/*

 * Copyright (c) 2012, 2016, 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 javax.net.ssl.*;

import java.util.*;

import sun.net.util.IPAddressUtil;

/**

 * A utility class to share the static methods.

 */

final class Utilities {

    /**

     * hex digits

     */

    static final char[] hexDigits = "0123456789ABCDEF".toCharArray();

    /**

     * Puts {@code hostname} into the {@code serverNames} list.

     * <P>

     * If the {@code serverNames} does not look like a legal FQDN, it will

     * not be put into the returned list.

     * <P>

     * Note that the returned list does not allow duplicated name type.

     *

     * @return a list of {@link SNIServerName}

     */

    static List<SNIServerName> addToSNIServerNameList(

            List<SNIServerName> serverNames, String hostname) {

        SNIHostName sniHostName = rawToSNIHostName(hostname);

        if (sniHostName == null) {

            return serverNames;

        }

        int size = serverNames.size();

        List<SNIServerName> sniList = (size != 0) ?

                new ArrayList<SNIServerName>(serverNames) :

                new ArrayList<SNIServerName>(1);

        boolean reset = false;

        for (int i = 0; i < size; i++) {

            SNIServerName serverName = sniList.get(i);

            if (serverName.getType() == StandardConstants.SNI_HOST_NAME) {

                sniList.set(i, sniHostName);

                if (Debug.isOn("ssl")) {

                    System.out.println(Thread.currentThread().getName() +

                        ", the previous server name in SNI (" + serverName +

                        ") was replaced with (" + sniHostName + ")");

                }

                reset = true;

                break;

            }

        }

        if (!reset) {

            sniList.add(sniHostName);

        }

        return Collections.<SNIServerName>unmodifiableList(sniList);

    }

    /**

     * Converts string hostname to {@code SNIHostName}.

     * <P>

     * Note that to check whether a hostname is a valid domain name, we cannot

     * use the hostname resolved from name services.  For virtual hosting,

     * multiple hostnames may be bound to the same IP address, so the hostname

     * resolved from name services is not always reliable.

     *

     * @param  hostname

     *         the raw hostname

     * @return an instance of {@link SNIHostName}, or null if the hostname does

     *         not look like a FQDN

     */

    private static SNIHostName rawToSNIHostName(String hostname) {

        SNIHostName sniHostName = null;

        if (hostname != null && hostname.indexOf('.') > 0 &&

                !hostname.endsWith(".") &&

                !IPAddressUtil.isIPv4LiteralAddress(hostname) &&

                !IPAddressUtil.isIPv6LiteralAddress(hostname)) {

            try {

                sniHostName = new SNIHostName(hostname);

            } catch (IllegalArgumentException iae) {

                // don't bother to handle illegal host_name

                if (Debug.isOn("ssl")) {

                    System.out.println(Thread.currentThread().getName() +

                        ", \"" + hostname + "\" " +

                        "is not a legal HostName for  server name indication");

                }

            }

        }

        return sniHostName;

    }

}