Add minstratum and maxstratum directives to specify the minimum and
maximum allowed stratum of sources to be selected. The default values
are 0 and 15 respectively, allowing all NTP sources and refclocks.
Sources that are rejected due to having too large or too small stratum
are marked with 'r' in the selection log and selectdata report.
This is similar to the "tos floor" and "tos ceiling" settings of ntpd,
except that maxstratum is interpreted as one below the ceiling.
There is no need to save the SST_GetSelectionData() "select_ok" status
as the source is immediately marked as SRC_BAD_STATS if it is not ok.
Nothing else is using this information.
Add maxunreach option to NTP sources and refclocks to specify the
maximum number of polls that the source can stay selected for
synchronization when it is unreachable (i.e. no valid sample was
received in the last 8 polls).
It is an additional requirement to having at least one sample more
recent than the oldest sample of reachable sources.
The default value is 100000. Setting the option to 0 disables selection
of unreachable sources, which matches RFC 5905.
Include the number of unreachable sources in the "Can't synchronise: no
selectable sources" log message to provide a hint whether it might be a
networking issue.
Avoid logging the new warning messages about exceeded maxjitter or
maxdistance when only a small number of samples is collected after the
source becomes reachable and the values are unstable. Log the messages
only when a replacement attempt is made.
Some assertions are written as "if (x) assert(0)" to avoid having
the text of a long argument compiled in the binary. Rewrite them
to use a new BRIEF_ASSERT macro to make the condition easier to read in
its non-negated form and make it easier to turn it back to the full-text
assert if needed.
Add the number of sources that form an agreement (overlapping
intervals), if at least two agree with each other, and number of
reachable sources to the "Can't synchronize: no majority" log message to
better explain why synchronization is failing and hint that adding more
sources might help.
Log a warning message if a source is rejected in the source selecting
due to exceeding the maxdistance or maxjitter limit to make it more
obvious when synchronization is failing for this reason. Delay the
message until the reachability register is full (8 updates), or a
replacement of the source is attempted.
Move logging of falsetickers and system peers to the mark_source()
function. Use an array to flag already logged messages in preparation
for logging of other status. Support variable number of arguments in the
logging functions.
The commit c43efccf02 ("sources: update source selection with
unreachable sources") caused a high rate of failures in the
148-replacement test (1 falseticker vs 2 unreachable sources). This was
due to a larger fraction of the replacement attempts being made for the
source incorrectly marked as a falseticker instead of the second
unreachable source and the random process needed more time to get to the
expected state with both unreachable sources replaced.
When updating reachability of an unreachable source, try to request the
replacement of the source before calling the source selection, where
other sources may be replaced, to better balance the different
replacement attempts.
Allow one message about failed selection (e.g. no selectable sources)
to be logged before first successful selection when a source has
full-size reachability register (8 polls with a received or missed
response).
This should make it more obvious that chronyd has a wrong configuration
or there is a firewall/networking issue.
When updating the reachability register of a source with zero, call the
source selection even if the source is not the currently selected as the
best source. But do that only if all reachability bits are zero, i.e.
there was no synchronized response for last 8 polls.
This will enable the source selection to log a message when only
unreachable sources are updating reachability and it decreases the
number of unnecessary source selections.
In the source selection, check for the unsynchronized leap status after
getting sourcestats data. The unsynchronized source status is supposed
to indicate an unsynchronized source that is providing samples, not a
source which doesn't have any samples.
Also, fix the comment describing the status.
Fixes: 4c29f8888c ("sources: handle unsynchronized sources in selection")
The commit 5dd288dc0c ("sources: reselect earlier when removing
selected source") didn't cover all paths that can lead to a missing log
message when all sources are removed.
Add a flag to track the loss of selection and postpone the log message
in transient states where no message is logged to avoid spamming in
normal operation. Call SRC_SelectSource() after removing the source
to get a log message if there are no (selectable) sources left.
Reported-by: Thomas Lange <thomas@corelatus.se>
With forced reselection during source removal selected_source_index
can only be INVALID_SOURCE if there are no sources. The "Can't
synchronise: no sources" message couldn't be logged even before that as
SRC_ReselectSource() resets the index before calling SRC_SelectSource().
Replace the message with an assertion.
When a selected source is being removed, reset the instance and rerun
the selection while the source is still marked as selected. This forces
a "Can't synchronise" message to be logged when all sources are removed.
Reported-by: Thomas Lange <thomas@corelatus.se>
If noselect is present in the configured options, don't assume it
cannot change and the effective options are equal. This fixes chronyc
selectopts +noselect command.
Fixes: 3877734814 ("sources: add function to modify selection options")
Wait for four consecutive source selections giving a bad status
(falseticker, bad distance or jittery) before triggering the source
replacement. This should reduce the rate of unnecessary replacements
and shorten the time needed to find a solution when unreplaceable
falsetickers are preventing other sources from forming a majority due
to switching back and forth to unreachable servers.
Instead of waiting for the next update of reachability, trigger
replacement of falsetickers, jittery and distant sources as soon as
the selection status is updated in their SRC_SelectSource() call.
Log a warning message for each detected falseticker, but only once
between changes in the selection of the best source. Don't print all
sources when no majority is reached as that case has its own warning
message.
Add a function to add new selection options or remove existing options
specified in the configuration for both NTP sources and reference
clocks.
Provide a pair of IP address and reference ID to identify the source
depending on the type. Find the source directly in the array of sources
instead of going through the NSR hashtable for NTP sources to not
complicate it unnecessarily.
Log important changes from chronyc for auditing purposes.
Add log messages for:
- loaded symmetric keys and server NTS keys (logged also on start)
- modified maxupdateskew and makestep
- enabled/disabled local reference mode (logged also on start)
- reset time smoothing (logged also on clock steps)
- reset sources
Allow sources to accumulate samples with the leap status set to not
synchronized. Define a new state for them to be ignored in the
selection. This is intended for sources that are never synchronized and
will be used only for stabilization.
Don't print the original IP address in parentheses in the "Selected
source ..." message if it is identical to the current address. That is
expected to be the usual case for sources specified by IP address.
For reference clocks, which don't have a name, print "." instead of
NULL.
Fixes: f8610d69f0 ("sources: improve handling of dump files and their format")
After loading the dump files with the -r option, immediately perform a
source selection with forced setting of the reference. This shortens the
interval when a restarted server doesn't respond with synchronized time.
It no longer needs to wait for the first measurement from the best
source (which had to pass all the filters).
Check for write errors when saving dump files. Don't save files with no
samples. Add more sanity checks for loaded data.
Extend the file format to include an identifier, the reachability
register, leap status, name, and authentication flag. Avoid loading
unauthenticated data after switching authentication on. Change format
and order of some fields to simplify parsing. Drop fields that were kept
only for compatibility.
The dump files now contain all information needed to perform the source
selection and update the reference.
There is no support kept for the old file format. Loading of old dump
files will fail after upgrading to new version.
Remove stratum from the NTP sample and update it together with the leap
status. This enables a faster update when samples are dropped by the NTP
filters.
For sources specified by an IP address, keep the original address as the
source's name and pass it to the NCR instance. Allow the sources to go
through the replacement process if their address has changed.
This will be useful with NTS-KE negotiation.
The IP-based source names are now provided via cmdmon. This means
chronyc -n and -N can show two different addresses for a source.
Show untrusted sources with the '?' symbol instead of '-' to make them
consistent with not selectable and selectable sources in the selectdata
description.
