TestNtpPacket.java
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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
*
* https://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,
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* See the License for the specific language governing permissions and
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package org.apache.commons.net.ntp;
import static org.junit.jupiter.api.Assertions.assertThrows;
import java.net.DatagramPacket;
import org.junit.Assert;
import org.junit.Test;
public class TestNtpPacket {
// pre-canned NTP packet
// [version:3, mode:4, poll:4, refId=0x81531472, precision:-17, delay:100, dispersion(ms):51.605224609375,
// id:129.83.20.114, xmitTime:Thu, May 30 2013 17:46:01.295, etc. ]
static final byte[] ntpPacket = hexStringToByteArray("1c0304ef0000006400000d3681531472d552447fec1d6000d5524718ac49ba5ed55247194b6d9000d55247194b797000");
private static byte[] hexStringToByteArray(final String s) {
final int len = s.length();
final byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i + 1), 16));
}
return data;
}
@Test
public void testCreate() {
final NtpV3Packet message = new NtpV3Impl();
message.setLeapIndicator(0); // byte 0 [bit numbers 7-6]
message.setVersion(NtpV3Packet.VERSION_3); // byte 0 [bit numbers 5-4]
message.setMode(4); // byte 0 [bit numbers 3-0]
message.setStratum(3); // byte 1
message.setPoll(4); // byte 2
message.setPrecision(-17); // byte 3
message.setRootDelay(100); // bytes 4-7
message.setRootDispersion(3382); // bytes 8-11
message.setReferenceId(0x81531472); // byte 12-15
message.setReferenceTime(new TimeStamp(0xd552447fec1d6000L));
message.setOriginateTimeStamp(new TimeStamp(0xd5524718ac49ba5eL));
message.setReceiveTimeStamp(new TimeStamp(0xd55247194b6d9000L));
message.setTransmitTime(new TimeStamp(0xd55247194b797000L));
Assert.assertEquals(-17, message.getPrecision());
Assert.assertEquals(4, message.getPoll());
Assert.assertEquals(100, message.getRootDelay());
Assert.assertEquals(3382, message.getRootDispersion());
Assert.assertEquals(0x81531472, message.getReferenceId());
Assert.assertNotNull(message.getReferenceTimeStamp());
Assert.assertEquals("NTP", message.getType());
Assert.assertEquals("Server", message.getModeName());
Assert.assertEquals("129.83.20.114", message.getReferenceIdString());
Assert.assertEquals(51, message.getRootDispersionInMillis());
Assert.assertEquals(message.getRootDelay() / 65.536, message.getRootDelayInMillisDouble(), 1e-13);
final DatagramPacket dp = message.getDatagramPacket(); // this creates a new datagram
Assert.assertNotNull(dp);
Assert.assertEquals(48, dp.getLength()); // fixed 48-byte length
final NtpV3Packet message2 = new NtpV3Impl();
final DatagramPacket dp2 = new DatagramPacket(ntpPacket, ntpPacket.length);
message2.setDatagramPacket(dp2);
Assert.assertEquals(message2, message);
Assert.assertEquals(message2.hashCode(), message.hashCode());
Assert.assertEquals(message2.toString(), message.toString());
}
@Test
public void testCreateAndSetByte0() {
// LI + VN + Mode all part of first byte -- make sure set order does not matter
final NtpV3Packet message = new NtpV3Impl();
message.setLeapIndicator(2);
message.setMode(4);
message.setVersion(NtpV3Packet.VERSION_3);
Assert.assertEquals(4, message.getMode());
Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
Assert.assertEquals(2, message.getLeapIndicator());
message.setLeapIndicator(2);
message.setVersion(NtpV3Packet.VERSION_3);
message.setMode(4);
Assert.assertEquals(4, message.getMode());
Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
Assert.assertEquals(2, message.getLeapIndicator());
message.setMode(4);
message.setLeapIndicator(2);
message.setVersion(NtpV3Packet.VERSION_3);
Assert.assertEquals(4, message.getMode());
Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
Assert.assertEquals(2, message.getLeapIndicator());
message.setMode(4);
message.setVersion(NtpV3Packet.VERSION_3);
message.setLeapIndicator(2);
Assert.assertEquals(4, message.getMode());
Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
Assert.assertEquals(2, message.getLeapIndicator());
message.setVersion(NtpV3Packet.VERSION_3);
message.setMode(4);
message.setLeapIndicator(2);
Assert.assertEquals(4, message.getMode());
Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
Assert.assertEquals(2, message.getLeapIndicator());
message.setVersion(NtpV3Packet.VERSION_3);
message.setLeapIndicator(2);
message.setMode(4);
Assert.assertEquals(4, message.getMode());
Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
Assert.assertEquals(2, message.getLeapIndicator());
}
@Test
public void testCreateFromBadPacket() {
final NtpV3Packet message = new NtpV3Impl();
final DatagramPacket dp = new DatagramPacket(ntpPacket, ntpPacket.length - 4); // drop 4-bytes from packet
assertThrows(IllegalArgumentException.class, () -> message.setDatagramPacket(dp));
}
@Test
public void testCreateFromBytes() {
final NtpV3Packet message = new NtpV3Impl();
final DatagramPacket dp = new DatagramPacket(ntpPacket, ntpPacket.length);
message.setDatagramPacket(dp);
Assert.assertEquals(4, message.getMode());
}
@Test
public void testCreateFromNullPacket() {
final NtpV3Packet message = new NtpV3Impl();
assertThrows(IllegalArgumentException.class, () -> message.setDatagramPacket(null));
}
@Test
public void testCreateNtpV4() {
final NtpV3Packet message = new NtpV3Impl();
message.setVersion(NtpV3Packet.VERSION_4);
message.setStratum(3);
message.setReferenceId(0x81531472);
// force hex-string reference id string
Assert.assertEquals("81531472", message.getReferenceIdString());
message.setVersion(NtpV3Packet.VERSION_4);
message.setStratum(1);
message.setReferenceId(0x55534E4F); // USNO
// force raw-string reference id string
Assert.assertEquals("USNO", message.getReferenceIdString());
message.setReferenceId(0x47505300); // GPS
Assert.assertEquals("GPS", message.getReferenceIdString());
}
@Test
public void testEquals() {
final NtpV3Packet message1 = new NtpV3Impl();
final DatagramPacket dp = new DatagramPacket(ntpPacket, ntpPacket.length);
message1.setDatagramPacket(dp);
final NtpV3Packet message2 = new NtpV3Impl();
message2.setDatagramPacket(dp);
Assert.assertEquals("hashCode", message1.hashCode(), message2.hashCode());
Assert.assertEquals(message1, message2);
// now change the packet to force equals() => false
message2.setMode(2);
Assert.assertTrue(message1.getMode() != message2.getMode());
Assert.assertNotEquals(message1, message2);
final NtpV3Packet message3 = null;
Assert.assertNotEquals(message3, message1);
}
}