Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2646 insertions, 0 deletions

diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
new file mode 100644
index 000000000..986f707e7
--- /dev/null
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -0,0 +1,2646 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2011-2020  B.A.T.M.A.N. contributors:
+ *
+ * Simon Wunderlich
+ */
+
+#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/gfp.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/preempt.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/batadv_packet.h>
+#include <uapi/linux/batman_adv.h>
+
+#include "hard-interface.h"
+#include "hash.h"
+#include "log.h"
+#include "netlink.h"
+#include "originator.h"
+#include "soft-interface.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_backbone_gw *gw;
+	u32 hash = 0;
+
+	gw = (struct batadv_bla_backbone_gw *)data;
+	hash = jhash(&gw->orig, sizeof(gw->orig), hash);
+	hash = jhash(&gw->vid, sizeof(gw->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)
+{
+	if (!backbone_gw)
+		return;
+
+	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)
+{
+	if (!claim)
+		return;
+
+	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);
+
+	if (in_interrupt())
+		netif_rx(skb);
+	else
+		netif_rx_ni(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;
+	struct batadv_bla_claim *claim_removed_entry;
+	struct hlist_node *claim_removed_node;
+
+	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));
+
+	claim_removed_node = batadv_hash_remove(bat_priv->bla.claim_hash,
+						batadv_compare_claim,
+						batadv_choose_claim, claim);
+	if (!claim_removed_node)
+		goto free_claim;
+
+	/* reference from the hash is gone */
+	claim_removed_entry = hlist_entry(claim_removed_node,
+					  struct batadv_bla_claim, hash_entry);
+	batadv_claim_put(claim_removed_entry);
+
+free_claim:
+	/* 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(*((__force __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 it's 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.
+		 */
+		eth_random_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);
+	if (!bat_priv->bla.claim_hash)
+		return -ENOMEM;
+
+	bat_priv->bla.backbone_hash = batadv_hash_new(32);
+	if (!bat_priv->bla.backbone_hash) {
+		batadv_hash_destroy(bat_priv->bla.claim_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_duplist() - Check if a frame is in the broadcast dup.
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: contains the multicast packet to be checked
+ * @payload_ptr: pointer to position inside the head buffer of the skb
+ *  marking the start of the data to be CRC'ed
+ * @orig: originator mac address, NULL if unknown
+ *
+ * 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.
+ */
+static bool batadv_bla_check_duplist(struct batadv_priv *bat_priv,
+				     struct sk_buff *skb, u8 *payload_ptr,
+				     const u8 *orig)
+{
+	struct batadv_bcast_duplist_entry *entry;
+	bool ret = false;
+	int i, curr;
+	__be32 crc;
+
+	/* calculate the crc ... */
+	crc = batadv_skb_crc32(skb, payload_ptr);
+
+	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;
+
+		/* are the originators both known and not anonymous? */
+		if (orig && !is_zero_ether_addr(orig) &&
+		    !is_zero_ether_addr(entry->orig)) {
+			/* If known, check if the new frame came from
+			 * the same originator:
+			 * We are safe to take identical frames from the
+			 * same orig, if known, as multiplications in
+			 * the mesh are detected via the (orig, seqno) pair.
+			 * So we can be a bit more liberal here and allow
+			 * identical frames from the same orig which the source
+			 * host might have sent multiple times on purpose.
+			 */
+			if (batadv_compare_eth(entry->orig, 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;
+
+	/* known originator */
+	if (orig)
+		ether_addr_copy(entry->orig, orig);
+	/* anonymous originator */
+	else
+		eth_zero_addr(entry->orig);
+
+	bat_priv->bla.bcast_duplist_curr = curr;
+
+out:
+	spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);
+
+	return ret;
+}
+
+/**
+ * batadv_bla_check_ucast_duplist() - Check if a frame is in the broadcast dup.
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: contains the multicast packet to be checked, decapsulated from a
+ *  unicast_packet
+ *
+ * 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.
+ *
+ * Return: true if a packet is in the duplicate list, false otherwise.
+ */
+static bool batadv_bla_check_ucast_duplist(struct batadv_priv *bat_priv,
+					   struct sk_buff *skb)
+{
+	return batadv_bla_check_duplist(bat_priv, skb, (u8 *)skb->data, NULL);
+}
+
+/**
+ * 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.
+ *
+ * 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)
+{
+	struct batadv_bcast_packet *bcast_packet;
+	u8 *payload_ptr;
+
+	bcast_packet = (struct batadv_bcast_packet *)skb->data;
+	payload_ptr = (u8 *)(bcast_packet + 1);
+
+	return batadv_bla_check_duplist(bat_priv, skb, payload_ptr,
+					bcast_packet->orig);
+}
+
+/**
+ * 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,
+ * throws an uevent and logs 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;
+	bool ret;
+
+	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;
+
+	ret = queue_work(batadv_event_workqueue, &backbone_gw->report_work);
+
+	/* backbone_gw is unreferenced in the report work function
+	 * if queue_work() call was successful
+	 */
+	if (!ret)
+		batadv_backbone_gw_put(backbone_gw);
+
+	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
+ * @packet_type: the batman packet type this frame came in
+ *
+ * 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, int packet_type)
+{
+	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 multicast packets while requests are in flight */
+		if (is_multicast_ether_addr(ethhdr->h_dest))
+			/* Both broadcast flooding or multicast-via-unicasts
+			 * delivery might send to multiple backbone gateways
+			 * sharing the same LAN and therefore need to coordinate
+			 * which backbone gateway forwards into the LAN,
+			 * by claiming the payload source address.
+			 *
+			 * Broadcast flooding and multicast-via-unicasts
+			 * delivery use the following two batman packet types.
+			 * Note: explicitly exclude BATADV_UNICAST_4ADDR,
+			 * as the DHCP gateway feature will send explicitly
+			 * to only one BLA gateway, so the claiming process
+			 * should be avoided there.
+			 */
+			if (packet_type == BATADV_BCAST ||
+			    packet_type == BATADV_UNICAST)
+				goto handled;
+
+	/* potential duplicates from foreign BLA backbone gateways via
+	 * multicast-in-unicast packets
+	 */
+	if (is_multicast_ether_addr(ethhdr->h_dest) &&
+	    packet_type == BATADV_UNICAST &&
+	    batadv_bla_check_ucast_duplist(bat_priv, skb))
+		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 multicast ... */
+	if (is_multicast_ether_addr(ethhdr->h_dest) &&
+	    (packet_type == BATADV_BCAST || packet_type == BATADV_UNICAST)) {
+		/* ... drop it. the responsible gateway is in charge.
+		 *
+		 * We need to check packet type because with the gateway
+		 * feature, broadcasts (like DHCP requests) may be sent
+		 * using a unicast 4 address packet type. See comment above.
+		 */
+		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
+ * @cb: Control block containing additional options
+ * @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,
+			    struct netlink_callback *cb,
+			    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, cb->nlh->nlmsg_seq,
+			  &batadv_netlink_family, NLM_F_MULTI,
+			  BATADV_CMD_GET_BLA_CLAIM);
+	if (!hdr) {
+		ret = -ENOBUFS;
+		goto out;
+	}
+
+	genl_dump_check_consistent(cb, hdr);
+
+	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
+ * @cb: Control block containing additional options
+ * @primary_if: primary interface
+ * @hash: hash to dump
+ * @bucket: bucket index 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,
+			     struct netlink_callback *cb,
+			     struct batadv_hard_iface *primary_if,
+			     struct batadv_hashtable *hash, unsigned int bucket,
+			     int *idx_skip)
+{
+	struct batadv_bla_claim *claim;
+	int idx = 0;
+	int ret = 0;
+
+	spin_lock_bh(&hash->list_locks[bucket]);
+	cb->seq = atomic_read(&hash->generation) << 1 | 1;
+
+	hlist_for_each_entry(claim, &hash->table[bucket], hash_entry) {
+		if (idx++ < *idx_skip)
+			continue;
+
+		ret = batadv_bla_claim_dump_entry(msg, portid, cb,
+						  primary_if, claim);
+		if (ret) {
+			*idx_skip = idx - 1;
+			goto unlock;
+		}
+	}
+
+	*idx_skip = 0;
+unlock:
+	spin_unlock_bh(&hash->list_locks[bucket]);
+	return ret;
+}
+
+/**
+ * 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];
+	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) {
+		if (batadv_bla_claim_dump_bucket(msg, portid, cb, primary_if,
+						 hash, bucket, &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
+ * @cb: Control block containing additional options
+ * @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,
+			       struct netlink_callback *cb,
+			       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, cb->nlh->nlmsg_seq,
+			  &batadv_netlink_family, NLM_F_MULTI,
+			  BATADV_CMD_GET_BLA_BACKBONE);
+	if (!hdr) {
+		ret = -ENOBUFS;
+		goto out;
+	}
+
+	genl_dump_check_consistent(cb, hdr);
+
+	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
+ * @cb: Control block containing additional options
+ * @primary_if: primary interface
+ * @hash: hash to dump
+ * @bucket: bucket index 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,
+				struct netlink_callback *cb,
+				struct batadv_hard_iface *primary_if,
+				struct batadv_hashtable *hash,
+				unsigned int bucket, int *idx_skip)
+{
+	struct batadv_bla_backbone_gw *backbone_gw;
+	int idx = 0;
+	int ret = 0;
+
+	spin_lock_bh(&hash->list_locks[bucket]);
+	cb->seq = atomic_read(&hash->generation) << 1 | 1;
+
+	hlist_for_each_entry(backbone_gw, &hash->table[bucket], hash_entry) {
+		if (idx++ < *idx_skip)
+			continue;
+
+		ret = batadv_bla_backbone_dump_entry(msg, portid, cb,
+						     primary_if, backbone_gw);
+		if (ret) {
+			*idx_skip = idx - 1;
+			goto unlock;
+		}
+	}
+
+	*idx_skip = 0;
+unlock:
+	spin_unlock_bh(&hash->list_locks[bucket]);
+	return ret;
+}
+
+/**
+ * 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];
+	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) {
+		if (batadv_bla_backbone_dump_bucket(msg, portid, cb, primary_if,
+						    hash, bucket, &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