/* Copyright (C) 2011-2014 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 "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_bla_backbone_gw *backbone_gw);

  
  /* return the index of the claim */

  static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)

  {

  	struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;

  	uint32_t hash = 0;

  	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
  	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));

  
  	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 struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;

  	uint32_t hash = 0;

  	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
  	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));

  
  	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_bla_backbone_gw,

  					 hash_entry);

  	const struct batadv_bla_backbone_gw *gw1 = data1, *gw2 = data2;

  	if (!batadv_compare_eth(gw1->orig, gw2->orig))
  		return 0;
  
  	if (gw1->vid != gw2->vid)
  		return 0;
  
  	return 1;

  }
  
  /* 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_bla_claim,

  					 hash_entry);

  	const struct batadv_bla_claim *cl1 = data1, *cl2 = data2;

  
  	if (!batadv_compare_eth(cl1->addr, cl2->addr))
  		return 0;
  
  	if (cl1->vid != cl2->vid)
  		return 0;

  	return 1;

  }
  
  /* free a backbone gw */

  static void
  batadv_backbone_gw_free_ref(struct batadv_bla_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_bla_claim *claim;

  	claim = container_of(rcu, struct batadv_bla_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_bla_claim *claim)

  {
  	if (atomic_dec_and_test(&claim->refcount))

  		call_rcu(&claim->rcu, batadv_claim_free_rcu);

  }

  /**
   * batadv_claim_hash_find
   * @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_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 (!atomic_inc_not_zero(&claim->refcount))
  			continue;
  
  		claim_tmp = claim;
  		break;
  	}
  	rcu_read_unlock();
  
  	return claim_tmp;
  }

  /**
   * batadv_backbone_hash_find - looks for a claim in the hash
   * @bat_priv: the bat priv with all the soft interface information

   * @addr: the address of the originator
   * @vid: the VLAN ID
   *

   * Returns claim if found or NULL otherwise.

   */

  static struct batadv_bla_backbone_gw *

  batadv_backbone_hash_find(struct batadv_priv *bat_priv,

  			  uint8_t *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 (!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_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_free_ref(claim);

  			hlist_del_rcu(&claim->hash_entry);

  		}
  		spin_unlock_bh(list_lock);
  	}
  
  	/* all claims gone, intialize CRC */

  	backbone_gw->crc = BATADV_BLA_CRC_INIT;

  }

  /**
   * batadv_bla_send_claim - sends a claim frame according to the provided info
   * @bat_priv: the bat priv with all the soft interface information

   * @orig: 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, uint8_t *mac,

  				  unsigned 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
  		 */

  		ether_addr_copy(ethhdr->h_source, mac);

  		batadv_dbg(BATADV_DBG_BLA, bat_priv,

  			   "bla_send_claim(): CLAIM %pM on vid %d
  ", 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,

  			   "bla_send_claim(): UNCLAIM %pM on vid %d
  ", 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,

  			   "bla_send_claim(): ANNOUNCE of %pM on vid %d
  ",

  			   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,

  			   "bla_send_claim(): REQUEST of %pM to %pM on vid %d
  ",

  			   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);

  
  	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);

  }

  /**
   * batadv_bla_get_backbone_gw
   * @bat_priv: the bat priv with all the soft interface information

   * @orig: the mac address of the originator
   * @vid: the VLAN ID
   *
   * searches for the backbone gw or creates a new one if it could not
   * be found.
   */

  static struct batadv_bla_backbone_gw *

  batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *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,

  		   "bla_get_backbone_gw(): not found (%pM, %d), creating new entry
  ",

  		   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;
  	atomic_set(&entry->request_sent, 0);

  	atomic_set(&entry->wait_periods, 0);

  	ether_addr_copy(entry->orig, orig);

  
  	/* 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 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_free_ref(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;
  }
  
  /* 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_free_ref(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

   * @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,

  		   "bla_answer_request(): received a claim request, send all of our own claims again
  ");

  	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_free_ref(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
  ", 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
   * @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_bla_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);

  }

  /**
   * 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 uint8_t *mac, const unsigned short vid,

  				 struct batadv_bla_backbone_gw *backbone_gw)

  {

  	struct batadv_bla_claim *claim;
  	struct batadv_bla_claim search_claim;

  	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);

  		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 ...
  ",

  			   mac, BATADV_PRINT_VID(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
  ",

  			   mac, BATADV_PRINT_VID(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 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, "bla_del_claim(): %pM, vid %d
  ",

  		   mac, BATADV_PRINT_VID(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,

  				  unsigned short vid)

  {

  	struct batadv_bla_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,
  						 false);

  
  	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 = %#.4x
  ",

  		   BATADV_PRINT_VID(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 = %#.4x, sent = %#.4x)
  ",

  			   backbone_gw->orig,
  			   BATADV_PRINT_VID(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, unsigned 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)...
  ",

  		   BATADV_PRINT_VID(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, 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 1;
  
  	/* this must be an UNCLAIM frame */

  	batadv_dbg(BATADV_DBG_BLA, bat_priv,

  		   "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...
  ",

  		   claim_addr, BATADV_PRINT_VID(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,

  			       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 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;
  }

  /**
   * batadv_check_claim_group
   * @bat_priv: the bat priv with all the soft interface information

   * @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.
   *
   * returns:
   *	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,

  				    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: %#.4x
  ",

  			   ntohs(bla_dst->group));

  		bla_dst_own->group = bla_dst->group;
  	}

  	batadv_orig_node_free_ref(orig_node);

  
  	return 2;
  }

  /**
   * batadv_bla_process_claim
   * @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 batadv_bla_claim_dst *bla_dst;
  	uint8_t *hw_src, *hw_dst;

  	struct vlan_ethhdr *vhdr;

  	struct ethhdr *ethhdr;

  	struct arphdr *arphdr;

  	unsigned short vid;

  	__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) {

  		vhdr = vlan_eth_hdr(skb);

  		proto = vhdr->h_vlan_encapsulated_proto;

  		headlen += VLAN_HLEN;

  	}

  	if (proto != htons(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 = eth_hdr(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)
  ",

  			   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 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)
  ",

  		   ethhdr->h_source, BATADV_PRINT_VID(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_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,

  				   "bla_purge_backbone_gw(): backbone gw %pM timed out
  ",
  				   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_free_ref(backbone_gw);

  		}
  		spin_unlock_bh(list_lock);
  	}
  }

  /**
   * batadv_bla_purge_claims
   * @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_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) {

  			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
  ",
  				   claim->addr, claim->vid);

  
  purge_now:

  			batadv_handle_unclaim(bat_priv, primary_if,
  					      claim->backbone_gw->orig,
  					      claim->addr, claim->vid);

  		}
  		rcu_read_unlock();
  	}
  }

  /**
   * batadv_bla_update_orig_address
   * @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
   *
   * Update the backbone gateways when the own orig address changes.

   */

  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();
  	}
  }

  /* 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;

  	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, 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);

  
  			/* 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_free_ref(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;

  /* 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
  ");

  	/* 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
  ");

  	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
   * @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.

   */

  int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,

  				   struct sk_buff *skb)

  {

  	int i, curr, ret = 0;
  	__be32 crc;
  	struct batadv_bcast_packet *bcast_packet;

  	struct batadv_bcast_duplist_entry *entry;

  	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 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;

  	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
   * @bat_priv: the bat priv with all the soft interface information

   * @orig: originator mac address

   * @vid: VLAN identifier

   *

   * Check if the originator is a gateway for the VLAN identified by vid.

   *

   * Returns true if orig is a backbone for this vid, false otherwise.

   */

  bool batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *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))