/*

 * Copyright (c) 1997, 2012, 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.io.PrintStream;

import java.math.BigInteger;

import javax.net.ssl.SSLHandshakeException;

/*

 * Message used by clients to send their Diffie-Hellman public

 * keys to servers.

 *

 * @author David Brownell

 */

final class DHClientKeyExchange extends HandshakeMessage {

    @Override

    int messageType() {

        return ht_client_key_exchange;

    }

    /*

     * This value may be empty if it was included in the

     * client's certificate ...

     */

    private byte[] dh_Yc;               // 1 to 2^16 -1 bytes

    BigInteger getClientPublicKey() {

        return dh_Yc == null ? null : new BigInteger(1, dh_Yc);

    }

    /*

     * Either pass the client's public key explicitly (because it's

     * using DHE or DH_anon), or implicitly (the public key was in the

     * certificate).

     */

    DHClientKeyExchange(BigInteger publicKey) {

        dh_Yc = toByteArray(publicKey);

    }

    DHClientKeyExchange() {

        dh_Yc = null;

    }

    /*

     * Get the client's public key either explicitly or implicitly.

     * (It's ugly to have an empty record be sent in the latter case,

     * but that's what the protocol spec requires.)

     */

    DHClientKeyExchange(HandshakeInStream input) throws IOException {

        if (input.available() >= 2) {

            dh_Yc = input.getBytes16();

        } else {

            // currently, we don't support cipher suites that requires

            // implicit public key of client.

            throw new SSLHandshakeException(

                    "Unsupported implicit client DiffieHellman public key");

        }

    }

    @Override

    int messageLength() {

        if (dh_Yc == null) {

            return 0;

        } else {

            return dh_Yc.length + 2;

        }

    }

    @Override

    void send(HandshakeOutStream s) throws IOException {

        if (dh_Yc != null && dh_Yc.length != 0) {

            s.putBytes16(dh_Yc);

        }

    }

    @Override

    void print(PrintStream s) throws IOException {

        s.println("*** ClientKeyExchange, DH");

        if (debug != null && Debug.isOn("verbose")) {

            Debug.println(s, "DH Public key", dh_Yc);

        }

    }

}