RFI: Ethernet driver ported from Linux

Julian Elischer julian at elischer.org
Thu Apr 19 19:34:08 UTC 2007


Alan Garfield wrote:
> On Thu, 2007-04-19 at 11:56 +0400, Yar Tikhiy wrote:
>>  
>>> Apart from using fake MAC addresses, I don't think so.
>> I don't understand the concept of a fake MAC address, sorry.
>> The classic Ethernet is a broadcast medium by design, so a very
>> primitive NIC can just receive all traffic and let the driver or
>> network stack decide if the host wants a particular frame.  On
>> output, the network stack can usually put any source MAC address
>> into the frame -- it's true for the most of Ethernet network
>> interfaces.  So MAC addresses are always "fake" in a sense, as
>> neither the hardware nor the medium design enforces them.
> 
> You're right. I don't fully understand quite what's happening behind the
> scene it would seem.

It sounds like this should be a "point-to-point" interface,
and not an Ethernet interface.. If I understand what you are saying there
is only ever communications between 2 entities.

What is on the other side of this connection?

> 
>> If I understand your case right, the two processors, CPU and SP,
>> share a hardware buffer, in which they can put some data for the
>> other side, e.g., an Ethernet frame, and then prod the other side
>> with an interrupt.  That fits the Ethernet model ideally, so there
>> should be no need for hacks unless the other side, the SP running
>> a special Linux, takes the whole thing wrong.
> 
> Again, you're correct. The Linux driver does have a certain 'quality' to
> it, but otherwise it should work as you've said.
> 
> Alan.
> 
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