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

#include "main.h"
#include "translation-table.h"
#include "ring_buffer.h"
#include "originator.h"
#include "routing.h"
#include "gateway_common.h"
#include "gateway_client.h"
#include "hard-interface.h"
#include "send.h"
#include "bat_algo.h"

static void bat_iv_ogm_init(struct hard_iface *hard_iface)
{
        struct batman_ogm_packet *batman_ogm_packet;

        hard_iface->packet_len = BATMAN_OGM_LEN;
        hard_iface->packet_buff = kmalloc(hard_iface->packet_len, GFP_ATOMIC);

        batman_ogm_packet = (struct batman_ogm_packet *)hard_iface->packet_buff;
        batman_ogm_packet->header.packet_type = BAT_OGM;
        batman_ogm_packet->header.version = COMPAT_VERSION;
        batman_ogm_packet->header.ttl = 2;
        batman_ogm_packet->flags = NO_FLAGS;
        batman_ogm_packet->tq = TQ_MAX_VALUE;
        batman_ogm_packet->tt_num_changes = 0;
        batman_ogm_packet->ttvn = 0;
}

static void bat_iv_ogm_init_primary(struct hard_iface *hard_iface)
{
        struct batman_ogm_packet *batman_ogm_packet;

        batman_ogm_packet = (struct batman_ogm_packet *)hard_iface->packet_buff;
        batman_ogm_packet->flags = PRIMARIES_FIRST_HOP;
        batman_ogm_packet->header.ttl = TTL;
}

static void bat_iv_ogm_update_mac(struct hard_iface *hard_iface)
{
        struct batman_ogm_packet *batman_ogm_packet;

        batman_ogm_packet = (struct batman_ogm_packet *)hard_iface->packet_buff;
        memcpy(batman_ogm_packet->orig,
               hard_iface->net_dev->dev_addr, ETH_ALEN);
        memcpy(batman_ogm_packet->prev_sender,
               hard_iface->net_dev->dev_addr, ETH_ALEN);
}

/* when do we schedule our own ogm to be sent */
static unsigned long bat_iv_ogm_emit_send_time(const struct bat_priv *bat_priv)
{
        return jiffies + msecs_to_jiffies(
                   atomic_read(&bat_priv->orig_interval) -
                   JITTER + (random32() % 2*JITTER));
}

/* when do we schedule a ogm packet to be sent */
static unsigned long bat_iv_ogm_fwd_send_time(void)
{
        return jiffies + msecs_to_jiffies(random32() % (JITTER/2));
}

/* apply hop penalty for a normal link */
static uint8_t hop_penalty(uint8_t tq, const struct bat_priv *bat_priv)
{
        int hop_penalty = atomic_read(&bat_priv->hop_penalty);
        return (tq * (TQ_MAX_VALUE - hop_penalty)) / (TQ_MAX_VALUE);
}

/* is there another aggregated packet here? */
static int bat_iv_ogm_aggr_packet(int buff_pos, int packet_len,
                                  int tt_num_changes)
{
        int next_buff_pos = buff_pos + BATMAN_OGM_LEN + tt_len(tt_num_changes);

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

/* send a batman ogm to a given interface */
static void bat_iv_ogm_send_to_if(struct forw_packet *forw_packet,
                                  struct hard_iface *hard_iface)
{
        struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
        char *fwd_str;
        uint8_t packet_num;
        int16_t buff_pos;
        struct batman_ogm_packet *batman_ogm_packet;
        struct sk_buff *skb;

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

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

        /* adjust all flags and log packets */
        while (bat_iv_ogm_aggr_packet(buff_pos, forw_packet->packet_len,
                                      batman_ogm_packet->tt_num_changes)) {

                /* we might have aggregated direct link packets with an
                 * ordinary base packet */
                if ((forw_packet->direct_link_flags & (1 << packet_num)) &&
                    (forw_packet->if_incoming == hard_iface))
                        batman_ogm_packet->flags |= DIRECTLINK;
                else
                        batman_ogm_packet->flags &= ~DIRECTLINK;

                fwd_str = (packet_num > 0 ? "Forwarding" : (forw_packet->own ?
                                                            "Sending own" :
                                                            "Forwarding"));
                bat_dbg(DBG_BATMAN, bat_priv,
                        "%s %spacket (originator %pM, seqno %d, TQ %d, TTL %d, IDF %s, ttvn %d) on interface %s [%pM]\n",
                        fwd_str, (packet_num > 0 ? "aggregated " : ""),
                        batman_ogm_packet->orig,
                        ntohl(batman_ogm_packet->seqno),
                        batman_ogm_packet->tq, batman_ogm_packet->header.ttl,
                        (batman_ogm_packet->flags & DIRECTLINK ?
                         "on" : "off"),
                        batman_ogm_packet->ttvn, hard_iface->net_dev->name,
                        hard_iface->net_dev->dev_addr);

                buff_pos += BATMAN_OGM_LEN +
                                tt_len(batman_ogm_packet->tt_num_changes);
                packet_num++;
                batman_ogm_packet = (struct batman_ogm_packet *)
                                        (forw_packet->skb->data + buff_pos);
        }

        /* create clone because function is called more than once */
        skb = skb_clone(forw_packet->skb, GFP_ATOMIC);
        if (skb)
                send_skb_packet(skb, hard_iface, broadcast_addr);
}

/* send a batman ogm packet */
static void bat_iv_ogm_emit(struct forw_packet *forw_packet)
{
        struct hard_iface *hard_iface;
        struct net_device *soft_iface;
        struct bat_priv *bat_priv;
        struct hard_iface *primary_if = NULL;
        struct batman_ogm_packet *batman_ogm_packet;
        unsigned char directlink;

        batman_ogm_packet = (struct batman_ogm_packet *)
                                                (forw_packet->skb->data);
        directlink = (batman_ogm_packet->flags & DIRECTLINK ? 1 : 0);

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

        soft_iface = forw_packet->if_incoming->soft_iface;
        bat_priv = netdev_priv(soft_iface);

        if (forw_packet->if_incoming->if_status != IF_ACTIVE)
                goto out;

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

        /* multihomed peer assumed */
        /* non-primary OGMs are only broadcasted on their interface */
        if ((directlink && (batman_ogm_packet->header.ttl == 1)) ||
            (forw_packet->own && (forw_packet->if_incoming != primary_if))) {

                /* FIXME: what about aggregated packets ? */
                bat_dbg(DBG_BATMAN, bat_priv,
                        "%s packet (originator %pM, seqno %d, TTL %d) on interface %s [%pM]\n",
                        (forw_packet->own ? "Sending own" : "Forwarding"),
                        batman_ogm_packet->orig,
                        ntohl(batman_ogm_packet->seqno),
                        batman_ogm_packet->header.ttl,
                        forw_packet->if_incoming->net_dev->name,
                        forw_packet->if_incoming->net_dev->dev_addr);

                /* skb is only used once and than forw_packet is free'd */
                send_skb_packet(forw_packet->skb, forw_packet->if_incoming,
                                broadcast_addr);
                forw_packet->skb = NULL;

                goto out;
        }

        /* broadcast on every interface */
        rcu_read_lock();
        list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
                if (hard_iface->soft_iface != soft_iface)
                        continue;

                bat_iv_ogm_send_to_if(forw_packet, hard_iface);
        }
        rcu_read_unlock();

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

/* return true if new_packet can be aggregated with forw_packet */
static bool bat_iv_ogm_can_aggregate(const struct batman_ogm_packet
                                                        *new_batman_ogm_packet,
                                     struct bat_priv *bat_priv,
                                     int packet_len, unsigned long send_time,
                                     bool directlink,
                                     const struct hard_iface *if_incoming,
                                     const struct forw_packet *forw_packet)
{
        struct batman_ogm_packet *batman_ogm_packet;
        int aggregated_bytes = forw_packet->packet_len + packet_len;
        struct hard_iface *primary_if = NULL;
        bool res = false;

        batman_ogm_packet = (struct batman_ogm_packet *)forw_packet->skb->data;

        /**
         * we can aggregate the current packet to this aggregated packet
         * if:
         *
         * - the send time is within our MAX_AGGREGATION_MS time
         * - the resulting packet wont be bigger than
         *   MAX_AGGREGATION_BYTES
         */

        if (time_before(send_time, forw_packet->send_time) &&
            time_after_eq(send_time + msecs_to_jiffies(MAX_AGGREGATION_MS),
                                        forw_packet->send_time) &&
            (aggregated_bytes <= MAX_AGGREGATION_BYTES)) {

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

                /* packets without direct link flag and high TTL
                 * are flooded through the net  */
                if ((!directlink) &&
                    (!(batman_ogm_packet->flags & DIRECTLINK)) &&
                    (batman_ogm_packet->header.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_batman_ogm_packet->header.ttl == 1) &&
                    (forw_packet->if_incoming == if_incoming) &&

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

out:
        if (primary_if)
                hardif_free_ref(primary_if);
        return res;
}

/* create a new aggregated packet and add this packet to it */
static void bat_iv_ogm_aggregate_new(const unsigned char *packet_buff,
                                     int packet_len, unsigned long send_time,
                                     bool direct_link,
                                     struct hard_iface *if_incoming,
                                     int own_packet)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct forw_packet *forw_packet_aggr;
        unsigned char *skb_buff;

        if (!atomic_inc_not_zero(&if_incoming->refcount))
                return;

        /* own packet should always be scheduled */
        if (!own_packet) {
                if (!atomic_dec_not_zero(&bat_priv->batman_queue_left)) {
                        bat_dbg(DBG_BATMAN, bat_priv,
                                "batman packet queue full\n");
                        goto out;
                }
        }

        forw_packet_aggr = kmalloc(sizeof(*forw_packet_aggr), GFP_ATOMIC);
        if (!forw_packet_aggr) {
                if (!own_packet)
                        atomic_inc(&bat_priv->batman_queue_left);
                goto out;
        }

        if ((atomic_read(&bat_priv->aggregated_ogms)) &&
            (packet_len < MAX_AGGREGATION_BYTES))
                forw_packet_aggr->skb = dev_alloc_skb(MAX_AGGREGATION_BYTES +
                                                      sizeof(struct ethhdr));
        else
                forw_packet_aggr->skb = dev_alloc_skb(packet_len +
                                                      sizeof(struct ethhdr));

        if (!forw_packet_aggr->skb) {
                if (!own_packet)
                        atomic_inc(&bat_priv->batman_queue_left);
                kfree(forw_packet_aggr);
                goto out;
        }
        skb_reserve(forw_packet_aggr->skb, sizeof(struct ethhdr));

        INIT_HLIST_NODE(&forw_packet_aggr->list);

        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->if_incoming = if_incoming;
        forw_packet_aggr->num_packets = 0;
        forw_packet_aggr->direct_link_flags = 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;

        /* add new packet to packet list */
        spin_lock_bh(&bat_priv->forw_bat_list_lock);
        hlist_add_head(&forw_packet_aggr->list, &bat_priv->forw_bat_list);
        spin_unlock_bh(&bat_priv->forw_bat_list_lock);

        /* start timer for this packet */
        INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
                          send_outstanding_bat_ogm_packet);
        queue_delayed_work(bat_event_workqueue,
                           &forw_packet_aggr->delayed_work,
                           send_time - jiffies);

        return;
out:
        hardif_free_ref(if_incoming);
}

/* aggregate a new packet into the existing ogm packet */
static void bat_iv_ogm_aggregate(struct forw_packet *forw_packet_aggr,
                                 const unsigned char *packet_buff,
                                 int packet_len, bool direct_link)
{
        unsigned char *skb_buff;

        skb_buff = skb_put(forw_packet_aggr->skb, packet_len);
        memcpy(skb_buff, 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)
                forw_packet_aggr->direct_link_flags |=
                        (1 << forw_packet_aggr->num_packets);
}

static void bat_iv_ogm_queue_add(struct bat_priv *bat_priv,
                                 unsigned char *packet_buff,
                                 int packet_len, struct hard_iface *if_incoming,
                                 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 forw_packet *forw_packet_aggr = NULL, *forw_packet_pos = NULL;
        struct hlist_node *tmp_node;
        struct batman_ogm_packet *batman_ogm_packet;
        bool direct_link;

        batman_ogm_packet = (struct batman_ogm_packet *)packet_buff;
        direct_link = batman_ogm_packet->flags & DIRECTLINK ? 1 : 0;

        /* 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, tmp_node,
                                     &bat_priv->forw_bat_list, list) {
                        if (bat_iv_ogm_can_aggregate(batman_ogm_packet,
                                                     bat_priv, packet_len,
                                                     send_time, direct_link,
                                                     if_incoming,
                                                     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 += msecs_to_jiffies(MAX_AGGREGATION_MS);

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

static void bat_iv_ogm_forward(struct orig_node *orig_node,
                               const struct ethhdr *ethhdr,
                               struct batman_ogm_packet *batman_ogm_packet,
                               int directlink, struct hard_iface *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct neigh_node *router;
        uint8_t in_tq, in_ttl, tq_avg = 0;
        uint8_t tt_num_changes;

        if (batman_ogm_packet->header.ttl <= 1) {
                bat_dbg(DBG_BATMAN, bat_priv, "ttl exceeded\n");
                return;
        }

        router = orig_node_get_router(orig_node);

        in_tq = batman_ogm_packet->tq;
        in_ttl = batman_ogm_packet->header.ttl;
        tt_num_changes = batman_ogm_packet->tt_num_changes;

        batman_ogm_packet->header.ttl--;
        memcpy(batman_ogm_packet->prev_sender, ethhdr->h_source, ETH_ALEN);

        /* rebroadcast tq of our best ranking neighbor to ensure the rebroadcast
         * of our best tq value */
        if (router && router->tq_avg != 0) {

                /* rebroadcast ogm of best ranking neighbor as is */
                if (!compare_eth(router->addr, ethhdr->h_source)) {
                        batman_ogm_packet->tq = router->tq_avg;

                        if (router->last_ttl)
                                batman_ogm_packet->header.ttl =
                                        router->last_ttl - 1;
                }

                tq_avg = router->tq_avg;
        }

        if (router)
                neigh_node_free_ref(router);

        /* apply hop penalty */
        batman_ogm_packet->tq = hop_penalty(batman_ogm_packet->tq, bat_priv);

        bat_dbg(DBG_BATMAN, bat_priv,
                "Forwarding packet: tq_orig: %i, tq_avg: %i, tq_forw: %i, ttl_orig: %i, ttl_forw: %i\n",
                in_tq, tq_avg, batman_ogm_packet->tq, in_ttl - 1,
                batman_ogm_packet->header.ttl);

        batman_ogm_packet->seqno = htonl(batman_ogm_packet->seqno);
        batman_ogm_packet->tt_crc = htons(batman_ogm_packet->tt_crc);

        /* switch of primaries first hop flag when forwarding */
        batman_ogm_packet->flags &= ~PRIMARIES_FIRST_HOP;
        if (directlink)
                batman_ogm_packet->flags |= DIRECTLINK;
        else
                batman_ogm_packet->flags &= ~DIRECTLINK;

        bat_iv_ogm_queue_add(bat_priv, (unsigned char *)batman_ogm_packet,
                             BATMAN_OGM_LEN + tt_len(tt_num_changes),
                             if_incoming, 0, bat_iv_ogm_fwd_send_time());
}

static void bat_iv_ogm_schedule(struct hard_iface *hard_iface,
                                int tt_num_changes)
{
        struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
        struct batman_ogm_packet *batman_ogm_packet;
        struct hard_iface *primary_if;
        int vis_server;

        vis_server = atomic_read(&bat_priv->vis_mode);
        primary_if = primary_if_get_selected(bat_priv);

        batman_ogm_packet = (struct batman_ogm_packet *)hard_iface->packet_buff;

        /* change sequence number to network order */
        batman_ogm_packet->seqno =
                        htonl((uint32_t)atomic_read(&hard_iface->seqno));

        batman_ogm_packet->ttvn = atomic_read(&bat_priv->ttvn);
        batman_ogm_packet->tt_crc = htons((uint16_t)
                                                atomic_read(&bat_priv->tt_crc));
        if (tt_num_changes >= 0)
                batman_ogm_packet->tt_num_changes = tt_num_changes;

        if (vis_server == VIS_TYPE_SERVER_SYNC)
                batman_ogm_packet->flags |= VIS_SERVER;
        else
                batman_ogm_packet->flags &= ~VIS_SERVER;

        if ((hard_iface == primary_if) &&
            (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER))
                batman_ogm_packet->gw_flags =
                                (uint8_t)atomic_read(&bat_priv->gw_bandwidth);
        else
                batman_ogm_packet->gw_flags = NO_FLAGS;

        atomic_inc(&hard_iface->seqno);

        slide_own_bcast_window(hard_iface);
        bat_iv_ogm_queue_add(bat_priv, hard_iface->packet_buff,
                             hard_iface->packet_len, hard_iface, 1,
                             bat_iv_ogm_emit_send_time(bat_priv));

        if (primary_if)
                hardif_free_ref(primary_if);
}

static void bat_iv_ogm_orig_update(struct bat_priv *bat_priv,
                                   struct orig_node *orig_node,
                                   const struct ethhdr *ethhdr,
                                   const struct batman_ogm_packet
                                                        *batman_ogm_packet,
                                   struct hard_iface *if_incoming,
                                   const unsigned char *tt_buff,
                                   int is_duplicate)
{
        struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
        struct neigh_node *router = NULL;
        struct orig_node *orig_node_tmp;
        struct hlist_node *node;
        uint8_t bcast_own_sum_orig, bcast_own_sum_neigh;

        bat_dbg(DBG_BATMAN, bat_priv,
                "update_originator(): Searching and updating originator entry of received packet\n");

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_node, node,
                                 &orig_node->neigh_list, list) {
                if (compare_eth(tmp_neigh_node->addr, ethhdr->h_source) &&
                    (tmp_neigh_node->if_incoming == if_incoming) &&
                     atomic_inc_not_zero(&tmp_neigh_node->refcount)) {
                        if (neigh_node)
                                neigh_node_free_ref(neigh_node);
                        neigh_node = tmp_neigh_node;
                        continue;
                }

                if (is_duplicate)
                        continue;

                spin_lock_bh(&tmp_neigh_node->tq_lock);
                ring_buffer_set(tmp_neigh_node->tq_recv,
                                &tmp_neigh_node->tq_index, 0);
                tmp_neigh_node->tq_avg =
                        ring_buffer_avg(tmp_neigh_node->tq_recv);
                spin_unlock_bh(&tmp_neigh_node->tq_lock);
        }

        if (!neigh_node) {
                struct orig_node *orig_tmp;

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

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

                orig_node_free_ref(orig_tmp);
                if (!neigh_node)
                        goto unlock;
        } else
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Updating existing last-hop neighbor of originator\n");

        rcu_read_unlock();

        orig_node->flags = batman_ogm_packet->flags;
        neigh_node->last_valid = jiffies;

        spin_lock_bh(&neigh_node->tq_lock);
        ring_buffer_set(neigh_node->tq_recv,
                        &neigh_node->tq_index,
                        batman_ogm_packet->tq);
        neigh_node->tq_avg = ring_buffer_avg(neigh_node->tq_recv);
        spin_unlock_bh(&neigh_node->tq_lock);

        if (!is_duplicate) {
                orig_node->last_ttl = batman_ogm_packet->header.ttl;
                neigh_node->last_ttl = batman_ogm_packet->header.ttl;
        }

        bonding_candidate_add(orig_node, neigh_node);

        /* if this neighbor already is our next hop there is nothing
         * to change */
        router = orig_node_get_router(orig_node);
        if (router == neigh_node)
                goto update_tt;

        /* if this neighbor does not offer a better TQ we won't consider it */
        if (router && (router->tq_avg > neigh_node->tq_avg))
                goto update_tt;

        /* if the TQ is the same and the link not more symmetric we
         * won't consider it either */
        if (router && (neigh_node->tq_avg == router->tq_avg)) {
                orig_node_tmp = router->orig_node;
                spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
                bcast_own_sum_orig =
                        orig_node_tmp->bcast_own_sum[if_incoming->if_num];
                spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

                orig_node_tmp = neigh_node->orig_node;
                spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
                bcast_own_sum_neigh =
                        orig_node_tmp->bcast_own_sum[if_incoming->if_num];
                spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

                if (bcast_own_sum_orig >= bcast_own_sum_neigh)
                        goto update_tt;
        }

        update_route(bat_priv, orig_node, neigh_node);

update_tt:
        /* I have to check for transtable changes only if the OGM has been
         * sent through a primary interface */
        if (((batman_ogm_packet->orig != ethhdr->h_source) &&
             (batman_ogm_packet->header.ttl > 2)) ||
            (batman_ogm_packet->flags & PRIMARIES_FIRST_HOP))
                tt_update_orig(bat_priv, orig_node, tt_buff,
                               batman_ogm_packet->tt_num_changes,
                               batman_ogm_packet->ttvn,
                               batman_ogm_packet->tt_crc);

        if (orig_node->gw_flags != batman_ogm_packet->gw_flags)
                gw_node_update(bat_priv, orig_node,
                               batman_ogm_packet->gw_flags);

        orig_node->gw_flags = batman_ogm_packet->gw_flags;

        /* restart gateway selection if fast or late switching was enabled */
        if ((orig_node->gw_flags) &&
            (atomic_read(&bat_priv->gw_mode) == GW_MODE_CLIENT) &&
            (atomic_read(&bat_priv->gw_sel_class) > 2))
                gw_check_election(bat_priv, orig_node);

        goto out;

unlock:
        rcu_read_unlock();
out:
        if (neigh_node)
                neigh_node_free_ref(neigh_node);
        if (router)
                neigh_node_free_ref(router);
}

static int bat_iv_ogm_calc_tq(struct orig_node *orig_node,
                              struct orig_node *orig_neigh_node,
                              struct batman_ogm_packet *batman_ogm_packet,
                              struct hard_iface *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct neigh_node *neigh_node = NULL, *tmp_neigh_node;
        struct hlist_node *node;
        uint8_t total_count;
        uint8_t orig_eq_count, neigh_rq_count, tq_own;
        int tq_asym_penalty, ret = 0;

        /* find corresponding one hop neighbor */
        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_node, node,
                                 &orig_neigh_node->neigh_list, list) {

                if (!compare_eth(tmp_neigh_node->addr, orig_neigh_node->orig))
                        continue;

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

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

                neigh_node = tmp_neigh_node;
                break;
        }
        rcu_read_unlock();

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

        if (!neigh_node)
                goto out;

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

        orig_node->last_valid = jiffies;

        /* find packet count of corresponding one hop neighbor */
        spin_lock_bh(&orig_node->ogm_cnt_lock);
        orig_eq_count = orig_neigh_node->bcast_own_sum[if_incoming->if_num];
        neigh_rq_count = neigh_node->real_packet_count;
        spin_unlock_bh(&orig_node->ogm_cnt_lock);

        /* pay attention to not get a value bigger than 100 % */
        total_count = (orig_eq_count > neigh_rq_count ?
                       neigh_rq_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 < TQ_LOCAL_BIDRECT_SEND_MINIMUM) ||
            (neigh_rq_count < 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 = (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
         */
        tq_asym_penalty = TQ_MAX_VALUE - (TQ_MAX_VALUE *
                                (TQ_LOCAL_WINDOW_SIZE - neigh_rq_count) *
                                (TQ_LOCAL_WINDOW_SIZE - neigh_rq_count) *
                                (TQ_LOCAL_WINDOW_SIZE - neigh_rq_count)) /
                                        (TQ_LOCAL_WINDOW_SIZE *
                                         TQ_LOCAL_WINDOW_SIZE *
                                         TQ_LOCAL_WINDOW_SIZE);

        batman_ogm_packet->tq = ((batman_ogm_packet->tq * tq_own
                                                        * tq_asym_penalty) /
                                                (TQ_MAX_VALUE * TQ_MAX_VALUE));

        bat_dbg(DBG_BATMAN, bat_priv,
                "bidirectional: orig = %-15pM neigh = %-15pM => own_bcast = %2i, real recv = %2i, local tq: %3i, asym_penalty: %3i, total tq: %3i\n",
                orig_node->orig, orig_neigh_node->orig, total_count,
                neigh_rq_count, tq_own, tq_asym_penalty, batman_ogm_packet->tq);

        /* if link has the minimum required transmission quality
         * consider it bidirectional */
        if (batman_ogm_packet->tq >= TQ_TOTAL_BIDRECT_LIMIT)
                ret = 1;

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

/* processes a batman packet for all interfaces, adjusts the sequence number and
 * finds out whether it is a duplicate.
 * returns:
 *   1 the packet is a duplicate
 *   0 the packet has not yet been received
 *  -1 the packet is old and has been received while the seqno window
 *     was protected. Caller should drop it.
 */
static int bat_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
                                    const struct batman_ogm_packet
                                                        *batman_ogm_packet,
                                    const struct hard_iface *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct orig_node *orig_node;
        struct neigh_node *tmp_neigh_node;
        struct hlist_node *node;
        int is_duplicate = 0;
        int32_t seq_diff;
        int need_update = 0;
        int set_mark, ret = -1;

        orig_node = get_orig_node(bat_priv, batman_ogm_packet->orig);
        if (!orig_node)
                return 0;

        spin_lock_bh(&orig_node->ogm_cnt_lock);
        seq_diff = batman_ogm_packet->seqno - orig_node->last_real_seqno;

        /* signalize caller that the packet is to be dropped. */
        if (window_protected(bat_priv, seq_diff,
                             &orig_node->batman_seqno_reset))
                goto out;

        rcu_read_lock();
        hlist_for_each_entry_rcu(tmp_neigh_node, node,
                                 &orig_node->neigh_list, list) {

                is_duplicate |= get_bit_status(tmp_neigh_node->real_bits,
                                               orig_node->last_real_seqno,
                                               batman_ogm_packet->seqno);

                if (compare_eth(tmp_neigh_node->addr, ethhdr->h_source) &&
                    (tmp_neigh_node->if_incoming == if_incoming))
                        set_mark = 1;
                else
                        set_mark = 0;

                /* if the window moved, set the update flag. */
                need_update |= bit_get_packet(bat_priv,
                                              tmp_neigh_node->real_bits,
                                              seq_diff, set_mark);

                tmp_neigh_node->real_packet_count =
                        bit_packet_count(tmp_neigh_node->real_bits);
        }
        rcu_read_unlock();

        if (need_update) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "updating last_seqno: old %d, new %d\n",
                        orig_node->last_real_seqno, batman_ogm_packet->seqno);
                orig_node->last_real_seqno = batman_ogm_packet->seqno;
        }

        ret = is_duplicate;

out:
        spin_unlock_bh(&orig_node->ogm_cnt_lock);
        orig_node_free_ref(orig_node);
        return ret;
}

static void bat_iv_ogm_process(const struct ethhdr *ethhdr,
                               struct batman_ogm_packet *batman_ogm_packet,
                               const unsigned char *tt_buff,
                               struct hard_iface *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct hard_iface *hard_iface;
        struct orig_node *orig_neigh_node, *orig_node;
        struct neigh_node *router = NULL, *router_router = NULL;
        struct neigh_node *orig_neigh_router = NULL;
        int has_directlink_flag;
        int is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0;
        int is_broadcast = 0, is_bidirectional, is_single_hop_neigh;
        int is_duplicate;
        uint32_t if_incoming_seqno;

        /* 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
         * batman_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 (batman_ogm_packet->header.packet_type != BAT_OGM)
                return;

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

        has_directlink_flag = (batman_ogm_packet->flags & DIRECTLINK ? 1 : 0);

        is_single_hop_neigh = (compare_eth(ethhdr->h_source,
                                           batman_ogm_packet->orig) ? 1 : 0);

        bat_dbg(DBG_BATMAN, bat_priv,
                "Received BATMAN packet via NB: %pM, IF: %s [%pM] (from OG: %pM, via prev OG: %pM, seqno %d, ttvn %u, crc %u, changes %u, td %d, TTL %d, V %d, IDF %d)\n",
                ethhdr->h_source, if_incoming->net_dev->name,
                if_incoming->net_dev->dev_addr, batman_ogm_packet->orig,
                batman_ogm_packet->prev_sender, batman_ogm_packet->seqno,
                batman_ogm_packet->ttvn, batman_ogm_packet->tt_crc,
                batman_ogm_packet->tt_num_changes, batman_ogm_packet->tq,
                batman_ogm_packet->header.ttl,
                batman_ogm_packet->header.version, has_directlink_flag);

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

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

                if (compare_eth(ethhdr->h_source,
                                hard_iface->net_dev->dev_addr))
                        is_my_addr = 1;

                if (compare_eth(batman_ogm_packet->orig,
                                hard_iface->net_dev->dev_addr))
                        is_my_orig = 1;

                if (compare_eth(batman_ogm_packet->prev_sender,
                                hard_iface->net_dev->dev_addr))
                        is_my_oldorig = 1;

                if (is_broadcast_ether_addr(ethhdr->h_source))
                        is_broadcast = 1;
        }
        rcu_read_unlock();

        if (batman_ogm_packet->header.version != COMPAT_VERSION) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: incompatible batman version (%i)\n",
                        batman_ogm_packet->header.version);
                return;
        }

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

        if (is_broadcast) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: ignoring all packets with broadcast source addr (sender: %pM)\n",
                        ethhdr->h_source);
                return;
        }

        if (is_my_orig) {
                unsigned long *word;
                int offset;

                orig_neigh_node = get_orig_node(bat_priv, ethhdr->h_source);
                if (!orig_neigh_node)
                        return;

                /* neighbor has to indicate direct link and it has to
                 * come via the corresponding interface */
                /* save packet seqno for bidirectional check */
                if (has_directlink_flag &&
                    compare_eth(if_incoming->net_dev->dev_addr,
                                batman_ogm_packet->orig)) {
                        offset = if_incoming->if_num * NUM_WORDS;

                        spin_lock_bh(&orig_neigh_node->ogm_cnt_lock);
                        word = &(orig_neigh_node->bcast_own[offset]);

                        bit_mark(word,
                                 if_incoming_seqno -
                                                batman_ogm_packet->seqno - 2);
                        orig_neigh_node->bcast_own_sum[if_incoming->if_num] =
                                bit_packet_count(word);
                        spin_unlock_bh(&orig_neigh_node->ogm_cnt_lock);
                }

                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: originator packet from myself (via neighbor)\n");
                orig_node_free_ref(orig_neigh_node);
                return;
        }

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

        orig_node = get_orig_node(bat_priv, batman_ogm_packet->orig);
        if (!orig_node)
                return;

        is_duplicate = bat_iv_ogm_update_seqnos(ethhdr, batman_ogm_packet,
                                                if_incoming);

        if (is_duplicate == -1) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: packet within seqno protection time (sender: %pM)\n",
                        ethhdr->h_source);
                goto out;
        }

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

        router = orig_node_get_router(orig_node);
        if (router)
                router_router = orig_node_get_router(router->orig_node);

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

        /* if sender is a direct neighbor the sender mac equals
         * originator mac */
        orig_neigh_node = (is_single_hop_neigh ?
                           orig_node :
                           get_orig_node(bat_priv, ethhdr->h_source));
        if (!orig_neigh_node)
                goto out;

        orig_neigh_router = orig_node_get_router(orig_neigh_node);

        /* 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)) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: OGM via unknown neighbor!\n");
                goto out_neigh;
        }

        is_bidirectional = bat_iv_ogm_calc_tq(orig_node, orig_neigh_node,
                                              batman_ogm_packet, if_incoming);

        bonding_save_primary(orig_node, orig_neigh_node, batman_ogm_packet);

        /* update ranking if it is not a duplicate or has the same
         * seqno and similar ttl as the non-duplicate */
        if (is_bidirectional &&
            (!is_duplicate ||
             ((orig_node->last_real_seqno == batman_ogm_packet->seqno) &&
              (orig_node->last_ttl - 3 <= batman_ogm_packet->header.ttl))))
                bat_iv_ogm_orig_update(bat_priv, orig_node, ethhdr,
                                       batman_ogm_packet, if_incoming,
                                       tt_buff, is_duplicate);

        /* is single hop (direct) neighbor */
        if (is_single_hop_neigh) {

                /* mark direct link on incoming interface */
                bat_iv_ogm_forward(orig_node, ethhdr, batman_ogm_packet,
                                   1, if_incoming);

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

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

        if (is_duplicate) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: duplicate packet received\n");
                goto out_neigh;
        }

        bat_dbg(DBG_BATMAN, bat_priv,
                "Forwarding packet: rebroadcast originator packet\n");
        bat_iv_ogm_forward(orig_node, ethhdr, batman_ogm_packet,
                           0, if_incoming);

out_neigh:
        if ((orig_neigh_node) && (!is_single_hop_neigh))
                orig_node_free_ref(orig_neigh_node);
out:
        if (router)
                neigh_node_free_ref(router);
        if (router_router)
                neigh_node_free_ref(router_router);
        if (orig_neigh_router)
                neigh_node_free_ref(orig_neigh_router);

        orig_node_free_ref(orig_node);
}

static void bat_iv_ogm_receive(struct hard_iface *if_incoming,
                               struct sk_buff *skb)
{
        struct batman_ogm_packet *batman_ogm_packet;
        struct ethhdr *ethhdr;
        int buff_pos = 0, packet_len;
        unsigned char *tt_buff, *packet_buff;

        packet_len = skb_headlen(skb);
        ethhdr = (struct ethhdr *)skb_mac_header(skb);
        packet_buff = skb->data;
        batman_ogm_packet = (struct batman_ogm_packet *)packet_buff;

        /* unpack the aggregated packets and process them one by one */
        do {
                /* network to host order for our 32bit seqno and the
                   orig_interval */
                batman_ogm_packet->seqno = ntohl(batman_ogm_packet->seqno);
                batman_ogm_packet->tt_crc = ntohs(batman_ogm_packet->tt_crc);

                tt_buff = packet_buff + buff_pos + BATMAN_OGM_LEN;

                bat_iv_ogm_process(ethhdr, batman_ogm_packet,
                                   tt_buff, if_incoming);

                buff_pos += BATMAN_OGM_LEN +
                                tt_len(batman_ogm_packet->tt_num_changes);

                batman_ogm_packet = (struct batman_ogm_packet *)
                                                (packet_buff + buff_pos);
        } while (bat_iv_ogm_aggr_packet(buff_pos, packet_len,
                                        batman_ogm_packet->tt_num_changes));
}

static struct bat_algo_ops batman_iv __read_mostly = {
        .name = "BATMAN IV",
        .bat_ogm_init = bat_iv_ogm_init,
        .bat_ogm_init_primary = bat_iv_ogm_init_primary,
        .bat_ogm_update_mac = bat_iv_ogm_update_mac,
        .bat_ogm_schedule = bat_iv_ogm_schedule,
        .bat_ogm_emit = bat_iv_ogm_emit,
        .bat_ogm_receive = bat_iv_ogm_receive,
};

int __init bat_iv_init(void)
{
        return bat_algo_register(&batman_iv);
}