Re: [PATCH v2 04/13] Connection Manager

On Tue, 2006-12-05 at 19:31 +0300, Evgeniy Polyakov wrote:

On Tue, Dec 05, 2006 at 10:12:42AM -0600, Steve Wise (swise@opengridcomputing.com) wrote:

quoted

Ah.  Data from an offloaded connection cannot leak into the main stack
nor vice-verse.  We can take an active RDMA connection establishment as
an example if you want:  Once the message is sent to the HW to "setup a
TCP connection from addr/port a.b to addr/port c.d", then packets on
that connection (that 4-tuple) will always be delivered to the RDMA
driver, not the native stack.  If the the packet received after the
connection is setup is -not- an MPA reply (in this example), then the
connection is aborted.  Once the connection is aborted.  So no leaking
can happen.

 
And if there were a dataflow between addr/port a.b to addr/port c.d
already, it will either terminated?

Considering the following sequence:
handlers->t3c_handlers->sched()->work_queue->work_handlers()->for
example CPL_PASS_ACCEPT_REQ->pass_accept_req() - it just parses incoming
skb and sets port/addr/route and other fields to be used as a base for rdma
connection. What if it just a usual network packet from kernelspace or 
userspace with the same payload as should be sent by remote rdma system?

That skb isn't a network packet.  Its a CPL_PASS_ACCEPT_REQ message (see
struct cpl_pass_accept_req in the Ethernet driver t3_cpl.h).  If the
RDMA driver hadn't registered to listen on that addr/port, it would
never get this skb.  Once a connection is established, the MPA messages
(and any TCP payload data) is delivered to the RDMA driver in the form
of skb's containing struct cpl_rx_data.  So these skbs aren't just TCP
packets at all.  They either control messages or TCP payload. Either way
they are encapsulated in CPL message structures.

Does this make sense?