net: dsa: add cross-chip multicast support

Similarly to how cross-chip VLAN works, define a bitmap of multicast
group members for a switch, now including its DSA ports, so that
multicast traffic can be sent to all switches of the fabric.

A switch may drop the frames if no user port is a member.

This brings support for multicast in a multi-chip environment.
As of now, all switches of the fabric must support the multicast
operations in order to program a single fabric port.

Reported-by: Jason Cobham <jcobham@questertangent.com>
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Tested-by: Jason Cobham <jcobham@questertangent.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 10 deletions

diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index f1029a8d0e20..97e2e9c8cf3f 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -122,19 +122,30 @@ static int dsa_switch_mdb_add(struct dsa_switch *ds,
 {
         const struct switchdev_obj_port_mdb *mdb = info->mdb;
         struct switchdev_trans *trans = info->trans;
+        DECLARE_BITMAP(group, ds->num_ports);
+        int port, err;
 
-        /* Do not care yet about other switch chips of the fabric */
-        if (ds->index != info->sw_index)
-                return 0;
+        /* Build a mask of Multicast group members */
+        bitmap_zero(group, ds->num_ports);
+        if (ds->index == info->sw_index)
+                set_bit(info->port, group);
+        for (port = 0; port < ds->num_ports; port++)
+                if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
+                        set_bit(port, group);
 
         if (switchdev_trans_ph_prepare(trans)) {
                 if (!ds->ops->port_mdb_prepare || !ds->ops->port_mdb_add)
                         return -EOPNOTSUPP;
 
-                return ds->ops->port_mdb_prepare(ds, info->port, mdb, trans);
+                for_each_set_bit(port, group, ds->num_ports) {
+                        err = ds->ops->port_mdb_prepare(ds, port, mdb, trans);
+                        if (err)
+                                return err;
+                }
         }
 
-        ds->ops->port_mdb_add(ds, info->port, mdb, trans);
+        for_each_set_bit(port, group, ds->num_ports)
+                ds->ops->port_mdb_add(ds, port, mdb, trans);
 
         return 0;
 }
@@ -144,14 +155,13 @@ static int dsa_switch_mdb_del(struct dsa_switch *ds,
 {
         const struct switchdev_obj_port_mdb *mdb = info->mdb;
 
-        /* Do not care yet about other switch chips of the fabric */
-        if (ds->index != info->sw_index)
-                return 0;
-
         if (!ds->ops->port_mdb_del)
                 return -EOPNOTSUPP;
 
-        return ds->ops->port_mdb_del(ds, info->port, mdb);
+        if (ds->index == info->sw_index)
+                return ds->ops->port_mdb_del(ds, info->port, mdb);
+
+        return 0;
 }
 
 static int dsa_switch_vlan_add(struct dsa_switch *ds,