Ethernet NIC drivers depending unconditionally on INET

[Andrew Gallatin]

Bjoern A. Zeeb wrote:

>> As a sort of side-note, what about feature parity for INET6 for
>> existing IPV4 features like TSO?  Who is working on that?
> 
> Ok, maybe we should write down the big list now. What all can we have?
> What do we already have? What do we need? What needs to be changed?
> 
> IPv4 CSUM offloading
> ULP (TCP|UDP|SCTP) CSUM offloading v4/v6
>     We do have IFCAP_RXCSUM,IFCAP_TXCSUM but that means a
>     different CSUM_* subset for each card, right?
> 
>     We do have CSUM_IP, CSUM_TCP, CSUM_UDP, CSUM_SCTP.
>     What will that be?

I'm not sure what you mean by this.

Right now, at least on the receive side, tcp_input() for IPv6
is completely ignoring ULP csum values sent up by drivers.



> TSO v4/v6
>     We do have IFCAP_TSO4|IFCAP_TSO6
> 
>     We do have CSUM_TSO, so that should become CSUM_TSO4 and we'll
>     need to add CSUM_TSO6?

Cool! I had no idea that IFCAP_TSO6 was used, but apparently it is.
When I get a chance to work on FreeBSD, I guess I'll flip that
bit on in mxge and see if I actually get any packets with CSUM_TSO
set.

It would be helpful to have a CSUM_TSO{4,6} to reduce packet parsing.
But as yongari pointed out, its fairly silly to make drivers parse the
packets that the stack is sending them, and it would be ideal if
we could easily pull the information from somewhere.

> LRO v4/v6  (is anyone doing or planning to and can talk about it, LRO v6?)
>     We do have IFCAP_LRO.

I can do it for mxge, and then Jack can port it to his version.
I really need to look at finally making mxge use Jack's port of the mxge
LRO.

Drew