net: dsa: Add ndo_vlan_rx_{add, kill}_vid implementation

In order to properly support VLAN filtering being enabled/disabled on a
bridge, while having other ports being non bridge port members, we need
to support the ndo_vlan_rx_{add,kill}_vid callbacks in order to make
sure the non-bridge ports can continue receiving VLAN tags, even when
the switch is globally configured to do ingress/egress VID checking.

Since we can call dsa_port_vlan_{add,del} with a bridge_dev pointer
NULL, we now need to check that in these two functions.

We specifically deal with two possibly problematic cases:

- creating a bridge VLAN entry while there is an existing VLAN device
  claiming that same VID

- creating a VLAN device while there is an existing bridge VLAN entry
  with that VID

Those are both resolved with returning -EBUSY back to user-space.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 0 deletions

diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index 142b294d3446..e1fae969aa73 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -12,6 +12,7 @@
 
 #include <linux/netdevice.h>
 #include <linux/notifier.h>
+#include <linux/if_vlan.h>
 #include <net/switchdev.h>
 
 #include "dsa_priv.h"
@@ -168,6 +169,43 @@ static int dsa_switch_mdb_del(struct dsa_switch *ds,
 	return 0;
 }
 
+static int dsa_port_vlan_device_check(struct net_device *vlan_dev,
+				      int vlan_dev_vid,
+				      void *arg)
+{
+	struct switchdev_obj_port_vlan *vlan = arg;
+	u16 vid;
+
+	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
+		if (vid == vlan_dev_vid)
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
+static int dsa_port_vlan_check(struct dsa_switch *ds, int port,
+			       const struct switchdev_obj_port_vlan *vlan)
+{
+	const struct dsa_port *dp = dsa_to_port(ds, port);
+	int err = 0;
+
+	/* Device is not bridged, let it proceed with the VLAN device
+	 * creation.
+	 */
+	if (!dp->bridge_dev)
+		return err;
+
+	/* dsa_slave_vlan_rx_{add,kill}_vid() cannot use the prepare pharse and
+	 * already checks whether there is an overlapping bridge VLAN entry
+	 * with the same VID, so here we only need to check that if we are
+	 * adding a bridge VLAN entry there is not an overlapping VLAN device
+	 * claiming that VID.
+	 */
+	return vlan_for_each(dp->slave, dsa_port_vlan_device_check,
+			     (void *)vlan);
+}
+
 static int
 dsa_switch_vlan_prepare_bitmap(struct dsa_switch *ds,
 			       const struct switchdev_obj_port_vlan *vlan,
@@ -179,6 +217,10 @@ dsa_switch_vlan_prepare_bitmap(struct dsa_switch *ds,
 		return -EOPNOTSUPP;
 
 	for_each_set_bit(port, bitmap, ds->num_ports) {
+		err = dsa_port_vlan_check(ds, port, vlan);
+		if (err)
+			return err;
+
 		err = ds->ops->port_vlan_prepare(ds, port, vlan);
 		if (err)
 			return err;