Merge tag 'batman-adv-for-davem' of git://git.open-mesh.org/linux-merge

Included changes:
- hash computation improvements
- Bridge Loop Avoidance set-up phase optimisations
- Roaming handling code redesign
- some code cleanups

Signed-off-by: David S. Miller <davem@davemloft.net>

net/batman-adv/bridge_loop_avoidance.c

@@ -40,15 +40,11 @@ static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
 /* return the index of the claim */
 static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
 {
-	const unsigned char *key = data;
+	struct batadv_claim *claim = (struct batadv_claim *)data;
 	uint32_t hash = 0;
-	size_t i;
 
-	for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
-		hash += key[i];
-		hash += (hash << 10);
-		hash ^= (hash >> 6);
-	}
+	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
+	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
 
 	hash += (hash << 3);
 	hash ^= (hash >> 11);
@@ -61,15 +57,11 @@ static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
 static inline uint32_t batadv_choose_backbone_gw(const void *data,
 						 uint32_t size)
 {
-	const unsigned char *key = data;
+	struct batadv_claim *claim = (struct batadv_claim *)data;
 	uint32_t hash = 0;
-	size_t i;
 
-	for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
-		hash += key[i];
-		hash += (hash << 10);
-		hash ^= (hash >> 6);
-	}
+	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
+	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));
 
 	hash += (hash << 3);
 	hash ^= (hash >> 11);
@@ -362,7 +354,7 @@ out:
  */
 static struct batadv_backbone_gw *
 batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
-			   short vid)
+			   short vid, bool own_backbone)
 {
 	struct batadv_backbone_gw *entry;
 	struct batadv_orig_node *orig_node;
@@ -386,6 +378,7 @@ batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
 	entry->crc = BATADV_BLA_CRC_INIT;
 	entry->bat_priv = bat_priv;
 	atomic_set(&entry->request_sent, 0);
+	atomic_set(&entry->wait_periods, 0);
 	memcpy(entry->orig, orig, ETH_ALEN);
 
 	/* one for the hash, one for returning */
@@ -409,6 +402,16 @@ batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
 					  "became a backbone gateway");
 		batadv_orig_node_free_ref(orig_node);
 	}
+
+	if (own_backbone) {
+		batadv_bla_send_announce(bat_priv, entry);
+
+		/* this will be decreased in the worker thread */
+		atomic_inc(&entry->request_sent);
+		atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
+		atomic_inc(&bat_priv->bla.num_requests);
+	}
+
 	return entry;
 }
 
@@ -424,7 +427,7 @@ batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
 
 	backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
 						 primary_if->net_dev->dev_addr,
-						 vid);
+						 vid, true);
 	if (unlikely(!backbone_gw))
 		return;
 
@@ -632,7 +635,8 @@ static int batadv_handle_announce(struct batadv_priv *bat_priv,
 	if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
 		return 0;
 
-	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);
+	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
+						 false);
 
 	if (unlikely(!backbone_gw))
 		return 1;
@@ -730,7 +734,8 @@ static int batadv_handle_claim(struct batadv_priv *bat_priv,
 
 	/* register the gateway if not yet available, and add the claim. */
 
-	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);
+	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
+						 false);
 
 	if (unlikely(!backbone_gw))
 		return 1;
@@ -1140,6 +1145,24 @@ static void batadv_bla_periodic_work(struct work_struct *work)
 			backbone_gw->lasttime = jiffies;
 
 			batadv_bla_send_announce(bat_priv, backbone_gw);
+
+			/* request_sent is only set after creation to avoid
+			 * problems when we are not yet known as backbone gw
+			 * in the backbone.
+			 *
+			 * We can reset this now after we waited some periods
+			 * to give bridge forward delays and bla group forming
+			 * some grace time.
+			 */
+
+			if (atomic_read(&backbone_gw->request_sent) == 0)
+				continue;
+
+			if (!atomic_dec_and_test(&backbone_gw->wait_periods))
+				continue;
+
+			atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
+			atomic_set(&backbone_gw->request_sent, 0);
 		}
 		rcu_read_unlock();
 	}

net/batman-adv/hard-interface.c

@@ -59,6 +59,45 @@ out:
 	return hard_iface;
 }
 
+/**
+ * batadv_is_on_batman_iface - check if a device is a batman iface descendant
+ * @net_dev: the device to check
+ *
+ * If the user creates any virtual device on top of a batman-adv interface, it
+ * is important to prevent this new interface to be used to create a new mesh
+ * network (this behaviour would lead to a batman-over-batman configuration).
+ * This function recursively checks all the fathers of the device passed as
+ * argument looking for a batman-adv soft interface.
+ *
+ * Returns true if the device is descendant of a batman-adv mesh interface (or
+ * if it is a batman-adv interface itself), false otherwise
+ */
+static bool batadv_is_on_batman_iface(const struct net_device *net_dev)
+{
+	struct net_device *parent_dev;
+	bool ret;
+
+	/* check if this is a batman-adv mesh interface */
+	if (batadv_softif_is_valid(net_dev))
+		return true;
+
+	/* no more parents..stop recursion */
+	if (net_dev->iflink == net_dev->ifindex)
+		return false;
+
+	/* recurse over the parent device */
+	parent_dev = dev_get_by_index(&init_net, net_dev->iflink);
+	/* if we got a NULL parent_dev there is something broken.. */
+	if (WARN(!parent_dev, "Cannot find parent device"))
+		return false;
+
+	ret = batadv_is_on_batman_iface(parent_dev);
+
+	if (parent_dev)
+		dev_put(parent_dev);
+	return ret;
+}
+
 static int batadv_is_valid_iface(const struct net_device *net_dev)
 {
 	if (net_dev->flags & IFF_LOOPBACK)
@@ -71,7 +110,7 @@ static int batadv_is_valid_iface(const struct net_device *net_dev)
 		return 0;
 
 	/* no batman over batman */
-	if (batadv_softif_is_valid(net_dev))
+	if (batadv_is_on_batman_iface(net_dev))
 		return 0;
 
 	return 1;

net/batman-adv/hash.h

@@ -81,6 +81,28 @@ static inline void batadv_hash_delete(struct batadv_hashtable *hash,
 	batadv_hash_destroy(hash);
 }
 
+/**
+ *	batadv_hash_bytes - hash some bytes and add them to the previous hash
+ *	@hash: previous hash value
+ *	@data: data to be hashed
+ *	@size: number of bytes to be hashed
+ *
+ *	Returns the new hash value.
+ */
+static inline uint32_t batadv_hash_bytes(uint32_t hash, void *data,
+					 uint32_t size)
+{
+	const unsigned char *key = data;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		hash += key[i];
+		hash += (hash << 10);
+		hash ^= (hash >> 6);
+	}
+	return hash;
+}
+
 /**
  *	batadv_hash_add - adds data to the hashtable
  *	@hash: storage hash table

net/batman-adv/main.h

@@ -95,6 +95,7 @@
 #define BATADV_BLA_PERIOD_LENGTH	10000	/* 10 seconds */
 #define BATADV_BLA_BACKBONE_TIMEOUT	(BATADV_BLA_PERIOD_LENGTH * 3)
 #define BATADV_BLA_CLAIM_TIMEOUT	(BATADV_BLA_PERIOD_LENGTH * 10)
+#define BATADV_BLA_WAIT_PERIODS		3
 
 #define BATADV_DUPLIST_SIZE		16
 #define BATADV_DUPLIST_TIMEOUT		500	/* 500 ms */

net/batman-adv/originator.c

@@ -221,7 +221,6 @@ struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
 	atomic_set(&orig_node->refcount, 2);
 
 	orig_node->tt_initialised = false;
-	orig_node->tt_poss_change = false;
 	orig_node->bat_priv = bat_priv;
 	memcpy(orig_node->orig, addr, ETH_ALEN);
 	batadv_dat_init_orig_node_addr(orig_node);

net/batman-adv/routing.c

@@ -711,12 +711,6 @@ int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if)
 			     BATADV_TT_CLIENT_ROAM,
 			     atomic_read(&orig_node->last_ttvn) + 1);
 
-	/* Roaming phase starts: I have new information but the ttvn has not
-	 * been incremented yet. This flag will make me check all the incoming
-	 * packets for the correct destination.
-	 */
-	bat_priv->tt.poss_change = true;
-
 	batadv_orig_node_free_ref(orig_node);
 out:
 	/* returning NET_RX_DROP will make the caller function kfree the skb */
@@ -899,14 +893,67 @@ out:
 	return ret;
 }
 
+/**
+ * batadv_reroute_unicast_packet - update the unicast header for re-routing
+ * @bat_priv: the bat priv with all the soft interface information
+ * @unicast_packet: the unicast header to be updated
+ * @dst_addr: the payload destination
+ *
+ * Search the translation table for dst_addr and update the unicast header with
+ * the new corresponding information (originator address where the destination
+ * client currently is and its known TTVN)
+ *
+ * Returns true if the packet header has been updated, false otherwise
+ */
+static bool
+batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
+			      struct batadv_unicast_packet *unicast_packet,
+			      uint8_t *dst_addr)
+{
+	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_hard_iface *primary_if = NULL;
+	bool ret = false;
+	uint8_t *orig_addr, orig_ttvn;
+
+	if (batadv_is_my_client(bat_priv, dst_addr)) {
+		primary_if = batadv_primary_if_get_selected(bat_priv);
+		if (!primary_if)
+			goto out;
+		orig_addr = primary_if->net_dev->dev_addr;
+		orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
+	} else {
+		orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr);
+		if (!orig_node)
+			goto out;
+
+		if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
+			goto out;
+
+		orig_addr = orig_node->orig;
+		orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
+	}
+
+	/* update the packet header */
+	memcpy(unicast_packet->dest, orig_addr, ETH_ALEN);
+	unicast_packet->ttvn = orig_ttvn;
+
+	ret = true;
+out:
+	if (primary_if)
+		batadv_hardif_free_ref(primary_if);
+	if (orig_node)
+		batadv_orig_node_free_ref(orig_node);
+
+	return ret;
+}
+
 static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 				     struct sk_buff *skb) {
-	uint8_t curr_ttvn;
+	uint8_t curr_ttvn, old_ttvn;
 	struct batadv_orig_node *orig_node;
 	struct ethhdr *ethhdr;
 	struct batadv_hard_iface *primary_if;
 	struct batadv_unicast_packet *unicast_packet;
-	bool tt_poss_change;
 	int is_old_ttvn;
 
 	/* check if there is enough data before accessing it */
@@ -918,65 +965,89 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
 		return 0;
 
 	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet));
 
-	if (batadv_is_my_mac(unicast_packet->dest)) {
-		tt_poss_change = bat_priv->tt.poss_change;
-		curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
-	} else {
+	/* check if the destination client was served by this node and it is now
+	 * roaming. In this case, it means that the node has got a ROAM_ADV
+	 * message and that it knows the new destination in the mesh to re-route
+	 * the packet to
+	 */
+	if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) {
+		if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
+						  ethhdr->h_dest))
+			net_ratelimited_function(batadv_dbg, BATADV_DBG_TT,
+						 bat_priv,
+						 "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
+						 unicast_packet->dest,
+						 ethhdr->h_dest);
+		/* at this point the mesh destination should have been
+		 * substituted with the originator address found in the global
+		 * table. If not, let the packet go untouched anyway because
+		 * there is nothing the node can do
+		 */
+		return 1;
+	}
+
+	/* retrieve the TTVN known by this node for the packet destination. This
+	 * value is used later to check if the node which sent (or re-routed
+	 * last time) the packet had an updated information or not
+	 */
+	curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
+	if (!batadv_is_my_mac(unicast_packet->dest)) {
 		orig_node = batadv_orig_hash_find(bat_priv,
 						  unicast_packet->dest);
-
+		/* if it is not possible to find the orig_node representing the
+		 * destination, the packet can immediately be dropped as it will
+		 * not be possible to deliver it
+		 */
 		if (!orig_node)
 			return 0;
 
 		curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
-		tt_poss_change = orig_node->tt_poss_change;
 		batadv_orig_node_free_ref(orig_node);
 	}
 
-	/* Check whether I have to reroute the packet */
+	/* check if the TTVN contained in the packet is fresher than what the
+	 * node knows
+	 */
 	is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
-	if (is_old_ttvn || tt_poss_change) {
-		/* check if there is enough data before accessing it */
-		if (pskb_may_pull(skb, sizeof(struct batadv_unicast_packet) +
-				  ETH_HLEN) < 0)
-			return 0;
+	if (!is_old_ttvn)
+		return 1;
 
-		ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet));
+	old_ttvn = unicast_packet->ttvn;
+	/* the packet was forged based on outdated network information. Its
+	 * destination can possibly be updated and forwarded towards the new
+	 * target host
+	 */
+	if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
+					  ethhdr->h_dest)) {
+		net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
+					 "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
+					 unicast_packet->dest, ethhdr->h_dest,
+					 old_ttvn, curr_ttvn);
+		return 1;
+	}
 
-		/* we don't have an updated route for this client, so we should
-		 * not try to reroute the packet!!
-		 */
-		if (batadv_tt_global_client_is_roaming(bat_priv,
-						       ethhdr->h_dest))
-			return 1;
+	/* the packet has not been re-routed: either the destination is
+	 * currently served by this node or there is no destination at all and
+	 * it is possible to drop the packet
+	 */
+	if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
+		return 0;
 
-		orig_node = batadv_transtable_search(bat_priv, NULL,
-						     ethhdr->h_dest);
-
-		if (!orig_node) {
-			if (!batadv_is_my_client(bat_priv, ethhdr->h_dest))
-				return 0;
-			primary_if = batadv_primary_if_get_selected(bat_priv);
-			if (!primary_if)
-				return 0;
-			memcpy(unicast_packet->dest,
-			       primary_if->net_dev->dev_addr, ETH_ALEN);
-			batadv_hardif_free_ref(primary_if);
-		} else {
-			memcpy(unicast_packet->dest, orig_node->orig,
-			       ETH_ALEN);
-			curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
-			batadv_orig_node_free_ref(orig_node);
-		}
+	/* update the header in order to let the packet be delivered to this
+	 * node's soft interface
+	 */
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if)
+		return 0;
 
-		net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv,
-					 "TTVN mismatch (old_ttvn %u new_ttvn %u)! Rerouting unicast packet (for %pM) to %pM\n",
-					 unicast_packet->ttvn, curr_ttvn,
-					 ethhdr->h_dest, unicast_packet->dest);
+	memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN);
+
+	batadv_hardif_free_ref(primary_if);
+
+	unicast_packet->ttvn = curr_ttvn;
 
-		unicast_packet->ttvn = curr_ttvn;
-	}
 	return 1;
 }
 

net/batman-adv/soft-interface.c

@@ -505,7 +505,6 @@ struct net_device *batadv_softif_create(const char *name)
 #endif
 	bat_priv->tt.last_changeset = NULL;
 	bat_priv->tt.last_changeset_len = 0;
-	bat_priv->tt.poss_change = false;
 
 	bat_priv->primary_if = NULL;
 	bat_priv->num_ifaces = 0;

net/batman-adv/sysfs.c

@@ -688,7 +688,7 @@ int batadv_throw_uevent(struct batadv_priv *bat_priv, enum batadv_uev_type type,
 			enum batadv_uev_action action, const char *data)
 {
 	int ret = -ENOMEM;
-	struct batadv_hard_iface *primary_if = NULL;
+	struct batadv_hard_iface *primary_if;
 	struct kobject *bat_kobj;
 	char *uevent_env[4] = { NULL, NULL, NULL, NULL };
 

net/batman-adv/translation-table.c

@@ -238,92 +238,134 @@ static int batadv_tt_local_init(struct batadv_priv *bat_priv)
 	return 0;
 }
 
+static void batadv_tt_global_free(struct batadv_priv *bat_priv,
+				  struct batadv_tt_global_entry *tt_global,
+				  const char *message)
+{
+	batadv_dbg(BATADV_DBG_TT, bat_priv,
+		   "Deleting global tt entry %pM: %s\n",
+		   tt_global->common.addr, message);
+
+	batadv_hash_remove(bat_priv->tt.global_hash, batadv_compare_tt,
+			   batadv_choose_orig, tt_global->common.addr);
+	batadv_tt_global_entry_free_ref(tt_global);
+
+}
+
 void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
 			 int ifindex)
 {
 	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
-	struct batadv_tt_local_entry *tt_local_entry = NULL;
-	struct batadv_tt_global_entry *tt_global_entry = NULL;
+	struct batadv_tt_local_entry *tt_local;
+	struct batadv_tt_global_entry *tt_global;
 	struct hlist_head *head;
 	struct hlist_node *node;
 	struct batadv_tt_orig_list_entry *orig_entry;
 	int hash_added;
+	bool roamed_back = false;
 
-	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr);
+	tt_local = batadv_tt_local_hash_find(bat_priv, addr);
+	tt_global = batadv_tt_global_hash_find(bat_priv, addr);
 
-	if (tt_local_entry) {
-		tt_local_entry->last_seen = jiffies;
-		/* possibly unset the BATADV_TT_CLIENT_PENDING flag */
-		tt_local_entry->common.flags &= ~BATADV_TT_CLIENT_PENDING;
-		goto out;
+	if (tt_local) {
+		tt_local->last_seen = jiffies;
+		if (tt_local->common.flags & BATADV_TT_CLIENT_PENDING) {
+			batadv_dbg(BATADV_DBG_TT, bat_priv,
+				   "Re-adding pending client %pM\n", addr);
+			/* whatever the reason why the PENDING flag was set,
+			 * this is a client which was enqueued to be removed in
+			 * this orig_interval. Since it popped up again, the
+			 * flag can be reset like it was never enqueued
+			 */
+			tt_local->common.flags &= ~BATADV_TT_CLIENT_PENDING;
+			goto add_event;
+		}
+
+		if (tt_local->common.flags & BATADV_TT_CLIENT_ROAM) {
+			batadv_dbg(BATADV_DBG_TT, bat_priv,
+				   "Roaming client %pM came back to its original location\n",
+				   addr);
+			/* the ROAM flag is set because this client roamed away
+			 * and the node got a roaming_advertisement message. Now
+			 * that the client popped up again at its original
+			 * location such flag can be unset
+			 */
+			tt_local->common.flags &= ~BATADV_TT_CLIENT_ROAM;
+			roamed_back = true;
+		}
+		goto check_roaming;
 	}
 
-	tt_local_entry = kmalloc(sizeof(*tt_local_entry), GFP_ATOMIC);
-	if (!tt_local_entry)
+	tt_local = kmalloc(sizeof(*tt_local), GFP_ATOMIC);
+	if (!tt_local)
 		goto out;
 
 	batadv_dbg(BATADV_DBG_TT, bat_priv,
 		   "Creating new local tt entry: %pM (ttvn: %d)\n", addr,
 		   (uint8_t)atomic_read(&bat_priv->tt.vn));
 
-	memcpy(tt_local_entry->common.addr, addr, ETH_ALEN);
-	tt_local_entry->common.flags = BATADV_NO_FLAGS;
+	memcpy(tt_local->common.addr, addr, ETH_ALEN);
+	tt_local->common.flags = BATADV_NO_FLAGS;
 	if (batadv_is_wifi_iface(ifindex))
-		tt_local_entry->common.flags |= BATADV_TT_CLIENT_WIFI;
-	atomic_set(&tt_local_entry->common.refcount, 2);
-	tt_local_entry->last_seen = jiffies;
-	tt_local_entry->common.added_at = tt_local_entry->last_seen;
+		tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
+	atomic_set(&tt_local->common.refcount, 2);
+	tt_local->last_seen = jiffies;
+	tt_local->common.added_at = tt_local->last_seen;
 
 	/* the batman interface mac address should never be purged */
 	if (batadv_compare_eth(addr, soft_iface->dev_addr))
-		tt_local_entry->common.flags |= BATADV_TT_CLIENT_NOPURGE;
+		tt_local->common.flags |= BATADV_TT_CLIENT_NOPURGE;
 
 	/* The local entry has to be marked as NEW to avoid to send it in
 	 * a full table response going out before the next ttvn increment
 	 * (consistency check)
 	 */
-	tt_local_entry->common.flags |= BATADV_TT_CLIENT_NEW;
+	tt_local->common.flags |= BATADV_TT_CLIENT_NEW;
 
 	hash_added = batadv_hash_add(bat_priv->tt.local_hash, batadv_compare_tt,
-				     batadv_choose_orig,
-				     &tt_local_entry->common,
-				     &tt_local_entry->common.hash_entry);
+				     batadv_choose_orig, &tt_local->common,
+				     &tt_local->common.hash_entry);
 
 	if (unlikely(hash_added != 0)) {
 		/* remove the reference for the hash */
-		batadv_tt_local_entry_free_ref(tt_local_entry);
+		batadv_tt_local_entry_free_ref(tt_local);
 		goto out;
 	}
 
-	batadv_tt_local_event(bat_priv, addr, tt_local_entry->common.flags);
-
-	/* remove address from global hash if present */
-	tt_global_entry = batadv_tt_global_hash_find(bat_priv, addr);
+add_event:
+	batadv_tt_local_event(bat_priv, addr, tt_local->common.flags);
 
-	/* Check whether it is a roaming! */
-	if (tt_global_entry) {
+check_roaming:
+	/* Check whether it is a roaming, but don't do anything if the roaming
+	 * process has already been handled
+	 */
+	if (tt_global && !(tt_global->common.flags & BATADV_TT_CLIENT_ROAM)) {
 		/* These node are probably going to update their tt table */
-		head = &tt_global_entry->orig_list;
+		head = &tt_global->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,
+			batadv_send_roam_adv(bat_priv, tt_global->common.addr,
 					     orig_entry->orig_node);
 		}
 		rcu_read_unlock();
-		/* The global entry has to be marked as ROAMING and
-		 * has to be kept for consistency purpose
-		 */
-		tt_global_entry->common.flags |= BATADV_TT_CLIENT_ROAM;
-		tt_global_entry->roam_at = jiffies;
+		if (roamed_back) {
+			batadv_tt_global_free(bat_priv, tt_global,
+					      "Roaming canceled");
+			tt_global = NULL;
+		} else {
+			/* The global entry has to be marked as ROAMING and
+			 * has to be kept for consistency purpose
+			 */
+			tt_global->common.flags |= BATADV_TT_CLIENT_ROAM;
+			tt_global->roam_at = jiffies;
+		}
 	}
+
 out:
-	if (tt_local_entry)
-		batadv_tt_local_entry_free_ref(tt_local_entry);
-	if (tt_global_entry)
-		batadv_tt_global_entry_free_ref(tt_global_entry);
+	if (tt_local)
+		batadv_tt_local_entry_free_ref(tt_local);
+	if (tt_global)
+		batadv_tt_global_entry_free_ref(tt_global);
 }
 
 static void batadv_tt_realloc_packet_buff(unsigned char **packet_buff,
@@ -502,7 +544,7 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv,
 				const uint8_t *addr, const char *message,
 				bool roaming)
 {
-	struct batadv_tt_local_entry *tt_local_entry = NULL;
+	struct batadv_tt_local_entry *tt_local_entry;
 	uint16_t flags, curr_flags = BATADV_NO_FLAGS;
 
 	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr);
@@ -512,10 +554,28 @@ 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 this global entry addition is due to a roaming, the node has to
+	 * mark the local entry as "roamed" in order to correctly reroute
+	 * packets later
+	 */
+	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);
+	if (!(tt_local_entry->common.flags & BATADV_TT_CLIENT_NEW)) {
+		batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags,
+					    message);
+		goto out;
+	}
+	/* if this client has been added right now, it is possible to
+	 * immediately purge it
+	 */
+	batadv_tt_local_event(bat_priv, tt_local_entry->common.addr,
+			      curr_flags | BATADV_TT_CLIENT_DEL);
+	hlist_del_rcu(&tt_local_entry->common.hash_entry);
+	batadv_tt_local_entry_free_ref(tt_local_entry);
 
 out:
 	if (tt_local_entry)
@@ -724,13 +784,23 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv,
 			 const unsigned char *tt_addr, uint8_t flags,
 			 uint8_t ttvn)
 {
-	struct batadv_tt_global_entry *tt_global_entry = NULL;
+	struct batadv_tt_global_entry *tt_global_entry;
+	struct batadv_tt_local_entry *tt_local_entry;
 	int ret = 0;
 	int hash_added;
 	struct batadv_tt_common_entry *common;
 	uint16_t local_flags;
 
 	tt_global_entry = batadv_tt_global_hash_find(bat_priv, tt_addr);
+	tt_local_entry = batadv_tt_local_hash_find(bat_priv, tt_addr);
+
+	/* if the node already has a local client for this entry, it has to wait
+	 * for a roaming advertisement instead of manually messing up the global
+	 * table
+	 */
+	if ((flags & BATADV_TT_CLIENT_TEMP) && tt_local_entry &&
+	    !(tt_local_entry->common.flags & BATADV_TT_CLIENT_NEW))
+		goto out;
 
 	if (!tt_global_entry) {
 		tt_global_entry = kzalloc(sizeof(*tt_global_entry), GFP_ATOMIC);
@@ -765,19 +835,31 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv,
 			goto out_remove;
 		}
 	} else {
+		common = &tt_global_entry->common;
 		/* If there is already a global entry, we can use this one for
 		 * our processing.
-		 * But if we are trying to add a temporary client we can exit
-		 * directly because the temporary information should never
-		 * override any already known client state (whatever it is)
+		 * But if we are trying to add a temporary client then here are
+		 * two options at this point:
+		 * 1) the global client is not a temporary client: the global
+		 *    client has to be left as it is, temporary information
+		 *    should never override any already known client state
+		 * 2) the global client is a temporary client: purge the
+		 *    originator list and add the new one orig_entry
 		 */
-		if (flags & BATADV_TT_CLIENT_TEMP)
-			goto out;
+		if (flags & BATADV_TT_CLIENT_TEMP) {
+			if (!(common->flags & BATADV_TT_CLIENT_TEMP))
+				goto out;
+			if (batadv_tt_global_entry_has_orig(tt_global_entry,
+							    orig_node))
+				goto out_remove;
+			batadv_tt_global_del_orig_list(tt_global_entry);
+			goto add_orig_entry;
+		}
 
 		/* if the client was temporary added before receiving the first
 		 * OGM announcing it, we have to clear the TEMP flag
 		 */
-		tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_TEMP;
+		common->flags &= ~BATADV_TT_CLIENT_TEMP;
 
 		/* If there is the BATADV_TT_CLIENT_ROAM flag set, there is only
 		 * one originator left in the list and we previously received a
@@ -786,18 +868,19 @@ int batadv_tt_global_add(struct batadv_priv *bat_priv,
 		 * We should first delete the old originator before adding the
 		 * new one.
 		 */
-		if (tt_global_entry->common.flags & BATADV_TT_CLIENT_ROAM) {
+		if (common->flags & BATADV_TT_CLIENT_ROAM) {
 			batadv_tt_global_del_orig_list(tt_global_entry);
-			tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_ROAM;
+			common->flags &= ~BATADV_TT_CLIENT_ROAM;
 			tt_global_entry->roam_at = 0;
 		}
 	}
+add_orig_entry:
 	/* add the new orig_entry (if needed) or update it */
 	batadv_tt_global_orig_entry_add(tt_global_entry, orig_node, ttvn);
 
 	batadv_dbg(BATADV_DBG_TT, bat_priv,
 		   "Creating new global tt entry: %pM (via %pM)\n",
-		   tt_global_entry->common.addr, orig_node->orig);
+		   common->addr, orig_node->orig);
 	ret = 1;
 
 out_remove:
@@ -805,12 +888,20 @@ out_remove:
 	/* remove address from local hash if present */
 	local_flags = batadv_tt_local_remove(bat_priv, tt_addr,
 					     "global tt received",
-					     flags & BATADV_TT_CLIENT_ROAM);
+					     !!(flags & BATADV_TT_CLIENT_ROAM));
 	tt_global_entry->common.flags |= local_flags & BATADV_TT_CLIENT_WIFI;
 
+	if (!(flags & BATADV_TT_CLIENT_ROAM))
+		/* this is a normal global add. Therefore the client is not in a
+		 * roaming state anymore.
+		 */
+		tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_ROAM;
+
 out:
 	if (tt_global_entry)
 		batadv_tt_global_entry_free_ref(tt_global_entry);
+	if (tt_local_entry)
+		batadv_tt_local_entry_free_ref(tt_local_entry);
 	return ret;
 }
 
@@ -928,21 +1019,6 @@ batadv_tt_global_del_orig_entry(struct batadv_priv *bat_priv,
 	spin_unlock_bh(&tt_global_entry->list_lock);
 }
 
-static void
-batadv_tt_global_del_struct(struct batadv_priv *bat_priv,
-			    struct batadv_tt_global_entry *tt_global_entry,
-			    const char *message)
-{
-	batadv_dbg(BATADV_DBG_TT, bat_priv,
-		   "Deleting global tt entry %pM: %s\n",
-		   tt_global_entry->common.addr, message);
-
-	batadv_hash_remove(bat_priv->tt.global_hash, batadv_compare_tt,
-			   batadv_choose_orig, tt_global_entry->common.addr);
-	batadv_tt_global_entry_free_ref(tt_global_entry);
-
-}
-
 /* If the client is to be deleted, we check if it is the last origantor entry
  * within tt_global entry. If yes, we set the BATADV_TT_CLIENT_ROAM flag and the
  * timer, otherwise we simply remove the originator scheduled for deletion.
@@ -991,7 +1067,7 @@ static void batadv_tt_global_del(struct batadv_priv *bat_priv,
 				 const unsigned char *addr,
 				 const char *message, bool roaming)
 {
-	struct batadv_tt_global_entry *tt_global_entry = NULL;
+	struct batadv_tt_global_entry *tt_global_entry;
 	struct batadv_tt_local_entry *local_entry = NULL;
 
 	tt_global_entry = batadv_tt_global_hash_find(bat_priv, addr);
@@ -1003,8 +1079,8 @@ static void batadv_tt_global_del(struct batadv_priv *bat_priv,
 						orig_node, message);
 
 		if (hlist_empty(&tt_global_entry->orig_list))
-			batadv_tt_global_del_struct(bat_priv, tt_global_entry,
-						    message);
+			batadv_tt_global_free(bat_priv, tt_global_entry,
+					      message);
 
 		goto out;
 	}
@@ -1027,7 +1103,7 @@ static void batadv_tt_global_del(struct batadv_priv *bat_priv,
 	if (local_entry) {
 		/* local entry exists, case 2: client roamed to us. */
 		batadv_tt_global_del_orig_list(tt_global_entry);
-		batadv_tt_global_del_struct(bat_priv, tt_global_entry, message);
+		batadv_tt_global_free(bat_priv, tt_global_entry, message);
 	} else
 		/* no local entry exists, case 1: check for roaming */
 		batadv_tt_global_del_roaming(bat_priv, tt_global_entry,
@@ -1206,7 +1282,8 @@ struct batadv_orig_node *batadv_transtable_search(struct batadv_priv *bat_priv,
 
 	if (src && atomic_read(&bat_priv->ap_isolation)) {
 		tt_local_entry = batadv_tt_local_hash_find(bat_priv, src);
-		if (!tt_local_entry)
+		if (!tt_local_entry ||
+		    (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING))
 			goto out;
 	}
 
@@ -1593,7 +1670,7 @@ static bool
 batadv_send_other_tt_response(struct batadv_priv *bat_priv,
 			      struct batadv_tt_query_packet *tt_request)
 {
-	struct batadv_orig_node *req_dst_orig_node = NULL;
+	struct batadv_orig_node *req_dst_orig_node;
 	struct batadv_orig_node *res_dst_orig_node = NULL;
 	struct batadv_neigh_node *neigh_node = NULL;
 	struct batadv_hard_iface *primary_if = NULL;
@@ -1728,7 +1805,7 @@ static bool
 batadv_send_my_tt_response(struct batadv_priv *bat_priv,
 			   struct batadv_tt_query_packet *tt_request)
 {
-	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_orig_node *orig_node;
 	struct batadv_neigh_node *neigh_node = NULL;
 	struct batadv_hard_iface *primary_if = NULL;
 	uint8_t my_ttvn, req_ttvn, ttvn;
@@ -1894,7 +1971,7 @@ static void _batadv_tt_update_changes(struct batadv_priv *bat_priv,
 static void batadv_tt_fill_gtable(struct batadv_priv *bat_priv,
 				  struct batadv_tt_query_packet *tt_response)
 {
-	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_orig_node *orig_node;
 
 	orig_node = batadv_orig_hash_find(bat_priv, tt_response->src);
 	if (!orig_node)
@@ -1936,7 +2013,7 @@ static void batadv_tt_update_changes(struct batadv_priv *bat_priv,
 
 bool batadv_is_my_client(struct batadv_priv *bat_priv, const uint8_t *addr)
 {
-	struct batadv_tt_local_entry *tt_local_entry = NULL;
+	struct batadv_tt_local_entry *tt_local_entry;
 	bool ret = false;
 
 	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr);
@@ -1945,7 +2022,8 @@ 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 +2074,6 @@ 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 +2364,6 @@ 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 +2475,6 @@ 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 +2513,32 @@ 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)

net/batman-adv/translation-table.h

@@ -59,6 +59,8 @@ int batadv_tt_append_diff(struct batadv_priv *bat_priv,
 			  int packet_min_len);
 bool batadv_tt_global_client_is_roaming(struct batadv_priv *bat_priv,
 					uint8_t *addr);
+bool batadv_tt_local_client_is_roaming(struct batadv_priv *bat_priv,
+				       uint8_t *addr);
 bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
 					  struct batadv_orig_node *orig_node,
 					  const unsigned char *addr);

net/batman-adv/types.h

@@ -101,13 +101,6 @@ struct batadv_orig_node {
 	spinlock_t tt_buff_lock; /* protects tt_buff */
 	atomic_t tt_size;
 	bool tt_initialised;
-	/* The tt_poss_change flag is used to detect an ongoing roaming phase.
-	 * If true, then I sent a Roaming_adv to this orig_node and I have to
-	 * inspect every packet directed to it to check whether it is still
-	 * the true destination or not. This flag will be reset to false as
-	 * soon as I receive a new TTVN from this orig_node
-	 */
-	bool tt_poss_change;
 	uint32_t last_real_seqno;
 	uint8_t last_ttl;
 	DECLARE_BITMAP(bcast_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
@@ -212,7 +205,6 @@ struct batadv_priv_tt {
 	atomic_t vn;
 	atomic_t ogm_append_cnt;
 	atomic_t local_changes;
-	bool poss_change;
 	struct list_head changes_list;
 	struct batadv_hashtable *local_hash;
 	struct batadv_hashtable *global_hash;
@@ -303,7 +295,7 @@ struct batadv_priv {
 	struct hlist_head forw_bcast_list;
 	struct batadv_hashtable *orig_hash;
 	spinlock_t forw_bat_list_lock; /* protects forw_bat_list */
-	spinlock_t forw_bcast_list_lock; /* protects  */
+	spinlock_t forw_bcast_list_lock; /* protects forw_bcast_list */
 	struct delayed_work orig_work;
 	struct batadv_hard_iface __rcu *primary_if;  /* rcu protected pointer */
 	struct batadv_algo_ops *bat_algo_ops;
@@ -369,6 +361,7 @@ struct batadv_backbone_gw {
 	struct hlist_node hash_entry;
 	struct batadv_priv *bat_priv;
 	unsigned long lasttime;	/* last time we heard of this backbone gw */
+	atomic_t wait_periods;
 	atomic_t request_sent;
 	atomic_t refcount;
 	struct rcu_head rcu;