_SERVER_FAILURE,
	mSocketCreationTimeMillis,
	mSocketCreationLatencyMillis,
	socketConnectionTime);
	throw e;
	}
	}

	/**
	* Immediately close this socket, and release all associated resources.
	*
	* <p>Causes blocked calls on this socket in other threads to immediately throw an IOException.
	*
	* <p>Closing the {@link BluetoothServerSocket} will <em>not</em> close any {@link
	* BluetoothSocket} received from {@link #accept()}.
	*/
	public void close() throws IOException {
	Log.d(TAG, "BluetoothServerSocket:close() called. mChannel=" + mChannel);
	mSocket.close();
	}

	/package/ void setServiceName(String serviceName) {
	mSocket.setServiceName(serviceName);
	}

	/**
	* Returns the channel on which this socket is bound.
	*
	* @hide
	*/
	@RequiresNoPermission // Permission is checked when creating the socket
	public int getChannel() {
	return mChannel;
	}

	/**
	* Returns the assigned dynamic protocol/service multiplexer (PSM) value for the listening L2CAP
	* Connection-oriented Channel (CoC) server socket. This server socket must be returned by the
	* {@link BluetoothAdapter#listenUsingL2capChannel()} or {@link
	* BluetoothAdapter#listenUsingInsecureL2capChannel()}. The returned value is undefined if this
	* method is called on non-L2CAP server sockets.
	*
	* @return the assigned PSM or LE_PSM value depending on transport
	*/
	@RequiresNoPermission // Permission is checked when creating the socket
	public int getPsm() {
	return mChannel;
	}

	/**
	* Sets the channel on which future sockets are bound. Currently used only when a channel is
	* auto generated.
	*/
	/package/ void setChannel(int newChannel) {
	/* TODO: From a design/architecture perspective this is wrong.
	* The bind operation should be conducted through this class
	* and the resulting port should be kept in mChannel, and
	* not set from BluetoothAdapter. */
	if (mSocket != null) {
	if (mSocket.getPort() != newChannel) {
	Log.w(
	TAG,
	"The port set is different that the underlying port. mSocket.getPort(): "
	+ mSocket.getPort()
	+ " requested newChannel: "
	+ newChannel);
	}
	}
	mChannel = newChannel;
	}

	@Override
	public String toString() {
	StringBuilder sb = new StringBuilder();
	sb.append("ServerSocket: Type: ");
	switch (mSocket.getConnectionType()) {
	case BluetoothSocket.TYPE_RFCOMM -> sb.append("TYPE_RFCOMM");
	case BluetoothSocket.TYPE_L2CAP -> sb.append("TYPE_L2CAP");
	case BluetoothSocket.TYPE_LE -> sb.append("TYPE_LE");
	case BluetoothSocket.TYPE_SCO -> sb.append("TYPE_SCO");
	default -> {} // Nothing to do
	}
	sb.append(" Channel: ").append(mChannel);
	return sb.toString();
	}
	}