Re: [dpdk-dev] [PATCH] net/mlx5: fix parsing all-multicast from flow item

[Nélio Laranjeiro]

On Wed, Jan 10, 2018 at 11:51:53PM -0800, Yongseok Koh wrote:
> As the dst_mac of allmulti is already masked with the mask, it has 0x01 in
> the first octet. Checking the least significant bit only can't distinguish
> it from broadcast or IPv6 multicast.
>
> Fixes: bb47fb6e6067 ("net/mlx5: fix flow type for allmulti rules")
> Cc: sta...@dpdk.org
> 
> Signed-off-by: Yongseok Koh <ys...@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index 305b2ec01..d01c8069b 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -1281,7 +1281,7 @@ mlx5_flow_create_eth(const struct rte_flow_item *item,
>               eth.val.ether_type &= eth.mask.ether_type;
>       }
>       mlx5_flow_create_copy(parser, &eth, eth_size);
> -     parser->allmulti = eth.val.dst_mac[0] & 1;
> +     parser->allmulti = eth.val.dst_mac[0] == 0x01;
>       return 0;
>  }
>  
> -- 
> 2.11.0
> 

Seems you are introducing a bug, for broadcast Mac addresses, this will
not work i.e. 0xff != 0x01 but it as the multicast bit set.  From my
understanding, Verbs flow attribute must also be modified in such
situation.

Are you sure about this change?

Thanks,

-- 
Nélio Laranjeiro
6WIND