[openib-general] Re: IP over IB hardware address

[Michael S. Tsirkin]

Quoting r. Roland Dreier (roland at topspin.com) "Re: [openib-general] Re: [openib-commits] r894 -gen2/branches/roland-merge/src/linux-kernel/infiniband/ulp/ipoib":
>     Yaron> Having a 20 byte HW address towards the upper stack may
>     Yaron> result in some unexpected behavior with different
>     Yaron> networking tools such as sniffers, etc' , a variety of DHCP
>     Yaron> servers and few other protocols that use the hardware
>     Yaron> addresses.
> 
>     Yaron> I suggest we don't rush to incorporate the 20 byte support
>     Yaron> and think of more urgent matters, and in any case when we
>     Yaron> do get to it allow the user to configure the IPoIB to work
>     Yaron> in the 6 byte mode, to enable compatibility with those
>     Yaron> apps/protocols.
> 
> I think there's not much chance of an IPoIB driver with a "fake
> ethernet" layer being accepted in the mainline kernel.
> 
> Thanks,
>   Roland

I too think this needs to be addressed somehow.
Existing code can cause failures in IP over IB if two
guids hash to the same fake ethernet address.

So if you are not willing to go to the full 20 byte hw address
(or even if you want an option not to do it),
you have to play with SA or find some other way to perform the mapping,
properly.

MST