1 files changed, 134 insertions, 16 deletions

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 4c28251dd8e6..a3c965dd1d96 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -401,6 +401,35 @@ static uint16_t batadv_tt_entries(uint16_t tt_len)
         return tt_len / batadv_tt_len(1);
 }
 
+/**
+ * batadv_tt_local_table_transmit_size - calculates the local translation table
+ *  size when transmitted over the air
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Returns local translation table size in bytes.
+ */
+static int batadv_tt_local_table_transmit_size(struct batadv_priv *bat_priv)
+{
+        uint16_t num_vlan = 0, tt_local_entries = 0;
+        struct batadv_softif_vlan *vlan;
+        int hdr_size;
+
+        rcu_read_lock();
+        hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
+                num_vlan++;
+                tt_local_entries += atomic_read(&vlan->tt.num_entries);
+        }
+        rcu_read_unlock();
+
+        /* header size of tvlv encapsulated tt response payload */
+        hdr_size = sizeof(struct batadv_unicast_tvlv_packet);
+        hdr_size += sizeof(struct batadv_tvlv_hdr);
+        hdr_size += sizeof(struct batadv_tvlv_tt_data);
+        hdr_size += num_vlan * sizeof(struct batadv_tvlv_tt_vlan_data);
+
+        return hdr_size + batadv_tt_len(tt_local_entries);
+}
+
 static int batadv_tt_local_init(struct batadv_priv *bat_priv)
 {
         if (bat_priv->tt.local_hash)
@@ -439,8 +468,10 @@ static void batadv_tt_global_free(struct batadv_priv *bat_priv,
  * @vid: VLAN identifier
  * @ifindex: index of the interface where the client is connected to (useful to
  *  identify wireless clients)
+ *
+ * Returns true if the client was successfully added, false otherwise.
  */
-void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
+bool batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
                          unsigned short vid, int ifindex)
 {
         struct batadv_priv *bat_priv = netdev_priv(soft_iface);
@@ -448,8 +479,8 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
         struct batadv_tt_global_entry *tt_global;
         struct hlist_head *head;
         struct batadv_tt_orig_list_entry *orig_entry;
-        int hash_added;
-        bool roamed_back = false;
+        int hash_added, table_size, packet_size_max;
+        bool ret = false, roamed_back = false;
 
         tt_local = batadv_tt_local_hash_find(bat_priv, addr, vid);
         tt_global = batadv_tt_global_hash_find(bat_priv, addr, vid);
@@ -484,6 +515,17 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
                 goto check_roaming;
         }
 
+        /* Ignore the client if we cannot send it in a full table response. */
+        table_size = batadv_tt_local_table_transmit_size(bat_priv);
+        table_size += batadv_tt_len(1);
+        packet_size_max = atomic_read(&bat_priv->packet_size_max);
+        if (table_size > packet_size_max) {
+                net_ratelimited_function(batadv_info, soft_iface,
+                                         "Local translation table size (%i) exceeds maximum packet size (%i); Ignoring new local tt entry: %pM\n",
+                                         table_size, packet_size_max, addr);
+                goto out;
+        }
+
         tt_local = kmalloc(sizeof(*tt_local), GFP_ATOMIC);
         if (!tt_local)
                 goto out;
@@ -550,11 +592,14 @@ check_roaming:
                 }
         }
 
+        ret = true;
+
 out:
         if (tt_local)
                 batadv_tt_local_entry_free_ref(tt_local);
         if (tt_global)
                 batadv_tt_global_entry_free_ref(tt_global);
+        return ret;
 }
 
 /**
@@ -926,8 +971,16 @@ out:
         return curr_flags;
 }
 
+/**
+ * batadv_tt_local_purge_list - purge inactive tt local entries
+ * @bat_priv: the bat priv with all the soft interface information
+ * @head: pointer to the list containing the local tt entries
+ * @timeout: parameter deciding whether a given tt local entry is considered
+ *  inactive or not
+ */
 static void batadv_tt_local_purge_list(struct batadv_priv *bat_priv,
-                                       struct hlist_head *head)
+                                       struct hlist_head *head,
+                                       int timeout)
 {
         struct batadv_tt_local_entry *tt_local_entry;
         struct batadv_tt_common_entry *tt_common_entry;
@@ -945,8 +998,7 @@ static void batadv_tt_local_purge_list(struct batadv_priv *bat_priv,
                 if (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING)
                         continue;
 
-                if (!batadv_has_timed_out(tt_local_entry->last_seen,
-                                          BATADV_TT_LOCAL_TIMEOUT))
+                if (!batadv_has_timed_out(tt_local_entry->last_seen, timeout))
                         continue;
 
                 batadv_tt_local_set_pending(bat_priv, tt_local_entry,
@@ -954,7 +1006,14 @@ static void batadv_tt_local_purge_list(struct batadv_priv *bat_priv,
         }
 }
 
-static void batadv_tt_local_purge(struct batadv_priv *bat_priv)
+/**
+ * batadv_tt_local_purge - purge inactive tt local entries
+ * @bat_priv: the bat priv with all the soft interface information
+ * @timeout: parameter deciding whether a given tt local entry is considered
+ *  inactive or not
+ */
+static void batadv_tt_local_purge(struct batadv_priv *bat_priv,
+                                  int timeout)
 {
         struct batadv_hashtable *hash = bat_priv->tt.local_hash;
         struct hlist_head *head;
@@ -966,7 +1025,7 @@ static void batadv_tt_local_purge(struct batadv_priv *bat_priv)
                 list_lock = &hash->list_locks[i];
 
                 spin_lock_bh(list_lock);
-                batadv_tt_local_purge_list(bat_priv, head);
+                batadv_tt_local_purge_list(bat_priv, head, timeout);
                 spin_unlock_bh(list_lock);
         }
 }
@@ -2383,6 +2442,15 @@ static bool batadv_send_other_tt_response(struct batadv_priv *bat_priv,
                                         req_dst_orig_node);
         }
 
+        /* Don't send the response, if larger than fragmented packet. */
+        tt_len = sizeof(struct batadv_unicast_tvlv_packet) + tvlv_len;
+        if (tt_len > atomic_read(&bat_priv->packet_size_max)) {
+                net_ratelimited_function(batadv_info, bat_priv->soft_iface,
+                                         "Ignoring TT_REQUEST from %pM; Response size exceeds max packet size.\n",
+                                         res_dst_orig_node->orig);
+                goto out;
+        }
+
         tvlv_tt_data->flags = BATADV_TT_RESPONSE;
         tvlv_tt_data->ttvn = req_ttvn;
 
@@ -2859,7 +2927,7 @@ static void batadv_tt_purge(struct work_struct *work)
         priv_tt = container_of(delayed_work, struct batadv_priv_tt, work);
         bat_priv = container_of(priv_tt, struct batadv_priv, tt);
 
-        batadv_tt_local_purge(bat_priv);
+        batadv_tt_local_purge(bat_priv, BATADV_TT_LOCAL_TIMEOUT);
         batadv_tt_global_purge(bat_priv);
         batadv_tt_req_purge(bat_priv);
         batadv_tt_roam_purge(bat_priv);
@@ -2972,18 +3040,18 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv)
 }
 
 /**
- * batadv_tt_local_commit_changes - commit all pending local tt changes which
- *  have been queued in the time since the last commit
+ * batadv_tt_local_commit_changes_nolock - commit all pending local tt changes
+ *  which have been queued in the time since the last commit
  * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Caller must hold tt->commit_lock.
  */
-void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
+static void batadv_tt_local_commit_changes_nolock(struct batadv_priv *bat_priv)
 {
-        spin_lock_bh(&bat_priv->tt.commit_lock);
-
         if (atomic_read(&bat_priv->tt.local_changes) < 1) {
                 if (!batadv_atomic_dec_not_zero(&bat_priv->tt.ogm_append_cnt))
                         batadv_tt_tvlv_container_update(bat_priv);
-                goto out;
+                return;
         }
 
         batadv_tt_local_set_flags(bat_priv, BATADV_TT_CLIENT_NEW, false, true);
@@ -3000,8 +3068,17 @@ void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
         /* reset the sending counter */
         atomic_set(&bat_priv->tt.ogm_append_cnt, BATADV_TT_OGM_APPEND_MAX);
         batadv_tt_tvlv_container_update(bat_priv);
+}
 
-out:
+/**
+ * batadv_tt_local_commit_changes - commit all pending local tt changes which
+ *  have been queued in the time since the last commit
+ * @bat_priv: the bat priv with all the soft interface information
+ */
+void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
+{
+        spin_lock_bh(&bat_priv->tt.commit_lock);
+        batadv_tt_local_commit_changes_nolock(bat_priv);
         spin_unlock_bh(&bat_priv->tt.commit_lock);
 }
 
@@ -3197,6 +3274,47 @@ out:
 }
 
 /**
+ * batadv_tt_local_resize_to_mtu - resize the local translation table fit the
+ *  maximum packet size that can be transported through the mesh
+ * @soft_iface: netdev struct of the mesh interface
+ *
+ * Remove entries older than 'timeout' and half timeout if more entries need
+ * to be removed.
+ */
+void batadv_tt_local_resize_to_mtu(struct net_device *soft_iface)
+{
+        struct batadv_priv *bat_priv = netdev_priv(soft_iface);
+        int packet_size_max = atomic_read(&bat_priv->packet_size_max);
+        int table_size, timeout = BATADV_TT_LOCAL_TIMEOUT / 2;
+        bool reduced = false;
+
+        spin_lock_bh(&bat_priv->tt.commit_lock);
+
+        while (true) {
+                table_size = batadv_tt_local_table_transmit_size(bat_priv);
+                if (packet_size_max >= table_size)
+                        break;
+
+                batadv_tt_local_purge(bat_priv, timeout);
+                batadv_tt_local_purge_pending_clients(bat_priv);
+
+                timeout /= 2;
+                reduced = true;
+                net_ratelimited_function(batadv_info, soft_iface,
+                                         "Forced to purge local tt entries to fit new maximum fragment MTU (%i)\n",
+                                         packet_size_max);
+        }
+
+        /* commit these changes immediately, to avoid synchronization problem
+         * with the TTVN
+         */
+        if (reduced)
+                batadv_tt_local_commit_changes_nolock(bat_priv);
+
+        spin_unlock_bh(&bat_priv->tt.commit_lock);
+}
+
+/**
  * batadv_tt_tvlv_ogm_handler_v1 - process incoming tt tvlv container
  * @bat_priv: the bat priv with all the soft interface information
  * @orig: the orig_node of the ogm