On Wed, Feb 8, 2017 at 2:26 AM, Miroslav Lichvar <mlich...@redhat.com> wrote: > On Tue, Feb 07, 2017 at 12:37:15PM -0800, sdncurious wrote: >> On Tue, Feb 7, 2017 at 6:01 AM, Miroslav Lichvar <mlich...@redhat.com> wrote: >> > 6) new SO_TIMESTAMPING option to get PHC index with HW timestamps >> > >> > With bridges, bonding and other things it's difficult to determine >> > which PHC timestamped the packet. It would be very useful if the >> > PHC index was provided with each HW timestamp. >> > >> > I'm not sure what would be the best place to put it. I guess the >> > second timespec in scm_timestamping could be reused for this, but >> > that sounds like a gross hack. Do we need to define a new struct? >> >> What is the use case for this. even if the delay though the PHY's how >> would that be compensated ? > > The idea was that applications like NTP servers and clients wouldn't > have to care about interfaces and how they map together with addresses > to PHCs over time. Currently, I use the interface index from > IP_PKTINFO to get the PHC, but that doesn't work with bridges and > other virtual interfaces. Another possibility would be an option to > modify the behavior of IP_PKTINFO to save the index of the real > interface. I'm not sure how would that compare in difficulty to > extending SCM_TIMESTAMPING with PHC index.
Why not just return the digest that is in the message ? Though I am not sure if the least 32 bits will result in too many collisions. RMS > > -- > Miroslav Lichvar
