1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.net.ntp; 19 20 /** 21 * Common NtpUtils Helper class. 22 */ 23 public final class NtpUtils { 24 25 /** 26 * Returns 32-bit integer address to IPv4 address string "%d.%d.%d.%d" format. 27 * 28 * @param address the 32-bit address 29 * @return the raw IP address in a string format. 30 */ 31 public static String getHostAddress(final int address) { 32 return (address >>> 24 & 0xFF) + "." + (address >>> 16 & 0xFF) + "." + (address >>> 8 & 0xFF) + "." + (address >>> 0 & 0xFF); 33 } 34 35 /** 36 * Return human-readable name of message mode type (RFC 1305). 37 * 38 * @param mode the mode type 39 * @return mode name 40 */ 41 public static String getModeName(final int mode) { 42 switch (mode) { 43 case NtpV3Packet.MODE_RESERVED: 44 return "Reserved"; 45 case NtpV3Packet.MODE_SYMMETRIC_ACTIVE: 46 return "Symmetric Active"; 47 case NtpV3Packet.MODE_SYMMETRIC_PASSIVE: 48 return "Symmetric Passive"; 49 case NtpV3Packet.MODE_CLIENT: 50 return "Client"; 51 case NtpV3Packet.MODE_SERVER: 52 return "Server"; 53 case NtpV3Packet.MODE_BROADCAST: 54 return "Broadcast"; 55 case NtpV3Packet.MODE_CONTROL_MESSAGE: 56 return "Control"; 57 case NtpV3Packet.MODE_PRIVATE: 58 return "Private"; 59 default: 60 return "Unknown"; 61 } 62 } 63 64 /** 65 * Returns NTP packet reference identifier as IP address. 66 * 67 * @param packet NTP packet 68 * @return the packet reference id (as IP address) in "%d.%d.%d.%d" format. 69 */ 70 public static String getRefAddress(final NtpV3Packet packet) { 71 final int address = packet == null ? 0 : packet.getReferenceId(); 72 return getHostAddress(address); 73 } 74 75 /** 76 * Gets refId as reference clock string (e.g. GPS, WWV, LCL). If string is invalid (non-ASCII character) then returns empty string "". For details refer to 77 * the <A HREF="http://www.eecis.udel.edu/~mills/ntp/html/refclock.html#list">Comprehensive List of Clock Drivers</A>. 78 * 79 * @param message the message to check 80 * @return reference clock string if primary NTP server 81 */ 82 public static String getReferenceClock(final NtpV3Packet message) { 83 if (message == null) { 84 return ""; 85 } 86 final int refId = message.getReferenceId(); 87 if (refId == 0) { 88 return ""; 89 } 90 final StringBuilder buf = new StringBuilder(4); 91 // start at highest-order byte (0x4c434c00 -> LCL) 92 for (int shiftBits = 24; shiftBits >= 0; shiftBits -= 8) { 93 final char c = (char) (refId >>> shiftBits & 0xff); 94 if (c == 0) { // 0-terminated ASCII string 95 break; 96 } 97 if (!Character.isLetterOrDigit(c)) { 98 return ""; 99 } 100 buf.append(c); 101 } 102 return buf.toString(); 103 } 104 105 }