Subject: Re: [PATCHv10 bpf-next 2/4] xdp: extend xdp_redirect_map with broadcast support

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Mon, 26 Apr 2021 15:00:27 +0200

Hangbin Liu <[email-masked]> writes:

> On Mon, Apr 26, 2021 at 07:40:28PM +0800, Hangbin Liu wrote:
>> On Mon, Apr 26, 2021 at 11:53:50AM +0200, Jesper Dangaard Brouer wrote:
>> > Decode: perf_trace_xdp_redirect_template+0xba
>> >  ./scripts/faddr2line vmlinux perf_trace_xdp_redirect_template+0xba
>> > perf_trace_xdp_redirect_template+0xba/0x130:
>> > perf_trace_xdp_redirect_template at include/trace/events/xdp.h:89 (discriminator 13)
>> > 
>> > less -N net/core/filter.c
>> >  [...]
>> >    3993         if (unlikely(err))
>> >    3994                 goto err;
>> >    3995 
>> > -> 3996         _trace_xdp_redirect_map(dev, xdp_prog, fwd, map_type, map_id, ri->tgt_index);
>> 
>> Oh, the fwd in xdp xdp_redirect_map broadcast is NULL...
>> 
>> I will see how to fix it. Maybe assign the ingress interface to fwd?
>
> Er, sorry for the flood message. I just checked the trace point code, fwd
> in xdp trace event means to_ifindex. So we can't assign the ingress interface
> to fwd.
>
> In xdp_redirect_map broadcast case, there is no specific to_ifindex.
> So how about just ignore it... e.g.

Yeah, just leaving the ifindex as 0 when tgt is unset is fine :)

-Toke