batman-adv: Fix potential broadcast BLA-duplicate-check race condition

	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 */

				   struct batadv_bcast_packet *bcast_packet,

				   int bcast_packet_len)

{

	int i, length, curr;

	int i, length, curr, ret = 0;

	uint8_t *content;

	uint16_t crc;

	struct batadv_bcast_duplist_entry *entry;

	/* 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;

		/* this entry seems to match: same crc, not too old,

		 * and from another gw. therefore return 1 to forbid it.

		 */

		return 1;

		ret = 1;

		goto out;

	}

	/* not found, add a new entry (overwrite the oldest entry) */

	/* 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];

	memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);

	bat_priv->bla.bcast_duplist_curr = curr;

	/* allow it, its the first occurence. */

	return 0;

out:

	spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);

	return ret;

}

	struct batadv_hashtable *backbone_hash;

	struct batadv_bcast_duplist_entry bcast_duplist[BATADV_DUPLIST_SIZE];

	int bcast_duplist_curr;

	/* protects bcast_duplist and bcast_duplist_curr */

	spinlock_t bcast_duplist_lock;

	struct batadv_bla_claim_dst claim_dest;

	struct delayed_work work;

};