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

#include "bat_iv_ogm.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/byteorder/generic.h>
#include <linux/cache.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/pkt_sched.h>
#include <linux/prandom.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/genetlink.h>
#include <net/netlink.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>

#include "bat_algo.h"
#include "bitarray.h"
#include "gateway_client.h"
#include "hard-interface.h"
#include "hash.h"
#include "log.h"
#include "netlink.h"
#include "network-coding.h"
#include "originator.h"
#include "routing.h"
#include "send.h"
#include "translation-table.h"
#include "tvlv.h"

static void batadv_iv_send_outstanding_bat_ogm_packet(struct work_struct *work);

/**
 * enum batadv_dup_status - duplicate status
 */
enum batadv_dup_status {
        /** @BATADV_NO_DUP: the packet is no duplicate */
        BATADV_NO_DUP = 0,

        /**
         * @BATADV_ORIG_DUP: OGM is a duplicate in the originator (but not for
         *  the neighbor)
         */
        BATADV_ORIG_DUP,

        /** @BATADV_NEIGH_DUP: OGM is a duplicate for the neighbor */
        BATADV_NEIGH_DUP,

        /**
         * @BATADV_PROTECTED: originator is currently protected (after reboot)
         */
        BATADV_PROTECTED,
};

/**
 * batadv_ring_buffer_set() - update the ring buffer with the given value
 * @lq_recv: pointer to the ring buffer
 * @lq_index: index to store the value at
 * @value: value to store in the ring buffer
 */
static void batadv_ring_buffer_set(u8 lq_recv[], u8 *lq_index, u8 value)
{
        lq_recv[*lq_index] = value;
        *lq_index = (*lq_index + 1) % BATADV_TQ_GLOBAL_WINDOW_SIZE;
}

/**
 * batadv_ring_buffer_avg() - compute the average of all non-zero values stored
 * in the given ring buffer
 * @lq_recv: pointer to the ring buffer
 *
 * Return: computed average value.
 */
static u8 batadv_ring_buffer_avg(const u8 lq_recv[])
{
        const u8 *ptr;
        u16 count = 0;
        u16 i = 0;
        u16 sum = 0;

        ptr = lq_recv;

        while (i < BATADV_TQ_GLOBAL_WINDOW_SIZE) {
                if (*ptr != 0) {
                        count++;
                        sum += *ptr;
                }

                i++;
                ptr++;
        }

        if (count == 0)
                return 0;

        return (u8)(sum / count);
}

/**
 * batadv_iv_ogm_orig_get() - retrieve or create (if does not exist) an
 *  originator
 * @bat_priv: the bat priv with all the soft interface information
 * @addr: mac address of the originator
 *
 * Return: the originator object corresponding to the passed mac address or NULL
 * on failure.
 * If the object does not exist, it is created and initialised.
 */
static struct batadv_orig_node *
batadv_iv_ogm_orig_get(struct batadv_priv *bat_priv, const u8 *addr)
{
        struct batadv_orig_node *orig_node;
        int hash_added;

        orig_node = batadv_orig_hash_find(bat_priv, addr);
        if (orig_node)
                return orig_node;

        orig_node = batadv_orig_node_new(bat_priv, addr);
        if (!orig_node)
                return NULL;

        spin_lock_init(&orig_node->bat_iv.ogm_cnt_lock);

        kref_get(&orig_node->refcount);
        hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
                                     batadv_choose_orig, orig_node,
                                     &orig_node->hash_entry);
        if (hash_added != 0)
                goto free_orig_node_hash;

        return orig_node;

free_orig_node_hash:
        /* reference for batadv_hash_add */
        batadv_orig_node_put(orig_node);
        /* reference from batadv_orig_node_new */
        batadv_orig_node_put(orig_node);

        return NULL;
}

static struct batadv_neigh_node *
batadv_iv_ogm_neigh_new(struct batadv_hard_iface *hard_iface,
                        const u8 *neigh_addr,
                        struct batadv_orig_node *orig_node,
                        struct batadv_orig_node *orig_neigh)
{
        struct batadv_neigh_node *neigh_node;

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

        neigh_node->orig_node = orig_neigh;

out:
        return neigh_node;
}

static int batadv_iv_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
{
        struct batadv_ogm_packet *batadv_ogm_packet;
        unsigned char *ogm_buff;
        u32 random_seqno;

        mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);

        /* randomize initial seqno to avoid collision */
        get_random_bytes(&random_seqno, sizeof(random_seqno));
        atomic_set(&hard_iface->bat_iv.ogm_seqno, random_seqno);

        hard_iface->bat_iv.ogm_buff_len = BATADV_OGM_HLEN;
        ogm_buff = kmalloc(hard_iface->bat_iv.ogm_buff_len, GFP_ATOMIC);
        if (!ogm_buff) {
                mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
                return -ENOMEM;
        }

        hard_iface->bat_iv.ogm_buff = ogm_buff;

        batadv_ogm_packet = (struct batadv_ogm_packet *)ogm_buff;
        batadv_ogm_packet->packet_type = BATADV_IV_OGM;
        batadv_ogm_packet->version = BATADV_COMPAT_VERSION;
        batadv_ogm_packet->ttl = 2;
        batadv_ogm_packet->flags = BATADV_NO_FLAGS;
        batadv_ogm_packet->reserved = 0;
        batadv_ogm_packet->tq = BATADV_TQ_MAX_VALUE;

        mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);

        return 0;
}

static void batadv_iv_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
{
        mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);

        kfree(hard_iface->bat_iv.ogm_buff);
        hard_iface->bat_iv.ogm_buff = NULL;

        mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
}

static void batadv_iv_ogm_iface_update_mac(struct batadv_hard_iface *hard_iface)
{
        struct batadv_ogm_packet *batadv_ogm_packet;
        void *ogm_buff;

        mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);

        ogm_buff = hard_iface->bat_iv.ogm_buff;
        if (!ogm_buff)
                goto unlock;

        batadv_ogm_packet = ogm_buff;
        ether_addr_copy(batadv_ogm_packet->orig,
                        hard_iface->net_dev->dev_addr);
        ether_addr_copy(batadv_ogm_packet->prev_sender,
                        hard_iface->net_dev->dev_addr);

unlock:
        mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
}

static void
batadv_iv_ogm_primary_iface_set(struct batadv_hard_iface *hard_iface)
{
        struct batadv_ogm_packet *batadv_ogm_packet;
        void *ogm_buff;

        mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);

        ogm_buff = hard_iface->bat_iv.ogm_buff;
        if (!ogm_buff)
                goto unlock;

        batadv_ogm_packet = ogm_buff;
        batadv_ogm_packet->ttl = BATADV_TTL;

unlock:
        mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
}

/* when do we schedule our own ogm to be sent */
static unsigned long
batadv_iv_ogm_emit_send_time(const struct batadv_priv *bat_priv)
{
        unsigned int msecs;

        msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
        msecs += prandom_u32_max(2 * BATADV_JITTER);

        return jiffies + msecs_to_jiffies(msecs);
}

/* when do we schedule a ogm packet to be sent */
static unsigned long batadv_iv_ogm_fwd_send_time(void)
{
        return jiffies + msecs_to_jiffies(prandom_u32_max(BATADV_JITTER / 2));
}

/* apply hop penalty for a normal link */
static u8 batadv_hop_penalty(u8 tq, const struct batadv_priv *bat_priv)
{
        int hop_penalty = atomic_read(&bat_priv->hop_penalty);
        int new_tq;

        new_tq = tq * (BATADV_TQ_MAX_VALUE - hop_penalty);
        new_tq /= BATADV_TQ_MAX_VALUE;

        return new_tq;
}

/**
 * batadv_iv_ogm_aggr_packet() - checks if there is another OGM attached
 * @buff_pos: current position in the skb
 * @packet_len: total length of the skb
 * @ogm_packet: potential OGM in buffer
 *
 * Return: true if there is enough space for another OGM, false otherwise.
 */
static bool
batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len,
                          const struct batadv_ogm_packet *ogm_packet)
{
        int next_buff_pos = 0;

        /* check if there is enough space for the header */
        next_buff_pos += buff_pos + sizeof(*ogm_packet);
        if (next_buff_pos > packet_len)
                return false;

        /* check if there is enough space for the optional TVLV */
        next_buff_pos += ntohs(ogm_packet->tvlv_len);

        return (next_buff_pos <= packet_len) &&
               (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
}

/* send a batman ogm to a given interface */
static void batadv_iv_ogm_send_to_if(struct batadv_forw_packet *forw_packet,
                                     struct batadv_hard_iface *hard_iface)
{
        struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
        const char *fwd_str;
        u8 packet_num;
        s16 buff_pos;
        struct batadv_ogm_packet *batadv_ogm_packet;
        struct sk_buff *skb;
        u8 *packet_pos;

        if (hard_iface->if_status != BATADV_IF_ACTIVE)
                return;

        packet_num = 0;
        buff_pos = 0;
        packet_pos = forw_packet->skb->data;
        batadv_ogm_packet = (struct batadv_ogm_packet *)packet_pos;

        /* adjust all flags and log packets */
        while (batadv_iv_ogm_aggr_packet(buff_pos, forw_packet->packet_len,
                                         batadv_ogm_packet)) {
                /* we might have aggregated direct link packets with an
                 * ordinary base packet
                 */
                if (forw_packet->direct_link_flags & BIT(packet_num) &&
                    forw_packet->if_incoming == hard_iface)
                        batadv_ogm_packet->flags |= BATADV_DIRECTLINK;
                else
                        batadv_ogm_packet->flags &= ~BATADV_DIRECTLINK;

                if (packet_num > 0 || !forw_packet->own)
                        fwd_str = "Forwarding";
                else
                        fwd_str = "Sending own";

                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "%s %spacket (originator %pM, seqno %u, TQ %d, TTL %d, IDF %s) on interface %s [%pM]\n",
                           fwd_str, (packet_num > 0 ? "aggregated " : ""),
                           batadv_ogm_packet->orig,
                           ntohl(batadv_ogm_packet->seqno),
                           batadv_ogm_packet->tq, batadv_ogm_packet->ttl,
                           ((batadv_ogm_packet->flags & BATADV_DIRECTLINK) ?
                            "on" : "off"),
                           hard_iface->net_dev->name,
                           hard_iface->net_dev->dev_addr);

                buff_pos += BATADV_OGM_HLEN;
                buff_pos += ntohs(batadv_ogm_packet->tvlv_len);
                packet_num++;
                packet_pos = forw_packet->skb->data + buff_pos;
                batadv_ogm_packet = (struct batadv_ogm_packet *)packet_pos;
        }

        /* create clone because function is called more than once */
        skb = skb_clone(forw_packet->skb, GFP_ATOMIC);
        if (skb) {
                batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
                batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
                                   skb->len + ETH_HLEN);
                batadv_send_broadcast_skb(skb, hard_iface);
        }
}

/* send a batman ogm packet */
static void batadv_iv_ogm_emit(struct batadv_forw_packet *forw_packet)
{
        struct net_device *soft_iface;

        if (!forw_packet->if_incoming) {
                pr_err("Error - can't forward packet: incoming iface not specified\n");
                return;
        }

        soft_iface = forw_packet->if_incoming->soft_iface;

        if (WARN_ON(!forw_packet->if_outgoing))
                return;

        if (forw_packet->if_outgoing->soft_iface != soft_iface) {
                pr_warn("%s: soft interface switch for queued OGM\n", __func__);
                return;
        }

        if (forw_packet->if_incoming->if_status != BATADV_IF_ACTIVE)
                return;

        /* only for one specific outgoing interface */
        batadv_iv_ogm_send_to_if(forw_packet, forw_packet->if_outgoing);
}

/**
 * batadv_iv_ogm_can_aggregate() - find out if an OGM can be aggregated on an
 *  existing forward packet
 * @new_bat_ogm_packet: OGM packet to be aggregated
 * @bat_priv: the bat priv with all the soft interface information
 * @packet_len: (total) length of the OGM
 * @send_time: timestamp (jiffies) when the packet is to be sent
 * @directlink: true if this is a direct link packet
 * @if_incoming: interface where the packet was received
 * @if_outgoing: interface for which the retransmission should be considered
 * @forw_packet: the forwarded packet which should be checked
 *
 * Return: true if new_packet can be aggregated with forw_packet
 */
static bool
batadv_iv_ogm_can_aggregate(const struct batadv_ogm_packet *new_bat_ogm_packet,
                            struct batadv_priv *bat_priv,
                            int packet_len, unsigned long send_time,
                            bool directlink,
                            const struct batadv_hard_iface *if_incoming,
                            const struct batadv_hard_iface *if_outgoing,
                            const struct batadv_forw_packet *forw_packet)
{
        struct batadv_ogm_packet *batadv_ogm_packet;
        int aggregated_bytes = forw_packet->packet_len + packet_len;
        struct batadv_hard_iface *primary_if = NULL;
        bool res = false;
        unsigned long aggregation_end_time;

        batadv_ogm_packet = (struct batadv_ogm_packet *)forw_packet->skb->data;
        aggregation_end_time = send_time;
        aggregation_end_time += msecs_to_jiffies(BATADV_MAX_AGGREGATION_MS);

        /* we can aggregate the current packet to this aggregated packet
         * if:
         *
         * - the send time is within our MAX_AGGREGATION_MS time
         * - the resulting packet won't be bigger than
         *   MAX_AGGREGATION_BYTES
         * otherwise aggregation is not possible
         */
        if (!time_before(send_time, forw_packet->send_time) ||
            !time_after_eq(aggregation_end_time, forw_packet->send_time))
                return false;

        if (aggregated_bytes > BATADV_MAX_AGGREGATION_BYTES)
                return false;

        /* packet is not leaving on the same interface. */
        if (forw_packet->if_outgoing != if_outgoing)
                return false;

        /* check aggregation compatibility
         * -> direct link packets are broadcasted on
         *    their interface only
         * -> aggregate packet if the current packet is
         *    a "global" packet as well as the base
         *    packet
         */
        primary_if = batadv_primary_if_get_selected(bat_priv);
        if (!primary_if)
                return false;

        /* packets without direct link flag and high TTL
         * are flooded through the net
         */
        if (!directlink &&
            !(batadv_ogm_packet->flags & BATADV_DIRECTLINK) &&
            batadv_ogm_packet->ttl != 1 &&

            /* own packets originating non-primary
             * interfaces leave only that interface
             */
            (!forw_packet->own ||
             forw_packet->if_incoming == primary_if)) {
                res = true;
                goto out;
        }

        /* if the incoming packet is sent via this one
         * interface only - we still can aggregate
         */
        if (directlink &&
            new_bat_ogm_packet->ttl == 1 &&
            forw_packet->if_incoming == if_incoming &&

            /* packets from direct neighbors or
             * own secondary interface packets
             * (= secondary interface packets in general)
             */
            (batadv_ogm_packet->flags & BATADV_DIRECTLINK ||
             (forw_packet->own &&
              forw_packet->if_incoming != primary_if))) {
                res = true;
                goto out;
        }

out:
        batadv_hardif_put(primary_if);
        return res;
}

/**
 * batadv_iv_ogm_aggregate_new() - create a new aggregated packet and add this
 *  packet to it.
 * @packet_buff: pointer to the OGM
 * @packet_len: (total) length of the OGM
 * @send_time: timestamp (jiffies) when the packet is to be sent
 * @direct_link: whether this OGM has direct link status
 * @if_incoming: interface where the packet was received
 * @if_outgoing: interface for which the retransmission should be considered
 * @own_packet: true if it is a self-generated ogm
 */
static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
                                        int packet_len, unsigned long send_time,
                                        bool direct_link,
                                        struct batadv_hard_iface *if_incoming,
                                        struct batadv_hard_iface *if_outgoing,
                                        int own_packet)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batadv_forw_packet *forw_packet_aggr;
        struct sk_buff *skb;
        unsigned char *skb_buff;
        unsigned int skb_size;
        atomic_t *queue_left = own_packet ? NULL : &bat_priv->batman_queue_left;

        if (atomic_read(&bat_priv->aggregated_ogms) &&
            packet_len < BATADV_MAX_AGGREGATION_BYTES)
                skb_size = BATADV_MAX_AGGREGATION_BYTES;
        else
                skb_size = packet_len;

        skb_size += ETH_HLEN;

        skb = netdev_alloc_skb_ip_align(NULL, skb_size);
        if (!skb)
                return;

        forw_packet_aggr = batadv_forw_packet_alloc(if_incoming, if_outgoing,
                                                    queue_left, bat_priv, skb);
        if (!forw_packet_aggr) {
                kfree_skb(skb);
                return;
        }

        forw_packet_aggr->skb->priority = TC_PRIO_CONTROL;
        skb_reserve(forw_packet_aggr->skb, ETH_HLEN);

        skb_buff = skb_put(forw_packet_aggr->skb, packet_len);
        forw_packet_aggr->packet_len = packet_len;
        memcpy(skb_buff, packet_buff, packet_len);

        forw_packet_aggr->own = own_packet;
        forw_packet_aggr->direct_link_flags = BATADV_NO_FLAGS;
        forw_packet_aggr->send_time = send_time;

        /* save packet direct link flag status */
        if (direct_link)
                forw_packet_aggr->direct_link_flags |= 1;

        INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
                          batadv_iv_send_outstanding_bat_ogm_packet);

        batadv_forw_packet_ogmv1_queue(bat_priv, forw_packet_aggr, send_time);
}

/* aggregate a new packet into the existing ogm packet */
static void batadv_iv_ogm_aggregate(struct batadv_forw_packet *forw_packet_aggr,
                                    const unsigned char *packet_buff,
                                    int packet_len, bool direct_link)
{
        unsigned long new_direct_link_flag;

        skb_put_data(forw_packet_aggr->skb, packet_buff, packet_len);
        forw_packet_aggr->packet_len += packet_len;
        forw_packet_aggr->num_packets++;

        /* save packet direct link flag status */
        if (direct_link) {
                new_direct_link_flag = BIT(forw_packet_aggr->num_packets);
                forw_packet_aggr->direct_link_flags |= new_direct_link_flag;
        }
}

/**
 * batadv_iv_ogm_queue_add() - queue up an OGM for transmission
 * @bat_priv: the bat priv with all the soft interface information
 * @packet_buff: pointer to the OGM
 * @packet_len: (total) length of the OGM
 * @if_incoming: interface where the packet was received
 * @if_outgoing: interface for which the retransmission should be considered
 * @own_packet: true if it is a self-generated ogm
 * @send_time: timestamp (jiffies) when the packet is to be sent
 */
static void batadv_iv_ogm_queue_add(struct batadv_priv *bat_priv,
                                    unsigned char *packet_buff,
                                    int packet_len,
                                    struct batadv_hard_iface *if_incoming,
                                    struct batadv_hard_iface *if_outgoing,
                                    int own_packet, unsigned long send_time)
{
        /* _aggr -> pointer to the packet we want to aggregate with
         * _pos -> pointer to the position in the queue
         */
        struct batadv_forw_packet *forw_packet_aggr = NULL;
        struct batadv_forw_packet *forw_packet_pos = NULL;
        struct batadv_ogm_packet *batadv_ogm_packet;
        bool direct_link;
        unsigned long max_aggregation_jiffies;

        batadv_ogm_packet = (struct batadv_ogm_packet *)packet_buff;
        direct_link = !!(batadv_ogm_packet->flags & BATADV_DIRECTLINK);
        max_aggregation_jiffies = msecs_to_jiffies(BATADV_MAX_AGGREGATION_MS);

        /* find position for the packet in the forward queue */
        spin_lock_bh(&bat_priv->forw_bat_list_lock);
        /* own packets are not to be aggregated */
        if (atomic_read(&bat_priv->aggregated_ogms) && !own_packet) {
                hlist_for_each_entry(forw_packet_pos,
                                     &bat_priv->forw_bat_list, list) {
                        if (batadv_iv_ogm_can_aggregate(batadv_ogm_packet,
                                                        bat_priv, packet_len,
                                                        send_time, direct_link,
                                                        if_incoming,
                                                        if_outgoing,
                                                        forw_packet_pos)) {
                                forw_packet_aggr = forw_packet_pos;
                                break;
                        }
                }
        }

        /* nothing to aggregate with - either aggregation disabled or no
         * suitable aggregation packet found
         */
        if (!forw_packet_aggr) {
                /* the following section can run without the lock */
                spin_unlock_bh(&bat_priv->forw_bat_list_lock);

                /* if we could not aggregate this packet with one of the others
                 * we hold it back for a while, so that it might be aggregated
                 * later on
                 */
                if (!own_packet && atomic_read(&bat_priv->aggregated_ogms))
                        send_time += max_aggregation_jiffies;

                batadv_iv_ogm_aggregate_new(packet_buff, packet_len,
                                            send_time, direct_link,
                                            if_incoming, if_outgoing,
                                            own_packet);
        } else {
                batadv_iv_ogm_aggregate(forw_packet_aggr, packet_buff,
                                        packet_len, direct_link);
                spin_unlock_bh(&bat_priv->forw_bat_list_lock);
        }
}

static void batadv_iv_ogm_forward(struct batadv_orig_node *orig_node,
                                  const struct ethhdr *ethhdr,
                                  struct batadv_ogm_packet *batadv_ogm_packet,
                                  bool is_single_hop_neigh,
                                  bool is_from_best_next_hop,
                                  struct batadv_hard_iface *if_incoming,
                                  struct batadv_hard_iface *if_outgoing)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        u16 tvlv_len;

        if (batadv_ogm_packet->ttl <= 1) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
                return;
        }

        if (!is_from_best_next_hop) {
                /* Mark the forwarded packet when it is not coming from our
                 * best next hop. We still need to forward the packet for our
                 * neighbor link quality detection to work in case the packet
                 * originated from a single hop neighbor. Otherwise we can
                 * simply drop the ogm.
                 */
                if (is_single_hop_neigh)
                        batadv_ogm_packet->flags |= BATADV_NOT_BEST_NEXT_HOP;
                else
                        return;
        }

        tvlv_len = ntohs(batadv_ogm_packet->tvlv_len);

        batadv_ogm_packet->ttl--;
        ether_addr_copy(batadv_ogm_packet->prev_sender, ethhdr->h_source);

        /* apply hop penalty */
        batadv_ogm_packet->tq = batadv_hop_penalty(batadv_ogm_packet->tq,
                                                   bat_priv);

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "Forwarding packet: tq: %i, ttl: %i\n",
                   batadv_ogm_packet->tq, batadv_ogm_packet->ttl);

        if (is_single_hop_neigh)
                batadv_ogm_packet->flags |= BATADV_DIRECTLINK;
        else
                batadv_ogm_packet->flags &= ~BATADV_DIRECTLINK;

        batadv_iv_ogm_queue_add(bat_priv, (unsigned char *)batadv_ogm_packet,
                                BATADV_OGM_HLEN + tvlv_len,
                                if_incoming, if_outgoing, 0,
                                batadv_iv_ogm_fwd_send_time());
}

/**
 * batadv_iv_ogm_slide_own_bcast_window() - bitshift own OGM broadcast windows
 *  for the given interface
 * @hard_iface: the interface for which the windows have to be shifted
 */
static void
batadv_iv_ogm_slide_own_bcast_window(struct batadv_hard_iface *hard_iface)
{
        struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
        struct batadv_hashtable *hash = bat_priv->orig_hash;
        struct hlist_head *head;
        struct batadv_orig_node *orig_node;
        struct batadv_orig_ifinfo *orig_ifinfo;
        unsigned long *word;
        u32 i;
        u8 *w;

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

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

                                spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);
                                word = orig_ifinfo->bat_iv.bcast_own;
                                batadv_bit_get_packet(bat_priv, word, 1, 0);
                                w = &orig_ifinfo->bat_iv.bcast_own_sum;
                                *w = bitmap_weight(word,
                                                   BATADV_TQ_LOCAL_WINDOW_SIZE);
                                spin_unlock_bh(&orig_node->bat_iv.ogm_cnt_lock);
                        }
                }
                rcu_read_unlock();
        }
}

/**
 * batadv_iv_ogm_schedule_buff() - schedule submission of hardif ogm buffer
 * @hard_iface: interface whose ogm buffer should be transmitted
 */
static void batadv_iv_ogm_schedule_buff(struct batadv_hard_iface *hard_iface)
{
        struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
        unsigned char **ogm_buff = &hard_iface->bat_iv.ogm_buff;
        struct batadv_ogm_packet *batadv_ogm_packet;
        struct batadv_hard_iface *primary_if, *tmp_hard_iface;
        int *ogm_buff_len = &hard_iface->bat_iv.ogm_buff_len;
        u32 seqno;
        u16 tvlv_len = 0;
        unsigned long send_time;

        lockdep_assert_held(&hard_iface->bat_iv.ogm_buff_mutex);

        /* interface already disabled by batadv_iv_ogm_iface_disable */
        if (!*ogm_buff)
                return;

        /* the interface gets activated here to avoid race conditions between
         * the moment of activating the interface in
         * hardif_activate_interface() where the originator mac is set and
         * outdated packets (especially uninitialized mac addresses) in the
         * packet queue
         */
        if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
                hard_iface->if_status = BATADV_IF_ACTIVE;

        primary_if = batadv_primary_if_get_selected(bat_priv);

        if (hard_iface == primary_if) {
                /* tt changes have to be committed before the tvlv data is
                 * appended as it may alter the tt tvlv container
                 */
                batadv_tt_local_commit_changes(bat_priv);
                tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, ogm_buff,
                                                            ogm_buff_len,
                                                            BATADV_OGM_HLEN);
        }

        batadv_ogm_packet = (struct batadv_ogm_packet *)(*ogm_buff);
        batadv_ogm_packet->tvlv_len = htons(tvlv_len);

        /* change sequence number to network order */
        seqno = (u32)atomic_read(&hard_iface->bat_iv.ogm_seqno);
        batadv_ogm_packet->seqno = htonl(seqno);
        atomic_inc(&hard_iface->bat_iv.ogm_seqno);

        batadv_iv_ogm_slide_own_bcast_window(hard_iface);

        send_time = batadv_iv_ogm_emit_send_time(bat_priv);

        if (hard_iface != primary_if) {
                /* OGMs from secondary interfaces are only scheduled on their
                 * respective interfaces.
                 */
                batadv_iv_ogm_queue_add(bat_priv, *ogm_buff, *ogm_buff_len,
                                        hard_iface, hard_iface, 1, send_time);
                goto out;
        }

        /* OGMs from primary interfaces are scheduled on all
         * interfaces.
         */
        rcu_read_lock();
        list_for_each_entry_rcu(tmp_hard_iface, &batadv_hardif_list, list) {
                if (tmp_hard_iface->soft_iface != hard_iface->soft_iface)
                        continue;

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

                batadv_iv_ogm_queue_add(bat_priv, *ogm_buff,
                                        *ogm_buff_len, hard_iface,
                                        tmp_hard_iface, 1, send_time);

                batadv_hardif_put(tmp_hard_iface);
        }
        rcu_read_unlock();

out:
        batadv_hardif_put(primary_if);
}

static void batadv_iv_ogm_schedule(struct batadv_hard_iface *hard_iface)
{
        if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
            hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
                return;

        mutex_lock(&hard_iface->bat_iv.ogm_buff_mutex);
        batadv_iv_ogm_schedule_buff(hard_iface);
        mutex_unlock(&hard_iface->bat_iv.ogm_buff_mutex);
}

/**
 * batadv_iv_orig_ifinfo_sum() - Get bcast_own sum for originator over interface
 * @orig_node: originator which reproadcasted the OGMs directly
 * @if_outgoing: interface which transmitted the original OGM and received the
 *  direct rebroadcast
 *
 * Return: Number of replied (rebroadcasted) OGMs which were transmitted by
 *  an originator and directly (without intermediate hop) received by a specific
 *  interface
 */
static u8 batadv_iv_orig_ifinfo_sum(struct batadv_orig_node *orig_node,
                                    struct batadv_hard_iface *if_outgoing)
{
        struct batadv_orig_ifinfo *orig_ifinfo;
        u8 sum;

        orig_ifinfo = batadv_orig_ifinfo_get(orig_node, if_outgoing);
        if (!orig_ifinfo)
                return 0;

        spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);
        sum = orig_ifinfo->bat_iv.bcast_own_sum;
        spin_unlock_bh(&orig_node->bat_iv.ogm_cnt_lock);

        batadv_orig_ifinfo_put(orig_ifinfo);

        return sum;
}

/**
 * batadv_iv_ogm_orig_update() - use OGM to update corresponding data in an
 *  originator
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: the orig node who originally emitted the ogm packet
 * @orig_ifinfo: ifinfo for the outgoing interface of the orig_node
 * @ethhdr: Ethernet header of the OGM
 * @batadv_ogm_packet: the ogm packet
 * @if_incoming: interface where the packet was received
 * @if_outgoing: interface for which the retransmission should be considered
 * @dup_status: the duplicate status of this ogm packet.
 */
static void
batadv_iv_ogm_orig_update(struct batadv_priv *bat_priv,
                          struct batadv_orig_node *orig_node,
                          struct batadv_orig_ifinfo *orig_ifinfo,
                          const struct ethhdr *ethhdr,
                          const struct batadv_ogm_packet *batadv_ogm_packet,
                          struct batadv_hard_iface *if_incoming,
                          struct batadv_hard_iface *if_outgoing,
                          enum batadv_dup_status dup_status)
{
        struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
        struct batadv_neigh_ifinfo *router_ifinfo = NULL;
        struct batadv_neigh_node *neigh_node = NULL;
        struct batadv_neigh_node *tmp_neigh_node = NULL;
        struct batadv_neigh_node *router = NULL;
        u8 sum_orig, sum_neigh;
        u8 *neigh_addr;
        u8 tq_avg;

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "%s(): Searching and updating originator entry of received packet\n",
                   __func__);

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_node,
                                 &orig_node->neigh_list, list) {
                neigh_addr = tmp_neigh_node->addr;
                if (batadv_compare_eth(neigh_addr, ethhdr->h_source) &&
                    tmp_neigh_node->if_incoming == if_incoming &&
                    kref_get_unless_zero(&tmp_neigh_node->refcount)) {
                        if (WARN(neigh_node, "too many matching neigh_nodes"))
                                batadv_neigh_node_put(neigh_node);
                        neigh_node = tmp_neigh_node;
                        continue;
                }

                if (dup_status != BATADV_NO_DUP)
                        continue;

                /* only update the entry for this outgoing interface */
                neigh_ifinfo = batadv_neigh_ifinfo_get(tmp_neigh_node,
                                                       if_outgoing);
                if (!neigh_ifinfo)
                        continue;

                spin_lock_bh(&tmp_neigh_node->ifinfo_lock);
                batadv_ring_buffer_set(neigh_ifinfo->bat_iv.tq_recv,
                                       &neigh_ifinfo->bat_iv.tq_index, 0);
                tq_avg = batadv_ring_buffer_avg(neigh_ifinfo->bat_iv.tq_recv);
                neigh_ifinfo->bat_iv.tq_avg = tq_avg;
                spin_unlock_bh(&tmp_neigh_node->ifinfo_lock);

                batadv_neigh_ifinfo_put(neigh_ifinfo);
                neigh_ifinfo = NULL;
        }

        if (!neigh_node) {
                struct batadv_orig_node *orig_tmp;

                orig_tmp = batadv_iv_ogm_orig_get(bat_priv, ethhdr->h_source);
                if (!orig_tmp)
                        goto unlock;

                neigh_node = batadv_iv_ogm_neigh_new(if_incoming,
                                                     ethhdr->h_source,
                                                     orig_node, orig_tmp);

                batadv_orig_node_put(orig_tmp);
                if (!neigh_node)
                        goto unlock;
        } else {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Updating existing last-hop neighbor of originator\n");
        }

        rcu_read_unlock();
        neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
        if (!neigh_ifinfo)
                goto out;

        neigh_node->last_seen = jiffies;

        spin_lock_bh(&neigh_node->ifinfo_lock);
        batadv_ring_buffer_set(neigh_ifinfo->bat_iv.tq_recv,
                               &neigh_ifinfo->bat_iv.tq_index,
                               batadv_ogm_packet->tq);
        tq_avg = batadv_ring_buffer_avg(neigh_ifinfo->bat_iv.tq_recv);

        neigh_ifinfo->bat_iv.tq_avg = tq_avg;
        spin_unlock_bh(&neigh_node->ifinfo_lock);

        if (dup_status == BATADV_NO_DUP) {
                orig_ifinfo->last_ttl = batadv_ogm_packet->ttl;
                neigh_ifinfo->last_ttl = batadv_ogm_packet->ttl;
        }

        /* if this neighbor already is our next hop there is nothing
         * to change
         */
        router = batadv_orig_router_get(orig_node, if_outgoing);
        if (router == neigh_node)
                goto out;

        if (router) {
                router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
                if (!router_ifinfo)
                        goto out;

                /* if this neighbor does not offer a better TQ we won't
                 * consider it
                 */
                if (router_ifinfo->bat_iv.tq_avg > neigh_ifinfo->bat_iv.tq_avg)
                        goto out;
        }

        /* if the TQ is the same and the link not more symmetric we
         * won't consider it either
         */
        if (router_ifinfo &&
            neigh_ifinfo->bat_iv.tq_avg == router_ifinfo->bat_iv.tq_avg) {
                sum_orig = batadv_iv_orig_ifinfo_sum(router->orig_node,
                                                     router->if_incoming);
                sum_neigh = batadv_iv_orig_ifinfo_sum(neigh_node->orig_node,
                                                      neigh_node->if_incoming);
                if (sum_orig >= sum_neigh)
                        goto out;
        }

        batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
        goto out;

unlock:
        rcu_read_unlock();
out:
        batadv_neigh_node_put(neigh_node);
        batadv_neigh_node_put(router);
        batadv_neigh_ifinfo_put(neigh_ifinfo);
        batadv_neigh_ifinfo_put(router_ifinfo);
}

/**
 * batadv_iv_ogm_calc_tq() - calculate tq for current received ogm packet
 * @orig_node: the orig node who originally emitted the ogm packet
 * @orig_neigh_node: the orig node struct of the neighbor who sent the packet
 * @batadv_ogm_packet: the ogm packet
 * @if_incoming: interface where the packet was received
 * @if_outgoing: interface for which the retransmission should be considered
 *
 * Return: true if the link can be considered bidirectional, false otherwise
 */
static bool batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node,
                                  struct batadv_orig_node *orig_neigh_node,
                                  struct batadv_ogm_packet *batadv_ogm_packet,
                                  struct batadv_hard_iface *if_incoming,
                                  struct batadv_hard_iface *if_outgoing)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batadv_neigh_node *neigh_node = NULL, *tmp_neigh_node;
        struct batadv_neigh_ifinfo *neigh_ifinfo;
        u8 total_count;
        u8 orig_eq_count, neigh_rq_count, neigh_rq_inv, tq_own;
        unsigned int tq_iface_hop_penalty = BATADV_TQ_MAX_VALUE;
        unsigned int neigh_rq_inv_cube, neigh_rq_max_cube;
        unsigned int tq_asym_penalty, inv_asym_penalty;
        unsigned int combined_tq;
        bool ret = false;

        /* find corresponding one hop neighbor */
        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_node,
                                 &orig_neigh_node->neigh_list, list) {
                if (!batadv_compare_eth(tmp_neigh_node->addr,
                                        orig_neigh_node->orig))
                        continue;

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

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

                neigh_node = tmp_neigh_node;
                break;
        }
        rcu_read_unlock();

        if (!neigh_node)
                neigh_node = batadv_iv_ogm_neigh_new(if_incoming,
                                                     orig_neigh_node->orig,
                                                     orig_neigh_node,
                                                     orig_neigh_node);

        if (!neigh_node)
                goto out;

        /* if orig_node is direct neighbor update neigh_node last_seen */
        if (orig_node == orig_neigh_node)
                neigh_node->last_seen = jiffies;

        orig_node->last_seen = jiffies;

        /* find packet count of corresponding one hop neighbor */
        orig_eq_count = batadv_iv_orig_ifinfo_sum(orig_neigh_node, if_incoming);
        neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
        if (neigh_ifinfo) {
                neigh_rq_count = neigh_ifinfo->bat_iv.real_packet_count;
                batadv_neigh_ifinfo_put(neigh_ifinfo);
        } else {
                neigh_rq_count = 0;
        }

        /* pay attention to not get a value bigger than 100 % */
        if (orig_eq_count > neigh_rq_count)
                total_count = neigh_rq_count;
        else
                total_count = orig_eq_count;

        /* if we have too few packets (too less data) we set tq_own to zero
         * if we receive too few packets it is not considered bidirectional
         */
        if (total_count < BATADV_TQ_LOCAL_BIDRECT_SEND_MINIMUM ||
            neigh_rq_count < BATADV_TQ_LOCAL_BIDRECT_RECV_MINIMUM)
                tq_own = 0;
        else
                /* neigh_node->real_packet_count is never zero as we
                 * only purge old information when getting new
                 * information
                 */
                tq_own = (BATADV_TQ_MAX_VALUE * total_count) /  neigh_rq_count;

        /* 1 - ((1-x) ** 3), normalized to TQ_MAX_VALUE this does
         * affect the nearly-symmetric links only a little, but
         * punishes asymmetric links more.  This will give a value
         * between 0 and TQ_MAX_VALUE
         */
        neigh_rq_inv = BATADV_TQ_LOCAL_WINDOW_SIZE - neigh_rq_count;
        neigh_rq_inv_cube = neigh_rq_inv * neigh_rq_inv * neigh_rq_inv;
        neigh_rq_max_cube = BATADV_TQ_LOCAL_WINDOW_SIZE *
                            BATADV_TQ_LOCAL_WINDOW_SIZE *
                            BATADV_TQ_LOCAL_WINDOW_SIZE;
        inv_asym_penalty = BATADV_TQ_MAX_VALUE * neigh_rq_inv_cube;
        inv_asym_penalty /= neigh_rq_max_cube;
        tq_asym_penalty = BATADV_TQ_MAX_VALUE - inv_asym_penalty;
        tq_iface_hop_penalty -= atomic_read(&if_incoming->hop_penalty);

        /* penalize if the OGM is forwarded on the same interface. WiFi
         * interfaces and other half duplex devices suffer from throughput
         * drops as they can't send and receive at the same time.
         */
        if (if_outgoing && if_incoming == if_outgoing &&
            batadv_is_wifi_hardif(if_outgoing))
                tq_iface_hop_penalty = batadv_hop_penalty(tq_iface_hop_penalty,
                                                          bat_priv);

        combined_tq = batadv_ogm_packet->tq *
                      tq_own *
                      tq_asym_penalty *
                      tq_iface_hop_penalty;
        combined_tq /= BATADV_TQ_MAX_VALUE *
                       BATADV_TQ_MAX_VALUE *
                       BATADV_TQ_MAX_VALUE;
        batadv_ogm_packet->tq = combined_tq;

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "bidirectional: orig = %pM neigh = %pM => own_bcast = %2i, real recv = %2i, local tq: %3i, asym_penalty: %3i, iface_hop_penalty: %3i, total tq: %3i, if_incoming = %s, if_outgoing = %s\n",
                   orig_node->orig, orig_neigh_node->orig, total_count,
                   neigh_rq_count, tq_own, tq_asym_penalty,
                   tq_iface_hop_penalty, batadv_ogm_packet->tq,
                   if_incoming->net_dev->name,
                   if_outgoing ? if_outgoing->net_dev->name : "DEFAULT");

        /* if link has the minimum required transmission quality
         * consider it bidirectional
         */
        if (batadv_ogm_packet->tq >= BATADV_TQ_TOTAL_BIDRECT_LIMIT)
                ret = true;

out:
        batadv_neigh_node_put(neigh_node);
        return ret;
}

/**
 * batadv_iv_ogm_update_seqnos() -  process a batman packet for all interfaces,
 *  adjust the sequence number and find out whether it is a duplicate
 * @ethhdr: ethernet header of the packet
 * @batadv_ogm_packet: OGM packet to be considered
 * @if_incoming: interface on which the OGM packet was received
 * @if_outgoing: interface for which the retransmission should be considered
 *
 * Return: duplicate status as enum batadv_dup_status
 */
static enum batadv_dup_status
batadv_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
                            const struct batadv_ogm_packet *batadv_ogm_packet,
                            const struct batadv_hard_iface *if_incoming,
                            struct batadv_hard_iface *if_outgoing)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batadv_orig_node *orig_node;
        struct batadv_orig_ifinfo *orig_ifinfo = NULL;
        struct batadv_neigh_node *neigh_node;
        struct batadv_neigh_ifinfo *neigh_ifinfo;
        bool is_dup;
        s32 seq_diff;
        bool need_update = false;
        int set_mark;
        enum batadv_dup_status ret = BATADV_NO_DUP;
        u32 seqno = ntohl(batadv_ogm_packet->seqno);
        u8 *neigh_addr;
        u8 packet_count;
        unsigned long *bitmap;

        orig_node = batadv_iv_ogm_orig_get(bat_priv, batadv_ogm_packet->orig);
        if (!orig_node)
                return BATADV_NO_DUP;

        orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
        if (WARN_ON(!orig_ifinfo)) {
                batadv_orig_node_put(orig_node);
                return 0;
        }

        spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);
        seq_diff = seqno - orig_ifinfo->last_real_seqno;

        /* signalize caller that the packet is to be dropped. */
        if (!hlist_empty(&orig_node->neigh_list) &&
            batadv_window_protected(bat_priv, seq_diff,
                                    BATADV_TQ_LOCAL_WINDOW_SIZE,
                                    &orig_ifinfo->batman_seqno_reset, NULL)) {
                ret = BATADV_PROTECTED;
                goto out;
        }

        rcu_read_lock();
        hlist_for_each_entry_rcu(neigh_node, &orig_node->neigh_list, list) {
                neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node,
                                                       if_outgoing);
                if (!neigh_ifinfo)
                        continue;

                neigh_addr = neigh_node->addr;
                is_dup = batadv_test_bit(neigh_ifinfo->bat_iv.real_bits,
                                         orig_ifinfo->last_real_seqno,
                                         seqno);

                if (batadv_compare_eth(neigh_addr, ethhdr->h_source) &&
                    neigh_node->if_incoming == if_incoming) {
                        set_mark = 1;
                        if (is_dup)
                                ret = BATADV_NEIGH_DUP;
                } else {
                        set_mark = 0;
                        if (is_dup && ret != BATADV_NEIGH_DUP)
                                ret = BATADV_ORIG_DUP;
                }

                /* if the window moved, set the update flag. */
                bitmap = neigh_ifinfo->bat_iv.real_bits;
                need_update |= batadv_bit_get_packet(bat_priv, bitmap,
                                                     seq_diff, set_mark);

                packet_count = bitmap_weight(bitmap,
                                             BATADV_TQ_LOCAL_WINDOW_SIZE);
                neigh_ifinfo->bat_iv.real_packet_count = packet_count;
                batadv_neigh_ifinfo_put(neigh_ifinfo);
        }
        rcu_read_unlock();

        if (need_update) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "%s updating last_seqno: old %u, new %u\n",
                           if_outgoing ? if_outgoing->net_dev->name : "DEFAULT",
                           orig_ifinfo->last_real_seqno, seqno);
                orig_ifinfo->last_real_seqno = seqno;
        }

out:
        spin_unlock_bh(&orig_node->bat_iv.ogm_cnt_lock);
        batadv_orig_node_put(orig_node);
        batadv_orig_ifinfo_put(orig_ifinfo);
        return ret;
}

/**
 * batadv_iv_ogm_process_per_outif() - process a batman iv OGM for an outgoing
 *  interface
 * @skb: the skb containing the OGM
 * @ogm_offset: offset from skb->data to start of ogm header
 * @orig_node: the (cached) orig node for the originator of this OGM
 * @if_incoming: the interface where this packet was received
 * @if_outgoing: the interface for which the packet should be considered
 */
static void
batadv_iv_ogm_process_per_outif(const struct sk_buff *skb, int ogm_offset,
                                struct batadv_orig_node *orig_node,
                                struct batadv_hard_iface *if_incoming,
                                struct batadv_hard_iface *if_outgoing)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batadv_hardif_neigh_node *hardif_neigh = NULL;
        struct batadv_neigh_node *router = NULL;
        struct batadv_neigh_node *router_router = NULL;
        struct batadv_orig_node *orig_neigh_node;
        struct batadv_orig_ifinfo *orig_ifinfo;
        struct batadv_neigh_node *orig_neigh_router = NULL;
        struct batadv_neigh_ifinfo *router_ifinfo = NULL;
        struct batadv_ogm_packet *ogm_packet;
        enum batadv_dup_status dup_status;
        bool is_from_best_next_hop = false;
        bool is_single_hop_neigh = false;
        bool sameseq, similar_ttl;
        struct sk_buff *skb_priv;
        struct ethhdr *ethhdr;
        u8 *prev_sender;
        bool is_bidirect;

        /* create a private copy of the skb, as some functions change tq value
         * and/or flags.
         */
        skb_priv = skb_copy(skb, GFP_ATOMIC);
        if (!skb_priv)
                return;

        ethhdr = eth_hdr(skb_priv);
        ogm_packet = (struct batadv_ogm_packet *)(skb_priv->data + ogm_offset);

        dup_status = batadv_iv_ogm_update_seqnos(ethhdr, ogm_packet,
                                                 if_incoming, if_outgoing);
        if (batadv_compare_eth(ethhdr->h_source, ogm_packet->orig))
                is_single_hop_neigh = true;

        if (dup_status == BATADV_PROTECTED) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: packet within seqno protection time (sender: %pM)\n",
                           ethhdr->h_source);
                goto out;
        }

        if (ogm_packet->tq == 0) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: originator packet with tq equal 0\n");
                goto out;
        }

        if (is_single_hop_neigh) {
                hardif_neigh = batadv_hardif_neigh_get(if_incoming,
                                                       ethhdr->h_source);
                if (hardif_neigh)
                        hardif_neigh->last_seen = jiffies;
        }

        router = batadv_orig_router_get(orig_node, if_outgoing);
        if (router) {
                router_router = batadv_orig_router_get(router->orig_node,
                                                       if_outgoing);
                router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
        }

        if ((router_ifinfo && router_ifinfo->bat_iv.tq_avg != 0) &&
            (batadv_compare_eth(router->addr, ethhdr->h_source)))
                is_from_best_next_hop = true;

        prev_sender = ogm_packet->prev_sender;
        /* avoid temporary routing loops */
        if (router && router_router &&
            (batadv_compare_eth(router->addr, prev_sender)) &&
            !(batadv_compare_eth(ogm_packet->orig, prev_sender)) &&
            (batadv_compare_eth(router->addr, router_router->addr))) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: ignoring all rebroadcast packets that may make me loop (sender: %pM)\n",
                           ethhdr->h_source);
                goto out;
        }

        if (if_outgoing == BATADV_IF_DEFAULT)
                batadv_tvlv_ogm_receive(bat_priv, ogm_packet, orig_node);

        /* if sender is a direct neighbor the sender mac equals
         * originator mac
         */
        if (is_single_hop_neigh)
                orig_neigh_node = orig_node;
        else
                orig_neigh_node = batadv_iv_ogm_orig_get(bat_priv,
                                                         ethhdr->h_source);

        if (!orig_neigh_node)
                goto out;

        /* Update nc_nodes of the originator */
        batadv_nc_update_nc_node(bat_priv, orig_node, orig_neigh_node,
                                 ogm_packet, is_single_hop_neigh);

        orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
                                                   if_outgoing);

        /* drop packet if sender is not a direct neighbor and if we
         * don't route towards it
         */
        if (!is_single_hop_neigh && !orig_neigh_router) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: OGM via unknown neighbor!\n");
                goto out_neigh;
        }

        is_bidirect = batadv_iv_ogm_calc_tq(orig_node, orig_neigh_node,
                                            ogm_packet, if_incoming,
                                            if_outgoing);

        /* update ranking if it is not a duplicate or has the same
         * seqno and similar ttl as the non-duplicate
         */
        orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
        if (!orig_ifinfo)
                goto out_neigh;

        sameseq = orig_ifinfo->last_real_seqno == ntohl(ogm_packet->seqno);
        similar_ttl = (orig_ifinfo->last_ttl - 3) <= ogm_packet->ttl;

        if (is_bidirect && (dup_status == BATADV_NO_DUP ||
                            (sameseq && similar_ttl))) {
                batadv_iv_ogm_orig_update(bat_priv, orig_node,
                                          orig_ifinfo, ethhdr,
                                          ogm_packet, if_incoming,
                                          if_outgoing, dup_status);
        }
        batadv_orig_ifinfo_put(orig_ifinfo);

        /* only forward for specific interface, not for the default one. */
        if (if_outgoing == BATADV_IF_DEFAULT)
                goto out_neigh;

        /* is single hop (direct) neighbor */
        if (is_single_hop_neigh) {
                /* OGMs from secondary interfaces should only scheduled once
                 * per interface where it has been received, not multiple times
                 */
                if (ogm_packet->ttl <= 2 &&
                    if_incoming != if_outgoing) {
                        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                                   "Drop packet: OGM from secondary interface and wrong outgoing interface\n");
                        goto out_neigh;
                }
                /* mark direct link on incoming interface */
                batadv_iv_ogm_forward(orig_node, ethhdr, ogm_packet,
                                      is_single_hop_neigh,
                                      is_from_best_next_hop, if_incoming,
                                      if_outgoing);

                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Forwarding packet: rebroadcast neighbor packet with direct link flag\n");
                goto out_neigh;
        }

        /* multihop originator */
        if (!is_bidirect) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: not received via bidirectional link\n");
                goto out_neigh;
        }

        if (dup_status == BATADV_NEIGH_DUP) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: duplicate packet received\n");
                goto out_neigh;
        }

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "Forwarding packet: rebroadcast originator packet\n");
        batadv_iv_ogm_forward(orig_node, ethhdr, ogm_packet,
                              is_single_hop_neigh, is_from_best_next_hop,
                              if_incoming, if_outgoing);

out_neigh:
        if (orig_neigh_node && !is_single_hop_neigh)
                batadv_orig_node_put(orig_neigh_node);
out:
        batadv_neigh_ifinfo_put(router_ifinfo);
        batadv_neigh_node_put(router);
        batadv_neigh_node_put(router_router);
        batadv_neigh_node_put(orig_neigh_router);
        batadv_hardif_neigh_put(hardif_neigh);

        consume_skb(skb_priv);
}

/**
 * batadv_iv_ogm_process_reply() - Check OGM for direct reply and process it
 * @ogm_packet: rebroadcast OGM packet to process
 * @if_incoming: the interface where this packet was received
 * @orig_node: originator which reproadcasted the OGMs
 * @if_incoming_seqno: OGM sequence number when rebroadcast was received
 */
static void batadv_iv_ogm_process_reply(struct batadv_ogm_packet *ogm_packet,
                                        struct batadv_hard_iface *if_incoming,
                                        struct batadv_orig_node *orig_node,
                                        u32 if_incoming_seqno)
{
        struct batadv_orig_ifinfo *orig_ifinfo;
        s32 bit_pos;
        u8 *weight;

        /* neighbor has to indicate direct link and it has to
         * come via the corresponding interface
         */
        if (!(ogm_packet->flags & BATADV_DIRECTLINK))
                return;

        if (!batadv_compare_eth(if_incoming->net_dev->dev_addr,
                                ogm_packet->orig))
                return;

        orig_ifinfo = batadv_orig_ifinfo_get(orig_node, if_incoming);
        if (!orig_ifinfo)
                return;

        /* save packet seqno for bidirectional check */
        spin_lock_bh(&orig_node->bat_iv.ogm_cnt_lock);
        bit_pos = if_incoming_seqno - 2;
        bit_pos -= ntohl(ogm_packet->seqno);
        batadv_set_bit(orig_ifinfo->bat_iv.bcast_own, bit_pos);
        weight = &orig_ifinfo->bat_iv.bcast_own_sum;
        *weight = bitmap_weight(orig_ifinfo->bat_iv.bcast_own,
                                BATADV_TQ_LOCAL_WINDOW_SIZE);
        spin_unlock_bh(&orig_node->bat_iv.ogm_cnt_lock);

        batadv_orig_ifinfo_put(orig_ifinfo);
}

/**
 * batadv_iv_ogm_process() - process an incoming batman iv OGM
 * @skb: the skb containing the OGM
 * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 * @if_incoming: the interface where this packet was received
 */
static void batadv_iv_ogm_process(const struct sk_buff *skb, int ogm_offset,
                                  struct batadv_hard_iface *if_incoming)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batadv_orig_node *orig_neigh_node, *orig_node;
        struct batadv_hard_iface *hard_iface;
        struct batadv_ogm_packet *ogm_packet;
        u32 if_incoming_seqno;
        bool has_directlink_flag;
        struct ethhdr *ethhdr;
        bool is_my_oldorig = false;
        bool is_my_addr = false;
        bool is_my_orig = false;

        ogm_packet = (struct batadv_ogm_packet *)(skb->data + ogm_offset);
        ethhdr = eth_hdr(skb);

        /* Silently drop when the batman packet is actually not a
         * correct packet.
         *
         * This might happen if a packet is padded (e.g. Ethernet has a
         * minimum frame length of 64 byte) and the aggregation interprets
         * it as an additional length.
         *
         * TODO: A more sane solution would be to have a bit in the
         * batadv_ogm_packet to detect whether the packet is the last
         * packet in an aggregation.  Here we expect that the padding
         * is always zero (or not 0x01)
         */
        if (ogm_packet->packet_type != BATADV_IV_OGM)
                return;

        /* could be changed by schedule_own_packet() */
        if_incoming_seqno = atomic_read(&if_incoming->bat_iv.ogm_seqno);

        if (ogm_packet->flags & BATADV_DIRECTLINK)
                has_directlink_flag = true;
        else
                has_directlink_flag = false;

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "Received BATMAN packet via NB: %pM, IF: %s [%pM] (from OG: %pM, via prev OG: %pM, seqno %u, tq %d, TTL %d, V %d, IDF %d)\n",
                   ethhdr->h_source, if_incoming->net_dev->name,
                   if_incoming->net_dev->dev_addr, ogm_packet->orig,
                   ogm_packet->prev_sender, ntohl(ogm_packet->seqno),
                   ogm_packet->tq, ogm_packet->ttl,
                   ogm_packet->version, has_directlink_flag);

        rcu_read_lock();
        list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
                if (hard_iface->if_status != BATADV_IF_ACTIVE)
                        continue;

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

                if (batadv_compare_eth(ethhdr->h_source,
                                       hard_iface->net_dev->dev_addr))
                        is_my_addr = true;

                if (batadv_compare_eth(ogm_packet->orig,
                                       hard_iface->net_dev->dev_addr))
                        is_my_orig = true;

                if (batadv_compare_eth(ogm_packet->prev_sender,
                                       hard_iface->net_dev->dev_addr))
                        is_my_oldorig = true;
        }
        rcu_read_unlock();

        if (is_my_addr) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: received my own broadcast (sender: %pM)\n",
                           ethhdr->h_source);
                return;
        }

        if (is_my_orig) {
                orig_neigh_node = batadv_iv_ogm_orig_get(bat_priv,
                                                         ethhdr->h_source);
                if (!orig_neigh_node)
                        return;

                batadv_iv_ogm_process_reply(ogm_packet, if_incoming,
                                            orig_neigh_node, if_incoming_seqno);

                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: originator packet from myself (via neighbor)\n");
                batadv_orig_node_put(orig_neigh_node);
                return;
        }

        if (is_my_oldorig) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: ignoring all rebroadcast echos (sender: %pM)\n",
                           ethhdr->h_source);
                return;
        }

        if (ogm_packet->flags & BATADV_NOT_BEST_NEXT_HOP) {
                batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                           "Drop packet: ignoring all packets not forwarded from the best next hop (sender: %pM)\n",
                           ethhdr->h_source);
                return;
        }

        orig_node = batadv_iv_ogm_orig_get(bat_priv, ogm_packet->orig);
        if (!orig_node)
                return;

        batadv_iv_ogm_process_per_outif(skb, ogm_offset, orig_node,
                                        if_incoming, BATADV_IF_DEFAULT);

        rcu_read_lock();
        list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
                if (hard_iface->if_status != BATADV_IF_ACTIVE)
                        continue;

                if (hard_iface->soft_iface != bat_priv->soft_iface)
                        continue;

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

                batadv_iv_ogm_process_per_outif(skb, ogm_offset, orig_node,
                                                if_incoming, hard_iface);

                batadv_hardif_put(hard_iface);
        }
        rcu_read_unlock();

        batadv_orig_node_put(orig_node);
}

static void batadv_iv_send_outstanding_bat_ogm_packet(struct work_struct *work)
{
        struct delayed_work *delayed_work;
        struct batadv_forw_packet *forw_packet;
        struct batadv_priv *bat_priv;
        bool dropped = false;

        delayed_work = to_delayed_work(work);
        forw_packet = container_of(delayed_work, struct batadv_forw_packet,
                                   delayed_work);
        bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);

        if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
                dropped = true;
                goto out;
        }

        batadv_iv_ogm_emit(forw_packet);

        /* we have to have at least one packet in the queue to determine the
         * queues wake up time unless we are shutting down.
         *
         * only re-schedule if this is the "original" copy, e.g. the OGM of the
         * primary interface should only be rescheduled once per period, but
         * this function will be called for the forw_packet instances of the
         * other secondary interfaces as well.
         */
        if (forw_packet->own &&
            forw_packet->if_incoming == forw_packet->if_outgoing)
                batadv_iv_ogm_schedule(forw_packet->if_incoming);

out:
        /* do we get something for free()? */
        if (batadv_forw_packet_steal(forw_packet,
                                     &bat_priv->forw_bat_list_lock))
                batadv_forw_packet_free(forw_packet, dropped);
}

static int batadv_iv_ogm_receive(struct sk_buff *skb,
                                 struct batadv_hard_iface *if_incoming)
{
        struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batadv_ogm_packet *ogm_packet;
        u8 *packet_pos;
        int ogm_offset;
        bool res;
        int ret = NET_RX_DROP;

        res = batadv_check_management_packet(skb, if_incoming, BATADV_OGM_HLEN);
        if (!res)
                goto free_skb;

        /* did we receive a B.A.T.M.A.N. IV OGM packet on an interface
         * that does not have B.A.T.M.A.N. IV enabled ?
         */
        if (bat_priv->algo_ops->iface.enable != batadv_iv_ogm_iface_enable)
                goto free_skb;

        batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
        batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
                           skb->len + ETH_HLEN);

        ogm_offset = 0;
        ogm_packet = (struct batadv_ogm_packet *)skb->data;

        /* unpack the aggregated packets and process them one by one */
        while (batadv_iv_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
                                         ogm_packet)) {
                batadv_iv_ogm_process(skb, ogm_offset, if_incoming);

                ogm_offset += BATADV_OGM_HLEN;
                ogm_offset += ntohs(ogm_packet->tvlv_len);

                packet_pos = skb->data + ogm_offset;
                ogm_packet = (struct batadv_ogm_packet *)packet_pos;
        }

        ret = NET_RX_SUCCESS;

free_skb:
        if (ret == NET_RX_SUCCESS)
                consume_skb(skb);
        else
                kfree_skb(skb);

        return ret;
}

/**
 * batadv_iv_ogm_neigh_get_tq_avg() - Get the TQ average for a neighbour on a
 *  given outgoing interface.
 * @neigh_node: Neighbour of interest
 * @if_outgoing: Outgoing interface of interest
 * @tq_avg: Pointer of where to store the TQ average
 *
 * Return: False if no average TQ available, otherwise true.
 */
static bool
batadv_iv_ogm_neigh_get_tq_avg(struct batadv_neigh_node *neigh_node,
                               struct batadv_hard_iface *if_outgoing,
                               u8 *tq_avg)
{
        struct batadv_neigh_ifinfo *n_ifinfo;

        n_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
        if (!n_ifinfo)
                return false;

        *tq_avg = n_ifinfo->bat_iv.tq_avg;
        batadv_neigh_ifinfo_put(n_ifinfo);

        return true;
}

/**
 * batadv_iv_ogm_orig_dump_subentry() - Dump an originator subentry 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
 * @if_outgoing: Limit dump to entries with this outgoing interface
 * @orig_node: Originator to dump
 * @neigh_node: Single hops neighbour
 * @best: Is the best originator
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_iv_ogm_orig_dump_subentry(struct sk_buff *msg, u32 portid, u32 seq,
                                 struct batadv_priv *bat_priv,
                                 struct batadv_hard_iface *if_outgoing,
                                 struct batadv_orig_node *orig_node,
                                 struct batadv_neigh_node *neigh_node,
                                 bool best)
{
        void *hdr;
        u8 tq_avg;
        unsigned int last_seen_msecs;

        last_seen_msecs = jiffies_to_msecs(jiffies - orig_node->last_seen);

        if (!batadv_iv_ogm_neigh_get_tq_avg(neigh_node, if_outgoing, &tq_avg))
                return 0;

        if (if_outgoing != BATADV_IF_DEFAULT &&
            if_outgoing != neigh_node->if_incoming)
                return 0;

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

        if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN,
                    orig_node->orig) ||
            nla_put(msg, BATADV_ATTR_NEIGH_ADDRESS, ETH_ALEN,
                    neigh_node->addr) ||
            nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
                           neigh_node->if_incoming->net_dev->name) ||
            nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
                        neigh_node->if_incoming->net_dev->ifindex) ||
            nla_put_u8(msg, BATADV_ATTR_TQ, tq_avg) ||
            nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS,
                        last_seen_msecs))
                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_iv_ogm_orig_dump_entry() - Dump an originator 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
 * @if_outgoing: Limit dump to entries with this outgoing interface
 * @orig_node: Originator to dump
 * @sub_s: Number of sub entries to skip
 *
 * This function assumes the caller holds rcu_read_lock().
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_iv_ogm_orig_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
                              struct batadv_priv *bat_priv,
                              struct batadv_hard_iface *if_outgoing,
                              struct batadv_orig_node *orig_node, int *sub_s)
{
        struct batadv_neigh_node *neigh_node_best;
        struct batadv_neigh_node *neigh_node;
        int sub = 0;
        bool best;
        u8 tq_avg_best;

        neigh_node_best = batadv_orig_router_get(orig_node, if_outgoing);
        if (!neigh_node_best)
                goto out;

        if (!batadv_iv_ogm_neigh_get_tq_avg(neigh_node_best, if_outgoing,
                                            &tq_avg_best))
                goto out;

        if (tq_avg_best == 0)
                goto out;

        hlist_for_each_entry_rcu(neigh_node, &orig_node->neigh_list, list) {
                if (sub++ < *sub_s)
                        continue;

                best = (neigh_node == neigh_node_best);

                if (batadv_iv_ogm_orig_dump_subentry(msg, portid, seq,
                                                     bat_priv, if_outgoing,
                                                     orig_node, neigh_node,
                                                     best)) {
                        batadv_neigh_node_put(neigh_node_best);

                        *sub_s = sub - 1;
                        return -EMSGSIZE;
                }
        }

 out:
        batadv_neigh_node_put(neigh_node_best);

        *sub_s = 0;
        return 0;
}

/**
 * batadv_iv_ogm_orig_dump_bucket() - Dump an originator 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
 * @if_outgoing: Limit dump to entries with this outgoing interface
 * @head: Bucket to be dumped
 * @idx_s: Number of entries to be skipped
 * @sub: Number of sub entries to be skipped
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_iv_ogm_orig_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
                               struct batadv_priv *bat_priv,
                               struct batadv_hard_iface *if_outgoing,
                               struct hlist_head *head, int *idx_s, int *sub)
{
        struct batadv_orig_node *orig_node;
        int idx = 0;

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

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

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

/**
 * batadv_iv_ogm_orig_dump() - Dump the originators into a message
 * @msg: Netlink message to dump into
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the soft interface information
 * @if_outgoing: Limit dump to entries with this outgoing interface
 */
static void
batadv_iv_ogm_orig_dump(struct sk_buff *msg, struct netlink_callback *cb,
                        struct batadv_priv *bat_priv,
                        struct batadv_hard_iface *if_outgoing)
{
        struct batadv_hashtable *hash = bat_priv->orig_hash;
        struct hlist_head *head;
        int bucket = cb->args[0];
        int idx = cb->args[1];
        int sub = cb->args[2];
        int portid = NETLINK_CB(cb->skb).portid;

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

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

                bucket++;
        }

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

/**
 * batadv_iv_ogm_neigh_diff() - calculate tq difference of two neighbors
 * @neigh1: the first neighbor object of the comparison
 * @if_outgoing1: outgoing interface for the first neighbor
 * @neigh2: the second neighbor object of the comparison
 * @if_outgoing2: outgoing interface for the second neighbor
 * @diff: pointer to integer receiving the calculated difference
 *
 * The content of *@diff is only valid when this function returns true.
 * It is less, equal to or greater than 0 if the metric via neigh1 is lower,
 * the same as or higher than the metric via neigh2
 *
 * Return: true when the difference could be calculated, false otherwise
 */
static bool batadv_iv_ogm_neigh_diff(struct batadv_neigh_node *neigh1,
                                     struct batadv_hard_iface *if_outgoing1,
                                     struct batadv_neigh_node *neigh2,
                                     struct batadv_hard_iface *if_outgoing2,
                                     int *diff)
{
        struct batadv_neigh_ifinfo *neigh1_ifinfo, *neigh2_ifinfo;
        u8 tq1, tq2;
        bool ret = true;

        neigh1_ifinfo = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
        neigh2_ifinfo = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);

        if (!neigh1_ifinfo || !neigh2_ifinfo) {
                ret = false;
                goto out;
        }

        tq1 = neigh1_ifinfo->bat_iv.tq_avg;
        tq2 = neigh2_ifinfo->bat_iv.tq_avg;
        *diff = (int)tq1 - (int)tq2;

out:
        batadv_neigh_ifinfo_put(neigh1_ifinfo);
        batadv_neigh_ifinfo_put(neigh2_ifinfo);

        return ret;
}

/**
 * batadv_iv_ogm_neigh_dump_neigh() - Dump a neighbour into a netlink message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @hardif_neigh: Neighbour to be dumped
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_iv_ogm_neigh_dump_neigh(struct sk_buff *msg, u32 portid, u32 seq,
                               struct batadv_hardif_neigh_node *hardif_neigh)
{
        void *hdr;
        unsigned int last_seen_msecs;

        last_seen_msecs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen);

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

        if (nla_put(msg, BATADV_ATTR_NEIGH_ADDRESS, ETH_ALEN,
                    hardif_neigh->addr) ||
            nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
                           hardif_neigh->if_incoming->net_dev->name) ||
            nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
                        hardif_neigh->if_incoming->net_dev->ifindex) ||
            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_iv_ogm_neigh_dump_hardif() - Dump the neighbours of a hard interface
 *  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
 * @hard_iface: Hard interface to dump the neighbours for
 * @idx_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_iv_ogm_neigh_dump_hardif(struct sk_buff *msg, u32 portid, u32 seq,
                                struct batadv_priv *bat_priv,
                                struct batadv_hard_iface *hard_iface,
                                int *idx_s)
{
        struct batadv_hardif_neigh_node *hardif_neigh;
        int idx = 0;

        hlist_for_each_entry_rcu(hardif_neigh,
                                 &hard_iface->neigh_list, list) {
                if (idx++ < *idx_s)
                        continue;

                if (batadv_iv_ogm_neigh_dump_neigh(msg, portid, seq,
                                                   hardif_neigh)) {
                        *idx_s = idx - 1;
                        return -EMSGSIZE;
                }
        }

        *idx_s = 0;
        return 0;
}

/**
 * batadv_iv_ogm_neigh_dump() - Dump the neighbours into a message
 * @msg: Netlink message to dump into
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the soft interface information
 * @single_hardif: Limit dump to this hard interface
 */
static void
batadv_iv_ogm_neigh_dump(struct sk_buff *msg, struct netlink_callback *cb,
                         struct batadv_priv *bat_priv,
                         struct batadv_hard_iface *single_hardif)
{
        struct batadv_hard_iface *hard_iface;
        int i_hardif = 0;
        int i_hardif_s = cb->args[0];
        int idx = cb->args[1];
        int portid = NETLINK_CB(cb->skb).portid;

        rcu_read_lock();
        if (single_hardif) {
                if (i_hardif_s == 0) {
                        if (batadv_iv_ogm_neigh_dump_hardif(msg, portid,
                                                            cb->nlh->nlmsg_seq,
                                                            bat_priv,
                                                            single_hardif,
                                                            &idx) == 0)
                                i_hardif++;
                }
        } else {
                list_for_each_entry_rcu(hard_iface, &batadv_hardif_list,
                                        list) {
                        if (hard_iface->soft_iface != bat_priv->soft_iface)
                                continue;

                        if (i_hardif++ < i_hardif_s)
                                continue;

                        if (batadv_iv_ogm_neigh_dump_hardif(msg, portid,
                                                            cb->nlh->nlmsg_seq,
                                                            bat_priv,
                                                            hard_iface, &idx)) {
                                i_hardif--;
                                break;
                        }
                }
        }
        rcu_read_unlock();

        cb->args[0] = i_hardif;
        cb->args[1] = idx;
}

/**
 * batadv_iv_ogm_neigh_cmp() - compare the metrics of two neighbors
 * @neigh1: the first neighbor object of the comparison
 * @if_outgoing1: outgoing interface for the first neighbor
 * @neigh2: the second neighbor object of the comparison
 * @if_outgoing2: outgoing interface for the second neighbor
 *
 * Return: a value less, equal to or greater than 0 if the metric via neigh1 is
 * lower, the same as or higher than the metric via neigh2
 */
static int batadv_iv_ogm_neigh_cmp(struct batadv_neigh_node *neigh1,
                                   struct batadv_hard_iface *if_outgoing1,
                                   struct batadv_neigh_node *neigh2,
                                   struct batadv_hard_iface *if_outgoing2)
{
        bool ret;
        int diff;

        ret = batadv_iv_ogm_neigh_diff(neigh1, if_outgoing1, neigh2,
                                       if_outgoing2, &diff);
        if (!ret)
                return 0;

        return diff;
}

/**
 * batadv_iv_ogm_neigh_is_sob() - check if neigh1 is similarly good or better
 *  than neigh2 from the metric prospective
 * @neigh1: the first neighbor object of the comparison
 * @if_outgoing1: outgoing interface for the first neighbor
 * @neigh2: the second neighbor object of the comparison
 * @if_outgoing2: outgoing interface for the second neighbor
 *
 * Return: true if the metric via neigh1 is equally good or better than
 * the metric via neigh2, false otherwise.
 */
static bool
batadv_iv_ogm_neigh_is_sob(struct batadv_neigh_node *neigh1,
                           struct batadv_hard_iface *if_outgoing1,
                           struct batadv_neigh_node *neigh2,
                           struct batadv_hard_iface *if_outgoing2)
{
        bool ret;
        int diff;

        ret = batadv_iv_ogm_neigh_diff(neigh1, if_outgoing1, neigh2,
                                       if_outgoing2, &diff);
        if (!ret)
                return false;

        ret = diff > -BATADV_TQ_SIMILARITY_THRESHOLD;
        return ret;
}

static void batadv_iv_iface_enabled(struct batadv_hard_iface *hard_iface)
{
        /* begin scheduling originator messages on that interface */
        batadv_iv_ogm_schedule(hard_iface);
}

/**
 * batadv_iv_init_sel_class() - initialize GW selection class
 * @bat_priv: the bat priv with all the soft interface information
 */
static void batadv_iv_init_sel_class(struct batadv_priv *bat_priv)
{
        /* set default TQ difference threshold to 20 */
        atomic_set(&bat_priv->gw.sel_class, 20);
}

static struct batadv_gw_node *
batadv_iv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
{
        struct batadv_neigh_node *router;
        struct batadv_neigh_ifinfo *router_ifinfo;
        struct batadv_gw_node *gw_node, *curr_gw = NULL;
        u64 max_gw_factor = 0;
        u64 tmp_gw_factor = 0;
        u8 max_tq = 0;
        u8 tq_avg;
        struct batadv_orig_node *orig_node;

        rcu_read_lock();
        hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {
                orig_node = gw_node->orig_node;
                router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
                if (!router)
                        continue;

                router_ifinfo = batadv_neigh_ifinfo_get(router,
                                                        BATADV_IF_DEFAULT);
                if (!router_ifinfo)
                        goto next;

                if (!kref_get_unless_zero(&gw_node->refcount))
                        goto next;

                tq_avg = router_ifinfo->bat_iv.tq_avg;

                switch (atomic_read(&bat_priv->gw.sel_class)) {
                case 1: /* fast connection */
                        tmp_gw_factor = tq_avg * tq_avg;
                        tmp_gw_factor *= gw_node->bandwidth_down;
                        tmp_gw_factor *= 100 * 100;
                        tmp_gw_factor >>= 18;

                        if (tmp_gw_factor > max_gw_factor ||
                            (tmp_gw_factor == max_gw_factor &&
                             tq_avg > max_tq)) {
                                batadv_gw_node_put(curr_gw);
                                curr_gw = gw_node;
                                kref_get(&curr_gw->refcount);
                        }
                        break;

                default: /* 2:  stable connection (use best statistic)
                          * 3:  fast-switch (use best statistic but change as
                          *     soon as a better gateway appears)
                          * XX: late-switch (use best statistic but change as
                          *     soon as a better gateway appears which has
                          *     $routing_class more tq points)
                          */
                        if (tq_avg > max_tq) {
                                batadv_gw_node_put(curr_gw);
                                curr_gw = gw_node;
                                kref_get(&curr_gw->refcount);
                        }
                        break;
                }

                if (tq_avg > max_tq)
                        max_tq = tq_avg;

                if (tmp_gw_factor > max_gw_factor)
                        max_gw_factor = tmp_gw_factor;

                batadv_gw_node_put(gw_node);

next:
                batadv_neigh_node_put(router);
                batadv_neigh_ifinfo_put(router_ifinfo);
        }
        rcu_read_unlock();

        return curr_gw;
}

static bool batadv_iv_gw_is_eligible(struct batadv_priv *bat_priv,
                                     struct batadv_orig_node *curr_gw_orig,
                                     struct batadv_orig_node *orig_node)
{
        struct batadv_neigh_ifinfo *router_orig_ifinfo = NULL;
        struct batadv_neigh_ifinfo *router_gw_ifinfo = NULL;
        struct batadv_neigh_node *router_gw = NULL;
        struct batadv_neigh_node *router_orig = NULL;
        u8 gw_tq_avg, orig_tq_avg;
        bool ret = false;

        /* dynamic re-election is performed only on fast or late switch */
        if (atomic_read(&bat_priv->gw.sel_class) <= 2)
                return false;

        router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
        if (!router_gw) {
                ret = true;
                goto out;
        }

        router_gw_ifinfo = batadv_neigh_ifinfo_get(router_gw,
                                                   BATADV_IF_DEFAULT);
        if (!router_gw_ifinfo) {
                ret = true;
                goto out;
        }

        router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
        if (!router_orig)
                goto out;

        router_orig_ifinfo = batadv_neigh_ifinfo_get(router_orig,
                                                     BATADV_IF_DEFAULT);
        if (!router_orig_ifinfo)
                goto out;

        gw_tq_avg = router_gw_ifinfo->bat_iv.tq_avg;
        orig_tq_avg = router_orig_ifinfo->bat_iv.tq_avg;

        /* the TQ value has to be better */
        if (orig_tq_avg < gw_tq_avg)
                goto out;

        /* if the routing class is greater than 3 the value tells us how much
         * greater the TQ value of the new gateway must be
         */
        if ((atomic_read(&bat_priv->gw.sel_class) > 3) &&
            (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw.sel_class)))
                goto out;

        batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
                   "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
                   gw_tq_avg, orig_tq_avg);

        ret = true;
out:
        batadv_neigh_ifinfo_put(router_gw_ifinfo);
        batadv_neigh_ifinfo_put(router_orig_ifinfo);
        batadv_neigh_node_put(router_gw);
        batadv_neigh_node_put(router_orig);

        return ret;
}

/**
 * batadv_iv_gw_dump_entry() - Dump a gateway into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the soft interface information
 * @gw_node: Gateway to be dumped
 *
 * Return: Error code, or 0 on success
 */
static int batadv_iv_gw_dump_entry(struct sk_buff *msg, u32 portid,
                                   struct netlink_callback *cb,
                                   struct batadv_priv *bat_priv,
                                   struct batadv_gw_node *gw_node)
{
        struct batadv_neigh_ifinfo *router_ifinfo = NULL;
        struct batadv_neigh_node *router;
        struct batadv_gw_node *curr_gw = NULL;
        int ret = 0;
        void *hdr;

        router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
        if (!router)
                goto out;

        router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
        if (!router_ifinfo)
                goto out;

        curr_gw = batadv_gw_get_selected_gw_node(bat_priv);

        hdr = genlmsg_put(msg, portid, cb->nlh->nlmsg_seq,
                          &batadv_netlink_family, NLM_F_MULTI,
                          BATADV_CMD_GET_GATEWAYS);
        if (!hdr) {
                ret = -ENOBUFS;
                goto out;
        }

        genl_dump_check_consistent(cb, hdr);

        ret = -EMSGSIZE;

        if (curr_gw == gw_node)
                if (nla_put_flag(msg, BATADV_ATTR_FLAG_BEST)) {
                        genlmsg_cancel(msg, hdr);
                        goto out;
                }

        if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN,
                    gw_node->orig_node->orig) ||
            nla_put_u8(msg, BATADV_ATTR_TQ, router_ifinfo->bat_iv.tq_avg) ||
            nla_put(msg, BATADV_ATTR_ROUTER, ETH_ALEN,
                    router->addr) ||
            nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
                           router->if_incoming->net_dev->name) ||
            nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
                        router->if_incoming->net_dev->ifindex) ||
            nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_DOWN,
                        gw_node->bandwidth_down) ||
            nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_UP,
                        gw_node->bandwidth_up)) {
                genlmsg_cancel(msg, hdr);
                goto out;
        }

        genlmsg_end(msg, hdr);
        ret = 0;

out:
        batadv_gw_node_put(curr_gw);
        batadv_neigh_ifinfo_put(router_ifinfo);
        batadv_neigh_node_put(router);
        return ret;
}

/**
 * batadv_iv_gw_dump() - Dump gateways into a message
 * @msg: Netlink message to dump into
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the soft interface information
 */
static void batadv_iv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb,
                              struct batadv_priv *bat_priv)
{
        int portid = NETLINK_CB(cb->skb).portid;
        struct batadv_gw_node *gw_node;
        int idx_skip = cb->args[0];
        int idx = 0;

        spin_lock_bh(&bat_priv->gw.list_lock);
        cb->seq = bat_priv->gw.generation << 1 | 1;

        hlist_for_each_entry(gw_node, &bat_priv->gw.gateway_list, list) {
                if (idx++ < idx_skip)
                        continue;

                if (batadv_iv_gw_dump_entry(msg, portid, cb, bat_priv,
                                            gw_node)) {
                        idx_skip = idx - 1;
                        goto unlock;
                }
        }

        idx_skip = idx;
unlock:
        spin_unlock_bh(&bat_priv->gw.list_lock);

        cb->args[0] = idx_skip;
}

static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
        .name = "BATMAN_IV",
        .iface = {
                .enable = batadv_iv_ogm_iface_enable,
                .enabled = batadv_iv_iface_enabled,
                .disable = batadv_iv_ogm_iface_disable,
                .update_mac = batadv_iv_ogm_iface_update_mac,
                .primary_set = batadv_iv_ogm_primary_iface_set,
        },
        .neigh = {
                .cmp = batadv_iv_ogm_neigh_cmp,
                .is_similar_or_better = batadv_iv_ogm_neigh_is_sob,
                .dump = batadv_iv_ogm_neigh_dump,
        },
        .orig = {
                .dump = batadv_iv_ogm_orig_dump,
        },
        .gw = {
                .init_sel_class = batadv_iv_init_sel_class,
                .get_best_gw_node = batadv_iv_gw_get_best_gw_node,
                .is_eligible = batadv_iv_gw_is_eligible,
                .dump = batadv_iv_gw_dump,
        },
};

/**
 * batadv_iv_init() - B.A.T.M.A.N. IV initialization function
 *
 * Return: 0 on success or negative error number in case of failure
 */
int __init batadv_iv_init(void)
{
        int ret;

        /* batman originator packet */
        ret = batadv_recv_handler_register(BATADV_IV_OGM,
                                           batadv_iv_ogm_receive);
        if (ret < 0)
                goto out;

        ret = batadv_algo_register(&batadv_batman_iv);
        if (ret < 0)
                goto handler_unregister;

        goto out;

handler_unregister:
        batadv_recv_handler_unregister(BATADV_IV_OGM);
out:
        return ret;
}