net: bridge: mst: Allow changing a VLAN's MSTI

Allow a VLAN to move out of the CST (MSTI 0), to an independent tree.

The user manages the VID to MSTI mappings via a global VLAN
setting. The proposed iproute2 interface would be:

    bridge vlan global set dev br0 vid <VID> msti <MSTI>

Changing the state in non-zero MSTIs is still not supported, but will
be addressed in upcoming changes.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 0f9f596f86bc..d7a7b5d7ddb3 100644
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -46,6 +46,48 @@ int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
 	return 0;
 }
 
+static void br_mst_vlan_sync_state(struct net_bridge_vlan *pv, u16 msti)
+{
+	struct net_bridge_vlan_group *vg = nbp_vlan_group(pv->port);
+	struct net_bridge_vlan *v;
+
+	list_for_each_entry(v, &vg->vlan_list, vlist) {
+		/* If this port already has a defined state in this
+		 * MSTI (through some other VLAN membership), inherit
+		 * it.
+		 */
+		if (v != pv && v->brvlan->msti == msti) {
+			br_mst_vlan_set_state(pv->port, pv, v->state);
+			return;
+		}
+	}
+
+	/* Otherwise, start out in a new MSTI with all ports disabled. */
+	return br_mst_vlan_set_state(pv->port, pv, BR_STATE_DISABLED);
+}
+
+int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)
+{
+	struct net_bridge_vlan_group *vg;
+	struct net_bridge_vlan *pv;
+	struct net_bridge_port *p;
+
+	if (mv->msti == msti)
+		return 0;
+
+	mv->msti = msti;
+
+	list_for_each_entry(p, &mv->br->port_list, list) {
+		vg = nbp_vlan_group(p);
+
+		pv = br_vlan_find(vg, mv->vid);
+		if (pv)
+			br_mst_vlan_sync_state(pv, msti);
+	}
+
+	return 0;
+}
+
 void br_mst_vlan_init_state(struct net_bridge_vlan *v)
 {
 	/* VLANs always start out in MSTI 0 (CST) */