Re: AF_XDP and packet timestamp

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

Hi Eric, 

> Hello,
> 
> I did start to work on AF_XDP support for Suricata. API was really easy
> to use via libbpf.
> 
> From Suricata point of view, the current system with default
> configuration is lacking an important information. I don't have access
> to the timestamp of the packet. I'm in particular interested by the
> hardware timestamp as it would allow to do reordering in some capture
> cases.
There's no timestamp available to my knowledge
> 
> Is there a way to get the information via AF_XDP. I've seen the
> discussion on hardware hints but there was no code example I was able
> to find. 
This is an awful hack i did when i needed similar information [1]
Essentially i am copying a software 'timestamp' (in my case rdtsc() since i
needed to measure packet timings from AF_XDP -> userspace), into the meta_data
of XDP.
The way i did it is obviously wrong since it has to be added per driver.
> 
> BR,
> -- 
> Eric Leblond <eric@regit.org>
> 

[1] https://github.com/xdp-project/xdp-project/blob/master/areas/arm64/xdp_for_tsn.org

Cheers
/Ilias