text: /* Copyright (C) 2011-2017  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, see <http://www.gnu.org/licenses/>.
   */
  
  #include "bridge_loop_avoidance.h"
  #include "main.h"
  
  #include <linux/atomic.h>
  #include <linux/byteorder/generic.h>
  #include <linux/compiler.h>
  #include <linux/crc16.h>
  #include <linux/errno.h>
  #include <linux/etherdevice.h>
  #include <linux/fs.h>
  #include <linux/if_arp.h>
  #include <linux/if_ether.h>
  #include <linux/if_vlan.h>
  #include <linux/jhash.h>
  #include <linux/jiffies.h>
  #include <linux/kernel.h>
  #include <linux/kref.h>
  #include <linux/list.h>
  #include <linux/lockdep.h>
  #include <linux/netdevice.h>
  #include <linux/netlink.h>
  #include <linux/rculist.h>
  #include <linux/rcupdate.h>
  #include <linux/seq_file.h>
  #include <linux/skbuff.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/stddef.h>
  #include <linux/string.h>
  #include <linux/workqueue.h>
  #include <net/arp.h>
  #include <net/genetlink.h>
  #include <net/netlink.h>
  #include <net/sock.h>
  #include <uapi/linux/batman_adv.h>
  
  #include "hard-interface.h"
  #include "hash.h"
  #include "log.h"
  #include "netlink.h"
  #include "originator.h"
  #include "packet.h"
  #include "soft-interface.h"
  #include "sysfs.h"
  #include "translation-table.h"
  
  static const u8 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_bla_backbone_gw *backbone_gw);
  
  /**
   * batadv_choose_claim - choose the right bucket for a claim.
   * @data: data to hash
   * @size: size of the hash table
   *
   * Return: the hash index of the claim
   */
  static inline u32 batadv_choose_claim(const void *data, u32 size)
  {
  	struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
  	u32 hash = 0;
  
  	hash = jhash(&claim->addr, sizeof(claim->addr), hash);
  	hash = jhash(&claim->vid, sizeof(claim->vid), hash);
  
  	return hash % size;
  }
  
  /**
   * batadv_choose_backbone_gw - choose the right bucket for a backbone gateway.
   * @data: data to hash
   * @size: size of the hash table
   *
   * Return: the hash index of the backbone gateway
   */
  static inline u32 batadv_choose_backbone_gw(const void *data, u32 size)
  {
  	const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
  	u32 hash = 0;
  
  	hash = jhash(&claim->addr, sizeof(claim->addr), hash);
  	hash = jhash(&claim->vid, sizeof(claim->vid), hash);
  
  	return hash % size;
  }
  
  /**
   * batadv_compare_backbone_gw - compare address and vid of two backbone gws
   * @node: list node of the first entry to compare
   * @data2: pointer to the second backbone gateway
   *
   * Return: true if the backbones have the same data, false otherwise
   */
  static bool batadv_compare_backbone_gw(const struct hlist_node *node,
  				       const void *data2)
  {
  	const void *data1 = container_of(node, struct batadv_bla_backbone_gw,
  					 hash_entry);
  	const struct batadv_bla_backbone_gw *gw1 = data1;
  	const struct batadv_bla_backbone_gw *gw2 = data2;
  
  	if (!batadv_compare_eth(gw1->orig, gw2->orig))
  		return false;
  
  	if (gw1->vid != gw2->vid)
  		return false;
  
  	return true;
  }
  
  /**
   * batadv_compare_claim - compare address and vid of two claims
   * @node: list node of the first entry to compare
   * @data2: pointer to the second claims
   *
   * Return: true if the claim have the same data, 0 otherwise
   */
  static bool batadv_compare_claim(const struct hlist_node *node,
  				 const void *data2)
  {
  	const void *data1 = container_of(node, struct batadv_bla_claim,
  					 hash_entry);
  	const struct batadv_bla_claim *cl1 = data1;
  	const struct batadv_bla_claim *cl2 = data2;
  
  	if (!batadv_compare_eth(cl1->addr, cl2->addr))
  		return false;
  
  	if (cl1->vid != cl2->vid)
  		return false;
  
  	return true;
  }
  
  /**
   * batadv_backbone_gw_release - release backbone gw from lists and queue for
   *  free after rcu grace period
   * @ref: kref pointer of the backbone gw
   */
  static void batadv_backbone_gw_release(struct kref *ref)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  
  	backbone_gw = container_of(ref, struct batadv_bla_backbone_gw,
  				   refcount);
  
  	kfree_rcu(backbone_gw, rcu);
  }
  
  /**
   * batadv_backbone_gw_put - decrement the backbone gw refcounter and possibly
   *  release it
   * @backbone_gw: backbone gateway to be free'd
   */
  static void batadv_backbone_gw_put(struct batadv_bla_backbone_gw *backbone_gw)
  {
  	kref_put(&backbone_gw->refcount, batadv_backbone_gw_release);
  }
  
  /**
   * batadv_claim_release - release claim from lists and queue for free after rcu
   *  grace period
   * @ref: kref pointer of the claim
   */
  static void batadv_claim_release(struct kref *ref)
  {
  	struct batadv_bla_claim *claim;
  	struct batadv_bla_backbone_gw *old_backbone_gw;
  
  	claim = container_of(ref, struct batadv_bla_claim, refcount);
  
  	spin_lock_bh(&claim->backbone_lock);
  	old_backbone_gw = claim->backbone_gw;
  	claim->backbone_gw = NULL;
  	spin_unlock_bh(&claim->backbone_lock);
  
  	spin_lock_bh(&old_backbone_gw->crc_lock);
  	old_backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
  	spin_unlock_bh(&old_backbone_gw->crc_lock);
  
  	batadv_backbone_gw_put(old_backbone_gw);
  
  	kfree_rcu(claim, rcu);
  }
  
  /**
   * batadv_claim_put - decrement the claim refcounter and possibly
   *  release it
   * @claim: claim to be free'd
   */
  static void batadv_claim_put(struct batadv_bla_claim *claim)
  {
  	kref_put(&claim->refcount, batadv_claim_release);
  }
  
  /**
   * batadv_claim_hash_find - looks for a claim in the claim hash
   * @bat_priv: the bat priv with all the soft interface information
   * @data: search data (may be local/static data)
   *
   * Return: claim if found or NULL otherwise.
   */
  static struct batadv_bla_claim *
  batadv_claim_hash_find(struct batadv_priv *bat_priv,
  		       struct batadv_bla_claim *data)
  {
  	struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
  	struct hlist_head *head;
  	struct batadv_bla_claim *claim;
  	struct batadv_bla_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, head, hash_entry) {
  		if (!batadv_compare_claim(&claim->hash_entry, data))
  			continue;
  
  		if (!kref_get_unless_zero(&claim->refcount))
  			continue;
  
  		claim_tmp = claim;
  		break;
  	}
  	rcu_read_unlock();
  
  	return claim_tmp;
  }
  
  /**
   * batadv_backbone_hash_find - looks for a backbone gateway in the hash
   * @bat_priv: the bat priv with all the soft interface information
   * @addr: the address of the originator
   * @vid: the VLAN ID
   *
   * Return: backbone gateway if found or NULL otherwise
   */
  static struct batadv_bla_backbone_gw *
  batadv_backbone_hash_find(struct batadv_priv *bat_priv, u8 *addr,
  			  unsigned short vid)
  {
  	struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
  	struct hlist_head *head;
  	struct batadv_bla_backbone_gw search_entry, *backbone_gw;
  	struct batadv_bla_backbone_gw *backbone_gw_tmp = NULL;
  	int index;
  
  	if (!hash)
  		return NULL;
  
  	ether_addr_copy(search_entry.orig, addr);
  	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, head, hash_entry) {
  		if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
  						&search_entry))
  			continue;
  
  		if (!kref_get_unless_zero(&backbone_gw->refcount))
  			continue;
  
  		backbone_gw_tmp = backbone_gw;
  		break;
  	}
  	rcu_read_unlock();
  
  	return backbone_gw_tmp;
  }
  
  /**
   * batadv_bla_del_backbone_claims - delete all claims for a backbone
   * @backbone_gw: backbone gateway where the claims should be removed
   */
  static void
  batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
  {
  	struct batadv_hashtable *hash;
  	struct hlist_node *node_tmp;
  	struct hlist_head *head;
  	struct batadv_bla_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_tmp,
  					  head, hash_entry) {
  			if (claim->backbone_gw != backbone_gw)
  				continue;
  
  			batadv_claim_put(claim);
  			hlist_del_rcu(&claim->hash_entry);
  		}
  		spin_unlock_bh(list_lock);
  	}
  
  	/* all claims gone, initialize CRC */
  	spin_lock_bh(&backbone_gw->crc_lock);
  	backbone_gw->crc = BATADV_BLA_CRC_INIT;
  	spin_unlock_bh(&backbone_gw->crc_lock);
  }
  
  /**
   * batadv_bla_send_claim - sends a claim frame according to the provided info
   * @bat_priv: the bat priv with all the soft interface information
   * @mac: the mac address to be announced within the claim
   * @vid: the VLAN ID
   * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
   */
  static void batadv_bla_send_claim(struct batadv_priv *bat_priv, u8 *mac,
  				  unsigned short vid, int claimtype)
  {
  	struct sk_buff *skb;
  	struct ethhdr *ethhdr;
  	struct batadv_hard_iface *primary_if;
  	struct net_device *soft_iface;
  	u8 *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
  			  */
  			 (u8 *)&local_claim_dest);
  
  	if (!skb)
  		goto out;
  
  	ethhdr = (struct ethhdr *)skb->data;
  	hw_src = (u8 *)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
  		 */
  		ether_addr_copy(ethhdr->h_source, mac);
  		batadv_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): CLAIM %pM on vid %d\n", __func__, mac,
  			   batadv_print_vid(vid));
  		break;
  	case BATADV_CLAIM_TYPE_UNCLAIM:
  		/* unclaim frame
  		 * set HW SRC to the clients mac
  		 */
  		ether_addr_copy(hw_src, mac);
  		batadv_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): UNCLAIM %pM on vid %d\n", __func__, mac,
  			   batadv_print_vid(vid));
  		break;
  	case BATADV_CLAIM_TYPE_ANNOUNCE:
  		/* announcement frame
  		 * set HW SRC to the special mac containg the crc
  		 */
  		ether_addr_copy(hw_src, mac);
  		batadv_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): ANNOUNCE of %pM on vid %d\n", __func__,
  			   ethhdr->h_source, batadv_print_vid(vid));
  		break;
  	case BATADV_CLAIM_TYPE_REQUEST:
  		/* request frame
  		 * set HW SRC and header destination to the receiving backbone
  		 * gws mac
  		 */
  		ether_addr_copy(hw_src, mac);
  		ether_addr_copy(ethhdr->h_dest, mac);
  		batadv_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): REQUEST of %pM to %pM on vid %d\n", __func__,
  			   ethhdr->h_source, ethhdr->h_dest,
  			   batadv_print_vid(vid));
  		break;
  	case BATADV_CLAIM_TYPE_LOOPDETECT:
  		ether_addr_copy(ethhdr->h_source, mac);
  		batadv_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): LOOPDETECT of %pM to %pM on vid %d\n",
  			   __func__, ethhdr->h_source, ethhdr->h_dest,
  			   batadv_print_vid(vid));
  
  		break;
  	}
  
  	if (vid & BATADV_VLAN_HAS_TAG) {
  		skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
  				      vid & VLAN_VID_MASK);
  		if (!skb)
  			goto out;
  	}
  
  	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);
  
  	netif_rx(skb);
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  }
  
  /**
   * batadv_bla_loopdetect_report - worker for reporting the loop
   * @work: work queue item
   *
   * Throws an uevent, as the loopdetect check function can't do that itself
   * since the kernel may sleep while throwing uevents.
   */
  static void batadv_bla_loopdetect_report(struct work_struct *work)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	struct batadv_priv *bat_priv;
  	char vid_str[6] = { '\0' };
  
  	backbone_gw = container_of(work, struct batadv_bla_backbone_gw,
  				   report_work);
  	bat_priv = backbone_gw->bat_priv;
  
  	batadv_info(bat_priv->soft_iface,
  		    "Possible loop on VLAN %d detected which can't be handled by BLA - please check your network setup!\n",
  		    batadv_print_vid(backbone_gw->vid));
  	snprintf(vid_str, sizeof(vid_str), "%d",
  		 batadv_print_vid(backbone_gw->vid));
  	vid_str[sizeof(vid_str) - 1] = 0;
  
  	batadv_throw_uevent(bat_priv, BATADV_UEV_BLA, BATADV_UEV_LOOPDETECT,
  			    vid_str);
  
  	batadv_backbone_gw_put(backbone_gw);
  }
  
  /**
   * batadv_bla_get_backbone_gw - finds or creates a backbone gateway
   * @bat_priv: the bat priv with all the soft interface information
   * @orig: the mac address of the originator
   * @vid: the VLAN ID
   * @own_backbone: set if the requested backbone is local
   *
   * Return: the (possibly created) backbone gateway or NULL on error
   */
  static struct batadv_bla_backbone_gw *
  batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, u8 *orig,
  			   unsigned short vid, bool own_backbone)
  {
  	struct batadv_bla_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,
  		   "%s(): not found (%pM, %d), creating new entry\n", __func__,
  		   orig, batadv_print_vid(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;
  	spin_lock_init(&entry->crc_lock);
  	atomic_set(&entry->request_sent, 0);
  	atomic_set(&entry->wait_periods, 0);
  	ether_addr_copy(entry->orig, orig);
  	INIT_WORK(&entry->report_work, batadv_bla_loopdetect_report);
  	kref_init(&entry->refcount);
  
  	kref_get(&entry->refcount);
  	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 entry on this VLAN */
  	orig_node = batadv_orig_hash_find(bat_priv, orig);
  	if (orig_node) {
  		batadv_tt_global_del_orig(bat_priv, orig_node, vid,
  					  "became a backbone gateway");
  		batadv_orig_node_put(orig_node);
  	}
  
  	if (own_backbone) {
  		batadv_bla_send_announce(bat_priv, entry);
  
  		/* this will be decreased in the worker thread */
  		atomic_inc(&entry->request_sent);
  		atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
  		atomic_inc(&bat_priv->bla.num_requests);
  	}
  
  	return entry;
  }
  
  /**
   * batadv_bla_update_own_backbone_gw - updates the own backbone gw for a VLAN
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the selected primary interface
   * @vid: VLAN identifier
   *
   * 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,
  				  unsigned short vid)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  
  	backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
  						 primary_if->net_dev->dev_addr,
  						 vid, true);
  	if (unlikely(!backbone_gw))
  		return;
  
  	backbone_gw->lasttime = jiffies;
  	batadv_backbone_gw_put(backbone_gw);
  }
  
  /**
   * batadv_bla_answer_request - answer a bla request by sending own claims
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: interface where the request came on
   * @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,
  				      unsigned short vid)
  {
  	struct hlist_head *head;
  	struct batadv_hashtable *hash;
  	struct batadv_bla_claim *claim;
  	struct batadv_bla_backbone_gw *backbone_gw;
  	int i;
  
  	batadv_dbg(BATADV_DBG_BLA, bat_priv,
  		   "%s(): received a claim request, send all of our own claims again\n",
  		   __func__);
  
  	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, 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_put(backbone_gw);
  }
  
  /**
   * batadv_bla_send_request - send a request to repeat claims
   * @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_bla_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);
  	}
  }
  
  /**
   * batadv_bla_send_announce - Send an announcement frame
   * @bat_priv: the bat priv with all the soft interface information
   * @backbone_gw: our backbone gateway which should be announced
   */
  static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
  				     struct batadv_bla_backbone_gw *backbone_gw)
  {
  	u8 mac[ETH_ALEN];
  	__be16 crc;
  
  	memcpy(mac, batadv_announce_mac, 4);
  	spin_lock_bh(&backbone_gw->crc_lock);
  	crc = htons(backbone_gw->crc);
  	spin_unlock_bh(&backbone_gw->crc_lock);
  	memcpy(&mac[4], &crc, 2);
  
  	batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
  			      BATADV_CLAIM_TYPE_ANNOUNCE);
  }
  
  /**
   * batadv_bla_add_claim - Adds a claim in the claim hash
   * @bat_priv: the bat priv with all the soft interface information
   * @mac: the mac address of the claim
   * @vid: the VLAN ID of the frame
   * @backbone_gw: the backbone gateway which claims it
   */
  static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
  				 const u8 *mac, const unsigned short vid,
  				 struct batadv_bla_backbone_gw *backbone_gw)
  {
  	struct batadv_bla_backbone_gw *old_backbone_gw;
  	struct batadv_bla_claim *claim;
  	struct batadv_bla_claim search_claim;
  	bool remove_crc = false;
  	int hash_added;
  
  	ether_addr_copy(search_claim.addr, mac);
  	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;
  
  		ether_addr_copy(claim->addr, mac);
  		spin_lock_init(&claim->backbone_lock);
  		claim->vid = vid;
  		claim->lasttime = jiffies;
  		kref_get(&backbone_gw->refcount);
  		claim->backbone_gw = backbone_gw;
  		kref_init(&claim->refcount);
  
  		batadv_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): adding new entry %pM, vid %d to hash ...\n",
  			   __func__, mac, batadv_print_vid(vid));
  
  		kref_get(&claim->refcount);
  		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,
  			   "%s(): changing ownership for %pM, vid %d to gw %pM\n",
  			   __func__, mac, batadv_print_vid(vid),
  			   backbone_gw->orig);
  
  		remove_crc = true;
  	}
  
  	/* replace backbone_gw atomically and adjust reference counters */
  	spin_lock_bh(&claim->backbone_lock);
  	old_backbone_gw = claim->backbone_gw;
  	kref_get(&backbone_gw->refcount);
  	claim->backbone_gw = backbone_gw;
  	spin_unlock_bh(&claim->backbone_lock);
  
  	if (remove_crc) {
  		/* remove claim address from old backbone_gw */
  		spin_lock_bh(&old_backbone_gw->crc_lock);
  		old_backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
  		spin_unlock_bh(&old_backbone_gw->crc_lock);
  	}
  
  	batadv_backbone_gw_put(old_backbone_gw);
  
  	/* add claim address to new backbone_gw */
  	spin_lock_bh(&backbone_gw->crc_lock);
  	backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
  	spin_unlock_bh(&backbone_gw->crc_lock);
  	backbone_gw->lasttime = jiffies;
  
  claim_free_ref:
  	batadv_claim_put(claim);
  }
  
  /**
   * batadv_bla_claim_get_backbone_gw - Get valid reference for backbone_gw of
   *  claim
   * @claim: claim whose backbone_gw should be returned
   *
   * Return: valid reference to claim::backbone_gw
   */
  static struct batadv_bla_backbone_gw *
  batadv_bla_claim_get_backbone_gw(struct batadv_bla_claim *claim)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  
  	spin_lock_bh(&claim->backbone_lock);
  	backbone_gw = claim->backbone_gw;
  	kref_get(&backbone_gw->refcount);
  	spin_unlock_bh(&claim->backbone_lock);
  
  	return backbone_gw;
  }
  
  /**
   * batadv_bla_del_claim - delete a claim from the claim hash
   * @bat_priv: the bat priv with all the soft interface information
   * @mac: mac address of the claim to be removed
   * @vid: VLAN id for the claim to be removed
   */
  static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
  				 const u8 *mac, const unsigned short vid)
  {
  	struct batadv_bla_claim search_claim, *claim;
  
  	ether_addr_copy(search_claim.addr, mac);
  	search_claim.vid = vid;
  	claim = batadv_claim_hash_find(bat_priv, &search_claim);
  	if (!claim)
  		return;
  
  	batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): %pM, vid %d\n", __func__,
  		   mac, batadv_print_vid(vid));
  
  	batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
  			   batadv_choose_claim, claim);
  	batadv_claim_put(claim); /* reference from the hash is gone */
  
  	/* don't need the reference from hash_find() anymore */
  	batadv_claim_put(claim);
  }
  
  /**
   * batadv_handle_announce - check for ANNOUNCE frame
   * @bat_priv: the bat priv with all the soft interface information
   * @an_addr: announcement mac address (ARP Sender HW address)
   * @backbone_addr: originator address of the sender (Ethernet source MAC)
   * @vid: the VLAN ID of the frame
   *
   * Return: true if handled
   */
  static bool batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr,
  				   u8 *backbone_addr, unsigned short vid)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	u16 backbone_crc, crc;
  
  	if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
  		return false;
  
  	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
  						 false);
  
  	if (unlikely(!backbone_gw))
  		return true;
  
  	/* handle as ANNOUNCE frame */
  	backbone_gw->lasttime = jiffies;
  	crc = ntohs(*((__be16 *)(&an_addr[4])));
  
  	batadv_dbg(BATADV_DBG_BLA, bat_priv,
  		   "%s(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
  		   __func__, batadv_print_vid(vid), backbone_gw->orig, crc);
  
  	spin_lock_bh(&backbone_gw->crc_lock);
  	backbone_crc = backbone_gw->crc;
  	spin_unlock_bh(&backbone_gw->crc_lock);
  
  	if (backbone_crc != crc) {
  		batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
  			   "%s(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
  			   __func__, backbone_gw->orig,
  			   batadv_print_vid(backbone_gw->vid),
  			   backbone_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_put(backbone_gw);
  	return true;
  }
  
  /**
   * batadv_handle_request - check for REQUEST frame
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the primary hard interface of this batman soft interface
   * @backbone_addr: backbone address to be requested (ARP sender HW MAC)
   * @ethhdr: ethernet header of a packet
   * @vid: the VLAN ID of the frame
   *
   * Return: true if handled
   */
  static bool batadv_handle_request(struct batadv_priv *bat_priv,
  				  struct batadv_hard_iface *primary_if,
  				  u8 *backbone_addr, struct ethhdr *ethhdr,
  				  unsigned short vid)
  {
  	/* check for REQUEST frame */
  	if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
  		return false;
  
  	/* 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 true;
  
  	batadv_dbg(BATADV_DBG_BLA, bat_priv,
  		   "%s(): REQUEST vid %d (sent by %pM)...\n",
  		   __func__, batadv_print_vid(vid), ethhdr->h_source);
  
  	batadv_bla_answer_request(bat_priv, primary_if, vid);
  	return true;
  }
  
  /**
   * batadv_handle_unclaim - check for UNCLAIM frame
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the primary hard interface of this batman soft interface
   * @backbone_addr: originator address of the backbone (Ethernet source)
   * @claim_addr: Client to be unclaimed (ARP sender HW MAC)
   * @vid: the VLAN ID of the frame
   *
   * Return: true if handled
   */
  static bool batadv_handle_unclaim(struct batadv_priv *bat_priv,
  				  struct batadv_hard_iface *primary_if,
  				  u8 *backbone_addr, u8 *claim_addr,
  				  unsigned short vid)
  {
  	struct batadv_bla_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 true;
  
  	/* this must be an UNCLAIM frame */
  	batadv_dbg(BATADV_DBG_BLA, bat_priv,
  		   "%s(): UNCLAIM %pM on vid %d (sent by %pM)...\n", __func__,
  		   claim_addr, batadv_print_vid(vid), backbone_gw->orig);
  
  	batadv_bla_del_claim(bat_priv, claim_addr, vid);
  	batadv_backbone_gw_put(backbone_gw);
  	return true;
  }
  
  /**
   * batadv_handle_claim - check for CLAIM frame
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the primary hard interface of this batman soft interface
   * @backbone_addr: originator address of the backbone (Ethernet Source)
   * @claim_addr: client mac address to be claimed (ARP sender HW MAC)
   * @vid: the VLAN ID of the frame
   *
   * Return: true if handled
   */
  static bool batadv_handle_claim(struct batadv_priv *bat_priv,
  				struct batadv_hard_iface *primary_if,
  				u8 *backbone_addr, u8 *claim_addr,
  				unsigned short vid)
  {
  	struct batadv_bla_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,
  						 false);
  
  	if (unlikely(!backbone_gw))
  		return true;
  
  	/* 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_put(backbone_gw);
  	return true;
  }
  
  /**
   * batadv_check_claim_group - check for claim group membership
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the primary interface of this batman interface
   * @hw_src: the Hardware source in the ARP Header
   * @hw_dst: the Hardware destination in the ARP Header
   * @ethhdr: pointer to the Ethernet header of the claim frame
   *
   * checks if it is a claim packet and if its on the same group.
   * This function also applies the group ID of the sender
   * if it is in the same mesh.
   *
   * Return:
   *	2  - if it is a claim packet and on the same group
   *	1  - if is a claim packet from another group
   *	0  - if it is not a claim packet
   */
  static int batadv_check_claim_group(struct batadv_priv *bat_priv,
  				    struct batadv_hard_iface *primary_if,
  				    u8 *hw_src, u8 *hw_dst,
  				    struct ethhdr *ethhdr)
  {
  	u8 *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;
  
  	/* 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: %#.4x\n",
  			   ntohs(bla_dst->group));
  		bla_dst_own->group = bla_dst->group;
  	}
  
  	batadv_orig_node_put(orig_node);
  
  	return 2;
  }
  
  /**
   * batadv_bla_process_claim - Check if this is a claim frame, and process it
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the primary hard interface of this batman soft interface
   * @skb: the frame to be checked
   *
   * Return: true if it was a claim frame, otherwise return false to
   * tell the callee that it can use the frame on its own.
   */
  static bool batadv_bla_process_claim(struct batadv_priv *bat_priv,
  				     struct batadv_hard_iface *primary_if,
  				     struct sk_buff *skb)
  {
  	struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;
  	u8 *hw_src, *hw_dst;
  	struct vlan_hdr *vhdr, vhdr_buf;
  	struct ethhdr *ethhdr;
  	struct arphdr *arphdr;
  	unsigned short vid;
  	int vlan_depth = 0;
  	__be16 proto;
  	int headlen;
  	int ret;
  
  	vid = batadv_get_vid(skb, 0);
  	ethhdr = eth_hdr(skb);
  
  	proto = ethhdr->h_proto;
  	headlen = ETH_HLEN;
  	if (vid & BATADV_VLAN_HAS_TAG) {
  		/* Traverse the VLAN/Ethertypes.
  		 *
  		 * At this point it is known that the first protocol is a VLAN
  		 * header, so start checking at the encapsulated protocol.
  		 *
  		 * The depth of the VLAN headers is recorded to drop BLA claim
  		 * frames encapsulated into multiple VLAN headers (QinQ).
  		 */
  		do {
  			vhdr = skb_header_pointer(skb, headlen, VLAN_HLEN,
  						  &vhdr_buf);
  			if (!vhdr)
  				return false;
  
  			proto = vhdr->h_vlan_encapsulated_proto;
  			headlen += VLAN_HLEN;
  			vlan_depth++;
  		} while (proto == htons(ETH_P_8021Q));
  	}
  
  	if (proto != htons(ETH_P_ARP))
  		return false; /* 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 false;
  
  	/* pskb_may_pull() may have modified the pointers, get ethhdr again */
  	ethhdr = eth_hdr(skb);
  	arphdr = (struct arphdr *)((u8 *)ethhdr + headlen);
  
  	/* Check whether the ARP frame carries a valid
  	 * IP information
  	 */
  	if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
  		return false;
  	if (arphdr->ar_pro != htons(ETH_P_IP))
  		return false;
  	if (arphdr->ar_hln != ETH_ALEN)
  		return false;
  	if (arphdr->ar_pln != 4)
  		return false;
  
  	hw_src = (u8 *)arphdr + sizeof(struct arphdr);
  	hw_dst = hw_src + ETH_ALEN + 4;
  	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
  	bla_dst_own = &bat_priv->bla.claim_dest;
  
  	/* check if it is a claim frame in general */
  	if (memcmp(bla_dst->magic, bla_dst_own->magic,
  		   sizeof(bla_dst->magic)) != 0)
  		return false;
  
  	/* check if there is a claim frame encapsulated deeper in (QinQ) and
  	 * drop that, as this is not supported by BLA but should also not be
  	 * sent via the mesh.
  	 */
  	if (vlan_depth > 1)
  		return true;
  
  	/* Let the loopdetect frames on the mesh in any case. */
  	if (bla_dst->type == BATADV_CLAIM_TYPE_LOOPDETECT)
  		return false;
  
  	/* 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,
  			   "%s(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
  			   __func__, ethhdr->h_source, batadv_print_vid(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 true;
  		break;
  	case BATADV_CLAIM_TYPE_UNCLAIM:
  		if (batadv_handle_unclaim(bat_priv, primary_if,
  					  ethhdr->h_source, hw_src, vid))
  			return true;
  		break;
  
  	case BATADV_CLAIM_TYPE_ANNOUNCE:
  		if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
  					   vid))
  			return true;
  		break;
  	case BATADV_CLAIM_TYPE_REQUEST:
  		if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
  					  vid))
  			return true;
  		break;
  	}
  
  	batadv_dbg(BATADV_DBG_BLA, bat_priv,
  		   "%s(): ERROR - this looks like a claim frame, but is useless. eth src %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
  		   __func__, ethhdr->h_source, batadv_print_vid(vid), hw_src,
  		   hw_dst);
  	return true;
  }
  
  /**
   * batadv_bla_purge_backbone_gw - Remove backbone gateways after a timeout or
   *  immediately
   * @bat_priv: the bat priv with all the soft interface information
   * @now: whether the whole hash shall be wiped now
   *
   * 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_bla_backbone_gw *backbone_gw;
  	struct hlist_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_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,
  				   "%s(): backbone gw %pM timed out\n",
  				   __func__, 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(&backbone_gw->hash_entry);
  			batadv_backbone_gw_put(backbone_gw);
  		}
  		spin_unlock_bh(list_lock);
  	}
  }
  
  /**
   * batadv_bla_purge_claims - Remove claims after a timeout or immediately
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the selected primary interface, may be NULL if now is set
   * @now: whether the whole hash shall be wiped now
   *
   * Check when we heard last time from our own claims, and remove them in case of
   * a time out, or clean all claims if now is set
   */
  static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
  				    struct batadv_hard_iface *primary_if,
  				    int now)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	struct batadv_bla_claim *claim;
  	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, head, hash_entry) {
  			backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
  			if (now)
  				goto purge_now;
  
  			if (!batadv_compare_eth(backbone_gw->orig,
  						primary_if->net_dev->dev_addr))
  				goto skip;
  
  			if (!batadv_has_timed_out(claim->lasttime,
  						  BATADV_BLA_CLAIM_TIMEOUT))
  				goto skip;
  
  			batadv_dbg(BATADV_DBG_BLA, bat_priv,
  				   "%s(): timed out.\n", __func__);
  
  purge_now:
  			batadv_dbg(BATADV_DBG_BLA, bat_priv,
  				   "%s(): %pM, vid %d\n", __func__,
  				   claim->addr, claim->vid);
  
  			batadv_handle_unclaim(bat_priv, primary_if,
  					      backbone_gw->orig,
  					      claim->addr, claim->vid);
  skip:
  			batadv_backbone_gw_put(backbone_gw);
  		}
  		rcu_read_unlock();
  	}
  }
  
  /**
   * batadv_bla_update_orig_address - Update the backbone gateways when the own
   *  originator address changes
   * @bat_priv: the bat priv with all the soft interface information
   * @primary_if: the new selected primary_if
   * @oldif: the old primary interface, may be NULL
   */
  void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
  				    struct batadv_hard_iface *primary_if,
  				    struct batadv_hard_iface *oldif)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	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;
  
  	/* purge everything when bridge loop avoidance is turned off */
  	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
  		oldif = NULL;
  
  	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, head, hash_entry) {
  			/* own orig still holds the old value. */
  			if (!batadv_compare_eth(backbone_gw->orig,
  						oldif->net_dev->dev_addr))
  				continue;
  
  			ether_addr_copy(backbone_gw->orig,
  					primary_if->net_dev->dev_addr);
  			/* 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();
  	}
  }
  
  /**
   * batadv_bla_send_loopdetect - send a loopdetect frame
   * @bat_priv: the bat priv with all the soft interface information
   * @backbone_gw: the backbone gateway for which a loop should be detected
   *
   * To detect loops that the bridge loop avoidance can't handle, send a loop
   * detection packet on the backbone. Unlike other BLA frames, this frame will
   * be allowed on the mesh by other nodes. If it is received on the mesh, this
   * indicates that there is a loop.
   */
  static void
  batadv_bla_send_loopdetect(struct batadv_priv *bat_priv,
  			   struct batadv_bla_backbone_gw *backbone_gw)
  {
  	batadv_dbg(BATADV_DBG_BLA, bat_priv, "Send loopdetect frame for vid %d\n",
  		   backbone_gw->vid);
  	batadv_bla_send_claim(bat_priv, bat_priv->bla.loopdetect_addr,
  			      backbone_gw->vid, BATADV_CLAIM_TYPE_LOOPDETECT);
  }
  
  /**
   * batadv_bla_status_update - purge bla interfaces if necessary
   * @net_dev: the soft interface net device
   */
  void batadv_bla_status_update(struct net_device *net_dev)
  {
  	struct batadv_priv *bat_priv = netdev_priv(net_dev);
  	struct batadv_hard_iface *primary_if;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  	if (!primary_if)
  		return;
  
  	/* this function already purges everything when bla is disabled,
  	 * so just call that one.
  	 */
  	batadv_bla_update_orig_address(bat_priv, primary_if, primary_if);
  	batadv_hardif_put(primary_if);
  }
  
  /**
   * batadv_bla_periodic_work - performs periodic bla work
   * @work: kernel work struct
   *
   * 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_head *head;
  	struct batadv_bla_backbone_gw *backbone_gw;
  	struct batadv_hashtable *hash;
  	struct batadv_hard_iface *primary_if;
  	bool send_loopdetect = false;
  	int i;
  
  	delayed_work = to_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;
  
  	if (atomic_dec_and_test(&bat_priv->bla.loopdetect_next)) {
  		/* set a new random mac address for the next bridge loop
  		 * detection frames. Set the locally administered bit to avoid
  		 * collisions with users mac addresses.
  		 */
  		random_ether_addr(bat_priv->bla.loopdetect_addr);
  		bat_priv->bla.loopdetect_addr[0] = 0xba;
  		bat_priv->bla.loopdetect_addr[1] = 0xbe;
  		bat_priv->bla.loopdetect_lasttime = jiffies;
  		atomic_set(&bat_priv->bla.loopdetect_next,
  			   BATADV_BLA_LOOPDETECT_PERIODS);
  
  		/* mark for sending loop detect on all VLANs */
  		send_loopdetect = true;
  	}
  
  	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, 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);
  			if (send_loopdetect)
  				batadv_bla_send_loopdetect(bat_priv,
  							   backbone_gw);
  
  			/* request_sent is only set after creation to avoid
  			 * problems when we are not yet known as backbone gw
  			 * in the backbone.
  			 *
  			 * We can reset this now after we waited some periods
  			 * to give bridge forward delays and bla group forming
  			 * some grace time.
  			 */
  
  			if (atomic_read(&backbone_gw->request_sent) == 0)
  				continue;
  
  			if (!atomic_dec_and_test(&backbone_gw->wait_periods))
  				continue;
  
  			atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
  			atomic_set(&backbone_gw->request_sent, 0);
  		}
  		rcu_read_unlock();
  	}
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  
  	queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
  			   msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
  }
  
  /* 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;
  
  /**
   * batadv_bla_init - initialize all bla structures
   * @bat_priv: the bat priv with all the soft interface information
   *
   * Return: 0 on success, < 0 on error.
   */
  int batadv_bla_init(struct batadv_priv *bat_priv)
  {
  	int i;
  	u8 claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
  	struct batadv_hard_iface *primary_if;
  	u16 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_put(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;
  
  	atomic_set(&bat_priv->bla.loopdetect_next,
  		   BATADV_BLA_LOOPDETECT_PERIODS);
  
  	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");
  
  	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));
  	return 0;
  }
  
  /**
   * batadv_bla_check_bcast_duplist - Check if a frame is in the broadcast dup.
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: contains the bcast_packet to be checked
   *
   * check if it is on our broadcast list. Another gateway might
   * have sent the same packet because it is connected to the same backbone,
   * so we have to remove this duplicate.
   *
   * This is performed by checking the CRC, which will tell us
   * with a good chance that it is the same packet. If it is furthermore
   * sent by another host, drop it. We allow equal packets from
   * the same host however as this might be intended.
   *
   * Return: true if a packet is in the duplicate list, false otherwise.
   */
  bool batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
  				    struct sk_buff *skb)
  {
  	int i, curr;
  	__be32 crc;
  	struct batadv_bcast_packet *bcast_packet;
  	struct batadv_bcast_duplist_entry *entry;
  	bool ret = false;
  
  	bcast_packet = (struct batadv_bcast_packet *)skb->data;
  
  	/* calculate the crc ... */
  	crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));
  
  	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 true to forbid it.
  		 */
  		ret = true;
  		goto out;
  	}
  	/* not found, add a new entry (overwrite the oldest entry)
  	 * and allow it, its the first occurrence.
  	 */
  	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;
  	ether_addr_copy(entry->orig, bcast_packet->orig);
  	bat_priv->bla.bcast_duplist_curr = curr;
  
  out:
  	spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
  
  	return ret;
  }
  
  /**
   * batadv_bla_is_backbone_gw_orig - Check if the originator is a gateway for
   *  the VLAN identified by vid.
   * @bat_priv: the bat priv with all the soft interface information
   * @orig: originator mac address
   * @vid: VLAN identifier
   *
   * Return: true if orig is a backbone for this vid, false otherwise.
   */
  bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, u8 *orig,
  				    unsigned short vid)
  {
  	struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
  	struct hlist_head *head;
  	struct batadv_bla_backbone_gw *backbone_gw;
  	int i;
  
  	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
  		return false;
  
  	if (!hash)
  		return false;
  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];
  
  		rcu_read_lock();
  		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
  			if (batadv_compare_eth(backbone_gw->orig, orig) &&
  			    backbone_gw->vid == vid) {
  				rcu_read_unlock();
  				return true;
  			}
  		}
  		rcu_read_unlock();
  	}
  
  	return false;
  }
  
  /**
   * batadv_bla_is_backbone_gw - check if originator is a backbone gw for a VLAN.
   * @skb: the frame to be checked
   * @orig_node: the orig_node of the frame
   * @hdr_size: maximum length of the frame
   *
   * Return: true if the orig_node is also a gateway on the soft interface,
   * otherwise it returns false.
   */
  bool batadv_bla_is_backbone_gw(struct sk_buff *skb,
  			       struct batadv_orig_node *orig_node, int hdr_size)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	unsigned short vid;
  
  	if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
  		return false;
  
  	/* first, find out the vid. */
  	if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
  		return false;
  
  	vid = batadv_get_vid(skb, hdr_size);
  
  	/* 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 false;
  
  	batadv_backbone_gw_put(backbone_gw);
  	return true;
  }
  
  /**
   * batadv_bla_free - free all bla structures
   * @bat_priv: the bat priv with all the soft interface information
   *
   * 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_put(primary_if);
  }
  
  /**
   * batadv_bla_loopdetect_check - check and handle a detected loop
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: the packet to check
   * @primary_if: interface where the request came on
   * @vid: the VLAN ID of the frame
   *
   * Checks if this packet is a loop detect frame which has been sent by us,
   * throw an uevent and log the event if that is the case.
   *
   * Return: true if it is a loop detect frame which is to be dropped, false
   * otherwise.
   */
  static bool
  batadv_bla_loopdetect_check(struct batadv_priv *bat_priv, struct sk_buff *skb,
  			    struct batadv_hard_iface *primary_if,
  			    unsigned short vid)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	struct ethhdr *ethhdr;
  
  	ethhdr = eth_hdr(skb);
  
  	/* Only check for the MAC address and skip more checks here for
  	 * performance reasons - this function is on the hotpath, after all.
  	 */
  	if (!batadv_compare_eth(ethhdr->h_source,
  				bat_priv->bla.loopdetect_addr))
  		return false;
  
  	/* If the packet came too late, don't forward it on the mesh
  	 * but don't consider that as loop. It might be a coincidence.
  	 */
  	if (batadv_has_timed_out(bat_priv->bla.loopdetect_lasttime,
  				 BATADV_BLA_LOOPDETECT_TIMEOUT))
  		return true;
  
  	backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
  						 primary_if->net_dev->dev_addr,
  						 vid, true);
  	if (unlikely(!backbone_gw))
  		return true;
  
  	queue_work(batadv_event_workqueue, &backbone_gw->report_work);
  	/* backbone_gw is unreferenced in the report work function function */
  
  	return true;
  }
  
  /**
   * batadv_bla_rx - check packets coming from the mesh.
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: the frame to be checked
   * @vid: the VLAN ID of the frame
   * @is_bcast: the packet came in a broadcast packet type.
   *
   * batadv_bla_rx avoidance checks if:
   *  * we have to race for a claim
   *  * if the frame is allowed on the LAN
   *
   * in these cases, the skb is further handled by this function
   *
   * Return: true if handled, otherwise it returns false and the caller shall
   * further process the skb.
   */
  bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb,
  		   unsigned short vid, bool is_bcast)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	struct ethhdr *ethhdr;
  	struct batadv_bla_claim search_claim, *claim = NULL;
  	struct batadv_hard_iface *primary_if;
  	bool own_claim;
  	bool ret;
  
  	ethhdr = eth_hdr(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 (batadv_bla_loopdetect_check(bat_priv, skb, primary_if, vid))
  		goto handled;
  
  	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;
  
  	ether_addr_copy(search_claim.addr, ethhdr->h_source);
  	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_dbg(BATADV_DBG_BLA, bat_priv,
  			   "%s(): Unclaimed MAC %pM found. Claim it. Local: %s\n",
  			   __func__, ethhdr->h_source,
  			   batadv_is_my_client(bat_priv,
  					       ethhdr->h_source, vid) ?
  			   "yes" : "no");
  		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 ... */
  	backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
  	own_claim = batadv_compare_eth(backbone_gw->orig,
  				       primary_if->net_dev->dev_addr);
  	batadv_backbone_gw_put(backbone_gw);
  
  	if (own_claim) {
  		/* ... 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 = false;
  	goto out;
  
  handled:
  	kfree_skb(skb);
  	ret = true;
  
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  	if (claim)
  		batadv_claim_put(claim);
  	return ret;
  }
  
  /**
   * batadv_bla_tx - check packets going into the mesh
   * @bat_priv: the bat priv with all the soft interface information
   * @skb: the frame to be checked
   * @vid: the VLAN ID of the frame
   *
   * batadv_bla_tx checks if:
   *  * a claim was received which has to be processed
   *  * the frame is allowed on the mesh
   *
   * in these cases, the skb is further handled by this function.
   *
   * This call might reallocate skb data.
   *
   * Return: true if handled, otherwise it returns false and the caller shall
   * further process the skb.
   */
  bool batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb,
  		   unsigned short vid)
  {
  	struct ethhdr *ethhdr;
  	struct batadv_bla_claim search_claim, *claim = NULL;
  	struct batadv_bla_backbone_gw *backbone_gw;
  	struct batadv_hard_iface *primary_if;
  	bool client_roamed;
  	bool ret = false;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  	if (!primary_if)
  		goto out;
  
  	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
  		goto allow;
  
  	if (batadv_bla_process_claim(bat_priv, primary_if, skb))
  		goto handled;
  
  	ethhdr = eth_hdr(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;
  
  	ether_addr_copy(search_claim.addr, ethhdr->h_source);
  	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. */
  	backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
  	client_roamed = batadv_compare_eth(backbone_gw->orig,
  					   primary_if->net_dev->dev_addr);
  	batadv_backbone_gw_put(backbone_gw);
  
  	if (client_roamed) {
  		/* if yes, the client has roamed and we have
  		 * to unclaim it.
  		 */
  		if (batadv_has_timed_out(claim->lasttime, 100)) {
  			/* only unclaim if the last claim entry is
  			 * older than 100 ms to make sure we really
  			 * have a roaming client here.
  			 */
  			batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): Roaming client %pM detected. Unclaim it.\n",
  				   __func__, ethhdr->h_source);
  			batadv_handle_unclaim(bat_priv, primary_if,
  					      primary_if->net_dev->dev_addr,
  					      ethhdr->h_source, vid);
  			goto allow;
  		} else {
  			batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): Race for claim %pM detected. Drop packet.\n",
  				   __func__, ethhdr->h_source);
  			goto handled;
  		}
  	}
  
  	/* 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 = false;
  	goto out;
  handled:
  	ret = true;
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  	if (claim)
  		batadv_claim_put(claim);
  	return ret;
  }
  
  #ifdef CONFIG_BATMAN_ADV_DEBUGFS
  /**
   * batadv_bla_claim_table_seq_print_text - print the claim table in a seq file
   * @seq: seq file to print on
   * @offset: not used
   *
   * Return: always 0
   */
  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_bla_backbone_gw *backbone_gw;
  	struct batadv_bla_claim *claim;
  	struct batadv_hard_iface *primary_if;
  	struct hlist_head *head;
  	u16 backbone_crc;
  	u32 i;
  	bool is_own;
  	u8 *primary_addr;
  
  	primary_if = batadv_seq_print_text_primary_if_get(seq);
  	if (!primary_if)
  		goto out;
  
  	primary_addr = primary_if->net_dev->dev_addr;
  	seq_printf(seq,
  		   "Claims announced for the mesh %s (orig %pM, group id %#.4x)\n",
  		   net_dev->name, primary_addr,
  		   ntohs(bat_priv->bla.claim_dest.group));
  	seq_puts(seq,
  		 "   Client               VID      Originator        [o] (CRC   )\n");
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];
  
  		rcu_read_lock();
  		hlist_for_each_entry_rcu(claim, head, hash_entry) {
  			backbone_gw = batadv_bla_claim_get_backbone_gw(claim);
  
  			is_own = batadv_compare_eth(backbone_gw->orig,
  						    primary_addr);
  
  			spin_lock_bh(&backbone_gw->crc_lock);
  			backbone_crc = backbone_gw->crc;
  			spin_unlock_bh(&backbone_gw->crc_lock);
  			seq_printf(seq, " * %pM on %5d by %pM [%c] (%#.4x)\n",
  				   claim->addr, batadv_print_vid(claim->vid),
  				   backbone_gw->orig,
  				   (is_own ? 'x' : ' '),
  				   backbone_crc);
  
  			batadv_backbone_gw_put(backbone_gw);
  		}
  		rcu_read_unlock();
  	}
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  	return 0;
  }
  #endif
  
  /**
   * batadv_bla_claim_dump_entry - dump one entry of the claim table
   * to a netlink socket
   * @msg: buffer for the message
   * @portid: netlink port
   * @seq: Sequence number of netlink message
   * @primary_if: primary interface
   * @claim: entry to dump
   *
   * Return: 0 or error code.
   */
  static int
  batadv_bla_claim_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
  			    struct batadv_hard_iface *primary_if,
  			    struct batadv_bla_claim *claim)
  {
  	u8 *primary_addr = primary_if->net_dev->dev_addr;
  	u16 backbone_crc;
  	bool is_own;
  	void *hdr;
  	int ret = -EINVAL;
  
  	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
  			  NLM_F_MULTI, BATADV_CMD_GET_BLA_CLAIM);
  	if (!hdr) {
  		ret = -ENOBUFS;
  		goto out;
  	}
  
  	is_own = batadv_compare_eth(claim->backbone_gw->orig,
  				    primary_addr);
  
  	spin_lock_bh(&claim->backbone_gw->crc_lock);
  	backbone_crc = claim->backbone_gw->crc;
  	spin_unlock_bh(&claim->backbone_gw->crc_lock);
  
  	if (is_own)
  		if (nla_put_flag(msg, BATADV_ATTR_BLA_OWN)) {
  			genlmsg_cancel(msg, hdr);
  			goto out;
  		}
  
  	if (nla_put(msg, BATADV_ATTR_BLA_ADDRESS, ETH_ALEN, claim->addr) ||
  	    nla_put_u16(msg, BATADV_ATTR_BLA_VID, claim->vid) ||
  	    nla_put(msg, BATADV_ATTR_BLA_BACKBONE, ETH_ALEN,
  		    claim->backbone_gw->orig) ||
  	    nla_put_u16(msg, BATADV_ATTR_BLA_CRC,
  			backbone_crc)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	genlmsg_end(msg, hdr);
  	ret = 0;
  
  out:
  	return ret;
  }
  
  /**
   * batadv_bla_claim_dump_bucket - dump one bucket of the claim table
   * to a netlink socket
   * @msg: buffer for the message
   * @portid: netlink port
   * @seq: Sequence number of netlink message
   * @primary_if: primary interface
   * @head: bucket to dump
   * @idx_skip: How many entries to skip
   *
   * Return: always 0.
   */
  static int
  batadv_bla_claim_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
  			     struct batadv_hard_iface *primary_if,
  			     struct hlist_head *head, int *idx_skip)
  {
  	struct batadv_bla_claim *claim;
  	int idx = 0;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(claim, head, hash_entry) {
  		if (idx++ < *idx_skip)
  			continue;
  		if (batadv_bla_claim_dump_entry(msg, portid, seq,
  						primary_if, claim)) {
  			*idx_skip = idx - 1;
  			goto unlock;
  		}
  	}
  
  	*idx_skip = idx;
  unlock:
  	rcu_read_unlock();
  	return 0;
  }
  
  /**
   * batadv_bla_claim_dump - dump claim table to a netlink socket
   * @msg: buffer for the message
   * @cb: callback structure containing arguments
   *
   * Return: message length.
   */
  int batadv_bla_claim_dump(struct sk_buff *msg, struct netlink_callback *cb)
  {
  	struct batadv_hard_iface *primary_if = NULL;
  	int portid = NETLINK_CB(cb->skb).portid;
  	struct net *net = sock_net(cb->skb->sk);
  	struct net_device *soft_iface;
  	struct batadv_hashtable *hash;
  	struct batadv_priv *bat_priv;
  	int bucket = cb->args[0];
  	struct hlist_head *head;
  	int idx = cb->args[1];
  	int ifindex;
  	int ret = 0;
  
  	ifindex = batadv_netlink_get_ifindex(cb->nlh,
  					     BATADV_ATTR_MESH_IFINDEX);
  	if (!ifindex)
  		return -EINVAL;
  
  	soft_iface = dev_get_by_index(net, ifindex);
  	if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
  		ret = -ENODEV;
  		goto out;
  	}
  
  	bat_priv = netdev_priv(soft_iface);
  	hash = bat_priv->bla.claim_hash;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
  		ret = -ENOENT;
  		goto out;
  	}
  
  	while (bucket < hash->size) {
  		head = &hash->table[bucket];
  
  		if (batadv_bla_claim_dump_bucket(msg, portid,
  						 cb->nlh->nlmsg_seq,
  						 primary_if, head, &idx))
  			break;
  		bucket++;
  	}
  
  	cb->args[0] = bucket;
  	cb->args[1] = idx;
  
  	ret = msg->len;
  
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  
  	if (soft_iface)
  		dev_put(soft_iface);
  
  	return ret;
  }
  
  #ifdef CONFIG_BATMAN_ADV_DEBUGFS
  /**
   * batadv_bla_backbone_table_seq_print_text - print the backbone table in a seq
   *  file
   * @seq: seq file to print on
   * @offset: not used
   *
   * Return: always 0
   */
  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_bla_backbone_gw *backbone_gw;
  	struct batadv_hard_iface *primary_if;
  	struct hlist_head *head;
  	int secs, msecs;
  	u16 backbone_crc;
  	u32 i;
  	bool is_own;
  	u8 *primary_addr;
  
  	primary_if = batadv_seq_print_text_primary_if_get(seq);
  	if (!primary_if)
  		goto out;
  
  	primary_addr = primary_if->net_dev->dev_addr;
  	seq_printf(seq,
  		   "Backbones announced for the mesh %s (orig %pM, group id %#.4x)\n",
  		   net_dev->name, primary_addr,
  		   ntohs(bat_priv->bla.claim_dest.group));
  	seq_puts(seq, "   Originator           VID   last seen (CRC   )\n");
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];
  
  		rcu_read_lock();
  		hlist_for_each_entry_rcu(backbone_gw, 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;
  
  			spin_lock_bh(&backbone_gw->crc_lock);
  			backbone_crc = backbone_gw->crc;
  			spin_unlock_bh(&backbone_gw->crc_lock);
  
  			seq_printf(seq, " * %pM on %5d %4i.%03is (%#.4x)\n",
  				   backbone_gw->orig,
  				   batadv_print_vid(backbone_gw->vid), secs,
  				   msecs, backbone_crc);
  		}
  		rcu_read_unlock();
  	}
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  	return 0;
  }
  #endif
  
  /**
   * batadv_bla_backbone_dump_entry - dump one entry of the backbone table
   * to a netlink socket
   * @msg: buffer for the message
   * @portid: netlink port
   * @seq: Sequence number of netlink message
   * @primary_if: primary interface
   * @backbone_gw: entry to dump
   *
   * Return: 0 or error code.
   */
  static int
  batadv_bla_backbone_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
  			       struct batadv_hard_iface *primary_if,
  			       struct batadv_bla_backbone_gw *backbone_gw)
  {
  	u8 *primary_addr = primary_if->net_dev->dev_addr;
  	u16 backbone_crc;
  	bool is_own;
  	int msecs;
  	void *hdr;
  	int ret = -EINVAL;
  
  	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
  			  NLM_F_MULTI, BATADV_CMD_GET_BLA_BACKBONE);
  	if (!hdr) {
  		ret = -ENOBUFS;
  		goto out;
  	}
  
  	is_own = batadv_compare_eth(backbone_gw->orig, primary_addr);
  
  	spin_lock_bh(&backbone_gw->crc_lock);
  	backbone_crc = backbone_gw->crc;
  	spin_unlock_bh(&backbone_gw->crc_lock);
  
  	msecs = jiffies_to_msecs(jiffies - backbone_gw->lasttime);
  
  	if (is_own)
  		if (nla_put_flag(msg, BATADV_ATTR_BLA_OWN)) {
  			genlmsg_cancel(msg, hdr);
  			goto out;
  		}
  
  	if (nla_put(msg, BATADV_ATTR_BLA_BACKBONE, ETH_ALEN,
  		    backbone_gw->orig) ||
  	    nla_put_u16(msg, BATADV_ATTR_BLA_VID, backbone_gw->vid) ||
  	    nla_put_u16(msg, BATADV_ATTR_BLA_CRC,
  			backbone_crc) ||
  	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	genlmsg_end(msg, hdr);
  	ret = 0;
  
  out:
  	return ret;
  }
  
  /**
   * batadv_bla_backbone_dump_bucket - dump one bucket of the backbone table
   * to a netlink socket
   * @msg: buffer for the message
   * @portid: netlink port
   * @seq: Sequence number of netlink message
   * @primary_if: primary interface
   * @head: bucket to dump
   * @idx_skip: How many entries to skip
   *
   * Return: always 0.
   */
  static int
  batadv_bla_backbone_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
  				struct batadv_hard_iface *primary_if,
  				struct hlist_head *head, int *idx_skip)
  {
  	struct batadv_bla_backbone_gw *backbone_gw;
  	int idx = 0;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
  		if (idx++ < *idx_skip)
  			continue;
  		if (batadv_bla_backbone_dump_entry(msg, portid, seq,
  						   primary_if, backbone_gw)) {
  			*idx_skip = idx - 1;
  			goto unlock;
  		}
  	}
  
  	*idx_skip = idx;
  unlock:
  	rcu_read_unlock();
  	return 0;
  }
  
  /**
   * batadv_bla_backbone_dump - dump backbone table to a netlink socket
   * @msg: buffer for the message
   * @cb: callback structure containing arguments
   *
   * Return: message length.
   */
  int batadv_bla_backbone_dump(struct sk_buff *msg, struct netlink_callback *cb)
  {
  	struct batadv_hard_iface *primary_if = NULL;
  	int portid = NETLINK_CB(cb->skb).portid;
  	struct net *net = sock_net(cb->skb->sk);
  	struct net_device *soft_iface;
  	struct batadv_hashtable *hash;
  	struct batadv_priv *bat_priv;
  	int bucket = cb->args[0];
  	struct hlist_head *head;
  	int idx = cb->args[1];
  	int ifindex;
  	int ret = 0;
  
  	ifindex = batadv_netlink_get_ifindex(cb->nlh,
  					     BATADV_ATTR_MESH_IFINDEX);
  	if (!ifindex)
  		return -EINVAL;
  
  	soft_iface = dev_get_by_index(net, ifindex);
  	if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
  		ret = -ENODEV;
  		goto out;
  	}
  
  	bat_priv = netdev_priv(soft_iface);
  	hash = bat_priv->bla.backbone_hash;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
  		ret = -ENOENT;
  		goto out;
  	}
  
  	while (bucket < hash->size) {
  		head = &hash->table[bucket];
  
  		if (batadv_bla_backbone_dump_bucket(msg, portid,
  						    cb->nlh->nlmsg_seq,
  						    primary_if, head, &idx))
  			break;
  		bucket++;
  	}
  
  	cb->args[0] = bucket;
  	cb->args[1] = idx;
  
  	ret = msg->len;
  
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  
  	if (soft_iface)
  		dev_put(soft_iface);
  
  	return ret;
  }
  
  #ifdef CONFIG_BATMAN_ADV_DAT
  /**
   * batadv_bla_check_claim - check if address is claimed
   *
   * @bat_priv: the bat priv with all the soft interface information
   * @addr: mac address of which the claim status is checked
   * @vid: the VLAN ID
   *
   * addr is checked if this address is claimed by the local device itself.
   *
   * Return: true if bla is disabled or the mac is claimed by the device,
   * false if the device addr is already claimed by another gateway
   */
  bool batadv_bla_check_claim(struct batadv_priv *bat_priv,
  			    u8 *addr, unsigned short vid)
  {
  	struct batadv_bla_claim search_claim;
  	struct batadv_bla_claim *claim = NULL;
  	struct batadv_hard_iface *primary_if = NULL;
  	bool ret = true;
  
  	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
  		return ret;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  	if (!primary_if)
  		return ret;
  
  	/* First look if the mac address is claimed */
  	ether_addr_copy(search_claim.addr, addr);
  	search_claim.vid = vid;
  
  	claim = batadv_claim_hash_find(bat_priv, &search_claim);
  
  	/* If there is a claim and we are not owner of the claim,
  	 * return false.
  	 */
  	if (claim) {
  		if (!batadv_compare_eth(claim->backbone_gw->orig,
  					primary_if->net_dev->dev_addr))
  			ret = false;
  		batadv_claim_put(claim);
  	}
  
  	batadv_hardif_put(primary_if);
  	return ret;
  }
  #endif
  