/*

 * Copyright 2002-2007 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.security.ssl;

/**

 * Type safe enum for an SSL/TLS protocol version. Instances are obtained

 * using the static factory methods or by referencing the static members

 * in this class. Member variables are final and can be accessed without

 * accessor methods.

 *

 * There is only ever one instance per supported protocol version, this

 * means == can be used for comparision instead of equals() if desired.

 *

 * Checks for a particular version number should generally take this form:

 *

 * if (protocolVersion.v >= ProtocolVersion.TLS10) {

 *   // TLS 1.0 code goes here

 * } else {

 *   // SSL 3.0 code here

 * }

 *

 * @author  Andreas Sterbenz

 * @since   1.4.1

 */

final class ProtocolVersion {

    // dummy protocol version value for invalid SSLSession

    final static ProtocolVersion NONE = new ProtocolVersion(-1, "NONE");

    // If enabled, send/ accept SSLv2 hello messages

    final static ProtocolVersion SSL20Hello = new ProtocolVersion(0x0002,

                                                                "SSLv2Hello");

    // SSL 3.0

    final static ProtocolVersion SSL30 = new ProtocolVersion(0x0300, "SSLv3");

    // TLS 1.0

    final static ProtocolVersion TLS10 = new ProtocolVersion(0x0301, "TLSv1");

    // TLS 1.1

    // not supported yet, but added for better readability of the debug trace

    final static ProtocolVersion TLS11 = new ProtocolVersion(0x0302, "TLSv1.1");

    private static final boolean FIPS = SunJSSE.isFIPS();

    // minimum version we implement (SSL 3.0)

    final static ProtocolVersion MIN = FIPS ? TLS10 : SSL30;

    // maximum version we implement (TLS 1.0)

    final static ProtocolVersion MAX = TLS10;

    // ProtocolVersion to use by default (TLS 1.0)

    final static ProtocolVersion DEFAULT = TLS10;

    // Default version for hello messages (SSLv2Hello)

    final static ProtocolVersion DEFAULT_HELLO = FIPS ? TLS10 : SSL20Hello;

    // version in 16 bit MSB format as it appears in records and

    // messages, i.e. 0x0301 for TLS 1.0

    final int v;

    // major and minor version

    final byte major, minor;

    // name used in JSSE (e.g. TLSv1 for TLS 1.0)

    final String name;

    // private

    private ProtocolVersion(int v, String name) {

        this.v = v;

        this.name = name;

        major = (byte)(v >>> 8);

        minor = (byte)(v & 0xff);

    }

    // private

    private static ProtocolVersion valueOf(int v) {

        if (v == SSL30.v) {

            return SSL30;

        } else if (v == TLS10.v) {

            return TLS10;

        } else if (v == TLS11.v) {

            return TLS11;

        } else if (v == SSL20Hello.v) {

            return SSL20Hello;

        } else {

            int major = (v >>> 8) & 0xff;

            int minor = v & 0xff;

            return new ProtocolVersion(v, "Unknown-" + major + "." + minor);

        }

    }

    /**

     * Return a ProtocolVersion with the specified major and minor version

     * numbers. Never throws exceptions.

     */

    static ProtocolVersion valueOf(int major, int minor) {

        major &= 0xff;

        minor &= 0xff;

        int v = (major << 8) | minor;

        return valueOf(v);

    }

    /**

     * Return a ProtocolVersion for the given name.

     *

     * @exception IllegalArgumentException if name is null or does not

     * identify a supported protocol

     */

    static ProtocolVersion valueOf(String name) {

        if (name == null) {

            throw new IllegalArgumentException("Protocol cannot be null");

        }

        if (FIPS) {

            if (name.equals(TLS10.name)) {

                return TLS10;

            } else {

                throw new IllegalArgumentException

                    ("Only TLS 1.0 allowed in FIPS mode");

            }

        }

        if (name.equals(SSL30.name)) {

            return SSL30;

        } else if (name.equals(TLS10.name)) {

            return TLS10;

        } else if (name.equals(SSL20Hello.name)) {

            return SSL20Hello;

        } else {

            throw new IllegalArgumentException(name);

        }

    }

    public String toString() {

        return name;

    }

}