/* * 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.bluetooth.IBluetoothCallback; import android.os.ParcelUuid; import android.os.RemoteException; import android.util.Log; import java.io.Closeable; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.concurrent.locks.ReentrantReadWriteLock; /** * A connected or connecting Bluetooth socket. * *

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. * *

The most common type of Bluetooth socket is RFCOMM, which is the type * supported by the Android APIs. RFCOMM is a connection-oriented, streaming * transport over Bluetooth. It is also known as the Serial Port Profile (SPP). * *

To create a {@link BluetoothSocket} for connecting to a known device, use * {@link BluetoothDevice#createRfcommSocketToServiceRecord * BluetoothDevice.createRfcommSocketToServiceRecord()}. * Then call {@link #connect()} to attempt a connection to the remote device. * This call will block until a connection is established or the connection * fails. * *

To create a {@link BluetoothSocket} as a server (or "host"), see the * {@link BluetoothServerSocket} documentation. * *

Once the socket is connected, whether initiated as a client or accepted * as a server, open the IO streams by calling {@link #getInputStream} and * {@link #getOutputStream} in order to retrieve {@link java.io.InputStream} * and {@link java.io.OutputStream} objects, respectively, which are * automatically connected to the socket. * *

{@link BluetoothSocket} is thread * safe. In particular, {@link #close} will always immediately abort ongoing * operations and close the socket. * *

Note: * Requires the {@link android.Manifest.permission#BLUETOOTH} permission. * *

*

Developer Guides

*

For more information about using Bluetooth, read the * Bluetooth developer guide.

*
* * {@see BluetoothServerSocket} * {@see java.io.InputStream} * {@see java.io.OutputStream} */ public final class BluetoothSocket implements Closeable { private static final String TAG = "BluetoothSocket"; /** @hide */ public static final int MAX_RFCOMM_CHANNEL = 30; /** Keep TYPE_ fields in sync with BluetoothSocket.cpp */ /*package*/ static final int TYPE_RFCOMM = 1; /*package*/ static final int TYPE_SCO = 2; /*package*/ static final int TYPE_L2CAP = 3; /*package*/ static final int EBADFD = 77; /*package*/ static final int EADDRINUSE = 98; private final int mType; /* one of TYPE_RFCOMM etc */ private final BluetoothDevice mDevice; /* remote device */ private final String mAddress; /* remote address */ private final boolean mAuth; private final boolean mEncrypt; private final BluetoothInputStream mInputStream; private final BluetoothOutputStream mOutputStream; private final SdpHelper mSdp; private int mPort; /* RFCOMM channel or L2CAP psm */ private enum SocketState { INIT, CONNECTED, CLOSED } /** prevents all native calls after destroyNative() */ private SocketState mSocketState; /** protects mSocketState */ private final ReentrantReadWriteLock mLock; /** used by native code only */ private int mSocketData; /** * Construct a BluetoothSocket. * @param type type of socket * @param fd fd to use for connected socket, or -1 for a new socket * @param auth require the remote device to be authenticated * @param encrypt require the connection to be encrypted * @param device remote device that this socket can connect to * @param port remote port * @param uuid SDP uuid * @throws IOException On error, for example Bluetooth not available, or * insufficient privileges */ /*package*/ BluetoothSocket(int type, int fd, boolean auth, boolean encrypt, BluetoothDevice device, int port, ParcelUuid uuid) throws IOException { if (type == BluetoothSocket.TYPE_RFCOMM && uuid == null && fd == -1) { if (port < 1 || port > MAX_RFCOMM_CHANNEL) { throw new IOException("Invalid RFCOMM channel: " + port); } } if (uuid == null) { mPort = port; mSdp = null; } else { mSdp = new SdpHelper(device, uuid); mPort = -1; } mType = type; mAuth = auth; mEncrypt = encrypt; mDevice = device; if (device == null) { mAddress = null; } else { mAddress = device.getAddress(); } if (fd == -1) { initSocketNative(); } else { initSocketFromFdNative(fd); } mInputStream = new BluetoothInputStream(this); mOutputStream = new BluetoothOutputStream(this); mSocketState = SocketState.INIT; mLock = new ReentrantReadWriteLock(); } /** * Construct a BluetoothSocket from address. Used by native code. * @param type type of socket * @param fd fd to use for connected socket, or -1 for a new socket * @param auth require the remote device to be authenticated * @param encrypt require the connection to be encrypted * @param address remote device that this socket can connect to * @param port remote port * @throws IOException On error, for example Bluetooth not available, or * insufficient privileges */ private BluetoothSocket(int type, int fd, boolean auth, boolean encrypt, String address, int port) throws IOException { this(type, fd, auth, encrypt, new BluetoothDevice(address), port, null); } /** @hide */ @Override protected void finalize() throws Throwable { try { close(); } finally { super.finalize(); } } /** * Attempt to connect to a remote device. *

This method will block until a connection is made or the connection * fails. If this method returns without an exception then this socket * is now connected. *

Creating new connections to * remote Bluetooth devices should not be attempted while device discovery * is in progress. Device discovery is a heavyweight procedure on the * Bluetooth adapter and will significantly slow a device connection. * Use {@link BluetoothAdapter#cancelDiscovery()} to cancel an ongoing * discovery. Discovery is not managed by the Activity, * but is run as a system service, so an application should always call * {@link BluetoothAdapter#cancelDiscovery()} even if it * did not directly request a discovery, just to be sure. *

{@link #close} can be used to abort this call from another thread. * @throws IOException on error, for example connection failure */ public void connect() throws IOException { mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) throw new IOException("socket closed"); if (mSdp != null) { mPort = mSdp.doSdp(); // blocks } connectNative(); // blocks mSocketState = SocketState.CONNECTED; } finally { mLock.readLock().unlock(); } } /** * Immediately close this socket, and release all associated resources. *

Causes blocked calls on this socket in other threads to immediately * throw an IOException. */ public void close() throws IOException { // abort blocking operations on the socket mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) return; if (mSdp != null) { mSdp.cancel(); } abortNative(); } finally { mLock.readLock().unlock(); } // all native calls are guaranteed to immediately return after // abortNative(), so this lock should immediately acquire mLock.writeLock().lock(); try { mSocketState = SocketState.CLOSED; destroyNative(); } finally { mLock.writeLock().unlock(); } } /** * Get the remote device this socket is connecting, or connected, to. * @return remote device */ public BluetoothDevice getRemoteDevice() { return mDevice; } /** * Get the input stream associated with this socket. *

The input stream will be returned even if the socket is not yet * connected, but operations on that stream will throw IOException until * the associated socket is connected. * @return InputStream */ public InputStream getInputStream() throws IOException { return mInputStream; } /** * Get the output stream associated with this socket. *

The output stream will be returned even if the socket is not yet * connected, but operations on that stream will throw IOException until * the associated socket is connected. * @return OutputStream */ public OutputStream getOutputStream() throws IOException { return mOutputStream; } /** * Get the connection status of this socket, ie, whether there is an active connection with * remote device. * @return true if connected * false if not connected */ public boolean isConnected() { return (mSocketState == SocketState.CONNECTED); } /** * Currently returns unix errno instead of throwing IOException, * so that BluetoothAdapter can check the error code for EADDRINUSE */ /*package*/ int bindListen() { mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) return EBADFD; return bindListenNative(); } finally { mLock.readLock().unlock(); } } /*package*/ BluetoothSocket accept(int timeout) throws IOException { mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) throw new IOException("socket closed"); BluetoothSocket acceptedSocket = acceptNative(timeout); mSocketState = SocketState.CONNECTED; return acceptedSocket; } finally { mLock.readLock().unlock(); } } /*package*/ int available() throws IOException { mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) throw new IOException("socket closed"); return availableNative(); } finally { mLock.readLock().unlock(); } } /*package*/ int read(byte[] b, int offset, int length) throws IOException { mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) throw new IOException("socket closed"); return readNative(b, offset, length); } finally { mLock.readLock().unlock(); } } /*package*/ int write(byte[] b, int offset, int length) throws IOException { mLock.readLock().lock(); try { if (mSocketState == SocketState.CLOSED) throw new IOException("socket closed"); return writeNative(b, offset, length); } finally { mLock.readLock().unlock(); } } private native void initSocketNative() throws IOException; private native void initSocketFromFdNative(int fd) throws IOException; private native void connectNative() throws IOException; private native int bindListenNative(); private native BluetoothSocket acceptNative(int timeout) throws IOException; private native int availableNative() throws IOException; private native int readNative(byte[] b, int offset, int length) throws IOException; private native int writeNative(byte[] b, int offset, int length) throws IOException; private native void abortNative() throws IOException; private native void destroyNative() throws IOException; /** * Throws an IOException for given posix errno. Done natively so we can * use strerr to convert to string error. */ /*package*/ native void throwErrnoNative(int errno) throws IOException; /** * Helper to perform blocking SDP lookup. */ private static class SdpHelper extends IBluetoothCallback.Stub { private final IBluetooth service; private final ParcelUuid uuid; private final BluetoothDevice device; private int channel; private boolean canceled; public SdpHelper(BluetoothDevice device, ParcelUuid uuid) { service = BluetoothDevice.getService(); this.device = device; this.uuid = uuid; canceled = false; } /** * Returns the RFCOMM channel for the UUID, or throws IOException * on failure. */ public synchronized int doSdp() throws IOException { if (canceled) throw new IOException("Service discovery canceled"); channel = -1; boolean inProgress = false; try { inProgress = service.fetchRemoteUuids(device.getAddress(), uuid, this); } catch (RemoteException e) {Log.e(TAG, "", e);} if (!inProgress) throw new IOException("Unable to start Service Discovery"); try { /* 12 second timeout as a precaution - onRfcommChannelFound * should always occur before the timeout */ wait(12000); // block } catch (InterruptedException e) {} if (canceled) throw new IOException("Service discovery canceled"); if (channel < 1) throw new IOException("Service discovery failed"); return channel; } /** Object cannot be re-used after calling cancel() */ public synchronized void cancel() { if (!canceled) { canceled = true; channel = -1; notifyAll(); // unblock } } public synchronized void onRfcommChannelFound(int channel) { if (!canceled) { this.channel = channel; notifyAll(); // unblock } } } }