[openib-general] IPoIB IETF WG presentation updated again

[Roland Dreier]

    Dror> I think that ideally, if a network device can replace the
    Dror> ARP functionality in the kernel that'll be better. Because
    Dror> this way the IPoIB can get an address resolution request
    Dror> from the IP stack, handle it by sending an ARP, then SA
    Dror> query for the path record, then creation of HCA address
    Dror> handle, and then place it in cache and pass back this
    Dror> address handle. When cache is replaced or expires, IPoIB
    Dror> will destroy the HCA address handle.  If this is not
    Dror> supported, then IPoIB will still need to maintain a shadow
    Dror> table.

I don't think the networking maintainers will have much desire to see
pluggable ARP implementations.  However it may be possible to use the
hard_header_cache() methods to handle the address vector stuff (I
haven't figured out if this can be made to work, this is just a vague
idea right now).

    Dror> Beyond that, it'll be nice if we could have gotten the IP
    Dror> datagram without the "Ethernet" header. Currently the IPoIB
    Dror> driver has to chop it, and replace it with the IPoIB
    Dror> encapsulation header. Anyway, this is just the purity of the
    Dror> protocol  stack layering.

Not sure where this is coming from -- the Linux kernel networking core
does not put an ethernet header in a packet.  The network device's
hard_header method can do whatever it wants to set up the packet.

 - Roland