batman-adv: Distributed ARP Table - implement local storage

Since batman-adv cannot inter-operate with the host ARP table, this patch
introduces a batman-adv private storage for ARP entries exchanged within DAT.
This storage will represent the node local cache in the DAT protocol.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index b57d93bdafa6..9ed1bb275d31 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -249,9 +249,13 @@ struct batadv_priv_vis {
 /**
  * struct batadv_priv_dat - per mesh interface DAT private data
  * @addr: node DAT address
+ * @hash: hashtable representing the local ARP cache
+ * @work: work queue callback item for cache purging
  */
 struct batadv_priv_dat {
 	batadv_dat_addr_t addr;
+	struct batadv_hashtable *hash;
+	struct delayed_work work;
 };
 
 struct batadv_priv {
@@ -465,6 +469,25 @@ struct batadv_algo_ops {
 };
 
 /**
+ * struct batadv_dat_entry - it is a single entry of batman-adv ARP backend. It
+ * is used to stored ARP entries needed for the global DAT cache
+ * @ip: the IPv4 corresponding to this DAT/ARP entry
+ * @mac_addr: the MAC address associated to the stored IPv4
+ * @last_update: time in jiffies when this entry was refreshed last time
+ * @hash_entry: hlist node for batadv_priv_dat::hash
+ * @refcount: number of contexts the object is used
+ * @rcu: struct used for freeing in an RCU-safe manner
+ */
+struct batadv_dat_entry {
+	__be32 ip;
+	uint8_t mac_addr[ETH_ALEN];
+	unsigned long last_update;
+	struct hlist_node hash_entry;
+	atomic_t refcount;
+	struct rcu_head rcu;
+};
+
+/**
  * struct batadv_dat_candidate - candidate destination for DAT operations
  * @type: the type of the selected candidate. It can one of the following:
  *	  - BATADV_DAT_CANDIDATE_NOT_FOUND