[ofw] udapl for windows

[Sean Hefty]

>The SendArp function sends an ARP request every time it is invoked.  It doesn't
>actually lookup the system's ARP cache.  Using SendArp was tried with WSD and
>found to give significantly worse connection establishment rates (~50%) than
>doing the ATS query to the SA, which is why WSD still uses ATS.  I suppose the
>ATS query rate depends on the SM.

Can the system's ARP cache be checked before SendArp is called?  Doesn't IPoIB
on Windows uses ARP and not ATS for its mapping?  I would prefer to have a
single mechanism for mapping IP addresses, versus trying to keep multiple
mappings in sync.

This is somewhat separate, but one of the goals of address resolution is using
the same routing tables as the IP stack in order to determine the local port (IP
address and SGID) for a connection.

- Sean