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>

net/dsa/port.c

@@ -291,7 +291,10 @@ int dsa_port_vlan_add(struct dsa_port *dp,
 		.vlan = vlan,
 	};
 
-	if (br_vlan_enabled(dp->bridge_dev))
+	/* Can be called from dsa_slave_port_obj_add() or
+	 * dsa_slave_vlan_rx_add_vid()
+	 */
+	if (!dp->bridge_dev || br_vlan_enabled(dp->bridge_dev))
 		return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info);
 
 	return 0;
@@ -306,10 +309,13 @@ int dsa_port_vlan_del(struct dsa_port *dp,
 		.vlan = vlan,
 	};
 
-	if (netif_is_bridge_master(vlan->obj.orig_dev))
+	if (vlan->obj.orig_dev && netif_is_bridge_master(vlan->obj.orig_dev))
 		return -EOPNOTSUPP;
 
-	if (br_vlan_enabled(dp->bridge_dev))
+	/* Can be called from dsa_slave_port_obj_del() or
+	 * dsa_slave_vlan_rx_kill_vid()
+	 */
+	if (!dp->bridge_dev || br_vlan_enabled(dp->bridge_dev))
 		return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_DEL, &info);
 
 	return 0;

net/dsa/slave.c

@@ -983,6 +983,72 @@ static int dsa_slave_get_ts_info(struct net_device *dev,
 	return ds->ops->get_ts_info(ds, p->dp->index, ts);
 }
 
+static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
+				     u16 vid)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct switchdev_obj_port_vlan vlan = {
+		.vid_begin = vid,
+		.vid_end = vid,
+		/* This API only allows programming tagged, non-PVID VIDs */
+		.flags = 0,
+	};
+	struct bridge_vlan_info info;
+	int ret;
+
+	/* Check for a possible bridge VLAN entry now since there is no
+	 * need to emulate the switchdev prepare + commit phase.
+	 */
+	if (dp->bridge_dev) {
+		/* br_vlan_get_info() returns -EINVAL or -ENOENT if the
+		 * device, respectively the VID is not found, returning
+		 * 0 means success, which is a failure for us here.
+		 */
+		ret = br_vlan_get_info(dp->bridge_dev, vid, &info);
+		if (ret == 0)
+			return -EBUSY;
+	}
+
+	ret = dsa_port_vlan_add(dp, &vlan, NULL);
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
+
+	return ret;
+}
+
+static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
+				      u16 vid)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct switchdev_obj_port_vlan vlan = {
+		.vid_begin = vid,
+		.vid_end = vid,
+		/* This API only allows programming tagged, non-PVID VIDs */
+		.flags = 0,
+	};
+	struct bridge_vlan_info info;
+	int ret;
+
+	/* Check for a possible bridge VLAN entry now since there is no
+	 * need to emulate the switchdev prepare + commit phase.
+	 */
+	if (dp->bridge_dev) {
+		/* br_vlan_get_info() returns -EINVAL or -ENOENT if the
+		 * device, respectively the VID is not found, returning
+		 * 0 means success, which is a failure for us here.
+		 */
+		ret = br_vlan_get_info(dp->bridge_dev, vid, &info);
+		if (ret == 0)
+			return -EBUSY;
+	}
+
+	ret = dsa_port_vlan_del(dp, &vlan);
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
+
+	return ret;
+}
+
 static const struct ethtool_ops dsa_slave_ethtool_ops = {
 	.get_drvinfo		= dsa_slave_get_drvinfo,
 	.get_regs_len		= dsa_slave_get_regs_len,
@@ -1048,6 +1114,8 @@ static const struct net_device_ops dsa_slave_netdev_ops = {
 	.ndo_setup_tc		= dsa_slave_setup_tc,
 	.ndo_get_stats64	= dsa_slave_get_stats64,
 	.ndo_get_port_parent_id	= dsa_slave_get_port_parent_id,
+	.ndo_vlan_rx_add_vid	= dsa_slave_vlan_rx_add_vid,
+	.ndo_vlan_rx_kill_vid	= dsa_slave_vlan_rx_kill_vid,
 };
 
 static const struct switchdev_ops dsa_slave_switchdev_ops = {
@@ -1307,7 +1375,8 @@ int dsa_slave_create(struct dsa_port *port)
 	if (slave_dev == NULL)
 		return -ENOMEM;
 
-	slave_dev->features = master->vlan_features | NETIF_F_HW_TC;
+	slave_dev->features = master->vlan_features | NETIF_F_HW_TC |
+				NETIF_F_HW_VLAN_CTAG_FILTER;
 	slave_dev->hw_features |= NETIF_F_HW_TC;
 	slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;
 	eth_hw_addr_inherit(slave_dev, master);

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;