Add linux-next specific files for 20110831

[linux-2.6/next.git] / net / batman-adv / routing.c

/*
 * Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 *
 */

#include "main.h"
#include "routing.h"
#include "send.h"
#include "hash.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "icmp_socket.h"
#include "translation-table.h"
#include "originator.h"
#include "ring_buffer.h"
#include "vis.h"
#include "aggregation.h"
#include "gateway_common.h"
#include "gateway_client.h"
#include "unicast.h"

void slide_own_bcast_window(struct hard_iface *hard_iface)
{
        struct bat_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
        struct hashtable_t *hash = bat_priv->orig_hash;
        struct hlist_node *node;
        struct hlist_head *head;
        struct orig_node *orig_node;
        unsigned long *word;
        int i;
        size_t word_index;

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

                rcu_read_lock();
                hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
                        spin_lock_bh(&orig_node->ogm_cnt_lock);
                        word_index = hard_iface->if_num * NUM_WORDS;
                        word = &(orig_node->bcast_own[word_index]);

                        bit_get_packet(bat_priv, word, 1, 0);
                        orig_node->bcast_own_sum[hard_iface->if_num] =
                                bit_packet_count(word);
                        spin_unlock_bh(&orig_node->ogm_cnt_lock);
                }
                rcu_read_unlock();
        }
}

static void update_route(struct bat_priv *bat_priv,
                         struct orig_node *orig_node,
                         struct neigh_node *neigh_node)
{
        struct neigh_node *curr_router;

        curr_router = orig_node_get_router(orig_node);

        /* route deleted */
        if ((curr_router) && (!neigh_node)) {
                bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n",
                        orig_node->orig);
                tt_global_del_orig(bat_priv, orig_node,
                                    "Deleted route towards originator");

        /* route added */
        } else if ((!curr_router) && (neigh_node)) {

                bat_dbg(DBG_ROUTES, bat_priv,
                        "Adding route towards: %pM (via %pM)\n",
                        orig_node->orig, neigh_node->addr);
        /* route changed */
        } else if (neigh_node && curr_router) {
                bat_dbg(DBG_ROUTES, bat_priv,
                        "Changing route towards: %pM "
                        "(now via %pM - was via %pM)\n",
                        orig_node->orig, neigh_node->addr,
                        curr_router->addr);
        }

        if (curr_router)
                neigh_node_free_ref(curr_router);

        /* increase refcount of new best neighbor */
        if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
                neigh_node = NULL;

        spin_lock_bh(&orig_node->neigh_list_lock);
        rcu_assign_pointer(orig_node->router, neigh_node);
        spin_unlock_bh(&orig_node->neigh_list_lock);

        /* decrease refcount of previous best neighbor */
        if (curr_router)
                neigh_node_free_ref(curr_router);
}

void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node,
                   struct neigh_node *neigh_node)
{
        struct neigh_node *router = NULL;

        if (!orig_node)
                goto out;

        router = orig_node_get_router(orig_node);

        if (router != neigh_node)
                update_route(bat_priv, orig_node, neigh_node);

out:
        if (router)
                neigh_node_free_ref(router);
}

static int is_bidirectional_neigh(struct orig_node *orig_node,
                                struct orig_node *orig_neigh_node,
                                struct batman_packet *batman_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_packet->tq = ((batman_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_packet->tq);

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

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

/* caller must hold the neigh_list_lock */
void bonding_candidate_del(struct orig_node *orig_node,
                           struct neigh_node *neigh_node)
{
        /* this neighbor is not part of our candidate list */
        if (list_empty(&neigh_node->bonding_list))
                goto out;

        list_del_rcu(&neigh_node->bonding_list);
        INIT_LIST_HEAD(&neigh_node->bonding_list);
        neigh_node_free_ref(neigh_node);
        atomic_dec(&orig_node->bond_candidates);

out:
        return;
}

static void bonding_candidate_add(struct orig_node *orig_node,
                                  struct neigh_node *neigh_node)
{
        struct hlist_node *node;
        struct neigh_node *tmp_neigh_node, *router = NULL;
        uint8_t interference_candidate = 0;

        spin_lock_bh(&orig_node->neigh_list_lock);

        /* only consider if it has the same primary address ...  */
        if (!compare_eth(orig_node->orig,
                         neigh_node->orig_node->primary_addr))
                goto candidate_del;

        router = orig_node_get_router(orig_node);
        if (!router)
                goto candidate_del;

        /* ... and is good enough to be considered */
        if (neigh_node->tq_avg < router->tq_avg - BONDING_TQ_THRESHOLD)
                goto candidate_del;

        /**
         * check if we have another candidate with the same mac address or
         * interface. If we do, we won't select this candidate because of
         * possible interference.
         */
        hlist_for_each_entry_rcu(tmp_neigh_node, node,
                                 &orig_node->neigh_list, list) {

                if (tmp_neigh_node == neigh_node)
                        continue;

                /* we only care if the other candidate is even
                * considered as candidate. */
                if (list_empty(&tmp_neigh_node->bonding_list))
                        continue;

                if ((neigh_node->if_incoming == tmp_neigh_node->if_incoming) ||
                    (compare_eth(neigh_node->addr, tmp_neigh_node->addr))) {
                        interference_candidate = 1;
                        break;
                }
        }

        /* don't care further if it is an interference candidate */
        if (interference_candidate)
                goto candidate_del;

        /* this neighbor already is part of our candidate list */
        if (!list_empty(&neigh_node->bonding_list))
                goto out;

        if (!atomic_inc_not_zero(&neigh_node->refcount))
                goto out;

        list_add_rcu(&neigh_node->bonding_list, &orig_node->bond_list);
        atomic_inc(&orig_node->bond_candidates);
        goto out;

candidate_del:
        bonding_candidate_del(orig_node, neigh_node);

out:
        spin_unlock_bh(&orig_node->neigh_list_lock);

        if (router)
                neigh_node_free_ref(router);
}

/* copy primary address for bonding */
static void bonding_save_primary(const struct orig_node *orig_node,
                                 struct orig_node *orig_neigh_node,
                                 const struct batman_packet *batman_packet)
{
        if (!(batman_packet->flags & PRIMARIES_FIRST_HOP))
                return;

        memcpy(orig_neigh_node->primary_addr, orig_node->orig, ETH_ALEN);
}

static void update_orig(struct bat_priv *bat_priv, struct orig_node *orig_node,
                        const struct ethhdr *ethhdr,
                        const struct batman_packet *batman_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_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_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_packet->ttl;
                neigh_node->last_ttl = batman_packet->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_routes(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_packet->orig != ethhdr->h_source) &&
                                (batman_packet->ttl > 2)) ||
                                (batman_packet->flags & PRIMARIES_FIRST_HOP))
                tt_update_orig(bat_priv, orig_node, tt_buff,
                               batman_packet->tt_num_changes,
                               batman_packet->ttvn, batman_packet->tt_crc);

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

        orig_node->gw_flags = batman_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);
}

/* checks whether the host restarted and is in the protection time.
 * returns:
 *  0 if the packet is to be accepted
 *  1 if the packet is to be ignored.
 */
static int window_protected(struct bat_priv *bat_priv,
                            int32_t seq_num_diff,
                            unsigned long *last_reset)
{
        if ((seq_num_diff <= -TQ_LOCAL_WINDOW_SIZE)
                || (seq_num_diff >= EXPECTED_SEQNO_RANGE)) {
                if (time_after(jiffies, *last_reset +
                        msecs_to_jiffies(RESET_PROTECTION_MS))) {

                        *last_reset = jiffies;
                        bat_dbg(DBG_BATMAN, bat_priv,
                                "old packet received, start protection\n");

                        return 0;
                } else
                        return 1;
        }
        return 0;
}

/* 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 count_real_packets(const struct ethhdr *ethhdr,
                               const struct batman_packet *batman_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_packet->orig);
        if (!orig_node)
                return 0;

        spin_lock_bh(&orig_node->ogm_cnt_lock);
        seq_diff = batman_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_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_packet->seqno);
                orig_node->last_real_seqno = batman_packet->seqno;
        }

        ret = is_duplicate;

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

void receive_bat_packet(const struct ethhdr *ethhdr,
                        struct batman_packet *batman_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_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_packet->packet_type != BAT_PACKET)
                return;

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

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

        is_single_hop_neigh = (compare_eth(ethhdr->h_source,
                                           batman_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_packet->orig,
                batman_packet->prev_sender, batman_packet->seqno,
                batman_packet->ttvn, batman_packet->tt_crc,
                batman_packet->tt_num_changes, batman_packet->tq,
                batman_packet->ttl, batman_packet->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_packet->orig,
                                hard_iface->net_dev->dev_addr))
                        is_my_orig = 1;

                if (compare_eth(batman_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_packet->version != COMPAT_VERSION) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: incompatible batman version (%i)\n",
                        batman_packet->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_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_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_packet->orig);
        if (!orig_node)
                return;

        is_duplicate = count_real_packets(ethhdr, batman_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_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_packet->prev_sender)) &&
            !(compare_eth(batman_packet->orig, batman_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 = is_bidirectional_neigh(orig_node, orig_neigh_node,
                                                batman_packet, if_incoming);

        bonding_save_primary(orig_node, orig_neigh_node, batman_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_packet->seqno) &&
              (orig_node->last_ttl - 3 <= batman_packet->ttl))))
                update_orig(bat_priv, orig_node, ethhdr, batman_packet,
                            if_incoming, tt_buff, is_duplicate);

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

                /* mark direct link on incoming interface */
                schedule_forward_packet(orig_node, ethhdr, batman_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");
        schedule_forward_packet(orig_node, ethhdr, batman_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);
}

int recv_bat_packet(struct sk_buff *skb, struct hard_iface *hard_iface)
{
        struct ethhdr *ethhdr;

        /* drop packet if it has not necessary minimum size */
        if (unlikely(!pskb_may_pull(skb, sizeof(struct batman_packet))))
                return NET_RX_DROP;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* packet with broadcast indication but unicast recipient */
        if (!is_broadcast_ether_addr(ethhdr->h_dest))
                return NET_RX_DROP;

        /* packet with broadcast sender address */
        if (is_broadcast_ether_addr(ethhdr->h_source))
                return NET_RX_DROP;

        /* create a copy of the skb, if needed, to modify it. */
        if (skb_cow(skb, 0) < 0)
                return NET_RX_DROP;

        /* keep skb linear */
        if (skb_linearize(skb) < 0)
                return NET_RX_DROP;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        receive_aggr_bat_packet(ethhdr,
                                skb->data,
                                skb_headlen(skb),
                                hard_iface);

        kfree_skb(skb);
        return NET_RX_SUCCESS;
}

static int recv_my_icmp_packet(struct bat_priv *bat_priv,
                               struct sk_buff *skb, size_t icmp_len)
{
        struct hard_iface *primary_if = NULL;
        struct orig_node *orig_node = NULL;
        struct neigh_node *router = NULL;
        struct icmp_packet_rr *icmp_packet;
        int ret = NET_RX_DROP;

        icmp_packet = (struct icmp_packet_rr *)skb->data;

        /* add data to device queue */
        if (icmp_packet->msg_type != ECHO_REQUEST) {
                bat_socket_receive_packet(icmp_packet, icmp_len);
                goto out;
        }

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

        /* answer echo request (ping) */
        /* get routing information */
        orig_node = orig_hash_find(bat_priv, icmp_packet->orig);
        if (!orig_node)
                goto out;

        router = orig_node_get_router(orig_node);
        if (!router)
                goto out;

        /* create a copy of the skb, if needed, to modify it. */
        if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
                goto out;

        icmp_packet = (struct icmp_packet_rr *)skb->data;

        memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
        memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
        icmp_packet->msg_type = ECHO_REPLY;
        icmp_packet->ttl = TTL;

        send_skb_packet(skb, router->if_incoming, router->addr);
        ret = NET_RX_SUCCESS;

out:
        if (primary_if)
                hardif_free_ref(primary_if);
        if (router)
                neigh_node_free_ref(router);
        if (orig_node)
                orig_node_free_ref(orig_node);
        return ret;
}

static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,
                                  struct sk_buff *skb)
{
        struct hard_iface *primary_if = NULL;
        struct orig_node *orig_node = NULL;
        struct neigh_node *router = NULL;
        struct icmp_packet *icmp_packet;
        int ret = NET_RX_DROP;

        icmp_packet = (struct icmp_packet *)skb->data;

        /* send TTL exceeded if packet is an echo request (traceroute) */
        if (icmp_packet->msg_type != ECHO_REQUEST) {
                pr_debug("Warning - can't forward icmp packet from %pM to "
                         "%pM: ttl exceeded\n", icmp_packet->orig,
                         icmp_packet->dst);
                goto out;
        }

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

        /* get routing information */
        orig_node = orig_hash_find(bat_priv, icmp_packet->orig);
        if (!orig_node)
                goto out;

        router = orig_node_get_router(orig_node);
        if (!router)
                goto out;

        /* create a copy of the skb, if needed, to modify it. */
        if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
                goto out;

        icmp_packet = (struct icmp_packet *)skb->data;

        memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
        memcpy(icmp_packet->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
        icmp_packet->msg_type = TTL_EXCEEDED;
        icmp_packet->ttl = TTL;

        send_skb_packet(skb, router->if_incoming, router->addr);
        ret = NET_RX_SUCCESS;

out:
        if (primary_if)
                hardif_free_ref(primary_if);
        if (router)
                neigh_node_free_ref(router);
        if (orig_node)
                orig_node_free_ref(orig_node);
        return ret;
}


int recv_icmp_packet(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct icmp_packet_rr *icmp_packet;
        struct ethhdr *ethhdr;
        struct orig_node *orig_node = NULL;
        struct neigh_node *router = NULL;
        int hdr_size = sizeof(struct icmp_packet);
        int ret = NET_RX_DROP;

        /**
         * we truncate all incoming icmp packets if they don't match our size
         */
        if (skb->len >= sizeof(struct icmp_packet_rr))
                hdr_size = sizeof(struct icmp_packet_rr);

        /* drop packet if it has not necessary minimum size */
        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                goto out;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* packet with unicast indication but broadcast recipient */
        if (is_broadcast_ether_addr(ethhdr->h_dest))
                goto out;

        /* packet with broadcast sender address */
        if (is_broadcast_ether_addr(ethhdr->h_source))
                goto out;

        /* not for me */
        if (!is_my_mac(ethhdr->h_dest))
                goto out;

        icmp_packet = (struct icmp_packet_rr *)skb->data;

        /* add record route information if not full */
        if ((hdr_size == sizeof(struct icmp_packet_rr)) &&
            (icmp_packet->rr_cur < BAT_RR_LEN)) {
                memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
                        ethhdr->h_dest, ETH_ALEN);
                icmp_packet->rr_cur++;
        }

        /* packet for me */
        if (is_my_mac(icmp_packet->dst))
                return recv_my_icmp_packet(bat_priv, skb, hdr_size);

        /* TTL exceeded */
        if (icmp_packet->ttl < 2)
                return recv_icmp_ttl_exceeded(bat_priv, skb);

        /* get routing information */
        orig_node = orig_hash_find(bat_priv, icmp_packet->dst);
        if (!orig_node)
                goto out;

        router = orig_node_get_router(orig_node);
        if (!router)
                goto out;

        /* create a copy of the skb, if needed, to modify it. */
        if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
                goto out;

        icmp_packet = (struct icmp_packet_rr *)skb->data;

        /* decrement ttl */
        icmp_packet->ttl--;

        /* route it */
        send_skb_packet(skb, router->if_incoming, router->addr);
        ret = NET_RX_SUCCESS;

out:
        if (router)
                neigh_node_free_ref(router);
        if (orig_node)
                orig_node_free_ref(orig_node);
        return ret;
}

/* In the bonding case, send the packets in a round
 * robin fashion over the remaining interfaces.
 *
 * This method rotates the bonding list and increases the
 * returned router's refcount. */
static struct neigh_node *find_bond_router(struct orig_node *primary_orig,
                                           const struct hard_iface *recv_if)
{
        struct neigh_node *tmp_neigh_node;
        struct neigh_node *router = NULL, *first_candidate = NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
                                bonding_list) {
                if (!first_candidate)
                        first_candidate = tmp_neigh_node;

                /* recv_if == NULL on the first node. */
                if (tmp_neigh_node->if_incoming == recv_if)
                        continue;

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

                router = tmp_neigh_node;
                break;
        }

        /* use the first candidate if nothing was found. */
        if (!router && first_candidate &&
            atomic_inc_not_zero(&first_candidate->refcount))
                router = first_candidate;

        if (!router)
                goto out;

        /* selected should point to the next element
         * after the current router */
        spin_lock_bh(&primary_orig->neigh_list_lock);
        /* this is a list_move(), which unfortunately
         * does not exist as rcu version */
        list_del_rcu(&primary_orig->bond_list);
        list_add_rcu(&primary_orig->bond_list,
                     &router->bonding_list);
        spin_unlock_bh(&primary_orig->neigh_list_lock);

out:
        rcu_read_unlock();
        return router;
}

/* Interface Alternating: Use the best of the
 * remaining candidates which are not using
 * this interface.
 *
 * Increases the returned router's refcount */
static struct neigh_node *find_ifalter_router(struct orig_node *primary_orig,
                                              const struct hard_iface *recv_if)
{
        struct neigh_node *tmp_neigh_node;
        struct neigh_node *router = NULL, *first_candidate = NULL;

        rcu_read_lock();
        list_for_each_entry_rcu(tmp_neigh_node, &primary_orig->bond_list,
                                bonding_list) {
                if (!first_candidate)
                        first_candidate = tmp_neigh_node;

                /* recv_if == NULL on the first node. */
                if (tmp_neigh_node->if_incoming == recv_if)
                        continue;

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

                /* if we don't have a router yet
                 * or this one is better, choose it. */
                if ((!router) ||
                    (tmp_neigh_node->tq_avg > router->tq_avg)) {
                        /* decrement refcount of
                         * previously selected router */
                        if (router)
                                neigh_node_free_ref(router);

                        router = tmp_neigh_node;
                        atomic_inc_not_zero(&router->refcount);
                }

                neigh_node_free_ref(tmp_neigh_node);
        }

        /* use the first candidate if nothing was found. */
        if (!router && first_candidate &&
            atomic_inc_not_zero(&first_candidate->refcount))
                router = first_candidate;

        rcu_read_unlock();
        return router;
}

int recv_tt_query(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct tt_query_packet *tt_query;
        struct ethhdr *ethhdr;

        /* drop packet if it has not necessary minimum size */
        if (unlikely(!pskb_may_pull(skb, sizeof(struct tt_query_packet))))
                goto out;

        /* I could need to modify it */
        if (skb_cow(skb, sizeof(struct tt_query_packet)) < 0)
                goto out;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* packet with unicast indication but broadcast recipient */
        if (is_broadcast_ether_addr(ethhdr->h_dest))
                goto out;

        /* packet with broadcast sender address */
        if (is_broadcast_ether_addr(ethhdr->h_source))
                goto out;

        tt_query = (struct tt_query_packet *)skb->data;

        tt_query->tt_data = ntohs(tt_query->tt_data);

        switch (tt_query->flags & TT_QUERY_TYPE_MASK) {
        case TT_REQUEST:
                /* If we cannot provide an answer the tt_request is
                 * forwarded */
                if (!send_tt_response(bat_priv, tt_query)) {
                        bat_dbg(DBG_TT, bat_priv,
                                "Routing TT_REQUEST to %pM [%c]\n",
                                tt_query->dst,
                                (tt_query->flags & TT_FULL_TABLE ? 'F' : '.'));
                        tt_query->tt_data = htons(tt_query->tt_data);
                        return route_unicast_packet(skb, recv_if);
                }
                break;
        case TT_RESPONSE:
                /* packet needs to be linearized to access the TT changes */
                if (skb_linearize(skb) < 0)
                        goto out;

                if (is_my_mac(tt_query->dst))
                        handle_tt_response(bat_priv, tt_query);
                else {
                        bat_dbg(DBG_TT, bat_priv,
                                "Routing TT_RESPONSE to %pM [%c]\n",
                                tt_query->dst,
                                (tt_query->flags & TT_FULL_TABLE ? 'F' : '.'));
                        tt_query->tt_data = htons(tt_query->tt_data);
                        return route_unicast_packet(skb, recv_if);
                }
                break;
        }

out:
        /* returning NET_RX_DROP will make the caller function kfree the skb */
        return NET_RX_DROP;
}

int recv_roam_adv(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct roam_adv_packet *roam_adv_packet;
        struct orig_node *orig_node;
        struct ethhdr *ethhdr;

        /* drop packet if it has not necessary minimum size */
        if (unlikely(!pskb_may_pull(skb, sizeof(struct roam_adv_packet))))
                goto out;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* packet with unicast indication but broadcast recipient */
        if (is_broadcast_ether_addr(ethhdr->h_dest))
                goto out;

        /* packet with broadcast sender address */
        if (is_broadcast_ether_addr(ethhdr->h_source))
                goto out;

        roam_adv_packet = (struct roam_adv_packet *)skb->data;

        if (!is_my_mac(roam_adv_packet->dst))
                return route_unicast_packet(skb, recv_if);

        orig_node = orig_hash_find(bat_priv, roam_adv_packet->src);
        if (!orig_node)
                goto out;

        bat_dbg(DBG_TT, bat_priv, "Received ROAMING_ADV from %pM "
                "(client %pM)\n", roam_adv_packet->src,
                roam_adv_packet->client);

        tt_global_add(bat_priv, orig_node, roam_adv_packet->client,
                      atomic_read(&orig_node->last_ttvn) + 1, true, false);

        /* Roaming phase starts: I have new information but the ttvn has not
         * been incremented yet. This flag will make me check all the incoming
         * packets for the correct destination. */
        bat_priv->tt_poss_change = true;

        orig_node_free_ref(orig_node);
out:
        /* returning NET_RX_DROP will make the caller function kfree the skb */
        return NET_RX_DROP;
}

/* find a suitable router for this originator, and use
 * bonding if possible. increases the found neighbors
 * refcount.*/
struct neigh_node *find_router(struct bat_priv *bat_priv,
                               struct orig_node *orig_node,
                               const struct hard_iface *recv_if)
{
        struct orig_node *primary_orig_node;
        struct orig_node *router_orig;
        struct neigh_node *router;
        static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
        int bonding_enabled;

        if (!orig_node)
                return NULL;

        router = orig_node_get_router(orig_node);
        if (!router)
                goto err;

        /* without bonding, the first node should
         * always choose the default router. */
        bonding_enabled = atomic_read(&bat_priv->bonding);

        rcu_read_lock();
        /* select default router to output */
        router_orig = router->orig_node;
        if (!router_orig)
                goto err_unlock;

        if ((!recv_if) && (!bonding_enabled))
                goto return_router;

        /* if we have something in the primary_addr, we can search
         * for a potential bonding candidate. */
        if (compare_eth(router_orig->primary_addr, zero_mac))
                goto return_router;

        /* find the orig_node which has the primary interface. might
         * even be the same as our router_orig in many cases */

        if (compare_eth(router_orig->primary_addr, router_orig->orig)) {
                primary_orig_node = router_orig;
        } else {
                primary_orig_node = orig_hash_find(bat_priv,
                                                   router_orig->primary_addr);
                if (!primary_orig_node)
                        goto return_router;

                orig_node_free_ref(primary_orig_node);
        }

        /* with less than 2 candidates, we can't do any
         * bonding and prefer the original router. */
        if (atomic_read(&primary_orig_node->bond_candidates) < 2)
                goto return_router;

        /* all nodes between should choose a candidate which
         * is is not on the interface where the packet came
         * in. */

        neigh_node_free_ref(router);

        if (bonding_enabled)
                router = find_bond_router(primary_orig_node, recv_if);
        else
                router = find_ifalter_router(primary_orig_node, recv_if);

return_router:
        if (router && router->if_incoming->if_status != IF_ACTIVE)
                goto err_unlock;

        rcu_read_unlock();
        return router;
err_unlock:
        rcu_read_unlock();
err:
        if (router)
                neigh_node_free_ref(router);
        return NULL;
}

static int check_unicast_packet(struct sk_buff *skb, int hdr_size)
{
        struct ethhdr *ethhdr;

        /* drop packet if it has not necessary minimum size */
        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                return -1;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* packet with unicast indication but broadcast recipient */
        if (is_broadcast_ether_addr(ethhdr->h_dest))
                return -1;

        /* packet with broadcast sender address */
        if (is_broadcast_ether_addr(ethhdr->h_source))
                return -1;

        /* not for me */
        if (!is_my_mac(ethhdr->h_dest))
                return -1;

        return 0;
}

int route_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct orig_node *orig_node = NULL;
        struct neigh_node *neigh_node = NULL;
        struct unicast_packet *unicast_packet;
        struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
        int ret = NET_RX_DROP;
        struct sk_buff *new_skb;

        unicast_packet = (struct unicast_packet *)skb->data;

        /* TTL exceeded */
        if (unicast_packet->ttl < 2) {
                pr_debug("Warning - can't forward unicast packet from %pM to "
                         "%pM: ttl exceeded\n", ethhdr->h_source,
                         unicast_packet->dest);
                goto out;
        }

        /* get routing information */
        orig_node = orig_hash_find(bat_priv, unicast_packet->dest);

        if (!orig_node)
                goto out;

        /* find_router() increases neigh_nodes refcount if found. */
        neigh_node = find_router(bat_priv, orig_node, recv_if);

        if (!neigh_node)
                goto out;

        /* create a copy of the skb, if needed, to modify it. */
        if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
                goto out;

        unicast_packet = (struct unicast_packet *)skb->data;

        if (unicast_packet->packet_type == BAT_UNICAST &&
            atomic_read(&bat_priv->fragmentation) &&
            skb->len > neigh_node->if_incoming->net_dev->mtu) {
                ret = frag_send_skb(skb, bat_priv,
                                    neigh_node->if_incoming, neigh_node->addr);
                goto out;
        }

        if (unicast_packet->packet_type == BAT_UNICAST_FRAG &&
            frag_can_reassemble(skb, neigh_node->if_incoming->net_dev->mtu)) {

                ret = frag_reassemble_skb(skb, bat_priv, &new_skb);

                if (ret == NET_RX_DROP)
                        goto out;

                /* packet was buffered for late merge */
                if (!new_skb) {
                        ret = NET_RX_SUCCESS;
                        goto out;
                }

                skb = new_skb;
                unicast_packet = (struct unicast_packet *)skb->data;
        }

        /* decrement ttl */
        unicast_packet->ttl--;

        /* route it */
        send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
        ret = NET_RX_SUCCESS;

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

static int check_unicast_ttvn(struct bat_priv *bat_priv,
                               struct sk_buff *skb) {
        uint8_t curr_ttvn;
        struct orig_node *orig_node;
        struct ethhdr *ethhdr;
        struct hard_iface *primary_if;
        struct unicast_packet *unicast_packet;
        bool tt_poss_change;

        /* I could need to modify it */
        if (skb_cow(skb, sizeof(struct unicast_packet)) < 0)
                return 0;

        unicast_packet = (struct unicast_packet *)skb->data;

        if (is_my_mac(unicast_packet->dest)) {
                tt_poss_change = bat_priv->tt_poss_change;
                curr_ttvn = (uint8_t)atomic_read(&bat_priv->ttvn);
        } else {
                orig_node = orig_hash_find(bat_priv, unicast_packet->dest);

                if (!orig_node)
                        return 0;

                curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
                tt_poss_change = orig_node->tt_poss_change;
                orig_node_free_ref(orig_node);
        }

        /* Check whether I have to reroute the packet */
        if (seq_before(unicast_packet->ttvn, curr_ttvn) || tt_poss_change) {
                /* Linearize the skb before accessing it */
                if (skb_linearize(skb) < 0)
                        return 0;

                ethhdr = (struct ethhdr *)(skb->data +
                        sizeof(struct unicast_packet));
                orig_node = transtable_search(bat_priv, NULL, ethhdr->h_dest);

                if (!orig_node) {
                        if (!is_my_client(bat_priv, ethhdr->h_dest))
                                return 0;
                        primary_if = primary_if_get_selected(bat_priv);
                        if (!primary_if)
                                return 0;
                        memcpy(unicast_packet->dest,
                               primary_if->net_dev->dev_addr, ETH_ALEN);
                        hardif_free_ref(primary_if);
                } else {
                        memcpy(unicast_packet->dest, orig_node->orig,
                               ETH_ALEN);
                        curr_ttvn = (uint8_t)
                                atomic_read(&orig_node->last_ttvn);
                        orig_node_free_ref(orig_node);
                }

                bat_dbg(DBG_ROUTES, bat_priv, "TTVN mismatch (old_ttvn %u "
                        "new_ttvn %u)! Rerouting unicast packet (for %pM) to "
                        "%pM\n", unicast_packet->ttvn, curr_ttvn,
                        ethhdr->h_dest, unicast_packet->dest);

                unicast_packet->ttvn = curr_ttvn;
        }
        return 1;
}

int recv_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct unicast_packet *unicast_packet;
        int hdr_size = sizeof(*unicast_packet);

        if (check_unicast_packet(skb, hdr_size) < 0)
                return NET_RX_DROP;

        if (!check_unicast_ttvn(bat_priv, skb))
                return NET_RX_DROP;

        unicast_packet = (struct unicast_packet *)skb->data;

        /* packet for me */
        if (is_my_mac(unicast_packet->dest)) {
                interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
                return NET_RX_SUCCESS;
        }

        return route_unicast_packet(skb, recv_if);
}

int recv_ucast_frag_packet(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct unicast_frag_packet *unicast_packet;
        int hdr_size = sizeof(*unicast_packet);
        struct sk_buff *new_skb = NULL;
        int ret;

        if (check_unicast_packet(skb, hdr_size) < 0)
                return NET_RX_DROP;

        if (!check_unicast_ttvn(bat_priv, skb))
                return NET_RX_DROP;

        unicast_packet = (struct unicast_frag_packet *)skb->data;

        /* packet for me */
        if (is_my_mac(unicast_packet->dest)) {

                ret = frag_reassemble_skb(skb, bat_priv, &new_skb);

                if (ret == NET_RX_DROP)
                        return NET_RX_DROP;

                /* packet was buffered for late merge */
                if (!new_skb)
                        return NET_RX_SUCCESS;

                interface_rx(recv_if->soft_iface, new_skb, recv_if,
                             sizeof(struct unicast_packet));
                return NET_RX_SUCCESS;
        }

        return route_unicast_packet(skb, recv_if);
}


int recv_bcast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct orig_node *orig_node = NULL;
        struct bcast_packet *bcast_packet;
        struct ethhdr *ethhdr;
        int hdr_size = sizeof(*bcast_packet);
        int ret = NET_RX_DROP;
        int32_t seq_diff;

        /* drop packet if it has not necessary minimum size */
        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                goto out;

        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* packet with broadcast indication but unicast recipient */
        if (!is_broadcast_ether_addr(ethhdr->h_dest))
                goto out;

        /* packet with broadcast sender address */
        if (is_broadcast_ether_addr(ethhdr->h_source))
                goto out;

        /* ignore broadcasts sent by myself */
        if (is_my_mac(ethhdr->h_source))
                goto out;

        bcast_packet = (struct bcast_packet *)skb->data;

        /* ignore broadcasts originated by myself */
        if (is_my_mac(bcast_packet->orig))
                goto out;

        if (bcast_packet->ttl < 2)
                goto out;

        orig_node = orig_hash_find(bat_priv, bcast_packet->orig);

        if (!orig_node)
                goto out;

        spin_lock_bh(&orig_node->bcast_seqno_lock);

        /* check whether the packet is a duplicate */
        if (get_bit_status(orig_node->bcast_bits, orig_node->last_bcast_seqno,
                           ntohl(bcast_packet->seqno)))
                goto spin_unlock;

        seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;

        /* check whether the packet is old and the host just restarted. */
        if (window_protected(bat_priv, seq_diff,
                             &orig_node->bcast_seqno_reset))
                goto spin_unlock;

        /* mark broadcast in flood history, update window position
         * if required. */
        if (bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
                orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);

        spin_unlock_bh(&orig_node->bcast_seqno_lock);

        /* rebroadcast packet */
        add_bcast_packet_to_list(bat_priv, skb, 1);

        /* broadcast for me */
        interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
        ret = NET_RX_SUCCESS;
        goto out;

spin_unlock:
        spin_unlock_bh(&orig_node->bcast_seqno_lock);
out:
        if (orig_node)
                orig_node_free_ref(orig_node);
        return ret;
}

int recv_vis_packet(struct sk_buff *skb, struct hard_iface *recv_if)
{
        struct vis_packet *vis_packet;
        struct ethhdr *ethhdr;
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        int hdr_size = sizeof(*vis_packet);

        /* keep skb linear */
        if (skb_linearize(skb) < 0)
                return NET_RX_DROP;

        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                return NET_RX_DROP;

        vis_packet = (struct vis_packet *)skb->data;
        ethhdr = (struct ethhdr *)skb_mac_header(skb);

        /* not for me */
        if (!is_my_mac(ethhdr->h_dest))
                return NET_RX_DROP;

        /* ignore own packets */
        if (is_my_mac(vis_packet->vis_orig))
                return NET_RX_DROP;

        if (is_my_mac(vis_packet->sender_orig))
                return NET_RX_DROP;

        switch (vis_packet->vis_type) {
        case VIS_TYPE_SERVER_SYNC:
                receive_server_sync_packet(bat_priv, vis_packet,
                                           skb_headlen(skb));
                break;

        case VIS_TYPE_CLIENT_UPDATE:
                receive_client_update_packet(bat_priv, vis_packet,
                                             skb_headlen(skb));
                break;

        default:        /* ignore unknown packet */
                break;
        }

        /* We take a copy of the data in the packet, so we should
           always free the skbuf. */
        return NET_RX_DROP;
}