java.net.DatagramSocket Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.net;
import java.io.Closeable;
import java.io.FileDescriptor;
import java.io.IOException;
import java.nio.channels.DatagramChannel;
import libcore.io.ErrnoException;
import libcore.io.IoBridge;
import libcore.io.Libcore;
import static libcore.io.OsConstants.*;
/**
* This class implements a UDP socket for sending and receiving {@code
* DatagramPacket}. A {@code DatagramSocket} object can be used for both
* endpoints of a connection for a packet delivery service.
*
* @see DatagramPacket
* @see DatagramSocketImplFactory
*/
public class DatagramSocket implements Closeable {
DatagramSocketImpl impl;
InetAddress address;
int port = -1;
static DatagramSocketImplFactory factory;
boolean isBound = false;
private boolean isConnected = false;
private SocketException pendingConnectException;
private boolean isClosed = false;
private Object lock = new Object();
/**
* Constructs a UDP datagram socket which is bound to any available port on
* the localhost.
*
* @throws SocketException
* if an error occurs while creating or binding the socket.
*/
public DatagramSocket() throws SocketException {
this(0);
}
/**
* Constructs a UDP datagram socket which is bound to the specific port
* {@code aPort} on the localhost. Valid values for {@code aPort} are
* between 0 and 65535 inclusive.
*
* @param aPort
* the port to bind on the localhost.
* @throws SocketException
* if an error occurs while creating or binding the socket.
*/
public DatagramSocket(int aPort) throws SocketException {
checkPort(aPort);
createSocket(aPort, Inet4Address.ANY);
}
/**
* Constructs a UDP datagram socket which is bound to the specific local
* address {@code addr} on port {@code aPort}. Valid values for {@code
* aPort} are between 0 and 65535 inclusive.
*
* @param aPort
* the port to bind on the localhost.
* @param addr
* the address to bind on the localhost.
* @throws SocketException
* if an error occurs while creating or binding the socket.
*/
public DatagramSocket(int aPort, InetAddress addr) throws SocketException {
checkPort(aPort);
createSocket(aPort, (addr == null) ? Inet4Address.ANY : addr);
}
private void checkPort(int aPort) {
if (aPort < 0 || aPort > 65535) {
throw new IllegalArgumentException("Port out of range: " + aPort);
}
}
/**
* Closes this UDP datagram socket and all possibly associated channels.
*/
// In the documentation jdk1.1.7a/guide/net/miscNet.html, this method is
// noted as not being synchronized.
public void close() {
isClosed = true;
impl.close();
}
/**
* Disconnects this UDP datagram socket from the remote host. This method
* called on an unconnected socket does nothing.
*/
public void disconnect() {
if (isClosed() || !isConnected()) {
return;
}
impl.disconnect();
address = null;
port = -1;
isConnected = false;
}
synchronized void createSocket(int aPort, InetAddress addr) throws SocketException {
impl = factory != null ? factory.createDatagramSocketImpl()
: new PlainDatagramSocketImpl();
impl.create();
try {
impl.bind(aPort, addr);
isBound = true;
} catch (SocketException e) {
close();
throw e;
}
}
/**
* Gets the {@code InetAddress} instance representing the remote address to
* which this UDP datagram socket is connected.
*
* @return the remote address this socket is connected to or {@code null} if
* this socket is not connected.
*/
public InetAddress getInetAddress() {
return address;
}
/**
* Returns the local address to which this socket is bound,
* or {@code null} if this socket is closed.
*/
public InetAddress getLocalAddress() {
try {
return IoBridge.getSocketLocalAddress(impl.fd);
} catch (SocketException ex) {
return null;
}
}
/**
* Gets the local port which this socket is bound to.
*
* @return the local port of this socket or {@code -1} if this socket is
* closed and {@code 0} if it is unbound.
*/
public int getLocalPort() {
if (isClosed()) {
return -1;
}
if (!isBound()) {
return 0;
}
return impl.getLocalPort();
}
/**
* Gets the remote port which this socket is connected to.
*
* @return the remote port of this socket. The return value {@code -1}
* indicates that this socket is not connected.
*/
public int getPort() {
return port;
}
/**
* Indicates whether this socket is multicast or not.
*
* @return the return value is always {@code false}.
*/
boolean isMulticastSocket() {
return false;
}
/**
* Returns this socket's {@link SocketOptions#SO_RCVBUF receive buffer size}.
*/
public synchronized int getReceiveBufferSize() throws SocketException {
checkOpen();
return ((Integer) impl.getOption(SocketOptions.SO_RCVBUF)).intValue();
}
/**
* Returns this socket's {@link SocketOptions#SO_SNDBUF send buffer size}.
*/
public synchronized int getSendBufferSize() throws SocketException {
checkOpen();
return ((Integer) impl.getOption(SocketOptions.SO_SNDBUF)).intValue();
}
/**
* Gets the socket {@link SocketOptions#SO_TIMEOUT receive timeout}.
*
* @throws SocketException
* if an error occurs while getting the option value.
*/
public synchronized int getSoTimeout() throws SocketException {
checkOpen();
return ((Integer) impl.getOption(SocketOptions.SO_TIMEOUT)).intValue();
}
/**
* Receives a packet from this socket and stores it in the argument {@code
* pack}. All fields of {@code pack} must be set according to the data
* received. If the received data is longer than the packet buffer size it
* is truncated. This method blocks until a packet is received or a timeout
* has expired.
*
* @param pack
* the {@code DatagramPacket} to store the received data.
* @throws IOException
* if an error occurs while receiving the packet.
*/
public synchronized void receive(DatagramPacket pack) throws IOException {
checkOpen();
ensureBound();
if (pack == null) {
throw new NullPointerException("pack == null");
}
if (pendingConnectException != null) {
throw new SocketException("Pending connect failure", pendingConnectException);
}
pack.resetLengthForReceive();
impl.receive(pack);
}
/**
* Sends a packet over this socket.
*
* @param pack
* the {@code DatagramPacket} which has to be sent.
* @throws IOException
* if an error occurs while sending the packet.
*/
public void send(DatagramPacket pack) throws IOException {
checkOpen();
ensureBound();
InetAddress packAddr = pack.getAddress();
if (address != null) { // The socket is connected
if (packAddr != null) {
if (!address.equals(packAddr) || port != pack.getPort()) {
throw new IllegalArgumentException("Packet address mismatch with connected address");
}
} else {
pack.setAddress(address);
pack.setPort(port);
}
} else {
// not connected so the target address is not allowed to be null
if (packAddr == null) {
throw new NullPointerException("Destination address is null");
}
}
impl.send(pack);
}
/**
* Sets the network interface used by this socket. Any packets sent
* via this socket are transmitted via the specified interface. Any
* packets received by this socket will come from the specified
* interface. Broadcast datagrams received on this interface will
* be processed by this socket. This corresponds to Linux's SO_BINDTODEVICE.
*
* @hide used by GoogleTV for DHCP
*/
public void setNetworkInterface(NetworkInterface netInterface) throws SocketException {
if (netInterface == null) {
throw new NullPointerException("netInterface == null");
}
try {
Libcore.os.setsockoptIfreq(impl.fd, SOL_SOCKET, SO_BINDTODEVICE, netInterface.getName());
} catch (ErrnoException errnoException) {
throw errnoException.rethrowAsSocketException();
}
}
/**
* Sets this socket's {@link SocketOptions#SO_SNDBUF send buffer size}.
*/
public synchronized void setSendBufferSize(int size) throws SocketException {
if (size < 1) {
throw new IllegalArgumentException("size < 1");
}
checkOpen();
impl.setOption(SocketOptions.SO_SNDBUF, Integer.valueOf(size));
}
/**
* Sets this socket's {@link SocketOptions#SO_SNDBUF receive buffer size}.
*/
public synchronized void setReceiveBufferSize(int size) throws SocketException {
if (size < 1) {
throw new IllegalArgumentException("size < 1");
}
checkOpen();
impl.setOption(SocketOptions.SO_RCVBUF, Integer.valueOf(size));
}
/**
* Sets the {@link SocketOptions#SO_TIMEOUT read timeout} in milliseconds for this socket.
* This receive timeout defines the period the socket will block waiting to
* receive data before throwing an {@code InterruptedIOException}. The value
* {@code 0} (default) is used to set an infinite timeout. To have effect
* this option must be set before the blocking method was called.
*
* @param timeout the timeout in milliseconds or 0 for no timeout.
* @throws SocketException
* if an error occurs while setting the option.
*/
public synchronized void setSoTimeout(int timeout) throws SocketException {
if (timeout < 0) {
throw new IllegalArgumentException("timeout < 0");
}
checkOpen();
impl.setOption(SocketOptions.SO_TIMEOUT, Integer.valueOf(timeout));
}
/**
* Sets the socket implementation factory. This may only be invoked once
* over the lifetime of the application. This factory is used to create
* a new datagram socket implementation.
*
* @param fac
* the socket factory to use.
* @throws IOException
* if the factory has already been set.
* @see DatagramSocketImplFactory
*/
public static synchronized void setDatagramSocketImplFactory(DatagramSocketImplFactory fac)
throws IOException {
if (factory != null) {
throw new SocketException("Factory already set");
}
factory = fac;
}
/**
* Constructs a new {@code DatagramSocket} using the specific datagram
* socket implementation {@code socketImpl}. The created {@code
* DatagramSocket} will not be bound.
*
* @param socketImpl
* the DatagramSocketImpl to use.
*/
protected DatagramSocket(DatagramSocketImpl socketImpl) {
if (socketImpl == null) {
throw new NullPointerException("socketImpl == null");
}
impl = socketImpl;
}
/**
* Constructs a new {@code DatagramSocket} bound to the host/port specified
* by the {@code SocketAddress} {@code localAddr} or an unbound {@code
* DatagramSocket} if the {@code SocketAddress} is {@code null}.
*
* @param localAddr
* the local machine address and port to bind to.
* @throws IllegalArgumentException
* if the SocketAddress is not supported
* @throws SocketException
* if a problem occurs creating or binding the socket.
*/
public DatagramSocket(SocketAddress localAddr) throws SocketException {
if (localAddr != null) {
if (!(localAddr instanceof InetSocketAddress)) {
throw new IllegalArgumentException("Local address not an InetSocketAddress: " +
localAddr.getClass());
}
checkPort(((InetSocketAddress) localAddr).getPort());
}
impl = factory != null ? factory.createDatagramSocketImpl()
: new PlainDatagramSocketImpl();
impl.create();
if (localAddr != null) {
try {
bind(localAddr);
} catch (SocketException e) {
close();
throw e;
}
}
// SocketOptions.SO_BROADCAST is set by default for DatagramSocket
setBroadcast(true);
}
void checkOpen() throws SocketException {
if (isClosed()) {
throw new SocketException("Socket is closed");
}
}
private void ensureBound() throws SocketException {
if (!isBound()) {
impl.bind(0, Inet4Address.ANY);
isBound = true;
}
}
/**
* Binds this socket to the local address and port specified by {@code
* localAddr}. If this value is {@code null} any free port on a valid local
* address is used.
*
* @param localAddr
* the local machine address and port to bind on.
* @throws IllegalArgumentException
* if the SocketAddress is not supported
* @throws SocketException
* if the socket is already bound or a problem occurs during
* binding.
*/
public void bind(SocketAddress localAddr) throws SocketException {
checkOpen();
int localPort = 0;
InetAddress addr = Inet4Address.ANY;
if (localAddr != null) {
if (!(localAddr instanceof InetSocketAddress)) {
throw new IllegalArgumentException("Local address not an InetSocketAddress: " +
localAddr.getClass());
}
InetSocketAddress inetAddr = (InetSocketAddress) localAddr;
addr = inetAddr.getAddress();
if (addr == null) {
throw new SocketException("Host is unresolved: " + inetAddr.getHostName());
}
localPort = inetAddr.getPort();
checkPort(localPort);
}
impl.bind(localPort, addr);
isBound = true;
}
/**
* Connects this datagram socket to the address and port specified by {@code peer}.
* Future calls to {@link #send} will use this as the default target, and {@link #receive}
* will only accept packets from this source.
*
* @throws SocketException if an error occurs.
*/
public void connect(SocketAddress peer) throws SocketException {
if (peer == null) {
throw new IllegalArgumentException("peer == null");
}
if (!(peer instanceof InetSocketAddress)) {
throw new IllegalArgumentException("peer not an InetSocketAddress: " + peer.getClass());
}
InetSocketAddress isa = (InetSocketAddress) peer;
if (isa.getAddress() == null) {
throw new SocketException("Host is unresolved: " + isa.getHostName());
}
synchronized (lock) {
checkOpen();
ensureBound();
this.address = isa.getAddress();
this.port = isa.getPort();
this.isConnected = true;
impl.connect(address, port);
}
}
/**
* Connects this datagram socket to the specific {@code address} and {@code port}.
* Future calls to {@link #send} will use this as the default target, and {@link #receive}
* will only accept packets from this source.
*
* Beware: because it can't throw, this method silently ignores failures.
* Use {@link #connect(SocketAddress)} instead.
*/
public void connect(InetAddress address, int port) {
if (address == null) {
throw new IllegalArgumentException("address == null");
}
try {
connect(new InetSocketAddress(address, port));
} catch (SocketException connectException) {
// TODO: or just use SneakyThrow? There's a clear API bug here.
pendingConnectException = connectException;
}
}
/**
* Returns true if this socket is bound to a local address. See {@link #bind}.
*/
public boolean isBound() {
return isBound;
}
/**
* Returns true if this datagram socket is connected to a remote address. See {@link #connect}.
*/
public boolean isConnected() {
return isConnected;
}
/**
* Returns the {@code SocketAddress} this socket is connected to, or null for an unconnected
* socket.
*/
public SocketAddress getRemoteSocketAddress() {
if (!isConnected()) {
return null;
}
return new InetSocketAddress(getInetAddress(), getPort());
}
/**
* Returns the {@code SocketAddress} this socket is bound to, or null for an unbound socket.
*/
public SocketAddress getLocalSocketAddress() {
if (!isBound()) {
return null;
}
return new InetSocketAddress(getLocalAddress(), getLocalPort());
}
/**
* Sets the socket option {@code SocketOptions.SO_REUSEADDR}. This option
* has to be enabled if more than one UDP socket wants to be bound to the
* same address. That could be needed for receiving multicast packets.
*
* There is an undefined behavior if this option is set after the socket is
* already bound.
*
* @param reuse
* the socket option value to enable or disable this option.
* @throws SocketException
* if the socket is closed or the option could not be set.
*/
public void setReuseAddress(boolean reuse) throws SocketException {
checkOpen();
impl.setOption(SocketOptions.SO_REUSEADDR, Boolean.valueOf(reuse));
}
/**
* Gets the state of the socket option {@code SocketOptions.SO_REUSEADDR}.
*
* @return {@code true} if the option is enabled, {@code false} otherwise.
* @throws SocketException
* if the socket is closed or the option is invalid.
*/
public boolean getReuseAddress() throws SocketException {
checkOpen();
return ((Boolean) impl.getOption(SocketOptions.SO_REUSEADDR)).booleanValue();
}
/**
* Sets the socket option {@code SocketOptions.SO_BROADCAST}. This option
* must be enabled to send broadcast messages.
*
* @param broadcast
* the socket option value to enable or disable this option.
* @throws SocketException
* if the socket is closed or the option could not be set.
*/
public void setBroadcast(boolean broadcast) throws SocketException {
checkOpen();
impl.setOption(SocketOptions.SO_BROADCAST, Boolean.valueOf(broadcast));
}
/**
* Gets the state of the socket option {@code SocketOptions.SO_BROADCAST}.
*
* @return {@code true} if the option is enabled, {@code false} otherwise.
* @throws SocketException
* if the socket is closed or the option is invalid.
*/
public boolean getBroadcast() throws SocketException {
checkOpen();
return ((Boolean) impl.getOption(SocketOptions.SO_BROADCAST)).booleanValue();
}
/**
* Sets the {@see SocketOptions#IP_TOS} value for every packet sent by this socket.
*
* @throws SocketException
* if the socket is closed or the option could not be set.
*/
public void setTrafficClass(int value) throws SocketException {
checkOpen();
if (value < 0 || value > 255) {
throw new IllegalArgumentException("Value doesn't fit in an unsigned byte: " + value);
}
impl.setOption(SocketOptions.IP_TOS, Integer.valueOf(value));
}
/**
* Returns this socket's {@see SocketOptions#IP_TOS} setting.
*
* @throws SocketException
* if the socket is closed or the option is invalid.
*/
public int getTrafficClass() throws SocketException {
checkOpen();
return (Integer) impl.getOption(SocketOptions.IP_TOS);
}
/**
* Gets the state of this socket.
*
* @return {@code true} if the socket is closed, {@code false} otherwise.
*/
public boolean isClosed() {
return isClosed;
}
/**
* Returns this socket's {@code DatagramChannel}, if one exists. A channel is
* available only if this socket wraps a channel. (That is, you can go from a
* channel to a socket and back again, but you can't go from an arbitrary socket to a channel.)
* In practice, this means that the socket must have been created by
* {@link java.nio.channels.DatagramChannel#open}.
*/
public DatagramChannel getChannel() {
return null;
}
/**
* @hide internal use only
*/
public final FileDescriptor getFileDescriptor$() {
return impl.fd;
}
}