On Fri, 6 Nov 2020 at 08:41, Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> By default, off xdp is implemented by actively calling netlink on the
> command line or in the program. This is very inconvenient for apps based
> on xdp. For example, an app based on xdp + xsk exits abnormally, but xdp
> is still working, which may cause some exceptions. And xsk cannot be
> automatically recycled. We need to bind xdp to the process in some
> cases, so that xdp can always be automatically released when the process exits.
>
> Although the signal can be used to handle this problem, it cannot handle
> some signals that cannot be captured. At the same time, it is
> inconvenient to use the signal to process in some cases. For example, a
> library based on xdp + xsk is not very convenient to use the signal solve
> this problem.
>
> This patch requires the app to actively call RTM_GETLINK after setting
> xdp and use RTEXT_FILTER_XDPFD flags to let the kernel generate an fd,
> and return it to the app through netlink. In this way, when the app
> closes fd or the process exits, the release callback of fd can trigger
> to off xdp.
>
Hi Xuan,
You'd like a "process scoped XDP attachment", right? I believe the
mechanism you're looking for is Andrii's bpf_link. Have look at commit
aa8d3a716b59 ("bpf, xdp: Add bpf_link-based XDP attachment API").
Cheers,
Björn
