[En-Nut-Discussion] IP forwarding added

Ole Reinhardt ole.reinhardt at embedded-it.de
Thu Sep 20 13:25:52 CEST 2012

Hi Harald,

> Yes, in my test environment I forwarded IP packets between PPP and
> Ethernet. Actually I didn't change anything regarding multiple
> interfaces, it worked out of the box. I didn't expect any problems when
> using two (or more) Ethernet ports.

Great :)

> > We definitely will have adapt the PHY registration in a way that a PHY
> > is assigned to each Ethernet driver instance and not handled global (as
> > it currently is).
> You mean the latest changes that had been taken over from the CM3 development branch?

Exactly. Ulrichs PHY implementation allows generic PHY access and in my
eyes should be used for all ethernet chips with external phys. (AFAIK we
implemented it for all such drivers yet).

But we need to modify it a little to bind it to the ethernet driver e.g.
using an entry in the ethernet dcb and to pass the PHY device struct to
each PHY call.

Also just a little bookkeeping.

> > PS: Do you have an idea, how much effort and resources would be needed
> > to implement NAT?
> Some bookkeeping will be required. The required memory space will
> mainly depend on the number of connections that need to be handled. In
> addition, the header checksums need to be recalculated. But I think
> that even an 8-bit CPU can do this.

Sounds good! This way we can start to build our own routers :)

Best regards,



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