On Tue, May 16, 2017 at 8:44 AM, Miroslav Lichvar <mlich...@redhat.com> wrote: > Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message > for incoming packets with hardware timestamps. It contains the index of > the real interface which received the packet and the length of the > packet at layer 2. > > The index is useful with bonding, bridges and other interfaces, where > IP_PKTINFO doesn't allow applications to determine which PHC made the > timestamp. With the L2 length (and link speed) it is possible to > transpose preamble timestamps to trailer timestamps, which are used in > the NTP protocol. > > While this information could be provided by two new socket options > independently from timestamping, it doesn't look like they would be very > useful. With this option any performance impact is limited to hardware > timestamping. > > Use dev_get_by_napi_id() to get the device and its index. On kernels > with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero > index will be returned in the control message. > > CC: Richard Cochran <richardcoch...@gmail.com> > CC: Willem de Bruijn <will...@google.com> > Signed-off-by: Miroslav Lichvar <mlich...@redhat.com>
Acked-by: Willem de Bruijn <will...@google.com>
