On Jan 17, 2019, at 7:49 PM, Florian Fainelli <f.faine...@gmail.com> wrote:
> Le 1/17/19 à 6:29 PM, Guy Harris a écrit :
>> On Jan 17, 2019, at 6:01 PM, Florian Fainelli <f.faine...@gmail.com> wrote:
>>
>>> Correct. The other ports are exposed as regular Ethernet network devices.
>>
>> OK, I've updated a comment in the pull request for that.
>>
>> So, in any pre-4.19 kernels, does the directory /sys/class/net/{device}/dsa
>> exist even if there's no tagging file in that directory?
>
> Neither the directory nor the file actually exist.
>
>>
>> Or is there some other way, in pre-4.19 kernels, to determine if a NIC is a
>> DSA management-port NIC?
>>
>> If so, then, even though you can't determine the tag type from userland, you
>> could offer all the DLT_s for the various tag types in the DLT list and let
>> the user choose which one to use; they might be able to do so if they know
>> what type of device they're capturing on. (If the tagging file *does*
>> exist, you can just offer them the one DLT_ that's correct for the device.)
>>
>
> Good idea, people would certainly know which device they are capturing
> on. Thanks!
But if /sys/class/net/{device}/dsa doesn't exist in pre-4.19 kernels, how can
you determine, from userland, whether a device is a DSA management-port NIC or
not, in a system with a pre-4.19 kernel? If you can't determine that, you
can't know whether to offer a list of DSA management-port tag type DLTs or not.
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