/*

 * 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

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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) {

                shc.conContext.fatal(Alert.UNEXPECTED_MESSAGE, ioe);

                return;     // fatal() always throws, make the compiler happy.

            }

            // 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) {

                shc.conContext.fatal(Alert.HANDSHAKE_FAILURE,

                        "pre_shared_key key extension is offered " +

                        "without a psk_key_exchange_modes extension");

            }

        }

    }

}