Re: netdevice.7 SIOCGIFFLAGS/SIOCSIFFLAGS

[Alejandro Colomar (man-pages)]

[PING mtk, netdev@]
[CC += linux-kernel]

Hi Erik,

On 4/29/21 9:45 PM, Erik Flodin wrote:
> On Wed, 14 Apr 2021 at 21:56, Alejandro Colomar (man-pages)
> <alx.manpages@xxxxxxxxx> wrote:
>>
>> [CC += netdev]
>>
>> Hi Erik,
>>
>> On 4/14/21 8:52 PM, Erik Flodin wrote:
>>> Hi,
>>>
>>> On Fri, 19 Mar 2021 at 20:53, Alejandro Colomar (man-pages)
>>> <alx.manpages@xxxxxxxxx> wrote:
>>>> On 3/17/21 3:12 PM, Erik Flodin wrote:
>>>>> The documentation for SIOCGIFFLAGS/SIOCSIFFLAGS in netdevice.7 lists
>>>>> IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO, but those can't be set in
>>>>> ifr_flags as it is only a short and the flags start at 1<<16.
>>>>>
>>>>> See also https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=746e6ad23cd6fec2edce056e014a0eabeffa838c
>>>>>
>>>>
>>>> I don't know what's the history of that.
>>>
>>> Judging from commit message in the commit linked above it was added by
>>> mistake. As noted the flags are accessible via netlink, just not via
>>> SIOCGIFFLAGS.
>>>
>>> // Erik
>>>
>>
>> I should have CCd netdev@ before.  Thanks for the update.  Let's see if
>> anyone there can comment.
>>
>> Thanks,
>>
>> Alex
>>

> Hi again,
> 
> Have there been any updates on this one?

No, Noone from the kernel answered.  And I'm sorry, but I'm not sure
what is going on in the code, so I don't want to close this here by just
removing those flags from the manual page, because I worry that the
actual code may be wrong or something.  So I prefer that when Michael
has some time he can maybe review this and say something.  Ideally,
someone from the kernel would also respond, but they haven't.  I've CCd
the LKML; let's see if someone reads this and can help.

Thanks,

Alex

P.S.:  Please, if we haven't responded in a month from now, ping us
again.  Thanks again.

> 
> // Erik
> 
>>
>> --
>> Alejandro Colomar
>> Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
>> http://www.alejandro-colomar.es/

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/