Merge branch 'bridge-handle-changes-in-vlan_flag_bridge_binding'

Petr Machata says:

====================
bridge: Handle changes in VLAN_FLAG_BRIDGE_BINDING

When bridge binding is enabled on a VLAN netdevice, its link state should
track bridge ports that are members of the corresponding VLAN. This works
for a newly-added netdevices. However toggling the option does not have the
effect of enabling or disabling the behavior as appropriate.

In this patchset, have bridge react to bridge_binding toggles on VLAN
uppers.

There has been another attempt at supporting this behavior in 2022 by
Sevinj Aghayeva [0]. A discussion ensued that informed how this new
patchset is constructed, namely that the logic is in the bridge as opposed
to the 8021q driver, and the bridge reacts to NETDEV_CHANGE events on the
8021q upper.

Patches #1 and #2 contain the implementation, patches #3 and #4 a
selftest.

[0] https://lore.kernel.org/netdev/cover.1660100506.git.sevinj.aghayeva@gmail.com/
====================

Link: https://patch.msgid.link/cover.1734540770.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/bridge/br.c

@@ -51,6 +51,13 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
 		}
 	}
 
+	if (is_vlan_dev(dev)) {
+		struct net_device *real_dev = vlan_dev_real_dev(dev);
+
+		if (netif_is_bridge_master(real_dev))
+			br_vlan_vlan_upper_event(real_dev, dev, event);
+	}
+
 	/* not a port of a bridge */
 	p = br_port_get_rtnl(dev);
 	if (!p)

net/bridge/br_private.h

@@ -1571,6 +1571,9 @@ void br_vlan_get_stats(const struct net_bridge_vlan *v,
 void br_vlan_port_event(struct net_bridge_port *p, unsigned long event);
 int br_vlan_bridge_event(struct net_device *dev, unsigned long event,
 			 void *ptr);
+void br_vlan_vlan_upper_event(struct net_device *br_dev,
+			      struct net_device *vlan_dev,
+			      unsigned long event);
 int br_vlan_rtnl_init(void);
 void br_vlan_rtnl_uninit(void);
 void br_vlan_notify(const struct net_bridge *br,
@@ -1802,6 +1805,12 @@ static inline int br_vlan_bridge_event(struct net_device *dev,
 	return 0;
 }
 
+static inline void br_vlan_vlan_upper_event(struct net_device *br_dev,
+					    struct net_device *vlan_dev,
+					    unsigned long event)
+{
+}
+
 static inline int br_vlan_rtnl_init(void)
 {
 	return 0;

net/bridge/br_vlan.c

@@ -1664,6 +1664,18 @@ static void br_vlan_set_all_vlan_dev_state(struct net_bridge_port *p)
 	}
 }
 
+static void br_vlan_toggle_bridge_binding(struct net_device *br_dev,
+					  bool enable)
+{
+	struct net_bridge *br = netdev_priv(br_dev);
+
+	if (enable)
+		br_opt_toggle(br, BROPT_VLAN_BRIDGE_BINDING, true);
+	else
+		br_opt_toggle(br, BROPT_VLAN_BRIDGE_BINDING,
+			      br_vlan_has_upper_bind_vlan_dev(br_dev));
+}
+
 static void br_vlan_upper_change(struct net_device *dev,
 				 struct net_device *upper_dev,
 				 bool linking)
@@ -1673,13 +1685,9 @@ static void br_vlan_upper_change(struct net_device *dev,
 	if (!br_vlan_is_bind_vlan_dev(upper_dev))
 		return;
 
-	if (linking) {
+	br_vlan_toggle_bridge_binding(dev, linking);
+	if (linking)
 		br_vlan_set_vlan_dev_state(br, upper_dev);
-		br_opt_toggle(br, BROPT_VLAN_BRIDGE_BINDING, true);
-	} else {
-		br_opt_toggle(br, BROPT_VLAN_BRIDGE_BINDING,
-			      br_vlan_has_upper_bind_vlan_dev(dev));
-	}
 }
 
 struct br_vlan_link_state_walk_data {
@@ -1764,6 +1772,30 @@ int br_vlan_bridge_event(struct net_device *dev, unsigned long event, void *ptr)
 	return ret;
 }
 
+void br_vlan_vlan_upper_event(struct net_device *br_dev,
+			      struct net_device *vlan_dev,
+			      unsigned long event)
+{
+	struct vlan_dev_priv *vlan = vlan_dev_priv(vlan_dev);
+	struct net_bridge *br = netdev_priv(br_dev);
+	bool bridge_binding;
+
+	switch (event) {
+	case NETDEV_CHANGE:
+	case NETDEV_UP:
+		break;
+	default:
+		return;
+	}
+
+	bridge_binding = vlan->flags & VLAN_FLAG_BRIDGE_BINDING;
+	br_vlan_toggle_bridge_binding(br_dev, bridge_binding);
+	if (bridge_binding)
+		br_vlan_set_vlan_dev_state(br, vlan_dev);
+	else if (!bridge_binding && netif_carrier_ok(br_dev))
+		netif_carrier_on(vlan_dev);
+}
+
 /* Must be protected by RTNL. */
 void br_vlan_port_event(struct net_bridge_port *p, unsigned long event)
 {

tools/testing/selftests/net/Makefile

@@ -96,6 +96,7 @@ TEST_PROGS += test_bridge_backup_port.sh
 TEST_PROGS += fdb_flush.sh fdb_notify.sh
 TEST_PROGS += fq_band_pktlimit.sh
 TEST_PROGS += vlan_hw_filter.sh
+TEST_PROGS += vlan_bridge_binding.sh
 TEST_PROGS += bpf_offload.py
 TEST_PROGS += ipv6_route_update_soft_lockup.sh
 TEST_PROGS += busy_poll_test.sh

tools/testing/selftests/net/lib.sh

@@ -477,12 +477,33 @@ ip_link_set_addr()
 	defer ip link set dev "$name" address "$old_addr"
 }
 
+ip_link_is_up()
+{
+	local name=$1; shift
+
+	local state=$(ip -j link show "$name" |
+		      jq -r '(.[].flags[] | select(. == "UP")) // "DOWN"')
+	[[ $state == "UP" ]]
+}
+
 ip_link_set_up()
 {
 	local name=$1; shift
 
-	ip link set dev "$name" up
-	defer ip link set dev "$name" down
+	if ! ip_link_is_up "$name"; then
+		ip link set dev "$name" up
+		defer ip link set dev "$name" down
+	fi
+}
+
+ip_link_set_down()
+{
+	local name=$1; shift
+
+	if ip_link_is_up "$name"; then
+		ip link set dev "$name" down
+		defer ip link set dev "$name" up
+	fi
 }
 
 ip_addr_add()
@@ -498,3 +519,9 @@ ip_route_add()
 	ip route add "$@"
 	defer ip route del "$@"
 }
+
+bridge_vlan_add()
+{
+	bridge vlan add "$@"
+	defer bridge vlan del "$@"
+}