[openib-general] RDMA CM and loopback addresses

[Sean Hefty]

Jason Gunthorpe wrote:
> Well, this is what happens in the normal IP stack. To match normal IP
> semantics the source IP alone should never be mapped to a device, the
> full tuple should be passed through the route table to get to a
> device. This is what I was saying before, the IP is a property of the
> host, not of a device.

It will be difficult, if not impossible, to fully match IP semantics.  Before a 
connection can occur, hardware resources need to be allocated, which requires a 
specific device.  So, for the purpose of RDMA, we may need to treat an address 
as a property of a device, rather than the host.

Currently, rdma_bind_addr(id, source IP) may associate a cm_id with a specific 
hardware device, so the user can allocate QPs, CQs, etc.  Listen or connection 
requests are then restricted to that specific hardware device.  I.e. connections 
requests that come over an IB device, are restricted to that IB device.

- Sean