hwstamp_ctl -i interface [ -r rx-filter ] [ -t tx-type ] [ -v ]
hwstamp_ctl is a program used to set and get the hardware time stamping policy at the network driver level with the SIOCSHWTSTAMP ioctl(2). The tx-type and rx-filter values are hints to the driver what it is expected to do. If the requested fine-grained filtering for incoming packets is not supported, the driver may time stamp more than just the requested types of packets.
If neither tx-type nor rx-filter values are passed to the program, it will use the SIOCGHWTSTAMP ioctl(2) to non-destructively read the current hardware time stamping policy.
This program is a debugging tool. The ptp4l(8) program does not need this program to function, it will set the policy automatically as appropriate.
- -i interface
Specify the network interface of which the policy should be changed.
- -r rx-filter
Specify which types of incoming packets should be time stamped, rx-filter is an integer value.
- -t tx-type
Enable or disable hardware time stamping for outgoing packets, tx-type is an integer value.
Display a help message and list of possible values for rx-filter and tx-type.
Prints the software version and exits.