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>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 1085ffeef956..44d6eb0eb852 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -16,9 +16,27 @@
 #include <linux/netdevice.h>
 #include <uapi/linux/if_bridge.h>
 
+struct br_ip {
+        union {
+                __be32  ip4;
+#if IS_ENABLED(CONFIG_IPV6)
+                struct in6_addr ip6;
+#endif
+        } u;
+        __be16          proto;
+        __u16           vid;
+};
+
+struct br_ip_list {
+        struct list_head list;
+        struct br_ip addr;
+};
+
 extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));
 
 typedef int br_should_route_hook_t(struct sk_buff *skb);
 extern br_should_route_hook_t __rcu *br_should_route_hook;
+int br_multicast_list_adjacent(struct net_device *dev,
+                               struct list_head *br_ip_list);
 
 #endif