// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich, Antonio Quartulli
 */

#include "translation-table.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/build_bug.h>
#include <linux/byteorder/generic.h>
#include <linux/cache.h>
#include <linux/compiler.h>
#include <linux/container_of.h>
#include <linux/crc32.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/overflow.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <net/genetlink.h>
#include <net/netlink.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>

#include "bridge_loop_avoidance.h"
#include "hard-interface.h"
#include "hash.h"
#include "log.h"
#include "mesh-interface.h"
#include "netlink.h"
#include "originator.h"
#include "tvlv.h"

static struct kmem_cache *batadv_tl_cache __read_mostly;
static struct kmem_cache *batadv_tg_cache __read_mostly;
static struct kmem_cache *batadv_tt_orig_cache __read_mostly;
static struct kmem_cache *batadv_tt_change_cache __read_mostly;
static struct kmem_cache *batadv_tt_req_cache __read_mostly;
static struct kmem_cache *batadv_tt_roam_cache __read_mostly;

/* hash class keys */
static struct lock_class_key batadv_tt_local_hash_lock_class_key;
static struct lock_class_key batadv_tt_global_hash_lock_class_key;

static void batadv_send_roam_adv(struct batadv_priv *bat_priv, u8 *client,
				 unsigned short vid,
				 struct batadv_orig_node *orig_node);
static void batadv_tt_purge(struct work_struct *work);
static void
batadv_tt_global_del_orig_list(struct batadv_tt_global_entry *tt_global_entry);
static void batadv_tt_global_del(struct batadv_priv *bat_priv,
				 struct batadv_orig_node *orig_node,
				 const unsigned char *addr,
				 unsigned short vid, const char *message,
				 bool roaming);

/**
 * batadv_compare_tt() - check if two TT entries are the same
 * @node: the list element pointer of the first TT entry
 * @data2: pointer to the tt_common_entry of the second TT entry
 *
 * Compare the MAC address and the VLAN ID of the two TT entries and check if
 * they are the same TT client.
 * Return: true if the two TT clients are the same, false otherwise
 */
static bool batadv_compare_tt(const struct hlist_node *node, const void *data2)
{
	const void *data1 = container_of(node, struct batadv_tt_common_entry,
					 hash_entry);
	const struct batadv_tt_common_entry *tt1 = data1;
	const struct batadv_tt_common_entry *tt2 = data2;

	return (tt1->vid == tt2->vid) && batadv_compare_eth(data1, data2);
}

/**
 * batadv_choose_tt() - return the index of the tt entry in the hash table
 * @data: pointer to the tt_common_entry object to map
 * @size: the size of the hash table
 *
 * Return: the hash index where the object represented by 'data' should be
 * stored at.
 */
static inline u32 batadv_choose_tt(const void *data, u32 size)
{
	const struct batadv_tt_common_entry *tt;
	u32 hash = 0;

	tt = data;
	hash = jhash(&tt->addr, ETH_ALEN, hash);
	hash = jhash(&tt->vid, sizeof(tt->vid), hash);

	return hash % size;
}

/**
 * batadv_tt_hash_find() - look for a client in the given hash table
 * @hash: the hash table to search
 * @addr: the mac address of the client to look for
 * @vid: VLAN identifier
 *
 * Return: a pointer to the tt_common struct belonging to the searched client if
 * found, NULL otherwise.
 */
static struct batadv_tt_common_entry *
batadv_tt_hash_find(struct batadv_hashtable *hash, const u8 *addr,
		    unsigned short vid)
{
	struct batadv_tt_common_entry *tt_tmp = NULL;
	struct batadv_tt_common_entry to_search;
	struct batadv_tt_common_entry *tt;
	struct hlist_head *head;
	u32 index;

	if (!hash)
		return NULL;

	ether_addr_copy(to_search.addr, addr);
	to_search.vid = vid;

	index = batadv_choose_tt(&to_search, hash->size);
	head = &hash->table[index];

	rcu_read_lock();
	hlist_for_each_entry_rcu(tt, head, hash_entry) {
		if (!batadv_compare_eth(tt, addr))
			continue;

		if (tt->vid != vid)
			continue;

		if (!kref_get_unless_zero(&tt->refcount))
			continue;

		tt_tmp = tt;
		break;
	}
	rcu_read_unlock();

	return tt_tmp;
}

/**
 * batadv_tt_local_hash_find() - search the local table for a given client
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the client to look for
 * @vid: VLAN identifier
 *
 * Return: a pointer to the corresponding tt_local_entry struct if the client is
 * found, NULL otherwise.
 */
static struct batadv_tt_local_entry *
batadv_tt_local_hash_find(struct batadv_priv *bat_priv, const u8 *addr,
			  unsigned short vid)
{
	struct batadv_tt_local_entry *tt_local_entry = NULL;
	struct batadv_tt_common_entry *tt_common_entry;

	tt_common_entry = batadv_tt_hash_find(bat_priv->tt.local_hash, addr,
					      vid);
	if (tt_common_entry)
		tt_local_entry = container_of(tt_common_entry,
					      struct batadv_tt_local_entry,
					      common);
	return tt_local_entry;
}

/**
 * batadv_tt_global_hash_find() - search the global table for a given client
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the client to look for
 * @vid: VLAN identifier
 *
 * Return: a pointer to the corresponding tt_global_entry struct if the client
 * is found, NULL otherwise.
 */
struct batadv_tt_global_entry *
batadv_tt_global_hash_find(struct batadv_priv *bat_priv, const u8 *addr,
			   unsigned short vid)
{
	struct batadv_tt_global_entry *tt_global_entry = NULL;
	struct batadv_tt_common_entry *tt_common_entry;

	tt_common_entry = batadv_tt_hash_find(bat_priv->tt.global_hash, addr,
					      vid);
	if (tt_common_entry)
		tt_global_entry = container_of(tt_common_entry,
					       struct batadv_tt_global_entry,
					       common);
	return tt_global_entry;
}

/**
 * batadv_tt_local_entry_release() - release tt_local_entry from lists and queue
 *  for free after rcu grace period
 * @ref: kref pointer of the batadv_tt_local_entry
 */
static void batadv_tt_local_entry_release(struct kref *ref)
{
	struct batadv_tt_local_entry *tt_local_entry;

	tt_local_entry = container_of(ref, struct batadv_tt_local_entry,
				      common.refcount);

	batadv_meshif_vlan_put(tt_local_entry->vlan);

	kfree_rcu(tt_local_entry, common.rcu);
}

/**
 * batadv_tt_local_entry_put() - decrement the tt_local_entry refcounter and
 *  possibly release it
 * @tt_local_entry: tt_local_entry to be free'd
 */
static void
batadv_tt_local_entry_put(struct batadv_tt_local_entry *tt_local_entry)
{
	if (!tt_local_entry)
		return;

	kref_put(&tt_local_entry->common.refcount,
		 batadv_tt_local_entry_release);
}

/**
 * batadv_tt_global_entry_release() - release tt_global_entry from lists and
 *  queue for free after rcu grace period
 * @ref: kref pointer of the batadv_tt_global_entry
 */
void batadv_tt_global_entry_release(struct kref *ref)
{
	struct batadv_tt_global_entry *tt_global_entry;

	tt_global_entry = container_of(ref, struct batadv_tt_global_entry,
				       common.refcount);

	batadv_tt_global_del_orig_list(tt_global_entry);

	kfree_rcu(tt_global_entry, common.rcu);
}

/**
 * batadv_tt_global_hash_count() - count the number of orig entries
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the client to count entries for
 * @vid: VLAN identifier
 *
 * Return: the number of originators advertising the given address/data
 * (excluding our self).
 */
int batadv_tt_global_hash_count(struct batadv_priv *bat_priv,
				const u8 *addr, unsigned short vid)
{
	struct batadv_tt_global_entry *tt_global_entry;
	int count;

	tt_global_entry = batadv_tt_global_hash_find(bat_priv, addr, vid);
	if (!tt_global_entry)
		return 0;

	count = atomic_read(&tt_global_entry->orig_list_count);
	batadv_tt_global_entry_put(tt_global_entry);

	return count;
}

/**
 * batadv_tt_local_size_mod() - change the size by v of the local table
 *  identified by vid
 * @bat_priv: the bat priv with all the mesh interface information
 * @vid: the VLAN identifier of the sub-table to change
 * @v: the amount to sum to the local table size
 */
static void batadv_tt_local_size_mod(struct batadv_priv *bat_priv,
				     unsigned short vid, int v)
{
	struct batadv_meshif_vlan *vlan;

	vlan = batadv_meshif_vlan_get(bat_priv, vid);
	if (!vlan)
		return;

	atomic_add(v, &vlan->tt.num_entries);

	batadv_meshif_vlan_put(vlan);
}

/**
 * batadv_tt_local_size_inc() - increase by one the local table size for the
 *  given vid
 * @bat_priv: the bat priv with all the mesh interface information
 * @vid: the VLAN identifier
 */
static void batadv_tt_local_size_inc(struct batadv_priv *bat_priv,
				     unsigned short vid)
{
	batadv_tt_local_size_mod(bat_priv, vid, 1);
}

/**
 * batadv_tt_local_size_dec() - decrease by one the local table size for the
 *  given vid
 * @bat_priv: the bat priv with all the mesh interface information
 * @vid: the VLAN identifier
 */
static void batadv_tt_local_size_dec(struct batadv_priv *bat_priv,
				     unsigned short vid)
{
	batadv_tt_local_size_mod(bat_priv, vid, -1);
}

/**
 * batadv_tt_global_size_mod() - change the size by v of the global table
 *  for orig_node identified by vid
 * @orig_node: the originator for which the table has to be modified
 * @vid: the VLAN identifier
 * @v: the amount to sum to the global table size
 */
static void batadv_tt_global_size_mod(struct batadv_orig_node *orig_node,
				      unsigned short vid, int v)
{
	struct batadv_orig_node_vlan *vlan;

	vlan = batadv_orig_node_vlan_new(orig_node, vid);
	if (!vlan)
		return;

	if (atomic_add_return(v, &vlan->tt.num_entries) == 0) {
		spin_lock_bh(&orig_node->vlan_list_lock);
		if (!hlist_unhashed(&vlan->list)) {
			hlist_del_init_rcu(&vlan->list);
			batadv_orig_node_vlan_put(vlan);
		}
		spin_unlock_bh(&orig_node->vlan_list_lock);
	}

	batadv_orig_node_vlan_put(vlan);
}

/**
 * batadv_tt_global_size_inc() - increase by one the global table size for the
 *  given vid
 * @orig_node: the originator which global table size has to be decreased
 * @vid: the vlan identifier
 */
static void batadv_tt_global_size_inc(struct batadv_orig_node *orig_node,
				      unsigned short vid)
{
	batadv_tt_global_size_mod(orig_node, vid, 1);
}

/**
 * batadv_tt_global_size_dec() - decrease by one the global table size for the
 *  given vid
 * @orig_node: the originator which global table size has to be decreased
 * @vid: the vlan identifier
 */
static void batadv_tt_global_size_dec(struct batadv_orig_node *orig_node,
				      unsigned short vid)
{
	batadv_tt_global_size_mod(orig_node, vid, -1);
}

/**
 * batadv_tt_orig_list_entry_release() - release tt orig entry from lists and
 *  queue for free after rcu grace period
 * @ref: kref pointer of the tt orig entry
 */
static void batadv_tt_orig_list_entry_release(struct kref *ref)
{
	struct batadv_tt_orig_list_entry *orig_entry;

	orig_entry = container_of(ref, struct batadv_tt_orig_list_entry,
				  refcount);

	batadv_orig_node_put(orig_entry->orig_node);
	kfree_rcu(orig_entry, rcu);
}

/**
 * batadv_tt_orig_list_entry_put() - decrement the tt orig entry refcounter and
 *  possibly release it
 * @orig_entry: tt orig entry to be free'd
 */
static void
batadv_tt_orig_list_entry_put(struct batadv_tt_orig_list_entry *orig_entry)
{
	if (!orig_entry)
		return;

	kref_put(&orig_entry->refcount, batadv_tt_orig_list_entry_release);
}

/**
 * batadv_tt_local_event() - store a local TT event (ADD/DEL)
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_local_entry: the TT entry involved in the event
 * @event_flags: flags to store in the event structure
 */
static void batadv_tt_local_event(struct batadv_priv *bat_priv,
				  struct batadv_tt_local_entry *tt_local_entry,
				  u8 event_flags)
{
	struct batadv_tt_common_entry *common = &tt_local_entry->common;
	struct batadv_tt_change_node *tt_change_node;
	u8 flags = common->flags | event_flags;
	struct batadv_tt_change_node *entry;
	struct batadv_tt_change_node *safe;
	bool del_op_requested;
	bool del_op_entry;
	size_t changes;

	tt_change_node = kmem_cache_alloc(batadv_tt_change_cache, GFP_ATOMIC);
	if (!tt_change_node)
		return;

	tt_change_node->change.flags = flags;
	memset(tt_change_node->change.reserved, 0,
	       sizeof(tt_change_node->change.reserved));
	ether_addr_copy(tt_change_node->change.addr, common->addr);
	tt_change_node->change.vid = htons(common->vid);

	del_op_requested = flags & BATADV_TT_CLIENT_DEL;

	/* check for ADD+DEL, DEL+ADD, ADD+ADD or DEL+DEL events */
	spin_lock_bh(&bat_priv->tt.changes_list_lock);
	changes = READ_ONCE(bat_priv->tt.local_changes);
	list_for_each_entry_safe(entry, safe, &bat_priv->tt.changes_list,
				 list) {
		if (!batadv_compare_eth(entry->change.addr, common->addr))
			continue;

		if (entry->change.vid != tt_change_node->change.vid)
			continue;

		del_op_entry = entry->change.flags & BATADV_TT_CLIENT_DEL;
		if (del_op_requested != del_op_entry) {
			/* DEL+ADD in the same orig interval have no effect and
			 * can be removed to avoid silly behaviour on the
			 * receiver side. The  other way around (ADD+DEL) can
			 * happen in case of roaming of  a client still in the
			 * NEW state. Roaming of NEW clients is now possible due
			 * to automatically recognition of "temporary" clients
			 */
			list_del(&entry->list);
			kmem_cache_free(batadv_tt_change_cache, entry);
			changes--;
		} else {
			/* this is a second add or del in the same originator
			 * interval. It could mean that flags have been changed
			 * (e.g. double add): update them
			 */
			entry->change.flags = flags;
		}

		kmem_cache_free(batadv_tt_change_cache, tt_change_node);
		goto update_changes;
	}

	/* track the change in the OGMinterval list */
	list_add_tail(&tt_change_node->list, &bat_priv->tt.changes_list);
	changes++;

update_changes:
	WRITE_ONCE(bat_priv->tt.local_changes, changes);
	spin_unlock_bh(&bat_priv->tt.changes_list_lock);
}

/**
 * batadv_tt_len() - compute length in bytes of given number of tt changes
 * @changes_num: number of tt changes
 *
 * Return: computed length in bytes.
 */
static int batadv_tt_len(int changes_num)
{
	return changes_num * sizeof(struct batadv_tvlv_tt_change);
}

/**
 * batadv_tt_entries() - compute the number of entries fitting in tt_len bytes
 * @tt_len: available space
 *
 * Return: the number of entries.
 */
static u16 batadv_tt_entries(u16 tt_len)
{
	return tt_len / batadv_tt_len(1);
}

/**
 * batadv_tt_local_table_transmit_size() - calculates the local translation
 *  table size when transmitted over the air
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Return: local translation table size in bytes.
 */
static int batadv_tt_local_table_transmit_size(struct batadv_priv *bat_priv)
{
	struct batadv_meshif_vlan *vlan;
	u16 tt_local_entries = 0;
	u16 num_vlan = 0;
	int hdr_size;

	rcu_read_lock();
	hlist_for_each_entry_rcu(vlan, &bat_priv->meshif_vlan_list, list) {
		num_vlan++;
		tt_local_entries += atomic_read(&vlan->tt.num_entries);
	}
	rcu_read_unlock();

	/* header size of tvlv encapsulated tt response payload */
	hdr_size = sizeof(struct batadv_unicast_tvlv_packet);
	hdr_size += sizeof(struct batadv_tvlv_hdr);
	hdr_size += sizeof(struct batadv_tvlv_tt_data);
	hdr_size += num_vlan * sizeof(struct batadv_tvlv_tt_vlan_data);

	return hdr_size + batadv_tt_len(tt_local_entries);
}

/**
 * batadv_tt_local_init() - allocate and initialise the local translation table
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Return: 0 on success or -ENOMEM in case of allocation failure
 */
static int batadv_tt_local_init(struct batadv_priv *bat_priv)
{
	if (bat_priv->tt.local_hash)
		return 0;

	bat_priv->tt.local_hash = batadv_hash_new(1024);

	if (!bat_priv->tt.local_hash)
		return -ENOMEM;

	batadv_hash_set_lock_class(bat_priv->tt.local_hash,
				   &batadv_tt_local_hash_lock_class_key);

	return 0;
}

/**
 * batadv_tt_global_free() - drop a global translation table entry
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_global: the global TT entry to remove
 * @message: debug message explaining why the entry is being removed
 *
 * Remove @tt_global from the global TT hash and drop the reference held by
 * the hash.
 */
static void batadv_tt_global_free(struct batadv_priv *bat_priv,
				  struct batadv_tt_global_entry *tt_global,
				  const char *message)
{
	struct batadv_tt_global_entry *tt_removed_entry;
	struct hlist_node *tt_removed_node;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Deleting global tt entry %pM (vid: %d): %s\n",
		   tt_global->common.addr,
		   batadv_print_vid(tt_global->common.vid), message);

	tt_removed_node = batadv_hash_remove(bat_priv->tt.global_hash,
					     batadv_compare_tt,
					     batadv_choose_tt,
					     &tt_global->common);
	if (!tt_removed_node)
		return;

	/* drop reference of remove hash entry */
	tt_removed_entry = hlist_entry(tt_removed_node,
				       struct batadv_tt_global_entry,
				       common.hash_entry);
	batadv_tt_global_entry_put(tt_removed_entry);
}

/**
 * batadv_tt_local_add() - add a new client to the local table or update an
 *  existing client
 * @mesh_iface: netdev struct of the mesh interface
 * @addr: the mac address of the client to add
 * @vid: VLAN identifier
 * @ifindex: index of the interface where the client is connected to (useful to
 *  identify wireless clients)
 * @mark: the value contained in the skb->mark field of the received packet (if
 *  any)
 *
 * Return: true if the client was successfully added, false otherwise.
 */
bool batadv_tt_local_add(struct net_device *mesh_iface, const u8 *addr,
			 unsigned short vid, int ifindex, u32 mark)
{
	struct batadv_priv *bat_priv = netdev_priv(mesh_iface);
	struct batadv_tt_global_entry *tt_global = NULL;
	struct batadv_tt_orig_list_entry *orig_entry;
	struct batadv_tt_local_entry *tt_local;
	struct net *net = dev_net(mesh_iface);
	struct net_device *in_dev = NULL;
	struct batadv_meshif_vlan *vlan;
	bool roamed_back = false;
	bool iif_is_wifi = false;
	struct hlist_head *head;
	int packet_size_max;
	bool ret = false;
	u8 remote_flags;
	int hash_added;
	int table_size;
	u32 match_mark;

	if (ifindex != BATADV_NULL_IFINDEX)
		in_dev = dev_get_by_index(net, ifindex);

	if (in_dev) {
		u32 wifi_flags = batadv_netdev_get_wifi_flags(in_dev);

		iif_is_wifi = batadv_is_wifi(wifi_flags);
	}

	tt_local = batadv_tt_local_hash_find(bat_priv, addr, vid);

	if (!is_multicast_ether_addr(addr))
		tt_global = batadv_tt_global_hash_find(bat_priv, addr, vid);

	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 (vid: %d)\n",
				   addr, batadv_print_vid(vid));
			/* 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 (vid: %d) came back to its original location\n",
				   addr, batadv_print_vid(vid));
			/* 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;
	}

	/* Ignore the client if we cannot send it in a full table response. */
	table_size = batadv_tt_local_table_transmit_size(bat_priv);
	table_size += batadv_tt_len(1);
	packet_size_max = READ_ONCE(bat_priv->packet_size_max);
	if (table_size > packet_size_max) {
		net_ratelimited_function(batadv_info, mesh_iface,
					 "Local translation table size (%i) exceeds maximum packet size (%i); Ignoring new local tt entry: %pM\n",
					 table_size, packet_size_max, addr);
		goto out;
	}

	tt_local = kmem_cache_alloc(batadv_tl_cache, GFP_ATOMIC);
	if (!tt_local)
		goto out;

	/* increase the refcounter of the related vlan */
	vlan = batadv_meshif_vlan_get(bat_priv, vid);
	if (!vlan) {
		net_ratelimited_function(batadv_info, mesh_iface,
					 "adding TT local entry %pM to non-existent VLAN %d\n",
					 addr, batadv_print_vid(vid));
		kmem_cache_free(batadv_tl_cache, tt_local);
		tt_local = NULL;
		goto out;
	}

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Creating new local tt entry: %pM (vid: %d, ttvn: %d)\n",
		   addr, batadv_print_vid(vid),
		   (u8)atomic_read(&bat_priv->tt.vn));

	ether_addr_copy(tt_local->common.addr, addr);
	/* 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->common.flags = BATADV_TT_CLIENT_NEW;
	tt_local->common.vid = vid;
	if (iif_is_wifi)
		tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
	kref_init(&tt_local->common.refcount);
	tt_local->last_seen = jiffies;
	tt_local->common.added_at = tt_local->last_seen;
	tt_local->vlan = vlan;

	/* the batman interface mac and multicast addresses should never be
	 * purged
	 */
	if (batadv_compare_eth(addr, mesh_iface->dev_addr) ||
	    is_multicast_ether_addr(addr))
		tt_local->common.flags |= BATADV_TT_CLIENT_NOPURGE;

	kref_get(&tt_local->common.refcount);
	hash_added = batadv_hash_add(bat_priv->tt.local_hash, batadv_compare_tt,
				     batadv_choose_tt, &tt_local->common,
				     &tt_local->common.hash_entry);

	if (unlikely(hash_added != 0)) {
		/* remove the reference for the hash */
		batadv_tt_local_entry_put(tt_local);
		goto out;
	}

add_event:
	batadv_tt_local_event(bat_priv, tt_local, BATADV_NO_FLAGS);

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->orig_list;
		rcu_read_lock();
		hlist_for_each_entry_rcu(orig_entry, head, list) {
			batadv_send_roam_adv(bat_priv, tt_global->common.addr,
					     tt_global->common.vid,
					     orig_entry->orig_node);
		}
		rcu_read_unlock();
		if (roamed_back) {
			batadv_tt_global_free(bat_priv, tt_global,
					      "Roaming canceled");
		} 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;
		}
	}

	/* store the current remote flags before altering them. This helps
	 * understanding is flags are changing or not
	 */
	remote_flags = tt_local->common.flags & BATADV_TT_REMOTE_MASK;

	if (iif_is_wifi)
		tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
	else
		tt_local->common.flags &= ~BATADV_TT_CLIENT_WIFI;

	/* check the mark in the skb: if it's equal to the configured
	 * isolation_mark, it means the packet is coming from an isolated
	 * non-mesh client
	 */
	match_mark = (mark & bat_priv->isolation_mark_mask);
	if (bat_priv->isolation_mark_mask &&
	    match_mark == bat_priv->isolation_mark)
		tt_local->common.flags |= BATADV_TT_CLIENT_ISOLA;
	else
		tt_local->common.flags &= ~BATADV_TT_CLIENT_ISOLA;

	/* if any "dynamic" flag has been modified, resend an ADD event for this
	 * entry so that all the nodes can get the new flags
	 */
	if (remote_flags ^ (tt_local->common.flags & BATADV_TT_REMOTE_MASK))
		batadv_tt_local_event(bat_priv, tt_local, BATADV_NO_FLAGS);

	ret = true;
out:
	dev_put(in_dev);
	batadv_tt_local_entry_put(tt_local);
	batadv_tt_global_entry_put(tt_global);
	return ret;
}

/**
 * batadv_tt_prepare_tvlv_global_data() - prepare the TVLV TT header to send
 *  within a TT Response directed to another node
 * @orig_node: originator for which the TT data has to be prepared
 * @tt_data: uninitialised pointer to the address of the TVLV buffer
 * @tt_change: uninitialised pointer to the address of the area where the TT
 *  changed can be stored
 * @tt_len: pointer to the length to reserve to the tt_change. if -1 this
 *  function reserves the amount of space needed to send the entire global TT
 *  table. In case of success the value is updated with the real amount of
 *  reserved bytes
 * Allocate the needed amount of memory for the entire TT TVLV and write its
 * header made up of one tvlv_tt_data object and a series of tvlv_tt_vlan_data
 * objects, one per active VLAN served by the originator node.
 *
 * Return: the size of the allocated buffer or 0 in case of failure.
 */
static u16
batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node *orig_node,
				   struct batadv_tvlv_tt_data **tt_data,
				   struct batadv_tvlv_tt_change **tt_change,
				   s32 *tt_len)
{
	struct batadv_tvlv_tt_vlan_data *tt_vlan;
	struct batadv_orig_node_vlan *vlan;
	u16 total_entries = 0;
	size_t change_offset;
	u8 *tt_change_ptr;
	u16 num_vlan = 0;
	int vlan_entries;
	u16 sum_entries;
	u16 tvlv_len;

	spin_lock_bh(&orig_node->vlan_list_lock);
	hlist_for_each_entry(vlan, &orig_node->vlan_list, list) {
		vlan_entries = atomic_read(&vlan->tt.num_entries);

		if (check_add_overflow(vlan_entries, total_entries, &sum_entries)) {
			tvlv_len = 0;
			*tt_len = 0;
			goto out;
		}

		total_entries = sum_entries;
		num_vlan++;
	}

	change_offset = struct_size(*tt_data, vlan_data, num_vlan);

	/* if tt_len is negative, allocate the space needed by the full table */
	if (*tt_len < 0)
		*tt_len = batadv_tt_len(total_entries);

	if (check_add_overflow(*tt_len, change_offset, &tvlv_len)) {
		tvlv_len = 0;
		*tt_len = 0;
		goto out;
	}

	*tt_data = kmalloc(tvlv_len, GFP_ATOMIC);
	if (!*tt_data) {
		tvlv_len = 0;
		*tt_len = 0;
		goto out;
	}

	(*tt_data)->flags = BATADV_NO_FLAGS;
	(*tt_data)->ttvn = READ_ONCE(orig_node->last_ttvn);
	(*tt_data)->num_vlan = htons(num_vlan);

	tt_vlan = (*tt_data)->vlan_data;
	num_vlan = 0;
	hlist_for_each_entry(vlan, &orig_node->vlan_list, list) {
		vlan_entries = atomic_read(&vlan->tt.num_entries);
		if (vlan_entries < 1)
			continue;

		tt_vlan->vid = htons(vlan->vid);
		tt_vlan->crc = htonl(vlan->tt.crc);
		tt_vlan->reserved = 0;

		tt_vlan++;
		num_vlan++;
	}

	/* recalculate in case number of VLANs reduced */
	change_offset = struct_size(*tt_data, vlan_data, num_vlan);
	tvlv_len = *tt_len + change_offset;

	(*tt_data)->num_vlan = htons(num_vlan);

	tt_change_ptr = (u8 *)*tt_data + change_offset;
	*tt_change = (struct batadv_tvlv_tt_change *)tt_change_ptr;

out:
	spin_unlock_bh(&orig_node->vlan_list_lock);

	return tvlv_len;
}

/**
 * batadv_tt_prepare_tvlv_local_data() - allocate and prepare the TT TVLV for
 *  this node
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_data: uninitialised pointer to the address of the TVLV buffer
 * @tt_change: uninitialised pointer to the address of the area where the TT
 *  changes can be stored
 * @tt_len: pointer to the length to reserve to the tt_change. if -1 this
 *  function reserves the amount of space needed to send the entire local TT
 *  table. In case of success the value is updated with the real amount of
 *  reserved bytes
 *
 * Allocate the needed amount of memory for the entire TT TVLV and write its
 * header made up by one tvlv_tt_data object and a series of tvlv_tt_vlan_data
 * objects, one per active VLAN.
 *
 * Return: the size of the allocated buffer or 0 in case of failure.
 */
static u16
batadv_tt_prepare_tvlv_local_data(struct batadv_priv *bat_priv,
				  struct batadv_tvlv_tt_data **tt_data,
				  struct batadv_tvlv_tt_change **tt_change,
				  s32 *tt_len)
{
	struct batadv_tvlv_tt_vlan_data *tt_vlan;
	struct batadv_meshif_vlan *vlan;
	u16 total_entries = 0;
	size_t change_offset;
	u8 *tt_change_ptr;
	u16 num_vlan = 0;
	int vlan_entries;
	u16 sum_entries;
	u16 tvlv_len;

	spin_lock_bh(&bat_priv->meshif_vlan_list_lock);
	hlist_for_each_entry(vlan, &bat_priv->meshif_vlan_list, list) {
		vlan_entries = atomic_read(&vlan->tt.num_entries);

		if (check_add_overflow(vlan_entries, total_entries, &sum_entries)) {
			tvlv_len = 0;
			*tt_len = 0;
			goto out;
		}

		total_entries = sum_entries;
		num_vlan++;
	}

	change_offset = struct_size(*tt_data, vlan_data, num_vlan);

	/* if tt_len is negative, allocate the space needed by the full table */
	if (*tt_len < 0)
		*tt_len = batadv_tt_len(total_entries);

	if (check_add_overflow(*tt_len, change_offset, &tvlv_len)) {
		tvlv_len = 0;
		*tt_len = 0;
		goto out;
	}

	*tt_data = kmalloc(tvlv_len, GFP_ATOMIC);
	if (!*tt_data) {
		tvlv_len = 0;
		*tt_len = 0;
		goto out;
	}

	(*tt_data)->flags = BATADV_NO_FLAGS;
	(*tt_data)->ttvn = atomic_read(&bat_priv->tt.vn);
	(*tt_data)->num_vlan = htons(num_vlan);

	tt_vlan = (*tt_data)->vlan_data;
	num_vlan = 0;
	hlist_for_each_entry(vlan, &bat_priv->meshif_vlan_list, list) {
		vlan_entries = atomic_read(&vlan->tt.num_entries);
		if (vlan_entries < 1)
			continue;

		tt_vlan->vid = htons(vlan->vid);
		tt_vlan->crc = htonl(vlan->tt.crc);
		tt_vlan->reserved = 0;

		tt_vlan++;
		num_vlan++;
	}

	/* recalculate in case number of VLANs reduced */
	change_offset = struct_size(*tt_data, vlan_data, num_vlan);
	tvlv_len = *tt_len + change_offset;

	(*tt_data)->num_vlan = htons(num_vlan);

	tt_change_ptr = (u8 *)*tt_data + change_offset;
	*tt_change = (struct batadv_tvlv_tt_change *)tt_change_ptr;

out:
	spin_unlock_bh(&bat_priv->meshif_vlan_list_lock);

	return tvlv_len;
}

/**
 * batadv_tt_tvlv_container_update() - update the translation table tvlv
 *  container after local tt changes have been committed
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv)
{
	struct batadv_tvlv_tt_change *tt_change;
	struct batadv_tt_change_node *entry;
	struct batadv_tvlv_tt_data *tt_data;
	struct batadv_tt_change_node *safe;
	int tt_diff_entries_count = 0;
	int tt_diff_entries_num = 0;
	bool drop_changes = false;
	size_t tt_extra_len = 0;
	int tt_change_len = 0;
	int tt_diff_len;
	u16 tvlv_len;

	tt_diff_entries_num = READ_ONCE(bat_priv->tt.local_changes);
	tt_diff_len = batadv_tt_len(tt_diff_entries_num);

	/* if we have too many changes for one packet don't send any
	 * and wait for the tt table request so we can reply with the full
	 * (fragmented) table.
	 *
	 * The local change history should still be cleaned up so the next
	 * TT round can start again with a clean state.
	 */
	if (tt_diff_len > bat_priv->mesh_iface->mtu) {
		tt_diff_len = 0;
		tt_diff_entries_num = 0;
		drop_changes = true;
	}

	tvlv_len = batadv_tt_prepare_tvlv_local_data(bat_priv, &tt_data,
						     &tt_change, &tt_diff_len);
	if (!tvlv_len)
		return;

	tt_data->flags = BATADV_TT_OGM_DIFF;

	if (!drop_changes && tt_diff_len == 0)
		goto container_register;

	spin_lock_bh(&bat_priv->tt.changes_list_lock);
	WRITE_ONCE(bat_priv->tt.local_changes, 0);

	list_for_each_entry_safe(entry, safe, &bat_priv->tt.changes_list,
				 list) {
		if (tt_diff_entries_count < tt_diff_entries_num) {
			memcpy(tt_change + tt_diff_entries_count,
			       &entry->change,
			       sizeof(struct batadv_tvlv_tt_change));
			tt_diff_entries_count++;
		}
		list_del(&entry->list);
		kmem_cache_free(batadv_tt_change_cache, entry);
	}
	spin_unlock_bh(&bat_priv->tt.changes_list_lock);

	tt_extra_len = batadv_tt_len(tt_diff_entries_num -
				     tt_diff_entries_count);

	/* Keep the buffer for possible tt_request */
	spin_lock_bh(&bat_priv->tt.last_changeset_lock);
	kfree(bat_priv->tt.last_changeset);
	bat_priv->tt.last_changeset_len = 0;
	bat_priv->tt.last_changeset = NULL;
	tt_change_len = batadv_tt_len(tt_diff_entries_count);
	/* check whether this new OGM has no changes due to size problems */
	if (tt_diff_entries_count > 0) {
		tt_diff_len -= tt_extra_len;
		/* if kmalloc() fails we will reply with the full table
		 * instead of providing the diff
		 */
		bat_priv->tt.last_changeset = kzalloc(tt_diff_len, GFP_ATOMIC);
		if (bat_priv->tt.last_changeset) {
			memcpy(bat_priv->tt.last_changeset,
			       tt_change, tt_change_len);
			bat_priv->tt.last_changeset_len = tt_diff_len;
		}
	}
	spin_unlock_bh(&bat_priv->tt.last_changeset_lock);

	/* Remove extra packet space for OGM */
	tvlv_len -= tt_extra_len;
container_register:
	batadv_tvlv_container_register(bat_priv, BATADV_TVLV_TT, 1, tt_data,
				       tvlv_len);
	kfree(tt_data);
}

/**
 * batadv_tt_local_dump_entry() - Dump one TT local entry into a message
 * @msg :Netlink message to dump into
 * @portid: Port making netlink request
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the mesh interface information
 * @common: tt local & tt global common data
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_tt_local_dump_entry(struct sk_buff *msg, u32 portid,
			   struct netlink_callback *cb,
			   struct batadv_priv *bat_priv,
			   struct batadv_tt_common_entry *common)
{
	struct batadv_tt_local_entry *local;
	struct batadv_meshif_vlan *vlan;
	unsigned int last_seen_msecs;
	void *hdr;
	u32 crc;

	local = container_of(common, struct batadv_tt_local_entry, common);
	last_seen_msecs = jiffies_to_msecs(jiffies - local->last_seen);

	vlan = batadv_meshif_vlan_get(bat_priv, common->vid);
	if (!vlan)
		return 0;

	crc = vlan->tt.crc;

	batadv_meshif_vlan_put(vlan);

	hdr = genlmsg_put(msg, portid, cb->nlh->nlmsg_seq,
			  &batadv_netlink_family,  NLM_F_MULTI,
			  BATADV_CMD_GET_TRANSTABLE_LOCAL);
	if (!hdr)
		return -ENOBUFS;

	genl_dump_check_consistent(cb, hdr);

	if (nla_put(msg, BATADV_ATTR_TT_ADDRESS, ETH_ALEN, common->addr) ||
	    nla_put_u32(msg, BATADV_ATTR_TT_CRC32, crc) ||
	    nla_put_u16(msg, BATADV_ATTR_TT_VID, common->vid) ||
	    nla_put_u32(msg, BATADV_ATTR_TT_FLAGS, common->flags))
		goto nla_put_failure;

	if (!(common->flags & BATADV_TT_CLIENT_NOPURGE) &&
	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, last_seen_msecs))
		goto nla_put_failure;

	genlmsg_end(msg, hdr);
	return 0;

 nla_put_failure:
	genlmsg_cancel(msg, hdr);
	return -EMSGSIZE;
}

/**
 * batadv_tt_local_dump_bucket() - Dump one TT local bucket into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the mesh interface information
 * @hash: hash to dump
 * @bucket: bucket index to dump
 * @idx_s: Number of entries to skip
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_tt_local_dump_bucket(struct sk_buff *msg, u32 portid,
			    struct netlink_callback *cb,
			    struct batadv_priv *bat_priv,
			    struct batadv_hashtable *hash, unsigned int bucket,
			    int *idx_s)
{
	struct batadv_tt_common_entry *common;
	int idx = 0;

	spin_lock_bh(&hash->list_locks[bucket]);
	cb->seq = atomic_read(&hash->generation) << 1 | 1;

	hlist_for_each_entry(common, &hash->table[bucket], hash_entry) {
		if (idx++ < *idx_s)
			continue;

		if (batadv_tt_local_dump_entry(msg, portid, cb, bat_priv,
					       common)) {
			spin_unlock_bh(&hash->list_locks[bucket]);
			*idx_s = idx - 1;
			return -EMSGSIZE;
		}
	}
	spin_unlock_bh(&hash->list_locks[bucket]);

	*idx_s = 0;
	return 0;
}

/**
 * batadv_tt_local_dump() - Dump TT local entries into a message
 * @msg: Netlink message to dump into
 * @cb: Parameters from query
 *
 * Return: Error code, or 0 on success
 */
int batadv_tt_local_dump(struct sk_buff *msg, struct netlink_callback *cb)
{
	struct batadv_hard_iface *primary_if = NULL;
	int portid = NETLINK_CB(cb->skb).portid;
	struct net_device *mesh_iface;
	struct batadv_hashtable *hash;
	struct batadv_priv *bat_priv;
	int bucket = cb->args[0];
	int idx = cb->args[1];
	int ret;

	mesh_iface = batadv_netlink_get_meshif(cb);
	if (IS_ERR(mesh_iface))
		return PTR_ERR(mesh_iface);

	bat_priv = netdev_priv(mesh_iface);

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
		ret = -ENOENT;
		goto out;
	}

	hash = bat_priv->tt.local_hash;

	while (bucket < hash->size) {
		if (batadv_tt_local_dump_bucket(msg, portid, cb, bat_priv,
						hash, bucket, &idx))
			break;

		bucket++;
	}

	ret = msg->len;

 out:
	batadv_hardif_put(primary_if);
	dev_put(mesh_iface);

	cb->args[0] = bucket;
	cb->args[1] = idx;

	return ret;
}

/**
 * batadv_tt_local_set_pending() - mark a local TT entry as pending removal
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_local_entry: local TT entry to mark
 * @flags: TT change flags to announce together with the pending removal
 * @message: debug message describing the reason for the change
 *
 * Schedule the TT change announcement and set BATADV_TT_CLIENT_PENDING on the
 * entry. The entry is kept in the local table until the next TTVN increment
 * so that a consistency-check response can still be answered.
 */
static void
batadv_tt_local_set_pending(struct batadv_priv *bat_priv,
			    struct batadv_tt_local_entry *tt_local_entry,
			    u16 flags, const char *message)
{
	batadv_tt_local_event(bat_priv, tt_local_entry, flags);

	/* The local client has to be marked as "pending to be removed" but has
	 * to be kept in the table in order to send it in a full table
	 * response issued before the net ttvn increment (consistency check)
	 */
	tt_local_entry->common.flags |= BATADV_TT_CLIENT_PENDING;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Local tt entry (%pM, vid: %d) pending to be removed: %s\n",
		   tt_local_entry->common.addr,
		   batadv_print_vid(tt_local_entry->common.vid), message);
}

/**
 * batadv_tt_local_remove() - logically remove an entry from the local table
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the MAC address of the client to remove
 * @vid: VLAN identifier
 * @message: message to append to the log on deletion
 * @roaming: true if the deletion is due to a roaming event
 *
 * Return: the flags assigned to the local entry before being deleted
 */
u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr,
			   unsigned short vid, const char *message,
			   bool roaming)
{
	struct batadv_tt_local_entry *tt_removed_entry;
	struct batadv_tt_local_entry *tt_local_entry;
	struct hlist_node *tt_removed_node;
	u16 curr_flags = BATADV_NO_FLAGS;
	u16 flags;

	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid);
	if (!tt_local_entry)
		goto out;

	curr_flags = tt_local_entry->common.flags;

	flags = BATADV_TT_CLIENT_DEL;
	/* 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;
	}

	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, BATADV_TT_CLIENT_DEL);

	tt_removed_node = batadv_hash_remove(bat_priv->tt.local_hash,
					     batadv_compare_tt,
					     batadv_choose_tt,
					     &tt_local_entry->common);
	if (!tt_removed_node)
		goto out;

	/* drop reference of remove hash entry */
	tt_removed_entry = hlist_entry(tt_removed_node,
				       struct batadv_tt_local_entry,
				       common.hash_entry);
	batadv_tt_local_entry_put(tt_removed_entry);

out:
	batadv_tt_local_entry_put(tt_local_entry);

	return curr_flags;
}

/**
 * batadv_tt_local_purge_list() - purge inactive tt local entries
 * @bat_priv: the bat priv with all the mesh interface information
 * @head: pointer to the list containing the local tt entries
 * @timeout: parameter deciding whether a given tt local entry is considered
 *  inactive or not
 */
static void batadv_tt_local_purge_list(struct batadv_priv *bat_priv,
				       struct hlist_head *head,
				       int timeout)
{
	struct batadv_tt_common_entry *tt_common_entry;
	struct batadv_tt_local_entry *tt_local_entry;
	struct hlist_node *node_tmp;

	hlist_for_each_entry_safe(tt_common_entry, node_tmp, head,
				  hash_entry) {
		tt_local_entry = container_of(tt_common_entry,
					      struct batadv_tt_local_entry,
					      common);
		if (tt_local_entry->common.flags & BATADV_TT_CLIENT_NOPURGE)
			continue;

		/* entry already marked for deletion */
		if (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING)
			continue;

		if (!batadv_has_timed_out(tt_local_entry->last_seen, timeout))
			continue;

		batadv_tt_local_set_pending(bat_priv, tt_local_entry,
					    BATADV_TT_CLIENT_DEL, "timed out");
	}
}

/**
 * batadv_tt_local_purge() - purge inactive tt local entries
 * @bat_priv: the bat priv with all the mesh interface information
 * @timeout: parameter deciding whether a given tt local entry is considered
 *  inactive or not
 */
static void batadv_tt_local_purge(struct batadv_priv *bat_priv,
				  int timeout)
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_hashtable *hash = bat_priv->tt.local_hash;
	struct hlist_head *head;
	u32 i;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		list_lock = &hash->list_locks[i];

		spin_lock_bh(list_lock);
		batadv_tt_local_purge_list(bat_priv, head, timeout);
		spin_unlock_bh(list_lock);
	}
}

/**
 * batadv_tt_local_table_free() - release the local translation table
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Drop every entry of the local TT hash, free their references and finally
 * release the hashtable itself.
 */
static void batadv_tt_local_table_free(struct batadv_priv *bat_priv)
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_tt_common_entry *tt_common_entry;
	struct batadv_tt_local_entry *tt_local;
	struct batadv_hashtable *hash;
	struct hlist_node *node_tmp;
	struct hlist_head *head;
	u32 i;

	if (!bat_priv->tt.local_hash)
		return;

	hash = bat_priv->tt.local_hash;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		list_lock = &hash->list_locks[i];

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(tt_common_entry, node_tmp,
					  head, hash_entry) {
			hlist_del_rcu(&tt_common_entry->hash_entry);
			tt_local = container_of(tt_common_entry,
						struct batadv_tt_local_entry,
						common);

			batadv_tt_local_entry_put(tt_local);
		}
		spin_unlock_bh(list_lock);
	}

	batadv_hash_destroy(hash);

	bat_priv->tt.local_hash = NULL;
}

/**
 * batadv_tt_global_init() - allocate and initialise the global translation
 *  table
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Return: 0 on success or -ENOMEM in case of allocation failure
 */
static int batadv_tt_global_init(struct batadv_priv *bat_priv)
{
	if (bat_priv->tt.global_hash)
		return 0;

	bat_priv->tt.global_hash = batadv_hash_new(1024);

	if (!bat_priv->tt.global_hash)
		return -ENOMEM;

	batadv_hash_set_lock_class(bat_priv->tt.global_hash,
				   &batadv_tt_global_hash_lock_class_key);

	return 0;
}

/**
 * batadv_tt_changes_list_free() - drop all pending local TT changes
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Discard every queued local TT change and reset the pending change counter.
 */
static void batadv_tt_changes_list_free(struct batadv_priv *bat_priv)
{
	struct batadv_tt_change_node *entry;
	struct batadv_tt_change_node *safe;

	spin_lock_bh(&bat_priv->tt.changes_list_lock);

	list_for_each_entry_safe(entry, safe, &bat_priv->tt.changes_list,
				 list) {
		list_del(&entry->list);
		kmem_cache_free(batadv_tt_change_cache, entry);
	}

	WRITE_ONCE(bat_priv->tt.local_changes, 0);
	spin_unlock_bh(&bat_priv->tt.changes_list_lock);
}

/**
 * batadv_tt_global_orig_entry_find() - find a TT orig_list_entry
 * @entry: the TT global entry where the orig_list_entry has to be
 *  extracted from
 * @orig_node: the originator for which the orig_list_entry has to be found
 *
 * retrieve the orig_tt_list_entry belonging to orig_node from the
 * batadv_tt_global_entry list
 *
 * Return: it with an increased refcounter, NULL if not found
 */
static struct batadv_tt_orig_list_entry *
batadv_tt_global_orig_entry_find(const struct batadv_tt_global_entry *entry,
				 const struct batadv_orig_node *orig_node)
{
	struct batadv_tt_orig_list_entry *orig_entry = NULL;
	struct batadv_tt_orig_list_entry *tmp_orig_entry;
	const struct hlist_head *head;

	rcu_read_lock();
	head = &entry->orig_list;
	hlist_for_each_entry_rcu(tmp_orig_entry, head, list) {
		if (tmp_orig_entry->orig_node != orig_node)
			continue;
		if (!kref_get_unless_zero(&tmp_orig_entry->refcount))
			continue;

		orig_entry = tmp_orig_entry;
		break;
	}
	rcu_read_unlock();

	return orig_entry;
}

/**
 * batadv_tt_global_entry_has_orig() - check if a TT global entry is also
 *  handled by a given originator
 * @entry: the TT global entry to check
 * @orig_node: the originator to search in the list
 * @flags: a pointer to store TT flags for the given @entry received
 *  from @orig_node
 *
 * find out if an orig_node is already in the list of a tt_global_entry.
 *
 * Return: true if found, false otherwise
 */
static bool
batadv_tt_global_entry_has_orig(const struct batadv_tt_global_entry *entry,
				const struct batadv_orig_node *orig_node,
				u8 *flags)
{
	struct batadv_tt_orig_list_entry *orig_entry;
	bool found = false;

	orig_entry = batadv_tt_global_orig_entry_find(entry, orig_node);
	if (orig_entry) {
		found = true;

		if (flags)
			*flags = orig_entry->flags;

		batadv_tt_orig_list_entry_put(orig_entry);
	}

	return found;
}

/**
 * batadv_tt_global_sync_flags() - update TT sync flags
 * @tt_global: the TT global entry to update sync flags in
 *
 * Updates the sync flag bits in the tt_global flag attribute with a logical
 * OR of all sync flags from any of its TT orig entries.
 */
static void
batadv_tt_global_sync_flags(struct batadv_tt_global_entry *tt_global)
{
	struct batadv_tt_orig_list_entry *orig_entry;
	const struct hlist_head *head;
	u16 flags = BATADV_NO_FLAGS;

	rcu_read_lock();
	head = &tt_global->orig_list;
	hlist_for_each_entry_rcu(orig_entry, head, list)
		flags |= orig_entry->flags;
	rcu_read_unlock();

	flags |= tt_global->common.flags & (~BATADV_TT_SYNC_MASK);
	tt_global->common.flags = flags;
}

/**
 * batadv_tt_global_orig_entry_add() - add or update a TT orig entry
 * @tt_global: the TT global entry to add an orig entry in
 * @orig_node: the originator to add an orig entry for
 * @ttvn: translation table version number of this changeset
 * @flags: TT sync flags
 */
static void
batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
				struct batadv_orig_node *orig_node, int ttvn,
				u8 flags)
{
	struct batadv_tt_orig_list_entry *orig_entry;

	spin_lock_bh(&tt_global->list_lock);

	orig_entry = batadv_tt_global_orig_entry_find(tt_global, orig_node);
	if (orig_entry) {
		/* refresh the ttvn: the current value could be a bogus one that
		 * was added during a "temporary client detection"
		 */
		orig_entry->ttvn = ttvn;
		orig_entry->flags = flags;
		goto sync_flags;
	}

	orig_entry = kmem_cache_zalloc(batadv_tt_orig_cache, GFP_ATOMIC);
	if (!orig_entry)
		goto out;

	INIT_HLIST_NODE(&orig_entry->list);
	kref_get(&orig_node->refcount);
	batadv_tt_global_size_inc(orig_node, tt_global->common.vid);
	orig_entry->orig_node = orig_node;
	orig_entry->ttvn = ttvn;
	orig_entry->flags = flags;
	kref_init(&orig_entry->refcount);

	kref_get(&orig_entry->refcount);
	hlist_add_head_rcu(&orig_entry->list,
			   &tt_global->orig_list);
	atomic_inc(&tt_global->orig_list_count);

sync_flags:
	batadv_tt_global_sync_flags(tt_global);
out:
	batadv_tt_orig_list_entry_put(orig_entry);

	spin_unlock_bh(&tt_global->list_lock);
}

/**
 * batadv_tt_global_add() - add a new TT global entry or update an existing one
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: the originator announcing the client
 * @tt_addr: the mac address of the non-mesh client
 * @vid: VLAN identifier
 * @flags: TT flags that have to be set for this non-mesh client
 * @ttvn: the tt version number ever announcing this non-mesh client
 *
 * Add a new TT global entry for the given originator. If the entry already
 * exists add a new reference to the given originator (a global entry can have
 * references to multiple originators) and adjust the flags attribute to reflect
 * the function argument.
 * If a TT local entry exists for this non-mesh client remove it.
 *
 * The caller must hold the orig_node refcount.
 *
 * Return: true if the new entry has been added, false otherwise
 */
static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
				 struct batadv_orig_node *orig_node,
				 const unsigned char *tt_addr,
				 unsigned short vid, u16 flags, u8 ttvn)
{
	struct batadv_tt_global_entry *tt_global_entry;
	struct batadv_tt_local_entry *tt_local_entry;
	struct batadv_tt_common_entry *common;
	bool ret = false;
	u16 local_flags;
	int hash_added;

	/* ignore global entries from backbone nodes */
	if (batadv_bla_is_backbone_gw_orig(bat_priv, orig_node->orig, vid))
		return true;

	tt_global_entry = batadv_tt_global_hash_find(bat_priv, tt_addr, vid);
	tt_local_entry = batadv_tt_local_hash_find(bat_priv, tt_addr, vid);

	/* 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 = kmem_cache_zalloc(batadv_tg_cache,
						    GFP_ATOMIC);
		if (!tt_global_entry)
			goto out;

		common = &tt_global_entry->common;
		ether_addr_copy(common->addr, tt_addr);
		common->vid = vid;

		if (!is_multicast_ether_addr(common->addr))
			common->flags = flags & (~BATADV_TT_SYNC_MASK);

		tt_global_entry->roam_at = 0;
		/* node must store current time in case of roaming. This is
		 * needed to purge this entry out on timeout (if nobody claims
		 * it)
		 */
		if (flags & BATADV_TT_CLIENT_ROAM)
			tt_global_entry->roam_at = jiffies;
		kref_init(&common->refcount);
		common->added_at = jiffies;

		INIT_HLIST_HEAD(&tt_global_entry->orig_list);
		atomic_set(&tt_global_entry->orig_list_count, 0);
		spin_lock_init(&tt_global_entry->list_lock);

		kref_get(&common->refcount);
		hash_added = batadv_hash_add(bat_priv->tt.global_hash,
					     batadv_compare_tt,
					     batadv_choose_tt, common,
					     &common->hash_entry);

		if (unlikely(hash_added != 0)) {
			/* remove the reference for the hash */
			batadv_tt_global_entry_put(tt_global_entry);
			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 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) {
			if (!(common->flags & BATADV_TT_CLIENT_TEMP))
				goto out;
			if (batadv_tt_global_entry_has_orig(tt_global_entry,
							    orig_node, NULL))
				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. Also,
		 * remove the previous temporary orig node and re-add it
		 * if required. If the orig entry changed, the new one which
		 * is a non-temporary entry is preferred.
		 */
		if (common->flags & BATADV_TT_CLIENT_TEMP) {
			batadv_tt_global_del_orig_list(tt_global_entry);
			common->flags &= ~BATADV_TT_CLIENT_TEMP;
		}

		/* the change can carry possible "attribute" flags like the
		 * TT_CLIENT_TEMP, therefore they have to be copied in the
		 * client entry
		 */
		if (!is_multicast_ether_addr(common->addr))
			common->flags |= flags & (~BATADV_TT_SYNC_MASK);

		/* If there is the BATADV_TT_CLIENT_ROAM flag set, there is only
		 * one originator left in the list and we previously received a
		 * delete + roaming change for this originator.
		 *
		 * We should first delete the old originator before adding the
		 * new one.
		 */
		if (common->flags & BATADV_TT_CLIENT_ROAM) {
			batadv_tt_global_del_orig_list(tt_global_entry);
			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,
					flags & BATADV_TT_SYNC_MASK);

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Creating new global tt entry: %pM (vid: %d, via %pM)\n",
		   common->addr, batadv_print_vid(common->vid),
		   orig_node->orig);
	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, vid,
					     "global tt received",
					     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:
	batadv_tt_global_entry_put(tt_global_entry);
	batadv_tt_local_entry_put(tt_local_entry);
	return ret;
}

/**
 * batadv_transtable_best_orig() - Get best originator list entry from tt entry
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_global_entry: global translation table entry to be analyzed
 *
 * This function assumes the caller holds rcu_read_lock().
 * Return: best originator list entry or NULL on errors.
 */
static struct batadv_tt_orig_list_entry *
batadv_transtable_best_orig(struct batadv_priv *bat_priv,
			    struct batadv_tt_global_entry *tt_global_entry)
{
	struct batadv_tt_orig_list_entry *best_entry = NULL;
	struct batadv_algo_ops *bao = bat_priv->algo_ops;
	struct batadv_neigh_node *best_router = NULL;
	struct batadv_tt_orig_list_entry *orig_entry;
	struct batadv_neigh_node *router;
	struct hlist_head *head;

	head = &tt_global_entry->orig_list;
	hlist_for_each_entry_rcu(orig_entry, head, list) {
		router = batadv_orig_router_get(orig_entry->orig_node,
						BATADV_IF_DEFAULT);
		if (!router)
			continue;

		if (best_router &&
		    bao->neigh.cmp(router, BATADV_IF_DEFAULT, best_router,
				   BATADV_IF_DEFAULT) <= 0) {
			batadv_neigh_node_put(router);
			continue;
		}

		/* release the refcount for the "old" best */
		batadv_neigh_node_put(best_router);

		best_entry = orig_entry;
		best_router = router;
	}

	batadv_neigh_node_put(best_router);

	return best_entry;
}

/**
 * batadv_tt_global_dump_subentry() - Dump all TT local entries into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @common: tt local & tt global common data
 * @orig: Originator node announcing a non-mesh client
 * @best: Is the best originator for the TT entry
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_tt_global_dump_subentry(struct sk_buff *msg, u32 portid, u32 seq,
			       struct batadv_tt_common_entry *common,
			       struct batadv_tt_orig_list_entry *orig,
			       bool best)
{
	u16 flags = (common->flags & (~BATADV_TT_SYNC_MASK)) | orig->flags;
	struct batadv_orig_node_vlan *vlan;
	u8 last_ttvn;
	void *hdr;
	u32 crc;

	vlan = batadv_orig_node_vlan_get(orig->orig_node,
					 common->vid);
	if (!vlan)
		return 0;

	crc = vlan->tt.crc;

	batadv_orig_node_vlan_put(vlan);

	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
			  NLM_F_MULTI,
			  BATADV_CMD_GET_TRANSTABLE_GLOBAL);
	if (!hdr)
		return -ENOBUFS;

	last_ttvn = READ_ONCE(orig->orig_node->last_ttvn);

	if (nla_put(msg, BATADV_ATTR_TT_ADDRESS, ETH_ALEN, common->addr) ||
	    nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN,
		    orig->orig_node->orig) ||
	    nla_put_u8(msg, BATADV_ATTR_TT_TTVN, orig->ttvn) ||
	    nla_put_u8(msg, BATADV_ATTR_TT_LAST_TTVN, last_ttvn) ||
	    nla_put_u32(msg, BATADV_ATTR_TT_CRC32, crc) ||
	    nla_put_u16(msg, BATADV_ATTR_TT_VID, common->vid) ||
	    nla_put_u32(msg, BATADV_ATTR_TT_FLAGS, flags))
		goto nla_put_failure;

	if (best && nla_put_flag(msg, BATADV_ATTR_FLAG_BEST))
		goto nla_put_failure;

	genlmsg_end(msg, hdr);
	return 0;

 nla_put_failure:
	genlmsg_cancel(msg, hdr);
	return -EMSGSIZE;
}

/**
 * batadv_tt_global_dump_entry() - Dump one TT global entry into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @bat_priv: The bat priv with all the mesh interface information
 * @common: tt local & tt global common data
 * @sub_s: Number of entries to skip
 *
 * This function assumes the caller holds rcu_read_lock().
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_tt_global_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
			    struct batadv_priv *bat_priv,
			    struct batadv_tt_common_entry *common, int *sub_s)
{
	struct batadv_tt_orig_list_entry *orig_entry;
	struct batadv_tt_orig_list_entry *best_entry;
	struct batadv_tt_global_entry *global;
	struct hlist_head *head;
	int sub = 0;
	bool best;

	global = container_of(common, struct batadv_tt_global_entry, common);
	best_entry = batadv_transtable_best_orig(bat_priv, global);
	head = &global->orig_list;

	hlist_for_each_entry_rcu(orig_entry, head, list) {
		if (sub++ < *sub_s)
			continue;

		best = (orig_entry == best_entry);

		if (batadv_tt_global_dump_subentry(msg, portid, seq, common,
						   orig_entry, best)) {
			*sub_s = sub - 1;
			return -EMSGSIZE;
		}
	}

	*sub_s = 0;
	return 0;
}

/**
 * batadv_tt_global_dump_bucket() - Dump one TT local bucket into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @bat_priv: The bat priv with all the mesh interface information
 * @head: Pointer to the list containing the global tt entries
 * @idx_s: Number of entries to skip
 * @sub: Number of entries to skip
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_tt_global_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
			     struct batadv_priv *bat_priv,
			     struct hlist_head *head, int *idx_s, int *sub)
{
	struct batadv_tt_common_entry *common;
	int idx = 0;

	rcu_read_lock();
	hlist_for_each_entry_rcu(common, head, hash_entry) {
		if (idx++ < *idx_s)
			continue;

		if (batadv_tt_global_dump_entry(msg, portid, seq, bat_priv,
						common, sub)) {
			rcu_read_unlock();
			*idx_s = idx - 1;
			return -EMSGSIZE;
		}
	}
	rcu_read_unlock();

	*idx_s = 0;
	*sub = 0;
	return 0;
}

/**
 * batadv_tt_global_dump() -  Dump TT global entries into a message
 * @msg: Netlink message to dump into
 * @cb: Parameters from query
 *
 * Return: Error code, or length of message on success
 */
int batadv_tt_global_dump(struct sk_buff *msg, struct netlink_callback *cb)
{
	struct batadv_hard_iface *primary_if = NULL;
	int portid = NETLINK_CB(cb->skb).portid;
	struct net_device *mesh_iface;
	struct batadv_hashtable *hash;
	struct batadv_priv *bat_priv;
	int bucket = cb->args[0];
	struct hlist_head *head;
	int idx = cb->args[1];
	int sub = cb->args[2];
	int ret;

	mesh_iface = batadv_netlink_get_meshif(cb);
	if (IS_ERR(mesh_iface))
		return PTR_ERR(mesh_iface);

	bat_priv = netdev_priv(mesh_iface);

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
		ret = -ENOENT;
		goto out;
	}

	hash = bat_priv->tt.global_hash;

	while (bucket < hash->size) {
		head = &hash->table[bucket];

		if (batadv_tt_global_dump_bucket(msg, portid,
						 cb->nlh->nlmsg_seq, bat_priv,
						 head, &idx, &sub))
			break;

		bucket++;
	}

	ret = msg->len;

 out:
	batadv_hardif_put(primary_if);
	dev_put(mesh_iface);

	cb->args[0] = bucket;
	cb->args[1] = idx;
	cb->args[2] = sub;

	return ret;
}

/**
 * _batadv_tt_global_del_orig_entry() - remove and free an orig_entry
 * @tt_global_entry: the global entry to remove the orig_entry from
 * @orig_entry: the orig entry to remove and free
 *
 * Remove an orig_entry from its list in the given tt_global_entry and
 * free this orig_entry afterwards.
 *
 * Caller must hold tt_global_entry->list_lock and ensure orig_entry->list is
 * part of a list.
 */
static void
_batadv_tt_global_del_orig_entry(struct batadv_tt_global_entry *tt_global_entry,
				 struct batadv_tt_orig_list_entry *orig_entry)
{
	lockdep_assert_held(&tt_global_entry->list_lock);

	batadv_tt_global_size_dec(orig_entry->orig_node,
				  tt_global_entry->common.vid);
	atomic_dec(&tt_global_entry->orig_list_count);
	/* requires holding tt_global_entry->list_lock and orig_entry->list
	 * being part of a list
	 */
	hlist_del_rcu(&orig_entry->list);
	batadv_tt_orig_list_entry_put(orig_entry);
}

/**
 * batadv_tt_global_del_orig_list() - drop every orig_list_entry of a global
 *  TT entry
 * @tt_global_entry: the global TT entry to clear
 */
static void
batadv_tt_global_del_orig_list(struct batadv_tt_global_entry *tt_global_entry)
{
	struct batadv_tt_orig_list_entry *orig_entry;
	struct hlist_head *head;
	struct hlist_node *safe;

	spin_lock_bh(&tt_global_entry->list_lock);
	head = &tt_global_entry->orig_list;
	hlist_for_each_entry_safe(orig_entry, safe, head, list)
		_batadv_tt_global_del_orig_entry(tt_global_entry, orig_entry);
	spin_unlock_bh(&tt_global_entry->list_lock);
}

/**
 * batadv_tt_global_del_orig_node() - remove orig_node from a global tt entry
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_global_entry: the global entry to remove the orig_node from
 * @orig_node: the originator announcing the client
 * @message: message to append to the log on deletion
 *
 * Remove the given orig_node and its according orig_entry from the given
 * global tt entry.
 */
static void
batadv_tt_global_del_orig_node(struct batadv_priv *bat_priv,
			       struct batadv_tt_global_entry *tt_global_entry,
			       struct batadv_orig_node *orig_node,
			       const char *message)
{
	struct batadv_tt_orig_list_entry *orig_entry;
	struct hlist_head *head;
	struct hlist_node *safe;
	unsigned short vid;

	spin_lock_bh(&tt_global_entry->list_lock);
	head = &tt_global_entry->orig_list;
	hlist_for_each_entry_safe(orig_entry, safe, head, list) {
		if (orig_entry->orig_node == orig_node) {
			vid = tt_global_entry->common.vid;
			batadv_dbg(BATADV_DBG_TT, bat_priv,
				   "Deleting %pM from global tt entry %pM (vid: %d): %s\n",
				   orig_node->orig,
				   tt_global_entry->common.addr,
				   batadv_print_vid(vid), message);
			_batadv_tt_global_del_orig_entry(tt_global_entry,
							 orig_entry);
		}
	}
	spin_unlock_bh(&tt_global_entry->list_lock);
}

/**
 * batadv_tt_global_del_roaming() - remove a roaming client from a global TT
 *  entry
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_global_entry: the global TT entry of the roaming client
 * @orig_node: the originator that the client has roamed away from
 * @message: debug message describing the reason for the change
 *
 * If @orig_node was the last announced source for the client, mark the entry
 * for roaming so it can be cleaned up after the roaming timer expires.
 * Otherwise simply remove the orig_node entry from the announcer list.
 */
static void
batadv_tt_global_del_roaming(struct batadv_priv *bat_priv,
			     struct batadv_tt_global_entry *tt_global_entry,
			     struct batadv_orig_node *orig_node,
			     const char *message)
{
	struct batadv_tt_orig_list_entry *orig_entry;
	struct hlist_head *head;
	bool last_entry = true;

	/* no local entry exists, case 1:
	 * Check if this is the last one or if other entries exist.
	 */

	rcu_read_lock();
	head = &tt_global_entry->orig_list;
	hlist_for_each_entry_rcu(orig_entry, head, list) {
		if (orig_entry->orig_node != orig_node) {
			last_entry = false;
			break;
		}
	}
	rcu_read_unlock();

	if (last_entry) {
		/* its the last one, mark for roaming. */
		tt_global_entry->common.flags |= BATADV_TT_CLIENT_ROAM;
		tt_global_entry->roam_at = jiffies;
	} else {
		/* there is another entry, we can simply delete this
		 * one and can still use the other one.
		 */
		batadv_tt_global_del_orig_node(bat_priv, tt_global_entry,
					       orig_node, message);
	}
}

/**
 * batadv_tt_global_del() - remove a client from the global table
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: an originator serving this client
 * @addr: the mac address of the client
 * @vid: VLAN identifier
 * @message: a message explaining the reason for deleting the client to print
 *  for debugging purpose
 * @roaming: true if the deletion has been triggered by a roaming event
 */
static void batadv_tt_global_del(struct batadv_priv *bat_priv,
				 struct batadv_orig_node *orig_node,
				 const unsigned char *addr, unsigned short vid,
				 const char *message, bool roaming)
{
	struct batadv_tt_local_entry *local_entry = NULL;
	struct batadv_tt_global_entry *tt_global_entry;

	tt_global_entry = batadv_tt_global_hash_find(bat_priv, addr, vid);
	if (!tt_global_entry)
		goto out;

	if (!roaming) {
		batadv_tt_global_del_orig_node(bat_priv, tt_global_entry,
					       orig_node, message);

		if (hlist_empty(&tt_global_entry->orig_list))
			batadv_tt_global_free(bat_priv, tt_global_entry,
					      message);

		goto out;
	}

	/* if we are deleting a global entry due to a roam
	 * event, there are two possibilities:
	 * 1) the client roamed from node A to node B => if there
	 *    is only one originator left for this client, we mark
	 *    it with BATADV_TT_CLIENT_ROAM, we start a timer and we
	 *    wait for node B to claim it. In case of timeout
	 *    the entry is purged.
	 *
	 *    If there are other originators left, we directly delete
	 *    the originator.
	 * 2) the client roamed to us => we can directly delete
	 *    the global entry, since it is useless now.
	 */
	local_entry = batadv_tt_local_hash_find(bat_priv,
						tt_global_entry->common.addr,
						vid);
	if (local_entry) {
		/* local entry exists, case 2: client roamed to us. */
		batadv_tt_global_del_orig_list(tt_global_entry);
		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,
					     orig_node, message);
	}

out:
	batadv_tt_global_entry_put(tt_global_entry);
	batadv_tt_local_entry_put(local_entry);
}

/**
 * batadv_tt_global_del_orig() - remove all the TT global entries belonging to
 *  the given originator matching the provided vid
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: the originator owning the entries to remove
 * @match_vid: the VLAN identifier to match. If negative all the entries will be
 *  removed
 * @message: debug message to print as "reason"
 */
void batadv_tt_global_del_orig(struct batadv_priv *bat_priv,
			       struct batadv_orig_node *orig_node,
			       s32 match_vid,
			       const char *message)
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_hashtable *hash = bat_priv->tt.global_hash;
	struct batadv_tt_common_entry *tt_common_entry;
	struct batadv_tt_global_entry *tt_global;
	struct hlist_node *safe;
	struct hlist_head *head;
	unsigned short vid;
	u32 i;

	if (!hash)
		return;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		list_lock = &hash->list_locks[i];

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(tt_common_entry, safe,
					  head, hash_entry) {
			/* remove only matching entries */
			if (match_vid >= 0 && tt_common_entry->vid != match_vid)
				continue;

			tt_global = container_of(tt_common_entry,
						 struct batadv_tt_global_entry,
						 common);

			batadv_tt_global_del_orig_node(bat_priv, tt_global,
						       orig_node, message);

			if (hlist_empty(&tt_global->orig_list)) {
				vid = tt_global->common.vid;
				batadv_dbg(BATADV_DBG_TT, bat_priv,
					   "Deleting global tt entry %pM (vid: %d): %s\n",
					   tt_global->common.addr,
					   batadv_print_vid(vid), message);
				hlist_del_rcu(&tt_common_entry->hash_entry);
				batadv_tt_global_entry_put(tt_global);
			}
		}
		spin_unlock_bh(list_lock);
	}
	clear_bit(BATADV_ORIG_CAPA_HAS_TT, &orig_node->capa_initialized);
}

/**
 * batadv_tt_global_to_purge() - check whether a global TT entry has to be
 *  purged
 * @tt_global: global TT entry under consideration
 * @msg: storage for a pointer to a human readable reason on return
 *
 * Return: true if the entry should be purged because its roaming or temporary
 *  timer has elapsed; false otherwise
 */
static bool batadv_tt_global_to_purge(struct batadv_tt_global_entry *tt_global,
				      char **msg)
{
	unsigned long roam_timeout = BATADV_TT_CLIENT_ROAM_TIMEOUT;
	unsigned long temp_timeout = BATADV_TT_CLIENT_TEMP_TIMEOUT;
	bool purge = false;

	if ((tt_global->common.flags & BATADV_TT_CLIENT_ROAM) &&
	    batadv_has_timed_out(tt_global->roam_at, roam_timeout)) {
		purge = true;
		*msg = "Roaming timeout\n";
	}

	if ((tt_global->common.flags & BATADV_TT_CLIENT_TEMP) &&
	    batadv_has_timed_out(tt_global->common.added_at, temp_timeout)) {
		purge = true;
		*msg = "Temporary client timeout\n";
	}

	return purge;
}

/**
 * batadv_tt_global_purge() - purge expired global translation table entries
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Iterate over the global translation table and drop every entry that the
 * roaming or temporary timer has expired for.
 */
static void batadv_tt_global_purge(struct batadv_priv *bat_priv)
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_hashtable *hash = bat_priv->tt.global_hash;
	struct batadv_tt_common_entry *tt_common;
	struct batadv_tt_global_entry *tt_global;
	struct hlist_node *node_tmp;
	struct hlist_head *head;
	char *msg = NULL;
	u32 i;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		list_lock = &hash->list_locks[i];

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(tt_common, node_tmp, head,
					  hash_entry) {
			tt_global = container_of(tt_common,
						 struct batadv_tt_global_entry,
						 common);

			if (!batadv_tt_global_to_purge(tt_global, &msg))
				continue;

			batadv_dbg(BATADV_DBG_TT, bat_priv,
				   "Deleting global tt entry %pM (vid: %d): %s\n",
				   tt_global->common.addr,
				   batadv_print_vid(tt_global->common.vid),
				   msg);

			hlist_del_rcu(&tt_common->hash_entry);

			batadv_tt_global_entry_put(tt_global);
		}
		spin_unlock_bh(list_lock);
	}
}

/**
 * batadv_tt_global_table_free() - release the global translation table
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Drop every entry of the global TT hash, free their references and finally
 * release the hashtable itself.
 */
static void batadv_tt_global_table_free(struct batadv_priv *bat_priv)
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_tt_common_entry *tt_common_entry;
	struct batadv_tt_global_entry *tt_global;
	struct batadv_hashtable *hash;
	struct hlist_node *node_tmp;
	struct hlist_head *head;
	u32 i;

	if (!bat_priv->tt.global_hash)
		return;

	hash = bat_priv->tt.global_hash;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		list_lock = &hash->list_locks[i];

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(tt_common_entry, node_tmp,
					  head, hash_entry) {
			hlist_del_rcu(&tt_common_entry->hash_entry);
			tt_global = container_of(tt_common_entry,
						 struct batadv_tt_global_entry,
						 common);
			batadv_tt_global_entry_put(tt_global);
		}
		spin_unlock_bh(list_lock);
	}

	batadv_hash_destroy(hash);

	bat_priv->tt.global_hash = NULL;
}

/**
 * _batadv_is_ap_isolated() - check whether two clients are AP-isolated from
 *  each other
 * @tt_local_entry: local TT entry of the sending client
 * @tt_global_entry: global TT entry of the destination client
 *
 * Return: true if traffic between the two clients should be dropped because
 *  either both are WiFi clients or both carry the ISOLATION flag; false
 *  otherwise
 */
static bool
_batadv_is_ap_isolated(struct batadv_tt_local_entry *tt_local_entry,
		       struct batadv_tt_global_entry *tt_global_entry)
{
	if (tt_local_entry->common.flags & BATADV_TT_CLIENT_WIFI &&
	    tt_global_entry->common.flags & BATADV_TT_CLIENT_WIFI)
		return true;

	/* check if the two clients are marked as isolated */
	if (tt_local_entry->common.flags & BATADV_TT_CLIENT_ISOLA &&
	    tt_global_entry->common.flags & BATADV_TT_CLIENT_ISOLA)
		return true;

	return false;
}

/**
 * batadv_transtable_search() - get the mesh destination for a given client
 * @bat_priv: the bat priv with all the mesh interface information
 * @src: mac address of the source client
 * @addr: mac address of the destination client
 * @vid: VLAN identifier
 *
 * Return: a pointer to the originator that was selected as destination in the
 * mesh for contacting the client 'addr', NULL otherwise.
 * In case of multiple originators serving the same client, the function returns
 * the best one (best in terms of metric towards the destination node).
 *
 * If the two clients are AP isolated the function returns NULL.
 */
struct batadv_orig_node *batadv_transtable_search(struct batadv_priv *bat_priv,
						  const u8 *src,
						  const u8 *addr,
						  unsigned short vid)
{
	struct batadv_tt_global_entry *tt_global_entry = NULL;
	struct batadv_tt_local_entry *tt_local_entry = NULL;
	struct batadv_tt_orig_list_entry *best_entry;
	struct batadv_orig_node *orig_node = NULL;

	if (src && batadv_vlan_ap_isola_get(bat_priv, vid)) {
		tt_local_entry = batadv_tt_local_hash_find(bat_priv, src, vid);
		if (!tt_local_entry ||
		    (tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING))
			goto out;
	}

	tt_global_entry = batadv_tt_global_hash_find(bat_priv, addr, vid);
	if (!tt_global_entry)
		goto out;

	/* check whether the clients should not communicate due to AP
	 * isolation
	 */
	if (tt_local_entry &&
	    _batadv_is_ap_isolated(tt_local_entry, tt_global_entry))
		goto out;

	rcu_read_lock();
	best_entry = batadv_transtable_best_orig(bat_priv, tt_global_entry);
	/* found anything? */
	if (best_entry)
		orig_node = best_entry->orig_node;
	if (orig_node && !kref_get_unless_zero(&orig_node->refcount))
		orig_node = NULL;
	rcu_read_unlock();

out:
	batadv_tt_global_entry_put(tt_global_entry);
	batadv_tt_local_entry_put(tt_local_entry);

	return orig_node;
}

/**
 * batadv_tt_global_crc() - calculates the checksum of the local table belonging
 *  to the given orig_node
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: originator for which the CRC should be computed
 * @vid: VLAN identifier for which the CRC32 has to be computed
 *
 * This function computes the checksum for the global table corresponding to a
 * specific originator. In particular, the checksum is computed as follows: For
 * each client connected to the originator the CRC32C of the MAC address and the
 * VID is computed and then all the CRC32Cs of the various clients are xor'ed
 * together.
 *
 * The idea behind is that CRC32C should be used as much as possible in order to
 * produce a unique hash of the table, but since the order which is used to feed
 * the CRC32C function affects the result and since every node in the network
 * probably sorts the clients differently, the hash function cannot be directly
 * computed over the entire table. Hence the CRC32C is used only on
 * the single client entry, while all the results are then xor'ed together
 * because the XOR operation can combine them all while trying to reduce the
 * noise as much as possible.
 *
 * Return: the checksum of the global table of a given originator.
 */
static u32 batadv_tt_global_crc(struct batadv_priv *bat_priv,
				struct batadv_orig_node *orig_node,
				unsigned short vid)
{
	struct batadv_hashtable *hash = bat_priv->tt.global_hash;
	struct batadv_tt_orig_list_entry *tt_orig;
	struct batadv_tt_common_entry *tt_common;
	struct batadv_tt_global_entry *tt_global;
	struct hlist_head *head;
	__be16 tmp_vid;
	u32 crc_tmp;
	u32 crc = 0;
	u8 flags;
	u32 i;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common, head, hash_entry) {
			tt_global = container_of(tt_common,
						 struct batadv_tt_global_entry,
						 common);
			/* compute the CRC only for entries belonging to the
			 * VLAN identified by the vid passed as parameter
			 */
			if (tt_common->vid != vid)
				continue;

			/* Roaming clients are in the global table for
			 * consistency only. They don't have to be
			 * taken into account while computing the
			 * global crc
			 */
			if (tt_common->flags & BATADV_TT_CLIENT_ROAM)
				continue;
			/* Temporary clients have not been announced yet, so
			 * they have to be skipped while computing the global
			 * crc
			 */
			if (tt_common->flags & BATADV_TT_CLIENT_TEMP)
				continue;

			/* find out if this global entry is announced by this
			 * originator
			 */
			tt_orig = batadv_tt_global_orig_entry_find(tt_global,
								   orig_node);
			if (!tt_orig)
				continue;

			/* use network order to read the VID: this ensures that
			 * every node reads the bytes in the same order.
			 */
			tmp_vid = htons(tt_common->vid);
			crc_tmp = crc32c(0, &tmp_vid, sizeof(tmp_vid));

			/* compute the CRC on flags that have to be kept in sync
			 * among nodes
			 */
			flags = tt_orig->flags;
			crc_tmp = crc32c(crc_tmp, &flags, sizeof(flags));

			crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);

			batadv_tt_orig_list_entry_put(tt_orig);
		}
		rcu_read_unlock();
	}

	return crc;
}

/**
 * batadv_tt_local_crc() - calculates the checksum of the local table
 * @bat_priv: the bat priv with all the mesh interface information
 * @vid: VLAN identifier for which the CRC32 has to be computed
 *
 * For details about the computation, please refer to the documentation for
 * batadv_tt_global_crc().
 *
 * Return: the checksum of the local table
 */
static u32 batadv_tt_local_crc(struct batadv_priv *bat_priv,
			       unsigned short vid)
{
	struct batadv_hashtable *hash = bat_priv->tt.local_hash;
	struct batadv_tt_common_entry *tt_common;
	struct hlist_head *head;
	__be16 tmp_vid;
	u32 crc_tmp;
	u32 crc = 0;
	u8 flags;
	u32 i;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common, head, hash_entry) {
			/* compute the CRC only for entries belonging to the
			 * VLAN identified by vid
			 */
			if (tt_common->vid != vid)
				continue;

			/* not yet committed clients have not to be taken into
			 * account while computing the CRC
			 */
			if (tt_common->flags & BATADV_TT_CLIENT_NEW)
				continue;

			/* use network order to read the VID: this ensures that
			 * every node reads the bytes in the same order.
			 */
			tmp_vid = htons(tt_common->vid);
			crc_tmp = crc32c(0, &tmp_vid, sizeof(tmp_vid));

			/* compute the CRC on flags that have to be kept in sync
			 * among nodes
			 */
			flags = tt_common->flags & BATADV_TT_SYNC_MASK;
			crc_tmp = crc32c(crc_tmp, &flags, sizeof(flags));

			crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);
		}
		rcu_read_unlock();
	}

	return crc;
}

/**
 * batadv_tt_req_node_release() - free tt_req node entry
 * @ref: kref pointer of the tt req_node entry
 */
static void batadv_tt_req_node_release(struct kref *ref)
{
	struct batadv_tt_req_node *tt_req_node;

	tt_req_node = container_of(ref, struct batadv_tt_req_node, refcount);

	kmem_cache_free(batadv_tt_req_cache, tt_req_node);
}

/**
 * batadv_tt_req_node_put() - decrement the tt_req_node refcounter and
 *  possibly release it
 * @tt_req_node: tt_req_node to be free'd
 */
static void batadv_tt_req_node_put(struct batadv_tt_req_node *tt_req_node)
{
	if (!tt_req_node)
		return;

	kref_put(&tt_req_node->refcount, batadv_tt_req_node_release);
}

/**
 * batadv_tt_req_list_free() - drop all pending TT requests
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_tt_req_list_free(struct batadv_priv *bat_priv)
{
	struct batadv_tt_req_node *node;
	struct hlist_node *safe;

	spin_lock_bh(&bat_priv->tt.req_list_lock);

	hlist_for_each_entry_safe(node, safe, &bat_priv->tt.req_list, list) {
		hlist_del_init(&node->list);
		batadv_tt_req_node_put(node);
	}

	spin_unlock_bh(&bat_priv->tt.req_list_lock);
}

/**
 * batadv_tt_save_orig_buffer() - cache the latest TT TVLV payload of an
 *  originator
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: originator for which the buffer should be created
 * @tt_buff: pointer to the TT TVLV payload to cache
 * @tt_buff_len: length of @tt_buff in bytes
 *
 * Replace the previously cached TT payload of @orig_node with a copy of
 * @tt_buff. The buffer is left untouched when @tt_buff_len is 0 so that
 * empty OGM updates do not discard the previously cached data.
 */
static void batadv_tt_save_orig_buffer(struct batadv_priv *bat_priv,
				       struct batadv_orig_node *orig_node,
				       const void *tt_buff,
				       u16 tt_buff_len)
{
	/* Replace the old buffer only if I received something in the
	 * last OGM (the OGM could carry no changes)
	 */
	spin_lock_bh(&orig_node->tt_buff_lock);
	if (tt_buff_len > 0) {
		kfree(orig_node->tt_buff);
		orig_node->tt_buff_len = 0;
		orig_node->tt_buff = kmalloc(tt_buff_len, GFP_ATOMIC);
		if (orig_node->tt_buff) {
			memcpy(orig_node->tt_buff, tt_buff, tt_buff_len);
			orig_node->tt_buff_len = tt_buff_len;
		}
	}
	spin_unlock_bh(&orig_node->tt_buff_lock);
}

/**
 * batadv_tt_req_purge() - drop timed-out TT requests
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_tt_req_purge(struct batadv_priv *bat_priv)
{
	struct batadv_tt_req_node *node;
	struct hlist_node *safe;

	spin_lock_bh(&bat_priv->tt.req_list_lock);
	hlist_for_each_entry_safe(node, safe, &bat_priv->tt.req_list, list) {
		if (batadv_has_timed_out(node->issued_at,
					 BATADV_TT_REQUEST_TIMEOUT)) {
			hlist_del_init(&node->list);
			batadv_tt_req_node_put(node);
		}
	}
	spin_unlock_bh(&bat_priv->tt.req_list_lock);
}

/**
 * batadv_tt_req_node_new() - search and possibly create a tt_req_node object
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: orig node this request is being issued for
 *
 * Return: the pointer to the new tt_req_node struct if no request
 * has already been issued for this orig_node, NULL otherwise.
 */
static struct batadv_tt_req_node *
batadv_tt_req_node_new(struct batadv_priv *bat_priv,
		       struct batadv_orig_node *orig_node)
{
	struct batadv_tt_req_node *tt_req_node = NULL;
	struct batadv_tt_req_node *tt_req_node_tmp;

	spin_lock_bh(&bat_priv->tt.req_list_lock);
	hlist_for_each_entry(tt_req_node_tmp, &bat_priv->tt.req_list, list) {
		if (batadv_compare_eth(tt_req_node_tmp, orig_node) &&
		    !batadv_has_timed_out(tt_req_node_tmp->issued_at,
					  BATADV_TT_REQUEST_TIMEOUT))
			goto unlock;
	}

	tt_req_node = kmem_cache_alloc(batadv_tt_req_cache, GFP_ATOMIC);
	if (!tt_req_node)
		goto unlock;

	kref_init(&tt_req_node->refcount);
	ether_addr_copy(tt_req_node->addr, orig_node->orig);
	tt_req_node->issued_at = jiffies;

	kref_get(&tt_req_node->refcount);
	hlist_add_head(&tt_req_node->list, &bat_priv->tt.req_list);
unlock:
	spin_unlock_bh(&bat_priv->tt.req_list_lock);
	return tt_req_node;
}

/**
 * batadv_tt_local_valid() - verify local tt entry and get flags
 * @entry_ptr: to be checked local tt entry
 * @data_ptr: not used but definition required to satisfy the callback prototype
 * @flags: a pointer to store TT flags for this client to
 *
 * Checks the validity of the given local TT entry. If it is, then the provided
 * flags pointer is updated.
 *
 * Return: true if the entry is a valid, false otherwise.
 */
static bool batadv_tt_local_valid(const void *entry_ptr,
				  const void *data_ptr,
				  u8 *flags)
{
	const struct batadv_tt_common_entry *tt_common_entry = entry_ptr;

	if (tt_common_entry->flags & BATADV_TT_CLIENT_NEW)
		return false;

	if (flags)
		*flags = tt_common_entry->flags;

	return true;
}

/**
 * batadv_tt_global_valid() - verify global tt entry and get flags
 * @entry_ptr: to be checked global tt entry
 * @data_ptr: an orig_node object (may be NULL)
 * @flags: a pointer to store TT flags for this client to
 *
 * Checks the validity of the given global TT entry. If it is, then the provided
 * flags pointer is updated either with the common (summed) TT flags if data_ptr
 * is NULL or the specific, per originator TT flags otherwise.
 *
 * Return: true if the entry is a valid, false otherwise.
 */
static bool batadv_tt_global_valid(const void *entry_ptr,
				   const void *data_ptr,
				   u8 *flags)
{
	const struct batadv_tt_common_entry *tt_common_entry = entry_ptr;
	const struct batadv_tt_global_entry *tt_global_entry;
	const struct batadv_orig_node *orig_node = data_ptr;

	if (tt_common_entry->flags & BATADV_TT_CLIENT_ROAM ||
	    tt_common_entry->flags & BATADV_TT_CLIENT_TEMP)
		return false;

	tt_global_entry = container_of(tt_common_entry,
				       struct batadv_tt_global_entry,
				       common);

	return batadv_tt_global_entry_has_orig(tt_global_entry, orig_node,
					       flags);
}

/**
 * batadv_tt_tvlv_generate() - fill the tvlv buff with the tt entries from the
 *  specified tt hash
 * @bat_priv: the bat priv with all the mesh interface information
 * @hash: hash table containing the tt entries
 * @tt_len: expected tvlv tt data buffer length in number of bytes
 * @tvlv_buff: pointer to the buffer to fill with the TT data
 * @valid_cb: function to filter tt change entries and to return TT flags
 * @cb_data: data passed to the filter function as argument
 *
 * Fills the tvlv buff with the tt entries from the specified hash. If valid_cb
 * is not provided then this becomes a no-op.
 *
 * Return: Remaining unused length in tvlv_buff.
 */
static u16 batadv_tt_tvlv_generate(struct batadv_priv *bat_priv,
				   struct batadv_hashtable *hash,
				   void *tvlv_buff, u16 tt_len,
				   bool (*valid_cb)(const void *,
						    const void *,
						    u8 *flags),
				   void *cb_data)
{
	struct batadv_tt_common_entry *tt_common_entry;
	struct batadv_tvlv_tt_change *tt_change;
	struct hlist_head *head;
	u16 tt_num_entries = 0;
	u16 tt_tot;
	u8 flags;
	bool ret;
	u32 i;

	tt_tot = batadv_tt_entries(tt_len);
	tt_change = tvlv_buff;

	if (!valid_cb)
		return tt_len;

	rcu_read_lock();
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		hlist_for_each_entry_rcu(tt_common_entry,
					 head, hash_entry) {
			if (tt_tot == tt_num_entries)
				break;

			ret = valid_cb(tt_common_entry, cb_data, &flags);
			if (!ret)
				continue;

			ether_addr_copy(tt_change->addr, tt_common_entry->addr);
			tt_change->flags = flags;
			tt_change->vid = htons(tt_common_entry->vid);
			memset(tt_change->reserved, 0,
			       sizeof(tt_change->reserved));

			tt_num_entries++;
			tt_change++;
		}
	}
	rcu_read_unlock();

	return batadv_tt_len(tt_tot - tt_num_entries);
}

/**
 * batadv_tt_global_check_crc() - check if all the CRCs are correct
 * @orig_node: originator for which the CRCs have to be checked
 * @tt_vlan: pointer to the first tvlv VLAN entry
 * @num_vlan: number of tvlv VLAN entries
 *
 * Return: true if all the received CRCs match the locally stored ones, false
 * otherwise
 */
static bool batadv_tt_global_check_crc(struct batadv_orig_node *orig_node,
				       struct batadv_tvlv_tt_vlan_data *tt_vlan,
				       u16 num_vlan)
{
	struct batadv_tvlv_tt_vlan_data *tt_vlan_tmp;
	struct batadv_orig_node_vlan *vlan;
	int orig_num_vlan;
	u32 crc;
	int i;

	/* check if each received CRC matches the locally stored one */
	for (i = 0; i < num_vlan; i++) {
		tt_vlan_tmp = tt_vlan + i;

		/* if orig_node is a backbone node for this VLAN, don't check
		 * the CRC as we ignore all the global entries over it
		 */
		if (batadv_bla_is_backbone_gw_orig(orig_node->bat_priv,
						   orig_node->orig,
						   ntohs(tt_vlan_tmp->vid)))
			continue;

		vlan = batadv_orig_node_vlan_get(orig_node,
						 ntohs(tt_vlan_tmp->vid));
		if (!vlan)
			return false;

		crc = vlan->tt.crc;
		batadv_orig_node_vlan_put(vlan);

		if (crc != ntohl(tt_vlan_tmp->crc))
			return false;
	}

	/* check if any excess VLANs exist locally for the originator
	 * which are not mentioned in the TVLV from the originator.
	 */
	rcu_read_lock();
	orig_num_vlan = 0;
	hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list)
		orig_num_vlan++;
	rcu_read_unlock();

	if (orig_num_vlan > num_vlan)
		return false;

	return true;
}

/**
 * batadv_tt_local_update_crc() - update all the local CRCs
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_tt_local_update_crc(struct batadv_priv *bat_priv)
{
	struct batadv_meshif_vlan *vlan;

	/* recompute the global CRC for each VLAN */
	rcu_read_lock();
	hlist_for_each_entry_rcu(vlan, &bat_priv->meshif_vlan_list, list) {
		vlan->tt.crc = batadv_tt_local_crc(bat_priv, vlan->vid);
	}
	rcu_read_unlock();
}

/**
 * batadv_tt_global_update_crc() - update all the global CRCs for this orig_node
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: the orig_node for which the CRCs have to be updated
 */
static void batadv_tt_global_update_crc(struct batadv_priv *bat_priv,
					struct batadv_orig_node *orig_node)
{
	struct batadv_orig_node_vlan *vlan;
	u32 crc;

	/* recompute the global CRC for each VLAN */
	rcu_read_lock();
	hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
		/* if orig_node is a backbone node for this VLAN, don't compute
		 * the CRC as we ignore all the global entries over it
		 */
		if (batadv_bla_is_backbone_gw_orig(bat_priv, orig_node->orig,
						   vlan->vid))
			continue;

		crc = batadv_tt_global_crc(bat_priv, orig_node, vlan->vid);
		vlan->tt.crc = crc;
	}
	rcu_read_unlock();
}

/**
 * batadv_send_tt_request() - send a TT Request message to a given node
 * @bat_priv: the bat priv with all the mesh interface information
 * @dst_orig_node: the destination of the message
 * @ttvn: the version number that the source of the message is looking for
 * @tt_vlan: pointer to the first tvlv VLAN object to request
 * @num_vlan: number of tvlv VLAN entries
 * @full_table: ask for the entire translation table if true, while only for the
 *  last TT diff otherwise
 *
 * Return: true if the TT Request was sent, false otherwise
 */
static bool batadv_send_tt_request(struct batadv_priv *bat_priv,
				   struct batadv_orig_node *dst_orig_node,
				   u8 ttvn,
				   struct batadv_tvlv_tt_vlan_data *tt_vlan,
				   u16 num_vlan, bool full_table)
{
	struct batadv_tvlv_tt_data *tvlv_tt_data = NULL;
	struct batadv_tt_req_node *tt_req_node = NULL;
	struct batadv_hard_iface *primary_if;
	bool ret = false;
	int size;
	int i;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	/* The new tt_req will be issued only if I'm not waiting for a
	 * reply from the same orig_node yet
	 */
	tt_req_node = batadv_tt_req_node_new(bat_priv, dst_orig_node);
	if (!tt_req_node)
		goto out;

	size = struct_size(tvlv_tt_data, vlan_data, num_vlan);
	tvlv_tt_data = kzalloc(size, GFP_ATOMIC);
	if (!tvlv_tt_data)
		goto out;

	tvlv_tt_data->flags = BATADV_TT_REQUEST;
	tvlv_tt_data->ttvn = ttvn;
	tvlv_tt_data->num_vlan = htons(num_vlan);

	/* send all the CRCs within the request. This is needed by intermediate
	 * nodes to ensure they have the correct table before replying
	 */
	for (i = 0; i < num_vlan; i++) {
		tvlv_tt_data->vlan_data[i].vid = tt_vlan->vid;
		tvlv_tt_data->vlan_data[i].crc = tt_vlan->crc;

		tt_vlan++;
	}

	if (full_table)
		tvlv_tt_data->flags |= BATADV_TT_FULL_TABLE;

	batadv_dbg(BATADV_DBG_TT, bat_priv, "Sending TT_REQUEST to %pM [%c]\n",
		   dst_orig_node->orig, full_table ? 'F' : '.');

	batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_TX);
	batadv_tvlv_unicast_send(bat_priv, primary_if->net_dev->dev_addr,
				 dst_orig_node->orig, BATADV_TVLV_TT, 1,
				 tvlv_tt_data, size);
	ret = true;

out:
	batadv_hardif_put(primary_if);

	if (!ret && tt_req_node) {
		spin_lock_bh(&bat_priv->tt.req_list_lock);
		if (!hlist_unhashed(&tt_req_node->list)) {
			hlist_del_init(&tt_req_node->list);
			batadv_tt_req_node_put(tt_req_node);
		}
		spin_unlock_bh(&bat_priv->tt.req_list_lock);
	}

	batadv_tt_req_node_put(tt_req_node);

	kfree(tvlv_tt_data);
	return ret;
}

/**
 * batadv_send_other_tt_response() - send reply to tt request concerning another
 *  node's translation table
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_data: tt data containing the tt request information
 * @req_src: mac address of tt request sender
 * @req_dst: mac address of tt request recipient
 *
 * Return: true if tt request reply was sent, false otherwise.
 */
static bool batadv_send_other_tt_response(struct batadv_priv *bat_priv,
					  struct batadv_tvlv_tt_data *tt_data,
					  u8 *req_src, u8 *req_dst)
{
	struct batadv_orig_node *res_dst_orig_node = NULL;
	struct batadv_tvlv_tt_data *tvlv_tt_data = NULL;
	struct batadv_orig_node *req_dst_orig_node;
	struct batadv_tvlv_tt_change *tt_change;
	bool ret = false;
	bool full_table;
	u8 orig_ttvn;
	u16 tvlv_len;
	u8 req_ttvn;
	s32 tt_len;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Received TT_REQUEST from %pM for ttvn: %u (%pM) [%c]\n",
		   req_src, tt_data->ttvn, req_dst,
		   ((tt_data->flags & BATADV_TT_FULL_TABLE) ? 'F' : '.'));

	/* Let's get the orig node of the REAL destination */
	req_dst_orig_node = batadv_orig_hash_find(bat_priv, req_dst);
	if (!req_dst_orig_node)
		goto out;

	res_dst_orig_node = batadv_orig_hash_find(bat_priv, req_src);
	if (!res_dst_orig_node)
		goto out;

	orig_ttvn = READ_ONCE(req_dst_orig_node->last_ttvn);
	req_ttvn = tt_data->ttvn;

	/* this node doesn't have the requested data */
	if (orig_ttvn != req_ttvn ||
	    !batadv_tt_global_check_crc(req_dst_orig_node, tt_data->vlan_data,
					ntohs(tt_data->num_vlan)))
		goto out;

	/* If the full table has been explicitly requested */
	if (tt_data->flags & BATADV_TT_FULL_TABLE ||
	    !req_dst_orig_node->tt_buff)
		full_table = true;
	else
		full_table = false;

	/* TT fragmentation hasn't been implemented yet, so send as many
	 * TT entries fit a single packet as possible only
	 */
	if (!full_table) {
		spin_lock_bh(&req_dst_orig_node->tt_buff_lock);
		tt_len = req_dst_orig_node->tt_buff_len;

		tvlv_len = batadv_tt_prepare_tvlv_global_data(req_dst_orig_node,
							      &tvlv_tt_data,
							      &tt_change,
							      &tt_len);
		if (!tt_len)
			goto unlock;

		/* Copy the last orig_node's OGM buffer */
		memcpy(tt_change, req_dst_orig_node->tt_buff,
		       req_dst_orig_node->tt_buff_len);
		spin_unlock_bh(&req_dst_orig_node->tt_buff_lock);
	} else {
		/* allocate the tvlv, put the tt_data and all the tt_vlan_data
		 * in the initial part
		 */
		tt_len = -1;
		tvlv_len = batadv_tt_prepare_tvlv_global_data(req_dst_orig_node,
							      &tvlv_tt_data,
							      &tt_change,
							      &tt_len);
		if (!tt_len)
			goto out;

		/* fill the rest of the tvlv with the real TT entries */
		tvlv_len -= batadv_tt_tvlv_generate(bat_priv,
						    bat_priv->tt.global_hash,
						    tt_change, tt_len,
						    batadv_tt_global_valid,
						    req_dst_orig_node);
	}

	/* Don't send the response, if larger than fragmented packet. */
	tt_len = sizeof(struct batadv_unicast_tvlv_packet) + tvlv_len;
	if (tt_len > READ_ONCE(bat_priv->packet_size_max)) {
		net_ratelimited_function(batadv_info, bat_priv->mesh_iface,
					 "Ignoring TT_REQUEST from %pM; Response size exceeds max packet size.\n",
					 res_dst_orig_node->orig);
		goto out;
	}

	tvlv_tt_data->flags = BATADV_TT_RESPONSE;
	tvlv_tt_data->ttvn = req_ttvn;

	if (full_table)
		tvlv_tt_data->flags |= BATADV_TT_FULL_TABLE;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Sending TT_RESPONSE %pM for %pM [%c] (ttvn: %u)\n",
		   res_dst_orig_node->orig, req_dst_orig_node->orig,
		   full_table ? 'F' : '.', req_ttvn);

	batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_TX);

	batadv_tvlv_unicast_send(bat_priv, req_dst_orig_node->orig,
				 req_src, BATADV_TVLV_TT, 1, tvlv_tt_data,
				 tvlv_len);

	ret = true;
	goto out;

unlock:
	spin_unlock_bh(&req_dst_orig_node->tt_buff_lock);

out:
	batadv_orig_node_put(res_dst_orig_node);
	batadv_orig_node_put(req_dst_orig_node);
	kfree(tvlv_tt_data);
	return ret;
}

/**
 * batadv_send_my_tt_response() - send reply to tt request concerning this
 *  node's translation table
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_data: tt data containing the tt request information
 * @req_src: mac address of tt request sender
 *
 * Return: true if tt request reply was sent, false otherwise.
 */
static bool batadv_send_my_tt_response(struct batadv_priv *bat_priv,
				       struct batadv_tvlv_tt_data *tt_data,
				       u8 *req_src)
{
	struct batadv_tvlv_tt_data *tvlv_tt_data = NULL;
	struct batadv_hard_iface *primary_if = NULL;
	struct batadv_tvlv_tt_change *tt_change;
	struct batadv_orig_node *orig_node;
	bool full_table;
	u16 tvlv_len;
	u8 req_ttvn;
	u8 my_ttvn;
	s32 tt_len;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Received TT_REQUEST from %pM for ttvn: %u (me) [%c]\n",
		   req_src, tt_data->ttvn,
		   ((tt_data->flags & BATADV_TT_FULL_TABLE) ? 'F' : '.'));

	spin_lock_bh(&bat_priv->tt.commit_lock);

	my_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
	req_ttvn = tt_data->ttvn;

	orig_node = batadv_orig_hash_find(bat_priv, req_src);
	if (!orig_node)
		goto out;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	/* If the full table has been explicitly requested or the gap
	 * is too big send the whole local translation table
	 */
	if (tt_data->flags & BATADV_TT_FULL_TABLE || my_ttvn != req_ttvn ||
	    !bat_priv->tt.last_changeset)
		full_table = true;
	else
		full_table = false;

	/* TT fragmentation hasn't been implemented yet, so send as many
	 * TT entries fit a single packet as possible only
	 */
	if (!full_table) {
		spin_lock_bh(&bat_priv->tt.last_changeset_lock);

		tt_len = bat_priv->tt.last_changeset_len;
		tvlv_len = batadv_tt_prepare_tvlv_local_data(bat_priv,
							     &tvlv_tt_data,
							     &tt_change,
							     &tt_len);
		if (!tt_len || !tvlv_len)
			goto unlock;

		/* Copy the last orig_node's OGM buffer */
		memcpy(tt_change, bat_priv->tt.last_changeset,
		       bat_priv->tt.last_changeset_len);
		spin_unlock_bh(&bat_priv->tt.last_changeset_lock);
	} else {
		req_ttvn = (u8)atomic_read(&bat_priv->tt.vn);

		/* allocate the tvlv, put the tt_data and all the tt_vlan_data
		 * in the initial part
		 */
		tt_len = -1;
		tvlv_len = batadv_tt_prepare_tvlv_local_data(bat_priv,
							     &tvlv_tt_data,
							     &tt_change,
							     &tt_len);
		if (!tt_len || !tvlv_len)
			goto out;

		/* fill the rest of the tvlv with the real TT entries */
		tvlv_len -= batadv_tt_tvlv_generate(bat_priv,
						    bat_priv->tt.local_hash,
						    tt_change, tt_len,
						    batadv_tt_local_valid,
						    NULL);
	}

	tvlv_tt_data->flags = BATADV_TT_RESPONSE;
	tvlv_tt_data->ttvn = req_ttvn;

	if (full_table)
		tvlv_tt_data->flags |= BATADV_TT_FULL_TABLE;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Sending TT_RESPONSE to %pM [%c] (ttvn: %u)\n",
		   orig_node->orig, full_table ? 'F' : '.', req_ttvn);

	batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_TX);

	batadv_tvlv_unicast_send(bat_priv, primary_if->net_dev->dev_addr,
				 req_src, BATADV_TVLV_TT, 1, tvlv_tt_data,
				 tvlv_len);

	goto out;

unlock:
	spin_unlock_bh(&bat_priv->tt.last_changeset_lock);
out:
	spin_unlock_bh(&bat_priv->tt.commit_lock);
	batadv_orig_node_put(orig_node);
	batadv_hardif_put(primary_if);
	kfree(tvlv_tt_data);
	/* The packet was for this host, so it doesn't need to be re-routed */
	return true;
}

/**
 * batadv_send_tt_response() - send reply to tt request
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_data: tt data containing the tt request information
 * @req_src: mac address of tt request sender
 * @req_dst: mac address of tt request recipient
 *
 * Return: true if tt request reply was sent, false otherwise.
 */
static bool batadv_send_tt_response(struct batadv_priv *bat_priv,
				    struct batadv_tvlv_tt_data *tt_data,
				    u8 *req_src, u8 *req_dst)
{
	if (batadv_is_my_mac(bat_priv, req_dst))
		return batadv_send_my_tt_response(bat_priv, tt_data, req_src);
	return batadv_send_other_tt_response(bat_priv, tt_data, req_src,
					     req_dst);
}

/**
 * _batadv_tt_update_changes() - apply a list of TT changes to the global TT
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: originator announcing the changes
 * @tt_change: array of TT change entries to apply
 * @tt_num_changes: number of entries in @tt_change
 * @ttvn: TTVN of @orig_node corresponding to @tt_change
 *
 * Walk @tt_change and add/remove the announced clients in the global TT.
 * Abort early without marking the @orig_node TT as initialized if adding
 * an entry fails, so that the next TT request can re-sync the full table.
 */
static void _batadv_tt_update_changes(struct batadv_priv *bat_priv,
				      struct batadv_orig_node *orig_node,
				      struct batadv_tvlv_tt_change *tt_change,
				      u16 tt_num_changes, u8 ttvn)
{
	int roams;
	int i;

	for (i = 0; i < tt_num_changes; i++) {
		if ((tt_change + i)->flags & BATADV_TT_CLIENT_DEL) {
			roams = (tt_change + i)->flags & BATADV_TT_CLIENT_ROAM;
			batadv_tt_global_del(bat_priv, orig_node,
					     (tt_change + i)->addr,
					     ntohs((tt_change + i)->vid),
					     "tt removed by changes",
					     roams);
		} else {
			if (!batadv_tt_global_add(bat_priv, orig_node,
						  (tt_change + i)->addr,
						  ntohs((tt_change + i)->vid),
						  (tt_change + i)->flags, ttvn))
				/* In case of problem while storing a
				 * global_entry, we stop the updating
				 * procedure without committing the
				 * ttvn change. This will avoid to send
				 * corrupted data on tt_request
				 */
				return;
		}
	}
	set_bit(BATADV_ORIG_CAPA_HAS_TT, &orig_node->capa_initialized);
}

/**
 * batadv_tt_fill_gtable() - replace the cached TT of an originator with a
 *  full table response
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_change: array of TT change entries describing the full table
 * @ttvn: TTVN announced together with the full table
 * @resp_src: MAC address of the responder
 * @num_entries: number of entries in @tt_change
 *
 * Drop the previously known global TT entries of @resp_src and replace them
 * with the entries from a freshly received full TT response.
 */
static void batadv_tt_fill_gtable(struct batadv_priv *bat_priv,
				  struct batadv_tvlv_tt_change *tt_change,
				  u8 ttvn, u8 *resp_src,
				  u16 num_entries)
{
	struct batadv_orig_node *orig_node;

	orig_node = batadv_orig_hash_find(bat_priv, resp_src);
	if (!orig_node)
		goto out;

	/* Purge the old table first.. */
	batadv_tt_global_del_orig(bat_priv, orig_node, -1,
				  "Received full table");

	_batadv_tt_update_changes(bat_priv, orig_node, tt_change, num_entries,
				  ttvn);

	spin_lock_bh(&orig_node->tt_buff_lock);
	kfree(orig_node->tt_buff);
	orig_node->tt_buff_len = 0;
	orig_node->tt_buff = NULL;
	spin_unlock_bh(&orig_node->tt_buff_lock);

	WRITE_ONCE(orig_node->last_ttvn, ttvn);

out:
	batadv_orig_node_put(orig_node);
}

/**
 * batadv_tt_update_changes() - apply an incremental TT changeset to the
 *  global TT
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: originator announcing the changes
 * @tt_num_changes: number of entries in @tt_change
 * @ttvn: TTVN of @orig_node corresponding to @tt_change
 * @tt_change: array of TT change entries to apply
 */
static void batadv_tt_update_changes(struct batadv_priv *bat_priv,
				     struct batadv_orig_node *orig_node,
				     u16 tt_num_changes, u8 ttvn,
				     struct batadv_tvlv_tt_change *tt_change)
{
	_batadv_tt_update_changes(bat_priv, orig_node, tt_change,
				  tt_num_changes, ttvn);

	batadv_tt_save_orig_buffer(bat_priv, orig_node, tt_change,
				   batadv_tt_len(tt_num_changes));
	WRITE_ONCE(orig_node->last_ttvn, ttvn);
}

/**
 * batadv_is_my_client() - check if a client is served by the local node
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the client to check
 * @vid: VLAN identifier
 *
 * Return: true if the client is served by this node, false otherwise.
 */
bool batadv_is_my_client(struct batadv_priv *bat_priv, const u8 *addr,
			 unsigned short vid)
{
	struct batadv_tt_local_entry *tt_local_entry;
	bool ret = false;

	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid);
	if (!tt_local_entry)
		goto out;
	/* Check if the client has been logically deleted (but is kept for
	 * consistency purpose)
	 */
	if ((tt_local_entry->common.flags & BATADV_TT_CLIENT_PENDING) ||
	    (tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM))
		goto out;
	ret = true;
out:
	batadv_tt_local_entry_put(tt_local_entry);
	return ret;
}

/**
 * batadv_handle_tt_response() - process incoming tt reply
 * @bat_priv: the bat priv with all the mesh interface information
 * @tt_data: tt data containing the tt request information
 * @resp_src: mac address of tt reply sender
 * @num_entries: number of tt change entries appended to the tt data
 */
static void batadv_handle_tt_response(struct batadv_priv *bat_priv,
				      struct batadv_tvlv_tt_data *tt_data,
				      u8 *resp_src, u16 num_entries)
{
	struct batadv_orig_node *orig_node = NULL;
	struct batadv_tvlv_tt_change *tt_change;
	struct batadv_tt_req_node *node;
	u8 *tvlv_ptr = (u8 *)tt_data;
	struct hlist_node *safe;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Received TT_RESPONSE from %pM for ttvn %d t_size: %d [%c]\n",
		   resp_src, tt_data->ttvn, num_entries,
		   ((tt_data->flags & BATADV_TT_FULL_TABLE) ? 'F' : '.'));

	orig_node = batadv_orig_hash_find(bat_priv, resp_src);
	if (!orig_node)
		goto out;

	spin_lock_bh(&orig_node->tt_lock);

	tvlv_ptr += struct_size(tt_data, vlan_data, ntohs(tt_data->num_vlan));

	tt_change = (struct batadv_tvlv_tt_change *)tvlv_ptr;
	if (tt_data->flags & BATADV_TT_FULL_TABLE) {
		batadv_tt_fill_gtable(bat_priv, tt_change, tt_data->ttvn,
				      resp_src, num_entries);
	} else {
		batadv_tt_update_changes(bat_priv, orig_node, num_entries,
					 tt_data->ttvn, tt_change);
	}

	/* Recalculate the CRC for this orig_node and store it */
	batadv_tt_global_update_crc(bat_priv, orig_node);

	spin_unlock_bh(&orig_node->tt_lock);

	/* Delete the tt_req_node from pending tt_requests list */
	spin_lock_bh(&bat_priv->tt.req_list_lock);
	hlist_for_each_entry_safe(node, safe, &bat_priv->tt.req_list, list) {
		if (!batadv_compare_eth(node->addr, resp_src))
			continue;
		hlist_del_init(&node->list);
		batadv_tt_req_node_put(node);
	}

	spin_unlock_bh(&bat_priv->tt.req_list_lock);
out:
	batadv_orig_node_put(orig_node);
}

/**
 * batadv_tt_roam_list_free() - drop all entries from the roaming clients list
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_tt_roam_list_free(struct batadv_priv *bat_priv)
{
	struct batadv_tt_roam_node *node;
	struct batadv_tt_roam_node *safe;

	spin_lock_bh(&bat_priv->tt.roam_list_lock);

	list_for_each_entry_safe(node, safe, &bat_priv->tt.roam_list, list) {
		list_del(&node->list);
		kmem_cache_free(batadv_tt_roam_cache, node);
	}

	spin_unlock_bh(&bat_priv->tt.roam_list_lock);
}

/**
 * batadv_tt_roam_purge() - drop timed-out roaming clients
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_tt_roam_purge(struct batadv_priv *bat_priv)
{
	struct batadv_tt_roam_node *node;
	struct batadv_tt_roam_node *safe;

	spin_lock_bh(&bat_priv->tt.roam_list_lock);
	list_for_each_entry_safe(node, safe, &bat_priv->tt.roam_list, list) {
		if (!batadv_has_timed_out(node->first_time,
					  BATADV_ROAMING_MAX_TIME))
			continue;

		list_del(&node->list);
		kmem_cache_free(batadv_tt_roam_cache, node);
	}
	spin_unlock_bh(&bat_priv->tt.roam_list_lock);
}

/**
 * batadv_tt_check_roam_count() - check if a client has roamed too frequently
 * @bat_priv: the bat priv with all the mesh interface information
 * @client: mac address of the roaming client
 * @vid: VLAN identifier
 *
 * This function checks whether the client already reached the
 * maximum number of possible roaming phases. In this case the ROAMING_ADV
 * will not be sent.
 *
 * Return: true if the ROAMING_ADV can be sent, false otherwise
 */
static bool batadv_tt_check_roam_count(struct batadv_priv *bat_priv, u8 *client, u16 vid)
{
	struct batadv_tt_roam_node *tt_roam_node;
	bool ret = false;

	spin_lock_bh(&bat_priv->tt.roam_list_lock);
	/* The new tt_req will be issued only if I'm not waiting for a
	 * reply from the same orig_node yet
	 */
	list_for_each_entry(tt_roam_node, &bat_priv->tt.roam_list, list) {
		if (!batadv_compare_eth(tt_roam_node->addr, client))
			continue;

		if (tt_roam_node->vid != vid)
			continue;

		if (batadv_has_timed_out(tt_roam_node->first_time,
					 BATADV_ROAMING_MAX_TIME))
			continue;

		if (!batadv_atomic_dec_not_zero(&tt_roam_node->counter))
			/* Sorry, you roamed too many times! */
			goto unlock;
		ret = true;
		break;
	}

	if (!ret) {
		tt_roam_node = kmem_cache_alloc(batadv_tt_roam_cache,
						GFP_ATOMIC);
		if (!tt_roam_node)
			goto unlock;

		tt_roam_node->first_time = jiffies;
		atomic_set(&tt_roam_node->counter,
			   BATADV_ROAMING_MAX_COUNT - 1);
		ether_addr_copy(tt_roam_node->addr, client);
		tt_roam_node->vid = vid;

		list_add(&tt_roam_node->list, &bat_priv->tt.roam_list);
		ret = true;
	}

unlock:
	spin_unlock_bh(&bat_priv->tt.roam_list_lock);
	return ret;
}

/**
 * batadv_send_roam_adv() - send a roaming advertisement message
 * @bat_priv: the bat priv with all the mesh interface information
 * @client: mac address of the roaming client
 * @vid: VLAN identifier
 * @orig_node: message destination
 *
 * Send a ROAMING_ADV message to the node which was previously serving this
 * client. This is done to inform the node that from now on all traffic destined
 * for this particular roamed client has to be forwarded to the sender of the
 * roaming message.
 */
static void batadv_send_roam_adv(struct batadv_priv *bat_priv, u8 *client,
				 unsigned short vid,
				 struct batadv_orig_node *orig_node)
{
	struct batadv_tvlv_roam_adv tvlv_roam;
	struct batadv_hard_iface *primary_if;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	/* before going on we have to check whether the client has
	 * already roamed to us too many times
	 */
	if (!batadv_tt_check_roam_count(bat_priv, client, vid))
		goto out;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Sending ROAMING_ADV to %pM (client %pM, vid: %d)\n",
		   orig_node->orig, client, batadv_print_vid(vid));

	batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_TX);

	memcpy(tvlv_roam.client, client, sizeof(tvlv_roam.client));
	tvlv_roam.vid = htons(vid);

	batadv_tvlv_unicast_send(bat_priv, primary_if->net_dev->dev_addr,
				 orig_node->orig, BATADV_TVLV_ROAM, 1,
				 &tvlv_roam, sizeof(tvlv_roam));

out:
	batadv_hardif_put(primary_if);
}

/**
 * batadv_tt_purge() - periodic worker to maintain the translation table
 * @work: delayed work embedded in the per-mesh-interface TT state
 *
 * Purge timed-out entries from the local and global TT, drop stale TT
 * requests and roaming clients, and reschedule the next run after
 * BATADV_TT_WORK_PERIOD milliseconds.
 */
static void batadv_tt_purge(struct work_struct *work)
{
	struct delayed_work *delayed_work;
	struct batadv_priv_tt *priv_tt;
	struct batadv_priv *bat_priv;

	delayed_work = to_delayed_work(work);
	priv_tt = container_of(delayed_work, struct batadv_priv_tt, work);
	bat_priv = container_of(priv_tt, struct batadv_priv, tt);

	batadv_tt_local_purge(bat_priv, BATADV_TT_LOCAL_TIMEOUT);
	batadv_tt_global_purge(bat_priv);
	batadv_tt_req_purge(bat_priv);
	batadv_tt_roam_purge(bat_priv);

	queue_delayed_work(batadv_event_workqueue, &bat_priv->tt.work,
			   msecs_to_jiffies(BATADV_TT_WORK_PERIOD));
}

/**
 * batadv_tt_free() - Free translation table of mesh interface
 * @bat_priv: the bat priv with all the mesh interface information
 */
void batadv_tt_free(struct batadv_priv *bat_priv)
{
	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_ROAM, 1);

	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_TT, 1);
	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_TT, 1);

	disable_delayed_work_sync(&bat_priv->tt.work);

	batadv_tt_local_table_free(bat_priv);
	batadv_tt_global_table_free(bat_priv);
	batadv_tt_req_list_free(bat_priv);
	batadv_tt_changes_list_free(bat_priv);
	batadv_tt_roam_list_free(bat_priv);

	kfree(bat_priv->tt.last_changeset);
}

/**
 * batadv_tt_local_set_flags() - set or unset the specified flags on the local
 *  table and possibly count them in the TT size
 * @bat_priv: the bat priv with all the mesh interface information
 * @flags: the flag to switch
 * @enable: whether to set or unset the flag
 * @count: whether to increase the TT size by the number of changed entries
 */
static void batadv_tt_local_set_flags(struct batadv_priv *bat_priv, u16 flags,
				      bool enable, bool count)
{
	struct batadv_hashtable *hash = bat_priv->tt.local_hash;
	struct batadv_tt_common_entry *tt_common_entry;
	struct hlist_head *head;
	u32 i;

	if (!hash)
		return;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry,
					 head, hash_entry) {
			if (enable) {
				if ((tt_common_entry->flags & flags) == flags)
					continue;
				tt_common_entry->flags |= flags;
			} else {
				if (!(tt_common_entry->flags & flags))
					continue;
				tt_common_entry->flags &= ~flags;
			}

			if (!count)
				continue;

			batadv_tt_local_size_inc(bat_priv,
						 tt_common_entry->vid);
		}
		rcu_read_unlock();
	}
}

/**
 * batadv_tt_local_purge_pending_clients() - finalise removal of pending local
 *  clients
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Iterate over the local TT and physically remove every entry that has been
 * marked as BATADV_TT_CLIENT_PENDING.
 */
static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv)
{
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct batadv_hashtable *hash = bat_priv->tt.local_hash;
	struct batadv_tt_common_entry *tt_common;
	struct batadv_tt_local_entry *tt_local;
	struct hlist_node *node_tmp;
	struct hlist_head *head;
	u32 i;

	if (!hash)
		return;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		list_lock = &hash->list_locks[i];

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(tt_common, node_tmp, head,
					  hash_entry) {
			if (!(tt_common->flags & BATADV_TT_CLIENT_PENDING))
				continue;

			batadv_dbg(BATADV_DBG_TT, bat_priv,
				   "Deleting local tt entry (%pM, vid: %d): pending\n",
				   tt_common->addr,
				   batadv_print_vid(tt_common->vid));

			batadv_tt_local_size_dec(bat_priv, tt_common->vid);
			hlist_del_rcu(&tt_common->hash_entry);
			tt_local = container_of(tt_common,
						struct batadv_tt_local_entry,
						common);

			batadv_tt_local_entry_put(tt_local);
		}
		spin_unlock_bh(list_lock);
	}
}

/**
 * batadv_tt_local_commit_changes_nolock() - commit all pending local tt changes
 *  which have been queued in the time since the last commit
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Caller must hold tt->commit_lock.
 */
static void batadv_tt_local_commit_changes_nolock(struct batadv_priv *bat_priv)
{
	lockdep_assert_held(&bat_priv->tt.commit_lock);

	if (READ_ONCE(bat_priv->tt.local_changes) == 0) {
		if (!batadv_atomic_dec_not_zero(&bat_priv->tt.ogm_append_cnt))
			batadv_tt_tvlv_container_update(bat_priv);
		return;
	}

	batadv_tt_local_set_flags(bat_priv, BATADV_TT_CLIENT_NEW, false, true);

	batadv_tt_local_purge_pending_clients(bat_priv);
	batadv_tt_local_update_crc(bat_priv);

	/* Increment the TTVN only once per OGM interval */
	atomic_inc(&bat_priv->tt.vn);
	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Local changes committed, updating to ttvn %u\n",
		   (u8)atomic_read(&bat_priv->tt.vn));

	/* reset the sending counter */
	atomic_set(&bat_priv->tt.ogm_append_cnt, BATADV_TT_OGM_APPEND_MAX);
	batadv_tt_tvlv_container_update(bat_priv);
}

/**
 * batadv_tt_local_commit_changes() - commit all pending local tt changes which
 *  have been queued in the time since the last commit
 * @bat_priv: the bat priv with all the mesh interface information
 */
void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
{
	spin_lock_bh(&bat_priv->tt.commit_lock);
	batadv_tt_local_commit_changes_nolock(bat_priv);
	spin_unlock_bh(&bat_priv->tt.commit_lock);
}

/**
 * batadv_is_ap_isolated() - Check if packet from upper layer should be dropped
 * @bat_priv: the bat priv with all the mesh interface information
 * @src: source mac address of packet
 * @dst: destination mac address of packet
 * @vid: vlan id of packet
 *
 * Return: true when src+dst(+vid) pair should be isolated, false otherwise
 */
bool batadv_is_ap_isolated(struct batadv_priv *bat_priv, u8 *src, u8 *dst,
			   unsigned short vid)
{
	struct batadv_tt_global_entry *tt_global_entry;
	struct batadv_tt_local_entry *tt_local_entry;
	struct batadv_meshif_vlan *vlan;
	bool ret = false;

	vlan = batadv_meshif_vlan_get(bat_priv, vid);
	if (!vlan)
		return false;

	if (!READ_ONCE(vlan->ap_isolation))
		goto vlan_put;

	tt_local_entry = batadv_tt_local_hash_find(bat_priv, dst, vid);
	if (!tt_local_entry)
		goto vlan_put;

	tt_global_entry = batadv_tt_global_hash_find(bat_priv, src, vid);
	if (!tt_global_entry)
		goto local_entry_put;

	if (_batadv_is_ap_isolated(tt_local_entry, tt_global_entry))
		ret = true;

	batadv_tt_global_entry_put(tt_global_entry);
local_entry_put:
	batadv_tt_local_entry_put(tt_local_entry);
vlan_put:
	batadv_meshif_vlan_put(vlan);
	return ret;
}

/**
 * batadv_tt_update_orig() - update global translation table with new tt
 *  information received via ogms
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: the orig_node of the ogm
 * @tt_buff: pointer to the first tvlv VLAN entry
 * @tt_num_vlan: number of tvlv VLAN entries
 * @tt_change: pointer to the first entry in the TT buffer
 * @tt_num_changes: number of tt changes inside the tt buffer
 * @ttvn: translation table version number of this changeset
 */
static void batadv_tt_update_orig(struct batadv_priv *bat_priv,
				  struct batadv_orig_node *orig_node,
				  const void *tt_buff, u16 tt_num_vlan,
				  struct batadv_tvlv_tt_change *tt_change,
				  u16 tt_num_changes, u8 ttvn)
{
	u8 orig_ttvn = READ_ONCE(orig_node->last_ttvn);
	struct batadv_tvlv_tt_vlan_data *tt_vlan;
	bool full_table = true;
	bool has_tt_init;

	tt_vlan = (struct batadv_tvlv_tt_vlan_data *)tt_buff;
	has_tt_init = test_bit(BATADV_ORIG_CAPA_HAS_TT,
			       &orig_node->capa_initialized);

	/* orig table not initialised AND first diff is in the OGM OR the ttvn
	 * increased by one -> we can apply the attached changes
	 */
	if ((!has_tt_init && ttvn == 1) || ttvn - orig_ttvn == 1) {
		/* the OGM could not contain the changes due to their size or
		 * because they have already been sent BATADV_TT_OGM_APPEND_MAX
		 * times.
		 * In this case send a tt request
		 */
		if (!tt_num_changes) {
			full_table = false;
			goto request_table;
		}

		spin_lock_bh(&orig_node->tt_lock);

		batadv_tt_update_changes(bat_priv, orig_node, tt_num_changes,
					 ttvn, tt_change);

		/* Even if we received the precomputed crc with the OGM, we
		 * prefer to recompute it to spot any possible inconsistency
		 * in the global table
		 */
		batadv_tt_global_update_crc(bat_priv, orig_node);

		spin_unlock_bh(&orig_node->tt_lock);

		/* The ttvn alone is not enough to guarantee consistency
		 * because a single value could represent different states
		 * (due to the wrap around). Thus a node has to check whether
		 * the resulting table (after applying the changes) is still
		 * consistent or not. E.g. a node could disconnect while its
		 * ttvn is X and reconnect on ttvn = X + TTVN_MAX: in this case
		 * checking the CRC value is mandatory to detect the
		 * inconsistency
		 */
		if (!batadv_tt_global_check_crc(orig_node, tt_vlan,
						tt_num_vlan))
			goto request_table;
	} else {
		/* if we missed more than one change or our tables are not
		 * in sync anymore -> request fresh tt data
		 */
		if (!has_tt_init || ttvn != orig_ttvn ||
		    !batadv_tt_global_check_crc(orig_node, tt_vlan,
						tt_num_vlan)) {
request_table:
			batadv_dbg(BATADV_DBG_TT, bat_priv,
				   "TT inconsistency for %pM. Need to retrieve the correct information (ttvn: %u last_ttvn: %u num_changes: %u)\n",
				   orig_node->orig, ttvn, orig_ttvn,
				   tt_num_changes);
			batadv_send_tt_request(bat_priv, orig_node, ttvn,
					       tt_vlan, tt_num_vlan,
					       full_table);
			return;
		}
	}
}

/**
 * batadv_tt_global_client_is_roaming() - check if a client is marked as roaming
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the client to check
 * @vid: VLAN identifier
 *
 * Return: true if we know that the client has moved from its old originator
 * to another one. This entry is still kept for consistency purposes and will be
 * deleted later by a DEL or because of timeout
 */
bool batadv_tt_global_client_is_roaming(struct batadv_priv *bat_priv,
					u8 *addr, unsigned short vid)
{
	struct batadv_tt_global_entry *tt_global_entry;
	bool ret = false;

	tt_global_entry = batadv_tt_global_hash_find(bat_priv, addr, vid);
	if (!tt_global_entry)
		goto out;

	ret = tt_global_entry->common.flags & BATADV_TT_CLIENT_ROAM;
	batadv_tt_global_entry_put(tt_global_entry);
out:
	return ret;
}

/**
 * batadv_tt_local_client_is_roaming() - tells whether the client is roaming
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the local client to query
 * @vid: VLAN identifier
 *
 * Return: 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,
				       u8 *addr, unsigned short vid)
{
	struct batadv_tt_local_entry *tt_local_entry;
	bool ret = false;

	tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid);
	if (!tt_local_entry)
		goto out;

	ret = tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM;
	batadv_tt_local_entry_put(tt_local_entry);
out:
	return ret;
}

/**
 * batadv_tt_add_temporary_global_entry() - Add temporary entry to global TT
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: orig node which the temporary entry should be associated with
 * @addr: mac address of the client
 * @vid: VLAN id of the new temporary global translation table
 *
 * Return: true when temporary tt entry could be added, false otherwise
 */
bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig_node,
					  const unsigned char *addr,
					  unsigned short vid)
{
	/* ignore loop detect macs, they are not supposed to be in the tt local
	 * data as well.
	 */
	if (batadv_bla_is_loopdetect_mac(addr))
		return false;

	if (!batadv_tt_global_add(bat_priv, orig_node, addr, vid,
				  BATADV_TT_CLIENT_TEMP,
				  READ_ONCE(orig_node->last_ttvn)))
		return false;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Added temporary global client (addr: %pM, vid: %d, orig: %pM)\n",
		   addr, batadv_print_vid(vid), orig_node->orig);

	return true;
}

/**
 * batadv_tt_local_resize_to_mtu() - resize the local translation table fit the
 *  maximum packet size that can be transported through the mesh
 * @mesh_iface: netdev struct of the mesh interface
 *
 * Remove entries older than 'timeout' and half timeout if more entries need
 * to be removed.
 */
void batadv_tt_local_resize_to_mtu(struct net_device *mesh_iface)
{
	struct batadv_priv *bat_priv = netdev_priv(mesh_iface);
	int timeout = BATADV_TT_LOCAL_TIMEOUT / 2;
	bool reduced = false;
	int packet_size_max;
	int table_size;

	packet_size_max = READ_ONCE(bat_priv->packet_size_max);

	spin_lock_bh(&bat_priv->tt.commit_lock);

	while (timeout) {
		table_size = batadv_tt_local_table_transmit_size(bat_priv);
		if (packet_size_max >= table_size)
			break;

		batadv_tt_local_purge(bat_priv, timeout);
		batadv_tt_local_purge_pending_clients(bat_priv);

		timeout /= 2;
		reduced = true;
		net_ratelimited_function(batadv_info, mesh_iface,
					 "Forced to purge local tt entries to fit new maximum fragment MTU (%i)\n",
					 packet_size_max);
	}

	/* commit these changes immediately, to avoid synchronization problem
	 * with the TTVN
	 */
	if (reduced)
		batadv_tt_local_commit_changes_nolock(bat_priv);

	spin_unlock_bh(&bat_priv->tt.commit_lock);
}

/**
 * batadv_tt_tvlv_ogm_handler_v1() - process incoming tt tvlv container
 * @bat_priv: the bat priv with all the mesh 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 gateway data
 * @tvlv_value_len: tvlv buffer length
 */
static void batadv_tt_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig,
					  u8 flags, void *tvlv_value,
					  u16 tvlv_value_len)
{
	struct batadv_tvlv_tt_change *tt_change;
	struct batadv_tvlv_tt_data *tt_data;
	size_t tt_data_sz;
	u16 num_entries;
	u16 num_vlan;

	if (tvlv_value_len < sizeof(*tt_data))
		return;

	tt_data = tvlv_value;
	num_vlan = ntohs(tt_data->num_vlan);

	tt_data_sz = struct_size(tt_data, vlan_data, num_vlan);
	if (tvlv_value_len < tt_data_sz)
		return;

	tt_change = (struct batadv_tvlv_tt_change *)((void *)tt_data
						     + tt_data_sz);
	tvlv_value_len -= tt_data_sz;

	num_entries = batadv_tt_entries(tvlv_value_len);

	batadv_tt_update_orig(bat_priv, orig, tt_data->vlan_data, num_vlan,
			      tt_change, num_entries, tt_data->ttvn);
}

/**
 * batadv_tt_tvlv_unicast_handler_v1() - process incoming (unicast) tt tvlv
 *  container
 * @bat_priv: the bat priv with all the mesh interface information
 * @src: mac address of tt tvlv sender
 * @dst: mac address of tt tvlv recipient
 * @tvlv_value: tvlv buffer containing the tt data
 * @tvlv_value_len: tvlv buffer length
 *
 * Return: NET_RX_DROP if the tt tvlv is to be re-routed, NET_RX_SUCCESS
 * otherwise.
 */
static int batadv_tt_tvlv_unicast_handler_v1(struct batadv_priv *bat_priv,
					     u8 *src, u8 *dst,
					     void *tvlv_value,
					     u16 tvlv_value_len)
{
	struct batadv_tvlv_tt_data *tt_data;
	u16 tt_num_entries;
	size_t tt_vlan_len;
	char tt_flag;
	bool ret;

	if (tvlv_value_len < sizeof(*tt_data))
		return NET_RX_SUCCESS;

	tt_data = tvlv_value;
	tvlv_value_len -= sizeof(*tt_data);

	tt_vlan_len = flex_array_size(tt_data, vlan_data,
				      ntohs(tt_data->num_vlan));

	if (tvlv_value_len < tt_vlan_len)
		return NET_RX_SUCCESS;

	tvlv_value_len -= tt_vlan_len;
	tt_num_entries = batadv_tt_entries(tvlv_value_len);

	switch (tt_data->flags & BATADV_TT_DATA_TYPE_MASK) {
	case BATADV_TT_REQUEST:
		batadv_inc_counter(bat_priv, BATADV_CNT_TT_REQUEST_RX);

		/* If this node cannot provide a TT response the tt_request is
		 * forwarded
		 */
		ret = batadv_send_tt_response(bat_priv, tt_data, src, dst);
		if (!ret) {
			if (tt_data->flags & BATADV_TT_FULL_TABLE)
				tt_flag = 'F';
			else
				tt_flag = '.';

			batadv_dbg(BATADV_DBG_TT, bat_priv,
				   "Routing TT_REQUEST to %pM [%c]\n",
				   dst, tt_flag);
			/* tvlv API will re-route the packet */
			return NET_RX_DROP;
		}
		break;
	case BATADV_TT_RESPONSE:
		batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_RX);

		if (batadv_is_my_mac(bat_priv, dst)) {
			batadv_handle_tt_response(bat_priv, tt_data,
						  src, tt_num_entries);
			return NET_RX_SUCCESS;
		}

		if (tt_data->flags & BATADV_TT_FULL_TABLE)
			tt_flag =  'F';
		else
			tt_flag = '.';

		batadv_dbg(BATADV_DBG_TT, bat_priv,
			   "Routing TT_RESPONSE to %pM [%c]\n", dst, tt_flag);

		/* tvlv API will re-route the packet */
		return NET_RX_DROP;
	}

	return NET_RX_SUCCESS;
}

/**
 * batadv_roam_tvlv_unicast_handler_v1() - process incoming tt roam tvlv
 *  container
 * @bat_priv: the bat priv with all the mesh interface information
 * @src: mac address of tt tvlv sender
 * @dst: mac address of tt tvlv recipient
 * @tvlv_value: tvlv buffer containing the tt data
 * @tvlv_value_len: tvlv buffer length
 *
 * Return: NET_RX_DROP if the tt roam tvlv is to be re-routed, NET_RX_SUCCESS
 * otherwise.
 */
static int batadv_roam_tvlv_unicast_handler_v1(struct batadv_priv *bat_priv,
					       u8 *src, u8 *dst,
					       void *tvlv_value,
					       u16 tvlv_value_len)
{
	struct batadv_orig_node *orig_node = NULL;
	struct batadv_tvlv_roam_adv *roaming_adv;

	/* If this node is not the intended recipient of the
	 * roaming advertisement the packet is forwarded
	 * (the tvlv API will re-route the packet).
	 */
	if (!batadv_is_my_mac(bat_priv, dst))
		return NET_RX_DROP;

	if (tvlv_value_len < sizeof(*roaming_adv))
		goto out;

	orig_node = batadv_orig_hash_find(bat_priv, src);
	if (!orig_node)
		goto out;

	batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_RX);
	roaming_adv = tvlv_value;

	batadv_dbg(BATADV_DBG_TT, bat_priv,
		   "Received ROAMING_ADV from %pM (client %pM)\n",
		   src, roaming_adv->client);

	batadv_tt_global_add(bat_priv, orig_node, roaming_adv->client,
			     ntohs(roaming_adv->vid), BATADV_TT_CLIENT_ROAM,
			     READ_ONCE(orig_node->last_ttvn) + 1);

out:
	batadv_orig_node_put(orig_node);
	return NET_RX_SUCCESS;
}

/**
 * batadv_tt_init() - initialise the translation table internals
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Return: 0 on success or negative error number in case of failure.
 */
int batadv_tt_init(struct batadv_priv *bat_priv)
{
	int ret;

	/* synchronized flags must be remote */
	BUILD_BUG_ON(!(BATADV_TT_SYNC_MASK & BATADV_TT_REMOTE_MASK));

	ret = batadv_tt_local_init(bat_priv);
	if (ret < 0)
		return ret;

	ret = batadv_tt_global_init(bat_priv);
	if (ret < 0) {
		batadv_tt_local_table_free(bat_priv);
		return ret;
	}

	batadv_tvlv_handler_register(bat_priv, batadv_tt_tvlv_ogm_handler_v1,
				     batadv_tt_tvlv_unicast_handler_v1, NULL,
				     BATADV_TVLV_TT, 1, BATADV_NO_FLAGS);

	batadv_tvlv_handler_register(bat_priv, NULL,
				     batadv_roam_tvlv_unicast_handler_v1, NULL,
				     BATADV_TVLV_ROAM, 1, BATADV_NO_FLAGS);

	INIT_DELAYED_WORK(&bat_priv->tt.work, batadv_tt_purge);
	queue_delayed_work(batadv_event_workqueue, &bat_priv->tt.work,
			   msecs_to_jiffies(BATADV_TT_WORK_PERIOD));

	return 1;
}

/**
 * batadv_tt_global_is_isolated() - check if a client is marked as isolated
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the client
 * @vid: the identifier of the VLAN where this client is connected
 *
 * Return: true if the client is marked with the TT_CLIENT_ISOLA flag, false
 * otherwise
 */
bool batadv_tt_global_is_isolated(struct batadv_priv *bat_priv,
				  const u8 *addr, unsigned short vid)
{
	struct batadv_tt_global_entry *tt;
	bool ret;

	tt = batadv_tt_global_hash_find(bat_priv, addr, vid);
	if (!tt)
		return false;

	ret = tt->common.flags & BATADV_TT_CLIENT_ISOLA;

	batadv_tt_global_entry_put(tt);

	return ret;
}

/**
 * batadv_tt_cache_init() - Initialize tt memory object cache
 *
 * Return: 0 on success or negative error number in case of failure.
 */
int __init batadv_tt_cache_init(void)
{
	size_t tt_orig_size = sizeof(struct batadv_tt_orig_list_entry);
	size_t tt_change_size = sizeof(struct batadv_tt_change_node);
	size_t tt_roam_size = sizeof(struct batadv_tt_roam_node);
	size_t tg_size = sizeof(struct batadv_tt_global_entry);
	size_t tt_req_size = sizeof(struct batadv_tt_req_node);
	size_t tl_size = sizeof(struct batadv_tt_local_entry);

	batadv_tl_cache = kmem_cache_create("batadv_tl_cache", tl_size, 0,
					    SLAB_HWCACHE_ALIGN, NULL);
	if (!batadv_tl_cache)
		return -ENOMEM;

	batadv_tg_cache = kmem_cache_create("batadv_tg_cache", tg_size, 0,
					    SLAB_HWCACHE_ALIGN, NULL);
	if (!batadv_tg_cache)
		goto err_tt_tl_destroy;

	batadv_tt_orig_cache = kmem_cache_create("batadv_tt_orig_cache",
						 tt_orig_size, 0,
						 SLAB_HWCACHE_ALIGN, NULL);
	if (!batadv_tt_orig_cache)
		goto err_tt_tg_destroy;

	batadv_tt_change_cache = kmem_cache_create("batadv_tt_change_cache",
						   tt_change_size, 0,
						   SLAB_HWCACHE_ALIGN, NULL);
	if (!batadv_tt_change_cache)
		goto err_tt_orig_destroy;

	batadv_tt_req_cache = kmem_cache_create("batadv_tt_req_cache",
						tt_req_size, 0,
						SLAB_HWCACHE_ALIGN, NULL);
	if (!batadv_tt_req_cache)
		goto err_tt_change_destroy;

	batadv_tt_roam_cache = kmem_cache_create("batadv_tt_roam_cache",
						 tt_roam_size, 0,
						 SLAB_HWCACHE_ALIGN, NULL);
	if (!batadv_tt_roam_cache)
		goto err_tt_req_destroy;

	return 0;

err_tt_req_destroy:
	kmem_cache_destroy(batadv_tt_req_cache);
	batadv_tt_req_cache = NULL;
err_tt_change_destroy:
	kmem_cache_destroy(batadv_tt_change_cache);
	batadv_tt_change_cache = NULL;
err_tt_orig_destroy:
	kmem_cache_destroy(batadv_tt_orig_cache);
	batadv_tt_orig_cache = NULL;
err_tt_tg_destroy:
	kmem_cache_destroy(batadv_tg_cache);
	batadv_tg_cache = NULL;
err_tt_tl_destroy:
	kmem_cache_destroy(batadv_tl_cache);
	batadv_tl_cache = NULL;

	return -ENOMEM;
}

/**
 * batadv_tt_cache_destroy() - Destroy tt memory object cache
 */
void batadv_tt_cache_destroy(void)
{
	kmem_cache_destroy(batadv_tl_cache);
	kmem_cache_destroy(batadv_tg_cache);
	kmem_cache_destroy(batadv_tt_orig_cache);
	kmem_cache_destroy(batadv_tt_change_cache);
	kmem_cache_destroy(batadv_tt_req_cache);
	kmem_cache_destroy(batadv_tt_roam_cache);
}