commit 614f60fa9d73a9e8fdff3df83381907fea7c5649
author Scott McMillan <scott.a.mcmillan@intel.com> Wed Jun 02 05:53:56 2010 -0700
committer David S. Miller <davem@davemloft.net> Wed Jun 02 05:53:56 2010 -0700
tree a1b7704393b7042242470db09d59944bca67ec51
parent 7dad171c39dc83bd267c4f98d8b02d38e0d65596

packet_mmap: expose hw packet timestamps to network packet capture utilities

This patch adds a setting, PACKET_TIMESTAMP, to specify the packet
timestamp source that is exported to capture utilities like tcpdump by
packet_mmap.

PACKET_TIMESTAMP accepts the same integer bit field as
SO_TIMESTAMPING.  However, only the SOF_TIMESTAMPING_SYS_HARDWARE and
SOF_TIMESTAMPING_RAW_HARDWARE values are currently recognized by
PACKET_TIMESTAMP.  SOF_TIMESTAMPING_SYS_HARDWARE takes precedence over
SOF_TIMESTAMPING_RAW_HARDWARE if both bits are set.

If PACKET_TIMESTAMP is not set, a software timestamp generated inside
the networking stack is used (the behavior before this setting was
added).

Signed-off-by: Scott McMillan <scott.a.mcmillan@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>