// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich, Antonio Quartulli
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

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

#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/build_bug.h>
#include <linux/byteorder/generic.h>
#include <linux/cache.h>
#include <linux/compiler.h>
#include <linux/crc32c.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <net/genetlink.h>
#include <net/netlink.h>
#include <net/sock.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>

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

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

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

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

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

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

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

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

        return hash % size;
}

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

        if (!hash)
                return NULL;

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

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

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

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

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

                tt_tmp = tt;
                break;
        }
        rcu_read_unlock();

        return tt_tmp;
}

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

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

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

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

/**
 * batadv_tt_local_entry_free_rcu() - free the tt_local_entry
 * @rcu: rcu pointer of the tt_local_entry
 */
static void batadv_tt_local_entry_free_rcu(struct rcu_head *rcu)
{
        struct batadv_tt_local_entry *tt_local_entry;

        tt_local_entry = container_of(rcu, struct batadv_tt_local_entry,
                                      common.rcu);

        kmem_cache_free(batadv_tl_cache, tt_local_entry);
}

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

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

        batadv_softif_vlan_put(tt_local_entry->vlan);

        call_rcu(&tt_local_entry->common.rcu, batadv_tt_local_entry_free_rcu);
}

/**
 * batadv_tt_local_entry_put() - decrement the tt_local_entry refcounter and
 *  possibly release it
 * @tt_local_entry: tt_local_entry to be free'd
 */
static void
batadv_tt_local_entry_put(struct batadv_tt_local_entry *tt_local_entry)
{
        kref_put(&tt_local_entry->common.refcount,
                 batadv_tt_local_entry_release);
}

/**
 * batadv_tt_global_entry_free_rcu() - free the tt_global_entry
 * @rcu: rcu pointer of the tt_global_entry
 */
static void batadv_tt_global_entry_free_rcu(struct rcu_head *rcu)
{
        struct batadv_tt_global_entry *tt_global_entry;

        tt_global_entry = container_of(rcu, struct batadv_tt_global_entry,
                                       common.rcu);

        kmem_cache_free(batadv_tg_cache, tt_global_entry);
}

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

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

        batadv_tt_global_del_orig_list(tt_global_entry);

        call_rcu(&tt_global_entry->common.rcu, batadv_tt_global_entry_free_rcu);
}

/**
 * batadv_tt_global_entry_put() - decrement the tt_global_entry refcounter and
 *  possibly release it
 * @tt_global_entry: tt_global_entry to be free'd
 */
static void
batadv_tt_global_entry_put(struct batadv_tt_global_entry *tt_global_entry)
{
        kref_put(&tt_global_entry->common.refcount,
                 batadv_tt_global_entry_release);
}

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

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

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

        return count;
}

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

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

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

        batadv_softif_vlan_put(vlan);
}

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

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

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

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

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

        batadv_orig_node_vlan_put(vlan);
}

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

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

/**
 * batadv_tt_orig_list_entry_free_rcu() - free the orig_entry
 * @rcu: rcu pointer of the orig_entry
 */
static void batadv_tt_orig_list_entry_free_rcu(struct rcu_head *rcu)
{
        struct batadv_tt_orig_list_entry *orig_entry;

        orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu);

        kmem_cache_free(batadv_tt_orig_cache, orig_entry);
}

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

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

        batadv_orig_node_put(orig_entry->orig_node);
        call_rcu(&orig_entry->rcu, batadv_tt_orig_list_entry_free_rcu);
}

/**
 * batadv_tt_orig_list_entry_put() - decrement the tt orig entry refcounter and
 *  possibly release it
 * @orig_entry: tt orig entry to be free'd
 */
static void
batadv_tt_orig_list_entry_put(struct batadv_tt_orig_list_entry *orig_entry)
{
        kref_put(&orig_entry->refcount, batadv_tt_orig_list_entry_release);
}

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

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

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

        del_op_requested = flags & BATADV_TT_CLIENT_DEL;

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

                /* DEL+ADD in the same orig interval have no effect and can be
                 * removed to avoid silly behaviour on the receiver side. The
                 * other way around (ADD+DEL) can happen in case of roaming of
                 * a client still in the NEW state. Roaming of NEW clients is
                 * now possible due to automatically recognition of "temporary"
                 * clients
                 */
                del_op_entry = entry->change.flags & BATADV_TT_CLIENT_DEL;
                if (!del_op_requested && del_op_entry)
                        goto del;
                if (del_op_requested && !del_op_entry)
                        goto del;

                /* this is a second add in the same originator interval. It
                 * means that flags have been changed: update them!
                 */
                if (!del_op_requested && !del_op_entry)
                        entry->change.flags = flags;

                continue;
del:
                list_del(&entry->list);
                kmem_cache_free(batadv_tt_change_cache, entry);
                kmem_cache_free(batadv_tt_change_cache, tt_change_node);
                event_removed = true;
                goto unlock;
        }

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

unlock:
        spin_unlock_bh(&bat_priv->tt.changes_list_lock);

        if (event_removed)
                atomic_dec(&bat_priv->tt.local_changes);
        else
                atomic_inc(&bat_priv->tt.local_changes);
}

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

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

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

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

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

        return hdr_size + batadv_tt_len(tt_local_entries);
}

static int batadv_tt_local_init(struct batadv_priv *bat_priv)
{
        if (bat_priv->tt.local_hash)
                return 0;

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

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

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

        return 0;
}

static void batadv_tt_global_free(struct batadv_priv *bat_priv,
                                  struct batadv_tt_global_entry *tt_global,
                                  const char *message)
{
        batadv_dbg(BATADV_DBG_TT, bat_priv,
                   "Deleting global tt entry %pM (vid: %d): %s\n",
                   tt_global->common.addr,
                   batadv_print_vid(tt_global->common.vid), message);

        batadv_hash_remove(bat_priv->tt.global_hash, batadv_compare_tt,
                           batadv_choose_tt, &tt_global->common);
        batadv_tt_global_entry_put(tt_global);
}

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

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

        if (in_dev)
                in_hardif = batadv_hardif_get_by_netdev(in_dev);

        tt_local = batadv_tt_local_hash_find(bat_priv, addr, vid);

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

        if (tt_local) {
                tt_local->last_seen = jiffies;
                if (tt_local->common.flags & BATADV_TT_CLIENT_PENDING) {
                        batadv_dbg(BATADV_DBG_TT, bat_priv,
                                   "Re-adding pending client %pM (vid: %d)\n",
                                   addr, batadv_print_vid(vid));
                        /* whatever the reason why the PENDING flag was set,
                         * this is a client which was enqueued to be removed in
                         * this orig_interval. Since it popped up again, the
                         * flag can be reset like it was never enqueued
                         */
                        tt_local->common.flags &= ~BATADV_TT_CLIENT_PENDING;
                        goto add_event;
                }

                if (tt_local->common.flags & BATADV_TT_CLIENT_ROAM) {
                        batadv_dbg(BATADV_DBG_TT, bat_priv,
                                   "Roaming client %pM (vid: %d) came back to its original location\n",
                                   addr, batadv_print_vid(vid));
                        /* the ROAM flag is set because this client roamed away
                         * and the node got a roaming_advertisement message. Now
                         * that the client popped up again at its original
                         * location such flag can be unset
                         */
                        tt_local->common.flags &= ~BATADV_TT_CLIENT_ROAM;
                        roamed_back = true;
                }
                goto check_roaming;
        }

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

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

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

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

        ether_addr_copy(tt_local->common.addr, addr);
        /* The local entry has to be marked as NEW to avoid to send it in
         * a full table response going out before the next ttvn increment
         * (consistency check)
         */
        tt_local->common.flags = BATADV_TT_CLIENT_NEW;
        tt_local->common.vid = vid;
        if (batadv_is_wifi_hardif(in_hardif))
                tt_local->common.flags |= BATADV_TT_CLIENT_WIFI;
        kref_init(&tt_local->common.refcount);
        tt_local->last_seen = jiffies;
        tt_local->common.added_at = tt_local->last_seen;
        tt_local->vlan = vlan;

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

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

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

add_event:
        batadv_tt_local_event(bat_priv, tt_local, BATADV_NO_FLAGS);

check_roaming:
        /* Check whether it is a roaming, but don't do anything if the roaming
         * process has already been handled
         */
        if (tt_global && !(tt_global->common.flags & BATADV_TT_CLIENT_ROAM)) {
                /* These node are probably going to update their tt table */
                head = &tt_global->orig_list;
                rcu_read_lock();
                hlist_for_each_entry_rcu(orig_entry, head, list) {
                        batadv_send_roam_adv(bat_priv, tt_global->common.addr,
                                             tt_global->common.vid,
                                             orig_entry->orig_node);
                }
                rcu_read_unlock();
                if (roamed_back) {
                        batadv_tt_global_free(bat_priv, tt_global,
                                              "Roaming canceled");
                        tt_global = NULL;
                } else {
                        /* The global entry has to be marked as ROAMING and
                         * has to be kept for consistency purpose
                         */
                        tt_global->common.flags |= BATADV_TT_CLIENT_ROAM;
                        tt_global->roam_at = jiffies;
                }
        }

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

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

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

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

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

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

        spin_lock_bh(&orig_node->vlan_list_lock);
        hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
                num_vlan++;
                num_entries += atomic_read(&vlan->tt.num_entries);
        }

        change_offset = sizeof(**tt_data);
        change_offset += num_vlan * sizeof(*tt_vlan);

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

        tvlv_len = *tt_len;
        tvlv_len += change_offset;

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

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

        tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(*tt_data + 1);
        hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
                tt_vlan->vid = htons(vlan->vid);
                tt_vlan->crc = htonl(vlan->tt.crc);

                tt_vlan++;
        }

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

out:
        spin_unlock_bh(&orig_node->vlan_list_lock);
        return tvlv_len;
}

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

        spin_lock_bh(&bat_priv->softif_vlan_list_lock);
        hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
                vlan_entries = atomic_read(&vlan->tt.num_entries);
                if (vlan_entries < 1)
                        continue;

                num_vlan++;
                total_entries += vlan_entries;
        }

        change_offset = sizeof(**tt_data);
        change_offset += num_vlan * sizeof(*tt_vlan);

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

        tvlv_len = *tt_len;
        tvlv_len += change_offset;

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

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

        tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(*tt_data + 1);
        hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
                vlan_entries = atomic_read(&vlan->tt.num_entries);
                if (vlan_entries < 1)
                        continue;

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

                tt_vlan++;
        }

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

out:
        spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
        return tvlv_len;
}

/**
 * batadv_tt_tvlv_container_update() - update the translation table tvlv
 *  container after local tt changes have been committed
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_tt_tvlv_container_update(struct batadv_priv *bat_priv)
{
        struct batadv_tt_change_node *entry, *safe;
        struct batadv_tvlv_tt_data *tt_data;
        struct batadv_tvlv_tt_change *tt_change;
        int tt_diff_len, tt_change_len = 0;

        int tt_diff_entries_num = 0;
        int tt_diff_entries_count = 0;
        u16 tvlv_len;

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

        /* if we have too many changes for one packet don't send any
         * and wait for the tt table request which will be fragmented
         */
        if (tt_diff_len > bat_priv->soft_iface->mtu)
                tt_diff_len = 0;

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

        tt_data->flags = BATADV_TT_OGM_DIFF;

        if (tt_diff_len == 0)
                goto container_register;

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

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

container_register:
        batadv_tvlv_container_register(bat_priv, BATADV_TVLV_TT, 1, tt_data,
                                       tvlv_len);
        kfree(tt_data);
}

#ifdef CONFIG_BATMAN_ADV_DEBUGFS

/**
 * batadv_tt_local_seq_print_text() - Print the local tt table in a seq file
 * @seq: seq file to print on
 * @offset: not used
 *
 * Return: always 0
 */
int batadv_tt_local_seq_print_text(struct seq_file *seq, void *offset)
{
        struct net_device *net_dev = (struct net_device *)seq->private;
        struct batadv_priv *bat_priv = netdev_priv(net_dev);
        struct batadv_hashtable *hash = bat_priv->tt.local_hash;
        struct batadv_tt_common_entry *tt_common_entry;
        struct batadv_tt_local_entry *tt_local;
        struct batadv_hard_iface *primary_if;
        struct hlist_head *head;
        u32 i;
        int last_seen_secs;
        int last_seen_msecs;
        unsigned long last_seen_jiffies;
        bool no_purge;
        u16 np_flag = BATADV_TT_CLIENT_NOPURGE;

        primary_if = batadv_seq_print_text_primary_if_get(seq);
        if (!primary_if)
                goto out;

        seq_printf(seq,
                   "Locally retrieved addresses (from %s) announced via TT (TTVN: %u):\n",
                   net_dev->name, (u8)atomic_read(&bat_priv->tt.vn));
        seq_puts(seq,
                 "       Client         VID Flags    Last seen (CRC       )\n");

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

                rcu_read_lock();
                hlist_for_each_entry_rcu(tt_common_entry,
                                         head, hash_entry) {
                        tt_local = container_of(tt_common_entry,
                                                struct batadv_tt_local_entry,
                                                common);
                        last_seen_jiffies = jiffies - tt_local->last_seen;
                        last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
                        last_seen_secs = last_seen_msecs / 1000;
                        last_seen_msecs = last_seen_msecs % 1000;

                        no_purge = tt_common_entry->flags & np_flag;
                        seq_printf(seq,
                                   " * %pM %4i [%c%c%c%c%c%c] %3u.%03u   (%#.8x)\n",
                                   tt_common_entry->addr,
                                   batadv_print_vid(tt_common_entry->vid),
                                   ((tt_common_entry->flags &
                                     BATADV_TT_CLIENT_ROAM) ? 'R' : '.'),
                                   no_purge ? 'P' : '.',
                                   ((tt_common_entry->flags &
                                     BATADV_TT_CLIENT_NEW) ? 'N' : '.'),
                                   ((tt_common_entry->flags &
                                     BATADV_TT_CLIENT_PENDING) ? 'X' : '.'),
                                   ((tt_common_entry->flags &
                                     BATADV_TT_CLIENT_WIFI) ? 'W' : '.'),
                                   ((tt_common_entry->flags &
                                     BATADV_TT_CLIENT_ISOLA) ? 'I' : '.'),
                                   no_purge ? 0 : last_seen_secs,
                                   no_purge ? 0 : last_seen_msecs,
                                   tt_local->vlan->tt.crc);
                }
                rcu_read_unlock();
        }
out:
        if (primary_if)
                batadv_hardif_put(primary_if);
        return 0;
}
#endif

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

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

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

        crc = vlan->tt.crc;

        batadv_softif_vlan_put(vlan);

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

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

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

        genlmsg_end(msg, hdr);
        return 0;

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

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

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

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

        *idx_s = 0;
        return 0;
}

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

        ifindex = batadv_netlink_get_ifindex(cb->nlh, BATADV_ATTR_MESH_IFINDEX);
        if (!ifindex)
                return -EINVAL;

        soft_iface = dev_get_by_index(net, ifindex);
        if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
                ret = -ENODEV;
                goto out;
        }

        bat_priv = netdev_priv(soft_iface);

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

        hash = bat_priv->tt.local_hash;

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

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

                bucket++;
        }

        ret = msg->len;

 out:
        if (primary_if)
                batadv_hardif_put(primary_if);
        if (soft_iface)
                dev_put(soft_iface);

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

        return ret;
}

static void
batadv_tt_local_set_pending(struct batadv_priv *bat_priv,
                            struct batadv_tt_local_entry *tt_local_entry,
                            u16 flags, const char *message)
{
        batadv_tt_local_event(bat_priv, tt_local_entry, flags);

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

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

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

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

        curr_flags = tt_local_entry->common.flags;

        flags = BATADV_TT_CLIENT_DEL;
        /* if this global entry addition is due to a roaming, the node has to
         * mark the local entry as "roamed" in order to correctly reroute
         * packets later
         */
        if (roaming) {
                flags |= BATADV_TT_CLIENT_ROAM;
                /* mark the local client as ROAMed */
                tt_local_entry->common.flags |= BATADV_TT_CLIENT_ROAM;
        }

        if (!(tt_local_entry->common.flags & BATADV_TT_CLIENT_NEW)) {
                batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags,
                                            message);
                goto out;
        }
        /* if this client has been added right now, it is possible to
         * immediately purge it
         */
        batadv_tt_local_event(bat_priv, tt_local_entry, BATADV_TT_CLIENT_DEL);

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

        /* extra call to free the local tt entry */
        batadv_tt_local_entry_put(tt_local_entry);

out:
        if (tt_local_entry)
                batadv_tt_local_entry_put(tt_local_entry);

        return curr_flags;
}

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

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

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

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

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

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

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

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

static void batadv_tt_local_table_free(struct batadv_priv *bat_priv)
{
        struct batadv_hashtable *hash;
        spinlock_t *list_lock; /* protects write access to the hash lists */
        struct batadv_tt_common_entry *tt_common_entry;
        struct batadv_tt_local_entry *tt_local;
        struct hlist_node *node_tmp;
        struct hlist_head *head;
        u32 i;

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

        hash = bat_priv->tt.local_hash;

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

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

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

        batadv_hash_destroy(hash);

        bat_priv->tt.local_hash = NULL;
}

static int batadv_tt_global_init(struct batadv_priv *bat_priv)
{
        if (bat_priv->tt.global_hash)
                return 0;

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

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

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

        return 0;
}

static void batadv_tt_changes_list_free(struct batadv_priv *bat_priv)
{
        struct batadv_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);
                kmem_cache_free(batadv_tt_change_cache, entry);
        }

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

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

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

                orig_entry = tmp_orig_entry;
                break;
        }
        rcu_read_unlock();

        return orig_entry;
}

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

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

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

                batadv_tt_orig_list_entry_put(orig_entry);
        }

        return found;
}

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

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

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

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

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

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

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

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

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

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

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

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

        /* if the node already has a local client for this entry, it has to wait
         * for a roaming advertisement instead of manually messing up the global
         * table
         */
        if ((flags & BATADV_TT_CLIENT_TEMP) && tt_local_entry &&
            !(tt_local_entry->common.flags & BATADV_TT_CLIENT_NEW))
                goto out;

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

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

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

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

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

                if (unlikely(hash_added != 0)) {
                        /* remove the reference for the hash */
                        batadv_tt_global_entry_put(tt_global_entry);
                        goto out_remove;
                }
        } else {
                common = &tt_global_entry->common;
                /* If there is already a global entry, we can use this one for
                 * our processing.
                 * But if we are trying to add a temporary client then here are
                 * two options at this point:
                 * 1) the global client is not a temporary client: the global
                 *    client has to be left as it is, temporary information
                 *    should never override any already known client state
                 * 2) the global client is a temporary client: purge the
                 *    originator list and add the new one orig_entry
                 */
                if (flags & BATADV_TT_CLIENT_TEMP) {
                        if (!(common->flags & BATADV_TT_CLIENT_TEMP))
                                goto out;
                        if (batadv_tt_global_entry_has_orig(tt_global_entry,
                                                            orig_node, NULL))
                                goto out_remove;
                        batadv_tt_global_del_orig_list(tt_global_entry);
                        goto add_orig_entry;
                }

                /* if the client was temporary added before receiving the first
                 * OGM announcing it, we have to clear the TEMP flag. Also,
                 * remove the previous temporary orig node and re-add it
                 * if required. If the orig entry changed, the new one which
                 * is a non-temporary entry is preferred.
                 */
                if (common->flags & BATADV_TT_CLIENT_TEMP) {
                        batadv_tt_global_del_orig_list(tt_global_entry);
                        common->flags &= ~BATADV_TT_CLIENT_TEMP;
                }

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

                /* If there is the BATADV_TT_CLIENT_ROAM flag set, there is only
                 * one originator left in the list and we previously received a
                 * delete + roaming change for this originator.
                 *
                 * We should first delete the old originator before adding the
                 * new one.
                 */
                if (common->flags & BATADV_TT_CLIENT_ROAM) {
                        batadv_tt_global_del_orig_list(tt_global_entry);
                        common->flags &= ~BATADV_TT_CLIENT_ROAM;
                        tt_global_entry->roam_at = 0;
                }
        }
add_orig_entry:
        /* add the new orig_entry (if needed) or update it */
        batadv_tt_global_orig_entry_add(tt_global_entry, orig_node, ttvn,
                                        flags & BATADV_TT_SYNC_MASK);

        batadv_dbg(BATADV_DBG_TT, bat_priv,
                   "Creating new global tt entry: %pM (vid: %d, via %pM)\n",
                   common->addr, batadv_print_vid(common->vid),
                   orig_node->orig);
        ret = true;

out_remove:
        /* Do not remove multicast addresses from the local hash on
         * global additions
         */
        if (is_multicast_ether_addr(tt_addr))
                goto out;

        /* remove address from local hash if present */
        local_flags = batadv_tt_local_remove(bat_priv, tt_addr, vid,
                                             "global tt received",
                                             flags & BATADV_TT_CLIENT_ROAM);
        tt_global_entry->common.flags |= local_flags & BATADV_TT_CLIENT_WIFI;

        if (!(flags & BATADV_TT_CLIENT_ROAM))
                /* this is a normal global add. Therefore the client is not in a
                 * roaming state anymore.
                 */
                tt_global_entry->common.flags &= ~BATADV_TT_CLIENT_ROAM;

out:
        if (tt_global_entry)
                batadv_tt_global_entry_put(tt_global_entry);
        if (tt_local_entry)
                batadv_tt_local_entry_put(tt_local_entry);
        return ret;
}

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

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

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

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

                best_entry = orig_entry;
                best_router = router;
        }

        if (best_router)
                batadv_neigh_node_put(best_router);

        return best_entry;
}

#ifdef CONFIG_BATMAN_ADV_DEBUGFS
/**
 * batadv_tt_global_print_entry() - print all orig nodes who announce the
 *  address for this global entry
 * @bat_priv: the bat priv with all the soft interface information
 * @tt_global_entry: global translation table entry to be printed
 * @seq: debugfs table seq_file struct
 *
 * This functon assumes the caller holds rcu_read_lock().
 */
static void
batadv_tt_global_print_entry(struct batadv_priv *bat_priv,
                             struct batadv_tt_global_entry *tt_global_entry,
                             struct seq_file *seq)
{
        struct batadv_tt_orig_list_entry *orig_entry, *best_entry;
        struct batadv_tt_common_entry *tt_common_entry;
        struct batadv_orig_node_vlan *vlan;
        struct hlist_head *head;
        u8 last_ttvn;
        u16 flags;

        tt_common_entry = &tt_global_entry->common;
        flags = tt_common_entry->flags;

        best_entry = batadv_transtable_best_orig(bat_priv, tt_global_entry);
        if (best_entry) {
                vlan = batadv_orig_node_vlan_get(best_entry->orig_node,
                                                 tt_common_entry->vid);
                if (!vlan) {
                        seq_printf(seq,
                                   " * Cannot retrieve VLAN %d for originator %pM\n",
                                   batadv_print_vid(tt_common_entry->vid),
                                   best_entry->orig_node->orig);
                        goto print_list;
                }

                last_ttvn = atomic_read(&best_entry->orig_node->last_ttvn);
                seq_printf(seq,
                           " %c %pM %4i   (%3u) via %pM     (%3u)   (%#.8x) [%c%c%c%c]\n",
                           '*', tt_global_entry->common.addr,
                           batadv_print_vid(tt_global_entry->common.vid),
                           best_entry->ttvn, best_entry->orig_node->orig,
                           last_ttvn, vlan->tt.crc,
                           ((flags & BATADV_TT_CLIENT_ROAM) ? 'R' : '.'),
                           ((flags & BATADV_TT_CLIENT_WIFI) ? 'W' : '.'),
                           ((flags & BATADV_TT_CLIENT_ISOLA) ? 'I' : '.'),
                           ((flags & BATADV_TT_CLIENT_TEMP) ? 'T' : '.'));

                batadv_orig_node_vlan_put(vlan);
        }

print_list:
        head = &tt_global_entry->orig_list;

        hlist_for_each_entry_rcu(orig_entry, head, list) {
                if (best_entry == orig_entry)
                        continue;

                vlan = batadv_orig_node_vlan_get(orig_entry->orig_node,
                                                 tt_common_entry->vid);
                if (!vlan) {
                        seq_printf(seq,
                                   " + Cannot retrieve VLAN %d for originator %pM\n",
                                   batadv_print_vid(tt_common_entry->vid),
                                   orig_entry->orig_node->orig);
                        continue;
                }

                last_ttvn = atomic_read(&orig_entry->orig_node->last_ttvn);
                seq_printf(seq,
                           " %c %pM %4d   (%3u) via %pM     (%3u)   (%#.8x) [%c%c%c%c]\n",
                           '+', tt_global_entry->common.addr,
                           batadv_print_vid(tt_global_entry->common.vid),
                           orig_entry->ttvn, orig_entry->orig_node->orig,
                           last_ttvn, vlan->tt.crc,
                           ((flags & BATADV_TT_CLIENT_ROAM) ? 'R' : '.'),
                           ((flags & BATADV_TT_CLIENT_WIFI) ? 'W' : '.'),
                           ((flags & BATADV_TT_CLIENT_ISOLA) ? 'I' : '.'),
                           ((flags & BATADV_TT_CLIENT_TEMP) ? 'T' : '.'));

                batadv_orig_node_vlan_put(vlan);
        }
}

/**
 * batadv_tt_global_seq_print_text() - Print the global tt table in a seq file
 * @seq: seq file to print on
 * @offset: not used
 *
 * Return: always 0
 */
int batadv_tt_global_seq_print_text(struct seq_file *seq, void *offset)
{
        struct net_device *net_dev = (struct net_device *)seq->private;
        struct batadv_priv *bat_priv = netdev_priv(net_dev);
        struct batadv_hashtable *hash = bat_priv->tt.global_hash;
        struct batadv_tt_common_entry *tt_common_entry;
        struct batadv_tt_global_entry *tt_global;
        struct batadv_hard_iface *primary_if;
        struct hlist_head *head;
        u32 i;

        primary_if = batadv_seq_print_text_primary_if_get(seq);
        if (!primary_if)
                goto out;

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

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

                rcu_read_lock();
                hlist_for_each_entry_rcu(tt_common_entry,
                                         head, hash_entry) {
                        tt_global = container_of(tt_common_entry,
                                                 struct batadv_tt_global_entry,
                                                 common);
                        batadv_tt_global_print_entry(bat_priv, tt_global, seq);
                }
                rcu_read_unlock();
        }
out:
        if (primary_if)
                batadv_hardif_put(primary_if);
        return 0;
}
#endif

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

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

        crc = vlan->tt.crc;

        batadv_orig_node_vlan_put(vlan);

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

        last_ttvn = atomic_read(&orig->orig_node->last_ttvn);

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

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

        genlmsg_end(msg, hdr);
        return 0;

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

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

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

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

                best = (orig_entry == best_entry);

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

        *sub_s = 0;
        return 0;
}

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

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

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

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

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

        ifindex = batadv_netlink_get_ifindex(cb->nlh, BATADV_ATTR_MESH_IFINDEX);
        if (!ifindex)
                return -EINVAL;

        soft_iface = dev_get_by_index(net, ifindex);
        if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
                ret = -ENODEV;
                goto out;
        }

        bat_priv = netdev_priv(soft_iface);

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

        hash = bat_priv->tt.global_hash;

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

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

                bucket++;
        }

        ret = msg->len;

 out:
        if (primary_if)
                batadv_hardif_put(primary_if);
        if (soft_iface)
                dev_put(soft_iface);

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

        return ret;
}

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

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

/* deletes the orig list of a tt_global_entry */
static void
batadv_tt_global_del_orig_list(struct batadv_tt_global_entry *tt_global_entry)
{
        struct hlist_head *head;
        struct hlist_node *safe;
        struct batadv_tt_orig_list_entry *orig_entry;

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

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

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

/* If the client is to be deleted, we check if it is the last origantor entry
 * within tt_global entry. If yes, we set the BATADV_TT_CLIENT_ROAM flag and the
 * timer, otherwise we simply remove the originator scheduled for deletion.
 */
static void
batadv_tt_global_del_roaming(struct batadv_priv *bat_priv,
                             struct batadv_tt_global_entry *tt_global_entry,
                             struct batadv_orig_node *orig_node,
                             const char *message)
{
        bool last_entry = true;
        struct hlist_head *head;
        struct batadv_tt_orig_list_entry *orig_entry;

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

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

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

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

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

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

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

                goto out;
        }

        /* if we are deleting a global entry due to a roam
         * event, there are two possibilities:
         * 1) the client roamed from node A to node B => if there
         *    is only one originator left for this client, we mark
         *    it with BATADV_TT_CLIENT_ROAM, we start a timer and we
         *    wait for node B to claim it. In case of timeout
         *    the entry is purged.
         *
         *    If there are other originators left, we directly delete
         *    the originator.
         * 2) the client roamed to us => we can directly delete
         *    the global entry, since it is useless now.
         */
        local_entry = batadv_tt_local_hash_find(bat_priv,
                                                tt_global_entry->common.addr,
                                                vid);
        if (local_entry) {
                /* local entry exists, case 2: client roamed to us. */
                batadv_tt_global_del_orig_list(tt_global_entry);
                batadv_tt_global_free(bat_priv, tt_global_entry, message);
        } else {
                /* no local entry exists, case 1: check for roaming */
                batadv_tt_global_del_roaming(bat_priv, tt_global_entry,
                                             orig_node, message);
        }

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

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

        if (!hash)
                return;

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

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

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

                        batadv_tt_global_del_orig_node(bat_priv, tt_global,
                                                       orig_node, message);

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

static bool batadv_tt_global_to_purge(struct batadv_tt_global_entry *tt_global,
                                      char **msg)
{
        bool purge = false;
        unsigned long roam_timeout = BATADV_TT_CLIENT_ROAM_TIMEOUT;
        unsigned long temp_timeout = BATADV_TT_CLIENT_TEMP_TIMEOUT;

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

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

        return purge;
}

static void batadv_tt_global_purge(struct batadv_priv *bat_priv)
{
        struct batadv_hashtable *hash = bat_priv->tt.global_hash;
        struct hlist_head *head;
        struct hlist_node *node_tmp;
        spinlock_t *list_lock; /* protects write access to the hash lists */
        u32 i;
        char *msg = NULL;
        struct batadv_tt_common_entry *tt_common;
        struct batadv_tt_global_entry *tt_global;

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

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

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

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

                        hlist_del_rcu(&tt_common->hash_entry);

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

static void batadv_tt_global_table_free(struct batadv_priv *bat_priv)
{
        struct batadv_hashtable *hash;
        spinlock_t *list_lock; /* protects write access to the hash lists */
        struct batadv_tt_common_entry *tt_common_entry;
        struct batadv_tt_global_entry *tt_global;
        struct hlist_node *node_tmp;
        struct hlist_head *head;
        u32 i;

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

        hash = bat_priv->tt.global_hash;

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

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

        batadv_hash_destroy(hash);

        bat_priv->tt.global_hash = NULL;
}

static bool
_batadv_is_ap_isolated(struct batadv_tt_local_entry *tt_local_entry,
                       struct batadv_tt_global_entry *tt_global_entry)
{
        if (tt_local_entry->common.flags & BATADV_TT_CLIENT_WIFI &&
            tt_global_entry->common.flags & BATADV_TT_CLIENT_WIFI)
                return true;

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

        return false;
}

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

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

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

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

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

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

        return orig_node;
}

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

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

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

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

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

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

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

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

                        batadv_tt_orig_list_entry_put(tt_orig);
                }
                rcu_read_unlock();
        }

        return crc;
}

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

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

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

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

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

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

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

        return crc;
}

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

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

        kmem_cache_free(batadv_tt_req_cache, tt_req_node);
}

/**
 * batadv_tt_req_node_put() - decrement the tt_req_node refcounter and
 *  possibly release it
 * @tt_req_node: tt_req_node to be free'd
 */
static void batadv_tt_req_node_put(struct batadv_tt_req_node *tt_req_node)
{
        kref_put(&tt_req_node->refcount, batadv_tt_req_node_release);
}

static void batadv_tt_req_list_free(struct batadv_priv *bat_priv)
{
        struct batadv_tt_req_node *node;
        struct hlist_node *safe;

        spin_lock_bh(&bat_priv->tt.req_list_lock);

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

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

static void batadv_tt_save_orig_buffer(struct batadv_priv *bat_priv,
                                       struct batadv_orig_node *orig_node,
                                       const void *tt_buff,
                                       u16 tt_buff_len)
{
        /* Replace the old buffer only if I received something in the
         * last OGM (the OGM could carry no changes)
         */
        spin_lock_bh(&orig_node->tt_buff_lock);
        if (tt_buff_len > 0) {
                kfree(orig_node->tt_buff);
                orig_node->tt_buff_len = 0;
                orig_node->tt_buff = kmalloc(tt_buff_len, GFP_ATOMIC);
                if (orig_node->tt_buff) {
                        memcpy(orig_node->tt_buff, tt_buff, tt_buff_len);
                        orig_node->tt_buff_len = tt_buff_len;
                }
        }
        spin_unlock_bh(&orig_node->tt_buff_lock);
}

static void batadv_tt_req_purge(struct batadv_priv *bat_priv)
{
        struct batadv_tt_req_node *node;
        struct hlist_node *safe;

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

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

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

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

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

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

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

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

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

        return true;
}

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

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

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

        return batadv_tt_global_entry_has_orig(tt_global_entry, orig_node,
                                               flags);
}

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

        tt_tot = batadv_tt_entries(tt_len);
        tt_change = (struct batadv_tvlv_tt_change *)tvlv_buff;

        if (!valid_cb)
                return;

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

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

                        ret = valid_cb(tt_common_entry, cb_data, &flags);

                        if (!ret)
                                continue;

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

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

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

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

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

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

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

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

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

        if (orig_num_vlan > num_vlan)
                return false;

        return true;
}

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

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

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

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

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

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

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

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

        size = sizeof(*tvlv_tt_data) + sizeof(*tt_vlan_req) * num_vlan;
        tvlv_tt_data = kzalloc(size, GFP_ATOMIC);
        if (!tvlv_tt_data)
                goto out;

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

        /* send all the CRCs within the request. This is needed by intermediate
         * nodes to ensure they have the correct table before replying
         */
        tt_vlan_req = (struct batadv_tvlv_tt_vlan_data *)(tvlv_tt_data + 1);
        for (i = 0; i < num_vlan; i++) {
                tt_vlan_req->vid = tt_vlan->vid;
                tt_vlan_req->crc = tt_vlan->crc;

                tt_vlan_req++;
                tt_vlan++;
        }

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

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

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

out:
        if (primary_if)
                batadv_hardif_put(primary_if);

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

        if (tt_req_node)
                batadv_tt_req_node_put(tt_req_node);

        kfree(tvlv_tt_data);
        return ret;
}

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

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

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

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

        orig_ttvn = (u8)atomic_read(&req_dst_orig_node->last_ttvn);
        req_ttvn = tt_data->ttvn;

        tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(tt_data + 1);
        /* this node doesn't have the requested data */
        if (orig_ttvn != req_ttvn ||
            !batadv_tt_global_check_crc(req_dst_orig_node, tt_vlan,
                                        ntohs(tt_data->num_vlan)))
                goto out;

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

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

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

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

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

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

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

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

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

        batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_TX);

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

        ret = true;
        goto out;

unlock:
        spin_unlock_bh(&req_dst_orig_node->tt_buff_lock);

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

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

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

        spin_lock_bh(&bat_priv->tt.commit_lock);

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

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

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

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

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

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

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

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

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

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

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

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

        batadv_inc_counter(bat_priv, BATADV_CNT_TT_RESPONSE_TX);

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

        goto out;

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

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

static void _batadv_tt_update_changes(struct batadv_priv *bat_priv,
                                      struct batadv_orig_node *orig_node,
                                      struct batadv_tvlv_tt_change *tt_change,
                                      u16 tt_num_changes, u8 ttvn)
{
        int i;
        int roams;

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

static void batadv_tt_fill_gtable(struct batadv_priv *bat_priv,
                                  struct batadv_tvlv_tt_change *tt_change,
                                  u8 ttvn, u8 *resp_src,
                                  u16 num_entries)
{
        struct batadv_orig_node *orig_node;

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

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

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

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

        atomic_set(&orig_node->last_ttvn, ttvn);

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

static void batadv_tt_update_changes(struct batadv_priv *bat_priv,
                                     struct batadv_orig_node *orig_node,
                                     u16 tt_num_changes, u8 ttvn,
                                     struct batadv_tvlv_tt_change *tt_change)
{
        _batadv_tt_update_changes(bat_priv, orig_node, tt_change,
                                  tt_num_changes, ttvn);

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

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

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

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

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

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

        spin_lock_bh(&orig_node->tt_lock);

        change_offset = sizeof(struct batadv_tvlv_tt_vlan_data);
        change_offset *= ntohs(tt_data->num_vlan);
        change_offset += sizeof(*tt_data);
        tvlv_ptr += change_offset;

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

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

        spin_unlock_bh(&orig_node->tt_lock);

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

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

static void batadv_tt_roam_list_free(struct batadv_priv *bat_priv)
{
        struct batadv_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);
                kmem_cache_free(batadv_tt_roam_cache, node);
        }

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

static void batadv_tt_roam_purge(struct batadv_priv *bat_priv)
{
        struct batadv_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 (!batadv_has_timed_out(node->first_time,
                                          BATADV_ROAMING_MAX_TIME))
                        continue;

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

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

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

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

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

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

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

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

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

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

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

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

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

        batadv_inc_counter(bat_priv, BATADV_CNT_TT_ROAM_ADV_TX);

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

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

out:
        if (primary_if)
                batadv_hardif_put(primary_if);
}

static void batadv_tt_purge(struct work_struct *work)
{
        struct delayed_work *delayed_work;
        struct batadv_priv_tt *priv_tt;
        struct batadv_priv *bat_priv;

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

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

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

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

        cancel_delayed_work_sync(&bat_priv->tt.work);

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

        kfree(bat_priv->tt.last_changeset);
}

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

        if (!hash)
                return;

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

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

                        if (!count)
                                continue;

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

/* Purge out all the tt local entries marked with BATADV_TT_CLIENT_PENDING */
static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv)
{
        struct batadv_hashtable *hash = bat_priv->tt.local_hash;
        struct batadv_tt_common_entry *tt_common;
        struct batadv_tt_local_entry *tt_local;
        struct hlist_node *node_tmp;
        struct hlist_head *head;
        spinlock_t *list_lock; /* protects write access to the hash lists */
        u32 i;

        if (!hash)
                return;

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

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

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

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

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

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

        if (atomic_read(&bat_priv->tt.local_changes) < 1) {
                if (!batadv_atomic_dec_not_zero(&bat_priv->tt.ogm_append_cnt))
                        batadv_tt_tvlv_container_update(bat_priv);
                return;
        }

        batadv_tt_local_set_flags(bat_priv, BATADV_TT_CLIENT_NEW, false, true);

        batadv_tt_local_purge_pending_clients(bat_priv);
        batadv_tt_local_update_crc(bat_priv);

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

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

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

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

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

        if (!atomic_read(&vlan->ap_isolation))
                goto vlan_put;

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

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

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

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

/**
 * batadv_tt_update_orig() - update global translation table with new tt
 *  information received via ogms
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: the orig_node of the ogm
 * @tt_buff: pointer to the first tvlv VLAN entry
 * @tt_num_vlan: number of tvlv VLAN entries
 * @tt_change: pointer to the first entry in the TT buffer
 * @tt_num_changes: number of tt changes inside the tt buffer
 * @ttvn: translation table version number of this changeset