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zf1s / zf1

Monorepo of a fork of Zend Framework 1, with all components split into individual composer packages. PHP 5.3-8.3 compatible.
BSD 3-Clause "New" or "Revised" License
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[zend-timesync] fix ntp time sync #153

Closed falkenhawk closed 1 year ago

falkenhawk commented 1 year ago

NTP timestamps are represented as a 64-bit fixed-point number, in seconds relative to 0000 UT on 1 January 1900. The integer part is in the first 32 bits and the fraction part in the last 32 bits.

https://www.eecis.udel.edu/~mills/time.html https://tickelton.gitlab.io/articles/ntp-timestamps/

But calculation of the fractional part was broken since forever, always sending 00000000 to a ntp server - fractional seconds were not being multiplied by max value of 32-bit+1 to represent the fraction in 0-[(2^32)-1] range, as expected by ntp protocol. In result, Zent_TimeSync_Ntp has always been reporting time in full-second resolution to ntp servers when syncing time.

Moreover, it triggered Implicit conversion from float-string "0.xyz" to int loses precision in Zend/TimeSync/Ntp.php:70 on PHP 8.1 and that's how I started my investigation.

falkenhawk commented 1 year ago

for the record, I compared the logic with java implementation TimeStamp::toNtpTime()