iSCSI: Urgent Pointer Negotation

[csapuntz@cisco.com]

If the URG pointer feature is to be used, it should be negotiated.

The reason it should be negotiated is that the presence of the URG
pointer takes many TCP receive stacks off of their fast path. I am
not familiar with whether it significantly slows current TCP send stacks.

Each half of the connection should be negotiated separately. This
deals with a hardware accelerator on one side and a software
implementation on the other.

Cheers,
-Costa