On Thu, 08 Sep 2016 06:31:14 -0700
Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Thu, 2016-09-08 at 11:15 +0200, Jesper Dangaard Brouer wrote:
> > On Wed, 07 Sep 2016 21:52:56 -0700
> > Eric Dumazet <eric.duma...@gmail.com> wrote:
> >
> > > From: Eric Dumazet <eduma...@google.com>
> > >
> > > In commit f02db315b8d8 ("ipv4: IP_TOS and IP_TTL can be specified as
> > > ancillary data") Francesco added IP_TOS values specified as integer.
> > >
> > > However, kernel sends to userspace (at recvmsg() time) an IP_TOS value
> > > in a single byte, when IP_RECVTOS is set on the socket.
> > >
> > > It can be very useful to reflect all ancillary options as given by the
> > > kernel in a subsequent sendmsg(), instead of aborting the sendmsg() with
> > > EINVAL after Francesco patch.
> > >
> > > So this patch extends IP_TOS ancillary to accept an u8, so that an UDP
> > > server can simply reuse same ancillary block without having to mangle
> > > it.
> > >
> > > Jesper can then augment
> > > https://github.com/netoptimizer/network-testing/blob/master/src/udp_example02.c
> > > to add TOS reflection ;)
> >
> > This is actually your old program ;-)
> > Do I need to change anything, as I'm just bouncing the packet back with
> > sendmsg() ?
>
> I guess you want to add an option and if this option is requested by the
> user, add :
>
> setsockopt(fd, SOL_IP, IP_PKTINFO, &on, sizeof(on));
> + if (tos_reflect)
> + setsockopt(fd, SOL_IP, IP_RECVTOS, &on, sizeof(on));
>
> before the loop doing the recvmsg()/sendmsg() calls.
Hi Eric,
I've implemented what you suggested:
https://github.com/netoptimizer/network-testing/commit/0758ad77a96ecb1
Now QA can use this tool to verify the kernel commit ;-)
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
