[openib-general] RDMA CM and loopback addresses
Sean Hefty
mshefty at ichips.intel.com
Thu Mar 30 10:45:29 PST 2006
Jason Gunthorpe wrote:
> If you disable all packet filtering and you have two hosts
> [10.0.0.1 and 10.0.0.2] doing the following on .2:
>
> ip route add 127.0.0.1 via 10.0.0.1 dev eth0
> telnet -b 10.0.0.2 127.0.0.1
>
> And it will connect to .1's server. Turn rp_filter back on and it will
> stop working again.
Thanks - I'll give this a try and see what happens.
>>From an admin perspective it seems to me the proper thing for CMA to
> do for outgoing would be:
> - Connections with a 0 source use the destination info to consult
> the routing table to assign the correct source address
This is the current behavior.
> - Then consult the route table with a full tuple
> <src,dst,sport,dport,tclass,etc> to determine what device to send
> out on
Is it necessary to access the routing table twice? With IB, once a source
address is obtained from the step above, it's mapped to a local IB device, and
the connection is established from that RDMA device.
> Basically I'd expect all the advanced routing features in linux,
> including policy routing, to work properly for RMDA connections.
I agree, that would be ideal.
> For incoming I'd expect:
> - Incoming connections *optimally* would include the src socket
> information so that that various policy mechanisms will work.
Source address information is provided, but to be clear, we're not using sockets.
> - Then the src/dst should run through the policy stuff to see if the
> connection request should be dropped
This is not handled. I would need to see how to enable these checks.
> - Finally a full tuple route table lookup is done to ensure that a
> outgoing route exists with the proper outgoing device. (Even if it
> isn't the shortest prefix or lowest metric route)
This is also not yet done.
Thanks for the feedback.
- Sean
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