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>
When switching from basic mode to interleaved mode following a response
which wasn't accumulated due to failed test A, B, C, or D, allow
timestamps of the failed sample to be reused in interleaved mode, i.e.
replacing the server's less accurate transmit timestamp with a more
accurate timestamp server can turn a failed sample into acceptable one.
Move the presend check into test A to simplify the code.
The presend option in interleaved mode uses two presend requests instead
of one to get an interleaved response from servers like chrony which
delay the first interleaved response due to an optimization saving
timestamps only for clients actually using the interleaved mode.
After commit 0ae6f2485b ("ntp: don't use first response in interleaved
mode") the first interleaved response following the two presend
responses in basic mode is dropped as the preferred set of timestamps
minimizing error in delay was already used by the second sample in
basic mode. There are only three responses in the burst and no sample is
accumulated.
Increasing the number of presend requests to three to get a fourth
sample would be wasteful. Instead, allow reusing timestamps of the
second presend sample in basic mode, which is never accumulated.
Reported-by: Aaron Thompson
Fixes: 0ae6f2485b ("ntp: don't use first response in interleaved mode")
Close all reusable sockets when the NTS-KE server helper is forked. It
is not supposed to have access to any of the server sockets, just the
socket for getting requests from the main process and the syslog socket.
Set the CLOEXEC flag on all reusable sockets in the initialization to
avoid leaking them to sendmail (mailonchange directive) in case the
chrony configuration doesn't use all sockets provided by systemd.
Before opening new IPv4/IPv6 server sockets, chronyd will check for
matching reusable sockets passed from the service manager (for example,
passed via systemd socket activation:
https://www.freedesktop.org/software/systemd/man/latest/sd_listen_fds.html)
and use those instead.
Aside from IPV6_V6ONLY (which cannot be set on already-bound sockets),
the daemon sets the same socket options on reusable sockets as it would
on sockets it opens itself.
Unit tests test the correct parsing of the LISTEN_FDS environment
variable.
Add 011-systemd system test to test socket activation for DGRAM and
STREAM sockets (both IPv4 and IPv6). The tests use the
systemd-socket-activate test tool, which has some limitations requiring
workarounds discussed in inline comments.
Initialize the unused value of network correction parsed from
own transmitted packets to avoid a use-of-uninitialized-value error
in NIO_UnwrapMessage() reported by clang.
Fixes: 6372a9f93f ("ntp: save PTP correction from NTP-over-PTP messages")
If the network correction is known for both the request and response,
and their sum is not larger that the measured peer delay, allowing the
transparent clocks to be running up to 100 ppm faster than the client's
clock, apply the corrections to the NTP offset and peer delay. Don't
correct the root delay to not change the estimated maximum error.
Provide the network correction (PTP correction + RX duration) of the
request in the new extension field if included in the request and
NTP-over-PTP is enabled.
To be able to verify PTP corrections, the client will need to know both
the correction of the request received by the server and the correction
of the response. Add a new experimental NTP extension field that the
clients will use to request the correction and servers return the
value.
Add two new fields to the NTP_Local_Timestamp structure:
- receive duration as the time it takes to receive the ethernet frame,
currently known only with HW timestamping
- network correction as a generalized PTP correction
The PTP correction is provided by transparent clocks in the correction
field of PTP messages to remove the receive, processing and queueing
delays of network switches and routers. Only one-step end-to-end unicast
transparent clocks are useful for NTP-over-PTP. Two-step transparent
clocks use follow-up messages and peer-to-peer transparent clocks don't
handle delay requests.
The RX duration will be included in the network correction to compensate
for asymmetric link speeds of the server and client as the NTP RX
timestamp corresponds to the end of the reception (in order to
compensate for the asymmetry in the normal case when no corrections
are applied).
Rename the exp1 extension field to exp_mono_root (monotonic timestamp +
root delay/dispersion) to better distinguish it from future experimental
extension fields.
Add support for AES-128-GCM-SIV in the current development code of
gnutls. There doesn't seem to be an API to get the cipher's minimum and
maximum nonce length and it doesn't check for invalid lengths. Hardcode
and check the limits in chrony for now.
When reloading a modified source from sourcedir which is ordered before
the original source (e.g. maxpoll was decreased), the new source is
added before the original one is removed. If the source is specified by
IP address, the addition fails due to the conflict with the original
source. Sources specified by hostname don't conflict. They are resolved
later (repeatedly if the resolver provides only conflicting addresses).
Split the processing of sorted source lists into two phases, so all
modified sources are removed before they are added again to avoid the
conflict.
Reported-by: Thomas Lange <thomas@corelatus.se>
FreeBSD allows switching the receive timestamp format to struct timespec by
setting the SO_TS_CLOCK socket option to SO_TS_REALTIME after enabling
SO_TIMESTAMP. If successful, the kernel then starts adding SCM_REALTIME
control messages instead of SCM_TIMESTAMP.
Avoid frequently ending in the middle of a client/server exchange with
long delays. This changed after commit 4a11399c2e ("ntp: rework
calculation of transmit timeout").
Clients sockets are closed immediately after receiving valid response.
Don't wait for the first early HW TX timestamp to enable waiting for
late timestamps. It may take a long time or never come if the HW/driver
is consistently slow. It's a chicken and egg problem.
Instead, simply check if HW timestamping is enabled on at least one
interface. Responses from NTP sources on other interfaces will always be
saved (for 1 millisecond by default).
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")
When refreshing a source, compare the newly resolved addresses with the
originally resolved address instead of the current address to avoid
unnecessary replacements when the address is changed due to the NTS-KE
server negotiation.
The getdate code (copied from gnulib before it was switched to GPLv3)
has multiple issues with signed integer overflows. Use the -fwrapv
compiler option for this object to at least make the operations defined.
Refresh NTP sources specified by hostname periodically (every 2 weeks
by default) to avoid long-running instances using a server which is no
longer intended for service, even if it is still responding correctly
and would not be replaced as unreachable, and help redistributing load
in large pools like pool.ntp.org. Only one source is refreshed at a time
to not interrupt clock updates if there are multiple selectable servers.
The refresh directive configures the interval. A value of 0 disables
the periodic refreshment.
Suggested-by: Ask Bjørn Hansen <ask@develooper.com>
