public class NtpMessage {
private static final NumberFormat numberFormat = new java.text.DecimalFormat(
"0.00");
public static void processResponse(TimeInfo info) {
NtpV3Packet message = info.getMessage();
int stratum = message.getStratum();
String refType;
if (stratum <= 0)
refType = "(Unspecified or Unavailable)";
else if (stratum == 1)
refType = "(Primary Reference; e.g., GPS)"; // GPS, radio clock,
// etc.
else
refType = "(Secondary Reference; e.g. via NTP or SNTP)";
// stratum should be 0..15...
System.out.println(" Stratum: " + stratum + " " + refType);
int version = message.getVersion();
int li = message.getLeapIndicator();
System.out.println(" leap=" + li + ", version=" + version
+ ", precision=" + message.getPrecision());
System.out.println(" mode: " + message.getModeName() + " ("
+ message.getMode() + ")");
int poll = message.getPoll();
// poll value typically btwn MINPOLL (4) and MAXPOLL (14)
System.out.println(" poll: "
+ (poll <= 0 ? 1 : (int) Math.pow(2, poll)) + " seconds"
+ " (2 ** " + poll + ")");
double disp = message.getRootDispersionInMillisDouble();
System.out.println(" rootdelay="
+ numberFormat.format(message.getRootDelayInMillisDouble())
+ ", rootdispersion(ms): " + numberFormat.format(disp));
int refId = message.getReferenceId();
String refAddr = NtpUtils.getHostAddress(refId);
String refName = null;
if (refId != 0) {
if (refAddr.equals("127.127.1.0")) {
refName = "LOCAL"; // This is the ref address for the Local
// Clock
} else if (stratum >= 2) {
// If reference id has 127.127 prefix then it uses its own
// reference clock
// defined in the form 127.127.clock-type.unit-num (e.g.
// 127.127.8.0 mode 5
// for GENERIC DCF77 AM; see refclock.htm from the NTP software
// distribution.
if (!refAddr.startsWith("127.127")) {
try {
InetAddress addr = InetAddress.getByName(refAddr);
String name = addr.getHostName();
if (name != null && !name.equals(refAddr))
refName = name;
} catch (UnknownHostException e) {
// some stratum-2 servers sync to ref clock device but
// fudge stratum level higher... (e.g. 2)
// ref not valid host maybe it's a reference clock name?
// otherwise just show the ref IP address.
refName = NtpUtils.getReferenceClock(message);
}
}
} else if (version >= 3 && (stratum == 0 || stratum == 1)) {
refName = NtpUtils.getReferenceClock(message);
// refname usually have at least 3 characters (e.g. GPS, WWV,
// LCL, etc.)
}
// otherwise give up on naming the beast...
}
if (refName != null && refName.length() > 1)
refAddr += " (" + refName + ")";
System.out.println(" Reference Identifier:\t" + refAddr);
TimeStamp refNtpTime = message.getReferenceTimeStamp();
System.out.println(" Reference Timestamp:\t" + refNtpTime + " "
+ refNtpTime.toDateString());
// Originate Time is time request sent by client (t1)
TimeStamp origNtpTime = message.getOriginateTimeStamp();
System.out.println(" Originate Timestamp:\t" + origNtpTime + " "
+ origNtpTime.toDateString());
long destTime = info.getReturnTime();
// Receive Time is time request received by server (t2)
TimeStamp rcvNtpTime = message.getReceiveTimeStamp();
System.out.println(" Receive Timestamp:\t" + rcvNtpTime + " "
+ rcvNtpTime.toDateString());
// Transmit time is time reply sent by server (t3)
TimeStamp xmitNtpTime = message.getTransmitTimeStamp();
System.out.println(" Transmit Timestamp:\t" + xmitNtpTime + " "
+ xmitNtpTime.toDateString());
// Destination time is time reply received by client (t4)
TimeStamp destNtpTime = TimeStamp.getNtpTime(destTime);