/*
 * Copyright (C) 2007-2011 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 _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 bool is_out_of_time(unsigned long starting_time, unsigned long timeout)
{
        unsigned long deadline;
        deadline = starting_time + msecs_to_jiffies(timeout);

        return time_after(jiffies, deadline);
}

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;

        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);

        /* 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;

        /* 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)
{
        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;
}

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));

        bat_dbg(DBG_TT, bat_priv, "Local tt entry (%pM) pending to be removed: "
                "%s\n", tt_local_entry->common.addr, 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 (!is_out_of_time(tt_local_entry->last_seen,
                                            TT_LOCAL_TIMEOUT * 1000))
                                continue;

                        tt_local_set_pending(bat_priv, tt_local_entry,
                                             TT_CLIENT_DEL);
                        bat_dbg(DBG_TT, bat_priv, "Local tt entry (%pM) "
                                "pending to be removed: timed out\n",
                                tt_local_entry->common.addr);
                }
                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%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_PENDING ? 'X' : '.'),
                                        (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);
}

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)
                goto out;

        if (tt_global_entry->orig_node == orig_node) {
                if (roaming) {
                        /* 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;
                        }
                }
                _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);
}

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 (!is_out_of_time(tt_global_entry->roam_at,
                                            TT_CLIENT_ROAM_TIMEOUT * 1000))
                                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;

        /* A global client marked as PENDING has already moved from that
         * originator */
        if (tt_global_entry->common.flags & TT_CLIENT_PENDING)
                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 */
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);
}

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 (is_out_of_time(node->issued_at,
                    TT_REQUEST_TIMEOUT * 1000)) {
                        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) &&
                    !is_out_of_time(tt_req_node_tmp->issued_at,
                                    TT_REQUEST_TIMEOUT * 1000))

                        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->packet_type = BAT_TT_QUERY;
        tt_request->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->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->packet_type = BAT_TT_QUERY;
        tt_response->version = COMPAT_VERSION;
        tt_response->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->packet_type = BAT_TT_QUERY;
        tt_response->version = COMPAT_VERSION;
        tt_response->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;
        }
}

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 (!is_out_of_time(node->first_time,
                                    ROAMING_MAX_TIME * 1000))
                        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 (is_out_of_time(tt_roam_node->first_time,
                                   ROAMING_MAX_TIME * 1000))
                        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;
}

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->packet_type = BAT_ROAM_ADV;
        roam_adv_packet->version = COMPAT_VERSION;
        roam_adv_packet->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;

        /* the ttvn increased by one -> we can apply the attached changes */
        if (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 (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;
                }
        }
}