1 /*

     2  * Copyright (c) 2002, 2015, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

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

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package sun.security.ssl;

    27 

    28 import java.util.*;

    29 

    30 /**

    31  * A list of ProtocolVersions. Also maintains the list of supported protocols.

    32  * Instances of this class are immutable. Some member variables are final

    33  * and can be accessed directly without method accessors.

    34  *

    35  * @author  Andreas Sterbenz

    36  * @since   1.4.1

    37  */

    38 final class ProtocolList {

    39 

    40     // the sorted protocol version list

    41     private final ArrayList<ProtocolVersion> protocols;

    42 

    43     private String[] protocolNames;

    44 

    45     // the minimum and maximum ProtocolVersions in this list

    46     final ProtocolVersion min, max;

    47 

    48     // the format for the hello version to use

    49     final ProtocolVersion helloVersion;

    50 

    51     ProtocolList(String[] names) {

    52         this(convert(names));

    53     }

    54 

    55     ProtocolList(ArrayList<ProtocolVersion> versions) {

    56         this.protocols = versions;

    57 

    58         if ((protocols.size() == 1) &&

    59                 protocols.contains(ProtocolVersion.SSL20Hello)) {

    60             throw new IllegalArgumentException("SSLv2Hello cannot be " +

    61                 "enabled unless at least one other supported version " +

    62                 "is also enabled.");

    63         }

    64 

    65         if (protocols.size() != 0) {

    66             Collections.sort(protocols);

    67             min = protocols.get(0);

    68             max = protocols.get(protocols.size() - 1);

    69             helloVersion = protocols.get(0);

    70         } else {

    71             min = ProtocolVersion.NONE;

    72             max = ProtocolVersion.NONE;

    73             helloVersion = ProtocolVersion.NONE;

    74         }

    75     }

    76 

    77     private static ArrayList<ProtocolVersion> convert(String[] names) {

    78         if (names == null) {

    79             throw new IllegalArgumentException("Protocols may not be null");

    80         }

    81 

    82         ArrayList<ProtocolVersion> versions = new ArrayList<>(names.length);

    83         for (int i = 0; i < names.length; i++ ) {

    84             ProtocolVersion version = ProtocolVersion.valueOf(names[i]);

    85             if (versions.contains(version) == false) {

    86                 versions.add(version);

    87             }

    88         }

    89 

    90         return versions;

    91     }

    92 

    93     /**

    94      * Return whether this list contains the specified protocol version.

    95      * SSLv2Hello is not a real protocol version we support, we always

    96      * return false for it.

    97      */

    98     boolean contains(ProtocolVersion protocolVersion) {

    99         if (protocolVersion == ProtocolVersion.SSL20Hello) {

   100             return false;

   101         }

   102         return protocols.contains(protocolVersion);

   103     }

   104 

   105     /**

   106      * Return a reference to the internal Collection of CipherSuites.

   107      * The Collection MUST NOT be modified.

   108      */

   109     Collection<ProtocolVersion> collection() {

   110         return protocols;

   111     }

   112 

   113     /**

   114      * Select a protocol version from the list.

   115      *

   116      * Return the lower of the protocol version of that suggested by

   117      * the <code>protocolVersion</code> and the highest version of this

   118      * protocol list, or null if no protocol version is available.

   119      *

   120      * The method is used by TLS server to negotiated the protocol

   121      * version between client suggested protocol version in the

   122      * client hello and protocol versions supported by the server.

   123      */

   124     ProtocolVersion selectProtocolVersion(ProtocolVersion protocolVersion) {

   125         ProtocolVersion selectedVersion = null;

   126         for (ProtocolVersion pv : protocols) {

   127             if (pv.compareTo(protocolVersion) > 0) {

   128                 break;      // Safe to break here as this.protocols is sorted,

   129                             // and DTLS and SSL/TLS protocols are not mixed.

   130             }

   131             selectedVersion = pv;

   132         }

   133 

   134         return selectedVersion;

   135     }

   136 

   137     /**

   138      * Return an array with the names of the ProtocolVersions in this list.

   139      */

   140     synchronized String[] toStringArray() {

   141         if (protocolNames == null) {

   142             protocolNames = new String[protocols.size()];

   143             int i = 0;

   144             for (ProtocolVersion version : protocols) {

   145                 protocolNames[i++] = version.name;

   146             }

   147         }

   148         return protocolNames.clone();

   149     }

   150 

   151     @Override

   152     public String toString() {

   153         return protocols.toString();

   154     }

   155 }