[openib-general] IPoIB

[Hal Rosenstock]

On Mon, 2005-04-04 at 18:35, Grant Grundler wrote:
> On Mon, Apr 04, 2005 at 06:08:03PM -0400, Hal Rosenstock wrote:
> > A while ago, Tom brought up the issue of IPoIB link level broadcasting
> > from user space (with the arping tool). Is it possible to do this from
> > kernel space?
> 
> I would think any driver can call hard_xmit() for any "NIC".
> pktgen.c does.

Yes, but I was looking at a different "use" case. How do
net/packet/af_packet.c work when with link layer sends rather than IP
based sends ? Can this be made to work for IPoIB and how ?

> > For example, how would/could sendto() work when sending
> > to a IPoIB link layer address?
> 
> Would net/core/pktgen.c help?

Glancing at pktgen.c, there would need to be some mods made for IPoIB
as IPoIB does not deal with MAC addresses (random src/dest MACs).

pktgen.c uses the driver's transmit routine directly so this is a
different case from what I was describing.

> 	 * A tool for loading the network with preconfigurated packets.
> 	 * The tool is implemented as a linux module.  Parameters are output
> 	 * device, delay (to hard_xmit), number of packets, and whether
> 	 * to use multiple SKBs or just the same one.
> 	 * pktgen uses the installed interface's output routine.
> 
> That's one of the tools I use occasionally for performance analysis.
> This certainly would be useful to test TCP/IP <-> IB bridge/router
> support in the kernel.

Do you mean IB or IP bridge/router ? IB bridges are switches. IB routers
forward at the IB network layer and are not completely specified. I
suspect you mean an IP router with one or more IPoIB interfaces.

-- Hal