On 12/10/17 1:34 PM, Eric Leblond wrote:
>> Would it be possible to print out or preferably return to the caller
>> the ext ack error message? A couple of drivers are using it for XDP
>> mis-configuration reporting instead of printks. We should encourage
>> other to do the same and support it in all user space since ext ack
>> msgs lead to much better user experience.
>
> I've seen the kind of messages displayed by reading at kernel log. They
> are really useful and it looks almost mandatory to be able to display
> them.
>
> Kernel code seems to not have a parser for the ext ack error message.
> Did I miss something here ?
>
> Looking at tc code, it seems it is using libmnl to parse them and I
> doubt it is a good idea to use that in libbpf as it is introducing a
> dependency.
>
> Does someone has an existing parsing code or should I write on my own ?
I had worked on extack for libbpf but seem to have lost the changes.
Look at the commits here:
https://github.com/dsahern/iproute2/commits/ext-ack
I suggest using this:
https://github.com/dsahern/iproute2/commit/b61e4c7dd54a5d3ff98640da4b480441cee497b2
to bring in nlattr from lib/nlattr (as I recall lib/nlattr can not be
used directly). From there, use this one:
https://github.com/dsahern/iproute2/commit/261f7251e6704d565b91e310faabbbb7e18d14a1
to see what is needed for extack support.
Really not that much code to add.
