Re: [PATCH v5 0/2] Add config file support for l3fwd

["Medvedkin, Vladimir" <vladimir.medvedkin@intel.com>]

Hi,

On 09/02/2022 13:54, Bruce Richardson wrote:
> On Wed, Feb 09, 2022 at 12:00:40PM +0000, Ananyev, Konstantin wrote:
>>
>>
>>>>>> Or have a generic library for reading LPM entries.  L3fwd is supposed
>>>>>> to be as small as possible (it no longer is), and the real work should
>>>>>> be done by libraries to make it easier to build other applications.
>>>>>
>>>>> I never heard users ask about such thing,
>>>>> but if there is a demand for that, then I suppose it could be considered.
>>>>> CC-ing LPM/FIB maintainers to comment.
>>>>> Though I believe it should be a subject of separate patch and discussion
>>>>> (I think many questions will arise - what format should be, how to support
>>>>> different types of user-data, to make it generic enough, etc.).
>>>>
>>>> Agree, it is very application specific, so it could be really difficult
>>>> to make it generic.
>>>
>>> But several other also have LPM tables, so why not have common code for other applications.
>>>
>>> examples/l3fwd-power/main.c
>>> examples/ipsec-secgw/rt.c
>>> examples/ip_fragmentation/main.c
>>> examples/l3fwd/l3fwd_lpm.c
>>> examples/ip_reassembly/main.c
>>
>> Ah yes, that's good point.
>> All these examples (except ipsec-secgw) started as l3fwd clones,
>> so all of them have hard-coded LPM (and EM) tables too.
>> Yes it would be good thing to address that problem too,
>> and have some common code (and common routes file format) for all of them.
>> I don't know is that a good idea to introduce parse file function in LPM/FIB library
>> itself, might be better to  have something like examples/common/lpm_parse*.
> 
> I think it really depends on whether you are planning on implementing a
> general config file for the application, or whether the file(s) will only
> contain the LPM/FIB routing entries. If the plan is reading just the
> routing entries from file, then I definitely think that it might be
> something that would be generally useful inside the library itself.
> 
> If it's a more general config file with other app settings in it, then an
> examples-only parse function/file would make more sense.
> 

I vote for this code to be in examples where we can control the file 
format with LPM/FIB entries.
I don't think it's a good idea to move this API to the data plane 
library. I think it will only be used in our examples because dpdk users 
will have their own formats for routing information.

>> Anyway, this is an extra effort, and I think no-one has time for it in 22.03 timeframe.
>> My suggestion would be for 22.03 go ahead with current l3fwd patches,
>> then later we can consider to make it common and update other examples.
>> Konstantin

-- 
Regards,
Vladimir