Subject: Re: [RFC:] struct net_device_ops: Add function pointer to fill device specific ndisc information

From: Stefan Richter <[email-masked]>
Date: Mon, 28 Jan 2013 00:26:33 +0100

On Jan 28 YOSHIFUJI Hideaki wrote:
> Stephan Gatzka wrote:
> 
> >> I am not a contributor to net/, hence don't have a say over how the
> >> networking APIs should evolve.
> >>
> >> Any solution is fine with me, as long as net/ does not use any definitions
> >> or declarations from <linux/firewire.h>.
> > 
> > O.k. then I will go for Yoshifujis "extended hwaddress" approch.
> > 
> > I think I will divide all the stuff into two major pieces:
> > 
> > First I will rewrite the existing IPv4 over Firewire driver to use the notification mechanisms and also generate the RFC2734 ARP packets in the arp code.
> > 
> > Then I'll implement the IPv6 stuff based on that IPv4 solution.
> 
> I even think that we do not need to have event notification if we
> can just use max_rec, sspd and fifo embedded in the destination
> "MAC address" in the sending packet.

Yes and no.  After a bus topology change, it takes a brief period for
firewire-core to have the new node(s) scanned and tell firewire-net about
them, so that firewire-net can add (or remove) items in the list for the
mapping between GUID on one hand and card:generation:nodeID on the other
hand.

So, right after a bus reset, we may already receive IP packets from nodes
which firewire-core didn't process yet.  But I guess this short period
isn't really a problem.

By the way, I wouldn't trust max_rec and sspd from 1394-ARP or 1394-NDP
packets.  These should rather be taken from firewire-core's bus analysis
as soon as this is complete.  Only unicast_FIFO can alas not be obtained
by bus analysis.  (IEEE 1394 addendum B:2002 made things more complicated
with regard to maximum payload and maximum transmission speed then they
were until addendum A:2000, in ways that the authors of RFC 2374 and 3146
surely could not anticipate.)
-- 
Stefan Richter
-=====-===-= ---= ===--
http://arcgraph.de/sr/

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