[dpdk-stable] [dpdk-dev] [PATCH] net/mlx5: prohibit wildcard match for GRE protocol

[Matan Azrad]

Hi
More info below...

From: Matan Azrad
> Hi Koh
> 
> From: Yongseok Koh
> > Currently, driver sets full mask (0xffff) for GRE protocol to device.
> > Until it is changed, PMD can't support wildcard match.
> >
> > Fixes: f4b901a46aec ("net/mlx5: add flow GRE item")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Yongseok Koh <yskoh at mellanox.com>
> > ---
> >  drivers/net/mlx5/mlx5_flow.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5_flow.c
> > b/drivers/net/mlx5/mlx5_flow.c index
> > b7500ec9d6..83ac6cbb85 100644
> > --- a/drivers/net/mlx5/mlx5_flow.c
> > +++ b/drivers/net/mlx5/mlx5_flow.c
> > @@ -1690,8 +1690,12 @@ mlx5_flow_item_gre(const struct rte_flow_item
> > *item,
> >  					  RTE_FLOW_ERROR_TYPE_ITEM,
> >  					  item,
> >  					  "L3 Layer is missing");
> > -	if (!mask)
> > -		mask = &rte_flow_item_gre_mask;
> > +	if (!mask || mask->protocol != 0xffff)
> 
> Why do you check !mask again, I think it's redundant.. no?
> 
> I think we can support also mask->protocol = 0:
> In this case we just need to not specify a spec.

Just to be more accurate:

The case of !mask led to mask->protocol = 0xffff before this patch, so it's ok and should be supported.
In addition, we can support also mask->protocol = 0 (means match all the gre protocol values) by remaining empty spec\mask to the verbs.
It can be something like this;
	if (!mask)
		mask = &rte_flow_item_gre_mask;
	if (mask->protocol == 0)
		spec = NULL;
	else if (mask->protocol != 0xffff)
		ERROR!

I checked the next flow:
eth / ipv4 / gre

It matched all the gre traffic(MLNX_OFED_LINUX-4.4-2.0.4.0).
 
> > +		return rte_flow_error_set(error, ENOTSUP,
> > +					  RTE_FLOW_ERROR_TYPE_ITEM,
> > +					  item,
> > +					  "wildcard match is not supported"
> > +					  " for protocol field of GRE");
> >  	ret = mlx5_flow_item_acceptable
> >  		(item, (const uint8_t *)mask,
> >  		 (const uint8_t *)&rte_flow_item_gre_mask,
> > --
> > 2.11.0