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	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-only
 /*
  * Copyright (c) 2008, 2009 open80211s Ltd.
  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
  */
 
 #include <linux/etherdevice.h>
 #include <linux/list.h>
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <net/mac80211.h>
 #include "wme.h"
 #include "ieee80211_i.h"
 #include "mesh.h"
 
 static void mesh_path_free_rcu(struct mesh_table *tbl, struct mesh_path *mpath);
 
 static u32 mesh_table_hash(const void *addr, u32 len, u32 seed)
 {
     /* Use last four bytes of hw addr as hash index */
     return jhash_1word(__get_unaligned_cpu32((u8 *)addr + 2), seed);
 }
 
 static const struct rhashtable_params mesh_rht_params = {
     .nelem_hint = 2,
     .automatic_shrinking = true,
     .key_len = ETH_ALEN,
     .key_offset = offsetof(struct mesh_path, dst),
     .head_offset = offsetof(struct mesh_path, rhash),
     .hashfn = mesh_table_hash,
 };
 
 static inline bool mpath_expired(struct mesh_path *mpath)
 {
     return (mpath->flags & MESH_PATH_ACTIVE) &&
            time_after(jiffies, mpath->exp_time) &&
            !(mpath->flags & MESH_PATH_FIXED);
 }
 
 static void mesh_path_rht_free(void *ptr, void *tblptr)
 {
     struct mesh_path *mpath = ptr;
     struct mesh_table *tbl = tblptr;
 
     mesh_path_free_rcu(tbl, mpath);
 }
 
 static void mesh_table_init(struct mesh_table *tbl)
 {
     INIT_HLIST_HEAD(&tbl->known_gates);
     INIT_HLIST_HEAD(&tbl->walk_head);
     atomic_set(&tbl->entries,  0);
     spin_lock_init(&tbl->gates_lock);
     spin_lock_init(&tbl->walk_lock);
 
     /* rhashtable_init() may fail only in case of wrong
      * mesh_rht_params
      */
     WARN_ON(rhashtable_init(&tbl->rhead, &mesh_rht_params));
 }
 
 static void mesh_table_free(struct mesh_table *tbl)
 {
     rhashtable_free_and_destroy(&tbl->rhead,
                     mesh_path_rht_free, tbl);
 }
 
 /**
  * mesh_path_assign_nexthop - update mesh path next hop
  *
  * @mpath: mesh path to update
  * @sta: next hop to assign
  *
  * Locking: mpath->state_lock must be held when calling this function
  */
 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta)
 {
     struct sk_buff *skb;
     struct ieee80211_hdr *hdr;
     unsigned long flags;
 
     rcu_assign_pointer(mpath->next_hop, sta);
 
     spin_lock_irqsave(&mpath->frame_queue.lock, flags);
     skb_queue_walk(&mpath->frame_queue, skb) {
         hdr = (struct ieee80211_hdr *) skb->data;
         memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
         memcpy(hdr->addr2, mpath->sdata->vif.addr, ETH_ALEN);
         ieee80211_mps_set_frame_flags(sta->sdata, sta, hdr);
     }
 
     spin_unlock_irqrestore(&mpath->frame_queue.lock, flags);
 }
 
 static void prepare_for_gate(struct sk_buff *skb, char *dst_addr,
                  struct mesh_path *gate_mpath)
 {
     struct ieee80211_hdr *hdr;
     struct ieee80211s_hdr *mshdr;
     int mesh_hdrlen, hdrlen;
     char *next_hop;
 
     hdr = (struct ieee80211_hdr *) skb->data;
     hdrlen = ieee80211_hdrlen(hdr->frame_control);
     mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
 
     if (!(mshdr->flags & MESH_FLAGS_AE)) {
         /* size of the fixed part of the mesh header */
         mesh_hdrlen = 6;
 
         /* make room for the two extended addresses */
         skb_push(skb, 2 * ETH_ALEN);
         memmove(skb->data, hdr, hdrlen + mesh_hdrlen);
 
         hdr = (struct ieee80211_hdr *) skb->data;
 
         /* we preserve the previous mesh header and only add
          * the new addresses */
         mshdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
         mshdr->flags = MESH_FLAGS_AE_A5_A6;
         memcpy(mshdr->eaddr1, hdr->addr3, ETH_ALEN);
         memcpy(mshdr->eaddr2, hdr->addr4, ETH_ALEN);
     }
 
     /* update next hop */
     hdr = (struct ieee80211_hdr *) skb->data;
     rcu_read_lock();
     next_hop = rcu_dereference(gate_mpath->next_hop)->sta.addr;
     memcpy(hdr->addr1, next_hop, ETH_ALEN);
     rcu_read_unlock();
     memcpy(hdr->addr2, gate_mpath->sdata->vif.addr, ETH_ALEN);
     memcpy(hdr->addr3, dst_addr, ETH_ALEN);
 }
 
 /**
  * mesh_path_move_to_queue - Move or copy frames from one mpath queue to another
  *
  * This function is used to transfer or copy frames from an unresolved mpath to
  * a gate mpath.  The function also adds the Address Extension field and
  * updates the next hop.
  *
  * If a frame already has an Address Extension field, only the next hop and
  * destination addresses are updated.
  *
  * The gate mpath must be an active mpath with a valid mpath->next_hop.
  *
  * @gate_mpath: An active mpath the frames will be sent to (i.e. the gate)
  * @from_mpath: The failed mpath
  * @copy: When true, copy all the frames to the new mpath queue.  When false,
  * move them.
  */
 static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
                     struct mesh_path *from_mpath,
                     bool copy)
 {
     struct sk_buff *skb, *fskb, *tmp;
     struct sk_buff_head failq;
     unsigned long flags;
 
     if (WARN_ON(gate_mpath == from_mpath))
         return;
     if (WARN_ON(!gate_mpath->next_hop))
         return;
 
     __skb_queue_head_init(&failq);
 
     spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
     skb_queue_splice_init(&from_mpath->frame_queue, &failq);
     spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 
     skb_queue_walk_safe(&failq, fskb, tmp) {
         if (skb_queue_len(&gate_mpath->frame_queue) >=
                   MESH_FRAME_QUEUE_LEN) {
             mpath_dbg(gate_mpath->sdata, "mpath queue full!\n");
             break;
         }
 
         skb = skb_copy(fskb, GFP_ATOMIC);
         if (WARN_ON(!skb))
             break;
 
         prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
         skb_queue_tail(&gate_mpath->frame_queue, skb);
 
         if (copy)
             continue;
 
         __skb_unlink(fskb, &failq);
         kfree_skb(fskb);
     }
 
     mpath_dbg(gate_mpath->sdata, "Mpath queue for gate %pM has %d frames\n",
           gate_mpath->dst, skb_queue_len(&gate_mpath->frame_queue));
 
     if (!copy)
         return;
 
     spin_lock_irqsave(&from_mpath->frame_queue.lock, flags);
     skb_queue_splice(&failq, &from_mpath->frame_queue);
     spin_unlock_irqrestore(&from_mpath->frame_queue.lock, flags);
 }
 
 
 static struct mesh_path *mpath_lookup(struct mesh_table *tbl, const u8 *dst,
                       struct ieee80211_sub_if_data *sdata)
 {
     struct mesh_path *mpath;
 
     mpath = rhashtable_lookup(&tbl->rhead, dst, mesh_rht_params);
 
     if (mpath && mpath_expired(mpath)) {
         spin_lock_bh(&mpath->state_lock);
         mpath->flags &= ~MESH_PATH_ACTIVE;
         spin_unlock_bh(&mpath->state_lock);
     }
     return mpath;
 }
 
 /**
  * mesh_path_lookup - look up a path in the mesh path table
  * @sdata: local subif
  * @dst: hardware address (ETH_ALEN length) of destination
  *
  * Returns: pointer to the mesh path structure, or NULL if not found
  *
  * Locking: must be called within a read rcu section.
  */
 struct mesh_path *
 mesh_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 {
     return mpath_lookup(&sdata->u.mesh.mesh_paths, dst, sdata);
 }
 
 struct mesh_path *
 mpp_path_lookup(struct ieee80211_sub_if_data *sdata, const u8 *dst)
 {
     return mpath_lookup(&sdata->u.mesh.mpp_paths, dst, sdata);
 }
 
 static struct mesh_path *
 __mesh_path_lookup_by_idx(struct mesh_table *tbl, int idx)
 {
     int i = 0;
     struct mesh_path *mpath;
 
     hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
         if (i++ == idx)
             break;
     }
 
     if (!mpath)
         return NULL;
 
     if (mpath_expired(mpath)) {
         spin_lock_bh(&mpath->state_lock);
         mpath->flags &= ~MESH_PATH_ACTIVE;
         spin_unlock_bh(&mpath->state_lock);
     }
     return mpath;
 }
 
 /**
  * mesh_path_lookup_by_idx - look up a path in the mesh path table by its index
  * @idx: index
  * @sdata: local subif, or NULL for all entries
  *
  * Returns: pointer to the mesh path structure, or NULL if not found.
  *
  * Locking: must be called within a read rcu section.
  */
 struct mesh_path *
 mesh_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 {
     return __mesh_path_lookup_by_idx(&sdata->u.mesh.mesh_paths, idx);
 }
 
 /**
  * mpp_path_lookup_by_idx - look up a path in the proxy path table by its index
  * @idx: index
  * @sdata: local subif, or NULL for all entries
  *
  * Returns: pointer to the proxy path structure, or NULL if not found.
  *
  * Locking: must be called within a read rcu section.
  */
 struct mesh_path *
 mpp_path_lookup_by_idx(struct ieee80211_sub_if_data *sdata, int idx)
 {
     return __mesh_path_lookup_by_idx(&sdata->u.mesh.mpp_paths, idx);
 }
 
 /**
  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
  * @mpath: gate path to add to table
  */
 int mesh_path_add_gate(struct mesh_path *mpath)
 {
     struct mesh_table *tbl;
     int err;
 
     rcu_read_lock();
     tbl = &mpath->sdata->u.mesh.mesh_paths;
 
     spin_lock_bh(&mpath->state_lock);
     if (mpath->is_gate) {
         err = -EEXIST;
         spin_unlock_bh(&mpath->state_lock);
         goto err_rcu;
     }
     mpath->is_gate = true;
     mpath->sdata->u.mesh.num_gates++;
 
     spin_lock(&tbl->gates_lock);
     hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
     spin_unlock(&tbl->gates_lock);
 
     spin_unlock_bh(&mpath->state_lock);
 
     mpath_dbg(mpath->sdata,
           "Mesh path: Recorded new gate: %pM. %d known gates\n",
           mpath->dst, mpath->sdata->u.mesh.num_gates);
     err = 0;
 err_rcu:
     rcu_read_unlock();
     return err;
 }
 
 /**
  * mesh_gate_del - remove a mesh gate from the list of known gates
  * @tbl: table which holds our list of known gates
  * @mpath: gate mpath
  */
 static void mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 {
     lockdep_assert_held(&mpath->state_lock);
     if (!mpath->is_gate)
         return;
 
     mpath->is_gate = false;
     spin_lock_bh(&tbl->gates_lock);
     hlist_del_rcu(&mpath->gate_list);
     mpath->sdata->u.mesh.num_gates--;
     spin_unlock_bh(&tbl->gates_lock);
 
     mpath_dbg(mpath->sdata,
           "Mesh path: Deleted gate: %pM. %d known gates\n",
           mpath->dst, mpath->sdata->u.mesh.num_gates);
 }
 
 /**
  * mesh_gate_num - number of gates known to this interface
  * @sdata: subif data
  */
 int mesh_gate_num(struct ieee80211_sub_if_data *sdata)
 {
     return sdata->u.mesh.num_gates;
 }
 
 static
 struct mesh_path *mesh_path_new(struct ieee80211_sub_if_data *sdata,
                 const u8 *dst, gfp_t gfp_flags)
 {
     struct mesh_path *new_mpath;
 
     new_mpath = kzalloc(sizeof(struct mesh_path), gfp_flags);
     if (!new_mpath)
         return NULL;
 
     memcpy(new_mpath->dst, dst, ETH_ALEN);
     eth_broadcast_addr(new_mpath->rann_snd_addr);
     new_mpath->is_root = false;
     new_mpath->sdata = sdata;
     new_mpath->flags = 0;
     skb_queue_head_init(&new_mpath->frame_queue);
     new_mpath->exp_time = jiffies;
     spin_lock_init(&new_mpath->state_lock);
     timer_setup(&new_mpath->timer, mesh_path_timer, 0);
 
     return new_mpath;
 }
 
 /**
  * mesh_path_add - allocate and add a new path to the mesh path table
  * @dst: destination address of the path (ETH_ALEN length)
  * @sdata: local subif
  *
  * Returns: 0 on success
  *
  * State: the initial state of the new path is set to 0
  */
 struct mesh_path *mesh_path_add(struct ieee80211_sub_if_data *sdata,
                 const u8 *dst)
 {
     struct mesh_table *tbl;
     struct mesh_path *mpath, *new_mpath;
 
     if (ether_addr_equal(dst, sdata->vif.addr))
         /* never add ourselves as neighbours */
         return ERR_PTR(-ENOTSUPP);
 
     if (is_multicast_ether_addr(dst))
         return ERR_PTR(-ENOTSUPP);
 
     if (atomic_add_unless(&sdata->u.mesh.mpaths, 1, MESH_MAX_MPATHS) == 0)
         return ERR_PTR(-ENOSPC);
 
     new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
     if (!new_mpath)
         return ERR_PTR(-ENOMEM);
 
     tbl = &sdata->u.mesh.mesh_paths;
     spin_lock_bh(&tbl->walk_lock);
     mpath = rhashtable_lookup_get_insert_fast(&tbl->rhead,
                           &new_mpath->rhash,
                           mesh_rht_params);
     if (!mpath)
         hlist_add_head(&new_mpath->walk_list, &tbl->walk_head);
     spin_unlock_bh(&tbl->walk_lock);
 
     if (mpath) {
         kfree(new_mpath);
 
         if (IS_ERR(mpath))
             return mpath;
 
         new_mpath = mpath;
     }
 
     sdata->u.mesh.mesh_paths_generation++;
     return new_mpath;
 }
 
 int mpp_path_add(struct ieee80211_sub_if_data *sdata,
          const u8 *dst, const u8 *mpp)
 {
     struct mesh_table *tbl;
     struct mesh_path *new_mpath;
     int ret;
 
     if (ether_addr_equal(dst, sdata->vif.addr))
         /* never add ourselves as neighbours */
         return -ENOTSUPP;
 
     if (is_multicast_ether_addr(dst))
         return -ENOTSUPP;
 
     new_mpath = mesh_path_new(sdata, dst, GFP_ATOMIC);
 
     if (!new_mpath)
         return -ENOMEM;
 
     memcpy(new_mpath->mpp, mpp, ETH_ALEN);
     tbl = &sdata->u.mesh.mpp_paths;
 
     spin_lock_bh(&tbl->walk_lock);
     ret = rhashtable_lookup_insert_fast(&tbl->rhead,
                         &new_mpath->rhash,
                         mesh_rht_params);
     if (!ret)
         hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
     spin_unlock_bh(&tbl->walk_lock);
 
     if (ret)
         kfree(new_mpath);
 
     sdata->u.mesh.mpp_paths_generation++;
     return ret;
 }
 
 
 /**
  * mesh_plink_broken - deactivates paths and sends perr when a link breaks
  *
  * @sta: broken peer link
  *
  * This function must be called from the rate control algorithm if enough
  * delivery errors suggest that a peer link is no longer usable.
  */
 void mesh_plink_broken(struct sta_info *sta)
 {
     struct ieee80211_sub_if_data *sdata = sta->sdata;
     struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
     static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
     struct mesh_path *mpath;
 
     rcu_read_lock();
     hlist_for_each_entry_rcu(mpath, &tbl->walk_head, walk_list) {
         if (rcu_access_pointer(mpath->next_hop) == sta &&
             mpath->flags & MESH_PATH_ACTIVE &&
             !(mpath->flags & MESH_PATH_FIXED)) {
             spin_lock_bh(&mpath->state_lock);
             mpath->flags &= ~MESH_PATH_ACTIVE;
             ++mpath->sn;
             spin_unlock_bh(&mpath->state_lock);
             mesh_path_error_tx(sdata,
                 sdata->u.mesh.mshcfg.element_ttl,
                 mpath->dst, mpath->sn,
                 WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
         }
     }
     rcu_read_unlock();
 }
 
 static void mesh_path_free_rcu(struct mesh_table *tbl,
                    struct mesh_path *mpath)
 {
     struct ieee80211_sub_if_data *sdata = mpath->sdata;
 
     spin_lock_bh(&mpath->state_lock);
     mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
     mesh_gate_del(tbl, mpath);
     spin_unlock_bh(&mpath->state_lock);
     del_timer_sync(&mpath->timer);
     atomic_dec(&sdata->u.mesh.mpaths);
     atomic_dec(&tbl->entries);
     mesh_path_flush_pending(mpath);
     kfree_rcu(mpath, rcu);
 }
 
 static void __mesh_path_del(struct mesh_table *tbl, struct mesh_path *mpath)
 {
     hlist_del_rcu(&mpath->walk_list);
     rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, mesh_rht_params);
     mesh_path_free_rcu(tbl, mpath);
 }
 
 /**
  * mesh_path_flush_by_nexthop - Deletes mesh paths if their next hop matches
  *
  * @sta: mesh peer to match
  *
  * RCU notes: this function is called when a mesh plink transitions from
  * PLINK_ESTAB to any other state, since PLINK_ESTAB state is the only one that
  * allows path creation. This will happen before the sta can be freed (because
  * sta_info_destroy() calls this) so any reader in a rcu read block will be
  * protected against the plink disappearing.
  */
 void mesh_path_flush_by_nexthop(struct sta_info *sta)
 {
     struct ieee80211_sub_if_data *sdata = sta->sdata;
     struct mesh_table *tbl = &sdata->u.mesh.mesh_paths;
     struct mesh_path *mpath;
     struct hlist_node *n;
 
     spin_lock_bh(&tbl->walk_lock);
     hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
         if (rcu_access_pointer(mpath->next_hop) == sta)
             __mesh_path_del(tbl, mpath);
     }
     spin_unlock_bh(&tbl->walk_lock);
 }
 
 static void mpp_flush_by_proxy(struct ieee80211_sub_if_data *sdata,
                    const u8 *proxy)
 {
     struct mesh_table *tbl = &sdata->u.mesh.mpp_paths;
     struct mesh_path *mpath;
     struct hlist_node *n;
 
     spin_lock_bh(&tbl->walk_lock);
     hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
         if (ether_addr_equal(mpath->mpp, proxy))
             __mesh_path_del(tbl, mpath);
     }
     spin_unlock_bh(&tbl->walk_lock);
 }
 
 static void table_flush_by_iface(struct mesh_table *tbl)
 {
     struct mesh_path *mpath;
     struct hlist_node *n;
 
     spin_lock_bh(&tbl->walk_lock);
     hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
         __mesh_path_del(tbl, mpath);
     }
     spin_unlock_bh(&tbl->walk_lock);
 }
 
 /**
  * mesh_path_flush_by_iface - Deletes all mesh paths associated with a given iface
  *
  * This function deletes both mesh paths as well as mesh portal paths.
  *
  * @sdata: interface data to match
  *
  */
 void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
 {
     table_flush_by_iface(&sdata->u.mesh.mesh_paths);
     table_flush_by_iface(&sdata->u.mesh.mpp_paths);
 }
 
 /**
  * table_path_del - delete a path from the mesh or mpp table
  *
  * @tbl: mesh or mpp path table
  * @sdata: local subif
  * @addr: dst address (ETH_ALEN length)
  *
  * Returns: 0 if successful
  */
 static int table_path_del(struct mesh_table *tbl,
               struct ieee80211_sub_if_data *sdata,
               const u8 *addr)
 {
     struct mesh_path *mpath;
 
     spin_lock_bh(&tbl->walk_lock);
     mpath = rhashtable_lookup_fast(&tbl->rhead, addr, mesh_rht_params);
     if (!mpath) {
         spin_unlock_bh(&tbl->walk_lock);
         return -ENXIO;
     }
 
     __mesh_path_del(tbl, mpath);
     spin_unlock_bh(&tbl->walk_lock);
     return 0;
 }
 
 
 /**
  * mesh_path_del - delete a mesh path from the table
  *
  * @addr: dst address (ETH_ALEN length)
  * @sdata: local subif
  *
  * Returns: 0 if successful
  */
 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr)
 {
     int err;
 
     /* flush relevant mpp entries first */
     mpp_flush_by_proxy(sdata, addr);
 
     err = table_path_del(&sdata->u.mesh.mesh_paths, sdata, addr);
     sdata->u.mesh.mesh_paths_generation++;
     return err;
 }
 
 /**
  * mesh_path_tx_pending - sends pending frames in a mesh path queue
  *
  * @mpath: mesh path to activate
  *
  * Locking: the state_lock of the mpath structure must NOT be held when calling
  * this function.
  */
 void mesh_path_tx_pending(struct mesh_path *mpath)
 {
     if (mpath->flags & MESH_PATH_ACTIVE)
         ieee80211_add_pending_skbs(mpath->sdata->local,
                 &mpath->frame_queue);
 }
 
 /**
  * mesh_path_send_to_gates - sends pending frames to all known mesh gates
  *
  * @mpath: mesh path whose queue will be emptied
  *
  * If there is only one gate, the frames are transferred from the failed mpath
  * queue to that gate's queue.  If there are more than one gates, the frames
  * are copied from each gate to the next.  After frames are copied, the
  * mpath queues are emptied onto the transmission queue.
  */
 int mesh_path_send_to_gates(struct mesh_path *mpath)
 {
     struct ieee80211_sub_if_data *sdata = mpath->sdata;
     struct mesh_table *tbl;
     struct mesh_path *from_mpath = mpath;
     struct mesh_path *gate;
     bool copy = false;
 
     tbl = &sdata->u.mesh.mesh_paths;
 
     rcu_read_lock();
     hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
         if (gate->flags & MESH_PATH_ACTIVE) {
             mpath_dbg(sdata, "Forwarding to %pM\n", gate->dst);
             mesh_path_move_to_queue(gate, from_mpath, copy);
             from_mpath = gate;
             copy = true;
         } else {
             mpath_dbg(sdata,
                   "Not forwarding to %pM (flags %#x)\n",
                   gate->dst, gate->flags);
         }
     }
 
     hlist_for_each_entry_rcu(gate, &tbl->known_gates, gate_list) {
         mpath_dbg(sdata, "Sending to %pM\n", gate->dst);
         mesh_path_tx_pending(gate);
     }
     rcu_read_unlock();
 
     return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
 }
 
 /**
  * mesh_path_discard_frame - discard a frame whose path could not be resolved
  *
  * @skb: frame to discard
  * @sdata: network subif the frame was to be sent through
  *
  * Locking: the function must me called within a rcu_read_lock region
  */
 void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
                  struct sk_buff *skb)
 {
     kfree_skb(skb);
     sdata->u.mesh.mshstats.dropped_frames_no_route++;
 }
 
 /**
  * mesh_path_flush_pending - free the pending queue of a mesh path
  *
  * @mpath: mesh path whose queue has to be freed
  *
  * Locking: the function must me called within a rcu_read_lock region
  */
 void mesh_path_flush_pending(struct mesh_path *mpath)
 {
     struct sk_buff *skb;
 
     while ((skb = skb_dequeue(&mpath->frame_queue)) != NULL)
         mesh_path_discard_frame(mpath->sdata, skb);
 }
 
 /**
  * mesh_path_fix_nexthop - force a specific next hop for a mesh path
  *
  * @mpath: the mesh path to modify
  * @next_hop: the next hop to force
  *
  * Locking: this function must be called holding mpath->state_lock
  */
 void mesh_path_fix_nexthop(struct mesh_path *mpath, struct sta_info *next_hop)
 {
     spin_lock_bh(&mpath->state_lock);
     mesh_path_assign_nexthop(mpath, next_hop);
     mpath->sn = 0xffff;
     mpath->metric = 0;
     mpath->hop_count = 0;
     mpath->exp_time = 0;
     mpath->flags = MESH_PATH_FIXED | MESH_PATH_SN_VALID;
     mesh_path_activate(mpath);
     spin_unlock_bh(&mpath->state_lock);
     ewma_mesh_fail_avg_init(&next_hop->mesh->fail_avg);
     /* init it at a low value - 0 start is tricky */
     ewma_mesh_fail_avg_add(&next_hop->mesh->fail_avg, 1);
     mesh_path_tx_pending(mpath);
 }
 
 void mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
 {
     mesh_table_init(&sdata->u.mesh.mesh_paths);
     mesh_table_init(&sdata->u.mesh.mpp_paths);
 }
 
 static
 void mesh_path_tbl_expire(struct ieee80211_sub_if_data *sdata,
               struct mesh_table *tbl)
 {
     struct mesh_path *mpath;
     struct hlist_node *n;
 
     spin_lock_bh(&tbl->walk_lock);
     hlist_for_each_entry_safe(mpath, n, &tbl->walk_head, walk_list) {
         if ((!(mpath->flags & MESH_PATH_RESOLVING)) &&
             (!(mpath->flags & MESH_PATH_FIXED)) &&
              time_after(jiffies, mpath->exp_time + MESH_PATH_EXPIRE))
             __mesh_path_del(tbl, mpath);
     }
     spin_unlock_bh(&tbl->walk_lock);
 }
 
 void mesh_path_expire(struct ieee80211_sub_if_data *sdata)
 {
     mesh_path_tbl_expire(sdata, &sdata->u.mesh.mesh_paths);
     mesh_path_tbl_expire(sdata, &sdata->u.mesh.mpp_paths);
 }
 
 void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata)
 {
     mesh_table_free(&sdata->u.mesh.mesh_paths);
     mesh_table_free(&sdata->u.mesh.mpp_paths);
 }

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