batman-adv: Announce new capability via multicast TVLV

If the soft interface of a node is not part of a bridge then a node
announces a new multicast TVLV: The existence of this TVLV
signalizes that this node is announcing all of its multicast listeners
via the translation table infrastructure.

Signed-off-by: Linus Lüssing <[e-mail]>
Signed-off-by: Marek Lindner <[e-mail]>
Signed-off-by: Antonio Quartulli <[e-mail]>

net/batman-adv/main.c

···
 		goto err;
 
 	batadv_gw_init(bat_priv);
+	batadv_mcast_init(bat_priv);
 
 	atomic_set(&bat_priv->gw.reselect, 0);
 	atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);

net/batman-adv/multicast.c

···
 }
 
 /**
+ * batadv_mcast_mla_tvlv_update - update multicast tvlv
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Updates the own multicast tvlv with our current multicast related settings,
+ * capabilities and inabilities.
+ *
+ * Returns true if the tvlv container is registered afterwards. Otherwise
+ * returns false.
+ */
+static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
+{
+	struct batadv_tvlv_mcast_data mcast_data;
+
+	mcast_data.flags = BATADV_NO_FLAGS;
+	memset(mcast_data.reserved, 0, sizeof(mcast_data.reserved));
+
+	/* Avoid attaching MLAs, if there is a bridge on top of our soft
+	 * interface, we don't support that yet (TODO)
+	 */
+	if (batadv_mcast_has_bridge(bat_priv)) {
+		if (bat_priv->mcast.enabled) {
+			batadv_tvlv_container_unregister(bat_priv,
+							 BATADV_TVLV_MCAST, 1);
+			bat_priv->mcast.enabled = false;
+		}
+
+		return false;
+	}
+
+	if (!bat_priv->mcast.enabled ||
+	    mcast_data.flags != bat_priv->mcast.flags) {
+		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_MCAST, 1,
+					       &mcast_data, sizeof(mcast_data));
+		bat_priv->mcast.flags = mcast_data.flags;
+		bat_priv->mcast.enabled = true;
+	}
+
+	return true;
+}
+
+/**
  * batadv_mcast_mla_update - update the own MLAs
  * @bat_priv: the bat priv with all the soft interface information
  *
- * Update the own multicast listener announcements in the translation
- * table.
+ * Updates the own multicast listener announcements in the translation
+ * table as well as the own, announced multicast tvlv container.
  */
 void batadv_mcast_mla_update(struct batadv_priv *bat_priv)
 {
···
 	struct hlist_head mcast_list = HLIST_HEAD_INIT;
 	int ret;
 
-	/* Avoid attaching MLAs, if there is a bridge on top of our soft
-	 * interface, we don't support that yet (TODO)
-	 */
-	if (batadv_mcast_has_bridge(bat_priv))
+	if (!batadv_mcast_mla_tvlv_update(bat_priv))
 		goto update;
 
 	ret = batadv_mcast_mla_softif_get(soft_iface, &mcast_list);
···
 }
 
 /**
+ * batadv_mcast_tvlv_ogm_handler_v1 - process incoming multicast tvlv container
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig: the orig_node of the ogm
+ * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
+ * @tvlv_value: tvlv buffer containing the multicast data
+ * @tvlv_value_len: tvlv buffer length
+ */
+static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
+					     struct batadv_orig_node *orig,
+					     uint8_t flags,
+					     void *tvlv_value,
+					     uint16_t tvlv_value_len)
+{
+	bool orig_mcast_enabled = !(flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
+	uint8_t mcast_flags = BATADV_NO_FLAGS;
+	bool orig_initialized;
+
+	orig_initialized = orig->capa_initialized & BATADV_ORIG_CAPA_HAS_MCAST;
+
+	/* If mcast support is turned on decrease the disabled mcast node
+	 * counter only if we had increased it for this node before. If this
+	 * is a completely new orig_node no need to decrease the counter.
+	 */
+	if (orig_mcast_enabled &&
+	    !(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST)) {
+		if (orig_initialized)
+			atomic_dec(&bat_priv->mcast.num_disabled);
+		orig->capabilities |= BATADV_ORIG_CAPA_HAS_MCAST;
+	/* If mcast support is being switched off increase the disabled
+	 * mcast node counter.
+	 */
+	} else if (!orig_mcast_enabled &&
+		   orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST) {
+		atomic_inc(&bat_priv->mcast.num_disabled);
+		orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_MCAST;
+	}
+
+	orig->capa_initialized |= BATADV_ORIG_CAPA_HAS_MCAST;
+
+	if (orig_mcast_enabled && tvlv_value &&
+	    (tvlv_value_len >= sizeof(mcast_flags)))
+		mcast_flags = *(uint8_t *)tvlv_value;
+
+	orig->mcast_flags = mcast_flags;
+}
+
+/**
+ * batadv_mcast_init - initialize the multicast optimizations structures
+ * @bat_priv: the bat priv with all the soft interface information
+ */
+void batadv_mcast_init(struct batadv_priv *bat_priv)
+{
+	batadv_tvlv_handler_register(bat_priv, batadv_mcast_tvlv_ogm_handler_v1,
+				     NULL, BATADV_TVLV_MCAST, 1,
+				     BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
+}
+
+/**
  * batadv_mcast_free - free the multicast optimizations structures
  * @bat_priv: the bat priv with all the soft interface information
  */
 void batadv_mcast_free(struct batadv_priv *bat_priv)
 {
+	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_MCAST, 1);
+	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_MCAST, 1);
+
 	batadv_mcast_mla_tt_retract(bat_priv, NULL);
+}
+
+/**
+ * batadv_mcast_purge_orig - reset originator global mcast state modifications
+ * @orig: the originator which is going to get purged
+ */
+void batadv_mcast_purge_orig(struct batadv_orig_node *orig)
+{
+	struct batadv_priv *bat_priv = orig->bat_priv;
+
+	if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST))
+		atomic_dec(&bat_priv->mcast.num_disabled);
 }

net/batman-adv/multicast.h

···
 
 void batadv_mcast_mla_update(struct batadv_priv *bat_priv);
 
+void batadv_mcast_init(struct batadv_priv *bat_priv);
+
 void batadv_mcast_free(struct batadv_priv *bat_priv);
+
+void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node);
 
 #else
 
···
 	return;
 }
 
+static inline int batadv_mcast_init(struct batadv_priv *bat_priv)
+{
+	return 0;
+}
+
 static inline void batadv_mcast_free(struct batadv_priv *bat_priv)
+{
+	return;
+}
+
+static inline void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node)
 {
 	return;
 }

net/batman-adv/originator.c

···
 #include "bridge_loop_avoidance.h"
 #include "network-coding.h"
 #include "fragmentation.h"
+#include "multicast.h"
 
 /* hash class keys */
 static struct lock_class_key batadv_orig_hash_lock_class_key;
···
 	}
 	spin_unlock_bh(&orig_node->neigh_list_lock);
 
+	batadv_mcast_purge_orig(orig_node);
+
 	/* Free nc_nodes */
 	batadv_nc_purge_orig(orig_node->bat_priv, orig_node, NULL);
 
···
 	orig_node->tt_buff_len = 0;
 	reset_time = jiffies - 1 - msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
 	orig_node->bcast_seqno_reset = reset_time;
+#ifdef CONFIG_BATMAN_ADV_MCAST
+	orig_node->mcast_flags = BATADV_NO_FLAGS;
+#endif
 
 	/* create a vlan object for the "untagged" LAN */
 	vlan = batadv_orig_node_vlan_new(orig_node, BATADV_NO_FLAGS);

net/batman-adv/packet.h

···
  * @BATADV_TVLV_NC: network coding tvlv
  * @BATADV_TVLV_TT: translation table tvlv
  * @BATADV_TVLV_ROAM: roaming advertisement tvlv
+ * @BATADV_TVLV_MCAST: multicast capability tvlv
  */
 enum batadv_tvlv_type {
 	BATADV_TVLV_GW		= 0x01,
···
 	BATADV_TVLV_NC		= 0x03,
 	BATADV_TVLV_TT		= 0x04,
 	BATADV_TVLV_ROAM	= 0x05,
+	BATADV_TVLV_MCAST	= 0x06,
 };
 
 #pragma pack(2)
···
 struct batadv_tvlv_roam_adv {
 	uint8_t  client[ETH_ALEN];
 	__be16 vid;
+};
+
+/**
+ * struct batadv_tvlv_mcast_data - payload of a multicast tvlv
+ * @flags: multicast flags announced by the orig node
+ * @reserved: reserved field
+ */
+struct batadv_tvlv_mcast_data {
+	uint8_t	flags;
+	uint8_t reserved[3];
 };
 
 #endif /* _NET_BATMAN_ADV_PACKET_H_ */

net/batman-adv/soft-interface.c

···
 #ifdef CONFIG_BATMAN_ADV_DAT
 	atomic_set(&bat_priv->distributed_arp_table, 1);
 #endif
+#ifdef CONFIG_BATMAN_ADV_MCAST
+	bat_priv->mcast.flags = BATADV_NO_FLAGS;
+	atomic_set(&bat_priv->mcast.num_disabled, 0);
+#endif
 	atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
 	atomic_set(&bat_priv->gw_sel_class, 20);
 	atomic_set(&bat_priv->gw.bandwidth_down, 100);

net/batman-adv/types.h

···
  * @batadv_dat_addr_t:  address of the orig node in the distributed hash
  * @last_seen: time when last packet from this node was received
  * @bcast_seqno_reset: time when the broadcast seqno window was reset
+ * @mcast_flags: multicast flags announced by the orig node
  * @capabilities: announced capabilities of this originator
  * @capa_initialized: bitfield to remember whether a capability was initialized
  * @last_ttvn: last seen translation table version number
···
 #endif
 	unsigned long last_seen;
 	unsigned long bcast_seqno_reset;
+#ifdef CONFIG_BATMAN_ADV_MCAST
+	uint8_t mcast_flags;
+#endif
 	uint8_t capabilities;
 	uint8_t capa_initialized;
 	atomic_t last_ttvn;
···
  * @BATADV_ORIG_CAPA_HAS_DAT: orig node has distributed arp table enabled
  * @BATADV_ORIG_CAPA_HAS_NC: orig node has network coding enabled
  * @BATADV_ORIG_CAPA_HAS_TT: orig node has tt capability
+ * @BATADV_ORIG_CAPA_HAS_MCAST: orig node has some multicast capability
+ *  (= orig node announces a tvlv of type BATADV_TVLV_MCAST)
  */
 enum batadv_orig_capabilities {
 	BATADV_ORIG_CAPA_HAS_DAT = BIT(0),
 	BATADV_ORIG_CAPA_HAS_NC = BIT(1),
 	BATADV_ORIG_CAPA_HAS_TT = BIT(2),
+	BATADV_ORIG_CAPA_HAS_MCAST = BIT(3),
 };
 
 /**
···
 /**
  * struct batadv_priv_mcast - per mesh interface mcast data
  * @mla_list: list of multicast addresses we are currently announcing via TT
+ * @flags: the flags we have last sent in our mcast tvlv
+ * @enabled: whether the multicast tvlv is currently enabled
+ * @num_disabled: number of nodes that have no mcast tvlv
  */
 struct batadv_priv_mcast {
 	struct hlist_head mla_list;
+	uint8_t flags;
+	bool enabled;
+	atomic_t num_disabled;
 };
 #endif