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	/*
	* Copyright (c) 2018, 2020, 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 sun.security.ssl.SSLHandshake.HandshakeMessage;
	import sun.security.util.HexDumpEncoder;

	/**
	* SSL/(D)TLS extensions in a handshake message.
	*/
	final class SSLExtensions {
	private final HandshakeMessage handshakeMessage;
	private final Map<SSLExtension, byte[]> extMap = new LinkedHashMap<>();
	private int encodedLength;

	// Extension map for debug logging
	private final Map<Integer, byte[]> logMap =
	SSLLogger.isOn ? new LinkedHashMap<>() : null;

	SSLExtensions(HandshakeMessage handshakeMessage) {
	this.handshakeMessage = handshakeMessage;
	this.encodedLength = 2; // 2: the length of the extensions.
	}

	SSLExtensions(HandshakeMessage hm,
	ByteBuffer m, SSLExtension[] extensions) throws IOException {
	this.handshakeMessage = hm;

	if (m.remaining() < 2) {
	throw hm.handshakeContext.conContext.fatal(
	Alert.DECODE_ERROR,
	"Incorrect extensions: no length field");
	}

	int len = Record.getInt16(m);
	if (len > m.remaining()) {
	throw hm.handshakeContext.conContext.fatal(
	Alert.DECODE_ERROR,
	"Insufficient extensions data");
	}

	encodedLength = len + 2; // 2: the length of the extensions.
	while (len > 0) {
	int extId = Record.getInt16(m);
	int extLen = Record.getInt16(m);
	if (extLen > m.remaining()) {
	throw hm.handshakeContext.conContext.fatal(
	Alert.DECODE_ERROR,
	"Error parsing extension (" + extId +
	"): no sufficient data");
	}

	boolean isSupported = true;
	SSLHandshake handshakeType = hm.handshakeType();
	if (SSLExtension.isConsumable(extId) &&
	SSLExtension.valueOf(handshakeType, extId) == null) {
	if (extId == SSLExtension.CH_SUPPORTED_GROUPS.id &&
	handshakeType == SSLHandshake.SERVER_HELLO) {
	// Note: It does not comply to the specification. However,
	// there are servers that send the supported_groups
	// extension in ServerHello handshake message.
	//
	// TLS 1.3 should not send this extension. We may want to
	// limit the workaround for TLS 1.2 and prior version only.
	// However, the implementation of the limit is complicated
	// and inefficient, and may not worthy the maintenance.
	isSupported = false;
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning(
	"Received buggy supported_groups extension " +
	"in the ServerHello handshake message");
	}
	} else if (handshakeType == SSLHandshake.SERVER_HELLO) {
	throw hm.handshakeContext.conContext.fatal(
	Alert.UNSUPPORTED_EXTENSION, "extension (" +
	extId + ") should not be presented in " +
	handshakeType.name);
	} else {
	isSupported = false;
	// debug log to ignore unknown extension for handshakeType
	}
	}

	if (isSupported) {
	isSupported = false;
	for (SSLExtension extension : extensions) {
	if ((extension.id != extId) \|\|
	(extension.onLoadConsumer == null)) {
	continue;
	}

	if (extension.handshakeType != handshakeType) {
	throw hm.handshakeContext.conContext.fatal(
	Alert.UNSUPPORTED_EXTENSION,
	"extension (" + extId + ") should not be " +
	"presented in " + handshakeType.name);
	}

	byte[] extData = new byte[extLen];
	m.get(extData);
	extMap.put(extension, extData);
	if (logMap != null) {
	logMap.put(extId, extData);
	}

	isSupported = true;
	break;
	}
	}

	if (!isSupported) {
	if (logMap != null) {
	// cache the extension for debug logging
	byte[] extData = new byte[extLen];
	m.get(extData);
	logMap.put(extId, extData);

	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"Ignore unknown or unsupported extension",
	toString(extId, extData));
	}
	} else {
	// ignore the extension
	int pos = m.position() + extLen;
	m.position(pos);
	}
	}

	len -= extLen + 4;
	}
	}

	byte[] get(SSLExtension ext) {
	return extMap.get(ext);
	}

	/**
	* Consume the specified extensions.
	*/
	void consumeOnLoad(HandshakeContext context,
	SSLExtension[] extensions) throws IOException {
	for (SSLExtension extension : extensions) {
	if (context.negotiatedProtocol != null &&
	!extension.isAvailable(context.negotiatedProtocol)) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"Ignore unsupported extension: " + extension.name);
	}
	continue;
	}

	if (!extMap.containsKey(extension)) {
	if (extension.onLoadAbsence != null) {
	extension.absentOnLoad(context, handshakeMessage);
	} else if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"Ignore unavailable extension: " + extension.name);
	}
	continue;
	}


	if (extension.onLoadConsumer == null) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning(
	"Ignore unsupported extension: " + extension.name);
	}
	continue;
	}

	ByteBuffer m = ByteBuffer.wrap(extMap.get(extension));
	extension.consumeOnLoad(context, handshakeMessage, m);

	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine("Consumed extension: " + extension.name);
	}
	}
	}

	/**
	* Consider impact of the specified extensions.
	*/
	void consumeOnTrade(HandshakeContext context,
	SSLExtension[] extensions) throws IOException {
	for (SSLExtension extension : extensions) {
	if (!extMap.containsKey(extension)) {
	if (extension.onTradeAbsence != null) {
	extension.absentOnTrade(context, handshakeMessage);
	} else if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"Ignore unavailable extension: " + extension.name);
	}
	continue;
	}

	if (extension.onTradeConsumer == null) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning(
	"Ignore impact of unsupported extension: " +
	extension.name);
	}
	continue;
	}

	extension.consumeOnTrade(context, handshakeMessage);
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine("Populated with extension: " + extension.name);
	}
	}
	}

	/**
	* Produce extension values for the specified extensions.
	*/
	void produce(HandshakeContext context,
	SSLExtension[] extensions) throws IOException {
	for (SSLExtension extension : extensions) {
	if (extMap.containsKey(extension)) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.fine(
	"Ignore, duplicated extension: " +
	extension.name);
	}
	continue;
	}

	if (extension.networkProducer == null) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning(
	"Ignore, no extension producer defined: " +
	extension.name);
	}
	continue;
	}

	byte[] encoded = extension.produce(context, handshakeMessage);
	if (encoded != null) {
	extMap.put(extension, encoded);
	encodedLength += encoded.length + 4; // extension_type (2)
	// extension_data length(2)
	} else if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	// The extension is not available in the context.
	SSLLogger.fine(
	"Ignore, context unavailable extension: " +
	extension.name);
	}
	}
	}

	/**
	* Produce extension values for the specified extensions, replacing if
	* there is an existing extension value for a specified extension.
	*/
	void reproduce(HandshakeContext context,
	SSLExtension[] extensions) throws IOException {
	for (SSLExtension extension : extensions) {
	if (extension.networkProducer == null) {
	if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	SSLLogger.warning(
	"Ignore, no extension producer defined: " +
	extension.name);
	}
	continue;
	}

	byte[] encoded = extension.produce(context, handshakeMessage);
	if (encoded != null) {
	if (extMap.containsKey(extension)) {
	byte[] old = extMap.replace(extension, encoded);
	if (old != null) {
	encodedLength -= old.length + 4;
	}
	encodedLength += encoded.length + 4;
	} else {
	extMap.put(extension, encoded);
	encodedLength += encoded.length + 4;
	// extension_type (2)
	// extension_data length(2)
	}
	} else if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {
	// The extension is not available in the context.
	SSLLogger.fine(
	"Ignore, context unavailable extension: " +
	extension.name);
	}
	}
	}

	// Note that TLS 1.3 may use empty extensions. Please consider it while
	// using this method.
	int length() {
	if (extMap.isEmpty()) {
	return 0;
	} else {
	return encodedLength;
	}
	}

	// Note that TLS 1.3 may use empty extensions. Please consider it while
	// using this method.
	void send(HandshakeOutStream hos) throws IOException {
	int extsLen = length();
	if (extsLen == 0) {
	return;
	}
	hos.putInt16(extsLen - 2);
	// extensions must be sent in the order they appear in the enum
	for (SSLExtension ext : SSLExtension.values()) {
	byte[] extData = extMap.get(ext);
	if (extData != null) {
	hos.putInt16(ext.id);
	hos.putBytes16(extData);
	}
	}
	}

	@Override
	public String toString() {
	if (extMap.isEmpty() && (logMap == null \|\| logMap.isEmpty())) {
	return "<no extension>";
	} else {
	StringBuilder builder = new StringBuilder(512);
	if (logMap != null && !logMap.isEmpty()) {
	for (Map.Entry<Integer, byte[]> en : logMap.entrySet()) {
	SSLExtension ext = SSLExtension.valueOf(
	handshakeMessage.handshakeType(), en.getKey());
	if (builder.length() != 0) {
	builder.append(",\n");
	}
	if (ext != null) {
	builder.append(
	ext.toString(handshakeMessage.handshakeContext,
	ByteBuffer.wrap(en.getValue())));
	} else {
	builder.append(toString(en.getKey(), en.getValue()));
	}
	}

	return builder.toString();
	} else {
	for (Map.Entry<SSLExtension, byte[]> en : extMap.entrySet()) {
	if (builder.length() != 0) {
	builder.append(",\n");
	}
	builder.append(
	en.getKey().toString(handshakeMessage.handshakeContext,
	ByteBuffer.wrap(en.getValue())));
	}

	return builder.toString();
	}
	}
	}

	private static String toString(int extId, byte[] extData) {
	String extName = SSLExtension.nameOf(extId);
	MessageFormat messageFormat = new MessageFormat(
	"\"{0} ({1})\": '{'\n" +
	"{2}\n" +
	"'}'",
	Locale.ENGLISH);

	HexDumpEncoder hexEncoder = new HexDumpEncoder();
	String encoded = hexEncoder.encodeBuffer(extData);

	Object[] messageFields = {
	extName,
	extId,
	Utilities.indent(encoded)
	};

	return messageFormat.format(messageFields);
	}
	}

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