Re: [bpf-next PATCH 3/3] samples/bpf: xdp_fwd explain bpf_fib_lookup return codes

[David Ahern <dsahern@xxxxxxxxx>]

On 8/7/19 6:36 AM, Jesper Dangaard Brouer wrote:
> Make it clear that this XDP program depend on the network
> stack to do the ARP resolution.  This is connected with the
> BPF_FIB_LKUP_RET_NO_NEIGH return code from bpf_fib_lookup().
> 
> Another common mistake (seen via XDP-tutorial) is that users
> don't realize that sysctl net.ipv{4,6}.conf.all.forwarding
> setting is honored by bpf_fib_lookup.
> 
> Reported-by: Anton Protopopov <a.s.protopopov@xxxxxxxxx>
> Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
> ---
>  samples/bpf/xdp_fwd_kern.c |   19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@xxxxxxxxx>