001package org.apache.commons.net.ntp;
002/*
003 * Licensed to the Apache Software Foundation (ASF) under one or more
004 * contributor license agreements.  See the NOTICE file distributed with
005 * this work for additional information regarding copyright ownership.
006 * The ASF licenses this file to You under the Apache License, Version 2.0
007 * (the "License"); you may not use this file except in compliance with
008 * the License.  You may obtain a copy of the License at
009 *
010 *      http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019
020/***
021 * Common NtpUtils Helper class.
022 *
023 * @author Jason Mathews, MITRE Corp
024 *
025 * @version $Revision: 489397 $ $Date: 2006-12-21 16:28:51 +0000 (Thu, 21 Dec 2006) $
026 */
027public final class NtpUtils {
028
029    /***
030      * Returns 32-bit integer address to IPv4 address string "%d.%d.%d.%d" format.
031      *
032      * @param address  the 32-bit address
033      * @return  the raw IP address in a string format.
034      */
035     public static String getHostAddress(int address)
036     {
037          return ((address >>> 24) & 0xFF) + "." +
038                 ((address >>> 16) & 0xFF) + "." +
039                 ((address >>>  8) & 0xFF) + "." +
040                 ((address >>>  0) & 0xFF);
041     }
042
043    /***
044     * Returns NTP packet reference identifier as IP address.
045     *
046     * @param packet  NTP packet
047     * @return  the packet reference id (as IP address) in "%d.%d.%d.%d" format.
048     */
049     public static String getRefAddress(NtpV3Packet packet)
050     {
051         int address = (packet == null) ? 0 : packet.getReferenceId();
052         return getHostAddress(address);
053     }
054
055    /***
056     * Get refId as reference clock string (e.g. GPS, WWV, LCL). If string is
057     * invalid (non-ASCII character) then returns empty string "".
058     * For details refer to the <A HREF="http://www.eecis.udel.edu/~mills/ntp/html/refclock.html#list">Comprehensive
059     * List of Clock Drivers</A>.
060     *
061     * @param message
062     * @return reference clock string if primary NTP server
063     */
064    public static String getReferenceClock(NtpV3Packet message) {
065        if (message == null)
066            return "";
067        int refId = message.getReferenceId();
068        if (refId == 0)
069            return "";
070        StringBuffer buf = new StringBuffer(4);
071        // start at highest-order byte (0x4c434c00 -> LCL)
072        for (int shiftBits = 24; shiftBits >= 0; shiftBits -= 8)
073        {
074            char c = (char) ((refId >>> shiftBits) & 0xff);
075            if (c == 0) break; // 0-terminated ASCII string
076            if (!Character.isLetterOrDigit(c))
077                return "";
078            buf.append(c);
079        }
080        return buf.toString();
081    }
082
083    /***
084     * Return human-readable name of message mode type (RFC 1305).
085     *
086     * @param mode
087     * @return mode name
088     */
089    public static String getModeName(int mode)
090    {
091        switch (mode) {
092            case NtpV3Packet.MODE_RESERVED:
093                return "Reserved";
094            case NtpV3Packet.MODE_SYMMETRIC_ACTIVE:
095                return "Symmetric Active";
096            case NtpV3Packet.MODE_SYMMETRIC_PASSIVE:
097                return "Symmetric Passive";
098            case NtpV3Packet.MODE_CLIENT:
099                return "Client";
100            case NtpV3Packet.MODE_SERVER:
101                return "Server";
102            case NtpV3Packet.MODE_BROADCAST:
103                return "Broadcast";
104            case NtpV3Packet.MODE_CONTROL_MESSAGE:
105                return "Control";
106            case NtpV3Packet.MODE_PRIVATE:
107                return "Private";
108            default:
109                return "Unknown";
110        }
111    }
112
113}