netdev - Re: [iproute2 net-next PATCH] ip: add a new parameter -Numeric

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Date:   Fri, 14 Jun 2019 15:00:45 -0400
From:   Roman Mashak <mrv@...atatu.com>
To:     David Ahern <dsahern@...il.com>
Cc:     Hangbin Liu <liuhangbin@...il.com>, netdev@...r.kernel.org,
        Stephen Hemminger <stephen@...workplumber.org>,
        Phil Sutter <phil@....cc>
Subject: Re: [iproute2 net-next PATCH] ip: add a new parameter -Numeric

David Ahern <dsahern@...il.com> writes:

> On 6/12/19 10:01 AM, Roman Mashak wrote:
>> Hangbin Liu <liuhangbin@...il.com> writes:
>> 
>>> Add a new parameter '-Numeric' to show the number of protocol, scope,
>>> dsfield, etc directly instead of converting it to human readable name.
>>> Do the same on tc and ss.
>>>
>>> This patch is based on David Ahern's previous patch.
>>>
>> 
>> [...]
>> 
>> It would be good idea to specify the numerical format, e.g. hex or dec,
>> very often hex is more conveninet representation (for example, when
>> skbmark is encoded of IP address or such).
>> 
>> Could you think of extending it '-Numeric' to have an optional argument
>> hex, and use decimal as default.
>> 
>
> I do not see how such an option could work.

'numeric' is extern object, so can be accessible from other modules. But
yes, it would require to add some wrappers around print_*int() APIs to
take into account this new parameter.

Yes, it is all-or-nothing approach, one can't have filters dumping their
integers values in hex but actions attached to the filters in decimal
(or the other way around).

> It would be best for iproute2 commands to output fields as hex
> or decimal based on what makes sense for each.

For example, m_police.c historically dumps its index value in hex,
although it's not very sensible IMHO :) Now it's risky to change the code,
because many scripts will likely break.

> That said, I do not see how this patch affects fields
> such as skbmark. Can you give an example? The patch looks fine to me.

The patch only exposes 'numeric' to tc, so yes -- it does not affect
anything. I only suggested to think of more generic approach.

On the 2nd thought: there already exists argument "-raw" for tc which
currently instructs printing handles in hex representation. Why not to
adopt this for ip and ss as well rather then adding new key?