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> Date: Fri, 13 Aug 2004 15:58:30 +1200 (NZST)

Browse Source 
> Message-ID: <1776.202.37.75.101.1092369510.squirrel@202.37.75.101>
> From: adam@adambuckley.net
> To: jrandom@i2p.net
>
> [...]
>
> I hereby authorize my NtpClient.java and NtpMessage.java code to be
> redistributed under the BSD license for the purpose of integration with
> the I2P project, providing that I am credited as the original author of
> the code.
>
> [...]
w00t!  adam++
code migrated into core/java/src/net/i2p/time, integrated with Clock,
dropping that whole ugly pass-the-time-through-URL, and hence dropped
support for :7655/setTime.
New router.config properties to control the timestamper:
  time.sntpServerList=pool.ntp.org,pool.ntp.org,pool.ntp.org
  time.queryFrequencyMs=300000
  time.disabled=false
So, to disable, add time.disabled=true to your router.config.  It is
enabled by default.
Default router.config and startup scripts updated accordingly (since
timestamper.jar is now gone)
This commit is contained in:
jrandom
2004-08-13 21:15:22 +00:00
committed by zzz
parent 3c9b0273d4
commit 352396bdc2
17 changed files with 287 additions and 313 deletions
Download Patch File Download Diff File Expand all files Collapse all files

158
core/java/src/net/i2p/time/NtpClient.java Normal file
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package net.i2p.time;
/*
* Copyright (c) 2004, Adam Buckley
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of Adam Buckley nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
/**
* NtpClient - an NTP client for Java. This program connects to an NTP server
* and prints the response to the console.
*
* The local clock offset calculation is implemented according to the SNTP
* algorithm specified in RFC 2030.
*
* Note that on windows platforms, the curent time-of-day timestamp is limited
* to an resolution of 10ms and adversely affects the accuracy of the results.
*
* @author Adam Buckley
* (minor refactoring by jrandom)
*/
public class NtpClient {
/** difference between the unix epoch and jan 1 1900 (NTP uses that) */
private final static double SECONDS_1900_TO_EPOCH = 2208988800.0;
private final static int NTP_PORT = 123;
/**
* Query the ntp servers, returning the current time from first one we find
*
* @return milliseconds since january 1, 1970 (UTC)
* @throws IllegalArgumentException if none of the servers are reachable
*/
public static long currentTime(String serverNames[]) {
if (serverNames == null)
throw new IllegalArgumentException("No NTP servers specified");
for (int i = 0; i < serverNames.length; i++) {
long now = currentTime(serverNames[i]);
if (now > 0)
return now;
}
throw new IllegalArgumentException("No reachable NTP servers specified");
}
/**
* Query the given NTP server, returning the current internet time
*
* @return milliseconds since january 1, 1970 (UTC), or -1 on error
*/
public static long currentTime(String serverName) {
try {
// Send request
DatagramSocket socket = new DatagramSocket();
InetAddress address = InetAddress.getByName(serverName);
byte[] buf = new NtpMessage().toByteArray();
DatagramPacket packet = new DatagramPacket(buf, buf.length, address, NTP_PORT);
// Set the transmit timestamp *just* before sending the packet
// ToDo: Does this actually improve performance or not?
NtpMessage.encodeTimestamp(packet.getData(), 40,
(System.currentTimeMillis()/1000.0)
+ SECONDS_1900_TO_EPOCH);
socket.send(packet);
// Get response
packet = new DatagramPacket(buf, buf.length);
socket.setSoTimeout(10*1000);
try {
socket.receive(packet);
} catch (InterruptedIOException iie) {
socket.close();
return -1;
}
// Immediately record the incoming timestamp
double destinationTimestamp = (System.currentTimeMillis()/1000.0) + SECONDS_1900_TO_EPOCH;
// Process response
NtpMessage msg = new NtpMessage(packet.getData());
double roundTripDelay = (destinationTimestamp-msg.originateTimestamp) -
(msg.receiveTimestamp-msg.transmitTimestamp);
double localClockOffset = ((msg.receiveTimestamp - msg.originateTimestamp) +
(msg.transmitTimestamp - destinationTimestamp)) / 2;
socket.close();
//System.out.println("host: " + serverName + " rtt: " + roundTripDelay + " offset: " + localClockOffset + " seconds");
return (long)(System.currentTimeMillis() + localClockOffset*1000);
} catch (IOException ioe) {
ioe.printStackTrace();
return -1;
}
}
public static void main(String[] args) throws IOException {
// Process command-line args
if(args.length <= 0) {
printUsage();
return;
// args = new String[] { "ntp1.sth.netnod.se", "ntp2.sth.netnod.se" };
}
long now = currentTime(args);
System.out.println("Current time: " + new java.util.Date(now));
}
/**
* Prints usage
*/
static void printUsage() {
System.out.println(
"NtpClient - an NTP client for Java.\n" +
"\n" +
"This program connects to an NTP server and prints the current time to the console.\n" +
"\n" +
"\n" +
"Usage: java NtpClient server[ server]*\n" +
"\n" +
"\n" +
"This program is copyright (c) Adam Buckley 2004 and distributed under the terms\n" +
"of the GNU General Public License. This program is distributed in the hope\n" +
"that it will be useful, but WITHOUT ANY WARRANTY; without even the implied\n" +
"warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU\n" +
"General Public License available at http://www.gnu.org/licenses/gpl.html for\n" +
"more details.");
}
}

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core/java/src/net/i2p/time/NtpMessage.java Normal file
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package net.i2p.time;
/*
* Copyright (c) 2004, Adam Buckley
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of Adam Buckley nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* This class represents a NTP message, as specified in RFC 2030. The message
* format is compatible with all versions of NTP and SNTP.
*
* This class does not support the optional authentication protocol, and
* ignores the key ID and message digest fields.
*
* For convenience, this class exposes message values as native Java types, not
* the NTP-specified data formats. For example, timestamps are
* stored as doubles (as opposed to the NTP unsigned 64-bit fixed point
* format).
*
* However, the contructor NtpMessage(byte[]) and the method toByteArray()
* allow the import and export of the raw NTP message format.
*
*
* Usage example
*
* // Send message
* DatagramSocket socket = new DatagramSocket();
* InetAddress address = InetAddress.getByName("ntp.cais.rnp.br");
* byte[] buf = new NtpMessage().toByteArray();
* DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 123);
* socket.send(packet);
*
* // Get response
* socket.receive(packet);
* System.out.println(msg.toString());
*
* Comments for member variables are taken from RFC2030 by David Mills,
* University of Delaware.
*
* Number format conversion code in NtpMessage(byte[] array) and toByteArray()
* inspired by http://www.pps.jussieu.fr/~jch/enseignement/reseaux/
* NTPMessage.java which is copyright (c) 2003 by Juliusz Chroboczek
*
* @author Adam Buckley
*/
public class NtpMessage {
/**
* This is a two-bit code warning of an impending leap second to be
* inserted/deleted in the last minute of the current day. It's values
* may be as follows:
*
* Value Meaning
* ----- -------
* 0 no warning
* 1 last minute has 61 seconds
* 2 last minute has 59 seconds)
* 3 alarm condition (clock not synchronized)
*/
public byte leapIndicator = 0;
/**
* This value indicates the NTP/SNTP version number. The version number
* is 3 for Version 3 (IPv4 only) and 4 for Version 4 (IPv4, IPv6 and OSI).
* If necessary to distinguish between IPv4, IPv6 and OSI, the
* encapsulating context must be inspected.
*/
public byte version = 3;
/**
* This value indicates the mode, with values defined as follows:
*
* Mode Meaning
* ---- -------
* 0 reserved
* 1 symmetric active
* 2 symmetric passive
* 3 client
* 4 server
* 5 broadcast
* 6 reserved for NTP control message
* 7 reserved for private use
*
* In unicast and anycast modes, the client sets this field to 3 (client)
* in the request and the server sets it to 4 (server) in the reply. In
* multicast mode, the server sets this field to 5 (broadcast).
*/
public byte mode = 0;
/**
* This value indicates the stratum level of the local clock, with values
* defined as follows:
*
* Stratum Meaning
* ----------------------------------------------
* 0 unspecified or unavailable
* 1 primary reference (e.g., radio clock)
* 2-15 secondary reference (via NTP or SNTP)
* 16-255 reserved
*/
public short stratum = 0;
/**
* This value indicates the maximum interval between successive messages,
* in seconds to the nearest power of two. The values that can appear in
* this field presently range from 4 (16 s) to 14 (16284 s); however, most
* applications use only the sub-range 6 (64 s) to 10 (1024 s).
*/
public byte pollInterval = 0;
/**
* This value indicates the precision of the local clock, in seconds to
* the nearest power of two. The values that normally appear in this field
* range from -6 for mains-frequency clocks to -20 for microsecond clocks
* found in some workstations.
*/
public byte precision = 0;
/**
* This value indicates the total roundtrip delay to the primary reference
* source, in seconds. Note that this variable can take on both positive
* and negative values, depending on the relative time and frequency
* offsets. The values that normally appear in this field range from
* negative values of a few milliseconds to positive values of several
* hundred milliseconds.
*/
public double rootDelay = 0;
/**
* This value indicates the nominal error relative to the primary reference
* source, in seconds. The values that normally appear in this field
* range from 0 to several hundred milliseconds.
*/
public double rootDispersion = 0;
/**
* This is a 4-byte array identifying the particular reference source.
* In the case of NTP Version 3 or Version 4 stratum-0 (unspecified) or
* stratum-1 (primary) servers, this is a four-character ASCII string, left
* justified and zero padded to 32 bits. In NTP Version 3 secondary
* servers, this is the 32-bit IPv4 address of the reference source. In NTP
* Version 4 secondary servers, this is the low order 32 bits of the latest
* transmit timestamp of the reference source. NTP primary (stratum 1)
* servers should set this field to a code identifying the external
* reference source according to the following list. If the external
* reference is one of those listed, the associated code should be used.
* Codes for sources not listed can be contrived as appropriate.
*
* Code External Reference Source
* ---- -------------------------
* LOCL uncalibrated local clock used as a primary reference for
* a subnet without external means of synchronization
* PPS atomic clock or other pulse-per-second source
* individually calibrated to national standards
* ACTS NIST dialup modem service
* USNO USNO modem service
* PTB PTB (Germany) modem service
* TDF Allouis (France) Radio 164 kHz
* DCF Mainflingen (Germany) Radio 77.5 kHz
* MSF Rugby (UK) Radio 60 kHz
* WWV Ft. Collins (US) Radio 2.5, 5, 10, 15, 20 MHz
* WWVB Boulder (US) Radio 60 kHz
* WWVH Kaui Hawaii (US) Radio 2.5, 5, 10, 15 MHz
* CHU Ottawa (Canada) Radio 3330, 7335, 14670 kHz
* LORC LORAN-C radionavigation system
* OMEG OMEGA radionavigation system
* GPS Global Positioning Service
* GOES Geostationary Orbit Environment Satellite
*/
public byte[] referenceIdentifier = {0, 0, 0, 0};
/**
* This is the time at which the local clock was last set or corrected, in
* seconds since 00:00 1-Jan-1900.
*/
public double referenceTimestamp = 0;
/**
* This is the time at which the request departed the client for the
* server, in seconds since 00:00 1-Jan-1900.
*/
public double originateTimestamp = 0;
/**
* This is the time at which the request arrived at the server, in seconds
* since 00:00 1-Jan-1900.
*/
public double receiveTimestamp = 0;
/**
* This is the time at which the reply departed the server for the client,
* in seconds since 00:00 1-Jan-1900.
*/
public double transmitTimestamp = 0;
/**
* Constructs a new NtpMessage from an array of bytes.
*/
public NtpMessage(byte[] array) {
// See the packet format diagram in RFC 2030 for details
leapIndicator = (byte) ((array[0] >> 6) & 0x3);
version = (byte) ((array[0] >> 3) & 0x7);
mode = (byte) (array[0] & 0x7);
stratum = unsignedByteToShort(array[1]);
pollInterval = array[2];
precision = array[3];
rootDelay = (array[4] * 256.0) +
unsignedByteToShort(array[5]) +
(unsignedByteToShort(array[6]) / 256.0) +
(unsignedByteToShort(array[7]) / 65536.0);
rootDispersion = (unsignedByteToShort(array[8]) * 256.0) +
unsignedByteToShort(array[9]) +
(unsignedByteToShort(array[10]) / 256.0) +
(unsignedByteToShort(array[11]) / 65536.0);
referenceIdentifier[0] = array[12];
referenceIdentifier[1] = array[13];
referenceIdentifier[2] = array[14];
referenceIdentifier[3] = array[15];
referenceTimestamp = decodeTimestamp(array, 16);
originateTimestamp = decodeTimestamp(array, 24);
receiveTimestamp = decodeTimestamp(array, 32);
transmitTimestamp = decodeTimestamp(array, 40);
}
/**
* Constructs a new NtpMessage in client -> server mode, and sets the
* transmit timestamp to the current time.
*/
public NtpMessage() {
// Note that all the other member variables are already set with
// appropriate default values.
this.mode = 3;
this.transmitTimestamp = (System.currentTimeMillis()/1000.0) + 2208988800.0;
}
/**
* This method constructs the data bytes of a raw NTP packet.
*/
public byte[] toByteArray() {
// All bytes are automatically set to 0
byte[] p = new byte[48];
p[0] = (byte) (leapIndicator << 6 | version << 3 | mode);
p[1] = (byte) stratum;
p[2] = (byte) pollInterval;
p[3] = (byte) precision;
// root delay is a signed 16.16-bit FP, in Java an int is 32-bits
int l = (int) (rootDelay * 65536.0);
p[4] = (byte) ((l >> 24) & 0xFF);
p[5] = (byte) ((l >> 16) & 0xFF);
p[6] = (byte) ((l >> 8) & 0xFF);
p[7] = (byte) (l & 0xFF);
// root dispersion is an unsigned 16.16-bit FP, in Java there are no
// unsigned primitive types, so we use a long which is 64-bits
long ul = (long) (rootDispersion * 65536.0);
p[8] = (byte) ((ul >> 24) & 0xFF);
p[9] = (byte) ((ul >> 16) & 0xFF);
p[10] = (byte) ((ul >> 8) & 0xFF);
p[11] = (byte) (ul & 0xFF);
p[12] = referenceIdentifier[0];
p[13] = referenceIdentifier[1];
p[14] = referenceIdentifier[2];
p[15] = referenceIdentifier[3];
encodeTimestamp(p, 16, referenceTimestamp);
encodeTimestamp(p, 24, originateTimestamp);
encodeTimestamp(p, 32, receiveTimestamp);
encodeTimestamp(p, 40, transmitTimestamp);
return p;
}
/**
* Returns a string representation of a NtpMessage
*/
public String toString() {
String precisionStr = new DecimalFormat("0.#E0").format(Math.pow(2, precision));
return "Leap indicator: " + leapIndicator + "\n" +
"Version: " + version + "\n" +
"Mode: " + mode + "\n" +
"Stratum: " + stratum + "\n" +
"Poll: " + pollInterval + "\n" +
"Precision: " + precision + " (" + precisionStr + " seconds)\n" +
"Root delay: " + new DecimalFormat("0.00").format(rootDelay*1000) + " ms\n" +
"Root dispersion: " + new DecimalFormat("0.00").format(rootDispersion*1000) + " ms\n" +
"Reference identifier: " + referenceIdentifierToString(referenceIdentifier, stratum, version) + "\n" +
"Reference timestamp: " + timestampToString(referenceTimestamp) + "\n" +
"Originate timestamp: " + timestampToString(originateTimestamp) + "\n" +
"Receive timestamp: " + timestampToString(receiveTimestamp) + "\n" +
"Transmit timestamp: " + timestampToString(transmitTimestamp);
}
/**
* Converts an unsigned byte to a short. By default, Java assumes that
* a byte is signed.
*/
public static short unsignedByteToShort(byte b) {
if((b & 0x80)==0x80)
return (short) (128 + (b & 0x7f));
else
return (short) b;
}
/**
* Will read 8 bytes of a message beginning at <code>pointer</code>
* and return it as a double, according to the NTP 64-bit timestamp
* format.
*/
public static double decodeTimestamp(byte[] array, int pointer) {
double r = 0.0;
for(int i=0; i<8; i++) {
r += unsignedByteToShort(array[pointer+i]) * Math.pow(2, (3-i)*8);
}
return r;
}
/**
* Encodes a timestamp in the specified position in the message
*/
public static void encodeTimestamp(byte[] array, int pointer, double timestamp) {
// Converts a double into a 64-bit fixed point
for(int i=0; i<8; i++) {
// 2^24, 2^16, 2^8, .. 2^-32
double base = Math.pow(2, (3-i)*8);
// Capture byte value
array[pointer+i] = (byte) (timestamp / base);
// Subtract captured value from remaining total
timestamp = timestamp - (double) (unsignedByteToShort(array[pointer+i]) * base);
}
// From RFC 2030: It is advisable to fill the non-significant
// low order bits of the timestamp with a random, unbiased
// bitstring, both to avoid systematic roundoff errors and as
// a means of loop detection and replay detection.
array[7+pointer] = (byte) (Math.random()*255.0);
}
/**
* Returns a timestamp (number of seconds since 00:00 1-Jan-1900) as a
* formatted date/time string.
*/
public static String timestampToString(double timestamp) {
if(timestamp==0) return "0";
// timestamp is relative to 1900, utc is used by Java and is relative
// to 1970
double utc = timestamp - (2208988800.0);
// milliseconds
long ms = (long) (utc * 1000.0);
// date/time
String date = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss").format(new Date(ms));
// fraction
double fraction = timestamp - ((long) timestamp);
String fractionSting = new DecimalFormat(".000000").format(fraction);
return date + fractionSting;
}
/**
* Returns a string representation of a reference identifier according
* to the rules set out in RFC 2030.
*/
public static String referenceIdentifierToString(byte[] ref, short stratum, byte version) {
// From the RFC 2030:
// In the case of NTP Version 3 or Version 4 stratum-0 (unspecified)
// or stratum-1 (primary) servers, this is a four-character ASCII
// string, left justified and zero padded to 32 bits.
if(stratum==0 || stratum==1) {
return new String(ref);
}
// In NTP Version 3 secondary servers, this is the 32-bit IPv4
// address of the reference source.
else if(version==3) {
return unsignedByteToShort(ref[0]) + "." +
unsignedByteToShort(ref[1]) + "." +
unsignedByteToShort(ref[2]) + "." +
unsignedByteToShort(ref[3]);
}
// In NTP Version 4 secondary servers, this is the low order 32 bits
// of the latest transmit timestamp of the reference source.
else if(version==4) {
return "" + ((unsignedByteToShort(ref[0]) / 256.0) +
(unsignedByteToShort(ref[1]) / 65536.0) +
(unsignedByteToShort(ref[2]) / 16777216.0) +
(unsignedByteToShort(ref[3]) / 4294967296.0));
}
return "";
}
}

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core/java/src/net/i2p/time/Timestamper.java Normal file
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package net.i2p.time;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import net.i2p.I2PAppContext;
import net.i2p.util.I2PThread;
import net.i2p.util.Log;
/**
* Periodically query a series of NTP servers and update any associated
* listeners. It tries the NTP servers in order, contacting them using
* SNTP (UDP port 123). By default, it does this every 5 minutes,
* forever.
*/
public class Timestamper implements Runnable {
private I2PAppContext _context;
private Log _log;
private List _servers;
private List _listeners;
private int _queryFrequency;
private boolean _disabled;
private static final int DEFAULT_QUERY_FREQUENCY = 5*60*1000;
private static final String DEFAULT_SERVER_LIST = "pool.ntp.org, pool.ntp.org";
private static final boolean DEFAULT_DISABLED = false;
public static final String PROP_QUERY_FREQUENCY = "time.queryFrequencyMs";
public static final String PROP_SERVER_LIST = "time.sntpServerList";
public static final String PROP_DISABLED = "time.disabled";
public Timestamper(I2PAppContext ctx) {
this(ctx, null);
}
public Timestamper(I2PAppContext ctx, UpdateListener lsnr) {
_context = ctx;
_servers = new ArrayList(1);
_listeners = new ArrayList(1);
if (lsnr != null)
_listeners.add(lsnr);
updateConfig();
startTimestamper();
}
public int getServerCount() {
synchronized (_servers) {
return _servers.size();
}
}
public String getServer(int index) {
synchronized (_servers) {
return (String)_servers.get(index);
}
}
public int getQueryFrequencyMs() { return _queryFrequency; }
public boolean getIsDisabled() { return _disabled; }
public void addListener(UpdateListener lsnr) {
synchronized (_listeners) {
_listeners.add(lsnr);
}
}
public void removeListener(UpdateListener lsnr) {
synchronized (_listeners) {
_listeners.remove(lsnr);
}
}
public int getListenerCount() {
synchronized (_listeners) {
return _listeners.size();
}
}
public UpdateListener getListener(int index) {
synchronized (_listeners) {
return (UpdateListener)_listeners.get(index);
}
}
private void startTimestamper() {
I2PThread t = new I2PThread(this, "Timestamper");
t.setPriority(I2PThread.MIN_PRIORITY);
t.start();
}
public void run() {
try { Thread.sleep(1000); } catch (InterruptedException ie) {}
_log = _context.logManager().getLog(Timestamper.class);
if (_log.shouldLog(Log.INFO))
_log.info("Starting timestamper");
if (_log.shouldLog(Log.INFO))
_log.info("Starting up timestamper");
try {
while (true) {
if (!_disabled) {
String serverList[] = null;
synchronized (_servers) {
serverList = new String[_servers.size()];
for (int i = 0; i < serverList.length; i++)
serverList[i] = (String)_servers.get(i);
}
if (_log.shouldLog(Log.DEBUG))
_log.debug("Querying servers " + _servers);
try {
long now = NtpClient.currentTime(serverList);
if (_log.shouldLog(Log.DEBUG))
_log.debug("Stamp time");
stampTime(now);
} catch (IllegalArgumentException iae) {
_log.log(Log.CRIT, "Unable to reach any of the NTP servers - network disconnected?");
}
}
updateConfig();
try { Thread.sleep(_queryFrequency); } catch (InterruptedException ie) {}
}
} catch (Throwable t) {
_log.log(Log.CRIT, "Timestamper died!", t);
}
}
/**
* Send an HTTP request to a given URL specifying the current time
*/
private void stampTime(long now) {
synchronized (_listeners) {
for (int i = 0; i < _listeners.size(); i++) {
UpdateListener lsnr = (UpdateListener)_listeners.get(i);
lsnr.setNow(now);
}
}
}
/**
* Reload all the config elements from the appContext
*
*/
private void updateConfig() {
String serverList = _context.getProperty(PROP_SERVER_LIST);
if ( (serverList == null) || (serverList.trim().length() <= 0) )
serverList = DEFAULT_SERVER_LIST;
synchronized (_servers) {
StringTokenizer tok = new StringTokenizer(serverList, ",");
while (tok.hasMoreTokens()) {
String val = (String)tok.nextToken();
val = val.trim();
if (val.length() > 0)
_servers.add(val);
}
}
String freq = _context.getProperty(PROP_QUERY_FREQUENCY);
if ( (freq == null) || (freq.trim().length() <= 0) )
freq = DEFAULT_QUERY_FREQUENCY + "";
try {
int ms = Integer.parseInt(freq);
if (ms > 60*1000) {
_queryFrequency = ms;
} else {
if ( (_log != null) && (_log.shouldLog(Log.ERROR)) )
_log.error("Query frequency once every " + ms + "ms is too fast!");
_queryFrequency = DEFAULT_QUERY_FREQUENCY;
}
} catch (NumberFormatException nfe) {
if ( (_log != null) && (_log.shouldLog(Log.WARN)) )
_log.warn("Invalid query frequency [" + freq + "], falling back on " + DEFAULT_QUERY_FREQUENCY);
_queryFrequency = DEFAULT_QUERY_FREQUENCY;
}
String disabled = _context.getProperty(PROP_DISABLED);
if (disabled == null)
disabled = DEFAULT_DISABLED + "";
_disabled = Boolean.getBoolean(disabled);
}
/**
* Interface to receive update notifications for when we query the time
*
*/
public interface UpdateListener {
/**
* The time has been queried and we have a current value for 'now'
*
*/
public void setNow(long now);
}
}

8
core/java/src/net/i2p/util/Clock.java
View File

@ -5,6 +5,7 @@ import java.util.Iterator;
import java.util.Set;
import net.i2p.I2PAppContext;
import net.i2p.time.Timestamper;
/**
* Alternate location for determining the time which takes into account an offset.
@ -13,18 +14,23 @@ import net.i2p.I2PAppContext;
* (such as an NTP synchronized clock).
*
*/
public class Clock {
public class Clock implements Timestamper.UpdateListener {
private I2PAppContext _context;
private Timestamper _timestamper;
public Clock(I2PAppContext context) {
_context = context;
_offset = 0;
_alreadyChanged = false;
_listeners = new HashSet(64);
_timestamper = new Timestamper(context, this);
}
public static Clock getInstance() {
return I2PAppContext.getGlobalContext().clock();
}
public Timestamper getTimestamper() { return _timestamper; }
/** we fetch it on demand to avoid circular dependencies (logging uses the clock) */
private Log getLog() { return _context.logManager().getLog(Clock.class); }