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110 lines (104 loc) · 3.46 KB
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package nts;
/** Common NtpUtils Helper class. */
public final class NtpUtils {
/**
* Returns 32-bit integer address to IPv4 address string "%d.%d.%d.%d" format.
*
* @param address the 32-bit address
* @return the raw IP address in a string format.
*/
public static String getHostAddress(final int address) {
return (address >>> 24 & 0xFF)
+ "."
+ (address >>> 16 & 0xFF)
+ "."
+ (address >>> 8 & 0xFF)
+ "."
+ (address >>> 0 & 0xFF);
}
/**
* Return human-readable name of message mode type (RFC 1305).
*
* @param mode the mode type
* @return mode name
*/
public static String getModeName(final int mode) {
switch (mode) {
case NtpV3Packet.MODE_RESERVED:
return "Reserved";
case NtpV3Packet.MODE_SYMMETRIC_ACTIVE:
return "Symmetric Active";
case NtpV3Packet.MODE_SYMMETRIC_PASSIVE:
return "Symmetric Passive";
case NtpV3Packet.MODE_CLIENT:
return "Client";
case NtpV3Packet.MODE_SERVER:
return "Server";
case NtpV3Packet.MODE_BROADCAST:
return "Broadcast";
case NtpV3Packet.MODE_CONTROL_MESSAGE:
return "Control";
case NtpV3Packet.MODE_PRIVATE:
return "Private";
default:
return "Unknown";
}
}
/**
* Returns NTP packet reference identifier as IP address.
*
* @param packet NTP packet
* @return the packet reference id (as IP address) in "%d.%d.%d.%d" format.
*/
public static String getRefAddress(final NtpV3Packet packet) {
final int address = packet == null ? 0 : packet.getReferenceId();
return getHostAddress(address);
}
/**
* 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 the <A
* HREF="http://www.eecis.udel.edu/~mills/ntp/html/refclock.html#list">Comprehensive List of Clock
* Drivers</A>.
*
* @param message the message to check
* @return reference clock string if primary NTP server
*/
public static String getReferenceClock(final NtpV3Packet message) {
if (message == null) {
return "";
}
final int refId = message.getReferenceId();
if (refId == 0) {
return "";
}
final StringBuilder buf = new StringBuilder(4);
// start at highest-order byte (0x4c434c00 -> LCL)
for (int shiftBits = 24; shiftBits >= 0; shiftBits -= 8) {
final char c = (char) (refId >>> shiftBits & 0xff);
if (c == 0) { // 0-terminated ASCII string
break;
}
if (!Character.isLetterOrDigit(c)) {
return "";
}
buf.append(c);
}
return buf.toString();
}
}