Merge branch 'v6v7' into devel

[linux/fpc-iii.git] / net / batman-adv / routing.c

/*
 * Copyright (C) 2007-2010 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 "types.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 batman_if *batman_if)
{
        struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);
        struct hashtable_t *hash = bat_priv->orig_hash;
        struct hlist_node *walk;
        struct hlist_head *head;
        struct element_t *bucket;
        struct orig_node *orig_node;
        unsigned long *word;
        int i;
        size_t word_index;

        spin_lock_bh(&bat_priv->orig_hash_lock);

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

                hlist_for_each_entry(bucket, walk, head, hlist) {
                        orig_node = bucket->data;
                        word_index = batman_if->if_num * NUM_WORDS;
                        word = &(orig_node->bcast_own[word_index]);

                        bit_get_packet(bat_priv, word, 1, 0);
                        orig_node->bcast_own_sum[batman_if->if_num] =
                                bit_packet_count(word);
                }
        }

        spin_unlock_bh(&bat_priv->orig_hash_lock);
}

static void update_HNA(struct bat_priv *bat_priv, struct orig_node *orig_node,
                       unsigned char *hna_buff, int hna_buff_len)
{
        if ((hna_buff_len != orig_node->hna_buff_len) ||
            ((hna_buff_len > 0) &&
             (orig_node->hna_buff_len > 0) &&
             (memcmp(orig_node->hna_buff, hna_buff, hna_buff_len) != 0))) {

                if (orig_node->hna_buff_len > 0)
                        hna_global_del_orig(bat_priv, orig_node,
                                            "originator changed hna");

                if ((hna_buff_len > 0) && (hna_buff))
                        hna_global_add_orig(bat_priv, orig_node,
                                            hna_buff, hna_buff_len);
        }
}

static void update_route(struct bat_priv *bat_priv,
                         struct orig_node *orig_node,
                         struct neigh_node *neigh_node,
                         unsigned char *hna_buff, int hna_buff_len)
{
        /* route deleted */
        if ((orig_node->router) && (!neigh_node)) {

                bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n",
                        orig_node->orig);
                hna_global_del_orig(bat_priv, orig_node,
                                    "originator timed out");

                /* route added */
        } else if ((!orig_node->router) && (neigh_node)) {

                bat_dbg(DBG_ROUTES, bat_priv,
                        "Adding route towards: %pM (via %pM)\n",
                        orig_node->orig, neigh_node->addr);
                hna_global_add_orig(bat_priv, orig_node,
                                    hna_buff, hna_buff_len);

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

        orig_node->router = neigh_node;
}


void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node,
                   struct neigh_node *neigh_node, unsigned char *hna_buff,
                   int hna_buff_len)
{

        if (!orig_node)
                return;

        if (orig_node->router != neigh_node)
                update_route(bat_priv, orig_node, neigh_node,
                             hna_buff, hna_buff_len);
        /* may be just HNA changed */
        else
                update_HNA(bat_priv, orig_node, hna_buff, hna_buff_len);
}

static int is_bidirectional_neigh(struct orig_node *orig_node,
                                struct orig_node *orig_neigh_node,
                                struct batman_packet *batman_packet,
                                struct batman_if *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
        unsigned char total_count;

        if (orig_node == orig_neigh_node) {
                list_for_each_entry(tmp_neigh_node,
                                    &orig_node->neigh_list,
                                    list) {

                        if (compare_orig(tmp_neigh_node->addr,
                                         orig_neigh_node->orig) &&
                            (tmp_neigh_node->if_incoming == if_incoming))
                                neigh_node = tmp_neigh_node;
                }

                if (!neigh_node)
                        neigh_node = create_neighbor(orig_node,
                                                     orig_neigh_node,
                                                     orig_neigh_node->orig,
                                                     if_incoming);
                /* create_neighbor failed, return 0 */
                if (!neigh_node)
                        return 0;

                neigh_node->last_valid = jiffies;
        } else {
                /* find packet count of corresponding one hop neighbor */
                list_for_each_entry(tmp_neigh_node,
                                    &orig_neigh_node->neigh_list, list) {

                        if (compare_orig(tmp_neigh_node->addr,
                                         orig_neigh_node->orig) &&
                            (tmp_neigh_node->if_incoming == if_incoming))
                                neigh_node = tmp_neigh_node;
                }

                if (!neigh_node)
                        neigh_node = create_neighbor(orig_neigh_node,
                                                     orig_neigh_node,
                                                     orig_neigh_node->orig,
                                                     if_incoming);
                /* create_neighbor failed, return 0 */
                if (!neigh_node)
                        return 0;
        }

        orig_node->last_valid = jiffies;

        /* pay attention to not get a value bigger than 100 % */
        total_count = (orig_neigh_node->bcast_own_sum[if_incoming->if_num] >
                       neigh_node->real_packet_count ?
                       neigh_node->real_packet_count :
                       orig_neigh_node->bcast_own_sum[if_incoming->if_num]);

        /* 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_node->real_packet_count < TQ_LOCAL_BIDRECT_RECV_MINIMUM))
                orig_neigh_node->tq_own = 0;
        else
                /* neigh_node->real_packet_count is never zero as we
                 * only purge old information when getting new
                 * information */
                orig_neigh_node->tq_own = (TQ_MAX_VALUE * total_count) /
                        neigh_node->real_packet_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
         */
        orig_neigh_node->tq_asym_penalty =
                TQ_MAX_VALUE -
                (TQ_MAX_VALUE *
                 (TQ_LOCAL_WINDOW_SIZE - neigh_node->real_packet_count) *
                 (TQ_LOCAL_WINDOW_SIZE - neigh_node->real_packet_count) *
                 (TQ_LOCAL_WINDOW_SIZE - neigh_node->real_packet_count)) /
                (TQ_LOCAL_WINDOW_SIZE *
                 TQ_LOCAL_WINDOW_SIZE *
                 TQ_LOCAL_WINDOW_SIZE);

        batman_packet->tq = ((batman_packet->tq *
                              orig_neigh_node->tq_own *
                              orig_neigh_node->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_node->real_packet_count, orig_neigh_node->tq_own,
                orig_neigh_node->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)
                return 1;

        return 0;
}

static void update_orig(struct bat_priv *bat_priv,
                        struct orig_node *orig_node,
                        struct ethhdr *ethhdr,
                        struct batman_packet *batman_packet,
                        struct batman_if *if_incoming,
                        unsigned char *hna_buff, int hna_buff_len,
                        char is_duplicate)
{
        struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
        int tmp_hna_buff_len;

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

        list_for_each_entry(tmp_neigh_node, &orig_node->neigh_list, list) {
                if (compare_orig(tmp_neigh_node->addr, ethhdr->h_source) &&
                    (tmp_neigh_node->if_incoming == if_incoming)) {
                        neigh_node = tmp_neigh_node;
                        continue;
                }

                if (is_duplicate)
                        continue;

                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);
        }

        if (!neigh_node) {
                struct orig_node *orig_tmp;

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

                neigh_node = create_neighbor(orig_node, orig_tmp,
                                             ethhdr->h_source, if_incoming);
                if (!neigh_node)
                        return;
        } else
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Updating existing last-hop neighbor of originator\n");

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

        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);

        if (!is_duplicate) {
                orig_node->last_ttl = batman_packet->ttl;
                neigh_node->last_ttl = batman_packet->ttl;
        }

        tmp_hna_buff_len = (hna_buff_len > batman_packet->num_hna * ETH_ALEN ?
                            batman_packet->num_hna * ETH_ALEN : hna_buff_len);

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

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

        /* if the TQ is the same and the link not more symetric we
         * won't consider it either */
        if ((orig_node->router) &&
             ((neigh_node->tq_avg == orig_node->router->tq_avg) &&
             (orig_node->router->orig_node->bcast_own_sum[if_incoming->if_num]
              >= neigh_node->orig_node->bcast_own_sum[if_incoming->if_num])))
                goto update_hna;

        update_routes(bat_priv, orig_node, neigh_node,
                      hna_buff, tmp_hna_buff_len);
        goto update_gw;

update_hna:
        update_routes(bat_priv, orig_node, orig_node->router,
                      hna_buff, tmp_hna_buff_len);

update_gw:
        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);
}

/* 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 char count_real_packets(struct ethhdr *ethhdr,
                               struct batman_packet *batman_packet,
                               struct batman_if *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct orig_node *orig_node;
        struct neigh_node *tmp_neigh_node;
        char is_duplicate = 0;
        int32_t seq_diff;
        int need_update = 0;
        int set_mark;

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

        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))
                return -1;

        list_for_each_entry(tmp_neigh_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_orig(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);
        }

        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;
        }

        return is_duplicate;
}

/* copy primary address for bonding */
static void mark_bonding_address(struct bat_priv *bat_priv,
                                 struct orig_node *orig_node,
                                 struct orig_node *orig_neigh_node,
                                 struct batman_packet *batman_packet)

{
        if (batman_packet->flags & PRIMARIES_FIRST_HOP)
                memcpy(orig_neigh_node->primary_addr,
                       orig_node->orig, ETH_ALEN);

        return;
}

/* mark possible bond.candidates in the neighbor list */
void update_bonding_candidates(struct bat_priv *bat_priv,
                               struct orig_node *orig_node)
{
        int candidates;
        int interference_candidate;
        int best_tq;
        struct neigh_node *tmp_neigh_node, *tmp_neigh_node2;
        struct neigh_node *first_candidate, *last_candidate;

        /* update the candidates for this originator */
        if (!orig_node->router) {
                orig_node->bond.candidates = 0;
                return;
        }

        best_tq = orig_node->router->tq_avg;

        /* update bond.candidates */

        candidates = 0;

        /* mark other nodes which also received "PRIMARIES FIRST HOP" packets
         * as "bonding partner" */

        /* first, zero the list */
        list_for_each_entry(tmp_neigh_node, &orig_node->neigh_list, list) {
                tmp_neigh_node->next_bond_candidate = NULL;
        }

        first_candidate = NULL;
        last_candidate = NULL;
        list_for_each_entry(tmp_neigh_node, &orig_node->neigh_list, list) {

                /* only consider if it has the same primary address ...  */
                if (memcmp(orig_node->orig,
                                tmp_neigh_node->orig_node->primary_addr,
                                ETH_ALEN) != 0)
                        continue;

                /* ... and is good enough to be considered */
                if (tmp_neigh_node->tq_avg < best_tq - BONDING_TQ_THRESHOLD)
                        continue;

                /* 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. */

                interference_candidate = 0;
                list_for_each_entry(tmp_neigh_node2,
                                &orig_node->neigh_list, list) {

                        if (tmp_neigh_node2 == tmp_neigh_node)
                                continue;

                        /* we only care if the other candidate is even
                         * considered as candidate. */
                        if (!tmp_neigh_node2->next_bond_candidate)
                                continue;


                        if ((tmp_neigh_node->if_incoming ==
                                tmp_neigh_node2->if_incoming)
                                || (memcmp(tmp_neigh_node->addr,
                                tmp_neigh_node2->addr, ETH_ALEN) == 0)) {

                                interference_candidate = 1;
                                break;
                        }
                }
                /* don't care further if it is an interference candidate */
                if (interference_candidate)
                        continue;

                if (!first_candidate) {
                        first_candidate = tmp_neigh_node;
                        tmp_neigh_node->next_bond_candidate = first_candidate;
                } else
                        tmp_neigh_node->next_bond_candidate = last_candidate;

                last_candidate = tmp_neigh_node;

                candidates++;
        }

        if (candidates > 0) {
                first_candidate->next_bond_candidate = last_candidate;
                orig_node->bond.selected = first_candidate;
        }

        orig_node->bond.candidates = candidates;
}

void receive_bat_packet(struct ethhdr *ethhdr,
                                struct batman_packet *batman_packet,
                                unsigned char *hna_buff, int hna_buff_len,
                                struct batman_if *if_incoming)
{
        struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
        struct batman_if *batman_if;
        struct orig_node *orig_neigh_node, *orig_node;
        char has_directlink_flag;
        char is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0;
        char is_broadcast = 0, is_bidirectional, is_single_hop_neigh;
        char 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_orig(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, tq %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->tq, batman_packet->ttl, batman_packet->version,
                has_directlink_flag);

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

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

                if (compare_orig(ethhdr->h_source,
                                 batman_if->net_dev->dev_addr))
                        is_my_addr = 1;

                if (compare_orig(batman_packet->orig,
                                 batman_if->net_dev->dev_addr))
                        is_my_orig = 1;

                if (compare_orig(batman_packet->prev_sender,
                                 batman_if->net_dev->dev_addr))
                        is_my_oldorig = 1;

                if (compare_orig(ethhdr->h_source, broadcast_addr))
                        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 */
                /* if received seqno equals last send seqno save new
                 * seqno for bidirectional check */
                if (has_directlink_flag &&
                    compare_orig(if_incoming->net_dev->dev_addr,
                                 batman_packet->orig) &&
                    (batman_packet->seqno - if_incoming_seqno + 2 == 0)) {
                        offset = if_incoming->if_num * NUM_WORDS;
                        word = &(orig_neigh_node->bcast_own[offset]);
                        bit_mark(word, 0);
                        orig_neigh_node->bcast_own_sum[if_incoming->if_num] =
                                bit_packet_count(word);
                }

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

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

        /* avoid temporary routing loops */
        if ((orig_node->router) &&
            (orig_node->router->orig_node->router) &&
            (compare_orig(orig_node->router->addr,
                          batman_packet->prev_sender)) &&
            !(compare_orig(batman_packet->orig, batman_packet->prev_sender)) &&
            (compare_orig(orig_node->router->addr,
                          orig_node->router->orig_node->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);
                return;
        }

        /* 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)
                return;

        /* drop packet if sender is not a direct neighbor and if we
         * don't route towards it */
        if (!is_single_hop_neigh && (!orig_neigh_node->router)) {
                bat_dbg(DBG_BATMAN, bat_priv,
                        "Drop packet: OGM via unknown neighbor!\n");
                return;
        }

        is_bidirectional = is_bidirectional_neigh(orig_node, orig_neigh_node,
                                                batman_packet, if_incoming);

        /* 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, hna_buff, hna_buff_len, is_duplicate);

        mark_bonding_address(bat_priv, orig_node,
                             orig_neigh_node, batman_packet);
        update_bonding_candidates(bat_priv, orig_node);

        /* 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, hna_buff_len, if_incoming);

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

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

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

        bat_dbg(DBG_BATMAN, bat_priv,
                "Forwarding packet: rebroadcast originator packet\n");
        schedule_forward_packet(orig_node, ethhdr, batman_packet,
                                0, hna_buff_len, if_incoming);
}

int recv_bat_packet(struct sk_buff *skb, struct batman_if *batman_if)
{
        struct bat_priv *bat_priv = netdev_priv(batman_if->soft_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);

        spin_lock_bh(&bat_priv->orig_hash_lock);
        receive_aggr_bat_packet(ethhdr,
                                skb->data,
                                skb_headlen(skb),
                                batman_if);
        spin_unlock_bh(&bat_priv->orig_hash_lock);

        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 orig_node *orig_node;
        struct icmp_packet_rr *icmp_packet;
        struct ethhdr *ethhdr;
        struct batman_if *batman_if;
        int ret;
        uint8_t dstaddr[ETH_ALEN];

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

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

        if (!bat_priv->primary_if)
                return NET_RX_DROP;

        /* answer echo request (ping) */
        /* get routing information */
        spin_lock_bh(&bat_priv->orig_hash_lock);
        orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
                                                   compare_orig, choose_orig,
                                                   icmp_packet->orig));
        ret = NET_RX_DROP;

        if ((orig_node) && (orig_node->router)) {

                /* don't lock while sending the packets ... we therefore
                 * copy the required data before sending */
                batman_if = orig_node->router->if_incoming;
                memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
                spin_unlock_bh(&bat_priv->orig_hash_lock);

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

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

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

                send_skb_packet(skb, batman_if, dstaddr);
                ret = NET_RX_SUCCESS;

        } else
                spin_unlock_bh(&bat_priv->orig_hash_lock);

        return ret;
}

static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,
                                  struct sk_buff *skb, size_t icmp_len)
{
        struct orig_node *orig_node;
        struct icmp_packet *icmp_packet;
        struct ethhdr *ethhdr;
        struct batman_if *batman_if;
        int ret;
        uint8_t dstaddr[ETH_ALEN];

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

        /* 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);
                return NET_RX_DROP;
        }

        if (!bat_priv->primary_if)
                return NET_RX_DROP;

        /* get routing information */
        spin_lock_bh(&bat_priv->orig_hash_lock);
        orig_node = ((struct orig_node *)
                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                               icmp_packet->orig));
        ret = NET_RX_DROP;

        if ((orig_node) && (orig_node->router)) {

                /* don't lock while sending the packets ... we therefore
                 * copy the required data before sending */
                batman_if = orig_node->router->if_incoming;
                memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
                spin_unlock_bh(&bat_priv->orig_hash_lock);

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

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

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

                send_skb_packet(skb, batman_if, dstaddr);
                ret = NET_RX_SUCCESS;

        } else
                spin_unlock_bh(&bat_priv->orig_hash_lock);

        return ret;
}


int recv_icmp_packet(struct sk_buff *skb, struct batman_if *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;
        struct batman_if *batman_if;
        int hdr_size = sizeof(struct icmp_packet);
        int ret;
        uint8_t dstaddr[ETH_ALEN];

        /**
         * 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)))
                return NET_RX_DROP;

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

        /* packet with unicast indication but broadcast 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;

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

        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, hdr_size);

        ret = NET_RX_DROP;

        /* get routing information */
        spin_lock_bh(&bat_priv->orig_hash_lock);
        orig_node = ((struct orig_node *)
                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                               icmp_packet->dst));

        if ((orig_node) && (orig_node->router)) {

                /* don't lock while sending the packets ... we therefore
                 * copy the required data before sending */
                batman_if = orig_node->router->if_incoming;
                memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
                spin_unlock_bh(&bat_priv->orig_hash_lock);

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

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

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

                /* route it */
                send_skb_packet(skb, batman_if, dstaddr);
                ret = NET_RX_SUCCESS;

        } else
                spin_unlock_bh(&bat_priv->orig_hash_lock);

        return ret;
}

/* find a suitable router for this originator, and use
 * bonding if possible. */
struct neigh_node *find_router(struct bat_priv *bat_priv,
                               struct orig_node *orig_node,
                               struct batman_if *recv_if)
{
        struct orig_node *primary_orig_node;
        struct orig_node *router_orig;
        struct neigh_node *router, *first_candidate, *best_router;
        static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
        int bonding_enabled;

        if (!orig_node)
                return NULL;

        if (!orig_node->router)
                return NULL;

        /* without bonding, the first node should
         * always choose the default router. */

        bonding_enabled = atomic_read(&bat_priv->bonding);

        if ((!recv_if) && (!bonding_enabled))
                return orig_node->router;

        router_orig = orig_node->router->orig_node;

        /* if we have something in the primary_addr, we can search
         * for a potential bonding candidate. */
        if (memcmp(router_orig->primary_addr, zero_mac, ETH_ALEN) == 0)
                return orig_node->router;

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

        if (memcmp(router_orig->primary_addr,
                                router_orig->orig, ETH_ALEN) == 0) {
                primary_orig_node = router_orig;
        } else {
                primary_orig_node = hash_find(bat_priv->orig_hash, compare_orig,
                                               choose_orig,
                                               router_orig->primary_addr);

                if (!primary_orig_node)
                        return orig_node->router;
        }

        /* with less than 2 candidates, we can't do any
         * bonding and prefer the original router. */

        if (primary_orig_node->bond.candidates < 2)
                return orig_node->router;


        /* all nodes between should choose a candidate which
         * is is not on the interface where the packet came
         * in. */
        first_candidate = primary_orig_node->bond.selected;
        router = first_candidate;

        if (bonding_enabled) {
                /* in the bonding case, send the packets in a round
                 * robin fashion over the remaining interfaces. */
                do {
                        /* recv_if == NULL on the first node. */
                        if (router->if_incoming != recv_if)
                                break;

                        router = router->next_bond_candidate;
                } while (router != first_candidate);

                primary_orig_node->bond.selected = router->next_bond_candidate;

        } else {
                /* if bonding is disabled, use the best of the
                 * remaining candidates which are not using
                 * this interface. */
                best_router = first_candidate;

                do {
                        /* recv_if == NULL on the first node. */
                        if ((router->if_incoming != recv_if) &&
                                (router->tq_avg > best_router->tq_avg))
                                        best_router = router;

                        router = router->next_bond_candidate;
                } while (router != first_candidate);

                router = best_router;
        }

        return router;
}

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 batman_if *recv_if,
                         int hdr_size)
{
        struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
        struct orig_node *orig_node;
        struct neigh_node *router;
        struct batman_if *batman_if;
        uint8_t dstaddr[ETH_ALEN];
        struct unicast_packet *unicast_packet;
        struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
        int ret;
        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);
                return NET_RX_DROP;
        }

        /* get routing information */
        spin_lock_bh(&bat_priv->orig_hash_lock);
        orig_node = ((struct orig_node *)
                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                               unicast_packet->dest));

        router = find_router(bat_priv, orig_node, recv_if);

        if (!router) {
                spin_unlock_bh(&bat_priv->orig_hash_lock);
                return NET_RX_DROP;
        }

        /* don't lock while sending the packets ... we therefore
         * copy the required data before sending */

        batman_if = router->if_incoming;
        memcpy(dstaddr, router->addr, ETH_ALEN);

        spin_unlock_bh(&bat_priv->orig_hash_lock);

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

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

        if (unicast_packet->packet_type == BAT_UNICAST &&
            atomic_read(&bat_priv->fragmentation) &&
            skb->len > batman_if->net_dev->mtu)
                return frag_send_skb(skb, bat_priv, batman_if,
                                     dstaddr);

        if (unicast_packet->packet_type == BAT_UNICAST_FRAG &&
            2 * skb->len - hdr_size <= batman_if->net_dev->mtu) {

                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;

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

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

        /* route it */
        send_skb_packet(skb, batman_if, dstaddr);

        return NET_RX_SUCCESS;
}

int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if)
{
        struct unicast_packet *unicast_packet;
        int hdr_size = sizeof(struct unicast_packet);

        if (check_unicast_packet(skb, hdr_size) < 0)
                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, hdr_size);
}

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

        if (check_unicast_packet(skb, hdr_size) < 0)
                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, hdr_size);
}


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

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

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

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

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

        if (bcast_packet->ttl < 2)
                return NET_RX_DROP;

        spin_lock_bh(&bat_priv->orig_hash_lock);
        orig_node = ((struct orig_node *)
                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                               bcast_packet->orig));

        if (!orig_node) {
                spin_unlock_bh(&bat_priv->orig_hash_lock);
                return NET_RX_DROP;
        }

        /* check whether the packet is a duplicate */
        if (get_bit_status(orig_node->bcast_bits,
                           orig_node->last_bcast_seqno,
                           ntohl(bcast_packet->seqno))) {
                spin_unlock_bh(&bat_priv->orig_hash_lock);
                return NET_RX_DROP;
        }

        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)) {
                spin_unlock_bh(&bat_priv->orig_hash_lock);
                return NET_RX_DROP;
        }

        /* 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(&bat_priv->orig_hash_lock);
        /* rebroadcast packet */
        add_bcast_packet_to_list(bat_priv, skb);

        /* broadcast for me */
        interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);

        return NET_RX_SUCCESS;
}

int recv_vis_packet(struct sk_buff *skb, struct batman_if *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(struct 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;
}