[openib-general] mapping between IP address and device name

[Hal Rosenstock]

On Wed, 2005-06-22 at 23:16, Kevin Reilly wrote: 
> 
> Hal and others, thanks for your responses.
> 
> This kernel IBAT  looks like it provides the function to map an IP address
> of an network interface to the device name and port
> number.

Yes.

>   My reluctance is i don't think is accessible for the user space
> library. 
> We would need to have a kernel model to help
> us do the translation. Is there any plans to make it accessible to from
> user space?

Yes. There is a user space implementation (along with an updated kernel
implementation in the shaharf-ibat branch. 

-- Hal

> I would expect that mapped in both directions from the device name used to
> open a device to IP address will be very useful for
> many reason like debug.
> 
> Kevin J. Reilly
> STSM, HPC Architecture
> -Federation/HPS  Chief Engineer
> -HPC interconnect architect
> (office) 845-433-7976  (tieline) 8-293-7976
> 
> 
> 
>                                                                            
>              Hal Rosenstock                                                
>              <halr at voltaire.co                                             
>              m>                                                         To 
>                                        Kevin Reilly/Poughkeepsie/IBM at IBMUS 
>              06/21/2005 09:05                                           cc 
>              AM                        openib-general at openib.org           
>                                                                    Subject 
>                                        Re: [openib-general] mapping        
>                                        between IP address and device name  
>                                                                            
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> 
> 
> 
> Hi Kevin,
> 
> On Mon, 2005-06-20 at 22:23, Kevin Reilly wrote:
> > Maybe somebody could help me understand the proper way to map between an
> IP
> > address assigned to a port to the
> > "device  name" and "port number" in the gen2 architecture.  If I have an
> IP
> > address can I map it to a name that i get back
> > from ibv_get_device_name() or pass to ibv_open_device().
> >      Here  is  the  problem.  Let's  say  there  is  a  subsystem that
> used
> > heartbeating over IP interfaces to ascertain the adapters
> > and  ports  state,  up  or  down.   The  data  actively  maintained be
> this
> > heartbeating subsystem is used by a job scheduler that
> > desires  to  only schedule tasks on HCAs that are UP and have active
> ports.
> > The job scheduler does not want to launch jobs
> > on adapters that are broken, not connected to a switch or not configured.
> >       The  job  scheduler  needs a way to map an IP address into a name
> and
> > port number sitable to be passed to the job to
> > use   when   ibv_open_device()   is  called  or  to  match  the  output
> of
> > ibv_get_device_name().
> 
> With kernel IB Address Translation (IBAT), you can resolve an IP address
> (remote or local) and obtain the device and port are obtained from the
> ib_route structure.
> 
> ib_at_route_by_ip:
>  * ib_at_route_by_ip - asynchronously resolve ip route to ib route
>  * @dst_ip: destination ip
>  * @src_ip: source ip - optional
>  * @tos: ip type of service
>  * @flags: ib_at_route_flags
>  * @ib_route: out structure
>  * @async_comp: asynchronous callback structure - optional
>  *
>  * Resolve the specified dst_ip to a &struct ib_route structure.
>  * src_ip can be provided to force specific output interface.
>  * flags can be used to select resolving method; currently IB-ARP or ATS.
> and then:
>  * ib_at_paths_by_route - asynchronously resolve ib route to ib path
> records
>  * @ib_route: ib route to resolve
>  * @mpath_type: ib_at_multipathing_type
>  * @path_arr: SA path record array - out
>  * @npath: maximal number of paths to return
>  * @async_comp: asynchronous callback structure - optional
>  *
>  * Resolve the specified ib_route to a SA path record array.
>  * Number of returned paths will not exceed npath.
>  * Multipathing type may be used to obtain redundant paths for APM,
>  * other failover schemes, bandwidth aggregation or source based routing.
>  * Note that multipathing request is meaningless unless npath is greater
> than 1.
>  *
>  * Returned ib_route structure includes the recommended pkey and qos_tag
> for
>  * this route.
> 
> IBAT is not currently in the OpenIB trunk. See
> users/jlentini/linux-kernel/patches/ib_at.h or
> branches/shaharf-ibat/src/linux-kernel/infiniband/include/ib_at.h for
> more details.
> 
> -- Hal
> 
> > Kevin J. Reilly
> > STSM, HPC Architecture
> > -Federation/HPS  Chief Engineer
> > -HPC interconnect architect
> > (office) 845-433-7976  (tieline) 8-293-7976
> >
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