Re: [PATCH] don't try to track broadcasts or multicasts (4/4)

[Martin Josefsson <gandalf@wlug.westbo.se>]

On Sat, 2002-06-08 at 09:35, Harald Welte wrote:

> hm.  I would generally agree with you, but there is one issue which
> needs to be looked into before considering this patch:
> 
> What happens if some client sends an ip-unicast diagram as link layer
> broadcast?  How does the linux stack react to this?
> 
> If the packet is processed/routed the same way like any other ip-unicast
> link-layer unicast packet, we still need to do tracking of broadcast
> packets.
> 
> Could you try to look into that and keep us posted?

Hmm why didn't I think about that?

I've done some simple testing and the results are:

TCP:
send SYN to ll broadcast: ignored
send SYN,ACK to ll broadcast: ignored

UDP:
packet sent to ll broadcast: accepted

ICMP:
echo-request sent to ll broadcast: accepted
echo-reply sent to ll broadcast: accepted
port unreachable sent to ll broadcast: accepted

I havn't done any tests with multicast ll addresses.

Seeing these results there's not much need for a patch of this kind.
TCP ll broadcasts are extremely rare. almost all ll broadcasts here are
UDP.

It was a nice thought but doesn't work in the real world.

-- 
/Martin

Never argue with an idiot. They drag you down to their level, then beat
you with experience.