Re: [PATCH RFC v1 net-next 00/12] bridge-fastpath and related improvements

[Felix Fietkau <nbd@nbd.name>]

On 16.10.24 17:59, Eric Woudstra wrote:
> 
> 
> On 10/15/24 9:44 PM, Felix Fietkau wrote:
>> On 15.10.24 15:32, Eric Woudstra wrote:
>>>
>>>
>>> On 10/15/24 2:16 PM, Felix Fietkau wrote:
>>>> Hi Eric,
>>>>
>>>> On 14.10.24 20:29, Eric Woudstra wrote:
>>>>> It would be no problem for me to change the subject and body, if you
>>>>> think that is better.
>>>>>
>>>>> The thing is, these patches actually make it possible to set up a fully
>>>>> functional software fastpath between bridged interfaces. Only after the
>>>>> software fastpath is set up and functional, it can be offloaded, which
>>>>> happens to by my personal motivation to write this patch-set.
>>>>>
>>>>> If the offload flag is set in the flowtable, the software fastpath will
>>>>> be offloaded. But in this patch-set, there is nothing that changes
>>>>> anything there, the existing code is used unchanged.
>>>>
>>>> FWIW, a while back, I also wanted to add a software fast path for the
>>>> bridge layer to the kernel, also with the intention of using it for
>>>> hardware offload. It wasn't accepted back then, because (if I remember
>>>> correctly) people didn't want any extra complexity in the network stack
>>>> to make the bridge layer faster.
>>>
>>> Hello Felix,
>>>
>>> I think this patch-set is a clear showcase it is not very complex at
>>> all. The core of making it possible only consists a few patches. Half of
>>> this patch-set involves improvements that also apply to the
>>> forward-fastpath.
>> 
>> It's definitely an interesting approach. How does it deal with devices
>> roaming from one bridge port to another? I couldn't find that in the code.
> 
> It is handled in the same manner when dealing with the forward-fastpath,
> with the aid of conntrack. If roaming is problematic, then it would be
> for both the forward-fastpath and the bridge-fastpath. I have a topic on
> the banana-pi forum about this patch-set, so I think long discussions
> about additional details we could have there, keeping the mailing list
> more clean.

You forgot to include a link to the forum topic :)

By the way, based on some reports that I received, I do believe that the 
existing forwarding fastpath also doesn't handle roaming properly.
I just didn't have the time to properly look into that yet.

- Felix