batman-adv: substitute tt_poss_change with a per-tt_entry flag

tt_poss_change is a node-wide flag which tells whether the node is in a roaming
state (a client recently moved to/away from it) in order to let it apply special
re-routing rules. However this flag does not give a clear idea of the current
state because it is not possible to understand *which client* is actually
involved in the roaming. For this reason a better approach has been chosen:
instead of using a node-wide variable, the roaming state is now given by a
per-tt_entry ROAM flag which, in case of packet coming through the node, tells
the node whether the real destination is in roaming state or not.

With this flag change, batadv_check_unicast_ttvn() has also been rearranged in
order to better fit the new re-routing logic and to be much more readable.

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

1 files changed, 32 insertions, 14 deletions

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index f8b9c32c29a5..d7418511448d 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -306,8 +306,6 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
                 head = &tt_global_entry->orig_list;
                 rcu_read_lock();
                 hlist_for_each_entry_rcu(orig_entry, node, head, list) {
-                        orig_entry->orig_node->tt_poss_change = true;
-
                         batadv_send_roam_adv(bat_priv,
                                              tt_global_entry->common.addr,
                                              orig_entry->orig_node);
@@ -512,8 +510,11 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv,
         curr_flags = tt_local_entry->common.flags;
 
         flags = BATADV_TT_CLIENT_DEL;
-        if (roaming)
+        if (roaming) {
                 flags |= BATADV_TT_CLIENT_ROAM;
+                /* mark the local client as ROAMed */
+                tt_local_entry->common.flags |= BATADV_TT_CLIENT_ROAM;
+        }
 
         batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags, message);
 
@@ -1945,7 +1946,8 @@ bool batadv_is_my_client(struct batadv_priv *bat_priv, const uint8_t *addr)
         /* Check if the client has been logically deleted (but is kept for
          * consistency purpose)
          */
-        if (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING)
+        if ((tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING) ||
+            (tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM))
                 goto out;
         ret = true;
 out:
@@ -1996,10 +1998,6 @@ void batadv_handle_tt_response(struct batadv_priv *bat_priv,
 
         /* Recalculate the CRC for this orig_node and store it */
         orig_node->tt_crc = batadv_tt_global_crc(bat_priv, orig_node);
-        /* Roaming phase is over: tables are in sync again. I can
-         * unset the flag
-         */
-        orig_node->tt_poss_change = false;
 out:
         if (orig_node)
                 batadv_orig_node_free_ref(orig_node);
@@ -2290,7 +2288,6 @@ static int batadv_tt_commit_changes(struct batadv_priv *bat_priv,
         batadv_dbg(BATADV_DBG_TT, bat_priv,
                    "Local changes committed, updating to ttvn %u\n",
                    (uint8_t)atomic_read(&bat_priv->tt.vn));
-        bat_priv->tt.poss_change = false;
 
         /* reset the sending counter */
         atomic_set(&bat_priv->tt.ogm_append_cnt, BATADV_TT_OGM_APPEND_MAX);
@@ -2402,11 +2399,6 @@ void batadv_tt_update_orig(struct batadv_priv *bat_priv,
                  */
                 if (orig_node->tt_crc != tt_crc)
                         goto request_table;
-
-                /* Roaming phase is over: tables are in sync again. I can
-                 * unset the flag
-                 */
-                orig_node->tt_poss_change = false;
         } else {
                 /* if we missed more than one change or our tables are not
                  * in sync anymore -> request fresh tt data
@@ -2445,6 +2437,32 @@ out:
         return ret;
 }
 
+/**
+ * batadv_tt_local_client_is_roaming - tells whether the client is roaming
+ * @bat_priv: the bat priv with all the soft interface information
+ * @addr: the MAC address of the local client to query
+ *
+ * Returns true if the local client is known to be roaming (it is not served by
+ * this node anymore) or not. If yes, the client is still present in the table
+ * to keep the latter consistent with the node TTVN
+ */
+bool batadv_tt_local_client_is_roaming(struct batadv_priv *bat_priv,
+                                       uint8_t *addr)
+{
+        struct batadv_tt_local_entry *tt_local_entry;
+        bool ret = false;
+
+        tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr);
+        if (!tt_local_entry)
+                goto out;
+
+        ret = tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM;
+        batadv_tt_local_entry_free_ref(tt_local_entry);
+out:
+        return ret;
+
+}
+
 bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
                                           struct batadv_orig_node *orig_node,
                                           const unsigned char *addr)