net-timestamp: extend SCM_TIMESTAMPING ancillary data struct

Applications that request kernel tx timestamps with SO_TIMESTAMPING
read timestamps as recvmsg() ancillary data. The response is defined
implicitly as timespec[3].

1) define struct scm_timestamping explicitly and

2) add support for new tstamp types. On tx, scm_timestamping always
   accompanies a sock_extended_err. Define previously unused field
   ee_info to signal the type of ts[0]. Introduce SCM_TSTAMP_SND to
   define the existing behavior.

The reception path is not modified. On rx, no struct similar to
sock_extended_err is passed along with SCM_TIMESTAMPING.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Willem de Bruijn 2014-08-04 22:11:45 -04:00 committed by David S. Miller
parent a2b81b35f9
commit f24b9be595
5 changed files with 36 additions and 10 deletions

View file

@ -22,5 +22,23 @@ struct sock_extended_err {
#define SO_EE_OFFENDER(ee) ((struct sockaddr*)((ee)+1))
/**
* struct scm_timestamping - timestamps exposed through cmsg
*
* The timestamping interfaces SO_TIMESTAMPING, MSG_TSTAMP_*
* communicate network timestamps by passing this struct in a cmsg with
* recvmsg(). See Documentation/networking/timestamping.txt for details.
*/
struct scm_timestamping {
struct timespec ts[3];
};
/* The type of scm_timestamping, passed in sock_extended_err ee_info.
* This defines the type of ts[0]. For SCM_TSTAMP_SND only, if ts[0]
* is zero, then this is a hardware timestamp and recorded in ts[2].
*/
enum {
SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */
};
#endif /* _UAPI_LINUX_ERRQUEUE_H */