Aw: Re: [BUG] vlan-aware bridge breaks vlan on another port on same gmac

[Frank Wunderlich]

Hi

first thanks for the really fast and detailed answer.

> Gesendet: Freitag, 20. Januar 2023 um 18:21 Uhr
> Von: "Vladimir Oltean" <olteanv@xxxxxxxxx>
> An: "Frank Wunderlich" <frank-w@xxxxxxxxxxxxxxx>
> Cc: "Andrew Lunn" <andrew@xxxxxxx>, "Florian Fainelli" <f.fainelli@xxxxxxxxx>, "David S. Miller" <davem@xxxxxxxxxxxxx>, "Eric Dumazet" <edumazet@xxxxxxxxxx>, "Jakub Kicinski" <kuba@xxxxxxxxxx>, "Paolo Abeni" <pabeni@xxxxxxxxxx>, netdev@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, "Landen Chao" <Landen.Chao@xxxxxxxxxxxx>, "Sean Wang" <sean.wang@xxxxxxxxxxxx>, "DENG Qingfang" <dqfext@xxxxxxxxx>, "Matthias Brugger" <matthias.bgg@xxxxxxxxx>, "Daniel Golle" <daniel@xxxxxxxxxxxxxx>
> Betreff: Re: [BUG] vlan-aware bridge breaks vlan on another port on same gmac
>
> Hi Frank,
>
> On Fri, Jan 20, 2023 at 05:45:35PM +0100, Frank Wunderlich wrote:
> > Hi,
> >
> > noticed a bug while testing systemd, but it is reproducable with iproute2
> >
> > tested on bananapi-r2 with kernel 5.15.80 and bananapi-r3 with kernel 6.2-rc1,
> > both use mt7530 dsa driver but different configs (mt7530 vs. mt7531).
> > have no other devices to test.
> >
> > first create vlan on wan-port (wan and lan0 are dsa-user-ports on same gmac)
> >
> > netif=wan
> > ip link set $netif up
> > ip link add link $netif name vlan110 type vlan id 110
> > ip link set vlan110 up
> > ip addr add 192.168.110.1/24 dev vlan110
> >
> > vlan works now, other side pingable, vlan-tagged packets visible in tcpdump on both sides
>
> VLAN 110 is a software VLAN, it is never committed to hardware in the
> switch.
>
> > now create the vlan-sware bridge (without vlan_filtering it works in my test)
> >
> > BRIDGE=lanbr0
> > ip link add name ${BRIDGE} type bridge vlan_filtering 1 vlan_default_pvid 1
> > ip link set ${BRIDGE} up
> > ip link set lan0 master ${BRIDGE}
> > ip link set lan0 up
> >
> > takes some time before it is applied and ping got lost
> >
> > packets are received by other end but without vlan-tag
>
> What happens in mt7530_port_vlan_filtering() is that the user port (lan0)
> *and* the CPU port become VLAN aware. I guess it is the change on the
> CPU port that affects the traffic to "wan".

interesting, and funny to see that vlan_aware on gmac is added, but not removed in else branch :p

> But I don't see yet why this
> affects the traffic in the way you mention (the CPU port strips the tag
> instead of dropping packets with VLAN 110).

i find it strange that packets will find the way to my laptop (maybe because mac was cached from tests without the bridge and mac is same for mac and vlan there). Have not verified packets are ok, only grepped output of tcpdump for the vlan-ip as tcpdump with vlan-option does not show anything with bridge.

have posted the dumps in systemd-issue as i thought it is a systemd problem.

https://github.com/systemd/systemd/issues/25970

> I have 2 random things to suggest you try.
>
> First is this
>
> From 2991f704e6f341bd81296e91fbb4381f528f8c7f Mon Sep 17 00:00:00 2001
> From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> Date: Fri, 20 Jan 2023 19:17:16 +0200
> Subject: [PATCH] mt7530 don't make the CPU port a VLAN user port
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> ---
>  drivers/net/dsa/mt7530.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 616b21c90d05..7265c120c767 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -1524,7 +1524,7 @@ mt7530_port_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering,
>  		 * for becoming a VLAN-aware port.
>  		 */
>  		mt7530_port_set_vlan_aware(ds, port);
> -		mt7530_port_set_vlan_aware(ds, cpu_dp->index);
> +//		mt7530_port_set_vlan_aware(ds, cpu_dp->index);
>  	} else {
>  		mt7530_port_set_vlan_unaware(ds, port);
>  	}
>
> If this works, I expect it will break VLAN tagged traffic over lan0 now :)
> So I would then like you to remove the first patch and try the next one

tried first patch, and wan stays working, now i try to figure out how i can access the vlan in the bridge to set ip-address..

ip link del vlan110 #delete vlan-interface from wan to have clean routing
bridge vlan add vid 110 dev lan0
bridge vlan add vid 110 dev lanbr0 self

how can i now set ip-address to the vlan110 (imho need to extract the vlan as separate netdev) for testing that lan0 still works?

regards Frank