> The hardware are done by the network PHY and need 1588 support in the driver, which is not common.
PTP HW timestamping is thankfully a bit more common than NTP one. From which you can deduce that it's unlikely you'll get HW timestamping in NTP context. However, new Chrony has support for encapsulating NTP in PTP to utilize the HW timestamping support for PTP. Thought I'd mention. On Wed, Dec 15, 2021 at 4:03 AM Trent Piepho <[email protected]> wrote: > On Tue, Dec 14, 2021 at 2:21 PM Hal Murray <[email protected]> wrote: > > > > > I've seen cards (ethtool) that support several time options - what > are they > > > and how do I use them? > > > > I'm not sure which options you are referring to. > > Probably the flags from ethtool -T output: > > Time stamping parameters for eth0: > Capabilities: > hardware-transmit (SOF_TIMESTAMPING_TX_HARDWARE) > software-transmit (SOF_TIMESTAMPING_TX_SOFTWARE) > hardware-receive (SOF_TIMESTAMPING_RX_HARDWARE) > software-receive (SOF_TIMESTAMPING_RX_SOFTWARE) > software-system-clock (SOF_TIMESTAMPING_SOFTWARE) > hardware-raw-clock (SOF_TIMESTAMPING_RAW_HARDWARE) > > The software ones are normally alway present and are what you describe > with the kernel's timestamping. The hardware are done by the network > PHY and need 1588 support in the driver, which is not common. I don't > think any of the RPis support it. > > > > > You can't have boxes on the internet update packets if you are > interested in > > security. > > That seems too restrictive. Consider that TLS doesn't include the > TCP/IP header, which can be modified by IP fragmentation, and that is > still considered secure. > > I think one could design a protocol such that each appended timestamp > is signed, and included a digest of all timestamps before it, so that > while one does not trust every timestamp in the chain, it can be > trusted that each timestamp was generated by entity that said it > generated it and that any timestamps generated by a trusted entity > were not later modified by a untrusted one. > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
