jdk/src/java.base/share/classes/java/net/AbstractPlainSocketImpl.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package java.net;

 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.FileDescriptor;

 import sun.net.ConnectionResetException;
 import sun.net.NetHooks;
 import sun.net.ResourceManager;
 import java.util.Set;
 import java.util.HashSet;
 import java.util.Collections;

 /**
  * Default Socket Implementation. This implementation does
  * not implement any security checks.
  * Note this class should <b>NOT</b> be public.
  *
  * @author  Steven B. Byrne
  */
 abstract class AbstractPlainSocketImpl extends SocketImpl
 {
     /* instance variable for SO_TIMEOUT */
     int timeout;   // timeout in millisec
     // traffic class
     private int trafficClass;

     private boolean shut_rd = false;
     private boolean shut_wr = false;

     private SocketInputStream socketInputStream = null;
     private SocketOutputStream socketOutputStream = null;

     /* number of threads using the FileDescriptor */
     protected int fdUseCount = 0;

     /* lock when increment/decrementing fdUseCount */
     protected final Object fdLock = new Object();

     /* indicates a close is pending on the file descriptor */
     protected boolean closePending = false;

     /* indicates connection reset state */
     private int CONNECTION_NOT_RESET = 0;
     private int CONNECTION_RESET_PENDING = 1;
     private int CONNECTION_RESET = 2;
     private int resetState;
     private final Object resetLock = new Object();

    /* whether this Socket is a stream (TCP) socket or not (UDP)
     */
     protected boolean stream;

     /**
      * Load net library into runtime.
      */
     static {
         java.security.AccessController.doPrivileged(
             new java.security.PrivilegedAction<>() {
                 public Void run() {
                     System.loadLibrary("net");
                     return null;
                 }
             });
     }

     private static volatile boolean checkedReusePort;
     private static volatile boolean isReusePortAvailable;

     /**
      * Tells whether SO_REUSEPORT is supported.
      */
     static boolean isReusePortAvailable() {
         if (!checkedReusePort) {
             isReusePortAvailable = isReusePortAvailable0();
             checkedReusePort = true;
         }
         return isReusePortAvailable;
     }

     /**
      * Returns a set of SocketOptions supported by this impl and by this impl's
      * socket (Socket or ServerSocket)
      *
      * @return a Set of SocketOptions
      */
     @Override
     protected Set<SocketOption<?>> supportedOptions() {
         Set<SocketOption<?>> options;
         if (isReusePortAvailable()) {
             options = new HashSet<>();
             options.addAll(super.supportedOptions());
             options.add(StandardSocketOptions.SO_REUSEPORT);
             options = Collections.unmodifiableSet(options);
         } else {
             options = super.supportedOptions();
         }
         return options;
     }

     /**
      * Creates a socket with a boolean that specifies whether this
      * is a stream socket (true) or an unconnected UDP socket (false).
      */
     protected synchronized void create(boolean stream) throws IOException {
         this.stream = stream;
         if (!stream) {
             ResourceManager.beforeUdpCreate();
             // only create the fd after we know we will be able to create the socket
             fd = new FileDescriptor();
             try {
                 socketCreate(false);
             } catch (IOException ioe) {
                 ResourceManager.afterUdpClose();
                 fd = null;
                 throw ioe;
             }
         } else {
             fd = new FileDescriptor();
             socketCreate(true);
         }
         if (socket != null)
             socket.setCreated();
         if (serverSocket != null)
             serverSocket.setCreated();
     }

     /**
      * Creates a socket and connects it to the specified port on
      * the specified host.
      * @param host the specified host
      * @param port the specified port
      */
     protected void connect(String host, int port)
         throws UnknownHostException, IOException
     {
         boolean connected = false;
         try {
             InetAddress address = InetAddress.getByName(host);
             this.port = port;
             this.address = address;

             connectToAddress(address, port, timeout);
             connected = true;
         } finally {
             if (!connected) {
                 try {
                     close();
                 } catch (IOException ioe) {
                     /* Do nothing. If connect threw an exception then
                        it will be passed up the call stack */
                 }
             }
         }
     }

     /**
      * Creates a socket and connects it to the specified address on
      * the specified port.
      * @param address the address
      * @param port the specified port
      */
     protected void connect(InetAddress address, int port) throws IOException {
         this.port = port;
         this.address = address;

         try {
             connectToAddress(address, port, timeout);
             return;
         } catch (IOException e) {
             // everything failed
             close();
             throw e;
         }
     }

     /**
      * Creates a socket and connects it to the specified address on
      * the specified port.
      * @param address the address
      * @param timeout the timeout value in milliseconds, or zero for no timeout.
      * @throws IOException if connection fails
      * @throws  IllegalArgumentException if address is null or is a
      *          SocketAddress subclass not supported by this socket
      * @since 1.4
      */
     protected void connect(SocketAddress address, int timeout)
             throws IOException {
         boolean connected = false;
         try {
             if (address == null || !(address instanceof InetSocketAddress))
                 throw new IllegalArgumentException("unsupported address type");
             InetSocketAddress addr = (InetSocketAddress) address;
             if (addr.isUnresolved())
                 throw new UnknownHostException(addr.getHostName());
             this.port = addr.getPort();
             this.address = addr.getAddress();

             connectToAddress(this.address, port, timeout);
             connected = true;
         } finally {
             if (!connected) {
                 try {
                     close();
                 } catch (IOException ioe) {
                     /* Do nothing. If connect threw an exception then
                        it will be passed up the call stack */
                 }
             }
         }
     }

     private void connectToAddress(InetAddress address, int port, int timeout) throws IOException {
         if (address.isAnyLocalAddress()) {
             doConnect(InetAddress.getLocalHost(), port, timeout);
         } else {
             doConnect(address, port, timeout);
         }
     }

     public void setOption(int opt, Object val) throws SocketException {
         if (isClosedOrPending()) {
             throw new SocketException("Socket Closed");
         }
         boolean on = true;
         switch (opt) {
             /* check type safety b4 going native.  These should never
              * fail, since only java.Socket* has access to
              * PlainSocketImpl.setOption().
              */
         case SO_LINGER:
             if (val == null || (!(val instanceof Integer) && !(val instanceof Boolean)))
                 throw new SocketException("Bad parameter for option");
             if (val instanceof Boolean) {
                 /* true only if disabling - enabling should be Integer */
                 on = false;
             }
             break;
         case SO_TIMEOUT:
             if (val == null || (!(val instanceof Integer)))
                 throw new SocketException("Bad parameter for SO_TIMEOUT");
             int tmp = ((Integer) val).intValue();
             if (tmp < 0)
                 throw new IllegalArgumentException("timeout < 0");
             timeout = tmp;
             break;
         case IP_TOS:
              if (val == null || !(val instanceof Integer)) {
                  throw new SocketException("bad argument for IP_TOS");
              }
              trafficClass = ((Integer)val).intValue();
              break;
         case SO_BINDADDR:
             throw new SocketException("Cannot re-bind socket");
         case TCP_NODELAY:
             if (val == null || !(val instanceof Boolean))
                 throw new SocketException("bad parameter for TCP_NODELAY");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_SNDBUF:
         case SO_RCVBUF:
             if (val == null || !(val instanceof Integer) ||
                 !(((Integer)val).intValue() > 0)) {
                 throw new SocketException("bad parameter for SO_SNDBUF " +
                                           "or SO_RCVBUF");
             }
             break;
         case SO_KEEPALIVE:
             if (val == null || !(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_KEEPALIVE");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_OOBINLINE:
             if (val == null || !(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_OOBINLINE");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_REUSEADDR:
             if (val == null || !(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_REUSEADDR");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_REUSEPORT:
             if (val == null || !(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_REUSEPORT");
             if (!supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT))
                 throw new UnsupportedOperationException("unsupported option");
             on = ((Boolean)val).booleanValue();
             break;
         default:
             throw new SocketException("unrecognized TCP option: " + opt);
         }
         socketSetOption(opt, on, val);
     }
     public Object getOption(int opt) throws SocketException {
         if (isClosedOrPending()) {
             throw new SocketException("Socket Closed");
         }
         if (opt == SO_TIMEOUT) {
             return timeout;
         }
         int ret = 0;
         /*
          * The native socketGetOption() knows about 3 options.
          * The 32 bit value it returns will be interpreted according
          * to what we're asking.  A return of -1 means it understands
          * the option but its turned off.  It will raise a SocketException
          * if "opt" isn't one it understands.
          */

         switch (opt) {
         case TCP_NODELAY:
             ret = socketGetOption(opt, null);
             return Boolean.valueOf(ret != -1);
         case SO_OOBINLINE:
             ret = socketGetOption(opt, null);
             return Boolean.valueOf(ret != -1);
         case SO_LINGER:
             ret = socketGetOption(opt, null);
             return (ret == -1) ? Boolean.FALSE: (Object)(ret);
         case SO_REUSEADDR:
             ret = socketGetOption(opt, null);
             return Boolean.valueOf(ret != -1);
         case SO_BINDADDR:
             InetAddressContainer in = new InetAddressContainer();
             ret = socketGetOption(opt, in);
             return in.addr;
         case SO_SNDBUF:
         case SO_RCVBUF:
             ret = socketGetOption(opt, null);
             return ret;
         case IP_TOS:
             try {
                 ret = socketGetOption(opt, null);
                 if (ret == -1) { // ipv6 tos
                     return trafficClass;
                 } else {
                     return ret;
                 }
             } catch (SocketException se) {
                     // TODO - should make better effort to read TOS or TCLASS
                     return trafficClass; // ipv6 tos
             }
         case SO_KEEPALIVE:
             ret = socketGetOption(opt, null);
             return Boolean.valueOf(ret != -1);
         case SO_REUSEPORT:
             if (!supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT)) {
                 throw new UnsupportedOperationException("unsupported option");
             }
             ret = socketGetOption(opt, null);
             return Boolean.valueOf(ret != -1);
         // should never get here
         default:
             return null;
         }
     }

     /**
      * The workhorse of the connection operation.  Tries several times to
      * establish a connection to the given <host, port>.  If unsuccessful,
      * throws an IOException indicating what went wrong.
      */

     synchronized void doConnect(InetAddress address, int port, int timeout) throws IOException {
         synchronized (fdLock) {
             if (!closePending && (socket == null || !socket.isBound())) {
                 NetHooks.beforeTcpConnect(fd, address, port);
             }
         }
         try {
             acquireFD();
             try {
                 socketConnect(address, port, timeout);
                 /* socket may have been closed during poll/select */
                 synchronized (fdLock) {
                     if (closePending) {
                         throw new SocketException ("Socket closed");
                     }
                 }
                 // If we have a ref. to the Socket, then sets the flags
                 // created, bound & connected to true.
                 // This is normally done in Socket.connect() but some
                 // subclasses of Socket may call impl.connect() directly!
                 if (socket != null) {
                     socket.setBound();
                     socket.setConnected();
                 }
             } finally {
                 releaseFD();
             }
         } catch (IOException e) {
             close();
             throw e;
         }
     }

     /**
      * Binds the socket to the specified address of the specified local port.
      * @param address the address
      * @param lport the port
      */
     protected synchronized void bind(InetAddress address, int lport)
         throws IOException
     {
        synchronized (fdLock) {
             if (!closePending && (socket == null || !socket.isBound())) {
                 NetHooks.beforeTcpBind(fd, address, lport);
             }
         }
         socketBind(address, lport);
         if (socket != null)
             socket.setBound();
         if (serverSocket != null)
             serverSocket.setBound();
     }

     /**
      * Listens, for a specified amount of time, for connections.
      * @param count the amount of time to listen for connections
      */
     protected synchronized void listen(int count) throws IOException {
         socketListen(count);
     }

     /**
      * Accepts connections.
      * @param s the connection
      */
     protected void accept(SocketImpl s) throws IOException {
         acquireFD();
         try {
             socketAccept(s);
         } finally {
             releaseFD();
         }
     }

     /**
      * Gets an InputStream for this socket.
      */
     protected synchronized InputStream getInputStream() throws IOException {
         synchronized (fdLock) {
             if (isClosedOrPending())
                 throw new IOException("Socket Closed");
             if (shut_rd)
                 throw new IOException("Socket input is shutdown");
             if (socketInputStream == null)
                 socketInputStream = new SocketInputStream(this);
         }
         return socketInputStream;
     }

     void setInputStream(SocketInputStream in) {
         socketInputStream = in;
     }

     /**
      * Gets an OutputStream for this socket.
      */
     protected synchronized OutputStream getOutputStream() throws IOException {
         synchronized (fdLock) {
             if (isClosedOrPending())
                 throw new IOException("Socket Closed");
             if (shut_wr)
                 throw new IOException("Socket output is shutdown");
             if (socketOutputStream == null)
                 socketOutputStream = new SocketOutputStream(this);
         }
         return socketOutputStream;
     }

     void setFileDescriptor(FileDescriptor fd) {
         this.fd = fd;
     }

     void setAddress(InetAddress address) {
         this.address = address;
     }

     void setPort(int port) {
         this.port = port;
     }

     void setLocalPort(int localport) {
         this.localport = localport;
     }

     /**
      * Returns the number of bytes that can be read without blocking.
      */
     protected synchronized int available() throws IOException {
         if (isClosedOrPending()) {
             throw new IOException("Stream closed.");
         }

         /*
          * If connection has been reset or shut down for input, then return 0
          * to indicate there are no buffered bytes.
          */
         if (isConnectionReset() || shut_rd) {
             return 0;
         }

         /*
          * If no bytes available and we were previously notified
          * of a connection reset then we move to the reset state.
          *
          * If are notified of a connection reset then check
          * again if there are bytes buffered on the socket.
          */
         int n = 0;
         try {
             n = socketAvailable();
             if (n == 0 && isConnectionResetPending()) {
                 setConnectionReset();
             }
         } catch (ConnectionResetException exc1) {
             setConnectionResetPending();
             try {
                 n = socketAvailable();
                 if (n == 0) {
                     setConnectionReset();
                 }
             } catch (ConnectionResetException exc2) {
             }
         }
         return n;
     }

     /**
      * Closes the socket.
      */
     protected void close() throws IOException {
         synchronized(fdLock) {
             if (fd != null) {
                 if (!stream) {
                     ResourceManager.afterUdpClose();
                 }
                 if (fdUseCount == 0) {
                     if (closePending) {
                         return;
                     }
                     closePending = true;
                     /*
                      * We close the FileDescriptor in two-steps - first the
                      * "pre-close" which closes the socket but doesn't
                      * release the underlying file descriptor. This operation
                      * may be lengthy due to untransmitted data and a long
                      * linger interval. Once the pre-close is done we do the
                      * actual socket to release the fd.
                      */
                     try {
                         socketPreClose();
                     } finally {
                         socketClose();
                     }
                     fd = null;
                     return;
                 } else {
                     /*
                      * If a thread has acquired the fd and a close
                      * isn't pending then use a deferred close.
                      * Also decrement fdUseCount to signal the last
                      * thread that releases the fd to close it.
                      */
                     if (!closePending) {
                         closePending = true;
                         fdUseCount--;
                         socketPreClose();
                     }
                 }
             }
         }
     }

     void reset() throws IOException {
         if (fd != null) {
             socketClose();
         }
         fd = null;
         super.reset();
     }


     /**
      * Shutdown read-half of the socket connection;
      */
     protected void shutdownInput() throws IOException {
       if (fd != null) {
           socketShutdown(SHUT_RD);
           if (socketInputStream != null) {
               socketInputStream.setEOF(true);
           }
           shut_rd = true;
       }
     }

     /**
      * Shutdown write-half of the socket connection;
      */
     protected void shutdownOutput() throws IOException {
       if (fd != null) {
           socketShutdown(SHUT_WR);
           shut_wr = true;
       }
     }

     protected boolean supportsUrgentData () {
         return true;
     }

     protected void sendUrgentData (int data) throws IOException {
         if (fd == null) {
             throw new IOException("Socket Closed");
         }
         socketSendUrgentData (data);
     }

     /**
      * Cleans up if the user forgets to close it.
      */
     @SuppressWarnings("deprecation")
     protected void finalize() throws IOException {
         close();
     }

     /*
      * "Acquires" and returns the FileDescriptor for this impl
      *
      * A corresponding releaseFD is required to "release" the
      * FileDescriptor.
      */
     FileDescriptor acquireFD() {
         synchronized (fdLock) {
             fdUseCount++;
             return fd;
         }
     }

     /*
      * "Release" the FileDescriptor for this impl.
      *
      * If the use count goes to -1 then the socket is closed.
      */
     void releaseFD() {
         synchronized (fdLock) {
             fdUseCount--;
             if (fdUseCount == -1) {
                 if (fd != null) {
                     try {
                         socketClose();
                     } catch (IOException e) {
                     } finally {
                         fd = null;
                     }
                 }
             }
         }
     }

     public boolean isConnectionReset() {
         synchronized (resetLock) {
             return (resetState == CONNECTION_RESET);
         }
     }

     public boolean isConnectionResetPending() {
         synchronized (resetLock) {
             return (resetState == CONNECTION_RESET_PENDING);
         }
     }

     public void setConnectionReset() {
         synchronized (resetLock) {
             resetState = CONNECTION_RESET;
         }
     }

     public void setConnectionResetPending() {
         synchronized (resetLock) {
             if (resetState == CONNECTION_NOT_RESET) {
                 resetState = CONNECTION_RESET_PENDING;
             }
         }

     }

     /*
      * Return true if already closed or close is pending
      */
     public boolean isClosedOrPending() {
         /*
          * Lock on fdLock to ensure that we wait if a
          * close is in progress.
          */
         synchronized (fdLock) {
             if (closePending || (fd == null)) {
                 return true;
             } else {
                 return false;
             }
         }
     }

     /*
      * Return the current value of SO_TIMEOUT
      */
     public int getTimeout() {
         return timeout;
     }

     /*
      * "Pre-close" a socket by dup'ing the file descriptor - this enables
      * the socket to be closed without releasing the file descriptor.
      */
     private void socketPreClose() throws IOException {
         socketClose0(true);
     }

     /*
      * Close the socket (and release the file descriptor).
      */
     protected void socketClose() throws IOException {
         socketClose0(false);
     }

     abstract void socketCreate(boolean isServer) throws IOException;
     abstract void socketConnect(InetAddress address, int port, int timeout)
         throws IOException;
     abstract void socketBind(InetAddress address, int port)
         throws IOException;
     abstract void socketListen(int count)
         throws IOException;
     abstract void socketAccept(SocketImpl s)
         throws IOException;
     abstract int socketAvailable()
         throws IOException;
     abstract void socketClose0(boolean useDeferredClose)
         throws IOException;
     abstract void socketShutdown(int howto)
         throws IOException;
     abstract void socketSetOption(int cmd, boolean on, Object value)
         throws SocketException;
     abstract int socketGetOption(int opt, Object iaContainerObj) throws SocketException;
     abstract void socketSendUrgentData(int data)
         throws IOException;

     public static final int SHUT_RD = 0;
     public static final int SHUT_WR = 1;

     private static native boolean isReusePortAvailable0();
 }
	/*
	* Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.net;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.io.FileDescriptor;

	import sun.net.ConnectionResetException;
	import sun.net.NetHooks;
	import sun.net.ResourceManager;
	import java.util.Set;
	import java.util.HashSet;
	import java.util.Collections;

	/**
	* Default Socket Implementation. This implementation does
	* not implement any security checks.
	* Note this class should <b>NOT</b> be public.
	*
	* @author Steven B. Byrne
	*/
	abstract class AbstractPlainSocketImpl extends SocketImpl
	{
	/* instance variable for SO_TIMEOUT */
	int timeout; // timeout in millisec
	// traffic class
	private int trafficClass;

	private boolean shut_rd = false;
	private boolean shut_wr = false;

	private SocketInputStream socketInputStream = null;
	private SocketOutputStream socketOutputStream = null;

	/* number of threads using the FileDescriptor */
	protected int fdUseCount = 0;

	/* lock when increment/decrementing fdUseCount */
	protected final Object fdLock = new Object();

	/* indicates a close is pending on the file descriptor */
	protected boolean closePending = false;

	/* indicates connection reset state */
	private int CONNECTION_NOT_RESET = 0;
	private int CONNECTION_RESET_PENDING = 1;
	private int CONNECTION_RESET = 2;
	private int resetState;
	private final Object resetLock = new Object();

	/* whether this Socket is a stream (TCP) socket or not (UDP)
	*/
	protected boolean stream;

	/**
	* Load net library into runtime.
	*/
	static {
	java.security.AccessController.doPrivileged(
	new java.security.PrivilegedAction<>() {
	public Void run() {
	System.loadLibrary("net");
	return null;
	}
	});
	}

	private static volatile boolean checkedReusePort;
	private static volatile boolean isReusePortAvailable;

	/**
	* Tells whether SO_REUSEPORT is supported.
	*/
	static boolean isReusePortAvailable() {
	if (!checkedReusePort) {
	isReusePortAvailable = isReusePortAvailable0();
	checkedReusePort = true;
	}
	return isReusePortAvailable;
	}

	/**
	* Returns a set of SocketOptions supported by this impl and by this impl's
	* socket (Socket or ServerSocket)
	*
	* @return a Set of SocketOptions
	*/
	@Override
	protected Set<SocketOption<?>> supportedOptions() {
	Set<SocketOption<?>> options;
	if (isReusePortAvailable()) {
	options = new HashSet<>();
	options.addAll(super.supportedOptions());
	options.add(StandardSocketOptions.SO_REUSEPORT);
	options = Collections.unmodifiableSet(options);
	} else {
	options = super.supportedOptions();
	}
	return options;
	}

	/**
	* Creates a socket with a boolean that specifies whether this
	* is a stream socket (true) or an unconnected UDP socket (false).
	*/
	protected synchronized void create(boolean stream) throws IOException {
	this.stream = stream;
	if (!stream) {
	ResourceManager.beforeUdpCreate();
	// only create the fd after we know we will be able to create the socket
	fd = new FileDescriptor();
	try {
	socketCreate(false);
	} catch (IOException ioe) {
	ResourceManager.afterUdpClose();
	fd = null;
	throw ioe;
	}
	} else {
	fd = new FileDescriptor();
	socketCreate(true);
	}
	if (socket != null)
	socket.setCreated();
	if (serverSocket != null)
	serverSocket.setCreated();
	}

	/**
	* Creates a socket and connects it to the specified port on
	* the specified host.
	* @param host the specified host
	* @param port the specified port
	*/
	protected void connect(String host, int port)
	throws UnknownHostException, IOException
	{
	boolean connected = false;
	try {
	InetAddress address = InetAddress.getByName(host);
	this.port = port;
	this.address = address;

	connectToAddress(address, port, timeout);
	connected = true;
	} finally {
	if (!connected) {
	try {
	close();
	} catch (IOException ioe) {
	/* Do nothing. If connect threw an exception then
	it will be passed up the call stack */
	}
	}
	}
	}

	/**
	* Creates a socket and connects it to the specified address on
	* the specified port.
	* @param address the address
	* @param port the specified port
	*/
	protected void connect(InetAddress address, int port) throws IOException {
	this.port = port;
	this.address = address;

	try {
	connectToAddress(address, port, timeout);
	return;
	} catch (IOException e) {
	// everything failed
	close();
	throw e;
	}
	}

	/**
	* Creates a socket and connects it to the specified address on
	* the specified port.
	* @param address the address
	* @param timeout the timeout value in milliseconds, or zero for no timeout.
	* @throws IOException if connection fails
	* @throws IllegalArgumentException if address is null or is a
	* SocketAddress subclass not supported by this socket
	* @since 1.4
	*/
	protected void connect(SocketAddress address, int timeout)
	throws IOException {
	boolean connected = false;
	try {
	if (address == null \|\| !(address instanceof InetSocketAddress))
	throw new IllegalArgumentException("unsupported address type");
	InetSocketAddress addr = (InetSocketAddress) address;
	if (addr.isUnresolved())
	throw new UnknownHostException(addr.getHostName());
	this.port = addr.getPort();
	this.address = addr.getAddress();

	connectToAddress(this.address, port, timeout);
	connected = true;
	} finally {
	if (!connected) {
	try {
	close();
	} catch (IOException ioe) {
	/* Do nothing. If connect threw an exception then
	it will be passed up the call stack */
	}
	}
	}
	}

	private void connectToAddress(InetAddress address, int port, int timeout) throws IOException {
	if (address.isAnyLocalAddress()) {
	doConnect(InetAddress.getLocalHost(), port, timeout);
	} else {
	doConnect(address, port, timeout);
	}
	}

	public void setOption(int opt, Object val) throws SocketException {
	if (isClosedOrPending()) {
	throw new SocketException("Socket Closed");
	}
	boolean on = true;
	switch (opt) {
	/* check type safety b4 going native. These should never
	* fail, since only java.Socket* has access to
	* PlainSocketImpl.setOption().
	*/
	case SO_LINGER:
	if (val == null \|\| (!(val instanceof Integer) && !(val instanceof Boolean)))
	throw new SocketException("Bad parameter for option");
	if (val instanceof Boolean) {
	/* true only if disabling - enabling should be Integer */
	on = false;
	}
	break;
	case SO_TIMEOUT:
	if (val == null \|\| (!(val instanceof Integer)))
	throw new SocketException("Bad parameter for SO_TIMEOUT");
	int tmp = ((Integer) val).intValue();
	if (tmp < 0)
	throw new IllegalArgumentException("timeout < 0");
	timeout = tmp;
	break;
	case IP_TOS:
	if (val == null \|\| !(val instanceof Integer)) {
	throw new SocketException("bad argument for IP_TOS");
	}
	trafficClass = ((Integer)val).intValue();
	break;
	case SO_BINDADDR:
	throw new SocketException("Cannot re-bind socket");
	case TCP_NODELAY:
	if (val == null \|\| !(val instanceof Boolean))
	throw new SocketException("bad parameter for TCP_NODELAY");
	on = ((Boolean)val).booleanValue();
	break;
	case SO_SNDBUF:
	case SO_RCVBUF:
	if (val == null \|\| !(val instanceof Integer) \|\|
	!(((Integer)val).intValue() > 0)) {
	throw new SocketException("bad parameter for SO_SNDBUF " +
	"or SO_RCVBUF");
	}
	break;
	case SO_KEEPALIVE:
	if (val == null \|\| !(val instanceof Boolean))
	throw new SocketException("bad parameter for SO_KEEPALIVE");
	on = ((Boolean)val).booleanValue();
	break;
	case SO_OOBINLINE:
	if (val == null \|\| !(val instanceof Boolean))
	throw new SocketException("bad parameter for SO_OOBINLINE");
	on = ((Boolean)val).booleanValue();
	break;
	case SO_REUSEADDR:
	if (val == null \|\| !(val instanceof Boolean))
	throw new SocketException("bad parameter for SO_REUSEADDR");
	on = ((Boolean)val).booleanValue();
	break;
	case SO_REUSEPORT:
	if (val == null \|\| !(val instanceof Boolean))
	throw new SocketException("bad parameter for SO_REUSEPORT");
	if (!supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT))
	throw new UnsupportedOperationException("unsupported option");
	on = ((Boolean)val).booleanValue();
	break;
	default:
	throw new SocketException("unrecognized TCP option: " + opt);
	}
	socketSetOption(opt, on, val);
	}
	public Object getOption(int opt) throws SocketException {
	if (isClosedOrPending()) {
	throw new SocketException("Socket Closed");
	}
	if (opt == SO_TIMEOUT) {
	return timeout;
	}
	int ret = 0;
	/*
	* The native socketGetOption() knows about 3 options.
	* The 32 bit value it returns will be interpreted according
	* to what we're asking. A return of -1 means it understands
	* the option but its turned off. It will raise a SocketException
	* if "opt" isn't one it understands.
	*/

	switch (opt) {
	case TCP_NODELAY:
	ret = socketGetOption(opt, null);
	return Boolean.valueOf(ret != -1);
	case SO_OOBINLINE:
	ret = socketGetOption(opt, null);
	return Boolean.valueOf(ret != -1);
	case SO_LINGER:
	ret = socketGetOption(opt, null);
	return (ret == -1) ? Boolean.FALSE: (Object)(ret);
	case SO_REUSEADDR:
	ret = socketGetOption(opt, null);
	return Boolean.valueOf(ret != -1);
	case SO_BINDADDR:
	InetAddressContainer in = new InetAddressContainer();
	ret = socketGetOption(opt, in);
	return in.addr;
	case SO_SNDBUF:
	case SO_RCVBUF:
	ret = socketGetOption(opt, null);
	return ret;
	case IP_TOS:
	try {
	ret = socketGetOption(opt, null);
	if (ret == -1) { // ipv6 tos
	return trafficClass;
	} else {
	return ret;
	}
	} catch (SocketException se) {
	// TODO - should make better effort to read TOS or TCLASS
	return trafficClass; // ipv6 tos
	}
	case SO_KEEPALIVE:
	ret = socketGetOption(opt, null);
	return Boolean.valueOf(ret != -1);
	case SO_REUSEPORT:
	if (!supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT)) {
	throw new UnsupportedOperationException("unsupported option");
	}
	ret = socketGetOption(opt, null);
	return Boolean.valueOf(ret != -1);
	// should never get here
	default:
	return null;
	}
	}

	/**
	* The workhorse of the connection operation. Tries several times to
	* establish a connection to the given <host, port>. If unsuccessful,
	* throws an IOException indicating what went wrong.
	*/

	synchronized void doConnect(InetAddress address, int port, int timeout) throws IOException {
	synchronized (fdLock) {
	if (!closePending && (socket == null \|\| !socket.isBound())) {
	NetHooks.beforeTcpConnect(fd, address, port);
	}
	}
	try {
	acquireFD();
	try {
	socketConnect(address, port, timeout);
	/* socket may have been closed during poll/select */
	synchronized (fdLock) {
	if (closePending) {
	throw new SocketException ("Socket closed");
	}
	}
	// If we have a ref. to the Socket, then sets the flags
	// created, bound & connected to true.
	// This is normally done in Socket.connect() but some
	// subclasses of Socket may call impl.connect() directly!
	if (socket != null) {
	socket.setBound();
	socket.setConnected();
	}
	} finally {
	releaseFD();
	}
	} catch (IOException e) {
	close();
	throw e;
	}
	}

	/**
	* Binds the socket to the specified address of the specified local port.
	* @param address the address
	* @param lport the port
	*/
	protected synchronized void bind(InetAddress address, int lport)
	throws IOException
	{
	synchronized (fdLock) {
	if (!closePending && (socket == null \|\| !socket.isBound())) {
	NetHooks.beforeTcpBind(fd, address, lport);
	}
	}
	socketBind(address, lport);
	if (socket != null)
	socket.setBound();
	if (serverSocket != null)
	serverSocket.setBound();
	}

	/**
	* Listens, for a specified amount of time, for connections.
	* @param count the amount of time to listen for connections
	*/
	protected synchronized void listen(int count) throws IOException {
	socketListen(count);
	}

	/**
	* Accepts connections.
	* @param s the connection
	*/
	protected void accept(SocketImpl s) throws IOException {
	acquireFD();
	try {
	socketAccept(s);
	} finally {
	releaseFD();
	}
	}

	/**
	* Gets an InputStream for this socket.
	*/
	protected synchronized InputStream getInputStream() throws IOException {
	synchronized (fdLock) {
	if (isClosedOrPending())
	throw new IOException("Socket Closed");
	if (shut_rd)
	throw new IOException("Socket input is shutdown");
	if (socketInputStream == null)
	socketInputStream = new SocketInputStream(this);
	}
	return socketInputStream;
	}

	void setInputStream(SocketInputStream in) {
	socketInputStream = in;
	}

	/**
	* Gets an OutputStream for this socket.
	*/
	protected synchronized OutputStream getOutputStream() throws IOException {
	synchronized (fdLock) {
	if (isClosedOrPending())
	throw new IOException("Socket Closed");
	if (shut_wr)
	throw new IOException("Socket output is shutdown");
	if (socketOutputStream == null)
	socketOutputStream = new SocketOutputStream(this);
	}
	return socketOutputStream;
	}

	void setFileDescriptor(FileDescriptor fd) {
	this.fd = fd;
	}

	void setAddress(InetAddress address) {
	this.address = address;
	}

	void setPort(int port) {
	this.port = port;
	}

	void setLocalPort(int localport) {
	this.localport = localport;
	}

	/**
	* Returns the number of bytes that can be read without blocking.
	*/
	protected synchronized int available() throws IOException {
	if (isClosedOrPending()) {
	throw new IOException("Stream closed.");
	}

	/*
	* If connection has been reset or shut down for input, then return 0
	* to indicate there are no buffered bytes.
	*/
	if (isConnectionReset() \|\| shut_rd) {
	return 0;
	}

	/*
	* If no bytes available and we were previously notified
	* of a connection reset then we move to the reset state.
	*
	* If are notified of a connection reset then check
	* again if there are bytes buffered on the socket.
	*/
	int n = 0;
	try {
	n = socketAvailable();
	if (n == 0 && isConnectionResetPending()) {
	setConnectionReset();
	}
	} catch (ConnectionResetException exc1) {
	setConnectionResetPending();
	try {
	n = socketAvailable();
	if (n == 0) {
	setConnectionReset();
	}
	} catch (ConnectionResetException exc2) {
	}
	}
	return n;
	}

	/**
	* Closes the socket.
	*/
	protected void close() throws IOException {
	synchronized(fdLock) {
	if (fd != null) {
	if (!stream) {
	ResourceManager.afterUdpClose();
	}
	if (fdUseCount == 0) {
	if (closePending) {
	return;
	}
	closePending = true;
	/*
	* We close the FileDescriptor in two-steps - first the
	* "pre-close" which closes the socket but doesn't
	* release the underlying file descriptor. This operation
	* may be lengthy due to untransmitted data and a long
	* linger interval. Once the pre-close is done we do the
	* actual socket to release the fd.
	*/
	try {
	socketPreClose();
	} finally {
	socketClose();
	}
	fd = null;
	return;
	} else {
	/*
	* If a thread has acquired the fd and a close
	* isn't pending then use a deferred close.
	* Also decrement fdUseCount to signal the last
	* thread that releases the fd to close it.
	*/
	if (!closePending) {
	closePending = true;
	fdUseCount--;
	socketPreClose();
	}
	}
	}
	}
	}

	void reset() throws IOException {
	if (fd != null) {
	socketClose();
	}
	fd = null;
	super.reset();
	}


	/**
	* Shutdown read-half of the socket connection;
	*/
	protected void shutdownInput() throws IOException {
	if (fd != null) {
	socketShutdown(SHUT_RD);
	if (socketInputStream != null) {
	socketInputStream.setEOF(true);
	}
	shut_rd = true;
	}
	}

	/**
	* Shutdown write-half of the socket connection;
	*/
	protected void shutdownOutput() throws IOException {
	if (fd != null) {
	socketShutdown(SHUT_WR);
	shut_wr = true;
	}
	}

	protected boolean supportsUrgentData () {
	return true;
	}

	protected void sendUrgentData (int data) throws IOException {
	if (fd == null) {
	throw new IOException("Socket Closed");
	}
	socketSendUrgentData (data);
	}

	/**
	* Cleans up if the user forgets to close it.
	*/
	@SuppressWarnings("deprecation")
	protected void finalize() throws IOException {
	close();
	}

	/*
	* "Acquires" and returns the FileDescriptor for this impl
	*
	* A corresponding releaseFD is required to "release" the
	* FileDescriptor.
	*/
	FileDescriptor acquireFD() {
	synchronized (fdLock) {
	fdUseCount++;
	return fd;
	}
	}

	/*
	* "Release" the FileDescriptor for this impl.
	*
	* If the use count goes to -1 then the socket is closed.
	*/
	void releaseFD() {
	synchronized (fdLock) {
	fdUseCount--;
	if (fdUseCount == -1) {
	if (fd != null) {
	try {
	socketClose();
	} catch (IOException e) {
	} finally {
	fd = null;
	}
	}
	}
	}
	}

	public boolean isConnectionReset() {
	synchronized (resetLock) {
	return (resetState == CONNECTION_RESET);
	}
	}

	public boolean isConnectionResetPending() {
	synchronized (resetLock) {
	return (resetState == CONNECTION_RESET_PENDING);
	}
	}

	public void setConnectionReset() {
	synchronized (resetLock) {
	resetState = CONNECTION_RESET;
	}
	}

	public void setConnectionResetPending() {
	synchronized (resetLock) {
	if (resetState == CONNECTION_NOT_RESET) {
	resetState = CONNECTION_RESET_PENDING;
	}
	}

	}

	/*
	* Return true if already closed or close is pending
	*/
	public boolean isClosedOrPending() {
	/*
	* Lock on fdLock to ensure that we wait if a
	* close is in progress.
	*/
	synchronized (fdLock) {
	if (closePending \|\| (fd == null)) {
	return true;
	} else {
	return false;
	}
	}
	}

	/*
	* Return the current value of SO_TIMEOUT
	*/
	public int getTimeout() {
	return timeout;
	}

	/*
	* "Pre-close" a socket by dup'ing the file descriptor - this enables
	* the socket to be closed without releasing the file descriptor.
	*/
	private void socketPreClose() throws IOException {
	socketClose0(true);
	}

	/*
	* Close the socket (and release the file descriptor).
	*/
	protected void socketClose() throws IOException {
	socketClose0(false);
	}

	abstract void socketCreate(boolean isServer) throws IOException;
	abstract void socketConnect(InetAddress address, int port, int timeout)
	throws IOException;
	abstract void socketBind(InetAddress address, int port)
	throws IOException;
	abstract void socketListen(int count)
	throws IOException;
	abstract void socketAccept(SocketImpl s)
	throws IOException;
	abstract int socketAvailable()
	throws IOException;
	abstract void socketClose0(boolean useDeferredClose)
	throws IOException;
	abstract void socketShutdown(int howto)
	throws IOException;
	abstract void socketSetOption(int cmd, boolean on, Object value)
	throws SocketException;
	abstract int socketGetOption(int opt, Object iaContainerObj) throws SocketException;
	abstract void socketSendUrgentData(int data)
	throws IOException;

	public static final int SHUT_RD = 0;
	public static final int SHUT_WR = 1;

	private static native boolean isReusePortAvailable0();
	}