On 03/01/2012 05:02 PM, Luiz Augusto von Dentz wrote:

Hi Javier,

On Thu, Mar 1, 2012 at 3:56 PM, Javier Martinez Canillas
[off-list ref] wrote:

quoted

quoted

Anyway, if you think multicast sockets is the way to go, then you could
setup a virtual network just to be able to use AF_INET multicast.

Thats probably doable without kernel patching.

We could use AF_INET multicast on a local machine but we need some
ordering and control flow requirements that are not guaranteed on UDP
multicast over IP. That's why we thought to add a new address family
AF_MCAST.

I don't want to sound like a broken record, but Im afraid I have to,
what about Ancillary Messages, how you are going to support passing
fd? Actually the whole virtual network sounds like a bad idea, are we
going to give ips to each and every application connected to the bus,
actually it is necessary to have one virtual network for each bus.

Contrary to someones believes I don't think AF_INET is that fast (e.g.
http://scottmoonen.com/2008/04/05/a-performance-comparison-of-af_unix-with-loopback-on-linux/)

You are right. Ancillary messages are PF_UNIX specific and also some
D-bus applications use fd passing for out-of-band communication. So,
using multicast on AF_INET will break these applications.

Regards,
Javier