OSCL-LXR linux-6.0.1/​net/​batman-adv/​bridge_loop_avoidance.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (C) 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/container_of.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/rculist.h>
 #include <linux/rcupdate.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)
 {
     const struct batadv_bla_claim *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 = 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, const 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, const 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 containing the crc
          */
         ether_addr_copy(hw_src, mac);
         batadv_dbg(BATADV_DBG_BLA, bat_priv,
                "%s(): ANNOUNCE of %pM on vid %d\n", __func__,
                ethhdr->h_source, batadv_print_vid(vid));
         break;
     case BATADV_CLAIM_TYPE_REQUEST:
         /* request frame
          * set HW SRC and header destination to the receiving backbone
          * gws mac
          */
         ether_addr_copy(hw_src, mac);
         ether_addr_copy(ethhdr->h_dest, mac);
         batadv_dbg(BATADV_DBG_BLA, bat_priv,
                "%s(): REQUEST of %pM to %pM on vid %d\n", __func__,
                ethhdr->h_source, ethhdr->h_dest,
                batadv_print_vid(vid));
         break;
     case BATADV_CLAIM_TYPE_LOOPDETECT:
         ether_addr_copy(ethhdr->h_source, mac);
         batadv_dbg(BATADV_DBG_BLA, bat_priv,
                "%s(): LOOPDETECT of %pM to %pM on vid %d\n",
                __func__, ethhdr->h_source, ethhdr->h_dest,
                batadv_print_vid(vid));
 
         break;
     }
 
     if (vid & BATADV_VLAN_HAS_TAG) {
         skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
                       vid & VLAN_VID_MASK);
         if (!skb)
             goto out;
     }
 
     skb_reset_mac_header(skb);
     skb->protocol = eth_type_trans(skb, soft_iface);
     batadv_inc_counter(bat_priv, BATADV_CNT_RX);
     batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
                skb->len + ETH_HLEN);
 
     netif_rx(skb);
 out:
     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, const 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,
                   const u8 *backbone_addr, const 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,
                 const u8 *backbone_addr, const 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);
 
     /* don't 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:
     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;
     }
     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:
     batadv_hardif_put(primary_if);
     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:
     batadv_hardif_put(primary_if);
     batadv_claim_put(claim);
     return ret;
 }
 
 /**
  * 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)
 {
     const 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:
     batadv_hardif_put(primary_if);
 
     dev_put(soft_iface);
 
     return ret;
 }
 
 /**
  * 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)
 {
     const 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:
     batadv_hardif_put(primary_if);
 
     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

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