Re: [patch net-next RFC 0/4] introduce infrastructure for support of switch chip datapath

[Florian Fainelli <f.fainelli@gmail.com>]

2014-03-26 11:14 GMT-07:00 Jiri Pirko <jiri@resnulli.us>:
> Wed, Mar 26, 2014 at 06:58:32PM CET, f.fainelli@gmail.com wrote:
>>2014-03-26 10:35 GMT-07:00 Jiri Pirko <jiri@resnulli.us>:
>>> Wed, Mar 26, 2014 at 06:29:07PM CET, f.fainelli@gmail.com wrote:
>>>>2014-03-26 9:59 GMT-07:00 Jiri Pirko <jiri@resnulli.us>:
>>>>> Wed, Mar 26, 2014 at 05:54:17PM CET, roopa@cumulusnetworks.com wrote:
>>>>>>On 3/26/14, 3:54 AM, Jamal Hadi Salim wrote:
>>>>>>>On 03/26/14 01:37, Roopa Prabhu wrote:
>>>>>>>>On 3/25/14, 1:11 PM, Florian Fainelli wrote:
>>>>>>>>>2014-03-25 12:35 GMT-07:00 Neil Horman <nhorman@tuxdriver.com>:
>>>>>>>
>>>>>>>>Sorry about getting on this thread late and possibly in the middle.
>>>>>>>>Agree on the idea of keeping the ports linked to the master switch dev
>>>>>>>>(or the 'conduit' to the switch chip) via private list instead of the
>>>>>>>>master-slave relationship proposed earlier.
>>>>>>>>By private i mean the netdev->priv linkage to the master switch dev and
>>>>>>>>not really keeping the ports from being exposed to the user.
>>>>>>>>
>>>>>>>>We think its better to keep the switch ports exposed as any other netdev
>>>>>>>>on linux.
>>>>>>>>  This approach will make the switch ports look exactly like a nic port
>>>>>>>>and all tools will continue to work seamlessly. The switch port
>>>>>>>>operations could internally be forwarded to the switch netdev (sw1 in
>>>>>>>>the above case).
>>>>>>>>
>>>>>>>>example:
>>>>>>>>$ip link set dev sw1p0 up
>>>>>>>>$ethtool -S sw1p0
>>>>>>>>
>>>>>>>
>>>>>>>I like the approach. I know the above is a simple version, but i am
>>>>>>>assuming you also mean i can do things like
>>>>>>>ip route add ...
>>>>>>>bridge fdb add ... (and if you like your brctl go ahead)
>>>>>>>bonding ...
>>>>>>>
>>>>>>yes, exactly.  We support this model on our boxes today.
>>>>>>User can bond switch ports on our box in the exact same way as he/she
>>>>>>would bond two nic ports.
>>>>>>Our 'conduit to switch chip' reflects the corresponding lag
>>>>>>configuration in the switch chip.
>>>>>>Same goes for bridging, routing, acls.
>>>>>
>>>>>
>>>>> So you implement bonding netlink api? Or you hook into bonding driver
>>>>> itselt? Can you show us the code?
>>>>
>>>>Before we start talking about bonding, maybe we should make sure that
>>>>we cover some basic hardware switches uses which are to make some
>>>>ports belong to certain VLANs, tagged or untagged?
>>>>
>>>>It seems to me like this would become something like this, assuming P0
>>>>and P1 are two switch ports and 'eth0' is the CPU port, where P0 and
>>>>P1 belong to VLAN1 and CPU belongs to VLAN2:
>>>>
>>>>ip link set dev sw1p0 up
>>>>ip link set dev sw1p1 up
>>>>ip link set dev eth0 up
>>>
>>>
>>> I might be mistaken, But I think you are missing a switch port
>>> representing a connection to eth0 (eth0 being cpu conterpart of it).
>>> Or is it one of sw1p0 and sw1p1 ?
>>
>>You are right, sw1p0 and sw1p1 were meant to be, say LAN ports in my example.
>>
>>I think there is an implicit convention that sw1 represents the
>>Ethernet switch port connected to the CPU Ethernet MAC, and that it is
>>always connected, hence there is no need to create a "fake" bridge to
>>link sw1 to eth0 for instance?
>
> I think you are kind of mixing apples and oranges (or I might be I'm not
> understanding you correctly).
> This is how I see it, sticking to the names you use in the example:
>
>             (sw1) (abstract place-holder netdev)
>           --------
>          switch chip                   CPU
>    -----------------------            ------
>    sw1p0 sw1p1 sw1p2 sw1p3             eth0
>      |     |     |     |                |
>     PHY   PHY   PHY    ------someMII-----
>
> You see that eth0 is the CPU part of the "connection" and sw1p3 is the
> switch part (port representation).

Thanks for clarifying, this is indeed how it should be modelled/represented.
-- 
Florian