git: 04b4dcf04fc3 - main - leap-seconds: Update to leap-seconds 3960057600 obtained from IERS
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Date: Sun, 21 Jul 2024 01:56:50 UTC
The branch main has been updated by cy:
URL: https://cgit.FreeBSD.org/src/commit/?id=04b4dcf04fc345b29b78e5061768091648b8ee2a
commit 04b4dcf04fc345b29b78e5061768091648b8ee2a
Author: Cy Schubert <cy@FreeBSD.org>
AuthorDate: 2024-07-21 01:41:09 +0000
Commit: Cy Schubert <cy@FreeBSD.org>
CommitDate: 2024-07-21 01:55:41 +0000
leap-seconds: Update to leap-seconds 3960057600 obtained from IERS
IERS is the canonical source of leap-seconds. IANA, NIST and USNO obtain
their leap-second updates from IERS.
This resolves an issue for IPv6-only hosts as IERS is not accessible
via IPv6, requiring IPv6-only host to rely on some other source,
above.
From this point forward we should fetch the file from IERS, the
organization responsible for deciding when to insert leap-seconds.
PR: 279413
Obtained from: https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list
Discussed with: imp
MFC after: 1 day
---
usr.sbin/ntp/ntpd/leap-seconds | 373 +++++++++++++----------------------------
1 file changed, 119 insertions(+), 254 deletions(-)
diff --git a/usr.sbin/ntp/ntpd/leap-seconds b/usr.sbin/ntp/ntpd/leap-seconds
index c5a95aa51799..da0efc8c8566 100644
--- a/usr.sbin/ntp/ntpd/leap-seconds
+++ b/usr.sbin/ntp/ntpd/leap-seconds
@@ -1,255 +1,120 @@
+# ATOMIC TIME
+# Coordinated Universal Time (UTC) is the reference time scale derived
+# from The "Temps Atomique International" (TAI) calculated by the Bureau
+# International des Poids et Mesures (BIPM) using a worldwide network of atomic
+# clocks. UTC differs from TAI by an integer number of seconds; it is the basis
+# of all activities in the world.
#
-# In the following text, the symbol '#' introduces
-# a comment, which continues from that symbol until
-# the end of the line. A plain comment line has a
-# whitespace character following the comment indicator.
-# There are also special comment lines defined below.
-# A special comment will always have a non-whitespace
-# character in column 2.
-#
-# A blank line should be ignored.
-#
-# The following table shows the corrections that must
-# be applied to compute International Atomic Time (TAI)
-# from the Coordinated Universal Time (UTC) values that
-# are transmitted by almost all time services.
-#
-# The first column shows an epoch as a number of seconds
-# since 1 January 1900, 00:00:00 (1900.0 is also used to
-# indicate the same epoch.) Both of these time stamp formats
-# ignore the complexities of the time scales that were
-# used before the current definition of UTC at the start
-# of 1972. (See note 3 below.)
-# The second column shows the number of seconds that
-# must be added to UTC to compute TAI for any timestamp
-# at or after that epoch. The value on each line is
-# valid from the indicated initial instant until the
-# epoch given on the next one or indefinitely into the
-# future if there is no next line.
-# (The comment on each line shows the representation of
-# the corresponding initial epoch in the usual
-# day-month-year format. The epoch always begins at
-# 00:00:00 UTC on the indicated day. See Note 5 below.)
-#
-# Important notes:
-#
-# 1. Coordinated Universal Time (UTC) is often referred to
-# as Greenwich Mean Time (GMT). The GMT time scale is no
-# longer used, and the use of GMT to designate UTC is
-# discouraged.
-#
-# 2. The UTC time scale is realized by many national
-# laboratories and timing centers. Each laboratory
-# identifies its realization with its name: Thus
-# UTC(NIST), UTC(USNO), etc. The differences among
-# these different realizations are typically on the
-# order of a few nanoseconds (i.e., 0.000 000 00x s)
-# and can be ignored for many purposes. These differences
-# are tabulated in Circular T, which is published monthly
-# by the International Bureau of Weights and Measures
-# (BIPM). See www.bipm.org for more information.
-#
-# 3. The current definition of the relationship between UTC
-# and TAI dates from 1 January 1972. A number of different
-# time scales were in use before that epoch, and it can be
-# quite difficult to compute precise timestamps and time
-# intervals in those "prehistoric" days. For more information,
-# consult:
-#
-# The Explanatory Supplement to the Astronomical
-# Ephemeris.
-# or
-# Terry Quinn, "The BIPM and the Accurate Measurement
-# of Time," Proc. of the IEEE, Vol. 79, pp. 894-905,
-# July, 1991. <http://dx.doi.org/10.1109/5.84965>
-# reprinted in:
-# Christine Hackman and Donald B Sullivan (eds.)
-# Time and Frequency Measurement
-# American Association of Physics Teachers (1996)
-# <http://tf.nist.gov/general/pdf/1168.pdf>, pp. 75-86
-#
-# 4. The decision to insert a leap second into UTC is currently
-# the responsibility of the International Earth Rotation and
-# Reference Systems Service. (The name was changed from the
-# International Earth Rotation Service, but the acronym IERS
-# is still used.)
-#
-# Leap seconds are announced by the IERS in its Bulletin C.
-#
-# See www.iers.org for more details.
-#
-# Every national laboratory and timing center uses the
-# data from the BIPM and the IERS to construct UTC(lab),
-# their local realization of UTC.
-#
-# Although the definition also includes the possibility
-# of dropping seconds ("negative" leap seconds), this has
-# never been done and is unlikely to be necessary in the
-# foreseeable future.
-#
-# 5. If your system keeps time as the number of seconds since
-# some epoch (e.g., NTP timestamps), then the algorithm for
-# assigning a UTC time stamp to an event that happens during a positive
-# leap second is not well defined. The official name of that leap
-# second is 23:59:60, but there is no way of representing that time
-# in these systems.
-# Many systems of this type effectively stop the system clock for
-# one second during the leap second and use a time that is equivalent
-# to 23:59:59 UTC twice. For these systems, the corresponding TAI
-# timestamp would be obtained by advancing to the next entry in the
-# following table when the time equivalent to 23:59:59 UTC
-# is used for the second time. Thus the leap second which
-# occurred on 30 June 1972 at 23:59:59 UTC would have TAI
-# timestamps computed as follows:
-#
-# ...
-# 30 June 1972 23:59:59 (2287785599, first time): TAI= UTC + 10 seconds
-# 30 June 1972 23:59:60 (2287785599,second time): TAI= UTC + 11 seconds
-# 1 July 1972 00:00:00 (2287785600) TAI= UTC + 11 seconds
-# ...
-#
-# If your system realizes the leap second by repeating 00:00:00 UTC twice
-# (this is possible but not usual), then the advance to the next entry
-# in the table must occur the second time that a time equivalent to
-# 00:00:00 UTC is used. Thus, using the same example as above:
-#
-# ...
-# 30 June 1972 23:59:59 (2287785599): TAI= UTC + 10 seconds
-# 30 June 1972 23:59:60 (2287785600, first time): TAI= UTC + 10 seconds
-# 1 July 1972 00:00:00 (2287785600,second time): TAI= UTC + 11 seconds
-# ...
-#
-# in both cases the use of timestamps based on TAI produces a smooth
-# time scale with no discontinuity in the time interval. However,
-# although the long-term behavior of the time scale is correct in both
-# methods, the second method is technically not correct because it adds
-# the extra second to the wrong day.
-#
-# This complexity would not be needed for negative leap seconds (if they
-# are ever used). The UTC time would skip 23:59:59 and advance from
-# 23:59:58 to 00:00:00 in that case. The TAI offset would decrease by
-# 1 second at the same instant. This is a much easier situation to deal
-# with, since the difficulty of unambiguously representing the epoch
-# during the leap second does not arise.
-#
-# Some systems implement leap seconds by amortizing the leap second
-# over the last few minutes of the day. The frequency of the local
-# clock is decreased (or increased) to realize the positive (or
-# negative) leap second. This method removes the time step described
-# above. Although the long-term behavior of the time scale is correct
-# in this case, this method introduces an error during the adjustment
-# period both in time and in frequency with respect to the official
-# definition of UTC.
-#
-# Questions or comments to:
-# Judah Levine
-# Time and Frequency Division
-# NIST
-# Boulder, Colorado
-# Judah.Levine@nist.gov
-#
-# Last Update of leap second values: 8 July 2016
-#
-# The following line shows this last update date in NTP timestamp
-# format. This is the date on which the most recent change to
-# the leap second data was added to the file. This line can
-# be identified by the unique pair of characters in the first two
-# columns as shown below.
-#
-#$ 3676924800
-#
-# The NTP timestamps are in units of seconds since the NTP epoch,
-# which is 1 January 1900, 00:00:00. The Modified Julian Day number
-# corresponding to the NTP time stamp, X, can be computed as
-#
-# X/86400 + 15020
-#
-# where the first term converts seconds to days and the second
-# term adds the MJD corresponding to the time origin defined above.
-# The integer portion of the result is the integer MJD for that
-# day, and any remainder is the time of day, expressed as the
-# fraction of the day since 0 hours UTC. The conversion from day
-# fraction to seconds or to hours, minutes, and seconds may involve
-# rounding or truncation, depending on the method used in the
-# computation.
-#
-# The data in this file will be updated periodically as new leap
-# seconds are announced. In addition to being entered on the line
-# above, the update time (in NTP format) will be added to the basic
-# file name leap-seconds to form the name leap-seconds.<NTP TIME>.
-# In addition, the generic name leap-seconds.list will always point to
-# the most recent version of the file.
-#
-# This update procedure will be performed only when a new leap second
-# is announced.
-#
-# The following entry specifies the expiration date of the data
-# in this file in units of seconds since the origin at the instant
-# 1 January 1900, 00:00:00. This expiration date will be changed
-# at least twice per year whether or not a new leap second is
-# announced. These semi-annual changes will be made no later
-# than 1 June and 1 December of each year to indicate what
-# action (if any) is to be taken on 30 June and 31 December,
-# respectively. (These are the customary effective dates for new
-# leap seconds.) This expiration date will be identified by a
-# unique pair of characters in columns 1 and 2 as shown below.
-# In the unlikely event that a leap second is announced with an
-# effective date other than 30 June or 31 December, then this
-# file will be edited to include that leap second as soon as it is
-# announced or at least one month before the effective date
-# (whichever is later).
-# If an announcement by the IERS specifies that no leap second is
-# scheduled, then only the expiration date of the file will
-# be advanced to show that the information in the file is still
-# current -- the update time stamp, the data and the name of the file
-# will not change.
-#
-# Updated through IERS Bulletin C67
-# File expires on: 28 December 2024
-#
-#@ 3944332800
-#
-2272060800 10 # 1 Jan 1972
-2287785600 11 # 1 Jul 1972
-2303683200 12 # 1 Jan 1973
-2335219200 13 # 1 Jan 1974
-2366755200 14 # 1 Jan 1975
-2398291200 15 # 1 Jan 1976
-2429913600 16 # 1 Jan 1977
-2461449600 17 # 1 Jan 1978
-2492985600 18 # 1 Jan 1979
-2524521600 19 # 1 Jan 1980
-2571782400 20 # 1 Jul 1981
-2603318400 21 # 1 Jul 1982
-2634854400 22 # 1 Jul 1983
-2698012800 23 # 1 Jul 1985
-2776982400 24 # 1 Jan 1988
-2840140800 25 # 1 Jan 1990
-2871676800 26 # 1 Jan 1991
-2918937600 27 # 1 Jul 1992
-2950473600 28 # 1 Jul 1993
-2982009600 29 # 1 Jul 1994
-3029443200 30 # 1 Jan 1996
-3076704000 31 # 1 Jul 1997
-3124137600 32 # 1 Jan 1999
-3345062400 33 # 1 Jan 2006
-3439756800 34 # 1 Jan 2009
-3550089600 35 # 1 Jul 2012
-3644697600 36 # 1 Jul 2015
-3692217600 37 # 1 Jan 2017
-#
-# the following special comment contains the
-# hash value of the data in this file computed
-# use the secure hash algorithm as specified
-# by FIPS 180-1. See the files in ~/pub/sha for
-# the details of how this hash value is
-# computed. Note that the hash computation
-# ignores comments and whitespace characters
-# in data lines. It includes the NTP values
-# of both the last modification time and the
-# expiration time of the file, but not the
-# white space on those lines.
-# the hash line is also ignored in the
-# computation.
-#
-#h 199a9d45 3f630d2f e47cb9cc c2f0fa47 96932227
+#
+# ASTRONOMICAL TIME (UT1) is the time scale based on the rate of rotation of the earth.
+# It is now mainly derived from Very Long Baseline Interferometry (VLBI). The various
+# irregular fluctuations progressively detected in the rotation rate of the Earth led
+# in 1972 to the replacement of UT1 by UTC as the reference time scale.
+#
+#
+# LEAP SECOND
+# Atomic clocks are more stable than the rate of the earth's rotation since the latter
+# undergoes a full range of geophysical perturbations at various time scales: lunisolar
+# and core-mantle torques, atmospheric and oceanic effects, etc.
+# Leap seconds are needed to keep the two time scales in agreement, i.e. UT1-UTC smaller
+# than 0.9 seconds. Therefore, when necessary a "leap second" is applied to UTC.
+# Since the adoption of this system in 1972 it has been necessary to add a number of seconds to UTC,
+# firstly due to the initial choice of the value of the second (1/86400 mean solar day of
+# the year 1820) and secondly to the general slowing down of the Earth's rotation. It is
+# theoretically possible to have a negative leap second (a second removed from UTC), but so far,
+# all leap seconds have been positive (a second has been added to UTC). Based on what we know about
+# the earth's rotation, it is unlikely that we will ever have a negative leap second.
+#
+#
+# HISTORY
+# The first leap second was added on June 30, 1972. Until the year 2000, it was necessary in average to add a
+# leap second at a rate of 1 to 2 years. Since the year 2000 leap seconds are introduced with an
+# average interval of 3 to 4 years due to the acceleration of the Earth's rotation speed.
+#
+#
+# RESPONSIBILITY OF THE DECISION TO INTRODUCE A LEAP SECOND IN UTC
+# The decision to introduce a leap second in UTC is the responsibility of the Earth Orientation Center of
+# the International Earth Rotation and reference System Service (IERS). This center is located at Paris
+# Observatory. According to international agreements, leap seconds should be scheduled only for certain dates:
+# first preference is given to the end of December and June, and second preference at the end of March
+# and September. Since the introduction of leap seconds in 1972, only dates in June and December were used.
+#
+# Questions or comments to:
+# Christian Bizouard: christian.bizouard@obspm.fr
+# Earth orientation Center of the IERS
+# Paris Observatory, France
+#
+#
+#
+# COPYRIGHT STATUS OF THIS FILE
+# This file is in the public domain.
+#
+#
+# VALIDITY OF THE FILE
+# It is important to express the validity of the file. These next two dates are
+# given in units of seconds since 1900.0.
+#
+# 1) Last update of the file.
+#
+# Updated through IERS Bulletin C (https://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat)
+#
+# The following line shows the last update of this file in NTP timestamp:
+#
+#$ 3929093563
+#
+# 2) Expiration date of the file given on a semi-annual basis: last June or last December
+#
+# File expires on 28 June 2025
+#
+# Expire date in NTP timestamp:
+#
+#@ 3960057600
+#
+#
+# LIST OF LEAP SECONDS
+# NTP timestamp (X parameter) is the number of seconds since 1900.0
+#
+# MJD: The Modified Julian Day number. MJD = X/86400 + 15020
+#
+# DTAI: The difference DTAI= TAI-UTC in units of seconds
+# It is the quantity to add to UTC to get the time in TAI
+#
+# Day Month Year : epoch in clear
+#
+#NTP Time DTAI Day Month Year
+#
+2272060800 10 # 1 Jan 1972
+2287785600 11 # 1 Jul 1972
+2303683200 12 # 1 Jan 1973
+2335219200 13 # 1 Jan 1974
+2366755200 14 # 1 Jan 1975
+2398291200 15 # 1 Jan 1976
+2429913600 16 # 1 Jan 1977
+2461449600 17 # 1 Jan 1978
+2492985600 18 # 1 Jan 1979
+2524521600 19 # 1 Jan 1980
+2571782400 20 # 1 Jul 1981
+2603318400 21 # 1 Jul 1982
+2634854400 22 # 1 Jul 1983
+2698012800 23 # 1 Jul 1985
+2776982400 24 # 1 Jan 1988
+2840140800 25 # 1 Jan 1990
+2871676800 26 # 1 Jan 1991
+2918937600 27 # 1 Jul 1992
+2950473600 28 # 1 Jul 1993
+2982009600 29 # 1 Jul 1994
+3029443200 30 # 1 Jan 1996
+3076704000 31 # 1 Jul 1997
+3124137600 32 # 1 Jan 1999
+3345062400 33 # 1 Jan 2006
+3439756800 34 # 1 Jan 2009
+3550089600 35 # 1 Jul 2012
+3644697600 36 # 1 Jul 2015
+3692217600 37 # 1 Jan 2017
+#
+# A hash code has been generated to be able to verify the integrity
+# of this file. For more information about using this hash code,
+# please see the readme file in the 'source' directory :
+# https://hpiers.obspm.fr/iers/bul/bulc/ntp/sources/README
+#
+#h be738595 57b0cf1b b0218343 fb77062f 5a775e7