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	/*
	* Copyright (c) 2018, 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.security.ssl;

	import java.io.IOException;
	import java.nio.ByteBuffer;
	import java.text.MessageFormat;
	import java.util.*;
	import javax.net.ssl.SSLProtocolException;
	import sun.security.ssl.SSLExtension.ExtensionConsumer;

	import sun.security.ssl.SSLExtension.SSLExtensionSpec;
	import sun.security.ssl.SSLHandshake.HandshakeMessage;

	/**
	* Pack of the "psk_key_exchange_modes" extensions.
	*/
	final class PskKeyExchangeModesExtension {
	static final HandshakeProducer chNetworkProducer =
	new PskKeyExchangeModesProducer();
	static final ExtensionConsumer chOnLoadConsumer =
	new PskKeyExchangeModesConsumer();
	static final HandshakeAbsence chOnLoadAbsence =
	new PskKeyExchangeModesOnLoadAbsence();
	static final HandshakeAbsence chOnTradeAbsence =
	new PskKeyExchangeModesOnTradeAbsence();

	static final SSLStringizer pkemStringizer =
	new PskKeyExchangeModesStringizer();

	enum PskKeyExchangeMode {
	PSK_KE ((byte)0, "psk_ke"),
	PSK_DHE_KE ((byte)1, "psk_dhe_ke");

	final byte id;
	final String name;

	PskKeyExchangeMode(byte id, String name) {
	this.id = id;
	this.name = name;
	}

	static PskKeyExchangeMode valueOf(byte id) {
	for(PskKeyExchangeMode pkem : values()) {
	if (pkem.id == id) {
	return pkem;
	}
	}

	return null;
	}

	static String nameOf(byte id) {
	for (PskKeyExchangeMode pkem : PskKeyExchangeMode.values()) {
	if (pkem.id == id) {
	return pkem.name;
	}
	}

	return "<UNKNOWN PskKeyExchangeMode TYPE: " + (id & 0x0FF) + ">";
	}
	}

	static final
	class PskKeyExchangeModesSpec implements SSLExtensionSpec {
	private static final PskKeyExchangeModesSpec DEFAULT =
	new PskKeyExchangeModesSpec(new byte[] {
	PskKeyExchangeMode.PSK_DHE_KE.id});

	final byte[] modes;

	PskKeyExchangeModesSpec(byte[] modes) {
	this.modes = modes;
	}

	PskKeyExchangeModesSpec(ByteBuffer m) throws IOException {
	if (m.remaining() < 2) {
	throw new SSLProtocolException(
	"Invalid psk_key_exchange_modes extension: " +
	"insufficient data");
	}

	this.modes = Record.getBytes8(m);
	}

	boolean contains(PskKeyExchangeMode mode) {
	if (modes != null) {
	for (byte m : modes) {
	if (mode.id == m) {
	return true;
	}
	}
	}

	return false;
	}

	@Override
	public String toString() {
	MessageFormat messageFormat = new MessageFormat(
	"\"ke_modes\": '['{0}']'", Locale.ENGLISH);
	if (modes == null \|\| modes.length == 0) {
	Object[] messageFields = {
	"<no PSK key exchange modes specified>"
	};
	return messageFormat.format(messageFields);
	} else {
	StringBuilder builder = new StringBuilder(64);
	boolean isFirst = true;
	for (byte mode : modes) {
	if (isFirst) {
	isFirst = false;
	} else {
	builder.append(", ");
	}

	builder.append(PskKeyExchangeMode.nameOf(mode));
	}

	Object[] messageFields = {
	builder.toString()
	};

	return messageFormat.format(messageFields);
	}
	}
	}

	private static final
	class PskKeyExchangeModesStringizer implements SSLStringizer {
	@Override
	public String toString(ByteBuffer buffer) {
	try {
	return (new PskKeyExchangeModesSpec(buffer)).toString();
	} catch (IOException ioe) {
	// For debug logging only, so please swallow exceptions.
	return ioe.getMessage();
	}
	}
	}

	/**
	* Network data consumer of a "psk_key_exchange_modes" extension in
	* the ClientHello handshake message.
	*/
	private static final
	class PskKeyExchangeModesConsumer implements ExtensionConsumer {
	// Prevent instantiation of this class.
	private PskKeyExchangeModesConsumer() {
	// blank
	}

	@Override
	public void consume(ConnectionContext context,
	HandshakeMessage message, ByteBuffer buffer) throws IOException {

	// The consuming happens in server side only.
	ServerHandshakeContext shc = (ServerHandshakeContext)context;

	// Is it a supported and enabled extension?
	if (!shc.sslConfig.isAvailable(
	SSLExtension.PSK_KEY_EXCHANGE_MODES)) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"Ignore unavailable psk_key_exchange_modes extension");
	}

	// No session resumption is allowed.
	if (shc.isResumption && shc.resumingSession != null) {
	shc.isResumption = false;
	shc.resumingSession = null;
	}

	return; // ignore the extension
	}

	// Parse the extension.
	PskKeyExchangeModesSpec spec;
	try {
	spec = new PskKeyExchangeModesSpec(buffer);
	} catch (IOException ioe) {
	throw shc.conContext.fatal(Alert.UNEXPECTED_MESSAGE, ioe);
	}

	// Update the context.
	shc.handshakeExtensions.put(
	SSLExtension.PSK_KEY_EXCHANGE_MODES, spec);

	// Impact on session resumption.
	//
	// Do the requested modes support session resumption?
	if (shc.isResumption) { // resumingSession may not be set
	// Note: psk_dhe_ke is the only supported mode now. If the
	// psk_ke mode is supported in the future, may need an update
	// here.
	if (!spec.contains(PskKeyExchangeMode.PSK_DHE_KE)) {
	shc.isResumption = false;
	shc.resumingSession = null;
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"abort session resumption, " +
	"no supported psk_dhe_ke PSK key exchange mode");
	}
	}
	}
	}
	}

	/**
	* Network data producer of a "psk_key_exchange_modes" extension in the
	* ClientHello handshake message.
	*/
	private static final
	class PskKeyExchangeModesProducer implements HandshakeProducer {

	// Prevent instantiation of this class.
	private PskKeyExchangeModesProducer() {
	// blank
	}

	@Override
	public byte[] produce(ConnectionContext context,
	HandshakeMessage message) throws IOException {
	// The producing happens in client side only.
	ClientHandshakeContext chc = (ClientHandshakeContext)context;

	// Is it a supported and enabled extension?
	if (!chc.sslConfig.isAvailable(
	SSLExtension.PSK_KEY_EXCHANGE_MODES)) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning(
	"Ignore unavailable psk_key_exchange_modes extension");
	}

	return null;
	}

	byte[] extData = new byte[] {0x01, 0x01}; // psk_dhe_ke

	// Update the context.
	chc.handshakeExtensions.put(
	SSLExtension.PSK_KEY_EXCHANGE_MODES,
	PskKeyExchangeModesSpec.DEFAULT);

	return extData;
	}
	}
	/**
	* The absence processing if a "psk_key_exchange_modes" extension is
	* not present in the ClientHello handshake message.
	*/
	private static final
	class PskKeyExchangeModesOnLoadAbsence implements HandshakeAbsence {

	// Prevent instantiation of this class.
	private PskKeyExchangeModesOnLoadAbsence() {
	// blank
	}

	@Override
	public void absent(ConnectionContext context,
	HandshakeMessage message) throws IOException {
	// The consuming happens in server side only.
	ServerHandshakeContext shc = (ServerHandshakeContext)context;

	// No session resumptio is allowed.
	if (shc.isResumption) { // resumingSession may not be set
	shc.isResumption = false;
	shc.resumingSession = null;
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"abort session resumption, " +
	"no supported psk_dhe_ke PSK key exchange mode");
	}
	}
	}
	}

	/**
	* The absence processing if a "signature_algorithms" extension is
	* not present in the ClientHello handshake message.
	*/
	private static final
	class PskKeyExchangeModesOnTradeAbsence implements HandshakeAbsence {

	// Prevent instantiation of this class.
	private PskKeyExchangeModesOnTradeAbsence() {
	// blank
	}

	@Override
	public void absent(ConnectionContext context,
	HandshakeMessage message) throws IOException {
	// The consuming happens in server side only.
	ServerHandshakeContext shc = (ServerHandshakeContext)context;

	// A client MUST provide a "psk_key_exchange_modes" extension if
	// it offers a "pre_shared_key" extension. If clients offer
	// "pre_shared_key" without a "psk_key_exchange_modes" extension,
	// servers MUST abort the handshake.
	SSLExtensionSpec spec =
	shc.handshakeExtensions.get(SSLExtension.CH_PRE_SHARED_KEY);
	if (spec != null) {
	throw shc.conContext.fatal(Alert.HANDSHAKE_FAILURE,
	"pre_shared_key key extension is offered " +
	"without a psk_key_exchange_modes extension");
	}
	}
	}
	}

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