/* Copyright (C) 2014-2017  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, see <http://www.gnu.org/licenses/>.
   */

  #include "multicast.h"

  #include "main.h"
  
  #include <linux/atomic.h>

  #include <linux/bitops.h>

  #include <linux/bug.h>

  #include <linux/byteorder/generic.h>
  #include <linux/errno.h>
  #include <linux/etherdevice.h>
  #include <linux/fs.h>

  #include <linux/icmpv6.h>

  #include <linux/if_bridge.h>

  #include <linux/if_ether.h>

  #include <linux/igmp.h>

  #include <linux/in.h>

  #include <linux/in6.h>

  #include <linux/ip.h>
  #include <linux/ipv6.h>

  #include <linux/jiffies.h>

  #include <linux/kernel.h>

  #include <linux/kref.h>

  #include <linux/list.h>

  #include <linux/lockdep.h>

  #include <linux/netdevice.h>

  #include <linux/printk.h>

  #include <linux/rculist.h>
  #include <linux/rcupdate.h>

  #include <linux/seq_file.h>

  #include <linux/skbuff.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/stddef.h>
  #include <linux/string.h>
  #include <linux/types.h>

  #include <linux/workqueue.h>

  #include <net/addrconf.h>

  #include <net/if_inet6.h>
  #include <net/ip.h>

  #include <net/ipv6.h>

  #include "hard-interface.h"
  #include "hash.h"

  #include "log.h"

  #include "packet.h"

  #include "translation-table.h"

  #include "tvlv.h"

  static void batadv_mcast_mla_update(struct work_struct *work);
  
  /**
   * batadv_mcast_start_timer - schedule the multicast periodic worker
   * @bat_priv: the bat priv with all the soft interface information
   */
  static void batadv_mcast_start_timer(struct batadv_priv *bat_priv)
  {
  	queue_delayed_work(batadv_event_workqueue, &bat_priv->mcast.work,
  			   msecs_to_jiffies(BATADV_MCAST_WORK_PERIOD));
  }

  /**

   * batadv_mcast_get_bridge - get the bridge on top of the softif if it exists
   * @soft_iface: netdev struct of the mesh interface
   *
   * If the given soft interface has a bridge on top then the refcount
   * of the according net device is increased.
   *
   * Return: NULL if no such bridge exists. Otherwise the net device of the
   * bridge.
   */
  static struct net_device *batadv_mcast_get_bridge(struct net_device *soft_iface)
  {
  	struct net_device *upper = soft_iface;
  
  	rcu_read_lock();
  	do {
  		upper = netdev_master_upper_dev_get_rcu(upper);
  	} while (upper && !(upper->priv_flags & IFF_EBRIDGE));
  
  	if (upper)
  		dev_hold(upper);
  	rcu_read_unlock();
  
  	return upper;
  }
  
  /**

   * batadv_mcast_mla_softif_get - get softif multicast listeners
   * @dev: the device to collect multicast addresses from
   * @mcast_list: a list to put found addresses into
   *

   * Collects multicast addresses of multicast listeners residing
   * on this kernel on the given soft interface, dev, in
   * the given mcast_list. In general, multicast listeners provided by
   * your multicast receiving applications run directly on this node.
   *
   * If there is a bridge interface on top of dev, collects from that one
   * instead. Just like with IP addresses and routes, multicast listeners
   * will(/should) register to the bridge interface instead of an
   * enslaved bat0.

   *

   * Return: -ENOMEM on memory allocation error or the number of

   * items added to the mcast_list otherwise.
   */
  static int batadv_mcast_mla_softif_get(struct net_device *dev,
  				       struct hlist_head *mcast_list)
  {

  	struct net_device *bridge = batadv_mcast_get_bridge(dev);

  	struct netdev_hw_addr *mc_list_entry;
  	struct batadv_hw_addr *new;
  	int ret = 0;

  	netif_addr_lock_bh(bridge ? bridge : dev);
  	netdev_for_each_mc_addr(mc_list_entry, bridge ? bridge : dev) {

  		new = kmalloc(sizeof(*new), GFP_ATOMIC);
  		if (!new) {
  			ret = -ENOMEM;
  			break;
  		}
  
  		ether_addr_copy(new->addr, mc_list_entry->addr);
  		hlist_add_head(&new->list, mcast_list);
  		ret++;
  	}

  	netif_addr_unlock_bh(bridge ? bridge : dev);
  
  	if (bridge)
  		dev_put(bridge);

  
  	return ret;
  }
  
  /**
   * batadv_mcast_mla_is_duplicate - check whether an address is in a list
   * @mcast_addr: the multicast address to check
   * @mcast_list: the list with multicast addresses to search in
   *

   * Return: true if the given address is already in the given list.

   * Otherwise returns false.
   */

  static bool batadv_mcast_mla_is_duplicate(u8 *mcast_addr,

  					  struct hlist_head *mcast_list)
  {
  	struct batadv_hw_addr *mcast_entry;
  
  	hlist_for_each_entry(mcast_entry, mcast_list, list)
  		if (batadv_compare_eth(mcast_entry->addr, mcast_addr))
  			return true;
  
  	return false;
  }
  
  /**

   * batadv_mcast_mla_br_addr_cpy - copy a bridge multicast address
   * @dst: destination to write to - a multicast MAC address
   * @src: source to read from - a multicast IP address
   *
   * Converts a given multicast IPv4/IPv6 address from a bridge
   * to its matching multicast MAC address and copies it into the given
   * destination buffer.
   *
   * Caller needs to make sure the destination buffer can hold
   * at least ETH_ALEN bytes.
   */
  static void batadv_mcast_mla_br_addr_cpy(char *dst, const struct br_ip *src)
  {
  	if (src->proto == htons(ETH_P_IP))
  		ip_eth_mc_map(src->u.ip4, dst);
  #if IS_ENABLED(CONFIG_IPV6)
  	else if (src->proto == htons(ETH_P_IPV6))
  		ipv6_eth_mc_map(&src->u.ip6, dst);
  #endif
  	else
  		eth_zero_addr(dst);
  }
  
  /**
   * batadv_mcast_mla_bridge_get - get bridged-in multicast listeners
   * @dev: a bridge slave whose bridge to collect multicast addresses from
   * @mcast_list: a list to put found addresses into
   *
   * Collects multicast addresses of multicast listeners residing
   * on foreign, non-mesh devices which we gave access to our mesh via
   * a bridge on top of the given soft interface, dev, in the given
   * mcast_list.
   *
   * Return: -ENOMEM on memory allocation error or the number of
   * items added to the mcast_list otherwise.
   */
  static int batadv_mcast_mla_bridge_get(struct net_device *dev,
  				       struct hlist_head *mcast_list)
  {
  	struct list_head bridge_mcast_list = LIST_HEAD_INIT(bridge_mcast_list);
  	struct br_ip_list *br_ip_entry, *tmp;
  	struct batadv_hw_addr *new;
  	u8 mcast_addr[ETH_ALEN];
  	int ret;
  
  	/* we don't need to detect these devices/listeners, the IGMP/MLD
  	 * snooping code of the Linux bridge already does that for us
  	 */
  	ret = br_multicast_list_adjacent(dev, &bridge_mcast_list);
  	if (ret < 0)
  		goto out;
  
  	list_for_each_entry(br_ip_entry, &bridge_mcast_list, list) {
  		batadv_mcast_mla_br_addr_cpy(mcast_addr, &br_ip_entry->addr);
  		if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
  			continue;
  
  		new = kmalloc(sizeof(*new), GFP_ATOMIC);
  		if (!new) {
  			ret = -ENOMEM;
  			break;
  		}
  
  		ether_addr_copy(new->addr, mcast_addr);
  		hlist_add_head(&new->list, mcast_list);
  	}
  
  out:
  	list_for_each_entry_safe(br_ip_entry, tmp, &bridge_mcast_list, list) {
  		list_del(&br_ip_entry->list);
  		kfree(br_ip_entry);
  	}
  
  	return ret;
  }
  
  /**

   * batadv_mcast_mla_list_free - free a list of multicast addresses
   * @mcast_list: the list to free
   *
   * Removes and frees all items in the given mcast_list.
   */

  static void batadv_mcast_mla_list_free(struct hlist_head *mcast_list)

  {
  	struct batadv_hw_addr *mcast_entry;
  	struct hlist_node *tmp;
  
  	hlist_for_each_entry_safe(mcast_entry, tmp, mcast_list, list) {
  		hlist_del(&mcast_entry->list);
  		kfree(mcast_entry);
  	}
  }
  
  /**
   * batadv_mcast_mla_tt_retract - clean 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
   *
   * Retracts the announcement of any multicast listener from the
   * translation table except the ones listed in the given mcast_list.
   *
   * If mcast_list is NULL then all are retracted.

   *
   * Do not call outside of the mcast worker! (or cancel mcast worker first)

   */
  static void batadv_mcast_mla_tt_retract(struct batadv_priv *bat_priv,
  					struct hlist_head *mcast_list)
  {
  	struct batadv_hw_addr *mcast_entry;
  	struct hlist_node *tmp;

  	WARN_ON(delayed_work_pending(&bat_priv->mcast.work));

  	hlist_for_each_entry_safe(mcast_entry, tmp, &bat_priv->mcast.mla_list,
  				  list) {
  		if (mcast_list &&
  		    batadv_mcast_mla_is_duplicate(mcast_entry->addr,
  						  mcast_list))
  			continue;
  
  		batadv_tt_local_remove(bat_priv, mcast_entry->addr,
  				       BATADV_NO_FLAGS,
  				       "mcast TT outdated", false);
  
  		hlist_del(&mcast_entry->list);
  		kfree(mcast_entry);
  	}
  }
  
  /**
   * batadv_mcast_mla_tt_add - add multicast listener announcements
   * @bat_priv: the bat priv with all the soft interface information
   * @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.

   *
   * Do not call outside of the mcast worker! (or cancel mcast worker first)

   */
  static void batadv_mcast_mla_tt_add(struct batadv_priv *bat_priv,
  				    struct hlist_head *mcast_list)
  {
  	struct batadv_hw_addr *mcast_entry;
  	struct hlist_node *tmp;

  	WARN_ON(delayed_work_pending(&bat_priv->mcast.work));

  	if (!mcast_list)
  		return;
  
  	hlist_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;
  
  		if (!batadv_tt_local_add(bat_priv->soft_iface,
  					 mcast_entry->addr, BATADV_NO_FLAGS,
  					 BATADV_NULL_IFINDEX, BATADV_NO_MARK))
  			continue;
  
  		hlist_del(&mcast_entry->list);
  		hlist_add_head(&mcast_entry->list, &bat_priv->mcast.mla_list);
  	}
  }
  
  /**
   * batadv_mcast_has_bridge - check whether the soft-iface is bridged
   * @bat_priv: the bat priv with all the soft interface information
   *

   * Checks whether there is a bridge on top of our soft interface.
   *
   * Return: true if there is a bridge, false otherwise.

   */
  static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
  {
  	struct net_device *upper = bat_priv->soft_iface;
  
  	rcu_read_lock();
  	do {
  		upper = netdev_master_upper_dev_get_rcu(upper);
  	} while (upper && !(upper->priv_flags & IFF_EBRIDGE));
  	rcu_read_unlock();
  
  	return upper;
  }
  
  /**

   * batadv_mcast_querier_log - debug output regarding the querier status on link
   * @bat_priv: the bat priv with all the soft interface information
   * @str_proto: a string for the querier protocol (e.g. "IGMP" or "MLD")
   * @old_state: the previous querier state on our link
   * @new_state: the new querier state on our link
   *
   * Outputs debug messages to the logging facility with log level 'mcast'
   * regarding changes to the querier status on the link which are relevant
   * to our multicast optimizations.
   *
   * Usually this is about whether a querier appeared or vanished in
   * our mesh or whether the querier is in the suboptimal position of being
   * behind our local bridge segment: Snooping switches will directly
   * forward listener reports to the querier, therefore batman-adv and
   * the bridge will potentially not see these listeners - the querier is
   * potentially shadowing listeners from us then.
   *
   * This is only interesting for nodes with a bridge on top of their
   * soft interface.
   */
  static void
  batadv_mcast_querier_log(struct batadv_priv *bat_priv, char *str_proto,
  			 struct batadv_mcast_querier_state *old_state,
  			 struct batadv_mcast_querier_state *new_state)
  {
  	if (!old_state->exists && new_state->exists)
  		batadv_info(bat_priv->soft_iface, "%s Querier appeared
  ",
  			    str_proto);
  	else if (old_state->exists && !new_state->exists)
  		batadv_info(bat_priv->soft_iface,
  			    "%s Querier disappeared - multicast optimizations disabled
  ",
  			    str_proto);
  	else if (!bat_priv->mcast.bridged && !new_state->exists)
  		batadv_info(bat_priv->soft_iface,
  			    "No %s Querier present - multicast optimizations disabled
  ",
  			    str_proto);
  
  	if (new_state->exists) {
  		if ((!old_state->shadowing && new_state->shadowing) ||
  		    (!old_state->exists && new_state->shadowing))
  			batadv_dbg(BATADV_DBG_MCAST, bat_priv,
  				   "%s Querier is behind our bridged segment: Might shadow listeners
  ",
  				   str_proto);
  		else if (old_state->shadowing && !new_state->shadowing)
  			batadv_dbg(BATADV_DBG_MCAST, bat_priv,
  				   "%s Querier is not behind our bridged segment
  ",
  				   str_proto);
  	}
  }
  
  /**
   * batadv_mcast_bridge_log - debug output for topology changes in bridged setups
   * @bat_priv: the bat priv with all the soft interface information
   * @bridged: a flag about whether the soft interface is currently bridged or not
   * @querier_ipv4: (maybe) new status of a potential, selected IGMP querier
   * @querier_ipv6: (maybe) new status of a potential, selected MLD querier
   *
   * If no bridges are ever used on this node, then this function does nothing.
   *
   * Otherwise this function outputs debug information to the 'mcast' log level
   * which might be relevant to our multicast optimizations.
   *
   * More precisely, it outputs information when a bridge interface is added or
   * removed from a soft interface. And when a bridge is present, it further
   * outputs information about the querier state which is relevant for the
   * multicast flags this node is going to set.
   */
  static void
  batadv_mcast_bridge_log(struct batadv_priv *bat_priv, bool bridged,
  			struct batadv_mcast_querier_state *querier_ipv4,
  			struct batadv_mcast_querier_state *querier_ipv6)
  {
  	if (!bat_priv->mcast.bridged && bridged)
  		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
  			   "Bridge added: Setting Unsnoopables(U)-flag
  ");
  	else if (bat_priv->mcast.bridged && !bridged)
  		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
  			   "Bridge removed: Unsetting Unsnoopables(U)-flag
  ");
  
  	if (bridged) {
  		batadv_mcast_querier_log(bat_priv, "IGMP",
  					 &bat_priv->mcast.querier_ipv4,
  					 querier_ipv4);
  		batadv_mcast_querier_log(bat_priv, "MLD",
  					 &bat_priv->mcast.querier_ipv6,
  					 querier_ipv6);
  	}
  }
  
  /**
   * batadv_mcast_flags_logs - output debug information about mcast flag changes
   * @bat_priv: the bat priv with all the soft interface information
   * @flags: flags indicating the new multicast state
   *
   * Whenever the multicast flags this nodes announces changes (@mcast_flags vs.
   * bat_priv->mcast.flags), this notifies userspace via the 'mcast' log level.
   */
  static void batadv_mcast_flags_log(struct batadv_priv *bat_priv, u8 flags)
  {
  	u8 old_flags = bat_priv->mcast.flags;
  	char str_old_flags[] = "[...]";
  
  	sprintf(str_old_flags, "[%c%c%c]",
  		(old_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) ? 'U' : '.',
  		(old_flags & BATADV_MCAST_WANT_ALL_IPV4) ? '4' : '.',
  		(old_flags & BATADV_MCAST_WANT_ALL_IPV6) ? '6' : '.');
  
  	batadv_dbg(BATADV_DBG_MCAST, bat_priv,
  		   "Changing multicast flags from '%s' to '[%c%c%c]'
  ",
  		   bat_priv->mcast.enabled ? str_old_flags : "<undefined>",
  		   (flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) ? 'U' : '.',
  		   (flags & BATADV_MCAST_WANT_ALL_IPV4) ? '4' : '.',
  		   (flags & BATADV_MCAST_WANT_ALL_IPV6) ? '6' : '.');
  }
  
  /**

   * 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.
   *

   * Return: false if we want all IPv4 && IPv6 multicast traffic and true
   * otherwise.

   */
  static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
  {
  	struct batadv_tvlv_mcast_data mcast_data;

  	struct batadv_mcast_querier_state querier4 = {false, false};
  	struct batadv_mcast_querier_state querier6 = {false, false};
  	struct net_device *dev = bat_priv->soft_iface;

  	bool bridged;

  
  	mcast_data.flags = BATADV_NO_FLAGS;
  	memset(mcast_data.reserved, 0, sizeof(mcast_data.reserved));

  	bridged = batadv_mcast_has_bridge(bat_priv);
  	if (!bridged)

  		goto update;

  	if (!IS_ENABLED(CONFIG_BRIDGE_IGMP_SNOOPING))
  		pr_warn_once("No bridge IGMP snooping compiled - multicast optimizations disabled
  ");

  
  	querier4.exists = br_multicast_has_querier_anywhere(dev, ETH_P_IP);
  	querier4.shadowing = br_multicast_has_querier_adjacent(dev, ETH_P_IP);
  
  	querier6.exists = br_multicast_has_querier_anywhere(dev, ETH_P_IPV6);
  	querier6.shadowing = br_multicast_has_querier_adjacent(dev, ETH_P_IPV6);
  
  	mcast_data.flags |= BATADV_MCAST_WANT_ALL_UNSNOOPABLES;
  
  	/* 1) If no querier exists at all, then multicast listeners on
  	 *    our local TT clients behind the bridge will keep silent.
  	 * 2) If the selected querier is on one of our local TT clients,
  	 *    behind the bridge, then this querier might shadow multicast
  	 *    listeners on our local TT clients, behind this bridge.
  	 *
  	 * In both cases, we will signalize other batman nodes that
  	 * we need all multicast traffic of the according protocol.

  	 */

  	if (!querier4.exists || querier4.shadowing)
  		mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV4;

  	if (!querier6.exists || querier6.shadowing)
  		mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV6;

  update:

  	batadv_mcast_bridge_log(bat_priv, bridged, &querier4, &querier6);
  
  	bat_priv->mcast.querier_ipv4.exists = querier4.exists;
  	bat_priv->mcast.querier_ipv4.shadowing = querier4.shadowing;
  
  	bat_priv->mcast.querier_ipv6.exists = querier6.exists;
  	bat_priv->mcast.querier_ipv6.shadowing = querier6.shadowing;
  
  	bat_priv->mcast.bridged = bridged;

  	if (!bat_priv->mcast.enabled ||
  	    mcast_data.flags != bat_priv->mcast.flags) {

  		batadv_mcast_flags_log(bat_priv, mcast_data.flags);

  		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_MCAST, 2,

  					       &mcast_data, sizeof(mcast_data));
  		bat_priv->mcast.flags = mcast_data.flags;
  		bat_priv->mcast.enabled = true;
  	}

  	return !(mcast_data.flags & BATADV_MCAST_WANT_ALL_IPV4 &&
  		 mcast_data.flags & BATADV_MCAST_WANT_ALL_IPV6);

  }
  
  /**

   * __batadv_mcast_mla_update - update the own MLAs

   * @bat_priv: the bat priv with all the soft interface information
   *

   * Updates the own multicast listener announcements in the translation
   * table as well as the own, announced multicast tvlv container.

   *
   * Note that non-conflicting reads and writes to bat_priv->mcast.mla_list
   * in batadv_mcast_mla_tt_retract() and batadv_mcast_mla_tt_add() are
   * ensured by the non-parallel execution of the worker this function
   * belongs to.

   */

  static void __batadv_mcast_mla_update(struct batadv_priv *bat_priv)

  {
  	struct net_device *soft_iface = bat_priv->soft_iface;
  	struct hlist_head mcast_list = HLIST_HEAD_INIT;
  	int ret;

  	if (!batadv_mcast_mla_tvlv_update(bat_priv))

  		goto update;
  
  	ret = batadv_mcast_mla_softif_get(soft_iface, &mcast_list);
  	if (ret < 0)
  		goto out;

  	ret = batadv_mcast_mla_bridge_get(soft_iface, &mcast_list);
  	if (ret < 0)
  		goto out;

  update:
  	batadv_mcast_mla_tt_retract(bat_priv, &mcast_list);
  	batadv_mcast_mla_tt_add(bat_priv, &mcast_list);
  
  out:

  	batadv_mcast_mla_list_free(&mcast_list);

  }
  
  /**

   * batadv_mcast_mla_update - update the own MLAs
   * @work: kernel work struct
   *
   * Updates the own multicast listener announcements in the translation
   * table as well as the own, announced multicast tvlv container.
   *
   * In the end, reschedules the work timer.
   */
  static void batadv_mcast_mla_update(struct work_struct *work)
  {
  	struct delayed_work *delayed_work;
  	struct batadv_priv_mcast *priv_mcast;
  	struct batadv_priv *bat_priv;
  
  	delayed_work = to_delayed_work(work);
  	priv_mcast = container_of(delayed_work, struct batadv_priv_mcast, work);
  	bat_priv = container_of(priv_mcast, struct batadv_priv, mcast);
  
  	__batadv_mcast_mla_update(bat_priv);
  	batadv_mcast_start_timer(bat_priv);
  }
  
  /**

   * batadv_mcast_is_report_ipv4 - check for IGMP reports
   * @skb: the ethernet frame destined for the mesh
   *
   * This call might reallocate skb data.
   *
   * Checks whether the given frame is a valid IGMP report.
   *
   * Return: If so then true, otherwise false.
   */
  static bool batadv_mcast_is_report_ipv4(struct sk_buff *skb)
  {
  	if (ip_mc_check_igmp(skb, NULL) < 0)
  		return false;
  
  	switch (igmp_hdr(skb)->type) {
  	case IGMP_HOST_MEMBERSHIP_REPORT:
  	case IGMPV2_HOST_MEMBERSHIP_REPORT:
  	case IGMPV3_HOST_MEMBERSHIP_REPORT:
  		return true;
  	}
  
  	return false;
  }
  
  /**

   * batadv_mcast_forw_mode_check_ipv4 - check for optimized forwarding potential
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: the IPv4 packet to check
   * @is_unsnoopable: stores whether the destination is snoopable
   *
   * Checks whether the given IPv4 packet has the potential to be forwarded with a
   * mode more optimal than classic flooding.
   *

   * Return: If so then 0. Otherwise -EINVAL or -ENOMEM in case of memory
   * allocation failure.

   */
  static int batadv_mcast_forw_mode_check_ipv4(struct batadv_priv *bat_priv,
  					     struct sk_buff *skb,
  					     bool *is_unsnoopable)
  {
  	struct iphdr *iphdr;
  
  	/* We might fail due to out-of-memory -> drop it */
  	if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*iphdr)))
  		return -ENOMEM;

  	if (batadv_mcast_is_report_ipv4(skb))
  		return -EINVAL;

  	iphdr = ip_hdr(skb);
  
  	/* TODO: Implement Multicast Router Discovery (RFC4286),
  	 * then allow scope > link local, too
  	 */
  	if (!ipv4_is_local_multicast(iphdr->daddr))
  		return -EINVAL;
  
  	/* link-local multicast listeners behind a bridge are
  	 * not snoopable (see RFC4541, section 2.1.2.2)
  	 */
  	*is_unsnoopable = true;
  
  	return 0;
  }

  /**
   * batadv_mcast_is_report_ipv6 - check for MLD reports
   * @skb: the ethernet frame destined for the mesh
   *
   * This call might reallocate skb data.
   *
   * Checks whether the given frame is a valid MLD report.
   *
   * Return: If so then true, otherwise false.
   */
  static bool batadv_mcast_is_report_ipv6(struct sk_buff *skb)
  {
  	if (ipv6_mc_check_mld(skb, NULL) < 0)
  		return false;
  
  	switch (icmp6_hdr(skb)->icmp6_type) {
  	case ICMPV6_MGM_REPORT:
  	case ICMPV6_MLD2_REPORT:
  		return true;
  	}
  
  	return false;
  }

  /**

   * batadv_mcast_forw_mode_check_ipv6 - check for optimized forwarding potential
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: the IPv6 packet to check

   * @is_unsnoopable: stores whether the destination is snoopable

   *
   * Checks whether the given IPv6 packet has the potential to be forwarded with a
   * mode more optimal than classic flooding.
   *

   * Return: If so then 0. Otherwise -EINVAL is or -ENOMEM if we are out of memory

   */
  static int batadv_mcast_forw_mode_check_ipv6(struct batadv_priv *bat_priv,

  					     struct sk_buff *skb,
  					     bool *is_unsnoopable)

  {
  	struct ipv6hdr *ip6hdr;
  
  	/* We might fail due to out-of-memory -> drop it */
  	if (!pskb_may_pull(skb, sizeof(struct ethhdr) + sizeof(*ip6hdr)))
  		return -ENOMEM;

  	if (batadv_mcast_is_report_ipv6(skb))
  		return -EINVAL;

  	ip6hdr = ipv6_hdr(skb);
  
  	/* TODO: Implement Multicast Router Discovery (RFC4286),
  	 * then allow scope > link local, too
  	 */
  	if (IPV6_ADDR_MC_SCOPE(&ip6hdr->daddr) != IPV6_ADDR_SCOPE_LINKLOCAL)
  		return -EINVAL;
  
  	/* link-local-all-nodes multicast listeners behind a bridge are
  	 * not snoopable (see RFC4541, section 3, paragraph 3)
  	 */
  	if (ipv6_addr_is_ll_all_nodes(&ip6hdr->daddr))

  		*is_unsnoopable = true;

  
  	return 0;
  }
  
  /**
   * batadv_mcast_forw_mode_check - check for optimized forwarding potential
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: the multicast frame to check

   * @is_unsnoopable: stores whether the destination is snoopable

   *
   * Checks whether the given multicast ethernet frame has the potential to be
   * forwarded with a mode more optimal than classic flooding.
   *

   * Return: If so then 0. Otherwise -EINVAL is or -ENOMEM if we are out of memory

   */
  static int batadv_mcast_forw_mode_check(struct batadv_priv *bat_priv,

  					struct sk_buff *skb,
  					bool *is_unsnoopable)

  {
  	struct ethhdr *ethhdr = eth_hdr(skb);
  
  	if (!atomic_read(&bat_priv->multicast_mode))
  		return -EINVAL;
  
  	if (atomic_read(&bat_priv->mcast.num_disabled))
  		return -EINVAL;
  
  	switch (ntohs(ethhdr->h_proto)) {

  	case ETH_P_IP:
  		return batadv_mcast_forw_mode_check_ipv4(bat_priv, skb,
  							 is_unsnoopable);

  	case ETH_P_IPV6:

  		if (!IS_ENABLED(CONFIG_IPV6))
  			return -EINVAL;

  		return batadv_mcast_forw_mode_check_ipv6(bat_priv, skb,
  							 is_unsnoopable);

  	default:
  		return -EINVAL;
  	}
  }
  
  /**

   * batadv_mcast_forw_want_all_ip_count - count nodes with unspecific mcast
   *  interest

   * @bat_priv: the bat priv with all the soft interface information
   * @ethhdr: ethernet header of a packet
   *

   * Return: the number of nodes which want all IPv4 multicast traffic if the

   * given ethhdr is from an IPv4 packet or the number of nodes which want all
   * IPv6 traffic if it matches an IPv6 packet.
   */
  static int batadv_mcast_forw_want_all_ip_count(struct batadv_priv *bat_priv,
  					       struct ethhdr *ethhdr)
  {
  	switch (ntohs(ethhdr->h_proto)) {
  	case ETH_P_IP:
  		return atomic_read(&bat_priv->mcast.num_want_all_ipv4);
  	case ETH_P_IPV6:
  		return atomic_read(&bat_priv->mcast.num_want_all_ipv6);
  	default:
  		/* we shouldn't be here... */
  		return 0;
  	}
  }
  
  /**

   * batadv_mcast_forw_tt_node_get - get a multicast tt node
   * @bat_priv: the bat priv with all the soft interface information
   * @ethhdr: the ether header containing the multicast destination
   *

   * Return: an orig_node matching the multicast address provided by ethhdr

   * via a translation table lookup. This increases the returned nodes refcount.
   */
  static struct batadv_orig_node *
  batadv_mcast_forw_tt_node_get(struct batadv_priv *bat_priv,
  			      struct ethhdr *ethhdr)
  {

  	return batadv_transtable_search(bat_priv, NULL, ethhdr->h_dest,
  					BATADV_NO_FLAGS);

  }
  
  /**

   * batadv_mcast_forw_ipv4_node_get - get a node with an ipv4 flag

   * @bat_priv: the bat priv with all the soft interface information
   *

   * Return: an orig_node which has the BATADV_MCAST_WANT_ALL_IPV4 flag set and

   * increases its refcount.
   */
  static struct batadv_orig_node *
  batadv_mcast_forw_ipv4_node_get(struct batadv_priv *bat_priv)
  {
  	struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(tmp_orig_node,
  				 &bat_priv->mcast.want_all_ipv4_list,
  				 mcast_want_all_ipv4_node) {

  		if (!kref_get_unless_zero(&tmp_orig_node->refcount))

  			continue;
  
  		orig_node = tmp_orig_node;
  		break;
  	}
  	rcu_read_unlock();
  
  	return orig_node;
  }
  
  /**

   * batadv_mcast_forw_ipv6_node_get - get a node with an ipv6 flag

   * @bat_priv: the bat priv with all the soft interface information
   *

   * Return: an orig_node which has the BATADV_MCAST_WANT_ALL_IPV6 flag set

   * and increases its refcount.
   */
  static struct batadv_orig_node *
  batadv_mcast_forw_ipv6_node_get(struct batadv_priv *bat_priv)
  {
  	struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(tmp_orig_node,
  				 &bat_priv->mcast.want_all_ipv6_list,
  				 mcast_want_all_ipv6_node) {

  		if (!kref_get_unless_zero(&tmp_orig_node->refcount))

  			continue;
  
  		orig_node = tmp_orig_node;
  		break;
  	}
  	rcu_read_unlock();
  
  	return orig_node;
  }
  
  /**

   * batadv_mcast_forw_ip_node_get - get a node with an ipv4/ipv6 flag

   * @bat_priv: the bat priv with all the soft interface information
   * @ethhdr: an ethernet header to determine the protocol family from
   *

   * Return: an orig_node which has the BATADV_MCAST_WANT_ALL_IPV4 or

   * BATADV_MCAST_WANT_ALL_IPV6 flag, depending on the provided ethhdr, set and
   * increases its refcount.
   */
  static struct batadv_orig_node *
  batadv_mcast_forw_ip_node_get(struct batadv_priv *bat_priv,
  			      struct ethhdr *ethhdr)
  {
  	switch (ntohs(ethhdr->h_proto)) {
  	case ETH_P_IP:
  		return batadv_mcast_forw_ipv4_node_get(bat_priv);
  	case ETH_P_IPV6:
  		return batadv_mcast_forw_ipv6_node_get(bat_priv);
  	default:
  		/* we shouldn't be here... */
  		return NULL;
  	}
  }
  
  /**

   * batadv_mcast_forw_unsnoop_node_get - get a node with an unsnoopable flag

   * @bat_priv: the bat priv with all the soft interface information
   *

   * Return: an orig_node which has the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag

   * set and increases its refcount.
   */
  static struct batadv_orig_node *
  batadv_mcast_forw_unsnoop_node_get(struct batadv_priv *bat_priv)
  {
  	struct batadv_orig_node *tmp_orig_node, *orig_node = NULL;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(tmp_orig_node,
  				 &bat_priv->mcast.want_all_unsnoopables_list,
  				 mcast_want_all_unsnoopables_node) {

  		if (!kref_get_unless_zero(&tmp_orig_node->refcount))

  			continue;
  
  		orig_node = tmp_orig_node;
  		break;
  	}
  	rcu_read_unlock();
  
  	return orig_node;
  }
  
  /**

   * batadv_mcast_forw_mode - check on how to forward a multicast packet
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: The multicast packet to check
   * @orig: an originator to be set to forward the skb to
   *

   * Return: the forwarding mode as enum batadv_forw_mode and in case of

   * BATADV_FORW_SINGLE set the orig to the single originator the skb
   * should be forwarded to.
   */
  enum batadv_forw_mode
  batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
  		       struct batadv_orig_node **orig)
  {

  	int ret, tt_count, ip_count, unsnoop_count, total_count;

  	bool is_unsnoopable = false;

  	struct ethhdr *ethhdr;

  	ret = batadv_mcast_forw_mode_check(bat_priv, skb, &is_unsnoopable);

  	if (ret == -ENOMEM)
  		return BATADV_FORW_NONE;
  	else if (ret < 0)
  		return BATADV_FORW_ALL;
  
  	ethhdr = eth_hdr(skb);
  
  	tt_count = batadv_tt_global_hash_count(bat_priv, ethhdr->h_dest,
  					       BATADV_NO_FLAGS);

  	ip_count = batadv_mcast_forw_want_all_ip_count(bat_priv, ethhdr);

  	unsnoop_count = !is_unsnoopable ? 0 :
  			atomic_read(&bat_priv->mcast.num_want_all_unsnoopables);

  	total_count = tt_count + ip_count + unsnoop_count;

  	switch (total_count) {

  	case 1:

  		if (tt_count)
  			*orig = batadv_mcast_forw_tt_node_get(bat_priv, ethhdr);

  		else if (ip_count)
  			*orig = batadv_mcast_forw_ip_node_get(bat_priv, ethhdr);

  		else if (unsnoop_count)
  			*orig = batadv_mcast_forw_unsnoop_node_get(bat_priv);

  		if (*orig)
  			return BATADV_FORW_SINGLE;
  
  		/* fall through */
  	case 0:
  		return BATADV_FORW_NONE;
  	default:
  		return BATADV_FORW_ALL;
  	}
  }
  
  /**

   * batadv_mcast_want_unsnoop_update - update unsnoop counter and list
   * @bat_priv: the bat priv with all the soft interface information
   * @orig: the orig_node which multicast state might have changed of
   * @mcast_flags: flags indicating the new multicast state
   *
   * If the BATADV_MCAST_WANT_ALL_UNSNOOPABLES flag of this originator,
   * orig, has toggled then this method updates counter and list accordingly.

   *
   * Caller needs to hold orig->mcast_handler_lock.

   */
  static void batadv_mcast_want_unsnoop_update(struct batadv_priv *bat_priv,
  					     struct batadv_orig_node *orig,

  					     u8 mcast_flags)

  {

  	struct hlist_node *node = &orig->mcast_want_all_unsnoopables_node;
  	struct hlist_head *head = &bat_priv->mcast.want_all_unsnoopables_list;

  	lockdep_assert_held(&orig->mcast_handler_lock);

  	/* switched from flag unset to set */
  	if (mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
  	    !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES)) {
  		atomic_inc(&bat_priv->mcast.num_want_all_unsnoopables);
  
  		spin_lock_bh(&bat_priv->mcast.want_lists_lock);

  		/* flag checks above + mcast_handler_lock prevents this */
  		WARN_ON(!hlist_unhashed(node));
  
  		hlist_add_head_rcu(node, head);

  		spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
  	/* switched from flag set to unset */
  	} else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) &&
  		   orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) {
  		atomic_dec(&bat_priv->mcast.num_want_all_unsnoopables);
  
  		spin_lock_bh(&bat_priv->mcast.want_lists_lock);

  		/* flag checks above + mcast_handler_lock prevents this */
  		WARN_ON(hlist_unhashed(node));
  
  		hlist_del_init_rcu(node);

  		spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
  	}
  }
  
  /**

   * batadv_mcast_want_ipv4_update - update want-all-ipv4 counter and list
   * @bat_priv: the bat priv with all the soft interface information
   * @orig: the orig_node which multicast state might have changed of
   * @mcast_flags: flags indicating the new multicast state
   *
   * If the BATADV_MCAST_WANT_ALL_IPV4 flag of this originator, orig, has
   * toggled then this method updates counter and list accordingly.

   *
   * Caller needs to hold orig->mcast_handler_lock.

   */
  static void batadv_mcast_want_ipv4_update(struct batadv_priv *bat_priv,
  					  struct batadv_orig_node *orig,

  					  u8 mcast_flags)

  {

  	struct hlist_node *node = &orig->mcast_want_all_ipv4_node;
  	struct hlist_head *head = &bat_priv->mcast.want_all_ipv4_list;

  	lockdep_assert_held(&orig->mcast_handler_lock);

  	/* switched from flag unset to set */
  	if (mcast_flags & BATADV_MCAST_WANT_ALL_IPV4 &&
  	    !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV4)) {
  		atomic_inc(&bat_priv->mcast.num_want_all_ipv4);
  
  		spin_lock_bh(&bat_priv->mcast.want_lists_lock);

  		/* flag checks above + mcast_handler_lock prevents this */
  		WARN_ON(!hlist_unhashed(node));
  
  		hlist_add_head_rcu(node, head);

  		spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
  	/* switched from flag set to unset */
  	} else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_IPV4) &&
  		   orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV4) {
  		atomic_dec(&bat_priv->mcast.num_want_all_ipv4);
  
  		spin_lock_bh(&bat_priv->mcast.want_lists_lock);

  		/* flag checks above + mcast_handler_lock prevents this */
  		WARN_ON(hlist_unhashed(node));
  
  		hlist_del_init_rcu(node);

  		spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
  	}
  }
  
  /**
   * batadv_mcast_want_ipv6_update - update want-all-ipv6 counter and list
   * @bat_priv: the bat priv with all the soft interface information
   * @orig: the orig_node which multicast state might have changed of
   * @mcast_flags: flags indicating the new multicast state
   *
   * If the BATADV_MCAST_WANT_ALL_IPV6 flag of this originator, orig, has
   * toggled then this method updates counter and list accordingly.

   *
   * Caller needs to hold orig->mcast_handler_lock.

   */
  static void batadv_mcast_want_ipv6_update(struct batadv_priv *bat_priv,
  					  struct batadv_orig_node *orig,

  					  u8 mcast_flags)

  {

  	struct hlist_node *node = &orig->mcast_want_all_ipv6_node;
  	struct hlist_head *head = &bat_priv->mcast.want_all_ipv6_list;

  	lockdep_assert_held(&orig->mcast_handler_lock);

  	/* switched from flag unset to set */
  	if (mcast_flags & BATADV_MCAST_WANT_ALL_IPV6 &&
  	    !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV6)) {
  		atomic_inc(&bat_priv->mcast.num_want_all_ipv6);
  
  		spin_lock_bh(&bat_priv->mcast.want_lists_lock);

  		/* flag checks above + mcast_handler_lock prevents this */
  		WARN_ON(!hlist_unhashed(node));
  
  		hlist_add_head_rcu(node, head);

  		spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
  	/* switched from flag set to unset */
  	} else if (!(mcast_flags & BATADV_MCAST_WANT_ALL_IPV6) &&
  		   orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV6) {
  		atomic_dec(&bat_priv->mcast.num_want_all_ipv6);
  
  		spin_lock_bh(&bat_priv->mcast.want_lists_lock);

  		/* flag checks above + mcast_handler_lock prevents this */
  		WARN_ON(hlist_unhashed(node));
  
  		hlist_del_init_rcu(node);

  		spin_unlock_bh(&bat_priv->mcast.want_lists_lock);
  	}
  }
  
  /**

   * batadv_mcast_tvlv_ogm_handler - 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(struct batadv_priv *bat_priv,
  					  struct batadv_orig_node *orig,
  					  u8 flags,
  					  void *tvlv_value,
  					  u16 tvlv_value_len)

  {
  	bool orig_mcast_enabled = !(flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND);

  	u8 mcast_flags = BATADV_NO_FLAGS;

  	bool orig_initialized;

  	if (orig_mcast_enabled && tvlv_value &&
  	    (tvlv_value_len >= sizeof(mcast_flags)))

  		mcast_flags = *(u8 *)tvlv_value;

  
  	spin_lock_bh(&orig->mcast_handler_lock);

  	orig_initialized = test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
  				    &orig->capa_initialized);

  
  	/* 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 &&

  	    !test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities)) {

  		if (orig_initialized)
  			atomic_dec(&bat_priv->mcast.num_disabled);

  		set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);

  	/* If mcast support is being switched off or if this is an initial
  	 * OGM without mcast support then increase the disabled mcast
  	 * node counter.

  	 */
  	} else if (!orig_mcast_enabled &&

  		   (test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) ||

  		    !orig_initialized)) {

  		atomic_inc(&bat_priv->mcast.num_disabled);

  		clear_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities);

  	}

  	set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized);

  	batadv_mcast_want_unsnoop_update(bat_priv, orig, mcast_flags);

  	batadv_mcast_want_ipv4_update(bat_priv, orig, mcast_flags);
  	batadv_mcast_want_ipv6_update(bat_priv, orig, mcast_flags);

  	orig->mcast_flags = mcast_flags;

  	spin_unlock_bh(&orig->mcast_handler_lock);

  }
  
  /**
   * 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,
  				     NULL, BATADV_TVLV_MCAST, 2,

  				     BATADV_TVLV_HANDLER_OGM_CIFNOTFND);

  
  	INIT_DELAYED_WORK(&bat_priv->mcast.work, batadv_mcast_mla_update);
  	batadv_mcast_start_timer(bat_priv);

  }

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  /**

   * batadv_mcast_flags_print_header - print own mcast flags to debugfs table
   * @bat_priv: the bat priv with all the soft interface information
   * @seq: debugfs table seq_file struct
   *
   * Prints our own multicast flags including a more specific reason why
   * they are set, that is prints the bridge and querier state too, to
   * the debugfs table specified via @seq.
   */
  static void batadv_mcast_flags_print_header(struct batadv_priv *bat_priv,
  					    struct seq_file *seq)
  {
  	u8 flags = bat_priv->mcast.flags;
  	char querier4, querier6, shadowing4, shadowing6;
  	bool bridged = bat_priv->mcast.bridged;
  
  	if (bridged) {
  		querier4 = bat_priv->mcast.querier_ipv4.exists ? '.' : '4';
  		querier6 = bat_priv->mcast.querier_ipv6.exists ? '.' : '6';
  		shadowing4 = bat_priv->mcast.querier_ipv4.shadowing ? '4' : '.';
  		shadowing6 = bat_priv->mcast.querier_ipv6.shadowing ? '6' : '.';
  	} else {
  		querier4 = '?';
  		querier6 = '?';
  		shadowing4 = '?';
  		shadowing6 = '?';
  	}
  
  	seq_printf(seq, "Multicast flags (own flags: [%c%c%c])
  ",
  		   (flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES) ? 'U' : '.',
  		   (flags & BATADV_MCAST_WANT_ALL_IPV4) ? '4' : '.',
  		   (flags & BATADV_MCAST_WANT_ALL_IPV6) ? '6' : '.');
  	seq_printf(seq, "* Bridged [U]\t\t\t\t%c
  ", bridged ? 'U' : '.');
  	seq_printf(seq, "* No IGMP/MLD Querier [4/6]:\t\t%c/%c
  ",
  		   querier4, querier6);
  	seq_printf(seq, "* Shadowing IGMP/MLD Querier [4/6]:\t%c/%c
  ",
  		   shadowing4, shadowing6);
  	seq_puts(seq, "-------------------------------------------
  ");
  	seq_printf(seq, "       %-10s %s
  ", "Originator", "Flags");
  }
  
  /**
   * batadv_mcast_flags_seq_print_text - print the mcast flags of other nodes
   * @seq: seq file to print on
   * @offset: not used
   *
   * This prints a table of (primary) originators and their according
   * multicast flags, including (in the header) our own.
   *
   * Return: always 0
   */
  int batadv_mcast_flags_seq_print_text(struct seq_file *seq, void *offset)
  {
  	struct net_device *net_dev = (struct net_device *)seq->private;
  	struct batadv_priv *bat_priv = netdev_priv(net_dev);
  	struct batadv_hard_iface *primary_if;
  	struct batadv_hashtable *hash = bat_priv->orig_hash;
  	struct batadv_orig_node *orig_node;
  	struct hlist_head *head;
  	u8 flags;
  	u32 i;
  
  	primary_if = batadv_seq_print_text_primary_if_get(seq);
  	if (!primary_if)
  		return 0;
  
  	batadv_mcast_flags_print_header(bat_priv, seq);
  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];
  
  		rcu_read_lock();
  		hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
  			if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
  				      &orig_node->capa_initialized))
  				continue;
  
  			if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST,
  				      &orig_node->capabilities)) {
  				seq_printf(seq, "%pM -
  ", orig_node->orig);
  				continue;
  			}
  
  			flags = orig_node->mcast_flags;
  
  			seq_printf(seq, "%pM [%c%c%c]
  ", orig_node->orig,
  				   (flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES)
  				   ? 'U' : '.',
  				   (flags & BATADV_MCAST_WANT_ALL_IPV4)
  				   ? '4' : '.',
  				   (flags & BATADV_MCAST_WANT_ALL_IPV6)
  				   ? '6' : '.');
  		}
  		rcu_read_unlock();
  	}
  
  	batadv_hardif_put(primary_if);
  
  	return 0;
  }

  #endif

  
  /**

   * 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)
  {

  	cancel_delayed_work_sync(&bat_priv->mcast.work);

  	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_MCAST, 2);
  	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_MCAST, 2);

  	/* safely calling outside of worker, as worker was canceled above */

  	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;

  	spin_lock_bh(&orig->mcast_handler_lock);

  	if (!test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities) &&
  	    test_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized))

  		atomic_dec(&bat_priv->mcast.num_disabled);

  
  	batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS);

  	batadv_mcast_want_ipv4_update(bat_priv, orig, BATADV_NO_FLAGS);
  	batadv_mcast_want_ipv6_update(bat_priv, orig, BATADV_NO_FLAGS);

  
  	spin_unlock_bh(&orig->mcast_handler_lock);

  }