/*

   * Copyright (c) 2008, 2009 open80211s Ltd.

   * Authors:    Luis Carlos Cobo <luisca@cozybit.com>
   * 	       Javier Cardona <javier@cozybit.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */

  #include <linux/slab.h>

  #include <asm/unaligned.h>

  #include "ieee80211_i.h"
  #include "mesh.h"

  #include "driver-ops.h"

  static int mesh_allocated;

  static struct kmem_cache *rm_cache;

  bool mesh_action_is_path_sel(struct ieee80211_mgmt *mgmt)
  {
  	return (mgmt->u.action.u.mesh_action.action_code ==
  			WLAN_MESH_ACTION_HWMP_PATH_SELECTION);
  }

  void ieee80211s_init(void)
  {

  	mesh_allocated = 1;
  	rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),
  				     0, 0, NULL);
  }
  
  void ieee80211s_stop(void)
  {

  	if (!mesh_allocated)
  		return;

  	kmem_cache_destroy(rm_cache);
  }

  static void ieee80211_mesh_housekeeping_timer(unsigned long data)
  {
  	struct ieee80211_sub_if_data *sdata = (void *) data;
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	set_bit(MESH_WORK_HOUSEKEEPING, &ifmsh->wrkq_flags);

  	ieee80211_queue_work(&local->hw, &sdata->work);

  }

  /**
   * mesh_matches_local - check if the config of a mesh point matches ours
   *

   * @sdata: local mesh subif

   * @ie: information elements of a management frame from the mesh peer

   *
   * This function checks if the mesh configuration of a mesh point matches the
   * local mesh configuration, i.e. if both nodes belong to the same mesh network.
   */

  bool mesh_matches_local(struct ieee80211_sub_if_data *sdata,
  			struct ieee802_11_elems *ie)

  {

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	u32 basic_rates = 0;

  	struct cfg80211_chan_def sta_chan_def;

  	struct ieee80211_supported_band *sband;

  	/*
  	 * As support for each feature is added, check for matching
  	 * - On mesh config capabilities
  	 *   - Power Save Support En
  	 *   - Sync support enabled
  	 *   - Sync support active
  	 *   - Sync support required from peer
  	 *   - MDA enabled
  	 * - Power management control on fc
  	 */

  	if (!(ifmsh->mesh_id_len == ie->mesh_id_len &&
  	     memcmp(ifmsh->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 &&
  	     (ifmsh->mesh_pp_id == ie->mesh_config->meshconf_psel) &&
  	     (ifmsh->mesh_pm_id == ie->mesh_config->meshconf_pmetric) &&
  	     (ifmsh->mesh_cc_id == ie->mesh_config->meshconf_congest) &&
  	     (ifmsh->mesh_sp_id == ie->mesh_config->meshconf_synch) &&
  	     (ifmsh->mesh_auth_id == ie->mesh_config->meshconf_auth)))

  		return false;

  	sband = ieee80211_get_sband(sdata);
  	if (!sband)
  		return false;
  
  	ieee80211_sta_get_rates(sdata, ie, sband->band,

  				&basic_rates);

  	if (sdata->vif.bss_conf.basic_rates != basic_rates)

  		return false;

  	cfg80211_chandef_create(&sta_chan_def, sdata->vif.bss_conf.chandef.chan,
  				NL80211_CHAN_NO_HT);
  	ieee80211_chandef_ht_oper(ie->ht_operation, &sta_chan_def);
  	ieee80211_chandef_vht_oper(ie->vht_operation, &sta_chan_def);

  	if (!cfg80211_chandef_compatible(&sdata->vif.bss_conf.chandef,
  					 &sta_chan_def))

  		return false;

  	return true;

  }
  
  /**
   * mesh_peer_accepts_plinks - check if an mp is willing to establish peer links
   *
   * @ie: information elements of a management frame from the mesh peer

   */

  bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie)

  {

  	return (ie->mesh_config->meshconf_cap &

  			IEEE80211_MESHCONF_CAPAB_ACCEPT_PLINKS) != 0;

  }
  
  /**

   * mesh_accept_plinks_update - update accepting_plink in local mesh beacons

   *

   * @sdata: mesh interface in which mesh beacons are going to be updated

   *
   * Returns: beacon changed flag if the beacon content changed.

   */

  u32 mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata)

  {

  	bool free_plinks;

  	u32 changed = 0;

  
  	/* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,
  	 * the mesh interface might be able to establish plinks with peers that

  	 * are already on the table but are not on PLINK_ESTAB state. However,
  	 * in general the mesh interface is not accepting peer link requests
  	 * from new peers, and that must be reflected in the beacon

  	 */
  	free_plinks = mesh_plink_availables(sdata);

  	if (free_plinks != sdata->u.mesh.accepting_plinks) {
  		sdata->u.mesh.accepting_plinks = free_plinks;
  		changed = BSS_CHANGED_BEACON;
  	}
  
  	return changed;

  }

  /*
   * mesh_sta_cleanup - clean up any mesh sta state
   *
   * @sta: mesh sta to clean up.
   */
  void mesh_sta_cleanup(struct sta_info *sta)
  {
  	struct ieee80211_sub_if_data *sdata = sta->sdata;

  	u32 changed = mesh_plink_deactivate(sta);

  	if (changed)

  		ieee80211_mbss_info_change_notify(sdata, changed);

  }

  int mesh_rmc_init(struct ieee80211_sub_if_data *sdata)

  {

  	int i;

  	sdata->u.mesh.rmc = kmalloc(sizeof(struct mesh_rmc), GFP_KERNEL);
  	if (!sdata->u.mesh.rmc)

  		return -ENOMEM;

  	sdata->u.mesh.rmc->idx_mask = RMC_BUCKETS - 1;

  	for (i = 0; i < RMC_BUCKETS; i++)

  		INIT_HLIST_HEAD(&sdata->u.mesh.rmc->bucket[i]);

  	return 0;
  }

  void mesh_rmc_free(struct ieee80211_sub_if_data *sdata)

  {

  	struct mesh_rmc *rmc = sdata->u.mesh.rmc;

  	struct rmc_entry *p;
  	struct hlist_node *n;

  	int i;

  	if (!sdata->u.mesh.rmc)

  		return;

  	for (i = 0; i < RMC_BUCKETS; i++) {

  		hlist_for_each_entry_safe(p, n, &rmc->bucket[i], list) {
  			hlist_del(&p->list);

  			kmem_cache_free(rm_cache, p);
  		}

  	}

  
  	kfree(rmc);

  	sdata->u.mesh.rmc = NULL;

  }
  
  /**
   * mesh_rmc_check - Check frame in recent multicast cache and add if absent.
   *

   * @sdata:	interface

   * @sa:		source address
   * @mesh_hdr:	mesh_header
   *
   * Returns: 0 if the frame is not in the cache, nonzero otherwise.
   *
   * Checks using the source address and the mesh sequence number if we have
   * received this frame lately. If the frame is not in the cache, it is added to
   * it.
   */

  int mesh_rmc_check(struct ieee80211_sub_if_data *sdata,
  		   const u8 *sa, struct ieee80211s_hdr *mesh_hdr)

  {

  	struct mesh_rmc *rmc = sdata->u.mesh.rmc;

  	u32 seqnum = 0;
  	int entries = 0;
  	u8 idx;

  	struct rmc_entry *p;
  	struct hlist_node *n;

  	if (!rmc)
  		return -1;

  	/* Don't care about endianness since only match matters */

  	memcpy(&seqnum, &mesh_hdr->seqnum, sizeof(mesh_hdr->seqnum));
  	idx = le32_to_cpu(mesh_hdr->seqnum) & rmc->idx_mask;

  	hlist_for_each_entry_safe(p, n, &rmc->bucket[idx], list) {

  		++entries;
  		if (time_after(jiffies, p->exp_time) ||

  		    entries == RMC_QUEUE_MAX_LEN) {

  			hlist_del(&p->list);

  			kmem_cache_free(rm_cache, p);
  			--entries;

  		} else if ((seqnum == p->seqnum) && ether_addr_equal(sa, p->sa))

  			return -1;
  	}
  
  	p = kmem_cache_alloc(rm_cache, GFP_ATOMIC);

  	if (!p)

  		return 0;

  	p->seqnum = seqnum;
  	p->exp_time = jiffies + RMC_TIMEOUT;
  	memcpy(p->sa, sa, ETH_ALEN);

  	hlist_add_head(&p->list, &rmc->bucket[idx]);

  	return 0;
  }

  int mesh_add_meshconf_ie(struct ieee80211_sub_if_data *sdata,
  			 struct sk_buff *skb)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	u8 *pos, neighbors;
  	u8 meshconf_len = sizeof(struct ieee80211_meshconf_ie);
  
  	if (skb_tailroom(skb) < 2 + meshconf_len)
  		return -ENOMEM;
  
  	pos = skb_put(skb, 2 + meshconf_len);
  	*pos++ = WLAN_EID_MESH_CONFIG;
  	*pos++ = meshconf_len;

  	/* save a pointer for quick updates in pre-tbtt */
  	ifmsh->meshconf_offset = pos - skb->data;

  	/* Active path selection protocol ID */
  	*pos++ = ifmsh->mesh_pp_id;
  	/* Active path selection metric ID   */
  	*pos++ = ifmsh->mesh_pm_id;
  	/* Congestion control mode identifier */
  	*pos++ = ifmsh->mesh_cc_id;
  	/* Synchronization protocol identifier */
  	*pos++ = ifmsh->mesh_sp_id;
  	/* Authentication Protocol identifier */
  	*pos++ = ifmsh->mesh_auth_id;
  	/* Mesh Formation Info - number of neighbors */

  	neighbors = atomic_read(&ifmsh->estab_plinks);

  	neighbors = min_t(int, neighbors, IEEE80211_MAX_MESH_PEERINGS);

  	*pos++ = neighbors << 1;
  	/* Mesh capability */

  	*pos = 0x00;
  	*pos |= ifmsh->mshcfg.dot11MeshForwarding ?
  			IEEE80211_MESHCONF_CAPAB_FORWARDING : 0x00;

  	*pos |= ifmsh->accepting_plinks ?

  			IEEE80211_MESHCONF_CAPAB_ACCEPT_PLINKS : 0x00;

  	/* Mesh PS mode. See IEEE802.11-2012 8.4.2.100.8 */
  	*pos |= ifmsh->ps_peers_deep_sleep ?

  			IEEE80211_MESHCONF_CAPAB_POWER_SAVE_LEVEL : 0x00;

  	return 0;
  }

  int mesh_add_meshid_ie(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	u8 *pos;
  
  	if (skb_tailroom(skb) < 2 + ifmsh->mesh_id_len)
  		return -ENOMEM;
  
  	pos = skb_put(skb, 2 + ifmsh->mesh_id_len);
  	*pos++ = WLAN_EID_MESH_ID;
  	*pos++ = ifmsh->mesh_id_len;
  	if (ifmsh->mesh_id_len)
  		memcpy(pos, ifmsh->mesh_id, ifmsh->mesh_id_len);
  
  	return 0;
  }

  static int mesh_add_awake_window_ie(struct ieee80211_sub_if_data *sdata,
  				    struct sk_buff *skb)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	u8 *pos;
  
  	/* see IEEE802.11-2012 13.14.6 */
  	if (ifmsh->ps_peers_light_sleep == 0 &&
  	    ifmsh->ps_peers_deep_sleep == 0 &&
  	    ifmsh->nonpeer_pm == NL80211_MESH_POWER_ACTIVE)
  		return 0;
  
  	if (skb_tailroom(skb) < 4)
  		return -ENOMEM;
  
  	pos = skb_put(skb, 2 + 2);
  	*pos++ = WLAN_EID_MESH_AWAKE_WINDOW;
  	*pos++ = 2;
  	put_unaligned_le16(ifmsh->mshcfg.dot11MeshAwakeWindowDuration, pos);
  
  	return 0;
  }

  int mesh_add_vendor_ies(struct ieee80211_sub_if_data *sdata,
  			struct sk_buff *skb)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	u8 offset, len;
  	const u8 *data;
  
  	if (!ifmsh->ie || !ifmsh->ie_len)
  		return 0;
  
  	/* fast-forward to vendor IEs */
  	offset = ieee80211_ie_split_vendor(ifmsh->ie, ifmsh->ie_len, 0);

  	if (offset < ifmsh->ie_len) {

  		len = ifmsh->ie_len - offset;
  		data = ifmsh->ie + offset;
  		if (skb_tailroom(skb) < len)
  			return -ENOMEM;

  		skb_put_data(skb, data, len);

  	}
  
  	return 0;
  }

  int mesh_add_rsn_ie(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	u8 len = 0;
  	const u8 *data;
  
  	if (!ifmsh->ie || !ifmsh->ie_len)
  		return 0;
  
  	/* find RSN IE */

  	data = cfg80211_find_ie(WLAN_EID_RSN, ifmsh->ie, ifmsh->ie_len);
  	if (!data)
  		return 0;

  	len = data[1] + 2;
  
  	if (skb_tailroom(skb) < len)
  		return -ENOMEM;

  	skb_put_data(skb, data, len);

  
  	return 0;
  }

  static int mesh_add_ds_params_ie(struct ieee80211_sub_if_data *sdata,
  				 struct sk_buff *skb)

  {

  	struct ieee80211_chanctx_conf *chanctx_conf;
  	struct ieee80211_channel *chan;

  	u8 *pos;

  	if (skb_tailroom(skb) < 3)
  		return -ENOMEM;

  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  	if (WARN_ON(!chanctx_conf)) {
  		rcu_read_unlock();
  		return -EINVAL;
  	}

  	chan = chanctx_conf->def.chan;

  	rcu_read_unlock();

  	pos = skb_put(skb, 2 + 1);
  	*pos++ = WLAN_EID_DS_PARAMS;
  	*pos++ = 1;
  	*pos++ = ieee80211_frequency_to_channel(chan->center_freq);

  	return 0;

  }

  int mesh_add_ht_cap_ie(struct ieee80211_sub_if_data *sdata,
  		       struct sk_buff *skb)

  {

  	struct ieee80211_supported_band *sband;
  	u8 *pos;

  	sband = ieee80211_get_sband(sdata);
  	if (!sband)
  		return -EINVAL;

  	if (!sband->ht_cap.ht_supported ||

  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_5 ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_10)

  		return 0;
  
  	if (skb_tailroom(skb) < 2 + sizeof(struct ieee80211_ht_cap))
  		return -ENOMEM;
  
  	pos = skb_put(skb, 2 + sizeof(struct ieee80211_ht_cap));

  	ieee80211_ie_build_ht_cap(pos, &sband->ht_cap, sband->ht_cap.cap);

  
  	return 0;
  }

  int mesh_add_ht_oper_ie(struct ieee80211_sub_if_data *sdata,
  			struct sk_buff *skb)

  {
  	struct ieee80211_local *local = sdata->local;

  	struct ieee80211_chanctx_conf *chanctx_conf;
  	struct ieee80211_channel *channel;

  	struct ieee80211_supported_band *sband;
  	struct ieee80211_sta_ht_cap *ht_cap;

  	u8 *pos;

  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  	if (WARN_ON(!chanctx_conf)) {
  		rcu_read_unlock();
  		return -EINVAL;
  	}

  	channel = chanctx_conf->def.chan;

  	rcu_read_unlock();
  
  	sband = local->hw.wiphy->bands[channel->band];
  	ht_cap = &sband->ht_cap;

  	if (!ht_cap->ht_supported ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_5 ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_10)

  		return 0;

  	if (skb_tailroom(skb) < 2 + sizeof(struct ieee80211_ht_operation))

  		return -ENOMEM;

  	pos = skb_put(skb, 2 + sizeof(struct ieee80211_ht_operation));

  	ieee80211_ie_build_ht_oper(pos, ht_cap, &sdata->vif.bss_conf.chandef,

  				   sdata->vif.bss_conf.ht_operation_mode,
  				   false);

  
  	return 0;
  }

  int mesh_add_vht_cap_ie(struct ieee80211_sub_if_data *sdata,
  			struct sk_buff *skb)
  {

  	struct ieee80211_supported_band *sband;
  	u8 *pos;

  	sband = ieee80211_get_sband(sdata);
  	if (!sband)
  		return -EINVAL;

  	if (!sband->vht_cap.vht_supported ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_5 ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_10)
  		return 0;
  
  	if (skb_tailroom(skb) < 2 + sizeof(struct ieee80211_vht_cap))
  		return -ENOMEM;
  
  	pos = skb_put(skb, 2 + sizeof(struct ieee80211_vht_cap));
  	ieee80211_ie_build_vht_cap(pos, &sband->vht_cap, sband->vht_cap.cap);
  
  	return 0;
  }
  
  int mesh_add_vht_oper_ie(struct ieee80211_sub_if_data *sdata,
  			 struct sk_buff *skb)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_chanctx_conf *chanctx_conf;
  	struct ieee80211_channel *channel;
  	struct ieee80211_supported_band *sband;
  	struct ieee80211_sta_vht_cap *vht_cap;
  	u8 *pos;
  
  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  	if (WARN_ON(!chanctx_conf)) {
  		rcu_read_unlock();
  		return -EINVAL;
  	}
  	channel = chanctx_conf->def.chan;
  	rcu_read_unlock();
  
  	sband = local->hw.wiphy->bands[channel->band];
  	vht_cap = &sband->vht_cap;
  
  	if (!vht_cap->vht_supported ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_5 ||
  	    sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_10)
  		return 0;
  
  	if (skb_tailroom(skb) < 2 + sizeof(struct ieee80211_vht_operation))
  		return -ENOMEM;
  
  	pos = skb_put(skb, 2 + sizeof(struct ieee80211_vht_operation));
  	ieee80211_ie_build_vht_oper(pos, vht_cap,
  				    &sdata->vif.bss_conf.chandef);
  
  	return 0;
  }

  static void ieee80211_mesh_path_timer(unsigned long data)
  {
  	struct ieee80211_sub_if_data *sdata =
  		(struct ieee80211_sub_if_data *) data;

  	ieee80211_queue_work(&sdata->local->hw, &sdata->work);

  }

  static void ieee80211_mesh_path_root_timer(unsigned long data)
  {
  	struct ieee80211_sub_if_data *sdata =
  		(struct ieee80211_sub_if_data *) data;
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  
  	set_bit(MESH_WORK_ROOT, &ifmsh->wrkq_flags);

  	ieee80211_queue_work(&sdata->local->hw, &sdata->work);

  }

  void ieee80211_mesh_root_setup(struct ieee80211_if_mesh *ifmsh)
  {

  	if (ifmsh->mshcfg.dot11MeshHWMPRootMode > IEEE80211_ROOTMODE_ROOT)

  		set_bit(MESH_WORK_ROOT, &ifmsh->wrkq_flags);
  	else {
  		clear_bit(MESH_WORK_ROOT, &ifmsh->wrkq_flags);
  		/* stop running timer */
  		del_timer_sync(&ifmsh->mesh_path_root_timer);
  	}
  }

  /**

   * ieee80211_fill_mesh_addresses - fill addresses of a locally originated mesh frame

   * @hdr:	802.11 frame header

   * @fc:		frame control field
   * @meshda:	destination address in the mesh
   * @meshsa:	source address address in the mesh.  Same as TA, as frame is
   *              locally originated.
   *
   * Return the length of the 802.11 (does not include a mesh control header)
   */

  int ieee80211_fill_mesh_addresses(struct ieee80211_hdr *hdr, __le16 *fc,
  				  const u8 *meshda, const u8 *meshsa)
  {

  	if (is_multicast_ether_addr(meshda)) {
  		*fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
  		/* DA TA SA */
  		memcpy(hdr->addr1, meshda, ETH_ALEN);
  		memcpy(hdr->addr2, meshsa, ETH_ALEN);
  		memcpy(hdr->addr3, meshsa, ETH_ALEN);
  		return 24;
  	} else {

  		*fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);

  		/* RA TA DA SA */

  		eth_zero_addr(hdr->addr1);   /* RA is resolved later */

  		memcpy(hdr->addr2, meshsa, ETH_ALEN);
  		memcpy(hdr->addr3, meshda, ETH_ALEN);
  		memcpy(hdr->addr4, meshsa, ETH_ALEN);
  		return 30;
  	}
  }
  
  /**

   * ieee80211_new_mesh_header - create a new mesh header

   * @sdata:	mesh interface to be used

   * @meshhdr:    uninitialized mesh header

   * @addr4or5:   1st address in the ae header, which may correspond to address 4
   *              (if addr6 is NULL) or address 5 (if addr6 is present). It may
   *              be NULL.
   * @addr6:	2nd address in the ae header, which corresponds to addr6 of the
   *              mesh frame

   *
   * Return the header length.
   */

  unsigned int ieee80211_new_mesh_header(struct ieee80211_sub_if_data *sdata,
  				       struct ieee80211s_hdr *meshhdr,
  				       const char *addr4or5, const char *addr6)

  {

  	if (WARN_ON(!addr4or5 && addr6))
  		return 0;

  	memset(meshhdr, 0, sizeof(*meshhdr));

  	meshhdr->ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;

  
  	/* FIXME: racy -- TX on multiple queues can be concurrent */

  	put_unaligned(cpu_to_le32(sdata->u.mesh.mesh_seqnum), &meshhdr->seqnum);
  	sdata->u.mesh.mesh_seqnum++;

  	if (addr4or5 && !addr6) {

  		meshhdr->flags |= MESH_FLAGS_AE_A4;

  		memcpy(meshhdr->eaddr1, addr4or5, ETH_ALEN);

  		return 2 * ETH_ALEN;

  	} else if (addr4or5 && addr6) {

  		meshhdr->flags |= MESH_FLAGS_AE_A5_A6;

  		memcpy(meshhdr->eaddr1, addr4or5, ETH_ALEN);
  		memcpy(meshhdr->eaddr2, addr6, ETH_ALEN);

  		return 3 * ETH_ALEN;

  	}

  
  	return ETH_ALEN;

  }

  static void ieee80211_mesh_housekeeping(struct ieee80211_sub_if_data *sdata)

  {

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	u32 changed;

  	if (ifmsh->mshcfg.plink_timeout > 0)
  		ieee80211_sta_expire(sdata, ifmsh->mshcfg.plink_timeout * HZ);

  	mesh_path_expire(sdata);

  	changed = mesh_accept_plinks_update(sdata);

  	ieee80211_mbss_info_change_notify(sdata, changed);

  	mod_timer(&ifmsh->housekeeping_timer,

  		  round_jiffies(jiffies +
  				IEEE80211_MESH_HOUSEKEEPING_INTERVAL));

  }

  static void ieee80211_mesh_rootpath(struct ieee80211_sub_if_data *sdata)
  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	u32 interval;

  
  	mesh_path_tx_root_frame(sdata);

  
  	if (ifmsh->mshcfg.dot11MeshHWMPRootMode == IEEE80211_PROACTIVE_RANN)
  		interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
  	else
  		interval = ifmsh->mshcfg.dot11MeshHWMProotInterval;

  	mod_timer(&ifmsh->mesh_path_root_timer,

  		  round_jiffies(TU_TO_EXP_TIME(interval)));

  }

  static int
  ieee80211_mesh_build_beacon(struct ieee80211_if_mesh *ifmsh)
  {
  	struct beacon_data *bcn;
  	int head_len, tail_len;
  	struct sk_buff *skb;
  	struct ieee80211_mgmt *mgmt;
  	struct ieee80211_chanctx_conf *chanctx_conf;

  	struct mesh_csa_settings *csa;

  	enum nl80211_band band;

  	u8 *pos;
  	struct ieee80211_sub_if_data *sdata;
  	int hdr_len = offsetof(struct ieee80211_mgmt, u.beacon) +
  		      sizeof(mgmt->u.beacon);
  
  	sdata = container_of(ifmsh, struct ieee80211_sub_if_data, u.mesh);
  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  	band = chanctx_conf->def.chan->band;
  	rcu_read_unlock();
  
  	head_len = hdr_len +
  		   2 + /* NULL SSID */

  		   /* Channel Switch Announcement */
  		   2 + sizeof(struct ieee80211_channel_sw_ie) +

  		   /* Mesh Channel Switch Parameters */

  		   2 + sizeof(struct ieee80211_mesh_chansw_params_ie) +

  		   /* Channel Switch Wrapper + Wide Bandwidth CSA IE */
  		   2 + 2 + sizeof(struct ieee80211_wide_bw_chansw_ie) +
  		   2 + sizeof(struct ieee80211_sec_chan_offs_ie) +

  		   2 + 8 + /* supported rates */
  		   2 + 3; /* DS params */
  	tail_len = 2 + (IEEE80211_MAX_SUPP_RATES - 8) +
  		   2 + sizeof(struct ieee80211_ht_cap) +
  		   2 + sizeof(struct ieee80211_ht_operation) +
  		   2 + ifmsh->mesh_id_len +
  		   2 + sizeof(struct ieee80211_meshconf_ie) +
  		   2 + sizeof(__le16) + /* awake window */

  		   2 + sizeof(struct ieee80211_vht_cap) +
  		   2 + sizeof(struct ieee80211_vht_operation) +

  		   ifmsh->ie_len;
  
  	bcn = kzalloc(sizeof(*bcn) + head_len + tail_len, GFP_KERNEL);
  	/* need an skb for IE builders to operate on */
  	skb = dev_alloc_skb(max(head_len, tail_len));
  
  	if (!bcn || !skb)
  		goto out_free;
  
  	/*
  	 * pointers go into the block we allocated,
  	 * memory is | beacon_data | head | tail |
  	 */
  	bcn->head = ((u8 *) bcn) + sizeof(*bcn);
  
  	/* fill in the head */

  	mgmt = skb_put_zero(skb, hdr_len);

  	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  					  IEEE80211_STYPE_BEACON);
  	eth_broadcast_addr(mgmt->da);
  	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  	ieee80211_mps_set_frame_flags(sdata, NULL, (void *) mgmt);
  	mgmt->u.beacon.beacon_int =
  		cpu_to_le16(sdata->vif.bss_conf.beacon_int);
  	mgmt->u.beacon.capab_info |= cpu_to_le16(
  		sdata->u.mesh.security ? WLAN_CAPABILITY_PRIVACY : 0);
  
  	pos = skb_put(skb, 2);
  	*pos++ = WLAN_EID_SSID;
  	*pos++ = 0x0;

  	rcu_read_lock();
  	csa = rcu_dereference(ifmsh->csa);
  	if (csa) {

  		enum nl80211_channel_type ct;
  		struct cfg80211_chan_def *chandef;
  		int ie_len = 2 + sizeof(struct ieee80211_channel_sw_ie) +
  			     2 + sizeof(struct ieee80211_mesh_chansw_params_ie);

  		pos = skb_put_zero(skb, ie_len);

  		*pos++ = WLAN_EID_CHANNEL_SWITCH;
  		*pos++ = 3;
  		*pos++ = 0x0;
  		*pos++ = ieee80211_frequency_to_channel(
  				csa->settings.chandef.chan->center_freq);

  		bcn->csa_current_counter = csa->settings.count;

  		bcn->csa_counter_offsets[0] = hdr_len + 6;

  		*pos++ = csa->settings.count;
  		*pos++ = WLAN_EID_CHAN_SWITCH_PARAM;
  		*pos++ = 6;

  		if (ifmsh->csa_role == IEEE80211_MESH_CSA_ROLE_INIT) {

  			*pos++ = ifmsh->mshcfg.dot11MeshTTL;
  			*pos |= WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;
  		} else {
  			*pos++ = ifmsh->chsw_ttl;
  		}
  		*pos++ |= csa->settings.block_tx ?
  			  WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT : 0x00;
  		put_unaligned_le16(WLAN_REASON_MESH_CHAN, pos);
  		pos += 2;

  		put_unaligned_le16(ifmsh->pre_value, pos);

  		pos += 2;

  
  		switch (csa->settings.chandef.width) {
  		case NL80211_CHAN_WIDTH_40:
  			ie_len = 2 + sizeof(struct ieee80211_sec_chan_offs_ie);

  			pos = skb_put_zero(skb, ie_len);

  
  			*pos++ = WLAN_EID_SECONDARY_CHANNEL_OFFSET; /* EID */
  			*pos++ = 1;				    /* len */
  			ct = cfg80211_get_chandef_type(&csa->settings.chandef);
  			if (ct == NL80211_CHAN_HT40PLUS)
  				*pos++ = IEEE80211_HT_PARAM_CHA_SEC_ABOVE;
  			else
  				*pos++ = IEEE80211_HT_PARAM_CHA_SEC_BELOW;
  			break;
  		case NL80211_CHAN_WIDTH_80:
  		case NL80211_CHAN_WIDTH_80P80:
  		case NL80211_CHAN_WIDTH_160:
  			/* Channel Switch Wrapper + Wide Bandwidth CSA IE */
  			ie_len = 2 + 2 +
  				 sizeof(struct ieee80211_wide_bw_chansw_ie);

  			pos = skb_put_zero(skb, ie_len);

  
  			*pos++ = WLAN_EID_CHANNEL_SWITCH_WRAPPER; /* EID */
  			*pos++ = 5;				  /* len */
  			/* put sub IE */
  			chandef = &csa->settings.chandef;
  			ieee80211_ie_build_wide_bw_cs(pos, chandef);
  			break;
  		default:
  			break;
  		}

  	}
  	rcu_read_unlock();

  	if (ieee80211_add_srates_ie(sdata, skb, true, band) ||

  	    mesh_add_ds_params_ie(sdata, skb))

  		goto out_free;
  
  	bcn->head_len = skb->len;
  	memcpy(bcn->head, skb->data, bcn->head_len);
  
  	/* now the tail */
  	skb_trim(skb, 0);
  	bcn->tail = bcn->head + bcn->head_len;
  
  	if (ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||

  	    mesh_add_rsn_ie(sdata, skb) ||
  	    mesh_add_ht_cap_ie(sdata, skb) ||
  	    mesh_add_ht_oper_ie(sdata, skb) ||
  	    mesh_add_meshid_ie(sdata, skb) ||
  	    mesh_add_meshconf_ie(sdata, skb) ||
  	    mesh_add_awake_window_ie(sdata, skb) ||

  	    mesh_add_vht_cap_ie(sdata, skb) ||
  	    mesh_add_vht_oper_ie(sdata, skb) ||

  	    mesh_add_vendor_ies(sdata, skb))

  		goto out_free;
  
  	bcn->tail_len = skb->len;
  	memcpy(bcn->tail, skb->data, bcn->tail_len);

  	bcn->meshconf = (struct ieee80211_meshconf_ie *)
  					(bcn->tail + ifmsh->meshconf_offset);

  
  	dev_kfree_skb(skb);
  	rcu_assign_pointer(ifmsh->beacon, bcn);
  	return 0;
  out_free:
  	kfree(bcn);
  	dev_kfree_skb(skb);
  	return -ENOMEM;
  }
  
  static int

  ieee80211_mesh_rebuild_beacon(struct ieee80211_sub_if_data *sdata)

  {

  	struct beacon_data *old_bcn;
  	int ret;

  	old_bcn = rcu_dereference_protected(sdata->u.mesh.beacon,
  					    lockdep_is_held(&sdata->wdev.mtx));
  	ret = ieee80211_mesh_build_beacon(&sdata->u.mesh);

  	if (ret)
  		/* just reuse old beacon */

  		return ret;

  
  	if (old_bcn)
  		kfree_rcu(old_bcn, rcu_head);

  	return 0;

  }
  
  void ieee80211_mbss_info_change_notify(struct ieee80211_sub_if_data *sdata,
  				       u32 changed)
  {

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	unsigned long bits = changed;
  	u32 bit;
  
  	if (!bits)
  		return;
  
  	/* if we race with running work, worst case this work becomes a noop */
  	for_each_set_bit(bit, &bits, sizeof(changed) * BITS_PER_BYTE)
  		set_bit(bit, &ifmsh->mbss_changed);
  	set_bit(MESH_WORK_MBSS_CHANGED, &ifmsh->wrkq_flags);
  	ieee80211_queue_work(&sdata->local->hw, &sdata->work);

  }
  
  int ieee80211_start_mesh(struct ieee80211_sub_if_data *sdata)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	struct ieee80211_local *local = sdata->local;

  	u32 changed = BSS_CHANGED_BEACON |
  		      BSS_CHANGED_BEACON_ENABLED |
  		      BSS_CHANGED_HT |
  		      BSS_CHANGED_BASIC_RATES |
  		      BSS_CHANGED_BEACON_INT;

  	local->fif_other_bss++;
  	/* mesh ifaces must set allmulti to forward mcast traffic */
  	atomic_inc(&local->iff_allmultis);
  	ieee80211_configure_filter(local);

  	ifmsh->mesh_cc_id = 0;	/* Disabled */

  	/* register sync ops from extensible synchronization framework */
  	ifmsh->sync_ops = ieee80211_mesh_sync_ops_get(ifmsh->mesh_sp_id);

  	ifmsh->sync_offset_clockdrift_max = 0;

  	set_bit(MESH_WORK_HOUSEKEEPING, &ifmsh->wrkq_flags);

  	ieee80211_mesh_root_setup(ifmsh);

  	ieee80211_queue_work(&local->hw, &sdata->work);

  	sdata->vif.bss_conf.ht_operation_mode =
  				ifmsh->mshcfg.ht_opmode;

  	sdata->vif.bss_conf.enable_beacon = true;

  	changed |= ieee80211_mps_local_status_update(sdata);

  	if (ieee80211_mesh_build_beacon(ifmsh)) {
  		ieee80211_stop_mesh(sdata);
  		return -ENOMEM;
  	}

  	ieee80211_recalc_dtim(local, sdata);

  	ieee80211_bss_info_change_notify(sdata, changed);

  
  	netif_carrier_on(sdata->dev);

  	return 0;

  }
  
  void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata)
  {

  	struct ieee80211_local *local = sdata->local;

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	struct beacon_data *bcn;

  	netif_carrier_off(sdata->dev);

  	/* flush STAs and mpaths on this iface */
  	sta_info_flush(sdata);
  	mesh_path_flush_by_iface(sdata);

  	/* stop the beacon */

  	ifmsh->mesh_id_len = 0;

  	sdata->vif.bss_conf.enable_beacon = false;
  	clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED, &sdata->state);

  	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED);

  
  	/* remove beacon */

  	bcn = rcu_dereference_protected(ifmsh->beacon,

  					lockdep_is_held(&sdata->wdev.mtx));

  	RCU_INIT_POINTER(ifmsh->beacon, NULL);

  	kfree_rcu(bcn, rcu_head);

  	/* free all potentially still buffered group-addressed frames */
  	local->total_ps_buffered -= skb_queue_len(&ifmsh->ps.bc_buf);
  	skb_queue_purge(&ifmsh->ps.bc_buf);

  	del_timer_sync(&sdata->u.mesh.housekeeping_timer);

  	del_timer_sync(&sdata->u.mesh.mesh_path_root_timer);

  	del_timer_sync(&sdata->u.mesh.mesh_path_timer);

  	/* clear any mesh work (for next join) we may have accrued */
  	ifmsh->wrkq_flags = 0;
  	ifmsh->mbss_changed = 0;

  	local->fif_other_bss--;
  	atomic_dec(&local->iff_allmultis);
  	ieee80211_configure_filter(local);

  }

  static void ieee80211_mesh_csa_mark_radar(struct ieee80211_sub_if_data *sdata)
  {
  	int err;
  
  	/* if the current channel is a DFS channel, mark the channel as
  	 * unavailable.
  	 */
  	err = cfg80211_chandef_dfs_required(sdata->local->hw.wiphy,
  					    &sdata->vif.bss_conf.chandef,
  					    NL80211_IFTYPE_MESH_POINT);
  	if (err > 0)
  		cfg80211_radar_event(sdata->local->hw.wiphy,
  				     &sdata->vif.bss_conf.chandef, GFP_ATOMIC);
  }

  static bool
  ieee80211_mesh_process_chnswitch(struct ieee80211_sub_if_data *sdata,
  				 struct ieee802_11_elems *elems, bool beacon)
  {
  	struct cfg80211_csa_settings params;
  	struct ieee80211_csa_ie csa_ie;

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	struct ieee80211_supported_band *sband;

  	int err;

  	u32 sta_flags;

  	sdata_assert_lock(sdata);

  	sband = ieee80211_get_sband(sdata);
  	if (!sband)
  		return false;

  	sta_flags = 0;

  	switch (sdata->vif.bss_conf.chandef.width) {
  	case NL80211_CHAN_WIDTH_20_NOHT:
  		sta_flags |= IEEE80211_STA_DISABLE_HT;
  	case NL80211_CHAN_WIDTH_20:
  		sta_flags |= IEEE80211_STA_DISABLE_40MHZ;

  	case NL80211_CHAN_WIDTH_40:
  		sta_flags |= IEEE80211_STA_DISABLE_VHT;

  		break;
  	default:
  		break;
  	}
  
  	memset(&params, 0, sizeof(params));

  	err = ieee80211_parse_ch_switch_ie(sdata, elems, sband->band,

  					   sta_flags, sdata->vif.addr,
  					   &csa_ie);
  	if (err < 0)
  		return false;
  	if (err)
  		return false;

  	/* Mark the channel unavailable if the reason for the switch is
  	 * regulatory.
  	 */
  	if (csa_ie.reason_code == WLAN_REASON_MESH_CHAN_REGULATORY)
  		ieee80211_mesh_csa_mark_radar(sdata);

  	params.chandef = csa_ie.chandef;
  	params.count = csa_ie.count;

  	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, &params.chandef,

  				     IEEE80211_CHAN_DISABLED) ||
  	    !cfg80211_reg_can_beacon(sdata->local->hw.wiphy, &params.chandef,
  				     NL80211_IFTYPE_MESH_POINT)) {

  		sdata_info(sdata,
  			   "mesh STA %pM switches to unsupported channel (%d MHz, width:%d, CF1/2: %d/%d MHz), aborting
  ",
  			   sdata->vif.addr,
  			   params.chandef.chan->center_freq,
  			   params.chandef.width,
  			   params.chandef.center_freq1,
  			   params.chandef.center_freq2);
  		return false;
  	}
  
  	err = cfg80211_chandef_dfs_required(sdata->local->hw.wiphy,

  					    &params.chandef,
  					    NL80211_IFTYPE_MESH_POINT);

  	if (err < 0)
  		return false;

  	if (err > 0 && !ifmsh->userspace_handles_dfs) {
  		sdata_info(sdata,
  			   "mesh STA %pM switches to channel requiring DFS (%d MHz, width:%d, CF1/2: %d/%d MHz), aborting
  ",
  			   sdata->vif.addr,
  			   params.chandef.chan->center_freq,
  			   params.chandef.width,
  			   params.chandef.center_freq1,
  			   params.chandef.center_freq2);

  		return false;

  	}

  
  	params.radar_required = err;

  	if (cfg80211_chandef_identical(&params.chandef,
  				       &sdata->vif.bss_conf.chandef)) {
  		mcsa_dbg(sdata,
  			 "received csa with an identical chandef, ignoring
  ");
  		return true;
  	}

  
  	mcsa_dbg(sdata,
  		 "received channel switch announcement to go to channel %d MHz
  ",
  		 params.chandef.chan->center_freq);
  
  	params.block_tx = csa_ie.mode & WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT;

  	if (beacon) {

  		ifmsh->chsw_ttl = csa_ie.ttl - 1;

  		if (ifmsh->pre_value >= csa_ie.pre_value)
  			return false;
  		ifmsh->pre_value = csa_ie.pre_value;
  	}

  	if (ifmsh->chsw_ttl >= ifmsh->mshcfg.dot11MeshTTL)

  		return false;

  	ifmsh->csa_role = IEEE80211_MESH_CSA_ROLE_REPEATER;

  	if (ieee80211_channel_switch(sdata->local->hw.wiphy, sdata->dev,
  				     &params) < 0)
  		return false;

  
  	return true;

  }

  static void
  ieee80211_mesh_rx_probe_req(struct ieee80211_sub_if_data *sdata,
  			    struct ieee80211_mgmt *mgmt, size_t len)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	struct sk_buff *presp;
  	struct beacon_data *bcn;
  	struct ieee80211_mgmt *hdr;
  	struct ieee802_11_elems elems;
  	size_t baselen;

  	u8 *pos;

  	pos = mgmt->u.probe_req.variable;
  	baselen = (u8 *) pos - (u8 *) mgmt;
  	if (baselen > len)
  		return;

  	ieee802_11_parse_elems(pos, len - baselen, false, &elems);

  	if (!elems.mesh_id)
  		return;

  	/* 802.11-2012 10.1.4.3.2 */
  	if ((!ether_addr_equal(mgmt->da, sdata->vif.addr) &&
  	     !is_broadcast_ether_addr(mgmt->da)) ||
  	    elems.ssid_len != 0)
  		return;
  
  	if (elems.mesh_id_len != 0 &&
  	    (elems.mesh_id_len != ifmsh->mesh_id_len ||
  	     memcmp(elems.mesh_id, ifmsh->mesh_id, ifmsh->mesh_id_len)))
  		return;
  
  	rcu_read_lock();
  	bcn = rcu_dereference(ifmsh->beacon);
  
  	if (!bcn)
  		goto out;
  
  	presp = dev_alloc_skb(local->tx_headroom +
  			      bcn->head_len + bcn->tail_len);
  	if (!presp)
  		goto out;
  
  	skb_reserve(presp, local->tx_headroom);

  	skb_put_data(presp, bcn->head, bcn->head_len);
  	skb_put_data(presp, bcn->tail, bcn->tail_len);

  	hdr = (struct ieee80211_mgmt *) presp->data;
  	hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  					 IEEE80211_STYPE_PROBE_RESP);
  	memcpy(hdr->da, mgmt->sa, ETH_ALEN);

  	IEEE80211_SKB_CB(presp)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
  	ieee80211_tx_skb(sdata, presp);
  out:
  	rcu_read_unlock();
  }

  static void ieee80211_mesh_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
  					u16 stype,
  					struct ieee80211_mgmt *mgmt,
  					size_t len,
  					struct ieee80211_rx_status *rx_status)
  {

  	struct ieee80211_local *local = sdata->local;

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	struct ieee802_11_elems elems;
  	struct ieee80211_channel *channel;

  	size_t baselen;
  	int freq;

  	enum nl80211_band band = rx_status->band;

  
  	/* ignore ProbeResp to foreign address */
  	if (stype == IEEE80211_STYPE_PROBE_RESP &&

  	    !ether_addr_equal(mgmt->da, sdata->vif.addr))

  		return;
  
  	baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
  	if (baselen > len)
  		return;
  
  	ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,

  			       false, &elems);

  	/* ignore non-mesh or secure / unsecure mismatch */
  	if ((!elems.mesh_id || !elems.mesh_config) ||
  	    (elems.rsn && sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) ||
  	    (!elems.rsn && sdata->u.mesh.security != IEEE80211_MESH_SEC_NONE))

  		return;

  	if (elems.ds_params)

  		freq = ieee80211_channel_to_frequency(elems.ds_params[0], band);

  	else
  		freq = rx_status->freq;
  
  	channel = ieee80211_get_channel(local->hw.wiphy, freq);
  
  	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
  		return;

  	if (mesh_matches_local(sdata, &elems)) {
  		mpl_dbg(sdata, "rssi_threshold=%d,rx_status->signal=%d
  ",
  			sdata->u.mesh.mshcfg.rssi_threshold, rx_status->signal);
  		if (!sdata->u.mesh.user_mpm ||
  		    sdata->u.mesh.mshcfg.rssi_threshold == 0 ||
  		    sdata->u.mesh.mshcfg.rssi_threshold < rx_status->signal)
  			mesh_neighbour_update(sdata, mgmt->sa, &elems);
  	}

  
  	if (ifmsh->sync_ops)
  		ifmsh->sync_ops->rx_bcn_presp(sdata,
  			stype, mgmt, &elems, rx_status);

  	if (ifmsh->csa_role != IEEE80211_MESH_CSA_ROLE_INIT &&
  	    !sdata->vif.csa_active)

  		ieee80211_mesh_process_chnswitch(sdata, &elems, true);

  }

  int ieee80211_mesh_finish_csa(struct ieee80211_sub_if_data *sdata)
  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	struct mesh_csa_settings *tmp_csa_settings;
  	int ret = 0;

  	int changed = 0;

  
  	/* Reset the TTL value and Initiator flag */

  	ifmsh->csa_role = IEEE80211_MESH_CSA_ROLE_NONE;

  	ifmsh->chsw_ttl = 0;
  
  	/* Remove the CSA and MCSP elements from the beacon */
  	tmp_csa_settings = rcu_dereference(ifmsh->csa);

  	RCU_INIT_POINTER(ifmsh->csa, NULL);

  	if (tmp_csa_settings)
  		kfree_rcu(tmp_csa_settings, rcu_head);

  	ret = ieee80211_mesh_rebuild_beacon(sdata);
  	if (ret)
  		return -EINVAL;

  	changed |= BSS_CHANGED_BEACON;

  
  	mcsa_dbg(sdata, "complete switching to center freq %d MHz",
  		 sdata->vif.bss_conf.chandef.chan->center_freq);

  	return changed;

  }
  
  int ieee80211_mesh_csa_beacon(struct ieee80211_sub_if_data *sdata,

  			      struct cfg80211_csa_settings *csa_settings)

  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	struct mesh_csa_settings *tmp_csa_settings;
  	int ret = 0;
  
  	tmp_csa_settings = kmalloc(sizeof(*tmp_csa_settings),
  				   GFP_ATOMIC);
  	if (!tmp_csa_settings)
  		return -ENOMEM;
  
  	memcpy(&tmp_csa_settings->settings, csa_settings,
  	       sizeof(struct cfg80211_csa_settings));
  
  	rcu_assign_pointer(ifmsh->csa, tmp_csa_settings);
  
  	ret = ieee80211_mesh_rebuild_beacon(sdata);
  	if (ret) {
  		tmp_csa_settings = rcu_dereference(ifmsh->csa);

  		RCU_INIT_POINTER(ifmsh->csa, NULL);

  		kfree_rcu(tmp_csa_settings, rcu_head);
  		return ret;
  	}

  	return BSS_CHANGED_BEACON;

  }

  static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,

  			       struct ieee80211_mgmt *mgmt, size_t len,
  			       struct ieee802_11_elems *elems)

  {
  	struct ieee80211_mgmt *mgmt_fwd;
  	struct sk_buff *skb;
  	struct ieee80211_local *local = sdata->local;

  
  	skb = dev_alloc_skb(local->tx_headroom + len);
  	if (!skb)
  		return -ENOMEM;
  	skb_reserve(skb, local->tx_headroom);

  	mgmt_fwd = skb_put(skb, len);

  	elems->mesh_chansw_params_ie->mesh_ttl--;
  	elems->mesh_chansw_params_ie->mesh_flags &=
  		~WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;

  
  	memcpy(mgmt_fwd, mgmt, len);
  	eth_broadcast_addr(mgmt_fwd->da);
  	memcpy(mgmt_fwd->sa, sdata->vif.addr, ETH_ALEN);
  	memcpy(mgmt_fwd->bssid, sdata->vif.addr, ETH_ALEN);
  
  	ieee80211_tx_skb(sdata, skb);
  	return 0;
  }
  
  static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,
  			      struct ieee80211_mgmt *mgmt, size_t len)
  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	struct ieee802_11_elems elems;
  	u16 pre_value;

  	bool fwd_csa = true;

  	size_t baselen;

  	u8 *pos;

  
  	if (mgmt->u.action.u.measurement.action_code !=
  	    WLAN_ACTION_SPCT_CHL_SWITCH)
  		return;
  
  	pos = mgmt->u.action.u.chan_switch.variable;
  	baselen = offsetof(struct ieee80211_mgmt,
  			   u.action.u.chan_switch.variable);

  	ieee802_11_parse_elems(pos, len - baselen, true, &elems);

  	ifmsh->chsw_ttl = elems.mesh_chansw_params_ie->mesh_ttl;
  	if (!--ifmsh->chsw_ttl)

  		fwd_csa = false;
  
  	pre_value = le16_to_cpu(elems.mesh_chansw_params_ie->mesh_pre_value);
  	if (ifmsh->pre_value >= pre_value)
  		return;
  
  	ifmsh->pre_value = pre_value;

  	if (!sdata->vif.csa_active &&
  	    !ieee80211_mesh_process_chnswitch(sdata, &elems, false)) {

  		mcsa_dbg(sdata, "Failed to process CSA action frame");
  		return;
  	}

  	/* forward or re-broadcast the CSA frame */
  	if (fwd_csa) {

  		if (mesh_fwd_csa_frame(sdata, mgmt, len, &elems) < 0)

  			mcsa_dbg(sdata, "Failed to forward the CSA frame");
  	}

  }

  static void ieee80211_mesh_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,
  					  struct ieee80211_mgmt *mgmt,
  					  size_t len,
  					  struct ieee80211_rx_status *rx_status)
  {
  	switch (mgmt->u.action.category) {

  	case WLAN_CATEGORY_SELF_PROTECTED:
  		switch (mgmt->u.action.u.self_prot.action_code) {
  		case WLAN_SP_MESH_PEERING_OPEN:
  		case WLAN_SP_MESH_PEERING_CLOSE:
  		case WLAN_SP_MESH_PEERING_CONFIRM:
  			mesh_rx_plink_frame(sdata, mgmt, len, rx_status);
  			break;
  		}

  		break;

  	case WLAN_CATEGORY_MESH_ACTION:
  		if (mesh_action_is_path_sel(mgmt))
  			mesh_rx_path_sel_frame(sdata, mgmt, len);

  		break;

  	case WLAN_CATEGORY_SPECTRUM_MGMT:
  		mesh_rx_csa_frame(sdata, mgmt, len);
  		break;

  	}
  }

  void ieee80211_mesh_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
  				   struct sk_buff *skb)

  {
  	struct ieee80211_rx_status *rx_status;

  	struct ieee80211_mgmt *mgmt;
  	u16 stype;

  	sdata_lock(sdata);
  
  	/* mesh already went down */

  	if (!sdata->u.mesh.mesh_id_len)

  		goto out;

  	rx_status = IEEE80211_SKB_RXCB(skb);

  	mgmt = (struct ieee80211_mgmt *) skb->data;
  	stype = le16_to_cpu(mgmt->frame_control) & IEEE80211_FCTL_STYPE;
  
  	switch (stype) {
  	case IEEE80211_STYPE_PROBE_RESP:
  	case IEEE80211_STYPE_BEACON:
  		ieee80211_mesh_rx_bcn_presp(sdata, stype, mgmt, skb->len,
  					    rx_status);
  		break;

  	case IEEE80211_STYPE_PROBE_REQ:
  		ieee80211_mesh_rx_probe_req(sdata, mgmt, skb->len);
  		break;

  	case IEEE80211_STYPE_ACTION:
  		ieee80211_mesh_rx_mgmt_action(sdata, mgmt, skb->len, rx_status);
  		break;
  	}

  out:
  	sdata_unlock(sdata);

  }

  static void mesh_bss_info_changed(struct ieee80211_sub_if_data *sdata)
  {
  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  	u32 bit, changed = 0;
  
  	for_each_set_bit(bit, &ifmsh->mbss_changed,
  			 sizeof(changed) * BITS_PER_BYTE) {
  		clear_bit(bit, &ifmsh->mbss_changed);
  		changed |= BIT(bit);
  	}
  
  	if (sdata->vif.bss_conf.enable_beacon &&
  	    (changed & (BSS_CHANGED_BEACON |
  			BSS_CHANGED_HT |
  			BSS_CHANGED_BASIC_RATES |
  			BSS_CHANGED_BEACON_INT)))
  		if (ieee80211_mesh_rebuild_beacon(sdata))
  			return;
  
  	ieee80211_bss_info_change_notify(sdata, changed);
  }

  void ieee80211_mesh_work(struct ieee80211_sub_if_data *sdata)

  {

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	sdata_lock(sdata);
  
  	/* mesh already went down */

  	if (!sdata->u.mesh.mesh_id_len)

  		goto out;

  	if (ifmsh->preq_queue_len &&
  	    time_after(jiffies,
  		       ifmsh->last_preq + msecs_to_jiffies(ifmsh->mshcfg.dot11MeshHWMPpreqMinInterval)))
  		mesh_path_start_discovery(sdata);

  	if (test_and_clear_bit(MESH_WORK_HOUSEKEEPING, &ifmsh->wrkq_flags))

  		ieee80211_mesh_housekeeping(sdata);

  
  	if (test_and_clear_bit(MESH_WORK_ROOT, &ifmsh->wrkq_flags))
  		ieee80211_mesh_rootpath(sdata);

  
  	if (test_and_clear_bit(MESH_WORK_DRIFT_ADJUST, &ifmsh->wrkq_flags))

  		mesh_sync_adjust_tsf(sdata);

  	if (test_and_clear_bit(MESH_WORK_MBSS_CHANGED, &ifmsh->wrkq_flags))
  		mesh_bss_info_changed(sdata);

  out:
  	sdata_unlock(sdata);

  }

  void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
  {

  	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

  	static u8 zero_addr[ETH_ALEN] = {};

  	setup_timer(&ifmsh->housekeeping_timer,
  		    ieee80211_mesh_housekeeping_timer,
  		    (unsigned long) sdata);

  	ifmsh->accepting_plinks = true;

  	atomic_set(&ifmsh->mpaths, 0);

  	mesh_rmc_init(sdata);

  	ifmsh->last_preq = jiffies;

  	ifmsh->next_perr = jiffies;

  	ifmsh->csa_role = IEEE80211_MESH_CSA_ROLE_NONE;

  	/* Allocate all mesh structures when creating the first mesh interface. */
  	if (!mesh_allocated)
  		ieee80211s_init();

  
  	mesh_pathtbl_init(sdata);

  	setup_timer(&ifmsh->mesh_path_timer,

  		    ieee80211_mesh_path_timer,
  		    (unsigned long) sdata);

  	setup_timer(&ifmsh->mesh_path_root_timer,
  		    ieee80211_mesh_path_root_timer,
  		    (unsigned long) sdata);

  	INIT_LIST_HEAD(&ifmsh->preq_queue.list);

  	skb_queue_head_init(&ifmsh->ps.bc_buf);

  	spin_lock_init(&ifmsh->mesh_preq_queue_lock);

  	spin_lock_init(&ifmsh->sync_offset_lock);

  	RCU_INIT_POINTER(ifmsh->beacon, NULL);

  
  	sdata->vif.bss_conf.bssid = zero_addr;

  }

  
  void ieee80211_mesh_teardown_sdata(struct ieee80211_sub_if_data *sdata)
  {
  	mesh_rmc_free(sdata);
  	mesh_pathtbl_unregister(sdata);
  }