batman-adv: allow multiple entries in tt_global_entries

as backbone gateways will all independently announce the same clients,
also the tt global table must be able to hold multiple originators per
client entry.
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

net/batman-adv/types.h

@@ -241,9 +241,16 @@ struct tt_local_entry {
 
 struct tt_global_entry {
 	struct tt_common_entry common;
+	struct hlist_head orig_list;
+	spinlock_t list_lock;	/* protects the list */
+	unsigned long roam_at; /* time at which TT_GLOBAL_ROAM was set */
+};
+
+struct tt_orig_list_entry {
 	struct orig_node *orig_node;
 	uint8_t ttvn;
-	unsigned long roam_at; /* time at which TT_GLOBAL_ROAM was set */
+	struct rcu_head rcu;
+	struct hlist_node list;
 };
 
 struct backbone_gw {