A new option is added to the ptp_utc_valid_handling parameter in
the sfptpd configuration file.
The override option sets a fixed UTC offset (seconds) value and sfptpd will ignore the UTC offset value sent by the upstream master clock. The option is provided as a means of protecting clocks against misbehaving PTP master clocks.
See the ptp_utc_valid_handling option in Instance-specific Configuration Options.