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 <linus.luessing@web.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

7 files changed, 167 insertions, 6 deletions

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 58e98c89a68f..8f11b67bc4f4 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -149,6 +149,7 @@ int batadv_mesh_init(struct net_device *soft_iface)
                 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);
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index e099fd67403c..3ba9a18a906c 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -178,11 +178,52 @@ static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
 }
 
 /**
+ * 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)
 {
@@ -190,10 +231,7 @@ 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);
@@ -209,10 +247,83 @@ out:
 }
 
 /**
+ * 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);
+}
diff --git a/net/batman-adv/multicast.h b/net/batman-adv/multicast.h
index 7513e024b807..c029eaca7c44 100644
--- a/net/batman-adv/multicast.h
+++ b/net/batman-adv/multicast.h
@@ -22,8 +22,12 @@
 
 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
 
 static inline void batadv_mcast_mla_update(struct batadv_priv *bat_priv)
@@ -31,11 +35,21 @@ static inline void batadv_mcast_mla_update(struct batadv_priv *bat_priv)
         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;
+}
+
 #endif /* CONFIG_BATMAN_ADV_MCAST */
 
 #endif /* _NET_BATMAN_ADV_MULTICAST_H_ */
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 24a9300b08e0..ffd9dfbd9b0e 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -27,6 +27,7 @@
 #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;
@@ -557,6 +558,8 @@ static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
         }
         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);
 
@@ -672,6 +675,9 @@ struct batadv_orig_node *batadv_orig_node_new(struct batadv_priv *bat_priv,
         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);
diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index 0a381d1174c1..e8c483d2da72 100644
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -145,6 +145,7 @@ enum batadv_bla_claimframe {
  * @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,
@@ -152,6 +153,7 @@ enum batadv_tvlv_type {
         BATADV_TVLV_NC          = 0x03,
         BATADV_TVLV_TT          = 0x04,
         BATADV_TVLV_ROAM        = 0x05,
+        BATADV_TVLV_MCAST       = 0x06,
 };
 
 #pragma pack(2)
@@ -504,4 +506,14 @@ struct batadv_tvlv_roam_adv {
         __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_ */
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 633e9d67d925..8ff47b7a0e04 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -689,6 +689,10 @@ static int batadv_softif_init_late(struct net_device *dev)
 #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);
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index b46117ca5989..96ee0d2b11d9 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -204,6 +204,7 @@ struct batadv_orig_bat_iv {
  * @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
@@ -246,6 +247,9 @@ struct batadv_orig_node {
 #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;
@@ -282,11 +286,14 @@ struct batadv_orig_node {
  * @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),
 };
 
 /**
@@ -612,9 +619,15 @@ struct batadv_priv_dat {
 /**
  * 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