bridge_loop_avoidance.c

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/* Copyright (C) 2011-2012 B.A.T.M.A.N. contributors:
 *
 * 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 "hash.h"
#include "hard-interface.h"
#include "originator.h"
#include "bridge_loop_avoidance.h"
#include "translation-table.h"
#include "send.h"

#include <linux/etherdevice.h>
#include <linux/crc16.h>
#include <linux/if_arp.h>
#include <net/arp.h>
#include <linux/if_vlan.h>

static const uint8_t batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};

static void batadv_bla_periodic_work(struct work_struct *work);
static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
                     struct batadv_backbone_gw *backbone_gw);

/* return the index of the claim */
static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
{
    const unsigned char *key = data;
    uint32_t hash = 0;
    size_t i;

    for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
        hash += key[i];
        hash += (hash << 10);
        hash ^= (hash >> 6);
    }

    hash += (hash << 3);
    hash ^= (hash >> 11);
    hash += (hash << 15);

    return hash % size;
}

/* return the index of the backbone gateway */
static inline uint32_t batadv_choose_backbone_gw(const void *data,
                         uint32_t size)
{
    const unsigned char *key = data;
    uint32_t hash = 0;
    size_t i;

    for (i = 0; i < ETH_ALEN + sizeof(short); i++) {
        hash += key[i];
        hash += (hash << 10);
        hash ^= (hash >> 6);
    }

    hash += (hash << 3);
    hash ^= (hash >> 11);
    hash += (hash << 15);

    return hash % size;
}


/* compares address and vid of two backbone gws */
static int batadv_compare_backbone_gw(const struct hlist_node *node,
                      const void *data2)
{
    const void *data1 = container_of(node, struct batadv_backbone_gw,
                     hash_entry);

    return (memcmp(data1, data2, ETH_ALEN + sizeof(short)) == 0 ? 1 : 0);
}

/* compares address and vid of two claims */
static int batadv_compare_claim(const struct hlist_node *node,
                const void *data2)
{
    const void *data1 = container_of(node, struct batadv_claim,
                     hash_entry);

    return (memcmp(data1, data2, ETH_ALEN + sizeof(short)) == 0 ? 1 : 0);
}

/* free a backbone gw */
static void batadv_backbone_gw_free_ref(struct batadv_backbone_gw *backbone_gw)
{
    if (atomic_dec_and_test(&backbone_gw->refcount))
        kfree_rcu(backbone_gw, rcu);
}

/* finally deinitialize the claim */
static void batadv_claim_free_rcu(struct rcu_head *rcu)
{
    struct batadv_claim *claim;

    claim = container_of(rcu, struct batadv_claim, rcu);

    batadv_backbone_gw_free_ref(claim->backbone_gw);
    kfree(claim);
}

/* free a claim, call claim_free_rcu if its the last reference */
static void batadv_claim_free_ref(struct batadv_claim *claim)
{
    if (atomic_dec_and_test(&claim->refcount))
        call_rcu(&claim->rcu, batadv_claim_free_rcu);
}

/* @bat_priv: the bat priv with all the soft interface information
 * @data: search data (may be local/static data)
 *
 * looks for a claim in the hash, and returns it if found
 * or NULL otherwise.
 */
static struct batadv_claim *batadv_claim_hash_find(struct batadv_priv *bat_priv,
                           struct batadv_claim *data)
{
    struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
    struct hlist_head *head;
    struct hlist_node *node;
    struct batadv_claim *claim;
    struct batadv_claim *claim_tmp = NULL;
    int index;

    if (!hash)
        return NULL;

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

    rcu_read_lock();
    hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
        if (!batadv_compare_claim(&claim->hash_entry, data))
            continue;

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

        claim_tmp = claim;
        break;
    }
    rcu_read_unlock();

    return claim_tmp;
}

static struct batadv_backbone_gw *
batadv_backbone_hash_find(struct batadv_priv *bat_priv,
              uint8_t *addr, short vid)
{
    struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
    struct hlist_head *head;
    struct hlist_node *node;
    struct batadv_backbone_gw search_entry, *backbone_gw;
    struct batadv_backbone_gw *backbone_gw_tmp = NULL;
    int index;

    if (!hash)
        return NULL;

    memcpy(search_entry.orig, addr, ETH_ALEN);
    search_entry.vid = vid;

    index = batadv_choose_backbone_gw(&search_entry, hash->size);
    head = &hash->table[index];

    rcu_read_lock();
    hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
        if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
                        &search_entry))
            continue;

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

        backbone_gw_tmp = backbone_gw;
        break;
    }
    rcu_read_unlock();

    return backbone_gw_tmp;
}

/* delete all claims for a backbone */
static void
batadv_bla_del_backbone_claims(struct batadv_backbone_gw *backbone_gw)
{
    struct batadv_hashtable *hash;
    struct hlist_node *node, *node_tmp;
    struct hlist_head *head;
    struct batadv_claim *claim;
    int i;
    spinlock_t *list_lock;  /* protects write access to the hash lists */

    hash = backbone_gw->bat_priv->bla.claim_hash;
    if (!hash)
        return;

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

        spin_lock_bh(list_lock);
        hlist_for_each_entry_safe(claim, node, node_tmp,
                      head, hash_entry) {

            if (claim->backbone_gw != backbone_gw)
                continue;

            batadv_claim_free_ref(claim);
            hlist_del_rcu(node);
        }
        spin_unlock_bh(list_lock);
    }

    /* all claims gone, intialize CRC */
    backbone_gw->crc = BATADV_BLA_CRC_INIT;
}

static void batadv_bla_send_claim(struct batadv_priv *bat_priv, uint8_t *mac,
                  short vid, int claimtype)
{
    struct sk_buff *skb;
    struct ethhdr *ethhdr;
    struct batadv_hard_iface *primary_if;
    struct net_device *soft_iface;
    uint8_t *hw_src;
    struct batadv_bla_claim_dst local_claim_dest;
    __be32 zeroip = 0;

    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (!primary_if)
        return;

    memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
           sizeof(local_claim_dest));
    local_claim_dest.type = claimtype;

    soft_iface = primary_if->soft_iface;

    skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
             /* IP DST: 0.0.0.0 */
             zeroip,
             primary_if->soft_iface,
             /* IP SRC: 0.0.0.0 */
             zeroip,
             /* Ethernet DST: Broadcast */
             NULL,
             /* Ethernet SRC/HW SRC:  originator mac */
             primary_if->net_dev->dev_addr,
             /* HW DST: FF:43:05:XX:YY:YY
              * with XX   = claim type
              * and YY:YY = group id
              */
             (uint8_t *)&local_claim_dest);

    if (!skb)
        goto out;

    ethhdr = (struct ethhdr *)skb->data;
    hw_src = (uint8_t *)ethhdr + ETH_HLEN + sizeof(struct arphdr);

    /* now we pretend that the client would have sent this ... */
    switch (claimtype) {
    case BATADV_CLAIM_TYPE_CLAIM:
        /* normal claim frame
         * set Ethernet SRC to the clients mac
         */
        memcpy(ethhdr->h_source, mac, ETH_ALEN);
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_send_claim(): CLAIM %pM on vid %d\n", mac, vid);
        break;
    case BATADV_CLAIM_TYPE_UNCLAIM:
        /* unclaim frame
         * set HW SRC to the clients mac
         */
        memcpy(hw_src, mac, ETH_ALEN);
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
               vid);
        break;
    case BATADV_CLAIM_TYPE_ANNOUNCE:
        /* announcement frame
         * set HW SRC to the special mac containg the crc
         */
        memcpy(hw_src, mac, ETH_ALEN);
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
               ethhdr->h_source, vid);
        break;
    case BATADV_CLAIM_TYPE_REQUEST:
        /* request frame
         * set HW SRC and header destination to the receiving backbone
         * gws mac
         */
        memcpy(hw_src, mac, ETH_ALEN);
        memcpy(ethhdr->h_dest, mac, ETH_ALEN);
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_send_claim(): REQUEST of %pM to %pMon vid %d\n",
               ethhdr->h_source, ethhdr->h_dest, vid);
        break;

    }

    if (vid != -1)
        skb = vlan_insert_tag(skb, vid);

    skb_reset_mac_header(skb);
    skb->protocol = eth_type_trans(skb, soft_iface);
    batadv_inc_counter(bat_priv, BATADV_CNT_RX);
    batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
               skb->len + ETH_HLEN);
    soft_iface->last_rx = jiffies;

    netif_rx(skb);
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
}

static struct batadv_backbone_gw *
batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
               short vid)
{
    struct batadv_backbone_gw *entry;
    struct batadv_orig_node *orig_node;
    int hash_added;

    entry = batadv_backbone_hash_find(bat_priv, orig, vid);

    if (entry)
        return entry;

    batadv_dbg(BATADV_DBG_BLA, bat_priv,
           "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
           orig, vid);

    entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
    if (!entry)
        return NULL;

    entry->vid = vid;
    entry->lasttime = jiffies;
    entry->crc = BATADV_BLA_CRC_INIT;
    entry->bat_priv = bat_priv;
    atomic_set(&entry->request_sent, 0);
    memcpy(entry->orig, orig, ETH_ALEN);

    /* one for the hash, one for returning */
    atomic_set(&entry->refcount, 2);

    hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
                     batadv_compare_backbone_gw,
                     batadv_choose_backbone_gw, entry,
                     &entry->hash_entry);

    if (unlikely(hash_added != 0)) {
        /* hash failed, free the structure */
        kfree(entry);
        return NULL;
    }

    /* this is a gateway now, remove any tt entries */
    orig_node = batadv_orig_hash_find(bat_priv, orig);
    if (orig_node) {
        batadv_tt_global_del_orig(bat_priv, orig_node,
                      "became a backbone gateway");
        batadv_orig_node_free_ref(orig_node);
    }
    return entry;
}

/* update or add the own backbone gw to make sure we announce
 * where we receive other backbone gws
 */
static void
batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
                  struct batadv_hard_iface *primary_if,
                  short vid)
{
    struct batadv_backbone_gw *backbone_gw;

    backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
                         primary_if->net_dev->dev_addr,
                         vid);
    if (unlikely(!backbone_gw))
        return;

    backbone_gw->lasttime = jiffies;
    batadv_backbone_gw_free_ref(backbone_gw);
}

/* @bat_priv: the bat priv with all the soft interface information
 * @vid: the vid where the request came on
 *
 * Repeat all of our own claims, and finally send an ANNOUNCE frame
 * to allow the requester another check if the CRC is correct now.
 */
static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
                      struct batadv_hard_iface *primary_if,
                      short vid)
{
    struct hlist_node *node;
    struct hlist_head *head;
    struct batadv_hashtable *hash;
    struct batadv_claim *claim;
    struct batadv_backbone_gw *backbone_gw;
    int i;

    batadv_dbg(BATADV_DBG_BLA, bat_priv,
           "bla_answer_request(): received a claim request, send all of our own claims again\n");

    backbone_gw = batadv_backbone_hash_find(bat_priv,
                        primary_if->net_dev->dev_addr,
                        vid);
    if (!backbone_gw)
        return;

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

        rcu_read_lock();
        hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
            /* only own claims are interesting */
            if (claim->backbone_gw != backbone_gw)
                continue;

            batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
                          BATADV_CLAIM_TYPE_CLAIM);
        }
        rcu_read_unlock();
    }

    /* finally, send an announcement frame */
    batadv_bla_send_announce(bat_priv, backbone_gw);
    batadv_backbone_gw_free_ref(backbone_gw);
}

/* @backbone_gw: the backbone gateway from whom we are out of sync
 *
 * When the crc is wrong, ask the backbone gateway for a full table update.
 * After the request, it will repeat all of his own claims and finally
 * send an announcement claim with which we can check again.
 */
static void batadv_bla_send_request(struct batadv_backbone_gw *backbone_gw)
{
    /* first, remove all old entries */
    batadv_bla_del_backbone_claims(backbone_gw);

    batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
           "Sending REQUEST to %pM\n", backbone_gw->orig);

    /* send request */
    batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
                  backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);

    /* no local broadcasts should be sent or received, for now. */
    if (!atomic_read(&backbone_gw->request_sent)) {
        atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
        atomic_set(&backbone_gw->request_sent, 1);
    }
}

/* @bat_priv: the bat priv with all the soft interface information
 * @backbone_gw: our backbone gateway which should be announced
 *
 * This function sends an announcement. It is called from multiple
 * places.
 */
static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
                     struct batadv_backbone_gw *backbone_gw)
{
    uint8_t mac[ETH_ALEN];
    __be16 crc;

    memcpy(mac, batadv_announce_mac, 4);
    crc = htons(backbone_gw->crc);
    memcpy(&mac[4], &crc, 2);

    batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
                  BATADV_CLAIM_TYPE_ANNOUNCE);

}

static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
                 const uint8_t *mac, const short vid,
                 struct batadv_backbone_gw *backbone_gw)
{
    struct batadv_claim *claim;
    struct batadv_claim search_claim;
    int hash_added;

    memcpy(search_claim.addr, mac, ETH_ALEN);
    search_claim.vid = vid;
    claim = batadv_claim_hash_find(bat_priv, &search_claim);

    /* create a new claim entry if it does not exist yet. */
    if (!claim) {
        claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
        if (!claim)
            return;

        memcpy(claim->addr, mac, ETH_ALEN);
        claim->vid = vid;
        claim->lasttime = jiffies;
        claim->backbone_gw = backbone_gw;

        atomic_set(&claim->refcount, 2);
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
               mac, vid);
        hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
                         batadv_compare_claim,
                         batadv_choose_claim, claim,
                         &claim->hash_entry);

        if (unlikely(hash_added != 0)) {
            /* only local changes happened. */
            kfree(claim);
            return;
        }
    } else {
        claim->lasttime = jiffies;
        if (claim->backbone_gw == backbone_gw)
            /* no need to register a new backbone */
            goto claim_free_ref;

        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_add_claim(): changing ownership for %pM, vid %d\n",
               mac, vid);

        claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
        batadv_backbone_gw_free_ref(claim->backbone_gw);

    }
    /* set (new) backbone gw */
    atomic_inc(&backbone_gw->refcount);
    claim->backbone_gw = backbone_gw;

    backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
    backbone_gw->lasttime = jiffies;

claim_free_ref:
    batadv_claim_free_ref(claim);
}

/* Delete a claim from the claim hash which has the
 * given mac address and vid.
 */
static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
                 const uint8_t *mac, const short vid)
{
    struct batadv_claim search_claim, *claim;

    memcpy(search_claim.addr, mac, ETH_ALEN);
    search_claim.vid = vid;
    claim = batadv_claim_hash_find(bat_priv, &search_claim);
    if (!claim)
        return;

    batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
           mac, vid);

    batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
               batadv_choose_claim, claim);
    batadv_claim_free_ref(claim); /* reference from the hash is gone */

    claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);

    /* don't need the reference from hash_find() anymore */
    batadv_claim_free_ref(claim);
}

/* check for ANNOUNCE frame, return 1 if handled */
static int batadv_handle_announce(struct batadv_priv *bat_priv,
                  uint8_t *an_addr, uint8_t *backbone_addr,
                  short vid)
{
    struct batadv_backbone_gw *backbone_gw;
    uint16_t crc;

    if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
        return 0;

    backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);

    if (unlikely(!backbone_gw))
        return 1;


    /* handle as ANNOUNCE frame */
    backbone_gw->lasttime = jiffies;
    crc = ntohs(*((__be16 *)(&an_addr[4])));

    batadv_dbg(BATADV_DBG_BLA, bat_priv,
           "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %04x\n",
           vid, backbone_gw->orig, crc);

    if (backbone_gw->crc != crc) {
        batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
               "handle_announce(): CRC FAILED for %pM/%d (my = %04x, sent = %04x)\n",
               backbone_gw->orig, backbone_gw->vid,
               backbone_gw->crc, crc);

        batadv_bla_send_request(backbone_gw);
    } else {
        /* if we have sent a request and the crc was OK,
         * we can allow traffic again.
         */
        if (atomic_read(&backbone_gw->request_sent)) {
            atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
            atomic_set(&backbone_gw->request_sent, 0);
        }
    }

    batadv_backbone_gw_free_ref(backbone_gw);
    return 1;
}

/* check for REQUEST frame, return 1 if handled */
static int batadv_handle_request(struct batadv_priv *bat_priv,
                 struct batadv_hard_iface *primary_if,
                 uint8_t *backbone_addr,
                 struct ethhdr *ethhdr, short vid)
{
    /* check for REQUEST frame */
    if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
        return 0;

    /* sanity check, this should not happen on a normal switch,
     * we ignore it in this case.
     */
    if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
        return 1;

    batadv_dbg(BATADV_DBG_BLA, bat_priv,
           "handle_request(): REQUEST vid %d (sent by %pM)...\n",
           vid, ethhdr->h_source);

    batadv_bla_answer_request(bat_priv, primary_if, vid);
    return 1;
}

/* check for UNCLAIM frame, return 1 if handled */
static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
                 struct batadv_hard_iface *primary_if,
                 uint8_t *backbone_addr,
                 uint8_t *claim_addr, short vid)
{
    struct batadv_backbone_gw *backbone_gw;

    /* unclaim in any case if it is our own */
    if (primary_if && batadv_compare_eth(backbone_addr,
                         primary_if->net_dev->dev_addr))
        batadv_bla_send_claim(bat_priv, claim_addr, vid,
                      BATADV_CLAIM_TYPE_UNCLAIM);

    backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);

    if (!backbone_gw)
        return 1;

    /* this must be an UNCLAIM frame */
    batadv_dbg(BATADV_DBG_BLA, bat_priv,
           "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
           claim_addr, vid, backbone_gw->orig);

    batadv_bla_del_claim(bat_priv, claim_addr, vid);
    batadv_backbone_gw_free_ref(backbone_gw);
    return 1;
}

/* check for CLAIM frame, return 1 if handled */
static int batadv_handle_claim(struct batadv_priv *bat_priv,
                   struct batadv_hard_iface *primary_if,
                   uint8_t *backbone_addr, uint8_t *claim_addr,
                   short vid)
{
    struct batadv_backbone_gw *backbone_gw;

    /* register the gateway if not yet available, and add the claim. */

    backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid);

    if (unlikely(!backbone_gw))
        return 1;

    /* this must be a CLAIM frame */
    batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
    if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
        batadv_bla_send_claim(bat_priv, claim_addr, vid,
                      BATADV_CLAIM_TYPE_CLAIM);

    /* TODO: we could call something like tt_local_del() here. */

    batadv_backbone_gw_free_ref(backbone_gw);
    return 1;
}

static int batadv_check_claim_group(struct batadv_priv *bat_priv,
                    struct batadv_hard_iface *primary_if,
                    uint8_t *hw_src, uint8_t *hw_dst,
                    struct ethhdr *ethhdr)
{
    uint8_t *backbone_addr;
    struct batadv_orig_node *orig_node;
    struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;

    bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
    bla_dst_own = &bat_priv->bla.claim_dest;

    /* check if it is a claim packet in general */
    if (memcmp(bla_dst->magic, bla_dst_own->magic,
           sizeof(bla_dst->magic)) != 0)
        return 0;

    /* if announcement packet, use the source,
     * otherwise assume it is in the hw_src
     */
    switch (bla_dst->type) {
    case BATADV_CLAIM_TYPE_CLAIM:
        backbone_addr = hw_src;
        break;
    case BATADV_CLAIM_TYPE_REQUEST:
    case BATADV_CLAIM_TYPE_ANNOUNCE:
    case BATADV_CLAIM_TYPE_UNCLAIM:
        backbone_addr = ethhdr->h_source;
        break;
    default:
        return 0;
    }

    /* don't accept claim frames from ourselves */
    if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
        return 0;

    /* if its already the same group, it is fine. */
    if (bla_dst->group == bla_dst_own->group)
        return 2;

    /* lets see if this originator is in our mesh */
    orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);

    /* dont accept claims from gateways which are not in
     * the same mesh or group.
     */
    if (!orig_node)
        return 1;

    /* if our mesh friends mac is bigger, use it for ourselves. */
    if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "taking other backbones claim group: %04x\n",
               ntohs(bla_dst->group));
        bla_dst_own->group = bla_dst->group;
    }

    batadv_orig_node_free_ref(orig_node);

    return 2;
}


/* @bat_priv: the bat priv with all the soft interface information
 * @skb: the frame to be checked
 *
 * Check if this is a claim frame, and process it accordingly.
 *
 * returns 1 if it was a claim frame, otherwise return 0 to
 * tell the callee that it can use the frame on its own.
 */
static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
                    struct batadv_hard_iface *primary_if,
                    struct sk_buff *skb)
{
    struct ethhdr *ethhdr;
    struct vlan_ethhdr *vhdr;
    struct arphdr *arphdr;
    uint8_t *hw_src, *hw_dst;
    struct batadv_bla_claim_dst *bla_dst;
    uint16_t proto;
    int headlen;
    short vid = -1;
    int ret;

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

    if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
        vhdr = (struct vlan_ethhdr *)ethhdr;
        vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
        proto = ntohs(vhdr->h_vlan_encapsulated_proto);
        headlen = sizeof(*vhdr);
    } else {
        proto = ntohs(ethhdr->h_proto);
        headlen = ETH_HLEN;
    }

    if (proto != ETH_P_ARP)
        return 0; /* not a claim frame */

    /* this must be a ARP frame. check if it is a claim. */

    if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
        return 0;

    /* pskb_may_pull() may have modified the pointers, get ethhdr again */
    ethhdr = (struct ethhdr *)skb_mac_header(skb);
    arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);

    /* Check whether the ARP frame carries a valid
     * IP information
     */
    if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
        return 0;
    if (arphdr->ar_pro != htons(ETH_P_IP))
        return 0;
    if (arphdr->ar_hln != ETH_ALEN)
        return 0;
    if (arphdr->ar_pln != 4)
        return 0;

    hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
    hw_dst = hw_src + ETH_ALEN + 4;
    bla_dst = (struct batadv_bla_claim_dst *)hw_dst;

    /* check if it is a claim frame. */
    ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
                       ethhdr);
    if (ret == 1)
        batadv_dbg(BATADV_DBG_BLA, bat_priv,
               "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
               ethhdr->h_source, vid, hw_src, hw_dst);

    if (ret < 2)
        return ret;

    /* become a backbone gw ourselves on this vlan if not happened yet */
    batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);

    /* check for the different types of claim frames ... */
    switch (bla_dst->type) {
    case BATADV_CLAIM_TYPE_CLAIM:
        if (batadv_handle_claim(bat_priv, primary_if, hw_src,
                    ethhdr->h_source, vid))
            return 1;
        break;
    case BATADV_CLAIM_TYPE_UNCLAIM:
        if (batadv_handle_unclaim(bat_priv, primary_if,
                      ethhdr->h_source, hw_src, vid))
            return 1;
        break;

    case BATADV_CLAIM_TYPE_ANNOUNCE:
        if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
                       vid))
            return 1;
        break;
    case BATADV_CLAIM_TYPE_REQUEST:
        if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
                      vid))
            return 1;
        break;
    }

    batadv_dbg(BATADV_DBG_BLA, bat_priv,
           "bla_process_claim(): ERROR - this looks like a claim frame, but is useless. eth src %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
           ethhdr->h_source, vid, hw_src, hw_dst);
    return 1;
}

/* Check when we last heard from other nodes, and remove them in case of
 * a time out, or clean all backbone gws if now is set.
 */
static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
{
    struct batadv_backbone_gw *backbone_gw;
    struct hlist_node *node, *node_tmp;
    struct hlist_head *head;
    struct batadv_hashtable *hash;
    spinlock_t *list_lock;  /* protects write access to the hash lists */
    int i;

    hash = bat_priv->bla.backbone_hash;
    if (!hash)
        return;

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

        spin_lock_bh(list_lock);
        hlist_for_each_entry_safe(backbone_gw, node, node_tmp,
                      head, hash_entry) {
            if (now)
                goto purge_now;
            if (!batadv_has_timed_out(backbone_gw->lasttime,
                          BATADV_BLA_BACKBONE_TIMEOUT))
                continue;

            batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
                   "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
                   backbone_gw->orig);

purge_now:
            /* don't wait for the pending request anymore */
            if (atomic_read(&backbone_gw->request_sent))
                atomic_dec(&bat_priv->bla.num_requests);

            batadv_bla_del_backbone_claims(backbone_gw);

            hlist_del_rcu(node);
            batadv_backbone_gw_free_ref(backbone_gw);
        }
        spin_unlock_bh(list_lock);
    }
}

static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
                    struct batadv_hard_iface *primary_if,
                    int now)
{
    struct batadv_claim *claim;
    struct hlist_node *node;
    struct hlist_head *head;
    struct batadv_hashtable *hash;
    int i;

    hash = bat_priv->bla.claim_hash;
    if (!hash)
        return;

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

        rcu_read_lock();
        hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
            if (now)
                goto purge_now;
            if (!batadv_compare_eth(claim->backbone_gw->orig,
                        primary_if->net_dev->dev_addr))
                continue;
            if (!batadv_has_timed_out(claim->lasttime,
                          BATADV_BLA_CLAIM_TIMEOUT))
                continue;

            batadv_dbg(BATADV_DBG_BLA, bat_priv,
                   "bla_purge_claims(): %pM, vid %d, time out\n",
                   claim->addr, claim->vid);

purge_now:
            batadv_handle_unclaim(bat_priv, primary_if,
                          claim->backbone_gw->orig,
                          claim->addr, claim->vid);
        }
        rcu_read_unlock();
    }
}

void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
                    struct batadv_hard_iface *primary_if,
                    struct batadv_hard_iface *oldif)
{
    struct batadv_backbone_gw *backbone_gw;
    struct hlist_node *node;
    struct hlist_head *head;
    struct batadv_hashtable *hash;
    __be16 group;
    int i;

    /* reset bridge loop avoidance group id */
    group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
    bat_priv->bla.claim_dest.group = group;

    if (!oldif) {
        batadv_bla_purge_claims(bat_priv, NULL, 1);
        batadv_bla_purge_backbone_gw(bat_priv, 1);
        return;
    }

    hash = bat_priv->bla.backbone_hash;
    if (!hash)
        return;

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

        rcu_read_lock();
        hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
            /* own orig still holds the old value. */
            if (!batadv_compare_eth(backbone_gw->orig,
                        oldif->net_dev->dev_addr))
                continue;

            memcpy(backbone_gw->orig,
                   primary_if->net_dev->dev_addr, ETH_ALEN);
            /* send an announce frame so others will ask for our
             * claims and update their tables.
             */
            batadv_bla_send_announce(bat_priv, backbone_gw);
        }
        rcu_read_unlock();
    }
}



/* (re)start the timer */
static void batadv_bla_start_timer(struct batadv_priv *bat_priv)
{
    INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);
    queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
               msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
}

/* periodic work to do:
 *  * purge structures when they are too old
 *  * send announcements
 */
static void batadv_bla_periodic_work(struct work_struct *work)
{
    struct delayed_work *delayed_work;
    struct batadv_priv *bat_priv;
    struct batadv_priv_bla *priv_bla;
    struct hlist_node *node;
    struct hlist_head *head;
    struct batadv_backbone_gw *backbone_gw;
    struct batadv_hashtable *hash;
    struct batadv_hard_iface *primary_if;
    int i;

    delayed_work = container_of(work, struct delayed_work, work);
    priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
    bat_priv = container_of(priv_bla, struct batadv_priv, bla);
    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (!primary_if)
        goto out;

    batadv_bla_purge_claims(bat_priv, primary_if, 0);
    batadv_bla_purge_backbone_gw(bat_priv, 0);

    if (!atomic_read(&bat_priv->bridge_loop_avoidance))
        goto out;

    hash = bat_priv->bla.backbone_hash;
    if (!hash)
        goto out;

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

        rcu_read_lock();
        hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
            if (!batadv_compare_eth(backbone_gw->orig,
                        primary_if->net_dev->dev_addr))
                continue;

            backbone_gw->lasttime = jiffies;

            batadv_bla_send_announce(bat_priv, backbone_gw);
        }
        rcu_read_unlock();
    }
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);

    batadv_bla_start_timer(bat_priv);
}

/* The hash for claim and backbone hash receive the same key because they
 * are getting initialized by hash_new with the same key. Reinitializing
 * them with to different keys to allow nested locking without generating
 * lockdep warnings
 */
static struct lock_class_key batadv_claim_hash_lock_class_key;
static struct lock_class_key batadv_backbone_hash_lock_class_key;

/* initialize all bla structures */
int batadv_bla_init(struct batadv_priv *bat_priv)
{
    int i;
    uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
    struct batadv_hard_iface *primary_if;
    uint16_t crc;
    unsigned long entrytime;

    spin_lock_init(&bat_priv->bla.bcast_duplist_lock);

    batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");

    /* setting claim destination address */
    memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
    bat_priv->bla.claim_dest.type = 0;
    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (primary_if) {
        crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
        bat_priv->bla.claim_dest.group = htons(crc);
        batadv_hardif_free_ref(primary_if);
    } else {
        bat_priv->bla.claim_dest.group = 0; /* will be set later */
    }

    /* initialize the duplicate list */
    entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
    for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
        bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
    bat_priv->bla.bcast_duplist_curr = 0;

    if (bat_priv->bla.claim_hash)
        return 0;

    bat_priv->bla.claim_hash = batadv_hash_new(128);
    bat_priv->bla.backbone_hash = batadv_hash_new(32);

    if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
        return -ENOMEM;

    batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
                   &batadv_claim_hash_lock_class_key);
    batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
                   &batadv_backbone_hash_lock_class_key);

    batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");

    batadv_bla_start_timer(bat_priv);
    return 0;
}

int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
                   struct batadv_bcast_packet *bcast_packet,
                   int bcast_packet_len)
{
    int i, length, curr, ret = 0;
    uint8_t *content;
    uint16_t crc;
    struct batadv_bcast_duplist_entry *entry;

    length = bcast_packet_len - sizeof(*bcast_packet);
    content = (uint8_t *)bcast_packet;
    content += sizeof(*bcast_packet);

    /* calculate the crc ... */
    crc = crc16(0, content, length);

    spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);

    for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
        curr = (bat_priv->bla.bcast_duplist_curr + i);
        curr %= BATADV_DUPLIST_SIZE;
        entry = &bat_priv->bla.bcast_duplist[curr];

        /* we can stop searching if the entry is too old ;
         * later entries will be even older
         */
        if (batadv_has_timed_out(entry->entrytime,
                     BATADV_DUPLIST_TIMEOUT))
            break;

        if (entry->crc != crc)
            continue;

        if (batadv_compare_eth(entry->orig, bcast_packet->orig))
            continue;

        /* this entry seems to match: same crc, not too old,
         * and from another gw. therefore return 1 to forbid it.
         */
        ret = 1;
        goto out;
    }
    /* not found, add a new entry (overwrite the oldest entry)
     * and allow it, its the first occurence.
     */
    curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
    curr %= BATADV_DUPLIST_SIZE;
    entry = &bat_priv->bla.bcast_duplist[curr];
    entry->crc = crc;
    entry->entrytime = jiffies;
    memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
    bat_priv->bla.bcast_duplist_curr = curr;

out:
    spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);

    return ret;
}



/* @bat_priv: the bat priv with all the soft interface information
 * @orig: originator mac address
 *
 * check if the originator is a gateway for any VLAN ID.
 *
 * returns 1 if it is found, 0 otherwise
 */
int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig)
{
    struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
    struct hlist_head *head;
    struct hlist_node *node;
    struct batadv_backbone_gw *backbone_gw;
    int i;

    if (!atomic_read(&bat_priv->bridge_loop_avoidance))
        return 0;

    if (!hash)
        return 0;

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

        rcu_read_lock();
        hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
            if (batadv_compare_eth(backbone_gw->orig, orig)) {
                rcu_read_unlock();
                return 1;
            }
        }
        rcu_read_unlock();
    }

    return 0;
}


int batadv_bla_is_backbone_gw(struct sk_buff *skb,
                  struct batadv_orig_node *orig_node, int hdr_size)
{
    struct ethhdr *ethhdr;
    struct vlan_ethhdr *vhdr;
    struct batadv_backbone_gw *backbone_gw;
    short vid = -1;

    if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
        return 0;

    /* first, find out the vid. */
    if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
        return 0;

    ethhdr = (struct ethhdr *)(((uint8_t *)skb->data) + hdr_size);

    if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
        if (!pskb_may_pull(skb, hdr_size + sizeof(struct vlan_ethhdr)))
            return 0;

        vhdr = (struct vlan_ethhdr *)(skb->data + hdr_size);
        vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
    }

    /* see if this originator is a backbone gw for this VLAN */
    backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
                        orig_node->orig, vid);
    if (!backbone_gw)
        return 0;

    batadv_backbone_gw_free_ref(backbone_gw);
    return 1;
}

/* free all bla structures (for softinterface free or module unload) */
void batadv_bla_free(struct batadv_priv *bat_priv)
{
    struct batadv_hard_iface *primary_if;

    cancel_delayed_work_sync(&bat_priv->bla.work);
    primary_if = batadv_primary_if_get_selected(bat_priv);

    if (bat_priv->bla.claim_hash) {
        batadv_bla_purge_claims(bat_priv, primary_if, 1);
        batadv_hash_destroy(bat_priv->bla.claim_hash);
        bat_priv->bla.claim_hash = NULL;
    }
    if (bat_priv->bla.backbone_hash) {
        batadv_bla_purge_backbone_gw(bat_priv, 1);
        batadv_hash_destroy(bat_priv->bla.backbone_hash);
        bat_priv->bla.backbone_hash = NULL;
    }
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
}

int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid,
          bool is_bcast)
{
    struct ethhdr *ethhdr;
    struct batadv_claim search_claim, *claim = NULL;
    struct batadv_hard_iface *primary_if;
    int ret;

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

    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (!primary_if)
        goto handled;

    if (!atomic_read(&bat_priv->bridge_loop_avoidance))
        goto allow;


    if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
        /* don't allow broadcasts while requests are in flight */
        if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
            goto handled;

    memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
    search_claim.vid = vid;
    claim = batadv_claim_hash_find(bat_priv, &search_claim);

    if (!claim) {
        /* possible optimization: race for a claim */
        /* No claim exists yet, claim it for us!
         */
        batadv_handle_claim(bat_priv, primary_if,
                    primary_if->net_dev->dev_addr,
                    ethhdr->h_source, vid);
        goto allow;
    }

    /* if it is our own claim ... */
    if (batadv_compare_eth(claim->backbone_gw->orig,
                   primary_if->net_dev->dev_addr)) {
        /* ... allow it in any case */
        claim->lasttime = jiffies;
        goto allow;
    }

    /* if it is a broadcast ... */
    if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
        /* ... drop it. the responsible gateway is in charge.
         *
         * We need to check is_bcast because with the gateway
         * feature, broadcasts (like DHCP requests) may be sent
         * using a unicast packet type.
         */
        goto handled;
    } else {
        /* seems the client considers us as its best gateway.
         * send a claim and update the claim table
         * immediately.
         */
        batadv_handle_claim(bat_priv, primary_if,
                    primary_if->net_dev->dev_addr,
                    ethhdr->h_source, vid);
        goto allow;
    }
allow:
    batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
    ret = 0;
    goto out;

handled:
    kfree_skb(skb);
    ret = 1;

out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
    if (claim)
        batadv_claim_free_ref(claim);
    return ret;
}

int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid)
{
    struct ethhdr *ethhdr;
    struct batadv_claim search_claim, *claim = NULL;
    struct batadv_hard_iface *primary_if;
    int ret = 0;

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

    if (!atomic_read(&bat_priv->bridge_loop_avoidance))
        goto allow;

    /* in VLAN case, the mac header might not be set. */
    skb_reset_mac_header(skb);

    if (batadv_bla_process_claim(bat_priv, primary_if, skb))
        goto handled;

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

    if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
        /* don't allow broadcasts while requests are in flight */
        if (is_multicast_ether_addr(ethhdr->h_dest))
            goto handled;

    memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
    search_claim.vid = vid;

    claim = batadv_claim_hash_find(bat_priv, &search_claim);

    /* if no claim exists, allow it. */
    if (!claim)
        goto allow;

    /* check if we are responsible. */
    if (batadv_compare_eth(claim->backbone_gw->orig,
                   primary_if->net_dev->dev_addr)) {
        /* if yes, the client has roamed and we have
         * to unclaim it.
         */
        batadv_handle_unclaim(bat_priv, primary_if,
                      primary_if->net_dev->dev_addr,
                      ethhdr->h_source, vid);
        goto allow;
    }

    /* check if it is a multicast/broadcast frame */
    if (is_multicast_ether_addr(ethhdr->h_dest)) {
        /* drop it. the responsible gateway has forwarded it into
         * the backbone network.
         */
        goto handled;
    } else {
        /* we must allow it. at least if we are
         * responsible for the DESTINATION.
         */
        goto allow;
    }
allow:
    batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
    ret = 0;
    goto out;
handled:
    ret = 1;
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
    if (claim)
        batadv_claim_free_ref(claim);
    return ret;
}

int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
{
    struct net_device *net_dev = (struct net_device *)seq->private;
    struct batadv_priv *bat_priv = netdev_priv(net_dev);
    struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
    struct batadv_claim *claim;
    struct batadv_hard_iface *primary_if;
    struct hlist_node *node;
    struct hlist_head *head;
    uint32_t i;
    bool is_own;
    int ret = 0;
    uint8_t *primary_addr;

    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (!primary_if) {
        ret = seq_printf(seq,
                 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
                 net_dev->name);
        goto out;
    }

    if (primary_if->if_status != BATADV_IF_ACTIVE) {
        ret = seq_printf(seq,
                 "BATMAN mesh %s disabled - primary interface not active\n",
                 net_dev->name);
        goto out;
    }

    primary_addr = primary_if->net_dev->dev_addr;
    seq_printf(seq,
           "Claims announced for the mesh %s (orig %pM, group id %04x)\n",
           net_dev->name, primary_addr,
           ntohs(bat_priv->bla.claim_dest.group));
    seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-4s)\n",
           "Client", "VID", "Originator", "CRC");
    for (i = 0; i < hash->size; i++) {
        head = &hash->table[i];

        rcu_read_lock();
        hlist_for_each_entry_rcu(claim, node, head, hash_entry) {
            is_own = batadv_compare_eth(claim->backbone_gw->orig,
                            primary_addr);
            seq_printf(seq, " * %pM on % 5d by %pM [%c] (%04x)\n",
                   claim->addr, claim->vid,
                   claim->backbone_gw->orig,
                   (is_own ? 'x' : ' '),
                   claim->backbone_gw->crc);
        }
        rcu_read_unlock();
    }
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
    return ret;
}

int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
{
    struct net_device *net_dev = (struct net_device *)seq->private;
    struct batadv_priv *bat_priv = netdev_priv(net_dev);
    struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
    struct batadv_backbone_gw *backbone_gw;
    struct batadv_hard_iface *primary_if;
    struct hlist_node *node;
    struct hlist_head *head;
    int secs, msecs;
    uint32_t i;
    bool is_own;
    int ret = 0;
    uint8_t *primary_addr;

    primary_if = batadv_primary_if_get_selected(bat_priv);
    if (!primary_if) {
        ret = seq_printf(seq,
                 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
                 net_dev->name);
        goto out;
    }

    if (primary_if->if_status != BATADV_IF_ACTIVE) {
        ret = seq_printf(seq,
                 "BATMAN mesh %s disabled - primary interface not active\n",
                 net_dev->name);
        goto out;
    }

    primary_addr = primary_if->net_dev->dev_addr;
    seq_printf(seq,
           "Backbones announced for the mesh %s (orig %pM, group id %04x)\n",
           net_dev->name, primary_addr,
           ntohs(bat_priv->bla.claim_dest.group));
    seq_printf(seq, "   %-17s    %-5s %-9s (%-4s)\n",
           "Originator", "VID", "last seen", "CRC");
    for (i = 0; i < hash->size; i++) {
        head = &hash->table[i];

        rcu_read_lock();
        hlist_for_each_entry_rcu(backbone_gw, node, head, hash_entry) {
            msecs = jiffies_to_msecs(jiffies -
                         backbone_gw->lasttime);
            secs = msecs / 1000;
            msecs = msecs % 1000;

            is_own = batadv_compare_eth(backbone_gw->orig,
                            primary_addr);
            if (is_own)
                continue;

            seq_printf(seq,
                   " * %pM on % 5d % 4i.%03is (%04x)\n",
                   backbone_gw->orig, backbone_gw->vid,
                   secs, msecs, backbone_gw->crc);
        }
        rcu_read_unlock();
    }
out:
    if (primary_if)
        batadv_hardif_free_ref(primary_if);
    return ret;
}