When a port turns into an mrouter port, enable multicast flooding
on that port even if mcast_flood is disabled by user config. This
is necessary so that in a distributed system, the multicast packets
can be fowarded to the Querier when the multicast source is attached
to a Non-Querier bridge.
Consider the following scenario:
+--------------------+
| |
| Snooping | +------------+
| Bridge 1 |----| Listener 1 |
| (Querier) | +------------+
| |
+--------------------+
|
|
+--------------------+
| | mrouter | |
+-----------+ | +---------+ |
| MC Source |----| Snooping |
+-----------| | Bridge 2 |
| (Non-Querier) |
+--------------------+
In this scenario, Listener 1 will never receive multicast traffic
from MC Source if mcast_flood is disabled on the mrouter port on
Snooping Bridge 2.
Signed-off-by: Joseph Huang <Joseph.Huang@xxxxxxxxxx>
---
net/bridge/br_multicast.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index d7fbe1f3af18..719ded3204a0 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2680,6 +2680,21 @@ static void br_port_mc_router_state_change(struct net_bridge_port *port,
switchdev_port_attr_set(port->dev, &attr, NULL);
+ /* Force mcast_flood if mrouter port
+ * this does not prevent netlink from changing it again
+ */
+ if (is_mc_router && !(port->flags & BR_MCAST_FLOOD)) {
+ attr.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS;
+ attr.u.brport_flags.val = BR_MCAST_FLOOD;
+ attr.u.brport_flags.mask = BR_MCAST_FLOOD;
+ switchdev_port_attr_set(port->dev, &attr, NULL);
+ } else if (!is_mc_router) {
+ attr.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS;
+ attr.u.brport_flags.val = port->flags & BR_MCAST_FLOOD;
+ attr.u.brport_flags.mask = BR_MCAST_FLOOD;
+ switchdev_port_attr_set(port->dev, &attr, NULL);
+ }
+
/* Add/delete the router port to/from all multicast group
* called whle br->multicast_lock is held
*/
--
2.17.1
