RE: [PATCH bpf 2/4] selftests: bpf: ignore RST packets for reuseport tests

[John Fastabend]

Lorenz Bauer wrote:
> The reuseport tests currently suffer from a race condition: RST
> packets count towards DROP_ERR_SKB_DATA, since they don't contain
> a valid struct cmd. Tests will spuriously fail depending on whether
> check_results is called before or after the RST is processed.
> 
> Exit the BPF program early if FIN is set.
> 
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> ---
>  .../selftests/bpf/progs/test_select_reuseport_kern.c        | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c b/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
> index d69a1f2bbbfd..26e77dcc7e91 100644
> --- a/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
> +++ b/tools/testing/selftests/bpf/progs/test_select_reuseport_kern.c
> @@ -113,6 +113,12 @@ int _select_by_skb_data(struct sk_reuseport_md *reuse_md)
>  		data_check.skb_ports[0] = th->source;
>  		data_check.skb_ports[1] = th->dest;
>  
> +		if (th->fin)
> +			/* The connection is being torn down at the end of a
> +			 * test. It can't contain a cmd, so return early.
> +			 */
> +			return SK_PASS;
> +
>  		if ((th->doff << 2) + sizeof(*cmd) > data_check.len)
>  			GOTO_DONE(DROP_ERR_SKB_DATA);
>  		if (bpf_skb_load_bytes(reuse_md, th->doff << 2, &cmd_copy,
> -- 
> 2.20.1
> 

Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>