/*
 * Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package sun.security.ssl;

import java.io.IOException;
import java.io.PrintStream;
import java.util.*;
import javax.net.ssl.*;

This file contains all the classes relevant to TLS Extensions for the
ClientHello and ServerHello messages. The extension mechanism and
several extensions are defined in RFC 3546. Additional extensions are
defined in the ECC RFC 4492.
Currently, only the two ECC extensions are fully supported.
The classes contained in this file are:
 . HelloExtensions: a List of extensions as used in the client hello
     and server hello messages.
 . ExtensionType: an enum style class for the extension type
 . HelloExtension: abstract base class for all extensions. All subclasses
     must be immutable.
 . UnknownExtension: used to represent all parsed extensions that we do not
     explicitly support.
 . ServerNameExtension: the server_name extension.
 . SignatureAlgorithmsExtension: the signature_algorithms extension.
 . EllipticCurvesExtension: the ECC supported curves extension.
 . EllipticPointFormatsExtension: the ECC supported point formats
     (compressed/uncompressed) extension.
Author:
 Andreas Sterbenz
Since:
  1.6/**
 * This file contains all the classes relevant to TLS Extensions for the
 * ClientHello and ServerHello messages. The extension mechanism and
 * several extensions are defined in RFC 3546. Additional extensions are
 * defined in the ECC RFC 4492.
 *
 * Currently, only the two ECC extensions are fully supported.
 *
 * The classes contained in this file are:
 *  . HelloExtensions: a List of extensions as used in the client hello
 *      and server hello messages.
 *  . ExtensionType: an enum style class for the extension type
 *  . HelloExtension: abstract base class for all extensions. All subclasses
 *      must be immutable.
 *
 *  . UnknownExtension: used to represent all parsed extensions that we do not
 *      explicitly support.
 *  . ServerNameExtension: the server_name extension.
 *  . SignatureAlgorithmsExtension: the signature_algorithms extension.
 *  . EllipticCurvesExtension: the ECC supported curves extension.
 *  . EllipticPointFormatsExtension: the ECC supported point formats
 *      (compressed/uncompressed) extension.
 *
 * @since   1.6
 * @author  Andreas Sterbenz
 */
final class HelloExtensions {

    private List<HelloExtension> extensions;
    private int encodedLength;

    HelloExtensions() {
        extensions = Collections.emptyList();
    }

    HelloExtensions(HandshakeInStream s) throws IOException {
        int len = s.getInt16();
        extensions = new ArrayList<HelloExtension>();
        encodedLength = len + 2;
        while (len > 0) {
            int type = s.getInt16();
            int extlen = s.getInt16();
            ExtensionType extType = ExtensionType.get(type);
            HelloExtension extension;
            if (extType == ExtensionType.EXT_SERVER_NAME) {
                extension = new ServerNameExtension(s, extlen);
            } else if (extType == ExtensionType.EXT_SIGNATURE_ALGORITHMS) {
                extension = new SignatureAlgorithmsExtension(s, extlen);
            } else if (extType == ExtensionType.EXT_ELLIPTIC_CURVES) {
                extension = new EllipticCurvesExtension(s, extlen);
            } else if (extType == ExtensionType.EXT_EC_POINT_FORMATS) {
                extension = new EllipticPointFormatsExtension(s, extlen);
            } else if (extType == ExtensionType.EXT_RENEGOTIATION_INFO) {
                extension = new RenegotiationInfoExtension(s, extlen);
            // BEGIN GRIZZLY NPN
            } else if (extType == ExtensionType.EXT_NEXT_PROTOCOL_NEGOTIATION) {
                extension = NextProtocolNegotiationExtension.builder().handshakeIn(s, extlen).build();
            } else if (extType == ExtensionType.EXT_APPLICATION_LEVEL_PROTOCOL_NEGOTIATION) {
                extension = AlpnExtension.builder().handshakeIn(s, extlen).build();
            // END GRIZZLY NPN
            } else if (extType == ExtensionType.EXT_EXTENDED_MASTER_SECRET) {
                extension = new ExtendedMasterSecretExtension(s, extlen);
            } else {
                extension = new UnknownExtension(s, extlen, extType);
            }
            extensions.add(extension);
            len -= extlen + 4;
        }
        if (len != 0) {
            throw new SSLProtocolException(
                        "Error parsing extensions: extra data");
        }
    }

    // Return the List of extensions. Must not be modified by the caller.
    List<HelloExtension> list() {
        return extensions;
    }

    void add(HelloExtension ext) {
        if (extensions.isEmpty()) {
            extensions = new ArrayList<HelloExtension>();
        }
        extensions.add(ext);
        encodedLength = -1;
    }

    HelloExtension get(ExtensionType type) {
        for (HelloExtension ext : extensions) {
            if (ext.type == type) {
                return ext;
            }
        }
        return null;
    }

    int length() {
        if (encodedLength >= 0) {
            return encodedLength;
        }
        if (extensions.isEmpty()) {
            encodedLength = 0;
        } else {
            encodedLength = 2;
            for (HelloExtension ext : extensions) {
                encodedLength += ext.length();
            }
        }
        return encodedLength;
    }

    void send(HandshakeOutStream s) throws IOException {
        int length = length();
        if (length == 0) {
            return;
        }
        s.putInt16(length - 2);
        for (HelloExtension ext : extensions) {
            ext.send(s);
        }
    }

    void print(PrintStream s) throws IOException {
        for (HelloExtension ext : extensions) {
            s.println(ext.toString());
        }
    }
}