From: "Marcus D. Leech" <mleech@ripnet.com>
To: netdev@vger.kernel.org
Cc: patrick.ohly@gmx.de
Subject: More info on SO_TIMESTAMPING problems in V6
Date: Tue, 10 Nov 2009 14:03:19 -0500 [thread overview]
Message-ID: <4AF9B8F7.5090509@ripnet.com> (raw)
It looks like there *isn't* support on the V6 side for SO_TIMESTAMPING.
The ipv6/udp.c calls the V4 udp_sendmsg when the packet is a "V4 on a
V6 socket", but otherwise
the necessary "goop" doesn't appear to be implemented for V6.
In particular, the V4 udp_sendmsg function has a structure, ipcm_cookie,
which appears to
be used to carry the shtx flags, including the "hardware" flag that
indicates hardware
timestamping. It's not clear exactly where this gets "attached" to
the outgoing SKB, but
none of this appears in the V6 version of udp.c
While the V6 udp.c is quite *similar* to the V4 version, some of the
data structures are
quite different, and it's not clear to me where to begin. Further, I
got a note from Patrick
Ohly indicating that the e1000 driver guys at Intel have been the
ones maintaining the
SO_TIMESTAMPING code, so I don't want to replicate work that may
already be in-progress/
done.
Looking at even the latest kernel code, there's no hint that this has
been addressed.
Also, there's no hint of implementation for net/packet (AF_PACKET).
The context of all this is a PTPV2 (IEEE1588-2008) implementation that
requires hardware time-stamping support for all three of: IPV4, IPV6,
and ETHERNET (AF_PACKET/SOCK_DGRAM).
I've been testing with IPV4 exclusively, and it has been working quite well.
reply other threads:[~2009-11-10 19:05 UTC|newest]
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