/*

   * Copyright (c) 2008, 2009 open80211s Ltd.

   * Author:     Luis Carlos Cobo <luisca@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/gfp.h>

  #include <linux/kernel.h>
  #include <linux/random.h>

  #include "ieee80211_i.h"

  #include "rate.h"

  #include "mesh.h"

  
  #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
  #define mpl_dbg(fmt, args...)	printk(KERN_DEBUG fmt, ##args)
  #else
  #define mpl_dbg(fmt, args...)	do { (void)(0); } while (0)
  #endif

  #define PLINK_GET_LLID(p) (p + 2)
  #define PLINK_GET_PLID(p) (p + 4)

  
  #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
  				jiffies + HZ * t / 1000))

  #define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
  #define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
  #define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
  #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
  #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)

  enum plink_event {
  	PLINK_UNDEFINED,
  	OPN_ACPT,
  	OPN_RJCT,
  	OPN_IGNR,
  	CNF_ACPT,
  	CNF_RJCT,
  	CNF_IGNR,
  	CLS_ACPT,
  	CLS_IGNR
  };

  static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  		enum ieee80211_self_protected_actioncode action,
  		u8 *da, __le16 llid, __le16 plid, __le16 reason);

  static inline
  void mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  {

  	atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);

  	mesh_accept_plinks_update(sdata);

  }
  
  static inline
  void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  {

  	atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);

  	mesh_accept_plinks_update(sdata);

  }
  
  /**
   * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
   *

   * @sta: mesh peer link to restart

   *

   * Locking: this function must be called holding sta->lock

   */
  static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  {

  	sta->plink_state = NL80211_PLINK_LISTEN;

  	sta->llid = sta->plid = sta->reason = 0;
  	sta->plink_retries = 0;

  }

  /*
   * NOTE: This is just an alias for sta_info_alloc(), see notes
   *       on it in the lifecycle management section!
   */

  static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,

  					 u8 *hw_addr, u32 rates,
  					 struct ieee802_11_elems *elems)

  {

  	struct ieee80211_local *local = sdata->local;

  	struct ieee80211_supported_band *sband;

  	struct sta_info *sta;

  	sband = local->hw.wiphy->bands[local->oper_channel->band];

  	if (local->num_sta >= MESH_MAX_PLINKS)

  		return NULL;

  	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);

  	if (!sta)
  		return NULL;

  	sta_info_move_state(sta, IEEE80211_STA_AUTH);
  	sta_info_move_state(sta, IEEE80211_STA_ASSOC);
  	sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);

  	set_sta_flag(sta, WLAN_STA_WME);

  	sta->sta.supp_rates[local->hw.conf.channel->band] = rates;

  	if (elems->ht_cap_elem)

  		ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
  						  elems->ht_cap_elem,

  						  &sta->sta.ht_cap);

  	rate_control_rate_init(sta);

  
  	return sta;
  }
  
  /**

   * __mesh_plink_deactivate - deactivate mesh peer link

   *
   * @sta: mesh peer link to deactivate
   *
   * All mesh paths with this peer as next hop will be flushed
   *

   * Locking: the caller must hold sta->lock

   */

  static bool __mesh_plink_deactivate(struct sta_info *sta)

  {

  	struct ieee80211_sub_if_data *sdata = sta->sdata;

  	bool deactivated = false;

  	if (sta->plink_state == NL80211_PLINK_ESTAB) {

  		mesh_plink_dec_estab_count(sdata);

  		deactivated = true;
  	}

  	sta->plink_state = NL80211_PLINK_BLOCKED;

  	mesh_path_flush_by_nexthop(sta);

  
  	return deactivated;

  }

  /**

   * mesh_plink_deactivate - deactivate mesh peer link

   *
   * @sta: mesh peer link to deactivate
   *
   * All mesh paths with this peer as next hop will be flushed
   */
  void mesh_plink_deactivate(struct sta_info *sta)
  {

  	struct ieee80211_sub_if_data *sdata = sta->sdata;
  	bool deactivated;

  	spin_lock_bh(&sta->lock);

  	deactivated = __mesh_plink_deactivate(sta);

  	sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
  	mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
  			    sta->sta.addr, sta->llid, sta->plid,
  			    sta->reason);

  	spin_unlock_bh(&sta->lock);

  
  	if (deactivated)
  		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);

  }

  static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,

  		enum ieee80211_self_protected_actioncode action,
  		u8 *da, __le16 llid, __le16 plid, __le16 reason) {

  	struct ieee80211_local *local = sdata->local;

  	struct sk_buff *skb;

  	struct ieee80211_mgmt *mgmt;
  	bool include_plid = false;

  	u16 peering_proto = 0;

  	u8 *pos, ie_len = 4;
  	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
  		      sizeof(mgmt->u.action.u.self_prot);
  
  	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
  			    hdr_len +
  			    2 + /* capability info */
  			    2 + /* AID */
  			    2 + 8 + /* supported rates */
  			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
  			    2 + sdata->u.mesh.mesh_id_len +
  			    2 + sizeof(struct ieee80211_meshconf_ie) +

  			    2 + sizeof(struct ieee80211_ht_cap) +
  			    2 + sizeof(struct ieee80211_ht_info) +

  			    2 + 8 + /* peering IE */
  			    sdata->u.mesh.ie_len);

  	if (!skb)
  		return -1;
  	skb_reserve(skb, local->hw.extra_tx_headroom);

  	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
  	memset(mgmt, 0, hdr_len);

  	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  					  IEEE80211_STYPE_ACTION);

  	memcpy(mgmt->da, da, ETH_ALEN);

  	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);

  	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);

  	mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
  	mgmt->u.action.u.self_prot.action_code = action;

  	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
  		/* capability info */
  		pos = skb_put(skb, 2);
  		memset(pos, 0, 2);

  		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {

  			/* AID */
  			pos = skb_put(skb, 2);

  			memcpy(pos + 2, &plid, 2);

  		}

  		if (ieee80211_add_srates_ie(&sdata->vif, skb) ||
  		    ieee80211_add_ext_srates_ie(&sdata->vif, skb) ||

  		    mesh_add_rsn_ie(skb, sdata) ||
  		    mesh_add_meshid_ie(skb, sdata) ||
  		    mesh_add_meshconf_ie(skb, sdata))
  			return -1;

  	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
  		if (mesh_add_meshid_ie(skb, sdata))
  			return -1;

  	}

  	/* Add Mesh Peering Management element */

  	switch (action) {

  	case WLAN_SP_MESH_PEERING_OPEN:

  		break;

  	case WLAN_SP_MESH_PEERING_CONFIRM:

  		ie_len += 2;

  		include_plid = true;
  		break;

  	case WLAN_SP_MESH_PEERING_CLOSE:

  		if (plid) {
  			ie_len += 2;

  			include_plid = true;
  		}

  		ie_len += 2;	/* reason code */

  		break;

  	default:
  		return -EINVAL;

  	}

  	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
  		return -ENOMEM;

  	pos = skb_put(skb, 2 + ie_len);

  	*pos++ = WLAN_EID_PEER_MGMT;

  	*pos++ = ie_len;

  	memcpy(pos, &peering_proto, 2);
  	pos += 2;

  	memcpy(pos, &llid, 2);

  	pos += 2;

  	if (include_plid) {

  		memcpy(pos, &plid, 2);

  		pos += 2;

  	}

  	if (action == WLAN_SP_MESH_PEERING_CLOSE) {

  		memcpy(pos, &reason, 2);

  		pos += 2;

  	}

  
  	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
  		if (mesh_add_ht_cap_ie(skb, sdata) ||
  		    mesh_add_ht_info_ie(skb, sdata))
  			return -1;
  	}

  	if (mesh_add_vendor_ies(skb, sdata))
  		return -1;

  	ieee80211_tx_skb(sdata, skb);

  	return 0;
  }

  void mesh_neighbour_update(u8 *hw_addr, u32 rates,
  		struct ieee80211_sub_if_data *sdata,
  		struct ieee802_11_elems *elems)

  {

  	struct ieee80211_local *local = sdata->local;

  	struct sta_info *sta;

  	rcu_read_lock();

  	sta = sta_info_get(sdata, hw_addr);

  	if (!sta) {

  		rcu_read_unlock();

  		/* Userspace handles peer allocation when security is enabled
  		 * */

  		if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)

  			cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
  					elems->ie_start, elems->total_len,
  					GFP_KERNEL);
  		else

  			sta = mesh_plink_alloc(sdata, hw_addr, rates, elems);

  		if (!sta)

  			return;

  		if (sta_info_insert_rcu(sta)) {

  			rcu_read_unlock();

  			return;

  		}

  	}
  
  	sta->last_rx = jiffies;

  	sta->sta.supp_rates[local->hw.conf.channel->band] = rates;

  	if (mesh_peer_accepts_plinks(elems) &&

  			sta->plink_state == NL80211_PLINK_LISTEN &&

  			sdata->u.mesh.accepting_plinks &&
  			sdata->u.mesh.mshcfg.auto_open_plinks)

  		mesh_plink_open(sta);

  	rcu_read_unlock();

  }
  
  static void mesh_plink_timer(unsigned long data)
  {
  	struct sta_info *sta;
  	__le16 llid, plid, reason;

  	struct ieee80211_sub_if_data *sdata;

  	/*
  	 * This STA is valid because sta_info_destroy() will
  	 * del_timer_sync() this timer after having made sure
  	 * it cannot be readded (by deleting the plink.)
  	 */

  	sta = (struct sta_info *) data;

  	if (sta->sdata->local->quiescing) {
  		sta->plink_timer_was_running = true;
  		return;
  	}

  	spin_lock_bh(&sta->lock);

  	if (sta->ignore_plink_timer) {
  		sta->ignore_plink_timer = false;

  		spin_unlock_bh(&sta->lock);

  		return;
  	}

  	mpl_dbg("Mesh plink timer for %pM fired on state %d
  ",
  		sta->sta.addr, sta->plink_state);

  	reason = 0;
  	llid = sta->llid;
  	plid = sta->plid;

  	sdata = sta->sdata;

  
  	switch (sta->plink_state) {

  	case NL80211_PLINK_OPN_RCVD:
  	case NL80211_PLINK_OPN_SNT:

  		/* retry timer */
  		if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
  			u32 rand;

  			mpl_dbg("Mesh plink for %pM (retry, timeout): %d %d
  ",
  				sta->sta.addr, sta->plink_retries,
  				sta->plink_timeout);

  			get_random_bytes(&rand, sizeof(u32));
  			sta->plink_timeout = sta->plink_timeout +
  					     rand % sta->plink_timeout;
  			++sta->plink_retries;

  			mod_plink_timer(sta, sta->plink_timeout);

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
  					    sta->sta.addr, llid, 0, 0);

  			break;
  		}

  		reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);

  		/* fall through on else */

  	case NL80211_PLINK_CNF_RCVD:

  		/* confirm timer */
  		if (!reason)

  			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);

  		sta->plink_state = NL80211_PLINK_HOLDING;

  		mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));

  		spin_unlock_bh(&sta->lock);

  		mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
  				    sta->sta.addr, llid, plid, reason);

  		break;

  	case NL80211_PLINK_HOLDING:

  		/* holding timer */

  		del_timer(&sta->plink_timer);

  		mesh_plink_fsm_restart(sta);

  		spin_unlock_bh(&sta->lock);

  		break;
  	default:

  		spin_unlock_bh(&sta->lock);

  		break;
  	}

  }

  #ifdef CONFIG_PM
  void mesh_plink_quiesce(struct sta_info *sta)
  {
  	if (del_timer_sync(&sta->plink_timer))
  		sta->plink_timer_was_running = true;
  }
  
  void mesh_plink_restart(struct sta_info *sta)
  {
  	if (sta->plink_timer_was_running) {
  		add_timer(&sta->plink_timer);
  		sta->plink_timer_was_running = false;
  	}
  }
  #endif

  static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
  {
  	sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
  	sta->plink_timer.data = (unsigned long) sta;
  	sta->plink_timer.function = mesh_plink_timer;
  	sta->plink_timeout = timeout;

  	add_timer(&sta->plink_timer);
  }
  
  int mesh_plink_open(struct sta_info *sta)
  {
  	__le16 llid;

  	struct ieee80211_sub_if_data *sdata = sta->sdata;

  	if (!test_sta_flag(sta, WLAN_STA_AUTH))

  		return -EPERM;

  	spin_lock_bh(&sta->lock);

  	get_random_bytes(&llid, 2);
  	sta->llid = llid;

  	if (sta->plink_state != NL80211_PLINK_LISTEN) {

  		spin_unlock_bh(&sta->lock);

  		return -EBUSY;
  	}

  	sta->plink_state = NL80211_PLINK_OPN_SNT;

  	mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));

  	spin_unlock_bh(&sta->lock);

  	mpl_dbg("Mesh plink: starting establishment with %pM
  ",
  		sta->sta.addr);

  	return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,

  				   sta->sta.addr, llid, 0, 0);

  }
  
  void mesh_plink_block(struct sta_info *sta)
  {

  	struct ieee80211_sub_if_data *sdata = sta->sdata;
  	bool deactivated;

  	spin_lock_bh(&sta->lock);

  	deactivated = __mesh_plink_deactivate(sta);

  	sta->plink_state = NL80211_PLINK_BLOCKED;

  	spin_unlock_bh(&sta->lock);

  
  	if (deactivated)
  		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);

  }

  void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,

  			 size_t len, struct ieee80211_rx_status *rx_status)
  {

  	struct ieee80211_local *local = sdata->local;

  	struct ieee802_11_elems elems;
  	struct sta_info *sta;
  	enum plink_event event;

  	enum ieee80211_self_protected_actioncode ftype;

  	size_t baselen;

  	bool deactivated, matches_local = true;

  	u8 ie_len;
  	u8 *baseaddr;
  	__le16 plid, llid, reason;

  #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
  	static const char *mplstates[] = {

  		[NL80211_PLINK_LISTEN] = "LISTEN",
  		[NL80211_PLINK_OPN_SNT] = "OPN-SNT",
  		[NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
  		[NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
  		[NL80211_PLINK_ESTAB] = "ESTAB",
  		[NL80211_PLINK_HOLDING] = "HOLDING",
  		[NL80211_PLINK_BLOCKED] = "BLOCKED"

  	};
  #endif

  	/* need action_code, aux */
  	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
  		return;

  	if (is_multicast_ether_addr(mgmt->da)) {
  		mpl_dbg("Mesh plink: ignore frame from multicast address");
  		return;
  	}

  	baseaddr = mgmt->u.action.u.self_prot.variable;
  	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
  	if (mgmt->u.action.u.self_prot.action_code ==

  						WLAN_SP_MESH_PEERING_CONFIRM) {

  		baseaddr += 4;

  		baselen += 4;

  	}
  	ieee802_11_parse_elems(baseaddr, len - baselen, &elems);

  	if (!elems.peering) {

  		mpl_dbg("Mesh plink: missing necessary peer link ie
  ");
  		return;
  	}

  	if (elems.rsn_len &&
  			sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {

  		mpl_dbg("Mesh plink: can't establish link with secure peer
  ");
  		return;
  	}

  	ftype = mgmt->u.action.u.self_prot.action_code;
  	ie_len = elems.peering_len;
  	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
  	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
  	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
  							&& ie_len != 8)) {

  		mpl_dbg("Mesh plink: incorrect plink ie length %d %d
  ",
  		    ftype, ie_len);

  		return;
  	}

  	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
  				(!elems.mesh_id || !elems.mesh_config)) {

  		mpl_dbg("Mesh plink: missing necessary ie
  ");
  		return;
  	}
  	/* Note the lines below are correct, the llid in the frame is the plid
  	 * from the point of view of this host.
  	 */

  	memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);

  	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||

  	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
  		memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);

  	rcu_read_lock();

  	sta = sta_info_get(sdata, mgmt->sa);

  	if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {

  		mpl_dbg("Mesh plink: cls or cnf from unknown peer
  ");

  		rcu_read_unlock();

  		return;
  	}

  	if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {

  		mpl_dbg("Mesh plink: Action frame from non-authed peer
  ");
  		rcu_read_unlock();
  		return;
  	}

  	if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {

  		rcu_read_unlock();

  		return;
  	}
  
  	/* Now we will figure out the appropriate event... */
  	event = PLINK_UNDEFINED;

  	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
  	    (!mesh_matches_local(&elems, sdata))) {

  		matches_local = false;

  		switch (ftype) {

  		case WLAN_SP_MESH_PEERING_OPEN:

  			event = OPN_RJCT;
  			break;

  		case WLAN_SP_MESH_PEERING_CONFIRM:

  			event = CNF_RJCT;
  			break;

  		default:

  			break;
  		}

  	}
  
  	if (!sta && !matches_local) {
  		rcu_read_unlock();

  		reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);

  		llid = 0;

  		mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
  				    mgmt->sa, llid, plid, reason);

  		return;

  	} else if (!sta) {

  		/* ftype == WLAN_SP_MESH_PEERING_OPEN */

  		u32 rates;

  
  		rcu_read_unlock();

  		if (!mesh_plink_free_count(sdata)) {
  			mpl_dbg("Mesh plink error: no more free plinks
  ");
  			return;
  		}
  
  		rates = ieee80211_sta_get_rates(local, &elems, rx_status->band);

  		sta = mesh_plink_alloc(sdata, mgmt->sa, rates, &elems);

  		if (!sta) {

  			mpl_dbg("Mesh plink error: plink table full
  ");
  			return;
  		}

  		if (sta_info_insert_rcu(sta)) {

  			rcu_read_unlock();
  			return;
  		}

  		event = OPN_ACPT;

  		spin_lock_bh(&sta->lock);

  	} else if (matches_local) {

  		spin_lock_bh(&sta->lock);

  		switch (ftype) {

  		case WLAN_SP_MESH_PEERING_OPEN:

  			if (!mesh_plink_free_count(sdata) ||

  			    (sta->plid && sta->plid != plid))

  				event = OPN_IGNR;
  			else
  				event = OPN_ACPT;
  			break;

  		case WLAN_SP_MESH_PEERING_CONFIRM:

  			if (!mesh_plink_free_count(sdata) ||

  			    (sta->llid != llid || sta->plid != plid))

  				event = CNF_IGNR;
  			else
  				event = CNF_ACPT;
  			break;

  		case WLAN_SP_MESH_PEERING_CLOSE:

  			if (sta->plink_state == NL80211_PLINK_ESTAB)

  				/* Do not check for llid or plid. This does not
  				 * follow the standard but since multiple plinks
  				 * per sta are not supported, it is necessary in
  				 * order to avoid a livelock when MP A sees an
  				 * establish peer link to MP B but MP B does not
  				 * see it. This can be caused by a timeout in
  				 * B's peer link establishment or B beign
  				 * restarted.
  				 */
  				event = CLS_ACPT;
  			else if (sta->plid != plid)
  				event = CLS_IGNR;
  			else if (ie_len == 7 && sta->llid != llid)
  				event = CLS_IGNR;
  			else
  				event = CLS_ACPT;
  			break;
  		default:
  			mpl_dbg("Mesh plink: unknown frame subtype
  ");

  			spin_unlock_bh(&sta->lock);

  			rcu_read_unlock();

  			return;
  		}

  	} else {
  		spin_lock_bh(&sta->lock);

  	}

  	mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d
  ",
  		mgmt->sa, mplstates[sta->plink_state],

  		le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
  		event);

  	reason = 0;
  	switch (sta->plink_state) {
  		/* spin_unlock as soon as state is updated at each case */

  	case NL80211_PLINK_LISTEN:

  		switch (event) {
  		case CLS_ACPT:
  			mesh_plink_fsm_restart(sta);

  			spin_unlock_bh(&sta->lock);

  			break;
  		case OPN_ACPT:

  			sta->plink_state = NL80211_PLINK_OPN_RCVD;

  			sta->plid = plid;
  			get_random_bytes(&llid, 2);
  			sta->llid = llid;
  			mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_OPEN,
  					    sta->sta.addr, llid, 0, 0);
  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CONFIRM,
  					    sta->sta.addr, llid, plid, 0);

  			break;
  		default:

  			spin_unlock_bh(&sta->lock);

  			break;
  		}
  		break;

  	case NL80211_PLINK_OPN_SNT:

  		switch (event) {
  		case OPN_RJCT:
  		case CNF_RJCT:

  			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);

  		case CLS_ACPT:
  			if (!reason)

  				reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);

  			sta->reason = reason;

  			sta->plink_state = NL80211_PLINK_HOLDING;

  			if (!mod_plink_timer(sta,
  					     dot11MeshHoldingTimeout(sdata)))
  				sta->ignore_plink_timer = true;
  
  			llid = sta->llid;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CLOSE,
  					    sta->sta.addr, llid, plid, reason);

  			break;
  		case OPN_ACPT:
  			/* retry timer is left untouched */

  			sta->plink_state = NL80211_PLINK_OPN_RCVD;

  			sta->plid = plid;
  			llid = sta->llid;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CONFIRM,
  					    sta->sta.addr, llid, plid, 0);

  			break;
  		case CNF_ACPT:

  			sta->plink_state = NL80211_PLINK_CNF_RCVD;

  			if (!mod_plink_timer(sta,
  					     dot11MeshConfirmTimeout(sdata)))
  				sta->ignore_plink_timer = true;

  			spin_unlock_bh(&sta->lock);

  			break;
  		default:

  			spin_unlock_bh(&sta->lock);

  			break;
  		}
  		break;

  	case NL80211_PLINK_OPN_RCVD:

  		switch (event) {
  		case OPN_RJCT:
  		case CNF_RJCT:

  			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);

  		case CLS_ACPT:
  			if (!reason)

  				reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);

  			sta->reason = reason;

  			sta->plink_state = NL80211_PLINK_HOLDING;

  			if (!mod_plink_timer(sta,
  					     dot11MeshHoldingTimeout(sdata)))
  				sta->ignore_plink_timer = true;
  
  			llid = sta->llid;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
  					    sta->sta.addr, llid, plid, reason);

  			break;
  		case OPN_ACPT:
  			llid = sta->llid;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CONFIRM,
  					    sta->sta.addr, llid, plid, 0);

  			break;
  		case CNF_ACPT:

  			del_timer(&sta->plink_timer);

  			sta->plink_state = NL80211_PLINK_ESTAB;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_inc_estab_count(sdata);
  			ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);

  			mpl_dbg("Mesh plink with %pM ESTABLISHED
  ",
  				sta->sta.addr);

  			break;
  		default:

  			spin_unlock_bh(&sta->lock);

  			break;
  		}
  		break;

  	case NL80211_PLINK_CNF_RCVD:

  		switch (event) {
  		case OPN_RJCT:
  		case CNF_RJCT:

  			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);

  		case CLS_ACPT:
  			if (!reason)

  				reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);

  			sta->reason = reason;

  			sta->plink_state = NL80211_PLINK_HOLDING;

  			if (!mod_plink_timer(sta,
  					     dot11MeshHoldingTimeout(sdata)))
  				sta->ignore_plink_timer = true;
  
  			llid = sta->llid;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CLOSE,
  					    sta->sta.addr, llid, plid, reason);

  			break;

  		case OPN_ACPT:

  			del_timer(&sta->plink_timer);

  			sta->plink_state = NL80211_PLINK_ESTAB;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_inc_estab_count(sdata);
  			ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);

  			mpl_dbg("Mesh plink with %pM ESTABLISHED
  ",
  				sta->sta.addr);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CONFIRM,
  					    sta->sta.addr, llid, plid, 0);

  			break;
  		default:

  			spin_unlock_bh(&sta->lock);

  			break;
  		}
  		break;

  	case NL80211_PLINK_ESTAB:

  		switch (event) {
  		case CLS_ACPT:

  			reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);

  			sta->reason = reason;

  			deactivated = __mesh_plink_deactivate(sta);

  			sta->plink_state = NL80211_PLINK_HOLDING;

  			llid = sta->llid;

  			mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));

  			spin_unlock_bh(&sta->lock);

  			if (deactivated)
  				ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);

  			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
  					    sta->sta.addr, llid, plid, reason);

  			break;
  		case OPN_ACPT:
  			llid = sta->llid;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata,
  					    WLAN_SP_MESH_PEERING_CONFIRM,
  					    sta->sta.addr, llid, plid, 0);

  			break;
  		default:

  			spin_unlock_bh(&sta->lock);

  			break;
  		}
  		break;

  	case NL80211_PLINK_HOLDING:

  		switch (event) {
  		case CLS_ACPT:

  			if (del_timer(&sta->plink_timer))

  				sta->ignore_plink_timer = 1;

  			mesh_plink_fsm_restart(sta);

  			spin_unlock_bh(&sta->lock);

  			break;
  		case OPN_ACPT:
  		case CNF_ACPT:
  		case OPN_RJCT:
  		case CNF_RJCT:
  			llid = sta->llid;
  			reason = sta->reason;

  			spin_unlock_bh(&sta->lock);

  			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
  					    sta->sta.addr, llid, plid, reason);

  			break;
  		default:

  			spin_unlock_bh(&sta->lock);

  		}
  		break;
  	default:

  		/* should not get here, PLINK_BLOCKED is dealt with at the

  		 * beginning of the function

  		 */

  		spin_unlock_bh(&sta->lock);

  		break;
  	}

  
  	rcu_read_unlock();

  }