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