1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.bluetooth;
18
19import android.os.Handler;
20import android.os.ParcelUuid;
21import android.util.Log;
22
23import java.io.Closeable;
24import java.io.IOException;
25
26/**
27 * A listening Bluetooth socket.
28 *
29 * <p>The interface for Bluetooth Sockets is similar to that of TCP sockets:
30 * {@link java.net.Socket} and {@link java.net.ServerSocket}. On the server
31 * side, use a {@link BluetoothServerSocket} to create a listening server
32 * socket. When a connection is accepted by the {@link BluetoothServerSocket},
33 * it will return a new {@link BluetoothSocket} to manage the connection.
34 * On the client side, use a single {@link BluetoothSocket} to both initiate
35 * an outgoing connection and to manage the connection.
36 *
37 * <p>The most common type of Bluetooth socket is RFCOMM, which is the type
38 * supported by the Android APIs. RFCOMM is a connection-oriented, streaming
39 * transport over Bluetooth. It is also known as the Serial Port Profile (SPP).
40 *
41 * <p>To create a listening {@link BluetoothServerSocket} that's ready for
42 * incoming connections, use
43 * {@link BluetoothAdapter#listenUsingRfcommWithServiceRecord
44 * BluetoothAdapter.listenUsingRfcommWithServiceRecord()}. Then call
45 * {@link #accept()} to listen for incoming connection requests. This call
46 * will block until a connection is established, at which point, it will return
47 * a {@link BluetoothSocket} to manage the connection. Once the {@link
48 * BluetoothSocket} is acquired, it's a good idea to call {@link #close()} on
49 * the {@link BluetoothServerSocket} when it's no longer needed for accepting
50 * connections. Closing the {@link BluetoothServerSocket} will <em>not</em>
51 * close the returned {@link BluetoothSocket}.
52 *
53 * <p>{@link BluetoothServerSocket} is thread
54 * safe. In particular, {@link #close} will always immediately abort ongoing
55 * operations and close the server socket.
56 *
57 * <p class="note"><strong>Note:</strong>
58 * Requires the {@link android.Manifest.permission#BLUETOOTH} permission.
59 *
60 * <div class="special reference">
61 * <h3>Developer Guides</h3>
62 * <p>For more information about using Bluetooth, read the
63 * <a href="{@docRoot}guide/topics/connectivity/bluetooth.html">Bluetooth</a> developer guide.</p>
64 * </div>
65 *
66 * {@see BluetoothSocket}
67 */
68public final class BluetoothServerSocket implements Closeable {
69
70    private static final String TAG = "BluetoothServerSocket";
71    private static final boolean DBG = false;
72    /*package*/ final BluetoothSocket mSocket;
73    private Handler mHandler;
74    private int mMessage;
75    private int mChannel;
76
77    /**
78     * Construct a socket for incoming connections.
79     *
80     * @param type type of socket
81     * @param auth require the remote device to be authenticated
82     * @param encrypt require the connection to be encrypted
83     * @param port remote port
84     * @throws IOException On error, for example Bluetooth not available, or insufficient
85     * privileges
86     */
87    /*package*/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, int port)
88            throws IOException {
89        mChannel = port;
90        mSocket = new BluetoothSocket(type, -1, auth, encrypt, null, port, null);
91        if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
92            mSocket.setExcludeSdp(true);
93        }
94    }
95
96    /**
97     * Construct a socket for incoming connections.
98     *
99     * @param type type of socket
100     * @param auth require the remote device to be authenticated
101     * @param encrypt require the connection to be encrypted
102     * @param port remote port
103     * @param mitm enforce man-in-the-middle protection for authentication.
104     * @param min16DigitPin enforce a minimum length of 16 digits for a sec mode 2 connection
105     * @throws IOException On error, for example Bluetooth not available, or insufficient
106     * privileges
107     */
108    /*package*/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, int port,
109            boolean mitm, boolean min16DigitPin)
110            throws IOException {
111        mChannel = port;
112        mSocket = new BluetoothSocket(type, -1, auth, encrypt, null, port, null, mitm,
113                min16DigitPin);
114        if (port == BluetoothAdapter.SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
115            mSocket.setExcludeSdp(true);
116        }
117    }
118
119    /**
120     * Construct a socket for incoming connections.
121     *
122     * @param type type of socket
123     * @param auth require the remote device to be authenticated
124     * @param encrypt require the connection to be encrypted
125     * @param uuid uuid
126     * @throws IOException On error, for example Bluetooth not available, or insufficient
127     * privileges
128     */
129    /*package*/ BluetoothServerSocket(int type, boolean auth, boolean encrypt, ParcelUuid uuid)
130            throws IOException {
131        mSocket = new BluetoothSocket(type, -1, auth, encrypt, null, -1, uuid);
132        // TODO: This is the same as mChannel = -1 - is this intentional?
133        mChannel = mSocket.getPort();
134    }
135
136
137    /**
138     * Block until a connection is established.
139     * <p>Returns a connected {@link BluetoothSocket} on successful connection.
140     * <p>Once this call returns, it can be called again to accept subsequent
141     * incoming connections.
142     * <p>{@link #close} can be used to abort this call from another thread.
143     *
144     * @return a connected {@link BluetoothSocket}
145     * @throws IOException on error, for example this call was aborted, or timeout
146     */
147    public BluetoothSocket accept() throws IOException {
148        return accept(-1);
149    }
150
151    /**
152     * Block until a connection is established, with timeout.
153     * <p>Returns a connected {@link BluetoothSocket} on successful connection.
154     * <p>Once this call returns, it can be called again to accept subsequent
155     * incoming connections.
156     * <p>{@link #close} can be used to abort this call from another thread.
157     *
158     * @return a connected {@link BluetoothSocket}
159     * @throws IOException on error, for example this call was aborted, or timeout
160     */
161    public BluetoothSocket accept(int timeout) throws IOException {
162        return mSocket.accept(timeout);
163    }
164
165    /**
166     * Immediately close this socket, and release all associated resources.
167     * <p>Causes blocked calls on this socket in other threads to immediately
168     * throw an IOException.
169     * <p>Closing the {@link BluetoothServerSocket} will <em>not</em>
170     * close any {@link BluetoothSocket} received from {@link #accept()}.
171     */
172    public void close() throws IOException {
173        if (DBG) Log.d(TAG, "BluetoothServerSocket:close() called. mChannel=" + mChannel);
174        synchronized (this) {
175            if (mHandler != null) {
176                mHandler.obtainMessage(mMessage).sendToTarget();
177            }
178        }
179        mSocket.close();
180    }
181
182    /*package*/
183    synchronized void setCloseHandler(Handler handler, int message) {
184        mHandler = handler;
185        mMessage = message;
186    }
187
188    /*package*/ void setServiceName(String serviceName) {
189        mSocket.setServiceName(serviceName);
190    }
191
192    /**
193     * Returns the channel on which this socket is bound.
194     *
195     * @hide
196     */
197    public int getChannel() {
198        return mChannel;
199    }
200
201    /**
202     * Returns the assigned dynamic protocol/service multiplexer (PSM) value for the listening L2CAP
203     * Connection-oriented Channel (CoC) server socket. This server socket must be returned by the
204     * {#link BluetoothAdapter.listenUsingL2capCoc(int)} or {#link
205     * BluetoothAdapter.listenUsingInsecureL2capCoc(int)}. The returned value is undefined if this
206     * method is called on non-L2CAP server sockets.
207     *
208     * @return the assigned PSM or LE_PSM value depending on transport
209     * @hide
210     */
211    public int getPsm() {
212        return mChannel;
213    }
214
215    /**
216     * Sets the channel on which future sockets are bound.
217     * Currently used only when a channel is auto generated.
218     */
219    /*package*/ void setChannel(int newChannel) {
220        /* TODO: From a design/architecture perspective this is wrong.
221         *       The bind operation should be conducted through this class
222         *       and the resulting port should be kept in mChannel, and
223         *       not set from BluetoothAdapter. */
224        if (mSocket != null) {
225            if (mSocket.getPort() != newChannel) {
226                Log.w(TAG, "The port set is different that the underlying port. mSocket.getPort(): "
227                        + mSocket.getPort() + " requested newChannel: " + newChannel);
228            }
229        }
230        mChannel = newChannel;
231    }
232
233    @Override
234    public String toString() {
235        StringBuilder sb = new StringBuilder();
236        sb.append("ServerSocket: Type: ");
237        switch (mSocket.getConnectionType()) {
238            case BluetoothSocket.TYPE_RFCOMM: {
239                sb.append("TYPE_RFCOMM");
240                break;
241            }
242            case BluetoothSocket.TYPE_L2CAP: {
243                sb.append("TYPE_L2CAP");
244                break;
245            }
246            case BluetoothSocket.TYPE_L2CAP_LE: {
247                sb.append("TYPE_L2CAP_LE");
248                break;
249            }
250            case BluetoothSocket.TYPE_SCO: {
251                sb.append("TYPE_SCO");
252                break;
253            }
254        }
255        sb.append(" Channel: ").append(mChannel);
256        return sb.toString();
257    }
258}
259