diff --git a/Makefile b/Makefile
index 407cdc4..d7c6fa6 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,8 @@ export CONFIG_BATMAN_ADV_BLA=y
 export CONFIG_BATMAN_ADV_DAT=y
 # B.A.T.M.A.N network coding (catwoman):
 export CONFIG_BATMAN_ADV_NC=n
+# B.A.T.M.A.N. multicast optimizations:
+export CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS=y
 
 PWD:=$(shell pwd)
 KERNELPATH ?= /lib/modules/$(shell uname -r)/build
diff --git a/Makefile.kbuild b/Makefile.kbuild
index 8ddbfe6..d3efe3a 100644
--- a/Makefile.kbuild
+++ b/Makefile.kbuild
@@ -38,3 +38,4 @@ batman-adv-y += soft-interface.o
 batman-adv-y += sysfs.o
 batman-adv-y += translation-table.o
 batman-adv-y += unicast.o
+batman-adv-$(CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS) += multicast.o
diff --git a/compat.c b/compat.c
index 1f3a39d..27df197 100644
--- a/compat.c
+++ b/compat.c
@@ -25,6 +25,27 @@
 #include <linux/version.h>
 #include "main.h"
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 38)
+
+void batadv_for_each_pmc_rcu_init(struct in_device *in_dev,
+				  struct ip_mc_list **pmc)
+{
+	read_lock(&in_dev->mc_list_lock);
+	*pmc = in_dev->mc_list;
+}
+
+bool batadv_for_each_pmc_rcu_check(struct in_device *in_dev,
+				   struct ip_mc_list *pmc)
+{
+	if (pmc == NULL)
+		read_unlock(&in_dev->mc_list_lock);
+
+	return (pmc != NULL);
+}
+
+#endif /* < KERNEL_VERSION(2, 6, 38) */
+
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 0, 0)
 
 void batadv_free_rcu_gw_node(struct rcu_head *rcu)
diff --git a/compat.h b/compat.h
index 8bd4f62..de1556a 100644
--- a/compat.h
+++ b/compat.h
@@ -152,6 +152,24 @@ static inline int batadv_param_set_copystring(const char *val,
 
 #endif /* < KERNEL_VERSION(2, 6, 37) */
 
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 38)
+
+void batadv_for_each_pmc_rcu_init(struct in_device *in_dev,
+				  struct ip_mc_list **pmc);
+bool batadv_for_each_pmc_rcu_check(struct in_device *in_dev,
+				   struct ip_mc_list *pmc);
+
+#undef for_each_pmc_rcu
+#define for_each_pmc_rcu(in_dev, pmc)				\
+	for (batadv_for_each_pmc_rcu_init(in_dev, &pmc);	\
+	     batadv_for_each_pmc_rcu_check(in_dev, pmc);	\
+	     pmc = NULL)					\
+		for (; pmc != NULL; pmc = pmc->next)
+
+#endif /* < KERNEL_VERSION(2, 6, 38) */
+
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
 
 #define kstrtoul strict_strtoul
diff --git a/gen-compat-autoconf.sh b/gen-compat-autoconf.sh
index 78573e4..b56ac29 100755
--- a/gen-compat-autoconf.sh
+++ b/gen-compat-autoconf.sh
@@ -39,6 +39,7 @@ gen_config() {
 gen_config 'CONFIG_BATMAN_ADV_DEBUG' ${CONFIG_BATMAN_ADV_DEBUG:="n"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_BLA' ${CONFIG_BATMAN_ADV_BLA:="y"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_DAT' ${CONFIG_BATMAN_ADV_DAT:="y"} >> "${TMP}"
+gen_config 'CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS' ${CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS:="y"} >> "${TMP}"
 gen_config 'CONFIG_BATMAN_ADV_NC' ${CONFIG_BATMAN_ADV_NC:="n"} >> "${TMP}"
 
 # only regenerate compat-autoconf.h when config was changed
diff --git a/main.c b/main.c
index af89c09..1c82c18 100644
--- a/main.c
+++ b/main.c
@@ -33,6 +33,7 @@
 #include "bridge_loop_avoidance.h"
 #include "distributed-arp-table.h"
 #include "unicast.h"
+#include "multicast.h"
 #include "gateway_common.h"
 #include "hash.h"
 #include "bat_algo.h"
@@ -115,6 +116,9 @@ int batadv_mesh_init(struct net_device *soft_iface)
 	INIT_LIST_HEAD(&bat_priv->tt.changes_list);
 	INIT_LIST_HEAD(&bat_priv->tt.req_list);
 	INIT_LIST_HEAD(&bat_priv->tt.roam_list);
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+	INIT_LIST_HEAD(&bat_priv->mcast.mla_list);
+#endif
 	INIT_HLIST_HEAD(&bat_priv->tvlv.container_list);
 	INIT_HLIST_HEAD(&bat_priv->tvlv.handler_list);
 
@@ -168,6 +172,8 @@ void batadv_mesh_free(struct net_device *soft_iface)
 	batadv_dat_free(bat_priv);
 	batadv_bla_free(bat_priv);
 
+	batadv_mcast_free(bat_priv);
+
 	/* Free the TT and the originator tables only after having terminated
 	 * all the other depending components which may use these structures for
 	 * their purposes.
diff --git a/main.h b/main.h
index 795345f..39c683d 100644
--- a/main.h
+++ b/main.h
@@ -141,6 +141,14 @@ enum batadv_uev_type {
 /* Append 'batman-adv: ' before kernel messages */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#define UINT8_MAX 255
+
+/* identical to the one used in net/ipv4/igmp.c */
+#define for_each_pmc_rcu(in_dev, pmc)				\
+	for (pmc = rcu_dereference(in_dev->mc_list);		\
+	     pmc != NULL;					\
+	     pmc = rcu_dereference(pmc->next_rcu))
+
 /* Kernel headers */
 
 #include <linux/mutex.h>	/* mutex */
@@ -155,6 +163,7 @@ enum batadv_uev_type {
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <net/sock.h>		/* struct sock */
+#include <net/addrconf.h>	/* ipv6 address stuff */
 #include <net/rtnetlink.h>
 #include <linux/jiffies.h>
 #include <linux/seq_file.h>
diff --git a/multicast.c b/multicast.c
new file mode 100644
index 0000000..88bde61
--- /dev/null
+++ b/multicast.c
@@ -0,0 +1,222 @@
+/* Copyright (C) 2013 B.A.T.M.A.N. contributors:
+ *
+ * Linus Lüssing
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+#include "main.h"
+#include "originator.h"
+#include "hard-interface.h"
+#include "translation-table.h"
+
+/* should match batadv_ogm_packet's mcast_num_mla */
+#define BATADV_MLA_MAX UINT8_MAX
+
+/**
+ * batadv_mcast_mla_local_collect - Collects local multicast listeners
+ * @dev:		The device to collect multicast addresses from
+ * @mcast_list:		A list to put found addresses into
+ * @num_mla_max:	The maximum number of items to add
+ *
+ * Collects up to num_mla_max multicast addresses of the local multicast
+ * listeners on the given interface, dev, in the given mcast_list.
+ *
+ * Returns -ENOMEM on memory allocation error or the number of
+ * items added to the mcast_list otherwise.
+ */
+static int batadv_mcast_mla_local_collect(struct net_device *dev,
+					  struct list_head *mcast_list,
+					  int num_mla_max) {
+	struct netdev_hw_addr *mc_list_entry, *new;
+	int num_mla = 0, ret = 0;
+
+	netif_addr_lock_bh(dev);
+	netdev_for_each_mc_addr(mc_list_entry, dev) {
+		if (num_mla >= num_mla_max) {
+			pr_warn("Too many local multicast listener announcements here, just adding %i\n",
+				num_mla_max);
+			break;
+		}
+
+		new = kmalloc(sizeof(struct netdev_hw_addr), GFP_ATOMIC);
+		if (!new) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		memcpy(&new->addr, &mc_list_entry->addr, ETH_ALEN);
+		list_add(&new->list, mcast_list);
+		num_mla++;
+	}
+	netif_addr_unlock_bh(dev);
+
+	return ret < 0 ? ret : num_mla;
+}
+
+/**
+ * batadv_mcast_mla_is_duplicate - Checks whether an address is in a list
+ * @mcast_addr:	The multicast address to check
+ * @mcast_list:	The list with multicast addresses to search in
+ *
+ * Returns true if the given address is already in the given list.
+ * Otherwise returns false.
+ */
+static bool batadv_mcast_mla_is_duplicate(uint8_t *mcast_addr,
+					  struct list_head *mcast_list)
+{
+	struct netdev_hw_addr *mcast_entry;
+
+	list_for_each_entry(mcast_entry, mcast_list, list)
+		if (!memcmp(mcast_entry->addr, mcast_addr, ETH_ALEN))
+			return true;
+
+	return false;
+}
+
+/**
+ * batadv_mcast_mla_collect_free - Frees a list of multicast addresses
+ * @mcast_list:		The list to free
+ *
+ * Removes and frees all items in the given mcast_list.
+ */
+void batadv_mcast_mla_collect_free(struct list_head *mcast_list)
+{
+	struct netdev_hw_addr *mcast_entry, *tmp;
+
+	list_for_each_entry_safe(mcast_entry, tmp, mcast_list, list) {
+		list_del(&mcast_entry->list);
+		kfree(mcast_entry);
+	}
+}
+
+/**
+ * batadv_mcast_mla_tt_clean - Cleans up multicast listener announcements
+ * @bat_priv: the bat priv with all the soft interface information
+ * @mcast_list: A list of addresses which should _not_ be removed
+ *
+ * This method retracts the announcement of any multicast listener from the
+ * translation table except the ones listed in the given mcast_list.
+ */
+static void batadv_mcast_mla_tt_clean(struct batadv_priv *bat_priv,
+				      struct list_head *mcast_list)
+{
+	struct netdev_hw_addr *mcast_entry, *tmp;
+
+	list_for_each_entry_safe(mcast_entry, tmp, &bat_priv->mcast.mla_list,
+				 list) {
+		if (batadv_mcast_mla_is_duplicate(mcast_entry->addr,
+						  mcast_list))
+			continue;
+
+		batadv_tt_local_remove(bat_priv, mcast_entry->addr,
+				       "mcast TT outdated", 0);
+
+		list_del(&mcast_entry->list);
+		kfree(mcast_entry);
+	}
+}
+
+/**
+ * batadv_mcast_mla_tt_add - Adds multicast listener announcements
+ * @soft_iface: the soft interface where MLAs get added to
+ * @mcast_list: A list of addresses which are going to get added
+ *
+ * Adds multicast listener announcements from the given mcast_list to the
+ * translation table if they have not been added yet.
+ */
+static void batadv_mcast_mla_tt_add(struct net_device *soft_iface,
+				    struct list_head *mcast_list)
+{
+	struct netdev_hw_addr *mcast_entry, *tmp;
+	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
+
+	list_for_each_entry_safe(mcast_entry, tmp, mcast_list, list) {
+		if (batadv_mcast_mla_is_duplicate(mcast_entry->addr,
+						  &bat_priv->mcast.mla_list))
+			continue;
+
+		batadv_tt_local_add(soft_iface, mcast_entry->addr,
+				    BATADV_NULL_IFINDEX);
+		list_move_tail(&mcast_entry->list, &bat_priv->mcast.mla_list);
+	}
+}
+
+/**
+ * batadv_mcast_mla_tt_update - Updates the own MLAs
+ * @bat_priv: the bat priv with all the soft interface information
+ *
+ * Updates the own multicast listener announcements in the translation
+ * table. Also takes care of registering or unregistering the multicast
+ * tvlv depending on whether the user activated or deactivated
+ * multicast optimizations.
+ */
+void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv)
+{
+	struct batadv_hard_iface *primary_if;
+	struct net_device *soft_iface;
+	struct list_head mcast_list;
+	int ret;
+	static bool enabled;
+
+	INIT_LIST_HEAD(&mcast_list);
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if)
+		goto out;
+
+	soft_iface = primary_if->soft_iface;
+
+	/* Avoid attaching MLAs, if multicast optimization is disabled
+	 * or there is a bridge on top of our soft interface (TODO) */
+	if (!atomic_read(&bat_priv->mcast_group_awareness) ||
+	    bat_priv->soft_iface->priv_flags & IFF_BRIDGE_PORT) {
+		if (enabled)
+			enabled = false;
+
+		goto update;
+	}
+
+	if (!enabled)
+		enabled = true;
+
+	ret = batadv_mcast_mla_local_collect(soft_iface, &mcast_list,
+					     BATADV_MLA_MAX);
+	if (ret < 0)
+		goto out;
+
+update:
+	batadv_mcast_mla_tt_clean(bat_priv, &mcast_list);
+	batadv_mcast_mla_tt_add(soft_iface, &mcast_list);
+
+out:
+	if (primary_if)
+		batadv_hardif_free_ref(primary_if);
+
+	batadv_mcast_mla_collect_free(&mcast_list);
+}
+
+/**
+ * batadv_mcast_free - Frees the multicast optimizaitons structures
+ * @bat_priv: the bat priv with all the soft interface information
+ */
+void batadv_mcast_free(struct batadv_priv *bat_priv)
+{
+	struct list_head mcast_list;
+
+	INIT_LIST_HEAD(&mcast_list);
+
+	batadv_mcast_mla_tt_clean(bat_priv, &mcast_list);
+}
diff --git a/multicast.h b/multicast.h
new file mode 100644
index 0000000..3b68e3b
--- /dev/null
+++ b/multicast.h
@@ -0,0 +1,43 @@
+/* Copyright (C) 2013 B.A.T.M.A.N. contributors:
+ *
+ * Linus Lüssing
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+#ifndef _NET_BATMAN_ADV_MULTICAST_H_
+#define _NET_BATMAN_ADV_MULTICAST_H_
+
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+
+void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv);
+
+void batadv_mcast_free(struct batadv_priv *bat_priv);
+
+#else
+
+static inline void batadv_mcast_mla_tt_update(struct batadv_priv *bat_priv)
+{
+	return;
+}
+
+static inline void batadv_mcast_free(struct batadv_priv *bat_priv)
+{
+	return;
+}
+
+#endif /* CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS */
+
+#endif /* _NET_BATMAN_ADV_MULTICAST_H_ */
diff --git a/soft-interface.c b/soft-interface.c
index a6ab9e4..b97dfa2 100644
--- a/soft-interface.c
+++ b/soft-interface.c
@@ -457,6 +457,9 @@ 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_OPTIMIZATIONS
+	atomic_set(&bat_priv->mcast_group_awareness, 1);
+#endif
 	atomic_set(&bat_priv->ap_isolation, 0);
 	atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
 	atomic_set(&bat_priv->gw_sel_class, 20);
diff --git a/sysfs.c b/sysfs.c
index cbbb77b..76390d0 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -369,6 +369,9 @@ BATADV_ATTR_SIF_UINT(gw_sel_class, S_IRUGO | S_IWUSR, 1, BATADV_TQ_MAX_VALUE,
 		     batadv_post_gw_deselect);
 static BATADV_ATTR(gw_bandwidth, S_IRUGO | S_IWUSR, batadv_show_gw_bwidth,
 		   batadv_store_gw_bwidth);
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+BATADV_ATTR_SIF_BOOL(mcast_group_awareness, S_IRUGO | S_IWUSR, NULL);
+#endif
 #ifdef CONFIG_BATMAN_ADV_DEBUG
 BATADV_ATTR_SIF_UINT(log_level, S_IRUGO | S_IWUSR, 0, BATADV_DBG_ALL, NULL);
 #endif
@@ -386,6 +389,9 @@ static struct batadv_attribute *batadv_mesh_attrs[] = {
 #ifdef CONFIG_BATMAN_ADV_DAT
 	&batadv_attr_distributed_arp_table,
 #endif
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+	&batadv_attr_mcast_group_awareness,
+#endif
 	&batadv_attr_fragmentation,
 	&batadv_attr_ap_isolation,
 	&batadv_attr_routing_algo,
diff --git a/translation-table.c b/translation-table.c
index df6b5cd..37e7d47 100644
--- a/translation-table.c
+++ b/translation-table.c
@@ -26,6 +26,7 @@
 #include "originator.h"
 #include "routing.h"
 #include "bridge_loop_avoidance.h"
+#include "multicast.h"
 
 #include <linux/crc32c.h>
 
@@ -281,7 +282,8 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
 	bool roamed_back = false;
 
 	tt_local = batadv_tt_local_hash_find(bat_priv, addr);
-	tt_global = batadv_tt_global_hash_find(bat_priv, addr);
+	tt_global = is_multicast_ether_addr(addr) ? NULL :
+		    batadv_tt_global_hash_find(bat_priv, addr);
 
 	if (tt_local) {
 		tt_local->last_seen = jiffies;
@@ -332,8 +334,10 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
 	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))
+	/* the batman interface mac and multicast addresses should never be
+	 * purged */
+	if (batadv_compare_eth(addr, soft_iface->dev_addr) ||
+	    is_multicast_ether_addr(addr))
 		tt_local->common.flags |= BATADV_TT_CLIENT_NOPURGE;
 
 	hash_added = batadv_hash_add(bat_priv->tt.local_hash, batadv_compare_tt,
@@ -919,6 +923,10 @@ add_orig_entry:
 	ret = true;
 
 out_remove:
+	/* Do not remove multicast addresses from the local hash on
+	 * global additions */
+	if (is_multicast_ether_addr(tt_addr))
+		goto out;
 
 	/* remove address from local hash if present */
 	local_flags = batadv_tt_local_remove(bat_priv, tt_addr,
@@ -2346,6 +2354,9 @@ void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
 {
 	uint16_t changed_num = 0;
 
+	/* Update multicast addresses in local translation table */
+	batadv_mcast_mla_tt_update(bat_priv);
+
 	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);
diff --git a/types.h b/types.h
index c84f5cc..5d73a75 100644
--- a/types.h
+++ b/types.h
@@ -473,6 +473,12 @@ struct batadv_priv_dat {
 };
 #endif
 
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+struct batadv_priv_mcast {
+	struct list_head mla_list;
+};
+#endif
+
 /**
  * struct batadv_priv_nc - per mesh interface network coding private data
  * @work: work queue callback item for cleanup
@@ -561,6 +567,9 @@ struct batadv_priv {
 #ifdef CONFIG_BATMAN_ADV_DAT
 	atomic_t distributed_arp_table;
 #endif
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+	atomic_t mcast_group_awareness;
+#endif
 	atomic_t gw_mode;
 	atomic_t gw_sel_class;
 	atomic_t orig_interval;
@@ -595,6 +604,9 @@ struct batadv_priv {
 #ifdef CONFIG_BATMAN_ADV_DAT
 	struct batadv_priv_dat dat;
 #endif
+#ifdef CONFIG_BATMAN_ADV_MCAST_OPTIMIZATIONS
+	struct batadv_priv_mcast mcast;
+#endif
 #ifdef CONFIG_BATMAN_ADV_NC
 	atomic_t network_coding;
 	struct batadv_priv_nc nc;
