Back to index...

	/*
	* Copyright (c) 1996, 2019, 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 sun.rmi.transport.tcp;

	import java.io.DataInput;
	import java.io.DataOutput;
	import java.io.IOException;
	import java.io.ObjectInput;
	import java.io.ObjectOutput;
	import java.lang.reflect.Proxy;
	import java.net.InetAddress;
	import java.net.ServerSocket;
	import java.net.Socket;
	import java.rmi.ConnectIOException;
	import java.rmi.RemoteException;
	import java.rmi.server.RMIClientSocketFactory;
	import java.rmi.server.RMIServerSocketFactory;
	import java.rmi.server.RMISocketFactory;
	import java.security.AccessController;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.LinkedList;
	import java.util.Map;
	import java.util.Set;
	import sun.rmi.runtime.Log;
	import sun.rmi.runtime.NewThreadAction;
	import sun.rmi.transport.Channel;
	import sun.rmi.transport.Endpoint;
	import sun.rmi.transport.Target;
	import sun.rmi.transport.Transport;
	import sun.security.action.GetBooleanAction;
	import sun.security.action.GetIntegerAction;
	import sun.security.action.GetPropertyAction;

	/**
	* TCPEndpoint represents some communication endpoint for an address
	* space (VM).
	*
	* @author Ann Wollrath
	*/
	public class TCPEndpoint implements Endpoint {
	/** IP address or host name */
	private String host;
	/** port number */
	private int port;
	/** custom client socket factory (null if not custom factory) */
	private final RMIClientSocketFactory csf;
	/** custom server socket factory (null if not custom factory) */
	private final RMIServerSocketFactory ssf;

	/** if local, the port number to listen on */
	private int listenPort = -1;
	/** if local, the transport object associated with this endpoint */
	private TCPTransport transport = null;

	/** the local host name */
	private static String localHost;
	/** true if real local host name is known yet */
	private static boolean localHostKnown;

	// this should be a private method since it is privileged
	private static int getInt(String name, int def) {
	return AccessController.doPrivileged(new GetIntegerAction(name, def));
	}

	// this should be a private method since it is privileged
	private static boolean getBoolean(String name) {
	return AccessController.doPrivileged(new GetBooleanAction(name));
	}

	/**
	* Returns the value of the java.rmi.server.hostname property.
	*/
	private static String getHostnameProperty() {
	return AccessController.doPrivileged(
	new GetPropertyAction("java.rmi.server.hostname"));
	}

	/**
	* Find host name of local machine. Property "java.rmi.server.hostname"
	* is used if set, so server administrator can compensate for the possible
	* inablility to get fully qualified host name from VM.
	*/
	static {
	localHostKnown = true;
	localHost = getHostnameProperty();

	// could try querying CGI program here?
	if (localHost == null) {
	try {
	InetAddress localAddr = InetAddress.getLocalHost();
	byte[] raw = localAddr.getAddress();
	if ((raw[0] == 127) &&
	(raw[1] == 0) &&
	(raw[2] == 0) &&
	(raw[3] == 1)) {
	localHostKnown = false;
	}

	/* if the user wishes to use a fully qualified domain
	* name then attempt to find one.
	*/
	if (getBoolean("java.rmi.server.useLocalHostName")) {
	localHost = FQDN.attemptFQDN(localAddr);
	} else {
	/* default to using ip addresses, names will
	* work across seperate domains.
	*/
	localHost = localAddr.getHostAddress();
	}
	} catch (Exception e) {
	localHostKnown = false;
	localHost = null;
	}
	}

	if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) {
	TCPTransport.tcpLog.log(Log.BRIEF,
	"localHostKnown = " + localHostKnown +
	", localHost = " + localHost);
	}
	}

	/** maps an endpoint key containing custom socket factories to
	* their own unique endpoint */
	// TBD: should this be a weak hash table?
	private static final
	Map<TCPEndpoint,LinkedList<TCPEndpoint>> localEndpoints =
	new HashMap<>();

	/**
	* Create an endpoint for a specified host and port.
	* This should not be used by external classes to create endpoints
	* for servers in this VM; use getLocalEndpoint instead.
	*/
	public TCPEndpoint(String host, int port) {
	this(host, port, null, null);
	}

	/**
	* Create a custom socket factory endpoint for a specified host and port.
	* This should not be used by external classes to create endpoints
	* for servers in this VM; use getLocalEndpoint instead.
	*/
	public TCPEndpoint(String host, int port, RMIClientSocketFactory csf,
	RMIServerSocketFactory ssf)
	{
	if (host == null)
	host = "";
	this.host = host;
	this.port = port;
	this.csf = csf;
	this.ssf = ssf;
	}

	/**
	* Get an endpoint for the local address space on specified port.
	* If port number is 0, it returns shared default endpoint object
	* whose host name and port may or may not have been determined.
	*/
	public static TCPEndpoint getLocalEndpoint(int port) {
	return getLocalEndpoint(port, null, null);
	}

	public static TCPEndpoint getLocalEndpoint(int port,
	RMIClientSocketFactory csf,
	RMIServerSocketFactory ssf)
	{
	/*
	* Find mapping for an endpoint key to the list of local unique
	* endpoints for this client/server socket factory pair (perhaps
	* null) for the specific port.
	*/
	TCPEndpoint ep = null;

	synchronized (localEndpoints) {
	TCPEndpoint endpointKey = new TCPEndpoint(null, port, csf, ssf);
	LinkedList<TCPEndpoint> epList = localEndpoints.get(endpointKey);
	String localHost = resampleLocalHost();

	if (epList == null) {
	/*
	* Create new endpoint list.
	*/
	ep = new TCPEndpoint(localHost, port, csf, ssf);
	epList = new LinkedList<TCPEndpoint>();
	epList.add(ep);
	ep.listenPort = port;
	ep.transport = new TCPTransport(epList);
	localEndpoints.put(endpointKey, epList);

	if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) {
	TCPTransport.tcpLog.log(Log.BRIEF,
	"created local endpoint for socket factory " + ssf +
	" on port " + port);
	}
	} else {
	synchronized (epList) {
	ep = epList.getLast();
	String lastHost = ep.host;
	int lastPort = ep.port;
	TCPTransport lastTransport = ep.transport;
	// assert (localHost == null ^ lastHost != null)
	if (localHost != null && !localHost.equals(lastHost)) {
	/*
	* Hostname has been updated; add updated endpoint
	* to list.
	*/
	if (lastPort != 0) {
	/*
	* Remove outdated endpoints only if the
	* port has already been set on those endpoints.
	*/
	epList.clear();
	}
	ep = new TCPEndpoint(localHost, lastPort, csf, ssf);
	ep.listenPort = port;
	ep.transport = lastTransport;
	epList.add(ep);
	}
	}
	}
	}

	return ep;
	}

	/**
	* Resamples the local hostname and returns the possibly-updated
	* local hostname.
	*/
	private static String resampleLocalHost() {

	String hostnameProperty = getHostnameProperty();

	synchronized (localEndpoints) {
	// assert(localHostKnown ^ (localHost == null))

	if (hostnameProperty != null) {
	if (!localHostKnown) {
	/*
	* If the local hostname is unknown, update ALL
	* existing endpoints with the new hostname.
	*/
	setLocalHost(hostnameProperty);
	} else if (!hostnameProperty.equals(localHost)) {
	/*
	* Only update the localHost field for reference
	* in future endpoint creation.
	*/
	localHost = hostnameProperty;

	if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) {
	TCPTransport.tcpLog.log(Log.BRIEF,
	"updated local hostname to: " + localHost);
	}
	}
	}
	return localHost;
	}
	}

	/**
	* Set the local host name, if currently unknown.
	*/
	static void setLocalHost(String host) {
	// assert (host != null)

	synchronized (localEndpoints) {
	/*
	* If host is not known, change the host field of ALL
	* the local endpoints.
	*/
	if (!localHostKnown) {
	localHost = host;
	localHostKnown = true;

	if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) {
	TCPTransport.tcpLog.log(Log.BRIEF,
	"local host set to " + host);
	}
	for (LinkedList<TCPEndpoint> epList : localEndpoints.values())
	{
	synchronized (epList) {
	for (TCPEndpoint ep : epList) {
	ep.host = host;
	}
	}
	}
	}
	}
	}

	/**
	* Set the port of the (shared) default endpoint object.
	* When first created, it contains port 0 because the transport
	* hasn't tried to listen to get assigned a port, or if listening
	* failed, a port hasn't been assigned from the server.
	*/
	static void setDefaultPort(int port, RMIClientSocketFactory csf,
	RMIServerSocketFactory ssf)
	{
	TCPEndpoint endpointKey = new TCPEndpoint(null, 0, csf, ssf);

	synchronized (localEndpoints) {
	LinkedList<TCPEndpoint> epList = localEndpoints.get(endpointKey);

	synchronized (epList) {
	int size = epList.size();
	TCPEndpoint lastEp = epList.getLast();

	for (TCPEndpoint ep : epList) {
	ep.port = port;
	}
	if (size > 1) {
	/*
	* Remove all but the last element of the list
	* (which contains the most recent hostname).
	*/
	epList.clear();
	epList.add(lastEp);
	}
	}

	/*
	* Allow future exports to use the actual bound port
	* explicitly (see 6269166).
	*/
	TCPEndpoint newEndpointKey = new TCPEndpoint(null, port, csf, ssf);
	localEndpoints.put(newEndpointKey, epList);

	if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) {
	TCPTransport.tcpLog.log(Log.BRIEF,
	"default port for server socket factory " + ssf +
	" and client socket factory " + csf +
	" set to " + port);
	}
	}
	}

	/**
	* Returns transport for making connections to remote endpoints;
	* (here, the default transport at port 0 is used).
	*/
	public Transport getOutboundTransport() {
	TCPEndpoint localEndpoint = getLocalEndpoint(0, null, null);
	return localEndpoint.transport;
	}

	/**
	* Returns the current list of known transports.
	* The returned list is an unshared collection of Transports,
	* including all transports which may have channels to remote
	* endpoints.
	*/
	private static Collection<TCPTransport> allKnownTransports() {
	// Loop through local endpoints, getting the transport of each one.
	Set<TCPTransport> s;
	synchronized (localEndpoints) {
	// presize s to number of localEndpoints
	s = new HashSet<TCPTransport>(localEndpoints.size());
	for (LinkedList<TCPEndpoint> epList : localEndpoints.values()) {
	/*
	* Each local endpoint has its transport added to s.
	* Note: the transport is the same for all endpoints
	* in the list, so it is okay to pick any one of them.
	*/
	TCPEndpoint ep = epList.getFirst();
	s.add(ep.transport);
	}
	}
	return s;
	}

	/**
	* Release idle outbound connections to reduce demand on I/O resources.
	* All transports are asked to release excess connections.
	*/
	public static void shedConnectionCaches() {
	for (TCPTransport transport : allKnownTransports()) {
	transport.shedConnectionCaches();
	}
	}

	/**
	* Export the object to accept incoming calls.
	*/
	public void exportObject(Target target) throws RemoteException {
	transport.exportObject(target);
	}

	/**
	* Returns a channel for this (remote) endpoint.
	*/
	public Channel getChannel() {
	return getOutboundTransport().getChannel(this);
	}

	/**
	* Returns address for endpoint
	*/
	public String getHost() {
	return host;
	}

	/**
	* Returns the port for this endpoint. If this endpoint was
	* created as a server endpoint (using getLocalEndpoint) for a
	* default/anonymous port and its inbound transport has started
	* listening, this method returns (instead of zero) the actual
	* bound port suitable for passing to clients.
	**/
	public int getPort() {
	return port;
	}

	/**
	* Returns the port that this endpoint's inbound transport listens
	* on, if this endpoint was created as a server endpoint (using
	* getLocalEndpoint). If this endpoint was created for the
	* default/anonymous port, then this method returns zero even if
	* the transport has started listening.
	**/
	public int getListenPort() {
	return listenPort;
	}

	/**
	* Returns the transport for incoming connections to this
	* endpoint, if this endpoint was created as a server endpoint
	* (using getLocalEndpoint).
	**/
	public Transport getInboundTransport() {
	return transport;
	}

	/**
	* Get the client socket factory associated with this endpoint.
	*/
	public RMIClientSocketFactory getClientSocketFactory() {
	return csf;
	}

	/**
	* Get the server socket factory associated with this endpoint.
	*/
	public RMIServerSocketFactory getServerSocketFactory() {
	return ssf;
	}

	/**
	* Return string representation for endpoint.
	*/
	public String toString() {
	return "[" + host + ":" + port +
	(ssf != null ? "," + ssf : "") +
	(csf != null ? "," + csf : "") +
	"]";
	}

	public int hashCode() {
	return port;
	}

	public boolean equals(Object obj) {
	if ((obj != null) && (obj instanceof TCPEndpoint)) {
	TCPEndpoint ep = (TCPEndpoint) obj;
	if (port != ep.port \|\| !host.equals(ep.host))
	return false;
	if (((csf == null) ^ (ep.csf == null)) \|\|
	((ssf == null) ^ (ep.ssf == null)))
	return false;
	/*
	* Fix for 4254510: perform socket factory class equality check
	* before socket factory equality check to avoid passing
	* a potentially naughty socket factory to this endpoint's
	* {client,server} socket factory equals method.
	*/
	if ((csf != null) &&
	!(csf.getClass() == ep.csf.getClass() && csf.equals(ep.csf)))
	return false;
	if ((ssf != null) &&
	!(ssf.getClass() == ep.ssf.getClass() && ssf.equals(ep.ssf)))
	return false;
	return true;
	} else {
	return false;
	}
	}

	/* codes for the self-describing formats of wire representation */
	private static final int FORMAT_HOST_PORT = 0;
	private static final int FORMAT_HOST_PORT_FACTORY = 1;

	/**
	* Write endpoint to output stream.
	*/
	public void write(ObjectOutput out) throws IOException {
	if (csf == null) {
	out.writeByte(FORMAT_HOST_PORT);
	out.writeUTF(host);
	out.writeInt(port);
	} else {
	out.writeByte(FORMAT_HOST_PORT_FACTORY);
	out.writeUTF(host);
	out.writeInt(port);
	out.writeObject(csf);
	}
	}

	/**
	* Get the endpoint from the input stream.
	* @param in the input stream
	* @exception IOException If id could not be read (due to stream failure)
	*/
	public static TCPEndpoint read(ObjectInput in)
	throws IOException, ClassNotFoundException
	{
	String host;
	int port;
	RMIClientSocketFactory csf = null;

	byte format = in.readByte();
	switch (format) {
	case FORMAT_HOST_PORT:
	host = in.readUTF();
	port = in.readInt();
	break;

	case FORMAT_HOST_PORT_FACTORY:
	host = in.readUTF();
	port = in.readInt();
	csf = (RMIClientSocketFactory) in.readObject();
	if (csf != null && Proxy.isProxyClass(csf.getClass())) {
	throw new IOException("Invalid SocketFactory");
	}
	break;

	default:
	throw new IOException("invalid endpoint format");
	}
	return new TCPEndpoint(host, port, csf, null);
	}

	/**
	* Write endpoint to output stream in older format used by
	* UnicastRef for JDK1.1 compatibility.
	*/
	public void writeHostPortFormat(DataOutput out) throws IOException {
	if (csf != null) {
	throw new InternalError("TCPEndpoint.writeHostPortFormat: " +
	"called for endpoint with non-null socket factory");
	}
	out.writeUTF(host);
	out.writeInt(port);
	}

	/**
	* Create a new endpoint from input stream data.
	* @param in the input stream
	*/
	public static TCPEndpoint readHostPortFormat(DataInput in)
	throws IOException
	{
	String host = in.readUTF();
	int port = in.readInt();
	return new TCPEndpoint(host, port);
	}

	private static RMISocketFactory chooseFactory() {
	RMISocketFactory sf = RMISocketFactory.getSocketFactory();
	if (sf == null) {
	sf = TCPTransport.defaultSocketFactory;
	}
	return sf;
	}

	/**
	* Open and return new client socket connection to endpoint.
	*/
	Socket newSocket() throws RemoteException {
	if (TCPTransport.tcpLog.isLoggable(Log.VERBOSE)) {
	TCPTransport.tcpLog.log(Log.VERBOSE,
	"opening socket to " + this);
	}

	Socket socket;

	try {
	RMIClientSocketFactory clientFactory = csf;
	if (clientFactory == null) {
	clientFactory = chooseFactory();
	}
	socket = clientFactory.createSocket(host, port);

	} catch (java.net.UnknownHostException e) {
	throw new java.rmi.UnknownHostException(
	"Unknown host: " + host, e);
	} catch (java.net.ConnectException e) {
	throw new java.rmi.ConnectException(
	"Connection refused to host: " + host, e);
	} catch (IOException e) {
	// We might have simply run out of file descriptors
	try {
	TCPEndpoint.shedConnectionCaches();
	// REMIND: should we retry createSocket?
	} catch (OutOfMemoryError \| Exception mem) {
	// don't quit if out of memory
	// or shed fails non-catastrophically
	}

	throw new ConnectIOException("Exception creating connection to: " +
	host, e);
	}

	// set socket to disable Nagle's algorithm (always send immediately)
	// TBD: should this be left up to socket factory instead?
	try {
	socket.setTcpNoDelay(true);
	} catch (Exception e) {
	// if we fail to set this, ignore and proceed anyway
	}

	// fix 4187495: explicitly set SO_KEEPALIVE to prevent client hangs
	try {
	socket.setKeepAlive(true);
	} catch (Exception e) {
	// ignore and proceed
	}

	return socket;
	}

	/**
	* Return new server socket to listen for connections on this endpoint.
	*/
	ServerSocket newServerSocket() throws IOException {
	if (TCPTransport.tcpLog.isLoggable(Log.VERBOSE)) {
	TCPTransport.tcpLog.log(Log.VERBOSE,
	"creating server socket on " + this);
	}

	RMIServerSocketFactory serverFactory = ssf;
	if (serverFactory == null) {
	serverFactory = chooseFactory();
	}
	ServerSocket server = serverFactory.createServerSocket(listenPort);

	// if we listened on an anonymous port, set the default port
	// (for this socket factory)
	if (listenPort == 0)
	setDefaultPort(server.getLocalPort(), csf, ssf);

	return server;
	}

	/**
	* The class FQDN encapsulates a routine that makes a best effort
	* attempt to retrieve the fully qualified domain name of the local
	* host.
	*
	* @author Laird Dornin
	*/
	private static class FQDN implements Runnable {

	/**
	* strings in which we can store discovered fqdn
	*/
	private String reverseLookup;

	private String hostAddress;

	private FQDN(String hostAddress) {
	this.hostAddress = hostAddress;
	}

	/**
	* Do our best to obtain a fully qualified hostname for the local
	* host. Perform the following steps to get a localhostname:
	*
	* 1. InetAddress.getLocalHost().getHostName() - if contains
	* '.' use as FQDN
	* 2. if no '.' query name service for FQDN in a thread
	* Note: We query the name service for an FQDN by creating
	* an InetAddress via a stringified copy of the local ip
	* address; this creates an InetAddress with a null hostname.
	* Asking for the hostname of this InetAddress causes a name
	* service lookup.
	*
	* 3. if name service takes too long to return, use ip address
	* 4. if name service returns but response contains no '.'
	* default to ipaddress.
	*/
	static String attemptFQDN(InetAddress localAddr)
	throws java.net.UnknownHostException
	{

	String hostName = localAddr.getHostName();

	if (hostName.indexOf('.') < 0 ) {

	String hostAddress = localAddr.getHostAddress();
	FQDN f = new FQDN(hostAddress);

	int nameServiceTimeOut =
	TCPEndpoint.getInt("sun.rmi.transport.tcp.localHostNameTimeOut",
	10000);

	try {
	synchronized(f) {
	f.getFQDN();

	/* wait to obtain an FQDN */
	f.wait(nameServiceTimeOut);
	}
	} catch (InterruptedException e) {
	/* propagate the exception to the caller */
	Thread.currentThread().interrupt();
	}
	hostName = f.getHost();

	if ((hostName == null) \|\| (hostName.equals(""))
	\|\| (hostName.indexOf('.') < 0 )) {

	hostName = hostAddress;
	}
	}
	return hostName;
	}

	/**
	* Method that that will start a thread to wait to retrieve a
	* fully qualified domain name from a name service. The spawned
	* thread may never return but we have marked it as a daemon so the vm
	* will terminate appropriately.
	*/
	private void getFQDN() {

	/* FQDN finder will run in RMI threadgroup. */
	Thread t = AccessController.doPrivileged(
	new NewThreadAction(FQDN.this, "FQDN Finder", true));
	t.start();
	}

	private synchronized String getHost() {
	return reverseLookup;
	}

	/**
	* thread to query a name service for the fqdn of this host.
	*/
	public void run() {

	String name = null;

	try {
	name = InetAddress.getByName(hostAddress).getHostName();
	} catch (java.net.UnknownHostException e) {
	} finally {
	synchronized(this) {
	reverseLookup = name;
	this.notify();
	}
	}
	}
	}
	}

Back to index...