From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [patch net-next] ipv6: allow userspace to create address with IFLA_F_TEMPORARY flag Date: Tue, 29 Oct 2013 13:40:10 +0100 Message-ID: <20131029124010.GA15762@order.stressinduktion.org> References: <20131028.204306.2213130677400093266.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: David Miller , jiri@resnulli.us, vyasevich@gmail.com, netdev@vger.kernel.org, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, thaller@redhat.com, stephen@networkplumber.org To: David Laight Return-path: Received: from order.stressinduktion.org ([87.106.68.36]:35924 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753019Ab3J2MkL (ORCPT ); Tue, 29 Oct 2013 08:40:11 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Oct 29, 2013 at 09:37:06AM -0000, David Laight wrote: > > Note that you don't even need to put the DHCP protocol core into the > > kernel to fix the promiscuous problem. You just have to use the > > current kernel interfaces correctly. > > > > It used to be the case a very long time ago that you couldn't even > > receive broadcast UDP datagrams on a socket until an address was > > configured on it. > > > > So everyone turns on promiscuous mode and uses RAW sockets or > > AF_PACKET. > > > > Stupid? yes. > > Not only that, but the dhcp client could use a normal UDP socket > to keep the lease renewed - I suspect it has only ever needed > to use the BPF interface (I didn't think it set promiscuous) > when acquiring the initial lease. Yes, this is a very unfortunate situation. From my experience it is not that easy to get a patch merged into isc-dhcp. It seems not that invasive to switch from af_packet to an udp socket with SO_BROADCAST set. Greetings, Hannes