translation-table.c

/*
 * Copyright (C) 2007-2012 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 *
 */

#include "main.h"
#include "translation-table.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "send.h"
#include "hash.h"
#include "originator.h"
#include "routing.h"

#include <linux/crc16.h>

static void send_roam_adv(struct bat_priv *bat_priv, uint8_t *client,
			  struct orig_node *orig_node);
static void _tt_global_del(struct bat_priv *bat_priv,
			   struct tt_global_entry *tt_global_entry,
			   const char *message);
static void tt_purge(struct work_struct *work);

/* returns 1 if they are the same mac addr */
static int compare_tt(const struct hlist_node *node, const void *data2)
{
	const void *data1 = container_of(node, struct tt_common_entry,
					 hash_entry);

	return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
}

static void tt_start_timer(struct bat_priv *bat_priv)
{
	INIT_DELAYED_WORK(&bat_priv->tt_work, tt_purge);
	queue_delayed_work(bat_event_workqueue, &bat_priv->tt_work,
			   msecs_to_jiffies(5000));
}

static struct tt_common_entry *tt_hash_find(struct hashtable_t *hash,
					    const void *data)
{
	struct hlist_head *head;
	struct hlist_node *node;
	struct tt_common_entry *tt_common_entry, *tt_common_entry_tmp = NULL;
	uint32_t index;

	if (!hash)
		return NULL;

	index = choose_orig(data, hash->size);
	head = &hash->table[index];

	rcu_read_lock();
	hlist_for_each_entry_rcu(tt_common_entry, node, head, hash_entry) {
		if (!compare_eth(tt_common_entry, data))
			continue;

		if (!atomic_inc_not_zero(&tt_common_entry->refcount))
			continue;

		tt_common_entry_tmp = tt_common_entry;
		break;
	}
	rcu_read_unlock();

	return tt_common_entry_tmp;
}

static struct tt_local_entry *tt_local_hash_find(struct bat_priv *bat_priv,
						 const void *data)
{
	struct tt_common_entry *tt_common_entry;
	struct tt_local_entry *tt_local_entry = NULL;

	tt_common_entry = tt_hash_find(bat_priv->tt_local_hash, data);
	if (tt_common_entry)
		tt_local_entry = container_of(tt_common_entry,
					      struct tt_local_entry, common);
	return tt_local_entry;
}

static struct tt_global_entry *tt_global_hash_find(struct bat_priv *bat_priv,
						   const void *data)
{
	struct tt_common_entry *tt_common_entry;
	struct tt_global_entry *tt_global_entry = NULL;

	tt_common_entry = tt_hash_find(bat_priv->tt_global_hash, data);
	if (tt_common_entry)
		tt_global_entry = container_of(tt_common_entry,
					       struct tt_global_entry, common);
	return tt_global_entry;

}

static void tt_local_entry_free_ref(struct tt_local_entry *tt_local_entry)
{
	if (atomic_dec_and_test(&tt_local_entry->common.refcount))
		kfree_rcu(tt_local_entry, common.rcu);
}

static void tt_global_entry_free_rcu(struct rcu_head *rcu)
{
	struct tt_common_entry *tt_common_entry;
	struct tt_global_entry *tt_global_entry;

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

	if (tt_global_entry->orig_node)
		orig_node_free_ref(tt_global_entry->orig_node);

	kfree(tt_global_entry);
}

static void tt_global_entry_free_ref(struct tt_global_entry *tt_global_entry)
{
	if (atomic_dec_and_test(&tt_global_entry->common.refcount))
		call_rcu(&tt_global_entry->common.rcu,
			 tt_global_entry_free_rcu);
}

static void tt_local_event(struct bat_priv *bat_priv, const uint8_t *addr,
			   uint8_t flags)
{
	struct tt_change_node *tt_change_node;

	tt_change_node = kmalloc(sizeof(*tt_change_node), GFP_ATOMIC);

	if (!tt_change_node)
		return;

	tt_change_node->change.flags = flags;
	memcpy(tt_change_node->change.addr, addr, ETH_ALEN);

	spin_lock_bh(&bat_priv->tt_changes_list_lock);
	/* track the change in the OGMinterval list */
	list_add_tail(&tt_change_node->list, &bat_priv->tt_changes_list);
	atomic_inc(&bat_priv->tt_local_changes);
	spin_unlock_bh(&bat_priv->tt_changes_list_lock);

	atomic_set(&bat_priv->tt_ogm_append_cnt, 0);
}

int tt_len(int changes_num)
{
	return changes_num * sizeof(struct tt_change);
}

static int tt_local_init(struct bat_priv *bat_priv)
{
	if (bat_priv->tt_local_hash)
		return 1;

	bat_priv->tt_local_hash = hash_new(1024);

	if (!bat_priv->tt_local_hash)
		return 0;

	return 1;
}

void tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
		  int ifindex)
{
	struct bat_priv *bat_priv = netdev_priv(soft_iface);
	struct tt_local_entry *tt_local_entry = NULL;
	struct tt_global_entry *tt_global_entry = NULL;
	int hash_added;

	tt_local_entry = tt_local_hash_find(bat_priv, addr);

	if (tt_local_entry) {
		tt_local_entry->last_seen = jiffies;
		goto out;
	}

	tt_local_entry = kmalloc(sizeof(*tt_local_entry), GFP_ATOMIC);
	if (!tt_local_entry)
		goto out;

	bat_dbg(DBG_TT, bat_priv,
		"Creating new local tt entry: %pM (ttvn: %d)\n", addr,
		(uint8_t)atomic_read(&bat_priv->ttvn));

	memcpy(tt_local_entry->common.addr, addr, ETH_ALEN);
	tt_local_entry->common.flags = NO_FLAGS;
	if (is_wifi_iface(ifindex))
		tt_local_entry->common.flags |= TT_CLIENT_WIFI;
	atomic_set(&tt_local_entry->common.refcount, 2);
	tt_local_entry->last_seen = jiffies;

	/* the batman interface mac address should never be purged */
	if (compare_eth(addr, soft_iface->dev_addr))
		tt_local_entry->common.flags |= TT_CLIENT_NOPURGE;

	/* 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_entry->common.flags |= TT_CLIENT_NEW;

	hash_added = hash_add(bat_priv->tt_local_hash, compare_tt, choose_orig,
			 &tt_local_entry->common,
			 &tt_local_entry->common.hash_entry);

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

	tt_local_event(bat_priv, addr, tt_local_entry->common.flags);

	/* remove address from global hash if present */
	tt_global_entry = tt_global_hash_find(bat_priv, addr);

	/* Check whether it is a roaming! */
	if (tt_global_entry) {
		/* This node is probably going to update its tt table */
		tt_global_entry->orig_node->tt_poss_change = true;
		/* The global entry has to be marked as ROAMING and has to be
		 * kept for consistency purpose */
		tt_global_entry->common.flags |= TT_CLIENT_ROAM;
		tt_global_entry->roam_at = jiffies;
		send_roam_adv(bat_priv, tt_global_entry->common.addr,
			      tt_global_entry->orig_node);
	}
out:
	if (tt_local_entry)
		tt_local_entry_free_ref(tt_local_entry);
	if (tt_global_entry)
		tt_global_entry_free_ref(tt_global_entry);
}

int tt_changes_fill_buffer(struct bat_priv *bat_priv,
			   unsigned char *buff, int buff_len)
{
	int count = 0, tot_changes = 0;
	struct tt_change_node *entry, *safe;

	if (buff_len > 0)
		tot_changes = buff_len / tt_len(1);

	spin_lock_bh(&bat_priv->tt_changes_list_lock);
	atomic_set(&bat_priv->tt_local_changes, 0);

	list_for_each_entry_safe(entry, safe, &bat_priv->tt_changes_list,
				 list) {
		if (count < tot_changes) {
			memcpy(buff + tt_len(count),
			       &entry->change, sizeof(struct tt_change));
			count++;
		}
		list_del(&entry->list);
		kfree(entry);
	}
	spin_unlock_bh(&bat_priv->tt_changes_list_lock);

	/* Keep the buffer for possible tt_request */
	spin_lock_bh(&bat_priv->tt_buff_lock);
	kfree(bat_priv->tt_buff);
	bat_priv->tt_buff_len = 0;
	bat_priv->tt_buff = NULL;
	/* We check whether this new OGM has no changes due to size
	 * problems */
	if (buff_len > 0) {
		/**
		 * if kmalloc() fails we will reply with the full table
		 * instead of providing the diff
		 */
		bat_priv->tt_buff = kmalloc(buff_len, GFP_ATOMIC);
		if (bat_priv->tt_buff) {
			memcpy(bat_priv->tt_buff, buff, buff_len);
			bat_priv->tt_buff_len = buff_len;
		}
	}
	spin_unlock_bh(&bat_priv->tt_buff_lock);

	return tot_changes;
}

int tt_local_seq_print_text(struct seq_file *seq, void *offset)
{
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct bat_priv *bat_priv = netdev_priv(net_dev);
	struct hashtable_t *hash = bat_priv->tt_local_hash;
	struct tt_common_entry *tt_common_entry;
	struct hard_iface *primary_if;
	struct hlist_node *node;
	struct hlist_head *head;
	uint32_t i;
	int ret = 0;

	primary_if = primary_if_get_selected(bat_priv);
	if (!primary_if) {
		ret = seq_printf(seq,
				 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
				 net_dev->name);
		goto out;
	}

	if (primary_if->if_status != IF_ACTIVE) {
		ret = seq_printf(seq,
				 "BATMAN mesh %s disabled - primary interface not active\n",
				 net_dev->name);
		goto out;
	}

	seq_printf(seq,
		   "Locally retrieved addresses (from %s) announced via TT (TTVN: %u):\n",
		   net_dev->name, (uint8_t)atomic_read(&bat_priv->ttvn));

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry, node,
					 head, hash_entry) {
			seq_printf(seq, " * %pM [%c%c%c%c%c]\n",
				   tt_common_entry->addr,
				   (tt_common_entry->flags &
				    TT_CLIENT_ROAM ? 'R' : '.'),
				   (tt_common_entry->flags &
				    TT_CLIENT_NOPURGE ? 'P' : '.'),
				   (tt_common_entry->flags &
				    TT_CLIENT_NEW ? 'N' : '.'),
				   (tt_common_entry->flags &
				    TT_CLIENT_PENDING ? 'X' : '.'),
				   (tt_common_entry->flags &
				    TT_CLIENT_WIFI ? 'W' : '.'));
		}
		rcu_read_unlock();
	}
out:
	if (primary_if)
		hardif_free_ref(primary_if);
	return ret;
}

static void tt_local_set_pending(struct bat_priv *bat_priv,
				 struct tt_local_entry *tt_local_entry,
				 uint16_t flags, const char *message)
{
	tt_local_event(bat_priv, tt_local_entry->common.addr,
		       tt_local_entry->common.flags | 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 |= TT_CLIENT_PENDING;

	bat_dbg(DBG_TT, bat_priv,
		"Local tt entry (%pM) pending to be removed: %s\n",
		tt_local_entry->common.addr, message);
}

void tt_local_remove(struct bat_priv *bat_priv, const uint8_t *addr,
		     const char *message, bool roaming)
{
	struct tt_local_entry *tt_local_entry = NULL;

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

	tt_local_set_pending(bat_priv, tt_local_entry, TT_CLIENT_DEL |
			     (roaming ? TT_CLIENT_ROAM : NO_FLAGS), message);
out:
	if (tt_local_entry)
		tt_local_entry_free_ref(tt_local_entry);
}

static void tt_local_purge(struct bat_priv *bat_priv)
{
	struct hashtable_t *hash = bat_priv->tt_local_hash;
	struct tt_local_entry *tt_local_entry;
	struct tt_common_entry *tt_common_entry;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	spinlock_t *list_lock; /* protects write access to the hash lists */
	uint32_t 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_entry, node, node_tmp,
					  head, hash_entry) {
			tt_local_entry = container_of(tt_common_entry,
						      struct tt_local_entry,
						      common);
			if (tt_local_entry->common.flags & TT_CLIENT_NOPURGE)
				continue;

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

			if (!has_timed_out(tt_local_entry->last_seen,
					   TT_LOCAL_TIMEOUT))
				continue;

			tt_local_set_pending(bat_priv, tt_local_entry,
					     TT_CLIENT_DEL, "timed out");
		}
		spin_unlock_bh(list_lock);
	}

}

static void tt_local_table_free(struct bat_priv *bat_priv)
{
	struct hashtable_t *hash;
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct tt_common_entry *tt_common_entry;
	struct tt_local_entry *tt_local_entry;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	uint32_t 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, node_tmp,
					  head, hash_entry) {
			hlist_del_rcu(node);
			tt_local_entry = container_of(tt_common_entry,
						      struct tt_local_entry,
						      common);
			tt_local_entry_free_ref(tt_local_entry);
		}
		spin_unlock_bh(list_lock);
	}

	hash_destroy(hash);

	bat_priv->tt_local_hash = NULL;
}

static int tt_global_init(struct bat_priv *bat_priv)
{
	if (bat_priv->tt_global_hash)
		return 1;

	bat_priv->tt_global_hash = hash_new(1024);

	if (!bat_priv->tt_global_hash)
		return 0;

	return 1;
}

static void tt_changes_list_free(struct bat_priv *bat_priv)
{
	struct tt_change_node *entry, *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);
		kfree(entry);
	}

	atomic_set(&bat_priv->tt_local_changes, 0);
	spin_unlock_bh(&bat_priv->tt_changes_list_lock);
}

/* caller must hold orig_node refcount */
int tt_global_add(struct bat_priv *bat_priv, struct orig_node *orig_node,
		  const unsigned char *tt_addr, uint8_t ttvn, bool roaming,
		  bool wifi)
{
	struct tt_global_entry *tt_global_entry;
	struct orig_node *orig_node_tmp;
	int ret = 0;
	int hash_added;

	tt_global_entry = tt_global_hash_find(bat_priv, tt_addr);

	if (!tt_global_entry) {
		tt_global_entry =
			kmalloc(sizeof(*tt_global_entry),
				GFP_ATOMIC);
		if (!tt_global_entry)
			goto out;

		memcpy(tt_global_entry->common.addr, tt_addr, ETH_ALEN);
		tt_global_entry->common.flags = NO_FLAGS;
		atomic_set(&tt_global_entry->common.refcount, 2);
		/* Assign the new orig_node */
		atomic_inc(&orig_node->refcount);
		tt_global_entry->orig_node = orig_node;
		tt_global_entry->ttvn = ttvn;
		tt_global_entry->roam_at = 0;

		hash_added = hash_add(bat_priv->tt_global_hash, compare_tt,
				 choose_orig, &tt_global_entry->common,
				 &tt_global_entry->common.hash_entry);

		if (unlikely(hash_added != 0)) {
			/* remove the reference for the hash */
			tt_global_entry_free_ref(tt_global_entry);
			goto out_remove;
		}
		atomic_inc(&orig_node->tt_size);
	} else {
		if (tt_global_entry->orig_node != orig_node) {
			atomic_dec(&tt_global_entry->orig_node->tt_size);
			orig_node_tmp = tt_global_entry->orig_node;
			atomic_inc(&orig_node->refcount);
			tt_global_entry->orig_node = orig_node;
			orig_node_free_ref(orig_node_tmp);
			atomic_inc(&orig_node->tt_size);
		}
		tt_global_entry->common.flags = NO_FLAGS;
		tt_global_entry->ttvn = ttvn;
		tt_global_entry->roam_at = 0;
	}

	if (wifi)
		tt_global_entry->common.flags |= TT_CLIENT_WIFI;

	bat_dbg(DBG_TT, bat_priv,
		"Creating new global tt entry: %pM (via %pM)\n",
		tt_global_entry->common.addr, orig_node->orig);

out_remove:
	/* remove address from local hash if present */
	tt_local_remove(bat_priv, tt_global_entry->common.addr,
			"global tt received", roaming);
	ret = 1;
out:
	if (tt_global_entry)
		tt_global_entry_free_ref(tt_global_entry);
	return ret;
}

int tt_global_seq_print_text(struct seq_file *seq, void *offset)
{
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct bat_priv *bat_priv = netdev_priv(net_dev);
	struct hashtable_t *hash = bat_priv->tt_global_hash;
	struct tt_common_entry *tt_common_entry;
	struct tt_global_entry *tt_global_entry;
	struct hard_iface *primary_if;
	struct hlist_node *node;
	struct hlist_head *head;
	uint32_t i;
	int ret = 0;

	primary_if = primary_if_get_selected(bat_priv);
	if (!primary_if) {
		ret = seq_printf(seq,
				 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
				 net_dev->name);
		goto out;
	}

	if (primary_if->if_status != IF_ACTIVE) {
		ret = seq_printf(seq,
				 "BATMAN mesh %s disabled - primary interface not active\n",
				 net_dev->name);
		goto out;
	}

	seq_printf(seq,
		   "Globally announced TT entries received via the mesh %s\n",
		   net_dev->name);
	seq_printf(seq, "       %-13s %s       %-15s %s %s\n",
		   "Client", "(TTVN)", "Originator", "(Curr TTVN)", "Flags");

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry, node,
					 head, hash_entry) {
			tt_global_entry = container_of(tt_common_entry,
						       struct tt_global_entry,
						       common);
			seq_printf(seq,
				   " * %pM  (%3u) via %pM     (%3u)   [%c%c]\n",
				   tt_global_entry->common.addr,
				   tt_global_entry->ttvn,
				   tt_global_entry->orig_node->orig,
				   (uint8_t) atomic_read(
						&tt_global_entry->orig_node->
						last_ttvn),
				   (tt_global_entry->common.flags &
				    TT_CLIENT_ROAM ? 'R' : '.'),
				   (tt_global_entry->common.flags &
				    TT_CLIENT_WIFI ? 'W' : '.'));
		}
		rcu_read_unlock();
	}
out:
	if (primary_if)
		hardif_free_ref(primary_if);
	return ret;
}

static void _tt_global_del(struct bat_priv *bat_priv,
			   struct tt_global_entry *tt_global_entry,
			   const char *message)
{
	if (!tt_global_entry)
		goto out;

	bat_dbg(DBG_TT, bat_priv,
		"Deleting global tt entry %pM (via %pM): %s\n",
		tt_global_entry->common.addr, tt_global_entry->orig_node->orig,
		message);

	atomic_dec(&tt_global_entry->orig_node->tt_size);

	hash_remove(bat_priv->tt_global_hash, compare_tt, choose_orig,
		    tt_global_entry->common.addr);
out:
	if (tt_global_entry)
		tt_global_entry_free_ref(tt_global_entry);
}

static void tt_global_del(struct bat_priv *bat_priv,
			  struct orig_node *orig_node,
			  const unsigned char *addr,
			  const char *message, bool roaming)
{
	struct tt_global_entry *tt_global_entry = NULL;
	struct tt_local_entry *tt_local_entry = NULL;

	tt_global_entry = tt_global_hash_find(bat_priv, addr);
	if (!tt_global_entry || tt_global_entry->orig_node != orig_node)
		goto out;

	if (!roaming)
		goto out_del;

	/* 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 => we mark
	 *    it with TT_CLIENT_ROAM, we start a timer and we
	 *    wait for node B to claim it. In case of timeout
	 *    the entry is purged.
	 * 2) the client roamed to us => we can directly delete
	 *    the global entry, since it is useless now. */
	tt_local_entry = tt_local_hash_find(bat_priv,
					    tt_global_entry->common.addr);
	if (!tt_local_entry) {
		tt_global_entry->common.flags |= TT_CLIENT_ROAM;
		tt_global_entry->roam_at = jiffies;
		goto out;
	}

out_del:
	_tt_global_del(bat_priv, tt_global_entry, message);

out:
	if (tt_global_entry)
		tt_global_entry_free_ref(tt_global_entry);
	if (tt_local_entry)
		tt_local_entry_free_ref(tt_local_entry);
}

void tt_global_del_orig(struct bat_priv *bat_priv,
			struct orig_node *orig_node, const char *message)
{
	struct tt_global_entry *tt_global_entry;
	struct tt_common_entry *tt_common_entry;
	uint32_t i;
	struct hashtable_t *hash = bat_priv->tt_global_hash;
	struct hlist_node *node, *safe;
	struct hlist_head *head;
	spinlock_t *list_lock; /* protects write access to the hash lists */

	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, node, safe,
					  head, hash_entry) {
			tt_global_entry = container_of(tt_common_entry,
						       struct tt_global_entry,
						       common);
			if (tt_global_entry->orig_node == orig_node) {
				bat_dbg(DBG_TT, bat_priv,
					"Deleting global tt entry %pM (via %pM): %s\n",
					tt_global_entry->common.addr,
					tt_global_entry->orig_node->orig,
					message);
				hlist_del_rcu(node);
				tt_global_entry_free_ref(tt_global_entry);
			}
		}
		spin_unlock_bh(list_lock);
	}
	atomic_set(&orig_node->tt_size, 0);
	orig_node->tt_initialised = false;
}

static void tt_global_roam_purge(struct bat_priv *bat_priv)
{
	struct hashtable_t *hash = bat_priv->tt_global_hash;
	struct tt_common_entry *tt_common_entry;
	struct tt_global_entry *tt_global_entry;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	spinlock_t *list_lock; /* protects write access to the hash lists */
	uint32_t 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_entry, node, node_tmp,
					  head, hash_entry) {
			tt_global_entry = container_of(tt_common_entry,
						       struct tt_global_entry,
						       common);
			if (!(tt_global_entry->common.flags & TT_CLIENT_ROAM))
				continue;
			if (!has_timed_out(tt_global_entry->roam_at,
					   TT_CLIENT_ROAM_TIMEOUT))
				continue;

			bat_dbg(DBG_TT, bat_priv,
				"Deleting global tt entry (%pM): Roaming timeout\n",
				tt_global_entry->common.addr);
			atomic_dec(&tt_global_entry->orig_node->tt_size);
			hlist_del_rcu(node);
			tt_global_entry_free_ref(tt_global_entry);
		}
		spin_unlock_bh(list_lock);
	}

}

static void tt_global_table_free(struct bat_priv *bat_priv)
{
	struct hashtable_t *hash;
	spinlock_t *list_lock; /* protects write access to the hash lists */
	struct tt_common_entry *tt_common_entry;
	struct tt_global_entry *tt_global_entry;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	uint32_t 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, node_tmp,
					  head, hash_entry) {
			hlist_del_rcu(node);
			tt_global_entry = container_of(tt_common_entry,
						       struct tt_global_entry,
						       common);
			tt_global_entry_free_ref(tt_global_entry);
		}
		spin_unlock_bh(list_lock);
	}

	hash_destroy(hash);

	bat_priv->tt_global_hash = NULL;
}

static bool _is_ap_isolated(struct tt_local_entry *tt_local_entry,
			    struct tt_global_entry *tt_global_entry)
{
	bool ret = false;

	if (tt_local_entry->common.flags & TT_CLIENT_WIFI &&
	    tt_global_entry->common.flags & TT_CLIENT_WIFI)
		ret = true;

	return ret;
}

struct orig_node *transtable_search(struct bat_priv *bat_priv,
				    const uint8_t *src, const uint8_t *addr)
{
	struct tt_local_entry *tt_local_entry = NULL;
	struct tt_global_entry *tt_global_entry = NULL;
	struct orig_node *orig_node = NULL;

	if (src && atomic_read(&bat_priv->ap_isolation)) {
		tt_local_entry = tt_local_hash_find(bat_priv, src);
		if (!tt_local_entry)
			goto out;
	}

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

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

	if (!atomic_inc_not_zero(&tt_global_entry->orig_node->refcount))
		goto out;

	orig_node = tt_global_entry->orig_node;

out:
	if (tt_global_entry)
		tt_global_entry_free_ref(tt_global_entry);
	if (tt_local_entry)
		tt_local_entry_free_ref(tt_local_entry);

	return orig_node;
}

/* Calculates the checksum of the local table of a given orig_node */
static uint16_t tt_global_crc(struct bat_priv *bat_priv,
			      struct orig_node *orig_node)
{
	uint16_t total = 0, total_one;
	struct hashtable_t *hash = bat_priv->tt_global_hash;
	struct tt_common_entry *tt_common_entry;
	struct tt_global_entry *tt_global_entry;
	struct hlist_node *node;
	struct hlist_head *head;
	uint32_t i;
	int j;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry, node,
					 head, hash_entry) {
			tt_global_entry = container_of(tt_common_entry,
						       struct tt_global_entry,
						       common);
			if (compare_eth(tt_global_entry->orig_node,
					orig_node)) {
				/* 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_entry->flags & TT_CLIENT_ROAM)
					continue;
				total_one = 0;
				for (j = 0; j < ETH_ALEN; j++)
					total_one = crc16_byte(total_one,
						tt_common_entry->addr[j]);
				total ^= total_one;
			}
		}
		rcu_read_unlock();
	}

	return total;
}

/* Calculates the checksum of the local table */
uint16_t tt_local_crc(struct bat_priv *bat_priv)
{
	uint16_t total = 0, total_one;
	struct hashtable_t *hash = bat_priv->tt_local_hash;
	struct tt_common_entry *tt_common_entry;
	struct hlist_node *node;
	struct hlist_head *head;
	uint32_t i;
	int j;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry, node,
					 head, hash_entry) {
			/* not yet committed clients have not to be taken into
			 * account while computing the CRC */
			if (tt_common_entry->flags & TT_CLIENT_NEW)
				continue;
			total_one = 0;
			for (j = 0; j < ETH_ALEN; j++)
				total_one = crc16_byte(total_one,
						   tt_common_entry->addr[j]);
			total ^= total_one;
		}
		rcu_read_unlock();
	}

	return total;
}

static void tt_req_list_free(struct bat_priv *bat_priv)
{
	struct tt_req_node *node, *safe;

	spin_lock_bh(&bat_priv->tt_req_list_lock);

	list_for_each_entry_safe(node, safe, &bat_priv->tt_req_list, list) {
		list_del(&node->list);
		kfree(node);
	}

	spin_unlock_bh(&bat_priv->tt_req_list_lock);
}

static void tt_save_orig_buffer(struct bat_priv *bat_priv,
				struct orig_node *orig_node,
				const unsigned char *tt_buff,
				uint8_t tt_num_changes)
{
	uint16_t tt_buff_len = tt_len(tt_num_changes);

	/* 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);
}

static void tt_req_purge(struct bat_priv *bat_priv)
{
	struct tt_req_node *node, *safe;

	spin_lock_bh(&bat_priv->tt_req_list_lock);
	list_for_each_entry_safe(node, safe, &bat_priv->tt_req_list, list) {
		if (has_timed_out(node->issued_at, TT_REQUEST_TIMEOUT)) {
			list_del(&node->list);
			kfree(node);
		}
	}
	spin_unlock_bh(&bat_priv->tt_req_list_lock);
}

/* returns the pointer to the new tt_req_node struct if no request
 * has already been issued for this orig_node, NULL otherwise */
static struct tt_req_node *new_tt_req_node(struct bat_priv *bat_priv,
					  struct orig_node *orig_node)
{
	struct tt_req_node *tt_req_node_tmp, *tt_req_node = NULL;

	spin_lock_bh(&bat_priv->tt_req_list_lock);
	list_for_each_entry(tt_req_node_tmp, &bat_priv->tt_req_list, list) {
		if (compare_eth(tt_req_node_tmp, orig_node) &&
		    !has_timed_out(tt_req_node_tmp->issued_at,
				   TT_REQUEST_TIMEOUT))
			goto unlock;
	}

	tt_req_node = kmalloc(sizeof(*tt_req_node), GFP_ATOMIC);
	if (!tt_req_node)
		goto unlock;

	memcpy(tt_req_node->addr, orig_node->orig, ETH_ALEN);
	tt_req_node->issued_at = jiffies;

	list_add(&tt_req_node->list, &bat_priv->tt_req_list);
unlock:
	spin_unlock_bh(&bat_priv->tt_req_list_lock);
	return tt_req_node;
}

/* data_ptr is useless here, but has to be kept to respect the prototype */
static int tt_local_valid_entry(const void *entry_ptr, const void *data_ptr)
{
	const struct tt_common_entry *tt_common_entry = entry_ptr;

	if (tt_common_entry->flags & TT_CLIENT_NEW)
		return 0;
	return 1;
}

static int tt_global_valid_entry(const void *entry_ptr, const void *data_ptr)
{
	const struct tt_common_entry *tt_common_entry = entry_ptr;
	const struct tt_global_entry *tt_global_entry;
	const struct orig_node *orig_node = data_ptr;

	if (tt_common_entry->flags & TT_CLIENT_ROAM)
		return 0;

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

	return (tt_global_entry->orig_node == orig_node);
}

static struct sk_buff *tt_response_fill_table(uint16_t tt_len, uint8_t ttvn,
					      struct hashtable_t *hash,
					      struct hard_iface *primary_if,
					      int (*valid_cb)(const void *,
							      const void *),
					      void *cb_data)
{
	struct tt_common_entry *tt_common_entry;
	struct tt_query_packet *tt_response;
	struct tt_change *tt_change;
	struct hlist_node *node;
	struct hlist_head *head;
	struct sk_buff *skb = NULL;
	uint16_t tt_tot, tt_count;
	ssize_t tt_query_size = sizeof(struct tt_query_packet);
	uint32_t i;

	if (tt_query_size + tt_len > primary_if->soft_iface->mtu) {
		tt_len = primary_if->soft_iface->mtu - tt_query_size;
		tt_len -= tt_len % sizeof(struct tt_change);
	}
	tt_tot = tt_len / sizeof(struct tt_change);

	skb = dev_alloc_skb(tt_query_size + tt_len + ETH_HLEN);
	if (!skb)
		goto out;

	skb_reserve(skb, ETH_HLEN);
	tt_response = (struct tt_query_packet *)skb_put(skb,
						     tt_query_size + tt_len);
	tt_response->ttvn = ttvn;

	tt_change = (struct tt_change *)(skb->data + tt_query_size);
	tt_count = 0;

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

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

			if ((valid_cb) && (!valid_cb(tt_common_entry, cb_data)))
				continue;

			memcpy(tt_change->addr, tt_common_entry->addr,
			       ETH_ALEN);
			tt_change->flags = NO_FLAGS;

			tt_count++;
			tt_change++;
		}
	}
	rcu_read_unlock();

	/* store in the message the number of entries we have successfully
	 * copied */
	tt_response->tt_data = htons(tt_count);

out:
	return skb;
}

static int send_tt_request(struct bat_priv *bat_priv,
			   struct orig_node *dst_orig_node,
			   uint8_t ttvn, uint16_t tt_crc, bool full_table)
{
	struct sk_buff *skb = NULL;
	struct tt_query_packet *tt_request;
	struct neigh_node *neigh_node = NULL;
	struct hard_iface *primary_if;
	struct tt_req_node *tt_req_node = NULL;
	int ret = 1;

	primary_if = 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 = new_tt_req_node(bat_priv, dst_orig_node);
	if (!tt_req_node)
		goto out;

	skb = dev_alloc_skb(sizeof(struct tt_query_packet) + ETH_HLEN);
	if (!skb)
		goto out;

	skb_reserve(skb, ETH_HLEN);

	tt_request = (struct tt_query_packet *)skb_put(skb,
				sizeof(struct tt_query_packet));

	tt_request->header.packet_type = BAT_TT_QUERY;
	tt_request->header.version = COMPAT_VERSION;
	memcpy(tt_request->src, primary_if->net_dev->dev_addr, ETH_ALEN);
	memcpy(tt_request->dst, dst_orig_node->orig, ETH_ALEN);
	tt_request->header.ttl = TTL;
	tt_request->ttvn = ttvn;
	tt_request->tt_data = tt_crc;
	tt_request->flags = TT_REQUEST;

	if (full_table)
		tt_request->flags |= TT_FULL_TABLE;

	neigh_node = orig_node_get_router(dst_orig_node);
	if (!neigh_node)
		goto out;

	bat_dbg(DBG_TT, bat_priv,
		"Sending TT_REQUEST to %pM via %pM [%c]\n",
		dst_orig_node->orig, neigh_node->addr,
		(full_table ? 'F' : '.'));

	send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
	ret = 0;

out:
	if (neigh_node)
		neigh_node_free_ref(neigh_node);
	if (primary_if)
		hardif_free_ref(primary_if);
	if (ret)
		kfree_skb(skb);
	if (ret && tt_req_node) {
		spin_lock_bh(&bat_priv->tt_req_list_lock);
		list_del(&tt_req_node->list);
		spin_unlock_bh(&bat_priv->tt_req_list_lock);
		kfree(tt_req_node);
	}
	return ret;
}

static bool send_other_tt_response(struct bat_priv *bat_priv,
				   struct tt_query_packet *tt_request)
{
	struct orig_node *req_dst_orig_node = NULL, *res_dst_orig_node = NULL;
	struct neigh_node *neigh_node = NULL;
	struct hard_iface *primary_if = NULL;
	uint8_t orig_ttvn, req_ttvn, ttvn;
	int ret = false;
	unsigned char *tt_buff;
	bool full_table;
	uint16_t tt_len, tt_tot;
	struct sk_buff *skb = NULL;
	struct tt_query_packet *tt_response;

	bat_dbg(DBG_TT, bat_priv,
		"Received TT_REQUEST from %pM for ttvn: %u (%pM) [%c]\n",
		tt_request->src, tt_request->ttvn, tt_request->dst,
		(tt_request->flags & TT_FULL_TABLE ? 'F' : '.'));

	/* Let's get the orig node of the REAL destination */
	req_dst_orig_node = orig_hash_find(bat_priv, tt_request->dst);
	if (!req_dst_orig_node)
		goto out;

	res_dst_orig_node = orig_hash_find(bat_priv, tt_request->src);
	if (!res_dst_orig_node)
		goto out;

	neigh_node = orig_node_get_router(res_dst_orig_node);
	if (!neigh_node)
		goto out;

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

	orig_ttvn = (uint8_t)atomic_read(&req_dst_orig_node->last_ttvn);
	req_ttvn = tt_request->ttvn;

	/* I don't have the requested data */
	if (orig_ttvn != req_ttvn ||
	    tt_request->tt_data != req_dst_orig_node->tt_crc)
		goto out;

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

	/* In this version, fragmentation is not implemented, then
	 * I'll send only one packet with as much TT entries as I can */
	if (!full_table) {
		spin_lock_bh(&req_dst_orig_node->tt_buff_lock);
		tt_len = req_dst_orig_node->tt_buff_len;
		tt_tot = tt_len / sizeof(struct tt_change);

		skb = dev_alloc_skb(sizeof(struct tt_query_packet) +
				    tt_len + ETH_HLEN);
		if (!skb)
			goto unlock;

		skb_reserve(skb, ETH_HLEN);
		tt_response = (struct tt_query_packet *)skb_put(skb,
				sizeof(struct tt_query_packet) + tt_len);
		tt_response->ttvn = req_ttvn;
		tt_response->tt_data = htons(tt_tot);

		tt_buff = skb->data + sizeof(struct tt_query_packet);
		/* Copy the last orig_node's OGM buffer */
		memcpy(tt_buff, req_dst_orig_node->tt_buff,
		       req_dst_orig_node->tt_buff_len);

		spin_unlock_bh(&req_dst_orig_node->tt_buff_lock);
	} else {
		tt_len = (uint16_t)atomic_read(&req_dst_orig_node->tt_size) *
						sizeof(struct tt_change);
		ttvn = (uint8_t)atomic_read(&req_dst_orig_node->last_ttvn);

		skb = tt_response_fill_table(tt_len, ttvn,
					     bat_priv->tt_global_hash,
					     primary_if, tt_global_valid_entry,
					     req_dst_orig_node);
		if (!skb)
			goto out;

		tt_response = (struct tt_query_packet *)skb->data;
	}

	tt_response->header.packet_type = BAT_TT_QUERY;
	tt_response->header.version = COMPAT_VERSION;
	tt_response->header.ttl = TTL;
	memcpy(tt_response->src, req_dst_orig_node->orig, ETH_ALEN);
	memcpy(tt_response->dst, tt_request->src, ETH_ALEN);
	tt_response->flags = TT_RESPONSE;

	if (full_table)
		tt_response->flags |= TT_FULL_TABLE;

	bat_dbg(DBG_TT, bat_priv,
		"Sending TT_RESPONSE %pM via %pM for %pM (ttvn: %u)\n",
		res_dst_orig_node->orig, neigh_node->addr,
		req_dst_orig_node->orig, req_ttvn);

	send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
	ret = true;
	goto out;

unlock:
	spin_unlock_bh(&req_dst_orig_node->tt_buff_lock);

out:
	if (res_dst_orig_node)
		orig_node_free_ref(res_dst_orig_node);
	if (req_dst_orig_node)
		orig_node_free_ref(req_dst_orig_node);
	if (neigh_node)
		neigh_node_free_ref(neigh_node);
	if (primary_if)
		hardif_free_ref(primary_if);
	if (!ret)
		kfree_skb(skb);
	return ret;

}
static bool send_my_tt_response(struct bat_priv *bat_priv,
				struct tt_query_packet *tt_request)
{
	struct orig_node *orig_node = NULL;
	struct neigh_node *neigh_node = NULL;
	struct hard_iface *primary_if = NULL;
	uint8_t my_ttvn, req_ttvn, ttvn;
	int ret = false;
	unsigned char *tt_buff;
	bool full_table;
	uint16_t tt_len, tt_tot;
	struct sk_buff *skb = NULL;
	struct tt_query_packet *tt_response;

	bat_dbg(DBG_TT, bat_priv,
		"Received TT_REQUEST from %pM for ttvn: %u (me) [%c]\n",
		tt_request->src, tt_request->ttvn,
		(tt_request->flags & TT_FULL_TABLE ? 'F' : '.'));


	my_ttvn = (uint8_t)atomic_read(&bat_priv->ttvn);
	req_ttvn = tt_request->ttvn;

	orig_node = orig_hash_find(bat_priv, tt_request->src);
	if (!orig_node)
		goto out;

	neigh_node = orig_node_get_router(orig_node);
	if (!neigh_node)
		goto out;

	primary_if = 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_request->flags & TT_FULL_TABLE || my_ttvn != req_ttvn ||
	    !bat_priv->tt_buff)
		full_table = true;
	else
		full_table = false;

	/* In this version, fragmentation is not implemented, then
	 * I'll send only one packet with as much TT entries as I can */
	if (!full_table) {
		spin_lock_bh(&bat_priv->tt_buff_lock);
		tt_len = bat_priv->tt_buff_len;
		tt_tot = tt_len / sizeof(struct tt_change);

		skb = dev_alloc_skb(sizeof(struct tt_query_packet) +
				    tt_len + ETH_HLEN);
		if (!skb)
			goto unlock;

		skb_reserve(skb, ETH_HLEN);
		tt_response = (struct tt_query_packet *)skb_put(skb,
				sizeof(struct tt_query_packet) + tt_len);
		tt_response->ttvn = req_ttvn;
		tt_response->tt_data = htons(tt_tot);

		tt_buff = skb->data + sizeof(struct tt_query_packet);
		memcpy(tt_buff, bat_priv->tt_buff,
		       bat_priv->tt_buff_len);
		spin_unlock_bh(&bat_priv->tt_buff_lock);
	} else {
		tt_len = (uint16_t)atomic_read(&bat_priv->num_local_tt) *
						sizeof(struct tt_change);
		ttvn = (uint8_t)atomic_read(&bat_priv->ttvn);

		skb = tt_response_fill_table(tt_len, ttvn,
					     bat_priv->tt_local_hash,
					     primary_if, tt_local_valid_entry,
					     NULL);
		if (!skb)
			goto out;

		tt_response = (struct tt_query_packet *)skb->data;
	}

	tt_response->header.packet_type = BAT_TT_QUERY;
	tt_response->header.version = COMPAT_VERSION;
	tt_response->header.ttl = TTL;
	memcpy(tt_response->src, primary_if->net_dev->dev_addr, ETH_ALEN);
	memcpy(tt_response->dst, tt_request->src, ETH_ALEN);
	tt_response->flags = TT_RESPONSE;

	if (full_table)
		tt_response->flags |= TT_FULL_TABLE;

	bat_dbg(DBG_TT, bat_priv,
		"Sending TT_RESPONSE to %pM via %pM [%c]\n",
		orig_node->orig, neigh_node->addr,
		(tt_response->flags & TT_FULL_TABLE ? 'F' : '.'));

	send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
	ret = true;
	goto out;

unlock:
	spin_unlock_bh(&bat_priv->tt_buff_lock);
out:
	if (orig_node)
		orig_node_free_ref(orig_node);
	if (neigh_node)
		neigh_node_free_ref(neigh_node);
	if (primary_if)
		hardif_free_ref(primary_if);
	if (!ret)
		kfree_skb(skb);
	/* This packet was for me, so it doesn't need to be re-routed */
	return true;
}

bool send_tt_response(struct bat_priv *bat_priv,
		      struct tt_query_packet *tt_request)
{
	if (is_my_mac(tt_request->dst))
		return send_my_tt_response(bat_priv, tt_request);
	else
		return send_other_tt_response(bat_priv, tt_request);
}

static void _tt_update_changes(struct bat_priv *bat_priv,
			       struct orig_node *orig_node,
			       struct tt_change *tt_change,
			       uint16_t tt_num_changes, uint8_t ttvn)
{
	int i;

	for (i = 0; i < tt_num_changes; i++) {
		if ((tt_change + i)->flags & TT_CLIENT_DEL)
			tt_global_del(bat_priv, orig_node,
				      (tt_change + i)->addr,
				      "tt removed by changes",
				      (tt_change + i)->flags & TT_CLIENT_ROAM);
		else
			if (!tt_global_add(bat_priv, orig_node,
					   (tt_change + i)->addr, ttvn, false,
					   (tt_change + i)->flags &
							TT_CLIENT_WIFI))
				/* 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;
	}
	orig_node->tt_initialised = true;
}

static void tt_fill_gtable(struct bat_priv *bat_priv,
			   struct tt_query_packet *tt_response)
{
	struct orig_node *orig_node = NULL;

	orig_node = orig_hash_find(bat_priv, tt_response->src);
	if (!orig_node)
		goto out;

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

	_tt_update_changes(bat_priv, orig_node,
			   (struct tt_change *)(tt_response + 1),
			   tt_response->tt_data, tt_response->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);

	atomic_set(&orig_node->last_ttvn, tt_response->ttvn);

out:
	if (orig_node)
		orig_node_free_ref(orig_node);
}

static void tt_update_changes(struct bat_priv *bat_priv,
			      struct orig_node *orig_node,
			      uint16_t tt_num_changes, uint8_t ttvn,
			      struct tt_change *tt_change)
{
	_tt_update_changes(bat_priv, orig_node, tt_change, tt_num_changes,
			   ttvn);

	tt_save_orig_buffer(bat_priv, orig_node, (unsigned char *)tt_change,
			    tt_num_changes);
	atomic_set(&orig_node->last_ttvn, ttvn);
}

bool is_my_client(struct bat_priv *bat_priv, const uint8_t *addr)
{
	struct tt_local_entry *tt_local_entry = NULL;
	bool ret = false;

	tt_local_entry = tt_local_hash_find(bat_priv, addr);
	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 & TT_CLIENT_PENDING)
		goto out;
	ret = true;
out:
	if (tt_local_entry)
		tt_local_entry_free_ref(tt_local_entry);
	return ret;
}

void handle_tt_response(struct bat_priv *bat_priv,
			struct tt_query_packet *tt_response)
{
	struct tt_req_node *node, *safe;
	struct orig_node *orig_node = NULL;

	bat_dbg(DBG_TT, bat_priv,
		"Received TT_RESPONSE from %pM for ttvn %d t_size: %d [%c]\n",
		tt_response->src, tt_response->ttvn, tt_response->tt_data,
		(tt_response->flags & TT_FULL_TABLE ? 'F' : '.'));

	orig_node = orig_hash_find(bat_priv, tt_response->src);
	if (!orig_node)
		goto out;

	if (tt_response->flags & TT_FULL_TABLE)
		tt_fill_gtable(bat_priv, tt_response);
	else
		tt_update_changes(bat_priv, orig_node, tt_response->tt_data,
				  tt_response->ttvn,
				  (struct tt_change *)(tt_response + 1));

	/* Delete the tt_req_node from pending tt_requests list */
	spin_lock_bh(&bat_priv->tt_req_list_lock);
	list_for_each_entry_safe(node, safe, &bat_priv->tt_req_list, list) {
		if (!compare_eth(node->addr, tt_response->src))
			continue;
		list_del(&node->list);
		kfree(node);
	}
	spin_unlock_bh(&bat_priv->tt_req_list_lock);

	/* Recalculate the CRC for this orig_node and store it */
	orig_node->tt_crc = tt_global_crc(bat_priv, orig_node);
	/* Roaming phase is over: tables are in sync again. I can
	 * unset the flag */
	orig_node->tt_poss_change = false;
out:
	if (orig_node)
		orig_node_free_ref(orig_node);
}

int tt_init(struct bat_priv *bat_priv)
{
	if (!tt_local_init(bat_priv))
		return 0;

	if (!tt_global_init(bat_priv))
		return 0;

	tt_start_timer(bat_priv);

	return 1;
}

static void tt_roam_list_free(struct bat_priv *bat_priv)
{
	struct tt_roam_node *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);
		kfree(node);
	}

	spin_unlock_bh(&bat_priv->tt_roam_list_lock);
}

static void tt_roam_purge(struct bat_priv *bat_priv)
{
	struct tt_roam_node *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 (!has_timed_out(node->first_time, ROAMING_MAX_TIME))
			continue;

		list_del(&node->list);
		kfree(node);
	}
	spin_unlock_bh(&bat_priv->tt_roam_list_lock);
}

/* 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.
 *
 * returns true if the ROAMING_ADV can be sent, false otherwise */
static bool tt_check_roam_count(struct bat_priv *bat_priv,
				uint8_t *client)
{
	struct 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 (!compare_eth(tt_roam_node->addr, client))
			continue;

		if (has_timed_out(tt_roam_node->first_time, ROAMING_MAX_TIME))
			continue;

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

	if (!ret) {
		tt_roam_node = kmalloc(sizeof(*tt_roam_node), GFP_ATOMIC);
		if (!tt_roam_node)
			goto unlock;

		tt_roam_node->first_time = jiffies;
		atomic_set(&tt_roam_node->counter, ROAMING_MAX_COUNT - 1);
		memcpy(tt_roam_node->addr, client, ETH_ALEN);

		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;
}

static void send_roam_adv(struct bat_priv *bat_priv, uint8_t *client,
			  struct orig_node *orig_node)
{
	struct neigh_node *neigh_node = NULL;
	struct sk_buff *skb = NULL;
	struct roam_adv_packet *roam_adv_packet;
	int ret = 1;
	struct hard_iface *primary_if;

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

	skb = dev_alloc_skb(sizeof(struct roam_adv_packet) + ETH_HLEN);
	if (!skb)
		goto out;

	skb_reserve(skb, ETH_HLEN);

	roam_adv_packet = (struct roam_adv_packet *)skb_put(skb,
					sizeof(struct roam_adv_packet));

	roam_adv_packet->header.packet_type = BAT_ROAM_ADV;
	roam_adv_packet->header.version = COMPAT_VERSION;
	roam_adv_packet->header.ttl = TTL;
	primary_if = primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;
	memcpy(roam_adv_packet->src, primary_if->net_dev->dev_addr, ETH_ALEN);
	hardif_free_ref(primary_if);
	memcpy(roam_adv_packet->dst, orig_node->orig, ETH_ALEN);
	memcpy(roam_adv_packet->client, client, ETH_ALEN);

	neigh_node = orig_node_get_router(orig_node);
	if (!neigh_node)
		goto out;

	bat_dbg(DBG_TT, bat_priv,
		"Sending ROAMING_ADV to %pM (client %pM) via %pM\n",
		orig_node->orig, client, neigh_node->addr);

	send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
	ret = 0;

out:
	if (neigh_node)
		neigh_node_free_ref(neigh_node);
	if (ret)
		kfree_skb(skb);
	return;
}

static void tt_purge(struct work_struct *work)
{
	struct delayed_work *delayed_work =
		container_of(work, struct delayed_work, work);
	struct bat_priv *bat_priv =
		container_of(delayed_work, struct bat_priv, tt_work);

	tt_local_purge(bat_priv);
	tt_global_roam_purge(bat_priv);
	tt_req_purge(bat_priv);
	tt_roam_purge(bat_priv);

	tt_start_timer(bat_priv);
}

void tt_free(struct bat_priv *bat_priv)
{
	cancel_delayed_work_sync(&bat_priv->tt_work);

	tt_local_table_free(bat_priv);
	tt_global_table_free(bat_priv);
	tt_req_list_free(bat_priv);
	tt_changes_list_free(bat_priv);
	tt_roam_list_free(bat_priv);

	kfree(bat_priv->tt_buff);
}

/* This function will enable or disable the specified flags for all the entries
 * in the given hash table and returns the number of modified entries */
static uint16_t tt_set_flags(struct hashtable_t *hash, uint16_t flags,
			     bool enable)
{
	uint32_t i;
	uint16_t changed_num = 0;
	struct hlist_head *head;
	struct hlist_node *node;
	struct tt_common_entry *tt_common_entry;

	if (!hash)
		goto out;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry, node,
					 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;
			}
			changed_num++;
		}
		rcu_read_unlock();
	}
out:
	return changed_num;
}

/* Purge out all the tt local entries marked with TT_CLIENT_PENDING */
static void tt_local_purge_pending_clients(struct bat_priv *bat_priv)
{
	struct hashtable_t *hash = bat_priv->tt_local_hash;
	struct tt_common_entry *tt_common_entry;
	struct tt_local_entry *tt_local_entry;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	spinlock_t *list_lock; /* protects write access to the hash lists */
	uint32_t 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, node, node_tmp,
					  head, hash_entry) {
			if (!(tt_common_entry->flags & TT_CLIENT_PENDING))
				continue;

			bat_dbg(DBG_TT, bat_priv,
				"Deleting local tt entry (%pM): pending\n",
				tt_common_entry->addr);

			atomic_dec(&bat_priv->num_local_tt);
			hlist_del_rcu(node);
			tt_local_entry = container_of(tt_common_entry,
						      struct tt_local_entry,
						      common);
			tt_local_entry_free_ref(tt_local_entry);
		}
		spin_unlock_bh(list_lock);
	}

}

void tt_commit_changes(struct bat_priv *bat_priv)
{
	uint16_t changed_num = tt_set_flags(bat_priv->tt_local_hash,
					    TT_CLIENT_NEW, false);
	/* all the reset entries have now to be effectively counted as local
	 * entries */
	atomic_add(changed_num, &bat_priv->num_local_tt);
	tt_local_purge_pending_clients(bat_priv);

	/* Increment the TTVN only once per OGM interval */
	atomic_inc(&bat_priv->ttvn);
	bat_priv->tt_poss_change = false;
}

bool is_ap_isolated(struct bat_priv *bat_priv, uint8_t *src, uint8_t *dst)
{
	struct tt_local_entry *tt_local_entry = NULL;
	struct tt_global_entry *tt_global_entry = NULL;
	bool ret = true;

	if (!atomic_read(&bat_priv->ap_isolation))
		return false;

	tt_local_entry = tt_local_hash_find(bat_priv, dst);
	if (!tt_local_entry)
		goto out;

	tt_global_entry = tt_global_hash_find(bat_priv, src);
	if (!tt_global_entry)
		goto out;

	if (_is_ap_isolated(tt_local_entry, tt_global_entry))
		goto out;

	ret = false;

out:
	if (tt_global_entry)
		tt_global_entry_free_ref(tt_global_entry);
	if (tt_local_entry)
		tt_local_entry_free_ref(tt_local_entry);
	return ret;
}

void tt_update_orig(struct bat_priv *bat_priv, struct orig_node *orig_node,
		    const unsigned char *tt_buff, uint8_t tt_num_changes,
		    uint8_t ttvn, uint16_t tt_crc)
{
	uint8_t orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
	bool full_table = true;

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

		tt_update_changes(bat_priv, orig_node, tt_num_changes, ttvn,
				  (struct tt_change *)tt_buff);

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

		/* 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 (orig_node->tt_crc != tt_crc)
			goto request_table;

		/* Roaming phase is over: tables are in sync again. I can
		 * unset the flag */
		orig_node->tt_poss_change = false;
	} else {
		/* if we missed more than one change or our tables are not
		 * in sync anymore -> request fresh tt data */
		if (!orig_node->tt_initialised || ttvn != orig_ttvn ||
		    orig_node->tt_crc != tt_crc) {
request_table:
			bat_dbg(DBG_TT, bat_priv,
				"TT inconsistency for %pM. Need to retrieve the correct information (ttvn: %u last_ttvn: %u crc: %u last_crc: %u num_changes: %u)\n",
				orig_node->orig, ttvn, orig_ttvn, tt_crc,
				orig_node->tt_crc, tt_num_changes);
			send_tt_request(bat_priv, orig_node, ttvn, tt_crc,
					full_table);
			return;
		}
	}
}