When creating 8021q uppers on bridged ports on a vlan filtering bridge, we will configure the VLAN on the ports. For the dsa driver, there is no difference between a 8021q upper on bridged port and a port vlan configured within the bridge.
For that reason, if we configure a second 8021q upper for the same VLAN on a different port of the bridge, we implicitly enable forwarding between these ports on that VLAN.
This breaks the requirement for 8021q uppers for the VLAN to be consumed, so we need to reject these configurations. Reuse dsa_user_vlan_check_for_8021q_uppers() and change its argument to just the vlan id.
Before:
$ ip link add br0 type bridge vlan_filtering 1 $ ip link set swp1 master br0 $ ip link set swp2 master br0 $ ip link add swp1.100 link GbE1 type vlan id 100 $ ip link add swp2.100 link GbE2 type vlan id 100 $
After:
$ ip link add br0 type bridge vlan_filtering 1 $ ip link set swp1 master br0 $ ip link set swp2 master br0 $ ip link add swp1.100 link GbE1 type vlan id 100 $ ip link add swp2.100 link GbE2 type vlan id 100 RTNETLINK answers: Resource busy
Signed-off-by: Jonas Gorski jonas.gorski@gmail.com --- v1 -> v2: * no changes
net/dsa/user.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/net/dsa/user.c b/net/dsa/user.c index fa1fe0f1493a..e8c6452780b0 100644 --- a/net/dsa/user.c +++ b/net/dsa/user.c @@ -653,8 +653,7 @@ static int dsa_user_port_attr_set(struct net_device *dev, const void *ctx,
/* Must be called under rcu_read_lock() */ static int -dsa_user_vlan_check_for_8021q_uppers(struct dsa_port *dp, - const struct switchdev_obj_port_vlan *vlan) +dsa_user_vlan_check_for_8021q_uppers(struct dsa_port *dp, u16 other_vid) { struct dsa_switch *ds = dp->ds; struct dsa_port *other_dp; @@ -674,7 +673,7 @@ dsa_user_vlan_check_for_8021q_uppers(struct dsa_port *dp, continue;
vid = vlan_dev_vlan_id(upper_dev); - if (vid == vlan->vid) + if (vid == other_vid) return -EBUSY; } } @@ -702,7 +701,7 @@ static int dsa_user_vlan_add(struct net_device *dev, */ if (br_vlan_enabled(dsa_port_bridge_dev_get(dp))) { rcu_read_lock(); - err = dsa_user_vlan_check_for_8021q_uppers(dp, vlan); + err = dsa_user_vlan_check_for_8021q_uppers(dp, vlan->vid); rcu_read_unlock(); if (err) { NL_SET_ERR_MSG_MOD(extack, @@ -3185,6 +3184,16 @@ dsa_user_check_8021q_upper(struct net_device *dev, return notifier_from_errno(-EBUSY); }
+ rcu_read_lock(); + err = dsa_user_vlan_check_for_8021q_uppers(dp, vid); + rcu_read_unlock(); + + if (err) { + NL_SET_ERR_MSG_MOD(extack, + "This VLAN already has an upper configured on a bridge port"); + return notifier_from_errno(err); + } + return NOTIFY_DONE; }