Move processing of PHC readings from sys_linux to hwclock, where
statistics can be collected and filtering improved.
In the PHC refclock driver accumulate the samples even if not in the
external timestamping mode to update the context which will be needed
for improved filtering.
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.
Avoid searching the hash table of sources when a packet in the client
mode is received. It cannot be a response from our source. Analogously,
avoid source lookups for transmitted packets in the server mode. This
doesn't change anything for packets in symmetric modes, which can be
requests and responses at the same time.
This slightly improves the maximum packet rate handled as a server.
Close /dev/urandom and drop cached getrandom() data after forking helper
processes to avoid them getting the same sequence of random numbers
(e.g. two NTS-KE helpers generating cookies with identical nonces).
arc4random() is assumed to be able to detect forks and reseed
automatically.
This is not strictly necessary with the current code, which does not use
the GetRandom functions before the NTS-KE helper processes are forked,
but that could change in future.
Also, call the reset function before exit to close /dev/urandom in order
to avoid valgrind reporting the file object as "still reachable".
The maximum value of the new 32-bit fields is slightly less than 16,
which can cause the NTP test #7 to pass for a server which has a zero
root delay but maximum root dispersion.
Interpret the maximum value as the maximum value of the original 32-bit
fields (~65536.0 seconds) for better compatibility with NTPv4.
Since commit fdfcabd79b ("ntp: drop support for long NTPv4 MACs"), the
parser doesn't need to check validify of MACs in NTPv4 packets to
distinguish them from extension fields. Move the parser to ntp_core to
avoid having a separate iteration looking for non-authentication
extension fields.
When the server clock was updated between saving of the RX timestamp and
updating the TX timestamp, a client using interleaved mode with the four
timestamps which minimize error in measured delay (e.g. chrony) had the
server clock adjustment included in the measured delay, which could
disrupt the sample filtering and weighting.
Add a handler to track the slew epoch and remember the last offset. Undo
the adjustment in TX timestamps which have their RX timestamp in the
previous epoch to fix the delay observed by the clients.
If an unknown clock step is detected, drop all timestamps.
Instead of keeping one pair of RX and TX timestamp for each address, add
a separate RX->TX map using an ordered circular buffer. Save the RX
timestamps as 64-bit integers and search them with a combined linear
interpolation and binary algorithm.
This enables the server to support multiple interleaved clients sharing
the same IP address (e.g. NAT) and it will allow other improvements to
be implemented later. A drawback is that a single broken client sending
interleaved requests at a high rate (without spoofing the source
address) can now prevent clients on other addresses from getting
interleaved responses.
The total number of saved timestamps does not change. It's still
determined by the clientloglimit directive. A new option may be added
later if needed. The whole buffer is allocated at once, but only on
first use to not waste memory on client-only configurations.
On some systems (e.g. Solaris/OpenIndiana) rand() and random() have
different ranges. RAND_MAX is the maximum value returned by rand(),
but random() should always have a range of 0 through 2^31-1.
This fixes multiple failures in different tests.
gnutls running in the FIPS140-2 mode does not allow MD5 to be
initialized, which breaks chronyd using MD5 to calculate reference ID
of IPv6 addresses. Specify a new hash algorithm for non-security MD5 use
and temporarily switch to the lax mode when initializing the hash
function.
Don't require timespec/timeval-double conversion tests to produce
correctly rounded results to handle x86 and other archs with wider
intermediate results.
Instead of selectively suspending logging by redirecting messages to
/dev/null, increase the default minimum log severity to FATAL. In the
debug mode, all messages are printed.
In the NTS-NTP client instance, maintain a local copy of the NTP address
instead of using a pointer to the NCR's address, which may change at
unexpected times.
Also, change the NNC_CreateInstance() to accept only the NTP port to
make it clear the initial NTP address is the same as the NTS-KE address
and to make it consistent with NNC_ChangeAddress(), which accepts only
one address.
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.
Don't accept NTPv4 packets which have a MAC longer than 24 octets to
strictly follow RFC 7822, which specifies the maximum length of a MAC
and the minimum length of the last extension field to avoid an ambiguity
in parsing of the packet.
This removes an ugly hack that was needed to accept packets that
contained one or more extension fields without a MAC, before RFC 7822
was written and NTP implementations started using truncated MACs.
The long MACs were used by chrony in versions 2.x when configured to
authenticate a server or peer with a key using a 256-bit or longer hash
(e.g. SHA256). For compatibility with chrony >= 4.0, these clients/peers
will need to have "version 3" added to the server/peer line in
chrony.conf.
When the request has an unrecognized critical record before the
NEXT_PROTOCOL and AEAD_ALGORITHM records, respond with error 0
(unrecognized critical record) instead of 1 (bad request).
When the request has multiple NEXT_PROTOCOL or AEAD_ALGORITHM records,
respond with error 1 (bad request).
For consistency and safety, change the CMC and HSH functions to accept
signed lengths and handle negative values as errors. Also, change the
input data type to void * to not require casting in the caller.
The daemon transmit timestamps are precompensated for the time it takes
to generate a MAC using a symmetric key (as measured on chronyd start)
and also an average round-trip time of the Samba signing of MS-SNTP
responses. This improves accuracy of the transmit timestamp, but it
has some issues.
The correction has a random error which is changing over time due to
variable CPU frequency, system load, migration to a different machine,
etc. If the measured delay is too large, the correction may cause the
transmit timestamp to be later than the actual transmission. Also, the
delay is measured for a packet of a minimal length with no extension
fields, and there is no support for NTS.
Drop the precompensation in favor of the interleaved mode, which now
avoids the authentication delay even when no kernel/hardware timestamps
are available.
