[PATCH net] net: bridge: mst: Check vlan state for egress decision

Elliot Ayrey
2024-07-05T03:00:51Z

If a port is blocking in the common instance but forwarding in an MST
instance, traffic egressing the bridge will be dropped because the
state of the common instance is overriding that of the MST instance.

Fix this by temporarily forcing the port state to forwarding when in
MST mode to allow checking the vlan state via br_allowed_egress().
This is similar to what happens in br_handle_frame_finish() when
checking ingress traffic, which was introduced in the change below.

Fixes: ec7328b59176 ("net: bridge: mst: Multiple Spanning Tree (MST) mode")
Signed-off-by: Elliot Ayrey <elliot.ayrey@alliedtelesis.co.nz>
---
net/bridge/br_forward.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index d97064d460dc..911b37a38a32 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -22,10 +22,16 @@ static inline int should_deliver(const struct net_bridge_port *p,
const struct sk_buff *skb)
{
struct net_bridge_vlan_group *vg;
+ u8 state;
+
+ if (br_mst_is_enabled(p->br))
+ state = BR_STATE_FORWARDING;
+ else
+ state = p->state;

vg = nbp_vlan_group_rcu(p);
return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
- p->state == BR_STATE_FORWARDING && br_allowed_egress(vg, skb) &&
+ state == BR_STATE_FORWARDING && br_allowed_egress(vg, skb) &&
nbp_switchdev_allowed_egress(p, skb) &&
!br_skb_isolated(p, skb);
}