Advanced NTP client and server
da2d33e9a8
When the server's transmit timestamp was updated with a kernel/HW timestamp, it didn't include the time smoothing offset. If the offset was larger than one second, the update failed and clients using the interleaved mode received less accurate timestamps. If the update succeeded, the clients received timestamps that were not adjusted for the time smoothing offset, which added an error of up to 0.5s/1s to their measured offset/delay. Fix the update to include the smoothing offset in the new timestamp. |
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|---|---|---|
| contrib | ||
| doc | ||
| examples | ||
| test | ||
| .gitignore | ||
| addressing.h | ||
| addrfilt.c | ||
| addrfilt.h | ||
| array.c | ||
| array.h | ||
| candm.h | ||
| client.c | ||
| clientlog.c | ||
| clientlog.h | ||
| cmdmon.c | ||
| cmdmon.h | ||
| cmdparse.c | ||
| cmdparse.h | ||
| conf.c | ||
| conf.h | ||
| configure | ||
| COPYING | ||
| getdate.h | ||
| getdate.y | ||
| hash.h | ||
| hash_intmd5.c | ||
| hash_nss.c | ||
| hash_tomcrypt.c | ||
| hwclock.c | ||
| hwclock.h | ||
| keys.c | ||
| keys.h | ||
| local.c | ||
| local.h | ||
| localp.h | ||
| logging.c | ||
| logging.h | ||
| main.c | ||
| main.h | ||
| make_release | ||
| Makefile.in | ||
| manual.c | ||
| manual.h | ||
| md5.c | ||
| md5.h | ||
| memory.c | ||
| memory.h | ||
| nameserv.c | ||
| nameserv.h | ||
| nameserv_async.c | ||
| nameserv_async.h | ||
| NEWS | ||
| ntp.h | ||
| ntp_core.c | ||
| ntp_core.h | ||
| ntp_io.c | ||
| ntp_io.h | ||
| ntp_io_linux.c | ||
| ntp_io_linux.h | ||
| ntp_signd.c | ||
| ntp_signd.h | ||
| ntp_sources.c | ||
| ntp_sources.h | ||
| pktlength.c | ||
| pktlength.h | ||
| privops.c | ||
| privops.h | ||
| README | ||
| refclock.c | ||
| refclock.h | ||
| refclock_phc.c | ||
| refclock_pps.c | ||
| refclock_shm.c | ||
| refclock_sock.c | ||
| reference.c | ||
| reference.h | ||
| regress.c | ||
| regress.h | ||
| reports.h | ||
| rtc.c | ||
| rtc.h | ||
| rtc_linux.c | ||
| rtc_linux.h | ||
| sched.c | ||
| sched.h | ||
| smooth.c | ||
| smooth.h | ||
| sources.c | ||
| sources.h | ||
| sourcestats.c | ||
| sourcestats.h | ||
| srcparams.h | ||
| stubs.c | ||
| sys.c | ||
| sys.h | ||
| sys_generic.c | ||
| sys_generic.h | ||
| sys_linux.c | ||
| sys_linux.h | ||
| sys_macosx.c | ||
| sys_macosx.h | ||
| sys_netbsd.c | ||
| sys_netbsd.h | ||
| sys_solaris.c | ||
| sys_solaris.h | ||
| sys_timex.c | ||
| sys_timex.h | ||
| sysincl.h | ||
| tempcomp.c | ||
| tempcomp.h | ||
| util.c | ||
| util.h | ||
This is the README for chrony.
What is chrony?
===============
chrony is a versatile implementation of the Network Time Protocol (NTP).
It can synchronize the system clock with NTP servers, reference clocks
(e.g. GPS receiver), and manual input using wristwatch and keyboard.
It can also operate as an NTPv4 (RFC 5905) server and peer to provide
a time service to other computers in the network.
It is designed to perform well in a wide range of conditions, including
intermittent network connections, heavily congested networks, changing
temperatures (ordinary computer clocks are sensitive to temperature),
and systems that do not run continuosly, or run on a virtual machine.
Typical accuracy between two machines synchronised over the Internet is
within a few milliseconds; on a LAN, accuracy is typically in tens of
microseconds. With hardware timestamping, or a hardware reference clock,
sub-microsecond accuracy may be possible.
Two programs are included in chrony, chronyd is a daemon that can be
started at boot time and chronyc is a command-line interface program
which can be used to monitor chronyd's performance and to change various
operating parameters whilst it is running.
What will chrony run on?
========================
The software is known to work on Linux, FreeBSD, NetBSD, macOS and
Solaris. Closely related systems may work too. Any other system will
likely require a porting exercise. You would need to start from one
of the existing system-specific drivers and look into the quirks of
certain system calls and the kernel on your target system.
How do I set it up?
===================
The file INSTALL gives instructions. On supported systems the
compilation process should be automatic.
You will need an ANSI C compiler -- gcc is recommended.
The manual (in texinfo and text formats) describes how to set the
software up for the less straightforward cases.
What documentation is there?
============================
A manual is supplied in Texinfo format (chrony.texi) and
ready-formatted plain text (chrony.txt) in the distribution.
There is also information available on the chrony web pages, accessible
through the URL
https://chrony.tuxfamily.org/
Where are new versions announced?
=================================
There is a low volume mailing list where new versions and other
important news relating to chrony is announced. You can join this list
by sending mail with the subject "subscribe" to
chrony-announce-request@chrony.tuxfamily.org
These messages will be copied to chrony-users (see below).
How can I get support for chrony?
and where can I discuss new features, possible bugs etc?
========================================================
There are 3 mailing lists relating to chrony. chrony-announce was
mentioned above. chrony-users is a users' discussion list, e.g. for
general questions and answers about using chrony. chrony-dev is a more
technical list, e.g. for discussing how new features should be
implemented, exchange of information between developers etc. To
subscribe to either of these lists, send a message with the subject
"subscribe" to
chrony-users-request@chrony.tuxfamily.org
or
chrony-dev-request@chrony.tuxfamily.org
as applicable.
When you are reporting a bug, please send us all the information you can.
Unfortunately, chrony has proven to be one of those programs where it is very
difficult to reproduce bugs in a different environment. So we may have to
interact with you quite a lot to obtain enough extra logging and tracing to
pin-point the problem in some cases. Please be patient and plan for this!
License
=======
chrony is distributed under the GNU General Public License version 2.
Authors
=======
Richard P. Curnow <rc@rc0.org.uk>
Miroslav Lichvar <mlichvar@redhat.com>
Acknowledgements
================
In writing the chronyd program, extensive use has been made of RFC 1305
and RFC 5905, written by David Mills. The source code of the NTP reference
implementation has been used to check the details of the protocol.
The following people have provided patches and other major contributions
to the program :
Lonnie Abelbeck <lonnie@abelbeck.com>
Patch to add tab-completion to chronyc
Benny Lyne Amorsen <benny@amorsen.dk>
Patch to add minstratum option
Andrew Bishop <amb@gedanken.demon.co.uk>
Fixes for bugs in logging when in daemon mode
Fixes for compiler warnings
Robustness improvements for drift file
Improve installation (directory checking etc)
Entries in contrib directory
Improvements to 'sources' and 'sourcestats' output from chronyc
Improvements to documentation
Investigation of required dosynctodr behaviour for various Solaris
versions.
Stephan I. Boettcher <stephan@nevis1.columbia.edu>
Entries in contrib directory
Erik Bryer <ebryer@spots.ab.ca>
Entries in contrib directory
Bryan Christianson <bryan@whatroute.net>
Support for macOS
Support for privilege separation
Entries in contrib directory
Juliusz Chroboczek <jch@pps.jussieu.fr>
Fix install rule in Makefile if chronyd file is in use.
Paul Elliott <pelliott@io.com>
DNSchrony (in contrib directory), a tool for handling NTP servers
with variable IP addresses.
Mike Fleetwood <mike@rockover.demon.co.uk>
Fixes for compiler warnings
Alexander Gretencord <arutha@gmx.de>
Changes to installation directory system to make it easier for
package builders.
Andrew Griffiths <agriffit@redhat.com>
Patch to add support for seccomp filter
Walter Haidinger <walter.haidinger@gmx.at>
Providing me with login access to a Linux installation where v1.12
wouldn't compile, so I could develop the fixes for v1.13. Also, for
providing the disc space so I can keep an independent backup of the
sources.
Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
Port to NetBSD
John Hasler <john@dhh.gt.org>
Project and website at tuxfamily.org
Changes to support 64 bit machines (i.e. those where
sizeof(unsigned long) > 4)
Bug fix to initstepslew directive
Fix to remove potential buffer overrun errors.
Memory locking and real-time scheduler support
Fix fault where chronyd enters an endless loop
Tjalling Hattink <t.hattink@fugro.nl>
Fix scheduler to allow stepping clock from timeout handler
Patch to take leap second in PPS refclock from locked source
Patch to make reading of RTC for initial trim more reliable
Liam Hatton <me@liamhatton.com>
Advice on configuring for Linux on PPC
Jachym Holecek <jakym@volny.cz>
Patch to make Linux real time clock work with devfs
Håkan Johansson <f96hajo@chalmers.se>
Patch to avoid large values in sources and sourcestats output
Jim Knoble <jmknoble@pobox.com>
Fixes for compiler warnings
Antti Jrvinen <costello@iki.fi>
Advice on configuring for BSD/386
Victor Moroz <vim@prv.adlum.ru>
Patch to support Linux with HZ!=100
Kalle Olavi Niemitalo <tosi@stekt.oulu.fi>
acquisitionport support
Frank Otto <sandwichmacher@web.de>
Handling arbitrary HZ values
Denny Page <dennypage@me.com>
Advice on support for hardware timestamping
Gautier PHILIPPON <gautier.philippon@ensimag.grenoble-inp.fr>
Patch to add refresh command to chronyc
Andreas Piesk <apiesk@virbus.de>
Patch to make chronyc use the readline library if available
Timo Teras <timo.teras@iki.fi>
Patch to reply correctly on multihomed hosts
Bill Unruh <unruh@physics.ubc.ca>
Advice on statistics
Stephen Wadeley <swadeley@redhat.com>
Improvements to man pages
Wolfgang Weisselberg <weissel@netcologne.de>
Entries in contrib directory
Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
Many robustness and security improvements
Ulrich Windl <ulrich.windl@rz.uni-regensburg.de> for the
Providing me with information about the Linux 2.2 kernel
functionality compared to 2.0.
Doug Woodward <dougw@whistler.com>
Advice on configuring for Solaris 2.8 on x86
Many other people have contributed bug reports and suggestions. We are sorry
we cannot identify all of you individually.