From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH net-next] ipv4: accept u8 in IP_TOS ancillary data Date: Tue, 13 Sep 2016 09:07:32 +0200 Message-ID: <20160913090732.069417a2@redhat.com> References: <1473310376.15733.26.camel@edumazet-glaptop3.roam.corp.google.com> <20160908111519.62af94bf@redhat.com> <1473341474.15733.36.camel@edumazet-glaptop3.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: David Miller , netdev , Francesco Fusco , Maciej =?UTF-8?B?xbtlbmN6eWtvd3NraQ==?= , brouer@redhat.com To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51334 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751547AbcIMHHh (ORCPT ); Tue, 13 Sep 2016 03:07:37 -0400 In-Reply-To: <1473341474.15733.36.camel@edumazet-glaptop3.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 08 Sep 2016 06:31:14 -0700 Eric Dumazet 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 wrote: > > > > > From: Eric Dumazet > > > > > > 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