Merge branch 'DSA-with-VLAN-filtering-and-offloading-masters'

Vladimir Oltean says:

====================
DSA with VLAN filtering and offloading masters

This series attempts to make DSA VLANs work in the presence of a master
interface that is:
- filtering, so it drops VLANs that aren't explicitly added to its
  filter list
- offloading, so the old assumptions in the tagging code about there
  being a VLAN tag in the skb are not necessarily true anymore.

For more context:
https://lore.kernel.org/netdev/20200910150738.mwhh2i6j2qgacqev@skbuf/

This probably marks the beginning of a series of patches in which DSA
starts paying much more attention to its upper interfaces, not only for
VLAN purposes but also for address filtering and for management of the
CPU flooding domain. There was a comment from Florian on whether we
could factor some of the mlxsw logic into some common functionality, but
it doesn't look so. This seems bound to be open-coded, but frankly there
isn't a lot to it.

Changes in v2:
Applied Florian's cosmetic suggestion in patch 4/9.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 112 insertions, 44 deletions

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 66a5268398a5..2d52bfba110a 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -303,13 +303,36 @@ static int dsa_slave_port_attr_set(struct net_device *dev,
 	return ret;
 }
 
+/* Must be called under rcu_read_lock() */
+static int
+dsa_slave_vlan_check_for_8021q_uppers(struct net_device *slave,
+				      const struct switchdev_obj_port_vlan *vlan)
+{
+	struct net_device *upper_dev;
+	struct list_head *iter;
+
+	netdev_for_each_upper_dev_rcu(slave, upper_dev, iter) {
+		u16 vid;
+
+		if (!is_vlan_dev(upper_dev))
+			continue;
+
+		vid = vlan_dev_vlan_id(upper_dev);
+		if (vid >= vlan->vid_begin && vid <= vlan->vid_end)
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
 static int dsa_slave_vlan_add(struct net_device *dev,
 			      const struct switchdev_obj *obj,
 			      struct switchdev_trans *trans)
 {
+	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 	struct switchdev_obj_port_vlan vlan;
-	int err;
+	int vid, err;
 
 	if (obj->orig_dev != dev)
 		return -EOPNOTSUPP;
@@ -319,6 +342,17 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 
 	vlan = *SWITCHDEV_OBJ_PORT_VLAN(obj);
 
+	/* Deny adding a bridge VLAN when there is already an 802.1Q upper with
+	 * the same VID.
+	 */
+	if (trans->ph_prepare && br_vlan_enabled(dp->bridge_dev)) {
+		rcu_read_lock();
+		err = dsa_slave_vlan_check_for_8021q_uppers(dev, &vlan);
+		rcu_read_unlock();
+		if (err)
+			return err;
+	}
+
 	err = dsa_port_vlan_add(dp, &vlan, trans);
 	if (err)
 		return err;
@@ -333,6 +367,12 @@ static int dsa_slave_vlan_add(struct net_device *dev,
 	if (err)
 		return err;
 
+	for (vid = vlan.vid_begin; vid <= vlan.vid_end; vid++) {
+		err = vlan_vid_add(master, htons(ETH_P_8021Q), vid);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
@@ -376,7 +416,10 @@ static int dsa_slave_port_obj_add(struct net_device *dev,
 static int dsa_slave_vlan_del(struct net_device *dev,
 			      const struct switchdev_obj *obj)
 {
+	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct switchdev_obj_port_vlan *vlan;
+	int vid, err;
 
 	if (obj->orig_dev != dev)
 		return -EOPNOTSUPP;
@@ -384,10 +427,19 @@ static int dsa_slave_vlan_del(struct net_device *dev,
 	if (dsa_port_skip_vlan_configuration(dp))
 		return 0;
 
+	vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
+
 	/* Do not deprogram the CPU port as it may be shared with other user
 	 * ports which can be members of this VLAN as well.
 	 */
-	return dsa_port_vlan_del(dp, SWITCHDEV_OBJ_PORT_VLAN(obj));
+	err = dsa_port_vlan_del(dp, vlan);
+	if (err)
+		return err;
+
+	for (vid = vlan->vid_begin; vid <= vlan->vid_end; vid++)
+		vlan_vid_del(master, htons(ETH_P_8021Q), vid);
+
+	return 0;
 }
 
 static int dsa_slave_port_obj_del(struct net_device *dev,
@@ -1232,6 +1284,7 @@ static int dsa_slave_get_ts_info(struct net_device *dev,
 static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 				     u16 vid)
 {
+	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 	struct switchdev_obj_port_vlan vlan = {
 		.obj.id = SWITCHDEV_OBJ_ID_PORT_VLAN,
@@ -1240,26 +1293,9 @@ static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 		/* This API only allows programming tagged, non-PVID VIDs */
 		.flags = 0,
 	};
-	struct bridge_vlan_info info;
 	struct switchdev_trans trans;
 	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) {
-		if (dsa_port_skip_vlan_configuration(dp))
-			return 0;
-
-		/* 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;
-	}
-
 	/* User port... */
 	trans.ph_prepare = true;
 	ret = dsa_port_vlan_add(dp, &vlan, &trans);
@@ -1282,12 +1318,13 @@ static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
 	if (ret)
 		return ret;
 
-	return 0;
+	return vlan_vid_add(master, proto, vid);
 }
 
 static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
 				      u16 vid)
 {
+	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 	struct switchdev_obj_port_vlan vlan = {
 		.vid_begin = vid,
@@ -1295,29 +1332,18 @@ static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
 		/* 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) {
-		if (dsa_port_skip_vlan_configuration(dp))
-			return 0;
-
-		/* 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;
-	}
+	int err;
 
 	/* Do not deprogram the CPU port as it may be shared with other user
 	 * ports which can be members of this VLAN as well.
 	 */
-	return dsa_port_vlan_del(dp, &vlan);
+	err = dsa_port_vlan_del(dp, &vlan);
+	if (err)
+		return err;
+
+	vlan_vid_del(master, proto, vid);
+
+	return 0;
 }
 
 struct dsa_hw_port {
@@ -1895,9 +1921,9 @@ static int dsa_slave_changeupper(struct net_device *dev,
 	return err;
 }
 
-static int dsa_slave_upper_vlan_check(struct net_device *dev,
-				      struct netdev_notifier_changeupper_info *
-				      info)
+static int
+dsa_prevent_bridging_8021q_upper(struct net_device *dev,
+				 struct netdev_notifier_changeupper_info *info)
 {
 	struct netlink_ext_ack *ext_ack;
 	struct net_device *slave;
@@ -1927,14 +1953,56 @@ static int dsa_slave_upper_vlan_check(struct net_device *dev,
 	return NOTIFY_DONE;
 }
 
+static int
+dsa_slave_check_8021q_upper(struct net_device *dev,
+			    struct netdev_notifier_changeupper_info *info)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct net_device *br = dp->bridge_dev;
+	struct bridge_vlan_info br_info;
+	struct netlink_ext_ack *extack;
+	int err = NOTIFY_DONE;
+	u16 vid;
+
+	if (!br || !br_vlan_enabled(br))
+		return NOTIFY_DONE;
+
+	extack = netdev_notifier_info_to_extack(&info->info);
+	vid = vlan_dev_vlan_id(info->upper_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.
+	 */
+	err = br_vlan_get_info(br, vid, &br_info);
+	if (err == 0) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "This VLAN is already configured by the bridge");
+		return notifier_from_errno(-EBUSY);
+	}
+
+	return NOTIFY_DONE;
+}
+
 static int dsa_slave_netdevice_event(struct notifier_block *nb,
 				     unsigned long event, void *ptr)
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
-	if (event == NETDEV_CHANGEUPPER) {
+	switch (event) {
+	case NETDEV_PRECHANGEUPPER: {
+		struct netdev_notifier_changeupper_info *info = ptr;
+
+		if (!dsa_slave_dev_check(dev))
+			return dsa_prevent_bridging_8021q_upper(dev, ptr);
+
+		if (is_vlan_dev(info->upper_dev))
+			return dsa_slave_check_8021q_upper(dev, ptr);
+		break;
+	}
+	case NETDEV_CHANGEUPPER:
 		if (!dsa_slave_dev_check(dev))
-			return dsa_slave_upper_vlan_check(dev, ptr);
+			return NOTIFY_DONE;
 
 		return dsa_slave_changeupper(dev, ptr);
 	}