Add an experimental extension field for some features that were proposed
for NTPv5. Higher-resolution root delay and dispersion (using 28-bit
fraction) are added. A monotonic receive timestamp will allow a
frequency transfer between the server and client. The client will be
able to separate the server's time corrections from frequency
corrections by tracking the offset between the real-time and monotonic
receive timestamps.
The field has a type of 0xF323 from the new experimental range proposed
by the NTP working group. Include a magic 32-bit value in the field to
avoid interoperability issues if a different implementation choses the
same type for its own experimental field. The value will be changed on
incompatible changes to avoid issues between two different chrony
versions.
Add a new variable to the packet info structure with flags for extension
fields included in received packets and add a new parameter to
transmit_packet() to add the fields to transmitted packets.
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.
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.
Remove leap status from the NTP sample and set it independently from
the sample accumulation in order to accept a leap second sooner when
samples are filtered.
Add an option to enable NTS for an NTP source. Check for NTS-specific
extension fields and pass the packets to the NTS-NTP code in order to
enable the NTS client and server.
Rework the code to detect the authentication mode and count extension
fields in the first parsing of the packet and store this information in
the new packet info structure.
Add a structure for length and other information about received and
transmitted NTP packets to minimize the number of parameters and avoid
repeated parsing of the packet.
In order to allow deterministic parsing of NTPv4 extension fields, the
MAC must not be longer than 192 bits (RFC 7822). One way to get around
this limitation when using symmetric keys which produce longer MACs is
to truncate them to 192 bits (32-bit key ID and 160-bit hash).
Modify the code to accept NTPv4 packets with MACs truncated to 192
bits, but still allow long MACs in NTPv4 packets to not break
compatibility with older chrony clients.
The NTP_*_MAC_LENGTH macros didn't include the key ID, which caused the
NTP authentication check to ignore MACs with 512-bit hashes (SHA512,
WHIRLPOOL).
This was broken since update to NTPv4.
Set refid in server/broadcast packets to 127.127.1.255 when a time
smoothing offset is applied to the timestamps. This allows the clients
and administrators to detect that the server is not serving its best
estimate of the true time.
Allow different hash functions to be used in the NTP and cmdmon
protocols. This breaks the cmdmon protocol compatibility. Extended key
file format is used to specify the hash functions for chronyd and new
authhash command is added to chronyc. MD5 is the default and the only
function included in the chrony source code, other functions will be
available from libraries.
This is a verbatim copy of the files at that stage of the repository that was
built from the CVS import. It allows future development to see a bit of recent
history, but without carrying around the baggage going back to 1997. If that
is really required, git grafts can be used.
