text: /******************************************************************************
   *
   * Copyright(c) 2007 - 2017 Realtek Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of version 2 of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
   * more details.
   *
   *****************************************************************************/
  #define _RTW_MESH_PATHTBL_C_
  
  #ifdef CONFIG_RTW_MESH
  #include <drv_types.h>
  #include <linux/jhash.h>
  
  #ifdef PLATFORM_LINUX
  #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 0, 0))
  static void rtw_mpath_free_rcu(struct rtw_mesh_path *mpath)
  {
  	kfree_rcu(mpath, rcu);
  	rtw_mstat_update(MSTAT_TYPE_PHY, MSTAT_FREE, sizeof(struct rtw_mesh_path));
  }
  #else
  static void rtw_mpath_free_rcu_callback(rtw_rcu_head *head)
  {
  	struct rtw_mesh_path *mpath;
  
  	mpath = container_of(head, struct rtw_mesh_path, rcu);
  	rtw_mfree(mpath, sizeof(struct rtw_mesh_path));
  }
  
  static void rtw_mpath_free_rcu(struct rtw_mesh_path *mpath)
  {
  	call_rcu(&mpath->rcu, rtw_mpath_free_rcu_callback);
  }
  #endif
  #endif /* PLATFORM_LINUX */
  
  static void rtw_mesh_path_free_rcu(struct rtw_mesh_table *tbl, struct rtw_mesh_path *mpath);
  
  static u32 rtw_mesh_table_hash(const void *addr, u32 len, u32 seed)
  {
  	/* Use last four bytes of hw addr as hash index */
  	return jhash_1word(*(u32 *)(addr+2), seed);
  }
  
  static const rtw_rhashtable_params rtw_mesh_rht_params = {
  	.nelem_hint = 2,
  	.automatic_shrinking = true,
  	.key_len = ETH_ALEN,
  	.key_offset = offsetof(struct rtw_mesh_path, dst),
  	.head_offset = offsetof(struct rtw_mesh_path, rhash),
  	.hashfn = rtw_mesh_table_hash,
  };
  
  static inline bool rtw_mpath_expired(struct rtw_mesh_path *mpath)
  {
  	return (mpath->flags & RTW_MESH_PATH_ACTIVE) &&
  	       rtw_time_after(rtw_get_current_time(), mpath->exp_time) &&
  	       !(mpath->flags & RTW_MESH_PATH_FIXED);
  }
  
  static void rtw_mesh_path_rht_free(void *ptr, void *tblptr)
  {
  	struct rtw_mesh_path *mpath = ptr;
  	struct rtw_mesh_table *tbl = tblptr;
  
  	rtw_mesh_path_free_rcu(tbl, mpath);
  }
  
  static struct rtw_mesh_table *rtw_mesh_table_alloc(void)
  {
  	struct rtw_mesh_table *newtbl;
  
  	newtbl = rtw_malloc(sizeof(struct rtw_mesh_table));
  	if (!newtbl)
  		return NULL;
  
  	rtw_hlist_head_init(&newtbl->known_gates);
  	ATOMIC_SET(&newtbl->entries,  0);
  	_rtw_spinlock_init(&newtbl->gates_lock);
  
  	return newtbl;
  }
  
  static void rtw_mesh_table_free(struct rtw_mesh_table *tbl)
  {
  	rtw_rhashtable_free_and_destroy(&tbl->rhead,
  				    rtw_mesh_path_rht_free, tbl);
  	rtw_mfree(tbl, sizeof(struct rtw_mesh_table));
  }
  
  /**
   *
   * rtw_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 rtw_mesh_path_assign_nexthop(struct rtw_mesh_path *mpath, struct sta_info *sta)
  {
  	struct xmit_frame *xframe;
  	_list *list, *head;
  
  	rtw_rcu_assign_pointer(mpath->next_hop, sta);
  
  	enter_critical_bh(&mpath->frame_queue.lock);
  	head = &mpath->frame_queue.queue;
  	list = get_next(head);
  	while (rtw_end_of_queue_search(head, list) == _FALSE) {
  		xframe = LIST_CONTAINOR(list, struct xmit_frame, list);
  		list = get_next(list);
  		_rtw_memcpy(xframe->attrib.ra, sta->cmn.mac_addr, ETH_ALEN);
  	}
  
  	exit_critical_bh(&mpath->frame_queue.lock);
  }
  
  static void rtw_prepare_for_gate(struct xmit_frame *xframe, char *dst_addr,
  			     struct rtw_mesh_path *gate_mpath)
  {
  	struct pkt_attrib *attrib = &xframe->attrib;
  	char *next_hop;
  
  	if (attrib->mesh_frame_mode == MESH_UCAST_DATA)
  		attrib->mesh_frame_mode = MESH_UCAST_PX_DATA;
  
  	/* update next hop */
  	rtw_rcu_read_lock();
  	next_hop = rtw_rcu_dereference(gate_mpath->next_hop)->cmn.mac_addr;
  	_rtw_memcpy(attrib->ra, next_hop, ETH_ALEN);
  	rtw_rcu_read_unlock();
  	_rtw_memcpy(attrib->mda, dst_addr, ETH_ALEN);
  }
  
  /**
   *
   * rtw_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.
   *
   * @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 rtw_mesh_path_move_to_queue(struct rtw_mesh_path *gate_mpath,
  				    struct rtw_mesh_path *from_mpath,
  				    bool copy)
  {
  	struct xmit_frame *fskb;
  	_list *list, *head;
  	_list failq;
  	u32 failq_len;
  	_irqL flags;
  
  	if (rtw_warn_on(gate_mpath == from_mpath))
  		return;
  	if (rtw_warn_on(!gate_mpath->next_hop))
  		return;
  
  	_rtw_init_listhead(&failq);
  
  	_enter_critical_bh(&from_mpath->frame_queue.lock, &flags);
  	rtw_list_splice_init(&from_mpath->frame_queue.queue, &failq);
  	failq_len = from_mpath->frame_queue_len;
  	from_mpath->frame_queue_len = 0;
  	_exit_critical_bh(&from_mpath->frame_queue.lock, &flags);
  
  	head = &failq;
  	list = get_next(head);
  	while (rtw_end_of_queue_search(head, list) == _FALSE) {
  		if (gate_mpath->frame_queue_len >= RTW_MESH_FRAME_QUEUE_LEN) {
  			RTW_MPATH_DBG(FUNC_ADPT_FMT" mpath queue for gate %pM is full!\n"
  				, FUNC_ADPT_ARG(gate_mpath->adapter), gate_mpath->dst);
  			break;
  		}
  
  		fskb = LIST_CONTAINOR(list, struct xmit_frame, list);
  		list = get_next(list);
  
  		rtw_list_delete(&fskb->list);
  		failq_len--;
  		rtw_prepare_for_gate(fskb, gate_mpath->dst, gate_mpath);
  		_enter_critical_bh(&gate_mpath->frame_queue.lock, &flags);
  		rtw_list_insert_tail(&fskb->list, get_list_head(&gate_mpath->frame_queue));
  		gate_mpath->frame_queue_len++;
  		_exit_critical_bh(&gate_mpath->frame_queue.lock, &flags);
  
  		#if 0 /* TODO: copy */
  		skb = rtw_skb_copy(fskb);
  		if (rtw_warn_on(!skb))
  			break;
  
  		rtw_prepare_for_gate(skb, gate_mpath->dst, gate_mpath);
  		skb_queue_tail(&gate_mpath->frame_queue, skb);
  
  		if (copy)
  			continue;
  
  		__skb_unlink(fskb, &failq);
  		rtw_skb_free(fskb);
  		#endif
  	}
  
  	RTW_MPATH_DBG(FUNC_ADPT_FMT" mpath queue for gate %pM has %d frames\n"
  		, FUNC_ADPT_ARG(gate_mpath->adapter), gate_mpath->dst, gate_mpath->frame_queue_len);
  
  	if (!copy)
  		return;
  
  	_enter_critical_bh(&from_mpath->frame_queue.lock, &flags);
  	rtw_list_splice(&failq, &from_mpath->frame_queue.queue);
  	from_mpath->frame_queue_len += failq_len;
  	_exit_critical_bh(&from_mpath->frame_queue.lock, &flags);
  }
  
  
  static struct rtw_mesh_path *rtw_mpath_lookup(struct rtw_mesh_table *tbl, const u8 *dst)
  {
  	struct rtw_mesh_path *mpath;
  
  	if (!tbl)
  		return NULL;
  
  	mpath = rtw_rhashtable_lookup_fast(&tbl->rhead, dst, rtw_mesh_rht_params);
  
  	if (mpath && rtw_mpath_expired(mpath)) {
  		enter_critical_bh(&mpath->state_lock);
  		mpath->flags &= ~RTW_MESH_PATH_ACTIVE;
  		exit_critical_bh(&mpath->state_lock);
  	}
  	return mpath;
  }
  
  /**
   * rtw_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 rtw_mesh_path *
  rtw_mesh_path_lookup(_adapter *adapter, const u8 *dst)
  {
  	return rtw_mpath_lookup(adapter->mesh_info.mesh_paths, dst);
  }
  
  struct rtw_mesh_path *
  rtw_mpp_path_lookup(_adapter *adapter, const u8 *dst)
  {
  	return rtw_mpath_lookup(adapter->mesh_info.mpp_paths, dst);
  }
  
  static struct rtw_mesh_path *
  __rtw_mesh_path_lookup_by_idx(struct rtw_mesh_table *tbl, int idx)
  {
  	int i = 0, ret;
  	struct rtw_mesh_path *mpath = NULL;
  	rtw_rhashtable_iter iter;
  
  	if (!tbl)
  		return NULL;
  
  	ret = rtw_rhashtable_walk_enter(&tbl->rhead, &iter);
  	if (ret)
  		return NULL;
  
  	ret = rtw_rhashtable_walk_start(&iter);
  	if (ret && ret != -EAGAIN)
  		goto err;
  
  	while ((mpath = rtw_rhashtable_walk_next(&iter))) {
  		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
  			continue;
  		if (IS_ERR(mpath))
  			break;
  		if (i++ == idx)
  			break;
  	}
  err:
  	rtw_rhashtable_walk_stop(&iter);
  	rtw_rhashtable_walk_exit(&iter);
  
  	if (IS_ERR(mpath) || !mpath)
  		return NULL;
  
  	if (rtw_mpath_expired(mpath)) {
  		enter_critical_bh(&mpath->state_lock);
  		mpath->flags &= ~RTW_MESH_PATH_ACTIVE;
  		exit_critical_bh(&mpath->state_lock);
  	}
  	return mpath;
  }
  
  /**
   * rtw_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 rtw_mesh_path *
  rtw_mesh_path_lookup_by_idx(_adapter *adapter, int idx)
  {
  	return __rtw_mesh_path_lookup_by_idx(adapter->mesh_info.mesh_paths, idx);
  }
  
  /**
   * rtw_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 rtw_mesh_path *
  rtw_mpp_path_lookup_by_idx(_adapter *adapter, int idx)
  {
  	return __rtw_mesh_path_lookup_by_idx(adapter->mesh_info.mpp_paths, idx);
  }
  
  /**
   * rtw_mesh_path_add_gate - add the given mpath to a mesh gate to our path table
   * @mpath: gate path to add to table
   */
  int rtw_mesh_path_add_gate(struct rtw_mesh_path *mpath)
  {
  	struct rtw_mesh_cfg *mcfg;
  	struct rtw_mesh_info *minfo;
  	struct rtw_mesh_table *tbl;
  	int err, ori_num_gates;
  
  	rtw_rcu_read_lock();
  	tbl = mpath->adapter->mesh_info.mesh_paths;
  	if (!tbl) {
  		err = -ENOENT;
  		goto err_rcu;
  	}
  
  	enter_critical_bh(&mpath->state_lock);
  	mcfg = &mpath->adapter->mesh_cfg;
  	mpath->gate_timeout = rtw_get_current_time() +
  			      rtw_ms_to_systime(mcfg->path_gate_timeout_factor *
  					        mpath->gate_ann_int);
  	if (mpath->is_gate) {
  		err = -EEXIST;
  		exit_critical_bh(&mpath->state_lock);
  		goto err_rcu;
  	}
  
  	minfo = &mpath->adapter->mesh_info;
  	mpath->is_gate = true;
  	_rtw_spinlock(&tbl->gates_lock);
  	ori_num_gates = minfo->num_gates;
  	minfo->num_gates++;
  	rtw_hlist_add_head_rcu(&mpath->gate_list, &tbl->known_gates);
  	_rtw_spinunlock(&tbl->gates_lock);
  
  	exit_critical_bh(&mpath->state_lock);
  
  	if (ori_num_gates == 0)
  		update_beacon(mpath->adapter, WLAN_EID_MESH_CONFIG, NULL, _TRUE);
  
  	RTW_MPATH_DBG(
  		  FUNC_ADPT_FMT" Mesh path: Recorded new gate: %pM. %d known gates\n",
  		  FUNC_ADPT_ARG(mpath->adapter),
  		  mpath->dst, mpath->adapter->mesh_info.num_gates);
  	err = 0;
  err_rcu:
  	rtw_rcu_read_unlock();
  	return err;
  }
  
  /**
   * rtw_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
   */
  void rtw_mesh_gate_del(struct rtw_mesh_table *tbl, struct rtw_mesh_path *mpath)
  {
  	struct rtw_mesh_cfg *mcfg;
  	struct rtw_mesh_info *minfo;
  	int ori_num_gates;
  
  	rtw_lockdep_assert_held(&mpath->state_lock);
  	if (!mpath->is_gate)
  		return;
  
  	mcfg = &mpath->adapter->mesh_cfg;
  	minfo = &mpath->adapter->mesh_info;
  
  	mpath->is_gate = false;
  	enter_critical_bh(&tbl->gates_lock);
  	rtw_hlist_del_rcu(&mpath->gate_list);
  	ori_num_gates = minfo->num_gates;
  	minfo->num_gates--;
  	exit_critical_bh(&tbl->gates_lock);
  
  	if (ori_num_gates == 1)
  		update_beacon(mpath->adapter, WLAN_EID_MESH_CONFIG, NULL, _TRUE);
  
  	RTW_MPATH_DBG(
  		  FUNC_ADPT_FMT" Mesh path: Deleted gate: %pM. %d known gates\n",
  		  FUNC_ADPT_ARG(mpath->adapter),
  		  mpath->dst, mpath->adapter->mesh_info.num_gates);
  }
  
  /**
   * rtw_mesh_gate_search - search a mesh gate from the list of known gates
   * @tbl: table which holds our list of known gates
   * @addr: address of gate
   */
  bool rtw_mesh_gate_search(struct rtw_mesh_table *tbl, const u8 *addr)
  {
  	struct rtw_mesh_path *gate;
  	rtw_hlist_node *node;
  	bool exist = 0;
  
  	rtw_rcu_read_lock();
  	rtw_hlist_for_each_entry_rcu(gate, node, &tbl->known_gates, gate_list) {
  		if (_rtw_memcmp(gate->dst, addr, ETH_ALEN) == _TRUE) {
  			exist = 1;
  			break;
  		}
  	}
  
  	rtw_rcu_read_unlock();
  
  	return exist;
  }
  
  /**
   * rtw_mesh_gate_num - number of gates known to this interface
   * @sdata: subif data
   */
  int rtw_mesh_gate_num(_adapter *adapter)
  {
  	return adapter->mesh_info.num_gates;
  }
  
  static
  struct rtw_mesh_path *rtw_mesh_path_new(_adapter *adapter,
  				const u8 *dst)
  {
  	struct rtw_mesh_path *new_mpath;
  
  	new_mpath = rtw_zmalloc(sizeof(struct rtw_mesh_path));
  	if (!new_mpath)
  		return NULL;
  
  	_rtw_memcpy(new_mpath->dst, dst, ETH_ALEN);
  	_rtw_memset(new_mpath->rann_snd_addr, 0xFF, ETH_ALEN);
  	new_mpath->is_root = false;
  	new_mpath->adapter = adapter;
  	new_mpath->flags = 0;
  	new_mpath->gate_asked = false;
  	_rtw_init_queue(&new_mpath->frame_queue);
  	new_mpath->frame_queue_len = 0;
  	new_mpath->exp_time = rtw_get_current_time();
  	_rtw_spinlock_init(&new_mpath->state_lock);
  	rtw_init_timer(&new_mpath->timer, adapter, rtw_mesh_path_timer, new_mpath);
  
  	return new_mpath;
  }
  
  /**
   * rtw_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 rtw_mesh_path *rtw_mesh_path_add(_adapter *adapter,
  				const u8 *dst)
  {
  	struct rtw_mesh_table *tbl = adapter->mesh_info.mesh_paths;
  	struct rtw_mesh_path *mpath, *new_mpath;
  	int ret;
  
  	if (!tbl)
  		return ERR_PTR(-ENOTSUPP);
  
  	if (_rtw_memcmp(dst, adapter_mac_addr(adapter), ETH_ALEN) == _TRUE)
  		/* never add ourselves as neighbours */
  		return ERR_PTR(-ENOTSUPP);
  
  	if (is_multicast_mac_addr(dst))
  		return ERR_PTR(-ENOTSUPP);
  
  	if (ATOMIC_INC_UNLESS(&adapter->mesh_info.mpaths, RTW_MESH_MAX_MPATHS) == 0)
  		return ERR_PTR(-ENOSPC);
  
  	new_mpath = rtw_mesh_path_new(adapter, dst);
  	if (!new_mpath)
  		return ERR_PTR(-ENOMEM);
  
  	do {
  		ret = rtw_rhashtable_lookup_insert_fast(&tbl->rhead,
  						    &new_mpath->rhash,
  						    rtw_mesh_rht_params);
  
  		if (ret == -EEXIST)
  			mpath = rtw_rhashtable_lookup_fast(&tbl->rhead,
  						       dst,
  						       rtw_mesh_rht_params);
  
  	} while (unlikely(ret == -EEXIST && !mpath));
  
  	if (ret && ret != -EEXIST)
  		return ERR_PTR(ret);
  
  	/* At this point either new_mpath was added, or we found a
  	 * matching entry already in the table; in the latter case
  	 * free the unnecessary new entry.
  	 */
  	if (ret == -EEXIST) {
  		rtw_mfree(new_mpath, sizeof(struct rtw_mesh_path));
  		new_mpath = mpath;
  	}
  	adapter->mesh_info.mesh_paths_generation++;
  	return new_mpath;
  }
  
  int rtw_mpp_path_add(_adapter *adapter,
  		 const u8 *dst, const u8 *mpp)
  {
  	struct rtw_mesh_table *tbl = adapter->mesh_info.mpp_paths;
  	struct rtw_mesh_path *new_mpath;
  	int ret;
  
  	if (!tbl)
  		return -ENOTSUPP;
  
  	if (_rtw_memcmp(dst, adapter_mac_addr(adapter), ETH_ALEN) == _TRUE)
  		/* never add ourselves as neighbours */
  		return -ENOTSUPP;
  
  	if (is_multicast_mac_addr(dst))
  		return -ENOTSUPP;
  
  	new_mpath = rtw_mesh_path_new(adapter, dst);
  
  	if (!new_mpath)
  		return -ENOMEM;
  
  	_rtw_memcpy(new_mpath->mpp, mpp, ETH_ALEN);
  	ret = rtw_rhashtable_lookup_insert_fast(&tbl->rhead,
  					    &new_mpath->rhash,
  					    rtw_mesh_rht_params);
  
  	adapter->mesh_info.mpp_paths_generation++;
  	return ret;
  }
  
  
  /**
   * rtw_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 rtw_mesh_plink_broken(struct sta_info *sta)
  {
  	_adapter *adapter = sta->padapter;
  	struct rtw_mesh_table *tbl = adapter->mesh_info.mesh_paths;
  	static const u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  	struct rtw_mesh_path *mpath;
  	rtw_rhashtable_iter iter;
  	int ret;
  
  	if (!tbl)
  		return;
  
  	ret = rtw_rhashtable_walk_enter(&tbl->rhead, &iter);
  	if (ret)
  		return;
  
  	ret = rtw_rhashtable_walk_start(&iter);
  	if (ret && ret != -EAGAIN)
  		goto out;
  
  	while ((mpath = rtw_rhashtable_walk_next(&iter))) {
  		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
  			continue;
  		if (IS_ERR(mpath))
  			break;
  		if (rtw_rcu_access_pointer(mpath->next_hop) == sta &&
  		    mpath->flags & RTW_MESH_PATH_ACTIVE &&
  		    !(mpath->flags & RTW_MESH_PATH_FIXED)) {
  			enter_critical_bh(&mpath->state_lock);
  			mpath->flags &= ~RTW_MESH_PATH_ACTIVE;
  			++mpath->sn;
  			exit_critical_bh(&mpath->state_lock);
  			rtw_mesh_path_error_tx(adapter,
  				adapter->mesh_cfg.element_ttl,
  				mpath->dst, mpath->sn,
  				WLAN_REASON_MESH_PATH_DEST_UNREACHABLE, bcast);
  		}
  	}
  out:
  	rtw_rhashtable_walk_stop(&iter);
  	rtw_rhashtable_walk_exit(&iter);
  }
  
  static void rtw_mesh_path_free_rcu(struct rtw_mesh_table *tbl,
  			       struct rtw_mesh_path *mpath)
  {
  	_adapter *adapter = mpath->adapter;
  
  	enter_critical_bh(&mpath->state_lock);
  	mpath->flags |= RTW_MESH_PATH_RESOLVING | RTW_MESH_PATH_DELETED;
  	rtw_mesh_gate_del(tbl, mpath);
  	exit_critical_bh(&mpath->state_lock);
  	_cancel_timer_ex(&mpath->timer);
  	ATOMIC_DEC(&adapter->mesh_info.mpaths);
  	ATOMIC_DEC(&tbl->entries);
  	_rtw_spinlock_free(&mpath->state_lock);
  
  	rtw_mesh_path_flush_pending(mpath);
  
  	rtw_mpath_free_rcu(mpath);
  }
  
  static void __rtw_mesh_path_del(struct rtw_mesh_table *tbl, struct rtw_mesh_path *mpath)
  {
  	rtw_rhashtable_remove_fast(&tbl->rhead, &mpath->rhash, rtw_mesh_rht_params);
  	rtw_mesh_path_free_rcu(tbl, mpath);
  }
  
  /**
   * rtw_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 rtw_mesh_path_flush_by_nexthop(struct sta_info *sta)
  {
  	_adapter *adapter = sta->padapter;
  	struct rtw_mesh_table *tbl = adapter->mesh_info.mesh_paths;
  	struct rtw_mesh_path *mpath;
  	rtw_rhashtable_iter iter;
  	int ret;
  
  	if (!tbl)
  		return;
  
  	ret = rtw_rhashtable_walk_enter(&tbl->rhead, &iter);
  	if (ret)
  		return;
  
  	ret = rtw_rhashtable_walk_start(&iter);
  	if (ret && ret != -EAGAIN)
  		goto out;
  
  	while ((mpath = rtw_rhashtable_walk_next(&iter))) {
  		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
  			continue;
  		if (IS_ERR(mpath))
  			break;
  
  		if (rtw_rcu_access_pointer(mpath->next_hop) == sta)
  			__rtw_mesh_path_del(tbl, mpath);
  	}
  out:
  	rtw_rhashtable_walk_stop(&iter);
  	rtw_rhashtable_walk_exit(&iter);
  }
  
  static void rtw_mpp_flush_by_proxy(_adapter *adapter,
  			       const u8 *proxy)
  {
  	struct rtw_mesh_table *tbl = adapter->mesh_info.mpp_paths;
  	struct rtw_mesh_path *mpath;
  	rtw_rhashtable_iter iter;
  	int ret;
  
  	if (!tbl)
  		return;
  
  	ret = rtw_rhashtable_walk_enter(&tbl->rhead, &iter);
  	if (ret)
  		return;
  
  	ret = rtw_rhashtable_walk_start(&iter);
  	if (ret && ret != -EAGAIN)
  		goto out;
  
  	while ((mpath = rtw_rhashtable_walk_next(&iter))) {
  		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
  			continue;
  		if (IS_ERR(mpath))
  			break;
  
  		if (_rtw_memcmp(mpath->mpp, proxy, ETH_ALEN) == _TRUE)
  			__rtw_mesh_path_del(tbl, mpath);
  	}
  out:
  	rtw_rhashtable_walk_stop(&iter);
  	rtw_rhashtable_walk_exit(&iter);
  }
  
  static void rtw_table_flush_by_iface(struct rtw_mesh_table *tbl)
  {
  	struct rtw_mesh_path *mpath;
  	rtw_rhashtable_iter iter;
  	int ret;
  
  	if (!tbl)
  		return;
  	
  	ret = rtw_rhashtable_walk_enter(&tbl->rhead, &iter);
  	if (ret)
  		return;
  
  	ret = rtw_rhashtable_walk_start(&iter);
  	if (ret && ret != -EAGAIN)
  		goto out;
  
  	while ((mpath = rtw_rhashtable_walk_next(&iter))) {
  		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
  			continue;
  		if (IS_ERR(mpath))
  			break;
  		__rtw_mesh_path_del(tbl, mpath);
  	}
  out:
  	rtw_rhashtable_walk_stop(&iter);
  	rtw_rhashtable_walk_exit(&iter);
  }
  
  /**
   * rtw_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 rtw_mesh_path_flush_by_iface(_adapter *adapter)
  {
  	rtw_table_flush_by_iface(adapter->mesh_info.mesh_paths);
  	rtw_table_flush_by_iface(adapter->mesh_info.mpp_paths);
  }
  
  /**
   * rtw_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 rtw_table_path_del(struct rtw_mesh_table *tbl,
  			  const u8 *addr)
  {
  	struct rtw_mesh_path *mpath;
  
  	if (!tbl)
  		return -ENXIO;
  
  	rtw_rcu_read_lock();
  	mpath = rtw_rhashtable_lookup_fast(&tbl->rhead, addr, rtw_mesh_rht_params);
  	if (!mpath) {
  		rtw_rcu_read_unlock();
  		return -ENXIO;
  	}
  
  	__rtw_mesh_path_del(tbl, mpath);
  	rtw_rcu_read_unlock();
  	return 0;
  }
  
  
  /**
   * rtw_mesh_path_del - delete a mesh path from the table
   *
   * @addr: dst address (ETH_ALEN length)
   * @sdata: local subif
   *
   * Returns: 0 if successful
   */
  int rtw_mesh_path_del(_adapter *adapter, const u8 *addr)
  {
  	int err;
  
  	/* flush relevant mpp entries first */
  	rtw_mpp_flush_by_proxy(adapter, addr);
  
  	err = rtw_table_path_del(adapter->mesh_info.mesh_paths, addr);
  	adapter->mesh_info.mesh_paths_generation++;
  	return err;
  }
  
  /**
   * rtw_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 rtw_mesh_path_tx_pending(struct rtw_mesh_path *mpath)
  {
  	if (mpath->flags & RTW_MESH_PATH_ACTIVE) {
  		struct rtw_mesh_info *minfo = &mpath->adapter->mesh_info;
  		_list q;
  		u32 q_len = 0;
  
  		_rtw_init_listhead(&q);
  
  		/* move to local queue */
  		enter_critical_bh(&mpath->frame_queue.lock);
  		if (mpath->frame_queue_len) {
  			rtw_list_splice_init(&mpath->frame_queue.queue, &q);
  			q_len = mpath->frame_queue_len;
  			mpath->frame_queue_len = 0;
  		}
  		exit_critical_bh(&mpath->frame_queue.lock);
  
  		if (q_len) {
  			/* move to mpath_tx_queue */
  			enter_critical_bh(&minfo->mpath_tx_queue.lock);
  			rtw_list_splice_tail(&q, &minfo->mpath_tx_queue.queue);
  			minfo->mpath_tx_queue_len += q_len;
  			exit_critical_bh(&minfo->mpath_tx_queue.lock);
  
  			/* schedule mpath_tx_tasklet */
  			tasklet_hi_schedule(&minfo->mpath_tx_tasklet);
  		}
  	}
  }
  
  /**
   * rtw_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 rtw_mesh_path_send_to_gates(struct rtw_mesh_path *mpath)
  {
  	_adapter *adapter = mpath->adapter;
  	struct rtw_mesh_table *tbl;
  	struct rtw_mesh_path *from_mpath = mpath;
  	struct rtw_mesh_path *gate;
  	bool copy = false;
  	rtw_hlist_node *node;
  
  	tbl = adapter->mesh_info.mesh_paths;
  	if (!tbl)
  		return 0;
  
  	rtw_rcu_read_lock();
  	rtw_hlist_for_each_entry_rcu(gate, node, &tbl->known_gates, gate_list) {
  		if (gate->flags & RTW_MESH_PATH_ACTIVE) {
  			RTW_MPATH_DBG(FUNC_ADPT_FMT" Forwarding to %pM\n",
  				FUNC_ADPT_ARG(adapter), gate->dst);
  			rtw_mesh_path_move_to_queue(gate, from_mpath, copy);
  			from_mpath = gate;
  			copy = true;
  		} else {
  			RTW_MPATH_DBG(
  				  FUNC_ADPT_FMT" Not forwarding to %pM (flags %#x)\n",
  				  FUNC_ADPT_ARG(adapter), gate->dst, gate->flags);
  		}
  	}
  
  	rtw_hlist_for_each_entry_rcu(gate, node, &tbl->known_gates, gate_list) {
  		RTW_MPATH_DBG(FUNC_ADPT_FMT" Sending to %pM\n",
  			FUNC_ADPT_ARG(adapter), gate->dst);
  		rtw_mesh_path_tx_pending(gate);
  	}
  	rtw_rcu_read_unlock();
  
  	return (from_mpath == mpath) ? -EHOSTUNREACH : 0;
  }
  
  /**
   * rtw_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 rtw_mesh_path_discard_frame(_adapter *adapter,
  			     struct xmit_frame *xframe)
  {
  	rtw_free_xmitframe(&adapter->xmitpriv, xframe);
  	adapter->mesh_info.mshstats.dropped_frames_no_route++;
  }
  
  /**
   * rtw_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 rtw_mesh_path_flush_pending(struct rtw_mesh_path *mpath)
  {
  	struct xmit_frame *xframe;
  	_list *list, *head;
  	_list tmp;
  
  	_rtw_init_listhead(&tmp);
  
  	enter_critical_bh(&mpath->frame_queue.lock);
  	rtw_list_splice_init(&mpath->frame_queue.queue, &tmp);
  	mpath->frame_queue_len = 0;
  	exit_critical_bh(&mpath->frame_queue.lock);
  
  	head = &tmp;
  	list = get_next(head);
  	while (rtw_end_of_queue_search(head, list) == _FALSE) {
  		xframe = LIST_CONTAINOR(list, struct xmit_frame, list);
  		list = get_next(list);
  		rtw_list_delete(&xframe->list);
  		rtw_mesh_path_discard_frame(mpath->adapter, xframe);
  	}
  }
  
  /**
   * rtw_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 rtw_mesh_path_fix_nexthop(struct rtw_mesh_path *mpath, struct sta_info *next_hop)
  {
  	enter_critical_bh(&mpath->state_lock);
  	rtw_mesh_path_assign_nexthop(mpath, next_hop);
  	mpath->sn = 0xffff;
  	mpath->metric = 0;
  	mpath->hop_count = 0;
  	mpath->exp_time = 0;
  	mpath->flags = RTW_MESH_PATH_FIXED | RTW_MESH_PATH_SN_VALID;
  	rtw_mesh_path_activate(mpath);
  	exit_critical_bh(&mpath->state_lock);
  	rtw_ewma_err_rate_init(&next_hop->metrics.err_rate);
  	/* init it at a low value - 0 start is tricky */
  	rtw_ewma_err_rate_add(&next_hop->metrics.err_rate, 1);
  	rtw_mesh_path_tx_pending(mpath);
  }
  
  int rtw_mesh_pathtbl_init(_adapter *adapter)
  {
  	struct rtw_mesh_table *tbl_path, *tbl_mpp;
  	int ret;
  
  	tbl_path = rtw_mesh_table_alloc();
  	if (!tbl_path)
  		return -ENOMEM;
  
  	tbl_mpp = rtw_mesh_table_alloc();
  	if (!tbl_mpp) {
  		ret = -ENOMEM;
  		goto free_path;
  	}
  
  	rtw_rhashtable_init(&tbl_path->rhead, &rtw_mesh_rht_params);
  	rtw_rhashtable_init(&tbl_mpp->rhead, &rtw_mesh_rht_params);
  
  	adapter->mesh_info.mesh_paths = tbl_path;
  	adapter->mesh_info.mpp_paths = tbl_mpp;
  
  	return 0;
  
  free_path:
  	rtw_mesh_table_free(tbl_path);
  	return ret;
  }
  
  static
  void rtw_mesh_path_tbl_expire(_adapter *adapter,
  			  struct rtw_mesh_table *tbl)
  {
  	struct rtw_mesh_path *mpath;
  	rtw_rhashtable_iter iter;
  	int ret;
  
  	if (!tbl)
  		return;
  
  	ret = rtw_rhashtable_walk_enter(&tbl->rhead, &iter);
  	if (ret)
  		return;
  
  	ret = rtw_rhashtable_walk_start(&iter);
  	if (ret && ret != -EAGAIN)
  		goto out;
  
  	while ((mpath = rtw_rhashtable_walk_next(&iter))) {
  		if (IS_ERR(mpath) && PTR_ERR(mpath) == -EAGAIN)
  			continue;
  		if (IS_ERR(mpath))
  			break;
  		if ((!(mpath->flags & RTW_MESH_PATH_RESOLVING)) &&
  		    (!(mpath->flags & RTW_MESH_PATH_FIXED)) &&
  		     rtw_time_after(rtw_get_current_time(), mpath->exp_time + RTW_MESH_PATH_EXPIRE))
  			__rtw_mesh_path_del(tbl, mpath);
  
  		if (mpath->is_gate &&  /* need not to deal with non-gate case */
  		    rtw_time_after(rtw_get_current_time(), mpath->gate_timeout)) {
  			RTW_MPATH_DBG(FUNC_ADPT_FMT"mpath [%pM] expired systime is %lu systime is %lu\n",
  				      FUNC_ADPT_ARG(adapter), mpath->dst,
  				      mpath->gate_timeout, rtw_get_current_time());
  			enter_critical_bh(&mpath->state_lock);
  			if (mpath->gate_asked) { /* asked gate before */
  				rtw_mesh_gate_del(tbl, mpath);
  				exit_critical_bh(&mpath->state_lock);
  			} else {
  				mpath->gate_asked = true;
  				mpath->gate_timeout = rtw_get_current_time() + rtw_ms_to_systime(mpath->gate_ann_int);
  				exit_critical_bh(&mpath->state_lock);
  				rtw_mesh_queue_preq(mpath, RTW_PREQ_Q_F_START | RTW_PREQ_Q_F_REFRESH);
  				RTW_MPATH_DBG(FUNC_ADPT_FMT"mpath [%pM] ask mesh gate existence (is_root=%d)\n",
  				      FUNC_ADPT_ARG(adapter), mpath->dst, mpath->is_root);
  			}
  		}
  	}
  
  out:
  	rtw_rhashtable_walk_stop(&iter);
  	rtw_rhashtable_walk_exit(&iter);
  }
  
  void rtw_mesh_path_expire(_adapter *adapter)
  {
  	rtw_mesh_path_tbl_expire(adapter, adapter->mesh_info.mesh_paths);
  	rtw_mesh_path_tbl_expire(adapter, adapter->mesh_info.mpp_paths);
  }
  
  void rtw_mesh_pathtbl_unregister(_adapter *adapter)
  {
  	if (adapter->mesh_info.mesh_paths) {
  		rtw_mesh_table_free(adapter->mesh_info.mesh_paths);
  		adapter->mesh_info.mesh_paths = NULL;
  	}
  
  	if (adapter->mesh_info.mpp_paths) {
  		rtw_mesh_table_free(adapter->mesh_info.mpp_paths);
  		adapter->mesh_info.mpp_paths = NULL;
  	}
  }
  #endif /* CONFIG_RTW_MESH */
  
  