bridge: add export of multicast database adjacent to net_dev
With this new, exported function br_multicast_list_adjacent(net_dev) a
list of IPv4/6 addresses is returned. This list contains all multicast
addresses sensed by the bridge multicast snooping feature on all bridge
ports of the bridge interface of net_dev, excluding addresses from the
specified net_device itself.
Adding bridge support to the batman-adv multicast optimization requires
batman-adv knowing about the existence of bridged-in multicast
listeners to be able to reliably serve them with multicast packets.
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index b3f17c9..772476b 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -11,6 +11,7 @@
*/
#include <linux/err.h>
+#include <linux/export.h>
#include <linux/if_ether.h>
#include <linux/igmp.h>
#include <linux/jhash.h>
@@ -2141,3 +2142,60 @@
return err;
}
+
+/**
+ * br_multicast_list_adjacent - Returns snooped multicast addresses
+ * @dev: The bridge port adjacent to which to retrieve addresses
+ * @br_ip_list: The list to store found, snooped multicast IP addresses in
+ *
+ * Creates a list of IP addresses (struct br_ip_list) sensed by the multicast
+ * snooping feature on all bridge ports of dev's bridge device, excluding
+ * the addresses from dev itself.
+ *
+ * Returns the number of items added to br_ip_list.
+ *
+ * Notes:
+ * - br_ip_list needs to be initialized by caller
+ * - br_ip_list might contain duplicates in the end
+ * (needs to be taken care of by caller)
+ * - br_ip_list needs to be freed by caller
+ */
+int br_multicast_list_adjacent(struct net_device *dev,
+ struct list_head *br_ip_list)
+{
+ struct net_bridge *br;
+ struct net_bridge_port *port;
+ struct net_bridge_port_group *group;
+ struct br_ip_list *entry;
+ int count = 0;
+
+ rcu_read_lock();
+ if (!br_ip_list || !br_port_exists(dev))
+ goto unlock;
+
+ port = br_port_get_rcu(dev);
+ if (!port || !port->br)
+ goto unlock;
+
+ br = port->br;
+
+ list_for_each_entry_rcu(port, &br->port_list, list) {
+ if (!port->dev || port->dev == dev)
+ continue;
+
+ hlist_for_each_entry_rcu(group, &port->mglist, mglist) {
+ entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+ if (!entry)
+ goto unlock;
+
+ entry->addr = group->addr;
+ list_add(&entry->list, br_ip_list);
+ count++;
+ }
+ }
+
+unlock:
+ rcu_read_unlock();
+ return count;
+}
+EXPORT_SYMBOL_GPL(br_multicast_list_adjacent);