/*

 * Copyright (c) 2015, 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.util.Objects;

/*

 * RFC6066 defines the TLS extension,"status_request" (type 0x5),

 * which allows the client to request that the server perform OCSP

 * on the client's behalf.

 * The "extension data" field of this extension contains a

 * "CertificateStatusRequest" structure:

 *

 *      struct {

 *          CertificateStatusType status_type;

 *          select (status_type) {

 *              case ocsp: OCSPStatusRequest;

 *          } request;

 *      } CertificateStatusRequest;

 *

 *      enum { ocsp(1), (255) } CertificateStatusType;

 *

 *      struct {

 *          ResponderID responder_id_list<0..2^16-1>;

 *          Extensions  request_extensions;

 *      } OCSPStatusRequest;

 *

 *      opaque ResponderID<1..2^16-1>;

 *      opaque Extensions<0..2^16-1>;

 */

final class CertStatusReqExtension extends HelloExtension {

    private final StatusRequestType statReqType;

    private final StatusRequest request;

    /**

     * Construct the default status request extension object.  The default

     * object results in a status_request extension where the extension

     * data segment is zero-length.  This is used primarily in ServerHello

     * messages where the server asserts it can do RFC 6066 status stapling.

     */

    CertStatusReqExtension() {

        super(ExtensionType.EXT_STATUS_REQUEST);

        statReqType = null;

        request = null;

    }

    /**

     * Construct the status request extension object given a request type

     *      and {@code StatusRequest} object.

     *

     * @param reqType a {@code StatusRequestExtType object correspoding

     *      to the underlying {@code StatusRequest} object.  A value of

     *      {@code null} is not allowed.

     * @param statReq the {@code StatusRequest} object used to provide the

     *      encoding for the TLS extension.  A value of {@code null} is not

     *      allowed.

     *

     * @throws IllegalArgumentException if the provided {@code StatusRequest}

     *      does not match the type.

     * @throws NullPointerException if either the {@code reqType} or

     *      {@code statReq} arguments are {@code null}.

     */

    CertStatusReqExtension(StatusRequestType reqType, StatusRequest statReq) {

        super(ExtensionType.EXT_STATUS_REQUEST);

        statReqType = Objects.requireNonNull(reqType,

                "Unallowed null value for status_type");

        request = Objects.requireNonNull(statReq,

                "Unallowed null value for request");

        // There is currently only one known status type (OCSP)

        // We can add more clauses to cover other types in the future

        if (statReqType == StatusRequestType.OCSP) {

            if (!(statReq instanceof OCSPStatusRequest)) {

                throw new IllegalArgumentException("StatusRequest not " +

                        "of type OCSPStatusRequest");

            }

        }

    }

    /**

     * Construct the {@code CertStatusReqExtension} object from data read from

     *      a {@code HandshakeInputStream}

     *

     * @param s the {@code HandshakeInputStream} providing the encoded data

     * @param len the length of the extension data

     *

     * @throws IOException if any decoding errors happen during object

     *      construction.

     */

    CertStatusReqExtension(HandshakeInStream s, int len) throws IOException {

        super(ExtensionType.EXT_STATUS_REQUEST);

        if (len > 0) {

            // Obtain the status type (first byte)

            statReqType = StatusRequestType.get(s.getInt8());

            if (statReqType == StatusRequestType.OCSP) {

                request = new OCSPStatusRequest(s);

            } else {

                // This is a status_type we don't understand.  Create

                // an UnknownStatusRequest in order to preserve the data

                request = new UnknownStatusRequest(s, len - 1);

            }

        } else {

            // Treat this as a zero-length extension (i.e. from a ServerHello

            statReqType = null;

            request = null;

        }

    }

    /**

     * Return the length of the encoded extension, including extension type,

     *      extension length and status_type fields.

     *

     * @return the length in bytes, including the extension type and

     *      length fields.

     */

    @Override

    int length() {

        return (statReqType != null ? 5 + request.length() : 4);

    }

    /**

     * Send the encoded TLS extension through a {@code HandshakeOutputStream}

     *

     * @param s the {@code HandshakeOutputStream} used to send the encoded data

     *

     * @throws IOException tf any errors occur during the encoding process

     */

    @Override

    void send(HandshakeOutStream s) throws IOException {

        s.putInt16(type.id);

        s.putInt16(this.length() - 4);

        if (statReqType != null) {

            s.putInt8(statReqType.id);

            request.send(s);

        }

    }

    /**

     * Create a string representation of this {@code CertStatusReqExtension}

     *

     * @return the string representation of this {@code CertStatusReqExtension}

     */

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder("Extension ").append(type);

        if (statReqType != null) {

            sb.append(": ").append(statReqType).append(", ").append(request);

        }

        return sb.toString();

    }

    /**

     * Return the type field for this {@code CertStatusReqExtension}

     *

     * @return the {@code StatusRequestType} for this extension.  {@code null}

     *      will be returned if the default constructor is used to create

     *      a zero length status_request extension (found in ServerHello

     *      messages)

     */

    StatusRequestType getType() {

        return statReqType;

    }

    /**

     * Get the underlying {@code StatusRequest} for this

     *      {@code CertStatusReqExtension}

     *

     * @return the {@code StatusRequest} or {@code null} if the default

     * constructor was used to create this extension.

     */

    StatusRequest getRequest() {

        return request;

    }

}