A new version of the Onload Extensions API for timestamping has been added . This enables applications to interpret extension and standard timestamps reliably, irrespective of runtime configuration changes, by presenting the extended timestamps in a new, distinct, CMSG type. The old (v1) form of extension timestamping continues to work as before.
To enable the new form, pass standard SO_TIMESTAMPING-style SOF_TIMESTAMPING_* flags to a new SO_TIMETAMPING_OOEXT setsockopt option. Trailer timestamps can be enabled using the extended flag SOF_TIMESTAMPING_OOEXT_TRAILER. For example:
struct so_timestamping val = {
.flags = SOF_TIMESTAMPING_TX_HARDWARE
| SOF_TIMESTAMPING_RX_HARDWARE
| SOF_TIMESTAMPING_RAW_HARDWARE
| SOF_TIMESTAMPING_OOEXT_TRAILER
};
setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING_OOEXT, &val, sizeof val);Timestamps are delivered with a CMSG of type SCM_TIMESTAMPING_OOEXT. Each available
timestamp in the payload is provided in a struct scm_timestamping_ooext
where the type field has a combination of the elemental
SOF_TIMESTAMPING_* flags to indicate what it is, and the timestamp
field is the sub-nanosecond precision timestamp with sync flags of the form
struct onload_timestamp. The possible retrieved timestamp types
are:
SOF_TIMESTAMPING_RX_SOFTWARE | SOF_TIMESTAMPING_SOFTWARE
SOF_TIMESTAMPING_RX_HARDWARE | SOF_TIMESTAMPING_SYS_HARDWARE
SOF_TIMESTAMPING_RX_HARDWARE | SOF_TIMESTAMPING_RAW_HARDWARE
SOF_TIMESTAMPING_RX_HARDWARE | SOF_TIMESTAMPING_OOEXT_TRAILER
SOF_TIMESTAMPING_TX_HARDWARE | SOF_TIMESTAMPING_SYS_HARDWARE
SOF_TIMESTAMPING_TX_HARDWARE | SOF_TIMESTAMPING_RAW_HARDWARE