/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 *
 *
 *
 *
 */

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;

/**
 * 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<Void>() {
 public Void run() {
 System.loadLibrary("net");
 return null;
 }
 });
 }

 /**
 * 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;
 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 new Integer(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)(new Integer(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 new Integer(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);
 // 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.
 */
 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 final static int SHUT_RD = 0;
 public final static int SHUT_WR = 1;
}