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

#include "originator.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/container_of.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/gfp.h>
#include <linux/if_vlan.h>
#include <linux/jiffies.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/workqueue.h>
#include <uapi/linux/batadv_packet.h>

#include "distributed-arp-table.h"
#include "fragmentation.h"
#include "gateway_client.h"
#include "hard-interface.h"
#include "hash.h"
#include "log.h"
#include "multicast.h"
#include "netlink.h"
#include "routing.h"
#include "translation-table.h"

/* hash class keys */
static struct lock_class_key batadv_orig_hash_lock_class_key;

/**
 * batadv_orig_hash_find() - Find and return originator from orig_hash
 * @bat_priv: the bat priv with all the mesh interface information
 * @data: mac address of the originator
 *
 * Return: orig_node (with increased refcnt), NULL on errors
 */
struct batadv_orig_node *
batadv_orig_hash_find(struct batadv_priv *bat_priv, const void *data)
{
        struct batadv_hashtable *hash = bat_priv->orig_hash;
        struct hlist_head *head;
        struct batadv_orig_node *orig_node, *orig_node_tmp = NULL;
        int index;

        if (!hash)
                return NULL;

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

        rcu_read_lock();
        hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
                if (!batadv_compare_eth(orig_node, data))
                        continue;

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

                orig_node_tmp = orig_node;
                break;
        }
        rcu_read_unlock();

        return orig_node_tmp;
}

static void batadv_purge_orig(struct work_struct *work);

/**
 * batadv_compare_orig() - comparing function used in the originator hash table
 * @node: node in the local table
 * @data2: second object to compare the node to
 *
 * Return: true if they are the same originator
 */
bool batadv_compare_orig(const struct hlist_node *node, const void *data2)
{
        const void *data1 = container_of(node, struct batadv_orig_node,
                                         hash_entry);

        return batadv_compare_eth(data1, data2);
}

/**
 * batadv_orig_node_vlan_get() - get an orig_node_vlan object
 * @orig_node: the originator serving the VLAN
 * @vid: the VLAN identifier
 *
 * Return: the vlan object identified by vid and belonging to orig_node or NULL
 * if it does not exist.
 */
struct batadv_orig_node_vlan *
batadv_orig_node_vlan_get(struct batadv_orig_node *orig_node,
                          unsigned short vid)
{
        struct batadv_orig_node_vlan *vlan = NULL, *tmp;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp, &orig_node->vlan_list, list) {
                if (tmp->vid != vid)
                        continue;

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

                vlan = tmp;

                break;
        }
        rcu_read_unlock();

        return vlan;
}

/**
 * batadv_vlan_id_valid() - check if vlan id is in valid batman-adv encoding
 * @vid: the VLAN identifier
 *
 * Return: true when either no vlan is set or if VLAN is in correct range,
 *  false otherwise
 */
static bool batadv_vlan_id_valid(unsigned short vid)
{
        unsigned short non_vlan = vid & ~(BATADV_VLAN_HAS_TAG | VLAN_VID_MASK);

        if (vid == 0)
                return true;

        if (!(vid & BATADV_VLAN_HAS_TAG))
                return false;

        if (non_vlan)
                return false;

        return true;
}

/**
 * batadv_orig_node_vlan_new() - search and possibly create an orig_node_vlan
 *  object
 * @orig_node: the originator serving the VLAN
 * @vid: the VLAN identifier
 *
 * Return: NULL in case of failure or the vlan object identified by vid and
 * belonging to orig_node otherwise. The object is created and added to the list
 * if it does not exist.
 *
 * The object is returned with refcounter increased by 1.
 */
struct batadv_orig_node_vlan *
batadv_orig_node_vlan_new(struct batadv_orig_node *orig_node,
                          unsigned short vid)
{
        struct batadv_orig_node_vlan *vlan;

        if (!batadv_vlan_id_valid(vid))
                return NULL;

        spin_lock_bh(&orig_node->vlan_list_lock);

        /* first look if an object for this vid already exists */
        vlan = batadv_orig_node_vlan_get(orig_node, vid);
        if (vlan)
                goto out;

        vlan = kzalloc_obj(*vlan, GFP_ATOMIC);
        if (!vlan)
                goto out;

        kref_init(&vlan->refcount);
        vlan->vid = vid;

        kref_get(&vlan->refcount);
        hlist_add_head_rcu(&vlan->list, &orig_node->vlan_list);

out:
        spin_unlock_bh(&orig_node->vlan_list_lock);

        return vlan;
}

/**
 * batadv_orig_node_vlan_release() - release originator-vlan object from lists
 *  and queue for free after rcu grace period
 * @ref: kref pointer of the originator-vlan object
 */
void batadv_orig_node_vlan_release(struct kref *ref)
{
        struct batadv_orig_node_vlan *orig_vlan;

        orig_vlan = container_of(ref, struct batadv_orig_node_vlan, refcount);

        kfree_rcu(orig_vlan, rcu);
}

/**
 * batadv_originator_init() - Initialize all originator structures
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Return: 0 on success or negative error number in case of failure
 */
int batadv_originator_init(struct batadv_priv *bat_priv)
{
        if (bat_priv->orig_hash)
                return 0;

        bat_priv->orig_hash = batadv_hash_new(1024);

        if (!bat_priv->orig_hash)
                goto err;

        batadv_hash_set_lock_class(bat_priv->orig_hash,
                                   &batadv_orig_hash_lock_class_key);

        INIT_DELAYED_WORK(&bat_priv->orig_work, batadv_purge_orig);
        queue_delayed_work(batadv_event_workqueue,
                           &bat_priv->orig_work,
                           msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD));

        return 0;

err:
        return -ENOMEM;
}

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

        neigh_ifinfo = container_of(ref, struct batadv_neigh_ifinfo, refcount);

        if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
                batadv_hardif_put(neigh_ifinfo->if_outgoing);

        kfree_rcu(neigh_ifinfo, rcu);
}

/**
 * batadv_hardif_neigh_release() - release hardif neigh node from lists and
 *  queue for free after rcu grace period
 * @ref: kref pointer of the neigh_node
 */
void batadv_hardif_neigh_release(struct kref *ref)
{
        struct batadv_hardif_neigh_node *hardif_neigh;

        hardif_neigh = container_of(ref, struct batadv_hardif_neigh_node,
                                    refcount);

        spin_lock_bh(&hardif_neigh->if_incoming->neigh_list_lock);
        hlist_del_init_rcu(&hardif_neigh->list);
        spin_unlock_bh(&hardif_neigh->if_incoming->neigh_list_lock);

        batadv_hardif_put(hardif_neigh->if_incoming);
        kfree_rcu(hardif_neigh, rcu);
}

/**
 * batadv_neigh_node_release() - release neigh_node from lists and queue for
 *  free after rcu grace period
 * @ref: kref pointer of the neigh_node
 */
void batadv_neigh_node_release(struct kref *ref)
{
        struct hlist_node *node_tmp;
        struct batadv_neigh_node *neigh_node;
        struct batadv_neigh_ifinfo *neigh_ifinfo;

        neigh_node = container_of(ref, struct batadv_neigh_node, refcount);

        hlist_for_each_entry_safe(neigh_ifinfo, node_tmp,
                                  &neigh_node->ifinfo_list, list) {
                batadv_neigh_ifinfo_put(neigh_ifinfo);
        }

        batadv_hardif_neigh_put(neigh_node->hardif_neigh);

        batadv_hardif_put(neigh_node->if_incoming);

        kfree_rcu(neigh_node, rcu);
}

/**
 * batadv_orig_router_get() - router to the originator depending on iface
 * @orig_node: the orig node for the router
 * @if_outgoing: the interface where the payload packet has been received or
 *  the OGM should be sent to
 *
 * Return: the neighbor which should be the router for this orig_node/iface.
 *
 * The object is returned with refcounter increased by 1.
 */
struct batadv_neigh_node *
batadv_orig_router_get(struct batadv_orig_node *orig_node,
                       const struct batadv_hard_iface *if_outgoing)
{
        struct batadv_orig_ifinfo *orig_ifinfo;
        struct batadv_neigh_node *router = NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(orig_ifinfo, &orig_node->ifinfo_list, list) {
                if (orig_ifinfo->if_outgoing != if_outgoing)
                        continue;

                router = rcu_dereference(orig_ifinfo->router);
                break;
        }

        if (router && !kref_get_unless_zero(&router->refcount))
                router = NULL;

        rcu_read_unlock();
        return router;
}

/**
 * batadv_orig_to_router() - get next hop neighbor to an orig address
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_addr: the originator MAC address to search the best next hop router for
 * @if_outgoing: the interface where the payload packet has been received or
 *  the OGM should be sent to
 *
 * Return: A neighbor node which is the best router towards the given originator
 * address.
 */
struct batadv_neigh_node *
batadv_orig_to_router(struct batadv_priv *bat_priv, u8 *orig_addr,
                      struct batadv_hard_iface *if_outgoing)
{
        struct batadv_neigh_node *neigh_node;
        struct batadv_orig_node *orig_node;

        orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
        if (!orig_node)
                return NULL;

        neigh_node = batadv_find_router(bat_priv, orig_node, if_outgoing);
        batadv_orig_node_put(orig_node);

        return neigh_node;
}

/**
 * batadv_orig_ifinfo_get() - find the ifinfo from an orig_node
 * @orig_node: the orig node to be queried
 * @if_outgoing: the interface for which the ifinfo should be acquired
 *
 * Return: the requested orig_ifinfo or NULL if not found.
 *
 * The object is returned with refcounter increased by 1.
 */
struct batadv_orig_ifinfo *
batadv_orig_ifinfo_get(struct batadv_orig_node *orig_node,
                       struct batadv_hard_iface *if_outgoing)
{
        struct batadv_orig_ifinfo *tmp, *orig_ifinfo = NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp, &orig_node->ifinfo_list,
                                 list) {
                if (tmp->if_outgoing != if_outgoing)
                        continue;

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

                orig_ifinfo = tmp;
                break;
        }
        rcu_read_unlock();

        return orig_ifinfo;
}

/**
 * batadv_orig_ifinfo_new() - search and possibly create an orig_ifinfo object
 * @orig_node: the orig node to be queried
 * @if_outgoing: the interface for which the ifinfo should be acquired
 *
 * Return: NULL in case of failure or the orig_ifinfo object for the if_outgoing
 * interface otherwise. The object is created and added to the list
 * if it does not exist.
 *
 * The object is returned with refcounter increased by 1.
 */
struct batadv_orig_ifinfo *
batadv_orig_ifinfo_new(struct batadv_orig_node *orig_node,
                       struct batadv_hard_iface *if_outgoing)
{
        struct batadv_orig_ifinfo *orig_ifinfo;
        unsigned long reset_time;

        spin_lock_bh(&orig_node->neigh_list_lock);

        orig_ifinfo = batadv_orig_ifinfo_get(orig_node, if_outgoing);
        if (orig_ifinfo)
                goto out;

        orig_ifinfo = kzalloc_obj(*orig_ifinfo, GFP_ATOMIC);
        if (!orig_ifinfo)
                goto out;

        if (if_outgoing != BATADV_IF_DEFAULT)
                kref_get(&if_outgoing->refcount);

        reset_time = jiffies - 1;
        reset_time -= msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
        orig_ifinfo->batman_seqno_reset = reset_time;
        orig_ifinfo->if_outgoing = if_outgoing;
        INIT_HLIST_NODE(&orig_ifinfo->list);
        kref_init(&orig_ifinfo->refcount);

        kref_get(&orig_ifinfo->refcount);
        hlist_add_head_rcu(&orig_ifinfo->list,
                           &orig_node->ifinfo_list);
out:
        spin_unlock_bh(&orig_node->neigh_list_lock);
        return orig_ifinfo;
}

/**
 * batadv_neigh_ifinfo_get() - find the ifinfo from an neigh_node
 * @neigh: the neigh node to be queried
 * @if_outgoing: the interface for which the ifinfo should be acquired
 *
 * The object is returned with refcounter increased by 1.
 *
 * Return: the requested neigh_ifinfo or NULL if not found
 */
struct batadv_neigh_ifinfo *
batadv_neigh_ifinfo_get(struct batadv_neigh_node *neigh,
                        struct batadv_hard_iface *if_outgoing)
{
        struct batadv_neigh_ifinfo *neigh_ifinfo = NULL,
                                   *tmp_neigh_ifinfo;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_ifinfo, &neigh->ifinfo_list,
                                 list) {
                if (tmp_neigh_ifinfo->if_outgoing != if_outgoing)
                        continue;

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

                neigh_ifinfo = tmp_neigh_ifinfo;
                break;
        }
        rcu_read_unlock();

        return neigh_ifinfo;
}

/**
 * batadv_neigh_ifinfo_new() - search and possibly create an neigh_ifinfo object
 * @neigh: the neigh node to be queried
 * @if_outgoing: the interface for which the ifinfo should be acquired
 *
 * Return: NULL in case of failure or the neigh_ifinfo object for the
 * if_outgoing interface otherwise. The object is created and added to the list
 * if it does not exist.
 *
 * The object is returned with refcounter increased by 1.
 */
struct batadv_neigh_ifinfo *
batadv_neigh_ifinfo_new(struct batadv_neigh_node *neigh,
                        struct batadv_hard_iface *if_outgoing)
{
        struct batadv_neigh_ifinfo *neigh_ifinfo;

        spin_lock_bh(&neigh->ifinfo_lock);

        neigh_ifinfo = batadv_neigh_ifinfo_get(neigh, if_outgoing);
        if (neigh_ifinfo)
                goto out;

        neigh_ifinfo = kzalloc_obj(*neigh_ifinfo, GFP_ATOMIC);
        if (!neigh_ifinfo)
                goto out;

        if (if_outgoing)
                kref_get(&if_outgoing->refcount);

        INIT_HLIST_NODE(&neigh_ifinfo->list);
        kref_init(&neigh_ifinfo->refcount);
        neigh_ifinfo->if_outgoing = if_outgoing;

        kref_get(&neigh_ifinfo->refcount);
        hlist_add_head_rcu(&neigh_ifinfo->list, &neigh->ifinfo_list);

out:
        spin_unlock_bh(&neigh->ifinfo_lock);

        return neigh_ifinfo;
}

/**
 * batadv_neigh_node_get() - retrieve a neighbour from the list
 * @orig_node: originator which the neighbour belongs to
 * @hard_iface: the interface where this neighbour is connected to
 * @addr: the address of the neighbour
 *
 * Looks for and possibly returns a neighbour belonging to this originator list
 * which is connected through the provided hard interface.
 *
 * Return: neighbor when found. Otherwise NULL
 */
static struct batadv_neigh_node *
batadv_neigh_node_get(const struct batadv_orig_node *orig_node,
                      const struct batadv_hard_iface *hard_iface,
                      const u8 *addr)
{
        struct batadv_neigh_node *tmp_neigh_node, *res = NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_node, &orig_node->neigh_list, list) {
                if (!batadv_compare_eth(tmp_neigh_node->addr, addr))
                        continue;

                if (tmp_neigh_node->if_incoming != hard_iface)
                        continue;

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

                res = tmp_neigh_node;
                break;
        }
        rcu_read_unlock();

        return res;
}

/**
 * batadv_hardif_neigh_create() - create a hardif neighbour node
 * @hard_iface: the interface this neighbour is connected to
 * @neigh_addr: the interface address of the neighbour to retrieve
 * @orig_node: originator object representing the neighbour
 *
 * Return: the hardif neighbour node if found or created or NULL otherwise.
 */
static struct batadv_hardif_neigh_node *
batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface,
                           const u8 *neigh_addr,
                           struct batadv_orig_node *orig_node)
{
        struct batadv_priv *bat_priv = netdev_priv(hard_iface->mesh_iface);
        struct batadv_hardif_neigh_node *hardif_neigh;

        spin_lock_bh(&hard_iface->neigh_list_lock);

        /* check if neighbor hasn't been added in the meantime */
        hardif_neigh = batadv_hardif_neigh_get(hard_iface, neigh_addr);
        if (hardif_neigh)
                goto out;

        hardif_neigh = kzalloc_obj(*hardif_neigh, GFP_ATOMIC);
        if (!hardif_neigh)
                goto out;

        kref_get(&hard_iface->refcount);
        INIT_HLIST_NODE(&hardif_neigh->list);
        ether_addr_copy(hardif_neigh->addr, neigh_addr);
        ether_addr_copy(hardif_neigh->orig, orig_node->orig);
        hardif_neigh->if_incoming = hard_iface;
        hardif_neigh->last_seen = jiffies;

        kref_init(&hardif_neigh->refcount);

        if (bat_priv->algo_ops->neigh.hardif_init)
                bat_priv->algo_ops->neigh.hardif_init(hardif_neigh);

        hlist_add_head_rcu(&hardif_neigh->list, &hard_iface->neigh_list);

out:
        spin_unlock_bh(&hard_iface->neigh_list_lock);
        return hardif_neigh;
}

/**
 * batadv_hardif_neigh_get_or_create() - retrieve or create a hardif neighbour
 *  node
 * @hard_iface: the interface this neighbour is connected to
 * @neigh_addr: the interface address of the neighbour to retrieve
 * @orig_node: originator object representing the neighbour
 *
 * Return: the hardif neighbour node if found or created or NULL otherwise.
 */
static struct batadv_hardif_neigh_node *
batadv_hardif_neigh_get_or_create(struct batadv_hard_iface *hard_iface,
                                  const u8 *neigh_addr,
                                  struct batadv_orig_node *orig_node)
{
        struct batadv_hardif_neigh_node *hardif_neigh;

        /* first check without locking to avoid the overhead */
        hardif_neigh = batadv_hardif_neigh_get(hard_iface, neigh_addr);
        if (hardif_neigh)
                return hardif_neigh;

        return batadv_hardif_neigh_create(hard_iface, neigh_addr, orig_node);
}

/**
 * batadv_hardif_neigh_get() - retrieve a hardif neighbour from the list
 * @hard_iface: the interface where this neighbour is connected to
 * @neigh_addr: the address of the neighbour
 *
 * Looks for and possibly returns a neighbour belonging to this hard interface.
 *
 * Return: neighbor when found. Otherwise NULL
 */
struct batadv_hardif_neigh_node *
batadv_hardif_neigh_get(const struct batadv_hard_iface *hard_iface,
                        const u8 *neigh_addr)
{
        struct batadv_hardif_neigh_node *tmp_hardif_neigh, *hardif_neigh = NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_hardif_neigh,
                                 &hard_iface->neigh_list, list) {
                if (!batadv_compare_eth(tmp_hardif_neigh->addr, neigh_addr))
                        continue;

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

                hardif_neigh = tmp_hardif_neigh;
                break;
        }
        rcu_read_unlock();

        return hardif_neigh;
}

/**
 * batadv_neigh_node_create() - create a neigh node object
 * @orig_node: originator object representing the neighbour
 * @hard_iface: the interface where the neighbour is connected to
 * @neigh_addr: the mac address of the neighbour interface
 *
 * Allocates a new neigh_node object and initialises all the generic fields.
 *
 * Return: the neighbour node if found or created or NULL otherwise.
 */
static struct batadv_neigh_node *
batadv_neigh_node_create(struct batadv_orig_node *orig_node,
                         struct batadv_hard_iface *hard_iface,
                         const u8 *neigh_addr)
{
        struct batadv_neigh_node *neigh_node;
        struct batadv_hardif_neigh_node *hardif_neigh = NULL;

        spin_lock_bh(&orig_node->neigh_list_lock);

        neigh_node = batadv_neigh_node_get(orig_node, hard_iface, neigh_addr);
        if (neigh_node)
                goto out;

        hardif_neigh = batadv_hardif_neigh_get_or_create(hard_iface,
                                                         neigh_addr, orig_node);
        if (!hardif_neigh)
                goto out;

        neigh_node = kzalloc_obj(*neigh_node, GFP_ATOMIC);
        if (!neigh_node)
                goto out;

        INIT_HLIST_NODE(&neigh_node->list);
        INIT_HLIST_HEAD(&neigh_node->ifinfo_list);
        spin_lock_init(&neigh_node->ifinfo_lock);

        kref_get(&hard_iface->refcount);
        ether_addr_copy(neigh_node->addr, neigh_addr);
        neigh_node->if_incoming = hard_iface;
        neigh_node->orig_node = orig_node;
        neigh_node->last_seen = jiffies;

        /* increment unique neighbor refcount */
        kref_get(&hardif_neigh->refcount);
        neigh_node->hardif_neigh = hardif_neigh;

        /* extra reference for return */
        kref_init(&neigh_node->refcount);

        kref_get(&neigh_node->refcount);
        hlist_add_head_rcu(&neigh_node->list, &orig_node->neigh_list);

        batadv_dbg(BATADV_DBG_BATMAN, orig_node->bat_priv,
                   "Creating new neighbor %pM for orig_node %pM on interface %s\n",
                   neigh_addr, orig_node->orig, hard_iface->net_dev->name);

out:
        spin_unlock_bh(&orig_node->neigh_list_lock);

        batadv_hardif_neigh_put(hardif_neigh);
        return neigh_node;
}

/**
 * batadv_neigh_node_get_or_create() - retrieve or create a neigh node object
 * @orig_node: originator object representing the neighbour
 * @hard_iface: the interface where the neighbour is connected to
 * @neigh_addr: the mac address of the neighbour interface
 *
 * Return: the neighbour node if found or created or NULL otherwise.
 */
struct batadv_neigh_node *
batadv_neigh_node_get_or_create(struct batadv_orig_node *orig_node,
                                struct batadv_hard_iface *hard_iface,
                                const u8 *neigh_addr)
{
        struct batadv_neigh_node *neigh_node;

        /* first check without locking to avoid the overhead */
        neigh_node = batadv_neigh_node_get(orig_node, hard_iface, neigh_addr);
        if (neigh_node)
                return neigh_node;

        return batadv_neigh_node_create(orig_node, hard_iface, neigh_addr);
}

/**
 * batadv_hardif_neigh_dump() - Dump to netlink the neighbor infos for a
 *  specific outgoing interface
 * @msg: message to dump into
 * @cb: parameters for the dump
 *
 * Return: 0 or error value
 */
int batadv_hardif_neigh_dump(struct sk_buff *msg, struct netlink_callback *cb)
{
        struct batadv_hard_iface *primary_if, *hard_iface;
        struct net_device *mesh_iface;
        struct batadv_priv *bat_priv;
        int ret;

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

        bat_priv = netdev_priv(mesh_iface);

        primary_if = batadv_primary_if_get_selected(bat_priv);
        if (!primary_if) {
                ret = -ENOENT;
                goto out_put_mesh_iface;
        }

        if (primary_if->if_status != BATADV_IF_ACTIVE) {
                ret = -ENOENT;
                goto out_put_primary_if;
        }

        hard_iface = batadv_netlink_get_hardif(bat_priv, cb);
        if (IS_ERR(hard_iface) && PTR_ERR(hard_iface) != -ENONET) {
                ret = PTR_ERR(hard_iface);
                goto out_put_primary_if;
        } else if (IS_ERR(hard_iface)) {
                /* => PTR_ERR(hard_iface) == -ENONET
                 * => no hard-iface given, ok
                 */
                hard_iface = BATADV_IF_DEFAULT;
        }

        if (!bat_priv->algo_ops->neigh.dump) {
                ret = -EOPNOTSUPP;
                goto out_put_hard_iface;
        }

        bat_priv->algo_ops->neigh.dump(msg, cb, bat_priv, hard_iface);

        ret = msg->len;

out_put_hard_iface:
        batadv_hardif_put(hard_iface);
out_put_primary_if:
        batadv_hardif_put(primary_if);
out_put_mesh_iface:
        dev_put(mesh_iface);

        return ret;
}

/**
 * batadv_orig_ifinfo_release() - release orig_ifinfo from lists and queue for
 *  free after rcu grace period
 * @ref: kref pointer of the orig_ifinfo
 */
void batadv_orig_ifinfo_release(struct kref *ref)
{
        struct batadv_orig_ifinfo *orig_ifinfo;
        struct batadv_neigh_node *router;

        orig_ifinfo = container_of(ref, struct batadv_orig_ifinfo, refcount);

        if (orig_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
                batadv_hardif_put(orig_ifinfo->if_outgoing);

        /* this is the last reference to this object */
        router = rcu_dereference_protected(orig_ifinfo->router, true);
        batadv_neigh_node_put(router);

        kfree_rcu(orig_ifinfo, rcu);
}

/**
 * batadv_orig_node_free_rcu() - free the orig_node
 * @rcu: rcu pointer of the orig_node
 */
static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
{
        struct batadv_orig_node *orig_node;

        orig_node = container_of(rcu, struct batadv_orig_node, rcu);

        batadv_mcast_purge_orig(orig_node);

        batadv_frag_purge_orig(orig_node, NULL);

        kfree(orig_node->tt_buff);
        kfree(orig_node);
}

/**
 * batadv_orig_node_release() - release orig_node from lists and queue for
 *  free after rcu grace period
 * @ref: kref pointer of the orig_node
 */
void batadv_orig_node_release(struct kref *ref)
{
        struct hlist_node *node_tmp;
        struct batadv_neigh_node *neigh_node;
        struct batadv_orig_node *orig_node;
        struct batadv_orig_ifinfo *orig_ifinfo;
        struct batadv_orig_node_vlan *vlan;
        struct batadv_orig_ifinfo *last_candidate;

        orig_node = container_of(ref, struct batadv_orig_node, refcount);

        spin_lock_bh(&orig_node->neigh_list_lock);

        /* for all neighbors towards this originator ... */
        hlist_for_each_entry_safe(neigh_node, node_tmp,
                                  &orig_node->neigh_list, list) {
                hlist_del_rcu(&neigh_node->list);
                batadv_neigh_node_put(neigh_node);
        }

        hlist_for_each_entry_safe(orig_ifinfo, node_tmp,
                                  &orig_node->ifinfo_list, list) {
                hlist_del_rcu(&orig_ifinfo->list);
                batadv_orig_ifinfo_put(orig_ifinfo);
        }

        last_candidate = orig_node->last_bonding_candidate;
        orig_node->last_bonding_candidate = NULL;
        spin_unlock_bh(&orig_node->neigh_list_lock);

        batadv_orig_ifinfo_put(last_candidate);

        spin_lock_bh(&orig_node->vlan_list_lock);
        hlist_for_each_entry_safe(vlan, node_tmp, &orig_node->vlan_list, list) {
                hlist_del_rcu(&vlan->list);
                batadv_orig_node_vlan_put(vlan);
        }
        spin_unlock_bh(&orig_node->vlan_list_lock);

        call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
}

/**
 * batadv_originator_free() - Free all originator structures
 * @bat_priv: the bat priv with all the mesh interface information
 */
void batadv_originator_free(struct batadv_priv *bat_priv)
{
        struct batadv_hashtable *hash = bat_priv->orig_hash;
        struct hlist_node *node_tmp;
        struct hlist_head *head;
        spinlock_t *list_lock; /* spinlock to protect write access */
        struct batadv_orig_node *orig_node;
        u32 i;

        if (!hash)
                return;

        cancel_delayed_work_sync(&bat_priv->orig_work);

        bat_priv->orig_hash = NULL;

        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(orig_node, node_tmp,
                                          head, hash_entry) {
                        hlist_del_rcu(&orig_node->hash_entry);
                        batadv_orig_node_put(orig_node);
                }
                spin_unlock_bh(list_lock);
        }

        batadv_hash_destroy(hash);
}

/**
 * batadv_orig_node_new() - creates a new orig_node
 * @bat_priv: the bat priv with all the mesh interface information
 * @addr: the mac address of the originator
 *
 * Creates a new originator object and initialises all the generic fields.
 * The new object is not added to the originator list.
 *
 * Return: the newly created object or NULL on failure.
 */
struct batadv_orig_node *batadv_orig_node_new(struct batadv_priv *bat_priv,
                                              const u8 *addr)
{
        struct batadv_orig_node *orig_node;
        struct batadv_orig_node_vlan *vlan;
        unsigned long reset_time;
        int i;

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "Creating new originator: %pM\n", addr);

        orig_node = kzalloc_obj(*orig_node, GFP_ATOMIC);
        if (!orig_node)
                return NULL;

        INIT_HLIST_HEAD(&orig_node->neigh_list);
        INIT_HLIST_HEAD(&orig_node->vlan_list);
        INIT_HLIST_HEAD(&orig_node->ifinfo_list);
        spin_lock_init(&orig_node->bcast_seqno_lock);
        spin_lock_init(&orig_node->neigh_list_lock);
        spin_lock_init(&orig_node->tt_buff_lock);
        spin_lock_init(&orig_node->tt_lock);
        spin_lock_init(&orig_node->vlan_list_lock);

        /* extra reference for return */
        kref_init(&orig_node->refcount);

        orig_node->bat_priv = bat_priv;
        ether_addr_copy(orig_node->orig, addr);
        batadv_dat_init_orig_node_addr(orig_node);
        atomic_set(&orig_node->last_ttvn, 0);
        orig_node->tt_buff = NULL;
        orig_node->tt_buff_len = 0;
        orig_node->last_seen = jiffies;
        reset_time = jiffies - 1 - msecs_to_jiffies(BATADV_RESET_PROTECTION_MS);
        orig_node->bcast_seqno_reset = reset_time;

#ifdef CONFIG_BATMAN_ADV_MCAST
        orig_node->mcast_flags = BATADV_MCAST_WANT_NO_RTR4;
        orig_node->mcast_flags |= BATADV_MCAST_WANT_NO_RTR6;
        orig_node->mcast_flags |= BATADV_MCAST_HAVE_MC_PTYPE_CAPA;
        INIT_HLIST_NODE(&orig_node->mcast_want_all_unsnoopables_node);
        INIT_HLIST_NODE(&orig_node->mcast_want_all_ipv4_node);
        INIT_HLIST_NODE(&orig_node->mcast_want_all_ipv6_node);
        spin_lock_init(&orig_node->mcast_handler_lock);
#endif

        /* create a vlan object for the "untagged" LAN */
        vlan = batadv_orig_node_vlan_new(orig_node, BATADV_NO_FLAGS);
        if (!vlan)
                goto free_orig_node;
        /* batadv_orig_node_vlan_new() increases the refcounter.
         * Immediately release vlan since it is not needed anymore in this
         * context
         */
        batadv_orig_node_vlan_put(vlan);

        for (i = 0; i < BATADV_FRAG_BUFFER_COUNT; i++) {
                INIT_HLIST_HEAD(&orig_node->fragments[i].fragment_list);
                spin_lock_init(&orig_node->fragments[i].lock);
                orig_node->fragments[i].size = 0;
        }

        return orig_node;
free_orig_node:
        kfree(orig_node);
        return NULL;
}

/**
 * batadv_purge_neigh_ifinfo() - purge obsolete ifinfo entries from neighbor
 * @bat_priv: the bat priv with all the mesh interface information
 * @neigh: orig node which is to be checked
 */
static void
batadv_purge_neigh_ifinfo(struct batadv_priv *bat_priv,
                          struct batadv_neigh_node *neigh)
{
        struct batadv_neigh_ifinfo *neigh_ifinfo;
        struct batadv_hard_iface *if_outgoing;
        struct hlist_node *node_tmp;

        spin_lock_bh(&neigh->ifinfo_lock);

        /* for all ifinfo objects for this neighinator */
        hlist_for_each_entry_safe(neigh_ifinfo, node_tmp,
                                  &neigh->ifinfo_list, list) {
                if_outgoing = neigh_ifinfo->if_outgoing;

                /* always keep the default interface */
                if (if_outgoing == BATADV_IF_DEFAULT)
                        continue;

                /* don't purge if the interface is not (going) down */
                if (if_outgoing->if_status != BATADV_IF_INACTIVE &&
                    if_outgoing->if_status != BATADV_IF_NOT_IN_USE &&
                    if_outgoing->if_status != BATADV_IF_TO_BE_REMOVED)
                        continue;

                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "neighbor/ifinfo purge: neighbor %pM, iface: %s\n",
                           neigh->addr, if_outgoing->net_dev->name);

                hlist_del_rcu(&neigh_ifinfo->list);
                batadv_neigh_ifinfo_put(neigh_ifinfo);
        }

        spin_unlock_bh(&neigh->ifinfo_lock);
}

/**
 * batadv_purge_orig_ifinfo() - purge obsolete ifinfo entries from originator
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: orig node which is to be checked
 *
 * Return: true if any ifinfo entry was purged, false otherwise.
 */
static bool
batadv_purge_orig_ifinfo(struct batadv_priv *bat_priv,
                         struct batadv_orig_node *orig_node)
{
        struct batadv_orig_ifinfo *orig_ifinfo;
        struct batadv_hard_iface *if_outgoing;
        struct hlist_node *node_tmp;
        bool ifinfo_purged = false;

        spin_lock_bh(&orig_node->neigh_list_lock);

        /* for all ifinfo objects for this originator */
        hlist_for_each_entry_safe(orig_ifinfo, node_tmp,
                                  &orig_node->ifinfo_list, list) {
                if_outgoing = orig_ifinfo->if_outgoing;

                /* always keep the default interface */
                if (if_outgoing == BATADV_IF_DEFAULT)
                        continue;

                /* don't purge if the interface is not (going) down */
                if (if_outgoing->if_status != BATADV_IF_INACTIVE &&
                    if_outgoing->if_status != BATADV_IF_NOT_IN_USE &&
                    if_outgoing->if_status != BATADV_IF_TO_BE_REMOVED)
                        continue;

                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "router/ifinfo purge: originator %pM, iface: %s\n",
                           orig_node->orig, if_outgoing->net_dev->name);

                ifinfo_purged = true;

                hlist_del_rcu(&orig_ifinfo->list);
                batadv_orig_ifinfo_put(orig_ifinfo);
                if (orig_node->last_bonding_candidate == orig_ifinfo) {
                        orig_node->last_bonding_candidate = NULL;
                        batadv_orig_ifinfo_put(orig_ifinfo);
                }
        }

        spin_unlock_bh(&orig_node->neigh_list_lock);

        return ifinfo_purged;
}

/**
 * batadv_purge_orig_neighbors() - purges neighbors from originator
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: orig node which is to be checked
 *
 * Return: true if any neighbor was purged, false otherwise
 */
static bool
batadv_purge_orig_neighbors(struct batadv_priv *bat_priv,
                            struct batadv_orig_node *orig_node)
{
        struct hlist_node *node_tmp;
        struct batadv_neigh_node *neigh_node;
        bool neigh_purged = false;
        unsigned long last_seen;
        struct batadv_hard_iface *if_incoming;

        spin_lock_bh(&orig_node->neigh_list_lock);

        /* for all neighbors towards this originator ... */
        hlist_for_each_entry_safe(neigh_node, node_tmp,
                                  &orig_node->neigh_list, list) {
                last_seen = neigh_node->last_seen;
                if_incoming = neigh_node->if_incoming;

                if (batadv_has_timed_out(last_seen, BATADV_PURGE_TIMEOUT) ||
                    if_incoming->if_status == BATADV_IF_INACTIVE ||
                    if_incoming->if_status == BATADV_IF_NOT_IN_USE ||
                    if_incoming->if_status == BATADV_IF_TO_BE_REMOVED) {
                        if (if_incoming->if_status == BATADV_IF_INACTIVE ||
                            if_incoming->if_status == BATADV_IF_NOT_IN_USE ||
                            if_incoming->if_status == BATADV_IF_TO_BE_REMOVED)
                                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                                           "neighbor purge: originator %pM, neighbor: %pM, iface: %s\n",
                                           orig_node->orig, neigh_node->addr,
                                           if_incoming->net_dev->name);
                        else
                                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                                           "neighbor timeout: originator %pM, neighbor: %pM, last_seen: %u\n",
                                           orig_node->orig, neigh_node->addr,
                                           jiffies_to_msecs(last_seen));

                        neigh_purged = true;

                        hlist_del_rcu(&neigh_node->list);
                        batadv_neigh_node_put(neigh_node);
                } else {
                        /* only necessary if not the whole neighbor is to be
                         * deleted, but some interface has been removed.
                         */
                        batadv_purge_neigh_ifinfo(bat_priv, neigh_node);
                }
        }

        spin_unlock_bh(&orig_node->neigh_list_lock);
        return neigh_purged;
}

/**
 * batadv_find_best_neighbor() - finds the best neighbor after purging
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: orig node which is to be checked
 * @if_outgoing: the interface for which the metric should be compared
 *
 * Return: the current best neighbor, with refcount increased.
 */
static struct batadv_neigh_node *
batadv_find_best_neighbor(struct batadv_priv *bat_priv,
                          struct batadv_orig_node *orig_node,
                          struct batadv_hard_iface *if_outgoing)
{
        struct batadv_neigh_node *best = NULL, *neigh;
        struct batadv_algo_ops *bao = bat_priv->algo_ops;

        rcu_read_lock();
        hlist_for_each_entry_rcu(neigh, &orig_node->neigh_list, list) {
                if (best && (bao->neigh.cmp(neigh, if_outgoing, best,
                                            if_outgoing) <= 0))
                        continue;

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

                batadv_neigh_node_put(best);

                best = neigh;
        }
        rcu_read_unlock();

        return best;
}

/**
 * batadv_purge_orig_node() - purges obsolete information from an orig_node
 * @bat_priv: the bat priv with all the mesh interface information
 * @orig_node: orig node which is to be checked
 *
 * This function checks if the orig_node or substructures of it have become
 * obsolete, and purges this information if that's the case.
 *
 * Return: true if the orig_node is to be removed, false otherwise.
 */
static bool batadv_purge_orig_node(struct batadv_priv *bat_priv,
                                   struct batadv_orig_node *orig_node)
{
        struct batadv_neigh_node *best_neigh_node;
        struct batadv_hard_iface *hard_iface;
        bool changed_ifinfo, changed_neigh;
        struct list_head *iter;

        if (batadv_has_timed_out(orig_node->last_seen,
                                 2 * BATADV_PURGE_TIMEOUT)) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Originator timeout: originator %pM, last_seen %u\n",
                           orig_node->orig,
                           jiffies_to_msecs(orig_node->last_seen));
                return true;
        }
        changed_ifinfo = batadv_purge_orig_ifinfo(bat_priv, orig_node);
        changed_neigh = batadv_purge_orig_neighbors(bat_priv, orig_node);

        if (!changed_ifinfo && !changed_neigh)
                return false;

        /* first for NULL ... */
        best_neigh_node = batadv_find_best_neighbor(bat_priv, orig_node,
                                                    BATADV_IF_DEFAULT);
        batadv_update_route(bat_priv, orig_node, BATADV_IF_DEFAULT,
                            best_neigh_node);
        batadv_neigh_node_put(best_neigh_node);

        /* ... then for all other interfaces. */
        rcu_read_lock();
        netdev_for_each_lower_private_rcu(bat_priv->mesh_iface, hard_iface, iter) {
                if (hard_iface->if_status != BATADV_IF_ACTIVE)
                        continue;

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

                best_neigh_node = batadv_find_best_neighbor(bat_priv,
                                                            orig_node,
                                                            hard_iface);
                batadv_update_route(bat_priv, orig_node, hard_iface,
                                    best_neigh_node);
                batadv_neigh_node_put(best_neigh_node);

                batadv_hardif_put(hard_iface);
        }
        rcu_read_unlock();

        return false;
}

/**
 * batadv_purge_orig_ref() - Purge all outdated originators
 * @bat_priv: the bat priv with all the mesh interface information
 */
void batadv_purge_orig_ref(struct batadv_priv *bat_priv)
{
        struct batadv_hashtable *hash = bat_priv->orig_hash;
        struct hlist_node *node_tmp;
        struct hlist_head *head;
        spinlock_t *list_lock; /* spinlock to protect write access */
        struct batadv_orig_node *orig_node;
        u32 i;

        if (!hash)
                return;

        /* for all origins... */
        for (i = 0; i < hash->size; i++) {
                head = &hash->table[i];
                if (hlist_empty(head))
                        continue;
                list_lock = &hash->list_locks[i];

                spin_lock_bh(list_lock);
                hlist_for_each_entry_safe(orig_node, node_tmp,
                                          head, hash_entry) {
                        if (batadv_purge_orig_node(bat_priv, orig_node)) {
                                batadv_gw_node_delete(bat_priv, orig_node);
                                hlist_del_rcu(&orig_node->hash_entry);
                                batadv_tt_global_del_orig(orig_node->bat_priv,
                                                          orig_node, -1,
                                                          "originator timed out");
                                batadv_orig_node_put(orig_node);
                                continue;
                        }

                        batadv_frag_purge_orig(orig_node,
                                               batadv_frag_check_entry);
                }
                spin_unlock_bh(list_lock);
        }

        batadv_gw_election(bat_priv);
}

static void batadv_purge_orig(struct work_struct *work)
{
        struct delayed_work *delayed_work;
        struct batadv_priv *bat_priv;

        delayed_work = to_delayed_work(work);
        bat_priv = container_of(delayed_work, struct batadv_priv, orig_work);
        batadv_purge_orig_ref(bat_priv);
        queue_delayed_work(batadv_event_workqueue,
                           &bat_priv->orig_work,
                           msecs_to_jiffies(BATADV_ORIG_WORK_PERIOD));
}

/**
 * batadv_orig_dump() - Dump to netlink the originator infos for a specific
 *  outgoing interface
 * @msg: message to dump into
 * @cb: parameters for the dump
 *
 * Return: 0 or error value
 */
int batadv_orig_dump(struct sk_buff *msg, struct netlink_callback *cb)
{
        struct batadv_hard_iface *primary_if, *hard_iface;
        struct net_device *mesh_iface;
        struct batadv_priv *bat_priv;
        int ret;

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

        bat_priv = netdev_priv(mesh_iface);

        primary_if = batadv_primary_if_get_selected(bat_priv);
        if (!primary_if) {
                ret = -ENOENT;
                goto out_put_mesh_iface;
        }

        if (primary_if->if_status != BATADV_IF_ACTIVE) {
                ret = -ENOENT;
                goto out_put_primary_if;
        }

        hard_iface = batadv_netlink_get_hardif(bat_priv, cb);
        if (IS_ERR(hard_iface) && PTR_ERR(hard_iface) != -ENONET) {
                ret = PTR_ERR(hard_iface);
                goto out_put_primary_if;
        } else if (IS_ERR(hard_iface)) {
                /* => PTR_ERR(hard_iface) == -ENONET
                 * => no hard-iface given, ok
                 */
                hard_iface = BATADV_IF_DEFAULT;
        }

        if (!bat_priv->algo_ops->orig.dump) {
                ret = -EOPNOTSUPP;
                goto out_put_hard_iface;
        }

        bat_priv->algo_ops->orig.dump(msg, cb, bat_priv, hard_iface);

        ret = msg->len;

out_put_hard_iface:
        batadv_hardif_put(hard_iface);
out_put_primary_if:
        batadv_hardif_put(primary_if);
out_put_mesh_iface:
        dev_put(mesh_iface);

        return ret;
}