001 package 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: 1299238 $
026 */
027 public 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 }
068 int refId = message.getReferenceId();
069 if (refId == 0) {
070 return "";
071 }
072 StringBuilder buf = new StringBuilder(4);
073 // start at highest-order byte (0x4c434c00 -> LCL)
074 for (int shiftBits = 24; shiftBits >= 0; shiftBits -= 8)
075 {
076 char c = (char) ((refId >>> shiftBits) & 0xff);
077 if (c == 0) { // 0-terminated ASCII string
078 break;
079 }
080 if (!Character.isLetterOrDigit(c)) {
081 return "";
082 }
083 buf.append(c);
084 }
085 return buf.toString();
086 }
087
088 /***
089 * Return human-readable name of message mode type (RFC 1305).
090 *
091 * @param mode
092 * @return mode name
093 */
094 public static String getModeName(int mode)
095 {
096 switch (mode) {
097 case NtpV3Packet.MODE_RESERVED:
098 return "Reserved";
099 case NtpV3Packet.MODE_SYMMETRIC_ACTIVE:
100 return "Symmetric Active";
101 case NtpV3Packet.MODE_SYMMETRIC_PASSIVE:
102 return "Symmetric Passive";
103 case NtpV3Packet.MODE_CLIENT:
104 return "Client";
105 case NtpV3Packet.MODE_SERVER:
106 return "Server";
107 case NtpV3Packet.MODE_BROADCAST:
108 return "Broadcast";
109 case NtpV3Packet.MODE_CONTROL_MESSAGE:
110 return "Control";
111 case NtpV3Packet.MODE_PRIVATE:
112 return "Private";
113 default:
114 return "Unknown";
115 }
116 }
117
118 }