From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Richter Subject: Re: [RFC:] struct net_device_ops: Add function pointer to fill device specific ndisc information Date: Mon, 21 Jan 2013 14:15:48 +0100 Message-ID: <20130121141548.6327224b@stein> References: <50FC2EE4.3080705@gmail.com> <50FC3BB1.4070005@linux-ipv6.org> <50FC6068.3020302@gmail.com> <20130121090951.103c0680@stein> <50FD2EBE.9050608@linux-ipv6.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev , linux1394-devel@lists.sourceforge.net, David Miller To: YOSHIFUJI Hideaki Return-path: Received: from einhorn.in-berlin.de ([192.109.42.8]:54371 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753039Ab3AUNQG (ORCPT ); Mon, 21 Jan 2013 08:16:06 -0500 In-Reply-To: <50FD2EBE.9050608@linux-ipv6.org> Sender: netdev-owner@vger.kernel.org List-ID: On Jan 21 YOSHIFUJI Hideaki wrote: > Stefan Richter wrote: > > On Jan 20 Stephan Gatzka wrote: > >> On 01/20/2013 07:47 PM, YOSHIFUJI Hideaki wrote: > >> > >>> My current position is to change "mac address" to > >>> > >>> struct fwnet_hwaddr { > >>> u8 guid[8]; > >>> u8 max_rec; > >>> u8 sspd; > >>> u8 fifo[6]; > >>> }; > >>> > >> > >> That is something I'm not really convinced of. As Stefan Richter pointed > >> out clearly, the fifo address might be different between IPv4 and IPv6 > >> communication. > > > > If it is of any help, the initial implementation could assume that IPv4 > > unicast_FIFO and IPv6 unicast_FIFO are the same. RFC 3146 is silent on > > this topic (which means it can be one way or the other), but from an > > implementation point of view, using one FIFO offset for both seems quite > > natural. Currently the only existing RFC 3146 implementation which is > > known to us is Mac OS X, and since your tests with OS X 10.6 went well, > > they obviously use one offset for both protocols. > > > > But if we actually put this assumption into the implementation now, we > > should make sure that we can easily expand the implementation later in the > > event that a third implementation comes across which uses separate > > unicast_FIFOs. > > Well, FIFO for which side? Our Linux implementation should expose a single unicast_FIFO for reception of both protocols, just in case that another implementation expects just this. For transmission, we should be ready to keep an IP-peer-to-1394-node mapping with per-protocol unicast_FIFOs, but in my mind it is doubtful that any such implementation exists (hence we could just stand prepared to implement it later when proven to be needed -- if this simplifies the initial implementation notably). > I do believe sender will not (or say, must not) care if they use > different FIFO for both protocol or not. > > Assume that peer has FIFO per protocol, one for IPv4 and another for > IPv6. ARP advertise FIFO for IPv4 and NDP advertise FIFO for IPv6. > neighbour subsystem has protocol dependent tables, and two different > NCEs (neighbour cache entries) will be created. So, sender will > correctly get FIFO from NCE for each protocol. OK. -- Stefan Richter -=====-===-= ---= =-=-= http://arcgraph.de/sr/