Subject: Re: [PATCH net-next] switchdev: enforce no pvid flag in vlan ranges

From: Vivien Didelot <[email-masked]>
Date: Mon, 12 Oct 2015 13:36:25 -0400

Hi guys,

On Oct. Monday 12 (42) 02:01 PM, Nikolay Aleksandrov wrote:
> From: Nikolay Aleksandrov <[email-masked]>
> 
> We shouldn't allow BRIDGE_VLAN_INFO_PVID flag in VLAN ranges.
> 
> Signed-off-by: Nikolay Aleksandrov <[email-masked]>
> ---
>  net/switchdev/switchdev.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
> index 6e4a4f9ad927..256c596de896 100644
> --- a/net/switchdev/switchdev.c
> +++ b/net/switchdev/switchdev.c
> @@ -720,6 +720,9 @@ static int switchdev_port_br_afspec(struct net_device *dev,
>  			if (vlan.vid_begin)
>  				return -EINVAL;
>  			vlan.vid_begin = vinfo->vid;
> +			/* don't allow range of pvids */
> +			if (vlan.flags & BRIDGE_VLAN_INFO_PVID)
> +				return -EINVAL;
>  		} else if (vinfo->flags & BRIDGE_VLAN_INFO_RANGE_END) {
>  			if (!vlan.vid_begin)
>  				return -EINVAL;
> -- 
> 2.4.3
> 

Yes the patch looks good, but it is a minor check though. I hope the
subject of this thread is making sense.

VLAN ranges seem to have been included for an UX purpose (so commands
look like Cisco IOS). We don't want to change any existing interface, so
we pushed that down to drivers, with the only valid reason that, maybe
one day, an hardware can be capable of programming a range on a per-port
basis.

So what happens is that we'll add some code to fix and check non-sense
(e.g. range + PVID) in switchdev, bridge, and I'm sure we are missing
other spots.

Sorry for being insistent, but this still doesn't look right to me.

It seems like we are bloating bridge, switchdev and drivers for the only
reason to maintain a kernel support for something like:

    # for i in $(seq 100 4000); do bridge vlan add vid $i dev swp0; done

Thanks,
-v